Peptides for use in a method for the prevention and / or treatment of cancer

Abstract

The present invention refers to specific peptides, or pharmaceutical compositions comprising thereof, for use in a method for the prevention and / or treatment of cancer.

Description

[0001] PEPTIDES FOR USE IN A METHOD FOR THE PREVENTION AND / OR

[0002] TREATMENT OF CANCER

[0003] FIELD OF THE INVENTION

[0004] The present invention refers to the medical field. Particularly, the present invention refers to specific peptides, or pharmaceutical compositions comprising thereof, for use in a method for the prevention and / or treatment of cancer.

[0005] STATE OF THE ART

[0006] Pericytes, which were first discovered in the 1870s, are described as cells embedded between the basement membrane and endothelial cells of capillaries. They were named pericytes in the 1920s when researchers observed that the endothelial cells of the capillaries were usually surrounded by pericytes, where they could regulate the vasoconstriction response. Further research showed that pericytes, together with endothelial cells, the basement membrane, and vascular smooth muscle cells, constitute the basic structure of human capillaries. Pericytes play an important role in forming the vascular wall, maintaining the vascular barrier, ensuring the stability of blood vessels, and participating in the maintenance of homeostasis in the human body.

[0007] The TME refers to the internal and external environment of tumor cells during their growth and metastasis. The composition of the TME is related to different tumor tissue types, and generally includes tumor cells, immune cells, blood vessels, the extracellular matrix, and bioactive molecules. Furthermore, the TME affects the occurrence, development, and metastasis of malignant tumors, and induces immune suppression, immune tolerance, and tumor angiogenesis.

[0008] As a component of the TME, pericytes interact with and mutually influence the TME. It is mainly reflected in the following six aspects [1]: Pericytes deviate from endothelial cells and vascular basement membrane in the TME, and the phenotype changes simultaneously. The change of pericytes could damage the local vascular barrier and facilitate the budding proliferation of endothelial cells and tumor angiogenesis. In the later stages of malignancy, these abnormal blood vessels form the hypoxic TME, promoting immune tolerance and affecting the therapeutic efficacy of chemotherapeutic drugs. [2] Before tumor metastasis, pericytes at the secondary sites can detach from vessels, gain phenotypic transformation, and increase the synthesis of extracellular matrix to create a premetastatic niche conducive to the colonization and invasion of hematogenous metastatic cancer cells. [3] Pericytes and cancer cells influence each other through paracrine effects to promote pericyte aggregation and angiogenesis, as well as immune tolerance and drug tolerance of cancer cells. [4] In the TME, the disorder of various signalling pathways makes it difficult for pericytes to recruit and play normal physiological functions, thus making the new vessels show the characteristics of immature and high permeability and promoting the formation of the hypoxic and acidic microenvironment in malignant tumor. [5] There is a bi-directional dialogue between pericytes and tumor-associated macrophages (TAMs). Pericytes can induce the infiltration and polarization of M2 phenotype macrophages, while TAMs can maintain the pericyte-like phenotype of mesenchymal stem cells in the vascular niche and secrete cytokines conducive to angiogenesis. [6] The impaired vessels result in forming the hypoxic TME which enables the production of various EMT-induced signals and stimulates the epithelial-mesenchymal transformation (EMT) of cancer cells. The transformed cancer cells also exhibit the phenotype and function of pericytes, clustering into local blood vessels and causing the occurrence of tumor metastasis.

[0009] On the other hand, there is a lack of knowledge of the pathogenesis and mechanisms of progression different types of cancer leading to ineffective therapeutic strategies. For instance, glioblastoma is the most aggressive brain cancer as it is one of the most difficult cancers to treat due to the immune scape of the tumor cells which infiltrate and spread in the brain parenchyma surrounding microblood vessels where pericytes (PCs) are located, supporting tumor growth.

[0010] Since there is an unmet medical need of finding reliable strategies for treating cancer, the present invention is focused on solving this problem and an innovative therapeutical strategy, based on the above explained interaction between pericytes and tumor cells, is herein provided.

[0011] DESCRIPTION OF THE INVENTION

[0012] The present invention refers to specific peptides, or pharmaceutical compositions comprising thereof, for the prevention and / or treatment of cancer.

[0013] Particularly, the therapy strategy provided by the present invention refers to the use of specific peptides (hereinafter “peptides of the invention”) or a pharmaceutical composition comprising thereof. The peptides of the invention comprise or consist of SEQ ID NO: 1 (RIHMVYSKRSGKPRGYAFIEY) or SEQ ID NO: 2 (H4MVYSKRSGKPRGYAFIEY), analogues, or salt forms thereof. The present invention also includes conservative mutations of the peptides of the invention and also peptides having homology / identity of at least 90% with the peptide of the invention.

[0014] The preferred candidates may comprise analogues of the peptides of SEQ ID NO: 1 or SEQ ID NO: 2. For instance, they may have a phosphoserine residue in at least one of the serine positions, preferably a phosphoserine residue at position 10 or 7 or both of them:

[0015] RIHMVYSKRS(PO3H2)GKPRGYAFIEY

[0016] RIHMVYS(PO3H2)KRSGKPRGYAFIEY

[0017] RIHMVYS(PO3H2)KRS(PO3H2)GKPRGYAFIEY or at position 9

[0018] IHMVYSKRS(PO3H2)GKPRGYAFIEY

[0019] On the other hand, the methionine at position 4 or at position 3 may be oxidised, giving rise to the following structures:

[0020] RIHM(O)VYSKRSGKPRGYAFIEY

[0021] IHM(O)VYSKRSGKPRGYAFIEY

[0022] The peptide may comprise both phosphoserine and oxidized methionine residues:

[0023] RIHM(O)VYSKRS(PO3H2)GKPRGYAFIEY

[0024] IHM(O)VYSKRS(PO3H2)GKPRGYAFIEY

[0025] RIHM(O)VYS(PO3H2)KRSGKPRGYAFIEY

[0026] IHM(O)VYS(PO3H2)KRSGKPRGYAFIEY

[0027] RIHM(O)VYS(PO3H2)KRS(PO3H2)GKPRGYAFIEY

[0028] IHM(O)VYS(PO3H2)KRS(PO3H2)GKPRGYAFIEY

[0029] “M(O)” represents oxidized methionine and “S(PO3H2)” represents phosphoserine.

[0030] Moreover, the peptides of the invention may comprise an acetylation of one or both of the lysine residues at position 8 and / or 12 (SEQ ID NO: 1) or at position 7 and / or 11 (SEQ ID NO: On the other hand, the peptides have a N-terminus and a C-terminus. The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C- terminal tail, carboxy tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH).

[0031] Such as it is shown in Example 2, a peptide which comprises or consists of SEQ ID NO: 1 (RIHMVYSKRSGKPRGYAFIEY) with a phosphoserine (pS) (PO3H2) residue at position 10 (RIHMVYSKRpSGKPRGYAFIEY) is assayed as proof-of-concept (P140). The assayed peptide reduces glioma cells-PC interactions required for glioma cells proliferation and survival (Example 2.1) and the intravenous therapy with the peptide of the invention promotes tumor cell elimination (Example 2.2).

[0032] So, the goal of the present invention was finding therapeutic strategies able to prevent interactions between glioma cells and PCs (as proof-of-concept) and, therefore, promoting PC anti-tumor functions, as a possible treatment against Cerebral Nervous System tumours like glioma, glioblastoma (GB) or paediatric gliomas.

[0033] However, since there are also influences and interactions between PCs and other cancer cells, beyond glioma cells, the therapeutic strategy of the present invention can be extrapolated to other types of cancer caused by said mechanism of action.

[0034] Other examples of cancer diseases wherein the interaction of PC and cancer cells plays an important role are, for instance: Pancreatic cancer [Wu, zhichong et al. "Pericyte stem cells induce Ly6G+ cell accumulation and immunotherapy resistance in pancreatic cancer." EMBO reports vol. 24,4 (2023): e56524. doi:10.15252 / embr.202256524], Colon and bowel Cancer [Mustafa, A et al. "Potential crosstalk between pericytes and cathepsins in the tumour microenvironment. "Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie vol. 164 (2023): 114932. dot: 10.1016 / j.biopha.2023.114932], liver cancer [Li, Xiaobo et al. “TCAF2 in Pericytes Promotes Colorectal Cancer Liver Metastasis via Inhibiting Cold-Sensing TPPM8 Channel. ” Advanced science (W einheim, Baden- Wurttemberg, Germany) vol. 10,30 (2023): e2302717. doi: 10.1002 / 'advs.202302777], bone Cancer [Chang, Le et al. "Pericytes in sarcomas of bone. ” Medical oncology (Northwood, London, England) vol. 32,7 (2015): 202. doi: 10.1007 / s 12032-015-06 1 -6], breast cancer and brain tumours [Ippolitov, Danyyl etal. “Brain Microvascular Pericyte s-More than Bystanders in Breast Cancer Brain Metastasis. " Cells vol. 11,8 1263. 8 Apr. 2022, doi:10.3390 / cellsll081263], mouth Cancer [do Valle, Isabella Bittencourt et al. “The participation of tumor residing pericytes in oral squamous cell carcinoma. "Scientific reports vol. 13,1 5460. 4 Apr. 2023, doi:10.1038 / s41598-023-32528- 7], lung cancer [Bagley, Rebecca G et al. “Pericytes from human non-small cell lung carcinomas: an attractive target for anti-angiogenic therapy." Microvascular research vol. 71,3 (2006): 163-74. doi: 10.1016 / j. mvr.2006.03.002], melanoma [lose Humberto Trevino-Villarreal et al., Effect of pericytes on melanoma development.. JCO 30, 83- 83(2012).DOI: 10.1200 / jco.2012.30.30_ suppl. 'S'j] or renal Cancer [Cao, Yun et al. “Pericyte coverage of differentiated vessels inside tumor vasculature is an independent unfavorable prognostic factor for patients with clear cell renal cell carcinoma. ’’ Cancervol. 119,2 (2013): 313-24. doi:10.1002 / cncr.27746 .

[0035] This means that, the therapeutic strategy of the present invention could be used in the treatment of all types of cancer wherein the interaction of PC and cancer cells plays an important role, as documented above.

[0036] So, the first embodiment of the present invention refers to a peptide selected from the group consisting of SEQ ID NO: 1 or SEQ ID NO: 2, or a peptide having an identity of sequence of at least 95% with SEQ ID NO: 1 or SEQ ID NO: 2, for use in a method for the prevention and / or treatment of cancer.

[0037] The second embodiment of the present invention refers to a pharmaceutical composition comprising a peptide selected from the group consisting of SEQ ID NO: 1 or SEQ ID NO: 2, or a peptide having an identity of sequence of at least 95% with SEQ ID NO: 1 or SEQ ID NO: 2, and, optionally, pharmaceutically acceptable excipients or carriers, for use in a method for the prevention and / or treatment of cancer.

[0038] In a preferred embodiment, the present invention refers to a peptide or pharmaceutical composition for use, according to any of the previous claims, in a method for the prevention and / or treatment of cancer, wherein the method comprises: i) pre-treating pericytes with the peptide and ii) administering the pre-treated pericytes, or the secretome derived thereof (Figure 8), to the patient (Figure 13).

[0039] In a preferred embodiment, the cancer disease to be prevented and / or treated is promoted by the interaction of pericytes and cancer cells, and the treatment comprises preventing interactions between cancer cells and pericytes and thus, to let pericytes to induce their antitumor properties and enhance the anti-tumor immune responses.

[0040] In a preferred embodiment, the cancer disease to be prevented and / or treated is Cerebral Nervous System tumours, pancreatic cancer, colon and bowel cancer, liver cancer, bone cancer, breast cancer, brain tumours, mouth cancer, lung cancer, melanoma or renal cancer.

[0041] In a preferred embodiment, the cancer disease to be prevented and / or treated is glioma, glioblastoma or paediatric gliomas. In a preferred embodiment, at least one serine is phosphorylated and / or the methionine is oxidised in the SEQ ID NO: 1 or SEQ ID NO: 2.

[0042] In a preferred embodiment, the serine at position 10 of SEQ ID NO: 1, or the serine at position 9 of SEQ ID NO: 2, is phosphorylated comprising a phosphoserine residue at said position.

[0043] In a preferred embodiment, the pharmaceutical composition is administered at a dosage of from about 100 ng to about 5 mg, preferably from about 25 ng a 5 mg.

[0044] Alternatively, the present invention refers to a method for preventing and / or treating the above cited types of cancer which comprises administering a therapeutically effective dose or amount of the pharmaceutical composition comprising the peptide / s of the invention.

[0045] Any route of administration may be used, for instance systemic or local administration, although intravenous administration is preferred.

[0046] For the purpose of the present invention the following terms are defined:

[0047] • The expression cancer disease “promoted by the interaction of pericytes and tumor cells” refers to any cancer disease wherein tumor cells interact with pericytes to condition them on their own benefit needed to proliferate and survive.

[0048] • The term "comprising" means "including", but not limited to what follows the term "comprising". Thus, the use of the term "comprising" indicates that the elements listed are necessary or mandatory, but that other elements are optional and may or may not be present.

[0049] • The term "consisting of' means "including" but is limited to what follows the term "consisting of'. Thus, the term "consists of' indicates that the elements listed are mandatory, and that other elements may not be present.

[0050] • By “therapeutically effective dose or amount” of a composition comprising the peptide of the invention is intended an amount that, when administered as described herein, brings about a positive therapeutic response in a subject suffering from cancer. The exact amount required will vary from subject to subject, depending on the species, age, and general condition of the subject, the severity of the condition being treated, mode of administration, and the like An appropriate “effective” amount in any individual case may be determined by one of ordinary skill in the art using routine experimentation, based upon the information provided herein. • The term "pharmacological composition," "therapeutic composition," "therapeutic formulation" or "pharmaceutically acceptable formulation" can mean, but is in no way limited to, a composition or formulation that allows for the effective distribution of the peptide provided by the invention.

[0051] • The term "pharmaceutically acceptable" or "pharmacologically acceptable" can mean, but is in no way limited to, entities and compositions that do not produce an adverse, allergic, or other untoward reaction when administered to an animal, or a human, as appropriate.

[0052] • The term "pharmaceutically acceptable carrier" or "pharmacologically acceptable carrier" can mean, but is in no way limited to, any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents, and the like, compatible with pharmaceutical administration. Suitable carriers are described in the most recent edition of Remington's Pharmaceutical Sciences, a standard reference text in the field, which is incorporated herein by reference. Preferred examples of such carriers or diluents include, but are not limited to, water, saline, finger's solutions, dextrose solution, and 5% human serum albumin. Liposomes and non-aqueous vehicles such as fixed oils may also be used. The use of such media and agents for pharmaceutically active substances is well known in the art. Except insofar as any conventional media or agent is incompatible with the active compound, use thereof in the compositions is contemplated. Supplementary active compounds can also be incorporated into the compositions.

[0053] • The term "systemic administration" refers to a route of administration that is, e g., enteral or parenteral, and results in the systemic distribution of an agent leading to systemic absorption or accumulation of drugs in the blood stream followed by distribution throughout the entire body. Suitable forms, in part, depend upon the use or the route of entry, for example oral, transdermal, or by injection. Such forms should not prevent the composition or formulation from reaching a target cell (i.e., a cell to which the negatively charged polymer is desired to be delivered to). For example, pharmacological compositions injected into the blood stream should be soluble. Other factors are known in the art and include considerations such as toxicity and forms which prevent the composition or formulation from exerting its effect. Administration routes which lead to systemic absorption include, without limitations: intravenous, subcutaneous, intraperitoneal, inhalation, oral, intrapulmonary and intramuscular. The rate of entry of a drug into the circulation has been shown to be a function of molecular weight or size. The use of a liposome or other drug carrier comprising the compounds of the instant invention can potentially localize the drug, for example, in certain tissue types, such as the tissues of the reticular endothelial system (RES). A liposome formulation which can facilitate the association of drug with the surface of cells, such as, lymphocytes and macrophages is also useful.

[0054] • The term "local administration" refers to a route of administration in which the agent is delivered to a site that is apposite or proximal, e.g., within about 10 cm, to the site of the lesion or disease.

[0055] • The term "conservative mutations" refers to the substitution, deletion or addition of nucleic acids that alter, add or delete a single amino acid or a small number of amino acids in a coding sequence where the nucleic acid alterations result in the substitution of a chemically similar amino acid. Amino acids that may serve as conservative substitutions for each other include the following: Basic: Arginine (R), Lysine (K), Histidine (H); Acidic: Aspartic acid (D), Glutamic acid (E), Asparagine (N), Glutamine (Q); hydrophilic: Glycine (G), Alanine (A), Valine (V), Leucine (L), Isoleucine (I); Hydrophobic: Phenylalanine (F), Tyrosine (Y), Tryptophan (W); Sulfur-containing: Methionine (M), Cysteine (C). In addition, sequences that differ by conservative variations are generally homologous.

[0056] • By "homology" is meant the nucleotide sequence of two or more nucleic acid molecules or two or more nucleic acid or amino acid sequences is partially or completely identical. In certain embodiments the homologous nucleic acid or amino acid sequence has 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% sequence similarity or identity to a nucleic acid encoding the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO:2, respectively. "Homologs" can be naturally occurring or created by artificial synthesis of one or more nucleic acids having related sequences, or by modification of one or more nucleic acid to produce related nucleic acids. Nucleic acids are homologous when they are derived, naturally or artificially, from a common ancestor sequence (e.g., orthologs or paralogs). If the homology between two nucleic acids is not expressly described, homology can be inferred by a nucleic acid comparison between two or more sequences. If the sequences demonstrate some degree of sequence similarity, for example, greater than about 30% at the primary amino acid structure level, it is concluded that they share a common ancestor. For purposes of the present invention, genes are homologous if the nucleic acid sequences are sufficiently similar to allow recombination and / or hybridization under low stringency conditions. In addition, polypeptides are regarded as homologous if their nucleic acid sequences are sufficiently similar to allow recombination or hybridization under low stringency conditions, and optionally they demonstrate membrane repair activity, and optionally they can be recognized by (i.e., cross-react with) an antibody specific for an epitope contained within the amino acid sequence of at least one of SEQ ID NOs: 1 or 2.

[0057] • The term "analogues" can mean, but is in no way limited to, chemical compositions, for example, nucleic acids, nucleotides, polypeptides or amino acids that have a structure similar to, but not identical to, the native compound.

[0058] Description of the figures

[0059] Figure 1. The CMA inhibitor peptide reduces GB-PC interaction required for GB proliferation and survival. (A-E) Proliferation, adhesion and viability assay: GB cells alone were treated with CMA inhibitor (P140) or control peptide (scramble, from peptide 140, i.e., a peptide with the same sequence but with different positions of the amino acid residues) (pCT) or cocultured (1 :1) with peptide-pretreated PCs (PCCGB) with several concentrations for 48 hours. (A) Representative figure of luminescence related to proliferation of GB-U871uciferase cell line. (B) Quantification of luminescence for 10 mM of P140. Means ± standard error of at least, 3 experiments are shown, * p<0,05 expressed as fold overPCCGB control. (C) Scheme of cell adhesion assay. (D) RFP fluorescence in the wells (belonging to the GB that adhered to PC) was measured at 488 nm. Graph represents percentage of adhesion relative to fluorescent levels of control GB cells alone of at least 5 experiments with several GB cell lines ** p<0,01; (E) Detection of GB cell death by LIVE / DEAD far red-fluorescent reactive dye (far red- fluorescent dye), following coculture for different time points with pretreated or not PCs (CT) with pCT or Pl 40 and compared to cell death in GB cells cocultured with NAc-treated PC as positive control. Gating strategy to identify DiD+ GB-labeled cell population is shown (Left). Representative flow cytometry histogram and bar graph showing quantification of dead cell percentages from at least 4 independent experiments with different GB cell lines, *P < 0.05, **P < 0.01 or ***P < 0.001.

[0060] Figure 2. Intravenous therapy with the peptide 140 promotes tumor cell elimination. (A)Timeline of xenografts and treatment. Three weeks after xenografts, mice were treated intravenously with four doses of control peptide (pCT) or peptide 140 (P140). The first two doses were applied on consecutive days and the last two were administered every three days. One week after the last dose, mice were euthanized, and organs were extracted. (B) Xenografts of GB tumor cells from mice intravenously treated with different concentrations of control peptide (pCT) and peptide 140 (P140). STEM121 was used to stain GB cells. Control GB brains without treatment show tumor cell mass and tumor cell infiltration (arrows in Bl, 2). The dose-response of 3 peptide concentrations (50 total pg / mouse / dose: 2.5 mg / kg, 25 total pg / mouse / dose: 1.25 mg / kg and 12.5 total pg / mouse / dose: 0.65 mg / kg) was analyzed. Control peptide therapy did not affect tumor cell infiltration at any concentration (B3, 4, 7, 8, 12, 13), showing tumor proliferation around dentate gyrus (DG), choroid plexus (cp) and fimbria (fi), as in controls. In P140 therapy grafted brains, GB cells were not detected at 0.5 ug / pl dose (B5, B6) while tumor masses started to be detected as the peptide concentration was reduced (B10, 14, 15). Scale bars: 100 pm. All results are shown using the U87 GB line, 4 weeks after therapy, and are representative of at least three independent experiments using both U87 or U251 GB cell lines, independently. (C) Relative quantification of STEM 121 positive cells related to tumor cells per brain. (D) Morphometric measurement of tumor size related to the surface area of the tumor cell mass. All results are mean+SD from at least three independent experiments using both U251 and U87 GB lines, independently; *p < 0.05, **p < 0.01.

[0061] Figure 3. The peptide 140 reaches tumor niche and accumulates in peritumoral areas as the control peptide. Control peptide (pCT) or peptide 140 (Pl 40) labelled with Alexa Fluor- 488 (AF488) was injected intravenously to 6 GB-xenografted mice to control their localization in the brain after 24h (Dentate gyrus (DG); Choroid plexus (cp)). (A) Peptide accumulation (in green) was analyzed in the tumor niche using STEM121 to stain GB cells (in red). (B) Colocalization of the peptide with PCs was identified staining the pericyte marker PDGFR0 (in red). (C) Colocalization of the peptide with astroglia cells was identified using the astrocytes marker GFAP. (D) Colocalization with microglia cells was detected by Ibal expression. Scale bars: 100 pm.

[0062] Figure 4. Phagocytic populations associated to the tumor are reduced in GB mice treated with peptide 140.

[0063] Iba-1 immunopositive cells are abundant in tumor areas (Al) and host peritumoral brain parenchyma (Al, 2, 3). pCT therapy shows infiltration of activated microglia associated to the tumor cell areas (A4-6). The P140 therapy shows accumulation of microgliosis (arrows in A7- 9) around grafted areas and close to previous tumorigenesis that was eliminated around the thalamus (TH). (B) CD68 immunostaining exhibited positive results only in GB control tumor graft areas (B1-B3). Similar staining is shown in pCT therapy (B4-B6) whereas CD68+cells were hardly detected with P140 therapy (B7-B9). Blood vessel (v); Dentate gyrus (DG); fimbria (fi); Choroid plexus (cp). Scale bars: 100 pm. (C) Relative quantification of Iba-1 immune-positive particles (pixels) in total brain. (D) Quantification of CD68 positive cells in total brain. All results are mean+SD from at least, three independent experiments using both U251 and U87 GB lines, independently; ***p < 0.001.

[0064] Figure 5. Brain infiltration of T-cell populations associated to the tumor are reduced in GB mice treated with peptide 140.

[0065] Characterization of infiltrating T cells marked with CD3, CD8, CD4 and FOXP3 in xenografts. GB cells were stained with STEM121. Images show infiltration of CD3+ cells in control and pCT treated mice, while P140 treated mice just show remaining T cells after tumor elimination. CD8+and CD4+tumor-associated T cells, including those expressing FOXP3+, were found in intratumoral areas, showing no differences between GB control and pCT treated mice. Pl 40 treated mice showed that the major remaining T cells were CD8+with hardly detection of FOXP3 expression. Scale bars: 100 pm.

[0066] Figure 6. P140 prevents PC interaction with other types of cancer cells.

[0067] Adhesion assay of (A) lung (A427) and (B) liver (HepG2) cancer cells, labelled with Dil and cocultured with a WT PC monolayer pretreated with 10 pM P140 / PCt for 48 h. Graph represents mean ± SD percentage of adhesion relative to fluorescent levels of control cancer cells alone of at least, 4 independent experiments with both cell lines; **p < 0.001; *p < 0.01.

[0068] Figure 7. P140 prevents GB-induced CMA aberrant upregulation but it does not inhibit PC CMA, nor macroautophagy.

[0069] (A) CMA activity was measured by the number of puncta relative to CMA substrates at the lysosomal membrane and expressed by the KFERQ-PA-mCherry reporter in PCt / P140-treated PCs alone or cocultured with GB cells for 24 to 72 h and compared to basal activity in control PCs. Nuclei were stained with DAPI (blue). Scale bar: 50 pm. All data represent mean ± SD obtained from at least, five experiments represented as dots, independently; ns means no significant, ** / ?<0.01, ***p<0.001. (B) Immunoblot of LC3 in PCs PCt / P140-treated or not (control, CT) for 48 h and incubated with lysosomal inhibitors (LI) 6 h before lysis. Densitometric quantification represents LC3-II / LC3-I ratio whereas lysosomal degradation inhibition is detected by the increase in LC3-II intensity. COX-2 was used as an activation control. Tubulin was used as loading control. All data represent mean ± SD obtained from three experiments represented as dots, independently; **p < 0.01. (C) Macroautophagy flux was measured by the number of puncta relative to autophagosomes (APG; yellow, red+green) and autophagolysosomes (ALY, red) expressed by the mCherry-GFP-LC3 reporter in PCt or P 140- treated GB -conditioned PCs (GBCPCs) from 24 to 72 h and compared incubated with lysosomal inhibitors (LI). Nuclei were stained with DAPI (blue). Scale bar: 50 pm. All data represent mean ± SD obtained from three experiments represented as dots, independently; ns means no significant, *p<0.05, **p<0.01, ***p<0.001.

[0070] Figure 8. P140 promotes an antitumoral and proinflammatory secretome in PCs.

[0071] ELISA measuring murine SPARC (A), Lumican (B), Vitamin D (C), ILip (D), IFNy (E) and Angiotensin (F) by PCs at basal condition and treated with PCt or P140 (10 pM) before coculture with GB cells (GBCPC) for 72 h. All data represent mean ± SD from at least two independent experiments represented as dots; ns means no significant, *p < 0.05, **p < 0.01, *** / ? < 0.001.

[0072] Figure 9. P140 intravenous therapy prevents tumorigenesis of GSCs and promotes inflammatory anti-tumor immune responses in peritumoral areas.

[0073] (A) Timeline of xenografts and treatment. Three weeks after xenografts, mice were treated intravenously with three doses of control peptide (PCt) or peptide P140 (Pl 40) The first two doses were applied on consecutive days and third one was administered every three days. Three days after the last dose, mice were euthanized, and brain and lymph nodes were extracted. (B) STEM121 was used as a GB cell marker. Nuclear antigen Ki67 (green) shows proliferative cells. Dashed line shows tumor formation (GB control) around dentate gyrus (DG). Images on the right show magnification tumor cell infiltration next to the fimbria (fi). GB tumor cells are hardly detected in P140-treated grafted brains, with only a few proliferative cells (arrows). Scale bars: 100 pm. All results are representative of at least three independent experiments. (C) Relative quantification of STEM121 / ki67 positive cells related to tumor cells per brain, represented as dots. (D) Morphometric measurement of tumor size related to the surface area of the tumor cell mass. All results are mean+SD from at least, three independent experiments; ns = not significant; *p < 0.05, **p < 0.01, ***p < 0.001. (E) Ibal (red) and IFNY (green) immunopositive cells are abundant in tumor areas and host peritumoral brain parenchyma. Intravenous administration of PCt shows infiltration of activated microglia around tumor cell areas, whereas perivascular areas are rarely marked. The Pl 40 therapy shows accumulation of activated microglia around graft areas, and close to previous tumorigenesis that was eliminated around the hippocampus (HP). Scale bars: 100 pm. (F) Relative quantification of Ibal and IFNy immune-positive particles (pixels) both in total brain and perivascular areas. All results are mean+SD from at least, three independent experiments; ns = not significant; *p < 0.05. (G) CD68 immunostaining exhibited positive results solely in GB control tumor graft areas. Similar staining is shown in PCt therapy. However, parenchyma and perivascular areas of mice treated with the P140 show heightened reactivity in the peritumoral niche. All shown results are representative of at least, three independent experiments. Scale bars: 100 pm. (H) Quantification of CD68 positive cells in total brain and perivascular areas. All results are mean+SD from at least, three independent experiments.

[0074] Figure 10. Expression of negative regulators of T cell activation is reduced in P140- treated mice.

[0075] Flow cytometry analysis of PD-1, CTLA4 and FoxP3 expression in CD4+ T cells from central lymph nodes of mice treated with intravenous PCt or Pl 40. Data represent mean ± SD obtained from at least, three independent experiments using both GB lines U87, U251, and patient- derived GSCs, independently; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.

[0076] Figure 11. P140 crosses the blood-brain barrier and accumulates specifically in phagocytic populations and not in neurons.

[0077] Control peptide (PCt) or peptide P140 (P140) labelled with AlexaFluor-488 (AF488) were injected intravenously to GB-xenografted mice in order to control the reaching and accumulation in the brain after 24 h. Peptide accumulation was analyzed in GB cells (A) marked with STEM121, PCs (B) marked with PDGFRp, astroglia cells (C) marked with GFAP, microglial cells (D) marked with Ibal and neural cells (E) marked with NeuN. (A) Xenografts of GB tumor cells (in red) from mice intravenously treated AF488-PCt and AF488-P140 (in green). Both peptides reach tumor areas around the dentate gyrus (DG) and choroid plexus (cp). PCt accumulates around and inside tumor cells (A1-A3, marked with arrows), whereas Pl 40 only accumulates in the peritumoral niche (A5-A7). Scale bars: 100 pm. (B) PCs (in red) show co-localization with both control and P140 peptides (marked with arrows), with a higher uptake of P140. Scale bars: 100 pm. (C) PCt was found (marked with arrows) in astroglia cells (in red) in contrast with Pl 40, which was hardly detected to be accumulated. Scale bars: 100 pm. (D) Microglial cells (in red) were found with P140 accumulation, whereas PCt was diffusely distributed. Scale bars: 100 pm. (E) Neurons (in red) show co-localization with control peptide (arrows in El) whereas Pl 40 was distributed only around them (E2). Scale bars: 100 pm.

[0078] Figure 12. P140 impairs GB progression in an immunocompromised GB mouse model with just the innate immune response.

[0079] (A) Nodescid immunocompromised mice with nonfunctional T / B cells, were xenografted with human GSCs and treated intravenously with three doses of control peptide (PCt) or peptide Pl 40 (Pl 40), for one week, after 3 weeks of tumor cell mass induction. Three days after the last dose, mice were euthanized and STEM121 was used as a GB cell marker. Nuclear antigen Ki-67 shows proliferative cells. Dashed line shows tumor formation (GB control) around dentate gyrus (DG). Scale bars: 100 pm. All results are representative of at least three independent experiments.

[0080] Figure 13. Peptide-pretreated PCs intravenous treatment prevent GB proliferation in mice.

[0081] (A) Timeline of xenografts and treatment. Mice were treated intravenously with peptide- pretreated PC three weeks after xenograft. Two weeks after treatment, mice were euthanized, and brain and lymphoid nods were extracted. (B) Xenografts of GB tumor cells of mice intravenously treated with peptide-pretreated (control peptide, PCt, or peptide P140, P140) exofucosylated PCs. STEM121 was used as a GB cell marker. Arrows show tumor formation in GB control (dashed line in Bl magnification) around dentate gyrus (DG). PCt-pretreat PC therapy representative image and magnification (B2) shows an infiltration of tumor cells (arrows) next to the fimbria (fi). GB tumor cells are hardly detected in P140-pretreated PC therapy grafted brains, with only a few cells (arrows in B3) near choroid plexus (cp). Scale bars: 100 pm. All experiments were done using U87 and U251 GB cell lines and are representative of at least three independent experiments. (C) Quantification of STEM121 positive cells related to tumor cells per brain in untreated control mice (CT) and mice treated with PCt / P140-PC. (D) Morphometric measurement of tumor size related to the surface area of the tumor cell mass in untreated control mice (CT) and mice treated with PCt / P140-PC. GB control mice show an irregular shape GB mice intravenously treated with PCt-pretreat PCs show no difference with controls, and GB mice treated with P140-pretreated PCs didn’t show tumor masses out of five grafted mice. (E) Representative images of Ibal immunostainings. Ibal immunopositive cells are abundant in tumor areas (El) and infiltrated peri tumoral brain parenchyma around the thalamus (TH; E2, 3). PCt-pretreat PC therapy shows tumor-associated microglia around tumor cell areas (arrows in E4) whereas peritumoral perivascular areas are rarely marked (E5, 6). The P140-pretreated PC therapy shows accumulation of activated microglia (arrows in E7-9) around grafted areas, and close to previous tumorigenesis that was eliminated around the thalamus (TH; E8). V: blood vessel. Scale bars: 100 pm. (F) Relative quantification of Iba-1 immune-positive particles (pixels) both in total brain and perivascular (PV) areas in untreated control mice (CT) and mice treated with PCt / P140-PC. (G) Representative images of CD68 immunostainings. CD68 immunostaining exhibited positive results solely in GB control tumor graft areas (G1-G3, arrows in Gl). A similar staining appears in PCt-pretreat PC therapy (G4-G6, marked with arrows). However, no positive staining was found in the grafted area (G7) and only parenchyma and perivascular areas (G8, 9) of mice treated with the P140-pretreated PC therapy show heightened reactivity. TH: thalamus; V: blood vessel. Scale bars: 100 pm. (H) Quantification of CD68 positive cells total brain and perivascular (PV) areas in untreated control mice (CT) and mice treated with PCt / P140-PC. All results are represented as mean±SD from at least, three independent experiments using both U251 and U87 GB lines. At least three mice were analyzed per condition, represented as dots; ns = not significant; *p < 0.05, **p < 0.01, ****p < 0.0001.

[0082] Detailed description of the invention

[0083] The present invention is illustrated by means of the Examples set below without the intention of limiting its scope of protection.

[0084] Example 1. MATERIAL AND METHODS

[0085] Discovery phase

[0086] Example 1.1. Isolation and coculture

[0087] [1:1] of murine brain pericytes from C57BL / 6 or C57BL / 6-Tg (ACTB-EGFP)lOsb / J (Charles River Laboratory) mice and human GB cell lines (U87, U251 and U373) for different time points kinetic was done following the methods already described [Valdor et al., 2017, Oncotarget],

[0088] Example 1.1. Proliferation Assays Luciferase activity was measured in GB-U87 cell co-cultured during 48 hours with pretreated PC-GFP cells with or without (C) control peptide (pC) or inhibitor peptide (pl) at several concentrations and 1 hour previously to add Glioblastoma cells. The effect of the peptides in GB-U87 cells alone was compared.

[0089] Example 1.2. Adhesion assays

[0090] GB-U251, -U273 labeled with Dil (cell tracker, Therm ophiser), or GB-U87 cells expressing RedFluorescenceProtein, were cocultured on a monolayer culture of PCs for 48 h. Cells were lysed after washing away non adhered cells with media, and remaining RFP fluorescence in the wells (belonging to the GB that adhered to PC) was measured at 488 nm (588-nm. emission).

[0091] Example 1.3. Survival assays

[0092] GB cells were analyzed using Dil labeling solution for tracking and separation of cells. GB cell death was determined using LIVE / DEAD Fixable far red Dead Cell Stain Kit, (ThermoFisher). Stained cells were analyzed by flow cytometry using a FACSCanto flow cytometer (BD Bioscience) and data were analyzed with Kaluza analysis software (Beckman Coulter).

[0093] Example 1.4. Mice

[0094] Male and female mice of eight to 12 weeks old WT C57BL / 6 (Charles River Laboratories) were maintained in pathogen-free conditions in the animal facilities of the Biomedical Research Institute of Murcia Virgen de la Arrixaca. All animal procedures were approved and performed according to the guidelines set by the Institutional Animal Care and Use Committee.

[0095] Example 1.5. Xenografts of human GB cells and therapy

[0096] Cell pellets (5 x 106cells) from human GB cells (U87 and U251 GB lines) were grafted into C57BL / 6 wild type mice brains. Xenografts were performed as previously described in an immunocompetent mouse model [Molina et al., Front.cell.Dev., 2022], Cell pellets, prepared as hanging drops, were grafted into mice. Xenografts (1 pellet / mouse) were introduced into the right hemisphere through a small craniotomy (2-3 mm from the midline, approximately 1 mm behind the bregma) at 2.5 mm depth, using a stereotactic apparatus and a Pasteur pipette hand- pulled to an internal diameter of 0.38 mm. This produced grafts that integrated into the occipital cortex or the hippocampus. Three weeks post-grafting, after tumor cell mass was established, mice were treated intravenously through tail injection with different doses of the peptide (4 doses of 50 pg each per mouse: 10 mg / kg, 4 doses of 25 pg per mouse: 5 mg / kg or 4 doses of 12.5 pg per mouse: 2.5 mg / kg) to analyze a dose response comparing to those none treated or treated with a control peptide. Four weeks after therapies, mice were sacrificed, and brains were fixed in 4% buffered formalin (Panreac Quimica). All procedures were repeated four times and analyzed in each experimental line (A total of 20 mice for any experimental line).

[0097] Example 1.6. Immunohistochemistry

[0098] Brains were paraffin embedded and processed by the Pathology facility (IMIB Virgen de la Arrixaca) as described previously [Valdor et al„ 2019, PNAS], Three-micrometer thick serial sections were obtained from paraffin embedded samples using an automatic rotary microtome (Thermo Scientific). For colorimetric immunolabeling, sections were incubated overnight at 4°C with mouse anti-human STEM121 (Cellartis), goat anti-Iba-1 (Abeam), rat anti-CD68 (Abdserotec), rabbit anti-CD3 (Dako-Agilent), rabbit anti-CD4 (Abeam), rabbit anti-CD8 (Abeam), rat anti-FOXP3 (EBioscience), primary antibodies. Sections were finally incubated with the corresponding 3-3 'Diaminobenci dine (DAB) secondary antibodies (Vector Labs) and hematoxylin counterstained. Positive immunoreaction was identified as a dark-brown precipitated. An automatic digital slide scanner (Pannoramic MIDI II-3DHistech) and Quantitative Pathology & Bioimage Analysis Qupath-0.2.3 software were used for analysis of histological sections, and acquisition of images. Morphometric measurements and quantification of cells were also performed using ImageJ (NIH, United States) software.

[0099] All determination were performed in brains of at least n = 5 mice per experimental group and four separate experiments.

[0100] Example 1.7. For Peptide localization and immunofluorescence

[0101] Peptidel40 or control peptide labeled with Alexa fluor 488 kindly provided by Professor S. Muller [Macri et al., 2015, Autophagy; Monneaux et al. Eur J Immunol 2003; Page et al., PLoS ONE 2009] were injected intravenously (4 doses of 50 mg per mouse) and analyzed by immunofluorescence after 24 fours. For brain fixation, brain tissue immunofluorescence and microscopy, we followed the methods already described [Valdor et al., 2019, PNAS], Tumor cells were detected with mouse anti-human STEM121 (Cellartis). PCs in blood microvessels of peritumoral areas were identified using a goat anti-mouse antibody (Neuromics) against the pericyte marker PDGFR-b. For astrocytes, a rabbit anti-GFAP antibody (Abeam). For microglia, a goat anti-Iba-1 (Abeam). Anti-goat or rabbit or mouse Cyanine5 (Invitrogen) antibodies were used as secondary antibodies.

[0102] Example 1.8. Statistical Analysis

[0103] Differences between groups were analyzed by one-way ANOVA followed by Tukey-Kramer posttest. Comparisons between data pairs were analyzed using a t test. Statistical significance was defined as / ? < 0.05.

[0104] Validation phase

[0105] Example 1.9. Mice

[0106] Male and female mice of six to eight weeks old wild type C57BL / 6 (Charles River Laboratories, strain #000664) and eight to ten weeks old NOD-SCID (NOD.Cg-Prkdcscld / J; Charles River Laboratories, strain #001303) were maintained in pathogen-free conditions in the animal facilities of the Institute of Biomedical Research of Murcia (IMIB). All animal procedures were approved and performed according to the guidelines set by the Institutional Animal Care and Use Committee of the IMIB (approved protocol A13210202).

[0107] Example 1.10. Cell isolation and culture

[0108] Primary brain PC (WT PC) from mice were isolated from mice according to the method of Oishi et al. (Oishi cl al . 2<>( )7 ) as described previously (Valdor cl al . 2< • 17. 2(> ] oj PCswereused from the 5thto 8thpassage and maintained Minimum Essential Medium Alpha (MEM-ci; Gibco, 15430584) supplemented with 20% fetal bovine serum (FBS, Cytiva, 12389802), 100 U / mL penicillin-streptomycin (Sigma), and 2 mM GlutaMax (Gibco, 35050061) at 37°C in 8.5% CO2.

[0109] Human glioma cell lines U87MG (U87), U251MG (U251), U373MG (U373), were purchased from European Collection for Authenticated Cell Cultures (ECACC) and were cultured in DMEM high glucose (Biowest) supplemented with 10% FBS (Biowest, REF), 1% penicillinstreptomycin (Sigma) and 1% L-glutamine (Sigma).

[0110] Patient-derived glioma stem cell (GSC) lines, kindly provided by Dr. Ander Metheu ( ii / mendi-l naite el al . 2< '22 ), were cultured in DMEM / F-12 (Biowest) supplemented by N2, B27 (Thermo Fisher Scientific), 100 U / mL penicillin, 100 mg / mL streptomycin, and growth factors (20 ng / mL basic FGF and 20 ng / mL EGF; Sigma- Aldrich). Lung (A427) and liver cancer (HepG2) cell lines were cultured in minimum essential medium Eagle (EMEM) with nonessential ammino acids (NEAA), 10% FBS, 1% penicillin-streptomycin and 1% sodium pyruvate. All cancer cells were maintained at 37°C and 8.5% CO2.

[0111] Dil labelling solution (Invitrogen, D3911) was used for cell tracking as described previously ( Molina el al . 2' '22. p 22).

[0112] Example 1.11. Synthetic peptides

[0113] Peptides P140 and PCt were assembled and purified as described i Page cl al . 2>)l I . Macri el al . 2o l4' ). Briefly, P140 peptide (IPP -201101; sequence 131-151 of the U1-70K protein phosphorylated at Serl40), as well as PCt (scramble version), were synthesized using classical N-(9-fluorenyl) methoxy carbonyl solid-phase chemistry and purified by reversed phase high- performance liquid chromatography (RP-HPLC). For labelling purposes, Alexa Fluor 488 Cys- P140 and Cys-PCt peptides were prepared, purified by HPLC and lyophilized in the dark ( Page cl al . 201 1 )

[0114] Example 1.12. Functional assays

[0115] Adhesion assay: GB cells (2*104) labelled with Dil solution were cocultured (1 :1) on a monolayer culture of PC pre-treated (1 h) with 10 pM or 20 pM P140 / PCt for 48 h. Cells were lysed after washing away non-adhered cells with media and remaining Dil fluorescence in the wells (belonging to the GB that adhered to PC) was measured at 488 nm (588-nm emission). Cell death assay: 8><104WT PCs were cultured in 24-well plates and incubated for 1 h with P140 or PCt (10 pM) before being cocultured (1:1) with Dil-labelled GB cells for different time points. At end points, dead cells were labelled with LIVE / DEAD Far Red cell stain (Invitrogen, L10120) and analyzed by flow cytometry using a BD LSR Fortessa X-20 flow cytometer (BD Bioscience).

[0116] Example 1.13. Transfections and reporter assay

[0117] All plasmid transfections were done using Lipofectamine 2000 (Invitrogen) in Opti-MEM Reduced Serum Media (Gibco, #51985-026). For CMA activity assay, WT PC (2>< 104) were transfected with the plasmid KFERQ-PA-mCherry 1 Koga el al . 2<) 1 1 ) Twenty -four hours post-transfection, cells treated for 1 h with Pl 40 or PCt and were exposed to 405 nm light to photoactivate PA-mCherry. Immediately afterwards, they were cocultured with GB cells at 1 : 1 ratio. Cells were fixed with 4% PFA after 48 h of coculture. For macroautophagy monitoring, 2* 104WT PC were transfected with the mCherry-GFP-LC3 plasmid ( Pankix el al.. 2<i( ). Twenty -four hours post-transfection, cells were treated for 1 h with P140 or PCt (10 pM) before being cocultured (1:1) with GB cells. Cells were fixed at different time points and lysosome inhibitors (LI, NH4CI 10 mM and Leupeptin 100 pM) were added in the last 6 h before fixing with 4% PFA. Changes in the numbers of lysosomes highlighted by the reporters were analyzed by fluorescence microscopy. Images were acquired with a Nikon Eclipse Ti microscope equipped with a 60* Plan Apo Vc objective (numerical aperture, 1.40) and a digital Sight DS- QiMc camera (Nikon) and 387 nm / 447 nm, 543 nm / 593 nm filter sets (Semrock), and the NIS- Elements AR software (Nikon). CMA activity was measured as the number of fluorescent puncta per cell. Macroautophay flux was measured as the number of fluorescent red and yellow (red+green) puncta per cell. Quantification was performed using ImageJ (NIH, United States). All determination were performed in at least three experiments.

[0118] Example 1.14. ELISA

[0119] PC (5* 104) were co-cultured with GB cells at 1 : 1 ratio in 96-well plates for 72 h. At end point, cell supernatants were collected and concentrated using Amicon Ultra centrifugal filters 10k (Millipore).

[0120] Mouse IL1-P (RyD Systems), IFNy (RyD Systems), SPARC (ABclonal), Lumican (Arigo), Vitamin D (Arigo) and AGT (Abeam) levels secreted by PC in the media was measured by sandwich ELISA with specific anti -mouse antibodies following the manufacturer’s recommendations. GB cell culture supernatant and concentrated cell culture media was used as negative controls.

[0121] Example 1.15. Immunofluorescence, immunohistochemistry, and microscopy

[0122] For immunofluorescence, WT PCs (2* 104) were cultured in 24-well plates and incubated for 1 h with P140 or PCt (10 pM) before being cocultured (1 : 1) with GB cells for 48 h. Lysosome inhibitors (LI, NH4CI 10 mM and Leupeptin 100 pM) were added 6h before being fixed with 4% PFA. Images were acquired with a Nikon Eclipse Ti microscope equipped with a 60* Plan Apo Vc objective (numerical aperture, 1.40) and a digital Sight DS-QiMc camera (Nikon) and 387 nm / 447 nm, 543 nm / 593 nm filter sets (Semrock), and the NIS-Elements AR software (Nikon). Fluorescence intensity was quantified per field, relative to the total image area and performed using ImageJ software (NIH, USA).

[0123] Mouse brains were paraffin embedded and processed by the Pathology facility (IMIB Pascual Parrilla), as described previously ( Molina cl al . Z<>22. Vaklor el al . 2<1 Three-micron thick serial sections were obtained from paraffin embedded samples using an automatic rotary microtome (ThermoFisher Scientific). For colorimetric immunolabeling, sections were incubated overnight at 4°C with mouse anti-STEM-121 (Takara, Y40410), goat anti-Iba-1 (Abeam, ab5076) and rat anti-CD68 (AbDserotec, MCA1957T) primary antibodies. Sections were finally incubated with the corresponding 3-3 'Diaminobenci dine (DAB) secondary antibodies (Vector Labs) and Mayer’s hematoxylin (Carlo Erba Reagents, LLG06272066) counterstained. Positive immunoreaction was identified as a dark-brown precipitated. An automatic digital slide scanner (Pannoramic MIDI II-3DHistech) and Quantitative Pathology & Bioimage Analysis Qupath-0.2.3 software were used for analysis of histological sections, and acquisition of images. Morphometric measurements and quantification of cells were also performed using ImageJ (NIH, United States) software.

[0124] For cryostat sections, brains were OCT embedded, and twenty -five-micron sections were obtained using a cryostat (ThermoFisher Scientific). For fluorescent labelling, we used the following antibodies: mouse anti-human STEM121 (1:1000; Takara, Y40410), goat antiplatelet derived growth factor receptor beta (PDGFRP; R&D Systems, BAF1042), goat anti- GFAP (Novus, NB100-53809), and goat anti-Iba-1 (Abeam, ab5076), rabbit anti-NeuN (Sigma, ABN78). Labelling was visualized by fluorescence microscopy using the corresponding secondary antibody conjugated to AlexaFluor488 (Invitrogen) or Cy5 (Invitrogen). Fluorescence samples were counterstained with DAPI (Invitrogen) prior to mounting with Dako fluorescent mounting medium (Dako). A TCS-SP8-MP-AOBS laser scanning spectral inverted Confocal Microscope (Leica Microsystems) was used to analyze the histological sections. Maximum-intensity projection of images was achieved with LAS X software (Leica Microsystems) and ImageJ software (NIH, USA).

[0125] Example 1.16. Flow cytometry analysis

[0126] Mononuclear cells from central draining lymph nodes of mice were isolated and labelled using specific antibodies for murine CD4, FoxP3, CTLA-4 (eBioscience) and PD-1 (Novus). Background nonspecific fluorescence was measured using control isotype antibodies. Labelled cells were analyzed by flow cytometry using a BD LSR Fortessa X-20 flow cytometer (BD Bioscience). All determination were performed in at least n = 4 mice per experimental group and three separate experiments.

[0127] Example 1.17. PC Exofucosylation

[0128] Murine PCs pretreated with Pl 40 or PCt (10 pM) for 48 h were modified by enzymatic exofucosylation as previously reported (Garcia-Bernal et al., 2020; Molina et al., 2022). Briefly, cells were resuspended at 2* 107 cells / mL in fucosyltransferase VII (FTVII) reaction buffer composed of Hanks Balanced Salt Solution (HBSS, Gibco) containing 30 pg / mL fucosyltransferase VII (FTVII; R&D Systems), 20 mM HEPES (Thermo Fisher Scientific), 0.1% human serum albumin (Grifols) and 1 mM guanosine 5'-diphospho-P-L-fucose sodium salt (GDP -fucose, Sigma Aldrich), and incubated for 60 min at 37°C and 5% CO2. Peptide concentration was maintained during exofucosylation incubations.

[0129] Example 1.18. Xenografts and Therapeutical Strategies

[0130] Cell pellets from human GB cells (U87, U251 or GSC) were grafted into C57BL / 6 (l><106 cells / mouse) and NOD-SCID (0.4x 106 cell / mouse) mice brains under stereotaxic conditions. After isoflurane anaesthesia, mice were placed in a mouse stereotaxic frame (RWD Life Science, RWD-68019) and a craniotomy was performed in the parietal cortex (1.5-mm from the midline and 1.5-mm lateral to bregma) using a microdrill (RWD Life Science, RWD- 78001). Cells were injected at a flow rate of 1 pL / min in the hippocampus (penetrating dorsoventrally from the brain pial surface 2.5 mm) using a 10 pL Hamilton 26 G syringe (Hamilton Company, #80330) mounted on a Stoelting QSI Quintessential Stereotaxic Injector (Stoelting Co., 53311). After injection, the needle was left in place for 2 min before slowly retracting and closing the wound. Between two- and three-weeks post-grafting, mice were treated with different therapeutical strategies to compare to those non-treated. To perform the cell therapy strategy, five mice were injected intravenously (0.25x106 cells per tail; 100 pl) once with exofucosylated PC pretreated with Pl 40 or PCt and compared to five untreated. Two weeks after therapy, mice were sacrificed, and brains were fixed in 4% buffered formalin (Panreac Quimica). To perform the in vivo peptide therapy, five mice were injected intravenously with four doses to different concentrations of P140 or PCt: 50 pg each dose per mouse (100 pl per tail of 2.5 mg / kg), or 25 pg (1.25 mg / kg) or 12.5 pg (0.6 mg / kg). The first two doses were consecutive, and the following doses were injected every 3 days. At 4th dose or one week after therapy, mice were sacrificed, and brains were fixed in 4% buffered formalin (Panreac Quimica). For peptide biodistribution, six mice were injected intravenously with Alexa Fluor488-labelled P140 or PCt (50 pg per mouse: 2.5 mg / kg; 100 pl per tail) and sacrificed after 24 h. Collected brains were fixed in 4% PFA in PBS. All described procedures were repeated three times.

[0131] Example 2. RESULTS

[0132] Discovery phase Example 2.1. The peptide 140 reduces GB-PC interactions required for GB proliferation and survival

[0133] PCs promote GB survival and proliferation through physical interaction enhancing the immunosuppressive function of PCs that prevent anti -tumor immune responses. We analyzed the GB cell proliferation and survival and the PCs-tumor cell interactions in presence or absence of two different concentrations of the peptide and compared to a control peptide and GB cells alone. Luciferase activity related to tumor cell proliferation and survival was measured in GB-U87 cell co-cultured with pretreated PC with or without (C) control peptide (pC) or peptide 140 (pl) at several concentrations and 1 hour previously to add Glioblastoma cells (Figure 1A). We also compared the effect of the peptides in GB-U87 cells both in the presence and in the absence of PC cells. We found that the effect of the inhibitor peptide significantly reduced the luciferase expression related to GB cell levels in the cocultures PCCGB, and the effect was dependent on the peptide concentration (Figure 1A), finding as the optimal concentration, 10 pM (Figure 1A, B).

[0134] To analyze the stable interactions between GB and PC, several GB cell lines stained with a fluorescent cell-tracker (dil) were added on a monolayer of pretreated PC with control or inhibitor peptide and co-cultured for 48 hours. The percentage of adhesion was analyzed related to levels of fluorescence that were normalized to control adhesion of control GB cells (Figure 1C). Our results corroborated the findings showing reduced GB proliferation in an optimal concentration of 10 pM compared to higher concentration of the peptide and controls. Our results revealed that the inhibitor peptide (pl) significantly reduced the stable cell-to-cell interactions between GB and PC (Figure ID), which promote tumor cell proliferation and survival [Valdor et al., 2019, PNAS],

[0135] In line with our previous results, we found that the GB cell survival was affected in presence of pretreated PCs with Pl 40 and compared to those nontreated control (negative CT) or treated with the control peptide (pCT) (Figure 1 E).

[0136] Example 2.2. Intravenous therapy with peptide 140 promotes tumor cell elimination

[0137] To determine if the P140 was also affecting the proliferation and survival of GB cells in vivo, GB mice [Molina et al, 2022, Front. Cell. Dev. Biol], were treated intravenously with a P140 or pCT therapy and using different Pl 40 doses to determine a dose-response (Figure 2A). After, 14 days of treatment, cells of a previously engrafted tumor (GB control) were hardly detected outside of the brain parenchyma in GB mice treated with the highest dose of Pl 40, (Figure 2B; 50 pg) and compared to those treated with pCT and GB control mice, which showed brain infiltration of tumor cells in choroid plexus and subpial vessels, and tumor masses in brain cortex around perivascular areas. The effect of P140 on the tumor cells resulted dose dependent, as mice treated with lower dose concentration showed an evident reduced tumor mass and remaining tumor cells close to blood vessels whereas, no significant differences were founded with the lowest dose of the peptide (Figures 2 B, C and D).

[0138] As we wanted to demonstrate that intravenously injected Pl 40 reached tumor niche, going through the blood brain barrier (BBB), GB-grafted mice were intravenously injected with Pl 40 labeled with Alexa 488 (P140AF488) and compared to those injected with control peptide (pCTAF488) (Figure 3), using the most efficient dose of P140 (50 pg per mouse). We found both peptides reached tumor areas of the brain cortex, being mainly accumulated in peritumoral areas (Figure 3 A) after 24 hours of inj ection. Peptides colocalized mainly in perivascular areas with pericytes (Figure 3 B) and in the rest of the brain parenchyma, hardly with astrocytes (Figure 3 C) and mainly with microglia cells (Figure 3 D). Importantly, we found that mice treated with P140 did not show phagocytic immune populations associated to the tumor, after the treatment (Figure 4). The expression of the microglia marker Iba-1 (Figure 4 A) and the macrophages activation marker CD68+(Figure 4 B) were significantly reduced compared to mice untreated or treated with the control peptide (Figure 4). Moreover, infiltration of different T cells populations associated to the tumor progression were reduced, hardly detecting remaining CD4+ cells without any evidence of infiltration of immunosuppressive cells presenting FOXP3 (Figure 5) and thus, showing only the presence of effector CD8+T cells against tumor cells.

[0139] Validation phase

[0140] Example 2.3. P140 prevents PC-tumor cell interactions with other types of cancer cells

[0141] As we wanted to elucidate if peptide might be also efficient to prevent interactions of tumor cells-PCs supporting tumor growth in other types of microvascularized cancers different to GB, we analysed the cell adhesion of PCs with lung (Figure 6A) and liver (Figure 6B) cancer cell lines. As expected, both cancer cell lines co-cultured with control peptide-pretreated PCs, presented high adhesion ability compared to control tumor cells. Importantly, both cancer cell lines showed significant reduction of their adhesion to peptidel40-pretreated PCs compared to controls, indicating Pl 40 on PCs prevents tumor cell interactions that favour tumor cell proliferation. Example 2.4. P140 does not inhibit PC CMA but prevents its GB-induced aberrantly upregulation

[0142] P140 had been shown to be able to inhibit the pathological CMA levels in specific immune cells, reducing their inflammatory and immunoactivating properties in different inflammatory diseases ( Page el al . 2<> I 1. Macri el al . 2(11 A Schall el al . 2( 22. Keinakuinai el al . 2022). We wanted to check if this was not occurring in PCs, as we previously had found, an opposite inflammatory phenotype that is able to eliminate tumor cells when CMA is ablated (Molina et al., 2022). As expected, the control peptide did not show any effect and P140 did not inhibit CMA activity in PCs. P140 just affected basal levels of CMA in PCs, in long kinetic of treatment after 48 hours of cell culture. Importantly, CMA levels in P140-pretreated PCs were enough restored in presence of GB cells and from early time kinetics (24 h) of cell co-culture, preventing the GB-induced aberrant CMA activity that occurs in GB -conditioned PCs, pretreated with control peptide (Figure 7A).

[0143] Example 2.5. The P140 effect on PCs in response to GB cells is specific on preventing aberrant CMA upregulation but not affect other types of autophagy

[0144] We wanted to verify that the prevention of the GB-induced aberrantly CMA in P140-pretreated PCs, was not a consequence of a blockage of macroautophagy activity, another type of autophagy also needed for cell homeostasis and shown to be impaired in specific immune cells in response to P140 ( Macri el al . 2o I 5 ) To assess the specificity of the peptide’s effect in the PC-GB cocultures, we used the mcherry-GFP-LC3 reporter to evaluate the macroautophagy activity in P140-pretreated PCs, at different time points. Pl 40 did not affect the LC3 flux in GB -conditioned PCs, and neither in basal levels in PCs alone (Figure 7B), indicating macroautophagy was not affected and Pl 40 effect was specific of preventing the aberrant CMA upregulation in PCs, in response to GB cells.

[0145] Example 2.6. P140 promotes an antitumoral and proinflammatory secretome in PCs

[0146] As we previously have found P140-pretreated PCs were able to prevent tumor cell adhesion and promote tumor cell elimination, we wanted to clarify if the P140 effect on these cells was resulting in PC turning into inflammatory cells with an effective secretome likely responsible of eliminating GB cells. Thus, we evaluated the secretion of proteins with antitumoral properties identified in previous studies from our lab (Valdor et al., 2019, Molina et al.2022). We found that P140-pretreated PCs increased significantly the secretion of SPARC, Lumican and vitamin D in response to GB cells (Figure 8 A-C). Moreover, the peptide treatment enhanced the secretion of IL 1 and IFNy in PCs against GB, promoting an antitumoral proinflammatory phenotype (Figure 8 DE). Importantly, our results also supported the prevention of the pro-tumor angiogenic function of PCs conditioned by GB, showing impaired increase of AGT secretion in P140-pretreated PCs, in response to GB cells (Figure 8 F).

[0147] Example 2.7. Intravenous administration of P140 prevents tumorigenesis, promotes inflammatory anti-tumor immune responses and is accumulated specifically in phagocytic cells including PCs

[0148] Once we established that the most effective dose of P140 was 50 pg per mouse, we wanted to evaluate its effect on tumorigenesis initiating cells of GB, patient-derived Glioma Stem Cells (GSCs) in a shorter treatment kinetic on an immunocompetent mouse model (Figure 9A). The intravenous administration of the peptide reduced the number of tumor cells and its proliferative capacity (Figure 9 B, C, D). Excitingly, we found that mice treated with P140 increased activated phagocytic immune populations in peritumoral areas, around corpus callosum and hippocampus (Figure 9 E-G). Besides, the control peptide treatment only showed tumor-associated immune populations. Pl 40 increased significantly the expression of the microglia marker Ibal and the proinflammatory cytokine IFNy in tumor surrounding areas compared to mice untreated or treated with the control peptide (Figure 9F). Furthermore, P140 increased the infiltration of CD68 positive cells in tumor surrounding areas, reducing those associated with the tumor (Figure 9 GH). Importantly and supporting the activation of brain anti-tumor immune responses by P140 treatment, we found purified CD4+ T cells from lymph nodes of mice xenografted with GSCs and treated with Pl 40, revealed by flow cytometry analysis compared to T cells from control mice, lower levels of 2 co-inhibitor receptors associated with suppression of T cell function in the tumor microenvironment: PD-1 and cytotoxic T lymphocyte-associated protein-4 (CTLA-4). Additionally, the levels of immunosuppressive T cells (Tregs) expressing FOXP3, were reduced after treatment (Figure 10).

[0149] As we wanted to demonstrate that intravenously injected Pl 40 reached tumor niche specifically, going through the blood brain barrier (BBB), GB-grafted mice were intravenously injected with P140 labelled with Alexa 488 (AF488-P140) and compared to those injected with control peptide (AF488-PCt) (Figure 11). We found both peptides reached tumor areas of the brain cortex, being the Pl 40, specifically accumulated in just peritumoral areas (Figure 11 A), after 24 hours of injection. Both peptides colocalized mainly in perivascular areas with phagocytic cells including PCs, which showed a higher uptake of P140 (Figure 11B). The control peptide was nonspecifically identified in the rest of the brain parenchyma, in all types of cells including also neurons (Figure 11C-E), whereas the P140 was hardly founded in astrocytes (Figure 11C) and primarily accumulated in microglia cells (Figure 11D).

[0150] Example 2.8. P140 impairs GB progression in an immunocompromised GB mouse model with just the innate immune response

[0151] We wanted to corroborate if one of the action mechanisms of the P140 in GB cancer through prevention and / or elimination of tumor cell interactions with PCs, was to make PC to become into inflammatory cells with ability to enhance the anti -turn or responses from the innate immune populations of the brain. Thus, Nodescid immunocompromised mice with nonfunctional T / B cells, were xenografted with human GSCs and treated intravenously with Pl 40 comparing to those treated with PCt. Excitingly, we found tumor clearance and hardly proliferating GSCs that are needed for tumorigenesis, in those mice that were treated with P140 and compared the treated with control (Figure 12). Our results indicated that tumor clearance and prevention of its progression can be leaded by just the innate immune responses without the need for the responses of T / B cells. Moreover, our results support the strong effect of P140 on PCs, boosting their effect as inflammatory cells with a toxic secretome for tumor cells.

[0152] Example 2.9. Intravenous administration of P140 pre-treated PCs promotes tumor clearance

[0153] As we had stablished the effects of P140 in brain PCs in vitro, we wanted to determine if these pre-treated PCs could also affect the proliferation and survival of GB cells in vivo. We xenografted immunocompetent C57BL / 6 mice orthotopically with GB cells (Molina et al., 2022) to later perform our cell therapy. Once the tumoral mass was formed, we intravenously injected the mice with PCs treated with P140 (P140-PC) or PCt (PCt-PC) (Figure 13A). After 14 days of the PC treatment, we analyzed the number of GB cells (STEM212+) in the brain and measured the tumor area. The GB mice injected with of PCt-PCs showed brain infiltration of tumor cells in choroid plexus and subpial vessels, and tumor masses in brain cortex around perivascular areas similar to control GB mice. Nevertheless, only some cells of a previously engrafted tumor were hardly detected outside of the brain parenchyma in GB mice treated with P140-PC (Figure 13B-D). The intravenous administration of peptide-pretreated PCs also modulated the activation of microglia and of phagocytic populations in the tumor areas and surroundings, as expected (Molina et al. 2022). Untreated GB control mice and those treated with PCt-PC presented tumor-associated Ibal microglia and it was scarcely associated with perivascular cells (Fig. 3E, F). However, P140-PCs activated the microglia in the tumor-surrounding areas of the thalamus and promoted the activation of perivascular areas (Figure 13E, F). Consistently, PCt- PCs treatment only showed phagocytic immune populations CD68+ in association with the tumor, as in controls (Figure 13G, H). In addition, the treatment with P140-PCs reduced the infdtration of these populations and they were only found in perivascular areas of the peritumoral regions (Figure 13G, H).

Claims

CLAIMS1. Peptide selected from the group consisting of SEQ ID NO: 1 or SEQ ID NO: 2, or a peptide having an identity of sequence of at least 95% with SEQ ID NO: 1 or SEQ ID NO: 2, for use in a method for the prevention and / or treatment of cancer.

2. Pharmaceutical composition comprising a peptide selected from the group consisting of SEQ ID NO: 1 or SEQ ID NO: 2, or a peptide having an identity of sequence of at least 95% with SEQ ID NO: 1 or SEQ ID NO: 2, and, optionally, pharmaceutically acceptable excipients or carriers, for use in a method for the prevention and / or treatment of cancer.

3. Peptide or pharmaceutical composition for use, according to claims 1 or 2, in a method for the prevention and / or treatment of cancer disease promoted by the interaction of pericytes and cancer cells, wherein the method comprises administering the peptide or pharmaceutical composition of claims 1 or 2 to prevent interactions between cancer cells and pericytes.

4. Peptide or pharmaceutical composition for use, according to any of the previous claims, in a method for the prevention and / or treatment of cancer, wherein the method comprises: i) pre-treating pericytes with the peptide and ii) administering the pre-treated pericytes or the secretome derived thereof to the patient.

5. Peptide or pharmaceutical composition for use, according to any of the previous claims, in the prevention and / or treatment of: Cerebral Nervous System tumours, pancreatic cancer, colon and bowel cancer, liver cancer, bone cancer, breast cancer, brain tumours, mouth cancer, lung cancer, melanoma or renal cancer.

6. Peptide or pharmaceutical composition for use, according to any of the previous claims, in the prevention and / or treatment of: Glioma, glioblastoma or paediatric gliomas.

7. Peptide or pharmaceutical composition for use, according to any of the previous claims, wherein at least one serine is phosphorylated and / or wherein the methionine is oxidised in the SEQ ID NO: 1 or SEQ ID NO: 2.

8. Peptide or pharmaceutical for use, according to any of the previous claims, wherein the serine at position 10 of SEQ ID NO: 1, or the serine at position 9 of SEQ ID NO: 2, is phosphorylated comprising a phosphoserine residue at said position.

9. Pharmaceutical composition, for use, according to any of the previous claims, wherein the pharmaceutical composition is administered at a dosage of from about 100 ng to about 5 mg, preferably from about 25 ng to 5 mg.

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