A tumor-affinity peptide targeting human epidermal growth factor receptor 2 (HER2)

Abstract

The present invention belongs to the field of biomedical engineering, and specifically relates to a tumor affinity peptide for human epidermal growth factor receptor 2 and its application, wherein the tumor affinity peptide includes 6 sequences such as Leu-Arg-Leu-Ser-Gly-Gly-Hyp-Gln. Pharmacodynamic experiments have shown that the polypeptides of the present invention can be used in cancer diagnosis and treatment. These high-affinity polypeptides can specifically bind to a variety of tumor cells. The high-affinity characteristics of the targeting peptide can be used for optical imaging and nuclear medicine imaging of malignant tumors. These high-affinity polypeptide monomers, polypeptide dimers or polypeptide polymers can be directly or indirectly coupled with fluorescent dyes as tumor-specific targeting molecular probes, which are expected to achieve the effect of accurately locating the tumor boundary, and can bring real-time performance to preoperative and intraoperative image navigation, with the advantage of improving surgical accuracy. This series of polypeptide monomers, dimers or polymers can also be coupled with radionuclides to detect malignant tumors in real time in vivo to achieve the purpose of disease diagnosis or treatment.

Description

Technical Field

[0001] The invention belongs to the field of biomedical engineering, and in particular relates to a tumor affinity peptide targeting human epidermal growth factor receptor 2. Background Art

[0002] Tumors have become the number one killer endangering human health, and their mortality rate continues to rise. Before cancer metastasizes to other organs, early detection of malignant lesions can allow for clear local treatment as early as possible, thereby achieving a very high survival rate. Therefore, early diagnosis and treatment of malignant tumors are crucial. For tumors, conventional imaging diagnostic techniques are mainly B-ultrasound, CT and MRI. These imaging diagnostic techniques achieve diagnostic results by showing functional changes in tissues and have good application value, but they still have certain deficiencies in differential diagnosis, systemic staging and early efficacy evaluation. In recent years, with the understanding and research of tumors and related disciplines, the focus of research has begun to shift to specific tumor diagnostic drugs targeting abnormally expressed targets in tumor cells for early diagnosis of tumors. Specific tumor diagnostic drugs targeting targets mainly bind specifically to tumor cells and have no binding to normal cells, thus achieving a highly selective and low-toxic diagnostic effect. At present, it is believed that targeted peptides are an ideal means of tumor targeted therapy, with the following advantages: 1) fast plasma clearance, high affinity and strong specificity; 2) good tissue penetration and can be taken up by tumor cells; 3) easy chemical synthesis and low immunogenicity, which can avoid the shortcomings of monoclonal antibody therapy.

[0003] Epidermal growth factor receptor (EGFR) is a giant transmembrane glycoprotein with a molecular weight of about 180 kDa. It has ligand-induced tyrosine protein kinase activity and is a member of the conserved receptor family ErbB. Other members of this family include HER2 / Neu / ErbB2, HER3 / ErbB3 and HER4 / ErbB4. The common characteristics of ErbB receptors are: containing an extracellular (EC) ligand binding region, a single transmembrane region composed of two repeated cysteine-rich regions, and intracellular sequences containing tyrosine protein kinases and autophosphorylation sites. When bound to a ligand, the receptor dimerizes, which is crucial for changing the high affinity state between the ligand and the receptor and for the receptor to transmit phosphorylation signals between molecules.

[0004] HER2, also known as c-erB2 (epidermal growth factor receptor 2), is composed of 922 adenines, 1382 cytosines, 1346 guanines and 880 thymines. The human gene is located on chromosome 17q21 and is a proto-oncogene. Its encoded product, HER2 protein, is a 185kD transmembrane protein, referred to as p185, consisting of 1255 amino acids, and positions 720-987 belong to the tyrosine kinase region. HER2 protein is a transmembrane protein with tyrosine protein kinase activity and is a member of the EGFR family. The protein consists of three parts: the extracellular ligand binding region, the single-chain transmembrane region and the intracellular protein tyrosine kinase region. Since no ligand that can directly bind to it has been found, the HER2 protein mainly binds to its respective ligands by forming heterodimers with other members of the family, including EGFR (HERl / erbBI), HER3 / erbB3, and HER4 / erbB4. HER2 protein is often the preferred partner of heterodimers, and its activity is often stronger than other heterodimers. When bound to the ligand, it activates the activity of tyrosine kinase mainly by causing receptor dimerization and autophosphorylation of the tyrosine kinase region in the cytoplasm. The signal transduction pathways mediated by HER2 protein mainly include Ras / Raf / mitogen-activated protein kinase (MAPK) pathway, phosphatidylinositol 3-hydroxykinase (PI3K) / Akt pathway, signal transduction and transcription activation (STAT) pathway and PLC pathway. HER-2 has limited expression in normal human tissues and organs, but its expression level is higher in positive tumors. Therefore, HER-2 receptor can become a target for tumor-specific imaging. Summary of the invention

[0005] The primary purpose of the present invention is to provide a tumor affinity peptide for human epidermal growth factor receptor 2, which can be used to diagnose tumors with high expression of HER2 receptor in vivo and can be used to prepare a new type of targeted drug carrier.

[0006] The second object of the present invention is to provide the use of the tumor affinity peptide mentioned above.

[0007] The technical solution adopted by the present invention to solve the technical problem is:

[0008] In the first aspect, the present invention protects a tumor affinity peptide targeting human epidermal growth factor receptor 2 (HER2), selected from any one of the following polypeptides:

[0009] YQGL-1: Leu-Arg-Leu-Ser-Gly-Gly-Hyp-Gln; Hyp represents hydroxyproline;

[0010] YQGL-2: D-Leu-Arg-D-Leu-Ser-Gly-Gly-Pro-Gln; D-Leu represents D-type Leu;

[0011] YQGL-3: Leu-D-Arg-Leu-Ser-Gly-Gly-Pro-Gln; D-Arg represents D-Arg;

[0012] YQGL-4: Leu-Homo-Arg-Leu-Ser-Gly-Gly-Pro-Glu; Homo-Arg represents homoarginine;

[0013] YQGL-5: D-Leu-D-Arg-Leu-Ser-Gly-Gly-Hyp-Glu; Hyp represents hydroxyproline, and D-Leu represents D-Leu;

[0014] YQGL-6: Ac-Lys-Gly-Gly-Gly-Leu-Arg-Leu-Ser-Gly-Gly-Hyp-Glu; Hyp represents hydroxyproline.

[0015] In a second aspect, the present invention also protects the use of the tumor affinity peptides described above in the preparation of tumor diagnostic reagents, preferably in the preparation of tumor diagnostic imaging agents, and further preferably in the preparation of tumor diagnostic imaging agents for precise positioning of tumor boundaries and intraoperative image navigation, as well as in radionuclide imaging.

[0016] The polypeptide compound described in the present invention can be specifically targeted to the tumor site, and has good uptake and retention at the tumor site, has a high target / non-target ratio, is suitable for use as a fluorescent tumor imaging agent and a radionuclide imaging agent, and can be used to prepare optical imaging drugs for intraoperative image navigation of tumors and precise positioning of tumor boundaries.

[0017] In a third aspect, the present invention also protects a modified polypeptide having the following general formula: MLG,

[0018] Wherein, M represents a photolabel or a metal chelator, and the metal chelator can complex with a radionuclide;

[0019] L is a linking group;

[0020] G is any one of the tumor affinity peptides YQGL-X targeting human epidermal growth factor receptor 2 (HER2) described in the present invention (X=any integer from 1 to 6).

[0021] As a preferred embodiment of the present invention, the optical marker is selected from organic chromophores, organic fluorophores, light absorbing compounds, light reflecting compounds, light scattering compounds and bioluminescent molecules.

[0022] When M is a photolabel, MLG is a fluorescent molecular imaging probe with excellent imaging properties, and its structure contains the polypeptide YQGL of the present invention for targeting tumors, a photolabel for optical imaging, and a linker L that increases the distance between the targeting polypeptide and the photolabel and regulates the pharmacokinetic properties in vivo.

[0023] The optical label is selected from the group consisting of compounds containing organic chromophores, organic fluorophores, light absorbing compounds, light reflecting compounds, light scattering compounds and bioluminescent molecules.

[0024] As a further preferred embodiment of the present invention, the organic fluorophore is a near-infrared fluorescent dye, preferably selected from the group consisting of near-infrared fluorescent dyes ICG-Der-02 (also known as MPA), IRDye800, Cy7.5, and Cy5.5; MPA is further preferred.

[0025] As a further preferred embodiment of the present application, the radioactive nuclide is selected from 99m Tc, 68Ga, 64Cu, 67Ga, 90Y, 111In or 177Lu, 125I.

[0026] As a further preferred embodiment of the present invention, the L is selected from azidopentanoic acid, propiolic acid, polyethylene glycol, 1,4,7-triazacyclononane-1,4,7-triacetic acid, 7-[(4-hydroxypropyl)methylene]-1,4,7-triazanonane-1,4-diacetic acid, 1,4,7,10-tetraazacyclotetraazacyclododecane-1,4,7,10-tetraacetic acid, mercaptoacetyl triglycine, MAG2, N3S, N2S2 ligands, diethyltriaminepentaacetic acid, 1,4-succinic acid, 5-aminopentanoic acid, polyethyleneimine, 6-hydrazinopyridine-3-carboxylic acid, benzyl bromoformate, N-(2-aminoacetic acid)maleimide or a combination thereof.

[0027] As further preferred embodiment of the present invention, L is selected from any one or more of 6-aminocaproic acid, PEG 4, PEG 6, HYNIC-PEG4 or HYNIC.

[0028] In a fourth aspect, the present invention also protects the use of the modified polypeptide described above in the preparation of tumor diagnostic reagents; preferably, the use in the preparation of tumor diagnostic imaging agents; further preferably, the use in the preparation of precise positioning of tumor boundaries and intraoperative image navigation imaging reagents or the preparation of radionuclide imaging reagents.

[0029] In a fifth aspect, the present invention also protects the use of the polypeptide described above in the preparation of tumor-targeted drug carriers.

[0030] The polypeptide described in the present invention can highly simulate the tumor targeting of HER-2 (epidermal growth factor receptor 2), efficiently bind to epidermal growth factor receptor 2 (HER2) to the tumor site, and has good aggregation and retention at the tumor site, has a high target and non-target ratio, is suitable for use as a fluorescent tumor imaging agent, and can be used to prepare optical imaging drugs for intraoperative image navigation of tumors and precise positioning of tumor boundaries.

[0031] The tumors of the present invention include breast cancer, colorectal cancer, liver cancer, cervical cancer, lung cancer, brain glioma, pancreatic cancer, prostate cancer, etc.

[0032] Beneficial Effects

[0033] The beneficial effects of the present invention are:

[0034] 1. The present invention has developed a series of new high-affinity peptides that simulate HER2 (epidermal growth factor receptor 2), which can be used to target epidermal growth factor receptor 2 (HER2). HER2 receptors are highly expressed in tumors, and based on the principle that YQGL-X (X=1-6) peptides specifically bind to HER2 receptors, they can be used for early diagnosis of tumors with high HER2 expression.

[0035] 2. These peptides are all low molecular weight peptides with low synthesis cost, and this series of short peptides introduces non-natural amino acids for modification, which greatly improves the stability of the peptides in vivo. By extending the half-life of the peptides to increase their circulation time in the body, the imaging probes are promoted to concentrate and stay in the tumor site, thereby obtaining better tumor imaging effects and making it more conducive to clinical promotion and application.

[0036] 3. These peptides are reported for the first time, with simple preparation methods and convenient access channels.

[0037] 4. YQGL-X (X=1-6) series peptides can specifically bind to tumor cells. In vivo optical imaging and results have confirmed that they have excellent imaging effects on a variety of tumors, including liver cancer, breast cancer, cervical cancer and colorectal cancer.

[0038] 5. The present invention utilizes the advantages of the near-infrared fluorescent dye MPA, which has a deeper penetration depth and weaker background tissue autofluorescence, and has good application prospects in fluorescence imaging and fluorescence-guided surgery.

[0039] 6. YQGL-X (X=1-6) polypeptide radioactive drugs can be used for the screening and early diagnosis of tumors, and can also be used for real-time non-destructive in-situ monitoring and treatment of early malignant tumors. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1-3 The structure of the targeting compound YQGL-1 ( Figure 1), HPLC analysis chart ( Figure 2 ) and MS( Figure 3 ).

[0041] Figure 4 Flow cytometry was used to detect the affinity of different fluorescent targeting compounds in SKBR3 cells.

[0042] Figure 5 This is the optical imaging of the fluorescent targeting compound MPA-YQGL-1 in breast cancer 4T1 tumor-bearing mice.

[0043] Figure 6 This is the optical imaging of the fluorescent targeting compound MPA-YQGL-2 in breast cancer MDA-MB-231 tumor-bearing mice.

[0044] Figure 7 This is the optical imaging of the fluorescent targeting compound MPA-YQGL-3 in breast cancer MCF7 tumor-bearing mice.

[0045] Figure 8 This is the optical imaging of the fluorescent targeting compound MPA-YQGL-4 in colorectal adenocarcinoma HT29 tumor-bearing mice.

[0046] Fig. 9 This is the optical imaging of the fluorescent targeting compound MPA-YQGL-5 in liver cancer A549 tumor-bearing mice.

[0047] Fig.10 This is the optical imaging of the fluorescent targeting compound MPA-YQGL-6 in cervical cancer Hela tumor-bearing mice. DETAILED DESCRIPTION

[0048] The present invention is further described in detail below with reference to the examples. The reagents or instruments used without indicating the manufacturer are all regarded as conventional products that can be purchased on the market.

[0049] Embodiment 1:

[0050] This Example 1 provides a method for preparing the polypeptide YQGL-1. The polypeptide is synthesized by a solid phase synthesis method. The specific synthesis method is as follows:

[0051] 1) Resin swelling

[0052] Weigh n equivalents of Rink Amide MBHA resin into a peptide synthesis tube, add dichloromethane (DCM) to swell for 30 minutes, remove the DCM solution, wash with DMF, and dry.

[0053] 2) Removal of Fmoc

[0054] Add 20% piperidine in DMF solution to the synthesis tube, deprotect for 5 min, repeat twice, and wash with DMF after the reaction.

[0055] 3) Coupling

[0056] Add 2n equivalents of amino acid, 2n equivalents of DIPEA, 2n equivalents of HCTU and DMF to the synthesis tube, shake and react for 1 hour, remove the reaction solution and wash with DMF, then add the method of step 2) to remove Fmoc, wash, and detect with ninhydrin.

[0057] 4) Add different amino acids in the sequence in sequence to perform various modifications in the same manner as in step 3. The amino acid residues involved can be L-type or D-type, proline (Pro) can be replaced by hydroxyproline (Hyp), arginine (Arg) can be replaced by homoarginine (homo-Arg), and alanine can be replaced by β-alanine.

[0058] 5) Lysis

[0059] The resin was blown dry with nitrogen, and a cutting solution (87.5% TFA + 5% thioanisole + 2.5% ethanedithiol + 2.5% phenol + 2.5% water) was added to the polypeptide synthesis tube. The ratio of the cutting solution volume to the resin was approximately 10 ml / g. After reacting for 2-3 hours, the filtrate was filtered out, a large amount of ether was added, and then centrifuged. The solid was washed three times with ether to obtain a crude polypeptide.

[0060] 6) Separation and purification

[0061] Reverse phase high performance liquid chromatography was used for purification, the chromatographic filler for purification was 10 μm reverse phase C18, the mobile phase system was 0.1% TFA / water solution 0.1% TFA / acetonitrile solution, the gradient system was used for elution, and the ultraviolet absorption of the polypeptide was measured by ultraviolet spectrophotometry for quantification. The results showed that the polypeptide was successfully synthesized and the purity was above 95%. The collected eluate was placed in a freeze dryer for concentration and freeze-dried into a white powder.

[0062] Example 2 Preparation of polypeptide YQGF-X (X = 2-6)

[0063] The tumor targeting peptide YQGL-2 was prepared according to the method of Example 1. The sequence of the peptide was D-Leu-Arg-D-Leu-Ser-Gly-Gly-Pro-Gln; wherein D-Leu represents D-type Leu; the polypeptide shown was confirmed by mass spectrometry [MH] - =824.94.

[0064] Tumor targeting peptide YQGL-3, the sequence is Leu-D-Arg-Leu-Ser-Gly-Gly-Pro-Gln; D-Arg represents D-Arg; the peptide shown, mass spectrometry confirmed [MH] - =825.14.

[0065] Tumor targeting peptide YQGL-4, the sequence is Leu-Homo-Arg-Leu-Ser-Gly-Gly-Pro-Glu; Homo-Arg represents homoarginine, mass spectrometry confirmed [MH] - =835.28.

[0066] Tumor targeting peptide YQGL-5, the sequence is D-Leu-D-Arg-Leu-Ser-Gly-Gly-Hyp-Glu; Hyp represents the polypeptide represented by hydroxyproline, D-Leu represents D-type Leu, [MH] - =840.94.

[0067] Tumor targeting peptide YQGL-6, the sequence of which is a polypeptide represented by Ac-Lys-Gly-Gly-Gly-Leu-Arg-Leu-Ser-Gly-Gly-Hyp-Glu, [MH] -1 =1183.32.

[0068] Example 3 Preparation of fluorescent targeting compound ICG-Der-02(MPA)-YQGF-1

[0069] ICG-DER-02 (also known as MPA) comes from an invention patent applied for by our research group in the early stage, with the authorized patent number: CN101440282.

[0070] (1) 0.02 mmol MPA was dissolved in 200 μL ultra-dry DMSO, and 3.7 mg 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 2.2 mg N-hydroxysuccinimide (EDCI / NHS) (molar ratio MPA:EDCI:NHS=1:1.5:1.5) were added. The mixture was reacted in the dark for 4 h to perform carboxyl activation reaction.

[0071] (2) Take 0.02 mmol of the solid phase synthesized peptide YQGF-1 (X=1-6) and 0.1 mmol of triethylamine and 200 μL of ultra-dry DMSO and add them to a 5 mL reaction bottle, and react for 10 min under nitrogen protection; add the solution in the above reaction (1) to the reaction solution in (2), and stir at room temperature for 12 h.

[0072] (3) After the reaction, the reaction solution was concentrated by freeze drying, then diluted with distilled water, and separated and purified by preparative liquid phase. The preparative liquid phase conditions were as follows: Agilent 1220 Infinity II series HPLC system equipped with Agilent ZORBAX SB-C18 semi-preparative column (9.4×250 mm, 5 um) was used, gradient elution was 60 minutes, flow rate was 2 mL / min, and mobile phase A was ultrapure water (0.01% TFA), and mobile phase B was acetonitrile (0.01% TFA). The elution gradient was set as: 95% A and 5% B at 0-5 minutes, 85% A and 15% B at 15 minutes, 70% A and 30% B at 30 minutes, 50% A and 50% B at 45 minutes, and 10% A and 90% B at 60 minutes. The green product finally obtained was confirmed to be the expected product ICG-DER-02-YQGL-1 by analytical HPLC and ESI-MS mass spectrometry, see Figure 1-3 In the above preparation process, the YQGL-1 polypeptide used in the step is replaced by the solid-phase synthesized YQGL-X (X=2, 3, 4, 5, 6) polypeptide to obtain various other polypeptide compounds ICG-DER-02-YQGL-2, ICG-DER-02-YQGL-3, MPA-YQGL-4, MPA-YQGL-5, and MPA-YQGL-5 with tumor-targeting optical imaging function.

[0073] Example 4 Affinity of the compound MPA-YQGL-X (X=1-6) prepared for SKBR3 cells

[0074] (1) First, prepare and lay out a 12-well plate, digest the cells that are in good growth condition and free of bacteria, count them using the counting plate counting method, add the same amount of cells to each well of the 12-well plate, and then place it in a cell culture incubator at 37°C and 5% CO2 for 24 hours.

[0075] (2) After the cells have grown for 24 h, the culture medium in the 12-well plate was discarded and 500 μL of fresh culture medium without serum was added. Different groups were set up: blank group Control, single dye group MPA, and peptide group. 5 μL of MPA and 5 μL of peptide probe were added respectively, with an initial concentration of 500 μM. The final concentration in the well plate was 5 μM, and then the cells were incubated in the incubator for 2 h.

[0076] (3) Sample treatment before flow cytometry: discard the old culture medium in the well plate, digest with 0.05% trypsin, add culture medium containing 10% fetal bovine serum to resuspend, transfer the cell suspension to a 1.5 mL EP tube, centrifuge at 1200 rpm for 5 min, wash three times with 500 μL PBS buffer (pH 7.2), and finally add 500 μL PBS buffer (pH 7.2) to resuspend for later use.

[0077] (4) Determination of cell fluorescence intensity by flow cytometry: Set the flow cytometer parameters, the flow rate to medium flow rate, and the cell injection volume to 40,000 cells. Load the sample and measure the fluorescence intensity of each group, as well as the fluorescence intensity relative to the control group and the single dye group.

[0078] (5) Data processing: FlowJo 7.0 software was used to generate peak graphs of the raw data and calculate the mean fluorescence intensity (MFI). GraphPad Prism software was used to quantitatively plot the mean fluorescence intensity and perform data difference analysis.

[0079] When the probe has a strong affinity with the receptor on the cell, the average fluorescence intensity of the cell detected by flow cytometry is high. Figure 4 The results of in vitro affinity experiments showed that after the probes of MPA-YQGL-X (X=1-6) with the same concentration were incubated with SKBR3 cells with high expression of HER2, the YQGL-1 of the present invention had the strongest affinity with SKBR3, but YQGL-2, YQGL-3, YQGL-4, YQGL-5, and YQGL-6 also had obvious affinity compared with the blank control group.

[0080] Optical imaging of the compound MPA-YQGL-1 prepared in Example 5 in breast cancer 4T1 tumor-bearing mice

[0081] The compound MPA-YQGL-1 prepared in Example 3 was formulated into a physiological saline solution (1 mg / mL), and 15 μL of the drug MPA-YQGL-1 solution was injected into three breast cancer 4T1 tumor-bearing nude mice (weighing about 20 grams) through the tail vein, and optical signal collection was performed at 0.5h, 1h, 2h, 4h, 6h and 12h after administration. The distribution of the probe in the mouse body and the enrichment in the tumor area were observed. The imaging results of the compound MPA-YQGL-2 in the three tumor-bearing nude mice were basically consistent. From the imaging image at 1h, it can be seen that the probe has been clearly aggregated in the tumor, and the outline of the tumor edge is clear. The probe is still retained in the tumor until 12h. The imaging results are as follows. Figure 5 Among them, the probe was most enriched in the tumor site at 2 hours, while the uptake and clearance in other background organs was faster. From the signal of the bladder, it can be inferred that this probe is mainly metabolized by the kidney.

[0082] Optical imaging of the compound MPA-YQGL-2 prepared in Example 6 in breast cancer MDA-MB-231 tumor-bearing mice

[0083] The compound MPA-YQGL-2 prepared in Example 3 was formulated into a physiological saline solution (1 mg / mL), and 15 μL of the drug MPA-YQGL-2 solution was injected into three breast cancer MDA-MB-231 tumor-bearing nude mice (weighing about 20 grams) through the tail vein, and optical signal collection was performed at 0.5h, 1h, 2h, 4h, 6h and 12h after administration. The distribution of the probe in the mouse body and the enrichment in the tumor area were observed. The imaging results of the compound MPA-YQGL-2 in the three tumor-bearing nude mice were basically consistent. From the imaging image at 1h, it can be seen that the probe has been clearly aggregated in the tumor, and the outline of the tumor edge is clear. The probe is still retained in the tumor until 12h. The imaging results are as follows Figure 6 Among them, the probe was most enriched in the tumor site at 2 hours, while the uptake and clearance in other background organs was faster. From the signal of the bladder, it can be inferred that this probe is mainly metabolized by the kidney.

[0084] Optical imaging of the compound MPA-YQGL-3 prepared in Example 7 in breast cancer MCF7 tumor-bearing mice

[0085] The compound MPA-YQGL-3 prepared in Example 3 was formulated into a physiological saline solution (1 mg / mL), and 15 μL of the drug MPA-YQGL-3 solution was injected into three nude mice bearing MCF7 breast cancer (weighing about 20 grams) through the tail vein, and optical signal collection was performed at 0.5 h, 1 h, 2 h, 4 h, 6 h and 12 h after administration. The distribution of the probe in the mouse body and the enrichment in the tumor area were observed. The imaging results of the compound MPA-YQGL-3 in the three tumor-bearing nude mice were basically consistent. From the imaging image at 1 h, it can be seen that the probe has been clearly aggregated in the tumor, and the outline of the tumor edge is clear. The probe is still retained in the tumor until 12 h. The imaging results are shown in the figure. Figure 7 Among them, the probe was most enriched in the tumor site at 2 hours, while the uptake and clearance in other background organs was faster. From the signal of the bladder, it can be inferred that this probe is mainly metabolized by the kidney.

[0086] Optical imaging of the compound MPA-YQGL-4 prepared in Example 8 in mice bearing colorectal adenocarcinoma HT29

[0087] The compound MPA-YQGL-4 prepared in Example 3 was formulated into a physiological saline solution (1 mg / ml), and 15 μL of the drug MPA-YQGL-4 solution was injected into three colorectal adenocarcinoma HT29 tumor-bearing nude mice (weighing about 20 grams) through the tail vein, and optical signal collection was performed at 0.5h, 1h, 2h, 4h, 6h and 12h after administration. The distribution of the probe in the mouse body and the enrichment in the tumor area were observed. The imaging results of the compound MPA-YQGL-4 in the three tumor-bearing nude mice were basically consistent. From the imaging image at 1h, it can be seen that the probe has been obviously aggregated in the tumor, and the outline of the tumor edge is clear. The probe is still retained in the tumor until 12h. The imaging results are as follows: Figure 8 Among them, the probe was most enriched in the tumor site at 2 hours, while the uptake and clearance in other background organs was faster. From the signal of the bladder, it can be inferred that this probe is mainly metabolized by the kidney.

[0088] Optical imaging of the compound MPA-YQGL-5 prepared in Example 9 in mice bearing liver cancer A549

[0089] The compound MPA-YQGL-5 prepared in Example 3 was formulated into a physiological saline solution (1 mg / ml), and 15 μL of the drug MPA-YQGL-5 solution was injected into three nude mice bearing liver cancer A549 (weighing about 20 grams) through the tail vein, and optical signal collection was performed at 0.5 h, 1 h, 2 h, 4 h, 6 h and 12 h after administration. The distribution of the probe in the mouse body and the enrichment in the tumor area were observed. The imaging results of the compound MPA-YQGL-5 in the three tumor-bearing nude mice were basically consistent. From the imaging image at 1 h, it can be seen that the probe has been clearly aggregated in the tumor, and the outline of the tumor edge is clear. The probe is still retained in the tumor until 12 h. The imaging results are as follows: Fig. 9 Among them, the probe was most enriched in the tumor site at 2 hours, while the uptake and clearance in other background organs was faster. From the signal of the bladder, it can be inferred that this probe is mainly metabolized by the kidney.

[0090] Optical imaging of the compound MPA-YQGL-6 prepared in Example 10 in cervical cancer Hela tumor-bearing mice

[0091] The compound MPA-YQGL-6 prepared in Example 3 was formulated into a physiological saline solution (1 mg / ml), and 15 μL of the drug MPA-YQGL-6 solution was injected into three cervical cancer Hela tumor-bearing nude mice (weighing about 20 grams) through the tail vein, and optical signal collection was performed at 0.5h, 1h, 2h, 4h, 6h and 12h after administration. The distribution of the probe in the mouse body and the enrichment in the tumor area were observed. The imaging results of the compound MPA-YQGL-6 in the three tumor-bearing nude mice were basically consistent. From the imaging image at 1h, it can be seen that the probe has been clearly aggregated in the tumor, and the outline of the tumor edge is clear. The probe is still retained in the tumor until 12h. The imaging results are as follows. Fig.10 Among them, the probe was most enriched in the tumor site at 2 hours, while the uptake and clearance in other background organs was faster. From the signal of the bladder, it can be inferred that this probe is mainly metabolized by the kidney.

[0092] The protection content of the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the inventive concept, changes and advantages that can be thought of by those skilled in the art are included in the present invention and are protected by the attached claims.

Claims

1. A tumor affinity peptide selected from any one of the following polypeptides: YQGL-1: Leu-Arg-Leu-Ser-Gly-Gly-Hyp-Gln; Hyp represents hydroxyproline; YQGL-2: D-Leu-Arg-D-Leu-Ser-Gly-Gly-Pro-Gln; D-Leu represents D-type Leu; YQGL-3: Leu-D-Arg-Leu-Ser-Gly-Gly-Pro-Gln; D-Arg represents D-Arg; YQGL-4: Leu-Homo-Arg-Leu-Ser-Gly-Gly-Pro-Glu; Homo-Arg represents homoarginine; YQGL-5; D-Leu-D-Arg-Leu-Ser-Gly-Gly-Hyp-Glu; Hyp represents hydroxyproline, and D-Leu represents D-Leu; YQGL-6: Ac-Lys-Gly-Gly-Gly-Leu-Arg-Leu-Ser-Gly-Gly-Hyp-Glu; Hyp represents hydroxyproline.

2. Use of the tumor affinity peptide according to claim 1 in the preparation of tumor fluorescence imaging or radioactive imaging reagents, wherein the tumor is breast cancer, colorectal cancer, liver cancer or cervical cancer.

3. Use of the tumor affinity peptide according to claim 1 in the preparation of a tumor-targeted drug carrier, wherein the tumor is breast cancer, colorectal cancer, liver cancer or cervical cancer.

4. A modified polypeptide, characterized in that With the following general formula: ML-YQGL-X, or M-YQGL-X, Wherein, M represents photolabeling or radionuclide labeling; The middle L is a connecting group; YQGL-X is any polypeptide according to claim 1, and X is selected from any integer between 1 and 6.

5. The modified polypeptide according to claim 4, characterized in that The optical marker is selected from light absorbing compounds, light reflecting compounds, light scattering compounds and / or bioluminescent molecules.

6. The modified polypeptide according to claim 5, characterized in that The light absorbing compound is an organic chromophore or an organic fluorophore.

7. The modified polypeptide according to claim 5, characterized in that The optical marker is selected from near-infrared fluorescent dyes MPA, IRDye800, Cy7.5, and Cy5.

5.

8. The modified polypeptide according to claim 4, characterized in that The radionuclide is selected from 99m Tc, 68 Ga, 64 Cu, 67 Ga, 90 Y, 111 In or 177 Lu, 125 I.

9. The modified polypeptide according to claim 4, characterized in that The L is selected from azidopentanoic acid, propiolic acid, polyethylene glycol, 1,4,7-triazacyclononane-1,4,7-triacetic acid, 7-[(4-hydroxypropyl)methylene]-1,4,7-triazanonane-1,4-diacetic acid, 1,4,7,10-tetraazacyclotetraazacyclododecane-1,4,7,10-tetraacetic acid, mercaptoacetyl triglycine, MAG2, N3S, N2S2 ligands, diethyltriaminepentaacetic acid, 1,4-succinic acid, 5-aminopentanoic acid, polyethyleneimine, 6-hydrazinopyridine-3-carboxylic acid, benzyl bromoformate, N-(2-aminoacetic acid)maleimide or a combination thereof.

10. The modified polypeptide according to claim 4, characterized in that The L is selected from any one or more of 6-aminocaproic acid, PEG 4, PEG 6, HYNIC-PEG4 or HYNIC.

11. Use of the modified polypeptide according to any one of claims 4 to 10 in the preparation of a tumor tracing reagent, wherein the tumor is breast cancer, colorectal cancer, liver cancer or cervical cancer.

12. The use according to claim 11, characterized in that: The reagent is a fluorescent imaging or radioactive imaging reagent for a tumor, and the tumor is breast cancer, colorectal cancer, liver cancer or cervical cancer.

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