A tumor-targeting typhoid toxin B subunit mimetic peptide and its application

Abstract

The present invention discloses a tumor-targeting typhoid toxin B subunit mimetic peptide and its application. The typhoid toxin B subunit mimetic peptide is selected from any one of the six polypeptides YQPB-1: COOH-Thr-Gly-Ser-Gly-Asn-Ala-Asn-Val-NH2. The application of the typhoid toxin B subunit mimetic peptide or its dimer and multimer described in the present invention in the preparation of diagnostic reagents or tumor therapeutic drugs targeting tumors. The present invention has developed a series of new mimetic peptides that simulate the typhoid toxin B subunit (PltB) secreted by Salmonella typhi. The YQPB-X series of mimetic peptides can specifically bind to tumor cells with high expression of gangliosides. In vivo optical imaging and results have confirmed that they have excellent imaging results for various tumors such as neuroblastoma, non-small cell lung cancer, melanoma, breast cancer and osteosarcoma.

Description

Technical Field

[0001] The invention belongs to the field of biomedical engineering, and in particular relates to a tumor-targeting typhoid toxin B subunit mimetic peptide and an application thereof. Background Art

[0002] Cancer is a global public health challenge that seriously endangers human health. According to the relevant data released by GLOBOCAN in December 2021, there will be 19 million new cases of cancer and 9.96 million cancer deaths in the world in 2021. In recent years, malignant tumors have become the leading cause of death among urban residents in my country. The fight against cancer by all mankind has entered the critical stage. However, it is difficult to overcome advanced malignant tumors with the current medical level, and early detection and treatment are still the most effective means of treating malignant tumors. Therefore, early diagnosis of tumors is of great significance for improving the survival rate of patients. The conventional imaging technologies currently used for tumor diagnosis are mainly X-CT, nuclear magnetic resonance, and ultrasound diagnosis. Among them, molecular probes, as powerful tools for analytical sensing and optical imaging, can directly visualize biological analytes at the molecular level and provide useful information for complex biological structures and processes. The basic imaging principle of molecular probes is to inject the prepared fluorescent probes into living tissues, so that the target interacts with the molecular probe, and then detect the information emitted by the molecular probe with a suitable imaging system. With the help of molecular probes targeting tumors, early screening and early diagnosis of tumors can be achieved.

[0003] Surgical treatment is one of the means of tumor treatment. Patients have a better prognosis after surgical resection. However, the precise positioning of tumor boundaries has always been a scientific research problem that needs to be overcome. Providing surgical boundaries to surgeons to completely remove the tumor can reduce the possibility of postoperative recurrence in patients. However, the surgical navigation imaging agents currently approved by the FDA for clinical use have low sensitivity and weak specificity, such as the imaging agent indocyanine green used for liver cancer surgical navigation, which is difficult to meet clinical needs. Molecular probes targeting tumors have the advantages of strong specificity and high sensitivity, providing hope for the accurate positioning of tumor boundaries.

[0004] Salmonella serotype Typhi (S. Typhi) is the cause of typhoid fever, which kills more than 200,000 people each year. Unlike other Salmonella serotypes, which usually cause self-limited gastroenteritis, S. Typhi causes a systemic, life-threatening illness. S. Typhi encodes typhoid toxin, which is composed of a catalytic A subunit and a linking pentameric B subunit, including cholera toxin, pertussis toxin, Shiga toxin, and Escherichia coli subtilisin. A2B5 toxin is composed of two catalytic A subunits (PltA and CdtB) and a linking pentameric B subunit (PltB). PltB can bind to a family of gangliosides on the surface of cancer cells, which are expressed on a variety of cancer cells. Peptides that mimic the B subunit of typhoid toxin can target gangliosides on cancer cells, enabling early diagnosis of tumors and intraoperative navigation. Summary of the invention

[0005] The primary purpose of the present invention is to provide a tumor-targeting typhoid toxin mimetic peptide and its sequence. This series of polypeptides can bind to tumor cells with high expression of gangliosides to achieve targeted tumor lesions.

[0006] Another object of the present invention is to provide a fluorescent probe of a typhoid toxin-mimicking peptide targeting a tumor and a preparation method thereof;

[0007] Another object of the present invention is to provide a radionuclide probe of a typhoid toxin-mimicking peptide targeting a tumor and a method for preparing the same.

[0008] Another object of the present invention is to provide applications of several of the polypeptides and fluorescent and radionuclide probes.

[0009] The purpose of the present invention can be achieved through the following technical solutions:

[0010] The tumor-targeting typhoid toxin B subunit mimetic peptide is selected from any one of the following polypeptides:

[0011] YQPB-1: COOH-Thr-Gly-Ser-Gly-Asn-Ala-Asn-Val-NH 2 (SEQ ID NO.1),

[0012] YQPB-2: COOH-Thr-Gly-Ser-Gly-Cys-Ala-Asn-Val-NH 2 (SEQ ID NO.2),

[0013] YQPB-3: COOH-Thr-Gly-Ser-Gly-Asn-His-Asn-Val-NH 2 (SEQ ID NO.3),

[0014] YQPB-4: COOH-Thr-Gly-Ser-Gly-Asn-Ala-Asn-Val-NH 2 (SEQ ID NO.4),

[0015] YQPB-5: COOH-Thr-Gly-Ser-Gly-Tyr-Ala-Asn-Val-NH 2 (SEQ ID NO.5),

[0016] YQPB-6: COOH-Thr-Gly-Ser-Gly-Phe-Ala-Asn-Val-NH 2 (SEQ ID NO.6).

[0017] The application of the typhoid toxin B subunit mimetic peptide of the present invention in the preparation of a diagnostic reagent targeting a tumor is preferably used in the preparation of a tumor diagnostic imaging agent; further preferably used in the preparation of a precise positioning of the tumor boundary or a surgical navigation imaging agent or a radionuclide imaging agent. The tumor is a tumor expressing gangliosides, preferably neuroblastoma, retinoblastoma, melanoma, sarcoma, brain tumor, breast cancer, liver cancer, and non-small cell lung cancer.

[0018] A modified polypeptide compound with targeted tumor imaging function has the following general formula:

[0019] ML-YQPB-X

[0020] Wherein, M represents a light label or a radionuclide label; L represents a linking group;

[0021] YQPB-X is any one of the typhoid toxin B subunit mimetic peptides described in the present invention.

[0022] As a preferred embodiment of the present invention, the optical marker M described in the present invention is selected from an organic chromophore, an organic fluorophore, a light absorbing compound, a light reflecting compound, a light scattering compound or a bioluminescent molecule.

[0023] As a preferred embodiment of the present invention, the radionuclide label M is selected from 99m Tc, 68 Ga, 64 Cu, 67 Ga, 90 Y, 111 In or 177 Lu, 125 I.

[0024] As a preferred embodiment of the present invention, the L is selected from 6-aminocaproic acid, azidopentanoic acid, propiolic acid, polyethylene glycol, 1,4,7-triazacyclopentane-1,4,7-triacetic acid, 7-[(4-hydroxypropyl)methylene]-1,4,7-triazanonane-1,4-diacetic acid, 1,4,7,10-tetraazacyclododecane-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-aminocaproic acid)maleimide, HYNIC-PEG4, HYNIC or a combination thereof; preferably any one or more of 6-aminocaproic acid, PEG 4, PEG 6, HYNIC-PEG4 or HYNIC.

[0025] A near-infrared fluorescent imaging probe is the tumor-targeting typhoid toxin B subunit mimetic peptide labeled with a near-infrared fluorescent dye, wherein the near-infrared fluorescent dye is preferably MPA, IRDye800, Cy7.5, or Cy5.5.

[0026] A radionuclide probe is a radionuclide-labeled tumor-targeting typhoid toxin B subunit mimetic peptide of the present invention.

[0027] As a preferred embodiment of the present invention, the radionuclide probe is a hydrogen ortho-position of the phenolic hydroxyl group of tyrosine in the tumor-targeting typhoid toxin B subunit mimetic peptide of the present invention labeled with radioactive iodine or fluorine.

[0028] As a preferred embodiment of the present invention, the radioactive probe includes the tumor-targeting typhoid toxin B subunit mimetic peptide, a linking group, a radionuclide ligand, a bifunctional chelator for radionuclide labeling, and a radionuclide.

[0029] As a preferred embodiment of the present invention, the bifunctional chelating agent for radionuclide labeling is selected from HYNIC, DOTA, NOTA or DTPA.

[0030] The near-infrared fluorescence imaging probe and the radionuclide probe of the present invention are used in the preparation of imaging agents for tumor diagnosis and intraoperative navigation; preferably, they are used in the preparation of imaging agents for tumor diagnosis or intraoperative navigation, and further preferably, they are used in the preparation of imaging agents for precise positioning of tumor boundaries or surgical navigation or radionuclide imaging agents.

[0031] The tumor is a tumor expressing ganglioside, preferably neuroblastoma, retinoblastoma, melanoma, sarcoma, brain tumor, breast cancer, liver cancer, and non-small cell lung cancer.

[0032] The polypeptide described in the present invention highly simulates the typhoid toxin B subunit (PltB), has a good tumor targeting effect, can efficiently bind to the gangliosides on the cell membrane of tumor cells after entering the body, has good aggregation and retention at the tumor site, has a high target and non-target ratio, is suitable for being prepared into a fluorescent imaging agent, and is used as an optical imaging agent for precise positioning of tumor boundaries and an imaging agent for intraoperative navigation in tumor surgery.

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

[0034] 1. The present invention has developed a series of novel high-affinity peptides simulating typhoid toxin B subunit (PltB), which can be used to target gangliosides. Gangliosides are highly expressed on the cell membranes of various tumors such as neuroblastoma, retinoblastoma, melanoma, sarcoma, brain tumor, breast cancer, liver cancer, non-small cell lung cancer, etc. Based on the principle of YQPB-X (X=1-6) polypeptide binding to gangliosides, early diagnosis and intraoperative navigation of various tumors such as neuroblastoma, retinoblastoma, melanoma, sarcoma, brain tumor, breast cancer, liver cancer, non-small cell lung cancer, etc. can be achieved.

[0035] 2. The peptides in the YQPB-X series are all low molecular weight peptides. The short peptides in this series are composed of natural amino acids, and the raw materials are easily available and the synthesis cost is cheap. By extending the half-life of the peptide, the circulation time of the peptide in the body is increased, and the imaging probe is promoted to gather and stay in the tumor site, thereby obtaining a better tumor imaging effect, which is conducive to the promotion of clinical application.

[0036] 3. The polypeptide sequences provided in the present invention are all reported for the first time, the synthesis method is simple, and the acquisition channels are convenient.

[0037] 4. The peptides of the YQPB-X series have excellent imaging effects on a variety of tumors, including neuroblastoma, retinoblastoma, melanoma, sarcoma, brain tumor, breast cancer, liver cancer and non-small cell lung cancer.

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

[0039] 6.YQPB-X series peptides can be prepared into radioactive drugs for the screening and early diagnosis of tumors, and can also be used for real-time non-invasive in situ monitoring of early malignant tumors and treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Flow cytometry was used to detect the affinity of different near-infrared fluorescent probes to neuroblastoma cells SK-N-SH.

[0041] Figure 2This is the optical imaging of the near-infrared fluorescent probe MPA-YQPB-1 in nude mice bearing neuroblastoma SK-N-SH tumors.

[0042] Figure 3 This is the optical imaging of the near-infrared fluorescent probe MPA-YQPB-2 in nude mice bearing breast cancer MCF-7 tumor.

[0043] Figure 4 This is the optical imaging of the near-infrared fluorescent probe MPA-YQPB-3 in nude mice bearing non-small cell lung cancer A549 tumor.

[0044] Figure 5 This is the optical imaging of the near-infrared fluorescent probe MPA-YQPB-4 in nude mice bearing HepG2 liver cancer.

[0045] Figure 6 Radionuclide probe 99m Optical imaging of Tc-HYNIC-Aca-YQPB-1 in nude mice bearing breast cancer 4T1 tumor. DETAILED DESCRIPTION

[0046] The present invention is further described below by specific examples and application examples: the chemical substances used in the synthesis steps are all existing substances or commercially available products. The polypeptides involved in each example were commissioned to Hangzhou Gutuo Biotechnology Co., Ltd. for synthesis.

[0047] Example 1 takes polypeptide YQPB-1 as an example and comprises the following steps:

[0048] (1) Resin swelling

[0049] Add a certain amount of Rink Amide MBHA resin to the reaction column, then add an appropriate amount of dichloromethane (DCM), and gently blow nitrogen for 10-30 minutes to allow the resin to fully swell. Drain the dichloromethane solution, then wash with dimethylformamide (DMF) three times and drain.

[0050] (2) Removal of Fmoc

[0051] A 20% DMF solution of piperidine was added to the reaction column, and the deprotection was performed once every 5 minutes and once every 8 minutes. After the reaction was completed, the resin was washed three times with DMF, DCM, and DMF, respectively.

[0052] (3) Coupling

[0053] Accurately weigh 3 times the molar number of the feed resin Fmoc-Thr-OH and O-benzotriazole-tetramethyluronium hexafluorophosphate (HBTU), completely dissolve in DMF, add N,N-diisopropylethylamine (DIPEA) to activate the carboxyl group, and then add the solution to the reaction column for reaction. After 30 minutes of reaction, wash with DMF, DCM, and DMF three times in sequence, then drain the solvent, take a small amount of resin and add one drop of 6% ninhydrin / ethanol solution and 80% phenol / ethanol solution for detection. If the condensation is complete and there is no free amino group, the solution will be colorless or light yellow; otherwise, the resin or solution will turn blue or reddish brown, indicating that the reaction is incomplete. After the reaction is completed, wash with DCM, DCM, and DMF three times respectively. Repeat the above operation, and couple other amino acids in sequence until the last amino acid Fmoc-Val-OH is coupled, wash the obtained peptidyl resin with methanol, and dry it in a vacuum drying oven.

[0054] (4) Cracking A

[0055] Get 120mL of lysate (87.5% trifluoroacetic acid + 5% thioanisole + 2.5% ethanedithiol + 2.5% phenol + 2.5% water) and add to resin, shake 2h under low temperature, then separate lysate from resin with sand core funnel, retain filtrate. Slowly add filtrate dropwise to ice anhydrous ether, after dropwise addition, natural sedimentation 30min. Then centrifugal solid, wash solid three times with ether, after gained precipitation is dried, obtain dry powder crude product.

[0056] (5) Purification

[0057] The purification was carried out by high performance liquid chromatography, the chromatographic filler for purification was a 10 μm C18 preparative column, the mobile phase system was 0.1% TFA / water solution-0.1% TFA / acetonitrile solution, gradient elution and cyclic injection purification were adopted, the crude product solution was loaded on the chromatographic column, the mobile phase elution was started, the main peak was collected and the acetonitrile was evaporated to obtain the target polypeptide concentrate, which was then freeze-dried to obtain the target polypeptide YQPB-1, and finally the mass-to-charge ratio was measured to determine the molecular weight [MH] - =719.

[0058] Example 2 Preparation of polypeptide YQPB-X (X = 2-6)

[0059] The typhoid toxin mimetic peptide YQPB-2 was prepared according to the method of Example 1: COOH-Thr-Gly-Ser-Gly-Cys-Ala-Asn-Val-NH 2 , mass spectrometry confirmed [MH] -= 708. Typhoid toxin mimetic peptide YQPB-3, the sequence is COOH-Thr-Gly-Ser-Gly-Asn-His-Asn-Val-NH 2 , mass spectrometry confirmed [MH] - = 785. Typhoid toxin mimetic peptide YQPB-4: COOH-Thr-Gly-Set-Gly-Asn-Ala-Asn-Val-NH 2 , mass spectrometry confirmed [MH] - 834. Typhoid toxin mimetic peptide YQPB-5, the sequence is: COOH-Thr-Gly-Ser-Gly-Tyr-Ala-Asn-Val-NH 2 , mass spectrometry confirmed [MH] - = 768. Typhoid toxin mimetic peptide YQPB-6, the sequence is COOH-Thr-Gly-Ser-Gly-Phe-Ala-Ash-Val-NH 2 , mass spectrometry confirmed [MH] - =752.

[0060] Example 3 Preparation of fluorescent targeting compound MPA-YQPB-1

[0061] (1)MPA comes from an invention patent applied for by our research group in the early stage, the authorized patent number is:

[0062] CN101440282

[0063] 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.

[0064] (2) 0.02 mmol of the solid phase synthesized peptide YQPB-1 (X=1-6), 0.1 mmol of triethylamine and 200 μL of ultra-dry DMSO were added to a 5 mL reaction bottle and reacted under nitrogen protection for 10 min; the solution in the above reaction (1) was added to the reaction solution in (2), and the reaction was stirred at room temperature for 12 h.

[0065] (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 InfinityⅡ series HPLC system equipped with Agilent ZORBAX SB-C18 semi-preparative column (9.4×250mm, 5μm) was used, gradient elution was 60 minutes, flow rate was 2mL / 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 to 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; and 50% A and 50% B at 45 minutes. The green product finally obtained was confirmed to be the expected product MPA-YQPB-1 by analytical HPLC and ESI-MS mass spectrometry. In the above preparation process, by replacing the YQPB-1 polypeptide used in the step with the solid-phase synthesized YQPB-X (X=1-6) polypeptide, a variety of other polypeptide compounds MPA-YQPB-1, MPA-YQPB-2, MPA-YQPB-3, MPA-YQPB-4, MPA-YQPB-5, and MPA-YQPB-6 with tumor-targeting optical imaging function can be obtained.

[0066] Example 4 Preparation of radionuclide probes 99m Tc-HYNIC-Aca-YQPB-1 as an example

[0067] 5 mg of the synthesized and purified intermediate (PEG 4 ) 2 E-HYNIC was dissolved in 0.3 mL DMSO, and then 2.1 mg EDCI and 1.25 mg NHS were added. The mixture was reacted at room temperature for 5 hours. The reaction progress was detected by analytical HPLC. After the reaction, 7.8 mg YQPB-1, a peptide analog, was added, and then 5.6 mg DIPEA was added. The mixture was reacted at room temperature for 3 hours. After the reaction, the mixture was separated and purified by preparative liquid chromatography to obtain 6.5 mg of a yellow solid, which was confirmed to be the target product by mass spectrometry.

[0068] Prepare a 100 mg / mL TPPTS (triphenylphosphine tris-sulfonate) solution, a 130.0 mg / mL Tricine (trimethylglycine), and a 102.4 mg / mL succinic acid-sodium succinate buffer solution (including 77.0 mg succinic acid and 25.4 mg sodium succinate), respectively, and take 10.0 μL of TPPTS solution, 10.0 μL of Tricine solution, 10.0 μL of succinic acid-sodium succinate buffer solution and 10.0 μL (1.0 g / mL) of the (YQPB-1) respectively. 2 -(PEG 4 )2 E-HYNIC was mixed in a vial and then 10 mCi Na 99m TcO4 was heated in a 100℃ metal bath for 20 minutes and cooled to room temperature after the reaction was completed to obtain a radionuclide probe (YQPB-1). 2 -(PEG 4 ) 2 E-HYNIC-99mTc, the product was analyzed and identified by Agilent ZORBAX SB-Aq analytical column. The HPLC method used was an Agilent 1220 Infinity II series HPLC system equipped with an online radioactive detector (Flow-RAM) and an Agilent ZORBAX SB-Aq analytical column (4.6×250mm, 5um). The gradient elution was 45 minutes, the flow rate was 1mL / min, and the mobile phase A was ultrapure water (0.01% TFA) and B was acetonitrile (0.01% TFA). The elution gradient was set as follows: 95% A and 5% B at 0-5 minutes; 70% A and 30% B at 15 minutes; 65% A and 35% B at 20 minutes; 45% A and 55% B at 25 minutes; 5% A and 95% B at 45 minutes.

[0069] Affinity of the compound MPA-YQPB-X (X=1-6) prepared in Example 5 for neuroblastoma cells SK-N-SH.

[0070] The cultured human neuroblastoma cells SK-N-SH were washed from the 12-well plate and resuspended in PBS solution, and incubated with MPA-YQPB-X (X=1-6) (10 μmol / L) prepared in the example for 2 hours, and the average fluorescence intensity was detected by flow cytometry. The stronger the fluorescence intensity, the stronger the affinity for the cells. When the probe has a strong affinity with the receptor on the cell, the average fluorescence intensity of the cell detected by the flow cytometer is high, see Figure 1 The results of in vitro affinity experiments showed that after the probes of MPA-YQPB-X (X=1-6) with the same concentration were incubated with neuroblastoma cells SK-N-SH with high expression of gangliosides, the YQPB-1 of the present invention had the strongest affinity with SK-N-SH cells.

[0071] Optical imaging of the compound MPA-YQPB-1 prepared in Example 6 in neuroblastoma SK-N-SH tumor-bearing mice.

[0072] The compound MPA-YQPB-1 prepared in Example 3 was formulated into a physiological saline solution (1 mg / mL), and 15 μL of the drug MPA-YQPB-1 solution was injected into three SK-N-SH nude mice bearing neuroblastoma (weighing about 20 grams) through the tail vein, and optical signal collection was performed 1h, 2h, 4h, 6h, 12h and 24h 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-YQPB-1 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 24h. The imaging results are as follows Figure 2 Among them, the probe is most enriched in the tumor site at 2 hours, while the uptake and clearance in other background organs is faster. From the information of the bladder, it can be inferred that this probe is mainly metabolized by the kidney.

[0073] Optical imaging of the compound MPA-YQPB-2 prepared in Example 7 in mice bearing breast cancer MCF-7 tumor.

[0074] The compound MPA-YQPB-2 prepared in Example 3 was formulated into a physiological saline solution (1 mg / mL), and 15 μL of the drug MPA-YQPB-2 solution was injected into three breast cancer MCF-7 tumor-bearing nude mice (weighing about 20 grams) through the tail vein, and optical signal collection was performed 1h, 2h, 4h, 6h, 12h and 24h 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-YQPB-2 in the three tumor-bearing nude mice were basically consistent. It can be seen from the 1h imaging image 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 24h. The imaging results are as follows Figure 3 Among them, the probe is most enriched in the tumor site at 2 hours, while the uptake and clearance in other background organs is faster. From the information of the bladder, it can be inferred that this probe is mainly metabolized by the kidney.

[0075] Optical imaging of the compound MPA-YQPB-3 prepared in Example 8 in non-small cell lung cancer A549 tumor-bearing mice.

[0076] The compound MPA-YQPB-3 prepared in Example 3 was formulated into a physiological saline solution (1 mg / mL), and 15 μL of the drug MPA-YQPB-3 solution was injected into three non-small cell lung cancer A549 tumor-bearing nude mice (weighing about 20 grams) through the tail vein, and optical signal collection was performed 1h, 2h, 4h, 6h, 12h and 24h 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-YQPB-3 in the three tumor-bearing nude mice were basically consistent. It can be seen from the imaging image at 1h 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 4 Among them, the probe is most enriched in the tumor site at 2 hours, while the uptake and clearance in other background organs is faster. From the information of the bladder, it can be inferred that this probe is mainly metabolized by the kidney.

[0077] Optical imaging of the compound MPA-YQPB-4 prepared in Example 9 in mice bearing HepG2 liver cancer.

[0078] The compound MPA-YQPB-4 prepared in Example 3 was formulated into a physiological saline solution (1 mg / mL), and 15 μL of the drug MPA-YQPB-4 solution was injected into three HepG2 liver cancer tumor-bearing nude mice (weighing about 20 grams) through the tail vein, and optical signal collection was performed 1h, 2h, 4h, 6h, 12h and 24h 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-YQPB-4 in the three tumor-bearing nude mice were basically consistent. From the imaging image of 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 shown in the following figure. Figure 5 Among them, the probe is most enriched in the tumor site at 2 hours, while the uptake and clearance in other background organs is faster. From the information of the bladder, it can be inferred that this probe is mainly metabolized by the kidney.

[0079] Example 10 Radionuclide probe prepared 99m SPECT-CT imaging of Tc-HYNIC-Aca-YQPB-1 in breast cancer 4T1 tumor-bearing mice.

[0080] The prepared in Example 4 99m Tc-HYNIC-Aca-YQPB-1 was prepared into physiological saline solution (1 mg / mL) and injected into three breast cancer 4T1 tumor-bearing nude mice (weighing about 20 g) through the tail vein. 99mTc-HYNIC-Aca-YQPB-1 15μL, and SPECT signal acquisition was performed after administration. The distribution of the probe in the mouse body and its enrichment in the tumor area were observed. The imaging effect is as follows Figure 6 As shown, the radionuclide probe was observed to be distributed in the mouse body and enriched in the tumor area. 99m Tc-HYNIC-Aca-YQPB-1 was significantly taken up in the tumor and was mainly metabolized by the kidney.

Claims

1. A modified tumor-targeting typhoid toxin B subunit mimetic peptide, characterized in that: It has the following general formula: M-YQPB-1, M represents a photolabel, YQPB-1: COOH-Thr-Gly-Ser-Gly-Asn-Ala-Asn-Val-NH2.

2. Use of the modified typhoid toxin B subunit mimetic peptide according to claim 1 in the preparation of a diagnostic reagent targeting neuroblastoma.

3. The use according to claim 2, characterized in that The invention discloses an application of the typhoid toxin B subunit mimetic peptide in the preparation of a neuroblastoma diagnostic imaging agent.

4. The use according to claim 2, characterized in that The typhoid toxin B subunit mimetic peptide is used in the preparation of imaging agents or radionuclide imaging agents for precise positioning of neuroblastoma boundaries or surgical navigation.

5. A radionuclide probe, characterized in that The tumor-targeting typhoid toxin B subunit mimetic peptide YQPB-1 according to claim 1 is labeled with a radionuclide.

6. The radionuclide probe according to claim 5, characterized in that The radionuclide probe is a hydrogen at the adjacent position of the phenolic hydroxyl group of tyrosine in the tumor-targeting typhoid toxin B subunit mimetic peptide YQPB-1 according to claim 1, which is labeled with radioactive iodine or fluorine.

7. The radionuclide probe according to claim 6, characterized in that The radionuclide probe comprises the tumor-targeting typhoid toxin B subunit mimetic peptide YQPB-1 as claimed in claim 1, a linking group, a radionuclide ligand, a bifunctional chelating agent for radionuclide labeling and a radionuclide.

8. The radionuclide probe according to claim 7, characterized in that The bifunctional chelating agent for radionuclide labeling is selected from HYNIC, DOTA, NOTA or DTPA.

9. Use of the radionuclide probe according to any one of claims 5 to 8 in the preparation of an imaging agent for diagnosis of neuroblastoma and intraoperative navigation.

10. The use according to claim 9, characterized in that: Use of the radionuclide probe according to any one of claims 5 to 8 in the preparation of an imaging agent for neuroblastoma diagnosis or intraoperative navigation.

11. The use according to claim 10, characterized in that Use of the radionuclide probe according to any one of claims 5 to 8 in the preparation of imaging agents or radionuclide imaging agents for precise positioning of neuroblastoma boundaries or surgical navigation.

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