UPAR targeting polypeptide, novel targeting polypeptide probe and preparation method and application thereof

Abstract

The invention belongs to the technical field of radiopharmaceuticals, and particularly relates to a uPAR targeting polypeptide, a targeting polypeptide probe and a preparation method and application of the uPAR targeting polypeptide probe. The invention provides a polypeptide probe targeting uPAR, and the polypeptide probe is used for PET molecular imaging diagnosis through radiolabeling. The targeting polypeptide probe shows good tumor targeting in an animal body, the uptake of a tumor tissue is remarkably different from that of a normal tissue, the background of the normal tissue is clear, and the targeting polypeptide probe can be used for preparing a tumor imaging agent or preparing a tumor peptide targeting radionuclide treatment probe, and can be used for preparing a tumor imaging agent or a tumor peptide targeting radionuclide treatment probe. The targeted polypeptide probe provides a powerful tool and a theoretical basis for noninvasive precise diagnosis of uPAR positive cancers.

Description

Technical Field

[0001] This invention belongs to the field of radiopharmaceutical technology, specifically relating to a uPAR-targeting polypeptide, a novel targeting polypeptide probe, its preparation method, and its application. Background Technology

[0002] Cancer is one of the world's most significant health challenges, causing nearly 10 million deaths annually according to the World Health Organization, making it the second leading cause of death globally. The complexity of cancer stems from its high heterogeneity between and within tumor types, its ability to evade immune detection, and its tendency to develop resistance to treatment over time. Furthermore, cancer patients have poor prognoses, and cancer-related deaths are projected to rise significantly over the next decade. The lack of obvious symptoms in the early stages of the disease, coupled with delayed diagnosis, remains a major challenge in clinical practice. In addition, the lack of specific and reliable biomarkers is a primary reason hindering early cancer diagnosis.

[0003] Urokinase-type plasminogen activator receptor (uPAR) is a highly glycosylated membrane protein anchored to the cell membrane surface via C-terminal glycosylated phosphatidylinositol (GPI). uPAR mediates various cell surface biological activities, including plasminogen activation, extracellular matrix (ECM) remodeling, cell adhesion and migration, and intracellular signaling. Under normal physiological conditions, uPAR is typically expressed at low levels, but transiently increases in expression during tissue remodeling, wound healing, inflammation, and embryogenesis. Numerous studies have shown that uPAR is highly expressed in various types of human cancers and is closely associated with the invasion and metastasis of malignant tumors. uPAR plays an important role in ECM degradation, tumor angiogenesis, cell proliferation, and apoptosis, and is associated with multidrug resistance (MDR) in tumor cells, providing important guidance for the assessment and prognosis of malignant tumors.

[0004] uPAR, a promising diagnostic biomarker, has its high-affinity targeting peptide AE105 currently undergoing clinical trials, with the potential application in the diagnosis and treatment of uPAR-overexpressing cancers. Compared to other strategies targeting uPAR, such as monoclonal antibodies, antibody-drug conjugates (ADCs), and chimeric antigen receptor T cells (CAR-T), peptide-based probes offer several unique advantages. Due to their smaller molecular weight, peptides can penetrate tumor tissue more efficiently, achieving rapid and uniform distribution in solid tumors. Their rapid clearance in vivo significantly reduces background signal, making them particularly suitable for molecular imaging applications such as positron emission tomography (PET). Furthermore, peptides exhibit lower immunogenicity, are convenient and inexpensive to synthesize, and their structure can be easily optimized through cyclization or the introduction of non-natural amino acids, thereby enhancing their stability and uPAR binding capacity.

[0005] In summary, the aforementioned superior properties make peptides a promising diagnostic and therapeutic platform for uPAR-positive cancers. Summary of the Invention

[0006] Based on the aforementioned technical background, the main objective of this invention is to provide a uPAR-targeting peptide, a targeting probe, its preparation method, and its applications. This invention detects the tumor-specific binding ability of the uPAR-targeting peptide PDT02 at the protein level, in vitro cell level, and animal level. This uPAR-targeting peptide PDT02 can specifically bind to uPAR. A radionuclide probe is formed using the peptide labeled with a radionuclide. This probe can efficiently target uPAR-positive MKN45 tumor cells in in vitro and in vivo experiments, and clearly visualize tumor lesions in in vivo animal imaging. The targeting probe demonstrates good tumor targeting and promising diagnostic and therapeutic applications. This invention provides a new approach for preparing uPAR-related diagnostic reagents and tumor-targeted therapeutic drugs.

[0007] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: The first aspect of this invention is to provide a uPAR-targeting polypeptide, the chemical structure of which is shown in formula (1): Equation (1).

[0008] In formula (1), X is a chelating group selected from DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), 1,4,7,10-tetraazacyclododecane, 1-(glutaric acid)-4,7,10-triacetic acid, 1,4,7-triazacyclononyl-N',N”-diacetic acid-N-acetyl, 2S-(4-isothiocyanobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid, 1,4,7-triazacyclononane-N-glutaric acid-N',N”-diacetic acid, or 1,4,7-triazacyclononane-1,4-diacetic acid-methylphenylacetic acid.

[0009] Preferably, the chelating group is a group formed from DOTA.

[0010] The uPAR-targeting peptide is obtained by conjugation of a peptide and a chelate.

[0011] The amino acid sequence of the uPAR-targeting polypeptide precursor is CRWDLSC, as shown in SEQ ID NO.1. This targeting polypeptide can specifically bind to the tumor molecular marker uPAR.

[0012] The derivatives of the uPAR-targeting peptide PDT02 include radionuclide complex conjugates.

[0013] A second aspect of the present invention is to provide an application of the uPAR-targeting peptide PDT02 in the preparation of tumor-targeted therapeutic drug formulations, the application including applications such as targeting peptide conjugation with anti-tumor molecules and tumor-targeted nanocarrier systems.

[0014] The applications of the uPAR-targeting peptide PDT02 also include its use in the diagnosis of tumors with peptide preparations, especially as a tumor pathology diagnostic probe and a tumor-targeting molecular imaging probe.

[0015] A third aspect of the present invention is to provide a targeting peptide probe, wherein the targeting peptide probe is obtained by complexing the targeting peptide described in the first aspect of the present invention with a radioactive ion.

[0016] The radioactive ions are selected from 18 F, 51 Cr 67 Ga、 68 Ga、 111 In、 99 mTc, 186 Re、 188 Re、 139 La、 140 La、 175 Yb、 153 Sm、 166 Ho、 88 Y、 90 Y、 149 Pm, 165 Dy、 169 Er、 177 Lu、 47 Sc、 142 Pr, 159 Gd, 212 Bi、 213 Bi、 72 As、 72 Se、 97 Ru、 109 Pd, 105 Rh、 101 ᵐRh、 119 Sb、 128 Ba、 123 I, 124 I, 131 I, 197 Hg, 211 At、 151 Eu、 153 Eu、 169 Eu、 201 Tl、 203 Pb, 212 Pb, 64 Cu、67 Cu、 188 Re、 186 Re、 198 Au、 225 Ac、 227 Th、 199 One of the ions that forms in Ag is the geoid.

[0017] Preferably, the radioactive ion is 68 Ga ions are formed.

[0018] PDT02 targets peptides and forms complexes with radionuclides. 68 Ga radionuclide targeting peptide probes were intravenously injected into tumor-bearing mice. PET / CT showed that the probes had good targeting and aggregation on uPAR-positive subcutaneous gastric cancer xenografts.

[0019] This invention also protects the use of the uPAR-targeting peptide PDT02 in the preparation of uPAR-positive tumor-targeting drugs.

[0020] This invention also protects the use of derivatives of the uPAR-targeting peptide PDT02 for the preparation of uPAR-positive tumor-targeting drugs.

[0021] This invention also protects the use of targeted peptide probes in uPAR-positive tumor diagnostic or therapeutic drugs.

[0022] A fourth aspect of the present invention is to provide a method for preparing the uPAR-targeting polypeptide probe described in the third aspect of the present invention, the method comprising the following steps: Step 1: Synthesize peptides using a solid-phase peptide synthesis method; Step 2: After removing the last cysteine ​​protecting group of the peptide obtained in Step 1, a chelating group is added, and after purification, the uPAR-targeting peptide is obtained. Step 3: The uPAR-targeting peptide solution is heated and reacted with a radioactive metal ion solution. After extraction, the targeting peptide probe is obtained.

[0023] The fifth aspect of this invention is to provide the application of the targeted polypeptide probe described in the third aspect of this invention in the preparation of tumor imaging agents or in the preparation of tumor peptide-targeted radionuclide therapeutic probes.

[0024] The tumors include those that express uPAR positively, such as gastric cancer.

[0025] A sixth aspect of the present invention is to provide a kit comprising the targeting peptide probe described in the third aspect of the present invention.

[0026] The kit can be directly applied to preclinical or clinical diagnostic scenarios, simplifying the usage process and improving testing efficiency.

[0027] The beneficial effects of this invention are as follows: (1) The uPAR-targeting polypeptide PDT02 described in this invention can specifically bind to the tumor molecular marker uPAR. Biolayer interferometry (BLI) verification showed that its dissociation constant Kd with uPAR protein reached 531.3 nM, indicating that the targeting polypeptide and the tumor molecular marker have good affinity. This targeting polypeptide can accurately identify uPAR-positive tumor cells and efficiently target MKN45 tumor cells in in vitro and in vivo experiments, effectively distinguishing tumor tissue from normal tissue.

[0028] (2) The targeted polypeptide probe of the present invention has a small molecular weight and has better tumor tissue penetration compared with monoclonal antibodies, ADC drugs and CAR-T strategies. It can be rapidly and uniformly distributed in solid tumors and has a fast in vivo circulation clearance speed, which can reduce background signal interference. It is especially suitable for molecular imaging diagnostic needs such as PET.

[0029] The targeted peptide probe has low immunogenicity, good biocompatibility, and higher safety when used in vivo. It also has lower synthesis cost and simpler preparation process, making it more likely to be mass-produced and clinically applied than antibody drugs, and can effectively reduce medical costs.

[0030] In PET / CT imaging of tumor-bearing mice, the targeted peptide probe can be specifically taken up by the tumor site, while other organs only show a small amount of distribution in metabolic organs such as the kidneys and bladder, with a clear background of normal tissue. This significantly improves the clarity and accuracy of tumor lesion detection. The targeted peptide probe provides a reliable tool for the non-invasive and precise diagnosis of uPAR-positive cancers.

[0031] (3) The targeted polypeptide probe described in this invention can be used as a tumor pathological diagnostic detection probe and a targeted molecular imaging probe. It is not only applicable to the verified uPAR-positive tumor types such as gastric cancer, but can also be extended to other cancer types with high uPAR expression. It solves the problem of lack of specific biomarkers in the existing early diagnosis of cancer and provides a new approach for early disease screening and disease assessment.

[0032] The targeted peptides can be used to develop tumor-targeted therapeutic drug formulations by conjugating anti-tumor molecules and constructing tumor-targeted nanocarrier systems. At the same time, combined with radionuclide labeling technology, tumor peptide-targeted radionuclide therapeutic probes can be prepared to achieve integrated diagnosis and treatment, providing a new strategy for precision cancer treatment. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 The HPLC chromatogram of the PDT02 precursor compound (peptide compound) is shown. Figure 2 The HR-MS analysis spectrum of the PDT02 precursor compound is shown. Figure 3 The results of the biolayer interference (BLI) assay for the targeted peptide PDT02 are shown. Figure 4 PDT02 labeled radionuclides are shown 68 Ga ( 68 A schematic diagram of the structure of Ga-PDT02; Figure 5 The radiometric HPLC chromatogram of the PDT02 radionuclide-coupled probe (i.e., the targeted peptide probe) is shown. Figure 6 The results of PET / CT imaging of small animals with PDT02 radionuclide-coupled probes in the control group are shown. Figure 7 The statistical results of PET / CT imaging of small animals in the experimental group using PDT02 radionuclide-coupled probes (i.e., targeted peptide probes) are shown. Figure 8 The following are the statistical results of the signal-to-noise ratio in small animal PET / CT imaging of PDT02 radionuclide-coupled probes in the control group; Figure 9 The statistical results of signal-to-noise ratio in small animal PET / CT imaging of PDT02 radionuclide-coupled probes in the experimental group are shown. Detailed Implementation

[0035] The present invention will now be described in detail, and its features and advantages will become clearer and more apparent from these descriptions.

[0036] The polypeptides provided by this invention can be produced using methods known in the art. They can be produced using cellular methods and cell-free in vitro transcription / translation methods, or synthesized using techniques known in the art, such as liquid-phase methods, solid-phase methods, etc., for chemical synthesis.

[0037] The uPAR-targeting peptide provided by this invention was obtained through phage display library screening and identification. After tumor targeting verification, it has good targeting ability against tumors that express uPAR positive. It can be linked or used in combination with existing anti-tumor drugs, drug delivery systems and molecular imaging agents to realize a new method for tumor diagnosis and treatment.

[0038] Example The present invention is further illustrated below with specific examples. These embodiments are merely illustrative and not intended to limit the scope of the invention. All reagents used in this invention are commercially available or can be prepared using the methods described herein. Cell lines used in this invention are commercially available, such as those from the Cell Bank of the Chinese Academy of Sciences.

[0039] Example 1 Phage display of random peptide library for bio-particle screening of uPAR-specific binding peptides.

[0040] 1. Coating target protein: Add 50 μL of sterile streptavidin magnetic beads to a 1.5 mL centrifuge tube, wash twice with PBS, add 10 μg of biotinylated target protein, bind at 37℃ for 1 h, discard the biotinylated target protein after 1 h, add 0.1% BSA blocking solution, and bind at 37℃ for 1 h.

[0041] 2. Phage Display Random Peptide Library Biopanning: Remove BSA (bovine serum albumin) blocking solution and wash five times with PBS-T (phosphate buffer containing 0.1% Tween-20). Take 10 μL of the original phage display random peptide library (original library titer 2 × 10⁻⁶). 12 The solution (pfu / mL) was diluted with 1 mL of 0.1% PBS-T, mixed well, and added to a centrifuge tube containing streptavidin magnetic beads. The mixture was then incubated at room temperature for 1 h.

[0042] 3. Remove unbound phage display peptides: Wash 10 times with 0.1% PBS-T, and rinse away any residual liquid after each wash.

[0043] 4. Elution of bound phage display peptides: Add 1 mL of acidic elution buffer (0.2 M Glycine-HCl, pH=2.2), elute for 30 min at room temperature, then add 200 μL of alkaline neutralization buffer (1 M Tris-HCl, pH=9.1) to neutralize, collect the total liquid to obtain phages that can bind to the target protein, and take 10 μL for titer measurement or storage.

[0044] 5. Amplification and Preparation of the Next Round of Phage: Add the acid-base neutralized and eluted phage to 30 mL of XL1-Blue host bacteria in logarithmic growth phase and incubate at 37 °C with shaking for 4.5 h. Transfer the bacterial culture to a centrifuge tube and centrifuge at 12000 rpm for 10 min at 4 °C. Transfer the supernatant to a new centrifuge tube and centrifuge again at the same parameters for 10 min. Collect approximately 80% of the supernatant and transfer it to a new centrifuge tube. Add 1 / 6 volume of PEG / NaCl (20% (w / v) PEG-8000, 2.5 M NaCl, PEG polyethylene glycol) and incubate overnight at 4 °C. After overnight incubation, centrifuge at the same parameters for 10 min, discard the supernatant, centrifuge again for 10 min to remove the supernatant, collect the precipitate, resuspend in 2 mL of PBS, centrifuge for 5 min, and transfer the supernatant to a new centrifuge tube to obtain the amplified phage. Take 10 μL for titer measurement, and use the remaining phage for the next round of biopanning or preservation.

[0045] 6. Phage Display Peptide Sequence Acquisition: The bound phages eluted by acid and alkali in the third round of screening were used to infect the host bacterium XL1-Blue and then plated on Amp agarose plates for amplification. After overnight incubation, the plaques represent the phage-infected host bacteria. All plaques were scraped off, centrifuged, and the E. coli precipitate was used for plasmid extraction. The extracted plasmid was sequenced using the -pComb-PCR-11 primer (5'-TCGTCGGCAGCGTCAGATGTGTATAAGAGACAGGGAGGAATTTAAAATGAAAAAGACAGCTATCG-3'), as shown in SEQ ID NO.2. The sequence was transcribed and translated into an amino acid sequence according to the triplet codons. The sequence with the highest repetition was used to obtain the uPAR-specific binding polypeptide (abbreviated as polypeptide) described in this invention by deletion / replacement of amino acids. Its amino acid sequence is CRWDLSC.

[0046] Example 2 Chemical synthesis of uPAR-targeting peptide PDT02: The uPAR-targeting peptide PDT02 was constructed on MBHA resin (polystyrene resin) using the standard Fmoc solid-phase synthesis method.

[0047] MBHA resin was washed with DMF (dimethylformamide) (10 mL × 3 times, 2 min each time); Fmoc (amino protectant) deprotection was performed using 3% piperidine + 3% DBU + 94% DMF (3 times × 10 mL × 5 min each time). Amino acid incorporation was performed using 3 equivalents of amino acids + 3 equivalents of HBTU (O-benzotriazole-tetramethylurea hexafluorophosphate) + 4 equivalents of HOBT (1-hydroxybenzotriazole) + 6 equivalents of DIEA (N,N-diisopropylethylamine) + 10 mL of DMF, reacted at room temperature for 1 h, yielding a uPAR-specific binding peptide, abbreviated as peptide, with the amino acid sequence: CRWDLSC.

[0048] After attaching all amino acids sequentially from the carboxyl terminus to the amino terminus, remove the last cysteine ​​Fmoc protecting group and then attach DOTA.

[0049] After DOTA incorporation, the MBHA resin was washed three times each with DMF, DCM (dichloromethane), and MeOH (methanol). After drying, 10 mL of peptide cleavage solution (95% TFA, 2% H2O, 2% TIPS (sodium tris(1-methylethyl)naphthalenesulfonate), 1% 2-mercaptoethanol) was added, and the mixture was reacted at room temperature for 3 h. The reaction solution was concentrated by rotary evaporation, and then extracted with ice-cold ether (10 mL) and water (2 × 10 mL). The aqueous phase was collected and lyophilized to obtain the peptide precursor, which was purified by preparative HPLC (high performance liquid chromatography) to obtain the uPAR-targeting peptide PDT02.

[0050] The HPLC purification method was as follows: the mobile phase consisted of acetonitrile containing 0.1% trifluoroacetic acid (TFA) and water containing 0.1% TFA, and the flow rate of the mobile phase was set to 6 mL / min. The gradient elution program was as follows: initially, the phase was 90% aqueous, and then gradually transitioned to 100% acetonitrile by min 90.

[0051] HPLC analysis showed that the chemical purity was greater than 98%. Figure 1 As shown.

[0052] HRMS analysis confirmed that the structure of the chemically synthesized uPAR-targeting peptide PDT02 of this invention is correct. Figure 2 As shown: PDT02: Calculated: 1267.4430, Found: 1267.4437. Example 3: Affinity Verification Using Biolayer Interference (BLI) The affinity of the uPAR-targeting peptide PDT02 prepared in Example 2 to uPAR was detected using a Sartorius BLI assay kit. The specific test method is as follows: the receptor uPAR protein concentration was set to 200 nM, the initial uPAR-targeting peptide concentration was set to 50 μg / mL, and the uPAR-targeting peptide was serially diluted five times in a 2-fold gradient, with the lowest concentration of the uPAR-targeting peptide being 6.25 nM. The affinity test results are shown below. Figure 3 As shown.

[0053] Figure 3 In the study, BLI analysis showed that the dissociation constants Kd of the targeting peptide PDT02 and uPAR protein were 531.3 nM, respectively, indicating that the peptides obtained by phage panning have good affinity for uPAR protein.

[0054] Example 4 Utilizing 68 Ga-DOTA-PDT02 probe for tumor-bearing mouse PET / CT 1. Based on the uPAR-specific binding peptide obtained in Example 1, a uPAR-targeting peptide PDT02 modified with the chelate DOTA was chemically synthesized.

[0055] 2. Establishment of tumor-bearing mice: Female nude mice aged 4-6 weeks were selected, and MKN45-huPAR cells were subcutaneously injected into the axilla of the right forelimb of each mouse. The injection volume was 1×10⁻⁶ cells per mouse. 7 The tumor volume is calculated based on the formula v=a*b (individual cells). 2 / 2 (a is the long diameter of the tumor, b is the short diameter of the tumor). When the tumor volume reaches 400-600 mm... 3 Then proceed to the next step.

[0056] 3. Preparation of radionuclide-labeled probes (i.e., targeted peptide probes): Prepare a 1 mg / mL PDT02 peptide solution (i.e., uPAR targeted peptide solution) using DMSO (dimethyl sulfoxide). Place 20 μL of the PDT02 peptide solution into a clean 5 mL centrifuge tube. Inject 3 mL of 0.1 M HCl into the germanium-gallium generator to obtain 3 mL of radioactive... 68 Ga metal ion solution was added to 345 μL of 1M NaAc solution to adjust the pH to 4.1, and then immediately added to a centrifuge tube containing PDT02 peptide solution. The reaction was heated at 105°C for 15 min. The reaction product was purified by C18 extraction column (Waters (USA) Co., Ltd., WAT023051) to obtain the desired product. 68 Ga-PDT02 radionuclide-labeled probes (i.e., targeted peptide probes) can be used as diagnostic drugs, and their structure is as follows: Figure 4 As shown.

[0057] Example 5 Tumor-bearing mice were injected with targeted peptide probes: Tumor-bearing mice were divided into two groups of four mice each. The groups included: (1) Control group (control group), where each nude mouse was directly injected with 200 μL of the probe via the tail vein. 68 Ga-PDT02 targeting peptide probe, radiochemical purity greater than 90% at 200 μCi (e.g.) Figure 5 )of 68 Ga-PDT02; (2) Block group (experimental group): Each nude mouse was pre-injected via tail vein with 100 μL of 2.5 mg / mL non-radioactively labeled PDT02-targeting peptide, followed by a tail vein injection of 200 μL of 200 μCi radiochemically pure peptide with a purity greater than 90% 15 min later. 68 Ga-PDT02.

[0058] Tumor-bearing mouse PET / CT: All groups of mice were injected with... 68 Timing was started after Ga-PDT02 was applied, and the circulation time was recorded. Images were acquired using a MadicLab small animal PET / CT scanner 30 and 60 minutes after in vivo metabolism. The imaging results are as follows: Figure 6 As shown, tumor sites can specifically take up 68 Ga-PDT02 (see Figure 6 The area indicated by the white circle in the middle is mainly distributed in metabolic organs such as the kidneys and bladder in other organs. Pre-injection of PDT02 in the Block group significantly reduced the tumor's impact on... 68 The uptake of Ga-PDT02 and the imaging results are as follows: Figure 7 As shown above, the results indicate that the targeted peptide probe has good specificity.

[0059] Example 6 Image Analysis After acquiring PET / CT images in Example 5, radionuclide uptake values ​​of the tumor and various organs were analyzed using a three-dimensional volume model. The statistical results are as follows: Figure 8 , Figure 9 As shown.

[0060] from Figure 8 and Figure 9 As can be seen from the data, the uptake values ​​of radionuclides in various organs after 60 minutes show that the tumor site has specific uptake. The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A uPAR-targeting polypeptide PDT02, characterized in that, The chemical structure of the uPAR-targeting peptide PDT02 is shown in formula (1): Equation (1); In formula (1), X is a chelating group.

2. The uPAR-targeting polypeptide PDT02 according to claim 1, characterized in that, The chelating group is selected from one of the following groups: DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), 1,4,7,10-tetraazacyclododecane, 1-(glutaric acid)-4,7,10-triacetic acid, 1,4,7-triazacyclononyl-N',N”-diacetic acid-N-acetyl, 2S-(4-isothiocyanobenzyl)-1,4,7-triazacyclononane-1,4,7-triacetic acid, 1,4,7-triazacyclononane-N-glutaric acid-N',N”-diacetic acid, or 1,4,7-triazacyclononane-1,4-diacetic acid-methylphenylacetic acid.

3. The application of a uPAR-targeting polypeptide PDT02 in the preparation of tumor-targeted therapeutic drug formulations, characterized in that, The applications include targeted peptide-coupled anti-tumor molecules and tumor-targeted nanocarrier systems.

4. The application according to claim 3, characterized in that, The application of the uPAR-targeting peptide PDT02 also includes its application in the diagnosis of tumors using peptide preparations.

5. A targeting peptide probe, characterized in that, The targeting peptide probe is obtained by complexing the targeting peptide PDT02 as described in claim 1 or 2 with radioactive ions.

6. The targeting peptide probe according to claim 5, characterized in that, The radioactive ions are selected from 18 F, 51 Cr 67 Ga、 68 Ga、 111 In、 99 mTc, 186 Re、 188 Re、 139 La、 140 La、 175 Yb、 153 Sm、 166 Ho、 88 Y、 90 Y、 149 Pm, 165 Dy、 169 Er、 177 Lu、 47 Sc、 142 Pr, 159 Gd, 212 Bi、 213 Bi、 72 As、 72 Se、 97 Ru、 109 Pd, 105 Rh、 101 ᵐRh、 119 Sb、 128 Ba、 123 I, 124 I, 131 I, 197 Hg, 211 At、 151 Eu、 153 Eu、 169 Eu、 201 Tl、 203 Pb, 212 Pb, 64 Cu、 67 Cu、 188 Re、 186 Re、 198 Au、 225 Ac、 227 Th、 199 One of the ions that forms in Ag is the geoid.

7. A method for preparing the targeting peptide probe according to claim 5 or 6, the method comprising the following steps: Step 1: Synthesize peptides using a solid-phase peptide synthesis method; Step 2: After removing the last cysteine ​​protecting group of the peptide obtained in Step 1, a chelating group is added, and after purification, the uPAR-targeting peptide is obtained. Step 3: The uPAR-targeting peptide solution is heated and reacted with a radioactive metal ion solution. After extraction, the targeting peptide probe is obtained.

8. The use of the targeting peptide probe of claim 5 or 6 in the preparation of tumor imaging agents or in the preparation of tumor peptide-targeting radionuclide therapeutic probes.

9. The application according to claim 8, characterized in that, The tumors include those that express uPAR positively.

10. A reagent kit, characterized in that, The kit includes the targeting peptide probe as described in claim 5 or 6.

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