Tumor targeting peptides targeting carcinoembryonic antigen-related adhesion molecule CEACAM and their applications

Abstract

The present invention discloses tumor targeting peptides targeting carcinoembryonic antigen-associated adhesion molecules CEACAM and their applications. The present invention provides a class of tumor targeting peptides targeting carcinoembryonic antigen-associated adhesion molecules (CEACAM), which can specifically target tumor CEACAM receptors and can be used for optical imaging after being coupled with fluorescent dyes, so as to accurately locate tumor boundaries for doctors during surgery, guide lesion resection, and help improve the thoroughness of surgery and thus improve prognosis. In addition, this class of targeting peptides can also be coupled with radionuclides for radionuclide imaging to achieve the purpose of early diagnosis and treatment of tumors.

Description

[0001] Description of the case

[0002] This application is a divisional application of the following Chinese invention patent application:

[0003] Parent case application number: 2020105287963;

[0004] Application date: June 11, 2020;

[0005] Invention Name: Tumor targeting peptide targeting carcinoembryonic antigen-related adhesion molecule CEACAM and its application Technical Field

[0006] The invention belongs to the field of bioengineering, and relates to a tumor targeting peptide targeting carcinoembryonic antigen-associated adhesion molecule CEACAM, and a preparation method and application thereof. Background Art

[0007] Malignant tumors are one of the diseases with the highest mortality rate in the world, and the 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 extremely high survival rates. Therefore, early diagnosis and treatment of malignant tumors are crucial. 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.

[0008] Carcinoembryonic antigen-related cell adhesion molecules (CEACAM) are a large family of cell surface adhesion molecules that are involved in many different cell functions, such as proliferation, signal transduction, differentiation, tumor suppression and survival, etc. Therefore, abnormal expression of CEACAM can often be observed in tumor growth and metastasis. With the in-depth study, it was found that carcinoembryonic antigen-related cell adhesion molecules (CEACAM) can be used as an important tumor marker. Its expression in normal human tissues and organs is limited, but its expression level is higher in positive tumors. Therefore, CEACAM receptors can become targets for tumor-specific imaging.

[0009] Peptides that specifically bind to CEACAM receptors can be used as targeting groups for imaging probes. Using small molecule peptides as targeting groups is a common targeting strategy, which has been widely used in the field of tumor targeted therapy, and the research on tumor targeted imaging is also gradually increasing. Compared with monoclonal antibodies, small molecule peptides have the advantages of weak immunogenicity, rapid distribution in the body, strong penetration, and easy synthesis and modification.

[0010] The near-infrared fluorescent dye MPA has the advantages of deeper penetration depth and weaker background tissue autofluorescence, and is more suitable for in vivo imaging. However, MPA cannot specifically bind to tumor cells. The present invention couples a polypeptide that can specifically bind to the CEACAM receptor with the near-infrared fluorescent dye MPA to prepare a near-infrared fluorescent imaging probe targeting the CEACAM receptor. The probe can target and identify tumor cells and tumor lesions that highly express CEACAM receptors in vivo and in vitro, and has good application prospects in fluorescence imaging and fluorescence-guided surgery.

[0011] Single-photon emission tomography / computerized tomography (SPECT / CT) is a new type of nuclear medicine imaging technology developed in the past 20 years. SPECT / CT has been widely used in clinical diagnosis because of its advantages of high sensitivity, high resolution, non-invasiveness, traceable traceability, and good imaging effect. The present invention couples a polypeptide that can specifically bind to the CEACAM receptor with a radionuclide to prepare a radionuclide imaging probe targeting the CEACAM receptor. The probe can target and identify tumor cells and tumor foci that highly express the CEACAM receptor in vivo and in vitro, and has good application prospects in early diagnosis and treatment of tumors.

[0012] Therefore, specific targeting ligands are the key to fluorescence imaging as well as radionuclide imaging. Summary of the invention

[0013] The purpose of the present invention is to provide a tumor targeting peptide targeting carcinoembryonic antigen-associated adhesion molecule CEACAM in view of the above-mentioned deficiencies in the prior art.

[0014] Another object of the present invention is to provide applications of the tumor targeting peptide.

[0015] The purpose of the present invention can be achieved through the following technical solutions:

[0016] The tumor targeting peptide for carcinoembryonic antigen-associated adhesion molecule CEACAM is characterized by being selected from any one of the following polypeptides YQGH-X, where X=1-5:

[0017] YQGH-1, the sequence of which is a polypeptide represented by His-Val-Gly-Leu-Leu-Gln-Ala-Asn-Asn-Ser-NH2;

[0018] YQGH-2, the sequence is a polypeptide represented by Gly-His-Val-Gly-Leu-Leu-Gln-Ala-Gly-Lys-Asn-Asn-Ser-NH2. ;

[0019] YQGH-3, the sequence of which is a polypeptide represented by His-Val-Gly-Leu-Leu-Gln-Ala-Gly-NH2;

[0020] YQGH-4, the sequence is a polypeptide represented by His-Val-Gly-Leu-Gln-NH2;

[0021] YQGH-5, the sequence is obtained by looping the polypeptide represented by His-Val-Gly-Leu-Leu-Gln-Lys from head to tail.

[0022] The tumor targeting peptide of the present invention is used in the preparation of reagents for tumor diagnosis, treatment or tracing; preferably in the preparation of fluorescent imaging or radioactive imaging reagents for tumors.

[0023] The tumor is preferably pancreatic cancer, breast cancer, lung cancer or colorectal cancer.

[0024] The polypeptide compound of the present invention specifically targets carcinoembryonic antigen-associated adhesion molecules (CEACAM) to the tumor site, and has good aggregation and retention at the tumor site, has a high target-to-non-target ratio, is suitable for use as a fluorescent tumor imaging agent and a radionuclide imaging agent and therapeutic agent, and can be used to prepare optical imaging drugs for intraoperative image navigation of tumors and precise positioning of tumor boundaries.

[0025] A modified polypeptide having the following general formula:

[0026] ML-YQGH-X, or M-YQGH-X,

[0027] Wherein, M represents photolabeling or radionuclide labeling;

[0028] L is a linking group;

[0029] YQGH-X is any polypeptide described in the present invention.

[0030] The optical marker is preferably selected from organic chromophores, organic fluorophores, light absorbing compounds, light reflecting compounds, light scattering compounds and bioluminescent molecules; the optical marker is further preferably near-infrared fluorescent dyes MPA, IRDye800, Cy7.5, Cy5.5.

[0031] The radionuclide is preferably 99m Tc, 68 Ga, 64 Cu, 67 Ga, 90 Y, 111 In or 177 Lu, 125 I.

[0032] The L is preferably 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.

[0033] The L is further preferably any one or more of 6-aminocaproic acid, PEG4, PEG6, HYNIC-PEG4 or HYNIC.

[0034] When M represents a light marker, the modified polypeptide is a fluorescent molecular imaging probe used for accurate positioning of tumor boundaries and intraoperative imaging navigation. It is preferably formed by coupling the polypeptide YQGH-X (X=1-5) and the near-infrared fluorescent dye MPA. The preparation method is as follows:

[0035] (1) 0.02 mmol MPA was dissolved in 200 μL ultra-dry DMSO, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide (EDCI / NHS) (molar ratio MPA:EDCI:NHS=1:1.5:1.5) were added, and the mixture was reacted in the dark for 4 h to perform a carboxyl activation reaction.

[0036] (2) 0.02 mmol of the solid phase synthesized peptide YQGH-X (X = 1-5) and 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;

[0037] (3) After the reaction is completed, the reaction solution is concentrated by freeze drying, then diluted with distilled water, loaded onto a C18 preparative column with a chromatographic filler of 10 μm, and gradient eluted with a high performance liquid phase, and the eluted liquid of the target peptide is collected and the purity of the liquid is tested. The eluate is evaporated to remove acetonitrile, and finally freeze-dried with a freeze dryer. The resulting green solid product is the target fluorescent compound, and the mass-to-charge ratio is measured to determine the molecular weight.

[0038] When M represents a radionuclide label, the modified polypeptide is a radionuclide probe.

[0039] In some preferred embodiments of the present invention, the present invention uses radioactive iodine-125 to label the polypeptide YQGH-X (X=1-5), and the labeling method is as follows:

[0040] The iodogen oxidation method can be used to label peptides containing tyrosine, histidine, and tryptophan residues with iodine. Since there are histidine residues in the sequence of the peptide YQGH-X (X=1-5), this method can be used for iodine labeling. First, the iodogen is prepared into a solid phase. Take a 20μL iodogen dichloromethane solution, blow it dry with nitrogen under slight heating, so that a uniform iodogen film is formed on the EP tube. When labeling, add phosphate buffer (PH=7.4) containing 10μg of YQGH-X (X=1-5) peptide to the iodogen EP tube, and then add 500μCi of Na 125 I. After shaking and reacting at room temperature for 2 minutes, remove the reaction solution in the tube and add 50 μL of phosphate buffer (PH=7.4) to dilute it. The radioactive mixture can be purified by C18 column to obtain the radioactive product 125 I-YQGH-X (X=1-5) The radiolabeled product was confirmed by high performance liquid chromatography (HPLC) equipped with a radioactivity detector.

[0041] In other preferred embodiments of the present invention, the present invention utilizes radionuclides 99m Tc is used to label the peptide YQGH-X (X=1-5) to obtain radioactive nuclides 99m The preparation method of the Tc-labeled probe comprises the following steps:

[0042] (1) Synthesis of bifunctional chelating agent HYNIC-NHS

[0043] 6-Chloronicotinic acid and 80% hydrazine hydrate are added to a 500mL eggplant-shaped bottle, heated under reflux for 6h, cooled to room temperature after the reaction is completed, added with distilled water for dilution, then adjusted to pH=5.3, solid is precipitated, filtered and dried to obtain a light yellow solid, the product is confirmed to be 6-hydrazinicotinic acid by ESI-MS mass spectrum and nuclear magnetic hydrogen spectrum. The obtained 6-hydrazinicotinic acid and p-aminobenzaldehyde are added to dimethylformamide (DMF), heated for 2h, after the reaction is completed, distilled water is added to precipitate solid, filtered and dried, solid is added to DMF together with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) and N-hydroxysuccinimide (NHS) to react at room temperature, after the reaction is completed, most of the solvent is evaporated, solid is precipitated after adding water, the crude product is purified by silica gel column and confirmed to be the target product by ESI-MS mass spectrum and nuclear magnetic hydrogen spectrum.

[0044] (2) Synthesis of HYNIC-YQGH-X (X = 1-5)

[0045] 2 moles of purified HYNIC-NHS and 1 mole of polypeptide YQGH-X (X=1-5) were dissolved in DMSO, and then 3 moles of triethylamine were added. The reaction was allowed to react at room temperature for 6 hours. The reaction progress was monitored by analytical high performance liquid chromatography. After the reaction was completed, separation and purification were performed by preparative liquid chromatography, and finally confirmed by mass spectrometry.

[0046] (3) Radioactive probes 99m Synthesis of Tc-HYNIC-YQGH-X (X = 1-5)

[0047] Prepare 5 mL of a mixture containing 5.0 mg of TPPTS (triphenylphosphine trisulfonate), 6.5 mg of Tricine (trimethylglycine), 38.5 mg of disodium succinate hexahydrate, 12.7 mg of succinic acid and 20 μg of HYNIC-YQGH-X (X=1-8) in a 10 mL vial, then add 10-50 mCi of Na 99m The TcO4 solution was heated in a water bath at 100°C for 15 minutes and cooled to room temperature after the reaction was completed to prepare a peptide radiopharmaceutical. The product was analyzed and identified using an Agilent ZORBAX SB-Aq analytical column.

[0048] The modified polypeptide of the present invention is used in the preparation of reagents for tumor diagnosis, treatment or tracing; preferably in the preparation of fluorescent imaging or radioactive imaging reagents for tumors.

[0049] The tumor is preferably pancreatic cancer, breast cancer, lung cancer or colorectal cancer.

[0050] Beneficial effects:

[0051] 1. The present invention provides a type of tumor targeting peptides targeting carcinoembryonic antigen-related adhesion molecules (CEACAM). Such peptides can specifically target tumor CEACAM receptors and can be used for optical imaging after being coupled with fluorescent dyes. During surgery, doctors can accurately locate tumor boundaries and guide lesion resection, which helps to improve the thoroughness of surgery and thus improve prognosis. In addition, such targeted peptides can also be coupled with radionuclides for radionuclide imaging to achieve the purpose of early diagnosis and treatment of tumors.

[0052] 2. These peptides are all low molecular weight peptides with low synthesis cost, and the natural amino acids in this series of short peptides are replaced by non-natural amino acids, which will improve the stability of the peptides in vivo.

[0053] 3. The peptides of the present invention are reported for the first time and are easily available.

[0054] 4. YQGH-X (X=1-5) series peptides can specifically bind to tumor cells. In vivo optical imaging and radionuclide imaging results have shown that they have excellent imaging effects on a variety of tumors, including pancreatic cancer, breast cancer, lung cancer and colorectal cancer.

[0055] 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.

[0056] 6. YQGH-X (X=1-5) 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

[0057] Figure 1 The structure (A) and MS (B) of the fluorescent targeting compound MPA-YQGH-5.

[0058] Figure 2 This is the optical imaging of the compound MPA-YQGH-5 in pancreatic cancer CFPAC-1 tumor-bearing mice.

[0059] Figure 3 This is the optical imaging of MPA-YQGH-5 in pancreatic cancer CFPAC-1 tumor-bearing mice after being blocked by YQGH-5.

[0060] Figure 4 This is the optical imaging of the compound MPA-YQGH-1 in breast cancer MCF-7 tumor-bearing mice.

[0061] Figure 5 Optical imaging of compound MPA-YQGH-2 in A549 lung cancer tumor-bearing mice

[0062] Figure 6 Optical imaging of compound MPA-YQGH-3 in colorectal cancer HT-29 tumor-bearing mice

[0063] Figure 7 Targeted radiopharmaceuticals 125 I - Structural diagram of YQGH-3.

[0064] Figure 8 For radiopharmaceuticals 125 SPECT-CT imaging of I-YQGH-3 in A549 lung cancer tumor-bearing mice.

[0065] Fig. 9 For radiopharmaceuticals 125 SPECT-CT imaging of I-YQGH-4 peptide in pancreatic cancer BxPC-3 tumor-bearing mice.

[0066] Fig.10 For radiopharmaceuticals 125 SPECT-CT imaging of I-YQGH-5 peptide in pancreatic cancer SW1990 tumor-bearing mice.

[0067] Fig.11 The structure (A) and MS (B) of compound HYNIC-PEG4-YQGH-1.

[0068] Fig.12 Targeted radiopharmaceuticals 99m Structural diagram of Tc-HYNIC-PEG4-YQGH-1.

[0069] Fig.13 For radiopharmaceuticals 99m SPECT-CT imaging of Tc-HYNIC-PEG4-YQGH-1 in pancreatic cancer CFPAC-1 tumor-bearing mice.

[0070] Fig.14 For radiopharmaceuticals 99m SPECT-CT imaging of Tc-HYNIC-YQGH-3 in colorectal cancer SW480 tumor-bearing mice.

[0071] Fig.15 For radiopharmaceuticals 99m SPECT-CT imaging of Tc-HYNIC-YQGH-5 in mice bearing MCF-7 breast cancer. DETAILED DESCRIPTION

[0072] The present invention is further illustrated below by means of specific embodiments and application examples: the chemical substances used in the synthesis steps are all existing substances or commercially available products.

[0073] Example 1 Preparation of YQGH-1

[0074] (1) Resin swelling

[0075] 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.

[0076] (2) Removal of Fmoc

[0077] Add 20% hexahydropyridine in DMF solution to the reaction column and perform deprotection once every 5 minutes and once every 8 minutes. After the reaction is completed, wash the resin three times with DMF, DCM, and DMF, respectively.

[0078] (3) Coupling

[0079] Accurately weigh 3 times the molar number of the feed resin Fmoc-Ser-OH and O-benzotriazole-tetramethyluronium hexafluorophosphate (HBTU), completely dissolve in DMF, add N, N-diisopropylethylamine (DIPEA) to activate the carboxyl group, add the solution to the reaction column for reaction, react for 30 minutes, wash with DMF, DCM, and DMF three times respectively, 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 DMF, DCM, and DMF three times respectively. Repeat the above operation, and couple other amino acids in turn until the last amino acid Fmoc-His(trt)-OH is coupled, wash the obtained peptidyl resin with methanol, and dry it in a vacuum drying oven.

[0080] (4) Cracking

[0081] Take 120mL 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, naturally settle for 30min. Then centrifuge to obtain solid, wash solid three times with ether, after gained precipitation is dried, obtain dry powder crude product.

[0082] (5) Purification

[0083] 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 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 lyophilized to obtain the target polypeptide, and finally the mass-to-charge ratio was measured to determine the molecular weight to be 1051.17.

[0084] Example 2 Preparation of cyclic polypeptide YQGH-5

[0085] (1) Resin swelling

[0086] 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.

[0087] (2) Removal of Fmoc

[0088] Add 20% hexahydropyridine DMF solution to the reaction column and perform deprotection once every 5 minutes and once every 8 minutes. After the reaction is completed, wash the resin 3 times with DMF, DCM, and DMF, respectively.

[0089] (3) Coupling

[0090] Accurately weigh 3 times the molar number of the feed resin Fmoc-Lys(trt)-OH and O-benzotriazole-tetramethyluronium hexafluorophosphate (HBTU), completely dissolve in DMF, add N, N-diisopropylethylamine (DIPEA) to activate the carboxyl group, add the solution to the reaction column for reaction, react for 30 minutes, wash with DMF, DCM, and DMF three times respectively, 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 DMF, DCM, and DMF three times respectively. Repeat the above operation, and couple other amino acids in turn until the last amino acid Fmoc-His(trt)-OH is coupled, wash the obtained peptidylresin with methanol, and dry it in a vacuum drying oven.

[0091] (4) Cracking

[0092] Take 120mL 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, naturally settle for 30min. Then centrifuge to obtain solid, wash solid three times with ether, after gained precipitation is dried, obtain dry powder crude product.

[0093] (5) End-to-end loop

[0094] In a 1L eggplant-shaped bottle, add HOBT 135.1mg (1mmol) and PyBOP 520.4mg (1mmol) respectively, and dissolve in 1mL of DMF, then add redistilled DCM 150mL and DIPEA 1.74mL (10mmol). Take 0.20mmol of the crude product in the above step (4) and dissolve it in 200mL of redistilled DCM, and add it to the constant pressure dropping funnel. Then evacuate the above device, fill it with nitrogen for protection, place the eggplant-shaped bottle in ice water at 0℃, and slowly add the solution in the constant pressure dropping funnel. After 4h of dropping, react at room temperature overnight.

[0095] (6) Purification

[0096] After the reaction, the DCM in the reaction solution was drained by rotary evaporator. Methanol was used as buffer and loaded onto a C18 preparative column with a chromatographic filler of 10 μm. The eluted liquid of the target peptide was collected and the purity of the liquid was tested. The qualified samples were mixed and then rotary evaporated to remove acetonitrile. Finally, the samples were freeze-dried by freeze dryer. The obtained white powder was the target peptide. The mass-to-charge ratio was measured and the molecular weight was determined to be 775.95.

[0097] Example 3 Preparation of fluorescent targeting compound MPA-YQGH-5

[0098] MPA comes from an invention patent applied for by our research group in the early stage, and the authorized patent number is: CN101440282.

[0099] (1) 12 mg of MPA was dissolved in 200 μL of ultra-dry DMSO, and 3.7 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 2.2 mg of 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 a carboxyl activation reaction.

[0100] (2) Weigh 10 mg of the peptide YQGH-5 synthesized by the solid phase carrier, 6.5 mg of triethylamine and 200 μL of ultra-dry DMSO into 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;

[0101] (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 MPA-YQGH-5 by analytical HPLC and ESI-MS mass spectrometry, see Figure 1In the above preparation process, the YQGH-X (X=1-5) polypeptide synthesized in solid phase is used to replace the YQGH-5 polypeptide used in the previous step, thereby obtaining various other polypeptide compounds having tumor targeting optical imaging function of the present invention.

[0102] Optical imaging of the prepared compound MPA-YQGH-2 in lung cancer A549 tumor-bearing mice

[0103] The compound MPA-YQGH-2 prepared in the same manner as in Example 3 was formulated into a physiological saline solution (600 μg / mL), and 100 μL of the drug MPA-YQGH-2 solution was injected into three nude mice bearing lung cancer A549 (weighing about 22 grams) through the tail vein. Optical signal acquisition was performed 1h, 2h, 4h, 8h, 12h and 24h after administration. The distribution of the probe in the mouse body and its enrichment in the tumor area were observed. The 2h imaging results are shown in Figure 2. Figure 5 As shown, the probe MPA-YQGH-2 was significantly taken up in the tumor site, indicating that this probe could target lung cancer A549 tumor cells, and the metabolites were mainly excreted through the kidney-bladder.

[0104] The present invention is based on the principle of specific binding of YQGH-X (X=1-5) polypeptides to CEACAM receptors, and utilizes the advantages of high expression of CEACAM receptors in malignant tumors such as pancreatic cancer, breast cancer, lung cancer, and colorectal cancer, as well as the advantages of deeper penetration depth of near-infrared fluorescent dye MPA and weaker background tissue autofluorescence, so as to be able to target and identify tumor cells and tumor foci that highly express CEACAM receptors, and has good application prospects in fluorescence imaging and fluorescence-guided surgery. At the same time, this series of polypeptides can also be coupled with radionuclides, and the drugs labeled with nuclei in vivo are concentrated to the tumor site through the targeting effect of YQGH-X (X=1-5) polypeptides, and the single-photon tomography technology of nuclear medicine is used to perform imaging diagnosis on a variety of tumors. The present invention relates to the field of drugs related to tumor diagnosis, and specifically to multiple polypeptides, and pharmaceutical compositions with these polypeptides as active ingredients, and their use in the preparation of diagnostic drugs.

Claims

1. YQGH-2, a tumor targeting peptide targeting carcinoembryonic antigen-associated adhesion molecule CEACAM, is characterized by The amino acid sequence is shown as Gly-His-Val-Gly-Leu-Leu-Gln-Ala-Gly-Lys-Asn-Asn-Ser-NH2.

2. Use of the tumor targeting peptide YQGH-2 according to claim 1 in the preparation of reagents for lung cancer diagnosis or tracing.

3. The use according to claim 2, characterized in that Use of the tumor targeting peptide YQGH-2 according to claim 1 in the preparation of fluorescent imaging or radioactive imaging agents for lung cancer.

4. A modified polypeptide, characterized in that With the following general formula: ML-YQGH-2, or M-YQGH-2, Wherein, M represents photolabeling or radionuclide labeling; L is a linking group; YQGH-2 is the tumor targeting peptide according to claim 1.

5. The modified polypeptide according to claim 4, characterized in that The optical marker is selected from the group consisting of organic chromophores, organic fluorophores, light absorbing compounds, light reflecting compounds, light scattering compounds and bioluminescent molecules.

6. 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.

7. 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.

8. 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, N3S type ligand, N2S2 type ligand, diethyltriamine pentaacetic acid, 1,4-succinic acid, 5-aminovaleric acid, polyethyleneimine, 6-hydrazinopyridine-3-carboxylic acid, benzyl bromoformate, N-(2-aminoacetic acid)maleimide or a combination thereof.

9. The modified polypeptide according to claim 8, characterized in that The L is selected from any one or more of 6-aminocaproic acid, PEG4, PEG6, HYNIC-PEG4 or HYNIC.

10. Use of the modified polypeptide according to any one of claims 4 to 9 in the preparation of a reagent for diagnosis, treatment or tracing of lung cancer.

11. The use according to claim 10, characterized in that Use of the modified polypeptide according to any one of claims 4 to 9 in the preparation of a fluorescent imaging or radioactive imaging agent for lung cancer.

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