Cyclic peptide compound, pharmaceutical composition and application

Abstract

The invention relates to the technical field of medicines, and provides a cyclic peptide compound, a pharmaceutical composition and application. The cyclopeptide compound provided by the invention has a structure as shown in a formula I. The cyclopeptide compound has remarkable EphA2 targeting affinity, has remarkable drug development potential on an EphA2 target spot, and has a wide application prospect in diagnosis, prevention and treatment of related diseases with high expression of EphA2. The result of the embodiment shows that the affinity constant KD of the cyclopeptide compound provided by the invention and an EphA2 target is between 1 * 10 <-9 > M and 1 * 10 <-7 > M, the cyclopeptide compound is difficult to dissociate after being combined with the target, and meanwhile, the cyclopeptide compound has very strong competitive capacity for a ligand Ephrin-A1 of the EphA2 target. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the field of pharmaceutical technology, and in particular to a cyclic peptide compound, a pharmaceutical composition and an application thereof. Background Art

[0002] Targeted drugs developed based on differential gene expression between tumors and normal tissues have achieved great success in the clinic. Eph receptor tyrosine kinase A2 (EphA2) is highly expressed in a variety of human tumors, and plays an oncogene function that drives tumor proliferation, migration and invasion, and has the potential to be a target for tumor therapy. Targeting EphA2 can effectively inhibit tumor growth and restore the sensitivity of drug-resistant tumor cells to drugs.

[0003] Although EphA2 was initially studied in the context of neuronal migration during embryogenesis, it has been shown to regulate tumor cell growth, migration, invasion, and angiogenesis. As an oncogenic target, EphA2 is highly expressed in a variety of tumor types, such as the cervix, ovary, breast, lung, prostate, colon, and esophagus, relative to normal tissues, especially in more aggressive cancer phenotypes, and is significantly negatively correlated with patients' overall survival and recurrence-free survival. Therefore, overexpression of EphA2 has been considered an important marker for tumor occurrence, development, and drug resistance, and may serve as a new target for anti-tumor therapy. It is particularly important to explore the molecular mechanism by which the EphA2 oncogene drives the tumor development process, which has gradually become a hot topic in tumor treatment research.

[0004] EphA2 targeted therapy research has appeared in clinical trials of various types and stages of malignant tumors. In clinical studies, the oncogenic function of EphA2 is inhibited according to the different mechanisms of EphA2 in the signaling pathway to achieve the purpose of treatment. At present, the main research directions are as follows:

[0005] 1) Reduce the expression of EphA2: Inhibit the carcinogenic function of EphA2 by reducing its expression. The drugs used include EphA2 targeted drugs and small molecule inhibitors. EphA2 expression can also be reduced by RNA interference technology (RNAi). 2) Promote the degradation of EphA2: Artificial ligands or antibodies that interact with EphA2 can inhibit signals by promoting internalization and degradation. 3) EphA2-based combination therapy: By combining different treatment methods, targeting the EphA2 target to achieve better therapeutic effects. For example, the combination of the new EphA2-targeted liposome (EphA2-ILs-DTXp) and anti-PD-1 can significantly increase the infiltration of CD8+T cells in tumor tissues, synergistically improving the infiltration and killing ability of immune cells against tumors.

[0006] Although a large number of preclinical studies have been conducted on EphA2-based targeted therapy, unfortunately, there are not many successful clinical results of EphA2-targeted therapy. Therefore, based on the important role of EphA2 in tumor development and the current limitations of clinical development of this target, it is of great clinical significance and social value to find a ligand that highly specifically targets EphA2 and then use it for the diagnosis and treatment of patients with tumors that overexpress EphA2. Summary of the invention

[0007] In view of this, the present invention provides a cyclic peptide compound and a pharmaceutical composition and application. The cyclic peptide compound provided by the present invention has significant EphA2 targeting affinity and has significant drug development potential on the EphA2 target.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] A cyclic peptide compound and a pharmaceutically acceptable salt and stereoisomer thereof, wherein the cyclic peptide compound has a structure shown in Formula I:

[0010]

[0011] In formula I: X1 and X2 independently represent a peptide sequence consisting of 5 to 7 amino acids, the nitrogen end of the peptide sequence is connected to the carbon end of the main chain, and the carbon end of the peptide sequence is connected to the nitrogen end of the main chain;

[0012] R1, R2, R3, R4, R5 and R6 are independently H or an alkyl group having 1 to 5 carbon atoms; m1, m2, m3 are 1 or 2; n1 is 1 or 2.

[0013] Preferably, the peptide sequence represented by X1 is any one of the following sequences:

[0014]

[0015]

[0016] Preferably, the peptide sequence represented by X2 is any one of the following sequences:

[0017]

[0018] Preferably, R1 and R2 are methyl, m1, m2, m3 are 1, R3, R4, R5, R6 are H, and n1 is 1 or 2.

[0019] Preferably, R1 and R2 are H, m1, m2, m3 are 1, R3 and R4 are H or methyl, R5 and R6 are H, and n1 is 1 or 2.

[0020] Preferably, R1, R2, R3, R4, R5 and R6 are H, m1, m2, m3 are 1, and n1 is 1 or 2.

[0021] Preferably, the cyclic peptide compound is one or more of the structures shown in Table 1:

[0022] Table 1 Structure of cyclic peptide compounds

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030] The present invention also provides a pharmaceutical composition comprising an active ingredient and a pharmaceutically acceptable excipient, wherein the active ingredient comprises the cyclic peptide compound described in the above scheme and a pharmaceutically acceptable salt and stereoisomer thereof.

[0031] The present invention also provides the use of the cyclic peptide compound described in the above scheme and its pharmaceutically acceptable salt, stereoisomer or the pharmaceutical composition described in the above scheme in the preparation of drugs for diagnosing, preventing or treating diseases overexpressing EphA2.

[0032] Preferably, the disease overexpressing EphA2 includes one or more of prostate cancer, lung cancer, breast cancer, gastric cancer, ovarian cancer, esophageal cancer, multiple myeloma and fibrosarcoma.

[0033] The present invention provides a cyclic peptide compound and a pharmaceutically acceptable salt and stereoisomer thereof, wherein the cyclic peptide compound has a structure shown in Formula I. The cyclic peptide compound and a pharmaceutically acceptable salt and stereoisomer thereof provided by the present invention have significant EphA2 targeting affinity, and have broad application prospects in the diagnosis, prevention and treatment of diseases related to high expression of EphA2, which is conducive to improving the deficiencies of existing EphA2 targeted drugs, meeting clinical needs, and promoting the progress of personalized tumor medicine. The results of the examples show that the affinity constant KD of the cyclic peptide compound provided by the present invention and the EphA2 target is between 1×10 -9 M to 1×10 -7 M, and some compounds are difficult to dissociate after binding to the target (dissociation rate constant Kdis<1×10 -2M). At the same time, the cyclic peptide compound provided by the present invention has a strong competitive ability (IC 50 <0.1 μM); the above results show that the cyclic peptide compound of the present invention has significant drug development potential on the EphA2 target. DETAILED DESCRIPTION

[0034] The present invention provides a cyclic peptide compound and a pharmaceutically acceptable salt and stereoisomer thereof. The cyclic peptide compound has a structure shown in Formula I:

[0035]

[0036] In formula I: X1 and X2 independently represent a peptide sequence consisting of 5 to 7 amino acids, the nitrogen end of the peptide sequence is connected to the carbon end of the main chain, and the carbon end of the peptide sequence is connected to the nitrogen end of the main chain;

[0037] R1, R2, R3, R4, R5 and R6 are independently H or an alkyl group having 1 to 5 carbon atoms; m1, m2, m3 are 1 or 2; n1 is 1 or 2.

[0038] In the present invention, R1, R2, R3, R4, R5 and R6 are preferably independently H or an alkyl group having 1 to 3 carbon atoms, and more preferably independently H or a methyl group.

[0039] In the present invention, X1 and X2 independently contain 5, 6 or 7 amino acids.

[0040] In the present invention, the peptide sequence represented by X1 is preferably any one of the following sequences:

[0041]

[0042]

[0043] In the present invention, the peptide sequence represented by X2 is any one of the following sequences:

[0044]

[0045] In the present invention, when R1 and R2 are methyl groups, m1, m2, and m3 are preferably 1, R3, R4, R5, and R6 are preferably H, and n1 is preferably 1 or 2.

[0046] In the present invention, when R1 and R2 are H, m1, m2, and m3 are preferably 1, R3 and R4 are preferably H or methyl, R5 and R6 are preferably H, and n1 is preferably 1 or 2.

[0047] In the present invention, when R1, R2, R3, R4, R5 and R6 are H, m1, m2 and m3 are preferably 1, and n1 is preferably 1 or 2.

[0048] In the present invention, the cyclic peptide compound is one or more of the structures described in Table 1 (see above).

[0049] In the present invention, the preparation method of the cyclic peptide compound adopts the standard Fmoc chemical method.

[0050] In a specific embodiment of the present invention, the method for preparing the cyclic peptide compound preferably comprises the following steps:

[0051] According to the amino acid sequence of the crude peptide intermediate shown in formula II, a peptide sequence is prepared on a resin to obtain a peptide resin;

[0052] The peptide resin is cleaved by a cleavage solution to obtain a crude peptide intermediate, the structural formula of which is shown in Formula II;

[0053] Carrying out a cyclization reaction between the crude peptide intermediate and the compound of the structure represented by formula III to obtain the cyclic peptide compound;

[0054]

[0055] According to the amino acid sequence of the cyclic peptide compound described in the above technical scheme, the present invention prepares a peptide sequence on a resin to obtain a peptide resin. In the present invention, the resin may be MBHAResin, and the MBHAResin is sequentially swollen and Fmoc protecting group removed before use. In an embodiment of the present invention, the reagent used for the swelling is dichloromethane; after the swelling, the solvent is preferably drained and washed with N,N-dimethylformamide. In a specific embodiment of the present invention, the reagent used for removing the Fmoc protecting group is a N,N-dimethylformamide solution of piperidine, wherein the volume ratio of piperidine to N,N-dimethylformamide is 1:4; specifically, the removal of the Fmoc protecting group includes sequentially carrying out a first stage reaction and a second stage reaction; the temperature of the first stage reaction is room temperature and the time is 5 minutes; the temperature of the second stage reaction is room temperature and the time is 10 minutes.

[0056] The present invention does not specifically limit the specific method for preparing the peptide sequence on the resin, and a method well known to those skilled in the art can be used. In the embodiment of the present invention, specifically according to the amino acid sequence of the intermediate shown in Formula II, the Fmoc-protected amino acids are sequentially coupled to the resin, and then the Fmoc protecting group is removed to obtain the peptide resin.

[0057] In one embodiment of the present invention, specifically, Fmoc-protected amino acids, 2-(1H-benzotriazolyl L-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate, N,N-diisopropylethylamine and N,N-dimethylformamide are mixed for activation; then the obtained activation solution is mixed with the resin from which the Fmoc protecting group is removed for coupling reaction, and then the above operation is repeated to sequentially couple other Fmoc-protected amino acids. In a specific embodiment of the present invention, the activation is carried out under ice bath conditions, and the activation time is 10 minutes; the coupling reaction is carried out under room temperature conditions, and the coupling reaction time is 1 hour.

[0058] In the embodiment of the present invention, the operation of removing the Fmoc protecting group after coupling the Fmoc-protected amino acid can be performed by referring to the scheme of removing the Fmoc protecting group from the resin in the above scheme, which will not be repeated here.

[0059] After the coupling is completed, the present invention preferably washes the obtained peptide resin and then dries it to obtain the peptide resin; in the present invention, the peptide chain in the peptide resin is a peptide chain with a side chain protecting group (denoted as intermediate 1), and the side chain protecting group is removed in the subsequent cleavage process.

[0060] After obtaining the peptide resin, the present invention uses a cleavage solution to cleave the peptide resin to obtain a crude peptide intermediate. In a specific embodiment of the present invention, the cleavage solution includes trifluoroacetic acid (TFA), triisopropylsilane (TIS), water and 1,8-octanedithiol (EDT), and the volume ratio of TFA, TIS, H2O and EDT is 92.5:2.5:2.5:2.5; the cleavage is preferably carried out at room temperature, and the cleavage time is preferably 2h. After the cleavage, the present invention preferably filters the obtained cleavage liquid, collects the filter cake and washes it with the cleavage solution, adds methyl tert-butyl ether dropwise to the combined filtrate, centrifuges after sedimentation under ice bath conditions, collects the solid, washes it with methyl tert-butyl ether and dries it to obtain the crude peptide intermediate (referred to as intermediate 2).

[0061] After obtaining the crude peptide intermediate, the present invention performs a cyclization reaction on the crude peptide intermediate and the compound of the structure shown in formula III to obtain the cyclic peptide compound. In the present invention, when the value of n1 in formula III is 1, the compound of the structure shown in formula III is TATA, and the structural formula of TATA is as follows.

[0062]

[0063] In a specific embodiment of the present invention, the cyclization reaction is preferably carried out in the presence of acetonitrile and a buffer solution; the preparation method of the buffer solution is preferably: sodium bicarbonate and EDTA are added to water, the concentration of sodium bicarbonate is controlled to be 20mM, the concentration of EDTA is controlled to be 5mM, and then TEA is added to adjust the pH value of the solution to 8. The temperature of the cyclization reaction is preferably room temperature, and the reaction time is preferably 2h; specifically, the crude peptide intermediate can be first dissolved in acetonitrile, and then the pH value of the solution is adjusted to 8 using a buffer solution, and then the compound of the structure shown in formula III is added to react. After the cyclization reaction, the obtained product system is purified by Pre-HPLC to obtain a purified solution, which is concentrated and freeze-dried to obtain the cyclic peptide compound.

[0064] The present invention also provides a pharmaceutical composition, comprising an active ingredient and a pharmaceutically acceptable excipient, wherein the active ingredient comprises the cyclic peptide compound and a pharmaceutically acceptable salt and stereoisomer thereof as described in the above scheme. In the present invention, the pharmaceutically acceptable excipient may be a carrier and / or an excipient; the present invention has no special requirements for the specific types of the carrier and / or excipient, and those familiar to those skilled in the art may be used.

[0065] The present invention also provides the use of the cyclic peptide compound described in the above scheme and its pharmaceutically acceptable salt, stereoisomer or the pharmaceutical composition described in the above scheme in the preparation of a drug for diagnosing, preventing or treating a disease overexpressing EphA2; the disease overexpressing EphA2 includes one or more of prostate cancer, lung cancer, breast cancer, gastric cancer, ovarian cancer, esophageal cancer, multiple myeloma and fibrosarcoma.

[0066] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] Example 1 Synthesis of Compound HTPM7019-053

[0068]

[0069] The peptides were synthesized using standard Fmoc chemistry, with the following specific steps:

[0070] (1) Swelling: MBHAResin (0.35 g, 0.2 mmol) was placed in a peptide synthesis tube and swollen with dichloromethane (DCM) (15 mL) for 15 min at room temperature, and the solvent was drained. The tube was dried, washed with DMF (15 mL) for 3 times, and the solvent was drained.

[0071] (2) Removal of Fmoc protecting group: Add piperidine DMF solution (10 mL, Vpiperidine: VDMF = 1:4) to the Fmoc peptide resin obtained above, react at room temperature for 5 min, drain, add piperidine DMF solution (10 mL, Vpiperidine: VDMF = 1:4) again and react at room temperature for 10 min. After the reaction is completed, drain the reaction solution, wash it with DMF (10 mL) 6 times, and drain the solvent. Take a small amount of resin and heat it with 5% ninhydrin ethanol solution at 110°C for 3 min. The resin turns dark blue, indicating that Fmoc has been removed, and is directly used for the next reaction.

[0072] (3) Coupling: Fmoc-Cys(Trt)-OH (320 mg, 0.6 mmol, 3 eq) and 2-(1H-benzotriazol L-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU) (193 mg, 0.6 mmol, 3 eq) were dissolved in DMF (20 mL). DIEA (0.208 mL, 1.2 mmol, 6 eq) was added to the reaction solution and stirred for activation for 10 min under an ice bath. The activated solution was added to the resin from which the Fmoc protecting group was removed and reacted at room temperature for 1 h. A small amount of the resin was added to a 5% ninhydrin ethanol solution and heated at 110°C for 3 min. The resin turned colorless. The reaction solution was drained and washed with DMF (10 mL) 3 times. The obtained resin was directly used for the next reaction.

[0073] (4) Coupling cycle, repeat the above steps to couple the following amino acids one by one:

[0074] Fmoc-Arg(Pbf)-OH(3.0eq.0.39g);

[0075] Fmoc-Trp(Boc)-OH(3.0eq.0.32g);

[0076] Fmoc-D-Asp(OtBu)-OH(3.0eg.0.25g);

[0077] Fmoc-Pro-OH (3.0eg. 0.20g);

[0078] Fmoc-His(Trt)-OH(3.0eg.0.37g);

[0079] Fmoc-Leu-OH (3.0eg. 0.21g);

[0080] Fmoc-Cys(Trt)-OH(3.0eg.0.35g);

[0081] Fmoc-Leu-OH (3.0eg. 0.21g);

[0082] Fmoc-Pro-OH (3.0eg. 0.20g);

[0083] Fmoc-Asn(Trt)-OH(3.0eg.0.36g);

[0084] Fmoc-Aib-OH (3.0eg. 0.20g);

[0085] Fmoc-Leu-OH (3.0eg. 0.21g);

[0086] Fmoc-Hyp(tBu)-OH(3.0eg.0.25g);

[0087] Fmoc-Cys(Trt)-OH (3.0eg.0.35g).

[0088] After all amino acid couplings were completed, the Fmoc protection was removed by the operation in step (2). Then, the mixture was washed alternately with 10 mL of DCM and EtOH for 3 times, dried, transferred to a vacuum oven, and dried under vacuum at 35° C. for 2 h to obtain H-Cys(T rt)-Hyp(tBu)-Leu-Aib-Asn(Trt)-Pro-Leu-Cys(Trt)s-Leu-His(Trt)-Pro-D-Asp(OtBu)-Trp(Boc)-Arg(Pbf)-Cys(Trt)-MBHA resin intermediate 1 (0.98 g), which was directly used in the next reaction.

[0089] (5) Cleavage: Add cleavage solution (10 mL, 10 mL / g resin, TFA:TIS:H2O:EDT volume ratio of 92.5:2.5:2.5:2.5) to 0.98 g resin, react for 2 h, filter, and wash the resin with cleavage solution (1 mL). Add methyl tert-butyl ether (MTBE) (50 mL) dropwise to the combined filtrate, let settle in an ice bath for 1 h, and centrifuge. Wash with methyl tert-butyl ether (40 mL) three times to obtain a white solid. Transfer the solid to a vacuum drying oven and vacuum dry at 35°C for 2 h to obtain crude peptide intermediate 2 (160 mg).

[0090] (6) Cyclization: The crude peptide intermediate 2 was dissolved in MeCN (20 mL), and then a buffer solution (20 mL, aqueous buffer solution: 20 mM NH4HCO3, 5 mM EDTA, TEA adjusted to pH = 8) was added, and TATA (22.1 mg 1.1 eq) was slowly added under stirring at room temperature, and the reaction solution was stirred at room temperature for 2 h. LC-MS showed that the reaction was complete, and the purified solution was purified by Pre-HPLC (mobile phase A: 20 mmol ammonium acetate aqueous solution, mobile phase B: acetonitrile), concentrated and lyophilized to obtain a white solid HTPM7019-053 (26.1 mg, purity 93.7%, yield 14%), LCMS (ESI) m / z = (M+2H + ) / 2=1009.2,(M+3H + ) / 3=672.7.

[0091] According to the similar operation method described in Example 1, by replacing different amino acids, the compounds in Table 2 were synthesized:

[0092] Table 2 Structure and characterization data of cyclic peptide compounds

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100] Example 2 Affinity test of compounds for EphA2 target

[0101] The affinity of the compound in Example 1 to the target protein EphA2 was tested using the Bio-Layer Interferometry (BLI) technique. The specific steps are as follows:

[0102] The Octet device was used for the experiment, and the biotinylated recombinant human EphA2 protein (Acro Biosystems Inc. Catalog No. EP2-H82E4, concentration of 30 μg / mL, prepared with PBST) was fixed to the SA sensor, and the protein immobilization value was >4nm. The immobilized sensor was subjected to a binding reaction with the compound. The compound was prepared into a 10mM master solution using DMSO. According to the affinity level of the compound, the highest test concentration was set, and PBST was used to dilute the gradient to 5 concentrations by 2 times. The final DMSO concentration was controlled within 1% to ensure that the amount of DMSO used did not affect the activity of the protein. Different concentrations of compounds and PBST were added to a 96-well plate, and the program was set: Baseline (PBST buffer containing DMSO, 60s), Association (containing compound solution, 90s), Dissociation (PBST buffer containing DMSO, 120s), and each sample well was required to perform an equilibrium binding and dissociation step. At the same time, the above operation was performed on the sensor without immobilized protein as a reference.

[0103] After the experiment, the Octet high-throughput analysis software Octet Analysis Studio (version 12.2.2.26) was used for analysis. The data processing followed the double subtraction principle, that is, the first step was to subtract the non-specific binding signal between the sensor and the compound, and the second step was to subtract the non-specific binding signal between the protein and the PBST buffer containing DMSO. Then, the 1:1 model was selected in the Binding Model for kinetic fitting to obtain the affinity constant KD between the compound and the target protein. The test results are shown in Table 3.

[0104] Example 3 Competitive inhibition ELISA test of compounds on EphA2 target

[0105] The competitive ELISA technique was used to test the competitive effect of the example compound with the ligand Ephrin-A1 of the target protein EphA2. The specific steps are as follows:

[0106] Ephrin-A1 was diluted to 2 μg / mL with 1x coating solution, and 50 μL was added to a 384-well ELISA plate and placed at 4°C overnight. The next day, the plate was dried and washed 3 times with 1×PBST. 100 μL of PBST solution containing 2% BSA was added to each well and allowed to stand at room temperature for 90 min. The plate was dried and washed 3 times with 1×PBST.

[0107] The compound was diluted with PBST solution containing 0.5% BSA to 8 concentrations of 20000nM (2×), 6666.6nM (2×), 2222.2nM (2×), 740.7nM (2×), 246.9nM (2×), 82.3nM (2×), 27.4nM (2×), and 9.1nM (2×). 30μL of compound solution was aspirated and added to a new PCR plate for use. The recombinant humanBio-EphA2 protein was diluted with PBST solution containing 0.5% BSA to 0.6μg / mL (2×), and 30μL of protein solution (2x) was aspirated and added to the PCR plate to mix with the compound and incubated at room temperature for 40min. Then 50μL of the mixed solution was aspirated into a 384 plate and incubated at room temperature for 60min. Each well was washed 3 times with 100μL 1×PBST. HRP-labeled streptavidin was diluted with 0.5% BSA in PBST solution at a ratio of 1:5000, and 50 μL of HRP solution was added to each well and allowed to stand for 30 min.

[0108] Under light-proof conditions, add 50 μL TMB to each well, and after 20 to 30 minutes, place it in a microplate reader to read (read OD650, when the "0 point" OD650 reading reaches between 0.85 and 1.0, add stop solution). Prepare stop solution by diluting 18M H2SO4 to 1M with ultrapure water, add 25 μL stop solution to each well, and then place it in a microplate reader to read OD450. The BLI and ELISA data of the tested cyclic peptide compounds are summarized in Table 3:

[0109] Table 3 Summary of BLI and ELISA data of cyclic peptide compounds

[0110]

[0111]

[0112] Note: “ / ” means not tested.

[0113] The experimental results in Table 3 show that the cyclic peptide compound of the present invention has significant targeting affinity for the EphA2 target, and the affinity constant KD of the cyclic peptide compound and the EphA2 target is between 1×10 -9 M to 1×10 -7 M, and some compounds are difficult to dissociate after binding to the target (dissociation rate constant Kdis<1×10 -2 M). At the same time, most compounds have strong competitive ability against Ephrin-A1, the ligand of EphA2 target (IC 50<0.1 μM). Compared with BT5528, some cyclic peptide compounds have better affinity to the EphA2 target than BT5528. The above results show that the cyclic peptide compounds of the present invention have significant drug development potential on the EphA2 target.

[0114] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A cyclic peptide compound and its pharmaceutically acceptable salts and stereoisomers, characterized in that: The cyclic peptide compound has a structure shown in Formula I: In formula I: X1 and X2 independently represent a peptide sequence consisting of 5 to 7 amino acids, the nitrogen end of the peptide sequence is connected to the carbon end of the main chain, and the carbon end of the peptide sequence is connected to the nitrogen end of the main chain; R1, R2, R3, R4, R5 and R6 are independently H or an alkyl group having 1 to 5 carbon atoms; m1, m2, m3 are 1 or 2; n1 is 1 or 2.

2. The cyclic peptide compound and its pharmaceutically acceptable salt and stereoisomer according to claim 1, characterized in that: The peptide sequence represented by X1 is any one of the following sequences:

3. The cyclic peptide and pharmaceutically acceptable salts and stereoisomers thereof according to claim 1, characterized in that: The peptide sequence represented by X2 is any one of the following sequences:

4. The cyclic peptide compound and its pharmaceutically acceptable salt and stereoisomer according to claim 1, characterized in that: R1 and R2 are methyl groups, m1, m2, m3 are 1, R3, R4, R5, R6 are H, and n1 is 1 or 2.

5. The cyclic peptide compound and its pharmaceutically acceptable salt and stereoisomer according to claim 1, characterized in that: R1 and R2 are H, m1, m2, m3 are 1, R3 and R4 are H or methyl, R5 and R6 are H, and n1 is 1 or 2.

6. The cyclic peptide compound and its pharmaceutically acceptable salt and stereoisomer according to claim 1, characterized in that: R1, R2, R3, R4, R5 and R6 are H, m1, m2, m3 are 1, and n1 is 1 or 2.

7. The cyclic peptide compound and pharmaceutically acceptable salt and stereoisomer thereof according to any one of claims 1 to 6, characterized in that: The cyclic peptide compound is one or more of the following structures:

8. A pharmaceutical composition, characterized in that The invention comprises active ingredients and pharmaceutically acceptable excipients, wherein the active ingredients comprise the cyclic peptide compound according to any one of claims 1 to 7 and pharmaceutically acceptable salts and stereoisomers thereof.

9. Use of the cyclic peptide compound according to any one of claims 1 to 7 and its pharmaceutically acceptable salt, stereoisomer or the pharmaceutical composition according to claim 8 in the preparation of a drug for diagnosing, preventing or treating a disease overexpressing EphA2.

10. The use according to claim 9, characterized in that: The diseases overexpressing EphA2 include one or more of prostate cancer, lung cancer, breast cancer, gastric cancer, ovarian cancer, esophageal cancer, multiple myeloma and fibrosarcoma.

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