A camptothecin polypeptide anti-tumor drug conjugate, its preparation method and application

Abstract

The present invention discloses a camptothecin polypeptide anti-tumor drug conjugate, its preparation method and application, belonging to the field of drug conjugate synthesis. Using cysteine as an intermediate linker, cysteine is grafted onto 9-aminocamptothecin and a targeted anti-tumor polypeptide by amidation reaction, and then oxidized to form a disulfide bond to couple 9-aminocamptothecin and the targeted anti-tumor polypeptide. The camptothecin polypeptide anti-tumor drug conjugate of the present invention can specifically target and act on tumor sites and tumor cells, enabling drug molecules to highly accumulate at the tumor site, having high tumor targeting and retention, achieving targeted precision chemotherapy, reducing the toxic and side effects on the body. At the same time, the conjugate form effectively improves the stability of 9-aminocamptothecin, prolongs the blood circulation half-life of the drug, and continuously exerts anti-tumor efficacy.

Description

Technical Field

[0001] The present invention belongs to the field of synthesis of drug conjugates, and particularly relates to a camptothecin polypeptide anti-tumor drug conjugate, a preparation method thereof, and an application thereof. Background Art

[0002] Camptothecin is a plant anti-cancer drug with the chemical formula C 20 H 16 N 2 O 4 , which is a cytotoxic quinoline alkaloid that can inhibit DNA topoisomerase (TOPO I). By binding to the complex formed by TopoⅠ-DNA, the broken DNA strands cannot be reconnected, preventing DNA replication and RNA synthesis. It is a cell cycle S-phase specific drug, has no effect on G0-phase cells, and has a slight killing effect on G1, G2, and M-phase cells. However, camptothecin and its derivatives do not have targeting properties, and are non-specifically distributed in the body after administration. After long-term administration, serious toxic and side effects will occur. In addition, as a small molecule drug, camptothecin is easily decomposed during blood circulation after administration, cannot be effectively accumulated in tumor cells, has a short half-life, and poor stability. Its active lactone ring is easily converted into an inactive carboxylate structure, thereby losing its anti-cancer efficacy.

[0003] Based on the above, for the first time in the present invention, cysteine is used as an intermediate linker, cysteine is grafted onto 9-aminocamptothecin and polypeptide HYD-PEP06 by amidation reaction, and then oxidized to form a disulfide bond to couple 9-aminocamptothecin and polypeptide HYD-PEP06. The synthesized anti-tumor drug conjugate can specifically target and act on tumor sites and tumor cells, enabling drug molecules to highly accumulate at the tumor site, achieving targeted precision chemotherapy, reducing the toxic and side effects on the body. At the same time, the conjugate form effectively improves the stability of 9-aminocamptothecin, extends the blood circulation half-life of the drug, and continuously exerts anti-tumor efficacy. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a camptothecin polypeptide anti-tumor drug conjugate, a preparation method thereof, and an application thereof.

[0005] The technical solution of the present invention is outlined as follows:

[0006] A camptothecin polypeptide anti-tumor drug conjugate: using cysteine as an intermediate linker, cysteine is grafted onto 9-aminocamptothecin and a targeting anti-tumor polypeptide by amidation reaction, and then oxidized to form a disulfide bond to couple 9-aminocamptothecin and the targeting anti-tumor polypeptide.

[0007] Further, the targeted anti-tumor polypeptide is polypeptide HYD-PEP06, and its amino acid sequence is Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met.

[0008] Further, the structural formula of the anti-tumor drug conjugate is shown in Formula I:

[0009]

[0010] Among them, R is Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met.

[0011] A preparation method of a camptothecin polypeptide anti-tumor drug conjugate includes the following steps:

[0012] S1: Add 9-aminocamptothecin into 1,4-dioxane solvent, stir to dissolve it, then add cysteine and condensing agent EDC / HOBt, and carry out magnetic stirring reaction at 20 - 30 °C for 3 - 5 h to obtain the first reaction solution of Cys-9-aminocamptothecin;

[0013] S2: Add the targeted anti-tumor polypeptide into tetrahydrofuran solvent, stir to dissolve it, then add cysteine and condensing agent EDC / HOBt, and carry out magnetic stirring reaction at 20 - 30 °C for 3 - 5 h to obtain the second reaction solution of Cys-targeted anti-tumor polypeptide;

[0014] S3: After mixing the first reaction solution of Cys-9-aminocamptothecin and the second reaction solution of Cys-targeted anti-tumor polypeptide evenly, continuously introduce oxygen and stir at 15 - 25 °C for 2 - 3 h to oxidize -SH in Cys-9-aminocamptothecin and Cys-targeted anti-tumor polypeptide to form -S-S- for coupling, and then incubate at room temperature with shaking at 25 °C for 2 - 10 h, remove the organic solvent by rotary evaporation under reduced pressure and after purification, the camptothecin polypeptide anti-tumor drug conjugate is obtained.

[0015] Further, the condensing agent EDC / HOBt is composed of EDC and HOBt mixed according to a mass ratio of 1:(0.6 - 1).

[0016] Further, in S1, the dosage ratio of 9-aminocamptothecin, 1,4-dioxane solvent, cysteine, and condensing agent EDC / HOBt is (0.02 - 0.2) mmol: 25 mL: (0.02 - 0.2) mmol: (0.5 - 5) mg.

[0017] Further, in S2, the dosage ratio of the targeted anti-tumor polypeptide, tetrahydrofuran solvent, cysteine, and condensing agent EDC / HOBt is (0.02 - 0.2) mmol: 25 mL: (0.02 - 0.2) mmol: (0.5 - 5) mg.

[0018] Further, in S3, the volume ratio of the first reaction solution of Cys-9-aminocamptothecin to the second reaction solution of Cys-targeted anti-tumor polypeptide is 1:1.

[0019] Further, the feeding rate of oxygen is 1 - 2.5 L / min.

[0020] Use of the camptothecin polypeptide anti-tumor drug conjugate prepared by the described preparation method in the preparation of anti-cancer drugs.

[0021] Advantages of the present invention:

[0022] For the first time, the present invention uses cysteine as an intermediate linker, and uses amidation reaction to graft and bond cysteine onto 9-aminocamptothecin and polypeptide HYD-PEP06 respectively, and then oxidizes to form disulfide bonds for coupling. The synthesized anti-tumor drug conjugate can specifically target and act on tumor sites and tumor cells, enabling drug molecules to highly accumulate at the tumor site, having high tumor targeting and retention, achieving targeted precision chemotherapy, reducing the toxic and side effects on the body. At the same time, the conjugate form effectively improves the stability of 9-aminocamptothecin and prolongs the blood circulation half-life of the drug, continuously exerting anti-tumor efficacy. Among them, the repeated Arg-Gly-Asp (RGD) motif at the N-terminus of the polypeptide HYD-PEP06 specifically binds to the integrin of tumor-associated vascular endothelial cells, inhibiting tumor angiogenesis, tumor proliferation, nutrient absorption and metabolism, etc. Description of the Drawings

[0023] Figure 1 It is a flow chart of the preparation method of the camptothecin polypeptide anti-tumor drug conjugate of the present invention;

[0024] Figure 2This is the process flow chart for the synthesis of the camptothecin polypeptide anti-tumor drug conjugate of the present invention. In the figure, R represents the amino acid sequence of the polypeptide HYD-PEP06: Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met. Detailed implementation manners

[0025] The following further elaborates on the present invention in conjunction with embodiments, enabling those skilled in the art to implement it with reference to the text of the specification.

[0026] The present invention provides a camptothecin polypeptide anti-tumor drug conjugate of an embodiment: using cysteine as an intermediate linker, cysteine is grafted onto 9-aminocamptothecin and the polypeptide HYD-PEP06 by amidation reaction, and then oxidized to form a disulfide bond to conjugate 9-aminocamptothecin and the targeted anti-tumor polypeptide; the amino acid sequence of the polypeptide HYD-PEP06 is Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met.

[0027] The structural formula of the anti-tumor drug conjugate is shown in Formula I:

[0028]

[0029] Among them, R is Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met.

[0030] The preparation method of the camptothecin polypeptide anti-tumor drug conjugate of this embodiment includes the following steps:

[0031] S1: Mix EDC and HOBt evenly according to a mass ratio of 1:(0.6 - 1) to obtain the condensing agent EDC / HOBt;

[0032] S2: Add 9-aminocamptothecin to 1,4-dioxane solvent. After stirring and dissolving, add cysteine and condensing agent EDC / HOBt, and react under magnetic stirring at 20 - 30 °C for 3 - 5 h to obtain the first reaction solution of Cys-9-aminocamptothecin. The dosage ratio of 9-aminocamptothecin, 1,4-dioxane solvent, cysteine, and condensing agent EDC / HOBt is (0.02 - 0.2) mmol: 25 mL: (0.02 - 0.2) mmol: (0.5 - 5) mg;

[0033] S3: Add polypeptide HYD-PEP06 to tetrahydrofuran solvent. After stirring and dissolving, add cysteine and condensing agent EDC / HOBt, and react under magnetic stirring at 20 - 30 °C for 3 - 5 h to obtain the second reaction solution of Cys-targeted anti-tumor polypeptide. The dosage ratio of polypeptide HYD-PEP06, tetrahydrofuran solvent, cysteine, and condensing agent EDC / HOBt is (0.02 - 0.2) mmol: 25 mL: (0.02 - 0.2) mmol: (0.5 - 5) mg;

[0034] S4: Mix the first reaction solution of Cys-9-aminocamptothecin and the second reaction solution of Cys-targeted anti-tumor polypeptide evenly according to a volume ratio of 1:1, and at 15 - 25 °C, continuously introduce oxygen at a rate of 1 - 2.5 L / min and stir and react for 2 - 3 h to oxidize -SH in Cys-9-aminocamptothecin and Cys-targeted anti-tumor polypeptide to form -S-S- for coupling. Then incubate at room temperature with shaking at 25 °C for 2 - 10 h, remove the organic solvent by rotary evaporation under reduced pressure and after purification, the camptothecin polypeptide anti-tumor drug conjugate is obtained.

[0035] Application of the camptothecin polypeptide anti-tumor drug conjugate prepared by the method of this example in the preparation of cancer therapeutic drugs.

[0036] Example 1

[0037] A preparation method of a camptothecin polypeptide anti-tumor drug conjugate, comprising the following steps:

[0038] S1: Mix EDC and HOBt evenly according to a mass ratio of 1:0.6 to obtain the condensing agent EDC / HOBt;

[0039] S2: Add 0.02 mmol of 9-aminocamptothecin to 25 mL of 1,4-dioxane solvent. After stirring and dissolving, add 0.02 mmol of cysteine and 0.5 mg of condensing agent EDC / HOBt, and react under magnetic stirring at 20 °C for 3 h to obtain the first reaction solution of Cys-9-aminocamptothecin;

[0040] S3: Add 0.02 mmol of polypeptide HYD-PEP06 into 25 mL of tetrahydrofuran solvent. After stirring and dissolving, add 0.02 mmol of cysteine and 0.5 mg of condensing agent EDC / HOBt, and react with magnetic stirring at 20 °C for 3 h to obtain the second reaction solution of Cys-targeted anti-tumor polypeptide; the amino acid sequence of the polypeptide HYD-PEP06 is Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met;

[0041] S4: Mix the first reaction solution of Cys-9-aminocamptothecin and the second reaction solution of Cys-targeted anti-tumor polypeptide evenly according to the volume ratio of 1:1. At 15 °C, continuously introduce oxygen at a rate of 1 / min and stir and react for 2 h, then incubate with shaking at room temperature of 25 °C for 2 h. Remove the organic solvent by rotary evaporation under reduced pressure and after purification, the camptothecin polypeptide anti-tumor drug conjugate is obtained.

[0042] Example 2

[0043] A preparation method of a camptothecin polypeptide anti-tumor drug conjugate, comprising the following steps:

[0044] S1: Mix EDC and HOBt evenly according to the mass ratio of 1:0.8 to obtain the condensing agent EDC / HOBt;

[0045] S2: Add 0.04 mmol of 9-aminocamptothecin into 25 mL of 1,4-dioxane solvent. After stirring and dissolving, add 0.04 mmol of cysteine and 0.8 mg of condensing agent EDC / HOBt, and react with magnetic stirring at 20 °C for 4 h to obtain the first reaction solution of Cys-9-aminocamptothecin;

[0046] S3: Add 0.04 mmol of polypeptide HYD-PEP06 into 25 mL of tetrahydrofuran solvent. After stirring and dissolving, add 0.04 mmol of cysteine and 0.8 mg of condensing agent EDC / HOBt, and react with magnetic stirring at 20 °C for 4 h to obtain the second reaction solution of Cys-targeted anti-tumor polypeptide; the amino acid sequence of the polypeptide HYD-PEP06 is Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met;

[0047] S4: After uniformly mixing the first reaction solution of Cys-9-aminocamptothecin and the second reaction solution of Cys-targeted anti-tumor polypeptide at a volume ratio of 1:1, at 20 °C, oxygen is continuously introduced at a rate of 1.5 L / min and the reaction is stirred for 2 h, then incubated with shaking at room temperature at 25 °C for 4 h, and the organic solvent is removed by rotary evaporation under reduced pressure and purified to obtain the camptothecin polypeptide anti-tumor drug conjugate.

[0048] Example 3

[0049] A preparation method of a camptothecin polypeptide anti-tumor drug conjugate, comprising the following steps:

[0050] S1: Mix EDC and HOBt uniformly at a mass ratio of 1:0.8 to obtain the condensing agent EDC / HOBt;

[0051] S2: Add 0.12 mmol of 9-aminocamptothecin to 25 mL of 1,4-dioxane solvent, stir to dissolve, then add 0.12 mmol of cysteine and 2.5 mg of the condensing agent EDC / HOBt, and react with magnetic stirring at 25 °C for 4 h to obtain the first reaction solution of Cys-9-aminocamptothecin;

[0052] S3: Add 0.12 mmol of the polypeptide HYD-PEP06 to 25 mL of tetrahydrofuran solvent, stir to dissolve, then add 0.12 mmol of cysteine and 2.5 mg of the condensing agent EDC / HOBt, and react with magnetic stirring at 25 °C for 4 h to obtain the second reaction solution of Cys-targeted anti-tumor polypeptide; the amino acid sequence of the polypeptide HYD-PEP06 is Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met;

[0053] S4: After uniformly mixing the first reaction solution of Cys-9-aminocamptothecin and the second reaction solution of Cys-targeted anti-tumor polypeptide at a volume ratio of 1:1, at 20 °C, oxygen is continuously introduced at a rate of 2 L / min and the reaction is stirred for 2.5 h, then incubated with shaking at room temperature at 25 °C for 6 h, and the organic solvent is removed by rotary evaporation under reduced pressure and purified to obtain the camptothecin polypeptide anti-tumor drug conjugate.

[0054] Example 4

[0055] A preparation method of a camptothecin polypeptide anti-tumor drug conjugate, comprising the following steps:

[0056] S1: Mix EDC and HOBt uniformly at a mass ratio of 1:0.9 to obtain the condensing agent EDC / HOBt;

[0057] S2: Add 0.15 mmol of 9-aminocamptothecin into 25 mL of 1,4-dioxane solvent. After stirring and dissolving, add 0.15 mmol of cysteine and 0.35 mg of condensing agent EDC / HOBt, and react under magnetic stirring at 28 °C for 4 h to obtain the first reaction solution of Cys-9-aminocamptothecin;

[0058] S3: Add 0.15 mmol of polypeptide HYD-PEP06 into 25 mL of tetrahydrofuran solvent. After stirring and dissolving, add 0.15 mmol of cysteine and 0.35 mg of condensing agent EDC / HOBt, and react under magnetic stirring at 28 °C for 4 h to obtain the second reaction solution of Cys-targeted anti-tumor polypeptide; the amino acid sequence of the polypeptide HYD-PEP06 is Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met;

[0059] S4: Mix the first reaction solution of Cys-9-aminocamptothecin and the second reaction solution of Cys-targeted anti-tumor polypeptide evenly according to the volume ratio of 1:1. At 25 °C, continuously introduce oxygen at a rate of 2.0 L / min and stir and react for 3 h, then incubate at room temperature with shaking at 25 °C for 8 h. Remove the organic solvent by rotary evaporation under reduced pressure and purify to obtain the camptothecin polypeptide anti-tumor drug conjugate.

[0060] Example 5

[0061] A preparation method of a camptothecin polypeptide anti-tumor drug conjugate, comprising the following steps:

[0062] S1: Mix EDC and HOBt evenly according to the mass ratio of 1:1 to obtain the condensing agent EDC / HOBt;

[0063] S2: Add 0.2 mmol of 9-aminocamptothecin into 25 mL of 1,4-dioxane solvent. After stirring and dissolving, add 0.2 mmol of cysteine and 5 mg of condensing agent EDC / HOBt, and react under magnetic stirring at 30 °C for 5 h to obtain the first reaction solution of Cys-9-aminocamptothecin;

[0064] S3: Add 0.2 mmol of polypeptide HYD-PEP06 into 25 mL of tetrahydrofuran solvent. After stirring and dissolving, add 0.2 mmol of cysteine and 5 mg of condensing agent EDC / HOBt, and react with magnetic stirring at 30 °C for 5 h to obtain the second reaction solution of Cys-targeted anti-tumor polypeptide; the amino acid sequence of the polypeptide HYD-PEP06 is Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met;

[0065] S4: Mix the first reaction solution of Cys-9-aminocamptothecin and the second reaction solution of Cys-targeted anti-tumor polypeptide evenly according to the volume ratio of 1:1. At 25 °C, continuously introduce oxygen at a rate of 2.5 L / min and stir and react for 3 h, then incubate at room temperature with shaking at 25 °C for 10 h. Remove the organic solvent by rotary evaporation under reduced pressure and purify to obtain the camptothecin polypeptide anti-tumor drug conjugate.

[0066] Using 9-aminocamptothecin as a comparative example, the tumor inhibition rates of Examples 1-5 and the comparative example were measured according to the following method:

[0067] Subcutaneously inject a suspension of Lewis lung cancer cells into the back of the right forelimb of 70 female Kunming mice weighing 50 ± 1 g to establish a transplanted tumor model. Randomly divide the tumor-bearing mice into 7 groups at 70 mice / group. Administer the samples of Examples 1-5 and the comparative example and normal saline to the tumor-bearing mice in groups 1-7 via the tail vein once, and administer via the tail vein once every 3 days for 3 treatments. The administration dose is 3.0 mg / kg. Sacrifice the mice on the 3rd day after the 3rd treatment, dissect the tumor tissue, weigh it, and calculate the tumor inhibition rate according to 100% × (1 - tumor weight after treatment with each example or comparative example / tumor weight after treatment with normal saline). The test results are shown in the following table:

[0068] Drug half-life / % Tumor inhibition rate / % Example 1 4.8 75.6 Example 2 5.0 76.1 Example 3 5.0 78.8 Example 4 4.9 78.4 Example 5 5.2 79.2 Comparative example 1.6 35.7

[0069] As can be seen from the above table, the camptothecin polypeptide anti-tumor drug conjugates prepared in Examples 1-5 are far superior to the pure camptothecin of the comparative example in terms of blood circulation half-life and anti-tumor efficacy, proving that the drug conjugate prepared by the method of the present invention has high stability and stronger anti-tumor efficacy.

[0070] In Examples 1-5, for the first time, cysteine was used as an intermediate linker. Through amidation reaction, cysteine was grafted and bonded onto 9-aminocamptothecin and polypeptide HYD-PEP06 respectively, and then oxidized to form disulfide bonds for coupling. The synthesized anti-tumor drug conjugate can specifically target and act on tumor sites and tumor cells, enabling the drug molecules to highly accumulate at the tumor sites, achieving targeted and precise chemotherapy, reducing the toxic and side effects on the body. At the same time, the conjugate form effectively improves the stability of 9-aminocamptothecin, prolongs the blood circulation half-life of the drug, and continuously exerts anti-tumor efficacy. Among them, the repeated Arg-Gly-Asp (RGD) motif at the N-terminus of the polypeptide HYD-PEP06 specifically binds to the integrin of tumor-associated vascular endothelial cells, inhibiting tumor angiogenesis, tumor proliferation, nutrient absorption and metabolism, etc.

[0071] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details.

Claims

1. A camptothecin polypeptide anti-tumor drug conjugate, characterized in that: Using cysteine as an intermediate linker, cysteine is grafted onto 9-aminocamptothecin and the anti-tumor polypeptide by amidation reaction, and then oxidized to form a disulfide bond to couple 9-aminocamptothecin and the anti-tumor polypeptide; The anti-tumor polypeptide is polypeptide HYD-PEP06, and its amino acid sequence is Arg-Gly-Asp-Arg-Gly-Asp-Met-His-Ser-His-Arg-Asp-Phe-Gln-Pro-Val-Leu-His-Leu-Val-Ala-Leu-Asn-Ser-Pro-Leu-Ser-Gly-Gly-Met; The structural formula of the anti-tumor drug conjugate is shown in Formula I: 。 2. A preparation method of the camptothecin polypeptide anti-tumor drug conjugate according to claim 1, characterized in that it includes the following steps: S1: Add 9-aminocamptothecin to a 1,4-dioxane solvent, stir to dissolve it, then add cysteine and the condensing agent EDC / HOBt, and carry out a magnetic stirring reaction at 20-30 °C for 3-5 h to obtain the first reaction solution of Cys-9-aminocamptothecin; S2: Add the anti-tumor polypeptide to a tetrahydrofuran solvent, stir to dissolve it, then add cysteine and the condensing agent EDC / HOBt, and carry out a magnetic stirring reaction at 20-30 °C for 3-5 h to obtain the second reaction solution of Cys-anti-tumor polypeptide; S3: After mixing the first reaction solution of Cys-9-aminocamptothecin and the second reaction solution of Cys-anti-tumor polypeptide evenly, continuously introduce oxygen and stir at 15-25 °C for 2-3 h to oxidize -SH in Cys-9-aminocamptothecin and Cys-anti-tumor polypeptide to form -S-S- for coupling, and then incubate at room temperature with shaking at 25 °C for 2-10 h, remove the organic solvent by rotary evaporation under reduced pressure and purify it to obtain the camptothecin polypeptide anti-tumor drug conjugate.

3. The preparation method of the camptothecin polypeptide anti-tumor drug conjugate according to claim 2, characterized in that the condensing agent EDC / HOBt is composed of EDC and HOBt mixed in a mass ratio of 1:(0.6-1).

4. The preparation method of the camptothecin polypeptide anti-tumor drug conjugate according to claim 2, characterized in that in S1, the dosage ratio of 9-aminocamptothecin, 1,4-dioxane solvent, cysteine, and the condensing agent EDC / HOBt is (0.02-0.2) mmol:25 mL:(0.02-0.2) mmol:(0.5-5) mg.

5. The preparation method of the camptothecin polypeptide anti-tumor drug conjugate according to claim 2, characterized in that in S2, the dosage ratio of the anti-tumor polypeptide, tetrahydrofuran solvent, cysteine, and the condensing agent EDC / HOBt is (0.02-0.2) mmol:25 mL:(0.02-0.2) mmol:(0.5-5) mg.

6. The preparation method of the camptothecin polypeptide anti-tumor drug conjugate according to claim 2, It is characterized in that In S3, the volume ratio of the first reaction solution of Cys-9-aminocamptothecin to the second reaction solution of Cys-targeted anti-tumor polypeptide is 1:

1.

7. The method for preparing a camptothecin polypeptide anti-tumor drug conjugate according to claim 2, It is characterized in that The introduction rate of the oxygen is 1-2.5 L / min.

8. Use of a camptothecin polypeptide anti-tumor drug conjugate prepared by the preparation method according to any one of claims 2-7 in the preparation of a drug for treating cancer.

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