A polypeptide targeting and destroying lipid droplets and its application in preparation of anti-tumor drugs

Abstract

The present application relates to a kind of polypeptide for targeting destruction lipid droplet and its application in preparation of antitumor drugs, belong to biological medicine manufacturing technical field.To solve the problem that existing antitumor drugs for tumor lipid droplet cannot effectively inhibit tumor cell immune escape while destroying lipid droplet, the present application provides a kind of polypeptide for targeting destruction lipid droplet, including sequentially connected PLIN2 targeting peptide segment, self-assembly peptide segment, enzyme response peptide segment and HLA-E targeting peptide segment.The present application constructs the polypeptide for targeting destruction lipid droplet based on double targeting strategy, can target the PLIN2 protein on the surface of lipid droplet;Self-assembly peptide segment can form nanofiber structure on the surface of lipid droplet, destroy lipid droplet structure and function, cause endoplasmic reticulum stress, cause tumor cell immunogenic death.HLA-E targeting peptide segment released by polypeptide enzyme cutting can specifically target HLA-E on the membrane of tumor cell, block NKG2A-HLA-E pathway, effectively inhibit tumor cell immune escape.

Description

Technical Field

[0001] This invention belongs to the field of biopharmaceutical manufacturing technology, and in particular relates to a polypeptide that targets and destroys lipid droplets and its application in the preparation of antitumor drugs. Background Technology

[0002] Lipid droplets are dynamic lipid storage organelles widely distributed within cells, composed of triglycerides and cholesterol esters encapsulated by a single phospholipid membrane. In recent years, research has revealed that lipid droplets play a crucial role in tumor metabolic reprogramming, metastasis, treatment resistance, and immune escape, making them a new focus of cancer research. In the energy metabolism of tumor cells, fatty acids stored in lipid droplets meet the energy demands of rapid proliferation. Under hypoxic or nutrient-deprived conditions, lipid droplets provide free fatty acids through lipolysis to supply energy for tumor physiological activities. Simultaneously, lipid droplets act as buffers against lipid peroxidation, preventing ferroptosis in tumor cells caused by lipid peroxidation.

[0003] Disruption of lipid droplet structure in tumor cells leads to the release of large amounts of free fatty acids. These free fatty acids induce endoplasmic reticulum stress by disrupting the structure of the endoplasmic reticulum and calcium ion homeostasis in tumor cells. Endoplasmic reticulum stress can trigger immunogenic death of tumor cells, transforming them from non-immunogenic to immunogenic, thereby mediating the body's anti-tumor immune response.

[0004] However, to mediate immune escape, tumor cells upregulate the expression of HLA-E molecules on their cell surface, enabling them to bind to the inhibitory receptor NKG2A on the surface of NK cells and some T cells, forming the NKG2A-HLA-E axis. This inhibits the activity of NK cells and T cells, leading to a weakened response to tumor cell immunogenic cell death. This means that even if tumor cells undergo immunogenic cell death, immune cells may not be able to effectively recognize and eliminate these dead tumor cells, leading to tumor recurrence, metastasis, and immune escape, thus affecting treatment efficacy.

[0005] PLIN2, an important member of the lipid droplet coating protein family, is mainly located on the lipid droplet membrane and plays a central role in lipid droplet formation, stability, and metabolic regulation. Its expression level is closely related to the number of intracellular lipid droplets and is abnormally upregulated in various metabolic diseases and tumors. Some studies have shown that knocking down PLIN2 reduces lipid droplet stability, making them more prone to rupture. However, this method is technically challenging and has a single mechanism of action, failing to effectively address the immune escape problem of tumor cells while simultaneously disrupting lipid droplets. Summary of the Invention

[0006] To address the problem that existing antitumor drugs targeting tumor lipid droplets cannot effectively inhibit tumor cell immune escape while destroying lipid droplets, this invention provides a polypeptide that targets and destroys lipid droplets and its application in the preparation of antitumor drugs. This polypeptide induces endoplasmic reticulum stress by specifically destroying tumor cell lipid droplets, thereby inducing immunogenic death of tumor cells. At the same time, it enhances the activity of NK cells and T cells by blocking the NKG2A-HLA-E axis, further promoting tumor immune killing and improving the efficacy of immunotherapy.

[0007] The technical solution of this invention:

[0008] A polypeptide targeting and disrupting lipid droplets comprises a PLIN2 targeting peptide, a self-assembled peptide, an enzyme-responsive peptide, and an HLA-E targeting peptide connected in sequence. The amino acid sequence of the PLIN2 targeting peptide is shown in SEQ ID No. 1; the amino acid sequence of the self-assembled peptide is shown in SEQ ID No. 2; the amino acid sequence of the enzyme-responsive peptide is shown in SEQ ID No. 3; and the amino acid sequence of the HLA-E targeting peptide is shown in SEQ ID No. 4.

[0009] Furthermore, the molecular structure of the polypeptide that targets and disrupts lipid droplets is shown in Formula I:

[0010]

[0011] Formula I.

[0012] Furthermore, the preparation method of the peptide that targets and destroys lipid droplets adopts a peptide solid-phase synthesis method, in which the required amino acids in the PLIN2 targeting peptide, self-assembled peptide, enzyme-responsive peptide and HLA-E targeting peptide sequence are sequentially linked from the C-terminus to the N-terminus via amide bonds to obtain an artificially synthesized peptide that targets and destroys lipid droplets.

[0013] Application of a peptide that targets and disrupts lipid droplets in the preparation of antitumor drugs.

[0014] Furthermore, the tumors include kidney cancer, breast cancer, and liver cancer.

[0015] Furthermore, the antitumor drug uses a polypeptide that targets and destroys lipid droplets as its sole active ingredient or one of its active ingredients.

[0016] Furthermore, the antitumor drug is a non-gastrointestinal dosage form, specifically an injectable dosage form.

[0017] Furthermore, the antitumor drug can specifically recognize and bind to the PLIN2 protein on the surface of lipid droplets, thereby disrupting the structure and function of the lipid droplets.

[0018] Furthermore, the antitumor drug specifically recognizes and binds to the HLA-E protein on the surface of tumor cells, blocking the NKG2A-HLA-E pathway and inhibiting immune escape.

[0019] The beneficial effects of this invention are:

[0020] This invention constructs a peptide-targeting system for targeting and destroying lipid droplets based on a dual-targeting strategy. Among the peptides targeting and destroying lipid droplets, the PLIN2-targeting peptide has lipid droplet-specific targeting function, accurately recognizing and binding to the PLIN2 protein on the surface of lipid droplets, achieving in-situ enrichment of the peptide in the tumor; the self-assembling peptide can form nanofiber structures on the surface of lipid droplets, remaining there for a long time, disrupting the structure and function of lipid droplets, leading to endoplasmic reticulum stress in tumor cells and causing immunogenic cell death; the enzyme-responsive peptide can be specifically cleaved by matrix metalloproteinases (MMP-2) in the tumor microenvironment, releasing the HLA-E-targeting peptide from the peptide; the HLA-E-targeting peptide can specifically target HLA-E on the tumor cell membrane, blocking the NKG2A-HLA-E pathway, enhancing NK cell and T cell activity, effectively inhibiting tumor cell immune escape, and promoting immune killing of tumors.

[0021] This invention provides a combined treatment regimen that utilizes peptides to target PLIN2 and disrupt lipid droplets while simultaneously blocking the NKG2A-HLA-E pathway to enhance anti-tumor immunity. This regimen has broad-spectrum anti-tumor effects and demonstrates promising prospects for clinical application. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the molecular structure of the polypeptide LTN that targets and destroys lipid droplets in Example 1;

[0023] Figure 2 This is a comparison of fluorescence signals at different administration times in the mouse models injected with LTN and LTN-C in Example 2;

[0024] Figure 3 The images show Oil Red staining and BODIPY staining of Renca cells co-cultured with LTN and LTN-C in Example 3. A is the Oil Red staining image, and B is the BODIPY staining image.

[0025] Figure 4 These are laser confocal microscopy images of Renca renal cell carcinoma cells co-cultured with LTN and LTN-C in Example 4 after ER-Tracker Red staining.

[0026] Figure 5 The images show staining results of migration and invasion assays of Renca renal cell carcinoma cells after LTN and LTN-C treatment in Example 5. The upper layer shows the staining results of the migration assay, and the lower layer shows the staining results of the invasion assay.

[0027] Figure 6 This is a comparison of ATP content in the supernatant of Renca renal cell carcinoma cells after LTN and LTN-C treatment in Example 6.

[0028] Figure 7 The image shows DAPI staining of Renca renal cell carcinoma cells after LTN and LTN-C treatment in Example 6, with A representing CRT detection and B representing HMGB1 detection.

[0029] Figure 8 The CD107a cells in T cells and NK cells treated with LTN and LTN-C in Example 7 + Cell proportion comparison diagram, A represents CD8 cells, a representative T cell. + Cells, B is the representative cell of NK cells CD56 + cell;

[0030] Figure 9 This is a comparison of cell viability of mouse breast cancer cells and liver cancer cells after LTN and LTN-C treatment in Example 8. A represents breast cancer cells, and B represents liver cancer cells. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention. In the following embodiments, the process equipment or apparatus not specifically specified are all conventional equipment or apparatus in the art. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commercially available; unless otherwise specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0032] Example 1

[0033] This embodiment provides a polypeptide that targets and disrupts lipid droplets and its preparation method.

[0034] In this embodiment, the polypeptide LTN that targets and disrupts lipid droplets consists of a PLIN2-targeting peptide, a self-assembled peptide, an enzyme-responsive peptide, and an HLA-E-targeting peptide connected in sequence. A schematic diagram of the molecular structure is shown below. Figure 1 As shown in SEQ ID No. 1, the amino acid sequence of the PLIN2 targeting peptide is ACNIYGAQGC; the amino acid sequence of the self-assembled peptide is KLVFF; the amino acid sequence of the enzyme-responsive peptide is GPLGVRG; and the amino acid sequence of the HLA-E targeting peptide is VMPLSAPTL.

[0035] Among the LTN peptides that target and destroy lipid droplets, the PLIN2 targeting peptide has a lipid droplet-specific targeting function; the self-assembling peptide can form nanofiber structures on the surface of lipid droplets and remain on the surface of lipid droplets for a long time, destroying the structure and function of lipid droplets, leading to endoplasmic reticulum stress in tumor cells and causing immunogenic death of tumor cells; the enzyme-responsive peptide can be specifically cleaved by matrix metalloproteinases (MMP-2) in the tumor microenvironment, releasing the HLA-E targeting peptide from the peptide. The HLA-E targeting peptide can specifically target HLA-E on the tumor cell membrane, block the NKG2A-HLA-E pathway, enhance the activity of NK cells and T cells, and promote immune killing against tumors.

[0036] The targeted lipid droplet-destroying peptide LTN provided in this embodiment is synthesized using conventional solid-phase peptide synthesis methods in the art, derived from C

[0037] The desired amino acids in the PLIN2-targeting peptide, self-assembled peptide, enzyme-responsive peptide, and HLA-E-targeting peptide sequence are sequentially linked from end to N-terminus via amide bonds to obtain the artificially synthesized lipid droplet-destroying polypeptide LTN, whose molecular structure is shown in Formula I:

[0038]

[0039] Formula I.

[0040] This embodiment also provides a control peptide LTN-C that is non-mutagenic and self-assembled, comprising a PLIN2-targeting peptide, a non-mutagenic peptide, an enzyme-responsive peptide, and an HLA-E-targeting peptide connected in sequence; wherein the amino acid sequence of the PLIN2-targeting peptide is shown in SEQ ID No. 1, specifically ACNIYGAQGC; the amino acid sequence of the non-mutagenic peptide is shown in SEQ ID No. 5, specifically KAAGG; the amino acid sequence of the enzyme-responsive peptide is shown in SEQ ID No. 3, specifically GPLLGVRG; and the amino acid sequence of the HLA-E-targeting peptide is shown in SEQ ID No. 4, specifically VMPLSAPTL.

[0041] The control peptide LTN-C was synthesized using conventional solid-phase peptide synthesis methods in the art. The required amino acids from the PLIN2 targeting peptide, the immutable peptide, the enzyme-responsive peptide, and the HLA-E targeting peptide were sequentially linked from the C-terminus to the N-terminus via amide bonds, resulting in the artificially synthesized control peptide LTN-C. Its molecular structure is shown in Figure II.

[0042]

[0043] Formula II.

[0044] Example 2

[0045] This embodiment demonstrates that the peptide LTN, which targets and destroys lipid droplets, has the ability to target in vivo and remain in tumors.

[0046] To evaluate the in vivo targeting and intratumoral retention capabilities of the lipid droplet-targeting peptide LTN and the control peptide LTN-C obtained in Example 1, a mouse tumor model was established in this example.

[0047] Four-week-old female BALB / c mice were selected for in vivo animal experiments. Renca renal cell carcinoma cells (5 × 10⁻⁶) in good condition and exhibiting logarithmic growth were cultured. 6 400 × 10⁻⁶ cells (200 μL PBS) were subcutaneously injected into the right buttock of BALB / c nude mice, and tumor growth in the mice was subsequently observed. After successful establishment of the small animal model, LTN and LTN-C were injected into the tail vein of mice, with an injection volume of 200 µL each. 6 M, using in vivo imaging systems (IVIS) to capture fluorescence signals at 4h, 8h, 12h, 24h, 48h and 72h after injection.

[0048] The results are as follows Figure 2 As shown, LTN is mainly distributed at the tumor site, indicating that it can precisely target mouse tumors in vivo and remain there for a long time. LTN-C can also precisely target tumors, but its retention time in vivo is shorter. This suggests that the PLIN2-targeting peptides in LTN and LTN-C have good PLIN2 targeting properties, enabling the drug to accumulate on the surface of lipid droplets in tumor cells. The self-assembling peptides in LTN, by forming nanofiber structures on the lipid droplet surface, immobilize the peptides on the lipid droplet surface, thus prolonging the drug retention time.

[0049] Example 3

[0050] This embodiment demonstrates that the peptide LTN, which targets and destroys lipid droplets, has the effect of destroying lipid droplets in tumor cells.

[0051] To evaluate the effect of the lipid droplet-targeting peptide LTN on lipid droplets in tumor cells, healthy, logarithmically growing Renca renal cell carcinoma cells were seeded in confocal cell culture dishes. After cell adhesion, 20 μmol / L LTN, LTN-C, and PBS solutions (as described in Example 1) were added and co-cultured for one day. The cell culture medium was then removed, and the cells were fixed with Oil Red O fixative, washed twice with distilled water, rinsed with 60% isopropanol, and then stained with freshly prepared Oil Red O staining solution. Mayer hematoxylin staining solution was used to counterstain the nuclei, followed by incubation with Oil Red O buffer until blue staining returned. The cells were then observed under a microscope. For BODIPY staining, the cells to be tested were removed, washed twice with PBS, and then fixed with 4% paraformaldehyde fixative at room temperature for 10-15 minutes. After fixation, the cells were washed 1-2 times with PBS. The PBS was removed, and an appropriate volume of staining solution was added. The cells were incubated at room temperature in the dark for 10-20 minutes, followed by washing twice with PBS. When observing the cells under a fluorescence microscope, excitation at approximately 488 nm was used to observe green fluorescence.

[0052] The results are as follows Figure 3 As shown, compared with the PBS control, LTN-C had no significant effect on lipid droplets in tumor cells, but after LTN treatment, the number of lipid droplets in tumor cells was significantly reduced, and the fluorescence decreased. This demonstrates that the peptide LTN, which targets and disrupts lipid droplets, has a destructive effect on lipid droplets in tumor cells.

[0053] Example 4

[0054] This embodiment demonstrates that the peptide LTN, which targets and destroys lipid droplets, can induce endoplasmic reticulum stress in tumor cells.

[0055] To evaluate the effect of the lipid droplet-targeting peptide LTN on endoplasmic reticulum stress in tumor cells, healthy, logarithmically growing Renca renal cell carcinoma cells were seeded in confocal cell culture dishes. After cell attachment, 20 μmol / L LTN, LTN-C, and PBS solutions (as described in Example 1) were added and co-cultured for 1 day. Subsequently, ER-Tracker Red staining working solution pre-incubated at 37°C was added and co-incubated with the cells for 30 minutes. The ER-Tracker Red staining working solution was removed, and the cells were washed 1-2 times with cell culture medium. The cells were then observed using a laser confocal microscope.

[0056] The results are as follows Figure 4 As shown, compared with PBS control and LTN-C, the endoplasmic reticulum fluorescence signal of tumor cells was significantly enhanced after LTN treatment, indicating that LTN induced endoplasmic reticulum stress in tumor cells.

[0057] Example 5

[0058] This embodiment demonstrates that the peptide LTN, which targets and destroys lipid droplets, has the effect of inhibiting tumor cell migration and invasion.

[0059] To evaluate the effect of the lipid droplet-targeting peptide LTN on tumor cell migration and invasion, in an invasion assay, matrix gel was laid in the upper chamber of a Transwell chamber, and healthy, logarithmically growing Renca renal cell carcinoma cells were introduced at 10 cells per well. 5 Cells were seeded at a density of 10 μmol / L in the upper chamber of a Transwell containing 20 μmol / L LTN, LTN-C, and PBS solutions obtained in Example 1, and 750 µL of 1640 complete medium was added to the lower chamber. After culturing at 37°C for 48 hours, the invaded cells in the lower layer were stained and counted. In the migration assay, Transwell inserts were placed in 24-well plates, and serum-free medium and tumor cells were directly added to each Transwell upper chamber. Simultaneously, 20 μmol / L LTN, LTN-C, and PBS solutions obtained in Example 1 were added, and 750 µL of 1640 complete medium was added to the lower chamber. After culturing at 37°C for 48 hours, the invaded cells in the lower layer were stained and counted.

[0060] The results are as follows Figure 5 As shown, compared with PBS control and LTN-C, LTN treatment reduced the number of migrating and invading tumor cells. This indicates that LTN disrupts the lipid droplets of tumor cells, depriving them of the energy supply needed for migration and invasion, thus inhibiting tumor cell migration and invasion.

[0061] Example 6

[0062] This embodiment demonstrates that the peptide LTN, which targets and destroys lipid droplets, can trigger immunogenic cell death in tumor cells.

[0063] To evaluate the effect of the peptide LTN, which targets and disrupts lipid droplets, on immunogenic cell death in tumor cells, Renca renal cell carcinoma cells in good condition and exhibiting logarithmic growth were seeded in confocal cell culture dishes. After the cells adhered, LTN, LTN-C, and PBS solutions obtained in Example 1 were added and co-cultured for 1 day.

[0064] For ATP detection, cell supernatant was first collected and centrifuged at 12,000 rpm for 5 min at 4°C. The secreted ATP content was then measured using an ATP bioluminescence assay kit.

[0065] For CRT (calreticulin) and HMGB1 (high-mobility group box 1) assays, cells were first fixed with 4% paraformaldehyde for 15 min. They were then incubated with 0.3% Triton X-100 at room temperature for 5 min and washed. Cells were incubated with bovine serum albumin at 37°C for 1 h, followed by incubation with CRT or HMGB1 monoclonal antibodies, washed three times with PBS, and then incubated with fluorescent secondary antibody for 1 h. Finally, cells were stained with DAPI (4',6-diamidinyl-2-phenylindole) and observed using a laser confocal microscope.

[0066] The results are as follows Figure 6 and Figure 7 As shown, compared with the PBS control and LTN-C, LTN treatment resulted in the highest ATP content in the tumor cell supernatant, increased CRT expression in tumor cells, and decreased HMGB1 in the cell nucleus. This indicates that LTN treatment induced immunogenic cell death in tumor cells. LTN-C, however, failed to disrupt the structure and function of lipid droplets by forming nanofiber structures on the surface of lipid droplets through self-assembly, thus failing to induce endoplasmic reticulum stress and immunogenic cell death in tumor cells. This demonstrates that LTN can trigger immunogenic cell death in tumor cells by disrupting the structure and function of lipid droplets.

[0067] Example 7

[0068] This embodiment demonstrates that the peptide LTN, which targets and destroys lipid droplets, has the ability to enhance the activity of NK cells and T cells.

[0069] To evaluate the effect of the lipid droplet-targeting peptide LTN on the activity of NK and T cells, peripheral blood mononuclear cells (PBMCs) were seeded in 12-well plates and co-cultured with Renca renal cell carcinoma cells for 1 day in RPMI-1640 medium containing IL-12. Subsequently, 20 μmol / L of the LTN, LTN-C, and PBS solutions obtained in Example 1 were added to the medium. After 1 day, cells were collected and incubated with the respective antibodies in the dark for 30 min. After washing twice with PBS, the cells were resuspended in 300 μL of cold PBS for flow cytometry analysis.

[0070] The results are as follows Figure 8 As shown, CD107a + The cells are NK cells and CD8 cells. + CD8, a marker in the T cell activation process + The cell is a representative cell of T cells, CD56 + The cell is a representative cell of NK cells. CD107a + The increased proportion of cells indicates the presence of NK cells and CD8 cells. +T cell activity was correspondingly enhanced. Compared with the PBS control, NK cells and CD8 cells treated with LTN and LTN-C showed increased activity. + CD107a in T cells + The increasing percentage of cells indicates that both LTN and LTN-C can be cleaved by MMP-2 in tumor cells. The HLA-E targeting peptides released from the polypeptides can bind to HLA-E on the tumor cell membrane, blocking the NKG2A-HLA-E pathway and enhancing the activity of NK cells and T cells. Compared with LTN-C, LTN has a more significant effect on promoting the activity of immune cells. This is because LTN itself has the function of destroying tumor lipid droplets, which can induce immunogenic death of tumor cells and activate NK cells and T cells. The blocking of the NKG2A-HLA-E pathway further enhances the killing effect of immune cells on tumors.

[0071] Example 8

[0072] This embodiment demonstrates that the peptide LTN, which targets and disrupts lipid droplets, has an inhibitory effect on the cell viability of breast cancer cells and liver cancer cells.

[0073] Healthy, logarithmically growing mouse breast cancer cell line 4T1 and mouse hepatocellular carcinoma cell line H22 were used. After cell attachment, 20 μmol / L LTN, LTN-C, and PBS solutions (obtained in Example 1) were added, and the cells were co-cultured at 37°C. After 48 hours, the culture medium was discarded, and fresh culture medium containing 90 µL serum-free medium and 10 µL CCK-8 solution was added and cultured for another 4 hours. Finally, the absorbance was measured using a microplate reader.

[0074] The results are as follows Figure 9 As shown, compared with PBS control and LTN-C, the activity of breast cancer cells and liver cancer cells treated with LTN was significantly reduced. This demonstrates that the peptides targeting and disrupting lipid droplets provided by this invention have broad applicability in cancer treatment.

Claims

1. A polypeptide that targets disruption of lipid droplets, characterized in that, The peptide comprises, in sequence, a PLIN2-targeting peptide, a self-assembled peptide, an enzyme-responsive peptide, and an HLA-E-targeting peptide. The amino acid sequence of the PLIN2-targeting peptide is shown in SEQ ID No. 1; the amino acid sequence of the self-assembled peptide is shown in SEQ ID No. 2; the amino acid sequence of the enzyme-responsive peptide is shown in SEQ ID No. 3; and the amino acid sequence of the HLA-E-targeting peptide is shown in SEQ ID No.

4. The molecular structure of the peptide that targets and disrupts lipid droplets is shown in Formula I. ； Formula I.

2. The polypeptide for targeted disruption of lipid droplets according to claim 1, wherein, The method for preparing the peptide that targets and destroys lipid droplets employs a solid-phase peptide synthesis method. From the C-terminus to the N-terminus, the required amino acids in the PLIN2 targeting peptide, the self-assembled peptide, the enzyme-responsive peptide, and the HLA-E targeting peptide sequence are sequentially linked by amide bonds to obtain an artificially synthesized peptide that targets and destroys lipid droplets.

3. Use of a polypeptide for targeted disruption of lipid droplets according to claim 1 or 2 for the manufacture of a medicament for the treatment of a tumor, characterized in that, The tumors were selected from kidney cancer, breast cancer, and liver cancer.

4. The use of the polypeptide for targeted disruption of lipid droplets according to claim 3 in the preparation of an antitumor drug, characterized in that, The antitumor drug uses a polypeptide that targets and destroys lipid droplets as its sole active ingredient or one of its active ingredients.

5. The use of the polypeptide for targeted disruption of lipid droplets according to claim 4 for the preparation of an antitumor medicament, characterized in that, The antitumor drug is an injectable dosage form.

6. The use of the polypeptide for targeted disruption of lipid droplets according to claim 5 for the preparation of an antitumor medicament, characterized in that, The antitumor drug can specifically recognize and bind to the PLIN2 protein on the surface of lipid droplets, thereby disrupting the structure and function of the lipid droplets.

7. Use of the polypeptide for targeted disruption of lipid droplets according to claim 6 for the preparation of an antitumor medicament. The antitumor drug specifically recognizes and binds to the HLA-E protein on the surface of tumor cells, blocking the NKG2A-HLA-E pathway and inhibiting immune escape.

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