Application of SAA1 as ovarian cancer prognosis prediction serum marker and potential treatment target

Abstract

The invention relates to application of SAA1 as a biomarker in preparation of an ovarian cancer diagnostic kit. The invention further provides application of a reagent for detecting the content of SAA1 protein in preparation of the ovarian cancer diagnostic kit and application of an SAA1 inhibitor in preparation of a medicine for treating ovarian cancer. A series of experiments show that myeloid-derived suppressor cells (MDSCs) in peripheral blood and tumor tissues of an ovarian cancer patient are obviously gathered; sAA1 is elevated in an ovarian epithelial cancer (EOC) patient and is associated with a poor prognosis; sAA1 promotes proliferation of ovarian cancer cells in vitro; sAA1 released by ovarian cancer cells recruits MDSCs through a TLR2 / 4 receptor and promotes differentiation of the MDSCs. The invention innovatively provides a new treatment thought by deeply revealing the key effect of the SAA1-MDSCs in the ovarian cancer immunosuppression process, which undoubtedly has extremely important scientific significance and also shows huge value in clinical application.

Description

Technical Field

[0001] The present invention relates to the field of medical technology, and in particular to an application of SAA1 as a serum marker for predicting the prognosis of ovarian cancer and a potential therapeutic target. Background Art

[0002] The role of MDSC in tumor development: In recent decades, MDSC has been recognized as an indispensable cell population in the innate immune system, which has strong immunosuppressive activity in cancer and other pathological conditions. MDSC is a heterogeneous population of immature myeloid cells derived from bone marrow hematopoietic precursor cells. In healthy individuals, immature myeloid cells (IMCs) differentiate into granulocytes, macrophages and dendritic cells, and enter the corresponding organs and tissues to exert normal immune functions. However, under pathological and chronic inflammatory conditions, such as cancer, infectious diseases, autoimmune diseases or sepsis, normal myeloid differentiation is blocked, and the continuous stimulation of bone marrow production leads to the expansion of MDSC.

[0003] MDSCs exhibit a wide range of phenotypes and are involved in tumor progression. In mice, MDSCs are marked by CD11b and Gr1 and can be divided into two subpopulations: multinuclear MDSCs (PMN-MDSCs) marked by CD11b+Ly6GhiLy6C- / low, and mononuclear MDSCs (M-MDSCs) marked by CD11b+Ly6G- / lowLy6Chi. Human MDSCs are also defined by surface markers. Human M-MDSCs are defined as CD14+CD33+CD11b+HLA-DR-. Unlike M-MDSCs, PMN-MDSCs are CD15+CD33+CD11b+HLA-DR-. Both M-MDSCs and PMN-MDSCs can suppress T cells and NK cells by secreting reactive oxygen species (ROS), nitric oxide (NO), and arginase-1 (Arg-1). In some cases, they can also induce regulatory T cells (Tregs), thereby suppressing the host immune response, contributing to tumor immune evasion, and further promoting tumor initiation and progression.

[0004] MDSCs go through two stages to function: the first is their expansion and aggregation, and the second is their activation under the continued influence of tumor factors to form cells with immunosuppressive functions. MDSC expansion, aggregation, and activation are primarily regulated by a variety of chemokines and inflammatory factors secreted by tumor cells and tumor stromal cells, including but not limited to granulocyte / macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-6, IL-10, IL-12, cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and vascular endothelial growth factor (VEGF). When MDSCs accumulate and migrate to the periphery, their number and proportion increase tenfold, accounting for approximately 10% of peripheral blood mononuclear cells (PBMCs) throughout the disease process. Studies have reported that ascites-derived IL-6 and IL-10 can amplify CD14+HLA-DR- / low MDSCs in ovarian cancer patients; that Snail upregulates CXCR2 ligands to recruit MDSCs and promote ovarian cancer progression; and that during colorectal cancer metastasis, CXCL1 can recruit CXCR2+ MDSCs and promote the formation of premetastatic lesions. Furthermore, during anti-tumor therapy that blocks CSF1R, tumor-associated fibroblasts can recruit PMN-MDSCs, thereby weakening the therapeutic effect. However, further research is needed to understand the key tumor-associated cytokines that amplify, recruit, and activate MDSCs in ovarian cancer and their mechanisms of action.

[0005] Research progress on serum amyloid A in tumors

[0006] Serum amyloid A (SAA) is the major acute-phase protein in humans, primarily synthesized and secreted by the liver. Its levels increase 1000-fold in response to infection, trauma, cancer, or other inflammatory events. SAA consists of SAA1, SAA2, SAA3, and SAA4. SAA1 has three isoforms: SAA1α, SAA1β, and SAA1γ, while SAA2 also has two isoforms: SAA2α and SAA2β. Because serum concentrations of SAA1 and SAA2 increase 1000-fold during acute reactions, these two isoforms are referred to as "acute-phase SAA (A-SAA)." Once secreted into the circulation, A-SAA binds to high-density lipoprotein (HDL), displacing apolipoprotein (Apo)-AI. SAA3 is primarily expressed extrahepatically in other mammals and has been detected at very low concentrations in humans. In contrast to A-SAA, SAA4 is constitutively present in the circulation. For this reason, SAA4 is also referred to as "constitutive SAA" (C-SAA).

[0007] SAA proteins are encoded by a family of closely related genes and are remarkably conserved throughout vertebrate evolution. Despite their small size, SAA proteins have been carefully catalogued for their sequences and polymorphisms. SAA functions as cytokine-like proteins in cell-to-cell communication and feedback in inflammatory, immunological, oncological, and protective pathways. SAA has been evaluated as a potential serum biomarker for many tumors, including lung cancer, renal cancer, endometrial cancer, uterine papillary serous carcinoma, and melanoma. However, the specific role and mechanism of SAA1 in ovarian cancer have not yet been reported, and therefore, the relationship between SAA1 and ovarian cancer warrants further investigation.

[0008] 3. SAA1 as a potential therapeutic target

[0009] Although SAA1 has been reported to play a role in certain cancers, its specific function and potential as a therapeutic target in ovarian cancer have not been fully validated. Existing research has primarily focused on the relationship between its expression level and tumor prognosis, while little is known about its role in tumor-derived exosomes and its regulatory mechanisms on the immune microenvironment. Summary of the Invention

[0010] The purpose of the present invention is to address the deficiencies in the prior art and provide an application of SAA1 as a serum marker for predicting the prognosis of ovarian cancer and a potential therapeutic target.

[0011] In a first aspect, the present invention provides the use of SAA1 as a biomarker in preparing an ovarian cancer diagnostic kit.

[0012] In a second aspect, the present invention provides the use of SAA1 as a biomarker in preparing a kit for predicting the prognosis of ovarian cancer.

[0013] In a third aspect, the present invention provides use of a reagent for detecting SAA1 protein content in preparing an ovarian cancer diagnostic kit.

[0014] In a fourth aspect, the present invention provides use of a reagent for detecting SAA1 protein content in preparing a kit for predicting ovarian cancer prognosis.

[0015] In a fifth aspect, the present invention provides use of an inhibitor of SAA1 in the preparation of a drug for treating ovarian cancer.

[0016] The advantages of this invention are as follows: Through a series of experiments, the invention reveals a significant accumulation of myeloid-derived suppressor cells (MDSCs) in the peripheral blood and tumor tissues of ovarian cancer patients; SAA1 is elevated in patients with epithelial ovarian cancer (EOC) and associated with a poor prognosis; SAA1 promotes the proliferation of ovarian cancer cells in vitro; and SAA1 released by ovarian cancer cells recruits MDSCs through TLR2 / 4 receptors and promotes their differentiation. By deeply revealing the key role played by SAA1-MDSCs in the immunosuppression process of ovarian cancer, the invention innovatively proposes a new treatment strategy, which is undoubtedly of great scientific significance and also demonstrates great value in clinical application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Myeloid-derived suppressor cells (MDSCs) are prominently accumulated in the peripheral blood and tumor tissues of patients with ovarian cancer. (A) Flow cytometric analysis of M-MDSCs in the peripheral blood of patients with benign or malignant tumors. Statistical analysis of the percentage of M-MDSCs among monocytes. (B) Flow cytometric analysis of PMN-MDSCs in the peripheral blood of patients with benign or malignant tumors. Statistical analysis of the percentage of PMN-MDSCs among monocytes. (C) Flow cytometric analysis of the proportion of M-MDSCs in tumor tissues of patients with benign or malignant tumors. Statistical analysis of the percentage of M-MDSCs among monocytes. (D) Flow cytometric analysis of PMN-MDSCs in tumor tissues of patients with benign or malignant tumors. Statistical analysis of the percentage of PMN-MDSCs among monocytes. (E) Flow cytometric analysis of Treg cells in the peripheral blood of patients with benign or malignant tumors. Statistical analysis of the percentage of Treg cells among monocytes. (FH) qRT-PCR analysis of iNOS, IDO, and Arg-1 expression in tumor tissues from patients with benign or malignant tumors.

[0018] Figure 2SAA1 is elevated in patients with epithelial ovarian cancer (EOC) and associated with poor prognosis. (A) The most significantly differentially expressed genes after co-culture of SKOV3 cells with MDSCs in the GSE145374 dataset. (B) SAA1 expression in ovarian cancer tissues based on the GEPIA database. (C) The relationship between SAA1 expression and overall survival in ovarian cancer patients based on the GEPIA database. (DE) SAA1 expression in benign and malignant tumor tissues was detected by qRT-PCR, and its relationship with the clinical stage of EOC patients was analyzed. (F) SAA1 expression in the serum of patients with benign and malignant tumors was detected by ELISA. (GH) SAA1 expression in tumor tissues and adjacent tissues of EOC patients was detected by Western blotting. (I) The expression level and localization of SAA1 in tumor tissues were determined by IHC. (JL) Differential expression of SAA1 in normal ovarian epithelial cell lines and various ovarian cancer cell lines was detected by qRT-PCR and Western blotting.

[0019] Figure 3 SAA1 promotes ovarian cancer cell proliferation in vitro. (AB) The efficiency of SAA1 knockdown in A2780 cells was assessed by qRT-PCR and Western blotting. (CD) The efficiency of SAA1 overexpression in SKOV3 cells was assessed by qRT-PCR and Western blotting. (EF) SAA1 expression in cell supernatants was assessed by ELISA after SAA1 knockdown in A2780 cells and after SAA1 overexpression in SKOV3 cells. (GH) The effect of SAA1 knockdown or overexpression on ovarian cancer cell proliferation was assessed by CCK8 assay. (IL) The proliferation capacity of ovarian cancer cells after SAA1 knockdown or overexpression was demonstrated by EdU assay. (MP) The effect of SAA1 knockdown or overexpression on the clonogenic capacity of ovarian cancer cells was assessed by clonogenic assay.

[0020] Figure 4SAA1 released by ovarian cancer cells recruits MDSCs through TLR2 / 4 receptors and promotes their differentiation. (AB) Flow cytometry was used to examine the expression of TLR2 on the surface of MDSCs in the peripheral blood of patients with benign and malignant tumors. (CD) Flow cytometry was used to examine the expression of TLR4 on the surface of MDSCs in the peripheral blood of patients with benign and malignant tumors. (EF) Correlation analysis between SAA1 and TLR2 / 4 based on the TIMER database. (GH) Reaction experiments were conducted to examine the effects of adding recombinant SAA1 or the TLR2 / 4 inhibitor SsnB on the ability of A2780 cell supernatants to recruit MDSCs. (IJ) Reaction experiments were conducted to examine the effects of adding recombinant SAA1 or the TLR2 / 4 inhibitor SsnB on the ability of ID8 cell supernatants to recruit MDSCs. (KL) Reaction experiments were conducted to examine the effects of adding recombinant SAA1 or the TLR2 / 4 inhibitor SsnB on the ability of A2780 cell supernatants to induce differentiation of GMPs into MDSCs. DETAILED DESCRIPTION

[0021] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content of the present invention record, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the application's appended claims.

[0022] Example 1

[0023] 1. Experimental Materials

[0024] Data source:

[0025] The Cancer Genome Atlas (TCGA): used to analyze the relationship between SAA1 gene expression levels and pathological prognosis in ovarian cancer.

[0026] The Gene Expression Omnibus (GEO) database was used to further validate the expression of SAA1 in human ovarian cancer tissues.

[0027] Cancer Cell Line Encyclopedia (CCLE) project: used to compare the expression of SAA1 in epithelial ovarian cancer cell lines and normal immortalized cell lines.

[0028] Obstetrics and Gynecology Hospital of Tongji University: provided human ovarian cancer tissue and normal tissue samples for detection of SAA1 expression.

[0029] 2. Experimental methods

[0030] 1) Human peripheral blood and tumor tissue samples

[0031] From February 2022 to July 2023, blood and tissue samples were collected from patients with benign or malignant tumors at Shanghai First Maternity and Infant Health Care Hospital. None of the patients received radiotherapy or chemotherapy before surgery. Peripheral blood was collected before surgery, and peripheral blood mononuclear cells (PBMCs) were separated by density gradient centrifugation (Ficoll Paque Plus; GE Healthcare, Pittsburgh, PA, USA) and used directly in subsequent experiments. After surgery, the patient's tumor tissue was digested with trypsin and prepared into a single-cell suspension for further experiments. This study was approved by the Ethics Committee of Shanghai First Maternity and Infant Health Care Hospital, and all subjects signed an informed consent.

[0032] 2) Flow cytometry

[0033] After preparing the single cell suspension, incubate with the corresponding flow cytometry antibodies for 30 minutes for staining of surface molecular markers. If nuclear molecules need to be detected, first complete the surface antigen staining as described above, and then use Pharmingen TM Nuclear staining was performed using Transcription Factor Buffer Set (562574; BD Biosciences) according to the manufacturer's instructions. Intracellular cytokine staining required incubation with Cell Activation Cocktail (with Brefeldin A) (423303; Biolegend) at 37°C for 6 hours to induce factor release, followed by surface antigen staining and using Cytofix / Cytoperm TM Fixation / Permeabilization Kit (554714; BD Biosciences) was used to stain intracellular factors. The stained cells were detected by flow cytometry (BD, FACSCalibur) and analyzed using FlowJo V10.8.1 software. Human MDSCs were defined as CD11b + CD33 + HLA-DR-, where M-MDSCs are CD11b + CD33 + CD14 + , PMN-MDSCs are CD11b + CD33 + CD15 + ;CD4 + T cells are CD3 + CD4 + , CD8 + T cells are CD3 + CD8 + Regulatory T cells (Tregs) are CD4 +CD25 + FOXP3 + Mouse M-MDSCs are CD45 + CD11b + Ly6G- / low Ly6C^high, G-MDSCs are CD45 + CD11b + Ly6G^high Ly6C- / low; Tregs are CD45 + CD4 + CD25 + FOXP3 + , CD4 + T cells are CD45 + CD4 + , CD8 + T cells are CD45 + CD8 + At the same time, CD8 secretion of IFN-γ + T cells are CD45 + CD8 + IFN-γ + , CD45 secretes GZMB + CD8 + GZMB + .

[0034] 3) RNA extraction, reverse transcription, and real-time quantitative PCR (qRT-PCR)

[0035] Total RNA from cells and tissues was extracted using RNAiso Plus (Takara, Japan) according to the manufacturer's instructions. cDNA was then synthesized using ABScript IIIRT Master Mix for PCR reagent (ABclonal, China). Genious 2X SYBR Green Fast qPCR Mix (Low Rox Premixed) (ABclonal, China) was used in QuantStudio TM Amplification was performed using the Design & Analysis Software 1.3.1 platform. The amplification program was as follows: initial denaturation at 95°C for 3 minutes, followed by 40 cycles of denaturation at 95°C for 5 seconds. GAPDH was used as an internal reference, and relative expression was calculated using the 2-ΔΔCT method. All primers were synthesized by Tsingke Biotech (Shanghai, China).

[0036] 4) Western Blot

[0037] Cell and tissue proteins were extracted using RIPA lysis buffer (Beyotime, China) containing protease / phosphatase inhibitors and PMSF. Polyacrylamide gels (Epizyme, China) were prepared according to protein molecular weight and separated by 10% SDS-PAGE electrophoresis. After electrophoresis, proteins were transferred to PVDF membranes (Millipore, USA), blocked with 5% skim milk powder for 1 hour at room temperature, and then incubated with primary antibodies overnight at 4°C. The following day, secondary antibodies were added and incubated for 1 hour at room temperature. Enhanced chemiluminescence reagent (Millipore, USA) was used for visualization. β-Actin was used as an internal control.

[0038] 5) Enzyme-linked immunosorbent assay (ELISA)

[0039] Peripheral blood was collected from patients, centrifuged, and stored at −80°C. Cells were cultured in 24-well plates for 48 hours, then replaced with serum-free medium. Cultures were then continued for another 48 hours, and the supernatant was collected and frozen. SAA1 concentrations in serum and cell supernatants were determined using an SAA1 ELISA kit (ABclonal, China) according to the manufacturer's instructions.

[0040] 6) Immunohistochemistry (IHC)

[0041] Tissues from patients with benign or malignant tumors were collected, fixed in 4% paraformaldehyde, and then embedded in paraffin. Sections were deparaffinized in xylene, dehydrated with graded alcohols, and treated with 3% hydrogen peroxide to block endogenous peroxidases. Antigen retrieval was then performed. Tissue sections were then incubated with primary antibodies overnight at 4°C and with the corresponding secondary antibodies for 1 hour at room temperature. Finally, DAB was used for color development and counterstained with hematoxylin.

[0042] 7) Cell Culture

[0043] Human normal ovarian epithelial cell line (IOSE), ovarian cancer cell lines (A2780, SKOV3, ES-2, HEY), human embryonic kidney cell line (293T), and mouse ovarian cancer cell line (ID8) were purchased from the American Type Culture Collection (ATCC, USA). IOSE, A2780, SKOV3, and HEY cells were cultured in RPMI-1640 medium (VivaCell, China) supplemented with 10% fetal bovine serum (FBS, Gibco, USA); ES-2, 293T, and ID8 cells were cultured in DMEM medium (VivaCell, China) supplemented with 10% FBS. All cells were maintained in a 37°C, 5% CO2 incubator.

[0044] 8) Lentiviral Transfection to Construct Stable Strains

[0045] The shRNA vector pLKO.1-shSAA1-Puro for human SAA1 knockdown was designed and synthesized by Tsingke Biotech (Shanghai, China), and the mouse SAA1 knockdown vector PGMLV-shSAA1-Puro was designed and synthesized by Geneseed (Shanghai, China). The sgRNA for mouse SAA1 knockdown was designed by the Zhang Lab and synthesized by Tsingke, constructed into the lentiCRISPR V2-sgSAA1-Puro vector. Full-length human SAA1 cDNA was provided by You Bao Bio (Hunan, China) for overexpression experiments. These vectors, along with the packaging system, were transfected into 293T cells using PEI (Servicebio, China), and the viral supernatant was collected 48 hours later. When the target cells reached 60%–70% confluency, they were co-infected with the viral supernatant using Polybrene (Geneseed, China). After 48 hours, puromycin was added to select for uninfected cells, and the remaining cells were considered stably transfected.

[0046] 9) Cell proliferation assay (CCK-8 method)

[0047] CCK-8 (Cell Counting Kit-8) was used to detect cell proliferation. 1×10 3 The cells were cultured at 0, 24, 48, 72, and 96 hours, and the culture medium was discarded. 100 μl of serum-free culture medium containing 10% CCK-8 reagent (New Cell & Molecular Biotech, China) was added and incubated at 37°C for 2 hours. The absorbance was then read at a wavelength of 450 nm.

[0048] 10) EdU cell proliferation assay

[0049] When the cells reached 60%–70% confluency, EdU reagent was added to the culture system and incubated in an incubator for 2 hours. The cells were then fixed with 4% paraformaldehyde, stained with Hoechst 33342 for nuclear staining, and the proportion of EdU-positive cells was observed and counted using a fluorescence microscope. The kit was from the Cell-Light EdU DNA Cell Proliferation Kit (RiboBio, China).

[0050] 11) Colony Formation Assay

[0051] 1 × 10 3 Culture target cells for 1–2 weeks until distinct clonal colonies form. Discard the culture supernatant, fix with 4% paraformaldehyde for 15 minutes, stain with crystal violet for 15 minutes, and rinse. Photograph and count the colonies.

[0052] 12) Transwell migration / invasion assay

[0053] 8μm Transwell inserts (Corning, USA) were placed in a 24-well plate. 500μl of complete culture medium containing 20% ​​FBS was added to the lower chamber, and 200μl of a cell suspension in serum-free culture medium was added to the upper chamber. For invasion assays, the inner surface of the upper chamber membrane was pre-coated with Matrigel (BD Biosciences, USA). After incubation at 37°C for 24 hours, cells on the inner membrane of the insert were gently wiped off with a cotton swab. Cells on the outer membrane were retained, fixed with 4% paraformaldehyde, stained with crystal violet, and photographed and counted under a microscope. Images were analyzed using ImageJ software.

[0054] 13) MDSCs isolation

[0055] Peripheral blood was collected from ovarian cancer patients and spleen tissue from tumor-bearing mice. Ficoll-Paque Plus density gradient centrifugation was performed, and the white flocculent cells in the middle layer were aspirated. MDSCs were then isolated using the human CD33 MicroBeads Kit (130-045-501, Miltenyi Biotec) and the mouse CD115 MicroBeads Kit (130-096-354, Miltenyi Biotec), respectively.

[0056] 14) MDSCs migration assay

[0057] 8μm pore Transwell inserts (Corning, USA) were placed in 24-well plates. 500μl of 20% FBS-containing or different treatment group cell supernatant was added to the lower chamber, and 200μl of serum-free MDSCs resuspended in the upper chamber was added. For this experiment, 200ng / ml of recombinant SAA1 protein (HY-P70510 / human, HY-P700309 / mouse, MedChemExpress) and 20μM of the TLR2 / 4 inhibitor Sparstolonin B (SsnB, HY-116213, MedChemExpress) were used. After incubation at 37°C for 20–24 hours, cells were removed from the chambers and photographed and counted under a microscope.

[0058] 15) Induction of granulocyte-monocyte progenitor (GMP) differentiation experiment

[0059] Umbilical cord blood samples were collected from healthy donors, and the intermediate layer cells were extracted after Ficoll Paque Plus density gradient centrifugation. The obtained GMPs were induced and cultured with the supernatant of ovarian cancer cells from different treatment groups. The culture system was supplemented with IL-6 and GM-CSF (both 40ng / ml), and recombinant proteins SAA1 (200ng / ml) and SsnB (20μM) were added. After incubation for 48 hours, cells were collected and CD11b was analyzed by flow cytometry. + CD33 + HLA-DR- cell proportion.

[0060] 3. Experimental results

[0061] 1) Myeloid-derived suppressor cells (MDSCs) are significantly accumulated in the peripheral blood and tumor tissues of ovarian cancer patients Figure 1 .

[0062] 2) Expression profile chip screening of key differentially expressed genes in ovarian cancer cells after co-culture with MDSCs

[0063] Analysis of GSE145374 revealed that SAA1 was significantly increased in ovarian cancer cells SKOV3 after culture with MDSCs. The high expression of SAA1 was further confirmed in ovarian cancer samples and cell lines. Figure 2 .

[0064] 3) SAA1 promotes proliferation and colony formation of ovarian cancer cells in vitro

[0065] After identifying the key molecule SAA1, we knocked down SAA1 in the A2780 cell line and overexpressed SAA1 in the SKOV3 cell line. We then tested the effect of SAA1 on the proliferation of ovarian cancer cells using CCK8 / EDU assays and the effect of SAA1 on the clone formation of ovarian cancer cells using plate cloning assays. Figure 3 .

[0066] 4) Ovarian cancer cells secrete SAA1 that acts on TLR2 / 4 receptors on MDSCs, recruiting polarized MDSCs

[0067] After confirming the expression of TLR2 / 4 on MDSCs by flow cytometry, we further confirmed through experiments that ovarian cancer cells can secrete SAA1 to act on MDSCs expressing TLR2 / 4 receptors and recruit polarized MDSCs. Figure 4 .

[0068] Summarize:

[0069] Our research results clearly show that SAA1 is significantly overexpressed in ovarian cancer cells and tissues, and is closely and significantly associated with immune escape in ovarian cancer. A deeper analysis of the mechanism of action reveals that ovarian cancer cells can release SAA1, which acts on TLR2 / 4 on the surface of MDSCs to recruit and activate MDSCs.

[0070] Overall, although certain progress has been made in the field of tumor research on SAA1 and MDSCs, there are still many research gaps to be explored in terms of the specific mechanism of action of SAA1-MDSCs in ovarian cancer, especially their fine regulation mechanism of the tumor immune microenvironment, and the huge potential they hold as therapeutic targets.

[0071] Currently, existing ovarian cancer treatments are not effective enough in actual clinical applications, which greatly limits the treatment outcomes for patients. Therefore, finding new therapeutic targets and strategies to effectively improve the prognosis of ovarian cancer patients has become a top priority.

[0072] It is noteworthy that SAA1 has the potential to become a potential biomarker for predicting ovarian cancer prognosis. Based on this, this study deeply reveals the key role played by SAA1-MDSCs in the immunosuppressive process of ovarian cancer and innovatively proposes a new treatment strategy, which is undoubtedly of great scientific significance and also demonstrates great value in clinical application.

[0073] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. Application of SAA1 as a biomarker in the preparation of ovarian cancer diagnostic kits.

2. Application of SAA1 as a biomarker in the preparation of an ovarian cancer prognosis prediction kit.

3. Application of reagents for detecting SAA1 protein content in the preparation of ovarian cancer diagnostic kits.

4. Application of reagents for detecting SAA1 protein content in the preparation of ovarian cancer prognosis prediction kits.

5. Application of SAA1 inhibitors in the preparation of drugs for the treatment of ovarian cancer.

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