| Background:Because of occult onset and high mortality rate,ovarian cancer threatens the females life seriously.Extensive transfer and chemotherapy resistance is the leading cause of ovarian cancer recurrence and death.In-depth study on the pathogenesis of ovarian cancer and exploration of effective intervention strategies are the keys to improve the survival rate of ovarian cancer.Small molecule peptides,especially endogenous peptides,have the characteristics of small molecular weight,strong targeting and low toxicity,and have a broad application prospect in the field of anti-tumor drug research.Objective:Analyze the differentially expressed peptides of high-grade serous ovarian cancer tissues and normal ovarian epithelial tissues,and preliminary explore the mechanism of peptides’ function.Methods:Take 3 high-grade serous ovarian cancer tissue samples as the experimental group and 3 normal ovarian epithelial tissue samples as the control group.Quantitative liquid chromatography tandem mass spectrometry(LC/MS)was used to detect endogenous peptides between the two groups.According to the high expression abundance and large differences between groups,two peptides that were most reduced in high-grade serous ovarian cancer tissues were selected(peptide 1derived from PAPD7,abbreviated as P1DP;peptides derived from S38AA;peptide 1derived from S38 AA abbreviated as P1DS)to verify its function through the CCK8 experiment,the Transwell invasion and migration experiments.The IC50 value was calculated by the CCK8 cytotoxicity test to explore the effect of P1 DS on the sensitivity of OVCAR3 cells to paclitaxel and cisplatin and the effect of P1 DS on the sensitivity of OVCAR3 cells to paclitaxel and cisplatin in the presence of tumor-associated macrophage(TAM).Use pull down combined with mass spectrometry to find proteins that may directly bind to P1 DS.High-throughput sequencing technology is used to find possible targets of P1 DS.Results:A total of 3992 peptides from 1805 precursor proteins were detected,of which 3,920 ± 36 peptides were detected in serous ovarian cancer tissue samples,and3,805 ± 76 peptides were detected in normal ovarian epithelial tissue samples.The results of cell function experiments show that P1 DS can significantly inhibited the invasion and migration of ovarian cancer cells,while P1 DP had no effect on the proliferation,invasion and migration of ovarian cancer cells.P1 DS does not affect the sensitivity of OVCAR3 cells to paclitaxel and cisplatin,but P1 DS can significantly reverse the promotion effect of TAM on drug resistance of OVCAR3 cells.Mass spectrometry analysis showed that 39 proteins were specifically detected in the biotin-P1 DS pull down eluate,proteins include CAH2,RAP1 A,IGHG1,EF1A1,KLHL7,PROF1,etc.are related to tumor migration.The results of high-throughput sequencing showed that after adding P1 DS,the expression levels of 15 genes were significantly reduced,and the expression levels of 18 genes were significantly increased(q <0.01,fold difference ≥ 2),further real-time quantitative polymerase chain reaction(q RT-PCR)verification found that the down-regulated SULT1A3 gene has the most significant changes.It is speculated that it may be an important target for P1 DS.Conclusion:This study analyzed the peptidome profiling of ovarian cancer,and selected two peptides for preliminary functional studies.It was found that the peptide P1 DS inhibited the invasion and migration of ovarian cancer cells.P1 DS can reverse TAM-mediated OVCAR3 cells resistance.According to the results of pull down combined with mass spectrometry analysis,it is presumed that P1 DS may play a role by binding certain proteins related to tumor migration.Combined with high-throughput sequencing and RT-q PCR results,it is preliminarily speculated that P1 DS may inhibit the invasion and migration of ovarian cancer by targeting SULT1A3. |
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