Exploring The Heterogeneity And Chemoresistance Mechanism Of Ovarian Cancer Based On Single-Cell Transcriptome Sequencing

BackgroundOvarian cancer is one of the common female reproductive system tumors in China,which is characterized as late detection,high probability of drug resistance and recurrence,and poor prognosis.The first-line treatment for high-grade serous ovarian cancer(HGSOC),the most common pathological subtype of ovarian cancer,is tumor debulking surgery combined with platinum-based chemotherapy.As ovarian cancer has large heterogeneity,which will lead to the progressive tumor proliferation,invasion ability and change of sensitivity to chemotherapeutic drugs,most patients will eventually relapse even die due to chemotherapy resistance.However,further investigation of the mechanism underlying platinum resistance and the heterogeneity of ovarian cancer cells is still required.In this study,a single-cell transcriptome profile of eight cases of HGSOC including primary,recurrent and metastatic loci,was constructed to explore the heterogeneity and chemo-resistance mechanism of ovarian cancer.Methods1.One platinum-sensitive relapsed ovarian cancer specimen was collected for single-cell transcriptome sequencing,and other seven ovarian cancer single-cell transcriptome datas were collected from the public database for integration analysis.The Seurat algorithm was used to build the single-cell transcriptome profile of eight ovarian cancer samples.Cell types of ovarian cancer were identified by specific marker genes.2.Tumor cells were extracted from eight ovarian cancer samples and were performed re-clustering analysis.Enrichment analysis was performed to analyse expression of tumor biological behavior pathways in tumor samples by ssGSEA algorithm.3.The high expression genes of tumor cells in drug resistance samples were screened.The prognostic analysis of target genes was performed based on TCGA database to figure out the gene that may be associated with chemotherapy resistance and poor prognosis.4.Malignant evolution trajectory of tumor cells from platinum-resistant samples Ml and M2 were performed by Monocle algorithm.The potential role of ANXA2 in the formation of platinum-resistant phenotypes were explored.Results1.Single-cell transcriptome profile of eight cases of ovarian cancer were constructed.The cell populations were divided into epithelial cells,endothelial cells,myeloid cells,B lymphocytes,T lymphocytes and cancer associated fibroblasts.2.Enrichment analysis of eight cases of ovarian cancer samples showed that there were total differences in biological function and tumor signaling pathway enrichment in different samples.3.ANXA2 was significantly overexpressed in chemotherapy-resistant ovarian cancer tumor cells comparing with that in chemotherapy-sensitive ovarian cancer.The high expression of ANXA2 was associated with poor prognosis of ovarian cancer patients.4.Malignant derivation trajectories of tumor cells in platinum-resistant specimens Ml and M2 were found,and the expression of ANXA2 was increased in the formation of platinum-resistant phenotype.ConclusionIn this study,a single-cell transcriptome profile of eight ovarian cancer samples was constructed.Tumor heterogeneity including different gene expression patterns,biological functions and tumor signaling pathways were identified.ANXA2 was highly expressed in chemotherapy-resistant specimens and increased at the endpoint of platinum-resistant tumor cell evolution trajectory.High expression of ANXA2 was associated with poor prognosis of ovarian cancer patients,suggesting that high expression of ANXA2 was involved in the development of drug-resistant ovarian cancer cells.