Effect Of Chemotherapy On The Enrichment Of CSC-like Cells And The Expression Of Related Stemness Genes In Ovarian Cancer

Background The theory of cancer stem cells (CSCs) states that a subset of cancer cells within a tumor has the ability to self-renew, differentiate and proliferate extensively. Besides the traditional methods to enrich CSCs by SP analysis, surface phenotype and serum-free culture, it has been proved that breast cancer cells with these properties of CSC could be enriched by sequential in vivo passage in chemotreated immunodeficiency mice.Objectives To investigate the effect of chemotherapy on the expression of sternness genes and surface markers,and the proportion of CSC-like cells in ovarian cancer cell xenografts model. To prove the chemotheraputic effect on those moleculars in ovarian carcinomas.Methods2human ovarian cancer cell lines were transplanted into the immunodeficiency mice to construct the xenografts model. The proportion of SP cells and colony-forming efficiency were evaluated between the chemo-and non-chemo-treated xenografts. Expressions of sternness genes and surface markers were also screened by immunohistochemistry and flow cytometry.The most up-regulated stemness gene was further detected by RT-PCR. Expressions of sternness genes were also analyzed by immunohistochemistry in47ovarian carcinomas before and after chemotherapy.Results Although the two groups of xenografts possessed the same surface phenotype with the cell lines, the SP cell proportion and proliferativecapacity was higher in chemo-treated group. Up-regulation of Bmi-1gene was ascertained by immunohistochemistry in ovarian carcinomas after chemotherapy and by RT-PCR in the chemo-treated xenografts,Conclusion CSC-like cells can be enriched by chemo-therapy, along with up-regulated sternness genes involving in the self-renewal mechanisms of CSC.