Establishment and Characterization of Primary Human Ovarian Cancer Stem Cell Line (CD44+ve)

Abstract

 Ovarian cancer is ranked as the 7^th most lethal cancer worldwide with 239,000 new cases annually. The mortality rate is high because most ovarian tumors are diagnosed at advanced stages and are resistant to chemotherapy and thus incurable due to the lack of effective early detection of ovarian tumors. There is a small sub-population of ovarian tumor cells capable of self-renewal and differentiation into different cancer cell types, called cancer stem cells (CSCs), which might be responsible for cancer relapse. The CD44⁺ phenotype in ovarian tumor cells elucidates cancer initiating cell-like properties of promoting differentiation, metastasis, and chemotherapy-resistance. Increased expression of genes previously associated with CSCs promotes regenerative capacity by promoting stem cell function that can drive cancer relapse and metastasis. In this study we present a method to isolate the primary epithelial ovarian cancer cells from human solid tumor and establish CD44^+ve primary ovarian cancer stem cell (OCSC^CD44+ve) line using magnetic microbeads. Also we evaluated the expression of stemness genes Nanog, Sox2, Oct4, and Nestin by real-time qPCR analysis. Thequantitative analysis by real-time qPCRshows that OCSC^CD44+ve overexpressed the embryonic stem cell marker genes Nanog, Oct4, Sox2, and Nestin when compared with ovarian cancer cells OCC^CD44-ve as positive control and ovarian cells as negative control. We demonstrate that CD44 in malignant ovarian tumors is a critical molecule that exhibits cancer stem cell properties that enhance tumorigenicity and cancer metastasis. Our results provide a better understanding of ovarian CSCs, which is important for future in vivo studies with subsequent target therapy for preclinical studies.