Identification of Cancer Stem-like Side Population Cells in Ovarian Cancer Cell Line OVCAR-3

ABSTRACT

Side population (SP) cells may enrich stem-like cells in many normal and malignant tissues. However, SP method application has drawn special attention to the field of stem cell research, and the existence of SP cells in cell culture is being debated, most probably because different cell lines require different technical modifications, especially when cell staining is considered. In this study, the authors aimed to disclose whether the hoechst33342 staining required extensive optimization for identifying SP cells in the human ovarian cancer cell line OVCAR-3. After systematic evaluations, it was found that only 2.5μg/mL hoechst33342 staining of the cells for 60 min could get an ideal SP population, which accounted for 0.9% of the whole cell population. The sorted SP cells showed significantly higher colony formation efficiency than the non-side population (NSP) cells, and only the SP cells could form holoclones. Real-time PCR disclosed that SP cells expressed higher levels of “stemness” gene Oct3/4 than the NSP cells did, indicating that the SP cells might harbor cancer stem cells in this cell line. The results highlight the necessity of SP method optimization in cell studies, and the SP cells in this cell line merit further studies when cancer stem cell identification and isolation are considered.

Keywords:

• OVCAR-3
• Oct3/4
• cancer stem cell
• FACS
• side population
• RT-PCR
• immunocytochemistry

Declaration of Interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.