Effect of receptor tyrosine phosphatase D on the characteristics of breast cancer stem cells / 临床与实验病理学杂志

ABSTRACT

Purpose To investigate the effect of protein tyrosine phosphatase receptor type D (PTPRD) on the characteristics of breast cancer stem cells. Method PTPRD expression in breast cancer cell line MDA-MB231 was down-regulated by small interference RNAs (siRNAs). Self-renewal ability of breast cancer stem cells (BCSCs) was detected by mammosphere formation assay. The holocolony forming ability was detected by colony formation assay. The proportion of CD44+/CD24- BCSCs was detected by flow cytometry. The ability of tumorigenesis of breast cancer cells in mice was sdudied with mouse tumorigenesis test. Separation of CD44+/CD24- stem cell population and non-stem cell population was isolated by immunomagnetic beads. Expression of PTPRD in stem cell and non-stem cell population was detected by Western blot and immunofluorescent. Results Down-regulation of PTPRD promoted the expression of stem cell markers ALDH1 and OCT-4. The expression of PTPRD in breast cancer stem cells was lower than than in non-stem cells (P<0.05). After PTPRD was down-regulated, the number of mammosphere (147±3.51) was significantly higher than that of the control group (106±12.5) (P<0.05), the proportion of holoclone [(35.9±3.4) ％] was significantly higher than that of the control group [(11.2±5.3) ％] (P<0.05), the proportion of CD44+/CD24- cells[(2.88±1.2) ％]was significantly higher than that of the control group [(0.6±0.4) ％], the in vivo tumorigenicity was significantly enhanced in nude mice (P<0.05). Conclusion The expression of PTPRD is lower in BCSCs. PTPRD may inhibit the self-renewal ability of breast cancer stem cells.