Kinesin Family Member 11 Enhances the Self-Renewal Ability of Breast Cancer Cells by Participating in the Wnt/β-Catenin Pathway

Purpose: Our previous studies have shown that kinesin family member 11 (KIF11) is markedly overexpressed in human breast cancer cells or tissues and positively correlated with distant metastasis and prognosis in patients with breast cancer, suggesting an important role in the regulation of cancer stem cells. Herein, we examined the role of KIF11 in breast cancer stem cells. Methods: In the current study, we validated our previous findings through analysis of data collected in The Cancer Genome Atlas. Endogenous KIF11 was stably silenced in MCF-7 and SKBR-3 cells. Flow cytometry was used to measure the proportion of side-population (SP) cells. Mammosphere culture and tumor implantation experiments in immunodeficient mice were used to assess the self-renewal ability of breast cancer cells. Real-time polymerase chain reaction, western blot, immunofluorescence staining, luciferase reporter assays and Wnt agonist treatment were conducted to investigate the signaling pathways regulated by KIF11. Results: We found that the expression level of KIF11 was positively correlated with stem cell-enrichment genes. The proportion of SP cells was significantly reduced in KIF11-silenced cells. Silencing endogenous KIF11 not only reduced the size and number of mammospheres in vitro, but also reduced the ability of breast cancer cells to form tumors in mice. Simultaneously, we found that KIF11 was involved in regulating the activation of the Wnt/beta-catenin signaling pathway. Conclusion: Endogenous KIF11 enhances the self-renewal of breast cancer cells by activating the Wnt/beta-catenin signaling pathway, thereby enhancing the characteristics of breast cancer stem cells.