CDCA8 is a key mediator of estrogen-stimulated cell proliferation in breast cancer cells.

Endocrine therapy is effective in the early stage of breast cancer treatment, and most tumor cells will gain the ability to proliferate under residual amounts of estrogen, which will cause the recurrence of the disease. The role of cell division cycle associated 8 (CDCA8) in Estradiol (E2)-stimulated breast cancer cells growth is investigated in this research. CDCA8 showed higher mRNA expression in E2-stimulated MCF7 and T47D cells, and such an increase could also be observed in tumor samples. CDCA8 shRNA inhibited the survival and growth detected by cell number and colony formation, while promoted cell cycle G1 phase arrest determined with flow cytometry, which coordinated with a decrease in E2-induced molecules, namely Cyclin D1 (CCND1), B-Cell CLL/Lymphoma 2 (BCL2), and an increase in apoptosis-related molecules, such as cyclin-dependent kinase inhibitor 1a (P21) and cyclin-dependent kinase inhibitor 1b (P27). Kaplan-Meier plot analysis indicated that higher CDCA8 expression was positively associated with poor prognosis with a probability lower than 0.4 at the five-year interval (p = 0.035). All of these suggest that CDCA8 is a key mediator of estrogen-stimulated breast cancer cell growth and survival, which can be utilized as a novel target in breast cancer treatment.