Effect of intracellular localization of cyclin D1 on the proliferation in oral squamous cell carcinoma

Abstract

Cyclin D1 governs phosphorylation of the retinoblastoma protein (RB) and controls the G1 phase of cell cycles. This gene may well be necessary for cancer development. We investigated the expression and localization of cyclin D1 protein in HSC 4, an oral squamous cell carcinoma cell line. The results showed that cyclin D1 protein is located in the nuclei of proliferating cells in HSC 4. Furthermore, cyclin D1 protein is decreased and translocated from the nucleium to the cytoplasm under dense culture conditions. In anchorage-independent growth, HSC 4 stopped proliferation and cyclin D1 protein was localized in the cytoplasm. These findings suggest that cyclin D1 protein is related to the proliferation of cells and regulation of the cell cycle in oral squamous cell carcinoma.