Aim: To elucidate inhibition of protein kinase C α (PKC α) activity by staurosporine on apoptosis of oral cancer cell line tongue squamous cell carcinoma (TSCCa) cells and to clarify the role of survivin and caspase-3 in mediating apoptosis. Methods: TSCCa cell viability was measured by MTT assay after 100 nmol/L staurosporine treatment. Apoptotic cells were identified by using phase contrast microscopy, acridine orange/ethidium bromide staining, and flow cytometry. Level of PKC α and its subcellular location were investigated using Western blot analysis. Expression of survivin and caspase-3 were evaluated using immunocytochemistry. Results: Staurosporine significantly inhibited the cell viability of TSCCa cells in a dose- and time-dependent manner. Marked cell accumulation in G_2/M phase was observed after 100 nmol/L staurosporine exposure for 6 h and 12 h. In addition, the percentage of apoptosis increased in a time-dependent manner, from 2.9% in control cultures to approximately 27.4% at 100 nmol/L staurosporine treatment for 24 h. Staurosporine displayed difference in inhibitory efficacy between cytosolic and membrance-derived PKC α. The content of PKCα in membrane versus cyto-sol decreased quickly, from 0.45 in ethanol-treated control cultures to 0.18 after staurosporine exposure for 24 h (P<0.01). After treatment with staurosporine, a time-dependent reduction of survivin and an activation of caspase-3 were observed in TSCCa cells. Conclusion: Staurosporine inhibited cell viability and promoted apoptosis in TSCCa cells. Inhibition of PKCα activity might be a potential mechanism for staurosporine to induce apoptosis in this cell line. The cleavage of survivin and activation of caspase-3 signaling pathway might contribute to PKC α inhibition-induced apoptosis. Aim: To elucidate inhibition of protein kinase C α (PKC α) activity by staurosporine on apoptosis of oral cancer cell line tongue squamous cell carcinoma (TSCCa) cells and to clarify the role of survivin and caspase-3 in mediating apoptosis. Methods: TSCCa cell viability was measured by MTT assay after 100 nmol / L staurosporine treatment. Apoptotic cells were identified by using phase contrast microscopy, acridine orange / ethidium bromide staining, and flow cytometry. Level of PKC α and its subcellular location were investigated using Western blot analysis . Expression of survivin and caspase-3 were evaluated using immunocytochemistry. Results: Staurosporine significantly inhibited the cell viability of TSCCa cells in a dose- and time-dependent manner. Marked cell accumulation in G_2 / M phase was observed after 100 nmol / L staurosporine exposure for 6 h and 12 h. In addition, the percentage of apoptosis increased in a time-dependent manner, from 2.9% in control cultures to approximately 27.4% at 100 nmol / L staurosporine treatment for 24 h. Staurosporine displayed difference in inhibitory efficacy between cytosolic and membrance-derived PKC α. The content of PKCα in membrane versus cyto-sol decreased quickly, from 0.45 in ethanol-treated control cultures to 0.18 after staurosporine exposure for 24 h (P <0.01). After treatment with staurosporine, a time-dependent reduction of survivin and an activation of caspase-3 were observed in TSCCa cells. Conclusion: Staurosporine inhibited cell viability and promoted apoptosis in TSCCa cells . Inhibition of PKCα activity might be a potential mechanism for staurosporine to induce apoptosis in this cell line. The cleavage of survivin and activation of caspase-3 signaling pathway might contribute to PKC α inhibition-induced apoptosis.