UCN-01 (7-hydroxystaurosporine) induces apoptosis and G1 arrest of both primary and metastatic oral cancer cell lines in vitro

Objective: Our aim was to clarify the in vitro antiproliferative effects of UCN-01 on human oral squamous cell carcinoma (OSCC) cell lines. Study design: Cell growth was measured by MTT assay, and cell cycling was assessed by flow cytometry. Changes in the levels of protein and protein phosphorylation were analyzed by Western blotting. In addition, tumor cell apoptosis was assessed by propidium iodide (PI) and annexin double-staining. Results: UCN-01 significantly inhibited the proliferation of all the OSCC cell lines, with a 50% inhibition concentration of about 300 nmol/L, and induced G1 arrest in these cell lines in a dose-dependent manner. Primary and metastatic oral cancer cell lines had different sensitivities to UCN-01. Our results showed that HSC-3 cells (primary-type OSCC) are less sensitive than LMF4 cells (metastatic-type OSCC) to UCN-01. In addition, the induction of p21 in OSCCs was found to be important for the suppression of tumor growth. Conclusion: The results of this study suggest that UCN-01 induces apoptosis and G1 arrest in OSCCs, albeit with different sensitivity of the primary and metastatic cell lines to UCN-01.