Alteration of the Bcl-2/Bax status of head and neck cancer cell lines by chemotherapeutic agents.

The Bcl-2 family of genes includes some important regulators of apoptosis. Among these genes, Bcl-2 and Bax control cell death, thus contributing to both tumor growth and drug sensitivity. We determined the levels of protein and RNA expression of Bcl-2 family in 21 head and neck cancer cell lines. Then using four cell lines, which were KB (Bcl-2+/Bax+), KCC-L871 (Bcl-2+/Bax-), YCU-T891 (Bcl-2-/Bax+) and TC901 (Bcl-2-/Bax-), we investigated the impact of Bcl-2/Bax status on sensitivity to the following chemotherapeutic agents; paclitaxel, cisplatin, vincristine and 5-fluorouracil. Immunohistochemistry and RT-PCR showed that 71% of the cell lines were Bcl-2 positive, 62% were Bax positive, 38% were Bcl-XL positive and 62% were Bcl-XS positive. After treatment with all the chemotherapeutic agents, Bax expression changed from negative to positive in TC901 cells. In KB cells, Bcl-2 expression decreased only after treatment with paclitaxel. YCU-T891 cells were sensitive to all of the drugs. In conclusion, Bcl-2/Bax status was correlated with drug sensitivity and treatment with chemotherapeutic agents induced apoptosis in these cancer cells.