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 Bar control cell death, thus contributing to b oth 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. T hen using four cell lines, which were KB (Bcl-2+/Bax+), KCC-L871 (Bcl-2+/Ba x-), YCU-T891 (Bcl-2-/Bax+) and TC901 (Bcl-2-/Bax-), we investigated the im pact of Bcl-2/Bax status on sensitivity to the following chemotherapeutic a gents; paclitaxel, cisplatin, vincristine and 5-fluorouracil. Immunohistoch emistry and RT-PCR showed that 71% of the cell lines were Bcl-2 positive, 6 2% were Bar positive, 38% were Bcl-X-L positive and 62% were Bcl-X-S positi ve. After treatment with all the chemotherapeutic agents, Bax expression ch anged from negative to positive in TC901 cells. In KB cells, Bcl-2 expressi on decreased only after treatment with paclitaxel. YCU-T891 cells were sens itive to all of the drugs. In conclusion, Bcl-2/Bax status was con elated w ith drug sensitivity and treatment with chemotherapeutic agents induced apo ptosis in these cancel cells.