Objective: To study the arsenic trioxide (As(2)O(3)) induced apoptosis in a human small cell lung cancer cell line (NeI-H cells) and its possible mechanisms.
Methods: Apoptotic cells were detected by the TUNEL method. The expression of p53 and bcl-2 was analyzed with immunohistochemical staining.
Results: NeI-H cells showed the sub-G(1) peak after treatment with As(2)O(3) (0.5 micromol/L, 1.0 micromol/L, and 2.0 micromol/L) for 72 hours. The ratio of apoptotic cells increased with the increasing concentrations of the drug and the time of culture. Immunohistochemical staining of NeI-H cells showed increased expression of p53, but decreased expression of bcl-2 with the increasing concentrations of the drug.
Conclusion: The anti-carcinogenic effect of As(2)O(3) is due to the induction of cell apoptosis. Up-regulation of the p53 gene and down-regulation of the bcl-2 gene may be an underlining mechanism.