Apoptosis of murine melanoma cells induced by heavy-ion radiation combined with Tp53 gene transfer

Abstract

Purpose: To investigate the effect of exogenous wild type p53 (Tp53) on murine melanoma B16 cell apoptosis induced by carbon-ion beam (C-beam) irradiation.

Materials and methods: The murine cell line B16, which has wild-type Tp53 gene status was studied, as well as B16 cells transfected with an adenoviral vector containing the wild-type Tp53 gene (B16/Tp53). Cells were irradiated with C-beam and assayed for cell survival (colony-forming assay), cellular morphology (acridine orange assay), the frequency of apoptotic cells (fluorescence microscopy) and protein expression (Western blot analysis).

Results: The radiosensitivity of B16/Tp53 cells was significantly higher than that of B16 cells. In contrast with Tp53 transfer alone, the combination of C-beam with Tp53 transfer induced a higher proportion of apoptotic cells and micronuclei. After C-beam irradiation, there was no significant increased expression of the cyclin-dependent kinase inhibitor p21 and Tp53 in B16/Tp53 cells compared to B16 cells, but a decreased expression of murine double minute-2 (Mdm2) was observed.

Conclusion: The results of this study suggest the potential application of C-beam combined with Tp53 in the treatment of melanoma in human patients.

Keywords:

• Tp53
• carbon-ion beam
• apoptosis
• melanoma