Natural static magnetic field-induced apoptosis in liver cancer cell.

Purpose: To observe the apoptotic effects of NSMF on human hepatoma cells and to investigate the mechanisms. Materials and methods: Human hepatoma cell line Bel-7402 and Hep G-2 were treated by 0.2 T rotary NSMF (30 min/d) with 250 Hz, 400 Hz and 500 Hz for 3 d and 6 d, respectively. Apoptosis was analyzed with flow cytometry. Cell proliferation was measured with XTT assay. Expression of Bcl-2, caspase3/8/9 was analyzed with ELISA. Results: After 6 d treatment, significant apoptosis was induced by 400 Hz in Bel-7402 cells. Slight cell apoptosis was observed at 250 Hz, while Hep G-2 cells exhibited slight apoptosis at 250 Hz and 400 Hz. After 3 d treatment, no apoptosis exhibited in both cell types. Compared with control group, expression of Bcl-2 and Caspase 8 in treated Bel-7402 cells were significantly reduced (p<0.01), while Caspase 3 and Caspase 9 were significantly upregulated (p<0.01). Conclusions: NSMF upregulates caspase 9 and downregulates Bel-2 expression, which results in higher level of active caspase 3 to trigger apoptosis in cells. Different cell types require different NSMF factors like rotary frequency and treatment time to induce apoptosis.