Basic Study

Induction of apoptosis in tumor cells by microwave irradiation

To assess induction of apoptosis in tumor cells by microwave irradiation, we examined %TUNEL positive cells and %sub G0-G1 phase cells by FACS analysis using an APO-BRDU kit. Figure 1 shows the induction of apoptosis of non-small-cell lung cancer (NSCLC) cell lines: H322, H1299 and H460, and 1 normal human lung fibroblast cell line: WI-38 and Figure 2 shows the accumulation of sub G0-G1 of those cell lines. Apoptosis and accumulation of sub G0-G1 were dramatically increased in temperature dependent manner in H322, H1299, and H460 treated with microwave irradiation, respectively.  (P<0,01). On the other hand, apoptosis and sub G0-G1 phase were not induced in WI-38 after microwave irradiation. These results suggested that microwave treatment enhanced the inhibition of tumor growth associated with cell apoptosis remarkably induced, in particular, by moderate microwave treatment. Mean value of percent apoptosis treated by moderate micrave treatment was 86.0%, 74.2%, 83.9%, and 3.7% in H322, H1299, H460, and WI-38, respectively. Those results were NSCLC cell-specific, yet did not showed cytotoxicity for WI-38 (normal cells) temperature below 43°C. (Results from experiments conducted by Dr. Motomura Tadashi, Associate Professor, Baylor College of Medicine, United States).

 

Figure 1

 

 

Figure 2