Structural injury of osteosarcoma mitochondria by a novel antitumour agent, 2-methylfuranonaphthoquinone

The effect of the novel anticancer 2-methylnaphtho[2,3-b]furan-4,9-dione (F NQ3) on human osteosarcoma cell lines (HuO9 and HuO9N2) was investigated. T he IC50 values of FNQ3 were 5.95 mu M for HuO9 and 3.86 mu M for HuO9N2, wh ile that for normal fibroblasts (WI-38 cell line) was 35.8 mu M. The select ivity in antitumour activity which was estimated from the IC50 ratio of nor mal fibroblasts to tumour cells was 6.0 and 9.3 fold for HuO9 and HuO9N2, r espectively FNQ3 at 23.6 mu M selectively injured mitochondria of HuO9 cell s starting at 36 h and HuO9N2 cells at 24 h, whereas WI-38 cells were unaff ected even after 72 h. These results demonstrated that FNQ3 was selectively toxic to the mitochondria of osteosarcoma cells similar to carcinoma cells (Pan et al. (1997) J. Electron Microsc. 46: 181), in comparison to normal cells.