Synthesis and Antitumor Activity of a New 7-Azaindole Derivative

We designed and synthesized a 7-azaindole derivative(TH1082), which was characterized by ¹H NMR and ¹³C-NMR. We investigated its antitumor effects on human melanoma A375 cells, human liver cancer SMMC cells and human breast cancer MCF-7 cells in vitro via 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay and also explored the mechanism of antiproliferation of them. The results show that TH1082 significantly inhibited the proliferation of these cells to different extent. The IC₅₀ values for A375 cells, SMMC cells and MCF-7 cells were 25.38, 48.70 and 76.94 μg/mL at 24 h, respectively. To observe cell morphological changes, acridine orange/ethidium bromide(AO/EB) staining and Hoechest33342/PI staining were carried out. These results indicate that TH1082 could induced the apoptosis of A375 cells. The apoptotic rates were (9.5±2.09)%, (18.9±2.25)% and (39.5±2.02)%(5, 10 and 20 μg/mL) for A375, SMMC and MCF-7 cell lines, respectively. Further, we determined the activities of caspase-3 and caspase-9 in A375 cells treated with TH1082 at different concentrations(0, 5, 10 and 20 μg/mL) or Z-VAD-FMK(20 μmol/L), a pan-caspase inhibitor for 24 h. The results show that TH1082 activated caspase-3 and caspase-9, and the activation could be blocked by Z-VAD-FMK. Taken together, these findings indicate that TH1082 could inhibit the proliferation of A375 cells via activating caspase-3 and caspase-9.