Apoptosis-inducing effect of spiroaminopyrimidine analogue in NB4 leukemia cells via down-regulation of BIRC5 expression

It has been reported that spiroaminopyrimidine derivatives inhibited the growth and proliferation of various cancer cell lines. In the present study, we evaluated cytotoxic and apoptosis-inducing effects of 2,4-diamino-1,3-diazaspiro[5.5]-9-tert-butyl-2, 4-diene-5-carbonitril (9-tBAP) on NB4 acute promyelocytic leukemia (APL) cells. The cells were treated with 10-100 µM of 9-tBAP. Cytotoxic activity of the compound was measured using the MTT assay. Apoptosis was investigated by Hoechst 33258 staining as well as by Annexin V/PI double staining. The compound under study was found to be highly active cell growth inhibitor with IC of 30.0 ± 3.5 µM inducing apoptosis in NB4 cells. Cell cycle analysis by flow cytometry showed a time-dependent increase in sub-G cell population. Real-time polymerase chain reaction analysis revealed that the treatment with the compound down-regulated the BIRC5 expression in a time-dependent manner. 9-tBAP displayed potent anti-leukemic activity in vitro thus warranting further investigation.