M₂-A induces apoptosis and G₂-M arrest via inhibiting PI3 K/Akt pathway in HL60 cells

Amonafide, a naphthalimide derivative, although selected for exploratory clinical trials for its potent anticancer activity, has long been challenged by its unpredictable side effects. In the present study, a novel amonafide analogue, M₂-A 2-(2-(dimethylamino)ethyl)-6-(thiophene-2-ylmethylamino)-1H-benzo[de]isoquinoline-1,3(2H)-dione was ascribed to its potent effects on topoisomerase IIα. Moreover, our investigation indicates that M₂-A induces G₂/M phase growth arrest through inhibiting PI3 K/Akt pathway. M₂-A inhibits proliferation of HeLa, HL60, HCT-8, A375, MCF-7 and MRC-5 cells, especially inhibits proliferation of HL60 with an IC₅₀ value of 18.86 μM. M₂-A can not only induce DNA fragmentation, but also enhance Annexin V-FITC binding of the cells. On the one hand the expression levels of protein Cyclin B1, Cdk1 changed in response to M₂-A treatment in HL60 cells. On the other hand we observed the inhibition of NF-κB nuclear translocation, up-regulation of Bax and down-regulation of Bcl-2, the caspase -3, -9 activity increase in HL60 cells after treated with M₂-A, which indicated that the mitochondrial pathway was involved in the apoptosis signal pathway. Our results showed that the phosphorylation of p85/PI3 K and Akt decreased following M₂-A treatment. In summary, M₂-A displayed a significant anti-tumor effect through cell cycle arrest and apoptotic induction in HL60 cells, which suggested that M₂-A might have therapeutic potential against leukaemia.