7b, a novel amonafide analog, inhibited proliferation and phorbol 12-myristate 13-acetate/phytohemagglutinin-induced...

7b, a novel amonafide analog, has shown high antitumor activity against Raji B-cell lymphoma. We report here that 7b also shows high cytotoxicity against various T lymphoma cells, with the highest IC(50) (concentration for 50% cytotoxicity) value in Jurkat cells. In a previous study, p53-mutant Raji cells were sensitive to 7b treatment. In the present study, the Jurkat T lymphoma cells were characterized as p53-null. Additional assays showed that 7b could induce G1/S phase arrest and mitochondrial apoptosis in Jurkat cells, suggesting 7b as a potential drug candidate for treatment of T-cell lymphoma. This action was not affected by p53 status. Further analysis of molecular mechanisms revealed that up-regulation of p21 and the Bak/Bcl-2 ratio and down-regulation of UHRF1 and c-Myc were attributed to p73 activation. In turn, up-regulation of p73 was initiated by DNA damage-induced reactive oxygen species (ROS) formation. Interestingly, at non-toxic drug concentrations, 7b could also inhibit phorbol 12-myristate 13-acetate/phytohemagglutinin (PMA/PHA)-induced inflammatory responses of Jurkat T cells owing to the suppression of nuclear factor-κB (NF-κB) DNA-binding. Indeed, electrophoretic mobility shift assay and NF-κB binding assay showed that NF-κB DNA-binding was inhibited by 7b, and correspondingly, proinflammatory cytokine production was also decreased. In conclusion, 7b exhibits both antiproliferative and anti-inflammatory activities in T lymphoma cells.