Down-regulation of poly (ADP-ribose) polymerase 1 leads to change of hydroquinone cytotoxicity in TK6 cells

AbstractHydroquinone (HQ), one of the most important metabolites derived from benzene, is known to be associated with acute myelogenous leukemia risk; however, its carcinogenic mechanism remains unclear. In a previous study, we found that low-level of benzene exposure down-regulated the expression of poly(ADP-ribose)polymerase 1 (PARP1). Here, we employed RNA interference to knock down PARP1 expression in TK6 cells and explored the potential role of PARP1 in HQ-induced cytotoxicity. The results showed that stable PARP1-knockdown cells were successfully constructed and more than 80% inhibition of PARP1 expression was confirmed. We found that HQ treatment of TK6 cells decreased cell viability, increased cell apoptosis, and caspase3/7 activity. Knockdown of PARP1 in HQ-treated TK6 cells prevented caspase3 activation, and increased apoptosis than that in the wild-type TK6 cells, with fully functional PARP1. The results also showed that down-regulation of PARP1 led to a decrease in cell proliferation and an en...