HPV16 E6-induced and E6AP-dependent inhibition of the transcriptional coactivator hADA3 in human cervical carcinoma cells.

To determine whether there exists an additional pathway of E6 that is independent of direct P53 degradation and whether hADA3, a transcriptional coactivator, is involved in this process. We investigated the association between E6 and hADA3, as well as E6-associated protein (E6AP) and hADA3, in SiHa cells via RNA interference technique. Our results showed that the expression of hADA3 protein was significantly increased, cellular proliferation was decreased and apoptotic rate was increased in SiHa cells treated by E6 siRNA and E6AP siRNA respectively. Our results suggested that oncoprotein E6 inhibits hADA3 in cervical cancer cells and this process is E6AP-dependent.