HPV E6 Knockdown Restores Adenovirus Mediated-Estrogen Response Element Linked p53 Gene Transfer in HeLa Cells

p53 is inactivated and degraded by the E6 protein encoded by the integrated human papillomavirus (HPV) in the cervical cancers (Scheffner et al., 1990). The susceptibility of p53 to degradation by the E6 protein varies between the arginine and proline variants at codon 72 of p53 (Storey et al., 1998). In vivo studies demonstrate that the arginine p53 variant is seven times more susceptible to degradation by the E6 protein, compared with the proline variant (Storey et al., 1998). However, the results of clinical studies are controversial, with the majority of studies demonstrating no significant difference between individuals harboring the arginine or proline p53 variant (Andersson et al., 2001; Klug et al., 2009; Nunobiki et al., 2011; Habbous et al., 2012). We considered that hormonal factors may affect these results. The estrogen response element (ERE) is a DNA sequence (-GGTCAnnnTGACC-) that when bound by the estrogen receptor, leads to the transcriptional activation of target genes (Klinge et al., 2001). We found that the ERE