HPV-mediated nuclear export of HP1? drives cervical tumorigenesis by downregulation of p53.

ABSTRACT: E6 oncoprotein derived from high-risk human papillomavirus (HPV) drives the development of cervical cancer through p53 degradation. Because cervical cancer therapies to inactivate HPV or E6 protein are not available, alternative strategies are required. Here, we show that HPV-mediated nuclear export of human heterochromatin protein 1? (HP1?) reduces the stability of p53 through UBE2L3-mediated p53 polyubiquitination during cervical cancer progression. In general, HP1 plays a key role in heterochromatin formation and transcription in the nucleus. However, our immunostaining data showed that the majority of HP1? is localized in the cytoplasm in HPV-mediated cervical cancer. We found that HPV E6 protein drives unusual nuclear export of HP1? through the interaction between the NES sequence of HP1? and exportin-1. The mutation of the NES sequence in HP1? led to nuclear retention of HP1? and reduced cervical cancer cell growth and tumor generation. We further discovered that HP1? directly suppresses the expression of UBE2L3 which drives E6-mediated proteasomal degradation of p53 in cervical cancer. Downregulation of UBE2L3 by overexpression of HP1? suppressed UBE2L3-dependent p53 degradation-promoting apoptosis of cervical cancer cells. Our findings propose a useful strategy to overcome p53 degradation in cervical cancer through the blockage of nuclear export of HP1?.

SUBMITTER: Yi SA 

PROVIDER: S-EPMC7429875 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature