SOC1 inhibits HPV-E7-mediated transformation by inducing degradation of E7 protein

Masaki Kamio, Takafumi Yoshida, Hisanobu Ogata, Tsutomu Douchi, Yukihiro Nagata, Makoto Inoue, Mamoru Hasegawa, Yoshikazu Yonemitsu, Akihiko Yoshimura

Research output: Contribution to journalArticlepeer-review

55 Citations (Scopus)

Abstract

Human papilloma viruses (HPVs) are small double-stranded DNA viruses that infect mucosal and cutaneous epithelium and induce cervical cancer. It has been shown that interferon (IFN)γ suppresses proliferation of HPV-infected cells by suppressing expression of HPV E7. Here, we found that IFNγ induces not only suppression of E7 transcription but also proteasome-dependent degradation. Suppressor of cytokine signaling-1 (SOCS1)/JAB, a suppressor of cytokine signaling, is known to be induced by IFNγ, and functions as an antioncogene against various hematopoietic oncogenic proteins. SOCS1 contains the SOCS-box, which is shown to recruit ubiquitin transferase to the molecules that interact with SOCS1. We found that SOCS1 interacted with HPV E7 protein and induced ubiquitination and degradation of E7 in a SOCS-box-dependent manner. SOCS1 overexpression also increased Rb protein levels and suppressed proliferation of cervical cancer cell lines infected with HPV. Moreover, E7 protein levels were higher and Rb protein levels were lower in SOCS1-deficient fibroblasts infected with retrovirus vector carrying E7 gene than in wild-type fibroblasts. E7 induced anchorage-independent growth in SOCS1-deficient fibroblasts, but not in wild-type cells. These data suggested that SOCS1 plays an important role in regulating the levels of E7 protein and their transforming potential, and could be a new therapeutic tool for HPV-mediated tumors.

Original languageEnglish
Pages (from-to)3107-3115
Number of pages9
JournalOncogene
Volume23
Issue number17
DOIs
Publication statusPublished - 2004 Apr 15

Keywords

  • Cytokine
  • E7
  • Interferon gamma
  • Papilloma viruses
  • Proteasome
  • SOCS

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research

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