The ubiquitin ligase CHIP acts as an upstream regulator of oncogenic pathways

Masashi Kajiro, Ryuichi Hirota, Yuka Nakajima, Kaori Kawanowa, Kae So-Ma, Ichiaki Ito, Yuri Yamaguchi, Sho Hei Ohie, Yasuhito Kobayashi, Yuko Seino, Miwako Kawano, Yoh Ichi Kawabe, Hiroyuki Takei, Shin Ichi Hayashi, Masafumi Kurosumi, Akiko Murayama, Keiji Kimura, Junn Yanagisawa

研究成果: Article査読

131 被引用数 (Scopus)


CHIP is a U-box-type ubiquitin ligase that induces ubiquitylation and degradation of its substrates, which include several oncogenic proteins. The relationship between CHIP and tumour progression, however, has not been elucidated. Here, we show that CHIP suppresses tumour progression in human breast cancer by inhibiting oncogenic pathways. CHIP levels were negatively correlated with the malignancy of human breast tumour tissues. In a nude mouse xenograft model, tumour growth and metastasis were significantly inhibited by CHIP expression. In contrast, knockdown of CHIP (shCHIP) in breast cancer cells resulted in rapid tumour growth and metastastic phenotypes in mice. In cell-based experiments, anchorage-independent growth and invasiveness of shCHIP cells was significantly elevated due to increased expression of Bcl2, Akt1, Smad and Twist. Proteomic analysis identified the transcriptional co-activator SRC-3 (refs 13, 14, 15, 16, 17, 18, 19) as a direct target for ubiquitylation and degradation by CHIP. Knocking down SRC-3 in shCHIP cells reduced the expression of Smad and Twist, and suppressed tumour metastasis in vivo. Conversely, SRC-3 co-expression prevented CHIP-induced suppression of metastasis formation. These observations demonstrate that CHIP inhibits anchorage-independent cell growth and metastatic potential by degrading oncogenic proteins including SRC-3.

ジャーナルNature cell biology
出版ステータスPublished - 2009

ASJC Scopus subject areas

  • 細胞生物学


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