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Originally published In Press as doi:10.1074/jbc.M707307200 on December 6, 2007
J. Biol. Chem., Vol. 283, Issue 5, 2508-2517, February 1, 2008
PINCH-1 Regulates the ERK-Bim Pathway and Contributes to Apoptosis Resistance in Cancer Cells*
Ka Chen ,
Yizeng Tu ,
Yongjun Zhang ,
Harry C. Blair ,
Lin Zhang ¶, and
Chuanyue Wu ¶1
From the
Departments of Pathology and Pharmacology and the ¶University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
Resistance to apoptosis is a hallmark of cancer cells. We report here that PINCH-1, a cytoplasmic component of cell-extracellular matrix adhesions, is required for protection of multiple types of cancer cells from apoptosis. Furthermore, using HT-1080 fibrosarcoma cells as a model system, we have investigated the signaling pathway through which PINCH-1 contributes to apoptosis resistance. Loss of PINCH-1 markedly increases the level of Bim and promotes Bim translocation to mitochondria, resulting in activation of the intrinsic apoptosis pathway. Depletion of Bim completely blocked apoptosis induced by the loss of PINCH-1. Thus, PINCH-1 contributes to apoptosis resistance through suppression of Bim. Mechanistically, PINCH-1 suppresses Bim not only transcriptionally but also post-transcriptionally. PINCH-1 promotes activating phosphorylation of Src family kinase and ERK1/2. Consistent with this, ERK1/2-mediated Ser69 phosphorylation of Bim, a key signal for turnover of Bim, is suppressed by the removal of PINCH-1. Our results demonstrate a strong dependence of multiple types of apoptosis-resistant cancer cells on PINCH-1 and provide new insights into the molecular mechanism by which cancer cells are protected from apoptosis.
Received for publication, August 30, 2007
, and in revised form, November 12, 2007.
* This work was supported by National Institutes of Health Grants GM65188 and DK54639 (to C. W.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. S1–S3.
1 To whom correspondence should be addressed: Dept. of Pathology, University of Pittsburgh, 707B Scaife Hall, 3550 Terrace St., Pittsburgh, PA 15261. Tel.: 412-648-2350; Fax: 509-561-4062; E-mail: carywu{at}pitt.edu.

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Copyright © 2008 by the American Society for Biochemistry and Molecular Biology.
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