Transforming growth factor-β promotes survival of mammary carcinoma cells through induction of antiapoptotic transcription factor DEC1

Abstract

Transforming growth factor-β (TGF-β) signaling facilitates tumor growth and metastasis in advanced cancer. In the present study, we identified differentially expressed in chondrocytes 1 (DEC1, also known as SHARP2 and Stra13) as a downstream target of TGF-β signaling, which promotes the survival of breast cancer cells. In the mouse mammary carcinoma cell lines JygMC(A) and 4T1, the TGF-β type I receptor kinase inhibitors A-44-03 and SB431542 induced apoptosis of cells under serum-free conditions. Oligonucleotide microarray and real-time reverse transcription-PCR analyses revealed that TGF-β induced DEC1 in these cells, and the increase of DEC1 was suppressed by the TGF-β type I receptor kinase inhibitors as well as by expression of dominant-negative TGF-β type II receptor. Overexpression of DEC1 prevented the apoptosis of JygMC(A) cells induced by A-44-03, and knockdown of endogenous DEC1 abrogated TGF-β-promoted cell survival. Moreover, a dominant-negative mutant of DEC1 prevented lung and liver metastasis of JygMC(A) cells in vivo. Our observations thus provide new insights into the molecular mechanisms governing TGF-β-mediated cell survival and metastasis of cancer. ©2007 American Association for Cancer Research.