Lysophosphatidic Acid-Induced p21(Waf1) Expression Mediates the Cytostatic Response of Breast and Ovarian Cancer Cells to TGF beta

作者：Wu Jinhua; Mukherjee Abir; Lebman Deborah A; Fang Xianjun^*

来源：Molecular Cancer Research, 2011, 9(11): 1562-1570.

DOI：10.1158/1541-7786.MCR-11-0340

Lysophosphatidic acid (LPA) is a multifunctional intercellular phospholipid mediator present in blood and other biological fluids. In cancer cells, LPA stimulates expression or activity of inflammatory cytokines, angiogenic factors, matrix metalloproteinases, and other oncogenic proteins. In this study, we showed that LPA upregulated expression of the cyclin-dependent kinase inhibitor p21(Waf1) in TGF beta-sensitive breast and ovarian cancer cells, but not in TGF beta-resistant ones. We examined the possibility that LPA-induced p21 might contribute to the cytostatic response to TGF beta. In serum-free conditions, TGF beta alone induced p21 expression weakly in TGF beta-sensitive cells. Serum or serum-borne LPA cooperated with TGF beta to elicit the maximal p21 induction. LPA stimulated p21 via LPA(1) and LPA(2) receptors and Erk-dependent activation of the CCAAT/enhancer binding protein beta transcription factor independent of p53. Loss or gain of p21 expression led to a shift between TGF beta-sensitive and -resistant phenotypes in breast and ovarian cancer cells, indicating that p21 is a key determinant of the growth inhibitory activity of TGF beta. Our results reveal a novel cross-talk between LPA and TGF beta that underlies TGF beta-sensitive and -resistant phenotypes of breast and ovarian cancer cells. Mol Cancer Res; 9(11); 1562-70.

• 出版日期2011-11