Jeon Eun Su, Moon Hyun Jung, Lee Mi Jeong, Song Hae Young, Kim Young Mi, Cho Mong, Suh Dong-Soo, Yoon Man-Soo, Chang Chulhun L, Jung Jin Sup, Kim Jae Ho
Department of Physiology, School of Medicine, Pusan National University, 1-Ga, Ami-Dong, Suh-Gu, Busan 602-739, Republic of Korea.
Stem Cells. 2008 Mar;26(3):789-97. doi: 10.1634/stemcells.2007-0742. Epub 2007 Dec 6.
Lysophosphatidic acid (LPA) is enriched in ascites of ovarian cancer patients and is involved in growth and invasion of ovarian cancer cells. Accumulating evidence suggests cancer-associated myofibroblasts play a pivotal role in tumorigenesis through secreting stromal cell-derived factor-1 (SDF-1). In the present study, we demonstrate that LPA induces expression of alpha-smooth muscle actin (alpha-SMA), a marker for myofibroblasts, in human adipose tissue-derived mesenchymal stem cells (hADSCs). The LPA-induced expression of alpha-SMA was completely abrogated by pretreatment of the cells with Ki16425, an antagonist of LPA receptors, or by silencing LPA(1) or LPA(2) isoform expression with small interference RNA (siRNA). LPA elicited phosphorylation of Smad2/3, and siRNA-mediated depletion of endogenous Smad2/3 or adenoviral expression of Smad7, an inhibitory Smad, abrogated the LPA induced expression of alpha-SMA and phosphorylation of Smad2/3. LPA-induced secretion of transforming growth factor (TGF)-beta1 in hADSCs, and pretreatment of the cells with SB431542, a TGF-beta type I receptor kinase inhibitor, or anti-TGF-beta1 neutralizing antibody inhibited the LPA-induced expression of alpha-SMA and phosphorylation of Smad2. Furthermore, ascites from ovarian cancer patients or conditioned medium from ovarian cancer cells induced expression of alpha-SMA and phosphorylation of Smad2, and pretreatment of the cells with Ki16425 or SB431542 abrogated the expression of alpha-SMA and phosphorylation of Smad2. In addition, LPA increased the expression of SDF-1 in hADSCs, and pretreatment of the cells with Ki16425 or SB431562 attenuated the LPA-stimulated expression of SDF-1. These results suggest that cancer-derived LPA stimulates differentiation of hADSCs to myofibroblast-like cells and increases SDF-1 expression through activating autocrine TGF-beta1-Smad signaling pathway.
溶血磷脂酸（LPA）在卵巢癌患者的腹水中含量丰富，并参与卵巢癌细胞的生长和侵袭。越来越多的证据表明，癌症相关的肌成纤维细胞通过分泌基质细胞衍生因子-1（SDF-1）在肿瘤发生中起关键作用。在本研究中，我们证明LPA可诱导人脂肪组织来源的间充质干细胞（hADSCs）中肌成纤维细胞标志物α-平滑肌肌动蛋白（α-SMA）的表达。用LPA受体拮抗剂Ki16425预处理细胞，或用小干扰RNA（siRNA）沉默LPA(1)或LPA(2)亚型表达，可完全消除LPA诱导的α-SMA表达。LPA引起Smad2/3磷酸化，siRNA介导的内源性Smad2/3缺失或抑制性Smad Smad7的腺病毒表达可消除LPA诱导的α-SMA表达和Smad2/3磷酸化。LPA诱导hADSCs分泌转化生长因子（TGF）-β1，用TGF-β I型受体激酶抑制剂SB431542或抗TGF-β1中和抗体预处理细胞可抑制LPA诱导的α-SMA表达和Smad2磷酸化。此外，卵巢癌患者的腹水或卵巢癌细胞的条件培养基可诱导α-SMA表达和Smad2磷酸化，用Ki16425或SB431542预处理细胞可消除α-SMA表达和Smad2磷酸化。此外，LPA增加hADSCs中SDF-1的表达，用Ki16425或SB431562预处理细胞可减弱LPA刺激的SDF-1表达。这些结果表明，癌症来源的LPA通过激活自分泌TGF-β1-Smad信号通路刺激hADSCs向肌成纤维细胞样细胞分化并增加SDF-1表达。
