Medical Research Center for Ischemic Tissue Regeneration and Medical Research Institute, Pusan National University, Yangsan 626-870, Gyeongsangnam-do, Republic of Korea.
Mol Cell Proteomics. 2012 Feb;11(2):M111.012385. doi: 10.1074/mcp.M111.012385. Epub 2011 Dec 7.
Lysophosphatidic acid (LPA) is enriched in the serum and malignant effusion of cancer patients and plays a key role in tumorigenesis and metastasis. LPA-activated mesenchymal stem cells promote tumorigenic potentials of cancer cells through a paracrine mechanism. LPA-conditioned medium (LPA CM) from human adipose tissue-derived mesenchymal stem cells (hASCs) elicited adhesion and proliferation of A549 human lung adenocarcinoma cells. To identify proteins involved in the LPA-stimulated paracrine functions of hASCs, we analyzed the LPA CM using liquid-chromatography tandem mass spectrometry-based shotgun proteomics. We identified βig-h3, an extracellular matrix protein that is implicated in tumorigenesis and metastasis, as an LPA-induced secreted protein in hASCs. LPA-induced βig-h3 expression was abrogated by pretreating hASCs with the LPA receptor(1/3) inhibitor Ki16425 or small interfering RNA-mediated silencing of endogenous LPA(1). LPA-induced βig-h3 expression was blocked by treating the cells with the Rho kinase inhibitor Y27632, implying that LPA-induced βig-h3 expression is mediated by the LPA(1)- Rho kinase pathway. Immunodepletion or siRNA-mediated silencing of βig-h3 abrogated LPA CM-stimulated adhesion and proliferation of A549 cells, whereas retroviral overexpression of βig-h3 in hASCs potentiated it. Furthermore, recombinant βig-h3 protein stimulated the proliferation and adhesion of A549 human lung adenocarcinoma cells. These results suggest that hASC-derived βig-h3 plays a key role in tumorigenesis by stimulating the adhesion and proliferation of cancer cells and it can be applicable as a biomarker and therapeutic target for lung cancer.
溶血磷脂酸（LPA）在癌症患者的血清和恶性积液中富集，并在肿瘤发生和转移中发挥关键作用。LPA 激活的间充质干细胞通过旁分泌机制促进癌细胞的致瘤潜能。来自人脂肪组织来源的间充质干细胞（hASC）的 LPA 条件培养基（LPA CM）引起 A549 人肺腺癌细胞的黏附和增殖。为了鉴定参与 LPA 刺激 hASC 旁分泌功能的蛋白质，我们使用基于液相色谱串联质谱的鸟枪法蛋白质组学分析了 LPA CM。我们鉴定出βig-h3，一种细胞外基质蛋白，与肿瘤发生和转移有关，是 hASC 中 LPA 诱导的分泌蛋白。用 LPA 受体（1/3）抑制剂 Ki16425 预处理 hASC 或用内源性 LPA（1）的小干扰 RNA 沉默可阻断 LPA 诱导的βig-h3 表达。用 Rho 激酶抑制剂 Y27632 处理细胞可阻断 LPA 诱导的βig-h3 表达，表明 LPA 诱导的βig-h3 表达是由 LPA（1）-Rho 激酶途径介导的。βig-h3 的免疫耗竭或 siRNA 介导的沉默可阻断 LPA CM 刺激的 A549 细胞的黏附和增殖，而 hASC 中βig-h3 的逆转录病毒过表达则增强了其作用。此外，重组βig-h3 蛋白刺激 A549 人肺腺癌细胞的增殖和黏附。这些结果表明，hASC 衍生的βig-h3 通过刺激癌细胞的黏附和增殖在肿瘤发生中起关键作用，它可以作为肺癌的生物标志物和治疗靶点。
