Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada.
Int J Cancer. 2010 Aug 1;127(3):521-31. doi: 10.1002/ijc.25068.
The functional role of INSL3 and its receptor RXFP2 in carcinogenesis is largely unknown. We have previously demonstrated (pro-)cathepsin-L as a target of INSL3 in human thyroid cancer cells facilitating penetration of tumor cells through elastin matrices. We demonstrate the expression of RXFP2 in human thyroid tissues and in mouse follicular thyroid epithelial cells using Cre-recombinase transgene driven by Rxfp2 promoter. Recombinant and secreted INSL3 increased the motility of thyroid carcinoma (TC) cells in an autocrine/paracrine manner. This effect required the presence of RXFP2. We identified S100A4 as a novel INSL3 target molecule and showed that S100A4 facilitated INSL3-induced enhanced motility. Stable transfectants of the human follicular TC cell line FTC-133 expressing and secreting bioactive human INSL3 displayed enhanced anchorage-independent growth in soft agar assays. Xenotransplant experiments in nude mice showed that INSL3, but not EGFP-mock transfectants, developed fast-growing and highly vascularized xenografts. We used human umbilical vein endothelial cells in capillary tube formation assays to demonstrate increased 2-dimensional tube formations induced by recombinant human INSL3 and human S100A4 comparable to the effect of vascular endothelial growth factor used as positive control. We conclude that INSL3 is a powerful and multifunctional promoter of tumor growth and angiogenesis in human thyroid cancer cell xenografts. INSL3 actions involve RXFP2 activation and the secretion of S100A4 and (pro-)cathepsin-L.
胰岛素样肽 3（INSL3）及其受体 RXFP2 在肿瘤发生中的功能作用在很大程度上尚不清楚。我们之前已经证明（pro-）组织蛋白酶-L 是 INSL3 在人甲状腺癌细胞中的靶标，促进肿瘤细胞穿透弹性蛋白基质。我们使用由 Rxfp2 启动子驱动的 Cre 重组酶转基因在人甲状腺组织和小鼠滤泡甲状腺上皮细胞中证明了 RXFP2 的表达。重组和分泌的 INSL3 以自分泌/旁分泌的方式增加甲状腺癌（TC）细胞的迁移能力。这种作用需要 RXFP2 的存在。我们鉴定了 S100A4 作为 INSL3 的一种新的靶标分子，并表明 S100A4 促进了 INSL3 诱导的增强的迁移能力。表达和分泌生物活性人 INSL3 的人滤泡性 TC 细胞系 FTC-133 的稳定转染子在软琼脂测定中显示出增强的非依赖性生长。裸鼠异种移植实验表明，INSL3 而非 EGFP-模拟转染子形成快速生长和高度血管化的异种移植物。我们使用人脐静脉内皮细胞在毛细血管管形成测定中证明了重组人 INSL3 和人 S100A4 诱导的 2 维管形成增加，与用作阳性对照的血管内皮生长因子的作用相当。我们得出结论，INSL3 是人类甲状腺癌细胞异种移植物中肿瘤生长和血管生成的强大多功能促进剂。INSL3 的作用涉及 RXFP2 激活以及 S100A4 和（pro-）组织蛋白酶-L 的分泌。
