Calvo Natalia, Carriere Pedro, Martin María Julia, Gentili Claudia
Departamento de BiologíaBioquímica y Farmacia, INBIOSUR, Universidad Nacional del Sur (UNS) - CONICET, Bahía Blanca, Argentina.
Departamento de BiologíaBioquímica y Farmacia, INBIOSUR, Universidad Nacional del Sur (UNS) - CONICET, Bahía Blanca, Argentina
J Mol Endocrinol. 2017 Jul;59(1):13-27. doi: 10.1530/JME-16-0216. Epub 2017 Apr 6.
Parathyroid hormone-related peptide (PTHrP) is associated with several human cancers such as colon carcinoma. This disease is a complex multistep process that involves enhanced cell cycle progression and migration. Recently we obtained evidence that in the human colorectal adenocarcinoma Caco2 cells, exogenous PTHrP increases the proliferation and positively modulates cell cycle progression via ERK1/2, p38 MAPK and PI3K. The purpose of this study was to explore if the serine/threonine kinase RSK, which is involved in the progress of many cancers and it is emerging as a potential therapeutic target, mediates PTHrP effects on cancer colon cells. Western blot analysis revealed that PTHrP increases RSK phosphorylation via ERK1/2 signaling pathway but not through p38 MAPK. By performing subcellular fractionation, we found that the peptide also induces the nuclear localization of activated RSK, where many of its substrates are located. RSK participates in cell proliferation, in the upregulation of cyclin D1 and CDK6 and in the downregulation of p53 induced by PTHrP. Wound healing and transwell filter assays revealed that cell migration increased after PTHrP treatment. In addition, the hormone increases the protein expression of the focal adhesion kinase FAK, a regulator of cell motility. We observed that PTHrP induces cell migration and modulates FAK protein expression through ERK/RSK signaling pathway but not via p38 MAPK pathway. Finally, studies revealed that the hormone activates RSK in xenografts tumor. Taken together, our findings provide new insights into the deregulated cell cycle and migration that is characteristic of tumor intestinal cells.
甲状旁腺激素相关肽（PTHrP）与多种人类癌症相关，如结肠癌。这种疾病是一个复杂的多步骤过程，涉及细胞周期进程加快和迁移增强。最近我们获得的证据表明，在人结肠腺癌Caco2细胞中，外源性PTHrP通过ERK1/2、p38丝裂原活化蛋白激酶（MAPK）和磷脂酰肌醇-3-激酶（PI3K）增加细胞增殖并正向调节细胞周期进程。本研究的目的是探讨丝氨酸/苏氨酸激酶RSK是否介导PTHrP对结肠癌细胞的作用，RSK参与多种癌症的进展并正成为一个潜在的治疗靶点。蛋白质印迹分析显示，PTHrP通过ERK1/2信号通路而非p38 MAPK增加RSK磷酸化。通过进行亚细胞分级分离，我们发现该肽还诱导活化的RSK的核定位，其许多底物位于细胞核中。RSK参与PTHrP诱导的细胞增殖、细胞周期蛋白D1和细胞周期蛋白依赖性激酶6（CDK6）的上调以及p53的下调。伤口愈合和Transwell小室分析显示，PTHrP处理后细胞迁移增加。此外，该激素增加粘着斑激酶（FAK）的蛋白表达，FAK是细胞运动的调节因子。我们观察到，PTHrP通过ERK/RSK信号通路而非p38 MAPK途径诱导细胞迁移并调节FAK蛋白表达。最后，研究显示该激素在异种移植瘤中激活RSK。综上所述，我们的研究结果为肿瘤肠细胞特有的细胞周期失调和迁移提供了新的见解。
