Dall'Agnol Monique, Bernstein Carol, Bernstein Harris, Garewal Harinder, Payne Claire M
Department of Cell Biology and Anatomy, College of Medicine, University of Arizona, Tucson, AZ, USA.
Proteomics. 2006 Mar;6(5):1654-62. doi: 10.1002/pmic.200500240.
Apoptosis resistance, a condition favoring genomic instability, is associated with higher risk of colorectal cancer. Deoxycholate (DOC) is a hydrophobic bile salt found in high concentrations in colon cancer patients, and induces apoptosis in cultured colonic cells and ex vivo in colonic biopsies. We showed previously that the chronic exposure of colon cancer cells to increasing concentrations of DOC leads to apoptosis resistance, and the suggested mechanism involves oxidative/nitrosative stress. Nitric oxide (NO) is a key signaling molecule that regulates cell function in a variety of physiologic and pathophysiologic states. In part, NO exerts its actions by S-nitrosylation of target thiols, and several proteins are regulated through this PTM, including the caspases, the main effectors of apoptosis. Here, we performed a proteomics study in the DOC-induced apoptosis-resistant colon cell line, HCT-116RC. Its profile of S-nitrosylated proteins was compared to a control cell line not exposed to DOC. Eighteen differentially S-nitrosylated proteins were identified in the HCT-116RC cell line, 14 of these are novel targets of S-nitrosylation not previously reported. These proteins include cytoskeletal and signaling proteins, metabolic enzymes, chaperones, and redox- and differentiation-related proteins. These results broaden our knowledge of potential signal transduction pathways that may lead to the development of new biomarkers and therapy targets.
凋亡抗性是一种有利于基因组不稳定的状态，与结直肠癌的高风险相关。脱氧胆酸盐（DOC）是一种疏水性胆汁盐，在结肠癌患者中浓度较高，并能在培养的结肠细胞和结肠活检组织中诱导凋亡。我们之前表明，结肠癌细胞长期暴露于浓度不断增加的DOC会导致凋亡抗性，推测的机制涉及氧化/亚硝化应激。一氧化氮（NO）是一种关键的信号分子，在多种生理和病理生理状态下调节细胞功能。部分情况下，NO通过靶硫醇的S-亚硝基化发挥作用，几种蛋白质通过这种翻译后修饰受到调控，包括凋亡的主要效应分子半胱天冬酶。在此，我们在DOC诱导的凋亡抗性结肠癌细胞系HCT-116RC中进行了蛋白质组学研究。将其S-亚硝基化蛋白质谱与未暴露于DOC的对照细胞系进行比较。在HCT-116RC细胞系中鉴定出18种差异S-亚硝基化蛋白质，其中14种是以前未报道的S-亚硝基化新靶点。这些蛋白质包括细胞骨架和信号蛋白、代谢酶、分子伴侣以及与氧化还原和分化相关的蛋白质。这些结果拓宽了我们对潜在信号转导途径的认识，可能会导致新生物标志物和治疗靶点的开发。
