Cancer Program, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, Queensland 4059, Australia.
Gynecol Oncol. 2012 Dec;127(3):569-78. doi: 10.1016/j.ygyno.2012.09.001. Epub 2012 Sep 8.
Chemoresistance is a critical feature of advanced ovarian cancer with only 30% of patients surviving longer than 5 years. We have previously shown that four kallikrein-related (KLK) peptidases, KLK4, KLK5, KLK6 and KLK7 (KLK4-7), are implicated in peritoneal invasion and tumour growth, but underlying mechanisms were not identified. We also reported that KLK7 overexpression confers chemoresistance to paclitaxel, and cell survival via integrins. In this study, we further explored the functional consequenses of overexpression of all four KLKs (KLK4-7) simultaneously in the ovarian cancer cell line, OV-MZ-6, and its impact on integrin expression and signalling, cell adhesion and survival as contributors to chemoresistance and metastatic progression.
Quantitative gene and protein expression analyses, confocal microscopy, cell adhesion and chemosensitivity assays were performed.
Expression of α5β1/αvβ3 integrins was downregulated upon combined stable KLK4-7 overexpression in OV-MZ-6 cells. Accordingly, the adhesion of these cells to vitronectin and fibronectin, the extracellular matrix binding proteins of α5β1/αvβ3 integrins and two predominant proteins of the peritoneal matrix, was decreased. KLK4-7-transfected cells were more resistant to paclitaxel (10-100 nmol/L: 38-54%), but not to carboplatin, which was associated with decreased apoptotic stimuli. However, the KLK4-7-induced paclitaxel resistance was not blocked by the MEK1/2 inhibitor, U0126.
This study demonstrates that combined KLK4-7 expression by ovarian cancer cells promotes reduced integrin expression with consequently less cell-matrix attachment, and insensitivity to paclitaxel mediated by complex integrin and MAPK independent interactions, indicative of a malignant phenotype and disease progression suggesting a role for these KLKs in this process.
化疗耐药性是晚期卵巢癌的一个关键特征，只有 30%的患者存活时间超过 5 年。我们之前已经表明，四种激肽释放酶相关（KLK）肽酶，KLK4、KLK5、KLK6 和 KLK7（KLK4-7），与腹膜侵犯和肿瘤生长有关，但未确定潜在机制。我们还报告说 KLK7 的过表达赋予紫杉醇耐药性，并通过整合素赋予细胞存活。在这项研究中，我们进一步探索了在卵巢癌细胞系 OV-MZ-6 中同时过表达所有四种 KLK（KLK4-7）的功能后果，及其对整合素表达和信号转导、细胞黏附和存活的影响，这些都是化疗耐药性和转移进展的贡献因素。
进行了定量基因和蛋白质表达分析、共聚焦显微镜检查、细胞黏附和化学敏感性测定。
在 OV-MZ-6 细胞中稳定过表达 KLK4-7 时，α5β1/αvβ3 整合素的表达下调。相应地，这些细胞与 vitronectin 和 fibronectin 的黏附减少，vitronectin 和 fibronectin 是 α5β1/αvβ3 整合素的细胞外基质结合蛋白，也是腹膜基质中的两种主要蛋白。KLK4-7 转染的细胞对紫杉醇（10-100nmol/L：38-54%）更具耐药性，但对卡铂不耐药，这与凋亡刺激减少有关。然而，KLK4-7 诱导的紫杉醇耐药性不能被 MEK1/2 抑制剂 U0126 阻断。
本研究表明，卵巢癌细胞的 KLK4-7 联合表达促进了整合素表达的减少，从而导致细胞与基质的附着减少，以及对紫杉醇的不敏感，这是由复杂的整合素和 MAPK 非依赖性相互作用介导的，表明了一种恶性表型和疾病进展，表明这些 KLKs 在这一过程中起作用。
