ROBO1, a tumor suppressor and critical molecular barrier for localized tumor cells to acquire invasive phenotype: study in African-American and Caucasian prostate cancer models.
ROBO1, a tumor suppressor and critical molecular barrier for localized tumor cells to acquire invasive phenotype: study in African-American and Caucasian prostate cancer models.
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DOI：
10.1002/ijc.28919
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发表时间：
2014-12-01
影响因子：
6.4
通讯作者：
Saleem M
中科院分区：
文献类型：
--
作者：
Parray A;Siddique HR;Kuriger JK;Mishra SK;Rhim JS;Nelson HH;Aburatani H;Konety BR;Koochekpour S;Saleem M
高危人群表现出局限性前列腺癌（CaP）疾病向转移的早期转化，导致这类患者的死亡。对原发肿瘤细胞获得转移行为的分子机制缺乏了解以及缺乏可靠的表型区分生物标志物是CaP疾病管理的绊脚石。在这里，我们确定了ROBO1（一种器官发生相关基因）在人类CaP中的作用和翻译相关性。利用CaP进展模型和白人和非裔美国患者的前列腺组织，我们发现ROBO1的表达局限于细胞膜，在原发性和转移性肿瘤中明显缺失。虽然高加索人在原发性和转移性表型中表现出相似的ROBO1水平，但在非裔美国人的肿瘤表型中观察到显著差异。表观遗传学分析鉴定了非裔美国人转移性CaP细胞特异性的ROBO1启动子甲基化。通过对非裔美国人CaP模型的进一步研究，我们发现ROBO1负性调节原代CaP细胞的运动和侵袭性，其缺失导致这些细胞获得侵袭性特征。为了了解潜在的机制，我们采用了robo1表达/ robo1 - c2c3突变体构建、免疫沉淀、共聚焦显微镜和荧光素酶报告技术。我们发现ROBO1通过与DOCK1（在sh3 - sh2结构域）的相互作用控制rac -激活。然而，ROBO1的缺失导致rac1激活，进而导致E-Cadherin/β-catenin细胞骨架不稳定并诱导细胞迁移。我们认为，ROBO1是一种预测性生物标志物，具有区分CaP类型的潜力，可以作为抑制疾病进展和治疗高危人群（如非洲裔美国人）转移的分子靶点。
High-risk populations exhibit early transformation of localized prostate cancer (CaP) disease to metastasis which results in the mortality of such patients. The paucity of knowledge about the molecular mechanism involved in acquiring of metastatic behavior by primary tumor cells and non-availability of reliable phenotype-discriminating biomarkers are stumbling blocks in the management of CaP disease. Here, we determine the role and translational relevance of ROBO1 (an organogenesis-associated gene) in human CaP. Employing CaP-progression models and prostatic tissues of Caucasian and African-American patients, we show that ROBO1 expression is localized to cell-membrane and significantly lost in primary and metastatic tumors. While Caucasians exhibited similar ROBO1 levels in primary and metastatic phenotype, a significant difference was observed between tumor phenotypes in African-Americans. Epigenetic assays identified promoter methylation of ROBO1 specific to African-American metastatic CaP cells. Using African-American CaP models for further studies, we show that ROBO1 negatively regulates motility and invasiveness of primary CaP cells, and its loss causes these cells to acquire invasive trait. To understand the underlying mechanism, we employed ROBO1-expressing/ROBO1-C2C3-mutant constructs, immunoprecipitation, confocal-microscopy and luciferase-reporter techniques. We show that ROBO1 through its interaction with DOCK1 (at SH3-SH2-domain) controls the Rac-activation. However, loss of ROBO1 results in Rac1-activation which in turn causes E-Cadherin/β-catenin cytoskeleton destabilization and induction of cell migration. We suggest that ROBO1 is a predictive biomarker that has potential to discriminate among CaP types, and could be exploited as a molecular target to inhibit the progression of disease as well as treat metastasis in high-risk populations such as African-Americans.