Department of Pathogen Biology & Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.
Department of Hepatic Biliary Pancreatic Surgery, Cancer Hospital Affiliated to Zhengzhou University, Zhengzhou, China.
Liver Int. 2018 Nov;38(11):2006-2017. doi: 10.1111/liv.13757. Epub 2018 May 21.
The role of Ras guanine nucleotide-releasing protein 1 (RasGRP1) in tumourigenesis has been a subject of debate, and its functions and clinical significance in hepatocellular carcinoma (HCC) remain unknown. Here, we evaluated the expression of RasGRP1 in HCC and determined how it contributes to HCC cell proliferation.
RasGRP1 expression was measured by quantitative polymerase chain reaction (qPCR) and Western blotting of 24 paired HCC tissues and para-tumour tissues. RasGRP1 expression was confirmed by immunohistochemical analysis of a tissue microarray from 1 independent cohort. Overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method, and risk factors that contributed to OS or DFS were identified using Cox regression analysis. The biologic relevance of RasGRP1 was examined by small interfering RNAs and an exogenous plasmid construct. Chromatin immunoprecipitation assays were performed to examine the binding of Sp1 to the RasGRP1 promoter.
Increased RasGRP1 expression was associated with tumour size (P = .004), tumour-node-metastasis stage (P = .032), and Barcelona Clinic Liver Cancer stage (P = .002). RasGRP1 overexpression was an independent prognostic factor in HCC patients. RasGRP1 downregulation inhibited cell proliferation, whereas RasGRP1 overexpression promoted cell proliferation. Moreover, specificity protein 1 bound to the RasGRP1 promoter and promoted RasGRP1 transcription. In addition, RasGRP1 overexpression enhanced activation of the c-Raf pathway.
RasGRP1 is upregulated in HCC and promotes HCC cell proliferation. Thus, RasGRP1 may be a novel therapeutic target for HCC.
Ras 鸟嘌呤核苷酸释放蛋白 1（RasGRP1）在肿瘤发生中的作用一直存在争议，其在肝细胞癌（HCC）中的功能和临床意义尚不清楚。在这里，我们评估了 RasGRP1 在 HCC 中的表达，并确定了它如何促进 HCC 细胞增殖。
通过定量聚合酶链反应（qPCR）和 24 对 HCC 组织和癌旁组织的 Western 印迹测定 RasGRP1 的表达。通过来自 1 个独立队列的组织微阵列的免疫组织化学分析证实了 RasGRP1 的表达。使用 Kaplan-Meier 法估计总生存期（OS）和无病生存期（DFS），并使用 Cox 回归分析确定与 OS 或 DFS 相关的危险因素。通过小干扰 RNA 和外源性质粒构建来检查 RasGRP1 的生物学相关性。进行染色质免疫沉淀测定以检查 Sp1 与 RasGRP1 启动子的结合。
RasGRP1 表达增加与肿瘤大小（P=0.004）、肿瘤-淋巴结-转移分期（P=0.032）和巴塞罗那临床肝癌分期（P=0.002）相关。RasGRP1 过表达是 HCC 患者的独立预后因素。RasGRP1 下调抑制细胞增殖，而 RasGRP1 过表达促进细胞增殖。此外，特异性蛋白 1 与 RasGRP1 启动子结合并促进 RasGRP1 转录。此外，RasGRP1 过表达增强了 c-Raf 通路的激活。
RasGRP1 在 HCC 中上调并促进 HCC 细胞增殖。因此，RasGRP1 可能是 HCC 的一种新的治疗靶点。
