Wang Wei-Min, Xu Yang, Wang Yao-Hui, Sun Hai-Xiang, Sun Yun-Fan, He Yi-Feng, Zhu Qing-Feng, Hu Bo, Zhang Xin, Xia Jing-Lin, Qiu Shuang-Jian, Zhou Jian, Yang Xin-Rong, Fan Jia
Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Shanghai 200032, P. R. China.
Institute of Biomedical Sciences, Fudan University, Shanghai 200032, P. R. China.
Oncotarget. 2017 Jul 18;8(29):47121-47135. doi: 10.18632/oncotarget.17004.
The homeobox-containing gene HOXB7 plays an important role in the pathogenesis and progression of many cancers, yet its role in hepatocellular carcinoma (HCC) remains unclear. This study comprehensively analyzed the expression and clinical significance of HOXB7 in HCC and explored its potential mechanism in tumor progression. We found HOXB7 was highly expressed in HCC cell lines with highly metastatic potential and cancerous tissues from patients with tumor recurrence. The abilities of proliferation, migration, and invasion were notably decreased by depletion of HOXB7, and were enhanced by its enforced expression in vitro. HOXB7 expression was positively correlated with tumor progression and lung metastasis in vivo. The gene microarray data implied that HOXB7 affects biological functions of HCC cells through MAPK/ERK pathway activation. Further study confirmed that the effect of HOXB7 in activating MAPK/ERK pathway via induction of basic fibroblast growth factor (bFGF) secretion, and the inhibition of bFGF secretion could abolish MAPK/ERK pathway activation after ectopic expression of HOXB7. Chromatin immunoprecipitation experiments and luciferase reporter assays confirmed that HOXB7 promoted bFGF secretion via binding its promoter directly. Furthermore, the clinical significance of HOXB7 expression was confirmed using tissue microarrays containing 394 HCC tissue specimens. Patients with high HOXB7 expression showed shorter survival times and higher recurrence rates, and HOXB7 was an independent indicator for survival and recurrence. Overall, HOXB7 promotes HCC cell proliferation, migration, and invasion through the bFGF-induced MAPK/ERK pathway activation. It might be a novel prognostic factor in HCC and a promising therapeutic target for tumor metastasis and recurrence.
含同源框基因HOXB7在多种癌症的发病机制和进展中发挥重要作用,但其在肝细胞癌(HCC)中的作用仍不清楚。本研究全面分析了HOXB7在HCC中的表达及临床意义,并探讨了其在肿瘤进展中的潜在机制。我们发现HOXB7在具有高转移潜能的HCC细胞系以及肿瘤复发患者的癌组织中高表达。敲低HOXB7后,细胞的增殖、迁移和侵袭能力显著降低,而在体外过表达HOXB7则增强了这些能力。HOXB7的表达在体内与肿瘤进展和肺转移呈正相关。基因芯片数据表明,HOXB7通过激活MAPK/ERK信号通路影响HCC细胞的生物学功能。进一步研究证实,HOXB7通过诱导碱性成纤维细胞生长因子(bFGF)分泌来激活MAPK/ERK信号通路,抑制bFGF分泌可消除HOXB7异位表达后对MAPK/ERK信号通路的激活。染色质免疫沉淀实验和荧光素酶报告基因检测证实,HOXB7通过直接结合其启动子促进bFGF分泌。此外,使用包含394例HCC组织标本的组织芯片证实了HOXB7表达的临床意义。HOXB7高表达的患者生存时间较短,复发率较高,HOXB7是生存和复发的独立指标。总体而言,HOXB7通过bFGF诱导的MAPK/ERK信号通路激活促进HCC细胞的增殖、迁移和侵袭。它可能是HCC中一种新的预后因子,也是肿瘤转移和复发的一个有前景的治疗靶点。