Department of Oral Biology, Dental College of Georgia, Augusta University, 1120 15th Street, Augusta, GA, 30912, USA.
Emory Children's Center, Emory University, Atlanta, GA, USA.
Cell Oncol (Dordr). 2018 Feb;41(1):85-91. doi: 10.1007/s13402-017-0354-4. Epub 2017 Oct 5.
Hepatocellular carcinoma (HCC), a primary neoplasm derived from hepatocytes, is the second leading cause of cancer mortality worldwide. Previous work has shown that fibroblast growth factor 19 (FGF19), an oncogenic driver, acts as a negative regulator of the therapeutic efficacy of the tyrosine kinase inhibitor sorafenib in HCC cells. The FGF19-mediated mechanism affecting sorafenib treatment, however, still remains to be resolved. Here, we hypothesize that the FGF19-FGFR4 axis may affect the effectiveness of sorafenib in the treatment of HCC.
FGF19 and FGFR4 cDNAs were cloned into a pcDNA3.1 vector and subsequently used for exogenous over-expression analyses. FGF19 knockdown cells were generated using a lentiviral-mediated short hairpin RNA (shRNA) methodology and FGFR4 knockout cells were generated using a CRISPR-Cas9 methodology. FGFR4 activation in HCC cells was inhibited by BLU9931. The effects of exogenous gene over-expression, expression knockdown and knockout, as well as drug efficacies in HCC cells, were validated using Western blotting. HCC cell proliferation was assessed using a CellTiter 96 AQueous One Solution Cell Proliferation Assay, whereas NO levels were assessed using DAF-FM DA staining in conjunction with electrochemical biosensors.
We found that FGF19, when exogenously overexpressed, results in a reduced sorafenib-induced NO generation and a decreased proliferation of HCC cells. In contrast, we found that either FGF19 silencing or knockout of its receptor FGFR4 sensitized HCC cells to sorafenib through the induction of NO generation. Concordantly, we found that inactivation of FGFR4 by BLU9931 enhanced the sensitivity of HCC cells to sorafenib.
From our data we conclude that the FGF19-FGFR4 axis may play a critical role in the effects elicited by sorafenib in HCC cells. Blocking the FGF19-FGFR4 axis may provide novel opportunities to improve the efficacy of sorafenib in the treatment of patients with HCC.
肝细胞癌（HCC）是一种源自肝细胞的原发性肿瘤，是全球癌症死亡的第二大主要原因。先前的研究表明，成纤维细胞生长因子 19（FGF19）作为致癌驱动因子，可作为 HCC 细胞中酪氨酸激酶抑制剂索拉非尼治疗疗效的负调节剂。然而，FGF19 介导的影响索拉非尼治疗的机制仍有待解决。在这里，我们假设 FGF19-FGFR4 轴可能会影响索拉非尼治疗 HCC 的效果。
将 FGF19 和 FGFR4 cDNA 克隆到 pcDNA3.1 载体中，随后用于外源性过表达分析。使用慢病毒介导的短发夹 RNA（shRNA）方法生成 FGF19 敲低细胞，使用 CRISPR-Cas9 方法生成 FGFR4 敲除细胞。使用 BLU9931 抑制 HCC 细胞中的 FGFR4 激活。使用 Western blot 验证外源性基因过表达、表达敲低和敲除以及 HCC 细胞中的药物疗效。使用 CellTiter 96 AQueous One Solution 细胞增殖测定法评估 HCC 细胞增殖，使用 DAF-FM DA 染色结合电化学生物传感器评估 NO 水平。
我们发现，FGF19 在外源性过表达时，会导致索拉非尼诱导的 NO 生成减少和 HCC 细胞增殖减少。相反，我们发现，FGF19 沉默或其受体 FGFR4 敲除通过诱导 NO 生成使 HCC 细胞对索拉非尼敏感。一致地，我们发现，BLU9931 使 FGFR4 失活增强了 HCC 细胞对索拉非尼的敏感性。
根据我们的数据，我们得出结论，FGF19-FGFR4 轴可能在索拉非尼在 HCC 细胞中产生的作用中发挥关键作用。阻断 FGF19-FGFR4 轴可能为提高索拉非尼治疗 HCC 患者的疗效提供新的机会。
