Up-Regulation of the Fibroblast Growth Factor 8 Subfamily in Human Hepatocellular Carcinoma for Cell Survival and Neoangiogenesis Δσ

Abstract

Fibroblast growth factors (FGFs) and their high-affinity receptors [fibroblast growth factor receptors (FGFRs)] contribute to autocrine and paracrine growth stimulation in several nonliver cancer entities. Here we report that at least one member of the FGF8 subfamily (FGF8, FGF17, and FGF18) was up-regulated in 59% of 34 human hepatocellular carcinoma (HCC) samples that we investigated. The levels of the corresponding receptors (FGFR2, FGFR3, and FGFR4) were also elevated in the great majority of the HCC cases. Overall, 82% of the HCC cases showed overexpression of at least one FGF and/or FGFR. The functional implications of the deregulated FGF/FGFR system were investigated by the simulation of an insufficient blood supply. When HCC-1.2, HepG2, or Hep3B cells were subjected to serum withdrawal or the hypoxia-mimetic drug deferoxamine mesylate, the expression of FGF8 subfamily members increased dramatically. In the serum-starved cells, the incidence of apoptosis was elevated, whereas the addition of FGF8, FGF17, or FGF18 impaired apoptosis, which was associated with phosphorylation of extracellular signal-regulated kinase 1/2 and ribosomal protein S6. In contrast, down-modulation of FGF18 by small interfering RNA (siRNA) significantly reduced the viability of the hepatocarcinoma cells. siRNA targeting FGF18 also impaired the cells' potential to form clones at a low cell density or in soft agar. With respect to the tumor microenvironment, FGF17 and FGF18 stimulated the growth of HCC-derived myofibroblasts, and FGF8, FGF17, and FGF18 induced the proliferation and tube formation of hepatic endothelial cells. Conclusion: FGF8, FGF17, and FGF18 are involved in autocrine and paracrine signaling in HCC and enhance the survival of tumor cells under stress conditions, malignant behavior, and neoangiogenesis. Thus, the FGF8 subfamily supports the development and progression of hepatocellular malignancy. (HEPATOLOGY 2011;53:854-864) H epatocellular carcinoma (HCC) is the thirdleading cause of cancer deaths worldwide. 1 Important risk factors for this disease are persistent infections with hepatitis viruses and chronic steatohepatitis due to ethanol abuse and obesity, which contribute to the increasing incidence of HCC in Abbreviations: AHR, aryl hydrocarbon receptor; AKT, protein kinase B; ERK, extracellular signal-regulated kinase; ETS, E twenty-six; FACS, fluorescenceactivated cell sorting; FBS, fetal bovine serum; FCS, fetal colf serum; FGF, fibroblast growth factor; FGFR, fibroblast growth factor receptor; GSK3b, glycogen synthase kinase 3b; HCC, hepatocellular carcinoma; HIF, hypoxia inducible factor; MAP, mitogen-activated protein; MF, myofibroblast; mRNA, messenger RNA; MTF, metal-responsive transcription factor; pERK, phosphorylated extracellular signal-regulated kinase; pGSK3b, phosphorylated glycogen synthase kinase 3b; pS6, phosphorylated S6; qRT-PCR, quantitative reverse-transcriptase polymerase chain reaction; siFGF18, small interfering RNA targeting fibroblast growth factor 18; siRNA, small interfering RNA;...

Cancer stem cells in the development of liver cancer

“…52). For example, signaling of FGF and Wnt is implicated in HCC development (53)(54)(55), and Wnt signaling regulates hepatoblasts and liver CSC self-renewal (18,(56)(57)(58)(59)(60). Recent application of massive parallel sequencing technologies have consistently confirmed previous findings that somatic mutations of genes in the Wnt/β-catenin signaling pathways, such as axin and β-catenin, are common HCC events (61)(62)(63).…”

Molecular Pathways: Fibroblast Growth Factor Signaling: A New Therapeutic Opportunity in Cancer

“…In vitro studies have shown that FGF5 overexpression has been associated with a number of tumor cell lines (lung, esophagus, melanoma, colon, and prostate; ref. 23), and in hepatocellular carcinomas (HCC), the upregulation of FGF2, 8, 17, and 18 initiates autocrine growth stimulation, cell survival, and neoangiogenesis (24)(25)(26)(27). Further, HCC has been found to develop in transgenic mice overexpressing the hormonal FGF19 (28), and FGF19 is found on an amplicon on chromosome 11q that also invariably contains the adjacent FGF3, FGF4, and Cyclin D1 (CCND1) genes.…”

The fibroblast growth factor receptor 2-mediated extracellular signal-regulated kinase 1/2 signaling pathway plays is important in regulating excision repair cross-complementary gene 1 expression in hepatocellular carcinoma

“…FGFR2 is the product of the Bek oncogene expression product and a transmembrane tyrosine kinase receptor with a high affinity for a variety of FGFs (8). Studies have demonstrated (13) that ERCC1 in HCC cells is the downstream target of MEK/ERK and PI3K.…”