FAK is required for c-Met/?-catenin-driven hepatocarcinogenesis.
ABSTRACT: Hepatocellular carcinoma (HCC) is the third most common cause of cancer death worldwide and most patients with HCC have limited treatment options. Focal adhesion kinase (FAK) is overexpressed in many HCC specimens, offering a potential target for HCC treatment. However, the role of FAK in hepatocarcinogenesis remains elusive. Establishing whether FAK expression plays a role in HCC development is necessary to determine whether it is a viable therapeutic target. In this study, we generated mice with hepatocyte-specific deletion of Fak and investigated the role of Fak in an oncogenic (c-MET/?-catenin, MET/CAT)-driven HCC model. We found that deletion of Fak in hepatocytes did not affect morphology, proliferation, or apoptosis. However, Fak deficiency significantly repressed MET/CAT-induced tumor development and prolonged survival of animals with MET/CAT-induced HCC. In mouse livers and HCC cell lines, Fak was activated by MET, which induced the activation of Akt/Erk and up-regulated cyclin D1 and tumor cell proliferation. CAT enhanced MET-stimulated FAK activation and synergistically induced the activation of the AKT/ERK-cyclin D1 signaling pathway in a FAK kinase-dependent manner. In addition, FAK was required for CAT-induced cyclin D1 expression in a kinase-independent fashion.Fak is required for c-Met/?-catenin-driven hepatocarcinogenesis. Inhibition of FAK provides a potential strategy to treat HCC.
Project description:Both activating and inactivating mutations in catenin ?1 (ctnnb1), which encodes ?-catenin, have been implicated in liver tumorigenesis in humans and mice, although the underlying mechanisms are not fully understood. Herein, we show that deletion of endogenous ?-catenin in hepatocytes aggravated hepatocellular carcinoma (HCC) development driven by an oncogenic version of ?-catenin (CAT) in combination with the hepatocyte growth factor receptor MET proto-oncogene receptor tyrosine kinase (MET). Although the mitogenic signaling and cell cycle progression was modestly impaired after CAT/MET transfection, the ?-catenin-deficient livers displayed changes in transcriptomes, increased DNA damage response, expanded Sox9+ cells, and up-regulation of protumorigenic cytokines, including interleukin-6 and transforming growth factor ?1. These events eventually exacerbated CAT/MET-driven hepatocarcinogenesis in ?-catenin-deficient livers, featured by up-regulation of extracellular signal-regulated kinase (Erk), protein kinase B (Akt), and Wnt/?-catenin signaling and cyclin D1 expression. The resultant mouse tumors showed similar transcriptomes to human HCC samples with concomitant CTNNB1 mutations and MET overexpression. CONCLUSION:These data argue that while dominantly activating mutants of ?-catenin are oncogenic, inhibiting the oncogenic signaling pathway generates a pro-oncogenic microenvironment that may facilitate HCC recurrence following a targeted therapy of the primary tumor. An effective therapeutic strategy must require disruption of the oncogenic signaling in tumor cells and suppression of the secondary tumor-promoting stromal effects in the liver microenvironment. (Hepatology 2018;67:1807-1822).
Project description:There is an urgent need to develop new and more effective therapeutic strategies and agents to treat hepatocellular carcinoma (HCC). We have recently found that deletion of Fak in hepatocytes before tumors form inhibits tumor development and prolongs survival of animals in a c-MET (MET)/?-catenin (CAT)-driven HCC mouse model. However, it has yet to be determined whether FAK expression in hepatocytes promotes MET/CAT-induced HCC progression after tumor initiation. In addition, it remains unclear whether FAK promotes HCC development through its kinase activity. We generated hepatocyte-specific inducible Fak-deficient mice (Alb-creERT2; Fak(flox/flox)) to examine the role of FAK in HCC progression. We reexpressed wild-type and mutant FAK in Fak-deficient mice to determine FAK's kinase activity in HCC development. We also examined the efficacy of a FAK kinase inhibitor PF-562271 on HCC inhibition. We found that deletion of Fak after tumors form significantly repressed MET/CAT-induced tumor progression. Ectopic FAK expression restored HCC formation in hepatocyte-specific Fak-deficient mice. However, overexpression of a FAK kinase-dead mutant led to reduced tumor load compared to mice that express wild-type FAK. Furthermore, PF-562271 significantly suppressed progression of MET/CAT-induced HCC. Fak kinase activity is important for MET/CAT-induced HCC progression. Inhibiting FAK kinase activity provides a potential therapeutic strategy to treat HCC.
Project description:Activation of c-Met signaling and beta-catenin mutations are frequent genetic events observed in liver cancer development. Recently, we demonstrated that activated beta-catenin can cooperate with c-Met to induce liver cancer formation in a mouse model. Cyclin D1 (CCND1) is an important cell cycle regulator that is considered to be a downstream target of beta-catenin. To determine the importance of CCND1 as a mediator of c-Met- and beta-catenin-induced hepatocarcinogenesis, we investigated the genetic interactions between CCND1, beta-catenin, and c-Met in liver cancer development using mouse models. We coexpressed CCND1 with c-Met in mice and found CCND1 to cooperate with c-Met to promote liver cancer formation. Tumors induced by CCND1/c-Met had a longer latency period, formed at a lower frequency, and seemed to be more benign compared with those induced by beta-catenin/c-Met. In addition, when activated beta-catenin and c-Met were coinjected into CCND1-null mice, liver tumors developed despite the absence of CCND1. Intriguingly, we observed a moderate accelerated tumor growth and increased tumor malignancy in these CCND1-null mice. Molecular analysis showed an up-regulation of cyclin D2 (CCND2) expression in CCND1-null tumor samples, indicating that CCND2 may replace CCND1 in hepatic tumorigenesis. Together, our results suggest that CCND1 functions as a mediator of beta-catenin during HCC pathogenesis, although other molecules may be required to fully propagate beta-catenin signaling. Moreover, our data suggest that CCND1 expression is not essential for liver tumor development induced by c-Met and beta-catenin.
Project description:There is an urgent need to understand the molecular signaling pathways that drive or mediate the development of hepatocellular carcinoma (HCC). The focal adhesion kinase (FAK) gene protein tyrosine kinase 2 is amplified in 16.4% of The Cancer Genome Atlas HCC specimens, and its amplification leads to increased FAK mRNA expression. It is not known whether the overexpression of FAK alone is sufficient to induce HCC or whether it must cooperate in some ways with other oncogenes. In this study, we found that 34.8% of human HCC samples with FAK amplification also show ?-catenin mutations, suggesting a co-occurrence of FAK overexpression and ?-catenin mutations in HCC. We overexpressed FAK alone, constitutively active forms of ?-catenin (CAT) alone, or a combination of FAK and CAT in the livers of C57/BL6 mice. We found that overexpression of both FAK and CAT, but neither FAK nor CAT alone, in mouse livers was sufficient to lead to tumorigenesis. We further demonstrated that FAK's kinase activity is required for FAK/CAT-induced tumorigenesis. Furthermore, we performed RNA-sequencing analysis to identify the genes/signaling pathways regulated by FAK, CAT, or FAK/CAT. We found that FAK overexpression dramatically enhances binding of ?-catenin to the promoter of androgen receptor (AR), which leads to increased expression of AR in mouse livers. Moreover, ASC-J9, an AR degradation enhancer, suppressed FAK/CAT-induced HCC formation. Conclusion: FAK overexpression and ?-catenin mutations often co-occur in human HCC tissues. Co-overexpression of FAK and CAT leads to HCC formation in mice through increased expression of AR; this mouse model may be useful for further studies of the molecular mechanisms in the pathogenesis of HCC and could lead to the identification of therapeutic targets.
Project description:BACKGROUND & AIMS:Shp2 is an SH2-tyrosine phosphatase acting downstream of receptor tyrosine kinases (RTKs). Most recent data demonstrated a liver tumor-suppressing role for Shp2, as ablating Shp2 in hepatocytes aggravated hepatocellular carcinoma (HCC) induced by chemical carcinogens or Pten loss. We further investigated the effect of Shp2 deficiency on liver tumorigenesis driven by classical oncoproteins c-Met (receptor for HGF), ?-catenin and PIK3CA. METHODS:We performed hydrodynamic tail vein injection of two pairs of plasmids expressing c-Met and ?N90-?-catenin (MET/CAT), or c-Met and PIK3CAH1047R (MET/PIK), into WT and Shp2hep-/- mice. We compared liver tumor loads and investigated the pathogenesis and molecular mechanisms involved using multidisciplinary approaches. RESULTS:Despite the induction of oxidative and metabolic stresses, Shp2 deletion in hepatocytes suppressed hepatocarcinogenesis driven by overexpression of oncoproteins MET/CAT or MET/PIK. Shp2 loss inhibited proliferative signaling from c-Met, Wnt/?-catenin, Ras/Erk and PI3K/Akt pathways, but triggered cell senescence following exogenous expression of the oncogenes. CONCLUSIONS:Shp2, acting downstream of RTKs, is positively required for hepatocyte-intrinsic tumorigenic signaling from these oncoproteins, even if Shp2 deficiency induces a tumor-promoting hepatic microenvironment. These data suggest a new and more effective therapeutic strategy for HCCs driven by oncogenic RTKs and other upstream molecules, by inhibiting Shp2 and also suppressing any tumor-enhancing stromal factors produced because of Shp2 inhibition. LAY SUMMARY:Primary liver cancer is a malignant disease with poor prognosis, largely because there are limited systemic therapies available. We show here that a cytoplasmic tyrosine phosphatase Shp2 is required for liver tumorigenesis. This tumorigenesis is driven by two oncoproteins that are implicated in human liver cancer. This, together with our previous studies, uncovers the complexity of liver tumorigenesis, by elucidating the pro- and anti-tumor effects of Shp2 in mouse models. This data can be used to guide new therapies.
Project description:Hepatocellular carcinoma (HCC) is the most prevalent liver tumor and a deadly disease with limited therapeutic options. Dysregulation of cell signaling pathways is a common denominator in tumorigenesis, including hepatocarcinogenesis. The epidermal growth factor receptor (EGFR) signaling system is commonly activated in HCC, and is currently being evaluated as a therapeutic target in combination therapies. We and others have identified a central role for the EGFR ligand amphiregulin (AR) in the proliferation, survival and drug resistance of HCC cells. AR expression is frequently up-regulated in HCC tissues and cells through mechanisms not completely known. Here we identify the ?-catenin signaling pathway as a novel mechanism leading to transcriptional activation of the AR gene in human HCC cells. Activation of ?-catenin signaling, or expression of the T41A ?-catenin active mutant, led to the induction of AR expression involving three specific ?-catenin-Tcf responsive elements in its proximal promoter. We demonstrate that HCC cells expressing the T41A ?-catenin active mutant show enhanced proliferation that is dependent in part on AR expression and EGFR signaling. We also demonstrate here a novel cross-talk of the EGFR system with fibroblast growth factor 19 (FGF19). FGF19 is a recently identified driver gene in hepatocarcinogenesis and an activator of ?-catenin signaling in HCC and colon cancer cells. We show that FGF19 induced AR gene expression through the ?-catenin pathway in human HCC cells. Importantly, AR up-regulation and EGFR signaling participated in the induction of cyclin D1 and cell proliferation elicited by FGF19. Finally, we demonstrate a positive correlation between FGF19 and AR expression in human HCC tissues, therefore supporting in clinical samples our experimental observations. These findings identify the AR/EGFR system as a key mediator of FGF19 responses in HCC cells involving ?-catenin signaling, and suggest that combined targeting of FGF19 and AR/EGFR may enhance therapeutic efficacy.
Project description:Inactivating mutations of axis inhibition protein 1 (AXIN1), a negative regulator of the Wnt/?-Catenin cascade, are among the common genetic events in human hepatocellular carcinoma (HCC), affecting approximately 10% of cases. In the present manuscript, we sought to define the genetic crosstalk between Axin1 mutants and Wnt/?-catenin as well as Notch signaling cascades along hepatocarcinogenesis. We discovered that c-MET activation and AXIN1 mutations occur concomitantly in ~3%-5% of human HCC samples. Subsequently, we generated a murine HCC model by means of CRISPR/Cas9-based gene deletion of Axin1 (sgAxin1) in combination with transposon-based expression of c-Met in the mouse liver (c-Met/sgAxin1). Global gene expression analysis of mouse normal liver, HCCs induced by c-Met/sgAxin1, and HCCs induced by c-Met/?N90-?-Catenin revealed activation of the Wnt/?-Catenin and Notch signaling in c-Met/sgAxin1 HCCs. However, only a few of the canonical Wnt/?-Catenin target genes were induced in c-Met/sgAxin1 HCC when compared with corresponding lesions from c-Met/?N90-?-Catenin mice. To study whether endogenous ?-Catenin is required for c-Met/sgAxin1-driven HCC development, we expressed c-Met/sgAxin1 in liver-specific Ctnnb1 null mice, which completely prevented HCC development. Consistently, in AXIN1 mutant or null human HCC cell lines, silencing of ?-Catenin strongly inhibited cell proliferation. In striking contrast, blocking the Notch cascade through expression of either the dominant negative form of the recombinant signal-binding protein for immunoglobulin kappa J region (RBP-J) or the ablation of Notch2 did not significantly affect c-Met/sgAxin1-driven hepatocarcinogenesis. Conclusion: We demonstrated here that loss of Axin1 cooperates with c-Met to induce HCC in mice, in a ?-Catenin signaling-dependent but Notch cascade-independent way.
Project description:Mouse models of hepatocellular carcinoma (HCC) simulate specific subgroups of human HCC. We investigated hepatocarcinogenesis in Mdr2-KO mice, a model of inflammation-associated HCC, using gene expression profiling and immunohistochemical analyses. Gene expression profiling demonstrated that although Mdr2-KO mice differ from other published murine HCC models, they share several important deregulated pathways and many coordinately differentially expressed genes with human HCC datasets. Analysis of genome positions of differentially expressed genes in liver tumors revealed a prolonged region of down-regulated genes on murine chromosome 8 in three of the six analyzed tumor samples. This region is syntenic to human chromosomal regions that are frequently deleted in human HCC and harbor multiple tumor suppressor genes. Real-time RT-PCR analysis of 16 tumor samples confirmed down-regulation of several tumor suppressors in most tumors. We demonstrate that in the aged Mdr2-KO mice, cyclin D1 nuclear level is increased in dysplastic hepatocytes that do not form nodules; however, it is decreased in dysplastic nodules and in liver tumors. We found that this decrease is mostly at the protein, rather than the mRNA level. These findings raise the question on the role of cyclin D1 at early stages of hepatocarcinogenesis in the Mdr2-KO HCC model. Furthermore, we show that most liver tumors in Mdr2-KO mice were characterized by the absence of b-catenin activation. In conclusion, the Mdr2-KO mouse may serve as a model for b-catenin-negative subgroup of human HCCs characterized by low nuclear cyclin D1 levels in tumor cells and by down-regulation of multiple tumor suppressor genes. Experiment Overall Design: The liver RNA samples from six Mdr2-KO tumors, six non-tumorous liver tissues (four matched and two unmatched), as well as from three control heterozygous mice at 16 months of age were subjected to gene expression profiling using the genome scale Affymetrix Mouse Genome 430 2.0 Array.
Project description:The Wnt/beta-catenin pathway is implicated in the pathogenesis of hepatocellular cancer (HCC). We developed a transgenic mouse (TG) in the FVB strain that overexpresses Ser45-mutated-beta-catenin in hepatocytes to study the effects on liver regeneration and cancer. In the two independent TG lines adult mice show elevated beta-catenin at hepatocyte membrane with no increase in the Wnt pathway targets cyclin-D1 or glutamine synthetase. However, TG hepatocytes upon culture exhibit a 2-fold increase in thymidine incorporation at day 5 (D5) when compared to hepatocytes from wildtype FVB mice (WT). When subjected to partial hepatectomy (PH), dramatic increases in the number of hepatocytes in S-phase are evident in TG at 40 and WT at 72 hours. Coincident with the earlier onset of proliferation, we observed nuclear translocation of beta-catenin along with an increase in total and nuclear cyclin-D1 protein at 40 hours in TG livers. To test if stimulation of beta-catenin induces regeneration, we used hydrodynamic delivery of Wnt-1 naked DNA to control mice, which prompted an increase in Wnt-1, beta-catenin, and known targets, glutamine synthetase (GS) and cyclin-D1, along with a concomitant increase in cell proliferation. beta-Catenin-overexpressing TG mice, when followed up to 12 months, showed no signs of spontaneous tumorigenesis. However, intraperitoneal delivery of diethylnitrosamine (DEN), a known carcinogen, induced HCC at 6 months in TG mice only. Tumors in TG livers showed up-regulation of beta-catenin, cyclin-D1, and unique genetic aberrations, whereas other canonical targets were unremarkable.beta-Catenin overexpression offers growth advantage during liver regeneration. Also, whereas no spontaneous HCC is evident, beta-catenin overexpression makes TG mice susceptible to DEN-induced HCC.
Project description:Liver cancer occurs very frequently worldwide and hepatocellular carcinoma (HCC) accounts for more than 80% of total primary liver cancer cases. In this study, the anticarcinogenic effects of resveratrol against hepatitis B virus (HBV)-induced HCC were investigated by using HBV X-protein-overexpressing Huh7 (Huh7-HBx) human hepatoma cells. MTT assay showed that resveratrol decreased cell viability. Fluorescence-activated cell-sorter analysis showed that resveratrol induced G1 cell cycle arrest without increasing the sub-G1 phase cell population. Therefore, we evaluated its effect on regulation of cyclin D1, which is critically involved in G1/S transition. Resveratrol lowered cyclin D1 transcription. Western blot analysis of the effects of resveratrol on upstream cyclin D1 transcriptional signaling, extracellular signal-related kinase (ERK), p90RSK, Akt, and p70S6K revealed inhibition of Akt but not the ERK signaling pathway. Collectively, the results indicate that resveratrol inhibits Huh7-HBx proliferation by decreasing cyclin D1 expression through blockade of Akt signaling. We investigated the anticarcinogenic effect and mechanism of resveratrol in xenograft model mice implanted with Huh7-HBx cells. Intraperitoneal resveratrol injection reduced tumor size in the mice. Expression of survivin was reduced, but cyclin D1 was not affected. The results demonstrate that resveratrol treatment may help manage HBV-induced HCC by regulating survivin.