Yes tyrosine kinase signaling promotes liver cancer development [DSP294_SNU449]
Ontology highlight
ABSTRACT: Hepatocellular carcinoma (HCC) is a disease with high unmet medical need. Most patients are diagnosed at late stage with few therapeutic options and a dismal prognosis. While molecular genomic studies have been helpful in improving the understanding and treatment of many types of cancer, their impact on HCC has been negligible so far. This is largely due to a poor understanding of the underlying mechanisms of this cancer and the lack of dominant oncogene that can be targeted pharmacologically. Here we report the identification of a novel Yes oncogenic signaling pathway in HCC that has escaped large-scale molecular genetic studies. Using a combination of genetic and pharmacological interventions in cellular and mouse models of HCC, we show that Yes activity is necessary for HCC cell proliferation. Transgenic expression of activated Yes in mouse hepatocytes is sufficient to induce liver tumorigenesis. Mechanistically, we found that Yes directly phosphorylates YAP and TAZ, promoting their nuclear accumulation and transcriptional activity in HCC cells and liver tumors, and that YAP/TAZ are effectors of Yes oncogenic transformation. Src-family kinase activation correlates with YAP tyrosine phosphorylation and nuclear localization in human HCC, and is associated with increased tumor burden. Specifically, high Yes activity predicts significantly shorter overall survival in HCC patients. Our findings identify Yes as a potential therapeutic target in HCC.
Project description:Hepatocellular carcinoma (HCC) is a disease with high unmet medical need. Most patients are diagnosed at late stage with few therapeutic options and a dismal prognosis. While molecular genomic studies have been helpful in improving the understanding and treatment of many types of cancer, their impact on HCC has been negligible so far. This is largely due to a poor understanding of the underlying mechanisms of this cancer and the lack of dominant oncogene that can be targeted pharmacologically. Here we report the identification of a novel Yes oncogenic signaling pathway in HCC that has escaped large-scale molecular genetic studies. Using a combination of genetic and pharmacological interventions in cellular and mouse models of HCC, we show that Yes activity is necessary for HCC cell proliferation. Transgenic expression of activated Yes in mouse hepatocytes is sufficient to induce liver tumorigenesis. Mechanistically, we found that Yes directly phosphorylates YAP and TAZ, promoting their nuclear accumulation and transcriptional activity in HCC cells and liver tumors, and that YAP/TAZ are effectors of Yes oncogenic transformation. Src-family kinase activation correlates with YAP tyrosine phosphorylation and nuclear localization in human HCC, and is associated with increased tumor burden. Specifically, high Yes activity predicts significantly shorter overall survival in HCC patients. Our findings identify Yes as a potential therapeutic target in HCC.
Project description:Hepatocellular carcinoma (HCC) is a disease with high unmet medical need. Most patients are diagnosed at late stage with few therapeutic options and a dismal prognosis. While molecular genomic studies have been helpful in improving the understanding and treatment of many types of cancer, their impact on HCC has been negligible so far. This is largely due to a poor understanding of the underlying mechanisms of this cancer and the lack of dominant oncogene that can be targeted pharmacologically. Here we report the identification of a novel Yes oncogenic signaling pathway in HCC that has escaped large-scale molecular genetic studies. Using a combination of genetic and pharmacological interventions in cellular and mouse models of HCC, we show that Yes activity is necessary for HCC cell proliferation. Transgenic expression of activated Yes in mouse hepatocytes is sufficient to induce liver tumorigenesis. Mechanistically, we found that Yes directly phosphorylates YAP and TAZ, promoting their nuclear accumulation and transcriptional activity in HCC cells and liver tumors, and that YAP/TAZ are effectors of Yes oncogenic transformation. Src-family kinase activation correlates with YAP tyrosine phosphorylation and nuclear localization in human HCC, and is associated with increased tumor burden. Specifically, high Yes activity predicts significantly shorter overall survival in HCC patients. Our findings identify Yes as a potential therapeutic target in HCC.
Project description:Hepatocellular carcinoma (HCC) is a disease with high unmet medical need. Most patients are diagnosed at late stage with few therapeutic options and a dismal prognosis. While molecular genomic studies have been helpful in improving the understanding and treatment of many types of cancer, their impact on HCC has been negligible so far. This is largely due to a poor understanding of the underlying mechanisms of this cancer and the lack of dominant oncogene that can be targeted pharmacologically. Here we report the identification of a novel Yes oncogenic signaling pathway in HCC that has escaped large-scale molecular genetic studies. Using a combination of genetic and pharmacological interventions in cellular and mouse models of HCC, we show that Yes activity is necessary for HCC cell proliferation. Transgenic expression of activated Yes in mouse hepatocytes is sufficient to induce liver tumorigenesis. Mechanistically, we found that Yes directly phosphorylates YAP and TAZ, promoting their nuclear accumulation and transcriptional activity in HCC cells and liver tumors, and that YAP/TAZ are effectors of Yes oncogenic transformation. Src-family kinase activation correlates with YAP tyrosine phosphorylation and nuclear localization in human HCC, and is associated with increased tumor burden. Specifically, high Yes activity predicts significantly shorter overall survival in HCC patients. Our findings identify Yes as a potential therapeutic target in HCC.
Project description:Hepatocellular carcinoma (HCC) presents a major health issue due to its rising incidence and limited therapeutic options. The Hippo pathway transducers yes-associated protein (YAP) and WW-domain containing transcription regulator 1 (WWTR1/TAZ) are key regulators of liver tu-morigenesis promoting tumor formation and progression. Although first inhibitors are in clinical trials, targeting the upstream activation of YAP/TAZ could prove equally beneficial. To identify regulators of YAP/TAZ activity, we carried out a proximity labelling approach (BioID) coupled to mass-spectrometry. We verified CRKL as a new YAP-exclusive interaction partner, which is overexpressed in HCC patients correlating with YAP expression and activity as well as poor survival prognosis. In vitro experiments demonstrated CRKL dependent cell survival and loss of YAP binding induced through actin disruption. Moreover, we delineated an activation of the JNK/JUN pathway by CRKL, which promoted YAP transcription. Our data thus illustrated that CRKL not only promoted YAP activity through its binding but also through the induction of YAP transcription by JNK/JUN activation. This highlights the JNK/JUN pathway as a possible target to abrogate YAP expression in HCC patients.
Project description:The oncogenes yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are potent liver oncogenes. Because gene mutations cannot fully explain their nuclear enrichment, we aim to understand which mechanisms cause YAP/TAZ activation in liver cancer cells. The combination of proteomics and functional screening identified numerous apical cell polarity complex proteins interacting with both proteins. Co-immunoprecipitation (Co-IP) ex-periments confirmed that MPP5 (synonym: PALS1) physically interacts with YAP and TAZ. After removing different MPP5 protein domains, Co-IP analyses revealed that the PDZ domain plays a crucial role in YAP binding. The interaction between YAP and MPP5 in the cytoplasm of cancer cells was demonstrated by proximity ligation assays (PLAs). In human hepatocellular carcinoma (HCC) tissues, a reduction of apical MPP5 expression was observed, positively correlating with the nuclear accumulation of YAP and TAZ. Expression data analysis illustrated that MPP5 is in-versely associated with YAP/TAZ target gene signatures in human HCCs. Low MPP5 levels de-fine an HCC patient group with poor clinical outcome. In summary, MPP5 facilitates the nuclear exclusion of YAP and TAZ in HCC cells. This qualifies MPP5 as a tumor-suppressor gene and ex-plains how changes in cell polarity can foster tumorigenesis. .
Project description:The Hippo pathway effectors yes-associated protein (YAP) and WW domain containing transcription regulator 1 (TAZ/WWTR1) support tumor initiation and progression in various cancer entities including hepatocellular carcinoma (HCC). However, to which extent YAP and TAZ contribute to liver tumorigenesis via common and exclusive molecular mechanisms is poorly understood. RNAinterference (RNAi) experiments illustrate that YAP and TAZ individually support HCC cell viability and migration, while for invasion additive effects were observed. Comprehensive expression profiling revealed partly overlapping YAP/TAZ target genes as well as exclusively regulated genes.
Project description:Background & Aims: Succinate dehydrogenase enzyme (SDH) is frequently found to be diminished in Hepatocellular carcinoma (HCC) patient samples, and SDH reduction is associated with elevated succinate level and poor prognosis in HCC patients. But the underlying mechanisms about how impaired SDH activity promotes HCC malignancy remain unclear. Approach & Results: In this study, we observed remarkable downregulations of SDH subunits A and B (SDHA/B) in chronic liver injury-induced murine HCC models and HCC patient samples. Subsequent RNA sequencing, hematoxylin & eosin (H&E) staining and immunohistochemistry (IHC) analyses of HCC samples revealed that Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) were significantly upregulated in HCC, with their levels inversely correlating with that of SDHA/B. The protein stability of YAP/TAZ was greatly enhanced in SDHA/B-depleted HCC cells along with accumulation of succinate. Further mechanistic analyses demonstrated that impaired activity of SDHA/B resulted in succinate accumulation which facilitated the removal of NEDDylation on cullin1, therefore disrupted the E3 ubiquitin ligase SCFβ-TrCP complex, consequently led to YAP/TAZ stabilization and activation in HCC cells. The accelerated in vitro cell proliferation and in vivo tumor growth caused by SDHA/B reduction or succinate exposure were largely dependent on the aberrant activation of YAP/TAZ. Conclusions: Our study demonstrated that SDHA/B reduction promotes HCC proliferation by preventing the proteasomal degradation of YAP/TAZ through modulating cullin1 NEDDylation, thus addicts SDH-deficient HCC cells to YAP/TAZ pathway and renders these cells vulnerable to YAP/TAZ inhibition. Our findings warrant further investigation on the therapeutic effects of targeting YAP/TAZ in HCC patients displaying reduced SDHA/B or elevated succinate levels.
Project description:siRNA-mediated inhibition compared to untreated cells and cells transfected with nonsense siRNA. Loss of contact inhibition and anchorage-independent growth are hallmarks of cancer cells. In this context, frequent inactivation of the Hippo pathway and subsequent nuclear enrichment of the transcriptional coactivator yes-associated protein (YAP) uncouple cell proliferation and anti-apoptosis from contact inhibition, associated with uncontrolled tumor growth and tumor cell dissemination. However, general molecular mechanisms of tumor-supporting YAP activity remain unclear. In this study, we show that overexpression and nuclear accumulation of YAP in hepatocytes and hepatocellular carcinoma (HCC) cells leads to an induction of the Notch pathways through transcriptional activation of the Notch ligand jagged-1 (Jag-1). This induction of Jag-1 strictly depends on binding of YAP to TEAD4 and does not rely on WNT/β-catenin pathway activity. Co-activation of YAP, TEAD4, Jag-1, and the Notch target gene Hes-1 was significantly higher in HCC from patients with poor prognosis. High-level expression and nuclear accumulation of YAP correlates with Jag-1/Notch activation not only in human HCC tissues, but also in colon and pancreatic cancer tissues. Thus, our data demonstrate that YAP-driven co-activation of the Jag-1/Notch pathway in part facilitates oncogenic properties of the oncogene YAP not only in HCC but also in different gastrointestinal malignancies. Expression profiling of untreated HCC cell lines (control 1), cells transfected with scrambled/nonsense siRNA (control 2), and after siRNA-mediated YAP inhibition.
Project description:Hepatocellular carcinoma (HCC) is a disease of high unmet medical need that has become a global health problem. The development of targeted therapies for HCC has been hindered by the incomplete understanding of HCC pathogenesis and the limited number of relevant preclinical animal models. We have recently unveiled a novel YES-dependent oncogenic signaling pathway in HCC. To model this subset of HCC, we have established a series of syngeneic cell lines from liver tumors of transgenic mice expressing activated YES. The resulting HepYF cell lines were enriched for expression of stem cell/progenitor markers, proliferated rapidly and were characterized by high SRC-family kinase activity and activated mitogenic signaling pathways. Transcriptomic analysis indicated that HepYF cells are representative of the most aggressive proliferation class G3 subgroup of HCC. HepYF cells formed rapidly growing metastatic tumors upon orthotopic implantation into syngeneic hosts.
Project description:Understanding the mechanisms underlying evasive resistance in cancer is an unmet medical need to improve the efficacy of current therapies. In this study, a combination of shRNA-mediated synthetic lethality screening and transcriptomic analysis revealed the transcription factors YAP/TAZ as key drivers of Sorafenib resistance in hepatocellular carcinoma (HCC) by repressing Sorafenib-induced ferroptosis. Mechanistically, in a TEAD-dependent manner YAP/TAZ induce the expression of SLC7A11, a key transporter maintaining intracellular glutathione homeostasis, thus enabling HCC cells to overcome Sorafenib-induced ferroptosis. At the same time, YAP/TAZ sustain the protein stability, nuclear localization and transcriptional activity of ATF4 which in turn cooperates to induce SLC7A11 expression. Our study uncovered a critical role of YAP/TAZ in the repression of ferroptosis and thus in the establishment of Sorafenib resistance in HCC, highlighting YAP/TAZ-based rewiring strategies as potential approaches to overcome HCC therapy resistance.