Project description:FAM83A (family with sequence similarity 83, member A) has been found to be highly expressed in cancers. The purpose of this study was to clarify the role and mechanism of FAM83A in lung cancers. The expression of FAM83A in lung cancer cells was enhanced by gene transfection or knocked down by small interfering RNA interference. The key proteins of the Wnt signaling pathway, the Hippo signaling pathway, and epithelial-mesenchymal transition (EMT) were examined using Western blot. The proliferation and invasion of lung cancer cells were examined using cell proliferation, colony formation, and invasion assays. The expression of FAM83A in lung cancer tissues was significantly increased and was correlated with advanced tumor-node-metastasis (TNM) stage and poor prognosis. Overexpression of FAM83A enhanced the proliferation, colony formation, and invasion of lung cancer cells. Meanwhile, FAM83A overexpression increased the expression of active β-catenin and Wnt target genes and the activity of EMT. Furthermore, in FAM83A-overexpressed cells, the activity of Hippo pathway was downregulated, whereas the expression of yes-associated protein (YAP) and its downstream targets cyclin E and CTGF were upregulated. The inhibitor of the Wnt signaling pathway, XAV-939, reversed the promoting effect of FAM83A on YAP, cyclin E, and CTGF. On knocking down the expression of FAM83A, we obtained the opposite results. However, the inhibitor of GSK3β, CHIR-99021, restored the expression of YAP, cyclin E, and CTGF after FAM83A was knocked down. FAM83A is highly expressed in lung cancers and correlated with advanced TNM stage and poor prognosis. FAM83A promotes the proliferation and invasion of lung cancer cells by regulating the Wnt and Hippo signaling pathways and EMT process.
Project description:Since the initial discovery of the oncogenic activity of WNT ligands our understanding of the complex roles for WNT signaling pathways in lung cancers has increased substantially. In the current review, the various effects of activation and inhibition of the WNT signaling pathways are summarized in the context of lung carcinogenesis. Recent evidence regarding WNT ligand transport mechanisms, the role of WNT signaling in lung cancer angiogenesis and drug transporter regulation and the importance of microRNA and posttranscriptional regulation of WNT signaling are also reviewed.
Project description:Malignant tumors develop through multiple steps of initiation and progression, and tumor initiation is of singular importance in tumor prevention, diagnosis, and treatment. However, the molecular mechanism whereby a signaling network of interacting pathways restrains proliferation in normal cells and prevents tumor initiation is still poorly understood. Here, we have reported that the Hippo, Wnt/?-catenin, and Notch pathways form an interacting network to maintain liver size and suppress hepatocellular carcinoma (HCC). Ablation of the mammalian Hippo kinases Mst1 and Mst2 in liver led to rapid HCC formation and activated Yes-associated protein/WW domain containing transcription regulator 1 (YAP/TAZ), STAT3, Wnt/?-catenin, and Notch signaling. Previous work has shown that abnormal activation of these downstream pathways can lead to HCC. Rigorous genetic experiments revealed that Notch signaling forms a positive feedback loop with the Hippo signaling effector YAP/TAZ to promote severe hepatomegaly and rapid HCC initiation and progression. Surprisingly, we found that Wnt/?-catenin signaling activation suppressed HCC formation by inhibiting the positive feedback loop between YAP/TAZ and Notch signaling. Furthermore, we found that STAT3 in hepatocytes is dispensable for HCC formation when mammalian sterile 20-like kinase 1 and 2 (Mst1 and Mst2) were removed. The molecular network we have identified provides insights into HCC molecular classifications and therapeutic developments for the treatment of liver tumors caused by distinct genetic mutations.
Project description:Metastatic lung cancer is incurable and a leading cause of cancer death in the United States. However, the molecular mechanism by which lung cancer cells invade other tissues has remained unclear. We previously identified fibulin-5, an extracellular matrix protein, as a frequently silenced gene in lung cancer and a suppressor of cell invasion. In this study, we found fibulin-5 functions by inhibiting the Wnt/?-catenin pathway. The Cancer Genome Atlas (TCGA) datasets show a strong association between loss of fibulin-5 expression and poor outcomes of lung cancer patients, and also activation of the Wnt target genes MMP-7 and c-Myc. Fibulin-5 impedes Wnt/?-catenin signaling by inhibiting extracellular signal-regulated kinase (ERK) to activate glycogen synthase kinase-3 ? (GSK3?), which downregulates ?-catenin and prevents its nuclear accumulation, leading to suppression of MMP-7 and c-Myc expression. These effects of fibulin-5 are mediated by its amino-terminal integrin-binding RGD motif. Fibulin-5 also blocks Wnt/?-catenin signaling in vivo in H460 metastasis and H1299 tumor models. Furthermore, knockdown of ?-catenin suppresses metastasis of H460 tumors, while knockdown of GSK3? promotes metastasis of fibulin-5-expressing H1752 tumors. Together, our results suggest that fibulin-5 functions as a metastasis suppressor in lung cancer by modulating tumor microenvironment to suppress Wnt/?-catenin signaling.
Project description:BackgroundThough we recently reported that the WWC3 inhibits the invasiveness and metastasis of lung cancer by activating the Hippo pathway, the impact and underlying mechanisms of this process still remain unclear.MethodsTo identify the role of WWC3 in epithelial-mesenchymal transition of lung cancer, we performed immunohistochemistry to detect the expression levels of WWC3 and EMT-related biomarker, and analyzed their correlations in a cohort of 127 patients with NSCLC. Wound healing assay and cell invasion assay were applied to explore cell invasive ability change after WWC3 knockdown. qRT-PCR and immunoblotting were performed to assess mRNA and protein levels of EMT-related biomarkers and the main molecules changes of Hippo signaling caused by WWC3. Immunoprecipition was to examine WWC3 and LATS1 interaction.ResultsWWC3 knockdown drives a pronounced shift from the epithelial to the mesenchymal phenotype in lung cancer cells. In addition, WWC3 ectopic expression in lung cancer cells attenuates mesenchymal markers and increases the epithelial markers expressions; however, WWC3-ΔWW plasmid abrogated these effects. WWC3 silencing by shRNA exerts the opposite effect. Furthermore, WWC3 levels were inversely correlated with the levels of EMT inducers (Snail and Slug) in lung cancer cells and specimens. Immunoblotting revealed that WWC3 wild-type upregulates large tumor suppressor (LATS1) and yes-associated protein (YAP) phosphorylation through its WW domain, hence activating Hippo pathway. Knockdown of YAP and LATS1, as well as the as the Verteporfin (VP) usage, could reverse this effect caused by WWC3 silencing.ConclusionThese findings suggest that WWC3 works as a tumor suppressor to inhibit EMT process and confer its candidacy as a potential therapeutic target in lung cancer.
Project description:Cancer stem-like cells (CSLCs) acquire enhanced immune checkpoint responses to evade immune cell killing and promote tumor progression. Here we showed that signal regulatory protein γ (SIRPγ) determined CSLC properties and immune evasiveness in a small population of lung adenocarcinoma (LUAD) cancer cells. A SIRPγhi population displayed CSLC properties and transmitted the immune escape signal through sustaining CD47 expression in both SIRPγhi and SIRPγlo/- tumor cells. SIRPγ bridged MST1 and PP2A to facilitate MST1 dephosphorylation, resulting in Hippo/YAP activation and leading to cytokine release by CSLCs, which stimulated CD47 expression in LUAD cells and consequently inhibited tumor cell phagocytosis. SIRPγ promoted tumor growth and metastasis in vivo through YAP signaling. Notably, SIRPγ targeting with genetic SIRPγ knockdown or a SIRPγ-neutralizing antibody inhibited CSLC phenotypes and elicited phagocytosis that suppressed tumor growth in vivo. SIRPG was upregulated in human LUAD and its overexpression predicted poor survival outcome. Thus, SIRPγhi cells serve as CSLCs and tumor immune checkpoint-initiating cells, propagating the immune escape signal to the entire cancer cell population. Our study identifies Hippo/YAP signaling as the first mechanism by which SIRPγ is engaged and reveals that targeting SIRPγ represents an immune- and CSLC-targeting strategy for lung cancer therapy.
Project description:The 5 year survival rate of lung cancer is <20%, with most patients dying from distant metastasis. However, the molecular mechanisms underlying lung cancer invasion and metastasis have not been fully characterized. In this study, we found that fibulin-3, a fibulin family extracellular matrix protein, functions as a suppressor of lung cancer invasion and metastasis. Fibulin-3 was downregulated in large fractions of lung tumors and cell lines, and inhibited lung cancer cell invasion and the expression of matrix metalloproteinase-7 (MMP-7), a promoter of lung cancer invasion. The expression levels of fibulin-3 and MMP-7 were inversely correlated in lung tumors. Fibulin-3 inhibited extracellular signal-regulated kinase (ERK) to activate glycogen synthase kinase 3? and suppress Wnt/?-catenin signaling, which induces MMP-7 expression in lung cancer cells. Furthermore, fibulin-3 expression impeded the growth and metastasis of lung tumors in mice. Collectively, these results suggest that downregulation of fibulin-3 contributes to lung cancer invasion and metastasis by activating Wnt/?-catenin signaling and MMP-7 expression.
Project description:Wingless-type protein (Wnt)/β-catenin pathway alterations in non-small cell lung cancer (NSCLC) are associated with poor prognosis and resistance. In 598 stage III-IV NSCLC patients receiving platinum-based chemotherapy at the MD Anderson Cancer Center (MDACC), we correlated survival with 441 host single-nucleotide polymorphisms (SNPs) in 50 Wnt pathway genes. We then assessed the most significant SNPs in 240 Mayo Clinic patients receiving platinum-based chemotherapy for advanced NSCLC, 127 MDACC patients receiving platinum-based adjuvant chemotherapy and 340 early stage MDACC patients undergoing surgery alone (cohorts 2-4). In multivariate analysis, survival correlates with SNPs for AXIN2 (rs11868547 and rs4541111, of which rs11868547 was assessed in cohorts 2-4), Wnt-5B (rs12819505), CXXC4 (rs4413407) and WIF-1 (rs10878232). Median survival was 19.7, 15.6 and 10.7 months for patients with 1, 2 and 3-5 unfavorable genotypes, respectively (P=3.8 × 10(-9)). Survival tree analysis classified patients into two groups (median survival time 11.3 vs 17.3 months, P=4.7 × 10(-8)). None of the SNPs achieved significance in cohorts 2-4; however, there was a trend in the same direction as cohort 1 for 3 of the SNPs. Using online databases, we found rs10878232 displayed expression quantitative trait loci correlation with the expression of LEMD3, a neighboring gene previously associated with NSCLC survival. In conclusion, results from cohort 1 provide further evidence for an important role for Wnt in NSCLC. Investigation of Wnt inhibitors in advanced NSCLC would be reasonable. Lack of an SNP association with outcome in cohorts 2-4 could be due to low statistical power, impact of patient heterogeneity or false-positive observations in cohort 1.
Project description:Genetic regulation of mammalian heart size is poorly understood. Hippo signaling represents an organ-size control pathway in Drosophila, where it also inhibits cell proliferation and promotes apoptosis in imaginal discs. To determine whether Hippo signaling controls mammalian heart size, we inactivated Hippo pathway components in the developing mouse heart. Hippo-deficient embryos had overgrown hearts with elevated cardiomyocyte proliferation. Gene expression profiling and chromatin immunoprecipitation revealed that Hippo signaling negatively regulates a subset of Wnt target genes. Genetic interaction studies indicated that ?-catenin heterozygosity suppressed the Hippo cardiomyocyte overgrowth phenotype. Furthermore, the Hippo effector Yap interacts with ?-catenin on Sox2 and Snai2 genes. These data uncover a nuclear interaction between Hippo and Wnt signaling that restricts cardiomyocyte proliferation and controls heart size.
Project description:Nitidine chloride (NC) has significant anti-tumor properties; however, the precise mechanism related to NC still needs further investigation. This study intends to investigate the anti-tumor functions and the feasible molecular basis of NC in NSCLC cells. Therefore, we determined the mechanism of NC-mediated anti-tumor function through various methods. Cell proliferation ability and migration and invasion were detected by CCK-8, colony formation assay and Transwell assay, respectively. Furthermore, flow cytometry was used to detect apoptosis, cell cycle and ROS. Moreover, protein expression level was measured by western blot. Our results showed that NC can inhibit the growth, motility of NSCLC cells, induce apoptosis and arrest cell cycle. Meanwhile, NC increased the level of ROS in NSCLC cells. Moreover, western blot data showed that NC suppressed the expression of Lats1, Mob1, and YAP, and enhanced the expression of p-Lats1, p-Mob1, p-YAP1 (ser127). Overall, our research reveals that NC exerts anticancer activity by activating and modulating the Hippo signaling pathway.