Mouse Model of Mutated in Colorectal Cancer Gene Deletion Reveals Novel Pathways in Inflammation and Cancer

© 2019 The Authors Background & Aims: The early events by which inflammation promotes cancer are still not fully defined. The MCC gene is silenced by promoter methylation in colitis-associated and sporadic colon tumors, but its functional significance in precancerous lesions or polyps is not known. Here, we aimed to determine the impact of Mcc deletion on the cellular pathways and carcinogenesis associated with inflammation in the mouse proximal colon. Methods: We generated knockout mice with deletion of Mcc in the colonic/intestinal epithelial cells (MccΔIEC) or in the whole body (MccΔ/Δ). Drug-induced lesions were analyzed by transcriptome profiling (at 10 weeks) and histopathology (at 20 weeks). Cell-cycle phases and DNA damage proteins were analyzed by flow cytometry and Western blot of hydrogen peroxide–treated mouse embryo fibroblasts. Results: Transcriptome profiling of the lesions showed a strong response to colon barrier destruction, such as up-regulation of key inflammation and cancer-associated genes as well as 28 interferon γ–induced guanosine triphosphatase genes, including the homologs of Crohn's disease susceptibility gene IRGM. These features were shared by both Mcc-expressing and Mcc-deficient mice and many of the altered gene expression pathways were similar to the mesenchymal colorectal cancer subtype known as consensus molecular subtype 4 (CMS4). However, Mcc deletion was required for increased carcinogenesis in the lesions, with adenocarcinoma in 59% of MccΔIEC compared with 19% of Mcc-expressing mice (P =.002). This was not accompanied by hyperactivation of β-catenin, but Mcc deletion caused down-regulation of DNA repair genes and a disruption of DNA damage signaling. Conclusions: Loss of Mcc may promote cancer through a failure to repair inflammation-induced DNA damage. We provide a comprehensive transcriptome data set of early colorectal lesions and evidence for the in vivo significance of MCC silencing in colorectal cancer

Proteogenomic analysis identifies a novel human SHANK3 Isoform

© 2015 by the authors; licensee MDPI, Basel, Switzerland. Mutations of the SHANK3 gene have been associated with autism spectrum disorder. Individuals harboring different SHANK3 mutations display considerable heterogeneity in their cognitive impairment, likely due to the high SHANK3 transcriptional diversity. In this study, we report a novel interaction between the Mutated in colorectal cancer (MCC) protein and a newly identified SHANK3 protein isoform in human colon cancer cells and mouse brain tissue. Hence, our proteogenomic analysis identifies a new human long isoform of the key synaptic protein SHANK3 that was not predicted by the human reference genome. Taken together, our findings describe a potential new role for MCC in neurons, a new human SHANK3 long isoform and, importantly, highlight the use of proteomic data towards the re-annotation of GC-rich genomic regions

JRK is a positive regulator of β-catenin transcriptional activity commonly overexpressed in colon, breast and ovarian cancer.

The loss of β-catenin inhibitory components is a well-established mechanism of carcinogenesis but β-catenin hyperactivity can also be enhanced through its coactivators. Here we first interrogated a highly validated genomic screen and the largest repository of cancer genomics data and identified JRK as a potential new oncogene and therapeutic target of the β-catenin pathway. We proceeded to validate the oncogenic role of JRK in colon cancer cells and primary tumors. Consistent with a β-catenin activator function, depletion of JRK in several cancer cell lines repressed β-catenin transcriptional activity and reduced cell proliferation. Importantly, JRK expression was aberrantly elevated in 21% of colorectal cancers, 15% of breast and ovarian cancers and was associated with increased expression of β-catenin target genes and increased cell proliferation. This study shows that JRK is required for β-catenin hyperactivity regardless of the adenomatous polyposis coli/β-catenin mutation status and targeting JRK presents new opportunities for therapeutic intervention in cancer

JRK is a positive regulator of β-catenin transcriptional activity commonly overexpressed in colon, breast and ovarian cancer

The loss of β-catenin inhibitory components is a well-established mechanism of carcinogenesis but β-catenin hyperactivity can also be enhanced through its coactivators. Here we first interrogated a highly validated genomic screen and the largest repository of cancer genomics data and identified JRK as a potential new oncogene and therapeutic target of the β-catenin pathway. We proceeded to validate the oncogenic role of JRK in colon cancer cells and primary tumors. Consistent with a β-catenin activator function, depletion of JRK in several cancer cell lines repressed β-catenin transcriptional activity and reduced cell proliferation. Importantly, JRK expression was aberrantly elevated in 21% of colorectal cancers, 15% of breast and ovarian cancers and was associated with increased expression of β-catenin target genes and increased cell proliferation. This study shows that JRK is required for β-catenin hyperactivity regardless of the adenomatous polyposis coli/β-catenin mutation status and targeting JRK presents new opportunities for therapeutic intervention in cancer

Virus-induced senescence is driver and therapeutic target in COVID-19

Derailed cytokine and immune cell networks account for organ damage and clinical severity of COVID-19. Here we show that SARS-CoV-2, like other viruses, evokes cellular senescence as a primary stress response in infected cells. Virus-induced senescence (VIS) is indistinguishable from other forms of cellular senescence and accompanied by a senescence-associated secretory phenotype (SASP), composed of pro-inflammatory cytokines, extracellular matrix-active factors and pro-coagulatory mediators. COVID-19 patients displayed markers of senescence in their airway mucosa in situ and elevated serum levels of SASP factors. Mirroring COVID-19 hallmark features such as macrophage and neutrophil infiltration, endothelial damage and widespread thrombosis in affected lung tissue in vitro assays demonstrated macrophage activation with SASP-reminiscent secretion, complement lysis and SASP-amplifying secondary senescence of endothelial cells, neutrophil extracellular trap (NET) formation as well as activation of platelets and the clotting cascade in response to supernatant of VIS cells, including SARS-CoV-2-induced senescence. Senolytics such as Navitoclax and Dasatinib/Quercetin selectively eliminated VIS cells, mitigated COVID-19-reminiscent lung disease and reduced inflammation in SARS-CoV-2-driven hamster and mouse models. Our findings mark VIS as pathogenic trigger of COVID-19-related cytokine escalation and organ damage, and suggest senolytic targeting of virus-infected cells as a novel treatment option against SARS-CoV-2 and perhaps other viral infections

‘MCC’ protein interacts with E-cadherin and β-catenin strengthening cell–cell adhesion of HCT116 colon cancer cells

E-cadherin and β-catenin are key proteins that are essential in the formation of the epithelial cell layer in the colon but their regulatory pathways that are disrupted in cancer metastasis are not completely understood. Mutated in colorectal cancer (MCC) is a tumour suppressor gene that is silenced by promoter methylation in colorectal cancer and particularly in patients with increased lymph node metastasis. Here, we show that MCC methylation is found in 45% of colon and 24% of rectal cancers and is associated with proximal colon, poorly differentiated, circumferential and mucinous tumours as well as increasing T stage and larger tumour size. Knockdown of MCC in HCT116 colon cancer cells caused a reduction in E-cadherin protein level, which is a hallmark of epithelial–mesenchymal transition in cancer, and consequently diminished the E-cadherin/β-catenin complex. MCC knockdown disrupted cell–cell adhesive strength and integrity in the dispase and transepithelial electrical resistance assays, enhanced hepatocyte growth factor-induced cell scatter and increased tumour cell invasiveness in an organotypic assay. The Src/Abl inhibitor dasatinib, a candidate anti-invasive drug, abrogated the invasive properties induced by MCC deficiency. Mechanistically, we establish that MCC interacts with the E-cadherin/β-catenin complex. These data provide a significant advance in the current understanding of cell–cell adhesion in colon cancer cells