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 uncovers 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.
SYNOPSIS
Resistance to therapy occurs in most liver cancer patients treated with Sorafenib, and patients succumb to the disease. A synthetic lethal screen identified a regulatory circuit, which prevents ferroptosis and promotes cancer cell survival, thus promoting resistance to Sorafenib.
The transcription factors YAP and TAZ stabilize ATF4 by promoting its nuclear import to cooperatively induce expression of SLC7A11, a cystine importer critical for glutathione synthesis.
Glutathione synthesis and homeostasis are required to repress ferroptosis and to maintain Sorafenib resistance in liver cancer cells.
Inhibition of Glutathione synthesis re‐sensitizes Sorafenib‐resistant cancer cells to Sorafenib therapy, which then induces ferroptosis and represses tumor growth in murine liver cancer models.
Pharmacological repression of the anti‐oxidant pathways regulated by YAP/TAZ and ATF4 could re‐sensitize therapy‐resistant liver cancers to Sorafenib treatment.
Resistance to therapy occurs in most liver cancer patients treated with Sorafenib, and patients succumb to the disease. A synthetic lethal screen identified a regulatory circuit, which prevents ferroptosis and promotes cancer cell survival, thus promoting resistance to Sorafenib.
Proteogenomic analyses of hepatocellular carcinomas (HCC) have focused on early-stage, HBV-associated HCCs. Here we present an integrated proteogenomic analysis of HCCs across clinical stages and ...etiologies. Pathways related to cell cycle, transcriptional and translational control, signaling transduction, and metabolism are dysregulated and differentially regulated on the genomic, transcriptomic, proteomic and phosphoproteomic levels. We describe candidate copy number-driven driver genes involved in epithelial-to-mesenchymal transition, the Wnt-β-catenin, AKT/mTOR and Notch pathways, cell cycle and DNA damage regulation. The targetable aurora kinase A and CDKs are upregulated. CTNNB1 and TP53 mutations are associated with altered protein phosphorylation related to actin filament organization and lipid metabolism, respectively. Integrative proteogenomic clusters show that HCC constitutes heterogeneous subgroups with distinct regulation of biological processes, metabolic reprogramming and kinase activation. Our study provides a comprehensive overview of the proteomic and phophoproteomic landscapes of HCCs, revealing the major pathways altered in the (phospho)proteome.
Abstract
Understanding the mechanisms underlying evasive resistance in cancer is an unmet medical need to improve the efficacy of current therapies. In hepatocellular carcinoma (HCC), aberrant ...expression of hypoxia-inducible factor 1 α (HIF1α) and increased aerobic glycolysis metabolism are drivers of resistance to therapy with the multi-kinase inhibitor Sorafenib. However, it has remained unknown how HIF1α is activated and how its activity and the subsequent induction of aerobic glycolysis promote Sorafenib resistance in HCC. Here, we report the ubiquitin-specific peptidase USP29 as a new regulator of HIF1α and of aerobic glycolysis during the development of Sorafenib resistance in HCC. In particular, we identified USP29 as a critical deubiquitylase (DUB) of HIF1α, which directly deubiquitylates and stabilizes HIF1α and, thus, promotes its transcriptional activity. Among the transcriptional targets of HIF1α is the gene encoding hexokinase 2 (HK2), a key enzyme of the glycolytic pathway. The absence of USP29, and thus of HIF1α transcriptional activity, reduces the levels of aerobic glycolysis and restores sensitivity to Sorafenib in Sorafenib-resistant HCC cells in vitro and in xenograft transplantation mouse models in vivo. Notably, the absence of USP29 and high HK2 expression levels correlate with the response of HCC patients to Sorafenib therapy. Together, the data demonstrate that, as a DUB of HIF1α, USP29 promotes Sorafenib resistance in HCC cells, in parts by upregulating glycolysis, thereby opening new avenues for therapeutically targeting Sorafenib-resistant HCC in patients.
Innate lymphoid cells (ILCs) have a protective immune function at mucosal tissues but can also contribute to immunopathology. Previous work has shown that the serine/threonine kinase mammalian target ...of rapamycin complex 1 (mTORC1) is involved in generating protective ILC3 cytokine responses during bacterial infection. However, whether mTORC1 also regulates IFN-γ-mediated immunopathology has not been investigated. In addition, the role of mTORC2 in ILC3s is unknown. Using mice specifically defective for either mTORC1 or mTORC2 in ILC3s, we show that both mTOR complexes regulate the maintenance of ILC3s at steady state and pathological immune response during colitis. mTORC1 and to a lesser extend mTORC2 promote the proliferation of ILC3s in the small intestine. Upon activation, intestinal ILC3s produce less IFN-γ in the absence of mTOR signaling. During colitis, loss of both mTOR complexes in colonic ILC3s results in the reduced production of inflammatory mediators, recruitment of neutrophils and immunopathology. Similarly, treatment with rapamycin after colitis induction ameliorates the disease. Collectively, our data show a critical role for both mTOR complexes in controlling ILC3 cell numbers and ILC3-driven inflammation in the intestine.
Abstract
The treatment of colorectal cancer (CRC) is an unmet medical need in absence of early diagnosis. Here, upon characterizing cancer-specific transposable element-driven transpochimeric gene ...transcripts (TcGTs) produced by this tumor in the SYSCOL cohort, we find that expression of the hominid-restricted retrogene
POU5F1B
through aberrant activation of a primate-specific endogenous retroviral promoter is a strong negative prognostic biomarker. Correlating this observation, we demonstrate that POU5F1B fosters the proliferation and metastatic potential of CRC cells. We further determine that POU5F1B, in spite of its phylogenetic relationship with the POU5F1/OCT4 transcription factor, is a membrane-enriched protein that associates with protein kinases and known targets or interactors as well as with cytoskeleton-related molecules, and induces intracellular signaling events and the release of
trans
-acting factors involved in cell growth and cell adhesion. As
POU5F1B
is an apparently non-essential gene only lowly expressed in normal tissues, and as
POU5F1B
-containing TcGTs are detected in other tumors besides CRC, our data provide interesting leads for the development of cancer therapies.
Fibroblast activation protein α (FAP) plays an important role in tissue remodeling and helps tumor cells invade surrounding tissue. We sought to investigate FAP as a prognostic molecular marker in ...colorectal cancer (CRC) using immunohistochemical and transcriptomic data.
expression and clinicopathological information were obtained from The Cancer Genome Atlas data set. The association of
expression and tissue cellular heterogeneity landscape was explored using the xCell method. We evaluated FAP protein expression in a cohort of 92 CRCs and 19 non-tumoral tissues. We observed that
was upregulated in tumors both at the mRNA and protein levels, and its expression was associated with advanced stages, poor survival, and consensus molecular subtype 4.
expression was also associated with angiogenesis and collagen degradation. We observed an enrichment in immune-cell process-related genes associated with
overexpression. Colorectal cancers with high
expression display an inflamed phenotype enriched for macrophages and monocytes. Those tumors showed enrichment for regulatory T cell populations and depletion of T
1 and natural killer T cells, pointing to an immunosuppressive environment. Colorectal cancers with high levels of stromal FAP are associated with aggressive disease progression and survival. Our results suggest that FAP plays additional roles in tumor progression such as modulation of angiogenesis and immunoregulation in the tumor microenvironment.
Pygopus 2 (Pygo2) is a coactivator of Wnt/β-catenin signaling that can bind bi- or trimethylated lysine 4 of histone-3 (H3K4me
) and participate in chromatin reading and writing. It remains unknown ...whether the Pygo2-H3K4me
association has a functional relevance in breast cancer progression
. To investigate the functional relevance of histone-binding activity of Pygo2 in malignant progression of breast cancer, we generated a knock-in mouse model where binding of Pygo2 to H3K4me
was rendered ineffective. Loss of Pygo2-histone interaction resulted in smaller, differentiated, and less metastatic tumors, due, in part, to decreased canonical Wnt/β-catenin signaling. RNA- and ATAC-sequencing analyses of tumor-derived cell lines revealed downregulation of TGFβ signaling and upregulation of differentiation pathways such as PDGFR signaling. Increased differentiation correlated with a luminal cell fate that could be reversed by inhibition of PDGFR activity. Mechanistically, the Pygo2-histone interaction potentiated Wnt/β-catenin signaling, in part, by repressing the expression of Wnt signaling antagonists. Furthermore, Pygo2 and β-catenin regulated the expression of miR-29 family members, which, in turn, repressed PDGFR expression to promote dedifferentiation of wild-type Pygo2 mammary epithelial tumor cells. Collectively, these results demonstrate that the histone binding function of Pygo2 is important for driving dedifferentiation and malignancy of breast tumors, and loss of this binding activates various differentiation pathways that attenuate primary tumor growth and metastasis formation. Interfering with the Pygo2-H3K4me
interaction may therefore serve as an attractive therapeutic target for metastatic breast cancer. SIGNIFICANCE: Pygo2 represents a potential therapeutic target in metastatic breast cancer, as its histone-binding capability promotes β-catenin-mediated Wnt signaling and transcriptional control in breast cancer cell dedifferentiation, EMT, and metastasis.
Aim
To determine the programmed death ligand‐1 (PD‐L1) expression rates in sarcomatoid lung carcinomas and to compare clinicopathologic features and survival rates of PD‐L1‐positive and negative ...patients.
Methods
PD‐L1 expression was evaluated in 65 surgically resected sarcomatoid carcinomas. The clinicopathologic features of cases with PD‐L1‐positive and negative tumors were compared. Kaplan–Meier survival analysis was performed. Multiple Cox proportional hazard regression analysis was performed to determine independent predictors of overall survival.
Results
PD‐L1 antibody positivity was found in 72.3% of surgically resected sarcomatoid lung carcinomas. Regarding histopathologic subtypes, PD‐L1 expression was positive in 80.4% of pleomorphic carcinomas, 62.5% of spindle‐ and/or giant‐cell carcinomas, and 16.7% of carcinosarcomas. Pleural invasion was observed in 68.1% of PD‐L1‐positive cases and 27.8% of PD‐L1‐negative cases (P = 0.008). No difference in survival was found between PD‐L1‐positive and ‐negative tumors. The only factor significantly associated with poor survival was the pathological stage of the tumor.
Conclusions
This study reveals a high rate of PD‐L1 positivity in a large number of sarcomatoid lung carcinoma cases with pleomorphic carcinoma, spindle‐ and/or giant‐cell carcinoma, and carcinosarcoma subtypes. The only significantly different clinicopathologic feature in PD‐L1‐positive cases is pleural invasion. PD‐L1 positivity is not a significant predictor of survival in sarcomatoid lung carcinomas.
Sarcomatoid carcinomas are extremely rare lung tumors with survival rates and prognoses significantly worse than other non‐small‐cell carcinoma types. Treatments targeting the PD1/PD‐L1 pathway have recently emerged as a promising therapeutic approach for sarcomatoid lung carcinomas. This study investigated PD‐L1 expression and clinicopathologic features of surgically resected sarcomatoid lung carcinomas.
Colorectal cancer (CRC) is a leading cause of cancer-associated death. In the tumor site, the interplay between effector immune cells and cancer cells determines the balance between tumor elimination ...or outgrowth. We discovered that the protein TMEM123 is over-expressed in tumour-infiltrating CD4 and CD8 T lymphocytes and it contributes to their effector phenotype. The presence of infiltrating TMEM123+ CD8+ T cells is associated with better overall and metastasis-free survival. TMEM123 localizes in the protrusions of infiltrating T cells, it contributes to lymphocyte migration and cytoskeleton organization. TMEM123 silencing modulates the underlying signaling pathways dependent on the cytoskeletal regulator WASP and the Arp2/3 actin nucleation complex, which are required for synaptic force exertion. Using tumoroid-lymphocyte co-culture assays, we found that lymphocytes form clusters through TMEM123, anchoring to cancer cells and contributing to their killing. We propose an active role for TMEM123 in the anti-cancer activity of T cells within tumour microenvironment.
PDF
