Competing Engagement of ß-arrestin Isoforms Balances IGF1R/p53 Signaling and Controls Melanoma Cell Chemotherapeutic Responsiveness.

Constraints on the p53 tumor suppressor pathway have long been associated with the progression, therapeutic resistance, and poor prognosis of melanoma, the most aggressive form of skin cancer. Likewise, the insulin-like growth factor type 1 receptor (IGF1R) is recognized as an essential coordinator of transformation, proliferation, survival, and migration of melanoma cells. Given that ß-arrestin (ß-arr) system critically governs the anti/pro-tumorigenic p53/IGF1R signaling pathways through their common E3 ubiquitin-protein ligase MDM2, we explore whether unbalancing this system downstream of IGF1R can enhance the response of melanoma cells to chemotherapy. Altering ß-arr expression demonstrated that both ß-arr1-silencing and ß-arr2-overexpression (-ß-arr1/+ß-arr2) facilitated nuclear-to-cytosolic MDM2 translocation accompanied by decreased IGF1R expression, while increasing p53 levels, resulting in reduced cell proliferation/survival. Imbalance towards ß-arr2 (-ß-arr1/+ß-arr2) synergizes with the chemotherapeutic agent, dacarbazine, in promoting melanoma cell toxicity. In both 3D spheroid models and in vivo in zebrafish models, this combination strategy, through dual IGF1R downregulation/p53 activation, limits melanoma cell growth, survival and metastatic spread. In clinical settings, analysis of the TCGA-SKCM patient cohort confirms ß-arr1-/ß-arr2+ imbalance as a metastatic melanoma vulnerability that may enhance therapeutic benefit. Our findings suggest that under steady-state conditions, IGF1R/p53-tumor promotion/suppression status-quo is preserved by ß-arr1/2 homeostasis. Biasing this balance towards ß-arr2 can limit the protumorigenic IGF1R activities while enhancing p53 activity, thus reducing multiple cancer-sustaining mechanisms. Combined with other therapeutics, this strategy improves patient responses and outcomes to therapies relying on p53 or IGF1R pathways. IMPLICATIONS: Altogether, ß-arrestin system bias downstream IGF1R is an important metastatic melanoma vulnerability that may be conductive for therapeutic benefit.

DSC2 suppresses the growth of gastric cancer through the inhibition of nuclear translocation of γ-catenin and PTEN/PI3K/AKT signaling pathway.

BACKGROUND: Globally, gastric cancer (GC) is still a major leading cause of cancer-associated deaths. Downregulated desmocollin2 (DSC2) is considered to be closely related to tumor progression. However, the underlying mechanisms of DSC2 in GC progression require further exploration. METHOD: We initially constructed different GC cells based on DSC2 contents, established the mouse tumor xenografts, and subsequently performed clonal formation, MTT, Caspase-3 activity, and sperm DNA fragmentation assays to detect the functions of DSC2 in GC growth. Subsequently, we performed western blot, Co-IP, and immunofluorescence assays to investigate the underlying mechanisms through pretreatment with PI3K inhibitor, LY294002, and its activator, recombinant human insulin-like growth factor I (IGF1). RESULT: DSC2 could significantly inhibit the viability of GC cells at both in vitro and in vivo levels. The underlying mechanism may be that DSC2 binds the γ-catenin to decrease its nuclear level, thereby downregulating the anti-apoptotic factor BCL-2 expression and upregulating the pro-apoptotic factor P53 expression, which adjusts the PTEN/PI3K/AKT signaling pathway to promote the cancer cell apoptosis. CONCLUSIONS: Our finding suggests that DSC2 might be a potential therapeutic target for the treatment of cancers, most especially GC.

Prognostic Profiling of the EMT-Associated and Immunity-Related LncRNAs in Lung Squamous Cell Carcinomas.

Lung squamous cell carcinoma (Lung SCC) is associated with metastatic disease, resulting in poor clinical prognosis and a low survival rate. The aberrant epithelial-mesenchymal transition (EMT) and long non-coding RNA (LncRNA) are critical attributors to tumor metastasis and invasiveness in Lung SCC. The present study divided lncRNAs into two subtypes, C1 and C2 (Cluster 1 and Cluster 2), according to the correlation of EMT activity within the public TCGA and GEO databases. Subsequently, the differential clinical characteristics, mutations, molecular pathways and immune cell deconvolution between C1 and C2 were evaluated. Lastly, we further identified three key lncRNAs (DNM3OS, MAGI2-AS3 and LINC01094) that were associated with EMT and, at the same time, prognostic for the clinical outcomes of Lung SCC patients. Our study may provide a new paradigm of metastasis-associated biomarkers for predicting the prognosis of Lung SCC.

GABPA-activated TGFBR2 transcription inhibits aggressiveness but is epigenetically erased by oncometabolites in renal cell carcinoma.

BACKGROUND: The ETS transcription factor GABPA has long been thought of as an oncogenic factor and recently suggested as a target for cancer therapy due to its critical effect on telomerase activation, but the role of GABPA in clear cell renal cell carcinoma (ccRCC) is unclear. In addition, ccRCC is characterized by metabolic reprograming with aberrant accumulation of L-2-hydroxyglurate (L-2HG), an oncometabolite that has been shown to promote ccRCC development and progression by inducing DNA methylation, however, its downstream effectors remain poorly defined. METHODS: siRNAs and expression vectors were used to manipulate the expression of GABPA and other factors and to determine cellular/molecular and phenotypic alterations. RNA sequencing and ChIP assays were performed to identify GABPA target genes. A human ccRCC xenograft model in mice was used to evaluate the effect of GABPA overexpression on in vivo tumorigenesis and metastasis. ccRCC cells were incubated with L-2-HG to analyze GABPA expression and methylation. We carried out immunohistochemistry on patient specimens and TCGA dataset analyses to assess the effect of GABPA on ccRCC survival. RESULTS: GABPA depletion, although inhibiting telomerase expression, robustly enhanced proliferation, invasion and stemness of ccRCC cells, whereas GABPA overexpression exhibited opposite effects, strongly inhibiting in vivo metastasis and carcinogenesis. TGFBR2 was identified as the GABPA target gene through which GABPA governed the TGFß signaling to dictate ccRCC phenotypes. GABPA and TGFBR2 phenocopies each other in ccRCC cells. Higher GABPA or TGFBR2 expression predicted longer survival in patients with ccRCC. Incubation of ccRCC cells with L-2-HG mimics GABPA-knockdown-mediated phenotypic alterations. L-2-HG silenced the expression of GABPA in ccRCC cells by increasing its methylation. CONCLUSIONS: GABPA acts as a tumor suppressor by stimulating TGFBR2 expression and TGFß signaling, while L-2-HG epigenetically inhibits GABPA expression, disrupting the GABPA-TGFß loop to drive ccRCC aggressiveness. These results exemplify how oncometabolites erase tumor suppressive function for cancer development/progression. Restoring GABPA expression using DNA methylation inhibitors or other approaches, rather than targeting it, may be a novel strategy for ccRCC therapy.

A2B adenosine receptor antagonists rescue lymphocyte activity in adenosine-producing patient-derived cancer models.

BACKGROUND: Adenosine is a metabolite that suppresses antitumor immune response of T and NK cells via extracellular binding to the two subtypes of adenosine-2 receptors, A2ARs. While blockade of the A2AARs subtype effectively rescues lymphocyte activity, with four A2AAR antagonists currently in anticancer clinical trials, less is known for the therapeutic potential of the other A2BAR blockade within cancer immunotherapy. Recent studies suggest the formation of A2AAR/A2BAR dimers in tissues that coexpress the two receptor subtypes, where the A2BAR plays a dominant role, suggesting it as a promising target for cancer immunotherapy. METHODS: We report the synthesis and functional evaluation of five potent A2BAR antagonists and a dual A2AAR/A2BAR antagonist. The compounds were designed using previous pharmacological data assisted by modeling studies. Synthesis was developed using multicomponent approaches. Flow cytometry was used to evaluate the phenotype of T and NK cells on A2BAR antagonist treatment. Functional activity of T and NK cells was tested in patient-derived tumor spheroid models. RESULTS: We provide data for six novel small molecules: five A2BAR selective antagonists and a dual A2AAR/A2BAR antagonist. The growth of patient-derived breast cancer spheroids is prevented when treated with A2BAR antagonists. To elucidate if this depends on increased lymphocyte activity, immune cells proliferation, and cytokine production, lymphocyte infiltration was evaluated and compared with the potent A2AAR antagonist AZD-4635. We find that A2BAR antagonists rescue T and NK cell proliferation, IFNγ and perforin production, and increase tumor infiltrating lymphocytes infiltration into tumor spheroids without altering the expression of adhesion molecules. CONCLUSIONS: Our results demonstrate that A2BAR is a promising target in immunotherapy, identifying ISAM-R56A as the most potent candidate for A2BAR blockade. Inhibition of A2BAR signaling restores T cell function and proliferation. Furthermore, A2BAR and dual A2AAR/A2BAR antagonists showed similar or better results than A2AAR antagonist AZD-4635 reinforcing the idea of dominant role of the A2BAR in the regulation of the immune system.

Long non-coding RNA MEG3 promotes cisplatin-induced nephrotoxicity through regulating AKT/TSC/mTOR-mediated autophagy.

Cis-Diamminedichloroplatinum (II) (DDP)-induced nephrotoxicity (DDPIN) may cause irreversible renal injury associated with high morbidity and mortality. Current standard therapies have not achieved satisfactory clinical outcomes due to unclear molecular and cellular mechanisms. Therefore, exploring potential therapies on DDPIN represents an urgent medical need. Present study characterized the role of lncRNA maternally expressed gene 3 (lnc-MEG3) in the pathogenesis of DDPIN. In both in vitro and in murine models of DDP-induced nephrotoxicity, lnc-MEG3 exacerbated DDPIN by negatively regulating miRNA-126 subsequently causing a decreased AKT/TSC/mTOR-mediated autophagy. By silencing lnc-MEG3 or incorporating miRNA-126 mimetics, the proliferation and migration of DDP-treated cells were restored. In vivo, we identified Paeonol to alleviate DDPIN by the inhibition of lnc-MEG3. Taken together, lnc-MEG3 represents a novel therapeutic target for DDPIN and Paeonol may serve as a promising treatment by inhibiting lnc-MEG3 and its related signaling pathways.

Local transmission and global dissemination of New Delhi Metallo-Beta-Lactamase (NDM): a whole genome analysis.

BACKGROUND: New Delhi metallo-ß-lactamase (bla NDM), a plasmid-borne carbapenemase gene associated with significant mortality and severely limited treatment options, is of global public health concern as it is found in extremely diverse Gram-negative bacterial strains. This study thus aims to genetically characterize local and global spread of bla NDM. METHODS: To investigate local transmission patterns in the context of a single hospital, whole genome sequencing data of the first 11 bla NDM-positive bacteria isolated in a local hospital were analyzed to: (1) identify and compare bla NDM-positive plasmids; and (2) study the phylogenetic relationship of the bacteria chromosomes. The global analysis was conducted by analyzing 2749 complete plasmid sequences (including 39 bla NDM-positive plasmids) in the NCBI database, where: (1) the plasmids were clustered based on their gene composition similarity; (2) phylogenetic study was conducted for each bla NDM-positive plasmid cluster to infer the phylogenetic relationship within each cluster; (3) gene transposition events introducing bla NDM into different plasmid backbones were identified; and (4) clustering pattern was correlated with the plasmids' incompatibility group and geographical distribution. RESULTS: Analysis of the first 11 bla NDM-positive isolates from a single hospital revealed very low bla NDM-positive plasmid diversity. Local transmission was characterized by clonal spread of a predominant plasmid with 2 sporadic instances of plasmid introduction. In contrast to the low diversity locally, global bla NDM spread involved marked plasmid diversity with no predominant bacterial clone. Thirty-nine (1.4 %) out of the 2749 complete plasmid sequences were bla NDM-positive, and could be resolved into 7 clusters, which were associated with plasmid incompatibility group and geographical distribution. The bla NDM gene module was witnessed to mobilize between different plasmid backbones on at least 6 independent occasions. CONCLUSIONS: Our analysis revealed the complex genetic pathways of bla NDM spread, with global dissemination characterized mainly by transposition of the bla NDM gene cassette into varied plasmids. Early local transmission following plasmid introduction is characterized by plasmid conjugation and bacterial spread. Our findings emphasize the importance of plasmid molecular epidemiology in understanding bla NDM spread.

Galectin-1 as a potent target for cancer therapy: role in the tumor microenvironment.

The microenvironment of a tumor is a highly complex milieu, primarily characterized by immunosuppression, abnormal angiogenesis, and hypoxic regions. These features promote tumor progression and metastasis, resulting in poor prognosis and greater resistance to existing cancer therapies. Galectin-1 is a ß-galactoside binding protein that is abundantly secreted by almost all types of malignant tumor cells. The expression of galectin-1 is regulated by hypoxia-inducible factor-1 (HIF-1) and it plays vital pro-tumorigenic roles within the tumor microenvironment. In particular, galectin-1 suppresses T cell-mediated cytotoxic immune responses and promotes tumor angiogenesis. However, since galectin-1 displays many different activities by binding to a number of diverse N- or O-glycan modified target proteins, it has been difficult to fully understand how galectin-1 supports tumor growth and metastasis. This review explores the importance of galectin-1 and glycan expression patterns in the tumor microenvironment and the potential effects of inhibiting galectin-1 as a therapeutic target for cancer treatment.