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Gastric cancer (GC) develops through deregulation of gene expression and accumulation of epigenetic abnormalities, leading to tumor cell acquisition of malignant features. MicroRNAs (miRNAs) play a critical role in cancer development where they can act as oncogenes or oncosuppressors. To identify miRNAs that are associated with some clinicopathologic features of GC and/or participate in tumor progression, miRNA expression in 20 GC tissues and five corresponding non‐neoplastic gastric mucosa was examined by miRNA microarray. Oligonucleotide array analysis was carried out for miRNA target prediction. The functions of candidate miRNAs and their target genes were also analyzed by quantitative RT‐PCR, Western blotting, reporter gene assay, and cell invasion assay. Comparison of miRNA expression profiles revealed that downregulation of miR‐148a was identified in most of the GC tissues. Downregulation of miR‐148a was significantly correlated with an advanced clinical stage, lymph node metastasis, and poor clinical outcome. Custom oligonucleotide array analysis revealed that MMP7 expression was markedly downregulated in miR‐148a‐overexpressing GC cells; MMP7 was found to be a direct and functional target of miR‐148a, participating in cell invasion. These results suggest that miR‐148a contributes to the maintenance of homeostasis in normal stomach tissue and plays an important role in GC invasion by regulating MMP7 expression. miR‐148a expression was significantly downregulated in gastric cancer, and its downregulation was significantly correlated with an worse clinico‐pathologic characters. MMP7 was found to be a direct and functional target of miR‐148a, participating in cell invasion.

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies worldwide. In the present study, to identify novel prognostic markers or therapeutic targets for ESCC, we reviewed a list of genes with upregulated expression in ESCC compared with normal esophagus, as identified by our serial analysis of gene expression (SAGE) analysis. We focused on the NRD1 gene, which encodes the nardilysin protein. Quantitative reverse transcription–polymerase chain reaction (qRT‐PCR) in 34 ESCC tissue samples revealed that mRNA expression of NRD1 was upregulated in 56% of ESCC tissue samples. Immunohistochemical analysis of nardilysin in 109 ESCC tissue samples demonstrated that 43 (39%) ESCC cases were positive for nardilysin. Nardilysin‐positive ESCC cases were more advanced in terms of T classification (P = 0.0007), N classification (P = 0.0164), and tumor stage (P < 0.0001) than nardilysin‐negative ESCC cases. Furthermore, nardilysin expression was significantly associated with poorer prognosis (P = 0.0258). Univariate and multivariate analyses revealed that nardilysin expression is an independent prognostic classifier of patients with ESCC. The invasiveness of NRD1‐knockdown TE1 and TE5 esophageal cancer cell lines was less than that of the negative control siRNA‐transfected cell lines. Expression of MMP2 and MMP3 mRNA was significantly lower in NRD1‐knockdown TE5 cells than in negative control siRNA‐transfected cells. These results suggest that nardilysin is involved in tumor progression, and is an independent prognostic classifier in patients with ESCC. Univariate and multivariate analyses revealed that nardilysin expression is an independent prognostic classifier of patients with esophageal squamous cell carcinoma. The invasiveness of NRD1‐knockdown TE1 and TE5 esophageal cancer cell lines was less than that of the negative control siRNA‐transfected cell lines. These results suggest that nardilysin is involved in tumor progression, and is an independent prognostic classifier in patients with esophageal squamous cell carcinoma.

Unfolded protein response (UPR) is a central stress response pathway that is hijacked by tumor cells for their survival. Here, we find that IRE1α signaling, one of the canonical UPR arms, is increased in prostate cancer (PCa) patient tumors. Genetic or small molecule inhibition of IRE1α in syngeneic mouse PCa models and an orthotopic model decreases tumor growth. IRE1α ablation in cancer cells potentiates interferon responses and activates immune system related pathways in the tumor microenvironment (TME). Single-cell RNA-sequencing analysis reveals that targeting IRE1α in cancer cells reduces tumor-associated macrophage abundance. Consistently, the small molecule IRE1α inhibitor MKC8866, currently in clinical trials, reprograms the TME and enhances anti-PD-1 therapy. Our findings show that IRE1α signaling not only promotes cancer cell growth and survival but also interferes with anti-tumor immunity in the TME. Thus, targeting IRE1α can be a promising approach for improving anti-PD-1 immunotherapy in PCa. The IRE1α-XBP1s pathway has been implicated in the regulation of anti-tumor immunity. Here the authors show that IRE1α is increased in prostate cancer (PCa) and that its inhibition reprograms the tumor microenvironment, promoting anti-tumor immune responses in PCa preclinical models.

Background Gastric cancer (GC) is the fifth commonest malignancy worldwide and still one of the leading causes of cancer-related death. The aim of this study was to identify a novel prognostic marker or therapeutic target for GC. Methods We analyzed candidate genes from our previous Escherichia coli ampicillin secretion trap (CAST) libraries in detail, and focused on the FKTN gene because it was overexpressed in both GC cell line CAST libraries, MKN-1 and MKN-45. Results Quantitative reverse transcriptase PCR analysis of FKTN revealed that FKTN messenger RNA was overexpressed in nine of 28 (32.1 %) GC tissue samples compared with nonneoplastic gastric mucosa. Immunostaining of fukutin showed that 297 of 695 cases (42.7 %) were positive for fukutin. Fukutin-positive GC cases were significantly associated with differentiated histological features, and advanced T grade and N grade. In addition, fukutin expression was observed more frequently in the intestinal phenotype (51 %) of GC than in other phenotypes (37 %) when defined by the expression patterns of mucin 5AC, mucin 6, mucin 2, and CD10. FKTN small interfering RNA treatment decreased GC cell proliferation. Conclusions These results indicate that the expression of fukutin may be a key regulator for progression of GC with the intestinal mucin phenotype.

Background Malignant peritoneal mesothelioma (PeM) is a rare and fatal cancer that originates from the peritoneal lining of the abdomen. Standard treatment of PeM is limited to cytoreductive surgery and/or chemotherapy, and no effective targeted therapies for PeM exist. Some immune checkpoint inhibitor studies of mesothelioma have found positivity to be associated with a worse prognosis. Methods To search for novel therapeutic targets for PeM, we performed a comprehensive integrative multi-omics analysis of the genome, transcriptome, and proteome of 19 treatment-naïve PeM, and in particular, we examined BAP1 mutation and copy number status and its relationship to immune checkpoint inhibitor activation. Results We found that PeM could be divided into tumors with an inflammatory tumor microenvironment and those without and that this distinction correlated with haploinsufficiency of BAP1 . To further investigate the role of BAP1 , we used our recently developed cancer driver gene prioritization algorithm, HIT’nDRIVE, and observed that PeM with BAP1 haploinsufficiency form a distinct molecular subtype characterized by distinct gene expression patterns of chromatin remodeling, DNA repair pathways, and immune checkpoint receptor activation. We demonstrate that this subtype is correlated with an inflammatory tumor microenvironment and thus is a candidate for immune checkpoint blockade therapies. Conclusions Our findings reveal BAP1 to be a potential, easily trackable prognostic and predictive biomarker for PeM immunotherapy that refines PeM disease classification. BAP1 stratification may improve drug response rates in ongoing phases I and II clinical trials exploring the use of immune checkpoint blockade therapies in PeM in which BAP1 status is not considered. This integrated molecular characterization provides a comprehensive foundation for improved management of a subset of PeM patients.

Lineage plasticity of prostate cancer is associated with resistance to androgen receptor (AR) pathway inhibition (ARPI) and supported by a reactive tumor microenvironment. Here we show that changes in chondroitin sulfate (CS), a major glycosaminoglycan component of the tumor cell glycocalyx and extracellular matrix, is AR-regulated and promotes the adaptive progression of castration-resistant prostate cancer (CRPC) after ARPI. AR directly represses transcription of the 4- O -sulfotransferase gene CHST11 under basal androgen conditions, maintaining steady-state CS in prostate adenocarcinomas. When AR signaling is inhibited by ARPI or lost during progression to non-AR-driven CRPC as a consequence of lineage plasticity, CHST11 expression is unleashed, leading to elevated 4- O -sulfated chondroitin levels. Inhibition of the tumor cell CS glycocalyx delays CRPC progression, and impairs growth and motility of prostate cancer after ARPI. Thus, a reactive CS glycocalyx supports adaptive survival and treatment resistance after ARPI, representing a therapeutic opportunity in patients with advanced prostate cancer. Chondroitin sulfate (CS) is one of the most abundant glycosaminoglycans in prostate cancers. Here the authors show that inhibition of the androgen receptor pathway leads to the upregulation of CS, which promotes prostate cancer growth and metastasis.

Prostate is the most frequent cancer in men. Prostate cancer progression is driven by androgen steroid hormones, and delayed by androgen deprivation therapy (ADT). Androgens control transcription by stimulating androgen receptor (AR) activity, yet also control pre-mRNA splicing through less clear mechanisms. Here we find androgens regulate splicing through AR-mediated transcriptional control of the epithelial-specific splicing regulator ESRP2. Both ESRP2 and its close paralog ESRP1 are highly expressed in primary prostate cancer. Androgen stimulation induces splicing switches in many endogenous ESRP2-controlled mRNA isoforms, including splicing switches correlating with disease progression. ESRP2 expression in clinical prostate cancer is repressed by ADT, which may thus inadvertently dampen epithelial splice programmes. Supporting this, treatment with the AR antagonist bicalutamide (Casodex) induced mesenchymal splicing patterns of genes including FLNB and CTNND1. Our data reveals a new mechanism of splicing control in prostate cancer with important implications for disease progression. Cancers often begin as cells that grow in connected sheets or clumps known as epithelial cells. To spread, the cancer cells need to change into cells that can break away from the group and move through the tissues. In prostate cancer, this process can happen years after successful treatment, but researchers are not sure why. Prostate cancer grows in response to testosterone. This hormone circulates around the body, and when it goes into a cell it helps select which genes are switched on or off. Testosterone-blocking drugs can help slow prostate cancer growth by changing this switching on and off of genes. But, over time, some cancers become resistant to the effects of these drugs and start to spread. This may be down to complexities in how testosterone controls gene activity. To produce a protein, a human cell first makes a copy of the corresponding gene. This copy is then modified, cutting and pasting different parts of the sequence (a process called ‘splicing’) before the protein is produced. The patterns of splicing a cell exhibits depend on splicing regulator proteins. Testosterone can change splicing patterns in prostate cancer cells, but researchers did not know how. To find out, Munkley et al. examined a set of genes that turn off in response to testosterone-blocking drugs in people with prostate cancer. This revealed that testosterone controls a master splicing regulator called ESRP2, which is normally present in epithelial cells. In prostate cancer cells in mice, extra ESRP2 slowed tumour growth. But, although ESRP2 levels are high in human prostate cancer cells to begin with, they drop in response to testosterone-blocking drugs. In the laboratory grown cells, the result was a switch away from 'epithelial-like' gene splicing patterns. Some of the new splicing patterns correlated with better patient prognosis, but other splicing patterns might help cancer cells to spread around the body. These results raise the possibility that blocking testosterone may impair prostate cancer growth, but also inadvertently prepare cancer cells to break away from tumours. A more complete understanding of how testosterone controls splicing could help explain why some tumours initially shrink when testosterone is blocked, but then later spread. Identifying the genes controlled by ESRP2 may reveal new drug targets to improve prostate cancer treatment.

Glycosaminoglycans are often deprioritized as targets for synthetic immunotherapy due to the complexity of glyco-epitopes and limited options for obtaining specific subtype binding. Solid tumors express proteoglycans that are modified with oncofetal chondroitin sulfate (CS), a modification normally restricted to the placenta. Here, we report the design and functionality of transient chimeric antigen receptor (CAR) T cells with selectivity to oncofetal CS. Following expression in T cells, the CAR could be “armed” with recombinant VAR2CSA lectins (rVAR2) to target tumor cells expressing oncofetal CS. While unarmed CAR T cells remained inactive in the presence of target cells, VAR2-armed CAR T cells displayed robust activation and the ability to eliminate diverse tumor cell types in vitro. Cytotoxicity of the CAR T cells was proportional to the concentration of rVAR2 available to the CAR, offering a potential molecular handle to finetune CAR T cell activity. In vivo, armed CAR T cells rapidly targeted bladder tumors and increased the survival of tumor-bearing mice. Thus, our work indicates that cancer-restricted glycosaminoglycans may be exploited as potential targets for CAR T cell therapy. Synopsis Transient VAR2-[SpyT][SpyC]-CAR T cells targeting oncofetal chondroitin sulfate (CS) show high specificity and activity against solid tumor cells, adding glycosaminoglycans to the list of potential actionable targets for CAR T cell therapy in solid tumors. Transient CAR T cells were developed to target oncofetal CS, unique to cancer cells. VAR2-[SpyT]-armed CAR T cells demonstrated robust activation, cytokine production, and cytotoxicity in vitro. The targeting mechanism offers high specificity and potential broad applicability across various solid tumors. VAR2-[SpyT][SpyC]-CAR T cells inhibited tumor growth and increased survival in vivo. The VAR2-[SpyT][SpyC]-CAR T cell system provides proof-of-concept for oncofetal CS as a potential target for CAR T cell approaches. Transient VAR2-[SpyT][SpyC]-CAR T cells targeting oncofetal chondroitin sulfate (CS) show high specificity and activity against solid tumor cells, adding glycosaminoglycans to the list of potential actionable targets for CAR T cell therapy in solid tumors.

MYC family proteins are implicated in many human cancers, but their therapeutic targeting has proven challenging. MYCN amplification in childhood neuroblastoma (NB) is associated with aggressive disease and high mortality. Novel and effective therapeutic strategies are therefore urgently needed for these tumors. MYC-driven oncogenic transformation impairs cell survival under nutrient deprivation (ND), a characteristic stress condition within the tumor microenvironment. We recently identified eukaryotic Elongation Factor 2 Kinase (eEF2K) as a pivotal mediator of the adaptive response of tumor cells to ND. We therefore hypothesized that eEF2K facilitates the adaptation of MYCN amplified NB to ND, and that inhibiting this pathway can impair MYCN-driven NB progression. To test our hypothesis, we first analyzed publicly available genomic databases and tissue microarrays for eEF2K expression in NB, and for links between eEF2K , MYCN , and clinical outcome in NB. Effects of eEF2K inhibition were evaluated on survival of MYCN amplified versus non-amplified NB cell lines under ND. Finally, NB xenograft mouse models were used to confirm in vitro observations. Our results indicate that high eEF2K expression and activity are strongly predictive of poor outcome in NB, and correlates significantly with MYCN amplification. Inhibition of eEF2K markedly decreases survival of MYCN amplified NB cell lines in vitro under ND. Growth of MYCN amplified NB xenografts is markedly impaired by eEF2K knockdown, particularly under caloric restriction. In summary, eEF2K protects MYCN overexpressing NB cells from ND in vitro and in vivo , highlighting this kinase as a critical mediator of the adaptive response of MYCN amplified NB cells to metabolic stress.

Proteoglycans are proteins that are modified with glycosaminoglycan chains. Chondroitin sulfate proteoglycans (CSPGs) are currently being exploited as targets for drug-delivery in various cancer indications, however basic knowledge on how CSPGs are internalized in tumor cells is lacking. In this study we took advantage of a recombinant CSPG-binding lectin VAR2CSA (rVAR2) to track internalization and cell fate of CSPGs in tumor cells. We found that rVAR2 is internalized into cancer cells via multiple internalization mechanisms after initial docking on cell surface CSPGs. Regardless of the internalization pathway used, CSPG-bound rVAR2 was trafficked to the early endosomes in an energy-dependent manner but not further transported to the lysosomal compartment. Instead, internalized CSPG-bound rVAR2 proteins were secreted with exosomes to the extracellular environment in a strictly chondroitin sulfate-dependent manner. In summary, our work describes the cell fate of rVAR2 proteins in tumor cells after initial binding to CSPGs, which can be further used to inform development of rVAR2-drug conjugates and other therapeutics targeting CSPGs.