Comprehensive characterization of pyroptosis phenotypes with distinct tumor immune profiles in gastric cancer to aid immunotherapy.

OBJECTIVE: Pyroptosis is a form of programmed cell death that is essential for immunity. Herein, this study was conducted to uncover the implication of pyroptosis in immunomodulation and tumor microenvironment (TME) in gastric cancer. METHODS: Prognostic pyroptosis-related genes were extracted to identify different pyroptosis phenotypes and pyroptosis genomic phenotypes via unsupervised clustering analysis in the gastric cancer meta-cohort cohort (GSE15459, GSE62254, GSE84437, GSE26253 and TCGA-STAD). The activation of hallmark gene sets was quantified by GSVA and immune cell infiltration was estimated via ssGSEA and CIBERSORT. Through PCA algorithm, pyroptosis score was conducted. The predictors of immune response (TMB and IPS) and genetic mutations were evaluated. The efficacy of pyroptosis score in predicting immune response was verified in two anti-PD-1 therapy cohorts. RESULTS: Three different pyroptosis phenotypes with different prognosis, biological pathways and tumor immune microenvironment were established among 1275 gastric cancer patients, corresponding to three immune phenotypes: immune-inflamed, immune-desert, and immune-excluded. According to the pyroptosis score, patients were separated into high and low pyroptosis score groups. Low pyroptosis score indicated favorable survival outcomes, enhanced immune responses, and increased mutation frequency. Moreover, low pyroptosis score patients displayed more clinical benefits from anti-PD-1 and prolonged survival time. CONCLUSION: Our findings uncovered a nonnegligible role of pyroptosis in immunomodulation and TME multiformity and complicacy in gastric cancer. Quantifying the pyroptosis score in individual tumors may tailor more effective immunotherapeutic strategies.

ARFIP2 Regulates EMT and Autophagy in Hepatocellular Carcinoma in Part Through the PI3K/Akt Signalling Pathway.

Purpose: ARFIP2, a canonical BAR domain-containing protein, is closely associated with regulating cargo exit from the Golgi. However, the potential biological functions of ARFIP2 in hepatocellular carcinoma (HCC) have not been well investigated. This study aimed to explore the critical role of ARFIP2 in HCC cells. Methods: The expression of proteins related to epithelial to mesenchymal transition (EMT) and cell autophagy in HCC cells and tissues was assayed by quantitative real-time PCR, Western blotting, immunohistochemistry and immunofluorescence staining. The ability of cells to proliferate, migrate and invade was detected by Cell Counting Kit-8, Transwell migration and invasion assays. In addition, the function of ARFIP2 in vivo was assessed using a tumour xenograft model. Results: ARFIP2 expression is significantly upregulated in early recurrent and metastatic HCC patients and was positively correlated with a poor prognosis. ARFIP2 overexpression promoted cell proliferation, migration, and invasion by inducing EMT and inhibiting autophagy in vitro. Furthermore, the regulatory effects of ARFIP2 on autophagy and EMT were partially attributed to its regulation of the PI3K/AKT signalling pathway. The in vivo results also showed that ARFIP2 modulates HCC progression. Conclusion: Our results substantiate a novel mechanism by which ARFIP2 can regulate the activity/phosphorylation of Akt to promote EMT and inhibit autophagy in part via the PI3K/Akt signalling pathway. The ARFIP2/PI3K/Akt axis may be a potential diagnostic biomarker and therapeutic target for HCC.

A Novel Exosome-Relevant Molecular Classification Uncovers Distinct Immune Escape Mechanisms and Genomic Alterations in Gastric Cancer.

Objective: Gastric cancer (GC) is a highly heterogeneous malignant carcinoma. This study aimed to conduct an exosome-based classification for assisting personalized therapy for GC. Methods: Based on the expression profiling of prognostic exosome-related genes, GC patients in The Cancer Genome Atlas (TCGA) cohort were classified using the unsupervised consensus clustering approach, and the reproducibility of this classification was confirmed in the GSE84437 cohort. An exosome-based gene signature was developed via Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis. Immunological features, responses to immune checkpoint inhibitors, and genetic alterations were evaluated via computational methods. Results: Two exosome-relevant phenotypes (A and B) were clustered, and this classification was independent of immune subtypes and TCGA subtypes. Exosome-relevant phenotype B had a poorer prognosis and an inflamed tumor microenvironment (TME) relative to phenotype A. Patients with phenotype B presented higher responses to the anti-CTLA4 inhibitor. Moreover, phenotype B occurred at a higher frequency of genetic mutation than phenotype A. The exosome-based gene signature (GPX3, RGS2, MATN3, SLC7A2, and SNCG) could independently and accurately predict GC prognosis, which was linked to stromal activation and immunosuppression. Conclusion: Our findings offer a conceptual frame to further comprehend the roles of exosomes in immune escape mechanisms and genomic alterations of GC. More work is required to evaluate the reference value of exosome-relevant phenotypes for designing immunotherapeutic regimens.

Omeprazole improves chemosensitivity of gastric cancer cells by m6A demethylase FTO-mediated activation of mTORC1 and DDIT3 up-regulation.

The curative effect for patients with advanced gastric cancer is still unsatisfactory. Proton pump inhibitors could be a promising treatment strategy that could sensitize gastric cancer cells to antitumor drugs further; however, the underlying molecular mechanism remains to be further elucidated. In this research, it was found that omeprazole pretreatment could enhance the inhibitory effect of 5-Fu, DDP and TAX on gastric cancer cells. Interestingly, omeprazole pretreatment enhanced the total m6A level of cells due to the decreased FTO. TCGA analysis showed that FTO expression is up-regulated in GC tissues and is negatively correlated with disease-free survival of GC patients. It was also found that FTO inhibition induced by omeprazole enhanced the activation of mTORC1 signal pathway that inhibited the prosurvival autophagy so as to improve the antitumor efficiency of chemotherapeutic drugs on GC cells. Meanwhile, transcript level of DDIT3, which is an apoptosis-related tumor suppressor gene downstream of mTORC1, was regulated by omeprazole-induced FTO silence through an m6A-dependent mechanism. The present study, for the first time, found that m6A modification and its eraser FTO may play a role in the improvement of chemosensitivity mediated by proton pump inhibitor omeprazole.

Protective and anti-inflammatory role of REG1A in inflammatory bowel disease induced by JAK/STAT3 signaling axis.

Regenerating islet-derived protein 1-alpha (REG1A) was abnormally upregulated in a series of gastrointestinal inflammatory disorders. However, the potential biological function and underlying regulatory mechanisms of the increased REG1A in inflammatory bowel disease (IBD) pathogenesis remain to be fully elucidated. In this study, we uncovered that REG1A was substantially increased in the inflamed colorectal tissues of IBD patients. And the aberrantly expressed REG1A in intestinal epithelial cells (IEC) prominently inhibited inflammatory responses, promoted cell proliferation and suppressed epithelial apoptosis. Mechanically, IL-6 and IL-22 markedly activated REG1A transcription through triggering JAK/STAT3 signaling pathway. In addition, overexpression of REG1A in mice by systematic delivery of REG1A lentivirus remarkably alleviated DSS-induced inflammatory injury and maintained the integrity of intestinal mucosal barrier. Taken together, our data demonstrated that the novel proliferative factor REG1A controlled by IL-6/IL-22-JAK-STAT3 signaling may provide a promising therapeutic target for patients with IBD.

Molecular correlates and prognostic value of tmTNF-α expression in colorectal cancer of 5-Fluorouracil-Based Adjuvant Therapy.

Transmembrane tumor necrosis factor-α (tmTNF-α) is known to induce the activation of NF-κB to protect tumor cells. Upregulation of tmTNF-α leads to resistance to apoptosis and induces drug resistance in breast cancer. However, the expression of tmTNF-α in colorectal cancer (CRC) and its association with clinical outcome in CRC have remained unclear. In this study, we examined the tmTNF-α expression in CRC by immunohistochemistry and western blotting, assessed the prognostic value of tmTNF-α related to the recurrence/metastasis and survival of stage II/III CRC by the Kaplan-Meier survival curve and Cox regression model, and also explored the role of tmTNF-α expression on the chemotherapeutic efficacy of 5-Fluorouracil by flow cytometry assay and cell counting kit-8 (CCK-8) in vitro. Overall, we found that 77 (78.6%) out of 98 patients exhibited higher tmTNF-α expression in the CRC tissues comparing with the adjacent tissues. The tmTNF-α expression was correlated with Differentiation (P = 0.019), TNM stage (P = 0.039), Lymph nodes metastasis (P = 0.024) and Lymphovascular invasion (P = 0.027) but not related with Age (P = 0.617), Gender (P = 0.625), Tumor location (P = 0.138), Perforation/Obstruction (P = 1.000), Depth of invasion (P = 0.327), and microsatellite instability status (P = 0.150). The prognostic analyses showed that high tmTNF-α expression patients was significantly associated with decreased Disease-Free Survival (P = 0.0209) and Overall Survival (P = 0.0163). CCK-8 results suggested that the tmTNF-α influenced the chemotherapeutic effect of 5-Fluorouracil on colon cancer cells. Altogether, these data indicated the stageII/III CRC patients with high tmTNF-α expression were more likely to have a worse prognosis than patients with low tmTNF-α expression and tmTNF-α may influence the chemotherapeutic effect of 5-Fluorouracil. The mechanism for these observations warrants further study.

Evaluation of effects of thymidylate synthase and excision repair cross-complementing 1 polymorphisms on chemotherapy outcome in patients with gastrointestinal tumors using peripheral venous blood.

The aim of the present study was to evaluate the effects of thymidylate synthase (TYMS) and excision repair cross-complementing 1 (ERCC1) polymorphisms on chemotherapeutic efficacy in patients with gastrointestinal tumors using peripheral venous blood. Preoperative peripheral venous blood and tumor tissue samples of 43 patients with gastric cancer and the peripheral venous blood samples of 76 patients with cancer who underwent chemotherapy were studied. The 3R/3R and 2R/2R or 2R/3R genotypes of TYMS were identified in 72.09 and 27.91%, respectively (P<0.01), of untreated patients, and the C/C and T/T or C/T genotypes of ERCC1 were present in 81.39 and 18.61%, respectively (P<0.01), of patients. The 3R/3R and 2R/2R or 2R/3R genotypes of TYMS were identified in 65.79 and 34.21%, respectively, of chemotherapy-treated patients. The overall response rates (ORRs) for the two aforementioned genotypes were 18.00 and 57.69%, respectively (P<0.01), and those for the C/C and T/T or C/T genotypes of ERCC1 were 63.16 and 36.84%, respectively. The ORRs were 47.91 and 3.57%, respectively (P<0.01). In conclusion, peripheral blood samples may be used to replace tumor tissue for detecting TYMS and ERCC1 polymorphisms, and may be used to evaluate the efficacy of 5-fluorouracil and platinum drugs.

Increased expression of Notch 1 in a rat liver transplantation model.

Liver transplantation is the standard treatment for end­stage liver failure; however, rejection can result in allograft failure. In order to investigate the role of Notch 1 during rejection, the present study evaluated Notch 1 expression, as well as the levels of immune reactivity, in rat liver allografts. A heterotopic liver transplantation model was established using Dark Agouti (DA) rats as donors and Lewis rats as recipients (DA/Lewis), with DA recipient rats serving as controls (DA/DA). The concentration levels of immune reactivity markers and serum Notch 1 were measured on days 3, 5, and 7. The overall survival was significantly shorter (<10 days) in the DA/Lewis group, as compared with the DA/DA group (P<0.0001). The concentration levels of serum alanine aminotransferase and total bilirubin were significantly higher 5 and 7 days following transplantation in the DA/Lewis group, as compared with the DA/DA group (P<0.001). The concentration levels of serum Notch 1 were significantly higher in the DA/Lewis group, as compared with the DA/DA group on days 3, 5, and 7 following transplantation (P<0.0001). These results indicate that the expression levels of serum Notch 1 significantly increase during liver allograft rejection, suggesting that Notch 1 is involved in the mechanism underlying liver allograft rejection. Notch 1 may serve as a marker of acute rejection in a rat liver transplantation model.