Evidence indicates that the lipid scavenger receptor CD36 has pro-metastatic functions in several cancers. Although CD36 expression correlates with an unfavorable prognosis in gastric cancer (GC), its specific contribution to disease onset, progression, and/or metastasis remains unclear. Using bioinformatics analyses, we ascertained that CD36 expression was increased in metastatic GC specimens in The Cancer Genome Atlas and Gene Expression Omnibus databases and correlated with poor prognosis. In addition, higher CD36 expression was associated with lymph node metastasis ( p < 0.05) and poor prognosis ( p = 0.030) in 79 Chinese GC patients. Basal CD36 expression levels correlated positively with migration, invasion, and expression of epithelial-to-mesenchymal transition (EMT) markers in GC cell lines, a relationship confirmed by knockdown and overexpression experiments. Importantly, analysis of gene expression changes in CD36-knockdown GC cells led us to identify the chromatin-associated protein DEK as a c-Myc target that mediates activation of the GSK-3β/β-catenin signaling pathway to trigger EMT. These findings further our understanding of the mechanisms governing metastatic dissemination of GC cells and suggest the therapeutic potential of strategies targeting CD36.

The median survival time of patients with advanced gastric cancer (GC) who received radiotherapy and chemotherapy was &lt;1 year. Epithelial–mesenchymal transformation (EMT) gives GC cells the ability to invade, which is an essential biological mechanism in the progression of GC. The long non-coding RNA (lncRNA)-based competitive endogenous RNA (ceRNA) system has been shown to play a key role in the GC-related EMT process. Although the AKT pathway is essential for EMT in GC, the relationship between AKT3 subtypes and EMT in GC is unclear. Here, we evaluated the underlying mechanism of ceRNA involving NR2F1-AS1/miR-190a/PHLDB2 in inducing EMT by promoting the expression and phosphorylation of AKT3. The results of bioinformatics analysis showed that the expression of NR2F1-AS1/miR-190a/PHLDB2 in GC was positively associated with the pathological features, staging, poor prognosis, and EMT process. We performed cell transfection, qRT-PCR, western blot, cell viability assay, TUNEL assay, Transwell assay, cell morphology observation, and double luciferase assay to confirm the regulation of NR2F1-AS1/miR-190a/PHLDB2 and its effect on EMT transformation. Finally, GSEA and GO/KEGG enrichment analysis identified that PI3K/AKT pathway was positively correlated to NR2F1-AS1/miR-190a/PHLDB2 expression. AKT3 knockout cells were co-transfected with PHLDB2-OE, and the findings revealed that AKT3 expression and phosphorylation were essential for the PHLDB2-mediated EMT process. Thus, our results showed that NR2F1-AS1/miR-190a/PHLDB2 promoted the phosphorylation of AKT3 to induce EMT in GC cells. This study provides a comprehensive understanding of the underlying mechanism involved in the EMT process as well as the identification of new EMT markers.

BackgroundGastric signet ring cell carcinoma (GSRCC) is a rare disease associated with poor prognosis. A prognostic nomogram was developed and validated in this study to assess GSRCC patients’ overall survival (OS).MethodsPatients diagnosed with GSRCC from the Surveillance, Epidemiology, and End Results (SEER) database (2004–2016) and the First Hospital of China Medical University (CMU1h) were enrolled in this retrospective cohort study. Univariate and multivariate COX analysis was used to determine independent prognostic factors to construct the prognostic nomogram. Predictions were evaluated by the C-index and calibration curve. In addition, the receiver operating characteristic (ROC) curve, decision curve analysis (DCA), and Kaplan-Meier analysis were employed to assess the clinical utility of the survival prediction model.ResultsPatients were classified into two cohorts. We randomly divided patients in the SEER database and CMU1h cohort into a training group (n=3068, 80%) and a validation group (n=764, 20%). Age, race, T stage, N stage, M stage, therapy, and tumor size were significantly associated with the prognosis of GSRCC patients. On this basis, a nomogram was constructed, with a C-index in the training and the validation cohorts at 0.772 (95% CI: 0.762–0.782) and 0.774 (95% CI: 0.752–0.796), respectively. The accuracy of the generated nomogram was verified through calibration plots. Similarly, compared with the traditional AJCC staging system, the results of the area under curve (AUC) calculated by ROC, DCA, and Kaplan-Meier curves, demonstrated a good predictive value of the constructed nomogram, compared to the traditional AJCC staging system.ConclusionIn the present study, seven independent prognostic factors of GSRCC were screened out. The established nomogram models based on seven variables provided a visualization of each prognostic factor’s risk and assisted clinicians in predicting the 1-, 3-, and 5-year OS of GSRCC.