IL-17 induces NSCLC cell migration and invasion by elevating MMP19 gene transcription and expression through the interaction of p300-dependent STAT3-K631 acetylation and its Y705-phosphorylation.

The cancer cell metastasis is a major death reason for patients with non-small cell lung cancer (NSCLC). Although researchers have disclosed that interleukin 17 (IL-17) can increase matrix metalloproteinases (MMPs) induction causing NSCLC cell metastasis, the underlying mechanism remains unclear. In the study, we found that IL-17 receptor A (IL-17RA), p300, p-STAT3, Ack-STAT3, and MMP19 were up-regulated both in NSCLC tissues and NSCLC cells stimulated with IL-17. p300, STAT3 and MMP19 overexpression or knockdown could raise or reduce IL-17-induced p-STAT3, Ack-STAT3 and MMP19 level as well as the cell migration and invasion. Mechanism investigation revealed that STAT3 and p300 bound to the same region (-544 to -389 nt) of MMP19 promoter, and p300 could acetylate STAT3-K631 elevating STAT3 transcriptional activity, p-STAT3 or MMP19 expression and the cell mobility exposed to IL-17. Meanwhile, p300-mediated STAT3-K631 acetylation and its Y705-phosphorylation could interact, synergistically facilitating MMP19 gene transcription and enhancing cell migration and invasion. Besides, the animal experiments exhibited that the nude mice inoculated with NSCLC cells by silencing p300, STAT3 or MMP19 gene plus IL-17 treatment, the nodule number, and MMP19, Ack-STAT3, or p-STAT3 production in the lung metastatic nodules were all alleviated. Collectively, these outcomes uncover that IL-17-triggered NSCLC metastasis involves up-regulating MMP19 expression via the interaction of STAT3-K631 acetylation by p300 and its Y705-phosphorylation, which provides a new mechanistic insight and potential strategy for NSCLC metastasis and therapy.

First-line camrelizumab (a PD-1 inhibitor) plus apatinib (an VEGFR-2 inhibitor) and chemotherapy for advanced gastric cancer (SPACE): a phase 1 study.

Patients with advanced gastric cancer typically face a grim prognosis. This phase 1a (dose escalation) and phase 1b (dose expansion) study investigated safety and efficacy of first-line camrelizumab plus apatinib and chemotherapy for advanced gastric or gastroesophageal junction adenocarcinoma. The primary endpoints included maximum tolerated dose (MTD) in phase 1a and objective response rate (ORR) across phase 1a and 1b. Phase 1a tested three dose regimens of camrelizumab, apatinib, oxaliplatin, and S-1. Dose regimen 1: camrelizumab 200 mg on day 1, apatinib 250 mg every other day, oxaliplatin 100 mg/m² on day 1, and S-1 40 mg twice a day on days 1-14. Dose regimen 2: same as dose regimen 1, but oxaliplatin 130 mg/m². Dose regimen 3: same as dose regimen 2, but apatinib 250 mg daily. Thirty-four patients were included (9 in phase 1a, 25 in phase 1b). No dose-limiting toxicities occurred so no MTD was identified. Dose 3 was set for the recommended phase 2 doses and administered in phase 1b. The confirmed ORR was 76.5% (95% CI 58.8-89.3). The median progression-free survival was 8.4 months (95% CI 5.9-not evaluable [NE]), and the median overall survival (OS) was not mature (11.6-NE). Ten patients underwent surgery after treatment and the multidisciplinary team evaluation. Among 24 patients without surgery, the median OS was 19.6 months (7.8-NE). Eighteen patients (52.9%) developed grade ≥ 3 treatment-emergent adverse events. Camrelizumab plus apatinib and chemotherapy showed favorable clinical outcomes and manageable safety for untreated advanced gastric cancer (ChiCTR2000034109).

A novel TREM1/DAP12-based multiple chain CAR-T cell targets PTK7 in ovarian cancer therapy.

While CAR-T cell therapy has shown success against hematological tumors, its effectiveness for solid tumors, including ovarian cancer, remains unsatisfactory. This study aimed to develop and evaluate the efficacy of novel chimeric antigen receptor T (CAR-T) cells targeting PTK7 through TREM1/DAP12 signaling against ovarian cancer. The expression of PTK7 in ovarian cancer tissues and cells was evaluated using immunohistochemical staining and flow cytometric analysis. The anti-tumor effects of PTK7 CAR-T cells were assessed in vitro using real-time cell analysis and enzyme-linked immunosorbent assay, and in vivo using a xenograft tumor model. PTK7 was significantly expressed in ovarian cancer tissues and cells. PTK7-targeting CAR-T cells based on TREM1/DAP12 signaling exhibited potent cytotoxicity against ovarian cancer cells expressing PTK7 in vitro, and effectively eradicated tumors in vivo. Our findings suggest that TREM1/DAP12-based PTK7 CAR-T cells have potential as a treatment strategy for ovarian cancer. Further studies are needed to evaluate the safety and efficacy of this approach in clinical trials.

IL-17 induces non-small cell lung cancer metastasis via GCN5-dependent SOX4 acetylation enhancing MMP9 gene transcription and expression.

Interleukin-17 (IL-17), a potent proinflammatory cytokine, can trigger the metastasis of non-small cell lung cancer (NSCLC). However, the underlying mechanism involved in IL-17-induced NSCLC cell metastasis remains unclear. In this study, we found that not only the expression of IL-17, IL-17RA, and/or general control nonrepressed protein 5 (GCN5), SRY-related HMG-BOX gene 4 (SOX4), and matrix metalloproteinase 9 (MMP9) was increased in the NSCLC tissues and in the IL-17-stimulated NSCLC cells, but also IL-17 treatment could enhance NSCLC cell migration and invasion. Further mechanism exploration revealed that IL-17-upregulated GCN5 and SOX4 could bind to the same region (-915 to -712 nt) of downstream MMP9 gene promoter driving its gene transcription. In the process, GCN5 could mediate SOX4 acetylation at lysine 118 (K118, a newly identified site) boosting MMP9 gene expression as well as cell migration and invasion. Moreover, the SOX4 acetylation or MMP9 induction and metastatic nodule number in the lung tissues of the BALB/c nude mice inoculated with the NSCLC cells stably infected by corresponding LV-shGCN5 or LV-shSOX4, LV-shMMP9 plus IL-17 incubation were markedly reduced. Overall, our findings implicate that NSCLC metastasis is closely associated with IL-17-GCN5-SOX4-MMP9 axis.

Anti-PD-1 plus anti-angiogenesis combined with chemotherapy in patients with HER2-negative advanced or metastatic gastric cancer: a multi-institutional retrospective study.

Background: Immunotherapy plus chemotherapy have been confirmed to be effective in treating advanced or metastatic gastric cancer (GC). Anti- programmed death-1 (PD-1) plus antiangiogenic agents have shown promising activity and tolerant toxicity in subsequent therapy of late-stage gastric cancer. The aim of this study was to assess the efficacy and safety of anti-PD-1 plus anti-angiogenic agents and chemotherapy in advanced or metastatic GC and to explore the potential biomarkers associated with response. Methods: We retrospectively reviewed thirty human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic GC patients who received PD-1 plus anti-angiogenic drugs and chemotherapy. Conversion therapy was defined when the patients could undergo resection post combination therapy. Clinical data were retrieved from medical records. We conducted exploratory biomarker analysis of baseline gene mutations and tumor mutation burden (TMB) using the next-generation sequencing (NGS), PD-L1 by immunohistochemistry (IHC), and the tumor immune microenvironment (TIME) by multiplex immunofluorescence. Results: A total of 30 patients received anti-PD-1plus anti-angiogenic drugs and chemotherapy during the study period. The objective response rate (ORR) was 76.7% [95% confidence interval (CI): 57.7-90.1%] and disease control rate (DCR) was 86.7% (95% CI: 69.3-96.2%). A total of 11 patients (36.7%) achieved conversion therapy and underwent surgery. The R0 resection rate was 90.9%. Of the 11 patients, 9 (81.8%) responded to the treatment, 1 with a pathological complete response (pCR) and 8 with a major pathological response (MPR). No adverse events of grade 3 or higher occurred. Neither PD-L1 expression nor TMB was significantly correlated with treatment response. Analysis of TIME revealed that the fraction of CD8+ T cell in the invasive margin was higher in responders than non-responders before treatment. TAM2 in the tumor center and CD8+ T cell in the invasive margin was significantly increased after combination therapy, which suggested that combination therapy promoted infiltration of CD8+ T cells, thereby exerting an antitumor effect. Conclusions: Immunotherapy plus anti-angiogenic drugs and chemotherapy is a promising treatment strategy for advanced or metastatic GC patients. Tumor infiltration CD8+ T cells may serve as potential predictive biomarker.

LOC101929709 promotes gastric cancer progression by aiding LIN28B to stabilize c-MYC mRNA.

BACKGROUND: LIN28B plays a critical role in the Warburg effect. However, its underlying mechanism remains elusive. Recently, it has been reported that LIN28B could collaborate with IGF2BP3, which can bind to m6A-modified c-MYC transcripts. Therefore, this study investigated if LIN28B recognises methylated c-MYC mRNA to promote the Warburg effect in gastric cancer. METHODS: Effects of LIN28B on gastric cancer were confirmed in vitro and in vivo. On the basis of bioinformatics analysis, the association between LIN28B and c-MYC mRNA was shown using RNA immunoprecipitation (RIP) and luciferase reporter assays. The role of m6A was identified by RNA pull-down assays. We further performed RIP-seq to search for long non-coding RNAs (lncRNAs) participating in the LIN28B binding process. Chromatin immunoprecipitation was used to show the impact of c-MYC on transcription of LIN28B and lncRNAs. RESULTS: LIN28B was identified to stabilize c-MYC mRNA by recognizing m6A. Furthermore, the interaction between c-MYC mRNA and LIN28B is speculated to be supported by LOC101929709, which binds to both LIN28B and IGF2BP3. Functional experiments revealed that LOC101929709 promotes the proliferation, migration and glycolysis of gastric cancer. Mechanistically, LOC101929709 enriched in the cytoplasm helps LIN28B stabilize c-MYC mRNA. Moreover, c-MYC promoted the transcription of both LOC101929709 and LIN28B. Additionally, LOC101929709 also activated the PI3K/AKT pathway. CONCLUSIONS: The c-MYC/LOC101929709/LIN28B axis promotes aerobic glycolysis and tumour progression. Thus, LOC101929709 can be a novel potential target for gastric cancer treatment.

Identification of a metabolism-related gene signature predicting overall survival for bladder cancer.

Reprogramming of metabolism is becoming a novel hallmark of cancer. This study aims to perform bioinformatics analysis of metabolism-related genes in bladder cancer, and to construct a signature of metabolism-related genes for predicting the prognosis. A total of 373 differentially expressed metabolism-related genes were identified from TCGA database. Taking survival time and clinical information into consideration, we constructed a risk score to predict clinical prognosis. Low-risk patients had a better prognosis than high-risk patients. Multivariate analysis showed that risk score was an independent prognostic indicator in bladder cancer. ROC curve also proved that risk score had better ability to predict prognosis than other individual indicators. Nomogram also showed a clinical net benefit to evaluate the prognosis of bladder cancer patients. GSEA revealed several metabolism-related pathways that were differentially enriched in the high-risk and low-risk groups, which might help to explain the underlying mechanisms. This signature was confirmed to be an effective prognostic biomarker in bladder cancer.

Knockdown of EphB3 inhibits cell proliferation partly through the AKT signaling pathway and represses epithelial-mesenchymal transition in esophageal squamous cell carcinoma.

Background: To investigate the role and mechanism of erythropoietin-producing hepatocyte receptor B3 (EphB3) in cancer of esophageal squamous cells. Methods: EphB3 expression in esophageal carcinoma squamous tissue and cell lines was determined by immunohistochemistry, western blotting and qRT-PCR. The viability, invasion and migration of cells were assessed by Transwell assay, formation of colonies, CCK-8, and healing of wounds, respectively. Flow cytometry analysis was employed to evaluate the actions of EphB3 on the activity of the cell cycle and the degree of apoptosis. The activity of EphB3 on the growth of tumors in vivo was examined in a mouse xenograft model. Results: EphB3 was highly expressed in esophageal squamous cell cancer tissue and was positively correlated with cell differentiation, metastasis in lymph node and the TNM stage. Patients with higher EphB3 expression had poorer prognosis in 3-year overall survival rate. EphB3 also overexpressed in esophageal squamous cell cancer cell lines. Knock down of EphB3 expression suppressed proliferation, migration and the invasion of cells in vitro and was shown to delay the growth of tumors in vivo. Silencing of EphB3 reduced the expression of pAKT, cyclinD1 and altered the epithelial-mesenchymal transition (EMT) process. Furthermore, AKT signal pathway agonist SC79 reversed EphB3 downregulation-mediated inhibition of cell proliferation, migration, invasion and EMT process. Conclusions: EphB3 knockdown inhibited the proliferation of esophageal squamous cell cancer partly through the AKT signaling pathway and repressed cell migration and invasion via EMT reversion. The findings of the study suggested that EphB3 might be a novel target for the therapy of esophageal carcinoma.

Yes-associated protein gene overexpression regulated by ß-catenin promotes gastric cancer cell tumorigenesis.

BACKGROUND: Yes-associated protein (YAP) has been reported to act as a candidate human oncogene and played a critical role in the development of multiple cancer types. OBJECTIVE: We aimed to investigate the expression, function, and underlying mechanisms of YAP in gastric cancer (GC). METHODS: Expression levels of YAP in gastric tissues were tested. CCK8 assay, clonogenic assay, apoptosis assay, transwell assay, cell scratch assay and animal study were conducted to explore the function of YAP. Chromatin immunoprecipitation (ChIP) assay and luciferase reporter assay were performed to explore the underlying mechanism. Survival analysis was carried out to reveal the relationship between YAP and clinical outcome. RESULTS: YAP was upregulated in gastric cancer tissues and correlates with poor prognosis. YAP could promote GC cells proliferation, metastatic capacity, inhibit GC cells apoptosis in vitro and in vivo. Bothß-catenin and YAP were mainly localized withi the tumor cell nuclei. ß-catenincould upregulate YAP expression by binding to the promotor region of YAP. Patients with both YAP and ß-catenin negetive expression had a better prognosis than others. CONCLUSIONS: YAP overexpression is driven by aberrant Wnt ß-catenin signalingand then contributed to the GC tumorigenesis and progression. Thus, YAP might be a potential target for GC treatment.

Apoptotic Induction of Mitochondria-Anchored Aggregation-Induced Emission Luminogens through the Intrinsic Mitochondrial Pathway.

Gastric cancer has the third highest mortality rate globally. Chemotherapy is the primary treatment used in advanced gastric cancer. Aggregation-induced emission luminogens (AIEgens) have been exploited as non-toxic and efficient chemotherapy agents for the treatment of cancer. Our previous research demonstrated that tetraphenylethene-substituted pyridinium salt (TPE-Py) is a kind of AIEgen that had the ability to lead to apoptosis in gastric cancer cells. However, it is currently unknown whether TPE-Py induced apoptosis in gastric cancer cells by the mitochondria-mediated pathway. This research confirmed that TPE-Py could target mitochondria and induce apoptotic cell death. In addition, several well-recognized indicators were detected to investigate the functional and morphological changes of mitochondria. We found that TPE-Py could diminish the mitochondrial membrane potential and increase the accumulation of reactive oxygen species and the discharge of cytochrome c, which was related to the mitochondrial apoptotic pathway. Meanwhile, morphological changes in mitochondria were also observed by transmission electron microscopy in gastric cancer cells after incubation with TPE-Py. In conclusion, we provided insights into the mechanism regulating apoptosis in gastric cancer cells and elucidated the mechanism of apoptosis induced by TPE-Py via the intrinsic mitochondrial pathway.

Coexpression of c-Jun in multiple-chain DAP-CAR-engineered T-cells for solid tumor therapy.

Aim: This work was designed to explore whether c-Jun overexpression could improve the persistence and antitumor efficacy of DAP chimeric antigen receptor T-cell (CAR-T) cells. Methods: The in vitro and in vivo antitumor effects of mesothelin (MSLN) targeting DAP-CAR-T cells were verified by ELISA, real-time cell analysis and in a xenograft model. Results: c-Jun overexpression did not affect DAP-CAR-T cell expansion while slightly increasing IL-2 secretion. Moreover, c-Jun did not improve the antitumor efficacy of DAP-CAR-T cells in vitro or in vivo, but reduced LAG3 expression and increased the ratio of Tcm and Tn/Tscm cells in vivo. Conclusion: The findings indicate that coexpression with c-Jun in DAP-CAR-T cells slightly improves T-cell exhaustion and central memory phenotype maintenance, which may be useful for DAP-CAR-T cell therapy in solid tumors.

Chimeric antigen receptor (CAR) T-cell therapy has achieved great success in treating patients with hematological tumors such as b-acute lymphoblastic leukemia and lymphoma. However, a growing number of clinical trials show that most of the second-generation CAR-T cells with different targeting single-chain fragment variables (scFv) did not exhibit comparable therapeutic effects with CD19-targeting CAR-T cells in solid tumors. To overcome this challenge, scientists have developed several methods to optimize the structure of CARs, including coexpression of a transcription factor called c-Jun in CAR-T cells. The authors previously developed a novel multiple-chain DAP-CAR that shows promising solid tumor eradication capacity. In this study, overexpression of c-Jun only slightly improved the antitumor activity of DAP-CAR-T cells, suggesting other optimization methods are needed.

Novel two-chain structure utilizing KIRS2/DAP12 domain improves the safety and efficacy of CAR-T cells in adults with r/r B-ALL.

Engineered T cells that express chimeric antigen receptors (CARs) have been a promising therapy for hematologic malignancies. The optimization of CAR structure using different signaling domains can alter a wide range of CAR-T cell properties, including anti-tumor activity, long-term persistence, and safety. In this study, we developed a novel CAR structure based on KIRS2/Dap12 for B cell acute lymphoblastic leukemia (B-ALL) antigen CD19 and compared the anti-tumor efficacy and safety of this construct in transduced T cells with standard second-generation CAR-T cells targeting CD19 for B-ALL in vitro and in vivo and in adult relapsed/refractory (r/r) B-ALL patients. We discovered that KIRS2/Dap12 receptor infused with 4-1BB co-stimulation domain could enhance anti-tumor efficacy by remarkably increasing the production of pro-inflammatory interleukin-2 (IL-2), especially when co-cultured with antigen-positive tumor cells. In addition, CD19-KIRS2/Dap12-BB CAR-T cells showed the inspiring outcome that complete responses were seen in 4 of 4 (100%) patients without neurotoxicity and a high rate of severe cytokine release syndrome (CRS) after CAR-T infusion in a phase I clinical trial. Given these encouraging findings, CD19-KIRS2/Dap12-BB CAR-T cells are safe and can lead to clinical responses in adult patients with r/r B-ALL, indicating that further assessment of this therapy is warranted.

Role of CXCR4 as a Prognostic Biomarker Associated With the Tumor Immune Microenvironment in Gastric Cancer.

Background: Gastric cancer (GC) is a leading cause of cancer-related deaths worldwide, accounting for high rates of morbidity and mortality in the population. The tumor microenvironment (TME), which plays a crucial role in GC progression, may serve as an optimal prognostic predictor of GC. In this study, we identified CXC motif chemokine receptor 4 (CXCR4) as a TME-related gene among thousands of differentially expressed genes (DEGs). We showed that CXCR4 can be used to predict the effect of immunotherapy in patients with GC. Methods: GC samples obtained from The Cancer Genome Atlas (TCGA) were analyzed for the presence of stroma (stromal score), the infiltration of immune cells (immune score) in tumor tissues, and the tumor purity (estimate score) using the ESTIMATE (Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data) algorithm. DEGs were sorted based on differences in the values of the three scores. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to determine the biological processes and pathways enriched in these DEGs. The correlations of scores with clinicopathological features and overall survival (OS) of patients with GC were assessed by the Kaplan-Meier survival and Cox regression analyses. Through subsequent protein-protein interaction (PPI) network and univariate Cox regression analyses, CXCR4 was identified as a TME-related gene. Gene Set Enrichment Analysis (GSEA) was performed to assess the role of CXCR4 in the TME of GC. The CIBERSORT algorithm was used to further explore the correlation between tumor-infiltrating immune cells (TIICs) and CXCR4. Finally, the TISIDB database was used to predict the efficacy of immunotherapy in patients with GC. Results: We extracted 1231 TME-related DEGs and by an overlapping screening of PPI network and univariate Cox regression, CXCR4 was identified as a biomarker of TME, which deeply engaged in immune-related biological processes of gastric cancer and have close association with several immunocompetent cells. Conclusion: CXCR4 may be a useful biomarker of prognosis and an indicator of the TME in GC.

Establishment of a Novel Risk Score System of Immune Genes Associated With Prognosis in Esophageal Carcinoma.

BACKGROUND: Few studies have addressed the role of immune-related genes in the survival and prognosis of different esophageal cancer (EC) sub-types. We established two new prognostic model indexes by bioinformatics analysis to select patients with esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC) who may benefit from immunotherapy. METHODS: Based on TCGA and ImmPort data sets, we screened immune genes differentially expressed between tumor and normal tissues in ESCC and EAC and analyzed the relationship between these genes and patient survival outcomes. We established the risk score models of immune-related genes in ESCC and EAC by multivariate COX regression analysis. RESULTS: We identified 12 and 11 immune-related differentially expressed genes associated with the clinical prognosis of ESCC and EAC respectively, based on which two prognostic risk score models of the two EC sub-types were constructed. It was found that the survival probability of patients with high scores was significantly lower than that of patients with low scores (p < 0.001). BMP1, EGFR, S100A12, HLA-B, TNFSF18, IL1B, MAPT and OXTR were significantly related to sex, TNM stage or survival outcomes of ESCC or EAC patients (p < 0.05). In addition, the risk score of ESCC was significantly correlated with the level of B cell infiltration in immune cells (p < 0.05). CONCLUSIONS: The prognosis-related immune gene model indexes described herein prove to be useful prognostic biomarkers of the two EC sub-types in that they may provide a reference direction for looking for the beneficiaries of immunotherapy for EC patients.

KLF5-Modulated lncRNA NEAT1 Contributes to Tumorigenesis by Acting as a Scaffold for BRG1 to Silence GADD45A in Gastric Cancer.

Long noncoding RNAs (lncRNAs), genomic "dark matter," are deeply involved in diverse biological processes. The lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) is a highly participatory lncRNA; however, its roles in gastric cancer (GC) remain largely unexplored. Here, we demonstrated that the expression of NEAT1 was significantly increased and negatively correlated with prognosis in GC. Subsequent experiments confirmed that KLF5 can induce NEAT1 expression by binding to the NEAT1 promoter region. Further experiments revealed that NEAT1 silencing significantly suppressed cell proliferation both in vitro and in vivo and induced apoptosis. We used mRNA sequencing (mRNA-seq) to identify the preferentially affected genes linked to cell proliferation in cells with NEAT1 knockdown. Mechanistically, NEAT1 bound BRG1 (SMARCA4) directly, modulating H3K27me3 and H3K4me3 in the GADD45A promoter to regulate GADD45A-dependent G2/M cell cycle progression. In addition, BRG1 was significantly upregulated and correlated with outcomes in GC; moreover, it promoted cell proliferation both in vitro and in vivo. Taken together, our data support the importance of NEAT1 in promoting GC tumorigenesis and indicate that NEAT1 might be a diagnostic and therapeutic target in GC.

LINC00675 Suppresses Cell Proliferation and Migration via Downregulating the H3K4me2 Level at the SPRY4 Promoter in Gastric Cancer.

Accumulating evidence indicates that long noncoding RNAs (lncRNAs) are dysregulated in diverse tumors and take a pivotal role in modulating biological processes. In our study, a decreased expression level of LINC00675 in gastric cancer (GC) was first determined by data from The Cancer Genome Atlas (TCGA) and was identified using specimens from GC patients. Then, in vitro and in vivo functional experiments elaborated that LINC00675 could suppress cell proliferation and migration in GC. Multiple differentially expressed genes (DEGs) in LINC00675-overexpressing cells were identified through RNA sequencing analysis. An RNA-binding protein immunoprecipitation (RIP) assay was conducted to reveal that LINC00675 competitively bound with lysine-specific demethylase 1 (LSD1). A coimmunoprecipitation (coIP) assay indicated that LINC00675 overexpression may strengthen the binding of LSD1 and H3K4me2, whereas the chromatin immunoprecipitation (ChIP) assay results verified lower expression of H3K4me2 at the sprouty homolog 4 (SPRY4) promoter region. Together, our research identified that LINC00675 was remarkably downregulated in GC tissues and cells relative to nontumor tissues and cells. LINC00675 could repress GC tumorigenesis and metastasis via competitively binding with LSD1 and intensifying the binding of LSD1 and its target H3K4me2. Importantly, this contributed to attenuated binding of H3K4me2 at the promoter region of oncogene SPRY4 and suppressed SPRY4 transcription, thus suppressing GC cell proliferation and migration.

Exosomal circSHKBP1 promotes gastric cancer progression via regulating the miR-582-3p/HUR/VEGF axis and suppressing HSP90 degradation.

BACKGROUND: Circular RNAs (circRNAs) play important regulatory roles in the development of various cancers. However, biological functions and the underlying molecular mechanism of circRNAs in gastric cancer (GC) remain obscure. METHODS: Differentially expressed circRNAs were identified by RNA sequencing. The biological functions of circSHKBP1 in GC were investigated by a series of in vitro and in vivo experiments. The expression of circSHKBP1 was evaluated using quantitative real-time PCR and RNA in situ hybridization, and the molecular mechanism of circSHKBP1 was demonstrated by western blot, RNA pulldown, RNA immunoprecipitation, luciferase assays and rescue experiments. Lastly, mouse xenograft and bioluminescence imaging were used to exam the clinical relevance of circSHKBP1 in vivo. RESULTS: Increased expression of circSHKBP1(hsa_circ_0000936) was revealed in GC tissues and serum and was related to advanced TNM stage and poor survival. The level of exosomal circSHKBP1 significantly decreased after gastrectomy. Overexpression of circSHKBP1 promoted GC cell proliferation, migration, invasion and angiogenesis in vitro and in vivo, while suppression of circSHKBP1 plays the opposite role. Exosomes with upregulated circSHKBP1 promoted cocultured cells growth. Mechanistically, circSHKBP1 sponged miR-582-3p to increase HUR expression, enhancing VEGF mRNA stability. Moreover, circSHKBP1 directly bound to HSP90 and obstructed the interaction of STUB1 with HSP90, inhibiting the ubiquitination of HSP90, resulting in accelerated GC development in vitro and in vivo. CONCLUSION: Our findings demonstrate that exosomal circSHKBP1 regulates the miR-582-3p/HUR/VEGF pathway, suppresses HSP90 degradation, and promotes GC progression. circSHKBP1 is a promising circulating biomarker for GC diagnosis and prognosis and an exceptional candidate for further therapeutic exploration.

TEAD4 modulated LncRNA MNX1-AS1 contributes to gastric cancer progression partly through suppressing BTG2 and activating BCL2.

BACKGROUND: Gastric cancer (GC) is the third leading cause of cancer-related mortality globally. Long noncoding RNAs (lncRNAs) are dysregulated in obvious malignancies including GC and exploring the regulatory mechanisms underlying their expression is an attractive research area. However, these molecular mechanisms require further clarification, especially upstream mechanisms. METHODS: LncRNA MNX1-AS1 expression in GC tissue samples was investigated via microarray analysis and further determined in a cohort of GC tissues via quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. Cell proliferation and flow cytometry assays were performed to confirm the roles of MNX1-AS1 in GC proliferation, cell cycle regulation, and apoptosis. The influence of MNX1-AS1 on GC cell migration and invasion was explored with Transwell assays. A xenograft tumour model was established to verify the effects of MNX1-AS1 on in vivo tumourigenesis. The TEAD4-involved upstream regulatory mechanism of MNX1-AS1 was explored through ChIP and luciferase reporter assays. The mechanistic model of MNX1-AS1 in regulating gene expression was further detected by subcellular fractionation, FISH, RIP, ChIP and luciferase reporter assays. RESULTS: It was found that MNX1-AS1 displayed obvious upregulation in GC tissue samples and cell lines, and ectopic expression of MNX1-AS1 predicted poor clinical outcomes for patients with GC. Overexpressed MNX1-AS1 expression promoted proliferation, migration and invasion of GC cells markedly, whereas decreased MNX1-AS1 expression elicited the opposite effects. Consistent with the in vitro results, MNX1-AS1 depletion effectively inhibited the growth of xenograft tumour in vivo. Mechanistically, TEAD4 directly bound the promoter region of MNX1-AS1 and stimulated the transcription of MNX1-AS1. Furthermore, MNX1-AS1 can sponge miR-6785-5p to upregulate the expression of BCL2 in GC cells. Meanwhile, MNX1-AS1 suppressed the transcription of BTG2 by recruiting polycomb repressive complex 2 to BTG2 promoter regions. CONCLUSIONS: Our findings demonstrate that MNX1-AS1 may be able to serve as a prognostic indicator in GC patients and that TEAD4-activatd MNX1-AS1 can promote GC progression through EZH2/BTG2 and miR-6785-5p/BCL2 axes, implicating it as a novel and potent target for the treatment of GC.

CircRNAs in cancer metabolism: a review.

Altered energy metabolism is a hallmark of tumors aiming at supplying necessary nutrients for tumorigenesis and development. These redirected metabolic pathways associated with carbohydrate, lipid and amino acid are orchestrated not only by carcinogenic proteins but by non-coding RNAs. Among them, circular RNA (circRNA), as a kind of novel identified non-coding RNAs, has become the focus of attention. Through binding with corresponding microRNAs or directly contacting proteins, circRNA plays a primarily important role in regulating cellular metabolism. Herein, we analyze the emerging findings and select circRNAs contributing to mutant glycolysis, lipogenesis and lipolysis, glutam inolysis, and oxidative respiration to deepen the understanding about the cancer metabolic regulatory network. In addition, we also discuss the possibility of circRNAs exerting their functions via exosomes and cancer stem cells. Owing to their unique structures and wide impacts, circRNAs may help reap huge fruits in developing clinical treatments targeting cancer metabolism.

KLF5 and MYC modulated LINC00346 contributes to gastric cancer progression through acting as a competing endogeous RNA and indicates poor outcome.

It was found in this study that long intergenic non-protein coding RNA 346 (LINC00346) was an lncRNA aberrantly expressed in gastric cancer (GC) based on multiple Gene Expression Omnibus (GEO) databases of GC cohorts. The LINC00346 gene was recurrently amplified and upregulated in GC, and its expression was positively correlated with poor pathologic stage, large tumor size, and poor prognosis. In addition, the oncogenic transcription factors KLF5 and MYC could bind to the LINC00346 promoter and enhance its expression. Gene Set Enrichment Analysis (GSEA) in the GEO datasets revealed that cell cycle and focal adhesion genes were enriched in patients with high LINC00346 expression. In vitro and in vivo assays of LINC00346 alterations revealed a complex integrated phenotype affecting cell growth, migration and invasion. Strikingly, high-throughput sequencing analysis after LINC00346 alterations highlighted alterations in cell cycle and focal adhesion pathways in GC cells. Mechanistically, argonaute 2 (Ago2) was recruited by LINC00346, which functioned as a molecular sponge for miR-34a-5p by antagonizing its ability to repress CD44, NOTCH1, and AXL protein translation. Taken together, our findings support a model in which the KLF5, MYC/LINC00346/miR-34a-5p cross-talk served as critical effectors in GC tumorigenesis and progression, suggesting a new therapeutic direction in the treatment of GC.