Colorectal Cancer Cell Differentiation Is Dependent on the Repression of Aerobic Glycolysis by NDRG2-TXNIP Axis.

BACKGROUND: Poorly differentiated colorectal cancers are more aggressive. Metabolism reprogramming is a significant hallmark in cancer, and aerobic glycolysis is common. However, how cancer cells reprogramming glucose metabolism contributes to cell differentiation was largely unknown. Previous studies have reported that tumor suppressor NDRG2 could promote colorectal cancers differentiation. AIMS: This study aims to demonstrate that NDRG2 promotes the differentiation of colorectal cancers, potentially through the inhibition of aerobic glycolysis via TXNIP induction. METHODS: Western blotting, qRT-PCR and immunohistochemical staining were used to detect the expression of related molecules. MTT assay was used to reflect cell viability and proliferation. Immunofluorescent assay was performed to identify the expression and distribution of molecules. Luciferase analysis and CHIP assays were used to investigate the mechanism. Bioinformatic analysis was performed to predict the relevance. RESULTS: In colorectal cancers, NDRG2 could inhibit cell proliferation, reduce glucose uptake and decrease expression of key glycolysis enzymes. Upregulated NDRG2 is associated with differentiated cancer. However, deletion of TXNIP, a classic glucose metabolism inhibitor, could obviously alter the function of NDRG2 in differentiation, glucose uptake, expression of key glycolysis enzymes and proliferation. Mechanistically, high glucose flux promotes the activity of TXNIP promoter. And NDRG2 promotes the occupancy of transcription factor Mondo A on TXNIP promoter, predominantly through the suppression of c-myc, which could complete with Mondo A binding to TXNIP promoter. In clinical samples, high expression of TXNIP indicates good prognosis and outcome. CONCLUSIONS: NDRG2-dependent induction of TXNIP is critical for the aerobic glycolysis during colorectal cancers differentiation.

The differentiation of colorectal cancer is closely relevant to m6A modification.

The occurrence and development of tumors cannot be separated from the influence of differentiation at different stages and levels. Our study found that E-cadherin was significantly increased in cell model induced by sodium butyrate and cell density, while METTL3, METTL16 and WTAP were decreased during the differentiation of cells. In the clinicopathological tissues, E-cadherin was low expressed in poorly differentiated tumor tissues and above three regulators were highly expressed in poorly differentiated tissues. At the levels of clinicopathological differentiation, tissue differentiation and cell differentiation, the result indicated that the poor prognosis of colorectal cancer (CRC) may be closely related to high expression of total m6A level and high expression of METTL3, METTL16 and WTAP.

A new endoscopic technique for specific gastrointestinal stromal tumors: a retrospective cohort study.

OBJECTIVES: Surgical resection is recommended for treating gastrointestinal stromal tumors (GISTs) >20 mm. With the emergence of minimally invasive concept, endoscopic techniques are involved. We introduce a new endoscopic technique termed as endoscopic submucosal resection preserving serosa (ESR-PS) for GISTs ≥ 20 mm with mucosal erosion or ulcer locating at deep muscularis propria. METHODS: This retrospective cohort study collected patients at the endoscopy center of the First Affiliated Hospital of Xi'an Jiaotong University between January 2019 and 2021. The primary outcome was adverse events including pneumoperitoneum, fever and delayed bleeding. The second outcomes included en bloc resection complete en bloc resection, recurrence, operation time, hospital stay time after ESR-PS, postoperative indwelling gastric tube and postoperative eating. RESULTS: A total of 49 patients were included. One patient experienced pneumoperitoneum. All patients did not experienced fever or delayed bleeding after ESR-PS. All cases achieved en bloc resection and complete en bloc resection. The median operation time of ESR-PS was 49 min (range 43-71). The indwelling gastric tubes were given to patients for 1 d or 2 d after ESR-PS. After 1 d or 2 d, patients started oral diet, staying in hospital for a median of 4 (3-4) d after ESR-PS. During the follow-up time, recurrence was not found. CONCLUSIONS: Our study indicated that ESR-PS is a feasible, effective and safe technique for GISTs ≥ 20mm with mucosal erosion or ulcer locating at deep muscularis propria. More large, multi-center and prospective studies are needed to evaluate the effectiveness and safety of ESR-PS in the future.

The Effect of Helicobacter pylori Eradication in Patients with Gastroesophageal Reflux Disease: A Meta-Analysis of Randomized Controlled Studies.

AIM: Helicobacter pylori infection has been established as a definite risk factor for gastric cancer. However, the consequence of H. pylori eradication on the progression of gastroesophageal reflux disease (GERD) remains controversial. The purpose of our study was to investigate the relationship between H. pylori eradication and the development of GERD. METHODS: A comprehensive, English literature search was performed from January 1990 to April 2019. Only randomized controlled trials (RCT) that evaluated the effect of H. pylori eradication on GERD were included. Meta-analysis of pooled OR was performed using Review Manger 5.1.7. RESULTS: Seventeen articles with 6,889 subjects (intention-to-treat) that fulfilled the inclusion criteria were finally included in the analysis. Of them, 8 RCTs have the similar study design and inclusion criterion, which included patients with H. pylori infection but without GERD at baseline. The OR for the development of erosive GERD after H. pylori eradication was 1.67 (95% CI 1.12-2.48, p = 0.01). The OR for the development of GERD-related symptoms after H. pylori eradication in eradication group compared with control group was 1.04 (95% CI 0.84-1.29, p = 0.71). In addition, 9 RCTs included patients with both baseline H. pylori infection and GERD. The OR for the healing rates and relapse rates after H. pylori eradication in the H. pylori eradication group vs. control group was 0.92 (95% CI 0.47-1.82, p = 0.82) and 1.12 (95% CI 0.60-2.09, p = 0.71), respectively. CONCLUSIONS: Our meta-analyses showed H. pylori eradication may lead to the development of new erosive GERD. However, eradication of H. pylori may affect neither the healing rates nor relapse rates of preexisting GERD.

Long noncoding RNA NNT-AS1 promotes gastric cancer proliferation and invasion by regulating microRNA-363 expression.

Increasing studies showed that long noncoding RNAs (lncRNAs) had crucial regulatory roles in various tumors, including gastric cancer (GC). Recent studies demonstrated that lncRNA nicotinamide nucleotide transhydrogenase-antisense RNA1 (NNT-AS1) played an important role in several tumors. However, the role and expression of NNT-AS1 in GC progression remain unknown. In our study, we indicated that NNT-AS1 expression was upregulated in GC samples compared with the nontumor tissues. We also showed that NNT-AS1 expression was upregulated in the GC cell lines. Ectopic expression of NNT-AS1 promoted GC cell line HGC-27 cell proliferation, cell cycle progression, and invasion. In addition, we showed that NNT-AS1 acted as a sponge competing endogenous RNA for microRNA-363 (miR-363), which was downregulated in the GC samples and cell lines. miR-363 expression was negatively related with NNT-AS1 expression in GC samples. Upregulated expression of miR-363 suppressed GC cell growth, cycle, and invasion. Furthermore, we reported that elevated expression of NNT-AS1 promoted GC cell proliferation, cycle, and invasion partly by suppressing miR-363 expression. These results indicated that lncRNA NNT-AS1 acted as an oncogene in the development of GC partly by inhibiting miR-363 expression.

c-Myc-driven glycolysis via TXNIP suppression is dependent on glutaminase-MondoA axis in prostate cancer.

Oncogenic c-Myc-induced metabolic reprogramming triggers cellular dependency on exogenous glucose and glutamine. Understanding how nutrients are used may provide new target for therapeutic intervention. We previously provided an alternate route to c-Myc-driven glucose metabolism via the repression of thioredoxin-interacting protein (TXNIP), which is a potent negative regulator of glucose uptake. Herein, we demonstrate that c-Myc suppression of TXNIP is predominantly through the activation of glutaminolysis via glutaminase (GLS1) in prostate cancer cells. Glutamine depletion blocked c-Myc-dependent reductions of TXNIP and its principal regulator MondoA transcriptional activity. Further, GLS1 inhibition by either siRNA or CB-839 resumed TXNIP expression that was repressed by c-Myc. The TXNIP promoter with mutant E-Box region, which was recognized by MondoA, failed to respond to c-Myc or GLS1, indicating c-Myc repression of TXNIP by GLS1 is predominantly through the blockage of MondoA activity. Especially, ectopic TXNIP expression decreased c-Myc-induce glucose uptake and lead to a broad range of glycolytic target gene suppressions. Thus TXNIP is a key adaptor for c-Myc-driven aerobic glycolysis. Supporting the biological significance of c-Myc and TXNIP, their reciprocal relationship are correlates with patient outcome and contributes to the aggressive phenotype in PCAs.

LncRNA SNHG5 promotes the proliferation and cancer stem cell-like properties of HCC by regulating UPF1 and Wnt-signaling pathway.

The role of long noncoding RNA (lncRNAs) had been demonstrated in different types of cancer, including hepatocellular carcinoma. This study was intended to investigate the role of lncRNA small nucleolar RNA host gene 5 (SNHG5) in HCC proliferation and the liver CSC-like properties. Through functional experiments, we determined that knockdown of SNHG5 repressed HCC cell proliferation and CSC-like properties, while over-expression of SNHG5 promoted cell growth. At the same time, CSC markers (CD44, CD133, and ALDH1) and related transcription factors (OCT4, SOX2, and NANOG) were downregulated when SNHG5 was knocked down. Mechanically, RNA immunoprecipitation (RIP) and RNA pulldown assay showed that SNHG5 regulated the proliferation and CSC-like properties of HCC by binding UPF1. Further investigations showed that expression of critical components of Wnt/ß-catenin pathway (ß-catenin, TCF4, c-myc, cyclinD1, and c-Jun) were upregulated with depletion of UPF1 in liver CSCs, which were downregulated with depletion of SNHG5. After use of the inhibitor of Wnt/ß-catenin pathway, the formation of liver CSCs sphere decreased. Taken together, SNHG5 plays a critical role to promote HCC cell proliferation and cancer stem cell-like properties via UPF1 and Wnt/ß-catenin pathway.

NDRG2 ablation reprograms metastatic cancer cells towards glutamine dependence via the induction of ASCT2.

Background: Metastasis is the most common cause of lethal outcome in various types of cancers. Although the cell proliferation related metabolism rewiring has been well characterized, less is known about the association of metabolic changes with tumor metastasis. Herein, we demonstrate that metastatic tumor obtained a mesenchymal phenotype, which is obtained by the loss of tumor suppressor NDRG2 triggered metabolic switch to glutamine metabolism. Methods: mRNA-seq and gene expression profile analysis were performed to define the differential gene expressions in primary MEC1 and metastatic MC3 cells and the downstream pathways of NDRG2. NDRG2 regulation of Fbw7-dependent c-Myc stability were determined by immunoprecipitation and protein half-life assay. Luciferase reporter and ChIP assays were used to determine the roles of Akt and c-Myc in mediating NDRG2-dependent regulation of ASCT2 in in both tumor and NDRG2-knockout MEF cells. Finally, the effect of the NDRG2/Akt/c-Myc/ASCT2 signaling on glutaminolysis and tumor metastasis were evaluated by functional experiments and clinical samples. Results: Based on the gene expression profile analysis, we identified metastatic tumor cells acquired the mesenchymal-like characteristics and displayed the increased dependency on glutamine utilization. Further, the gain of NDRG2 function blocked epithelial-mesenchymal transition (EMT) and glutaminolysis, potentially through suppression of glutamine transporter ASCT2 expression. The ASCT2 restoration reversed NDRG2 inhibitory effect on EMT program and tumor metastasis. Mechanistic study indicates that NDRG2 promoted Fbw7-dependent c-Myc degradation by inhibiting Akt activation, and subsequently decreased c-Myc-mediated ASCT2 transcription, in both tumor and NDRG2-knockout MEF cells. Supporting the biological significance, the reciprocal relationship between NDRG2 and ASCT2 were observed in multiple types of tumor tissues, and associated with tumor malignancy. Conclusions: NDRG2-dependent repression of ASCT2 presumably is the predominant route by which NDRG2 rewires glutaminolysis and blocks metastatic tumor survival. Targeting glutaminolytic pathway may provide a new strategy for the treatment of metastatic tumors.

The Comparison between Endoscopic Submucosal Dissection and Surgery in Gastric Cancer: A Systematic Review and Meta-Analysis.

AIMS: There are two treatment modalities for early gastric cancer (EGC)-surgery and endoscopic submucosal dissection (ESD). We aimed to compare the safety and efficacy of ESD with surgery. METHOD: The article was performed by searching PubMed databases. Data were extracted using predefined form and odds ratios (OR) with 95% confidence intervals (CI) calculated and P value. RESULTS: 13 studies were identified. The incidence of perforation in two groups was different [OR = 6.18 (95% CI: 1.37-27.98), P = 0.02]. The prevalences of synchronous and metachronous cancer in the ESD group were higher than those in the surgery group [OR = 8.52 (95% CI: 1.99-36.56), P = 0.004 and OR = 7.15 (95% CI: 2.95-17.32), P < 0.0001]. The recurrence and complete resection rates were different [OR = 6.93 (95% CI: 2.83-16.96), P < 0.0001 and OR = 0.32 (95% CI: 0.20-0.52), P < 0.00001]. Compared with the surgery group, the hospital stay was shorter [IV = -7.15 (95% CI: -9.08-5.22), P < 0.00001], the adverse event rate was lower, and the quality of life (QOL) was better in the ESD group. The difference of bleeding was not found. CONCLUSION: ESD appears to be preferable for EGC, due to a lower rate of adverse events, shorter hospital stay, cheaper cost, and higher QOL.

NDRG2 facilitates colorectal cancer differentiation through the regulation of Skp2-p21/p27 axis.

Poorly differentiated colorectal cancers (CRCs) are more aggressive and lack targeted therapies. We and others previously reported the predominant role of tumor-suppressor NDRG2 in promoting CRC differentiation, but the underlying mechanism is largely unknown. Herein, we demonstrate that NDRG2 induction of CRC cell differentiation is dependent on the repression of E3 ligase Skp2 activity. In patients and Ndrg2 knockout mice, NDRG2 and Skp2 are negatively correlated and associated with cell differentiation stage. Further, NDRG2 suppression of Skp2 contributes to the inductions and stabilizations of p21 and p27, which are Skp2 target proteins for degradation. The reduction of either p21 or p27 levels by shRNA can decrease NDRG2-induced AKP activity and resume cell growth inhibition, thus both p21 and p27 are required for NDRG2 effect on the promotion of cell differentiation in CRCs. The mechanistic study shows that NDRG2 suppresses ß-catenin nuclear translocation and decreases the occupancy of ß-catenin/TCF complex on Skp2 promoter, potentially through dephosphorylating GSK-3ß. By subjecting a series of NDRG2 deletion mutants to Skp2 expression, the loss of NH2-terminal domain can completely abolish NDRG2-dependent differentiation induction. Supporting the biological significance of the reciprocal relationship between NDRG2 and Skp2, an NDRG2low/Skp2high gene expression signature correlates with poor CRC patient outcome and could be considered as a diagnostic marker of CRCs.

MicroRNA-26a inhibits proliferation and metastasis of human hepatocellular carcinoma by regulating DNMT3B-MEG3 axis.

miR-26a is known to play an important oncosuppressive role in HCC. However, its regulatory role and relationship with other non-coding RNAs is less clear. In the present study, we report that the expression levels of miR-26a and long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3) were frequently downregulated in HCC tissues compared to matched non-malignant tissues. In addition, the expression levels of miR-26a and MEG3 were negatively correlated with the tumor sizes and TNM clinical stage in HCC patients. Overexpression of miR-26a significantly reduced the capacity of proliferation, invasion and migration of HCC cells. Moreover, we demonstrated that DNA methyltransferase 3b (DNMT3B) was a direct target gene of miR-26a. Overexpression of miR-26a suppressed the expression level of DNMT3B. Inhibited expression of DNMT3B showed similar tumor suppressive effects induced by miR-26a upregulation, and resulted in the upregulation of MEG3. Furthermore, we found that the expression levels of DNMT3B were upregulated in the HCC tissues compared with non-malignant tissues, and it was inversely correlated with miR-26a and MEG3 in HCC tissues. Thus, these results provided a plausible link between the observed reduction of miR-26a and MEG3 in HCCs. Together, the present study added miR-26a/DNMT3B/MEG3 axis to the complex mechanisms of HCC development.