Comprehensive Analysis of Differentially Expressed Profiles of mRNA N6-Methyladenosine in Colorectal Cancer.

Aim: To comprehensively profile the landscape of the mRNA N6-methyladenosine (m6A) modification in human colorectal cancer (CRC). Methods: Methylated RNA immunoprecipitation sequencing (MeRIP-seq) was explored to compare the difference in mRNA N6-methyladenosine (m6A) methylation between CRC tissues and adjacent normal control (NC) tissue. RNA-sequencing (RNA-seq) was performed to transcribe differentially expressed mRNAs. Conjoint analysis of MeRIP-seq and RNA-seq data was conducted to predict RNA-binding proteins (RBPs). Results: MeRIP-seq identified 1110 differentially m6A methylated sites (DMMSs) and 980 differentially m6A methylated genes (DMMGs) in CRC, with 50.13% of all modified genes showing unique m6A-modified peaks in CRC. RNA-seq showed 915 upregulated genes and 1463 downregulated genes in CRC. QRT-PCR verified the RNA-seq results by detecting the expression of some mRNAs. Conjoint analysis of MeRIP-seq and RNA-seq identified 400 differentially m6A methylated and expressed genes (DEGs), and pathway analysis detected that DMMGs and DEGs were closely related to cancer. After analyzing these DMMGs and DEGs through the GEPIA database, we found that the expression of B3GNT6, DKC1, SRPK1, and RIMKLB were associated with prognosis, and the expression of B3GNT6 and RIMKLB were associated with clinical stage. 17 RBPs were identified based on the DMMGs and DEGs, among which FXR1, FXR2, FMR1, IGF2BP2, IGF2BP3, and SRSF1 were obviously highly expressed in CRC, and FMR1, IGF2BP2, and IGF2BP3 were closely related to methylation, and might be involved in the development of CRC. Conclusion: This study comprehensively profiled m6A modification of mRNAs in CRC, which revealed possible mechanisms of m6A-mediated gene expression regulation.

hTERT promotes gastric intestinal metaplasia by upregulating CDX2 via NF-κB signaling pathway.

BACKGROUND: hTERT has been reported involved in the proliferation and metastasis of gastric cancer, but the role of hTERT in gastric intestinal metaplasia, a premalignant lesion of the gastric mucosa was unknown. The aim of the present study was to investigate the role of hTERT in GIM and the effect of hTERT on CDX2 expression in gastric cells. RESULTS: Experiments showed that expression of hTERT was significantly higher in GIM than in normal gastric mucosa. Moreover, hTERT increased the KLF4 level via NF-κB during GIM. Furthermore, KLF4 is involved in the up-regulation of CDX2 induced by hTERT, and hTERT can interact with p50, thereby increasing the level of CDX2. MATERIALS AND METHODS: Immunohistochemistry was used to detect the expression of hTERT in gastric intestinal metaplasia tissue. Then, effect of hTERT on the expression of CDX2 was detected by qRT-PCR, WB and dual luciferase experiment. The role of p65 and p50 in the regulation of CDX2 were further detected by WB, CO-IP and ChIP. CONCLUSIONS: We may conclude that hTERT promotes GIM by up-regulating CDX2 via NF-κB signaling pathway.

The FOXM1-induced resistance to oxaliplatin is partially mediated by its novel target gene Mcl-1 in gastric cancer cells.

Myeloid cell leukemia-1 (Mcl-1) is an anti-apoptotic protein that belongs to the Bcl-2 family. The aberrant expression of Mcl-1 is important for sensitivity to chemotherapy drugs in gastric cancer. However, the regulatory mechanism of Mcl-1 in gastric cancer cells remains unclear. In this study, we first found that Forkhead box M1 (FOXM1) and Mcl-1 expression levels were positively correlated in human gastric cancer specimens and that both are associated with poor prognosis of patients treated with oxaliplatin. Second, we demonstrated that the expression level of Mcl-1 was correlated with FOXM1 expression in gastric cancer cells. Third, reporter assays showed that FOXM1 upregulated the promoter activity of the Mcl-1 gene. Electrophoretic mobility shift assays (EMSA) and chromatin immunoprecipitation (ChIP) assays further demonstrated that FOXM1 could bind to a particular site (-635acaaacaa-628) in the promoter region of the Mcl-1 gene. Moreover, CCK-8 assays and analyses of apoptosis revealed that the suppression of the FOXM1/Mcl-1 pathway induced apoptosis and thus increased sensitivity to oxaliplatin in gastric cancer cells, whereas the enhancement of the FOXM1/Mcl-1 pathway inhibited apoptosis and decreased sensitivity to oxaliplatin in gastric cancer cells. Taken together, this study is the first to not only show that Mcl-1 is a novel target gene of FOXM1 but also suggest that targeting FOXM1/Mcl-1 may be a novel strategy to enhance sensitivity to oxaliplatin in gastric cancer.

PLCE1 polymorphism and upper gastrointestinal cancer risk: a meta-analysis.

BACKGROUND: In recent years, the PLCE1 rs2274223 polymorphism has been extensively investigated as a potential risk factor for upper gastrointestinal cancers, including squamous cell carcinoma (ESCC) and gastric cancer. However, the results of these studies have been inconsistent. METHODS: A meta-analysis of 13 case-control studies was performed including more than 11,000 subjects with genotyped PLCE1 rs2274223 polymorphisms. Odds ratios (OR) with 95% confidence intervals (CI) were employed to assess the association of the PLCE1 rs2274223 polymorphism with a susceptibility to ESCC or gastric cancer. RESULTS: A statistically significant increase in the risk of ESCC was associated with the PLCE1 rs2274223 polymorphism. This included the homozygous genetic model (OR = 1.46), heterozygous genetic model (OR = 1.25) and allelic genetic model (OR = 1.23). Similar results were consistently found for gastric cancer. In a subgroup analysis, the PLCE1 rs2274223 polymorphism was found to be a very sensitive marker for gastric cardia cancer as shown by the homozygous genetic model (OR = 2.23), heterozygous genetic model(OR = 1.59) and allelic genetic model (OR = 1.47). The risk associations of all of the gastric cardia cancer models were statistically significant. In contrast, none of the genetic models for non-cardia gastric cancer were significant. CONCLUSIONS: In this meta-analysis, the PLCE1 rs2274223 polymorphism was confirmed to have a statistically significant association with an increasing risk of ESCC and gastric cancer. The increase risk was especially observed for gastric cardia cancer.

[Efficacy and safety of different dosages of intravesical epirubicin instillation for prevention of primary superficial bladder carcinoma from recurrence].

OBJECTIVE: To investigate the efficiency and safety of different regimens by intravesical instillation of epirubicin, a derivative of adriamycin, for the prevention of primary superficial bladder carcinoma from recurrence. METHODS: Ninety patients supplemented with intravesical epirubicin instillation after operation were randomly divided into three groups: Group A--80 mg in one dose; Group B--repeated epirubicin 40 mg q wk x 4-8 sessions followed by q month to the end of the second year; or Group C--50 mg q month to the same duration. All patients were followed up for two years by observing the recurrence rates and side effects. RESULTS: The recurrence rate of groups A, B and C at one year was 16.7%, 13.3% and 16.7%, respectively, without any significant difference observed. However, it was 50.0%, 36.7% and 36.7% at two years, at which time the recurrence rate of group A was significantly higher than those of groups B and C. The side effects rate was 23.3%, 40.0% and 33.3% for groups A, B and C, respectively. The more instillations the patients had, the more severe side effects were. CONCLUSION: Early postoperative single high dose intravesical instillation of epirubicin combined with repeated lower doses of the same drug every month may be an efficient and safe regimen to prevent the primary superficial bladder carcinoma from recurrence.