METTL14 promotes the development of diabetic kidney disease by regulating m6A modification of TUG1.

BACKGROUND: Diabetic kidney disease (DKD) is one of the most common diabetic complications. Endoplasmic reticulum stress (ERS) is an important step for renal tubular epithelial cell apoptosis during DKD progression. Herein, the role and regulatory mechanism of METTL14 in ERS during DKD progression were investigated. METHODS: DKD animal and cell models were established by streptozotocin (STZ) and high glucose (HG), respectively. HE and Masson staining were performed to analyze renal lesions in DKD mouse. Cell viability and proliferation were determined by MTT and EdU staining, respectively. HK2 cell apoptosis was analyzed by flow cytometry. TUG1 m6A level was determined by Me-RIP. The interaction between TUG1, LIN28B and MAPK1 was analyzed by RIP and RNA pull-down assays. RESULTS: HG stimulation promoted apoptosis and increased ERS marker proteins (GRP78, CHOP and caspase12) expression in HK2 cells, while these changes were reversed by METTL14 knockdown. METTL14 inhibited TUG1 stability and expression level in an m6A-dependent manner. As expected, TUG1 knockdown abrogated METTL14 knockdown's inhibition on HG-induced HK2 cell apoptosis and ERS. In addition, TUG1 inactivated MAPK1/ERK signaling by binding with LIN28B. And TUG1 overexpression's repression on HG-induced HK2 cell apoptosis and ERS was abrogated by MAPK1 signaling activation. Meanwhile, METTL14 knockdown or TUG1 overexpression protected against STZ-induced renal lesions and renal fibrosis in DKD mouse. CONCLUSION: METTL14 promoted renal tubular epithelial cell apoptosis and ERS by activating MAPK/ERK pathway through m6A modification of TUG1, thereby accelerating DKD progression.

Downregulation of m6A Methyltransferase in the Hippocampus of Tyrobp -/- Mice and Implications for Learning and Memory Deficits.

Loss-of-function mutations in the gene that encodes TYRO protein kinase-binding protein (TYROBP) cause Nasu-Hakola disease, a heritable disease resembling Alzheimer's disease (AD). Methylation of N6 methyl-adenosine (m6A) in mRNA plays essential roles in learning and memory. Aberrant m6A methylation has been detected in AD patients and animal models. In the present study, Tyrobp-/- mice showed learning and memory deficits in the Morris water maze, which worsened with age. Tyrobp-/- mice also showed elevated levels of total tau, Ser202/Thr205-phosphorylated tau and amyloid ß in the hippocampus and cerebrocortex, which worsened with aging. The m6A methyltransferase components METTL3, METTL14, and WTAP were downregulated in Tyrobp-/- mice, while expression of demethylases that remove the m6A modification (e.g., FTO and ALKBH5) were unaltered. Methylated RNA immunoprecipitation sequencing identified 498 m6A peaks that were upregulated in Tyrobp-/- mice, and 312 m6A peaks that were downregulated. Bioinformatic analysis suggested that most of these m6A peaks occur in sequences near stop codons and 3'-untranslated regions. These findings suggest an association between m6A RNA methylation and pathological TYROBP deficiency.

Circulating tumor cells predict prognosis following secondline AZD 9291 treatment in EGFR-T790M mutant non-small cell lung cancer patients.

PURPOSE: AZD9291 has been developed as third-generation epithermal growth factor receptor (EGFR)- tyrosine kinase inhibitor (TKI) with activities against T790M mutation. This study aimed to isolate and quantify the circulating tumor cells (CTCs) in non-small cell lung cancer (NSCLC) patients after first-line EGFR TKIs and investigate their role in providing prognostic information. METHODS: Enrolled patients confirmed with EGFR T790M mutation received AZD9291 80 mg orally once daily as second-line treatment. Serial blood samples were taken at baseline (CTC-d0) and on day 28 (CTC-d28) following the initiation of AZD9291 for detection of CTCs using the Cell-Search system. RESULTS: The CTC measurements were dichotomized as favorable (<5 CTCs) and unfavorable (≥5 CTCs) groups. Patients in the favorable group at baseline exhibited significantly longer median progression-free survival (PFS) compared with patients in the unfavorable group (9.3 vs. 6.5 months; p=0.0002). The PFS interval for patients in the favorable group on day 28 was 9.7 months, significantly longer than the median PFS time of 6.2 months achieved by patients in the unfavorable group (p=0.011). In univariate and multivariate analysis, CTC-d0 ≥5 vs CTC-d0=0-4 was significantly associated with poor PFS. CONCLUSIONS: This is the first report over the presence of CTCs and their prognostic role in patients with EGFR T790M-positive NSCLC following disease progression on an EGFR TKI. The use of serial CTC evaluation as a surrogate biomarker needs further validation in larger samples of patients.

The RNASEL -1385G/A polymorphism is associated with risk of prostate cancer in Africans.

The RNASEL -1385G/A (rs486907) variant has been reported to be associated with increased risk of prostate cancer. However, these associations are not consistent among studies. To address this issue, we performed a meta-analysis to evaluate the association between RNASEL -1385G/A polymorphism and prostate cancer risk. The PubMed, Embase, and Web of Science databases were searched for relevant papers published in the past 20 years from 1997 to 2017. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of associations. Based on our search for manuscripts reporting prostate cancer susceptibility related to the rs486907 polymorphism, 16 case-control studies from 13 different publications were retrieved. No significantly positive associations were found for the polymorphism and prostate cancer susceptibility in the total population. When stratified by ethnicity, the results demonstrated that the -1385G/A polymorphism was associated with a decreased cancer risk in Africans (GG vs AA: OR =0.371, 95% CI =0.176-0.783; GG/GA vs AA: OR =0.368, 95% CI =0.175-0.776). We also found that the rs486907 polymorphism was associated with a decreased cancer risk in hospital-based controls (GG vs AA: OR =0.697, 95% CI =0.488-0.996; GG + GA vs AA: OR =0.701, 95% CI =0.502-0.978). Our meta-analysis suggests that polymorphism in the RNASEL gene is a protective factor against prostate cancer in Africans. Further studies using larger sample sizes should be conducted to elucidate the role of gene polymorphism in prostate cancer risk.

Relationship between ADH2 Arg47His variation and hepatocellular carcinoma susceptibility: a meta analysis.

BACKGROUND: To further investigate the relationship between ADH2 Arg47His variation and hepatocellular carcinoma (HCC) susceptibility through a meta-analysis. METHODS: The related articles were searched in PubMed, Embase and CNKI databases. And finally 518 cases and 607 controls were included in our meta-analysis Odds ratios (ORs) with 95% confidence intervals (95% CIs) were used to assess the relationship between ADH2 Arg47His variation and HCC risk. A fixed-effect model or a random-effect model was applied according to the between-study heterogeneity. RESULTS: Quantitative synthesis demonstrated that no significant association was found between ADH2 Arg47His variation and HCC susceptibility (His/His vs. Arg/Arg: OR=0.99, 95% CI=0.79-1.25; His/His + Arg/His vs. Arg/Arg: OR=1.01, 95% CI=0.86-1.20; His/His vs. Arg/Arg + Arg/His: OR=0.90, 95% CI=0.74-1.11; His vs. Arg: OR=0.98, 95% CI=0.86-1.11; Arg/His vs. Arg/Arg: OR=1.05, 95% CI=0.82-1.34). CONCLUSION: Our analysis showed that ADH2 Arg47His vvariation may not be associated with HCC susceptibility.

HapMap-based study on the association between MPO and GSTP1 gene polymorphisms and lung cancer susceptibility in Chinese Han population.

AIM: Myeloperoxidase (MPO) and glutathione S-transferase pi 1 (GSTP1) are important carcinogen-metabolizing enzymes. The aim of this study was to investigate the association between the common polymorphisms of MPO and GSTP1 genes and lung cancer risk in Chinese Han population. METHODS: A total of 266 subjects with lung cancer and 307 controls without personal history of the disease were recruited in this case control study. The tagSNPs approach was used to assess the common polymorphisms of MOP and GSTP1 genes and lung cancer risk according to the disequilibrium information from the HapMap project. The tagSNP rs7208693 was selected as the polymorphism site for MPO, while the haplotype-tagging SNPs rs1695, rs4891, rs762803 and rs749174 were selected as the polymorphism sites for GSTP1. The gene polymorphisms were confirmed using real-time PCR, cloning and sequencing. RESULTS: The four GSTP1 haplotype-tagging SNPs rs1695, rs4891, rs762803 and rs749174, but not the MPO tagSNP rs7208693, exhibited an association with lung cancer susceptibility in smokers in the overall population and in the studied subgroups. When Phase 2 software was used to reconstruct the haplotype for GSTP1, the haplotype CACA (rs749174+rs1695 + rs762803+rs4891) exhibited an increased risk of lung cancer among smokers (adjust odds ratio 1.53; 95%CI 1.04-2.25, P=0.033). Furthermore, diplotype analyses demonstrated that the significant association between the risk haplotype and lung cancer. The risk haplotypes co-segregated with one or more biologically functional polymorphisms and corresponded to a recessive inheritance model. CONCLUSION: The common polymorphisms of the GSTP1 gene may be the candidates for SNP markers for lung cancer susceptibility in Chinese Han population.

Current evidence on the four polymorphisms of VDR and breast cancer risk in Caucasian women.

There have been a few epidemiological studies reporting VDR polymorphisms including Fok1, Bsm1, Apa1 and Taq1with breast cancer incidence and therefore risk. The results however are controversial, often due to smaller sample size. Concerning most of the studies were performed on Caucasian women, we conducted this comprehensive meta-analysis encompassing 38,151 cases and 47,546 controls (Fok1: 13,152 cases, 17,443 controls; Bsm1: 14,755 cases, 18,633 controls; Apa1: 3080 cases, 3412 controls; Taq1: 7164 cases, 8068 controls) to better understand roles of the polymorphisms in breast cancer development among Caucasian population. We did not find any association of the most controversial genotype Fok1 with breast cancer risk in Caucasian women (ff vs. FF: OR = 1.05, 95% CI = 0.95-1.22, P = 0.32 for heterogeneity; ff vs. Ff: OR = 1.05, 95% CI = 0.94-1.17, P = 0.40; ff vs. Ff + FF: OR = 1.07, 95% CI = 0.95-1.14, P = 0.37 and ff + Ff vs. FF: OR = 1.04, 95% CI = 0.99-1.09, P = 0.23). For Bsm1, Apa1 and Taq1, no significant association was also not found in the homozygote comparison, heterozygote comparison, recessive and dominant models respectively. In conclusion, the current analysis suggested that the four polymorphisms (Fok1, Bsm1, Apa1 and Taq1) of VDR may be not associated with breast cancer risk in Caucasian women.

Polymorphisms in DNA repair genes of XRCC1, XPA, XPC, XPD and associations with lung cancer risk in Chinese people.

BACKGROUND: The carcinogenic chemicals and reactive oxygen species in tobacco can result in DNA damage. DNA repair genes play an important role in maintaining genome integrity. Genetic polymorphisms of DNA repair genes and smoking may contribute to susceptibility of lung cancer. METHODS: In this hospital-based case-control study, we investigated the relationship between 13 tagging single nucleotide polymorphisms (SNPs) in base excision repair pathway and nucleotide excision repair pathway genes, smoking, and lung cancer susceptibility. Thirteen tag SNPs were genotyped in 265 lung cancer patients and 301 healthy controls. Logistic regression and multifactor dimensionality reduction method were applied to explore the association and high-order gene-gene and gene-smoking interaction. RESULTS: In single tag SNP analysis, XPA rs2808668, XPC rs2733533, and XPD rs1799787 were significantly associated with lung cancer susceptibility. Joint effects analysis of XPA rs2808668, XPC rs2733533 and XPD rs1799787 showed that there was an increased risk of lung cancer with increasing numbers of risk alleles. Haplotype analysis showed that XRCC1 (rs25487, rs1799782, rs3213334) GCC had a positive association with lung cancer. Analysis of gene-gene and gene-smoking interaction by multifactor dimensionality reduction showed that a positive interaction existed between the four genes and smoking. The two-factor model, including XPC rs2755333 and smoking, had the best prediction ability for lung cancer. Compared with the C/C genotype of XPC rs2733533 and no smoking, the combination of genotype A carriers with XPC rs2733533 and heavy smokers (≥30 pack-year) had a 13.32-fold risk of lung cancer. CONCLUSION: Our results suggest multiple genetic variants in multiple DNA repair genes may jointly contribute to lung cancer risk through gene-gene and gene-smoking interactions.

Concomitant EGFR inhibitors combined with radiation for treatment of non-small cell lung carcinoma.

Epidermal growth factor receptor (EGFR) is considered to be one of the key driver genes in non-small cell lung cancer (NSCLC). Several clinical trials have shown great promise of EGFR tyrosine kinase inhibitors (TKIs) in the first-line treatment of NSCLC. Many advances have been made in the understanding of EGFR signal transduction network and the interaction between EGFR and tumor microenvironment in mediating cancer survival and development. The concomitant targeted therapy and radiation is a new strategy in the treatment of NSCLC. A number of preclinical studies have demonstrated synergistic anti-tumor activity in the combination of EGFR inhibitors and radiotherapy in vitro and in vivo. In the present review, we discuss the rationale of the combination of EGFR inhibitors and radiotherapy in the treatment of NSCLC.

[Interference of homologous sequences on the SNP study of CYP2A13 gene].

BACKGROUND AND OBJECTIVE: It has been proven that cytochrome P450 enzyme 2A13 (CYP2A13) played an important role in the association between single nucleotide polymorphisms (SNP) and human diseases. Cytochrome P450 enzymes are a group of isoenzymes, whose sequence homology may interfere with the study for SNP. The aim of this study is to explore the interference on the SNP study of CYP2A13 caused by homologous sequences. METHODS: Taqman probe was applied to detect distribution of rs8192789 sites in 573 subjects, and BLAST method was used to analyze the amplified sequences. Partial sequences of CYP2A13 were emplified by PCR from 60 cases. The emplified sequences were TA cloned and sequenced. RESULTS: For rs8192789 loci in 573 cases, only 3 cases were TT, while the rest were CT heterozygotes, which was caused by homologous sequences. There are a large number of overlapping peaks in identical sequences of 60 cases, and the SNP of 101 amino acid site reported in the SNP database is not found. The cloned sequences are 247 bp, 235 bp fragments. CONCLUSION: The homologous sequences may interfere the study for SNP of CYP2A13, and some SNP may not exist.

[Association between GSTM1 genetic polymorphism and lung cancer risk by SYBR green I real-time PCR assay].

BACKGROUND AND OBJECTIVE: Glutathione S-transferase M1 (GSTM1) is an important phase II metabolic enzyme gene which involves metabolism of various carcinogens in human body. Many studies showed that GSTM1 genetic polymorphism was associated with lung cancer risk. The aim of this study is to investigate the relationship between GSTM1 genetic polymorphism and lung cancer risk among Han nationality population in Tianjin district. METHODS: GSTM1 genetic polymorphism was detected by melting curve analysis of SYBR green I real-time PCR assay. Two hundred and sixty-five histological confirmed lung cancer patients and 307 health controls were recruited in this case-control study and the relationship between GSTM1 genetic polymorphism and lung cancer riskwas investigated. RESULTS: (1) The frequency of the GSTMI(-) in lung cancer and control groups was 56.6% and 57.0% respectively, and no significant difference was found between the distribution of the GSTM1 (-) genotype in the two groups (chi2 = 0.831, P = 0.362). (2) When considered the GSTM1(+) genotype as reference, there was no overall statistically increased lung cancer risk for carriers with the GSTM1(-) genotype adjusted by age, gender and smoking status (OR = 0.840, 95% CI: 0.578-1.221, P = 0.362). (3) The frequency of the GSTM1(-) genotype for squamous cell carcinoma, adenocarcinoma, SCLC and other histological types was 65.8%, 48.5%, 47.8% and 52.2% respectively, compared with the control group, no statistically increased lung cancer risk was observed (P > 0.05). CONCLUSION: No evidence is found between GSTMI genetic polymorphism and lung cancer risk among Han nationality population in Tianjin district.