Clinical significance of aberrant cyclin-dependent kinase-like 2 methylation in hepatocellular carcinoma.

BACKGROUND AND AIMS: Aberrant DNA methylation of cyclin-dependent kinase-like 2 (CDKL2) had been observed in several types of tumors. Herein, the present study was aimed to explore the epigenetic and expression status of CDKL2 and evaluate the diagnostic potential of CDKL2 methylation in hepatocellular carcinoma (HCC). METHODS: The methylation status of CDKL2 was detected by methylation-sensitive restriction enzyme based quantitative PCR (MSRE-qPCR) and bisulfite genomic sequencing (BGS). The mRNA expression of CDKL2 was measured using real-time quantitative PCR (qPCR). The correlations between the methylation of CDKL2 and mRNA expression, clinicopathological features were evaluated. RESULTS: Compared with normal liver tissues, the methylation levels of CDKL2 were significantly increased in the HCC tissues and cell lines (All p < 0.05). And the receiver operating characteristic (ROC) analysis showed that the hypermethylation of CDKL2 had a high specificity and sensitivity to distinguish adjacent non-tumor tissues from HCC tissues. Additionally, the mRNA expression levels of CDKL2 were decreased both in HCC tissues and cell lines than those in normal liver tissues (All p < 0.05), and the expression could be upregulated by 5-aza-2'-deoxycytidine treatment in HCC cell lines. Furthermore, the methylation of CDKL2 was negatively correlated with its mRNA expression (p < 0.001, rs = -0.513), and was associated with gender (p = 0.023), age (p = 0.001) and tumor size (p = 0.016). CONCLUSIONS: Our results showed that CDKL2 promoter hypermethylation played an important role in hepatocarcinogenesis and might be a valuable biomarker for HCC diagnosis.

A novel mutation in nuclear prelamin a recognition factor-like causes diffuse pulmonary arteriovenous malformations.

Two daughters in a Chinese consanguineous family were diagnosed as diffuse pulmonary arteriovenous malformations (PAVMs) and screened using whole exome sequencing (WES) and copy number variations (CNVs) chips. Though no mutation was found in the established causative genes of capillary malformation-AVMs (CM-AVMs) or PAVMs, Ser161Ile (hg19 NM_022493 c.482G>T) mutation in nuclear prelamin A recognition factor-like (NARFL) was identified. Ser161Ile mutation in NARFL conservation region was predicted to be deleterious and absent in 500 population controls and Exome Aggregation Consortium (ExAC) Database. And there was a dosage effect of the mutation on mRNA levels among family members and population controls, consistent with the instability of mutant mRNA in vitro. Accordingly, in lung tissue of the proband, NARFL protein expression was reduced but Fe3+ was overloaded with vascular endothelial growth factor (VEGF) overexpression. Furthermore, NARFL-knockdown cell lines demonstrated decreased activity of cytosolic aconitase, while NARFL-knockout zebrafish presented ectopic subintestinal vessels sprouts and upregulated VEGF. So we concluded that the Ser161Ile mutant induced NARFL deficiency and eventually diffuse PAVMs probably through VEGF pathway. In a word, we detected a functional mutation in NARFL, which might be the pathogenic gene in this pedigree.

Associations of Polymorphisms in MTHFR Gene with the Risk of Age-Related Cataract in Chinese Han Population: A Genotype-Phenotype Analysis.

Homocysteine (Hcy) is a potential risk factor for age-related cataract (ARC). Methylenetetrahydrofolate reductase (MTHFR) is the key enzyme for Hcy metabolism, and variants of MTHFR may affect MTHFR enzyme activity. This study mainly evaluated the associations between variants in MTHFR gene, plasma MTHFR enzyme activity, total Hcy (tHcy) levels and ARC risk in Chinese population. Four single nucleotide polymorphisms (SNPs) in MTHFR gene were genotyped using the high-resolution melting (HRM) method in 502 ARC patients (mean age, 70.2 [SD, 9.0], 46.0% male) and 890 healthy controls (mean age, 67.1 [SD, 11.1], 47.6% male). The plasma MTHFR activity, folic acid (FA), vitamins B12 and B6 levels were detected by enzyme-linked immunosorbent assays (ELISA). The plasma tHcy levels were measured by an automated enzymatic assay. After the Bonferroni correction, the minor allele T of SNP rs1801133 showed a significant association with an increased risk of overall ARC (OR = 1.26, P = 0.003). Consistent association was also found between SNP rs1801133 and cortical ARC risk (OR = 1.44, P = 0.003). Haplotype analyses revealed an adverse effect of the haplotype "C-A-T-C" (alleles in order of SNPs rs3737967, rs1801131, rs1801133 and rs9651118) on ARC risk (OR = 1.55, P = 0.003). Moreover, in a joint analysis of SNPs rs9651118 and rs1801133, subjects with two unfavorable genotypes had a 1.76-fold increased risk of ARC compared with the reference group, and a statistically significant dose-response trend (Ptrend = 0.001) was also observed. Further, in healthy controls and patients with cortical ARC, the allele T of SNP rs1801133 and the increasing number of unfavorable genotypes were significantly correlated with decreased MTHFR activity as well as increased tHcy levels. However, there was no significant association between FA, vitamins B12, B6 levels and MTHFR variants. Our data indicated that variants in MTHFR gene might individually and jointly influence susceptibility to ARC by affecting MTHFR enzyme activity and tHcy levels.