Cuiju Wang

A polymorphism at the miR‐502 binding site in the 3′‐untranslated region of the histone methyltransferase SET8 is associated with hepatocellular carcinoma outcome

MicroRNAs (miRNAs) can bind to the 3′‐untranslated regions (UTRs) of messenger RNAs, where they interfere with translation and thereby regulate cell differentiation, apoptosis and tumorigenesis. Genetic polymorphisms in the 3′‐UTRs targeted by miRNAs alter the strength of miRNA binding in a manner that affects the behavior of individual miRNAs. The histone methyltransferase SET8 has been reported to methylate TP53 and regulate genomic stability. We analyzed a single‐nucleotide polymorphism (rs16917496) within the miR‐502 miRNA seed region for the 3′‐UTR of SET8 in Chinese patients with hepatocellular carcinoma (HCC). The SET8 CC genotype was independently associated with longer postoperative survival in patients with HCC by multivariate analysis (relative risk, 0.175; 95% CI = 0.053–0.577; p = 0.004). The SET8 CC genotype was associated with reduced SET8 protein levels based on the immunostaining of 51 HCC tissue samples. We also found that the low SET8 levels were associated with longer HCC survival. Our data suggest that SET8 modifies HCC outcome by altering its expression, which depends, at least in part, on its binding affinity with miR‐502. The analysis of genetic polymorphisms in miRNA binding sites can help to identify patient subgroups that are at high risk for poor disease outcomes.

Identification of sequence polymorphism in the D-Loop region of mitochondrial DNA as a risk factor for hepatocellular carcinoma with distinct etiology

BackgroundHepatocellular carcinoma (HCC) is frequently preceded by hepatitis virus infection or alcohol abuse. Genetic backgrounds may increase susceptibility to HCC from these exposures.MethodsMitochondrial DNA (mtDNA) of peripheral blood, tumor, and/or adjacent non-tumor tissue from 49 hepatitis B virus-related and 11 alcohol-related HCC patients, and from 38 controls without HCC were examined for single nucleotide polymorphisms (SNPs) and mutations in the D-Loop region.ResultsSingle nucleotide polymorphisms (SNPs) in the D-loop region of mt DNA were examined in HCC patients. Individual SNPs, namely the 16266C/T, 16293A/G, 16299A/G, 16303G/A, 242C/T, 368A/G, and 462C/T minor alleles, were associated with increased risk for alcohol- HCC, and the 523A/del was associated with increased risks of both HCC types. The mitochondrial haplotypes under the M haplogroup with a defining 489C polymorphism were detected in 27 (55.1%) of HBV-HCCand 8 (72.7%) of alcohol- HCC patients, and in 15 (39.5%) of controls. Frequencies of the 489T/152T, 489T/523A, and 489T/525C haplotypes were significantly reduced in HBV-HCC patients compared with controls. In contrast, the haplotypes of 489C with 152T, 249A, 309C, 523Del, or 525Del associated significantly with increase of alcohol-HCC risk. Mutations in the D-Loop region were detected in 5 adjacent non-tumor tissues and increased in cancer stage (21 of 49 HBV-HCC and 4 of 11 alcohol- HCC, p < 0.002).ConclusionsIn sum, mitochondrial haplotypes may differentially predispose patients to HBV-HCC and alcohol-HCC. Mutations of the mitochondrial D-Loop sequence may relate to HCC development.

Single nucleotide polymorphisms in the mitochondrial displacement loop and outcome of esophageal squamous cell carcinoma

BackgroudAccumulation of single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) has been described for different types of cancers and might be associated with cancer risk and disease outcome. We used a population-based series of esophageal squamous cell carcinoma (ESCC) patients for investigating the prediction power of SNPs in mitochondrial D-loop.MethodsThe D-loop region of mtDNA was sequenced for 60 ESCC patients recorded in the Fourth Hospital of Hebei Medical University between 2003 and 2004. The 5 year survival curve were calculated with the Kaplan-Meier method and compared by the log-rank test at each SNP site, a multivariate survival analysis was also performed with the Cox proportional hazards method.ResultsThe SNP sites of nucleotides 16274G/A, 16278C/T and 16399A/G were identified for prediction of post-operational survival by the log-rank test. In an overall multivariate analysis, the 16278 and 16399 alleles were identified as independent predictors of ESCC outcome. The length of survival of patients with the minor allele 16278T genotype was significantly shorter than that of patients with 16278C at the 16278 site (relative risk, 3.001; 95% CI, 1.029 - 8.756; p = 0.044). The length of survival of patients with the minor allele 16399G genotype was significantly shorter than that of patients with the more frequent allele 16399A at the 16399 site in ESCC patients (relative risk, 3.483; 95% CI, 1.068 - 11.359; p = 0.039).ConclusionGenetic polymorphisms in the D-loop are independent prognostic markers for patients with ESCC. Accordingly, the analysis of genetic polymorphisms in the mitochondrial D-loop can help identify patient subgroups at high risk of a poor disease outcome.

Sequence polymorphisms of mitochondrial D-loop and hepatocellular carcinoma outcome.

Accumulation of mutations and single nucleotide polymorphisms (SNPs) in the displacement loop (D-loop) of mitochondrial DNA (mtDNA) might be associated with cancer risk and disease outcome. We investigated the prediction power of D-loop SNPs in hepatocellular carcinoma (HCC) patients. No mutation in these HCC patients has prediction power for post-operational survival, whereas two SNP sites (nucleotides 146 T/C and 150 C/T) were identified by the log-rank test for statistically significant prediction of HCC survival. In an overall multivariate analysis, allele 146 was identified as an independent predictor of HCC outcome. The length of survival of patients with allele 146C was significantly shorter than that of patients with allele 146T (relative risk, 2.781; 95% CI, 1.127-6.859; p=0.026). The analysis of genetic polymorphisms in the mitochondrial D-loop can help identify patient subgroups at high risk of a poor disease outcome.

Sirtuin-3 (SIRT3) expression is associated with overall survival in esophageal cancer☆

Sirtuin-3 (SIRT3) was immunostained in 94 samples of esophageal cancer tissues and semiquantified using the HSCORE method to evaluate the predictive value of SIRT3 expression levels on esophageal cancer outcome. The relationship between SIRT3 expression and the 5-year survival rate of postoperational esophageal cancer patients was assessed with the Kaplan-Meier method. High expression of SIRT3 is associated with a shorter survival time in esophageal cancer patients, as shown by the log-rank test (P = .007), and the level of SIRT3 expression was identified as an independent predictor for esophageal cancer outcome using Cox proportional hazards model analysis (relative risk, 2.061; 95% confidence interval, 1.050-4.046; P = .036). SIRT3 expression was associated with esophageal cancer outcome. The analysis of SIRT3 levels can help in the identification of patient subgroups that are at high risk for poor disease outcomes.

Ontogeny-Driven rDNA Rearrangement, Methylation, and Transcription, and Paternal Influence

Gene rearrangement occurs during development in some cell types and this genome dynamics is modulated by intrinsic and extrinsic factors, including growth stimulants and nutrients. This raises a possibility that such structural change in the genome and its subsequent epigenetic modifications may also take place during mammalian ontogeny, a process undergoing finely orchestrated cell division and differentiation. We tested this hypothesis by comparing single nucleotide polymorphism-defined haplotype frequencies and DNA methylation of the rDNA multicopy gene between two mouse ontogenic stages and among three adult tissues of individual mice. Possible influences to the genetic and epigenetic dynamics by paternal exposures were also examined for Cr(III) and acid saline extrinsic factors. Variables derived from litters, individuals, and duplicate assays in large mouse populations were examined using linear mixed-effects model. We report here that active rDNA rearrangement, represented by changes of haplotype frequencies, arises during ontogenic progression from day 8 embryos to 6-week adult mice as well as in different tissue lineages and is modifiable by paternal exposures. The rDNA methylation levels were also altered in concordance with this ontogenic progression and were associated with rDNA haplotypes. Sperm showed highest level of methylation, followed by lungs and livers, and preferentially selected haplotypes that are positively associated with methylation. Livers, maintaining lower levels of rDNA methylation compared with lungs, expressed more rRNA transcript. In vitro transcription demonstrated haplotype-dependent rRNA expression. Thus, the genome is also dynamic during mammalian ontogeny and its rearrangement may trigger epigenetic changes and subsequent transcriptional controls, that are further influenced by paternal exposures.

miR-502 medaited histone methyltransferase SET8 expression is associated with outcome of esophageal squamous cell carcinoma

The histone methyltransferase SET8, whose expression is regulated by miR-502 though the binding site in the 3′ UTR of SET8, implicated in cancer development. Single nucleotide polymorphism (SNP) of rs16917496 located in the miR-502 and SET8 binding site was analyzed in esophageal squamous cell carcinoma (ESCC) patients, the SET8 C/C genotype was independently associated with longer post-operative survival by multivariate analysis (relative risk, 2.250; 95% CI, 1.041–4.857; p = 0.039). Moreover, the reduced SET8 expression mediated by SET8 C/C genotype was associated with longer ESCC survival. Functional assay indicated that the SET8 knock down could inhibit proliferation and promote apoptosis of ESCC cells. The subsequent assay also showed the markedly inhibition of ESCC cell migration and invasion by SET8 knock down. Our data suggested that the altering SET8 expression, which is mediated at least partly by miR-502 through changing the binding affinity between miR-502 and SET8 3′ UTR, could modify the ESCC outcome by inhibiting the proliferation and invasion as well as promoting the apoptosis of ECSS cell. Our data indicated that SET8 was a new target for ESCC therapy.

Single nucleotide polymorphisms in the D-loop region of mitochondrial DNA is associated with colorectal cancer outcome

Abstract Single nucleotide polymorphisms (SNPs) in the displacement loop (D-Loop) of mitochondrial DNA (mtDNA) has been identified for their association with the risk and outcome in many cancers. We have identified risk associated D-loop SNPs for colorectal cancer previously, in the present study, we evaluate their prognostic value for postoperative survival of colorectal cancer (CRC). The minor haplotype of nucleotides 16290T and frequent haplotype of nucleotide 16298T in the hypervariable segment 1 (HV1) region of the D-loop were identified for their association with high survival rate of CRC. After adjusted with COX proportional hazard model, the nucleotide site of 16290 was identified as independent predictor for CRC (RR, 0.379; 95% CI, 0.171–0.839; p = 0.017). In conclusion, SNPs in the mtDNA D-Loop were found to be valuable markers for colorectal cancer outcome evaluation.

Single nucleotide polymorphisms in the mitochondrial displacement loop and age at onset of non-Hodgkin lymphoma.

Objective Single nucleotide polymorphisms (SNPs) accumulated frequently in the mitochondrial displacement loop (D-loop) in many cancers. We had identified cancer risk-associated SNPs in the D-loop of non-Hodgkin lymphoma (NHL) patients previously, in this study, we investigated the association of age at onset and D-loop SNPs in NHL patients. Materials and methods The D-loop region of mtDNA was sequenced for 133 NHL patients recorded at the Fourth Hospital of Hebei Medical University. The Kaplan–Meier method was used to identify age at onset-associated SNPs in the D-loop of NHL patients. The Cox proportional hazards model was used to identify independent risk factors for age at onset. Results The SNP sites of nucleotides 146C/T, 151T/C, 194T/C, 315C/C insert, 523Del/A, and 525Del/C were identified for their association with age at onset, by the logrank test. In an overall multivariate analysis, allele 146 (relative risk, 0.403; 95% confidence interval [CI]: 0.182–0.895) (P = 0.026), allele 151 (relative risk, 0.378; 95% CI: 0.165–0.868) (P = 0.022), and allele 315 (relative risk, 3.554; 95% CI: 1.344–9.400) (P = 0.011) were identified as independent predictors for age at onset in NHL patients. Conclusion SNPs in the D-loop can predict age at onset in NHL patients. Analysis of the D-loop SNPs can help identify NHL patient subgroups at high risk of early onset.

Molecular and organismal changes in offspring of male mice treated with chemical stressors

Both gene methylation changes and genetic instability have been noted in offspring of male rodents exposed to radiation or chemicals, but few specific gene targets have been established. Previously, we identified the gene for ribosomal RNA, rDNA, as showing methylation change in sperm of mice treated with the preconceptional carcinogen, chromium(III) chloride. rDNA is a critical cell growth regulator. Here, we investigated the effects of paternal treatments on rDNA in offspring tissue. A total of 93 litters and 758 offspring were obtained, permitting rigorous mixed‐effects models statistical analysis of the results. We show that the offspring of male mice treated with Cr(III) presented increased methylation in a promoter sequence of the rDNA gene, specifically in lung. Furthermore polymorphic variants of the multi‐copy rDNA genes displayed altered frequencies indicative of structural changes, as a function of both tissue type and paternal treatments. Organismal effects also occurred: some groups of offspring of male mice treated with either Cr(III) or its vehicle, acidic saline, compared with those of untreated mice, had altered average body and liver weights and levels of serum glucose and leptin. Males treated directly with Cr(III) or acidic saline presented serum hormone changes consistent with a stress response. These results establish for the first time epigenetic and genetic instability effects in a gene of central physiological importance, in offspring of male mice exposed preconceptionally to chemicals, possibly related to a stress response in these males.