Effects of metallothionein-1 genetic polymorphism and cigarette smoking on the development of hepatocellular carcinoma

Genetic Variations in Metallothionein Genes and Susceptibility to Hypertensive Disorders of Pregnancy: A Case-Control Study

Background: The involvement of oxidative stress in the pathological process of hypertensive disorders of pregnancy (HDP) gives rise to the interest in exploring the association of genetic variations in antioxidant metallothionein (MT) genes with HDP susceptibility.

Methods: Seventeen single-nucleotide polymorphisms(SNPs) in MT genes were selected to conduct genotyping based on a case-control study consisting of 371 HDP cases (pregnancy with chronic hypertension (66), gestational hypertension (172), and preeclampsia or preeclampsia superimposed on chronic hypertension (133)) and 479 controls. The association between SNPs in MTs and the risk of HDP was estimated with unconditional logistic regression analysis and further tested with the false-positive report probability (FPRP) procedure. The joint effects of SNPs on the HDP risk were assessed by haplotype analysis.

Results: After the adjustment for age and pre-pregnancy body mass index (pre-BMI) in the logistic regress analysis and followed by the FPRP test, the genetic variation rs10636 (OR = 0.46, 95% CI: 0.30–0.71 for GG vs. CC, p = 0.000 and OR = 0.48, 95% CI: 0.32–0.73 for GG vs. CG/CC, p = 0.001) in MT2A was associated with gestational hypertension. Other four SNPs, that is, rs11076161 (OR = 1.89, 95% CI: 1.35–2.63 for GG vs. GA/AA, p = 0.000) in MT1A; rs7191779 (OR = 1.54, 95% CI: 1.11–2.13 for CC vs. CG/GG, p = 0.010) in MT1B; rs8044719 (OR = 0.57, 95% CI: 0.40–0.80 for GT vs. GG, p = 0.001) in MT1DP; and rs8052334 (OR = 1.52, 95% CI: 1.10–2.11 for TT vs. TC/CC, p = 0.012) in MT1B were significantly associated with the susceptibility of HDP. The haplotype analysis among 11, 10, 10, and seven SNPs in MT (MT1A, MT2A, MT1M, MT1B, and MT1DP) genes showed that eight (A-C-G-T-C-G-A-G-C-G-C, OR = 4.559; A-C-T-C-C-C-A-G-C-G-C, OR = 5.777; A-C-T-T-C-G-A-G-C-G-C, OR = 4.590; G-A-T-C-C-G-C-G-G-C-C, OR = 4.065; G-A-T-C-G-C-C-G-G-C-C, OR = 4.652; G-A-T-T-C-C-C-G-G-C-C, OR = 0.404; G-C-T-C-C-C-A-G-G-C-C, OR = 1.901; G-C-T-T-C-C-A-G-G-C-C, and OR = 3.810), five (C-G-A-T-C-A-C-C-G-G, OR = 2.032; C-G-A-T-C-G-C-C-G-G, OR = 2.077; G-A-C-T-C-A-C-C-T-G, OR = 0.564; G-G-A-G-C-A-C-C-G-G, OR = 5.466; G-G-A-T-T-A-G-C-G-G, and OR = 0.284), five (A-C-G-T-C-G-A-G-C-C, OR = 2.399; A-C-T-C-C-C-C-T-G-G, OR = 0.259; G-A-T-C-C-C-C-G-G-C, OR = 1.572; G-A-T-C-G-C-C-G-G-C, OR = 0.001; G-C-T-C-G-C-A-G-G-C, and OR = 2.512), and five (A-C-T-C-C-C-G, OR = 0.634; G-A-G-C-C-C-G, OR = 4.047; G-A-T-T-G-C-G, OR = 0.499; G-C-G-T-C-A-G, and OR = 7.299; G-C-T-C-C-A-G, OR = 1.434) haplotypes were significantly associated with pregnancy with chronic hypertension, gestational hypertension, preeclampsia, or preeclampsia superimposed on chronic hypertension and HDP.

Conclusion: These variant MT alleles and their combination patterns may be used as genetic markers for predicting HDP susceptibility.

Revisiting the metallothionein genes polymorphisms and the risk of oral squamous cell carcinoma in a Brazilian population

Background

Metallothioneins (MTs) gene polymorphisms have been associated with the ability of free radical scavenging and detoxification of heavy metals leading to cancer development. Our aim was to revisit, in a Brazilian population, single-nucleotide polymorphisms (SNPs) of the MT gene family previously associated with oral squamous cell carcinoma (OSCC).

Material and Methods

A case-control investigation with 28 OSCC patients and 45 controls was conducted, using conventional risk factors (tobacco use and alcohol consumption) as covariates. SNPs genotyping for rs8052334 (MT1B), rs964372 (MT1B), and rs1610216 (MT2A) was performed by PCR-RFLP, and SNPs for rs11076161 (MT1A) were analyzed by TaqMan assay.

Results

The only SNP associated with increased risk for OSCC was the MT-1A AA genotype (OR = 4.7; p = 0.01). We have also evidenced for the first time a significant linkage disequilibrium between the SNPs of MT-2A and MT-1A in this population with the highest frequency (30%) of the unfavorable haplotype G/A/C/T (rs1610216 / rs11076161 / rs964372 / rs8052334) of MT gene polymorphisms (OR = 6.2; p = 0.04). Interestingly, after removing the effects of conventional risk factors, we have uncovered the significance of the AA genotype of the rs11076161 with increased odds of 19-fold higher towards OSCC development.

Conclusions

This is the first demonstration that a significant linkage disequilibrium among gene polymorphisms of the MT family may affect susceptibility to oral cancer, which is conditioned by the G/A/C/T haplotype (rs1610216/rs11076161/rs964372/ rs8052334) and the MT-1A gene polymorphism has a potential clinical utility for the OSCC risk assessment.

Key words:Oral squamous cell carcinoma, polymorphism, metallothionein, oral cancer.

METALLOTHIONEIN-2A (RS1610216&RS28366003) GENE POLYMORPHISMS AND THE RISK OF STOMACH ADENOCARCINOMA

ABSTRACT BACKGROUND: Gastric cancer is the fourth most common cause of worldwide cancer. Also in contrast to the huge advances in curing, the chance of living is very low even in surgery cases. Having a genetic predisposition plays an important role in cancer development. The association between Metallothionein-2A gene polymorphisms and the risk of adenocarcinoma has been widely studied, yet there is only one study on stomach diseases. OBJECTIVE: In this study, we aimed to investigate the association between 2 (MT-2A) polymorphisms and adenocarcinoma. METHODS: This cross-sectional case control study was performed between Mach 2014 and January 2015 at the Tuba Hospital of Sari, Iran. Peripheral blood samples were collected in EDTA tube. DNA extraction was performed using the spin column procedure. The MT-2A polymorphisms MT-2A (rs1610216), (rs28366003) were determined by polymerase chain reaction-restriction fragment length polymorphism analysis in 95 a topic adenocarcinoma patients and 90 healthy individuals from Iranian population. RESULTS: The MT-2A rs1610216 polymorphism increased the risk of adeno carcinoma in our Iranian population [OR: 3.8533; 95%CI, 1.3155-11.2869; P=0.0139] and rs28366003 [OR: 4.0978; 95%CI, 1.2521-13.4108; P=0.0197]. CONCLUSION: The MT-2A gene polymorphism was associated with the risk of adenocarcinoma in the Iranian population.

Using Phytochemicals to Investigate the Activation of Nicotine Detoxification via Upregulation of CYP2A6 in Animal Models Exposed Tobacco Smoke Condensate by Intratracheal Instillation

This study examined the efficacy of standardized Smilax china L. root extract (SSCR) containing chlorogenic acid on detoxifying nicotine from tobacco smoke condensate (TSC) in vitro and in vivo. Chlorogenic acid is an identified bioactive component in SSCR by ultraperformance liquid chromatography/photodiode array/electrospray ionization/mass spectroscopy (UPLC/PDA/ESI/MS). HepG2 liver cells and A549 lung cells were carried for measuring ROS and antioxidant enzymes. Sprague-Dawley rats were treated with nicotine by intratracheal instillation (ITI). Cell viabilities by pretreatments of 5, 12.5, and 25, 50 μg SSCR/mL ranged from 41 to 76% in HepG2 and 65 to 95% in A549. Pretreatments of SSCR inhibited TSC-mediated production of reactive oxygen species (ROS) by 8 and 10% in HepG2 and A549 cells, respectively. However, the expression of CAT, SOD1, and AOX1 was downregulated by SSCR in the both cells. The highest conversion of cotinine was observed at 50 μg/mL of SSCR after 120 min of incubation. SSCR upregulated CYP2A6 3-fold in A549 cells regardless of TSC cotreatment. When Sprague-Dawley rats were treated with nicotine by ITI or subjected to SSCR administration for 14 days, the levels of cotinine in urine increased in SSCR treatment only. The cellular level of antioxidant capacity at 10 or 100 mg/kg body weight/day of SSCR treatment was 1.89 and 1.86 times higher than those of nicotine-control. Results suggest that the intake of SSCR can detoxify nicotine by elevating nicotine conversion to cotinine and antioxidant capacity.

A new prognostic score can predict survival after hepatocellular carcinoma treatment in a cohort of 1302 Egyptian hepatocellular carcinoma patients

INTRODUCTION

Survival of hepatocellular carcinoma (HCC) differs between regions and countries according to the different underlying factors and the degree of standard of care that enables early diagnosis and management. Our aim was to identify the most potent predictive factors of survival in Egyptian HCC patients receiving curative or palliative treatments.

PATIENTS AND METHODS

This retrospective study included 1302 HCC patients attending the HCC multidisciplinary clinic, Cairo University, between February 2009 and December 2016. Clinical, laboratory, tumor characteristics, and treatment data were collected. Prognostic scores for each of the treatment categories, curative or palliative, were developed using routine laboratory tests.

RESULTS

Patients were predominantly men, mean age 57.79±7.56 years. All cases developed HCC in addition to cirrhosis, mainly hepatitis C virus-related (88.2%). Most of the patients were Child-Pugh A (56.8%) or B (34.4%) and had single lesions. Transarterial chemoembolization was the most common line of treatment (42.08%). The overall median survival was 18.3 months from the date of diagnosis. Cigarette smoking, Child-Pugh score, performance status, number and size of the focal lesion, α-fetoprotein, and application of a specific treatment, particularly curative treatment, were the significant independent prognostic factors for survival. We found no impact of diabetes mellitus or hypertension on survival. Multidisciplinary HCC clinic predictive scores of survival after palliative and curative treatments were developed including independent prognostic factors, age, and portal vein status.

CONCLUSION

A new Egyptian prognostic score of tumor and patients factors can predict the survival of patients with HCC after palliative and curative treatments.

An insight into the complex roles of metallothioneins in malignant diseases with emphasis on (sub)isoforms/isoforms and epigenetics phenomena

Metallothioneins (MTs) belong to a group of small cysteine-rich proteins that are ubiquitous throughout all kingdoms. The main function of MTs is scavenging of free radicals and detoxification and homeostating of heavy metals. In humans, 16 genes localized on chromosome 16 have been identified to encode four MT isoforms labelled by numbers (MT-1-MT-4). MT-2, MT-3 and MT-4 proteins are encoded by a single gene. MT-1 comprises many (sub)isoforms. The known active MT-1 genes are MT-1A, -1B, -1E, -1F, -1G, -1H, -1M and -1X. The rest of the MT-1 genes (MT-1C, -1D, -1I, -1J and -1L) are pseudogenes. The expression and localization of individual MT (sub)isoforms and pseudogenes vary at intra-cellular level and in individual tissues. Changes in MT expression are associated with the process of carcinogenesis of various types of human malignancies, or with a more aggressive phenotype and therapeutic resistance. Hence, MT (sub)isoform profiling status could be utilized for diagnostics and therapy of tumour diseases. This review aims on a comprehensive summary of methods for analysis of MTs at (sub)isoforms levels, their expression in single tumour diseases and strategies how this knowledge can be utilized in anticancer therapy.

Effects of Curcumin on Tobacco Smoke-induced Hepatic MAPK Pathway Activation and Epithelial-Mesenchymal Transition In Vivo

Tobacco smoke is a major risk factor for hepatic cancer. Epithelial-mesenchymal transition (EMT) induced by tobacco smoke is crucially involved in the initiation and development of cancer. Mitogen-activated protein kinase (MAPK) pathways play important roles in tobacco smoke-associated carcinogenesis including EMT process. The chemopreventive effect of curcumin supplementation against cancers has been reported. In this study, we investigated the effects of tobacco smoke on MAPK pathway activation and EMT alterations, and then the preventive effect of curcumin was examined in the liver of BALB/c mice. Our results indicated that exposure of mice to tobacco smoke for 12 weeks led to activation of ERK1/2, JNK, p38 and ERK5 pathways as well as activator protein-1 (AP-1) proteins in liver tissue. Exposure of mice to tobacco smoke reduced the hepatic mRNA and protein expression of the epithelial markers, while the hepatic mRNA and protein levels of the mesenchymal markers were increased. Treatment of curcumin effectively attenuated tobacco smoke-induced activation of ERK1/2 and JNK MAPK pathways, AP-1 proteins and EMT alterations in the mice liver. Our data suggested the protective effect of curcumin in tobacco smoke-triggered MAPK pathway activation and EMT in the liver of BALB/c mice, thus providing new insights into the chemoprevention of tobacco smoke-associated hepatic cancer. Copyright © 2017 John Wiley & Sons, Ltd.

No contribution of lifestyle and environmental exposures to gender discrepancy of liver disease severity in chronic hepatitis b infection: Observations from the Haimen City cohort

BACKGROUND

Previous studies have noted significant gender difference in the risk of liver cancer among hepatitis B chronic infection patients. Some indicated that it might be due to lifestyle-related differences. This paper tests whether or not such a gender discrepancy among the chronic hepatitis B population is confounded by lifestyle and environment related exposures.

METHODS

We retrieved a sample of 1863 participants from a prospective cohort in Haimen City, China in 2003. Liver disease severity was categorized as "normal", "mild", "moderate", and "severe" based on a clinical diagnosis. Lifestyle and environmental exposures were measured by questionnaires. We used factor analysis and individual variables to represent lifestyle and environmental exposures. We applied the cumulative logit models to estimate the effect of gender on liver disease severity and how it was impacted by lifestyle and environmental exposures.

RESULTS

Gender and HBeAg positivity were independent risk factors for more severe liver disease. Compared to females, males were 2.08 times as likely to develop more severe liver disease (95% CI: 1.66-2.61). Participants who were HBeAg positivite were 2.19 times (95% CI: 1.61-2.96) as likely to develop more severe liver disease compared to those who were negative. Controlling for lifestyle and environmental exposures did not change these estimations.

CONCLUSIONS

Males in the HBV infected population have an increased risk of severe liver disease. This gender effect is independent of the lifestyle and environmental exposures addressed in this study. Our findings support the hypothesis that gender discrepancies in HCC risk are attributable to intrinsic differences between males and females.

Metallothionein polymorphisms in a Northern Spanish population with neovascular and dry forms of age-related macular degeneration

BACKGROUND

To elucidate the potential role of single nucleotide polymorphisms (SNPs) in the metallothionein (MT) genes in Northern Spanish patients with age-related macular degeneration (AMD).

METHODS

A total of 130 unrelated Northern Spanish natives diagnosed with AMD (46 dry, 35 neovascular, and 49 mixed) and 96 healthy controls, matched by age and ethnicity, were enrolled in a case-control study. DNA was isolated from peripheral blood and genotyped for 14 SNPs located at 5 MT genes (MT1A: rs11076161, rs 11640851, rs8052394, and rs7196890; MT1B: rs8052334, rs964372, and rs7191779; MT1M: rs2270836 and rs9936741; MT2A: rs28366003, rs1610216, rs10636, and rs1580833; MT3: rs45570941) using TaqMan probes. The association study was performed using the HaploView 4.0 software.

RESULTS

The allelic and genotypic frequencies analysis revealed that rs28366003 at MT2A gene is significantly associated with dry AMD. The frequency of genotype AG was significantly higher in dry AMD than in control cases (p = 2.65 × 10^-4; AG vs. AA) conferring more than ninefold increased risk to dry AMD (OR = 9.39, 95% CI: 2.11-41.72), whereas the genotype AA confers disease protection (OR = 0.82, 95% CI: 0.71-0.95). No statistically significant differences were observed between AMD subjects and controls in the rest of the 14 SNPs analyzed.

CONCLUSIONS

The present study is the first to investigate the potential association of SNPs at MT genes with susceptibility to AMD. We found a significant association of SNP rs28366003 at MT2A gene with susceptibility to the dry form of AMD in a Northern Spanish population.

Dysregulation of metallothionein and circadian genes in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the major threat to human health, and disruption of circadian clock genes is implicated in hepatocarcinogenesis. This study examined the dysregulation of metallothioneins and circadian genes in achieved human HCC (n = 24), peri-HCC tissues (n = 24) as compared with normal human livers (n = 36). Total RNA was extracted and reverse transcribed. Real-time RT-qPCR was performed to determine the expression of genes of interest. The results demonstrated the downregulation of metallothionein-1 (MT-1), MT-2, and metal transcription factor-1 (MFT-1) in human HCC as compared with Peri-HCC and normal tissues. MTs are a biomarker for HCC and have typical circadian rhythms; the expression of major circadian clock genes was also determined. HCC produced a dramatic decrease in the expression of core clock genes, circadian locomotor output cycles kaput (Clock) and brain and muscle Arnt-like protein 1 (Bmal1), and decreased the expression of the clock feedback control genes, Periods (Per1, Per2) and Cryptochromes (Cry1, Cry2). On the other hand, the expression of clock target genes nuclear orphan receptor factor protein (Nr1d1) and D-box-binding protein (Dbp) was upregulated as compared with Peri-HCC and normal livers. Peri-HCC also had mild alterations in these gene expressions. In summary, the present study clearly demonstrated the dysregulation of MTs and circadian clock genes in human HCC, which could provide the information of targeting MT and circadian clock in HCC management.

Association between Interleukin-18 Polymorphisms and Hepatocellular Carcinoma Occurrence and Clinical Progression

We investigated the association between interleukin-18 (IL-18) polymorphisms and the susceptibility and clinicopathological state of hepatocellular carcinoma (HCC). In total, 901 participants, including 559 healthy controls and 342 patients with HCC, were recruited. The allelic discrimination of -607A/C (rs1946518) and -137G/C (rs187238) polymorphisms of IL-18 was assessed through real-time polymerase chain reaction by performing the TaqMan assay. The IL-18 -137G/C polymorphism but not the -607A/C polymorphism showed a significant association with the risk of HCC. Participants carrying the IL-18 -137 polymorphism with heterozygous G/C and homozygous CC genotypes showed a 1.987-fold increase (95% CI = 1.301-3.032; p = 0.001) in the risk of HCC compared with those homozygous for wild-type G/G. The 342 patients with HCC carrying the IL-18 -137G/C polymorphism were positive for hepatitis B virus (HBV) infection with an adjusted odds ratio of 1.668. Moreover, the 142 HBV positive patients with HCC and the IL-18 -137 polymorphism were positive for at least one C genotype and showed significant vascular invasion (p = 0.018). Furthermore, the level of α-fetoprotein was high in the patients carrying the IL-18 -137 polymorphism with GC+CC alleles (p = 0.011). In conclusion, the IL-18 -137G/C polymorphism with a GC+CC genotype could be a factor that increases the risk of HCC. Furthermore, the correlation between the IL-18 -137G/C polymorphism and HCC-related HBV infection is a risk factor for vascular invasion and has a synergistic effect that can further enhance HCC prognosis.

Association of intercellular adhesion molecule-1 single nucleotide polymorphisms with hepatocellular carcinoma susceptibility and clinicopathologic development

Intercellular adhesion molecule-1 (ICAM-1) is a human protein encoded by the ICAM-1 gene and is typically expressed on endothelial cells and immune cells. ICAM-1 is associated with episode, growth, invasion, and metastasis of hepatocellular carcinoma (HCC). However, the association between ICAM-1 genetic variants and the risk of HCC is undetermined. In this study, we investigated the potential associations of ICAM-1 single nucleotide polymorphisms (SNPs) with susceptibility to HCC and its clinicopathological characteristics. A total of 918 participants, including 613 controls participants and 305 patients with HCC, were selected for the analysis of ICAM-1 SNPs (rs3093030, rs5491, rs281432, and rs5498) by using real-time PCR genotyping. After adjusting for covariants of age, sex, and alcohol consumption, 125 smoker patients with HCC carrying at least one G genotype (AG and GG) in rs5498 were observed to have a higher HCC risk compared with 231 smoker control participants carrying the wild-type allele AA (adjusted odds ratio (AOR), 1.713; 95 % confidence interval (CI), 1.091-2.690; P = 0.019). However, patients who possess at least one polymorphic allele of rs5498 are less prone to develop vascular invasive (AOR, 0.309; 95 % CI, 0.103-0.926; P = 0.036). The results suggest that the genetic polymorphism in ICAM-1 rs5498 SNPs with genotype AG and GG is associated with HCC risk among smokers. Moreover, gene and environment interactions of ICAM-1 rs5498 polymorphisms might alter susceptibility to liver cancer. Therefore, ICAM-1 rs5498 may serve as a marker to predict the vascular invasion risk in smoker patients with HCC.

Impact of metallothionein gene polymorphisms on the risk of lung cancer in a Japanese population

Metallothioneins (MTs) are cysteine-rich proteins that act as antioxidants. A case-control study was conducted to assess the effects of gene polymorphisms in the MT region on the risk of lung cancer in Japanese subjects: 769 lung cancer cases and 939 non-cancer controls. Associations were evaluated using logistic regression models with adjustment for potential confounders (age, sex, and lifestyle factors including smoking, drinking, and green-yellow vegetable intake). We found five polymorphisms in the MT-1 gene region that showed statistically significant associations with lung cancer. Of these polymorphisms, rs7196890 showed the strongest association (odds ratio: 1.30, P = 0.004, 95% confidence interval: 1.09-1.55). The impact of the polymorphism decreased with the increase of smoking, and virtually no association with lung cancer was observed among heavy smokers whose pack-year values were 30 or more (odds ratio: 1.02, P = 0.93, 95% confidence interval: 0.67-1.55). These results suggest that polymorphisms in the MT gene are moderately associated with the risk of lung cancer and that the associations are modified by lifestyle factors.

Metallothionein polymorphisms in pathological processes

Metallothioneins (MTs) are a class of metal-binding proteins characterized by a high cysteine content and low molecular weight. MTs play an important role in metal metabolism and protect cells against the toxic effects of radiation, alkylating agents and oxygen free radicals. The evidence that individual genetic characteristics of MTs play an important role in physiological and pathological processes associated with antioxidant defense and detoxification inspired targeted studies of genetic polymorphisms in a clinical context. In recent years, common MT polymorphisms were identified and associated with, particularly, western lifestyle diseases such as cancer, complications of atherosclerosis, and type 2 diabetes mellitus along with related complications. This review summarizes all evidence regarding MT polymorphisms of major human MTs (MT1, MT2, MT3 and MT4), their relation to pathological processes, and outlines specific applications of MTs as a set of genetic markers for certain pathologies.

Metallothioneins and digestive system tumors

Metallothioneins (MTs) are low-molecular weight, cysteine-rich, intracellular metal-binding proteins involved in diverse functions, such as metal homeostasis and/or detoxification, scavenging free radicals and stress response. Recent studies show that MTs play an important role in cell differentiation, proliferation and carcinogenesis by displaying different expression patterns and through different signaling pathways, have important value for the clinical diagnosis, treatment and prognosis of tumors, and can be used as a cancer biomarker. This article aims to discuss the research progress in MTs as a cancer maker in human digestive system tumors.