Effects of polymorphisms in alcohol metabolism and oxidative stress genes on survival from head and neck cancer

ALDH2 mutations and defense against genotoxic aldehydes in cancer and inherited bone marrow failure syndromes

Reactive aldehydes, for instance, formaldehyde and acetaldehyde, are important endogenous or environmental mutagens by virtue of their abilities to produce a DNA lesion called interstrand crosslink (ICL). Aldehyde-metabolizing enzymes such as aldehyde dehydrogenases (ALDHs) and the Fanconi anemia (FA) pathway constitute the main defense lines against aldehyde-induced genotoxicity. Biallelic mutations of genes in any one of the FA complementation groups can impair the ICL repair mechanism and cause FA, a heterogeneous disorder manifested by bone marrow failure (BMF), congenital abnormality and a strong predisposition to cancer. The defective ALDH2 polymorphism rs671 (ALDH2*2) is a known risk and prognostic factor for alcohol drinking-associated cancers. Recent studies suggest that it also promotes BMF and cancer development in FA, and its combination with alcohol dehydrogenase 5 (ADH5) mutations causes aldehyde degradation deficiency syndrome (ADDS), also known by its symptoms as aplastic anemia, mental retardation, and dwarfism syndrome. ALDH2*2 and another pathogenic variant in the alcohol-metabolizing pathway, ADH1B1*1, is prevalent among East Asians. Also, other ALDH2 genotypes with disease-modifying potentials have lately been identified in different populations. Therefore, it would be appropriate to summarize current knowledge of genotoxic aldehydes and defense mechanisms against them to shed new light on the pathogenic effects of ALDH2 variants together with other genetic and environmental modifiers on cancer and inherited BMF syndromes. Lastly, we also presented potential treatment strategies for FA, ADDS and cancer based on the manipulation of aldehyde-induced genotoxicity.

The association between the Mediterranean Diet Score and death from cancer of the head and neck

PURPOSE

The association between diet quality, captured by the Mediterranean Diet Score (MDS), and mortality was studied among 1184 individuals diagnosed with head and neck cancer (HNC) who reflected on the year preceding diagnosis about their usual diet using National Cancer Institute's Diet History Questionnaire (DHQ).

METHODS

Intakes of nine dietary components were scored and summed to construct the MDS (sample: median = 4; range (0-9); lower MDS reflected poorer diet quality; 5-year survival probability = 0.62). Cox regression estimated 5-year hazard ratios (HR) and 95% confidence intervals (95CI) for all-cause mortality and for HNC-specific death for contrasts of MDS quintiles. Effect measure modification (EMM) by tumor features [human papillomavirus (HPV) positivity; anatomic site] and sociodemographic behavioral factors [race, body mass index (BMI), smoking, alcohol consumption] was explored.

RESULTS

The 5-year [HR (95CI); P-trend] for all-cause mortality and HNC-specific mortality for highest versus lowest MDS quintile contrasts were [0.51 (0.33, 0.80); 0.014] and [0.43 (0.22, 0.85); 0.004], respectively. A unit increase in MDS adherence resulted in a 15% reduction of the 5-year HR for HNC-specific death for tumors located at the oral cavity [HR (95CI): 0.85 (0.75, 0.96)]. Poor diet quality (MDS ≤ 4) interacted with lower BMI (kg/m2 < 25) and separately with ever-using alcohol to produce 5-year HRs for all-cause and HNC-specific mortality that were statistically significantly larger than the sum of the individual HRs representing each combination (Poor diet quality + lower BMI; Poor diet quality + ever-using alcohol).

CONCLUSION

Greater adherence to a Mediterranean diet pattern prior to HNC diagnosis may reduce post-diagnosis mortality.

Impact of Alcohol Dehydrogenase 7 Polymorphism and Alcohol Consumption on Risk of Head and Neck Squamous Cell Carcinoma: A Korean Case-Control Study

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is closely associated with alcohol consumption and individual genetic susceptibility, such as single nucleotide polymorphism (SNP) of alcohol dehydrogenase (ADH). This study aimed to investigate the association of ADH7 SNPs with the risk of HNSCC.

METHODS

We analyzed ADH7 rs1573496C>G, rs3737482T>C, rs1154460G>A, and rs284787T>C SNPs in 250 patients with HNSCC and 322 controls in the Korean populations. Genotyping was conducted using the TaqMan assay. Linkage disequilibrium and haplotypes were analyzed.

RESULTS

The odds ratios (OR) and 95% confidence intervals (CI) of the CT and CC genotypes of ADH7 rs3737482T>C were 0.48 (0.29-0.78) and 0.69 (0.49-0.96), indicating a significantly decreased risk. In SNP of rs1154460G>A, the OR and 95% CI of the AA genotype was 1.63 (1.11-2.40), showing a significant increase in the risk. Furthermore, SNPs of ADH7 rs3737482T>C and ADH7 rs1154460G>A exhibit synergistic interactions with alcohol composition on the risk of HNSCC. None of the haplotypes were associated with the risk of HNSCC.

CONCLUSIONS

ADH7 rs3737482T>C and rs1154460G>A SNPs are associated with the risk of development of HNSCC in Koreans. They could serve as molecular biological markers to screen high-risk groups for HNSCC.

Genetic variations in the drug metabolizing enzyme, CYP2E1, among various ethnic populations of Pakistan

Genetic polymorphism in cytochrome P450 (CYP) monooxygenase genes is an important source of interindividual variability of drug response. CYP enzyme activities may change as a result of such polymorphisms which then, may affect drug metabolism. This would result in a change in the severity and frequency of adverse effects in addition to the non-responder phenomenon. CYP2E1, a member of CYP superfamily, affects the metabolism of several clinically important drugs such as halothane, paracetamol, etc. Genetic variation in CYP2E1 is known to cause significant inter-individual differences in drug response and adverse effects. The degree of genetic variation is found to be different in different populations around the world. The frequencies of two important polymorphisms in the CYP2E1*7C, NC_000010.10:g.135340548A>G (rs2070672) and CYP2E1, NC_000010.10:g.135339244G>C (rs3813865), are not known in the Pakistani population. In the present investigation, 636 healthy human volunteers were screened for these two single nucleotide polymorphism. Our results indicate that about 18% (rs2070672) and 28% (rs3813865) of the Pakistani population has a genotype containing at least one low activity allele. A significant interethnic variation in the frequencies of both the polymorphisms was observed. These results suggest that pharmacogenetics screening for low activity genotypes would be a helpful tool for clinicians when they prescribe medications metabolized by CYP2E1, as a significant fraction of the Pakistani population is expected to have a variable response to these drugs.

Cytochrome P450 2E1 and its roles in disease

Cytochrome P450 (P450) 2E1 is the major P450 enzyme involved in ethanol metabolism. That role is shared with two other enzymes that oxidize ethanol, alcohol dehydrogenase and catalase. P450 2E1 is also involved in the bioactivation of a number of low molecular weight cancer suspects, as validated in vivo in mouse models where cancers could be attenuated by deletion of Cyp2e1. P450 2E1 does not have a role in global production of reactive oxygen species but localized roles are possible, e.g. in mitochondria. The structures, conformations, and catalytic mechanisms of P450 2E1 have some unusual features among P450s. The concentration of hepatic P450 varies ≥10-fold among humans, possibly in part due to single nucleotide variants. The level of P450 2E1 may have relevance in the rates of oxidation of drugs, particularly acetaminophen and anesthetics.

The association between diet quality and cancer incidence of the head and neck

The association between diet quality and head and neck cancer (HNC) was explored using a population-based case-control study of 1170 HNC cases and 1303 age-, race-, and sex-matched controls from the United States. Diet quality was assessed with three diet quality scores (DQS): (a) Healthy Eating Index 2005 (HEI-2005), (b) Mediterranean Diet Score (MDS), and (c) HNC-specific Mediterranean Diet Score (MDS-HNC), a modified MDS that we developed to be more applicable to HNC. Logistic regression models estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) representing diet quality-incident HNC associations. We examined effect measure modification (EMM) by body mass index (BMI), race, cigarette smoking, and alcohol consumption and associational heterogeneity by HPV-positivity and tumor site. A one standard deviation summary DQS decrement suggested a consistent inverse association (ORs (CIs)) for the HEI-2005, MDS, and MDS-HNC: 1.35 (1.21, 1.50), 1.13 (1.02, 1.25), and 1.17 (1.06, 1.31), respectively. This association did not vary by tumor site or tumor HPV status, though additive EMM by alcohol use and by BMI was observed. Our findings suggest the Mediterranean diet can be used to study HNC in American populations, and that poor diet quality elevates HNC incidence, particularly among alcohol users.

A Bayesian Sensitivity Analysis to Partition Body Mass Index Into Components of Body Composition: An Application to Head and Neck Cancer Survival

Previous studies have suggested a "J-shaped" relationship between body mass index (BMI, calculated as weight (kg)/height (m)2) and survival among head and neck cancer (HNC) patients. However, BMI is a vague measure of body composition. To provide greater resolution, we used Bayesian sensitivity analysis, informed by external data, to model the relationship between predicted fat mass index (FMI, adipose tissue (kg)/height (m)2), lean mass index (LMI, lean tissue (kg)/height (m)2), and survival. We estimated posterior median hazard ratios and 95% credible intervals for the BMI-mortality relationship in a Bayesian framework using data from 1,180 adults in North Carolina with HNC diagnosed between 2002 and 2006. Risk factors were assessed by interview shortly after diagnosis and vital status through 2013 via the National Death Index. The relationship between BMI and all-cause mortality was convex, with a nadir at 28.6, with greater risk observed throughout the normal weight range. The sensitivity analysis indicated that this was consistent with opposing increases in risk with FMI (per unit increase, hazard ratio = 1.04 (1.00, 1.08)) and decreases with LMI (per unit increase, hazard ratio = 0.90 (0.85, 0.95)). Patterns were similar for HNC-specific mortality but associations were stronger. Measures of body composition, rather than BMI, should be considered in relation to mortality risk.

Long-term Survival in Head and Neck Cancer: Impact of Site, Stage, Smoking, and Human Papillomavirus Status

OBJECTIVES/HYPOTHESIS

Literature examining long-term survival in head and neck squamous cell carcinoma (HNSCC) with human papillomavirus (HPV) status is lacking. We compare 10-year overall survival (OS) rates for cases to population-based controls.

STUDY DESIGN

Prospective cohort study.

METHODS

Cases surviving 5 years postdiagnosis were identified from the Carolina Head and Neck Cancer Study. We examined 10-year survival by site, stage, p16, and treatment using Kaplan-Meier and Cox proportional hazard models. Cases were compared to age-matched, noncancer controls with stratification by p16 and smoking status.

RESULTS

Ten-year OS for HNSCC is less than controls. In 581 cases, OS differed between sites with p16+ oropharynx having the most favorable prognosis (87%), followed by oral cavity (69%), larynx (67%), p16- oropharynx (56%), and hypopharynx (51%). Initial stage, but not treatment, also impacted OS. When compared to controls matched on smoking status, the hazard ratio (HR) for death in p16+ oropharynx cases was 1.5 (95% confidence interval [CI]: 0.7-3.1) for smokers and 2.4 (95% CI: 0.7-8.8) for nonsmokers. Similarly, HR for death in non-HPV-associated HNSCC was 2.2 (95% CI: 1.7-3.0) for smokers and 2.4 (95% CI: 1.4-4.9) for nonsmokers.

CONCLUSIONS

OS for HNSCC cases continues to decrease 5 years posttreatment, even after stratification by p16 and smoking status. Site, stage, smoking, and p16 status are significant factors. These data provide important prognostic information for HNSCC.

LEVEL OF EVIDENCE

2 Laryngoscope, 129:2506-2513, 2019.

Ursodeoxycholic acid is a GPBAR1 agonist and resets liver/intestinal FXR signaling in a model of diet-induced dysbiosis and NASH

Obeticholic acid (OCA) is a farnesoid-X-receptor (FXR) ligand, shown effective in reducing steatosis and fibrosis in NASH patients. However, OCA causes major side effects including pruritus, while increases the risk for liver decompensation in cirrhotic patients. Ursodeoxycholic acid (UDCA), is a safe and unexpensive bile acid used in the treatment of liver disorders whose mechanism of action is poorly defined. Here we have compared the effects of OCA and UDCA in a mouse model of NASH. In mice exposed to a diet rich in fat/cholesterol and fructose (HFD-F), treatment with OCA or UDCA effectively prevented body weight gain, insulin resistance, as demonstrated by OGTT, and AST plasma levels. After 12 weeks HFD-F mice developed liver microvesicular steatosis, inflammation and mild fibrosis, increased expression of inflammatory (TNFα, IL6, F4/80) and fibrosis (αSma, Col1α1, Tgfβ) markers, reduced liver expression of FXR, dysregulated liver FXR signaling and elevated levels of Tauro-α and β-muricholic acid (T-α and βMCA), two FXR antagonists in mice. Both compounds prevented these changes and improved liver histopathology. OCA reduced primary bile acid synthesis worsening the T-CA/T-βMCA ratio. UDCA effectively transactivated GPBAR1 in vitro. By RNAseq analysis we found that among over 2400 genes modulated by the HFD-F, only 32 and 60 genes were modulated by OCA and UDCA, with only 3 genes (Dbp, Adh7, Osgin1) being modulated by both agents. Both agents partially prevented the intestinal dysbiosis. CONCLUSIONS: UDCA is a GPBAR1 ligand and exerts beneficial effects in a rodent model of NASH by activating non-overlapping pathway with OCA.

Transcriptome analysis and prognosis of ALDH isoforms in human cancer

Overexpression of ALDH is associated with cancer stem-like features and poor cancer prognosis. High ALDH activity has been observed in cancer stem-like cells. There are a total of 19 human ALDH isoforms, all of which are associated with reducing oxidative stress and protecting cells from damage. However, it is unknown whether all ALDHs are associated with poor cancer prognosis and which ones play a significant role in cancer progression. In this study, we used RNA sequencing data from The Cancer Genome Atlas (TCGA) to evaluate the differential expression of 19 ALDH isoforms in 5 common human cancers. The 19 ALDH genes were analyzed with an integrating meta-analysis of cancer prognosis. Genotyping and next-generation RNA sequencing for 30 pairwise samples of head and neck squamous cell carcinoma were performed and compared with the TCGA cohort. The analysis showed that each ALDH isoform had a specific differential expression pattern, most of which were related to prognosis in human cancer. A lower expression of ALDH2 in the tumor was observed, which was independent from the ALDH2 rs671 SNP variant and the expression of other mitochondria-associated protein coding genes. This study provides new insight into the association between ALDH expression and cancer prognosis.

Clinical features and prognostic factors in patients with head and neck cancer: Results from a multicentric study

BACKGROUND

The purpose of this study is to evaluate whether demographics, lifestyle habits, clinical data and alcohol dehydrogenase polymorphisms rs1229984 and rs1573496 associated with first primary head and neck (HNC) are associated with overall survival, recurrence, and second primary cancer (SPC).

METHODS

We conducted a follow-up study in five centres including 801 cases. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated for overall survival, recurrence and SPC.

RESULTS

Five-years overall survival was 62% for HNC cases, 55% for oral cavity, 53% for oropharynx, 41% for hypopharynx, and 71% for larynx. Predictors of survival were older ages (HR=1.18 for 5 years increase; CI: 1.07-1.30), higher tumour stage (HR=4.16; CI: 2.49-6.96), and high alcohol consumption (HR=3.93; CI: 1.79-8.63). A combined therapy (HR=3.29; CI: 1.18-9.13) was associated with a worst prognosis for oral cavity cancer. The only predictor was higher tumour stage (HR=2.25; CI: 1.26-4.03) for recurrence, and duration of smoking (HR=1.91; CI: 1.00-3.68) for SPC. ADH1B rs1229984 polymorphism HRs for HNC and oesophageal cancer death and for alcohol related cancer death were 0.67 (95% CI: 0.42-1.08), and 0.64 (95% CI: 0.40-1.03), respectively.

CONCLUSIONS

The survival expectation differs among HNC sites. Increasing age and stage, and high alcohol consumption were unfavourable predictors of HNC survival overall. Duration of tobacco consumption before the first primary tumour was a risk factor for SPC.

Single nucleotide polymorphisms in nucleotide excision repair genes, cancer treatment, and head and neck cancer survival

PURPOSE

Head and neck cancers (HNC) are commonly treated with radiation and platinum-based chemotherapy, which produce bulky DNA adducts to eradicate cancerous cells. Because nucleotide excision repair (NER) enzymes remove adducts, variants in NER genes may be associated with survival among HNC cases both independently and jointly with treatment.

METHODS

Cox proportional hazards models were used to estimate race-stratified (White, African American) hazard ratios (HRs) and 95 % confidence intervals for overall (OS) and disease-specific (DS) survival based on treatment (combinations of surgery, radiation, and chemotherapy) and 84 single nucleotide polymorphisms (SNPs) in 15 NER genes among 1,227 HNC cases from the Carolina Head and Neck Cancer Epidemiology Study.

RESULTS

None of the NER variants evaluated were associated with survival at a Bonferroni-corrected alpha of 0.0006. However, rs3136038 [OS HR = 0.79 (0.65, 0.97), DS HR = 0.69 (0.51, 0.93)] and rs3136130 [OS HR = 0.78 (0.64, 0.96), DS HR = 0.68 (0.50, 0.92)] of ERCC4 and rs50871 [OS HR = 0.80 (0.64, 1.00), DS HR = 0.67 (0.48, 0.92)] of ERCC2 among Whites, and rs2607755 [OS HR = 0.62 (0.45, 0.86), DS HR = 0.51 (0.30, 0.86)] of XPC among African Americans were suggestively associated with survival at an uncorrected alpha of 0.05. Three SNP-treatment joint effects showed possible departures from additivity among Whites.

CONCLUSIONS

Our study, a large and extensive evaluation of SNPs in NER genes and HNC survival, identified mostly null associations, though a few variants were suggestively associated with survival and potentially interacted additively with treatment.