Diarylheptanoid 35d overcomes EGFR TKI resistance by inducing hsp70-mediated lysosomal degradation of EGFR in EGFR-mutant lung adenocarcinoma.

Epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma (LUAD) patients often respond to EGFR tyrosine kinase inhibitors (TKIs) initially but eventually develop resistance to TKIs. The switch of EGFR downstream signaling from TKI-sensitive to TKI-insensitive is a critical mechanism-driving resistance to TKIs. Identification of potential therapies to target EGFR effectively is a potential strategy to treat TKI-resistant LUADs. In this study, we developed a small molecule diarylheptanoid 35d, a curcumin derivative, that effectively suppressed EGFR protein expression, killed multiple TKI-resistant LUAD cells in vitro, and suppressed tumor growth of EGFR-mutant LUAD xenografts with variant TKI-resistant mechanisms including EGFR C797S mutations in vivo. Mechanically, 35d triggers heat shock protein 70-mediated lysosomal pathway through transcriptional activation of several components in the pathway, such as HSPA1B, to induce EGFR protein degradation. Interestingly, higher HSPA1B expression in LUAD tumors associated with longer survival of EGFR-mutant, TKI-treated patients, suggesting the role of HSPA1B on retarding TKI resistance and providing a rationale for combining 35d with EGFR TKIs. Our data showed that combination of 35d significantly inhibits tumor reprogression on osimertinib and prolongs mice survival. Overall, our results suggest 35d as a promising lead compound to suppress EGFR expression and provide important insights into the development of combination therapies for TKI-resistant LUADs, which could have translational potential for the treatment of this deadly disease.

TIMP3 Gene Polymorphisms of -1296 T > C and -915 A > G Increase the Susceptibility to Arsenic-Induced Skin Cancer: A Cohort Study and In Silico Analysis of Mutation Impacts

Long-term exposure to arsenic may induce several human cancers, including non-melanoma skin cancer. The tissue inhibitor of metalloproteinase (TIMP)-3, encoded by the TIMP3 gene, may inhibit tumor growth, invasion, and metastasis of several cancer types. In this study, we aimed to investigate effects of the TIMP3 -1296 T > C (rs9619311) and -915 A > G (rs2234921) single-nucleotide polymorphisms (SNPs) on skin cancer risk in an arsenic-exposed population, and to evaluate the influence of allele-specific changes by an in silico analysis. In total, 1078 study participants were followed up for a median of 15 years for newly diagnosed skin cancer. New cases were identified through linkage to the National Cancer Registry of Taiwan. A Cox regression analysis was used to evaluate the effects of TIMP3 variants. Transcription factor (TF) profiling of binding sites of allele-specific changes in SNPs was conducted using the JASPAR scan tool. We observed borderline associations between TIMP3 genotypes and skin cancer risk. However, when combined with high arsenic exposure levels, the rs9619311 C allele, rs2234921 G allele, or C-G haplotype groups exhibited a greater risk of developing skin cancer compared to the respective common homozygous genotype group. The in silico analysis revealed several TF motifs located at or flanking the two SNP sites. We validated that the C allele of rs9619311 attenuated the binding affinity of BACH2, MEIS2, NFE2L2, and PBX2 to the TIMP3 promoter, and that the G allele of rs2234921 reduced the affinity of E2F8 and RUNX1 to bind to the promoter. Our findings suggest significant modifications of the effect of the association between arsenic exposure and skin cancer risk by the TIMP3 rs9619311 and rs2234921 variants. The predicted TFs and their differential binding affinities to the TIMP3 promoter provide insights into how TIMP3 interacts with arsenic through TFs in skin cancer formation.

Risk Prediction Models for Patients with Head and Neck Cancer among the Taiwanese Population.

Epidemiological evidence has suggested that modifiable lifestyle factors play a significant role in the risk of head and neck cancer (HNC). However, few studies have established risk prediction models of HNC based on sex and tumor subsites. Therefore, we predicted HNC risk by creating a risk prediction model based on sex- and tumor subsites for the general Taiwanese population. This study adopted a case-control study design, including 2961 patients with HNC and 11,462 healthy controls. Multivariate logistic regression and nomograms were used to establish HNC risk prediction models, which were internally validated using bootstrap sampling. The multivariate logistic regression model indicated that age, education level, alcohol consumption, cigarette smoking, passive smoking, coffee consumption, and body mass index are common HNC predictors in both sexes, while the father's ethnicity, betel-nut-chewing habits, and tea consumption were male-specific HNC predictors. The risk factors of the prediction model for the HNC tumor subsite among men were the same as those for all patients with HNC. Additionally, the risks of alcohol consumption, cigarette smoking, and betel nut chewing varied, based on the tumor subsite. A c-index ranging from 0.93 to 0.98 indicated that all prediction models had excellent predictive ability. We developed several HNC risk prediction models that may be useful in health promotion programs.

The Association of Erythropoietin and Age-Related Macular Degeneration in Hemodialysis Patients: A Nationwide Population-Based Cohort Study.

This population-based retrospective cohort study investigated the effectiveness of erythropoietin (EPO) treatment in reducing the risk of age-related macular degeneration (AMD) in hemodialysis patients, using the National Health Insurance Research Data of Taiwan. From the database, we identified 147,318 end-stage renal disease (ESRD) patients on hemodialysis who had been diagnosed in 2000−2014 to establish the propensity-score-matched EPO user cohort and non-EPO user cohort with equal sample size of 15,992. By the end of 2016, the cumulative incidence of AMD in EPO users was about 3.29% lower than that in non-EPO users (Kaplan−Meier survival p < 0.0001). The risk of AMD was 43% lower in EPO users than in non-EPO users, with an adjusted hazard ratio (aHR) of 0.57 (95% confidence interval (CI) = 0.51−0.64) estimated in the multivariate Cox model. A significant negative dose−response relationship was identified between the EPO dosage and the risk of AMD (p < 0.0001). Another beneficial effect of EPO treatment was a reduced risk of both exudative AMD (aHR = 0.48, 95% CI = 0.40−0.61) and non-exudative AMD (aHR = 0.61, 95% CI = 0.53−0.69), also in similar dose−response relationships (p < 0.0001). Our findings suggest that EPO treatment for hemodialysis patients could reduce AMD risk in a dose−response relationship.

GT-Repeat Polymorphism in the HO-1 Gene Promoter Is Associated with Risk of Liver Cancer: A Follow-Up Study from Arseniasis-Endemic Areas in Taiwan.

The induction of heme oxygenase-1 (HO-1) has been shown to have therapeutic potential in experimental models of hepatitis and liver fibrosis, which are closely related to liver cancer. In humans, HO-1 induction is transcriptionally modulated by the length of a GT-repeat [(GT)n] in the promoter region. We aimed to investigate the effect of HO-1 (GT)n variants on liver cancer in a human population. We determined the HO-1 genotype in 1153 study subjects and examined their association with liver cancer risk during a 15.9-year follow-up. Allelic polymorphisms were classified as short [S, <27 (GT)n] or long [L, ≥27 (GT)n]. Newly developed cancer cases were identified through linkage to the National Cancer Registry of Taiwan. Multivariate Cox regression analysis was used to evaluate the effect of the HO-1 (GT)n variants. Alpha-fetoprotein (AFP) and cirrhosis history were also examined. The S/S genotype was found to be significantly associated with liver cancer risk, compared to the L/S and L/L genotypes. The S/S genotype group also had a higher percentage of subjects with abnormal AFP levels than other groups. There were significant percentages of cirrhosis among groups who carried S-alleles. Our findings indicate that short (GT)n variants in the HO-1 gene may confer susceptibility to rather than protection from liver cirrhosis/cancer.

Analysis of Different Types of Interferon-Associated Retinopathy in Patients with Chronic Hepatitis C Virus Infection Treated with Pegylated Interferon Plus Ribavirin.

This retrospective cohort study aims to investigate interferon (IFN)-associated retinopathy incidence in patients with chronic hepatitis C virus (HCV) infection treated with pegylated interferon (PegIFN) plus ribavirin (RBV). We selected 1688 patients undergoing PegIFN/RBV therapy for HCV (HCV-treated cohort), 3376 patients not receiving HCV treatment (HCV-untreated cohort) and 16,880 controls without HCV (non-HCV cohort) from the Taiwan Longitudinal Health Insurance Database. The patients were frequency-matched by age, sex, and index date at a 1:2:10 ratio, and followed up until the end of 2013. Cox proportional hazard regression models were used to compare the incidences of any retinal vascular events, including subtypes, among the three cohorts. Compared with the non-HCV cohort, the HCV-treated cohort had a significantly increased risk of retinopathy (hazard ratio (HR) = 4.98, 95% confidence interval (CI): 2.02-12.3). The risk was particularly prominent for retinal hemorrhage (HR = 12.7, 95% CI: 3.78-42.9). When the HCV-untreated cohort was used as the reference, the aforementioned HRs increased to 9.02 (95% CI: 3.04-26.8) and 32.3 (95% CI: 3.94-265), respectively. This study suggested that PegIFN/RBV therapy significantly increased the risk of retinal hemorrhage but not retinal vascular occlusions in the HCV-treated cohort.

Increased Risk of Age-Related Macular Degeneration with Chronic Hepatitis C Virus Infection: A Nationwide Population-Based Propensity Score-Matched Cohort Study in Taiwan.

Studies evaluating the association between age-related macular degeneration (AMD) risk and HCV infection are scant. In this population-based cohort study, 13,300 patients newly diagnosed as having HCV (HCV cohort) and 26,600 propensity score-matched patients without HCV (non-HCV cohort) were identified from the Taiwan National Health Insurance Research Database between 2000 and 2013. Furthermore, 1,983 patients with HCV who received pegylated interferon and ribavirin treatment (HCV-treated cohort) and propensity score-matched patients with HCV (matched at a ratio of 1:2) who did not receive this treatment (HCV-untreated cohort) were selected from the HCV cohort. Cox proportional hazards regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) associated with the risk of AMD in the HCV and non-HCV cohorts. The adjusted HR (aHR) for AMD in the HCV cohort was 1.22 (95% CI = 1.09-1.35). This significant association was observed only for nonexudative AMD (aHR = 1.22, 95% CI = 1.09-1.37). Compared with the HCV-untreated cohort, the HCV-treated cohort showed no significant association with any type of AMD (aHR = 1.07, 95% CI = 0.81-1.43). Age and sex did not modify AMD development after the exposure and treatment of chronic HCV infection. Our findings revealed that patients with chronic HCV infection had an increased risk of AMD.

IFIT1 and IFIT3 promote oral squamous cell carcinoma metastasis and contribute to the anti-tumor effect of gefitinib via enhancing p-EGFR recycling.

IFIT1 and IFIT3 are abundant products of interferon-stimulating genes. While the importance of IFIT1 and IFIT3 in the prognosis of cancer has been reported, the molecular basis of IFIT1 and IFIT3 in cancer progression remains unexplored. In the present study, we investigated the modes of action and the clinical significance of IFIT1 and IFIT3 in oral squamous cell carcinoma (OSCC). Ectopic expression of IFIT1 or IFIT3 induced OSCC cell invasion by promoting the epithelial-mesenchymal transition, whereas IFIT1 or IFIT3 knockdown exhibited opposite effects. Overexpression of IFIT1 or IFIT3 promoted tumor growth, regional and distant metastasis in xenograft and orthotopic nude mice models. Most importantly, IFIT1 or IFIT3 overexpression increased the levels of p-EGFRY1068 and p-AKTS473 in OSCC cells and also enhanced tumor inhibitory effect of gefitinib. By immunoprecipitation and LC-MS/MS analysis, we found that IFIT1 and IFIT3 interacted with ANXA2 that enhanced p-EGFRY1068 endosomal recycling. Depletion of ANXA2 using siRNA therefore abolished p-EGFRY1068 and p-AKTS473 expression in IFIT1- or IFIT3-overexpressed cells. Furthermore, a significant positive association of increased IFIT1 and IFIT3 expression with advanced T-stage, lymph node metastasis, perineural invasion, lymphovascular invasion, extranodal extension, and poor overall survival rate was confirmed in OSCC patients. We also found a statistically positive correlation of p-EGFRY1068 expression with IFIT1 and IFIT3 in OSCC tumors and poor clinical outcome in patients. Collectively, we demonstrated a novel role of IFIT1 and IFIT3 in driving OSCC progression and metastasis by interacting with ANXA2 and hence enhancing p-EGFR recycling and its downstream signaling.

Emerging Functions of Human IFIT Proteins in Cancer.

Interferon-induced protein with tetratricopeptide repeats (IFIT) genes are prominent interferon-stimulated genes (ISGs). The human IFIT gene family consists of four genes named IFIT1, IFIT2, IFIT3, and IFIT5. The expression of IFIT genes is very low in most cell types, whereas their expression is greatly enhanced by interferon treatment, viral infection, and pathogen-associated molecular patterns (PAMPs). The proteins encoded by IFIT genes have multiple tetratricopeptide repeat (TPR) motifs. IFIT proteins do not have any known enzymatic roles. However, they execute a variety of cellular functions by mediating protein-protein interactions and forming multiprotein complexes with cellular and viral proteins through their multiple TPR motifs. The versatile tertiary structure of TPR motifs in IFIT proteins enables them to be involved in distinct biological functions, including host innate immunity, antiviral immune response, virus-induced translation initiation, replication, double-stranded RNA signaling, and PAMP recognition. The current understanding of the IFIT proteins and their role in cellular signaling mechanisms is limited to the antiviral immune response and innate immunity. However, recent studies on IFIT protein functions and their involvement in various molecular signaling mechanisms have implicated them in cancer progression and metastasis. In this article, we focused on critical molecular, biological and oncogenic functions of human IFIT proteins by reviewing their prognostic significance in health and cancer. Research suggests that IFIT proteins could be novel therapeutic targets for cancer therapy.

Arsenic Exposure From Drinking Water and the Incidence of CKD in Low to Moderate Exposed Areas of Taiwan: A 14-Year Prospective Study.

BACKGROUND: Arsenic exposure is associated with decreased kidney function. The association between low to moderate arsenic exposure and kidney disease has not been fully clarified. STUDY DESIGN: The association between arsenic exposure from drinking water and chronic kidney disease (CKD) was examined in a long-term prospective observational study. SETTING & PARTICIPANTS: 6,093 participants 40 years and older were recruited from arseniasis-endemic areas in northeastern Taiwan. Arsenic levels were 28.0, 92.8, and 295.7µg/L at the 50th, 75th, and 90th percentiles, respectively. PREDICTOR: Well-water arsenic and urinary total arsenic (inorganic plus methylated arsenic species) concentrations, adjusted for urinary creatinine concentration. OUTCOMES: Kidney diseases (ICD-9 codes: 250.4, 274.1, 283.11, 403.*1, 404.*2, 404.*3, 440.1, 442.1, 447.3, or 580-589) and CKD (ICD-9 code: 585) ascertained using Taiwan's National Health Insurance database 1998 to 2011. MEASUREMENTS: HRs contrasting CKD risk across arsenic exposure levels were estimated using Cox regression. Prevalence ORs for proteinuria (protein excretion ≥ 200mg/g) comparing quartiles of total urinary arsenic concentrations were estimated using logistic regression. RESULTS: We identified 1,104 incident kidney disease cases, including 447 CKD cases (incidence rates, 166.5 and 67.4 per 104 person-years, respectively). A dose-dependent association between well-water arsenic concentrations and kidney diseases was observed after adjusting for age, sex, education, body mass index, cigarette smoking, alcohol consumption, and analgesic use. Using arsenic concentration ≤ 10.0µg/L as reference, multivariable-adjusted HRs for incident CKD were 1.12 (95% CI, 0.88-1.42), 1.33 (95% CI, 1.03-1.72), and 1.33 (95% CI, 1.00-1.77) for arsenic concentrations of 10.1 to 49.9, 50.0 to 149.9, and ≥150.0µg/L, respectively (P for trend=0.02). The association between arsenic concentration and kidney diseases was stronger for women (P for interaction=0.06). Arsenic values in the range of 50th to 75th and 75th to 100th percentiles of total urinary arsenic concentrations were associated with 50% and 67% higher prevalences, respectively, of proteinuria. LIMITATIONS: Kidney diseases and CKD outcomes were based on diagnostic codes. Glomerular filtration rates were not available. Other heavy metals were not measured. CONCLUSIONS: This study describes the temporal relationship between arsenic concentrations ≥ 10µg/L in drinking water and CKD. A dose-dependent association between well-water arsenic concentration and kidney diseases was observed. Higher creatinine-adjusted urinary total arsenic concentrations were associated with a higher prevalence of proteinuria.

Promoter hypermethylation of LGALS4 correlates with poor prognosis in patients with urothelial carcinoma.

Galectine-4 (gal-4), encoded by the LGALS4 gene, was recently shown to exhibit a tumor suppressive effect in colorectal carcinoma and pancreatic adenocarcinoma, although how the expression of this gene is regulated remains unknown. No reports describe the significance of gal-4 in the malignant potential of urothelial tumors. Thus, we analyzed LGALS4 methylation and gene expression and their clinical relevance and biological function in urothelial carcinoma (UC). LGALS4 methylation was initially identified as a progression biomarker for UC patients through genome-wide DNA methylation profiling of 16 tumor samples. Bisulfite sequencing PCR and immunohistochemistry were performed to validate the promoter methylation and expression of LGALS4. We used quantitative methylation-specific PCR to determine the methylation levels of LGALS4 normalized to ACTB in the tumor samples of 79 UC patients and compared the levels between patients with different clinicopathological characteristics. The association with survival probability was analyzed with the Kaplan-Meier method and Cox regression analysis. The ectopic expression of gal-4 in cancer cell lines was used to address its biological function in UC in vitro. The promoter hypermethylation of LGALS4 (>2.51, log10 scale) revealed a positive correlation with high levels of both histological grade and tumor T category and with lymph node metastasis (all P≤0.001). In addition, LGALS4 hypermethylation was an independent predictor of inferior survival in UC patients (P<0.05). The ectopic expression studies demonstrated that gal-4 suppressed urothelial cancer cell growth, migration, and invasion. Thus, LGALS4 may function as a tumor suppressor gene in UC progression. Our findings provide evidence that methylation-mediated LGALS4 gene repression may be involved in urothelial tumor progression.

Cumulative arsenic exposure is associated with fungal infections: Two cohort studies based on southwestern and northeastern basins in Taiwan.

Long-term arsenic exposure results in atherosclerosis and cancers, along with aberrant immune responses. Animal-based and epidemiological studies indicate that arsenic exposure increases susceptibility to viral and bacterial infections. This study aimed to assess whether arsenic exposure is associated with the development of fungal infection, which is substantially attributed to as a cause of aberrant immunity. Based on two well-established cohorts from two basins in southwestern (SW; high arsenic area) and northeastern (NE; low arsenic area) Taiwan (n=297 and 2738, respectively), the arsenic exposure in well water was estimated using HPLC-ICP-MS. Fungal infections were defined via clinical and mycological assessments (PCR of fungal 18S rRNA) of nail samples. Individuals in SW cohort with cumulative arsenic exposure >10,000µg/L∗years had a higher risk of developing fungal infections (OR=1.57, 95% CI=1.08-1.92) after adjusting for diabetes and occupation. In NE cohort, female sex, alcohol consumption, and chronic kidney diseases were associated with toenail infections. In contrast, fingernail infections (OR=1.33, 95% CI=1.05-1.68) were highly associated with arsenic exposure in a dose-dependent manner. We are the first to report palmar and plantar hyperkeratosis upon low arsenic exposure in 3.9% and 6.7% individuals, respectively. This is the first large-scale study showing arsenic exposure is associated with fungal infections in a dose-dependent manner.

Effects of Arsenic in Drinking Water on Risk of Hepatitis or Cirrhosis in Persons With and Without Chronic Viral Hepatitis.

BACKGROUND & AIMS: Arsenic in drinking water is associated with hepatomegaly and death from liver cancer. However, confounding factors related to liver diseases have not been carefully studied. We examined associations between exposure of arsenic in drinking water and risk of hepatitis and cirrhosis, and the interaction with chronic viral hepatitis, in people living in the Lanyang Basin of northeastern Taiwan, where well water has an arsenic content that ranges from undetectable to 3590 µg/L. METHODS: We tested blood samples from 4387 people who lived in arseniasis-endemic areas in northeastern Taiwan from 1991 through 1994 for hepatitis B virus DNA, hepatitis B surface antigen (HBsAg), and antibodies against hepatitis C virus (anti-HCV). We measured arsenic concentrations in well water and collected information on residents' histories of major chronic diseases. Reports of chronic hepatitis or cirrhosis were ascertained using the Taiwan National Health Insurance database. Reports of liver cancer were ascertained using the Taiwan National Cancer Registry. RESULTS: Prevalence odds ratios in the overall study population for chronic hepatitis or cirrhosis for well water arsenic concentrations of ≤10 µg/L were 1.00 (reference), 0.93 for 10.1-49.9 µg/L (95% confidence interval [CI], 0.57-1.52), 1.24 for 50.0-99.9 µg/L (95% CI, 0.68-2.23), 0.98 for 100.0-299.9 (95% CI, 0.52-1.85), and 1.86 for ≥300.0 µg/L (95% CI, 1.08-3.20). Increasing levels of arsenic in drinking water were associated with increasing prevalence of chronic hepatitis or cirrhosis in residents who were seronegative for HBsAg and seronegative for anti-HCV, but not for seropositive for either HBsAg or anti-HCV. In individuals who were seropositive for HBsAg or anti-HCV, we observed an inverse association between hepatitis or cirrhosis and consumption of water with levels of arsenic ≥100.0 µg/L. Among participants who were seropositive for HBsAg or anti-HCV, consumption of water with levels of arsenic ≥100.0 µg/L was associated with a reduced risk of liver cancer (multivariate-adjusted hazard ratio, 0.29; 95% CI, 0.09-0.95; P < .05). A higher proportion of individuals exposed to cumulative arsenic level >14,000 µg/L ×year were carriers of inactive hepatitis B virus (DNA <10,000 copies/mL) and were positive for HBsAg (60%) than individuals exposed to water below this arsenic level (35%). CONCLUSIONS: Concentrations of arsenic concentration in drinking water ≥300.0 µg/L significantly increase risk of hepatitis or cirrhosis in people without chronic viral hepatitis. However, in people with chronic viral hepatitis, levels of arsenic ≥100.0 µg/L in drinking water significantly reduce the risk of chronic hepatitis or cirrhosis.

Effect of heme oxygenase-1 gene promoter polymorphism on cancer risk by histological subtype: A prospective study in arseniasis-endemic areas in Taiwan.

Heme oxygenase (HO)-1 is upregulated by many stressful stimuli, including arsenic. A GT-repeat ((GT)n) polymorphism in the HO-1 gene promoter inversely modulates the levels of HO-1 induction. Previous HO-1 (GT)n polymorphism studies in relation to cancer risk have shown disparate results. We prospectively investigated the associations between HO-1 (GT)n polymorphism and cancer risk related to arsenic from drinking water. Totally, 1,013 participants from community-based cohorts of arseniasis-endemic areas in Taiwan were followed for 13 years. Allelic polymorphisms were classified into long (L, ≥ 27 (GT)n) and short (S, <27 (GT)n). Newly developed cases were identified through linkage with National Cancer Registry of Taiwan. Multivariate Cox proportional hazard methods were used to evaluate effects of the HO-1 polymorphism alone or combined with arsenic exposure. Results showed that participants with the S/S genotype had an increased risk of Bowen's disease (HR = 10.49; 95% CI: 2.77-39.7), invasive skin cancer (HR = 2.99; 95% CI: 1.13-7.87), and lung squamous cell carcinoma (HR = 3.39; 95% CI: 1.15-9.95) versus those with L/S or L/L genotype. The S/S genotype combined with high arsenic exposure (>300 µg/L) had a greater risk of skin cancer compared to the genotype alone. Consistent with previous findings, participants with the S-allele had a reduced risk of lung adenocarcinoma (HR = 0.21; 95% CI: 0.03-0.68) versus those with L/L genotype. There were no significant differences in risk of urothelial carcinoma among the three genotypes. Associations of HO-1 (GT)n polymorphism with cancer risk differs by histological subtype and the polymorphism should be considered a modifier in the risk assessment of arsenic exposure.

Association of Environmental Arsenic Exposure, Genetic Polymorphisms of Susceptible Genes, and Skin Cancers in Taiwan.

Deficiency in the capability of xenobiotic detoxification and arsenic methylation may be correlated with individual susceptibility to arsenic-related skin cancers. We hypothesized that glutathione S-transferase (GST M1, T1, and P1), reactive oxygen species (ROS) related metabolic genes (NQO1, EPHX1, and HO-1), and DNA repair genes (XRCC1, XPD, hOGG1, and ATM) together may play a role in arsenic-induced skin carcinogenesis. We conducted a case-control study consisting of 70 pathologically confirmed skin cancer patients and 210 age and gender matched participants with genotyping of 12 selected polymorphisms. The skin cancer risks were estimated by odds ratio (OR) and 95% confidence interval (CI) using logistic regression. EPHX1 Tyr113His, XPD C156A, and GSTT1 null genotypes were associated with skin cancer risk (OR = 2.99, 95% CI = 1.01-8.83; OR = 2.04, 95% CI = 0.99-4.27; OR = 1.74, 95% CI = 1.00-3.02, resp.). However, none of these polymorphisms showed significant association after considering arsenic exposure status. Individuals carrying three risk polymorphisms of EPHX1 Tyr113His, XPD C156A, and GSTs presented a 400% increased skin cancer risk when compared to those with less than or equal to one polymorphism. In conclusion, GSTs, EPHX1, and XPD are potential genetic factors for arsenic-induced skin cancers. The roles of these genes for arsenic-induced skin carcinogenesis need to be further evaluated.

A prospective study of gynecological cancer risk in relation to adiposity factors: cumulative incidence and association with plasma adipokine levels.

BACKGROUND: Associations of obesity and obesity-related metabolic factors (adiposity factors) with uterine corpus cancer (UCC) and ovarian cancer (OVC) risk have been described. Still, a cause-effect relationship and the underlying mediators remain unclear, particularly for low-incidence populations. We aimed to prospectively determine whether adiposity factors could predict the development of UCC and OVC in Taiwanese women. To explore the biological mediators linking adiposity factors to cancer risk, we examined the association of two adipokines, leptin and adiponectin, with the gynecological cancers. METHODS: Totally, 11,258 women, aged 30-65, were recruited into the Community-Based Cancer Screening Program (CBCSP) study during 1991-1993, and were followed for UCC and OVC cases until December 31, 2011. Cox proportional hazard models were used to estimate hazard ratios (HRs). Adiposity factors and risk covariates were assessed at recruitment. Newly-developed cancer cases were determined from data in the government's National Cancer Registry and Death Certification System. For adipokienes study, a nested case-control study was conducted within the cohort. Baseline plasma samples of 40 incident gynecological cancer cases and 240 age-menopause-matched controls were assayed for adipokines levels. FINDINGS: There were 38 and 30 incident cases of UCC and OVC, respectively, diagnosed during a median 19.9 years of follow-up. Multivariate analysis showed that alcohol intake (HR = 16.00, 95%  = 4.83-53.00), high triglyceride levels (HR = 2.58, 95% = 1.28-5.17), and years of endogenous estrogen exposure per 5-year increment (HR = 1.91, 95%  = 1.08-3.38) were associated with increased UCC risk. High body mass index (BMI ≥ 27 kg/m(2), HR = 2.90, 95%  = 1.30-6.46) was associated with increased OVC risk. Analysis further showed an independent effect of adipokines on UCC and OVC risk after adjustment of the risk covariates. CONCLUSION: We provided evidence that alcohol intake, high triglyceride levels and long endogenous estrogen exposure increase UCC risk, whereas obesity positively predicts OVC risk. Circulating adipokines may mediate the link of adiposity factors to gynecological cancer risk.

Long-term low-dose exposure of human urothelial cells to sodium arsenite activates lipocalin-2 via promoter hypomethylation.

We previously reported that the sustained exposure of human urothelial cells (HUCs) to low-dose sodium arsenite induces changes in the gene expression profile and neoplastic transformation. In this study, we used the HumanMethylation27 BeadChip to analyze genome-wide methylation profiles and 5-aza-2'-deoxycytidine to examine the involvement of promoter methylation in gene expression. Because the expression of lipocalin-2 (LCN2) was highly enhanced by promoter hypomethylation in inorganic arsenic (iAs)-HUCs cells as well as bladder cancer tissues, we further showed that mutations at the binding sequences for NF-κB and C/EBP-α significantly reduced LCN2 promoter activity. By chromatin immunoprecipitation assay, we demonstrated the significantly increased binding of RelA (p65) and NF-κB1 (p50) to the hypomethylated promoter of LCN2 in the iAs-HUCs. Furthermore, we also demonstrated that LCN2 overexpression was crucial for the neoplastic characteristics of the iAs-HUCs, such as enhanced anchorage-independent growth, resistance to serum deprivation and activation of NF-κB signaling. In addition, our results indicated that enhanced NF-κB activity in iAs-HUCs was via LCN2-mediated increase in intracellular iron and reactive oxygen species levels. Taken together, our results show that sustained low-dose arsenic exposure results in epigenetic changes and enhanced oncogenic potential via LCN2 overexpression.

Comparison of genome-wide DNA methylation in urothelial carcinomas of patients with and without arsenic exposure.

BACKGROUND: Arsenic is a well-documented carcinogen of human urothelial carcinoma (UC) with incompletely understood mechanisms. OBJECTIVES: This study aimed to compare the genome-wide DNA methylation profiles of arsenic-induced UC (AsUC) and non-arsenic-induced UC (Non-AsUC), and to assess associations between site-specific methylation levels and cumulative arsenic exposure. METHODS: Genome-wide DNA methylation profiles in 14 AsUC and 14 non-AsUC were analyzed by Illumina Infinium methylation27 BeadChip and validated by bisulfite pyrosequencing. Mean methylation levels (߯) in AsUC and non-AsUC were compared by their ratio (߯ ratio) and difference (Δ߯). Associations between site-specific methylation levels in UC and cumulative arsenic exposure were examined. RESULTS: Among 27,578 methylation sites analyzed, 231 sites had ߯ ratio >2 or <0.5 and 45 sites had Δ߯ >0.2 or <-0.2. There were 13 sites showing statistically significant (q<0.05) differences in ߯ between AsUC and non-AsUC including 12 hypermethylation sites in AsUC and only one hypermethylation site in non-AsUC. Significant associations between cumulative arsenic exposure and DNA methylation levels of 28 patients were observed in nine CpG sites of nine gens including PDGFD (Spearman rank correlation, 0.54), CTNNA2 (0.48), KCNK17 (0.52), PCDHB2 (0.57), ZNF132 (0.48), DCDC2 (0.48), KLK7 (0.48), FBXO39 (0.49), and NPY2R (0.45). These associations remained statistically significant for CpG sites in CTNNA2, KLK7, NPY2R, ZNF132 and KCNK17 in 20 non-smoking women after adjustment for tumor stage and age. CONCLUSIONS: Significant associations between cumulative arsenic exposure and methylation level of CTNNA2, KLK7, NPY2R, ZNF132 and KCNK17 were found in smoking-unrelated urothelial carcinoma. Arsenic exposure may cause urothelial carcinomas through the hypermethylation of genes involved in cell adhesion, proteolysis, transcriptional regulation, neuronal pathway, and ion transport. The findings of this study, which are limited by its small sample size and moderate dose-response relation, remain to be validated by further studies with large sample sizes.

Urinary arsenic profiles and the risks of cancer mortality: a population-based 20-year follow-up study in arseniasis-endemic areas in Taiwan.

Few studies investigated the association between chronic arsenic exposure and the mortality of cancers by estimating individual urinary arsenic methylation profiles. Therefore, we compared with the general population in Taiwan to calculate the standardized mortality ratio (SMR) in arseniasis-endemic area of Taiwan from 1996 to 2010 and evaluated the dose-response relationships between environmental arsenic exposure indices or urinary arsenic profiles and the mortality of cause-specific cancer. A cohort of 1563 residents was conducted and collected their urine sample and information regarding arsenic exposure from a questionnaire. All-cause death was identified using the National Death Registry of Taiwan. Urinary arsenic profiles were measured using high performance liquid chromatography-hydride generator-atomic absorption spectrometry. We used Cox proportional hazard models to evaluate the mortality risks. In results, 193 all-site cancer deaths, and 29, 71, 43 deaths respectively for liver, lung and bladder cancers were ascertained. The SMRs were significantly high in arseniasis-endemic areas for liver, lung, and bladder cancers. People with high urinary InAs% or low DMA% or low secondary methylation index (SMI) were the most likely to suffer bladder cancer after adjusting other risk factors. Even stopping exposure to arsenic from the artesian well water, the mortality rates of the residents were higher than general population. Finally, urinary InAs%, DMA% and SMI could be the potential biomarkers to predict the mortality risk of bladder cancer.

Epigenetic silencing of BLU through interfering apoptosis results in chemoresistance and poor prognosis of ovarian serous carcinoma patients.

Epithelial ovarian carcinoma is usually present at the advanced stage, during which the patients generally have poor prognosis. Our study aimed to evaluate the correlation of gene methylation and the clinical outcome of patients with advanced-stage, high-grade ovarian serous carcinoma. The methylation status of eight candidate genes was first evaluated by methylation-specific PCR and capillary electrophoresis to select three potential genes including DAPK, CDH1, and BLU (ZMYND10) from the exercise group of 40 patients. The methylation status of these three genes was further investigated in the validation group consisting of 136 patients. Patients with methylated BLU had significantly shorter progression-free survival (PFS; hazard ratio (HR) 1.48, 95% CI 1.01-2.56, P=0.013) and overall survival (OS; HR 1.83, 95% CI 1.07-3.11, P=0.027) in the multivariate analysis. Methylation of BLU was also an independent risk factor for 58 patients undergoing optimal debulking surgery for PFS (HR 2.37, 95% CI 1.03-5.42, P=0.043) and OS (HR 3.96, 95% CI 1.45-10.81, P=0.007) in the multivariate analysis. A possible mechanism of BLU in chemoresistance was investigated in ovarian cancer cell lines by in vitro apoptotic assays. In vitro studies have shown that BLU could upregulate the expression of BAX and enhance the effect of paclitaxel-induced apoptosis in ovarian cancer cells. Our study suggested that methylation of BLU could be a potential prognostic biomarker for advanced ovarian serous carcinoma.