Arsenic-induced Skin Research Articles

YTHDF2 phase separation promotes arsenic-induced keratinocyte transformation in a poly-m6A-dependent manner by inhibiting translational initiation of the key tumor suppressor PTEN

The phase separation of N6-methyladenosine (m6A) binding protein YTHDF2 plays a vital role in arsenic-induced skin damage, and YTHDF2 can bind to m6A-methylated mRNA of tumor suppressor PTEN. However, whether and how YTHDF2 phase separation regulates PTEN involved in arsenic-induced malignant transformation of keratinocytes remains blank. Here, we established arsenite-induced transformation models with stable expression of wild-type YTHDF2 or mutant YTHDF2 protein in vitro and in vivo. We found that the YTHDF2 protein underwent phase separation during arsenite-induced malignant transformation of keratinocytes, and YTHDF2 phase separation promoted the malignant phenotype of keratinocytes. Mechanically, YTHDF2 phase separation reduced PTEN protein levels, which in turn activated the pro-survival AKT signal. The binding of YTHDF2 to multiple m6A sites on PTEN mRNA drove YTHDF2 phase separation, inhibiting PTEN translation initiation and thus reducing PTEN protein levels. YTHDF2 phase separation recruited translation-initiation-factor kinase EIF2AK1 to phosphorylate eIF2α, thereby inhibiting translation initiation of poly-m6A-methylated PTEN mRNA. Furthermore, arsenite-induced oxidative stress triggered YTHDF2 phase separation by increasing m6A levels of PTEN mRNA. Our results demonstrated that YTHDF2 phase separation promotes arsenite-induced malignant transformation by inhibiting PTEN translation in a poly-m6A-dependent manner. This study sheds light on arsenic carcinogenicity from the novel aspect of m6A-mediated YTHDF2 phase separation.

Trivalent arsenicals induce skin toxicity through thiol depletion

Arsenic, a widespread environmental contaminant, is highly toxic to human health. Arsenic exposure is associated with the occurrence of skin lesions and diseases. This study investigated the dermal toxicity of trivalent arsenicals (AsIII and MMAIII) and its underlying mechanism using human keratinocyte cell line and ex vivo porcine skin. AsIII and MMAIII induced concentration-dependent cell apoptosis and necrosis in HaCaT cells, which was confirmed in ex vivo porcine skin. AsIII and MMAIII increased reactive oxygen species generation and GSH depletion. Interestingly, radical scavenger antioxidants such as Vitamin C failed to mitigate arsenic-induced cytotoxicity, while thiol-containing compounds effectively alleviated it, suggesting a key role of thiol depletion in the trivalent arsenical-induced dermal toxicity. DMSA showed the strongest protective effects against AsIII and MMAIII-induced cytotoxicity in HaCaT cells. Of note, DMSA restored arsenical-induced tissue damage, and reduced the apoptosis in ex vivo porcine skin, highlighting its potential use to alleviate arsenic-induced skin lesions and diseases.

Sustained high expression of NRF2 inhibits cell apoptosis in arsenite-transformed human keratinocytes

Our previous study identified that nuclear factor-erythroid-2 p45-related factor 2 (NRF2) was activated in arsenite-induced tumorigenesis. However, the underlying mechanisms of NRF2 mediating apoptosis in arsenic-induced skin carcinogenesis remain unknown. This study explored the dynamic changes in apoptosis rate and the expression of apoptosis proteins in immortalized human keratinocytes (HaCaT) malignant transformation caused by 1.0 μM NaAsO2 at passages 0, 1, 7, 14, 21, 28, and 35. The result showed that the apoptosis rate decreased. The apoptosis-related proteins cleaved-caspase-3/caspase-3 ratio decreased in the later stages (passages 21, 28, and 35). Moreover, the expression of intrinsic ER stress pathway-related CHOP, ATF4, ATF6, and the intrinsic mitochondrial pathway-related Bax protein decreased in the later stages, while Bcl-2 and Mcl-1 increased, and NRF2 protein levels also increased. The apoptosis rate increased by silencing NRF2 expression in arsenite-transformed HaCaT (T-HaCaT) cells. Meanwhile, the expression of pro-apoptotic proteins (cleaved-caspase-3/caspase-3, CHOP, Bax) and ATF4, ATF6 increased. On the contrary, antiapoptotic protein levels (Bcl-2 and Mcl-1) decreased. The ability of colony formation and migration of T-HaCaT cells decreased. In conclusion, arsenite activated NRF2 in the later stages, decreasing apoptosis characterized by inhibiting endoplasmic reticulum stress-depended and mitochondria-depended apoptosis pathway, and further promoting NaAsO2-induced HaCaT cellular malignant transformation.

Signatures of epigenetic, biological and mitotic age acceleration and telomere shortening are associated with arsenic-induced skin lesions.

Chronic arsenic exposure is a global health hazard significantly associated with the development of deleterious cutaneous changes and increased keratinocyte cancer risk. Although arsenic exposure is associated with broad-scale cellular and molecular changes, gaps exist in understanding how these changes impact the skin and facilitate malignant transformation. Recently developed epigenetic "clocks" can accurately predict chronological, biological and mitotic age, as well as telomere length, on the basis of tissue DNA methylation state. Deviations of predicted from expected age (epigenetic age dysregulation) have been associated with numerous complex diseases, increased all-cause mortality and higher cancer risk. We investigated the ability of these algorithms to detect molecular changes associated with chronic arsenic exposure in the context of associated skin lesions. To accomplish this, we utilized a multi-algorithmic approach incorporating seven "clocks" (Horvath, Skin&Blood, PhenoAge, PCPhenoAge, GrimAge, DNAmTL and epiTOC2) to analyze peripheral blood of pediatric and adult cohorts of arsenic-exposed (n = 84) and arsenic-naïve (n = 33) individuals, among whom n = 18 were affected by skin lesions. Arsenic-exposed adults with skin lesions exhibited accelerated epigenetic (Skin&Blood: + 7.0years [95% CI 3.7; 10.2], q = 6.8 × 10-4), biological (PhenoAge: + 5.8years [95% CI 0.7; 11.0], q = 7.4 × 10-2, p = 2.8 × 10-2) and mitotic age (epiTOC2: + 19.7 annual cell divisions [95% CI 1.8; 37.7], q = 7.4 × 10-2, p = 3.2 × 10-2) compared to healthy arsenic-naïve individuals; and accelerated epigenetic age (Skin&Blood: + 2.8years [95% CI 0.2; 5.3], q = 2.4 × 10-1, p = 3.4 × 10-2) compared to lesion-free arsenic-exposed individuals. Moreover, lesion-free exposed adults exhibited accelerated Skin&Blood age (+ 4.2 [95% CI 1.3; 7.1], q = 3.8 × 10-2) compared to their arsenic-naïve counterparts. Compared to the pediatric group, arsenic-exposed adults exhibited accelerated epigenetic (+ 3.1 to 4.4years (95% CI 1.2; 6.4], q = 2.4 × 10-4-3.1 × 10-3), biological (+ 7.4 to 7.8years [95% CI 3.0; 12.1] q = 1.6 × 10-3-2.8 × 10-3) and mitotic age (+ 50.0 annual cell divisions [95% CI 15.6; 84.5], q = 7.8 × 10-3), as well as shortened telomere length (- 0.23 kilobases [95% CI - 0.13; - 0.33], q = 2.4 × 10-4), across all seven algorithms. We demonstrate that lifetime arsenic exposure and presence of arsenic-associated skin lesions are associated with accelerated epigenetic, biological and mitotic age, and shortened telomere length, reflecting altered immune signaling and genomic regulation. Our findings highlight the usefulness of DNA methylation-based algorithms in identifying deleterious molecular changes associated with chronic exposure to the heavy metal, serving as potential prognosticators of arsenic-induced cutaneous malignancy.

The probable reasons of arsenic susceptibility in a chronically exposed population of West Bengal

Arsenic is potent human carcinogen which affects millions of people across the globe. Arsenic induced pre-cancerous and cancerous skin lesions are hall marks of chronic arsenic toxicity. Even then, only 15%–20% of the population manifest arsenic-induced skin lesions but the rest do not, the reason for which in not very clear. Not only that, conjunctival irritations of the eyes, peripheral neuropathy and respiratory distress are the non-dermatological health effects which are often manifested in them in addition to the cancers of skin and other internal organs. In this work we have considered 233 arsenic exposed individuals with skin lesions and 205 arsenic exposed individuals without skin lesions from the highly arsenic affected Murshidabad district of West Bengal. We have compared arsenic exposure in the two groups through drinking water. Both the study groups have similar levels of arsenic exposure, drinking same arsenic laden water. Results show that higher amounts of arsenic were retained in the nails and hair of the skin lesion group compared to the no skin lesion group. Significant higher amounts of chromosomal aberration and micronucleus formation were found in the skin lesion group, than the no skin lesion group. Incidences of conjunctival irritations of the eyes, peripheral neuropathy and respiratory distress were much higher in the former group compared to the later. We, thus found that one group was more susceptible than the other, even with similar levels of arsenic exposure. We have tried to identify and discuss the probable reasons for this observation with reference to our previous works in the exposed population from West Bengal, India.

MiR-96-5p Suppresses Progression of Arsenite-Induced Human Keratinocyte Proliferation and Malignant Transformation by Targeting Denticleless E3 Ubiquitin Protein Ligase Homolog.

Long-term exposure to arsenic has been linked to a variety of cancers, among which skin cancer is the most prevalent form. However, the mechanism underlying arsenic carcinogenesis is unclear, and there is still limited information on the role of miRNAs in arsenic-induced skin cancer. This study aims to explore the role of miR-96-5p in the arsenite-induced proliferation and malignant transformation of human HaCaT keratinocytes. The GEO database (accession numbers GSE97303, GSE97305, and GSE97306) was used to extract mRNA and miRNA expression profiles of HaCaT cells treated with or without 0.1 μmol/L sodium arsenite for 3 and 7 weeks. In this paper, according to the CCK8 assay result, HaCaT cells exposed to 0.1 μmol/L sodium arsenite for 48 h were finalized. CCK8, MTT, EdU incorporation, and colony formation assays were used to determine the viability and proliferation of HaCaT cells and transformed HaCaT (T-HaCaT) cells. The subcellular localization and relative expression levels of DTL, as well as miR-96-5p in HaCaT cells induced by arsenite, were determined via immunofluorescence, RT-qPCR, and Western blot. Dual-luciferase reporter assay was performed to identify miR-96-5p bound directly to DTL. Transfection of miR-96-5p mimics or DTL siRNA was conducted to verify the arsenite-induced viability of HaCaT cells and T-HaCaT cells. T-HaCaT cells and nude mice were used to construct arsenite-induced malignant transformation and an in vivo xenograft model to demonstrate the over-expressed effect of miR-96-5p. The results showed that DTL was the target gene of miR-96-5p. Meanwhile, we also found that 0.1 μmol/L sodium arsenite upregulated DTL by decreasing the miR-96-5p level, leading to the proliferation and malignant transformation of HaCaT cells. MiR-96-5p agomir treatment slowed the growth of transplanted HaCaT cells transformed by arsenite in a manner associated with DTL downregulation in the nude mice xenograft model. Taken together, we confirmed that miR-96-5p, as a potent regulator of DTL, suppressed arsenite-induced HaCaT cell proliferation and malignant transformation, which might provide a novel therapeutic target for the treatment of arsenic-induced skin cancer.

Assessing the health risks of coal-burning arsenic-induced skin damage: A 22-year follow-up study in Guizhou, China

Risk assessment of arsenic-induced skin damage has always received significant global attention. Theories derived from arsenic exposure in drinking water may not be applicable to the coal-burning type to arsenic-exposed area. Furthermore, very few studies have successfully determined the reference value of cumulative arsenic (CA) exposure that leads to specific skin lesions. In this study, we conducted a 22-year follow-up investigation to assess the risk of skin lesions and cancer resulting from long-term, multi-channel arsenic exposure from hazard identification, dose-response assessment, exposure assessment, and risk characterization. The results show that the arsenic exposure can significantly increase the prevalence of skin lesions. For each interquartile range increase of hair arsenic (HA) and CA, the risk of skin damage increased by 1.91 and 3.90 times, respectively. The lower confidence limit of the benchmark dose of HA of arsenic-induced various skin lesions ranged from 0.07 to 0.12 μg·g−1, and 932.57 to 1368.92 mg for CA. The chronic daily intake, lifetime average daily dose in the arsenic-exposed area after the comprehensive prevention and control measures have decreased significantly, but remained higher than the daily baseline level of 3.0 μg·kg−1·d−1. Even as recently as 2020, the hazard quotients and hazard index still exceeded 1, measuring 155.33 and 55.20, and the lifetime excess risk of skin cancer (2.80 × 10−3) remains significantly higher than the acceptable level of 10−6. Our study underscores the effectiveness of comprehensive prevention and control measures in managing high arsenic exposure in coal-burning arsenic poisoning areas. However, it is crucial to acknowledge that the risk of both non-carcinogenic and carcinogenic effects on the skin remains substantially higher than the acceptable level. We recommend setting reference limits for monitoring skin damage among individuals exposed to arsenic, with a recommended upper limit of 0.07 μg·g−1 for HA and a maximum acceptable level of 935.57 mg for CA.

Assessing the potential molecular mechanism of arsenite-induced skin cell senescence.

Arsenic exposure is a public health concern worldwide. Skin damage, as a typical lesion of arsenic exposure, the mechanism is still unknown. Studies have found that cellular senescence plays a key role in arsenic-induced skin damage, and the previous research found that the ERK/CEBPB signaling pathway may be an important molecular event of arsenic-induced skin cell senescence, but its specific mechanism is unknown. In this study, genetic engineering technology was used to construct stable HaCaT cell lines, and the role and mechanism of ERK/CEBPB signaling pathway in arsenic-induced HaCaT cell senescence were verified by knockdown and overexpression of ERK and CEBPB in both forward and backward. It was found that knockdown of CEBPB or ERK can downregulate the ERK/CEBPB signaling pathway and reduce arsenic-induced skin cell senescence. In contrast to knockdown, overexpression of CEBPB or ERK can upregulate the ERK/CEBPB signaling pathway and aggravate the senescence of skin cells caused by arsenic. These findings suggest that sodium arsenite can further promote SASP secretion and the expression of p53, p21 and p16 INK4a by activating the ERK/CEBPB signaling pathway, induce cell cycle arrest and trigger cellular senescence.

Assessing the double-edged of extracellular signal-regulated kinase/CCAAT-enhancer-binding protein beta signaling pathway in arsenic-induced skin damage and its potential foodborne interventions.

Arsenic exposure is a major environmental public health challenge worldwide. As typical manifestations for arsenic exposure, the pathogenesis of arsenic-induced skin lesions has not been fully elucidated, as well as the lack of effective control measures. In this study, we first determined the short-term and high-dose arsenic exposure can increase the apoptosis rates, while long-term low-dose arsenic exposure decrease the apoptosis rates. Then, the HaCaT cells with knockdown and overexpression of CCAAT-enhancer-binding protein β (CEBPB) and extracellular signal-regulated kinase (ERK) were constructed. The results demonstrate that knockdown of CEBPB and ERK can reduce NaAsO2 -induced cell apoptosis by inhibiting ERK/CEBPB signaling pathway and vice versa. Further cells were treated with Kaji-Ichigoside F1 (KF1). The results clearly show that KF1 can decrease the arsenic-induced cell apoptosis rates and the expression of ERK/CEBPB signaling pathway-related genes. These results provide evidence that ERK/CEBPB signaling pathway acts as a double-edged sword in arsenic-induced skin damage. Another interesting finding was that KF1 can alleviate arsenic-induced skin cell apoptosis by inhibiting the ERK/CEBPB signaling pathway. This study will contribute to a deeper understanding of the mechanisms of arsenic-induced skin cell apoptosis, and our findings will help to identify a potential food-borne intervention in arsenic detoxification.

Prevalence of arsenic-induced skin lesions and associated factors in Ethiopia: Community-based study

The study aimed to assess the prevalence of arsenic-induced skin lesions and associated factors among the population in the Adami Tulu Jido Kombolcha district, Ethiopia. A community-based cross-sectional study design was employed among 403 participants from June 02–20, 2022. A two-stage cluster sampling method was conducted to select study subjects. A pretested structured and semi-structured interview questionnaire and observation using a WHO flow chart were used for data collection. Data analysis was performed using SPSS version 24 statistical software for Windows. A multivariable binary logistic regression model was applied to examine the relationship between predictor variables and an outcome variable. The degrees of association between outcomes and predictor variables were assessed using ORs and 95% CIs, and P-values < 0.05 were considered significant. The prevalence of arsenic-induced skin lesions (arsenicosis) in the study area was 2.2% [95% CI: 1.0–3.7]. The most common arsenic-induced manifestation was keratosis (55.6%), followed by hyperpigmentation (33.3%) and hyperkeratosis (11.1%). Consumption of well water, smoking cigarettes, and chewing khat were significantly associated with arsenic-induced skin lesions. Therefore, the findings of this study should trigger further research on arsenic exposure and health risks.

N6-methyladenosine plays a dual role in arsenic carcinogenesis by temporal-specific control of core target AKT1.

High-profile RNA epigenetic modification N6-methyladenosine (m6A), as a double-edged sword for cancer, can either promote or inhibit arsenic-induced skin carcinogenesis. However, the core m6A-target gene determining the duality of m6A and the regulatory mechanism of m6A on the core gene are still poorly understood. Based on m6A microarray detection, integrated multi-omics analysis, and further experiments in vitro and in vivo, we explored the molecular basis for the dual role of m6A in cancer induced by environmental pollutants using models in different stages of arsenic carcinogenesis, including As-treated, As-transformed, and As-tumorigenic cell models. We found that the key proliferative signaling node AKT1 is in the center of the m6A-regulatory network in arsenic carcinogenicity. The m6A level on AKT1 mRNA (3'UTR, CDS, and 5'UTR) dynamically changed in different stages of arsenic carcinogenesis. The m6A writer METTL3-catalyzed upregulation of m6A promotes AKT1 expression by elevating m6A reader YTHDF1-mediated AKT1 mRNA stability in As-treated and As-transformed cells, while the m6A eraser FTO-catalyzed downregulation of m6A promotes AKT1 expression mainly by inhibiting m6A reader YTHDF2-mediated AKT1 mRNA degradation in As-tumorigenic cells. Furthermore, upregulation of m6A inhibits the expression of AKT1 negative regulator PHLPP2 and promotes the expression of AKT1 positive regulator PDK1. These changes in AKT1 regulators result in AKT1 activation by upregulating AKT1 phosphorylation at S473 and T308. Interestingly, the FTO-catalyzed decrease in m6A prevents AKT upregulation in As-treated cells but promotes AKT upregulation in As-tumorigenic cells. Both inhibitors targeting the m6A writer and eraser can inhibit the AKT1-mediated proliferation of As-tumorigenic cells by breaking the balance of m6A regulators. Our results demonstrated that AKT1 is the core hub determining m6A as a double-edged sword. Changed m6A dynamically upregulates the expression and activity of AKT1 in different stages of arsenic carcinogenesis. This study can advance our understanding of the dual role and precise time-specific mechanism of RNA epigenetics involved in the carcinogenesis of hazardous materials.

Association between serum periostin levels and the severity of arsenic-induced skin lesions.

Arsenic is a potent environmental toxicant and human carcinogen. Skin lesions are the most common manifestations of chronic exposure to arsenic. Advanced-stage skin lesions, particularly hyperkeratosis have been recognized as precancerous diseases. However, the underlying mechanism of arsenic-induced skin lesions remains unknown. Periostin, a matricellular protein, is implicated in the pathogenesis of many forms of skin lesions. The objective of this study was to examine whether periostin is associated with arsenic-induced skin lesions. A total of 442 individuals from low- (n = 123) and high-arsenic exposure areas (n = 319) in rural Bangladesh were evaluated for the presence of arsenic-induced skin lesions (Yes/No). Participants with skin lesions were further categorized into two groups: early-stage skin lesions (melanosis and keratosis) and advanced-stage skin lesions (hyperkeratosis). Drinking water, hair, and nail arsenic concentrations were considered as the participants' exposure levels. The higher levels of arsenic and serum periostin were significantly associated with skin lesions. Causal mediation analysis revealed the significant effect of arsenic on skin lesions through the mediator, periostin, suggesting that periostin contributes to the development of skin lesions. When skin lesion was used as a three-category outcome (none, early-stage, and advanced-stage skin lesions), higher serum periostin levels were significantly associated with both early-stage and advanced-stage skin lesions. Median (IQR) periostin levels were progressively increased with the increasing severity of skin lesions. Furthermore, there were general trends in increasing serum type 2 cytokines (IL-4, IL-5, IL-13, and eotaxin) and immunoglobulin E (IgE) levels with the progression of the disease. The median (IQR) of IL-4, IL-5, IL-13, eotaxin, and IgE levels were significantly higher in the early-and advanced-stage skin lesions compared to the group of participants without skin lesions. The results of this study suggest that periostin is implicated in the pathogenesis and progression of arsenic-induced skin lesions through the dysregulation of type 2 immune response.

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.

Investigating the synergistic role of heavy metals in Arsenic-induced skin lesions in West Bengal, India

BackgroundArsenic toxicity is one of the major health issues throughout the world. Approximately 108 countries that account for more than 230 million people worldwide are at high risk of arsenic poisoning mainly through drinking water and diet. Chronic exposure to arsenic causes several pathophysiological end-points including skin lesions, peripheral neuropathy, cancer, etc. In India, the population living in the lower Gangetic basin possesses a great risk of arsenicosis and other diseases. Scientists are trying to understand the gene-environmental interactions behind arsenic toxicity revealing the potential role of genetic variants of individuals. Few pieces of the literature showed that the population is not exposed to a mixture of metals. Hence, in this study, an attempt has been made to explore whether some other metals play a synergistic role in As-induced toxicity. MethodsFor this, an assessment of the level of heavy metals using ED-XRF in soil, vegetables from As-exposed areas along with quantification of the heavy metal concentration in human blood and hair of the As-exposed population were conducted. ResultsResults show the concentration of urinary arsenic is very high signifying the magnitude of the exposure. In addition to this, the levels of iron (Fe), copper (Cu), chromium (Cr) were found to be very high in soil and Fe, manganese (Mn), lead (Pb) in vegetables were exceeding the WHO/FAO recommended permissible limit. However, Fe and zinc (Zn) were predominantly high in whole blood and hair of the arsenic-exposed population when compared with the control population. ConclusionIt can be confirmed that the population from Murshidabad is exposed to As and other heavy metals through drinking water as well as food. Particularly for this population, Fe, Zn and rubidium (Rb) may play a synergistic role in arsenic-induced toxicity. However, further studies on the large population-based investigation are required to establish the chemistry of the metal toxicity.

Somatic loss of the Y chromosome is associated with arsenic exposure among Bangladeshi men.

Arsenic exposure increases the risk of several cancers in humans and contributes to genomic instability. Somatic loss of the Y chromosome (LoY) is a potential biomarker of genomic instability and cancer risk. Smoking is associated with LoY, but few other carcinogens have been investigated. We tested the cross-sectional association between arsenic exposure and LoY in leukocytes among genotyped Bangladeshi men (age 20-70 years) from the Health Effects of Arsenic Longitudinal Study. We extracted the median of logR-ratios from probes on the Y chromosome (mLRR-chrY) from genotyping arrays (n = 1364) and estimated the percentage of cells with LoY (% LoY) from mLRR-chrY. We evaluated the association between arsenic exposure (measured in drinking water and urine) and LoY using multivariable linear and logistic regression models. The association between LoY and incident arsenic-induced skin lesions was also examined. Ten percent of genotyped men had LoY in at least 5% of cells and % LoY increased with age. Among men randomly selected for genotyping (n = 778), higher arsenic in drinking water, arsenic consumed and urinary arsenic were associated with increased % LoY (P = 0.006, P = 0.06 and P = 0.13, respectively). LoY was associated with increased risk of incident skin lesions (P = 0.008). Arsenic exposure was associated with increased LoY, providing additional evidence that arsenic contributes to genomic instability. LoY was associated with developing skin lesions, a risk factor for cancer, suggesting that LoY may be a biomarker of susceptibility in arsenic-exposed populations. The effect of arsenic on somatic events should be further explored in cancer-prone tissue types.

Abstract 1440: Identifying inherited genetic variation that impacts individuals’ ability to metabolize arsenic and susceptibility to toxicity

Abstract Inorganic arsenic (iAs) is a class I human carcinogen, and exposure to iAs affects &amp;gt;200 million individuals worldwide. In Bangladesh, &amp;gt;57 million individuals are chronically exposed to iAs through drinking-water. There is inter-individual variation in arsenic metabolism efficiency (AME) due to inherited genetic variation, and this variability impacts individuals’ internal dose of arsenic and their susceptibility to toxicity. Identifying genetic determinants of AME to help identify individuals at higher risk for toxicity has been a focus within genetic epidemiology research. Consumed arsenic enters the blood in as iAs. Sequential reduction and methylation reactions are catalyzed by glutathione and arsenic methyltransferase (AS3MT) respectively, producing monomethylated (MMA) and dimethylated (DMA) forms of arsenic. Generation of DMA is beneficial because DMA is more easily expelled from the body in urine compared to MMA or iAs. AME is often represented by the percent of the arsenic species in urine that exists as DMA. Previous studies have identified genetic variants in the AS3MT (10q24.32) and FTCD (21q22.3) regions as showing clear association with AME. However, additional regions containing variants showing robust and replicable association with AME have not yet been identified, although studies of AME heritability suggest that additional variants are likely to exist. We used data from &amp;gt;7,000 participants from two studies of Bangladesh individuals with varying levels of exposure to arsenic through drinking water (The Health Effects of Arsenic Longitudinal Study, HEALS, and the Bangladesh Vitamin E and Selenium Trial, BEST) to identify genetic variation that impacts individuals’ ability to metabolize arsenic and their susceptibility to toxicity (i.e., arsenic-induced skin lesions). Our preliminary results suggest novel associations with AME in the 1q24.3 region (p= 5.16 x10-14) and with skin lesion risk in the 6p21.33 region (p=1.37x10-9). The identified variants in the 1q24.3 region reside in and around the FMO3 gene. FMOs are enzymes involved in xenobiotic metabolism; therefore, it is plausible that they may play a role in arsenic metabolism. The 6p21.33 signal is in the major histocompatibility complex (MHC) region, which contains numerous key immune response genes (e.g., HLA genes). These results suggest the existence of additional variants associated with AME and arsenic toxicity risk. Citation Format: Lizeth I. Tamayo, Lin Tong, Muhammad G. Kibriya, Farzana Jasmine, Habibul Ahsan, Brandon L. Pierce. Identifying inherited genetic variation that impacts individuals’ ability to metabolize arsenic and susceptibility to toxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1440.

Role of N6-methyladenosine RNA modification in the imbalanced inflammatory homeostasis of arsenic-induced skin lesions.

This study aimed to investigate the effect of N6-methyladenosine (m6 A) modification in modulating inflammatory homeostasis of arsenic (As)-induced skin lesions. Our bioinformatic analysis revealed abnormal expression of m6 A RNA methylation regulators and cytokines in the arsenic-exposed population. In human keratinocytes, arsenite increased the levels of m6 A methylation by upregulating the RNA methyltransferase like 3 (METTL3), mediating the disordered secretion of indicators that reflect inflammatory homeostasis (IL-6, IL-17, and IL-10). The indicators reflecting arsenic-induced skin lesions (Krt1 and Krt10) were also significantly elevated, which contributed to the occurrence of skin lesions. Our results also confirmed the association between METTL3 with inflammatory homeostasis and arsenic-induced skin lesions using arsenic-exposed human skin samples. In the arsenic-exposed group, the upregulation of METTL3 exacerbated the increase in cytokine levels (IL-6, IL-17, and IL-10), which was associated with the upregulation of keratins (Krt1 and Krt10). In addition, significant correlations among these factors corroborate the theoretical links. Finally, alteration of the m6 A levels via knockdown or enhancement of the METTL3 protein could antagonize or aggravate arsenite-induced imbalanced inflammatory homeostasis and human keratinocyte damage in HaCaT cells. Collectively, our study reveals some evidence that regulation of m6 A modification plays an important role in arsenic-induced skin lesions, which provide a new perspective on the mechanism of arsenite-induced imbalanced inflammatory homeostasis in the field of RNA epigenetics.

Assessing the Potential Value and Mechanism of Kaji-Ichigoside F1 on Arsenite-Induced Skin Cell Senescence.

Chronic exposure to inorganic arsenic is a major environmental public health issue worldwide affecting more than 220 million of people. Previous studies have shown the correlation between arsenic poisoning and cellular senescence; however, knowledge regarding the mechanism and effective prevention measures has not been fully studied. First, the associations among the ERK/CEBPB signaling pathway, oxidative stress, and arsenic-induced skin cell senescence were confirmed using the HaCaT cell model. In the arsenic-exposed group, the relative mRNA and protein expressions of ERK/CEBPB signaling pathway indicators (ERK1, ERK2, and CEBPB), cell cycle-related genes (p21, p16INK4a), and the secretion of SASP (IL-1α, IL-6, IL-8, TGF-β1, MMP-1, MMP-3, EGF, and VEGF) and the lipid peroxidation product (MDA) were significantly increased in cells (P < 0.05), while the activity of antioxidant enzyme (SOD, GSH-Px, and CAT) was significantly decreased (P < 0.05), and an increased number of cells accumulated in the G1 phase (P < 0.05). Further Kaji-ichigoside F1 intervention experiments showed that compared to that in the arsenic-exposed group, the expression level of the activity of antioxidant enzyme was significantly increased in the Kaji-ichigoside F1 intervention group (P < 0.05), but the indicators of ERK/CEBPB signaling pathway, cell cycle-related genes, and SASP were significantly decreased (P < 0.05), and the cell cycle arrest relieved to a certain extent (P < 0.05). Our study provides some limited evidence that the ERK/CEBPB signaling pathway is involved in low-dose arsenic-induced skin cell senescence, through regulating oxidative stress. The second major finding was that Kaji-ichigoside F1 can downregulate the ERK/CEBPB signaling pathway and regulate the balance between oxidation and antioxidation, alleviating arsenic-induced skin cell senescence. This study provides experimental evidence for further understanding of Kaji-ichigoside F1, a natural medicinal plant that may be more effective in preventing and controlling arsenic poisoning.

Protective Roles of Some Leafy and Non-leafy Vegetables against the Severity of Arsenic-induced Skin Lesions among Women Living in Rural Bangladesh: A Case Control Study

Arsenicosis is common among villagers as they drink more contaminatedwater since the arsenic-crisis in Bangladesh. Supplementation of vitamins and micronutrients in counteracting arsenic toxicity has been proved for arsenic treatment. This study was intended to assess protective and beneficial roles of some commonly eaten vegetables on the development and severity of arsenicinduced skin lesions. A case-control study among (N=122) adult rural-women (62 cases had various forms of arsenical skin-lesions e.g. melanosis/keratosis/ mixed-lesions and 60 sex-age-matched healthy-controls) was conducted in Shaharstee Upazilla of Chandpur district, Bangladesh. Socio-demographic data recorded in a pre-tested-questionnaire, ‘per-day vegetables ingestion’ of cases and controls were measured qualitative and quantitatively (24-hour recall-methods, food-frequency/week and food history-record/week). Multiple logistic regression/MLR analyses were performed to find out protective roles of some dietary leafy-vegetables/LVs and non-leafy vegetables/NLVs on arsenicosis and their influences on the degree of severity of arsenicosis also determined. Abstinence from taking some LVs/NLVs among cases than controls is associated with increased risk for arsenicosis (P&lt;0.05). Amongst all most-frequently eaten vegetables (n=17) per day Momordica diocia has the highest skin protective role on arsenicosis [Adjusted odds ratio/AOR 8.2, 95% CI (2.11-31.9), P=&lt;0.01], followed by Ipomoea acquatica (AOR:7.3), Basella alba (AOR:6.2), Solanum tuberosum (AOR:4.0), Vigna unguiculata sesquipedalis (AOR:3.2), Trichosanthes anguina (AOR:1.2) and Abelmoschus esculentus (AOR:1.2). Moreover, severe skin lesion was observed as compared to non-severe cases (mild/moderate) for less intake frequencies of vegetables. This study outlined that commonly eaten vegetables have protective and beneficial roles on arsenic-induced skin lesions. Large samples longitudinal study of this important field of therapeutic-intervention is warranted

Investigating the Synergistic Role of Heavy Metals in Arsenic-Induced Skin Lesions in West Bengal, India

Investigating the Synergistic Role of Heavy Metals in Arsenic-Induced Skin Lesions in West Bengal, India