Prostate cancer risk and exposure to pesticides in British Columbia farmers

An Updated Evaluation of Atrazine-Cancer Incidence Associations among Pesticide Applicators in the Agricultural Health Study Cohort

BACKGROUND

Atrazine is a common agricultural herbicide in the United States. Few epidemiologic studies have evaluated cancer risks. Previous analyses within the Agricultural Health Study (AHS) have found some evidence of associations with cancer at some sites.

OBJECTIVE

We updated exposure information, incident cases, and follow-up time to assess the associations between atrazine use and cancer at specific sites in the AHS.

METHODS

Information about lifetime pesticide use was reported at enrollment (1993-1997) and follow-up (1999-2005). Among 53,562 pesticide applicators in North Carolina and Iowa, we identified 8,915 incident cases through cancer registry linkages through 2014 (North Carolina)/2017 (Iowa). We used Poisson regression to evaluate the association between ever/never and intensity-weighted lifetime days of atrazine use and incident cancer risk controlling for several confounders. We also evaluated lagged exposures and age-stratified risk.

RESULTS

Approximately 71.2% of applicators reported ever using atrazine, which was associated with lung cancer [rate ratios  ( RR ) = 1.24 ; 95% confidence interval (CI): 1.04, 1.46]. Aggressive prostate cancer risk was increased in the highest quartile (RR Q 4 = 1.20 ; 95% CI: 0.95, 1.52; p -trend = 0.19 ), particularly among those < 60 years old (RR Q 4 = 3.04 ; 95% CI: 1.61, 5.75; p -trend < 0.001 ; p -interaction = 0.04 ). Among applicators < 50 years of age, ever-atrazine use was associated with non-Hodgkin lymphoma (NHL) (RR = 2.43 ; 95% CI: 1.10, 5.38; p -interaction = 0.60 ). For soft tissue sarcoma, there was an elevated risk in the highest tertile of exposure (RR T 3 : 2.54; 95% CI: 0.97, 6.62; p -trend = 0.31 ). In analyses with exposure lagged by 25 years, there was an elevated risk of pharyngeal (RR T 3 = 3.04 ; 95% CI: 1.45, 6.36; p -trend = 0.07 ) and kidney (RR Q 4 = 1.62 ; 95% CI: 1.15, 2.29; p -trend < 0.005 ) cancers.

DISCUSSION

We observed suggestive associations with some malignancies in overall, age-specific, and lagged analyses. Associations with aggressive prostate cancer and NHL were apparent among those diagnosed at younger ages and with cancers of the pharynx and kidney, and soft tissue sarcomas were observed in lagged analyses. Further work is needed to confirm these observed associations and elucidate potential underlying mechanisms. https://doi.org/10.1289/EHP13684.

Biological role of long non-coding RNA KCNQ1OT1 in cancer progression

Long non-coding RNAs (lncRNAs) are a type of RNAs that are more than 200 nucleotides without protein-coding potential. In recent years, more and more attention has been paid to the role of lncRNAs in cancer pathogenesis. LncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) is located on chromosome 11p15.5 with a total length of 91 kb and is highly expressed in various malignancies, which is closely related to tumor growth, lymph node metastasis, survival cycle and recurrence rate. In addition, KCNQ1OT1 is involved in the regulation of PI3K/AKT and Wnt/β-catenin signaling pathways. In this review, the mechanism and related progress of KCNQ1OT1 in different cancers were reviewed. It was found that KCNQ1OT1 can stabilize mRNA expression through sponging miRNA, which not only induced tumor cell proliferation, migration, invasion, drug resistance, epithelial-mesenchymal transition (EMT) and inhibited cell apoptosis in vitro, but also promoted tumor growth and metastasis in vivo. Therefore, as a new biomarker and therapeutic target, KCNQ1OT1 has broad prospects for the diagnosis and treatment of different cancers.

Effect of perinatal exposure to glyphosate and its mixture with 2,4-D and dicamba on rat dam kidney and thyroid function and offspring's health

The increasing use of the herbicide mixture of glyphosate, dicamba and 2-4-D to deal with glyphosate-resistant weeds raises concerns regarding human health and environmental risks. This study aimed to evaluate the effects of developmental exposure to glyphosate and a herbicide mixture containing glyphosate, dicamba and 2-4-D on rat dams' kidney and thyroid function and offspring's health. Pregnant Wistar rats were exposed from day-6 of gestation till weaning to regulatory relevant doses of glyphosate corresponding to the European Union (EU) acceptable daily intake (ADI; 0.5 mg/kg bw/day), and the no-observed-adverse-effect level (NOAEL; 50 mg/kg bw/day), and to a mixture of glyphosate, dicamba and 2,4-D all at the EU ADI (0.5, 0.002 and 0.3 mg/kg bw/day) respectively. After weaning the dams were sacrificed and blood and organs were collected. The pups' health was assessed by measuring viability, gestational and anogenital indices. Perinatal exposure to GLY alone and the herbicide mixture resulted in anti-androgenic effects in male offspring. In dams, exposure to glyphosate resulted in kidney glomerular and tubular dysfunction as well as increased thyroid hormone levels in a dose-dependent manner. Furthermore, exposure to the herbicide mixture resulted in effects similar to those observed with glyphosate at the NOAEL, suggesting at least an additive effect of the herbicide mixture at doses individually considered safe for humans.

Genetic variants of antioxidant and xenobiotic metabolizing enzymes and their association with prostate cancer: A meta-analysis and functional in silico analysis

The development and progression of prostate cancer (PCa) depends on complex interactions between genetic, environmental and dietary factors that modulate the carcinogenesis process. Interactions between chemical exposures and genetic polymorphisms in genes encoding xenobiotic metabolizing enzymes (XME), antioxidant enzymes and DNA repair enzymes have been reported as the main drivers of cancer. Thus, a better understanding of the causal risk factors for PCa will provide avenues to identify men at increased risk and will contribute to develop effective detection and prevention methods. We performed a meta-analysis on 17,518 cases and 42,507 controls obtained from 42 studies to determine whether seven SNPs and one CNV pertaining to oxidative stress, xenobiotic detoxification and DNA repair enzymes are associated with the risk of PCa (GPX1 (rs1050450), XRCC1 (rs25487), PON1 (rs662), SOD2 (rs4880), CAT (rs1001179), GSTP1 (rs1695) and CNV GSTM1). A significant increased risk of PCa was found for SOD2 (rs4880) ORGG+GA vs. AA 1.08; 95%CI 1.01-1.15, CAT (rs1001179) ORTT vs. TC+CC 1.39; 95%CI 1.17-1.66, PON1 (rs662) ORCT vs. CC+TT 1.17; 95%CI 1.01-1.35, GSTP1 (rs1695) ORGG vs. GA+AA 1.20; 95%CI 1.05-1.38 and GSTM1 (dual null vs. functional genotype) ORN vs. NN1+NN2 1.34; 95%CI 1.10-1.64. The meta-analysis showed that the CNV GSTM1, and the SNPs GSTP1 (rs1695) and CAT (rs1001179) are strongly associated with a greater risk of PCa and, to a lesser extent, the genetic variants SOD2 (rs4880) and PON1 (rs662). Although several antioxidant enzymes and XME play an important role in the PCa development, other risk factors such as chemical exposures should also be considered to gain insight on PCa risk. The functional in silico analysis showed that the genetic variants studied had no clinical implication regarding malignancy, except for GPX1 (rs1050450) SNP.

Exposure to pesticide residues in honey and its potential cancer risk assessment

Honey is the most recognized natural food by-product derived from flower nectar and the upper aero-digestive tract of the honeybees. Significance of honey for its medicinal importance are well-documented in the world's oldest medical literatures. However, the current urbanization, environmental contaminations and changes in agricultural, as well as apiculture practices has led to various types of contaminations in honey. Among all, pesticide contamination has become one of the major issues worldwide. This review focuses on the recent updates concerning pesticides occurrence in honey, as well as how the repeated use and long-term exposure to honey contaminated with pesticide residues could affect the human physiological functions, possibly leading to the development of various cancers. Our findings suggests that uncontrolled use of pesticides in farming and apiculture practices leads to the occurrence of pesticides residues in honey. Therefore, regular consumption of such honey will pose a serious threat to human health, since most of the pesticides has been reported as potential carcinogens. This review will draw the attention of honey consumers, scientific communities, apiculture farmers, as well as governing bodies to strictly monitor the pesticide usage in floriculture, agriculture as well as other related practices.

Impacts of Agricultural Pesticide Contamination: An Integrated Risk Assessment of Rural Communities of Eswatini

Marked reductions in mean annual rainfall associated with climate change in Eswatini in Southern Africa have encouraged the recycling of irrigation water and the increased use of pesticides in agricultural production, raising concerns about potential ecological and health risks due to long-term exposure to pesticide residues in soil and irrigation water. This probabilistic integrated risk assessment used liquid chromatography with tandem mass spectrometry to analyze the concentrations of four commonly used agricultural pesticides (ametryn, atrazine, pendimethalin, and 2,4-dichlorophenoxyacetic acid (2,4-D)) in irrigation water and topsoil samples from farmlands in Eswatini to assess potential ecological and health risks due to exposure. The concentrations of these pesticides ranged from undetectable to 0.104 µg/L in irrigation water and from undetectable to 2.70 µg/g in soil. The probabilistic multi-pathway and multi-route risk assessments conducted revealed hazard indices exceeding 1.0 for all age groups for ametryn and atrazine, suggesting that the daily consumption of recycled irrigation water and produce from the fields in this area may pose considerable health risks. The indices pertaining to ecological risks had values less than 0.1. Adaptation measures are recommended to efficiently manage pesticide use in agriculture, and further research will ensure that agriculture can adapt to climate change and that the general public and ecosystem are protected.

Methylated dialkylphosphate metabolites of the organophosphate pesticide malathion modify actin cytoskeleton arrangement and cell migration via activation of Rho GTPases Rac1 and Cdc42

The non-cholinergic molecular targets of organophosphate (OP) compounds have recently been investigated to explain their role in the generation of non-neurological diseases, such as immunotoxicity and cancer. Here, we evaluated the effects of malathion and its dialkylphosphate (DAP) metabolites on the cytoskeleton components and organization of RAW264.7 murine macrophages as non-cholinergic targets of OP and DAPs toxicity. All OP compounds affected actin and tubulin polymerization. Malathion, dimethyldithiophosphate (DMDTP) dimethylthiophosphate (DMTP), and dimethylphosphate (DMP) induced elongated morphologies and the formation of pseudopods rich in microtubule structures, and increased filopodia formation and general actin disorganization in RAW264.7 cells and slightly reduced stress fibers in the human fibroblasts GM03440, without significantly disrupting the tubulin or vimentin cytoskeleton. Exposure to DMTP and DMP increased cell migration in the wound healing assay but did not affect phagocytosis, indicating a very specific modification in the organization of the cytoskeleton. The induction of actin cytoskeleton rearrangement and cell migration suggested the activation of cytoskeletal regulators such as small GTPases. We found that DMP slightly reduced Ras homolog family member A activity but increased the activities of Ras-related C3 botulinum toxin substrate 1 (Rac1) and cell division control protein 42 (Cdc42) from 5 min to 2 h of exposure. Chemical inhibition of Rac1 with NSC23766 reduced cell polarization and treatment with DMP enhanced cell migration, but Cdc42 inhibition by ML-141 completely inhibited the effects of DMP. These results suggest that methylated OP compounds, especially DMP, can modify macrophage cytoskeleton function and configuration via activation of Cdc42, which may represent a potential non-cholinergic molecular target for OP compounds.

Determinants of Pesticide Exposure in Occupational Studies: A Meta-Analysis

Few epidemiological studies use exposure determinants specifically tailored to assess pesticide or plant protection product (PPP) exposures when assessing presumed association between occupational exposure and health outcomes among agricultural workers. This lack of exposure specificity could lead to results that fail to detect an association. It could be related to the lack of consensus on exposure assessment methods and the choice of exposure determinants. We conducted a meta-analysis following the PRISMA checklist to identify PPP exposure determinants used in occupational studies and identified exposure determinants that best characterized agricultural exposures to PPPs. Out of 1436 studies identified, 71 were included. The exposure determinants identified were active ingredients, chemical classes, types of PPP, crops, tasks, frequencies, duration, lifetime exposure days, and intensity-weighted exposure days. Only six over 17 associations between exposure determinants and health outcomes were found with moderate quality of evidence. Overall, epidemiological studies had difficulty defining relevant determinants to characterize PPP exposures for agricultural workers. We recommend that a standardized list of determinants for PPP exposures in occupational exposure studies should include information on formulations, intensity, duration, and frequency of PPP exposure. Harmonized data collection on exposure and health outcomes are required as well as standard units for each exposure determinant.

Pesticides and Bladder Cancer: Mechanisms Leading to Anti-Cancer Drug Chemoresistance and New Chemosensitization Strategies

Multiple risk factors have been associated with bladder cancer. This review focuses on pesticide exposure, as it is not currently known whether agricultural products have a direct or indirect effect on bladder cancer, despite recent reports demonstrating a strong correlation. While it is known that pesticide exposure is associated with an increased risk of bladder cancer in humans and dogs, the mechanism(s) by which specific pesticides cause bladder cancer initiation or progression is unknown. In this narrative review, we discuss what is currently known about pesticide exposure and the link to bladder cancer. This review highlights multiple pathways modulated by pesticide exposure with direct links to bladder cancer oncogenesis/metastasis (MMP-2, TGF-β, STAT3) and chemoresistance (drug efflux, DNA repair, and apoptosis resistance) and potential therapeutic tactics to counter these pesticide-induced affects.

Methylated and ethylated dialkylphosphate metabolites of organophosphate pesticides: DNA damage in bone marrow cells of Balb/c mice

Dialkylphosphates (DAPs), metabolites of organophosphate (OP) pesticides, are widely distributed in the environment and are often used as biomarkers of OP exposure. Recent reports indicate that DAPs may be genotoxic, both in vitro and in vivo. We have examined the genotoxicity of the methylated DAPs dimethyldithiophosphate (DMDTP) and dimethylphosphate (DMTP) and the ethylated DAPs diethyldithiophosphate (DEDTP) and diethylphosphate (DETP), in comparison with their parental compounds, malathion and terbufos, respectively, in bone marrow polychromatic erythrocytes (PCE) of male and female Balb/c mice. We also compared DNA damage (comet assay) induced by DMDTP and dimethyl phosphate (DMP) in human cell lines. Both DMDTP and DMP caused DNA damage in peripheral blood mononuclear cells, HeLa cells, and the hepatic cell lines HepG2 and WRL-68. In the in vivo micronucleus assay, methylated and ethylated DAPs increased micronucleated PCE cells in both male and female mice. Female mice were more susceptible to DNA damage. In comparison to their parental compounds, methylated DAPs, particularly DMTP, were more genotoxic than malathion; DEDTP, DETP, and terbufos were similar in potency. These results suggest that DAPs may contribute to DNA damage associated with OP pesticide exposure.

Removal of triazole and pyrethroid pesticides from wheat grain by water treatment and ultrasound-supported processes

A simple way to reduce pesticides in cereal grains is to use washing methods. The challenge of this study was to evaluate the effectiveness of reduction of 3 triazole fungicides (difenoconazole, tebuconazole, tetraconazole) and 3 pyrethroid insecticides (beta-cyfluthrin, cypermethrin, deltamethrin) commonly used in wheat protection. Four different pre-washing methods (hot and cold water washing, twice water, and ultrasound-supported washing) were evaluated. The processing factor (PF) was calculated based on the concentration of pesticides determined by LC-MS/MS in the samples of cereal grains before and after the washing process. PFs were within the range 0.01-0.97. Time, teperature and ultrasound were factors influencing the efficiency of water treatment. The study showed that ultrasound-supported washing eliminated pesticide residues to a greater extent than ordinary washing. This process significantly affected or completely reduced concentrations of triazoles in wheat grains. The highest reduction of residues (99%) was received for tebuconazole and ultrasound washing with heating temperature of 60 °C for a total of 10 min. In all washing processes, pyrethroids were removed with lower efficiency than triazoles. The lowest residue reduction was obtained for cypermethrin and washing under cold water for 5 min (3%; PF = 0.97). Beta-Cyfluthrin showed only a 6-27% reduction regardless of the process (PF: 0.73-0.95). Using static analysis, the relationship between the properties of pesticides and the reduction of their concentration in cereals was clarified and showed a strong correlation.

Consumption of fruits and vegetables contaminated with pesticide residues in Brazil: A systematic review with health risk assessment

Brazil is the third largest exporter of fruits and vegetables in the world and, consequently, uses large amounts of pesticides. Food contamination with pesticide residues (PRs) is a serious concern, especially in developing countries. Several research reports revealed that some Brazilian farmers spray pesticides on fruits and vegetables in large quantities, generating PRs after harvest. Thus, ingestion of food contaminated with PRs can cause adverse health effects. Based on information obtained through a systematic review of essential information from 33 articles, we studied the assessment of potential health risks associated with fruit and vegetable consumption in children and adults from Brazilian states. This study identified 111 PRs belonging to different chemical groups, mainly organophosphates and organochlorines, in 26 fruit and vegetable samples consumed and exported by Brazil. Sixteen of these PRs were above the Maximum Residue Limit (MRL) established by local and international legislation. We did not identify severe acute and chronic dietary risks, but the highest risk values were observed in São Paulo and Santa Catarina, associated with the consumption of tomatoes and sweet peppers due to the high concentrations of organophosphates. A high long-term health risk is associated with the consumption of oranges in São Paulo and grapes in Bahia due to chlorothalonil and procymidone. We also identified that 26 PRs are considered carcinogenic by the United States Environmental Protection Agency (US EPA), and the carcinogenic risk analysis revealed no severe risk in any Brazilian state investigated due to the cumulative hazard index (HI) < 1. However, the highest HI values were in São Paulo due to acephate and carbaryl in sweet pepper and in Bahia due to dichlorvos. This information can help regulatory authorities define new guidelines for pesticide residue limits in fruits and vegetables commonly consumed and exported from Brazil and monitor the quality of commercial formulations.

The effects of endosulfan on cell migration and invasion in prostate cancer cells via the KCNQ1OT1/miR-137-3p/PTP4A3 axis

Endosulfan belongs to persistent organic pollutants (POPs), closely related to an increased risk of prostate cancer (PCa). The existing evidence shows that lncRNAs compete with miRNAs for binding sites and contribute to the onset and progression of human malignancies. In this study we investigate how endosulfan promotes cell migration and invasion in DU145 and PC3 prostate cancer cells through epigenetic mechanism of lncRNA-miRNA regulation. Based on our past research we focused on PTP4A3 and constructed wild-type (WT) and mutant PTP4A3 plasmids for further analysis. Our results revealed that transfection of PTP4A3-WT can lead to changes in the expression of epithelial-mesenchymal transition (EMT) biomarkers and critical proteins in the TGF-β signaling pathway, and promote cell migration and invasion in PCa cells. Bioinformatics analysis shows that there were complementary sequences in PTP4A3 3'-UTR and KCNQ1OT1 3'-UTR to the seed sequence of hsa-miR-137-3p, and dual luciferase reporter assay indicates the potential binding capacity of miR-137-3p to 3'-UTR of PTP4A3 and KCNQ1OT1. We found that miR-137-3p mimic inhibited cell migration and invasion, as well as repressed alterations of EMT biomarkers and critical proteins in the TGF-β signaling pathway. Rescue experiment results revealed that co-transfection of miR-137-3p mimic and PTP4A3-WT plasmid reversed these changes following transfection with miR-137-3p mimic alone. We found that KCNQ1OT1 was predominantly distributed in the cytoplasm from a subcellular fractionation assay. Functionally, silencing of KCNQ1OT1 repressed cell migration and invasion, and caused alterations of EMT biomarkers and critical proteins in the TGF-β signaling pathway, which were all restored by co-transfection with anti-miR-137-3p or PTP4A3-WT plasmid. Furthermore, overexpression of miR-137-3p or silencing of KCNQ1OT1 dramatically rescued the effects of endosulfan on promoting cell migration and invasion. These findings suggest that endosulfan can indeed promote cell migration and invasion via the KCNQ1OT1/miR-137-3p/PTP4A3 axis in PCa cells.

Hospital-based prostate cancer screening in vietnamese men with lower urinary tract symptoms: a classification and regression tree model

BACKGROUND

Prostate cancer (PCa) is a common disease in men over 65 years of age, and should be detected early, while reducing unnecessary biopsies. This study aims to construct a classification and regression tree (CART) model (i.e., risk stratification algorithm) using multivariable approach to select Vietnamese men with lower urinary tract symptoms (LUTS) for PCa biopsy.

METHODS

We conducted a case-control study on 260 men aged ≥ 50 years who visited MEDIC Medical Center, Vietnam in 2017-2018 with self-reported LUTS. The case group included patients with a positive biopsy and the control group included patients with a negative biopsy diagnosis of PCa. Bayesian Model Averaging (BMA) was used for selecting the most parsimonious prediction model. Then the CART with 5-fold cross-validation was constructed for selecting men who can benefit from PCa biopsy in steps by steps and intuitive way.

RESULTS

BMA suggested five potential prediction models, in which the most parsimonious model including PSA, I-PSS, and age. CART advised the following cut-off points in the marked screening sequence: 18 < PSA < 33.5 ng/mL, I-PSS ≥ 19, and age ≥ 71. Patients with PSA ≥ 33.5 ng/mL have a PCa risk was 91.2%; patients with PSA < 18 ng/mL and I-PSS < 19 have a PCa risk was 7.1%. Patient with 18 ≤ PSA < 33.5ng/mL and I-PSS < 19 have a PCa risk is 70% if age ≥ 71; and is 16% if age < 71. In overall, CART reached high predictive value with AUC = 0.915. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CART at the 20% diagnosis probability threshold were 91.5%, 86.2%, 86.9%, 91.2%, and 88.9% respectively; at 80% diagnosis probability threshold were 79.2%, 92.3%, 91.2%, 81.6%, and 85.8% respectively.

CONCLUSION

CART combining PSA, I-PSS, and age has practical use in hospital-based PCa screening in Vietnamese men with lower urinary tract symptoms.

Pesticide Exposure in Relation to the Incidence of Abnormal Glucose Regulation: A Retrospective Cohort Study

Diabetes and prediabetes (called abnormal glucose regulation (AGR)) are adverse health effects associated with exposure to pesticides. However, there are few epidemiological studies on the relationship between pesticide use and the incidence of AGR. We examined the causal relationship between pesticide use and AGR incidence in a rural population using data from a Korean Farmers’ Cohort study of 1076 participants. Poisson regression with robust error variance was used to calculate the relative risks (RR) and 95% confidence intervals (CI) to estimate the relationship between pesticide exposure and AGR. The incidence of AGR in the pesticide-exposed group was 29.1%. Pesticide use increased the RR of AGR (RR 1.32, 95% CI 1.03–1.69). We observed a low-dose effect related to exposure of pesticides to AGR and a U-shaped dose–response relationship in men. Pesticide exposure is related to the incidence of AGR, and the causal relationship differs between men and women.

Halonaphthoquinones: A group of emerging disinfection byproducts of high toxicity in drinking water

Aromatic halogenated disinfection byproducts (DBPs) have received particular attention in recent years due to their high toxicity. However, most relevant researches at present focused merely on halo-monocyclic DBPs, while halo-polycyclic DBPs were scarcely explored. In this study, a new group of halo-bicyclic DBPs termed as halonaphthoquinones (HNQs) was systematically studied. By coupling with vacuum centrifugal concentrator, a SPE-UPLC-MS/MS method with high accuracy and sensitivity was developed to detect five semi-volatile HNQs in drinking water, which achieved the detection limits in the range of 0.05-0.24 ng/L. Five HNQs were identified using this method with 100% detection frequency at concentrations up to 136.7 ng/L in drinking water originated from seven water treatment plants. The cytotoxicity of the five tested HNQs in CHO-K1 cells (IC₅₀ from 3.17 to 13.18 μM) was comparable to the most toxic known carbonaceous DBP in drinking water, iodoacetic acid (IC₅₀=2.95 μM). Meanwhile, the cytotoxicity of five tested HNQs were also higher than 2,6-dichloro-1,4-benzoquinone (IC₅₀=21.73 μM) which is hundreds to thousands of times more toxic than regulated DBPs, indicating the significant toxicity risk of HNQ DBPs. To the best of our knowledge, this study presents the first analytical method for analysis of HNQ DBPs, and the first set of data on the occurrence and cytotoxicity of HNQ DBPs in drinking water. These findings are meaningful for probing deeply into the presence of varied halo-polycyclic DBPs in the aqueous environment.

Allium cepa test vs. insecticides: a scientometric and meta-analytical review

Insecticides stand out as the most dangerous pesticides, and many of them can cause cytotoxic and genotoxic effects in organisms. For this reason, a systematic review was performed focusing on the effect of insecticides on Allium cepa system by two ways: (1) a scientometric study to identify trends and gaps in the literature on the evaluation of insecticides to guide future research efforts and (2) a meta-analytical approach compiling the information to obtain an overall result about insecticide effect on A. cepa. It was found that there is an increasing production of articles in this research area. The H-index of our data set was 11, with an average of 13.72 citations per item. The leader country in this research area was India, followed by Turkey and Brazil. The best cited research area was "Environmental Sciences" and "Environmental Sciences and Ecology," followed by "Cell Biology." The most used keywords were genotoxicity, pesticides, and insecticide. The meta-analytical test showed that the number of micronuclei found in onion cells treated with insecticides is higher than that in untreated ones, and the use of pesticides reduced the mitotic index. In conclusion, it is evident the need for more studies about biotechnology, nanotechnology, and biopesticides to develop safer pesticides.

Cancer and occupational exposure to pesticides: a bibliometric study of the past 10 years

Occupational exposure to pesticides has been identified as a major trigger of the development of cancer. Pesticides can cause intoxication in the individuals who manipulate them through either inhalation, ingestion, or dermal contact. Given this, we investigated the association between the incidence of cancer and occupational exposure to pesticides through a bibliometric analysis of the studies published between 2011 and 2020, based on 62 papers selected from the Scopus database. The results indicated an exponential increase in the number of studies published over the past decade, with most of the research being conducted in the USA, France, India, and Brazil, although a further 17 nations were also involved in the research on the association between cancer and pesticides. The principal classes of pesticides investigated in relation to their role in intoxication and cancer were insecticides, herbicides, and fungicides. The types of cancer reported most frequently were multiple myeloma, bladder cancer, non-Hodgkin's lymphoma, prostate cancer, leukemia, and breast cancer. Despite the known association between pesticides and cancer, studies are still relatively scarce in comparison with the global scale of the use of these xenobiotic substances, which is related to the increasing demand for agricultural products throughout the world.

Time for Re-Evaluating the Human Carcinogenicity of Ethylenedithiocarbamate Fungicides? A Systematic Review

BACKGROUND

In January 2021, the European Union ended the license of Mancozeb, the bestselling ethylenedithiocarbamate (EBDC) fungicide, because of some properties typical of human carcinogens. This decision contrasts the IARC classification of EBDC fungicides (Group 3, not classifiable as to human carcinogenicity). A systematic review of the scientific literature was conducted to explore the current evidence.

METHODS

Human and experimental studies of cancer and exposure to EBDC fungicides (Mancozeb, Maneb, Zineb, and others) and ethylene thiourea (ETU), their major metabolite, published in English as of December 2021, were retrieved using PubMed, the list of references of the relevant reports, and grey literature.

RESULTS

The epidemiological evidence of EBDC carcinogenicity is inadequate, with two studies each suggesting an association with melanoma and brain cancer and inconsistent findings for thyroid cancer. Experimental animal studies point at thyroid cancer in rats and liver cancer in mice, while multiple organs were affected following the long-term oral administration of Mancozeb. The mechanism of thyroid carcinogenesis in rats has also been shown to occur in humans. Genotoxic effects have been reported.

CONCLUSIONS

The results of this systematic review suggest inadequate evidence for the carcinogenicity of EBDC fungicides from human studies and sufficient evidence from animal studies, with positive results on three out of ten key characteristics of carcinogens applying to humans as well. An IARC re-evaluation of the human carcinogenicity of EBDC fungicides is warranted.

Effects of Endocrine Disruptors o,p'-Dichlorodiphenyltrichloroethane, p,p'-Dichlorodiphenyltrichloroethane, and Endosulfan on the Expression of Estradiol-, Progesterone-, and Testosterone-Responsive MicroRNAs and Their Target Genes in MCF-7 Cells

Many studies have shown that dichlorodiphenyltrichloroethane (DDT) exposure raises breast cancer risk. Another insecticide with similar properties is endosulfan, which has been actively used in agriculture after DDT prohibition. Previously, we have identified some estradiol-, progesterone-, and testosterone-sensitive microRNAs (miRNAs, miRs). Because DDT and endosulfan have estrogenic, antiandrogenic, and antiprogesterone properties, we hypothesized that these miRNAs are affected by the insecticides. We quantified relative levels of miRNAs and expression levels of their target genes in breast cancer MCF-7 cells treated with p,p'-DDT, o,p'-DDT, or endosulfan. We also quantified miR-19b expression, which, as previously shown, is regulated by estrogen. Here, we observed that miR-19b expression increased in response not only to estradiol but also to testosterone and progesterone. Treatment of MCF-7 cells with p,p'-DDT or endosulfan decreased the protein levels of apoptosis regulators TP53INP1 and APAF1. In cells treated with o,p'-DDT, the TP53INP1 amount decreased after 24 h of incubation, but increased after 48 h of incubation with insecticide. OXTR expression, which is known to be associated with breast carcinogenesis, significantly diminished under the exposure of all insecticides. In cells treated with p,p'-DDT or o,p'-DDT, the observed changes were accompanied by alterations of the levels of hormone-responsive miRNAs: miR-324, miR-190a, miR-190b, miR-27a, miR-193b, and miR-19b.

The cytoskeleton as a non-cholinergic target of organophosphate compounds

Current organophosphate (OP) toxicity research now considers potential non-cholinergic mechanisms for these compounds, since the inhibition of acetylcholinesterase (AChE) cannot completely explain all the adverse biological effects of OP. Thanks to the development of new strategies for OP detection, some potential molecular targets have been identified. Among these molecules are several cytoskeletal proteins, including actin, tubulin, intermediate filament proteins, and associated proteins, such as motor proteins, microtubule-associated proteins (MAPs), and cofilin. in vitro, ex vivo, and some in vivo reports have identified alterations in the cytoskeleton following OP exposure, including cell morphology defects, cells detachments, intracellular transport disruption, aberrant mitotic spindle formation, modification of cell motility, and reduced phagocytic capability, which implicate the cytoskeleton in OP toxicity. Here, we reviewed the evidence indicating the cytoskeletal targets of OP compounds, including their strategies, the potential effects of their alterations, and their possible participation in neurotoxicity, embryonic development, cell division, and immunotoxicity related to OP compounds exposure.

Organochlorine pesticide residues in Uganda's honey as a bioindicator of environmental contamination and reproductive health implications to consumers

Honey has multifaceted nutritional and medicinal values; however, its quality is hinged on the floral origin of the nectar. Taking advantage of the large areas that they cover; honeybees are often used as bioindicators of environmental contamination. The focus of the present paper was to examine the quality of honey from within the vicinity of an abandoned pesticide store in Masindi District in western Uganda. Surficial soils (<20 cm depths) and honey samples were collected from within the vicinity of the abandoned pesticide store and analysed for organochlorine pesticide (OCP) residues using gas chromatograph coupled to an electron capture detector (GC-ECD). The mean level of ∑DDTs in all the soil samples was 503.6 µg/kg dry weight (d.w). ∑DDTs contributed 92.2% to the ∑OCPs contamination loads in the soil samples, and others (lindane, aldrin, dieldrin, and endosulfans) contributed only 7.8%. Ratio (p, p'-DDE+p, p'-DDD)/p, p'-DDT of 1.54 suggested historical DDT input in the area. In all the honey samples, the mean level of ∑DDTs was 20.9 µg/kg. ∑DDTs contributed 43.3% to ∑OCPs contamination loads in the honey samples, followed by lindane (29.8%), endosulfans (23.6%) and dieldrin (3.2%), with corresponding mean levels of 14.4, 11.4 and 1.55 µg/kg, respectively. Reproductive risk assessment was done based on the hazard quotient (HQ) and hazard index (HI) procedure. In our study, the calculated HIs for adults (102.38), and children (90.33) suggested high potential health risks to the honey consumers. Lindane, endosulfan and p, p'-DDD detected in the honey samples at levels exceeding the acute reference dose (ARfD) are known risk factors for spontaneous abortion, reduced implantation, menstrual cycle shortening, impaired semen quality, and prostate cancer in exposed individuals and experimental animal models.

Dicamba use and cancer incidence in the agricultural health study: an updated analysis

BACKGROUND

The herbicide dicamba has been commonly used agriculturally and residentially. Recent approval of genetically engineered dicamba-resistant crops is expected to lead to increased dicamba use, and there has been growing interest in potential human health effects. A prior analysis in the Agricultural Health Study (AHS) suggested associations between dicamba and colon and lung cancer. We re-evaluated dicamba use in the AHS, including an additional 12 years and 2702 exposed cancers.

METHODS

The AHS is a prospective cohort of pesticide applicators in Iowa and North Carolina. At enrollment (1993-1997) and follow-up (1999-2005), participants reported dicamba use. Exposure was characterized by cumulative intensity-weighted lifetime days, including exposure lags of up to 20 years. We estimated relative risks (RR) and 95% confidence intervals (CI) using multivariable Poisson regression for incident cancers diagnosed from enrollment through 2014/2015.

RESULTS

Among 49 922 applicators, 26 412 (52.9%) used dicamba. Compared with applicators reporting no dicamba use, those in the highest quartile of exposure had elevated risk of liver and intrahepatic bile duct cancer (nexposed = 28, RRQ4 = 1.80, CI: 1.26-2.56, Ptrend < 0.001) and chronic lymphocytic leukaemia (CLL, nexposed = 93, RRQ4 = 1.20, CI: 0.96-1.50, Ptrend = 0.01) and decreased risk of myeloid leukaemia (nexposed = 55, RRQ4 = 0.73, CI: 0.51-1.03, Ptrend = 0.01). The associations for liver cancer and myeloid leukaemia remained after lagging exposure of up to 20 years.

CONCLUSIONS

With additional follow-up and exposure information, associations with lung and colon cancer were no longer apparent. In this first evaluation of liver and intrahepatic bile duct cancer, there was an association with increasing use of dicamba that persisted across lags of up to 20 years.

Breast and prostate glands affected by environmental substances (Review)

Environmental endocrine disruptor chemicals are substances that can alter the homeostasis of the endocrine system in living organisms. They can be released from several products used in daily activities. Once in the organism, they can disrupt the endocrine function by mimicking or blocking naturally occurring hormones due to their similar chemical structure. This endocrine disruption is the most important cause of the well‑known hormone‑associate types of cancer. Additionally, it is decisive to determine the susceptibility of each organ to these compounds. Therefore, the present review aimed to summarize the effect of different environmental substances such as bisphenol A, dichlorodiphenyltrichloroethane and polychlorinated biphenyls in both the mammary and the prostate tissues. These organs were chosen due to their association with the hormonal system and their common features in carcinogenic mechanisms. Outcomes derived from the present review may provide evidence that should be considered in future debates regarding the effects of endocrine disruptors on carcinogenesis.

Micronucleus, nucleoplasmic bridge and nuclear bud frequencies in patients with laryngeal carcinoma

The aim of the study is to determine and compare micronucleus (MN), nucleoplasmic bridge (NPB) and nuclear bud (NBUD) frequencies in patients with laryngeal carcinoma and healthy controls. The study was conducted in the School of Medicine of Onsekiz Mart University. A total of 102 volunteers, 51 of whom had laryngeal carcinoma and 51 of whom were healthy control subjects, participated in this study. The Cytokinesis-Block Micronucleus Assay (CBMN) was applied to peripheral blood lymphocytes taken from patients and controls. We evaluated MN, NPBs and NBUDs frequencies in patients with laryngeal carcinoma and compared the results with those in the control group. The frequencies of MN, NPBs and NBUDs of patients with laryngeal carcinoma were found significantly higher than those in the control group (P = 0.01, P = 0.004, P = 0.01, respectively). MN, NPB and NBUD frequencies were also compared in the patients with and without pesticide exposure, and the means of all frequencies was higher in patients with pesticide exposure (P = 0.001, P = 0.02 respectively). The MN, NPBs and NBUDs frequencies of the patients with laryngeal cancer were significantly higher than those of the control group, and pesticide exposure might be a risk factor that increases genomic instability and risk of laryngeal cancer.

Chloro-s-triazines-toxicokinetic, Toxicodynamic, Human Exposure, and Regulatory Considerations

Chloro-s-triazines-atrazine, cyanazine, propazine, simazine, and terbuthylazine-are structurally similar herbicides, differing only in specific s-triazine4-and 6-N alkyl substituents. It is generally regarded that their toxicokinetics, such as, metabolic pathways, biological effects and toxicities, also share more similar features than the differences. Consequently, it is useful to compare their characteristics to potentially find useful structure-activity relationships or other similarities or differences regarding different active compounds, their metabolites, and biological effects including toxic outcomes. The ultimate goal of these exercises is to apply the summarized knowledge-as far as it is possible regarding a patchy and often inadequate database-to cross the in vitro-in vivo and animal-human borders and integrate the available data to enhance toxicological risk assessment for the benefit of humans and ecosystems.

Endosulfan triggers epithelial-mesenchymal transition via PTP4A3-mediated TGF-β signaling pathway in prostate cancer cells

Endosulfan is a persistent organochlorine pesticide that bioaccumulates in human body through the food chain and thus represents a potential risk to public health. Despite epidemiological studies, the molecular mechanisms underlying the carcinogenic effects of endosulfan in the prostate remain poorly understood. In this study, we investigated the effect of endosulfan on epithelial-mesenchymal transition (EMT) in human prostate cancer PC3 and DU145 cells. Endosulfan induced alterations of EMT biomarkers, reflecting repression of E-cadherin expression and induction of fibronectin, snail2, ZEB2, Twist1 and Vimentin. The expression of Protein-tyrosine Phosphatase 4A3 (PTP4A3) at mRNA and protein levels was upregulated by endosulfan. PTP4A3 inhibitor reversed the changes of EMT biomarkers, PTP4A3 and p-Smad2/Smad2, but did not affect the upregulation of Cleaved-Notch1 and Jagged1 in endosulfan-exposed cells. Endosulfan promoted cell migration and invasion, which were rescued by specific inhibitors for PTP4A3, TGF-β signaling and Notch signaling, respectively. These findings suggest that endosulfan promoted cell migration and invasion with the induction of EMT through PTP4A3-mediated TGF-β signaling pathway in prostate cancer cells.

Carcinogenicity and mutagenicity of malathion and its two analogues: a systematic review

Malathion has been widely used worldwide in arbovirus control programs. In 2015, it was classified by the International Agency for Research on Cancer (IARC) as a probable carcinogen to humans. This work aimed to systematize the evidence of the carcinogenic and mutagenic effects associated with the exposure of malathion and its analogs, malaoxon and isomalathion. The search was carried out in Toxline, PubMed and Scopus databases for original papers published from 1983 to 2015. In all, 73 papers were selected from a total of 273 eligible papers. The results of in vitro and in vivo studies showed mainly genetic and chromosomal damages caused by malathion. The epidemiological studies evidenced significant positive associations for thyroid, breast, and ovarian cancers in menopausal women. This evidence of the carcinogenic effect of malathion should be considered before its use in arbovirus control programs.

Concentration and distribution of pesticide residues in soil: Non-dietary human health risk assessment

Soil contamination by pesticide residues is a primary concern because of the high soil persistence of pesticides and their toxicity to humans. We investigated pesticide concentration and distribution at 3 soil depths in 147 soil samples from agricultural land and assessed potential health risks due to non-dietary human exposure to pesticides in Nepal. About sixty percent of the soil samples had pesticides (25% of the soil samples had single residue, 35% of the soil samples had mixtures of 2 or more residues) in 39 different pesticide combinations. Pesticide residues were found more frequently in topsoil. Overall, the concentration of pesticides ranged from 1.0 μg kg^-1 to 251 μg kg^-1, with a mean of 16 μg kg^-1. The concentration of the primary group, organophosphates (OPs), ranged from 1.23 μg kg^-1 to 239 μg kg^-1, with a mean of 23 μg kg^-1. Chlorpyrifos and 3,5,6-trichloro-2-pyridinol (TCP) were the predominant contaminants in soils. The ionic ratio of DDT and its degradation products suggested a continuing use of DDT in the area. Human health risk assessment of the observed pesticides in soil suggested negligible cancer risks and negligible non-cancer risks based on ingestion as the primary route of exposure. The predicted environmental concentrations (PECs) of pesticides were higher than the values found in the guidance for soil contamination used internationally. Low concentrations of residues in the soils from agricultural farms practicing integrated pest management (IPM) suggest that this farming system could reduce soil pollution in Nepal.

Genotoxicity of the organophosphate pesticide malathion and its metabolite dimethylthiophosphate in human cells in vitro

Organophosphate (OP) pesticides are biotransformed into metabolites such as dialkylphosphates (DAPs). We have evaluated the genotoxicity of malathion and its metabolite dimethylthiophosphate (DMTP) in the human hepatic cell lines HepG2 and WRL-68 and in peripheral blood mononuclear cells (PBMC). In the Cytokinesis-Block Micronucleus assay (CBMN), malathion and DMTP increased the frequencies of micronuclei (MN) and nucleoplasmic bridges (NPB). Malathion was primarily clastogenic whereas DMTP was aneuploidogenic. When HepG2 or WRL-68 cells were treated with DMTP in the presence of sulconazole, a non-specific cytochrome P450 inhibitor, MN frequency was reduced, indicating that DMTP genotoxicity requires P450-cataliyzed metabolism.

Organophosphate toxicity: updates of malathion potential toxic effects in mammals and potential treatments

Organophosphorus insecticides toxicity is still considered a major global health problem. Malathion is one of the most commonly used organophosphates nowadays, as being considered to possess relatively low toxicity compared with other organophosphates. However, widespread use may lead to excessive exposure from multiple sources. Mechanisms of MAL toxicity include inhibition of acetylcholinesterase enzyme, change of oxidants/antioxidants balance, DNA damage, and facilitation of apoptotic cell damage. Exposure to malathion has been associated with different toxicities that nearly affect every single organ in our bodies, with CNS toxicity being the most well documented. Malathion toxic effects on liver, kidney, testis, ovaries, lung, pancreas, and blood were also reported. Moreover, malathion was considered as a genotoxic and carcinogenic chemical compound. Evidence exists for adverse effects associated with prenatal and postnatal exposure in both animals and humans. This review summarizes the toxic data available about malathion in mammals and discusses new potential therapeutic modalities, with the aim to highlight the importance of increasing awareness about its potential risk and reevaluation of the allowed daily exposure level.

Inclusion of molecular descriptors in predictive models improves pesticide soil-air partitioning estimates

The soil-air exchange of pesticides is one potential fate and exposure pathways, and this process is generally thought to be governed by soil properties and environmental conditions. The experimental determination of soil-air partitioning coefficient (Ksa) is laborious and costly and typically, Ksa's are predicted from a semiempirical or a simple linear regression approach with soil and environmental variables. Here we developed a model that combined linear regression of soil, environmental and molecular parameters with the quantitative structural-property relationship (QSPR) to predict Ksa for pesticides. The values of theoretical descriptors of pesticides were calculated and the best descriptors selected using the Boruta Algorithm. Seventy-six experimental logKsa values for 17 pesticides were used in model development. Multiple linear regression (MLR) with a soil (organic carbon fraction), physicochemical (octanol-air partitioning coefficient), environmental (temperature and humidity) and molecular descriptor (Gmin, a 2D E-state molecular parameter), called as MLR-QSPR combined model exhibited better predictability (adj. r² = 0.95) of logKsa compared to MLR (adj. r² = 0.87) or QSPR (adj. r² = 0.82) itself. MLR-QSPR also showed the best performance in five-fold cross-validation (adj. r² = 0.94) and test set verification (adj. r² = 0.96). The developed model was validated and characterized by the applicability domain. Results showed that the proposed MLR-QSPR approach is highly predictive and statistically robust with >95% of predictions within ±0.5 log unit of the measured Ksa. Therefore, this approach can be used in estimating the soil-air partitioning of pesticides to better predict it's fate and transport in environments.

Pesticide use and risk of Hodgkin lymphoma: results from the North American Pooled Project (NAPP)

PURPOSE

The purpose of this study was to investigate associations between pesticide exposures and risk of Hodgkin lymphoma (HL) using data from the North American Pooled Project (NAPP).

METHODS

Three population-based studies conducted in Kansas, Nebraska, and six Canadian provinces (HL = 507, Controls = 3886) were pooled to estimate odds ratios and 95% confidence intervals for single (never/ever) and multiple (0, 1, 2-4, ≥ 5) pesticides used, duration (years) and, for select pesticides, frequency (days/year) using adjusted logistic regression models. An age-stratified analysis (≤ 40/ > 40 years) was conducted when numbers were sufficient.

RESULTS

In an analysis of 26 individual pesticides, ever use of terbufos was significantly associated with HL (OR: 2.53, 95% CI 1.04-6.17). In age-stratified analyses, associations were stronger among those ≤ 40 years of age. No significant associations were noted among those > 40 years old; however, HL cases ≤ 40 were three times more likely to report ever using dimethoate (OR: 3.76 95% CI 1.02-33.84) and almost twice as likely to have ever used malathion (OR: 1.86 95% CI 1.00-3.47). Those ≤ 40 years of age reporting use of 5 + organophosphate insecticides had triple the odds of HL (OR: 3.00 95% CI 1.28-7.03). Longer duration of use of 2,4-D, ≥ 6 vs. 0 years, was associated with elevated odds of HL (OR: 2.59 95% CI 1.34-4.97).

CONCLUSION

In the NAPP, insecticide use may increase the risk of HL, but results are based on small numbers.

The association between pesticide use and cutaneous melanoma: a systematic review and meta-analysis

BACKGROUND

The incidence of cutaneous melanoma (CM), the deadliest form of skin cancer, has gradually increased in the last decades among populations of European origin. Epidemiological studies suggested that farmers and agricultural workers are at an increased risk of CM because they were exposed to pesticides. However, little is known about the relationship between pesticides and CM.

OBJECTIVES

To investigate the association between exposure to pesticides and CM by systematically reviewing the literature. Secondary aim was to determine the categories of pesticides mainly involved in CM development.

METHODS

A systematic review of the literature was performed up to September 2018 using MEDLINE, Embase and Web of Science. Studies assessing CM risk in licensed pesticide applicators were considered. Strict criteria were established to select independent studies and risk estimates; random effect models, taking into account heterogeneity, were applied. A pooled risk estimate for CM was calculated for the use of each type of pesticide and type of exposure. Between-study and estimate heterogeneity was assessed and publication bias investigated.

RESULTS

A total of nine studies (two case-controls and seven cohorts) comprising 184 389 unique subjects were included. The summary relative risks for the categories 'herbicides - ever exposure', 'insecticides - ever exposure', 'any pesticide - ever exposure' and 'any pesticide - high exposure' resulted 1.85 [95% confidence interval (CI): 1.01, 3.36], 1.57 (95% CI: 0.58, 4.25), 1.31 (95% CI: 0.85, 2.04) and 2.17 (95% CI: 0.45, 10.36), respectively. Herbicides and insecticides had no between-study heterogeneity (I2  = 0%), while a significant heterogeneity (I2  > 50%) was detected for the high exposure to any pesticide. No indication for publication bias was found.

CONCLUSIONS

Individuals exposed to herbicides are at an increased risk of CM. Future properly designed observational studies are required to confirm this finding.

Pesticide exposure and risk of aggressive prostate cancer among private pesticide applicators

BACKGROUND

Prostate cancer (PCa) is one of the most commonly diagnosed cancers among men in developed countries; however, little is known about modifiable risk factors. Some studies have implicated organochlorine and organophosphate insecticides as risk factors (particularly the organodithioate class) and risk of clinically significant PCa subtypes. However, few studies have evaluated other pesticides. We used data from the Agricultural Health Study, a large prospective cohort of pesticide applicators in North Carolina and Iowa, to extend our previous work and evaluate 39 additional pesticides and aggressive PCa.

METHODS

We used Cox proportional hazards models, with age as the time scale, to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between ever use of individual pesticides and 883 cases of aggressive PCa (distant stage, poorly differentiated grade, Gleason score ≥ 7, or fatal prostate cancer) diagnosed between 1993 and 2015. All models adjusted for birth year, state, family history of PCa, race, and smoking status. We conducted exposure-response analyses for pesticides with reported lifetime years of use.

RESULTS

There was an increased aggressive PCa risk among ever users of the organodithioate insecticide dimethoate (n = 54 exposed cases, HR = 1.37, 95% CI = 1.04, 1.80) compared to never users. We observed an inverse association between aggressive PCa and the herbicide triclopyr (n = 35 exposed cases, HR = 0.68, 95% CI = 0.48, 0.95), with the strongest inverse association for those reporting durations of use above the median (≥ 4 years; n = 13 exposed cases, HR=0.44, 95% CI=0.26, 0.77).

CONCLUSION

Few additional pesticides were associated with prostate cancer risk after evaluation of extended data from this large cohort of private pesticide applicators.

Prostate Cancer and Asbestos: A Systematic Review and Meta-Analysis

INTRODUCTION

Asbestos-related diseases and cancers represent a major public health concern.

OBJECTIVE

To conduct a systematic review and meta-analysis to demonstrate that asbestos exposure increases the risk of prostate cancer.

METHODS

The PubMed, Cochrane Library, Embase, and ScienceDirect databases were searched using the keywords (prostate cancer OR prostatic neoplasm) AND (asbestos* OR crocidolite* OR chrysotile* OR amphibole* OR amosite*). To be included, articles needed to describe our primary outcome: Risk of prostate cancer after any asbestos exposure.

RESULTS

We included 33 studies with 15,687 cases of prostate cancer among 723,566 individuals. Asbestos exposure increased the risk of prostate cancer (effect size = 1.10, 95% confidence interval [CI] = 1.05-1.15). When we considered mode of absorption, respiratory inhalation increased the risk of prostate cancer (1.10, 95% CI = 1.05-1.14). Both environmental and occupational exposure increased the risk of prostate cancer (1.25, 95% CI = 1.01-1.48; and 1.07, 1.04-1.10, respectively). For type of fibers, the amosite group had an increased risk of prostate cancer (1.12, 95% CI = 1.05-1.19), and there were no significant results for the chrysotile/crocidolite group. The risk was higher in Europe (1.12, 95% CI = 1.05-1.19), without significant results in other continents.

DISCUSSION

Asbestos exposure seems to increase prostate cancer risk. The main mechanism of absorption was respiratory. Both environmental and occupational asbestos exposure were linked to increased risk of prostate cancer.

CONCLUSION

Patients who were exposed to asbestos should possibly be encouraged to complete more frequent prostate cancer screening.

2,4-D exposure and urinary markers of oxidative DNA damage and lipid peroxidation: a longitudinal study

Objective

2,4-Dichlorophenoxyacetic acid (2,4-D) is a herbicide that is commonly used commercially, agriculturally and residentially worldwide. There is concern about its potential for carcinogenicity based on studies in laboratory animals demonstrating the potential for induction of oxidative stress. We conducted a longitudinal biomarker study of 31 pesticide applicators in Kansas who heavily applied 2,4-D and 34 non-applicator controls.

Methods

We used multivariable generalised linear mixed-effect models to evaluate the association between urinary 2,4-D and natural log-transformed 8-iso prostaglandin F2α (8-isoprostane) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), adjusting for urinary creatinine, age, tobacco use and concomitant use of the herbicide picloram.

Results

Compared with non-applicator controls, urinary 2,4-D in the third quartile of exposure was associated with elevated 8-isoprostane (eβ=1.38, 95% CI 1.03 to 1.84). There was no association among the highest exposed and no exposure-response trend. 2,4-D exposure was not associated with 8-OHdG. Results were unchanged when restricted to participants who only applied 2,4-D (no picloram use).

Conclusions

We did not find evidence that increasing 2,4-D exposure was associated with 8-isoprostane or 8-OHdG. Future work should carefully evaluate potential confounders of this association, such as diet and physical activity, as well as additional biological markers of oxidative stress and damage.

Genetic susceptibility of CYP1A1 gene and risk of pesticide exposure in prostate cancer

BACKGROUND

The etiology of prostate cancer (PCa) is multi-factorial including environmental and genetic factors. Present study evaluates the association between level of pesticides, stress level and CYP1A1 gene polymorphism with PCa patients.

METHODS

A case control study was conducted with 102 PCa patients and age match symptomatic (n= 107) and asymptomatic benign prostatic hyperplasia (BPH, n= 70) patients. Pesticide level was characterized by Gas Chromatography. The oxidative stress and scavenging mechanisms were determined by biochemical method. Two polymorphisms of CYP1A1 gene, rs4646903 and rs1048943, were analyzed by polymerase chain reaction (PCR) followed by restriction fragment length polymorphism and allele specific PCR method.

RESULTS

Higher level of pesticide namely beta-hexachlorocyclohexane (β-HCH), Malathion, Chlorpyrifos and Fenvalerate were found in PCa group (all p value: < 0.05). Kruskal Wallis H test depicted that level of β-HCH and Malathion significantly correlated with higher grade of PCa (all p< 0.05). The PCa Patients with simultaneously low antioxidant activity and high stress level tended to suffer worst clinical outcomes. Dominant model of rs4646903 and rs1048943 suggested that substitution is associated with a higher risk of PCa (OR: 2.2, CI: 1.6-3.8, p: 0.009 and OR: 1.95, CI: 1.1-3.4, p: 0.026; respectively) and this risk was also influenced by smoking and pesticide exposure.

CONCLUSION

Environmental and genetic factors are reported to raise risk; person with high level of these pesticides especially in high risk genotype might be more susceptible to PCa.

Enzyme-based optical biosensors for organophosphate class of pesticide detection

A systematic review of enzyme based optical detection schemes for the detection and analysis of organophosphate pesticides has been presented.

Pesticide exposure and cancer: an integrative literature review

ABSTRACT We conducted an integrative literature review of published studies on pesticide and cancer exposure, focusing on farmers, rural population, pesticide applicators, and rural workers. The Medline/PubMed was used as searching database. After the retrieval, 74 articles were selected according to pre-established criteria, which design involved 39 case-controls, 32 cohorts, 2 ecological ones, and 1 cross-sectional. Among them, 64 studies showed associations between pesticides and cancer while 10 did not find any significant association. The studies found 53 different types of pesticides significantly associated with at least one type of cancer and 19 different types of cancers linked to at least one type of pesticide. Although few studies presented contradictory results, the sole fact of being a farmer or living near crops or high agricultural areas have also been used as a proxy for pesticide exposure and significantly associated with higher cancer risk. The literature well illustrates the case of prostate cancer, Non-Hodgkin lymphoma, leukemia, multiple myeloma, bladder and colon cancers. Studies are recommended to further investigate the relationship between pesticide and neoplasm of testis, breast, esophagus, kidney, thyroid, lip, head and neck, and bone.

Results of buccal micronucleus cytome assay in pesticide-exposed and non-exposed group

Since many different pesticides have been used occupationally, there have been inconsistent results regarding DNA damages among greenhouse workers. Thus, the aim of the study is to evaluate DNA damages, cell death, and chromosomal instability by using the buccal micronucleus cytome (BMcyt) assay in greenhouse workers and to compare those with a non-exposed group. The BMcyt assay was applied to the exfoliated buccal cell samples collected from 66 pesticide-exposed and 50 non-exposed individuals. We evaluated the frequency of micronucleus (MN), nuclear bud (NBUD), binucleated (BN) cells, and karyolitic (KL), pyknotic (PY), and karyorrhectic (KH) cells. The results showed that the MN, BN, PY, and KH frequencies of the pesticide-exposed group were significantly higher than those of the controls (P ˂ 0.05, P ˂ 0.05, P ˂ 0.01, and P ˂ 0.05, respectively). We observed that the MN, BN, PY, and KH frequencies in the autumn were statistically different compared with those in the control group (P = 0.037 for MN, P = 0.001 for BN, P = 0.016 for PY, and P = 0.033 for KH). The same comparison was done in the spring for the control, and there was a statistically significant difference for MN (P = 0.046) and PY (P = 0.014). We can conclude that pesticide exposure in greenhouse workers was one of the factors that altered DNA damages, cell death, and chromosomal instability in oral mucosa cells.

Hazardous effects of chemical pesticides on human health-Cancer and other associated disorders

Poisoning from pesticides is a global public health problem and accounts for nearly 300,000 deaths worldwide every year. Exposure to pesticides is inevitable; there are different modes through which humans get exposed to pesticides. The mode of exposure is an important factor as it also signifies the concentration of pesticides exposure. Pesticides are used extensively in agricultural and domestic settings. These chemicals are believed to cause many disorders in humans and wildlife. Research from past few decades has tried to answer the associated mechanism of action of pesticides in conjunction with their harmful effects. This perspective considers the past and present research in the field of pesticides and associated disorders. We have reviewed the most common diseases including cancer which are associated with pesticides. Pesticides have shown to be involved in the pathogenesis of Parkinson's and Alzheimer's diseases as well as various disorders of the respiratory and reproductive tracts. Oxidative stress caused by pesticides is an important mechanism through which many of the pesticides exert their harmful effects. Oxidative stress is known to cause DNA damage which in turn may cause malignancies and other disorders. Many pesticides have shown to modulate the gene expression at the level of non-coding RNAs, histone deacetylases, DNA methylation patterns suggesting their role in epigenetics.

Multiple Exposures and Coexposures to Occupational Hazards Among Agricultural Workers: A Systematic Review of Observational Studies

BACKGROUND

Workers may be exposed to various types of occupational hazards at the same time, potentially increasing the risk of adverse health outcomes. The aim of this review was to analyze the effects of multiple occupational exposures and coexposures to chemical, biomechanical, and physical hazards on adverse health outcomes among agricultural workers.

METHODS

Articles published in English between 1990 and 2015 were identified using five popular databases and two complementary sources. The quality of the included publications was assessed using the methodology developed by the Effective Public Health Practice Project assessment tool for quantitative studies.

RESULTS

Fifteen articles were included in the review. Multiple chemical exposures were significantly associated with an increased risk of respiratory diseases, cancer, and DNA and cytogenetic damage. Multiple physical exposures seemed to increase the risk of hearing loss, whereas coexposures to physical and biomechanical hazards were associated with an increased risk of musculoskeletal disorders among agricultural workers.

CONCLUSION

Few studies have explored the impact of multiple occupational exposures on the health of agricultural workers. A very limited number of studies have investigated the effect of coexposures among biomechanical, physical, and chemical hazards on occupational health, which indicates a need for further research in this area.

A redox-sensitive signaling pathway mediates pro-angiogenic effect of chlordecone via estrogen receptor activation

AIM

Chlordecone is able to induce pro-angiogenic effect through an estrogen receptor (ERα) pathway involving NO release and VEGF. The present study aimed to determine the molecular mechanisms by which chlordecone promotes angiogenesis in human endothelial cells.

RESULTS

High but not low concentration of chlordecone increased mitochondrial respiratory capacity and mitochondrial DNA content in endothelial cells. The ROS scavenger MnTMPyP was able to prevent the increase of both VEGF expression and capillary length induced by chlordecone. A significant increase of cytoplasmic O₂^- production was observed after 1 and 4 h incubation of chlordecone, but not after 2 h. The NADPH oxidase inhibitor apocynin or silencing p47phox prevented angiogenesis and tube formation but also the increase in production of O₂^- at 1 h. In addition, apocynin as well silencing p47phox prevented eNOS activation and the NO synthase inhibitor L-NAME inhibited mitochondrial O₂^-production. All the previous effects of chlordecone were prevented by fulvestrant.

CONCLUSION

Our results indicate that an adaptation of the mitochondrial energy metabolism occurs in the chlordecone angiogenic response. Finally, we showed that chlordecone induces endothelial cells angiogenesis by a cross-talk involving NADPH oxidase and mitochondrial O₂^-via a NO sensitive pathways through activation of ERα. These findings propose that a molecular mechanism may partly explain the epidemiological evidence implicating chlordecone as risk factor carcinogenesis.

Occupational Pesticide Exposure, Impaired DNA Repair, and Diseases

Pesticides are a mixture of chemical substances used to kill pests. Apart from their toxicity to pests, thy affect nontarget organisms. They also generate free radicals producing reactive oxygen species (ROS) which can disturb cellular pathways by inhibiting various enzymes or receptors. Pesticides also induce oxidative DNA damage, DNA adducts, and single or double strand DNA breaks. Various mechanisms of DNA repair deal with such damages and help to maintain cell integrity. Alteration in DNA repair genes modulates the individual's susceptibility towards DNA repair and various diseases. Biological monitoring provides a useful tool for the estimation of genetic risk in populations exposed to pesticides. Large numbers of evidences show that occupational exposure to pesticides in agricultural workers has been associated with an increased incidence of various diseases such as cancer, Parkinson's disease, Alzheimer's disease, reproductive disorders, and birth defects. In this review, we have discussed occupational pesticide exposure, various mechanisms of DNA damage caused by pesticides, DNA repair mechanisms, biomonitoring tools, and various diseases caused by pesticide exposure.

Deciphering the toxic effects of organochlorine pesticide, dicofol on human RBCs and lymphocytes

Organochlorine pesticides have generated growing concern owing to their diverse toxicities. In this connection, we have evaluated toxic potential of an acaricide, dicofol (DCF) and its harmful effects on human RBCs and lymphocytes. DCF caused hemolysis and rupture of human erythrocytes as confirmed by scanning electron microscopy (SEM). Significant increase in protein oxidation, lipid peroxidation, ROS production, methemoglobin formation with enhanced activities of superoxide dismutase and catalase but decreased level of reduced glutathione were observed as a result of DCF exposure to human erythrocytes. SEM showed significant DCF induced alterations in RBCs from normal discoid shape to echinocytes. Similarly, lymphocytes showed membrane damage, formation of membrane blebs and distorted cell morphology. In vitro comet assay indicated a significant DNA fragmentation in human lymphocytes upon DCF exposure. These results strongly suggest that DCF induces oxidative stress in RBCs via generation of ROS and alters the cellular architecture directly and indirectly.

Low-level arsenic exposure from drinking water is associated with prostate cancer in Iowa

Inorganic arsenic is a toxic naturally occurring element in soil and water in many regions of the US including the Midwest. Prostate cancer is the second most common type of cancer in men in Iowa, surpassed only by non-melanotic skin cancer. Epidemiology studies have evaluated arsenic exposure from drinking water and prostate cancer, but most have focused on high-level exposures outside the US. As drinking water from groundwater sources is a major source of arsenic exposure, we conducted an ecologic study to evaluate prostate cancer and arsenic in drinking water from public water sources and private wells in Iowa, where exposure levels are low, but duration of exposure can be long. Arsenic data from public water systems were obtained from the Iowa Safe Drinking Water Information System for the years 1994-2003 and for private wells from two Iowa Well Water Studies, the Iowa Community Private Well Study (ICPWS, 2002-2003) and Iowa Statewide Rural Well Water Survey Phase 2 (SWIRL2, 2006-2008) that provided data for 87 Iowa counties. Prostate cancer incidence data from 2009 to 2013 for Iowa were obtained from Surveillance, Epidemiology and End Results' SEER*Stat software. County averages of water arsenic levels varied from 1.08 to 18.6 ppb, with three counties above the current 10 ppb limit. Based on the tertiles of arsenic levels, counties were divided into three groups: low (1.08-2.06 ppb), medium (2.07-2.98 ppb), and high (2.99-18.6 ppb). Spatial Poisson regression modeling was conducted to estimate the risk ratios (RR) of prostate cancer by tertiles of arsenic level at a county level, adjusted for demographic and risk factors. The RR of prostate cancer were 1.23 (95% CI, 1.16-1.30) and 1.28 (95% CI, 1.21-1.35) in the medium and high groups, respectively, compared to the low group after adjusting for risk factors. The RR increased to 1.36 (95% CI, 1.28-1.45) in the high group when analyses were restricted to aggressive prostate cancers (Gleason score ≥ 7). This study shows a significant dose-dependent association between low-level arsenic exposure and prostate cancer, and if this result is replicated in future individual-level studies, may suggest that 10 ppb is not protective for human health.

Occupation and risk of prostate cancer in Canadian men: A case-control study across eight Canadian provinces

BACKGROUND

The etiology of prostate cancer continues to be poorly understood, including the role of occupation. Past Canadian studies have not been able to thoroughly examine prostate cancer by occupation with detailed information on individual level factors.

METHODS

Occupation, industry and prostate cancer were examined using data from the National Enhanced Cancer Surveillance System, a large population-based case-control study conducted across eight Canadian provinces from 1994 to 1997. This analysis included 1737 incident cases and 1803 controls aged 50 to 79 years. Lifetime occupational histories were used to group individuals by occupation and industry employment. Odds ratios and 95% confidence intervals were calculated and adjustments were made for known and possible risk factors.

RESULTS

By occupation, elevated risks were observed in farming and farm management (OR=1.37, 95% CI 1.02-1.84), armed forces (OR=1.33, 95% CI 1.06-1.65) and legal work (OR=2.58, 95% CI 1.05-6.35). Elevated risks were also observed in office work (OR=1.20, 95% CI 1.00-1.43) and plumbing (OR=1.77, 95% CI 1.07-2.93) and with ≥10 years duration of employment. Decreased risks were observed in senior management (OR=0.65, 95% CI 0.46-0.91), construction management (OR=0.69, 95% CI 0.50-0.94) and travel work (OR=0.37, 95% CI 0.16-0.88). Industry results were similar to occupation results, except for an elevated risk in forestry/logging (OR=1.54, 95% CI 1.06-2.25) and a decreased risk in primary metal products (OR=0.70, 95% CI 0.51-0.96).

CONCLUSION

This study presents associations between occupation, industry and prostate cancer, while accounting for individual level factors. Further research is needed on potential job-specific exposures and screening behaviours.

Use of job-exposure matrices to estimate occupational exposure to pesticides: A review

The health effects of pesticides have been extensively studied in epidemiology, mainly in agricultural populations. However, pesticide exposure assessment remains a key methodological issue for epidemiological studies. Besides self-reported information, expert assessment or metrology, job-exposure matrices still appear to be an interesting tool. We reviewed all existing matrices assessing occupational exposure to pesticides in epidemiological studies and described the exposure parameters they included. We identified two types of matrices, (i) generic ones that are generally used in case-control studies and document broad categories of pesticides in a large range of jobs, and (ii) specific matrices, developed for use in agricultural cohorts, that generally provide exposure metrics at the active ingredient level. The various applications of these matrices in epidemiological studies have proven that they are valuable tools to assess pesticide exposure. Specific matrices are particularly promising for use in agricultural cohorts. However, results obtained with matrices have rarely been compared with those obtained with other tools. In addition, the external validity of the given estimates has not been adequately discussed. Yet, matrices would help in reducing misclassification and in quantifying cumulated exposures, to improve knowledge about the chronic health effects of pesticides.

Carbaryl-induced ototoxicity in rat postnatal cochlear organotypic cultures

Carbaryl, a widely used carbamate-based insecticide, is a potent anticholinesterase known to induce delayed neurotoxicity following chronic exposure. However, its potential toxic effects on the cochlea, the sensory organ for hearing that contains cholinergic efferent neurons and acetylcholine receptors on the hair cells (HC) and spiral ganglion neurons has heretofore not been evaluated. To assess ototoxic potential of carbaryl, cochlear organotypic cultures from postnatal day 3 rats were treated with doses of carbaryl ranging from 50 to 500 μM for 48 h up to 96 h. Carbaryl damaged both the sensory HC and spiral ganglion neurons in a dose- and duration-dependent manner. HC and neuronal damage was observed at carbaryl concentrations as low as 50 μM after 96-h treatment and 100 μM after 48-h treatment. Hair cell was greatest in the high frequency basal region of the cochlea and progressively decreased towards the apex consistent with the majority of ototoxic drugs. In contrast, damage to the spiral ganglion neurons was of similar magnitude in the basal and apical regions of the cochlea. Carbaryl damage was characterized by soma shrinkage, nuclear condensation and fragmentation, and blebbing, morphological features of programmed cell death. Carbaryl upregulated the expression of executioner caspase-3 in HC and spiral ganglion neurons indicating that cellular damage occurred primarily by caspase-mediated apoptosis. These results suggest that chronic exposure to carbaryl and other carbamate anticholinesterases may be ototoxic. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 956-969, 2017.