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Fulltext Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: focus on the cancer hallmark of tumor angiogenesis

Hu Z, Brooks SA, Dormoy V, Hsu CW, Hsu HY, Lin LT, et al.

Carcinogenesis, 2015 Jun;36 Suppl 1:S184-202.
PMID: 26106137 DOI: 10.1093/carcin/bgv036

One of the important 'hallmarks' of cancer is angiogenesis, which is the process of formation of new blood vessels that are necessary for tumor expansion, invasion and metastasis. Under normal physiological conditions, angiogenesis is well balanced and controlled by endogenous proangiogenic factors and antiangiogenic factors. However, factors produced by cancer cells, cancer stem cells and other cell types in the tumor stroma can disrupt the balance so that the tumor microenvironment favors tumor angiogenesis. These factors include vascular endothelial growth factor, endothelial tissue factor and other membrane bound receptors that mediate multiple intracellular signaling pathways that contribute to tumor angiogenesis. Though environmental exposures to certain chemicals have been found to initiate and promote tumor development, the role of these exposures (particularly to low doses of multiple substances), is largely unknown in relation to tumor angiogenesis. This review summarizes the evidence of the role of environmental chemical bioactivity and exposure in tumor angiogenesis and carcinogenesis. We identify a number of ubiquitous (prototypical) chemicals with disruptive potential that may warrant further investigation given their selectivity for high-throughput screening assay targets associated with proangiogenic pathways. We also consider the cross-hallmark relationships of a number of important angiogenic pathway targets with other cancer hallmarks and we make recommendations for future research. Understanding of the role of low-dose exposure of chemicals with disruptive potential could help us refine our approach to cancer risk assessment, and may ultimately aid in preventing cancer by reducing or eliminating exposures to synergistic mixtures of chemicals with carcinogenic potential.

Matched MeSH terms: Carcinogens, Environmental/adverse effects*
A simultaneous derivatization of 3-monochloropropanediol and 1,3-dichloropropane with hexamethyldisilazane-trimethylsilyl trifluoromethanesulfonate at room temperature for efficient analysis of food sample analysis

Lee BQ, Wan Mohamed Radzi CW, Khor SM

J Chromatogr A, 2016 Feb 5;1432:101-10.
PMID: 26792449 DOI: 10.1016/j.chroma.2015.12.087

This paper reports the application of hexamethyldisilazane-trimethylsilyl trifluoromethanesulfonate (HMDS-TMSOTf) for the simultaneous silylation of 3-monochloro-1,2-propanediol (3-MCPD) and 1,3-dicholoropropanol (1,3-DCP) in solid and liquid food samples. 3-MCPD and 1,3-DCP are chloropropanols that have been established as Group 2B carcinogens in clinical testing. They can be found in heat-processed food, especially when an extended high-temperature treatment is required. However, the current AOAC detection method is time-consuming and expensive. Thus, HMDS-TMSOTf was used in this study to provide a safer, and cost-effective alternative to the HFBI method. Three important steps are involved in the quantification of 3-MCPD and 1,3-DCP: extraction, derivatization and quantification. The optimization of the derivatization process, which involved focusing on the catalyst volume, derivatization temperature, and derivatization time was performed based on the findings obtained from both the Box-Behnken modeling and a real experimental set up. With the optimized conditions, the newly developed method was used for actual food sample quantification and the results were compared with those obtained via the standard AOAC method. The developed method required less samples and reagents but it could be used to achieve lower limits of quantification (0.0043mgL(-1) for 1,3-DCP and 0.0011mgL(-1) for 3-MCPD) and detection (0.0028mgL(-1) for 1,3-DCP and 0.0008mgL(-1) for 3-MCPD). All the detected concentrations are below the maximum tolerable limit of 0.02mgL(-1). The percentage of recovery obtained from food sample analysis was between 83% and 96%. The new procedure was validated with the AOAC method and showed a comparable performance. The HMDS-TMSOTf derivatization strategy is capable of simultaneously derivatizing 1,3-DCP and 3-MCPD at room temperature, and it also serves as a rapid, sensitive, and accurate analytical method for food samples analysis.

Matched MeSH terms: Carcinogens
3-Chloropropane-1,2-diol (3-MCPD) in Soy Sauce: A Review on the Formation, Reduction, and Detection of This Potential Carcinogen

Lee BQ, Khor SM

Compr Rev Food Sci Food Saf, 2015 Jan;14(1):48-66.
PMID: 33401813 DOI: 10.1111/1541-4337.12120

Soy sauce, a dark-colored seasoning, is added to enhance the sensory properties of foods. Soy sauce can be consumed as a condiment or added during the preparation of food. There are 3 types of soy sauce: fermented, acid-hydrolyzed vegetable protein (acid- HVP), and mixtures of these. 3-Chloropropane-1,2-diol (3-MCPD) is a heat-produced contaminants formed during the preparation of soy sauce and was found to be a by-product of acid-HVP-produced soy sauce in 1978. 3-MCPD has been reported to be carcinogenic, nephrotoxic, and reproductively toxic in laboratory animal testing and has been registered as a chemosterilant for rodent control. 3-MCPD is classified as a possible carcinogenic compound, and the maximum tolerated limit in food has been established at both national and international levels. The purpose of this review is to provide an overview on the detection of 3-MCPD in soy sauce, its toxic effects, and the potential methods to reduce its concentration, especially during the production of acid-HVP soy sauce. The methods of quantification are also critically reviewed with a focus on efficiency, suitability, and challenges encountered in analysis.

Matched MeSH terms: Carcinogens
Differential-based biosensor array for fluorescence-chemometric discrimination and the quantification of subtle chloropropanols by cross-reactive serum albumin scaffolding

Wong SF, Low KH, Khor SM

Talanta, 2020 Oct 01;218:121169.
PMID: 32797922 DOI: 10.1016/j.talanta.2020.121169

Food contamination is a serious concern because of a high level of chemicals in food causes severe health issues. Safeguarding the public from the risk of adulterated foods has become a challenging mission. Chloropropanols are of importance to food safety and food security because they are common chemical food contaminants and believed to be carcinogenic to humans. In chemical sensing, chloropropanols are challenging analytes owing to the lacking diversity of functional groups and difficulty in targeting the hydroxyl group in aqueous environments. Moreover, because of their small molecular size, the compositions of chloropropanols remain challenging for achieving chromatographic determination. Herein, to simulate human smell and taste sensations, serum albumins, which are protein-based receptors, were introduced as low-selective receptors for differential sensing. Utilizing serum albumins, a fluorophore (PRODAN), and an additive (ascorbic acid), a differential-based optical biosensor array was developed to detect and differentiate chloropropanols. By integrating the sensor array with linear discriminant analysis (LDA), four chloropropanols were effectively differentiated based on their isomerism properties and the number of the hydroxyl groups, even at ultra-low concentration (5 nM). This concentration is far below the maximum tolerable level of 0.18 μM for chloropropanols. The sensing array was then employed for chloropropanols differentiation and quantification in the complex mixtures (e.g., synthetic soy and dark soy sauces). Leave-one-out cross-validation (LOOCV) analysis demonstrated 100% accurate classification for all tests. These results signify our differential sensing array as a practical and powerful tool to speedily identify, differentiate, and even quantify chloropropanols in food matrices.

Matched MeSH terms: Carcinogens
Estimation of the dietary intake and risk assessment of food carcinogens (3-MCPD and 1,3-DCP) in soy sauces by Monte Carlo simulation

Wong SF, Lee BQ, Low KH, Jenatabadi HS, Wan Mohamed Radzi CWJB, Khor SM

Food Chem, 2020 May 01;311:126033.
PMID: 31869642 DOI: 10.1016/j.foodchem.2019.126033

Quantifiable levels of 3-chloropropane-1,2-diol (3-MCPD) and 1,3-dichloro-2-propanol (1,3-DCP) were found in domestically manufactured soy-based sauces. Selected commercial foods in the Malaysian market (n = 43) were analyzed for their 3-MCPD and 1,3-DCP contents using a validated gas chromatography-mass spectrometry technique. The 3-MCPD and 1,3-DCP contents of the analyzed food samples varied from not detectable levels to 0.1223 ± 0.0419 mg kg-1 and not detectable levels to 0.025 ± 0.0041 mg kg-1, respectively. High concentrations of 3-MCPD, exceeding Malaysia's maximum tolerable limit of 0.02 mg kg-1, were found in chicken seasoning cubes (mean = 0.0898 ± 0.0378 mg kg-1). Monte Carlo simulation-based health risk assessment revealed that 3-MCPD and 1,3-DCP intakes in the 50th, 95th, and 99th percentiles were lower than 4 µg kg-1 bw day-1, the limit recommended by JECFA in 2016. Hence, it was concluded that the exposure of Malaysian citizens to chloropropanols through soy sauce consumption does not present a health risk.

Matched MeSH terms: Carcinogens/analysis*
Isolation of a quinone-rich fraction from Ardisia crispa roots and its attenuating effects on murine skin tumorigenesis

Yeong LT, Hamid RA, Yazan LS, Khaza'ai H

Asian Pac J Cancer Prev, 2013;14(4):2301-5.
PMID: 23725131

Ardisia crispa (Family: Myrsinaceae) is an evergreen, fruiting shrub that has been traditionally used as folklore medicine. Despite a scarcity of research publications, we have succeeded in showing suppressive effects on murine skin papillomagenesis. In extension, the present research was aimed at determining the effect of a quinone-rich fraction (QRF) isolated from the same root hexane extract on both initiation and promotion stages of carcinogenesis, at the selected dose of 30 mg/kg. Mice (groups I-IV) were initiated with a single dose of 7,12-dimethylbenz(α)anthracene (DMBA, 100 μg/100 μl) followed by repeated promotion of croton oil (1%) twice weekly for 20 weeks. In addition, group I (anti-initiation) received QRF 7 days before and after DMBA; group II (anti-promotion) received QRF 30 minutes before each croton oil application; group III (anti-initiation/ promotion) was treated with QRF as a combination of group I and II. A further two groups served as vehicle control (group V) and treated control (group VI). As carcinogen control, group IV showed the highest tumor volume (8.79±5.44) and tumor burden (3.60±1.17). Comparatively, group III revealed only 20% of tumor incidence, tumor burden (3.00±1.00) and tumor volume (2.40±1.12), which were significantly different from group IV. Group II also showed significant reduction of tumor volume (3.11), tumor burden (3.00) and tumor incidence (11.11%), along with prominent increase of latency period of tumor formation (week 12). Group I, nonetheless, demonstrated marked increment of tumor incidence by 40% with prompted latency period of tumor formation (week 7). No tumor formation was observed in groups V and VI. This study provided clear evidence of inhibitory effects of QRF during promotion period which was in agreement with our previous findings. The mechanism(s) underlying such effects have yet to be elucidated.

Matched MeSH terms: Carcinogens/toxicity
Fulltext The Inhibitory Effects of Heterotrigona Itama Honey Marinades on the Formation of Carcinogenic Heterocyclic Amines in Grilled Beef Satay

Shamsudin S, Selamat J, Sanny M, Jambari NN, Sukor R, Praveena SM, et al.

Molecules, 2020 Aug 26;25(17).
PMID: 32858787 DOI: 10.3390/molecules25173874

Heterocyclic amines (HCAs) are carcinogenic food toxicants formed in cooked meats, which may increase the risk of cancer development in humans. Therefore, in this study, the effect of stingless bee honey from different botanical origins on the formation of HCAs in grilled beef satay was investigated. HCAs concentration in grilled beef satay was determined by using high performance liquid chromatography (HPLC). In total, six of the most toxigenic HCAs representing aminoimidazo-azaarenes (AIAs) (MeIQx, 4,8-DiMeIQx, and PhIP) and amino carbolines (norharman, harman, and AαC) groups were identified in all the beef samples investigated. A significant reduction in HCAs was observed in grilled beef marinated in honey as compared to beef samples marinated in table sugar (control), in which the reduction of 95.14%, 88.45%, 85.65%, and 57.22% was observed in gelam, starfruit, acacia, and Apis honey marinades, respectively. According to the partial least squares regression (PLS) model, the inhibition of HCAs in grilled beef was shown to be significantly correlated to the antioxidant activity (IC50) of the honey samples. Therefore, the results of this study revealed that the addition of stingless bee honey could play an important role in reducing HCAs in grilled beef.

Matched MeSH terms: Carcinogens/analysis*
Long-term tocotrienol supplementation and glutathione-dependent enzymes during hepatocarcinogenesis in the rat

Rahmat A, Wan Ngah WZ, Gapor A, Khalid BA

Asia Pac J Clin Nutr, 1993 Sep;2(3):129-34.
PMID: 24352144

The effects of long-term administration of tocotrienol on hepatocarcinogenesis in rats induced by diethyl nitrosamine (DEN) and 2-acetylaminofluorene (AAF) were investigated by the determination of plasma and liver gamma-glutamyl transpeptidase (GGT), cytosolic glutathione reductase (GSSG-Rx), glutathione peroxidase (GSH-Px) and glutathione S-transferase (GST). Twenty-eight male Rattus norwegicus rats (120-160g) were divided according to treatments into four groups: control group, tocotrienol - supplemented diet group (30mg/kg food), DEN/AAF-treated group and DEN/AAF treated plus tocotrienol-supplemented-diet group (30mg/kg food). The rats were sacrificed after nine months. The results obtained indicated no difference in the morphology and histology of the livers of control and tocotrienol-treated rats. Greyish-white neoplastic nodules (two per liver) were found in all the DEN/ AAF treated rats (n-10) whereas only one nodule was found in one of the carcinogen treated rats receiving tocotrienol supplementation (n-6). Histological examination showed obvious cellular damage for both the DEN/AAF-treated rats and the tocotrienol-supplemented rats but were less severe in the latter. Treatment with DEN/AAF caused increases in GGT, GSH-Px, GST and GSSG-Rx activities when compared to controls. These increases were also observed when tocotrienol was supplemented with DEN/AAF but the increases were less when compared to the rats receiving DEN/AAF only.

Matched MeSH terms: Carcinogens
Effect of ovariectomy and sex hormones replacement on tumour marker enzymes under administration of chemical carcinogens in the rat

Zarida H, Wan Zurinah WN, Zanariah J, Michael LK, Khalid BA

Exp. Toxicol. Pathol., 1994 Mar;46(1):31-6.
PMID: 7916223

The effect of ovariectomy and sex hormone/s replacement in female rats was investigated by the determination of the tumour marker enzymes gamma-glutamyltranspeptidase (GGT) and alkaline phosphatase (ALP). This was compared to ovariectomized rats receiving sex hormone replacement and treated with carcinogen. Ovariectomy significantly increased the activity of plasma GGT. Plasma and microsomal ALP and microsomal GGT were unchanged. When replacements of estrogen (E), or progesterone (Prog), or combinations of both estrogen and progesterone were given to ovariectomized rats, the activity of plasma GGT was brought to the level of normal intact females. Treatment with carcinogen increased the PGGT activities in intact rats. In ovariectomized rats receiving carcinogen, the PGGT activities were significantly lower than in intact females and rats receiving both hormone replacement and carcinogen (p < 0.01). Carcinogen treatment in case of estrogen or progesterone replacement, either individually or in combination, showed GGT activities comparable to intact females receiving carcinogen. Both plasma and microsomal ALP were not affected by carcinogen administration. These results showed that ovariectomy reduced the severity of hepatocarcinogenesis while sex hormone replacement worsened the process.

Matched MeSH terms: Carcinogens/pharmacology*
Mechanical and thermal properties of palm-based polyurethane composites filled with Fe3O4, PANI and PANI/Fe3O4

Liow CH, Sahrim Ahmad, Khairiah Badri

Sains Malaysiana, 2011;40.

In-situ polymerization method was used to prepare palm-based polyurethane (PU) composites loading with 15 wt% magnetite (Fe3O4), polyaniline (PANI) and Fe3O4 coated with PANI labeled as PU15, PP and PPM, respectively. FTIR spectroscopy analysis indicated a shift in the carbonyl, C=O and NH in PP. The shift of the peak indicated that there was hydrogen bonding between the C=O (proton acceptor) of urethane with NH (proton-donator) of PANI. PPM gave the highest impact and flexural strengths at 4875 kJ/ m2 and 42 MPa, respectively but with the lowest flexural modulus (1050 MPa). Two-stage degradation behavior was observed in the TGA thermogram.

Matched MeSH terms: Carcinogens
Fulltext FGFR3 mutation increases bladder tumourigenesis by suppressing acute inflammation

Foth M, Ismail NFB, Kung JSC, Tomlinson D, Knowles MA, Eriksson P, et al.

J Pathol, 2018 Nov;246(3):331-343.
PMID: 30043421 DOI: 10.1002/path.5143

Recent studies of muscle-invasive bladder cancer show that FGFR3 mutations are generally found in a luminal papillary tumour subtype that is characterised by better survival than other molecular subtypes. To better understand the role of FGFR3 in invasive bladder cancer, we examined the process of tumour development induced by the tobacco carcinogen OH-BBN in genetically engineered models that express mutationally activated FGFR3 S249C or FGFR3 K644E in the urothelium. Both occurrence and progression of OH-BBN-driven tumours were increased in the presence of an S249C mutation compared to wild-type control mice. Interestingly, at an early tumour initiation stage, the acute inflammatory response in OH-BBN-treated bladders was suppressed in the presence of an S249C mutation. However, at later stages of tumour progression, increased inflammation was observed in S249C tumours, long after the carcinogen administration had ceased. Early-phase neutrophil depletion using an anti-Ly6G monoclonal antibody resulted in an increased neutrophil-to-lymphocyte ratio at later stages of pathogenesis, indicative of enhanced tumour pathogenesis, which supports the hypothesis that suppression of acute inflammation could play a causative role. Statistical analyses of correlation showed that while initial bladder phenotypes in morphology and inflammation were FGFR3-dependent, increased levels of inflammation were associated with tumour progression at the later stage. This study provides a novel insight into the tumour-promoting effect of FGFR3 mutations via regulation of inflammation at the pre-tumour stage in the bladder. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Matched MeSH terms: Carcinogens
Suppression of β-catenin and cyclooxygenase-2 expression and cell proliferation in azoxymethane-induced colonic cancer in rats by rice bran phytic acid (PA)

Saad N, Esa NM, Ithnin H

Asian Pac J Cancer Prev, 2013;14(5):3093-9.
PMID: 23803085

BACKGROUND: Phytic acid (PA) is a polyphosphorylated carbohydrate that can be found in high amounts in most cereals, legumes, nut oil, seeds and soy beans. It has been suggested to play a significant role in inhibition of colorectal cancer. This study was conducted to investigate expression changes of β-catenin and cyclooxygenase-2 (COX-2) and cell proliferation in the adenoma-carcinoma sequence after treatment with rice bran PA by immunocytochemistry.
MATERIALS AND METHODS: Seventy-two male Sprague-Dawley rats were divided into 6 equal groups with 12 rats in each group. For cancer induction two intraperitoneal injections of azoxymethane (AOM) were given at 15 mg/kg bodyweight over a 2-weeks period. During the post initiation phase, two different concentrations of PA, 0.2% (w/v) and 0.5% (w/v) were administered in the diet.
RESULTS: Results of β-catenin, COX-2 expressions and cell proliferation of Ki-67 showed a significant contribution in colonic cancer progression. For β-catenin and COX-2 expression, there was a significant difference between groups at p<0.05. With Ki-67, there was a statistically significant lowering the proliferating index as compared to AOM alone (p<0.05). A significant positive correlation (p=0.01) was noted between COX-2 expression and proliferation. Total β-catenin also demonstrated a significant positive linear relationship with total COX-2 (p=0.044).
CONCLUSIONS: This study indicated potential value of PA extracted from rice bran in reducing colonic cancer risk in rats.

Matched MeSH terms: Carcinogens/toxicity
Kenaf seed supercritical fluid extract reduces aberrant crypt foci formation in azoxymethane-induced rats

Ghafar SA, Yazan LS, Tahir PM, Ismail M

Exp. Toxicol. Pathol., 2012 Mar;64(3):247-51.
PMID: 20869858 DOI: 10.1016/j.etp.2010.08.016

Kenaf (Hibiscus cannabinus) a plant of the family Malvaceae, is a valuable fiber plant native to India and Africa. Kenaf seeds contain alpha-linolenic acid, phytosterol such as β-sitosterol, vitamin E and other antioxidants with chemopreventive properties. In the present study we examined the hypothesis that kenaf seed 'supercritical fluid extract' (SFE) extract could suppress the early colon carcinogenesis in vivo by virtue of its bioactive compounds. To accomplish this goal, 60 male rats were randomly assigned to 5 groups which were (1) negative control group [not induced with azoxymethane (AOM)]; (2) positive control group (induced with AOM but received no treatment); (3) group treated with 500 mg/kg kenaf seed SFE extract; (4) group treated with 1000 mg/kg kenaf seed SFE extract; (5) group treated with 1500 mg/kg kenaf seed SFE extract. At 7 weeks of age, all rats except the negative control group received 15 mg/kg of AOM injection subcutaneously once a week for 2 weeks. Rats were euthanized at 13 weeks of the experiment. Number of ACF (mean±SD) ranged from 84.4±4.43 to 179.5±12.78 in group 2, 3, 4, 5. ACF reductions compared with the untreated group were 45.3, 51.4 and 53.1% in rats fed with 500, 1000 and 1500 mg/kg body weight, respectively. There were no significant differences in weight gain among groups. Our finding indicates that kenaf seed SFE extract reduced AOM-induced ACF in Sprague-Dawley male rats.

Matched MeSH terms: Carcinogens/toxicity
Isothiocyanates and Xenobiotic Detoxification

Abdull Razis AF, Konsue N, Ioannides C

Mol Nutr Food Res, 2018 09;62(18):e1700916.
PMID: 29288567 DOI: 10.1002/mnfr.201700916

The potential of isothiocyanates to antagonize the carcinogenicity of structurally diverse chemicals has been established in animals. A feasible mechanism of action involves protecting DNA by reducing the availability of the genotoxic metabolites of chemical carcinogens by either inhibiting their generation and/or stimulating their detoxification. In vivo as well as in vitro studies conducted in rat/human primary hepatocytes and precision-cut tissue slices have revealed that isothiocyanates can impair cytochrome P450 activity, including the CYP1 family which is the most active in the bioactivation of carcinogens, by virtue of being mechanism-based inactivators. The aromatic phenethyl isothiocyanate is the most effective of those studied, whereas aliphatic isothiocyanates such as sulforaphane and erucin necessitate high doses in order to manifest such effects that may not always be achievable through the diet. In all systems studied, isothiocyanates are strong inducers of detoxification enzyme systems including quinone reductase, glutathione S-transferase, epoxide hydrolase, and UDP-glucuronosyl transferase. Indeed, in smokers phenethyl isothiocyanate intake increases the urinary excretion of inactive mercapturate metabolites of toxic chemicals present in tobacco. Glucosinolates, the precursors of isothiocyanates, have also the potential to upregulate detoxification enzyme systems, but their contribution to the cancer chemoprevention linked to cruciferous vegetable consumption remains to be evaluated.

Matched MeSH terms: Carcinogens/metabolism; Carcinogens/toxicity
Fulltext Health risk assessment and source apportionment of potentially toxic metal(loid)s in windowsill dust of a rapidly growing urban settlement, Iran

Madadi R, Mohamadi S, Rastegari M, Karbassi A, Rakib MRJ, Khandaker MU, et al.

Sci Rep, 2022 Nov 17;12(1):19736.
PMID: 36396803 DOI: 10.1038/s41598-022-21242-z

Rapid industrialization and urbanization have resulted in environmental pollution and unsustainable development of cities. The concentration of 12 potentially toxic metal(loid)s in windowsill dust samples (n = 50) were investigated from different functional areas of Qom city with the highest level of urbanization in Iran. Spatial analyses (ArcGIS 10.3) and multivariate statistics including Principal Component Analysis and Spearman correlation (using STATISTICA-V.12) were adopted to scrutinize the possible sources of pollution. The windowsill dust was very highly enriched with Sb (50 mg/kg) and Pb (1686 mg/kg). Modified degree of contamination (mCd) and the pollution load indices (PLIzone) indicate that windowsill dust in all functional areas was polluted in the order of industrial > commercial > residential > green space. Arsenic, Cd, Mo, Pb, Sb, Cu, and Zn were sourced from a mixture of traffic and industrial activities, while Mn in the dust mainly stemmed from mining activities. Non-carcinogenic health risk (HI) showed chronic exposure of Pb for children in the industrial zone (HI = 1.73). The estimations suggest the possible carcinogenic risk of As, Pb, and Cr in the dust. The findings of this study reveal poor environmental management of the city. Emergency plans should be developed to minimize the health risks of dust to residents.

Matched MeSH terms: Carcinogens/analysis
Fulltext Decolorization of Palm Oil Mill Effluent by Klebsiella Pneumonia ABZ11: Remediation Efficacy and Statistical Optimization of Treatment Conditions

Abdulsalam M, Man HC, Abidin ZZ, Yunos KF, Idris AI

Front Microbiol, 2020;11:675.
PMID: 32477278 DOI: 10.3389/fmicb.2020.00675

Colorants contained in palm oil mill effluent (POME) are recalcitrant and carcinogenic in nature. The commonly applied ponding treatment methods have been reported inefficient for remediating the concentration of the colorants before discharge. The need for sustainable and efficient treatment technique is crucial in order to preserve the environment. In this view, this study reported the first attempt to decolorize POME using a proliferate Klebsiella Pneumonia ABZ11 at varied inoculum sizes of 5-25% (v/v), initial color concentration (650-2,600 ADMI) and treatment time of 5-40 h. The treatment conditions were optimized using Response Surface Methodology. At optimal conditions of 20% (v/v) inoculum size, initial-color concentration of 2,600 ADMI, initial pH of 7 and 35 h treatment retention time, over 80.40% color removal was achieved with insignificant disparity compared with the model predicted value of 81.538%. Also, the Monod model excellently described the decolorization kinetic process with 0.9214 coefficient of correlation (R2), and the calculated maximum growth μ
max
) and half-saturation constant (K
s
) were 7.023 d-1 and 340.569 ADMI d-1, respectively. This study revealed that the Klebsiella Pneumonia ABZ11 was highly prolific and such feature may favor a synergistic biodegradation process.

Matched MeSH terms: Carcinogens
Fulltext Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead

Goodson WH, Lowe L, Carpenter DO, Gilbertson M, Manaf Ali A, Lopez de Cerain Salsamendi A, et al.

Carcinogenesis, 2015 Jun;36 Suppl 1:S254-96.
PMID: 26106142 DOI: 10.1093/carcin/bgv039

Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology.

Matched MeSH terms: Carcinogens, Environmental/adverse effects*
Fulltext An Electrochemical DNA Biosensor for Carcinogenicity of Anticancer Compounds Based on Competition between Methylene Blue and Oligonucleotides

Md Sani ND, Ariffin EY, Sheryn W, Shamsuddin MA, Heng LY, Latip J, et al.

Sensors (Basel), 2019 Nov 22;19(23).
PMID: 31766637 DOI: 10.3390/s19235111

A toxicity electrochemical DNA biosensor has been constructed for the detection of carcinogens using 24 base guanine DNA rich single stranded DNA, and methylene blue (MB) as the electroactive indicator. This amine terminated ssDNA was immobilized onto silica nanospheres and deposited on gold nanoparticle modified carbon-paste screen printed electrodes (SPEs). The modified SPE was initially exposed to a carcinogen, followed by immersion in methylene blue for an optimized duration. The biosensor response was measured using differential pulse voltammetry. The performance of the biosensor was identified on several anti-cancer compounds. The toxicity DNA biosensor demonstrated a linear response range to the cadmium chloride from 0.0005 ppm to 0.01 ppm (R2 = 0.928) with a limit of detection at 0.0004 ppm. The biosensor also exhibited its versatility to screen the carcinogenicity of potential anti-cancer compounds.

Matched MeSH terms: Carcinogens/chemistry*
Fulltext Health risk assessment among adult and children on potential air pollutants released from the petrochemical plant in Malaysia: the result of air modelling

Mohd Shahrol Abd Wahil, Wong, Chin Mun, Abdullah Aliff Abdul Wahab, Hasni Ja’afar

Pertanika Journal of Science & Technology, 2020;28(3):859-878.
MyJurnal

Malaysia is the world’s third largest exporter of liquified natural gas and the second largest oil and natural gas producer in Southeast Asia, following Indonesia. The potential air pollutants released from the industry may affect the health of the population. The primary objective of this study was to determine the potential health risk among the population in the zone of impact. This was a comparative case study between controlled and uncontrolled emissions based on the air dispersion modelling. Hazard quotient (HQ) was used to assess non-carcinogenic risk, while lifetime cancer risk (LCR) was used to assess carcinogenic risk. All ambient air pollutant levels were within permissible levels and adhered to the standard. The HQ for hydrogen sulphide and benzene was less than one in all scenarios. The LCR for benzene was acceptable in all scenarios. Advanced pollution prevention equipment should be installed within the gas emission system to treat the final emission to meet prescribed permissible limits. Continuous ambient air monitoring and effective control measures should be practiced to ensure the sustainability of clean air. The health risk assessment showed no risk of developing malignancy and non-cancer disorder among the workers and general population living surround the petrochemical plants. This allows the development of the petroleum refinery plants to be continued.

Matched MeSH terms: Carcinogens
Health Risk Assessment of Heavy Metal in Urban Surface Soil (Klang District, Malaysia)

Yuswir NS, Praveena SM, Aris AZ, Ismail SN, Hashim Z

Bull Environ Contam Toxicol, 2015 Jul;95(1):80-9.
PMID: 25904089 DOI: 10.1007/s00128-015-1544-2

Urban environmental quality is vital to be investigated as the majority of people live in cities. However, given the continuous urbanization and industrialization in urban areas, heavy metals are continuously emitted into the terrestrial environment and pose a great threat to human. In this study, a total of 76 urban surface soil samples were collected in the Klang district (Malaysia), and analyzed for total and bioavailable heavy metal concentrations by inductively coupled plasma-optical emission spectrometry. Results showed that the concentrations of bioavailable heavy metals declined in the order of Al, Fe, Zn, Cu, Co, Cd, Pb, and Cr, and the concentrations of total heavy metals declined in the order of Fe, Al, Cu, Zn, Pb, Cr, Co, and Cd. Principal component analysis (PCA) showed that heavy metals could be grouped into three principal components, with PC1 containing Al and Fe, PC2 comprising Cd, Co, Cr, and Cu, and PC3 with only Zn. PCA results showed that PC1 may originate from natural sources, whereas PC2 and PC3 most likely originated from anthropogenic sources. Health risk assessment indicated that heavy metal contamination in the Klang district was below the acceptable threshold for carcinogenic and non-carcinogenic risks in adults, but above the acceptable threshold for carcinogenic and non-carcinogenic risks in children.

Matched MeSH terms: Carcinogens/analysis

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