Discovery of 2-Aminothiazole-4-carboxylic Acids as Broad-Spectrum Metallo-ß-lactamase Inhibitors by Mimicking Carbapenem Hydrolysate Binding.

Metallo-ß-lactamases (MBLs) are zinc-dependent enzymes capable of hydrolyzing all bicyclic ß-lactam antibiotics, posing a great threat to public health. However, there are currently no clinically approved MBL inhibitors. Despite variations in their active sites, MBLs share a common catalytic mechanism with carbapenems, forming similar reaction species and hydrolysates. We here report the development of 2-aminothiazole-4-carboxylic acids (AtCs) as broad-spectrum MBL inhibitors by mimicking the anchor pharmacophore features of carbapenem hydrolysate binding. Several AtCs manifested potent activity against B1, B2, and B3 MBLs. Crystallographic analyses revealed a common binding mode of AtCs with B1, B2, and B3 MBLs, resembling binding observed in the MBL-carbapenem product complexes. AtCs restored Meropenem activity against MBL-producing isolates. In the murine sepsis model, AtCs exhibited favorable synergistic efficacy with Meropenem, along with acceptable pharmacokinetics and safety profiles. This work offers promising lead compounds and a structural basis for the development of potential drug candidates to combat MBL-mediated antimicrobial resistance.

Metal binding pharmacophore click-derived discovery of new broad-spectrum metallo-ß-lactamase inhibitors.

The emergence of metallo-ß-lactamases (MBLs) confers resistance to nearly all the ß-lactam antibiotics, including carbapenems. Currently, there is a lack of clinically useful MBL inhibitors, making it crucial to discover new inhibitor chemotypes that can potently target multiple clinically relevant MBLs. Herein we report a strategy that utilizes a metal binding pharmacophore (MBP) click approach to identify new broad-spectrum MBL inhibitors. Our initial investigation identified several MBPs including phthalic acid, phenylboronic acid and benzyl phosphoric acid, which were subjected to structural transformations using azide-alkyne click reactions. Subsequent structure-activity relationship analyses led to the identification of several potent broad-spectrum MBL inhibitors, including 73 that manifested IC50 values ranging from 0.00012 µM to 0.64 µM against multiple MBLs. Co-crystallographic studies demonstrated the importance of MBPs in engaging with the MBL active site anchor pharmacophore features, and revealed the unusual two-molecule binding modes with IMP-1, highlighting the critical role of flexible active site loops in recognizing structurally diverse substrates/inhibitors. Our work provides new chemotypes for MBL inhibition and establishes a MBP click-derived paradigm for inhibitor discovery targeting MBLs as well as other metalloenzymes.

Metallo-ß-lactamase-mediated antimicrobial resistance and progress in inhibitor discovery.

Resistance to ß-lactam antibiotics is rapidly growing, substantially due to the spread of serine-ß-lactamases (SBLs) and metallo-ß-lactamases (MBLs), which efficiently catalyse ß-lactam hydrolysis. Combinations of a ß-lactam antibiotic with an SBL inhibitor have been clinically successful; however, no MBL inhibitors have been developed for clinical use. MBLs are a worrying resistance vector because they catalyse hydrolysis of all ß-lactam antibiotic classes, except the monobactams, and they are being disseminated across many bacterial species worldwide. Here we review the classification, structures, substrate profiles, and inhibition mechanisms of MBLs, highlighting current clinical problems due to MBL-mediated resistance and progress in understanding and combating MBL-mediated resistance.

New ε-N-thioglutaryl-lysine derivatives as SIRT5 inhibitors: Chemical synthesis, kinetic and crystallographic studies.

SIRT5 has been implicated in various physiological processes and human diseases, including cancer. Development of new highly potent, selective SIRT5 inhibitors is still needed to investigate disease-related mechanisms and therapeutic potentials. We here report new ε-N-thioglutaryllysine derivatives, which were designed according to SIRT5-catalysed deacylation reactions. These ε-N-thioglutaryllysine derivatives displayed potent SIRT5 inhibition, of which the potential photo-crosslinking derivative 8 manifested most potent inhibition with an IC50 value of 120 nM to SIRT5, and low inhibition to SIRT1-3 and SIRT6. The enzyme kinetic assays revealed that the ε-N-thioglutaryllysine derivatives inhibit SIRT5 by lysine-substrate competitive manner. Co-crystallographic analyses demonstrated that 8 binds to occupy the lysine-substate binding site by making hydrogen-bonding and electrostatic interactions with SIRT5-specific residues, and is likely positioned to react with NAD+ and form stable thio-intermediates. Compound 8 was observed to have low photo-crosslinking probability to SIRT5, possibly due to inappropriate position of the diazirine group as observed in SIRT5:8 crystal structure. This study provides useful information for developing drug-like inhibitors and cross-linking chemical probes for SIRT5-related studies.

Design, Synthesis, and Biological Evaluation of New 1H-Imidazole-2-Carboxylic Acid Derivatives as Metallo-ß-Lactamase Inhibitors.

As one of important mechanisms to ß-lactam antimicrobial resistance, metallo-ß-lactamases (MBLs) have been receiving increasing worldwide attentions. Ambler subclass B1 MBLs are most clinically relevant, because they can hydrolyze almost all ß-lactams with the exception of monobactams. However, it is still lacking of clinically useful drugs to combat MBL-medicated resistance. We previously identified 1H-imidazole-2-carboxylic acid as a core metal-binding pharmacophore (MBP) to target multiple B1 MBLs. Herein, we report structural optimization of 1H-imidazole-2-carboxylic acid and substituents. Structure-activity relationship (SAR) analyses revealed that replacement of 1H-imidazole-2-carboxylic acid with other structurally highly similar MBPs excepting thiazole-4-carboxylic acid resulted in decreased MBL inhibition. Further SAR studies identified more potent inhibitors to MBLs, of which 28 manifested IC50 values of 0.018 µM for both VIM-2 and VIM-5. The microbiological tests demonstrated that the most tested compounds showed improved synergistic effects; some compounds at 1 µg/ml were able to reduce meropenem MIC by at least 16-fold, which will be worth further development of new potent inhibitors particularly targeting VIM-type MBLs.

[Composition changes reveal relationship between color and enzymatic reaction of Magnoliae Officinalis Cortex during "sweating" process].

In this study, we employed Q Exactive to determine the main differential metabolites of Magnoliae Officinalis Cortex du-ring the "sweating" process. Further, we quantified the color parameters and determined the activities of polyphenol oxidase(PPO), peroxidase(POD), and tyrosinase of Magnoliae Officinalis Cortex during the "sweating" process. Gray correlation analysis was performed for the color, chemical composition, and enzyme activity to reveal the effect of enzymatic reaction on the color of Magnoliae Officinalis Cortex during the "sweating" process. Magnoliae Officinalis Cortex sweating in different manners showed similar metabolite changes. The primary metabolites that changed significantly included amino acids, nucleotides, and sugars, and the secondary metabolites with significant changes were phenols and phenylpropanoids. Despite the different sweating methods, eleven compounds were commonly up-regulated, including L-glutamic acid, acetylarginine, hypoxanthine, and xanthine; six compounds were commonly down-re-gulated, including L-arginine, L-aspartic acid, and phenylalanine. The brightness value(L~*), red-green value(a~*), and yellow-blue value(b~*) of Magnoliae Officinalis Cortex kept decreasing during the "sweating" process. The changes in the activities of PPO and POD during sweating were consistent with those in the color parameter values. The gray correlation analysis demonstrated that the main differential metabolites such as amino acids and phenols were closely related to the color parameters L~*, a~* and b~*; POD was correlated with amino acids and phenols; PPO had strong correlation with phenols. The results indicated that the color change of Magnoliae Officinalis Cortex during "sweating" was closely related to the reactions of enzymes dominated by PPO and POD. The study analyzed the correlations among the main differential metabolites, color parameters, and enzyme activities of Magnoliae Officinalis Cortex in the "sweating" process. It reveals the common law of material changes and ascertains the relationship between color changes and enzymatic reactions of Magnoliae Officinalis Cortex during "sweating". Therefore, this study provides a reference for studying the "sweating" mechanism of Magnoliae Officinalis Cortex and is of great significance to guarantee the quality of Magnoliae Officinalis Cortex.

Structure-guided optimization of 1H-imidazole-2-carboxylic acid derivatives affording potent VIM-Type metallo-ß-lactamase inhibitors.

Production of metallo-ß-lactamases (MBLs) in bacterial pathogens is an important cause of resistance to the 'last-resort' carbapenem antibiotics. Development of effective MBL inhibitors to reverse carbapenem resistance in Gram-negative bacteria is still needed. We herein report X-ray structure-guided optimization of 1H-imidazole-2-carboxylic acid (ICA) derivatives by considering how to engage with the active-site flexible loops and improve penetration into Gram-negative bacteria. Structure-activity relationship studies revealed the importance of appropriate substituents at ICA 1-position to achieve potent inhibition to class B1 MBLs, particularly the Verona Integron-encoded MBLs (VIMs), mainly by involving ingenious interactions with the flexible active site loops as observed by crystallographic analyses. Of the tested ICA inhibitors, 55 displayed potent synergistic antibacterial activity with meropenem against engineered Escherichia coli strains and even intractable clinically isolated Pseudomonas aeruginosa producing VIM-2 MBL. The morphologic and internal structural changes of bacterial cells after treatment further demonstrated that 55 crossed the outer membrane and reversed the activity of meropenem. Moreover, 55 showed good pharmacokinetic and safety profile in vivo, which could be a potential candidate for combating VIM-mediated Gram-negative carbapenem resistance.

Discovery of new human Sirtuin 5 inhibitors by mimicking glutaryl-lysine substrates.

Human sirtuin 5 (SIRT5) plays pivotal roles in metabolic pathways and other biological processes, and is involved in several human diseases including cancer. Development of new potent and selective SIRT5 inhibitors is currently desirable to provide potential therapeutics for related diseases. Herein, we report a series of new 3-thioureidopropanoic acid derivatives, which were designed to mimic the binding features of SIRT5 glutaryl-lysine substrates. Structure-activity relationship studies revealed several compounds with low micromolar inhibitory activities to SIRT5. Computational and biochemical studies indicated that these compounds exhibited competitive SIRT5 inhibition with respect to the glutaryl-lysine substrate rather than nicotinamide adenine dinucleotide cofactor. Moreover, they showed high selectivity for SIRT5 over SIRT1-3 and 6 and could stabilize SIRT5 proteins as revealed by thermal shift analyses. This work provides an effective substrate-mimicking strategy for future inhibitor design, and offers new inhibitors to investigate their therapeutic potentials in SIRT5-associated disease models.

ProfKin: A comprehensive web server for structure-based kinase profiling.

Protein kinases are central mediators of signal-transduction cascades and attractive drug targets for therapeutic intervention. Since kinases are structurally and mechanistically related to each other, kinase inhibitor selectivity is often investigated by kinase profiling and considered as an important index for drug discovery. We here describe a versatile web server termed ProfKin for structure-based kinase profiling, which is based on a kinase-ligand focused database (KinLigDB). It provides all ready-to-use 3D structure coordinates of 4219 kinase-ligand complex structures covering 297 human kinases and the associated information, particularly including binding site type, binding ligand type, interaction fingerprints, downstream molecules and related human diseases. The web server works via predicting possible binding modes for the query molecule, prioritizing the binding modes guided by an interaction fingerprint analysis method, and giving a list of ranked kinases by a comprehensive index. Users can freely select entire or part of the KinLigDB database, e.g. via subfamily and binding site type, to customize the profiling contents. The superimpositions of the predicted binding poses of the query molecule with reference binding modes can be visually inspected on the website. The additional classification attributes and phylogenetic tree are also given for each top-ranked kinase.

Design and enantioselective synthesis of 3-(α-acrylic acid) benzoxaboroles to combat carbapenemase resistance.

Chiral 3-substituted benzoxaboroles were designed as carbapenemase inhibitors and efficiently synthesised via asymmetric Morita-Baylis-Hillman reaction. Some of the benzoxaboroles were potent inhibitors of clinically relevant carbapenemases and restored the activity of meropenem in bacteria harbouring these enzymes. Crystallographic analyses validate the proposed mechanism of binding to carbapenemases, i.e. in a manner relating to their antibiotic substrates. The results illustrate how combining a structure-based design approach with asymmetric catalysis can efficiently lead to potent ß-lactamase inhibitors and provide a starting point to develop drugs combatting carbapenemases.

Discovery of 3-aryl substituted benzoxaboroles as broad-spectrum inhibitors of serine- and metallo-ß-lactamases.

The production of ß-lactamases represents the main cause of resistance to clinically important ß-lactam antibiotics. Boron containing compounds have been demonstrated as promising broad-spectrum ß-lactamase inhibitors to combat ß-lactam resistance. Here we report a series of 3-aryl substituted benzoxaborole derivatives, which manifested broad-spectrum inhibition to representative serine-ß-lactamases (SBLs) and metallo-ß-lactamases (MBLs). The most potent inhibitor 9f displayed an IC50 value of 86 nM to KPC-2 SBL and micromolar inhibitory activity towards other tested enzymes. Cell-based assays further revealed that 9f was able to significantly reduce the MICs of meropenem in clinically isolated KPC-2-producing bacterial strains and it showed no apparent toxicity in HEK293T cells.

[Comparative transcriptome and proteome profiling of chlorophyll metabolism pathway in four types of Magnolia officinalis].

Magnolia officinalis is a traditional Chinese medicine,with many years of cultivating process, M. officinalis leaves show more differentiation types due to the exchange of seeds from different provenances. "Da Ao"(DA), "Xiao Ao"(XA), "Chuan Hou"(CH),and "Liu Ye"(LY)are the main types of M. officinalis in Sichuan province of China,and there were obvious differences in growth rate,chemical composition,leaf shape and leaf colour. This study selected different types of M. officinalis leaves(DA,XA,LY and CH)from Sichuan to determine their chlorophyll content. Transcriptomic level sequencing of different types of M. officinalis leaf tissues was by high-throughput sequencing analysis and proteomics used an integrated approach involving TMT labelling and LC-MS/MS to quantify the dynamic changes of the whole proteome of M. officinalis. The results showed that CH had the lowest chlorophyll content while DA had the highest chlorophyll content. Furthermore,transcriptome and proteomics results showed that chlorophyll synthesis pathway in DA glutamine-tRNA reductase,urinary porphyrins decarboxylase(UROD),oxygen-dependent protoporphyrin(ODCO),the original-Ⅲ oxidase protoporphyrin oxidase(PPO),magnesium chelating enzyme subunit ChlD,protoporphyrin magnesium Ⅸ monomethyl ester [oxidative] cyclase(MPPMC)were significantly higher than CH,XA and LY,consistent in the results of determination of chlorophyll content(chlorophyll content was highest of 37.56 mg·g~(-1) FW). Some rate-limiting enzymes related to the chlorophyll synthesis,such as ODCO,PPO and MPPMC were tested by Parallel Reaction Monitoring(PRM),and the results showed that the rate-limiting enzyme content in DA was higher than that in other three types. Therefore,based on the differences in leaf color of four types of M. officinalis,the research conducted a preliminary study on the chlorophyll metabolism pathway in leaves of different types of M. officinalis,and explored relevant genes and proteins causing leaf color differences from the molecular level,so as to lay a foundation for studying the differences in growth and development of different types of M. officinalis.

Sensitive fluorogenic substrates for sirtuin deacylase inhibitor discovery.

Sirtuins (SIRTs) are NAD+-dependent lysine deacylases, regulating many important biological processes such as metabolism and stress responses. SIRT inhibitors may provide potential benefits against SIRT-driven human diseases. Development of efficient assay platforms based on fluorogenic substrates will facilitate the discovery of high-quality SIRT inhibitors. We here report 16 new fluorogenic peptide substrates (P1-P16) designed with structurally diverse tetrapeptides and acyl modifications. Tests of P1-P16 against SIRT isoforms identified several sensitive substrates for SIRT1, SIRT2, SIRT3 and SIRT5, which manifested lower KM values and higher catalytic efficiency, and particularly had less signal interference in inhibitor screening compared with our previously reported internally quenched fluorescent substrates. Co-crystallization of sensitive substrates P13 and P15 with SIRT5 revealed an unexpected binding mode, involving interactions with residues from active site bordering surfaces, different from that observed for other peptides derived from natural protein substrates. By using SIRT5 sensitive substrates, we found that TW-37, a Bcl-2 inhibitor, displayed low micromolar inhibition to SIRT5, which was further validated by isothermal titration calorimetry analyses, offering a new point to develop dual-action SIRT5/Bcl-2 inhibitors against cancers. This work provides assay platform and structural basis for developing new substrates and inhibitors targeting human SIRTs.

Principles and current strategies targeting metallo-ß-lactamase mediated antibacterial resistance.

Resistance to ß-lactam antibacterials is commonly associated with the production of the serine ß-lactamases (SBLs) and/or metallo-ß-lactamases (MBLs). Although clinically useful inhibitors for the SBLs have been developed, no equivalent inhibitors are available for the MBLs, which can hydrolyze almost all ß-lactam antibiotics, including the so-called "last resort" carbapenems. It is still a challenging task to develop a clinically useful inhibitor that should be broad-spectrum targeting multiple clinically relevant MBL enzymes that differ in their active site features. This review provides a detailed description of interaction modes of substrates and small-molecule inhibitors with various MBL enzymes and highlights the importance of metal- and "anchor residue"-binding features to achieve broad-spectrum MBL inhibition. Recently emerging active site interference strategies include metal ion deprivation, metal ion replacement, and cysteine modification as challenging, but worth experimenting directions for inhibitor development. The metalloenzyme selectivity, metal-binding pharmacophore, and cellular permeability and accumulation should be properly considered in the further development of clinically useful inhibitors to combat MBL-mediated antibacterial resistance.

Discovery of mercaptopropanamide-substituted aryl tetrazoles as new broad-spectrum metallo-ß-lactamase inhibitors.

ß-Lactam antibiotic resistance mediated by metallo-ß-lactamases (MBL) has threatened global public health. There are currently no available inhibitors of MBLs for clinical use. We previously reported the ruthenium-catalyzed meta-selective C-H nitration synthesis method, leading to some meta-mercaptopropanamide substituted aryl tetrazoles as new potent MBL inhibitors. Here, we described the structure-activity relationship of meta- and ortho-mercaptopropanamide substituted aryl tetrazoles with clinically relevant MBLs. The resulting most potent compound 13a showed IC50 values of 0.044 µM, 0.396 µM and 0.71 µM against VIM-2, NDM-1 and IMP-1 MBL, respectively. Crystallographic analysis revealed that 13a chelated to active site zinc ions via the thiol group and interacted with the catalytically important residues Asn233 and Tyr67, providing further structural information for the development of thiol based MBL inhibitors.

MeLAD: an integrated resource for metalloenzyme-ligand associations.

MOTIVATION: Metalloenzymes are attractive targets for therapeutic intervention owing to their central roles in various biological processes and pathological situations. The fast-growing body of structural data on metalloenzyme-ligand interactions is facilitating efficient drug discovery targeting metalloenzymes. However, there remains a shortage of specific databases that can provide centralized, interconnected information exclusive to metalloenzyme-ligand associations. RESULTS: We created a Metalloenzyme-Ligand Association Database (MeLAD), which is designed to provide curated structural data and information exclusive to metalloenzyme-ligand interactions, and more uniquely, present expanded associations that are represented by metal-binding pharmacophores (MBPs), metalloenzyme structural similarity (MeSIM) and ligand chemical similarity (LigSIM). MeLAD currently contains 6086 structurally resolved interactions of 1416 metalloenzymes with 3564 ligands, of which classical metal-binding, non-classical metal-binding, non-metal-binding and metal water-bridging interactions account for 63.0%, 2.3%, 34.4% and 0.3%, respectively. A total of 263 monodentate, 191 bidentate and 15 tridentate MBP chemotypes were included in MeLAD, which are linked to different active site metal ions and coordination modes. 3726 and 52 740 deductive metalloenzyme-ligand associations by MeSIM and LigSIM analyses, respectively, were included in MeLAD. An online server is provided for users to conduct metalloenzyme profiling prediction for small molecules of interest. MeLAD is searchable by multiple criteria, e.g. metalloenzyme name, ligand identifier, functional class, bioinorganic class, metal ion and metal-containing cofactor, which will serve as a valuable, integrative data source to foster metalloenzyme related research, particularly involved in drug discovery targeting metalloenzymes. AVAILABILITY AND IMPLEMENTATION: MeLAD is accessible at https://melad.ddtmlab.org. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Structure-Based Development of (1-(3'-Mercaptopropanamido)methyl)boronic Acid Derived Broad-Spectrum, Dual-Action Inhibitors of Metallo- and Serine-ß-lactamases.

The emergence and spread of bacterial pathogens acquired metallo-ß-lactamase (MBL) and serine-ß-lactamase (SBL) medicated ß-lactam resistance gives rise to an urgent need for the development of new dual-action MBL/SBL inhibitors. Application of a pharmacophore fusion strategy led to the identification of (2'S)-(1-(3'-mercapto-2'-methylpropanamido)methyl)boronic acid (MS01) as a new dual-action inhibitor, which manifests broad-spectrum inhibition to representative MBL/SBL enzymes, including the widespread VIM-2 and KPC-2. Guided by the VIM-2:MS01 and KPC-2:MS01 complex structures, further structural optimization yielded new, more potent dual-action inhibitors. Selectivity studies indicated that the inhibitors had no apparent inhibition to human angiotensin-converting enzyme-2 and showed selectivity across serine hydrolyases in E. coli and human HEK293T cells labeled by the activity-based probe TAMRA-FP. Moreover, the inhibitors displayed potentiation of meropenem efficacy against MBL- or SBL-positive clinical isolates without apparent cytotoxicity. This work will aid efforts to develop new types of clinically useful dual-action inhibitors targeting MBL/SBL enzymes.

Crystallographic and SAR analyses reveal the high requirements needed to selectively and potently inhibit SIRT2 deacetylase and decanoylase.

A high-quality X-ray crystal structure reveals the mechanism of compound 1a inhibiting SIRT2 deacetylase and decanoylase. Structure-activity relationship (SAR) analysis of the synthesized derivatives of 1a reveals the high requirements needed for selective inhibitors to bind with the induced hydrophobic pocket and potently inhibit sirtuin 2 deacetylase.

[Dynamic response and variance of vegetation in China from 1982 to 2015 under the asymmetric rate of temperature fluctuation.] / 1982­2015年昼夜不对称增温下中国自然植被动态响应及差异.

The impact of global warming on the growth and development of natural vegetation is an important concern worldwide. Based on the data from the vegetation normalization index, daytime temperature (Tmax), nighttime temperature (Tmin), precipitation, and elevation from 1982 to 2015, we examined the day-night warming response of 42 types of natural vegetation in China. The results showed that both the temperature at day and night was significantly increased in the study area, with obvious asymmetry. The night warming was about 1.6 times as high as that at daytime. The Tmin was more conducive to vegetation growth than the Tmax. The proportion of vegetation types with positive relationship with Tmin was greater than the Tmax, with significant spatial difference. Subtropical vegetation accounted for 85.7% of vegetation with positive correlation with Tmax. The temperate alpine, mountainous, and desert vegetation responded more positively to Tmin. The increase of Tmin was not conducive to the growth and development of vegetation at high altitudes, while that of Tmax was the opposite. The correlations of vegetation growth with Tmax and Tmin were as follows: steppe > meadow > needleleaf forest > desert vegetation > broadleaf forest; meadow > desert vegetation > broadleaf forest > steppe > needleleaf forest.

[Pollution Characteristics and Health Risk Assessment of Heavy Metals in Wheat Grains Cultivated in Kaifeng Irrigation Area of the Yellow River].

In order to monitor heavy metal pollution in agricultural soils and assess the corresponding health risk in the Yellow River irrigation area, this study applied the Nemero index and the health risk index to evaluate heavy metal pollution in wheat grains and the health risks for residents in the lower reaches of the Yellow River. Four towns in Kaifeng, which are within the lower reaches of the Yellow River, were selected as the study area. The examination of wheat samples revealed that the average contents of Cd, Cr, Pb, Cu, Zn, Ni, and Hg in the wheat grains were 0.034, 0.428, 0.279, 5.363, 29.605, 0.305, and 0.003 mg·kg-1, respectively. Among the heavy metals, Pb and Zn exceeded the national food hygiene standards. The pollution indices of Pb and Zn in the wheat grains contributed significantly to the comprehensive pollution index, as each was greater than 1 (1.985), although the pollution indices of the other heavy metals were less than 1. The comprehensive pollution index of wheat in each town ranged from 1.116 to 1.847. The health risk indices of non-carcinogenic heavy metals (Pb, Cu, Zn, and Hg) for adults and children were 1.0558 and 0.5450, respectively. The health risk indices of carcinogenic heavy metals (Cd, Cr, and Ni) for adults and children were higher than the maximum acceptable risk level (1×10-4) recommended by the USEPA, which suggests that residents of the study area have a high risk of developing various forms of cancer.