Evaluation of oxidative stress and DNA damage in traffic policemen exposed to vehicle exhaust.

OBJECTIVE: We aimed to study the genotoxic effects in traffic police who are occupationally exposed due to higher free radical generation. METHODS: Ambient and breathing zone air samples were analyzed blood samples were collected for analysis of antioxidant enzymes Superoxide Dismutase (SOD), Glutathione Peroxidase (GPx) and free radicals - nitric oxide (NO) and malondialdehyde (MDA) levels using a spectrophotometer. DNA damage was measured with the comet assay. RESULTS: Higher levels of benzene (BZ), toluene (TOL), carbon monoxide (CO), benzo([a])pyrene (BaP) and sulfur dioxide (SO2) was observed in traffic police. Elevated levels of NO, MDA and comet tail length and lower SOD and GPx levels observed in traffic police. CONCLUSION: The studied biomarkers, related to oxidative stress and DNA damage positively correlated in traffic police exposed to environmental air pollutants.

Assessment of 8-oxo-7, 8-dihydro-2'-deoxyguanosine and malondialdehyde levels as oxidative stress markers and antioxidant status in non-small cell lung cancer.

OBJECTIVE: The present investigation was taken up to evaluate the 8-oxo-7,8-dihydro-2'-deoxyguanosine and malondialdehyde as markers of oxidative stress, the levels of antioxidants and the correlations between these oxidative stress markers and antioxidants in lung cancer patients. METHODS: The study included 222 patients (158 men and 64 women, age ranging from 32 to 85 years) and 207 control subjects (153 men and 54 women, aged 30-80 years) for the analysis of urinary excretion of 8-oxodG using an ELISA assay, plasma malondialdehyde using spectrophotometer and red cell Cu-Zn SOD and GPx activities by kit methods. RESULTS: The levels of 8-oxodG and malondialdehyde were significantly higher (p < 0.001) and red cell superoxide dismutase and glutathione peroxidase activities (p < 0.001) were significantly lower in lung cancer patients than in controls. There was a significantly positive correlation between 8-oxodG and malondialdehyde (r=0.912, p < 0.001) and a negative correlation between 8-oxodG and antioxidants. CONCLUSIONS: Our results demonstrate that an increased rate of oxidative stress might play a role in the pathogenesis of lung cancer as evidenced by a failure in the oxidant/antioxidant balance in favour of lipid peroxidation and DNA damage.

Association of eNOS and ACE gene polymorphisms and plasma nitric oxide with risk of non-small cell lung cancer in South India.

INTRODUCTION: The role of ACE and eNOS gene polymorphisms and their association with various cancers were reported. However, their role in the lung cancer is unclear. OBJECTIVES: In this study, we analyzed eNOS and ACE gene polymorphisms and the risk of non-small cell lung cancer (NSCLC) in South Indian population. RESULTS: For the eNOS gene, the homozygous "AA" genotypic frequency was significantly associated with NSCLC with an overall risk of 3.6-fold (P = 0.006, odds ratio = 3.58, 95% confidence interval = 1.66, 7.723). The heterozygous "I/D" genotypic frequency of ACE gene was significantly higher in NSCLC patients when compared to the controls with a 2.29-fold risk for NSCLC. Multiple regression analyses indicated that gender, smoking status, and polymorphisms in eNOS and ACE genes as the strongest predicting factors for an increased susceptibility to NSCLC. CONCLUSIONS: We report for the first time that polymorphisms in the eNOS "A/A" (homozygous mutant) and ACE "I/D" genotypes might contribute to the increased risk of NSCLC in the South Indian population.

Molecular dynamic simulations reveal suboptimal binding of salbutamol in T164I variant of ß2 adrenergic receptor.

The natural variant C491T (rs1800088) in ADRB2 gene substitutes Threonine to Isoleucine at 164th position in ß2AR and results in receptor sequestration and altered binding of agonists. Present investigation pursues to identify the effect of T164I variation on function and structure of ß2AR through systematic computational approaches. The study, in addition, addresses altered binding of salbutamol in T164I variant through molecular dynamic simulations. Methods involving changes in free energy, solvent accessibility surface area, root mean square deviations and analysis of binding cavity revealed structural perturbations in receptor to incur upon T164I substitution. For comprehensive understanding of receptor upon substitution, OPLS force field aided molecular dynamic simulations were performed for 10 ns. Simulations revealed massive structural departure for T164I ß2AR variant from the native state along with considerably higher root mean square fluctuations of residues near the cavity. Affinity prediction by molecular docking showed two folds reduced affinity of salbutamol in T164I variant. To validate the credibility docking results, simulations for ligand-receptor complex were performed which demonstrated unstable salbutamol-T164I ß2AR complex formation. Further, analysis of interactions in course of simulations revealed reduced ligand-receptor interactions of salbutamol in T164I variant. Taken together, studies herein provide structural rationales for suboptimal binding of salbutamol in T164I variant through integrated molecular modeling approaches.

Association of CnB 5I/5D promoter gene polymorphism and serum calcineurin levels in early onset of coronary artery disease of south Indian cohort.

Calcineurin, a serine/threonine phosphatase is a calcium dependent protein which on activation triggers transcriptional up regulation of inflammatory genes associated with inflammation in the arteries and progressive formation of plaques in CAD. The present investigation is aimed to study the possible association of Calcineurin encoding gene PPP3R1 (CnB 5I/5D) polymorphism in correlation with serum levels of calcineurin in coronary artery disease (CAD). A total of 300 angiographically documented CAD patients and 300 age, gender ethnicity matched healthy controls were recruited for the study. Serum Calcineurin levels were estimated by enzyme-linked immunosorbent assay (ELISA) and genotypes were determined based on PCR-RFLP. The CnB 5I/5D variation was found to be significantly associated with CAD (p<0.03), correlated to elevated serum calcineurin levels encoded by (<0.01) 5I/5D allele authenticated by Insilco analysis. Multiple logistic regression analysis also confirmed these findings [adjusted OR for DD genotype was 3.19 (95% CI 1.40-7.24) and p=0.001]. The results suggest that 5-base pair deletion results in increased serum calcineurin levels and may trigger up regulation of calcineurin which mediates vascular inflammation and atherosclerosis in CAD.

Association of CYP1A1, GSTM1 and GSTT1 gene polymorphisms with risk of non-small cell lung cancer in Andhra Pradesh region of South India.

BACKGROUND: Lung cancer is one of the most preventable causes of death globally both in developed and developing countries. Although it is well established that smokers develop lung cancer, there are some smokers who are free from the disease risk. The predisposition to lung cancer is attributed to genetic polymorphisms in xenobiotic metabolizing genes. Reports on assessment of xenobiotic metabolizing genes like Cytochrome P 450 1A1 (CYP1A1), Glutathione -S -transferase M1 (GSTM1) and T1 (GSTT1) polymorphisms from India are meagre, and reports from Andhra Pradesh are lacking. METHODS AND RESULTS: Assessment of polymorphisms in CYP1A1, GSTM1 and GSTT1 in NSCLC patients and healthy individuals specific to population of Andhra Pradesh, a South Indian state was attempted by multiplex PCR and RFLP, and this is the first study which tried to correlate oxidative stress with the polymorphisms in xenobiotic metabolizing genes. Results showed that CYP1A1 m1 'CC' genotype was significantly associated with lung cancer susceptibility with a 2.3-fold risk, CYP1A1 m2 'AG' gene polymorphisms with 8.8-fold risk and GSTT1 (-/-) genotype demonstrated a twofold risk of disease susceptibility. CONCLUSIONS: A combined role of genetic polymorphisms and smoking status can be attributed for the cause of lung cancer. Further, the association between oxidative stress and genetic polymorphisms showed a correlation between GSTT1 and super oxide dismutase activity; CYP1A1 m1, m2 and GSTT1 with glutathione peroxidase activity; CYP1A1 m1 and GSTM1 with melondialdehyde levels; and CYP1A1 m1 and GSTT1 with 8-oxo-7,8-dihydro-2'-deoxyguanosine. A higher risk of lung cancer seems to be associated with combined gene polymorphisms of phase I and phase II enzymes than that ascribed to single gene polymorphism.

Identification of Small Molecule as a High Affinity β2 Agonist Promiscuously Targeting Wild and Mutated (Thr164Ile) β 2 Adrenergic Receptor in the Treatment of Bronchial Asthma.

BACKGROUND: A subset of asthmatics shows refractoriness to Salbutamol owing to ADRB2 gene C.T polymorphism (rs 1800888) that substitutes Thr to Ile at the position 164 in the ß2 adrenergic receptor leading to sub-optimal binding of Salbutamol. The present study aims to associate the Salbutamol (200 mcg) refractoriness with the polymorphism and select the best existing agonist with optimal binding affinity against wild and mutated receptor and further identify high affinity compound, irrespectively targeting wild and mutated receptor through virtual screening methods. METHODS: Responders to Salbutamol were categorized, if percentage reversibility was greater than or equal to 12% in them, while those showing reversibility less than 12% were non-responders. The genotyping for polymorphism was performed by ARMS PCR method. Established agonists with consistent binding affinity against wild and mutated receptors formed query compound to identify high affinity molecule from Phase database through 7 point pharmacophore based screening. RESULTS: Polymorphism was significantly associated with non-responders (p= < 0.05) demonstrating it as a major factor of Salbutamol refractoriness. Results from Glide Docking showed that Fenoterol had highest affinity for mutated receptor and stood as second best (after Salbutamol) high affinity agonist for wild receptor among the established ß2 agonists. Therefore Fenoterol formed a query molecule (7 point pharmacophore) in identification of high affinity compound for virtual screening process. CONCLUSION: Compound CACPD2011a-0001278239 identified through virtual screening against 4 million compounds in phase database was shown to irrespectively target both wild and mutated ß2 adrenergic receptor with high and consistent affinity which was par greater than established ß2agonists.

Association of Beta 2 adrenergic receptor (Thr164Ile) polymorphism with Salbutamol refractoriness in severe asthmatics from Indian population.

BACKGROUND: Thr164Ile polymorphism in the ADRB2 gene encoding ß2 adrenergic receptor (ß2AR) has its functional consequence in declining ligand-receptor interactions and depressed coupling of ß2AR to adenylcyclase. In the present study, we sought to evaluate the possible association of Thr164Ile polymorphism with asthma susceptibility, pharmacogenetic response to Salbutamol and varying degrees of severity. METHODS: Three hundred and ninety eight clinically diagnosed patients and four hundred and fifty six healthy controls were enrolled in the study. Patients were classified into severity classes according to the Global Initiative for Asthma (GINA) guidelines. To assess bronchodilator response, spirometry was performed before and 15min after Salbutamol (200µg) delivery. Responders to Salbutamol were categorized if percentage reversibility was greater than or equal to 12% in them, while those showing reversibility <12% were classified as non-responders. Further, responding phenotypes were stratified into severity groups. Genotyping was carried out by ARMS-PCR technique. Statistical methods were applied to test the significance of the results. RESULTS: In the present study, polymorphism was not associated with disease susceptibility however; there was significant association with non-responding asthmatics. In case of severity subsets, the polymorphism was not associated with milder subtypes; although, notable association was observed with moderate and severe asthma subtypes. In addition, the polymorphism was significantly associated with non-responding patients with severe asthma. CONCLUSIONS: In south Indian population, the ADRB2 Thr164Ile polymorphism may not form susceptible variant to develop asthma, however, it can form a predictive maker for bronchodilator (Salbutamol) response in severe asthmatics.

Association of transforming growth factor-Beta 1 promoter variant -509 c/t with bronchial asthma in South Indian population.

Transforming growth factor-beta 1 (TGF-ß1) is a multifunctional cytokine that plays a pivotal role in airway remodeling observed in the asthmatic airways. C to T base substitution at -509 promoter position in the TGF-ß1 gene leads to its increased expression which contributes to airway remodeling in bronchial asthma. We sought to evaluate the association of TGF-ß1 -509 C/T promoter variant with clinical asthma and varying degrees of disease severity. Three hundred and eighty-two clinically diagnosed asthma patients and 410 healthy controls were enrolled for the study. Patients were classified into severity classes according to the Global Initiative for Asthma (GINA) guidelines. TGF-ß1 -509 C/T genotyping was carried out by amplification refractory mutation system polymerase chain reaction (ARMS-PCR) technique. In the present study, we found significantly higher frequency of TT genotype in asthma patients compared to controls (for TT vs. CC, p = 0.020). In addition, a significant difference was observed in the frequency of C and T allele in patients and controls (for T vs. C, p = 0.029). The heterozygous "CT" genotype was higher in moderate and severe asthmatics compared to mild subset of patients (for mild vs. moderate, p = 0.037). However, there was no significant distribution and association of variant allele with the severity subsets.

Analysis of ADRB2 (Arg16Gly) Gene Variant with Susceptibility, Pharmacogenetic Response and Disease Severity in South Indian Asthmatics.

ß2-Adrenergic receptor (ß2-AR) plays a crucial role in asthma pathophysiology by regulating, processes of the lung function, and clinical response to bronchodilators. The +46G>A- Gly16Arg polymorphism in the gene encoding ß2 adrenergic receptor (ADRB2) has been associated with receptor non-responsiveness after ß2-agonist exposure. In the present study, we sought to evaluate the possible association of Gly16Arg polymorphism with asthma susceptibility, pharmacogenetic response to Salbutamol, and varying degrees of disease severity. Three hundred ninety-eight clinically diagnosed patients and 456 healthy controls were enrolled for the study. Patients were classified into severity classes according to Global Initiative for Asthma guidelines. To assess bronchodilator response, spirometry was performed before and 15 min after Salbutamol (200 µg) delivery. Responders to Salbutamol were categorized if percentage reversibility was greater than or equal to 12% in them, while those showing reversibility less than 12% were classified as non-responders. Genotyping was carried out by ARMS-PCR technique. Statistical methods were applied to test for the significance of the results. In the present study, there was lack of significant association of polymorphism with disease susceptibility as well as with bronchodilator response. The polymorphism was not associated with mild and moderate asthma subtypes; however, there was a notable association with severe asthma subtype. In addition, the polymorphism was associated with severe asthma compared to subtypes of mild and moderate asthma combined. In a South Indian population, the ADRB2 Arg/Gly may not form a susceptible variant to develop asthma nor can be a standard predictive marker to bronchodilator response; nevertheless, the patterns in asthma severity can be predicted by analyzing this variant.

Identification of high affinity bioactive Salbutamol conformer directed against mutated (Thr164Ile) beta 2 adrenergic receptor.

Salbutamol forms an important and widely administered ß2 agonist prescribed in the symptomatic treatment of bronchial asthma. Unfortunately, a subset of patients show refractoriness to it owing to ADRB2 gene variant (rs 1800888). The variant substitutes Thr to Ile at the position 164 in the ß2 adrenergic receptor leading to sub-optimal binding of agonists. The present study aims to associate the Salbutamol response with the variant and select the bioactive conformer of Sabutamol with optimal binding affinity against mutated receptor by in silico approaches. To assess bronchodilator response spirometry was performed before and 15 min after Salbutamol (200 mcg) inhalation. Responders to Salbutamol were categorized if percentage reversibility was greater than or equal to 12%, while those showing FEV1 reversibility less than 12% were classified as non-responders. Among the 344 subjects screened, 238 were responders and 106 were non-responders. The frequency of mutant allele "T" was significantly higher in case of non-responders (p < 0.05). In silico process involved generation of Salbutamol conformer ensembles supported by systematic search algorithm. 4369 conformers were generated of which only 1882 were considered bioactive conformers (threshold RMSD≤1 in reference to normalized structure of salbutamol). All the bioactive conformers were evaluated for the binding affinity against (Thr164 Ile) receptor through MolDock aided docking algorithm. One of the bioactive conformer (P.E. = -57.0038, RMSD = 0.6) demonstrated 1.54 folds greater affinity than the normal Salbutamol in the mutated receptor. The conformer identified in the present study may be put to pharmacodynamic and pharmacokinetic studies in future ahead.

Identification and Pharmacological Analysis of High Efficacy Small Molecule Inhibitors of EGF-EGFR Interactions in Clinical Treatment of Non-Small Cell Lung Carcinoma: a Computational Approach.

Inhibition of EGFR-EGF interactions forms an important therapeutic rationale in treatment of non-small cell lung carcinoma. Established inhibitors have been successful in reducing proliferative processes observed in NSCLC, however patients suffer serious side effects. Considering the narrow therapeutic window of present EGFR inhibitors, the present study centred on identifying high efficacy EGFR inhibitors through structure based virtual screening strategies. Established inhibitors - Afatinib, Dacomitinib, Erlotinib, Lapatinib, Rociletinib formed parent compounds to retrieve similar compounds by linear fingerprint based tanimoto search with a threshold of 90%. The compounds (parents and respective similars) were docked at the EGF binding cleft of EGFR. Patch dock supervised protein-protein interactions were established between EGF and ligand (query and similar) bound and free states of EGFR. Compounds ADS103317, AKOS024836912, AGN-PC-0MXVWT, GNF-Pf-3539, SCHEMBL15205939 were retrieved respectively similar to Afatinib, Dacomitinib, Erlotinib, Lapatinib, Rociletinib. Compound- AGN-PC-0MXVWT akin to Erlotinib showed highest affinity against EGFR amongst all the compounds (parent and similar) assessed in the study. Further, AGN-PC-0MXVWT brought about significant blocking of EGFR-EGF interactions in addition showed appreciable ADMET properties and pharmacophoric features. In the study, we report AGN-PC-0MXVWT to be an efficient and high efficacy inhibitor of EGFR-EGF interactions identified through computational approaches.

Genetic instability in peripheral lymphocytes as biological marker for non-small cell lung cancer patients in the South Indian state of Andhra Pradesh.

OBJECTIVES: This study aims, first, at evaluating the DNA and chromosomal damage in non-small cell lung cancer (NSCLC) patients from the South Indian state of Andhra Pradesh, and then at correlating these results with possible confounding factors that might potentially play a role in causing genetic damage. METHODS: The study included 246 NSCLC patients (177 men and 69 women) and 250 healthy controls (180 men and 70 women) for the analysis of DNA and chromosomal damage using the comet assay and micronucleus test. RESULTS: Both DNA and chromosomal damage were found to be increased in NSCLC patients compared to healthy controls, and the extent of the damage was higher in males than female patients. The smoking status had a profound effect on the extent of DNA and chromosomal damage in NSCLC patients. The degree of genetic damage correlated with the stage of the disease. However, the histological status had no effect on the extent of DNA and chromosomal damage among NSCLC patients. CONCLUSIONS: We here report, for the first time, that the NSCLC patients selected form the Andhra Pradesh population had increased DNA damage and higher mean micronucleus frequencies in peripheral lymphocytes, indicating a strong background level of genetic instability.

Mutational analysis of JAG1 gene in non-syndromic tetralogy of Fallot children.

BACKGROUND: JAG1 is an evolutionarily conserved ligand for Notch receptor and functions in the cell fate decisions, cell-cell interactions throughout the development of heart especially right heart development. Tetralogy of Fallot (TOF) is essentially a right sided heart disease with characteristic features of ventricular septal defect, right ventricular outflow tract obstruction, aortic dextroposition and right ventricular hypertrophy. Hence, the present study was investigated to identify mutations of JAG1 gene in an Indian cohort of patients with TOF. METHODS: The clinical data and blood samples from 84 unrelated subjects with TOF were collected and evaluated in comparison with 87 healthy individuals. PCR based single strand conformation polymorphism analysis and subsequent bidirectional DNA sequencing of conformers was carried in the exon 6 of JAG1 gene. RESULTS: The DNA sequences aligned with NCBI-BLAST led to the identification of four novel variations including one nonsense 765 C>A, two missense 814 G>T, 834 G>T; and one silent alteration 816 G>T in TOF patients. The protein structure of JAG1 predicts that these variations effect first and second epidermal growth factor like repeat and might disturb ligand-receptor binding ability. The presence of similar variations was not observed in healthy controls. The software CLUSTAL-W showed the inter species conservation of altered amino acids in missense mutations. CONCLUSION: Disease-associating novel JAG1 gene variations were found in TOF patients, and seem to play an important role in the causation of the disease.