Dual approach: micellar delivery of chlorambucil prodrug with concurrent glutathione depletion and GST inhibition for enhanced anticancer activity.

Although chlorambucil (CHL) is a long-established anticancer drug, the drug failure of CHL, mediated by the intracellular defense system consisting of glutathione (GSH) and GSH S-transferase pi (GST-pi), has significantly limited the application of CHL. To overcome this issue, we first designed a GSH-responsive small-molecule prodrug (EA-SS-CHL) by combining CHL and ethacrynic acid (EA). Subsequently, drug-loaded nanoparticles (ECPP) were formed by the self-assembly between EA-SS-CHL and amphiphilic PEG-PDLLA to improve the water solubility of the prodrug and its ability to target tumor sites. Upon exposure to high intracellular GSH concentration, EA-SS-CHL gradually degrades, leading to the release of EA and CHL. The presence of EA facilitates the depletion of GSH and inhibition of GST-pi, ultimately attenuating the detoxification of the intracellular defense system to CHL. Cytotoxicity studies and apoptosis assays demonstrate that ECPP exhibits higher therapeutic efficiency than CHL. Additionally,in vivotumor suppression effects and biocompatibility provide further evidence for the superiority of ECPP. This work presents a promising strategy to enhance the efficacy of CHL in cancer therapy.

Shizukaol C alleviates trimethylamine oxide-induced inflammation through activating Keap1-Nrf2-GSTpi pathway in vascular smooth muscle cell.

BACKGROUND: Cardiovascular disease is one of the main causes of global mortality, and there is an urgent need for effective treatment strategies. Gut microbiota-dependent metabolite trimethylamine-N-oxide (TMAO) promotes the development of cardiovascular diseases, and shizukaol C, a natural sesquiterpene isolated from Chloranthus multistachys with various biological activities, might exhibit beneficial role in preventing TMAO-induced vascular inflammation. PURPOSE: The purpose of this study was to investigate the anti-inflammatory effects and the underlying mechanisms of shizukaol C on TMAO-induced vascular inflammation. METHODS: The effect and underlying mechanism of shizukaol C on TMAO-induced adhesion molecules expression, bone marrow-derived macrophages (BMDM) adhesion to VSMC were evaluated by western blot, cell adhesion assay, co-immunoprecipitation, immunofluorescence assay, and quantitative Real-Time PCR, respectively. To verify the role of shizukaol C in vivo, TMAO-induced vascular inflammation model were established using guidewire-induced injury on mice carotid artery. Changes in the intima area and the expression of GSTpi, VCAM-1, CD68 were examined using haematoxylin-eosin staining, and immunofluorescence assay. RESULTS: Our data demonstrated that shizukaol C significantly suppressed TMAO-induced adhesion molecule expression and the bone marrow-derived macrophages (BMDM) adhesion in vascular smooth muscle cells (VSMC). Mechanically, shizukaol C inhibited TMAO-induced c-Jun N-terminal kinase (JNK)-nuclear factor-kappa B (NF-κB)/p65 activation, and the JNK inhibition was dependent on the shizukaol C-mediated glutathione-S-transferase pi (GSTpi) expression. By further molecular docking and protein-binding analysis, we demonstrated that shizukaol C directly binds to Keap1 to induce Nrf2 nuclear translocation and upregulated GSTpi expression. Consistently, our in vivo experiment showed that shizukaol C elevated the expression level of GSTpi in carotid arteries and alleviates TMAO-induced vascular inflammation. CONCLUSION: Shizukaol C exerts anti-inflammatory effects in TMAO-treated VSMC by targeting Keap1 and activating Nrf2-GSTpi signaling and resultantly inhibits the downstream JNK-NF-κB/p65 activation and VSMC adhesion, and alleviates TMAO-induced vascular inflammation in vivo, suggesting that shizukaol C may be a potential drug for treating TMAO-induced vascular diseases.

Mechanisms of lipopolysaccharide protection in tumor drug-induced macrophage damage.

Malignant tumors contribute significantly to human mortality. Chemotherapy is a commonly used treatment for tumors. However, due to the low selectivity of chemotherapeutic drugs, immune cells can be damaged during antitumor treatment, resulting in toxicity. Lipopolysaccharide (LPS) can stimulate immune cells to respond to foreign substances. Here, we found that 10 ng/mL LPS could induce tolerance to antitumor drugs in macrophages without altering the effect of the drugs on tumor cells. Differentially expressed genes (DEGs) were identified between cells before and after LPS administration using transcriptome sequencing and found to be mainly associated with ATP-binding cassette (ABC)-resistant transporters and glutathione S-transferase (GST). LPS was shown by qRT-PCR and western blotting to promote the expression of ABCC1, GSTT1, and GSTP1 by 38.3 %, 194.8 %, and 27.0 %. Furthermore, three inhibitors (inhibitors of GST, glutathione synthesis, and ABCC1) were used for further investigation, showing that these inhibitors reduced macrophage survival rates by 44.0 %, 52.3 %, and 43.3 %, while the intracellular adriamycin content increased by 28.9 %, 42.9 %, and 51.3 %, respectively. These findings suggest that the protective mechanism of LPS on macrophages is associated with increased GST activity, the consumption of glutathione, and increased expression of ABCC1 protein. Therefore, LPS has a potential role in enhancing immunity.

PM2.5-induced DNA oxidative stress in A549 cells and regulating mechanisms by GST DNA methylation and Keap1/Nrf2 pathway.

Fine particulate matter (PM2.5) increases the risks of lung cancer. Epigenetics provides a new toxicology mechanism for the adverse health effects of PM2.5. However, the regulating mechanisms of PM2.5 exposure on candidate gene DNA methylation changes in the development of lung cancer remain unclear. Abnormal expression of the glutathione S transferase (GST) gene is associated with cancer. However, the relationship between PM2.5 and DNA methylation-mediated GST gene expression is not well understood. In this study, we performed GST DNA methylation analysis and GST-related gene expression in human A549 cells exposed to PM2.5 (0, 50, 100 µg/mL, from Taiyuan, China) for 24 h (n = 4). We found that PM2.5 may cause DNA oxidative damage to cells and the elevation of GSTP1 promotes cell resistance to reactive oxygen species (ROS). The Kelch-1ike ECH-associated protein l (Keap1)/nuclear factor NF-E2-related factor 2 (Nrf2) pathway activates the GSTP1. The decrease in the DNA methylation level of the GSTP1 gene enhances GSTP1 expression. GST DNA methylation is associated with reduced levels of 5-methylcytosine (5mC), DNA methyltransferase 1 (DNMT1), and histone deacetylases 3 (HDAC3). The GSTM1 was not sensitive to PM2.5 stimulation. Our findings suggest that PM2.5 activates GSTP1 to defend PM2.5-induced ROS and 8-hydroxy-deoxyguanosine (8-OHdG) formation through the Keap1/Nrf2 signaling pathway and GSTP1 DNA methylation.

Mechanistic insights into the inhibition of human placental glutathione S-transferase P1-1 by abscisic and gibberellic acids: An integrated experimental and computational study.

The interactions of the classic phytohormones gibberellic acid (gibberellin A3 , GA3 ) and abscisic acid (dormin, ABA), which antagonistically regulate several developmental processes and stress responses in higher plants, with human placental glutathione S-transferase P1-1 (hpGSTP1-1), an enzyme that plays a role in endo- or xenobiotic detoxification and regulation of cell survival and apoptosis, were investigated. The inhibitory potencies of ABA and GA3 against hpGSTP1, as well as the types of inhibition and the kinetic parameters, were determined by making use of both enzyme kinetic graphs and SPSS nonlinear regression models. The structural basis for the interaction between hpGSTP1-1 and phytohormones was predicted with the aid of molecular docking simulations. The IC50 values of ABA and GA3 were 5.3 and 5.0 mM, respectively. Both phytohormones inhibited hpGSTP1-1 in competitive manner with respect to the cosubstrates GSH and CDNB. When ABA was the inhibitor at [CDNB]f -[GSH]v and at [GSH]f -[CDNB]v , Vm , Km , and Ki values were statistically estimated to be 205 ± 16 µmol/min-mg protein, 1.32 ± 0.18 mM, 1.95 ± 0.25 mM and 175 ± 6 µmol/min-mg protein, 0.85 ± 0.06 mM, 1.85 ± 0.16 mM, respectively. On the other hand, the kinetic parameters Vm , Km , and Ki obtained with GA3 at [CDNB]f -[GSH]v and at [GSH]f -[CDNB]v were found to be 303 ± 14 µmol/min-mg protein, 1.77 ± 0.13 mM, 3.38 ± 0.26 mM and 249 ± 7 µmol/min-mg protein, 1.43 ± 0.07 mM, 2.89 ± 0.19 mM, respectively. Both phytohormones had the potential to engage in hydrogen-bonding and electrostatic interactions with the key residues that line the G- and H-sites of the enzyme's catalytic center. Inhibitory actions of ABA/GA3 on hpGSTP1-1 may guide medicinal chemists through the structure-based design of novel antineoplastic agents. It should be noted, however, that the same interactions may also render fetuses vulnerable to the potentially toxic effects of xenobiotics and noxious endobiotics.

A GSTP1-mediated lactic acid signaling promotes tumorigenesis through the PPP oxidative branch.

Lactic acidosis is a feature of solid tumors and plays fundamental role(s) rendering cancer cells to adapt to diverse metabolic stresses, but the mechanism underlying its roles in redox homeostasis remains elusive. Here we show that G6PD is phosphorylated at tyrosine 249/322 by the SRC through the formation of a GSTP1-G6PD-SRC complex. Lactic acid attenuates this formation and the phosphorylation of G6PD by non-covalently binding with GSTP1. Furthermore, lactic acid increases the activity of G6PD and facilitates the PPP (NADPH production) through its sensor GSTP1, thereby exhibiting resistance to reactive oxygen species when glucose is scarce. Abrogating a GSTP1-mediated lactic acid signaling showed attenuated tumor growth and reduced resistance to ROS in breast cancer cells. Importantly, positive correlations between immuno-enriched SRC protein and G6PD Y249/322 phosphorylation specifically manifest in ER/PR positive or HER negative types of breast cancer. Taken together, these results suggest that GSTP1 plays a key role in tumor development by functioning as a novel lactate sensor.

Progressive Spreading of DNA Methylation in the GSTP1 Promoter CpG Island across Transitions from Precursors to Invasive Prostate Cancer.

Glutathione S-transferase pi 1 (GSTP1) is lowly expressed in normal prostate luminal cells and becomes induced in most proliferative inflammatory atrophy (PIA) lesions. GSTP1 becomes silenced in prostatic intraepithelial neoplasia (PIN) and prostate adenocarcinoma (CaP) via cytosine-phospho-guanine (CpG) island promoter hypermethylation. However, GSTP1 methylation patterns in PIA and PIN, and their relationship to patterns in CaP are poorly understood. We used bisulfite genomic sequencing to examine patterns of GSTP1 promoter CpG island methylation in laser capture microdissected benign, PIA, PIN, and CaP regions from 32 subjects that underwent radical prostatectomy. We analyzed 908 sequence clones across 24 normal epithelium, 37 PIA, 18 PIN, and 23 CaP regions, allowing assessment of 34,863 CpG sites with allelic phasing. Normal and PIA lesions were mostly unmethylated with 0.52 and 1.3% of total CpG sites methylated, respectively. PIN and CaP lesions had greater methylation with 24% and 51% of total CpG sites methylated, respectively. The degree of GSTP1 methylation showed progression from PIA << PIN < CaP. PIN lesions showed more partial methylation compared with CaP lesions. Partially methylated lesions were enriched for methylation changes at AP1 and SP1 transcription factor binding sites. These results demonstrate that methylation density in the GSTP1 CpG island in PIN was intermediate relative to that in normal prostate epithelium/PIA and CaP lesions. These results are consistent with gradual spreading of DNA methylation centered at the SP1/AP1 transcription factor binding sites in precursor lesions, with subsequent spreading of methylation across the entire CpG island in transition to CaP. PREVENTION RELEVANCE: DNA hypermethylation at the GSTP1 promoter progressively spreads from being unmethylated in normal prostate to intermediate levels in precursor lesions to extensive methylation in cancer. This molecular progression of GSTP1 promoter methylation patterns in early prostate carcinogenesis could be useful for identification and interception of prostate cancer precursors.

Inhibition Analysis and High-Resolution Crystal Structure of Mus musculus Glutathione Transferase P1-1.

Multidrug resistance is a significant barrier that makes anticancer therapies less effective. Glutathione transferases (GSTs) are involved in multidrug resistance mechanisms and play a significant part in the metabolism of alkylating anticancer drugs. The purpose of this study was to screen and select a lead compound with high inhibitory potency against the isoenzyme GSTP1-1 from Mus musculus (MmGSTP1-1). The lead compound was selected following the screening of a library of currently approved and registered pesticides that belong to different chemical classes. The results showed that the fungicide iprodione [3-(3,5-dichlorophenyl)-2,4-dioxo-N-propan-2-ylimidazolidine-1-carboxamide] exhibited the highest inhibition potency (ΙC50 = 11.3 ± 0.5 µΜ) towards MmGSTP1-1. Kinetics analysis revealed that iprodione functions as a mixed-type inhibitor towards glutathione (GSH) and non-competitive inhibitor towards 1-chloro-2,4-dinitrobenzene (CDNB). X-ray crystallography was used to determine the crystal structure of MmGSTP1-1 at 1.28 Å resolution as a complex with S-(p-nitrobenzyl)glutathione (Nb-GSH). The crystal structure was used to map the ligand-binding site of MmGSTP1-1 and to provide structural data of the interaction of the enzyme with iprodione using molecular docking. The results of this study shed light on the inhibition mechanism of MmGSTP1-1 and provide a new compound as a potential lead structure for future drug/inhibitor development.

Ginsenoside Rg1 protects cardiac mitochondrial function via targeting GSTP1 to block S-glutathionylation of optic atrophy 1.

Mitochondrial dysfunction is a fundamental challenge in myocardial injury. Ginsenoside Rg1 (Rg1) is a bioactive compound with pharmacological potential for cardiac protection. Optic atrophy 1 (OPA1) acts as a mitochondrial inner membrane protein that contributes to the structural integrity and function of mitochondria. This study investigated the protective role of Rg1 in septic cardiac injury from the perspective of OPA1 stability. Rg1 protected cardiac contractive function against endotoxin injury in mice by maintaining mitochondrial cristae structure. In cardiomyocytes, lipopolysaccharide (LPS) evoked mitochondrial fragmentation and destruction of mitochondrial biogenesis, which were prevented by Rg1, possibly due to the preservation of the integrity of cristae structure. In support, the beneficial effects of Rg1 on cardioprotection and mitochondrial biogenesis were diminished by OPA1 deficiency subjected to the LPS challenge. Mechanistically, LPS stimulation triggered intracellular glutathione destabilization that promoted S-glutathionylation of OPA1 at Cys551, leading to the dissociation of OPA1-Mitofilin. Rg1 interacted with Glutathione S-transferase pi (GSTP1) to inhibit its mediated S-glutathionylation of OPA1, thereby promoting OPA1-Mitofilin interaction and protecting mitochondrial cristae structure. These findings suggest that GSTP1/OPA1 axis may be a beneficial strategy for the treatment of myocardial injury, and expand the clinical application of Rg1.

Age-related cataract: GSTP1 ubiquitination and degradation by Parkin inhibits its anti-apoptosis in lens epithelial cells.

PURPOSE: Oxidative stress-induced apoptosis of lens epithelial cells (LECs) contributes to the pathogenesis of age-related cataract (ARC). The purpose of this research is to underlie the potential mechanism of E3 ligase Parkin and its oxidative stress-associated substrate in cataractogenesis. METHODS: The central anterior capsules were obtained from patients with ARC, Emory mice, and corresponding controls. SRA01/04 cells were exposed to H2O2 combined with cycloheximide (a translational inhibitor), MG-132 (a proteasome inhibitor), chloroquine (an autophagy inhibitor), Mdivi-1 (a mitochondrial division inhibitor), respectively. Co-immunoprecipitation was employed to detect protein-protein interactions and ubiquitin-tagged protein products. Levels of proteins and mRNA were evaluated by western blotting and quantitative RT-PCR assays. RESULTS: Glutathione-S-transferase P1 (GSTP1) was identified as a novel Parkin substrate. Compared with corresponding controls, GSTP1 was significantly decreased in the anterior lens capsules obtained from human cataracts and Emory mice. Similarly, GSTP1 was declined in H2O2-stimulated SRA01/04 cells. Ectopic expression of GSTP1 mitigated H2O2-induced apoptosis, whereas silencing GSTP1 aggregated apoptosis. In addition, H2O2 stimulation and Parkin overexpression could promote the degradation of GSTP1 through the ubiquitin-proteasome system, autophagy-lysosome pathway, and mitophagy. After co-transfection with Parkin, the non-ubiquitinatable GSTP1 mutant maintained its anti-apoptotic function, while wildtype GSTP1 failed. Mechanistically, GSTP1 might promote mitochondrial fusion through upregulating Mitofusins 1/2 (MFN1/2). CONCLUSION: Oxidative stress induces LECs apoptosis via Parkin-regulated degradation of GSTP1, which may provide potential targets for ARC therapy.

Targeting GSTP1 as Therapeutic Strategy against Lung Adenocarcinoma Stemness and Resistance to Tyrosine Kinase Inhibitors.

Glutathione S-transferase pi (GSTP1), a phase II detoxification enzyme, is known to be overexpressed and mediates chemotherapeutic resistance in lung cancer. However, whether GSTP1 supports cancer stem cells (CSCs) and the underlying mechanisms in lung adenocarcinoma (LUAD) remain largely unknown. This study unveiled that GSTP1 is upregulated in lung CSCs and supports tumor self-renewal, metastasis, and resistance to targeted tyrosine kinase inhibitors of LUAD both in vitro and in vivo. Mechanistically, CaMK2A (calcium/calmodulin-dependent protein kinase 2 isoform A)/NRF2 (nuclear factor erythroid 2-related factor 2)/GSTP1 is uncovered as a regulatory axis under hypoxia. CaMK2A increased GSTP1 expression through phosphorylating the Sersine558 residue of NRF2 and promoting its nuclear translocation, a novel mechanism for NRF2 activation apart from conventional oxidization-dependent activation. Upregulation of GSTP1 in turn suppressed reactive oxygen species levels and supported CSC phenotypes. Clinically, GSTP1 analyzed by immunohistochemistry is upregulated in a proportion of LUAD and serves as a prognostic marker for survival. Using patient-derived organoids from an ALK-translocated LUAD, the therapeutic potential of a specific GSTP1 inhibitor ezatiostat in combination treatment with the ALK inhibitor crizotinib is demonstrated. This study demonstrates GSTP1 to be a promising therapeutic target for long-term control of LUAD through targeting CSCs.

The good Samaritan glutathione-S-transferase P1: An evolving relationship in nitric oxide metabolism mediated by the direct interactions between multiple effector molecules.

Glutathione-S-transferases (GSTs) are phase II detoxification isozymes that conjugate glutathione (GSH) to xenobiotics and also suppress redox stress. It was suggested that GSTs have evolved not to enhance their GSH affinity, but to better interact with and metabolize cytotoxic nitric oxide (NO). The interactions between NO and GSTs involve their ability to bind and store NO as dinitrosyl-dithiol iron complexes (DNICs) within cells. Additionally, the association of GSTP1 with inducible nitric oxide synthase (iNOS) results in its inhibition. The function of NO in vasodilation together with studies associating GSTM1 or GSTT1 null genotypes with preeclampsia, additionally suggests an intriguing connection between NO and GSTs. Furthermore, suppression of c-Jun N-terminal kinase (JNK) activity occurs upon increased levels of GSTP1 or NO that decreases transcription of JNK target genes such as c-Jun and c-Fos, which inhibit apoptosis. This latter effect is mediated by the direct association of GSTs with MAPK proteins. GSTP1 can also inhibit nuclear factor kappa B (NF-κB) signaling through its interactions with IKKß and Iκα, resulting in decreased iNOS expression and the stimulation of apoptosis. It can be suggested that the inhibitory activity of GSTP1 within the JNK and NF-κB pathways may be involved in crosstalk between survival and apoptosis pathways and modulating NO-mediated ROS generation. These studies highlight an innovative role of GSTs in NO metabolism through their interaction with multiple effector proteins, with GSTP1 functioning as a "good Samaritan" within each pathway to promote favorable cellular conditions and NO levels.

Praeruptorin B inhibits osteoclastogenesis by targeting GSTP1 and impacting on the S-glutathionylation of IKKß.

Osteoporosis a common disease in postmenopausal women which contains significant impact on the living quality of women. With the aging of the population, the number of patients suffer from osteoporosis has shown a significant increase. Given the limitations of clinical drugs for the treatment of osteoporosis, natural extracts with small side effects have a great application prospect in the treatment of osteoporosis. Praeruptorin B (Pra-B), is one of the main components found in the roots of Peucedanum praeruptorum Dunn and exhibits anti-inflammatory effects. However, there is no research on the influence of Pra-B on osteoporosis. Here, we showed that Pra-B can dose-dependently suppress osteoclastogenesis without cytotoxicity. Receptor activator of nuclear factor kappa-B (NF-κB) ligand (RANKL)-induced the nuclear import of P65 was inhibited by Pra-B, which indicated the suppressive effect of Pra-B on NF-κB signaling. Further, Pra-B enhanced the expression of Glutathione S-transferase Pi 1 (GSTP1) and promoted the S-glutathionylation of IKKß to inhibit the nuclear translocation of P65. Moreover, in vivo experiments showed that Pra-B considerably attenuated the bone loss in ovariectomy (OVX)-induced mice. Collectively, our studies revealed that Pra-B suppress the NF-κB signaling targeting GSTP1 to rescued RANKL-induced osteoclastogenesis in vitro and OVX-induced bone loss in vivo, supporting the potential of Pra-B for treating osteoporosis in the future.

Implications of glutathione-S transferase P1 in MAPK signaling as a CRAF chaperone: In memory of Dr. Irving Listowsky.

Glutathione-S transferase P1 (GSTP1) is one of the glutathione-S transferase isozymes that belong to a family of phase II metabolic isozymes. The unique feature of GSTP1 compared with other GST isozymes is its relatively high expression in malignant tissues. Thus, clinically, GSTP1 serves as a tumor marker and as a refractory factor against certain types of anticancer drugs through its primary function as a detoxifying enzyme. Additionally, recent studies have identified a chaperone activity of GSTP1 involved in the regulation the function of various intracellular proteins, including factors of the growth signaling pathway. In this review, we will first describe the function of GSTP1 and then extend the details onto its role in the mitogen-activated protein kinase signal pathway, referring to the results of our recent study that proposed a novel autocrine signal loop formed by the CRAF/GSTP1 complex in mutated KRAS and BRAF cancers. Finally, the possibilities of new therapeutic approaches for these cancers by targeting this complex will be discussed.

Influence of GSTP1 rs1695 polymorphism on survival in male patients' amyotrophic lateral sclerosis: a genetic association study in Brazilian population.

BACKGROUND: Glutathione S-transferase Pi (GSTP1) enzyme has a major antioxidant effect on the central nervous system (CNS), where it acts against oxidative damage, an established risk factor for amyotrophic lateral sclerosis (ALS). Hence, the purpose of this study was to evaluate a possible relationship between GSTP1 rs1695 polymorphism and the survival rate of male ALS patients, which is the gender more affected by the disease. METHODS AND RESULTS: A case-control study was performed with 56 male ALS patients and 70 healthy male individuals from Midwestern Brazil, which were age-adjusted. GSTP1 rs1695 polymorphism molecular analysis was carried out with restriction fragment length polymorphism. The relationship between ALS patients and GSTP1 rs1695 polymorphism was analyzed using cumulative survival rate as the major outcome, where differences in survival were evaluated through the log-rank test. Our results revealed that mutant genotype (G/G) did not influence the cumulative survival rate of male ALS patients regarding the age of diagnosis (p = 0.5) and time from symptom to diagnosis (p = 0.3). On the other hand, mutant carriers exhibited a significant survival of fewer than 25 months compared to A/A and A/G genotypes that survive more than 100 months (p = 7-E10) in comparison with symptom onset to outcome (p = 0.00006). CONCLUSIONS: In summary, our findings revealed that mutant genotype carriers' male patients had a reduced lifetime, which probably may be resulted from oxidative stress exposure in CNS.

Tissue expression of glutathione S transferase isoenzymes in vitiligo.

The association of glutathione S-transferase (GST) enzymes with vitiligo is inconclusive. To evaluate tissue expressions of GST isoenzymes in vitiligo patients and to compare these expressions with healthy controls, we used 26 active depigmented patches on the trunk of vitiligo patients and 20 healthy sex and age matched controls. Punch biopsies were taken from the lesioned or normal skin. Tissue expression of GST isoenzymes were analyzed immunohistochemically. Tissue expression of GSTT1, GSTA1 and GSTP1 was significantly higher in the patient group than controls. Tissue expression of GSTM1 was not significantly different between the two groups. The increased tissue expression of GSTT1, GSTA1 and GSTP1 may represent a response to excess free radical formation in vitiligo and may support the role of oxidative stress in the pathogenesis of vitiligo.

ROLE OF GENETIC PREDISPOSITION, GENE POLYMORPHISM OF GLUTATHIONE-S-TRANSFERASE (GSTT1, GSTM1, GSTP1) AND SOME ADVERSE FACTORS IN DEVELOPMENT OF BRONCHIAL ASTHMA IN CHILDREN - RESIDENTS OF RADIOACTIVELY CONTAMINATED AREAS. / ROL' SPADKOVOÏ SKhYL'NOSTI, POLIMORFIZMU GENIV GLUTATION/S/TRANSFERAZ (GSTT1, GSTM1, GSTP1) TA DEIaKYKh NESPRYIaTLYVYKh ChYNNYKIV U ROZVYTKU BRONKhIAL'NOÏ ASTMY U DITEI ­ MEShKANTsIV RADIOAKTYVNO ZABRUDNENYKh TERYTORII.

OBJECTIVE: to determine the influence of hereditary predisposition, polymorphism of GSTT1, GSTM1, GSTP1 genes andenvironmental factors on the development of bronchial asthma in children - residents of radioactively contaminat-ed areas. MATERIALS AND METHODS: School-age children-residents of radioactively contaminated areas with bronchial asthma,and those without clinical signs of respiratory pathology were examined. Genetic, medical, biological and social riskfactors were determined based on the study of anamnestic data and medical records. Ventilation lung capacity wasassessed by the method of computer spirometry. Molecular genetic studies were carried out using polymerase chainreaction (PCR) and restriction fragment length polymorphism (RFLP) for further analysis. RESULTS: Molecular genetic studies of the distribution of genotypes and frequencies of polymorphic variants of thegenes GSTT1, GSTM1, GSTP1 were performed in children living under long-term intake of 137Cs by food chains. It wasfound that in children with BA the tendency to frequency of the deletion variant of the GSTT1 and GSTM1 genes incomparison with children without bronchial and pulmonary pathology was increased. The study of distributing theGSTP1 A313G gene polymorphic variants revealed in children with BA a significant increase in the frequency of AG-genotype, compared with the data of reference group. Adverse factors that increase the risk of developing bron-choobstructive disorders and the probability of their implementation in the form of bronchial asthma in children -residents of RCA have been identified. It is established that among them the leading role is played by hereditarypredisposition to this disease. On the part of the child, such negative factors were unfavorable conditions of fetaldevelopment, the presence of signs of exudative-catarrhal diathesis, manifestations of allergies and frequent respi-ratory diseases from the first months of life. It was found that the risk of developing BA was significantly increasedin children with the GSTT1 and GSTM1 gene deletion genotypes; an increased risk of developing BA in children witha combination of the GSTP1 A313G gene polymorphism with deletion polymorphism of the GSTT1 or GSTM1 gene wasdetermined. Сonclusion. Оne of the leading mechanisms, due to which there is a realization of hereditary predisposition tobronchial asthma in children living under constant intake of radionuclides with a long half-life, is the polymorphismof certain glutathione-S-transferase genes, namely, GSTT1, GSTM1 and A313G gene deletion polymorphism and GSTP1gene polymorphism.

Oxidative Stress Induced Cell Cycle Arrest: Potential Role of PRX-2 and GSTP-1 as Therapeutic Targets in Hepatocellular Carcinoma.

BACKGROUND: The increasing incidence and mortality rate of HCC is a major concern, especially for developing countries of the world. Hence, extensive research is being carried out in order to explore new approaches for developing successful therapeutic strategies for HCC. The controversial role of oxidative stress in the prognosis and treatment of various diseases such as cancer has become an area of great interest and intrigue for many scientists throughout the world. OBJECTIVE: We aim to investigate the role of induced oxidative stress on the suppression of HCC Huh-7 cancerous cells as a therapeutic approach. METHODS: Induction of oxidative stress via H2O2 treatment produced cell cytotoxicity in a dose dependent manner and also led to the overexpression of GSTP-1 and PRX-2. The expression of GSTP- 1 and PRX-2 was compared in HCC Huh-7 treated, untreated cells and normal hepatocytes using immunocytochemistry. Furthermore, the effects of oxidative stress on cell cycle arrest were also studied through flow cytometry. RESULTS: Our study demonstrated the inhibition of cancer cell proliferation as a result of H2O2 induction by arresting the cell cycle at the G2 phase. CONCLUSION: The induction of oxidative stress could be a potential therapeutic approach for treating HCC in the future. GSTP-1 and PRX-2 can serve as substantial therapeutic targets for the treatment of HCC.

GSTP1 Ile105Val polymorphism among North Indian lung cancer patients treated using monotherapy and poly-pharmacy.

BACKGROUND: Genetic polymorphism within the P1 isoenzyme of the Glutathione-S-Transferase (GST) family is found to modulate and alter the enzyme activity of GSTP1 protein and thus may result in a change of sensitivity to platinum-based chemotherapy. We investigated the relationship between GSTP1 Ile105Val polymorphisms and overall survival, treatment response, and for both hematological and non-hematological toxicity of advanced North Indian lung cancer patients undergoing platinum-based double chemotherapy. METHODS: The polymorphism of GSTP1 Ile105Val in North Indian lung cancer patients was assessed by polymerase chain reaction-restriction fragment length polymorphism. A total of 682 lung cancer patients were enrolled in the study, and it was observed that patients who were carrying both the mutant alleles (Val/Val) for the GSTP1 polymorphism showed a higher trend of median survival time (MST) as compared to the patients bearing the wild type of genotype (Ile/Ile) (MST = 8.30 vs. 7.47, p = 0.56). Based on toxicity profiling, we observed that lung cancer patients with the mutant genotype of GSTP1 (Val/Val) had an increased risk of leukopenia (OR = 2.41; 95% CI = 1.39-4.18, p = 0.001) as compared to subjects carrying both copies of the wild alleles (Ile/Ile). Our data suggested that patients with heterozygous genotype (Ile/Val) had a 2.14-fold increased risk of developing severe anemia (OR = 2.14, 95% CI = 0.97-4.62, p = 0.03). Our data also showed that in small cell lung carcinoma (SCLC) patients' polymorphism of GSTP1 was associated with thrombocytopenia (χ2 test = 7.32, p = 0.02). CONCLUSIONS: Our results suggest that GSTP1 Ile105Val polymorphism could be a predictive biomarker for hematological toxicity, like leukopenia and anemia, but not thrombocytopenia or neutropenia.

Potential Role of GST-π in Lung Cancer Stem Cell Cisplatin Resistance.

BACKGROUND: Cancer stem cells (CSCs) are responsible for tumorigenesis, chemoresistance, and metastasis. Chemoresistance is a major challenge in the management of lung cancer. Glutathione-sulphur-transferase-π (GST-π) plays an important role in the origin and development of various types of cancer by regulating the cellular redox balance. Recent investigations have demonstrated that GST-π is associated with the chemoresistance of lung CSCs (LCSCs). However, the mechanism of GST-π in lung cancer, particularly in LCSCs, remains unclear. The present study is aimed at exploring the potential role of GST-π in stemness and cisplatin (DDP) resistance of LCSCs. Materials and methods. In the present study, lung cancer cell spheres were established using the A549 cell line, which according to our previous research, was confirmed to exhibit characteristics of stem cells. Next, GST-π protein expression, apoptosis percentage, and intracellular reactive oxygen species (ROS) concentration in A549 adherent cells and A549 cell spheres were analyzed by western blotting and flow cytometry, respectively. Finally, DDP resistance, ROS concentration, and GST-π expression in LCSCs were analyzed following the interference with GST-π using DL-buthionine-(S,R)-sulphoximine and N-acetylcysteine. RESULTS: The results revealed that GST-π was highly expressed in A549 cell spheres compared with A549 adherent cells and was associated with a decreased intracellular ROS concentration (both P < 0.05). Regulating GST-π protein expression could alter DDP resistance of LCSCs by influencing ROS. CONCLUSION: These results suggested that GST-π may be important for LCSC drug resistance by downregulating ROS levels. These findings may contribute to the development of new adjuvant therapeutic strategies for lung cancer.