Multidrug resistance (MDR) mechanisms in cancer cells are greatly influenced by glutathione transferase P1-1 (hGSTP1-1). The use of synthetic or natural compounds as hGSTP1-1 inhibitors is considered an effective approach to overcome MDR. Nine compounds consisting of coumarin-6-sulfonamide linked to chalcone derivatives were synthesized and evaluated for their ability to inhibit hGSTP1-1. Among the synthetic derivatives, compounds 5g, 5f, and 5a displayed the most potent inhibitory effect, with IC50 values of 12.2 ± 0.5 μΜ, 12.7 ± 0.7 and 16.3 ± 0.6, respectively. Kinetic inhibition analysis of the most potent molecule, 5g, showed that it behaves as a mixed-type inhibitor of the target enzyme. An in vitro cytotoxicity assessment of 5a, 5f, and 5g against the human prostate cancer cell lines DU-145 and PC3, as well as the breast cancer cell line MCF-7, demonstrated that compound 5g exhibited the most pronounced cytotoxic effect on all tested cell lines. Molecular docking studies were performed to predict the structural and molecular determinants of 5g, 5f, and 5a binding to hGSTP1-1. In agreement with the experimental data, the results revealed that 5g exhibited the lowest docking score among the three studied inhibitors as a consequence of shape complementarity, governed by van der Waals, hydrogen bonds and a π-π stacking interaction. These findings suggest that coumarin-chalcone hybrids offer new perspectives for the development of safe and efficient natural product-based sensitizers that can target hGSTP1-1 for anticancer purposes.

Glucocorticoids (GCs) are known to stimulate pancreatic beta (β)-cell apoptosis via several mechanisms, including oxidative stress. Our previous study suggested an increase in dexamethasone-induced pancreatic β-cell apoptosis via a reduction of glutathione S-transferase P1 (GSTP1), which is an antioxidant enzyme. Imatinib, which is a tyrosine kinase inhibitor, also exerts antioxidant effect. This study aims to test our hypothesis that imatinib would prevent pancreatic β-cell apoptosis induced by dexamethasone via increased GSTP1 expression and reduced oxidative stress. Our results revealed that dexamethasone significantly increased apoptosis in INS-1 cells when compared to the control, and that imatinib significantly decreased INS-1 cell apoptosis induced by dexamethasone. Moreover, dexamethasone significantly increased superoxide production in INS-1 cells when compared to the control; however, imatinib, when combined with dexamethasone, significantly reduced superoxide production in INS-1 cells. Dexamethasone significantly decreased GSTP1, p-ERK1/2, and BCL2 protein expression, but significantly increased p-JNK, p-p38, and BAX protein expression in INS-1 cells-all compared to control. Importantly, imatinib significantly ameliorated the effect of dexamethasone on the expression of GSTP1, p-ERK1/2, p-JNK, p-p38 MAPK, BAX, and BCL2. Furthermore-6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio) hexanol (NBDHEX), which is a GSTP1 inhibitor, neutralized the protective effect of imatinib against pancreatic β-cell apoptosis induced by dexamethasone. In conclusion, imatinib decreases pancreatic β-cell apoptosis induced by dexamethasone via increased GSTP1 expression and reduced oxidative stress.

BACKGROUND: Glutathione S-Transferase (GST) is a family of phase II metabolizing enzymes contribute to detoxification and elimination of variety of endogenous as well as exogenous xenobiotics including chemotherapeutic agents. The comprehensive knowledge on the impact of genetic polymorphisms in GST) enzyme coding gene will help to understand the clinical outcomes in breast cancer patients treated with either Adriamycin or paclitaxel or combination of both. In this study we attempted to assess the genetic polymorphisms in GSTM1, GSTT1, GSTP1 and their association with Adriamycin and Paclitaxel induced toxicity reactions in breast cancer patients.
METHODS: Two hundred BC patients receiving Adriamycin and Paclitaxel chemotherapy were enrolled in this study and chemotherapy induced hematological and non-hematological toxicity reactions were noted. The polymorphisms in GSTM1, GSTP1 and GSTT1 gene were studied by PCR and RFLP analysis.
RESULTS: After the univariate analysis of the genetic polymorphisms of GSTM1, GSTP1 and GSTT1 showed that GSTT1 null genotype showed significant association with neutropenia (OR=2.84, 95% CI: 1.06-7.56; p=0.036) in breast cancer patients treated with Adriamycin and GSTT1 null genotype in patients with >1 CINV toxicity confirmed significant correlation (OR=3.75, 95% CI: 1.46-9.59; p=0.005). The genetic polymorphisms of GSTP1 (exon 5) A/G heterozygous genotype was significant in grade >1 toxicity reactions of mucositis (OR=3.22, 95% CI: 1.06-9.71; p=0.037) in breast cancer patients administered with Paclitaxel chemotherapy.
CONCLUSIONS: The findings obtained from this study proposed significant involvement of GSTT1-null genotype in hematological neutropenia toxicity in response to Adriamycin and GSTM1-null genotype showed negative association with non-hematological toxicity (bodyache) in response to Paclitaxel.

Endothelial cell injury is a hallmark of IgA vasculitis (IgAV), possibly associated with various factors, including oxidative stress. Certain single nucleotide polymorphisms (SNPs) of glutathione S-transferases (GST) genes have been shown to increase susceptibility to oxidative stress. The objective of our study was to evaluate the gene polymorphisms of GSTM1, GSTT1, GSTP1, and GSTA1 in patients with IgAV. DNA was extracted from the blood of 124 children with IgAV and 168 age-matched healthy controls. A higher frequency of the GSTM1 null genotype was observed in patients with gastrointestinal (GI) system involvement compared to those without GI system involvement (51.5% vs. 28.6%, p = 0.011). Additionally, the GSTM1 null genotype was less prevalent (30.8% vs. 69.2%, p = 0.032), while the GSTP1 Val/Val genotype was significantly more prevalent in patients who developed urogenital complications (scrotal swelling) during the course of the disease (60% vs. 40%, p = 0.039). This study is the first to suggest an association between GSTM1 and GSTP1 polymorphisms and various phenotypes observed during the clinical course of IgAV in the pediatric population. However, it was performed on a national and likely single ethnic cohort, too small for definitive conclusions, so larger studies are needed to confirm this association.

Hypertension is a leading risk factor for disease burden worldwide. Vascular contraction and remodeling contribute to the development of hypertension. Glutathione S-transferase P1 (Gstp1) plays several critical roles in both normal and neoplastic cells. In this study, we investigated the effect of Gstp1 on hypertension as well as on vascular smooth muscle cell (VSMC) contraction and phenotypic switching. We identified the higher level of Gstp1 in arteries and VSMCs from hypertensive rats compared with normotensive rats for the first time. We then developed Adeno-associated virus 9 (AAV9) mediated Gstp1 down-regulation and overexpression in rats and measured rat blood pressure by using the tail-cuff and the carotid catheter method. We found that the blood pressure of spontaneously hypertensive rats (SHR) rose significantly with Gstp1 down-regulation and reduced apparently after Gstp1 overexpression. Similar results were obtained from the observations of 2-kidney-1-clip renovascular (2K1C) hypertensive rats. Gstp1 did not influence blood pressure of normotensive Wistar-Kyoto (WKY) rats and Sprague-Dawley (SD) rats. Further in vitro study indicated that Gstp1 knockdown in SHR-VSMCs promoted cell proliferation, migration, dedifferentiation and contraction, while Gstp1 overexpression showed opposite effects. Results from bioinformatic analysis showed that the Apelin/APLNR system was involved in the effect of Gstp1 on SHR-VSMCs. The rise in blood pressure of SHR induced by Gstp1 knockdown could be reversed by APLNR antagonist F13A. We further found that Gstp1 enhanced the association between APLNR and Nedd4 E3 ubiquitin ligases to induce APLNR ubiquitination degradation. Thus, in the present study, we discovered a novel anti-hypertensive role of Gstp1 in hypertensive rats and provided the experimental basis for designing an effective anti-hypertensive therapeutic strategy.

The allele and genotype frequencies of the polymorphic loci CYP1A1 (rs1048943), GSTP1 (rs1695 and rs1138272), GSTM1, and GSTT1 genes were studied in 517 men: in 389 accumulated mercury pollution liquidators (207 firefighters of the Ministry of the Russian Federation for Civil Defence, Emergencies and Elimination of Consequences of Natural Disasters and 182 employees of the Federal Environmental Operator) and 128 former workers (82 patients in the delayed period of chronic mercury intoxication and 46 individuals contacted with mercury and had no chronic mercury intoxication). We found differences in the frequencies of AA and AG genotypes in groups of former workers (χ2=6.96, p=0.008) for the polymorphic locus rs1048943, while the AG-CYP1A1 genotype was characterized by a 5.5-fold decrease in the odds ratio for the development of chronic mercury intoxication (OR=0.18, p=0.0041). An unfavorable combination of genotypes of the studied polymorphic loci increases the risk of undesirable health effects.

The oncogene and drug metabolism enzyme glutathione S-transferase P (GSTP) is also a GSH-dependent chaperone of signal transduction and transcriptional proteins with key role in liver carcinogenesis. In this study, we explored this role of GSTP in hepatocellular carcinoma (HCC) investigating the possible interaction of this protein with one of its transcription factor and metronome of the cancer cell redox, namely the nuclear factor erythroid 2-related factor 2 (Nrf2). Expression, cellular distribution, and function as glutathionylation factor of GSTP1-1 isoform were investigated in the mouse model of N-nitrosodiethylamine (DEN)-induced HCC and in vitro in human HCC cell lines. The physical and functional interaction of GSTP protein with Nrf2 and Keap1 were investigated by immunoprecipitation and gene manipulation experiments. GSTP protein increased its liver expression, enzymatic activity and nuclear levels during DEN-induced tumor development in mice; protein glutathionylation (PSSG) was increased in the tumor masses. Higher levels and a preferential nuclear localization of GSTP protein were also observed in HepG2 and Huh-7 hepatocarcinoma cells compared to HepaRG non-cancerous cells, along with increased basal and Ebselen-stimulated levels of free GSH and PSSG. GSTP activity inhibition with the GSH analogue EZT induced apoptotic cell death in HCC cells. Hepatic Nrf2 and c-Jun, two transcription factors involved in GSTP expression and GSH biosynthesis, were induced in DEN-HCC compared to control animals; the Nrf2 inhibitory proteins Keap1 and β-TrCP also increased and oligomeric forms of GSTP co-immunoprecipitated with both Nrf2 and Keap1. Nrf2 nuclear translocation and β-TrCP expression also increased in HCC cells, and GSTP transfection in HepaRG cells induced Nrf2 activation. In conclusion, GSTP expression and subcellular distribution are modified in HCC cells and apparently contribute to the GSH-dependent reprogramming of the cellular redox in this type of cancer directly influencing the transcriptional system Nrf2/Keap1.

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.

Background and Objectives: Despite improvements in screening programs, a large number of patients with colorectal cancer (CRC) are diagnosed in an advanced disease stage. Previous investigations imply that glutathione transferases (GSTs) might be associated with the development and progression of CRC. Moreover, the detoxification mechanism of oxaliplatin, which represents the first line of treatment for advanced CRC, is mediated via certain GSTs. The aim of this study was to evaluate the significance of certain GST genetic variants on CRC prognosis and the efficacy of oxaliplatin-based treatment. Materials and Methods: This prospective study included 523 patients diagnosed with CRC in the period between 2014 and 2016, at the Digestive Surgery Clinic, University Clinical Center of Serbia, Belgrade. Patients were followed for a median of 43.47 ± 17.01 months (minimum 1-63 months). Additionally, 109 patients with advanced disease, after surgical treatment, received FOLFOX6 treatment as a first-line therapy between 2014 and 2020. The Kaplan-Meier method was used to analyze cumulative survival, and the Cox proportional hazard regression model was used to study the effects of different GST genotypes on overall survival. Results: Individuals with the GSTM1-null genotype and the GSTP1 IleVal+ValVal (variant) genotype had significantly shorter survival when compared to referent genotypes (GSTM1-active and GSTP1 IleIle) (log-rank: p = 0.001). Moreover, individuals with the GSTM1-null genotype who received 5-FU-based treatment had statistically significantly shorter survival when compared to individuals with the GSTM1-active genotype (log-rank: p = 0.05). Conclusions: Both GSTM1-null and GSTP1 IleVal+ValVal (variant) genotypes are associated with significantly shorter survival in CRC patients. What is more, the GSTM1-null genotype is associated with shorter survival in patients receiving FOLOFOX6 treatment.

In the department of Boyacá, Colombia, agriculture stands as one of the primary economic activities. However, the escalating utilization of pesticides within this sector has sparked concern regarding its potential correlation with elevated risks of genotoxicity, chromosomal alterations, and carcinogenesis. Furthermore, pesticides have been associated with a broad spectrum of genetic polymorphisms that impact pivotal genes involved in pesticide metabolism and DNA repair, among other processes. Nonetheless, our understanding of the genotoxic effects of pesticides on the chromosomes (as biomarkers of effect) in exposed farmers and the impact of genetic polymorphisms (as susceptibility biomarkers) on the increased risk of chromosomal damage is still limited. The aim of our study was to evaluate chromosomal alterations, chromosomal instability, and clonal heterogeneity, as well as the presence of polymorphic variants in the GSTP1 and XRCC1 genes, in peripheral blood samples of farmers occupationally exposed to pesticides in Aquitania, Colombia, and in an unexposed control group. Our results showed statistically significant differences in the frequency of numerical chromosomal alterations, chromosomal instability, and clonal heterogeneity levels between the exposed and unexposed groups. In addition, we also found a higher frequency of chromosomal instability and clonal heterogeneity in exposed individuals carrying the heterozygous GSTP1 AG and XRCC1 (exon 10) GA genotypes. The evaluation of chromosomal alterations and chromosomal instability resulting from pesticide exposure, combined with the identification of polymorphic variants in the GSTP1 and XRCC1 genes, and further research involving a larger group of individuals exposed to pesticides could enable the identification of effect and susceptibility biomarkers. Such markers could prove valuable for monitoring individuals occupationally exposed to pesticides.