Drug resistance gene expression and chemotherapy sensitivity detection in Chinese women with different molecular subtypes of breast cancer.

Objective: The aim of the study was to identify specific chemosensitivity drugs for various molecular subtypes of breast tumors in Chinese women, by detecting the expression of drug resistance genes and by using the drug sensitivity test on different molecular subtypes of breast cancers. Methods: The expression of drug resistance genes including Topo II, GST-π, P-gp, LRP, and CD133 were detected with immunohistochemistry in a tissue microarray. Drug sensitivity tests included those for paclitaxel, epirubicin, carboplatin, vinorelbine, and fluorouracil and were conducted on primary cancer tissue cells and cell lines, including the T47D, BT-474, and MDA-MB-231 cells and human breast cancer xenografts in nude mice. Results: The different drug resistant genes Topo II, GST-π, P-gp, and LRP were differentially expressed among different molecular subtypes of breast cancers (P < 0.05). Positive expression of CD133 was highest in basal-like breast cancer (P < 0.05). Kaplan-Meier survival analysis showed that positive expressions of Topo II and CD133 both correlated with shorter disease-free survival (DFS) (P < 0.05) and overall survival (P < 0.05), and positive expression of LRP correlated only with shorter DFS (P < 0.05). BT-474 showed chemosensitivity to paclitaxel and epirubicin, while MDA-MB-231 showed chemosensitivities to paclitaxel, epirubicin, carboplatin, and fluorouracil (T/C ≤ 50%). The basal-like and HER2+ breast cancer primary cells showed chemosensitivities to paclitaxel and epirubicin with significant differences compared with luminal breast cancer primary cells (P < 0.05). Conclusions: The differential expression of drug resistance genes and the differential chemosensitivities of drugs in different molecular subtype of breast cancers suggested that individual treatment should be given for each type of breast cancer.

GSTP1 rs1138272 Polymorphism Affects Prostate Cancer Risk.

Background and Objectives: One of the most frequent genetic alterations reported to date in prostate cancer (PC) is aberrant methylation of glutathione transferase P1 (GSTP1). Taking into consideration the involvement of oxidative stress in PC pathogenesis and recent advances in scientific understanding of the role of GSTP1*Ala114Val rs1138272 polymorphism in carcinogenesis, we hypothesized that this single-nucleotide polymorphism (SNP) influences the risk of PC independently of, or in combination with, other GST polymorphisms, including GSTP1*IIe105Val rs1695 or GSTM1 and GSTT1 deletion polymorphisms. Materials and Methods: Genotyping was performed in 237 PC cases and in 236 age-matched controls by multiplex polymerase chain reaction (PCR) for deletion of GST polymorphisms and by quantitative PCR for SNPs. Results: We found that carriers of either GSTP1*Val (rs1138272) or GSTP1*Val (rs1695) variant alleles had a PC risk compared to individuals with both referent alleles (OR = 4.93, 95%CI: 2.89-8.40, p < 0.001 and OR = 1.8, 95%CI: 1.19-2.73, p = 0.006, respectively). Additionally, in a haplotype analysis we found that individuals with GSTP1*C haplotype, represented by both variant alleles (GSTP1*Val rs1695 + GSTP1*Val rs1138272), had a 5.46 times higher risk of PC development compared to individuals with the most frequent haplotype (95%CI = 2.56-11.65, p < 0.001), suggesting a potential role of those variants in PC susceptibility. A regression analysis on the number of risk-associated alleles per individual (GSTM1*active, GSTT1*null, GSTP1*Val rs1695 and GSTP1*Val rs1138272) showed a significant increase in the risk of developing PC, from 3.65-fold in carriers of two risk alleles (95%CI = 1.55-8.61, p = 0.003) to an approximately 12-fold increase in carriers of all four risk alleles (95%CI = 3.05-44.93, p < 0.001). Conclusion: Prostate cancer may be influenced by multiple glutathione transferase (GST) polymorphic genes, especially GSTP1, highlighting the role of gene-gene interactions in human susceptibility to this cancer.

A three-gene DNA methylation biomarker accurately classifies early stage prostate cancer.

BACKGROUND: We identify and validate accurate diagnostic biomarkers for prostate cancer through a systematic evaluation of DNA methylation alterations. MATERIALS AND METHODS: We assembled three early prostate cancer cohorts (total patients = 699) from which we collected and processed over 1300 prostatectomy tissue samples for DNA extraction. Using real-time methylation-specific PCR, we measured normalized methylation levels at 15 frequently methylated loci. After partitioning sample sets into independent training and validation cohorts, classifiers were developed using logistic regression, analyzed, and validated. RESULTS: In the training dataset, DNA methylation levels at 7 of 15 genomic loci (glutathione S-transferase Pi 1 [GSTP1], CCDC181, hyaluronan, and proteoglycan link protein 3 [HAPLN3], GSTM2, growth arrest-specific 6 [GAS6], RASSF1, and APC) showed large differences between cancer and benign samples. The best binary classifier was the GAS6/GSTP1/HAPLN3 logistic regression model, with an area under these curves of 0.97, which showed a sensitivity of 94%, and a specificity of 93% after external validation. CONCLUSION: We created and validated a multigene model for the classification of benign and malignant prostate tissue. With false positive and negative rates below 7%, this three-gene biomarker represents a promising basis for more accurate prostate cancer diagnosis.

4-Bromo-1,8-naphthalimide derivatives as fluorogenic substrates for live cell imaging of glutathione S-transferase (GST) activity.

Fluorogenic substrates are used to visualize the activity of cancer-associated enzymes and to interpret biological events. Certain types of glutathione S-transferase (GST), such as Pi class GST (referred to as GSTP1), are more highly expressed in a wide variety of human cancer tissues compared to their corresponding normal tissues. Pi class GST is thus a cancer cell molecular marker and potential target for overcoming resistance to chemotherapy. Here, we report that 4-bromo-1,8-naphthalimide (BrNaph) is a practical fluorogenic GST substrate. We have found that HE-BrNaph, an N-hydroxyethyl derivative, shows remarkable fluorescence enhancement upon GST-catalyzed SNAr replacement of the bromo group with a glutathionyl group. This substitution was highly selective and occurred only in the presence of GSH/GSTs; no non-enzymatic reaction was observed. We demonstrated that HE-BrNaph allows visualization of GST activity in living cells and enables to distinguish cancer cells from normal cells. Further, various N-substitutions in BrNaph retain susceptibility to enzymatic activity and isozyme selectivity, suggesting the applicability of BrNaph derivatives. Thus, BrNaph and its derivatives are GST substrates useful for fluorescence imaging and the intracellular detection of GSTP1 activity in living cells.

Urinary biomarkers predict advanced acute kidney injury after cardiovascular surgery.

BACKGROUND: Acute kidney injury (AKI) after cardiovascular surgery is a serious complication. Little is known about the ability of novel biomarkers in combination with clinical risk scores for prediction of advanced AKI. METHODS: In this prospectively conducted multicenter study, urine samples were collected from 149 adults at 0, 3, 6, 12 and 24 h after cardiovascular surgery. We measured urinary hemojuvelin (uHJV), kidney injury molecule-1 (uKIM-1), neutrophil gelatinase-associated lipocalin (uNGAL), α-glutathione S-transferase (uα-GST) and π-glutathione S-transferase (uπ-GST). The primary outcome was advanced AKI, under the definition of Kidney Disease: Improving Global Outcomes (KDIGO) stage 2, 3 and composite outcomes were KDIGO stage 2, 3 or 90-day mortality after hospital discharge. RESULTS: Patients with advanced AKI had significantly higher levels of uHJV and uKIM-1 at 3, 6 and 12 h after surgery. When normalized by urinary creatinine level, uKIM-1 in combination with uHJV at 3 h post-surgery had a high predictive ability for advanced AKI and composite outcome (AUC = 0.898 and 0.905, respectively). The combination of this biomarker panel (normalized uKIM-1, uHJV at 3 h post-operation) and Liano's score was superior in predicting advanced AKI (AUC = 0.931, category-free net reclassification improvement of 1.149, and p <  0.001). CONCLUSIONS: When added to Liano's score, normalized uHJV and uKIM-1 levels at 3 h after cardiovascular surgery enhanced the identification of patients at higher risk of progression to advanced AKI and composite outcomes.

Evaluation of NMP22 in bladder cancer patients sensitive to environmental toxins.

BACKGROUND: Bladder cancer (BC) is recognized as environmentally related. The interaction of environmental exposure to chemicals and genetic susceptibility seem to play important roles in BC development. In order to improve diagnosis and the recognition of BC risk, a group of markers which combine genetic susceptibility with detoxification and nuclear matrix protein (NMP22) is proposed. OBJECTIVES: The aim of the study was to examine the utility of nuclear matrix protein (NMP22) as a diagnostic marker in BC in genetic susceptibility (NAT2 slow acetylators) combined with detoxification abilities (glutathione S-transferase GST and isoenzyme GST-π). MATERIAL AND METHODS: The NMP22 level in urine, N-acetyltransferase 2 (NAT2) genotype and GST activity in hemolysate blood, as well as isoenzyme GST-π level, were determined in the urine and serum of 43 patients with BC and from 25 non-cancer controls. NMP22 and isoenzyme GST-π levels were measured by ELISA. The NAT2 genotype was examined in DNA isolated from whole blood using the PCR (Polymerase Chain Reaction) technique, while the activity of GST was determined with the spectrophotometric method. RESULTS: In the BC group, NMP22 (p = 0.005) concentration, GST-π (p = 0.003) in urine and GST (p = 0.009) activity in blood were statistically significantly higher than in the healthy controls. The majority of BC patients were slow acetylators (NAT2 genotype). A correlation between the level of nuclear matrix protein NMP22 and GST was found in all BC group (p = 0.007) and also slow acetylators (p = 0.0147). CONCLUSIONS: The results support the utility of a marker combination, which covers the genetic susceptibility to chemicals with the level of detoxification and nuclear matrix protein in BC patients. A relationship between NMP22 level in urine, GST level in blood and NAT2 genotype was observed. Also the isoenzyme GST-π in urine seems useful as a marker of BC.

Profiling of antioxidative enzyme expression induced by various food components using targeted proteome analysis.

SCOPE: A method was developed for targeted proteome analysis of the expression profile of a set of antioxidative enzymes in rat macrophages and applied to screen the antioxidative potential of several food components/foods. METHODS AND RESULTS: Expression profiles of heme oxygenase 1, peroxiredoxin 1, thioredoxin reductase 1, glutathione reductase, glutathione-S transferase P1, and superoxide dismutase 1 were analyzed by nanoLC-MS/MS in selected scheduled reaction monitoring (sSRM) mode monitoring two to three peptides per protein and three transitions per peptide. Relative quantification was performed by metabolic labeling. The validated method was used to profile the activity of capsaicin, carnosol, diallyl trisulfide, maslinic acid, quercetin, sulforaphane, cinnamaldehyde and coffee extract to modulate the expression levels of antioxidative enzymes. Carnosol and sulforaphane most effectively induced protein expression, leading to upregulation of at least five out of the six antioxidative enzymes by a maximum factor of 22.80 ± 6.71 (heme oxygenase 1 by carnosol). Heme oxygenase 1 was most susceptible to nutritive modulation, whereas glutathione reductase expression rates were hardly affected. CONCLUSION: Targeted mass proteome analysis allows comprehensive evaluation of antioxidative effects by food ingredients. Simultaneous expression analysis of a set of proteins provided valuable insights how various enzymes were differently affected by food components.

Oxidative stress parameters in juvenile brazilian flounder Paralichthys orbignyanus (Valenciennes, 1839) (Pleuronectiformes: Paralichthyidae) exposed to cold and heat shocks

The aim of this study was to determine oxidative stress parameters in the liver and gill of Brazilian flounder juveniles (307.0 ± 16.0 g and 30.0 ± 4.0 cm) submitted to different water temperature (17.1, 23.0 and 28.8ºC) for 72 h and maintained at salinity 25‰. After the acclimation of 7 days, in 23ºC, fish were transferred to 200 L tanks containing seawater (salinity 25‰) at 28.8ºC (heat shock), 17.1ºC (cold shock) or 23.0ºC (control), five replicates (five fish tank-1). The sampled collection occurred in 0 (pre-challenge), 3, 24, 48 and 72 h after temperature shock. Flounder exposed to 17.1ºC and 28.8ºC showed significantly higher TBARS levels and GST activity in the liver post-exposition (PE) in relation to the control (23ºC). CAT activity in liver present a significantly increase at 17.1ºC, in first 48 h, and subsequently decrease in 72 h PE in relation to 28.8ºC. The gills of flounder showed significantly higher TBARS levels, GST and CAT activity when submitted at 17.1 and 28.8ºC in relation to 23.0ºC. There were observed changes in lipid peroxidation levels (LPO), CAT and GST activities in the liver and gill of Brazilian flounder in response to reactive oxygen species (ROS) produced by thermal shocks.

O objetivo deste estudo foi determinar os parâmetros de estresse oxidativo no fígado e brânquias de juvenis de linguado (307,0 ± 16,0 g e 30,0 ± 4,0 cm) submetidos a diferentes temperaturas da água (17,1, 23,0 e 28,8ºC) por 72 h e mantidos na salinidade de 25‰. Após uma aclimatação de sete dias, em 23ºC, os peixes foram transferidos para tanques de 200 L contendo água do mar (salinidade 25‰) em 28,8ºC (choque quente), 17,1ºC (choque frio) ou 23,0ºC (controle), cinco repetições (cinco peixes/tanque). A coleta de amostras ocorreu em 0 (pré-exposição), 3, 24, 48 e 72 h após o choque térmico. O linguado exposto a 17,1ºC e 28,8ºC apresentaram um significante aumento dos níveis de TBARS e atividade da GST no fígado pós-exposição (PE) em relação ao controle (23ºC). A atividade da CAT no fígado apresentou um aumento significativo em 17,1ºC, nas primeiras 48 h, e subsequente diminuição em 72 h PE em relação a 28,8ºC. As brânquias do linguado apresentaram significante aumento dos níveis de TBARS e atividade da GST e CAT quando submetidos a 17,1ºC e 28,8ºC em relação a 23,0ºC. Foram observadas alterações nos níveis de peroxidação lipídica (LPO) e atividade de GST e CAT no fígado e brânquias de linguado em resposta as espécies reativas de oxigênio (ROS) produzidas pelo choque térmico.

The effect of CYP1A1 and GSTP1 isozymes on the occurrence of aortic aneurysms.

BACKGROUND: Aortic aneurysms are vascular diseases that are associated with high mortality and morbidity. Cytochrome P450 CYP1A1 and glutathione S-transferase (GSTP1) isozymes were searched and compared with the patients who had experienced aortic surgery due to aortic aneurysm and atherosclerotic patients without aneurysm to find the relation of the oxidative stress with the aneurysms. MATERIALS AND METHODS: Study group consisted of the patients with the diagnosis of aortic aneurysm (group I, n: 12) and control group who were operated for coronary bypass surgery: preoperatively drug users (group II, n: 21) and nonusers (group III, n: 15). Paraffin sections (4 µm thick) of aortic biopsy materials were stained with hematoxylin and eosine, CYP1A1 and GSTP1 immunohistochemical markers. The specimens were evaluated using light microscopy at 40- to 400-fold magnification. RESULTS: The expressions of CYP1A1 and GSTP1 isozymes were found statistically significantly higher in the patients who have an aortic aneurysm than both the control groups (p < 0.05). There was no significant association between protein expressions, drugs and duration of usage, patient's demographic variables, and smoking (p > 0.05). CONCLUSIONS: In this pioneering study, CYP1A1 and GSTP1 isozymes are related with the aneurysms. The strategy that prevents the oxidative stress for the patients who had aortic aneurysms could be a valuable choice of searching to effect the aneurysmal progression.

Chronically sun-damaged melanomas express low levels of nuclear glutathione-S-transferase-π: an epidemiological and clinicopathological study in Italy.

The detoxifying enzyme glutathione-s-transferase pi (GST-π) is present in keratinocytes and melanocytes and exerts a protective role against tumour progression. Melanomas close to melanocytic naevus remnants occur less frequently on sun-exposed areas, whereas solar dermal elastosis, hallmark of chronic sun-damage, characterise melanomas on sun-exposed skin. We evaluated the expression of GST-π in 113 melanomas associated to melanocytic naevus remnants or to solar dermal elastosis, classified according to clinical characteristics, history of sun exposure, histological subtypes and AJCC staging. Chronically sun-damaged melanomas, identified by moderate-severe solar dermal elastosis, showed a lower nuclear GST-π expression and a higher thickness than those related to melanocytic naevus remnants (p < 0.03). Multivariate logistic regression analysis demonstrated that male gender and chronic sun-exposure are independent risk factors significantly associated to melanomas localised on the trunk (OR = 3.36, 95% CI: 1.31-8.65; OR = 5.97, 95% CI: 1.71-20.87). If confirmed on a larger series, lower expression of nuclear GST-π in melanoma cells could represent a possible marker of chronically sun-damaged melanoma pathogenesis.

Autophagy and redox status in carcinoma of an unknown primary.

AIM AND BACKGROUND: The purpose of the study was to investigate the role and clinical implications of autophagy and reactive oxygen species-related proteins in carcinoma of an unknown primary (CUP). METHODS AND STUDY DESIGN: Tissue microarray was constructed for a total of 77 CUP cases. Immunohistochemical stains conducted were as follows: autophagy-related beclin-1, LC3A, LC3B, and p62; redox-related catalase, thioredoxin reductase, glutathione S-transferase π, thioredoxin-interacting protein, and manganese superoxide dismutase. Immunohistochemical results were then related to their clinicopathologic parameters. RESULTS: The degree of LC3A expression showed a difference according to histologic subtype. In undifferentiated carcinoma, LC3A had the highest expression and adenocarcinoma had the lowest expression (P = 0.021). According to clinical subtype, there was a significant difference between LC3A and glutathione S-transferase π in expression. LC3A had the highest expression in single-organ types and the lowest in intermediate and carcinomatosis types (P = 0.003). Glutathione S-transferase π showed the highest expression in nodal-type tumors and the lowest in carcinomatosis types (P = 0.010). In univariate analysis, shorter overall survival was related to tumor glutathione S-transferase π negativity (P = 0.030). CONCLUSIONS: Different expression levels of the autophagy and reactive oxygen species-related proteins, LC3A and glutathione S-transferase π, were observed according to histologic and/or clinical subtype of carcinoma of an unknown primary.

BRCA1 promoter methylation of normal breast epithelial cells as a possible precursor for BRCA1-methylated breast cancer.

The breast cancer susceptibility gene 1 (BRCA1) and glutathione S-transferase P1 (GSTP1) promoters are reportedly often methylated in breast cancer tissues. Their methylation status in surrounding normal breast tissues has not been examined thoroughly although this may well be important for a better understanding of breast carcinogenesis. In this study, BRCA1 and GSTP1 promoter methylation was examined by methylation-specific PCR assay. Patients with BRCA1-methylated (n = 15) or BRCA1-unmethylated (n = 15) tumors and those with GSTP1-methylated (n = 9) or GSTP1-unmethylated (n = 11) tumors were included in the present study. Methylation status of manually micro-dissected normal epithelial cells from the formalin-fixed paraffin-embedded sections of normal breast tissues adjacent to and distant from the tumors was examined at multiple sites (n = 1-5). Of the 15 patients with BRCA1-methylated tumors, 9 harbored BRCA1 promoter methylation in at least one site of the normal breast tissues. However, no BRCA1 promoter methylation was observed at any site of the normal tissues of the 15 patients with BRCA1-unmethylated tumors. No GSTP1 promoter methylation was observed in the normal tissues regardless of the methylation status of the tumors. The presence of BRCA1 promoter methylation in the normal tissues was confirmed in the epithelial cells enriched with the magnetic-activated cell sorting method. Our findings suggest that a small proportion of normal breast epithelial cells with BRCA1 promoter methylation can be precursor cells from which BRCA1-methylated breast tumors may originate. This does not apply to GSTP1 promoter methylation.

Polymorphism of the glutathione S-transferase P1 gene (GST-pi) in breast carcinoma.

Breast carcinoma is the most common cancer and cause of death among females worldwide, including Jordan. The risk factors for breast carcinoma are linked to DNA mutation and failure of DNA repair or detoxification systems. Identification of susceptibility factors that predispose individuals to breast carcinoma if they are exposed to particular environmental agents might give further insight into the etiology of this malignancy. The glutathione S-transferase (GST) enzyme family detoxifies carcinogenic compounds. Several genes that code for these enzymes are polymorphic, with particular genotypes previously shown to confer an increased carcinoma risk. The present study investigates GST-pi polymorphism in 100-tissue samples previously diagnosed as breast carcinoma, and in 48 non-cancer age-matched breast tissues, using the restriction fragment length polymorphism (RFLP) method for the polymerase chain reaction (PCR) product. Among breast cancer cases, 58%, 40% and 2% were homozygous (Ile/Ile), heterozygous (Ile/Val) and homozygous (Val/Val) respectively. In the control group, 58%, 37.5% and 4.2% were homozygous (Ile/Ile), heterozygous (Ile/Val), and homozygous (Val/Val) respectively. Our results did not support the involvement of GST-pi gene polymorphism in susceptibility to breast carcinoma in the tested North Jordanian female population.

Probing for DNA methylation with a voltammetric DNA detector.

A label-free electrochemical detection of DNA hybridization is used for probing synthetic methylated ssDNA 27-mer or 33-mer targets from the GSTP1-gene. The method is based on electrostatic modulation of the anion-exchange kinetics of a polypyrrole bilayer film deposited on platinum-microelectrodes to which a synthetic single-stranded 15-mer GSTP-1 promoter probe DNA has been attached (DNA detector). The effect of the contact of this DNA-detector with non-methylated and methylated complementary DNA sequences in Tris-buffer is compared using cyclic voltammetry (CV). The DNA-hybridization taking place at the electrode surface leads to a significant decrease of the CV area recorded after exposure to complementary target DNA in comparison to the CV change recorded for non-complementary DNA target. The performance of this miniaturized DNA detector was optimized with respect to hybridization time, temperature, and concentration of the target. It was also evaluated with respect to selectivity, sensitivity, and reproducibility. These results are significant for their possible use as a screening test for hypermethylated DNA sequences.

The effect of caffeic acid phenethyl ester analogues in a modified resistant hepatocyte model.

We present a study of the chemoprotective effects of two caffeic acid phenethyl ester (CAPE)-related structures: LQM717 and LQM706. The modified resistant hepatocyte model in rats was used to study the chemoprevention of these CAPE analogues, which are inexpensive and easily obtained. In the liver cancer model used, we detected extensive necrosis and lipid peroxidation after 24 h, many altered hepatic foci, putatively preneoplastic lesions with γ-glutamyl transpeptidase staining after 30 days, and liver tumors at 12 months. We tested the effect of the CAPE analogues on necrosis, lipid peroxidation, proliferation, p65 activation, altered hepatic foci, and tumors. Both compounds exerted protective effects on lipid peroxidation, necrosis, cell proliferation, p65 activation, and preneoplastic lesions. Rats under a carcinogenic protocol showed a 52, 71.74, and 51.6% decrease in the number of preneoplastic nodules when pretreated with CAPE, LQM706, and LQM717, respectively. At 12 months after carcinogenic treatment, eight of eight rats developed liver cancer, whereas in the group of rats that received pretreatment with CAPE, LQM706, or LQM717, 62.5, 83.3, or 42.85%, respectively, had tumors. In conclusion, LQM717 has the potential to enhance chemoprotection activity much better than CAPE by markedly reducing the formation of liver cancers in this model, and this is a compound that is easy to obtain.

Morphoproteomic confirmation of an activated nuclear factor-кBp65 pathway in follicular thyroid carcinoma.

The role of nuclear factor (NF)-кBp65 pathway in the pathogenesis of follicular thyroid carcinoma (FTC) has not been fully investigated. We retrieved 10 cases of FTC from our file. Tissue microarrays (TMAs) were constructed using 2.0 mm cores from formalin-fixed, paraffin-embedded tissue blocks. TMA sections were immunohistochemically stained for phosphorylated (p)-NF-кBp65 (Ser 536), cyclooxygenase-2 (COX-2), IL-8, and glutathione S-transferase (GST)-pi. Staining intensity (0-3+), extensiveness (0-100%) and subcellular compartmentalization were evaluated. Both nuclear and cytoplasmic immunoreactivities with p-NF-кBp65 (Ser 536) antibodies were observed in all 10 cases, including moderate to strong nuclear staining intensity with a range of extensiveness in 20% - 100% of tumor cells. Moderate (2+) or strong (3+) cytoplasmic expressions of COX-2 and IL-8 were present in 60-100% and 50- 100% of tumor cells, respectively, in all cases. GST-pi was diffusely (70-100%) and moderately or strongly staining the tumor cytoplasm in all cases (except one case with insufficient tissue) with three of them demonstrating nuclear positivity as well. Morphoproteomic analysis reveals the constitutive activation of the NF-кBp65 pathway in follicular thyroid carcinomas as evidenced by phosphorylation at Ser 536 with nuclear translocation and with correlative expression of transcriptionally activated gene products (COX-2, IL-8, and GST-pi). This observation may provide a molecular basis for the tumor biology and targeted therapies for follicular thyroid carcinoma.

Predictive value of expression of ERCC 1 and GST-p for 5-fluorouracil/oxaliplatin chemotherapy in advanced colorectal cancer.

BACKGROUND/AIMS: The aim of this study was to determine whether expression of the excision repair cross complementing protein (ERCC1), glutathione S-transferase pi (GST-p) and thymidylate synthase (TS) predict response in patients with advanced colorectal cancer treated with 5-fluorouracil/oxaliplatin chemotherapy. METHODOLOGY: The study population consisted of 39 patients with advanced colorectal cancer (median age, 65 years). Patients were treated with the modified FOLFOX 6 regimen. The expression of ERCC-1, GST-p and TS of primary tumors were examined by immunohistochemistry. RESULTS: The response rate of modified FOLFOX 6 chemotherapy was 51.3%. The positive rates of ERCC-1, GST-p and TS were 43.6%, 33.3% and 66.7%, respectively. The patients without ERCC-1 (p=0.0248) or GST-p? (p=0.0019) expression were more likely to respond to chemotherapy. TS expression did not correlate with chemotherapeutic response. CONCLUSIONS: Immunohistochemical studies for ERCC-1 and GST-p may be useful in prediction of the response to 5-fluorouracil/oxaliplatin chemotherapy in advanced colorectal cancer patients.

Electrochemical DNA biosensor for detecting cancer biomarker related to glutathione S-transferase P1 (GSTP1) hypermethylation in real samples.

An electrochemical genosensor for the detection of hypermethylation of the glutathione S-transferase P1 (GSTP1) gene, a specific marker of prostate cancer, was reported. This new sensor was used in combination with a single-use carbon graphite working electrode and differential pulse voltammetry, with the results of sample analysis based on the guanine oxidation signals obtained at +1.0 V before and after hybridization between probe and synthetic target or denatured PCR samples. The detected DNA hybridization was also characterized by electrochemical impedance spectroscopy with potassium ferri/ferrocyanide as a redox probe. The protocol consisted of 2 different modes: (i) capture probes selective for methylation-specific and unmethylated GSTP1 sequences were immobilized onto the sensor directly, and hybridization was formed on the electrode surface; (ii) probe/target or probe/noncomplementary target couples were mixed in solution phase, and the transducer was modified through simple adsorption. The limit of detection (S/N=3) was calculated as 2.92 pmol of target sequence in a 100-µl reaction volume. The optimum analytical detection parameters for the biosensor, as well as its future prospects, were also presented.

Low-dose carcinogenicity of 2-amino-3-methylimidazo[4,5-f ]quinoline in rats: Evidence for the existence of no-effect levels and a mechanism involving p21(Cip / WAF1).

The carcinogenicity of the low amounts of genotoxic carcinogens present in food is of pressing concern. The purpose of the present study was to determine the carcinogenicity of low doses of the dietary genotoxic carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and to investigate mechanisms by which IQ exerts its carcinogenic effects. A total of 1595 male F344 rats were divided into seven groups and administered with IQ at doses of 0, 0.001, 0.01, 0.1, 1, 10 and 100 p.p.m. in the diet for 16 weeks. We found that IQ doses of 1 p.p.m. and below did not induce preneoplastic lesions in either the liver or the colon, while IQ doses of 10 and 100 p.p.m. induced preneoplastic lesions in both of these organs. These results demonstrate the presence of no-effect levels of IQ for both liver and colon carcinogenicity in rats. The finding that p21(Cip/WAF1) was significantly induced in the liver at doses well below those required for IQ mediated carcinogenic effects suggests that induction of p21(Cip/WAF1) is one of the mechanisms responsible for the observed no-effect of low doses of IQ. Furthermore, IQ administration caused significant induction of CYP1A2 at doses of 0.01-10 p.p.m., but administration of 100 p.p.m. IQ induced CYP1A1 rather than CYP1A2. This result indicates the importance of dosage when interpreting data on the carcinogenicity and metabolic activation of IQ. Overall, our results suggest the existence of no-effect levels for the carcinogenicity of this genotoxic compound.