The GSTM1 null genotype confers an increased risk for solar keratosis development in an Australian Caucasian population

Glutathione S-transferase expression in benign and malignant eyelid tumors

Eyelid tumors commonly originate from the skin and its appendages. Environmental toxins and oxidants affect eyelid carcinogenesis. Glutathione S-transferases (GST) are antioxidants that participate in pathogenesis. We investigated GST levels in malignant and benign eyelid tumors in otherwise healthy individuals. We used 57 malignant eyelid biopsies, benign eyelid biopsies, and tissue removed during blepharoplasty and entropion operations culled from pathology archives. Specimens were divided into three groups: malignant lesions, benign lesions and controls consisting of eyelid tissue removed during routine blepharoplasty and entropion surgery. Specimens were immunostained for seven GST (GST-A, GST-P, GST-Z, GST-S, GST-K, GST-O, GST-T) and the intensity of staining was quantified. In the malignant group, GST-O and GST-P staining was less intense than for the control group. In the benign group, the GST-P level was less than for the control group. We found no significant difference between the intensity of staining in malignant and benign groups. Our findings suggest that GST-O and GST-P enzymes may play significant roles in eyelid carcinogenesis.

Expressions of glutathione S-transferase alpha, mu, pi, and theta in the skin samples of patients with acne rosacea

BACKGROUND

Data point to the importance of oxidative stress in rosacea. Glutathione S-transferases (GSTs) have substantial roles in a wide variety of oxidative stress-related conditions.

AIM

To evaluate the immunohistochemical staining characteristics of GST alpha (GSTA), mu (GSTM), pi (GSTP), and theta (GSTT) in patients with rosacea.

PATIENTS/METHODS

The study included 23 women and 7 men with rosacea (mean ± SD age 49 ± 11 year) and 15 healthy control subjects (10 women, 5 men; mean ± SD age 47.86 ± 10.88 year). For each patient, the average disease duration, disease subtype, ocular involvement, and severity score were recorded. A 3-mm punch biopsy was taken from the facial skin of each patient and control. Expression of GST isoenzymes was analyzed immunohistochemically.

RESULTS

Expressions of GSTM1, GSTP1, and GSTT1 were significantly elevated in patients with rosacea compared to those in the control group (P = .0001, P = .0002, P < .0001, respectively). In the rosacea group, GSTT1 expression was significantly stronger than GSTP1 and GSTA1 expressions (P = .019, P < .0001, respectively). There were no significant associations between expressions of GST isoenzymes and gender, age, average duration of illness, disease subtype, ocular involvement, or severity score in the patient group (all P > .05).

CONCLUSIONS

In rosacea, the significant increase of GSTT1, GSTP1, and GSTM1 expressions might result from activation of GST as an outcome of extreme free radical generation from triggered neutrophils or ultraviolet vulnerability. These findings support the relevance of oxidant stress in the pathogenesis of rosacea.

The prognostic impact of GSTM1/GSTP1 genetic variants in bladder Cancer

Background

The glutathione S-transferases (GSTs) are a superfamily of phase II detoxifying enzymes that inactivates a wide variety of potential carcinogens through glutathione conjugation. Polymorphic changes in the GST genes have been reported to be associated with increased susceptibility to cancer development and anticancer drug resistance. In this study, we investigated the association between genetic variants in GSTM1 and GSTP1 and patients’ clinicopathological parameters. The prognostic values of such associations were evaluated among bladder cancer patients.

Methods

Genotyping of GSTM1 and GSTP1 in bladder cancer patients was assessed using polymerase chain reaction followed by DNA sequencing. Overall survival was estimated using the Kaplan-Meier method and multiple logistic regression and correlation analysis were performed.

Results

The GSTM1 null genotype was significantly associated with poor overall survival compared with the wild-type GSTM1 genotype. There was a trend towards better overall survival in patients with wild-type GSTP1 allele (AA) compared with GSTP1 (AG/GG) genotype. Interestingly, Kaplan-meier survival curve for GSTM1 null patients adjusted for sub-cohort with amplified HER2 gene showed poor survival compared with the GSTM1 null/ non-amplified HER2 gene. Also the same population when adjusted with HER2 protein expression, data showed poor survival for patients harboring GSTM1 null/high HER2 protein expression compared with low protein expression.

Conclusion

This study focuses on the impact of GSTM1 null genotype on bladder cancer patients’ outcome. Further investigations are required to delineate the underlying mechanisms of combined GSTM^−/− and HER2 status in bladder cancer.

Does maternal exposure to artificial food coloring additives increase oxidative stress in the skin of rats?

Glutathione-S-transferase (GST) and cytochrome P450 family 1 subfamily A polypeptide 1 (CYP1A1) metabolize and detoxify carcinogens, drugs, environmental pollutants, and reactive oxygen species. Changes of GST expression in tissues and gene mutations have been reported in association with many neoplastic skin diseases and dermatoses. Widely used artificial food coloring additives (AFCAs) also reported to effect primarily behavioral and cognitive function and cause neoplastic diseases and several inflammatory skin diseases. We aimed to identify the changes in expression of GSTs, CYP1A1, and vascular endothelial growth factor (VEGF) in rat skin which were maternally exposed AFCAs. A rat model was designed to evaluate the effects of maternal exposure of AFCAs on skin in rats. "No observable adverse effect levels" of commonly used AFCAs as a mixture were given to female rats before and during gestation. Immunohistochemical expression of GSTs, CYP1A1, and VEGF was evaluated in their offspring. CYP1A1, glutathione S-transferase pi (GSTP), glutathione S-transferase alpha (GSTA), glutathione S-transferase mu (GSTM), glutathione S-transferase theta (GSTT), and VEGF were expressed by epidermal keratinocytes, dermal fibroblasts, sebaceous glands, hair follicle, and subcutaneous striated muscle in the normal skin. CYP1A1, GSTA, and GSTT were expressed at all microanatomical sites of skin in varying degrees. The expressions of CYP1A1, GSTA, GSTT, and VEGF were decreased significantly, while GSTM expression on sebaceous gland and hair follicle was increased. Maternal exposure of AFCAs apparently effects expression of the CYP1A1, GSTs, and VEGF in the skin. This prominent change of expressions might play role in neoplastic and nonneoplastic skin diseases.

Solar radiation induced skin damage: review of protective and preventive options

PURPOSE

Solar energy has a number of short- and long-term detrimental effects on skin that can result in several skin disorders. The aim of this review is to summarise current knowledge on endogenous systems within the skin for protection from solar radiation and present research findings to date, on the exogenous options for such skin photoprotection.

RESULTS

Endogenous systems for protection from solar radiation include melanin synthesis, epidermal thickening and an antioxidant network. Existing lesions are eliminated via repair mechanisms. Cells with irreparable damage undergo apoptosis. Excessive and chronic sun exposure however can overwhelm these mechanisms leading to photoaging and the development of cutaneous malignancies. Therefore exogenous means are a necessity. Exogenous protection includes sun avoidance, use of photoprotective clothing and sufficient application of broad-spectrum sunscreens as presently the best way to protect the skin. However other strategies that may enhance currently used means of protection are being investigated. These are often based on the endogenous protective response to solar light such as compounds that stimulate pigmentation, antioxidant enzymes, DNA repair enzymes, non-enzymatic antioxidants.

CONCLUSION

More research is needed to confirm the effectiveness of new alternatives to photoprotection such as use of DNA repair and antioxidant enzymes and plant polyphenols and to find an efficient way for their delivery to the skin. New approaches to the prevention of skin damage are important especially for specific groups of people such as (young) children, photosensitive people and patients on immunosuppressive therapy. Changes in public awareness on the subject too must be made.

Cigarette smoking, oxidative stress, the anti-oxidant response through Nrf2 signaling, and Age-related Macular Degeneration

Age-related Macular Degeneration (AMD) is the leading cause of blindness among the elderly. While excellent treatment has emerged for neovascular disease, treatment for early AMD is lacking due to an incomplete understanding of the early molecular events. Cigarette smoking is the strongest epidemiologic risk factor, yet we do not understand how smoking contributes to AMD. Smoking related oxidative damage during the early phases of AMD may play an important role. This review explores how cigarette smoking and oxidative stress to the retinal pigmented epithelium (RPE) might contribute to AMD, and how the transcription factor Nrf2 can activate a cytoprotective response.

Pathology and pathobiology of actinic (solar) keratosis - an update

Actinic keratosis is a UV light-induced lesion and develops mostly in fair-skinned patients being susceptible to solar damage. The term actinic keratosis (AK) describes clinically ill-defined reddish to reddish-brown scaly lesions on erythematous base in areas damaged severely by sunlight. The term does not imply anything about the biology or histopathology. Actinic keratoses (AKs) have been recognized as precursor of cancer or of precancerous lesions in the past but today they are considered as an early in situ squamous cell carcinoma (1,2) and are categorized in several classifications with subdivisions into three grades depending on the amount of atypical keratinocytes in the epidermis.(3-6) The incidence of development of AK in caucasians increases with age, proximity to the equator and outdoor occupation. Australia has the highest skin cancer rate in the world. AKs are discovered in up to 40-50% of the Australian population older than 40 years.(7) AKs are the most common malignant lesion of the skin.(8-12).

GSTM1 and APE1 genotypes affect arsenic-induced oxidative stress: a repeated measures study

BACKGROUND

Chronic arsenic exposure is associated with an increased risk of skin, bladder and lung cancers. Generation of oxidative stress may contribute to arsenic carcinogenesis.

METHODS

To investigate the association between arsenic exposure and oxidative stress, urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) was evaluated in a cohort of 97 women recruited from an arsenic-endemic region of Bangladesh in 2003. Arsenic exposure was measured in urine, toenails, and drinking water. Drinking water and urine samples were collected on three consecutive days. Susceptibility to oxidative stress was evaluated by genotyping relevant polymorphisms in glutathione-s transferase mu (GSTM1), human 8-oxoguanine glycosylase (hOGG1) and apurinic/apyrimidinic endonuclease (APE1) genes using the Taqman method. Data were analyzed using random effects Tobit regression to account for repeated measures and 8-OHdG values below the detection limit.

RESULTS

A consistent negative effect for APE1 was observed across water, toenail and urinary arsenic models. APE1 148 glu/glu + asp/glu genotype was associated with a decrease in logged 8-OHdG of 0.40 (95%CI -0.73, -0.07) compared to APE1 148 asp/asp. An association between total urinary arsenic and 8-OHdG was observed among women with the GSTM1 null genotype but not in women with GSTM1 positive. Among women with GSTM1 null, a comparison of the second, third, and fourth quartiles of total urinary arsenic to the first quartile resulted in a 0.84 increase (95% CI 0.27, 1.42), a 0.98 increase (95% CI 033, 1.66) and a 0.85 increase (95% CI 0.27, 1.44) in logged 8-OHdG, respectively. No effects between 8-OHdG and toenail arsenic or drinking water arsenic were observed.

CONCLUSION

These results suggest the APE1 variant genotype decreases repair of 8-OHdG and that arsenic exposure is associated with oxidative stress in women who lack a functional GSTM1 detoxification enzyme.

GSTM1 and GSTT1 null genotypes as possible heritable factors of rosacea

PURPOSE

Rosacea might be related to an increased activity of reactive oxygen species (ROS) and deficient function of the antioxidant system. Glutathione S-transferases (GSTs) play a primer role in cellular defense against electrophilic chemical species and radical oxygen species. We hypothesized that increased ROS activity or decreased antioxidant potential, possibly induced by GST gene polymorphism, might have a pathogenic role in rosacea.

METHODS

The study group consisted of 45 patients with rosacea and 100 control subjects. DNA samples were isolated from blood samples using high pure polymerase chain reaction (PCR) Template preparation Kit. The GSTM1, GSTT1, and P1 polymorphisms were detected using a real-time PCR and fluorescence resonance energy transfer with a Light-Cycler Instrument. Associations between specific genotypes and the development of rosacea were examined using logistic regression analyses to calculate odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

GSTM1 and GSTT1 null genotypes were found to be statistically different from control (P=0.005, P=0.009, respectively), and associated with an increased risk of rosacea (OR [95% CI]: 2.84 [1.37-5.89]; OR [95% CI]: 2.68 [1.27-5.67], respectively). There was a statistically significant relationship between both null combination of the GSTM1 and GSTT1 genotype polymorphisms and rosacea (P=0.003, OR [95% CI]: 4.18 [1.57-11.13]). There were no statistically significant differences between patient and control groups for the GSTP1 Ile/Ile, Ile/Val, and Val/Val genotypes (P>0.05).

CONCLUSION

We demonstrated a significant association between the GSTT1 and/or GSTM1 null genotypes and rosacea. However, the potential role of GSTs as markers of susceptibility to rosacea needs further studies in larger patient groups.