γ-Glutamyltransferase and Breast Cancer Risk Beyond Alcohol Consumption and Other Life Style Factors - A Pooled Cohort Analysis

Catabolism of extracellular glutathione supplies amino acids to support tumor growth

Restricting amino acids from tumors is an emerging therapeutic strategy with significant promise. While typically considered an intracellular antioxidant with tumor-promoting capabilities, glutathione (GSH) is a tripeptide of cysteine, glutamate, and glycine that can be catabolized, yielding amino acids. The extent to which GSH-derived amino acids are essential to cancers is unclear. Here, we find that GSH catabolism promotes tumor growth. We show that depletion of intracellular GSH does not perturb tumor growth, and extracellular GSH is highly abundant in the tumor microenvironment, highlighting the potential importance of GSH outside of tumors. We find supplementation with GSH can rescue cancer cell survival and growth in cystine-deficient conditions, and this rescue is dependent on the catabolic activity of γ-glutamyltransferases (GGTs). Finally, pharmacologic targeting of GGTs' activity prevents the breakdown of circulating GSH, lowers tumor cysteine levels, and slows tumor growth. Our findings indicate a non-canonical role for GSH in supporting tumors by acting as a reservoir of amino acids. Depriving tumors of extracellular GSH or inhibiting its breakdown is potentially a therapeutically tractable approach for patients with cancer. Further, these findings change our view of GSH and how amino acids, including cysteine, are supplied to cells.

Therapeutic impact of purified Trichoderma viride L-asparaginase in murine model of liver cancer and in vitro Hep-G2 cell line

BACKGROUND

Hepatocellular carcinoma (HCC) is among the common cancers, but difficult to diagnose and treat. L-asparaginase has been introduced in the treatment protocol of pediatric acute lymphoblastic leukemia (ALL) since the 1960s with a good outcome and increased survival rates to nearly 90%. Moreover, it has been found to have therapeutic potential in solid tumors. Production of glutaminase-free-L-asparaginase is of interest to avoid glutaminase-related toxicity and hypersensitivity. In the current study, an extracellular L-asparaginase that is free of L-glutaminase was purified from the culture filtrate of an endophytic fungus Trichoderma viride. The cytotoxic effect of the purified enzyme was evaluated in vitro against a panel of human tumor cell lines and in vivo against male Wister albino mice intraperitoneally injected with diethyl nitrosamine (200 mg/kg bw), followed by (after 2 weeks) oral administration of carbon tetrachloride (2 mL/kg bw). This dose was repeated for 2 months, and after that, the blood samples were collected to estimate hepatic and renal injury markers, lipid profiles, and oxidative stress parameters.

RESULTS

L-asparaginase was purified from T. viride culture filtrate with 36 purification folds, 688.1 U/mg specific activity, and 38.9% yield. The highest antiproliferative activity of the purified enzyme was observed against the hepatocellular carcinoma (Hep-G2) cell line, with an IC50 of 21.2 g/mL, which was higher than that observed for MCF-7 (IC50 34.2 g/mL). Comparing the DENA-intoxicated group to the negative control group, it can be demonstrated that L-asparaginase adjusted the levels of the liver function enzymes and the hepatic injury markers that had previously changed with DENA intoxication. DENA causes kidney dysfunction and altered serum albumin and creatinine levels as well. Administration of L-asparaginase was found to improve the levels of the tested biomarkers including kidney and liver function tests. L-asparaginase treatment of the DENA-intoxicated group resulted in a significant improvement in the liver and kidney tissues to near normal similar to the healthy control group.

CONCLUSION

The results suggest that this purified T. viride L-asparaginase may be able to delay the development of liver cancer and may be used as a potential candidate for future application in medicine as an anticancer medication.

Preoperative CA19-9 and GGT ratio as a prognostic indicator in ampullary carcinoma

BACKGROUND AND AIMS

In recent years, more and more inflammatory indicators have been studied to predict the long-term survival of patients with ampullary carcinoma (AC) after radical resection, but these prognostic indicators are still controversial. Therefore, based on previous inflammation scores, this study established a novel, easily accessible, more feasible and more predictive prognostic marker [Carbohydrate antigen199 to gamma-glutamyltransferase ratio (CA19-9/GGT)] to better assess the prognostic significance in AC patients undergoing radical resection.

METHODS

Overall survival (OS) and recurrence-free survival (RFS) were analyzed by Cox regression model. Correlation between CA19-9/GGT and clinicopathological variables were analyzed by Chi-squared test, Fisher ' s exact test, independent sample t test and Mann-Whitney U test. The performance of prognostic indexes is compared by the consistency index (C-index). The prediction accuracy of nomogram is further confirmed by calibration curve and decision curve analysis (DCA).

RESULTS

CA19-9/GGT was an independent risk factor affecting OS [P = 0.001, hazard ratio (HR) 2.459, 95% confidence intervals (CI) 1.450-4.167] and RFS (P = 0.002, HR 2.333, 95% CI 1.371-3.971) in multivariate analysis. The optimal cut-off value of CA19-9/GGT was 0.14. In CA19-9/GGT correlation analysis, high risk group (> 0.14) was significantly associated with poor prognosis. The predictive performance of CA19-9/GGT (OS: C-index = 0.753, RFS: C-index = 0.745) was confirmed to be superior to other prognostic indicators according to the C-index. Compared with the simple AJCC staging system, the Nomogram prediction model (OS: C-index = 0.787, RFS: C-index = 0.795) established by the combination of CA19-9/GGT and AJCC 8th TNM staging system has higher prediction accuracy.

CONCLUSIONS

CA19-9/GGT was an independent prognostic indicator after radical resection of AC. Incorporating CA19-9/GGT into the AJCC TNM staging system optimized the prediction accuracy of the TNM staging system, and further verified the predictive value of CA19-9/GGT.

γ-Glutamyltranspeptidase as a Prognostic Biomarker in Advanced Hepatocellular Carcinoma Treated with Transarterial Chemoembolization

PURPOSE

To evaluate the prognostic value of pretreatment serum γ-glutamyltransferase (GGT) level in patients with advanced hepatocellular carcinoma (HCC) receiving transarterial chemoembolization.

MATERIALS AND METHODS

This retrospective study included 140 patients (123 male, 17 female; mean age, 56.9 y ± 12.0; range, 22.0-82.0 y) with Barcelona Clinic Liver Cancer class C HCC who received first-line conventional chemoembolization between December 2013 and March 2018. Patients were divided into low and high GGT groups based on a cutoff value calculated with a receiver operating characteristic curve. Overall survival (OS) was compared between groups by log-rank test. Univariate and multivariate survival analyses were performed.

RESULTS

The optimal cutoff values of GGT were 119.5 U/L in men and 175.0 U/L in women. The 6-, 9-, and 12-mo OS rates were 81.7%, 72.4%, and 62.9%, respectively, for patients in the low GGT group (n = 44) and 58.8%, 35.7%, and 28.8%, respectively, for patients in the high GGT group (n = 96; P < .001). Multivariable Cox regression analysis identified high pretreatment serum GGT level (hazard ratio [HR], 2.71; 95% confidence interval [CI], 1.67-4.40; P < .001), multiple tumors (HR, 3.05; 95% CI, 1.23-7.53; P = .02), and performance of target treatment (ie, sorafenib; HR, 0.41; 95% CI, 0.24-0.72; P = .002) or ablation (HR, 0.35; 95% CI, 0.18-0.66; P = .001) as independent prognostic factors for OS.

CONCLUSIONS

Pretreatment serum GGT level was an independent prognostic factor for OS in patients with advanced HCC treated with chemoembolization, suggesting that GGT is a useful prognostic biomarker for advanced HCC.

Circulating liver enzymes and risks of chronic diseases and mortality in the prospective EPIC-Heidelberg case-cohort study

OBJECTIVES

Elevated liver enzyme concentrations in blood are indicative of liver diseases and may provide an early signal for being at risk for other chronic diseases. Our study aimed to assess the relationships of alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT), alanine aminotransferase (ALT), aspartate transaminase (AST) and the De Ritis ratio (AST/ALT) with incidence and mortality of cardiovascular diseases (CVD) and the four most common cancers, that is, breast, prostate, colorectal and lung.

SETTING, PARTICIPANTS AND OUTCOME MEASURES

We analysed a case-cohort sample of the prospective European Prospective Investigation into Cancer and Nutrition-Heidelberg cohort, including cancer (n=1632), cancer mortality (n=761), CVD (n=1070), CVD mortality (n=381) and a random subcohort (n=2739) with an average follow-up duration of 15.6 years. Concentrations of liver enzymes were measured in prediagnostic blood samples and Prentice-weighted Cox regression models were used to estimate HRs with 95% CIs.

RESULTS

High ALP levels were associated with increased risk for lung cancer and all-cause mortality (highest vs lowest quartile, multivariable adjusted HR=2.39 (95% CI 1.30 to 4.39), HR=1.31 (95% CI 1.02 to 1.67)), high AST levels with all-cause mortality (HR=1.45 (95% CI 1.15 to 1.82)), and a high De Ritis ratio with prostate cancer risk, all-cause and cancer mortality (HR=1.61 (95% CI 1.10 to 2.36), HR=1.60 (95% CI 1.25 to 2.04), HR=1.67 (95% CI 1.26 to 2.23)). Using cut-points for liver enzyme levels above normal, we observed positive associations for all-cause mortality with ALP, GGT and AST, and assigning a combined risk score resulted in positive associations with all-cause and cause-specific mortality.

CONCLUSIONS

Measurements of serum liver enzymes, as routinely performed in health check-ups, may support the identification of individuals at increased risk for all-cause mortality. Further prospective studies are needed to verify our first results on individual cancers and on a combined risk score.

The mercapturic acid pathway

The mercapturic acid pathway is a major route for the biotransformation of xenobiotic and endobiotic electrophilic compounds and their metabolites. Mercapturic acids (N-acetyl-l-cysteine S-conjugates) are formed by the sequential action of the glutathione transferases, γ-glutamyltransferases, dipeptidases, and cysteine S-conjugate N-acetyltransferase to yield glutathione S-conjugates, l-cysteinylglycine S-conjugates, l-cysteine S-conjugates, and mercapturic acids; these metabolites constitute a "mercapturomic" profile. Aminoacylases catalyze the hydrolysis of mercapturic acids to form cysteine S-conjugates. Several renal transport systems facilitate the urinary elimination of mercapturic acids; urinary mercapturic acids may serve as biomarkers for exposure to chemicals. Although mercapturic acid formation and elimination is a detoxication reaction, l-cysteine S-conjugates may undergo bioactivation by cysteine S-conjugate β-lyase. Moreover, some l-cysteine S-conjugates, particularly l-cysteinyl-leukotrienes, exert significant pathophysiological effects. Finally, some enzymes of the mercapturic acid pathway are described as the so-called "moonlighting proteins," catalytic proteins that exert multiple biochemical or biophysical functions apart from catalysis.

The prognostic significance of serum gamma-glutamyltransferase levels and AST/ALT in primary hepatic carcinoma

Background

Blood counting and the liver function tests, as the routine examinations, can reflect the immune and nutritional status of the body, our aim is to assess the prognostic significance of serum gamma-glutamyltransferase (GGT) levels and AST/ALT in primary hepatic carcinoma.

Methods

Clinico-pathological data of 414 patients with primary hepatic carcinoma in the 1st Affiliated Hospital of Anhui Medical College between January 2007 to January 2014 was analyzed retrospectively in this study. Survival curves were described by Kaplan-Meier method and compared by Log-rank test, univariate and multivariate analysis were used to identify the prognostic factors.

Results

GGT was positively correlated with the tumor size(P = 0.000), tumor volume (P = 0.000), tumor volume percent (P = 0.004), TNM stage(P = 0.009), 1-year survival rate (P = 0.000), 3- years survival rate (P = 0.000) and 5-years survival rate(P = 0.000). The serum ALT/AST was significantly correlated with age (P = 0.047), tumor size(P = 0.002), tumor volume (P = 0.010), tumor volume percent (P = 0.005), TNM stage(P = 0.006), liver cirrhosis(P = 0.003), 3- years survival rate (P = 0.032) and 5-years survival rate(P = 0.000). The Kaplan-Meier curves showed that the patients with primary hepatic carcinoma had a longer time in the low GGT group and low AST/ALT group, showing a significant difference (P < 0.05). The univariate and multivariate analyses showed that TNM stage, differentiation grade, tumor volume, GGT and AST/ALT were independent factors for predicting overall survival rate of primary hepatic carcinoma patients.

Conclusions

GGT and AST/ALT were independent factors for predicting overall survival rate of primary hepatic carcinoma patients.

Gamma-glutamyltransferase as a preoperative differential diagnostic marker in patients with adnexal mass

OBJECTIVE

Gamma-glutamyltransferase (GGT) is involved in tumor development, progression and chemotherapy resistance. The present study evaluated GGT serum levels as a preoperative predictive marker for ovarian cancer in patients with adnexal mass.

STUDY DESIGN

Preoperative GGT serum levels of 2235 patients with adnexal mass and subsequent surgery were ascertained (patients with benign ovarian tumors: n = 1811; borderline tumor of the ovary [BTO]: n = 85; epithelial ovarian cancer [EOC]: n = 339). Standardized expert transvaginal ultrasound was documented.

RESULTS

Median (interquartile range) GGT serum levels in patients with benign ovarian tumors, BTO, and EOC were 15.0 U/l (11.0-23.0), 17.0 U/l (10.0-23.5), and 20.0 U/l (13.0-34.0), respectively (p = 0.002). Elevated GGT serum levels were associated with the presence of BTO/EOC in univariate analysis (p < 0.0001, hazard ratio 1.8, confidence interval 1.5-2.3). GGT did not outperform established tools for preoperative prediction of BTO/EOC in patients with adnexal mass, such as CA-125 measurement or transvaginal ultrasound.

CONCLUSION

Elevated GGT serum levels were not associated with the presence of BTO/EOC in women with suspicious adnexal mass in multivariate analysis. GGT serum levels did not outperform established risk factors and therefore might add only limited additional value to CA-125 serum levels in the differential diagnosis between benign and malignant adnexal masses.

Influence of oral contraceptives on lipid profile and paraoxonase and commonly hepatic enzymes activities

BACKGROUND

The aim of the study was to verify the influence of oral contraceptives (OCs) on lipid profile and the arylesterase, lactonase and phosphotriesterase activities of paraoxonase 1 (PON1). Also commonly hepatic enzymes: aspartate aminotransferase (AST), alanine aminotransferase (ALT) and γ-glutamyltranspherase (GGT) were measured.

METHODS

Lipid profile and hepatic enzymes were determined using commercial available reagents. Paraoxonase activities were estimated using earlier published procedures. Blood samples were collected from 120 women of similar age (22.6±1.0 years) with similar BMI (20.71±2.20 kg/m2 ). Participations were divided into two groups: 74 females do not take (group A) and 46 women taking OCs (group B).

RESULTS

Higher triglycerides and lower low-density lipoproteins levels were observed in group B than in group A) (56.9±19.7 mg/dL. Castelli risk index I was significantly higher in group B when compared to group A (P<.0001), whereas we did not observe any statistically significant differences in Castelli risk index II value between studied groups. In group B, increase in ALT, AST and GGT activities were found, while the de Ritis ratio was lower in group B than in group A. In group B, lower phosphotriesterase activity and higher arylesterase and lactonase activities were found when compared to group A.

CONCLUSION

Higher ALT, AST and GGT activities in serum as well as changes in lipid profile and PON activities can indicate that OCs usage can cause disorder in these parameters in the serum of women taking OCs.

Prognostic value of pretreatment serum alanine aminotransferase/aspartate aminotransferase (ALT/AST) ratio and gamma glutamyltransferase (GGT) in patients with esophageal squamous cell carcinoma

BACKGROUND

The levels of liver function tests (LFTs) are often used to assess liver injury and non-liver disease-related mortality. In our study, the relationship between pretreatment serum LFTs and overall survival (OS) was evaluated in esophageal squamous cell carcinoma (ESCC) patients.

METHODS

Our purpose was to investigate the prognostic value of the preoperative alanine aminotransferase/aspartate aminotransferase (ALT/AST) ratio and gamma glutamyltransferase (GGT) in ESCC patients. A retrospective study was performed in 447 patients with ESCC, and follow-up period was at least 60 months until death. The prognostic significance of serum LFTs were determined by univariate and multivariate Cox hazard models.

RESULTS

LFTs including ALT, AST, LSR, GGT, TBA and LDH were analyzed. Serum LSR (HR: 0.592, 95% CI = 0.457-0.768, p < 0.001 and GGT (HR: 1.507, 95% CI = 1.163-1.953, p = 0.002) levels were indicated as significant predictors of OS. The 5-year OS among patients with higher LSR levels was longer compared with those patients with decreased LSR levels, not only in the whole cohort but also in the subgroups stratified by pathological stage (T1-T2 subgroup, T3-T4 subgroup, N0 subgroup and M0 subgroup). We also found that patients with a higher GGT might predict worse OS than patients with a normal GGT, not only in the whole cohort but also in the subgroups stratified by pathological stage (T3-T4 subgroup and N1-N2 subgroup).

CONCLUSIONS

Both increased levels of LSR and decreased levels of GGT might predict shorter overall survival in ESCC patients. Our findings suggest that serum LSR and GGT levels could be used as a key predictor of survival in patients with ESCC.

Gamma-glutamyltransferase-friend or foe within?

Gamma-glutamyltransferase (GGT) is a liver enzyme, which is located on the plasma membranes of most cells and organ tissues, but more commonly in hepatocytes, and is routinely used in clinical practice to help indicate liver injury and as a marker of excessive alcohol consumption. Among the liver enzymes, important advances have especially been made in understanding the physiological functions of GGT. The primary role of GGT is the extracellular catabolism of glutathione, the major thiol antioxidant in mammalian cells, which plays a relevant role in protecting cells against oxidants produced during normal metabolism; GGT, therefore, plays an important role in cellular defence. Beyond its physiological functions, circulating serum GGT has been linked to a remarkable array of chronic conditions and diseases, which include nonalcoholic fatty liver disease, vascular and nonvascular diseases and mortality outcomes. This review summarizes the available epidemiological and genetic evidence for the associations between GGT and these adverse outcomes, the postulated biologic mechanisms underlying these associations, outlines areas of outstanding uncertainty and the implications for clinical practice.