Barna Budai

Chemical aspects of hydrogen sulfide measurements in physiological samples.

BACKGROUND Owing to recent discoveries of many hydrogen sulfide-mediated physiological processes, sulfide biology is in the focus of scientific research. However, the promiscuous chemical properties of sulfide pose complications for biological studies, which led to accumulation of controversial observations in the literature. SCOPE OF REVIEW We intend to provide an overview of fundamental thermodynamic and kinetic features of sulfide redox- and coordination-chemical reactions and protonation equilibria in relation to its biological functions. In light of these chemical properties we review the strengths and limitations of the most commonly used sulfide detection methods and recently developed fluorescent probes. We also give a personal perspective on blood and tissue sulfide measurements based on proposed biomolecule-sulfide interactions and point out important chemical aspects of handling sulfide reagent solutions. MAJOR CONCLUSIONS The diverse chemistries of sulfide detection methods resulted in orders of magnitude differences in measured physiological sulfide levels. Investigations that were aimed to dissect the underlying molecular reasons responsible for these controversies made the important recognition that there are large sulfide reserves in biological systems. These sulfide pools are tightly regulated in a dynamic manner and they are likely to play a major role in regulation of endogenous-sulfide-mediated biological functions and avoiding toxic side effects. GENERAL SIGNIFICANCE Working with sulfide is challenging, because it requires considerable amounts of chemical knowledge to adequately handle reagent sulfide solutions and interpret biological observations. Therefore, we propose that a rigorous chemical approach could aid the reconciliation of the increasing number of controversies in sulfide biology. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn.

Cetuximab, gemcitabine and capecitabine in patients with inoperable biliary tract cancer: A phase 2 study

PURPOSE Biliary tract cancer is rare and has dismal prognosis. Chemotherapy has its role in inoperable disease but the role of targeted agents like cetuximab remains to be defined. On the basis of high epidermal growth factor receptor expression of biliary tract cancers this study aims to investigate the efficacy of cetuximab, gemcitabine and capecitabine in an exploratory phase 2 trial. PATIENTS AND METHODS Inoperable biliary tract cancer patients were treated with the combination of gemcitabine (1000 mg/m(2) on day 1 and 8), capecitabine (1300 mg/m(2)/d on day 1-14) and weekly cetuximab (400mg/m(2) loading and 250 mg/m(2) maintenance dose) in 21-d cycles until progression or the appearance of intolerable side-effects. RESULTS Out of 34 patients (mean age 59.7 years) accrued in this study 16 had intrahepatic, eight extrahepatic cholangiocarcinoma and 10 gall bladder cancer. The best overall response rate was 17.6% (two complete responses and four partial responses) and the clinical benefit rate was 76.5%. After a median of 15.4 months follow-up the median progression free survival was 34.3 weeks and the median overall survival was 62.8 weeks. The performance status and chemotherapy efficacy were independent and significant markers of survival. Only moderate side-effects were registered in this study. KRAS mutation was evaluable in 24 tumours, all of these were of wild type. CONCLUSION The efficacy of cetuximab, gemcitabine and capecitabine combination is encouraging and a well tolerated treatment of inoperable biliary tract cancers.

The association of polymorphisms in 5-fluorouracil metabolism genes with outcome in adjuvant treatment of colorectal cancer

AIM The purpose of this study was to investigate whether specific combinations of polymorphisms in 5-fluorouracil (5-FU) metabolism-related genes were associated with outcome in 5-FU-based adjuvant treatment of colorectal cancer. METHODS We analyzed two cohorts of 302 and 290 patients, respectively, one cohort for exploratory analyses and another cohort for validating the exploratory analyses. A total of ten polymorphisms in genes involved in 5-FU pharmacodynamics and pharmacokinetics were studied. End points were disease-free survival (DFS) and overall survival. Multifactor dimensionality reduction was used to identify genetic interaction profiles associated with outcome. RESULTS Low-expression alleles in thymidylate synthase (TYMS) were associated with decreased DFS and overall survival (DFS:hazard ratio [HR] exploration 2.65 [1.40-4.65]; p = 0.004, HR validation 1.69 [1.03-2.66]; p = 0.03). A specific multifactor dimensionality reduction derived combination of dihydropyrimidine dehydrogenase and TYMS polymorphisms was associated with increased DFS (HR exploration 0.69 [0.49-0.98]; p = 0.04, HR validation 0.66 [0.45-0.95]; p = 0.03). Specific combinations of functional polymorphisms in DPYD and TYMS were demonstrated to be associated with DFS and overall survival in patients receiving adjuvant 5-FU-based treatment. Specifically high TYMS expression alleles seem to be associated with decreased DFS.

Effects of the lactase 13910 C/T and calcium-sensor receptor A986S G/T gene polymorphisms on the incidence and recurrence of colorectal cancer in Hungarian population.

BackgroundEpidemiological studies suggested the chemopreventive role of higher calcium intake in colorectal carcinogenesis. We examined genetic polymorphisms that might influence calcium metabolism: lactase (LCT) gene 13910 C/T polymorphism causing lactose intolerance and calcium-sensing receptor (CaSR) gene A986S polymorphism as a responsible factor for the altered cellular calcium sensation.Methods538 Hungarian subjects were studied: 278 patients with colorectal cancer and 260 healthy controls. Median follow-up was 17 months. After genotyping, the relationship between LCT 13910 C/T and CaSR A986S polymorphisms as well as tumor incidence/progression was investigated.Resultsin patient with colorectal cancer, a significantly higher LCT CC frequency was associated with increased distant disease recurrence (OR = 4.04; 95% CI = 1.71–9.58; p = 0.006). The disease free survival calculated from distant recurrence was reduced for those with LCT CC genotype (log rank test p = 0.008). In case of CaSR A986S polymorphism, the homozygous SS genotype was more frequent in patients than in controls (OR = 4.01; 95% CI = 1.33–12.07; p = 0.014). The number of LCT C and CaSR S risk alleles were correlated with tumor incidence (p = 0.035). The CCSS genotype combination was found only in patients with CRC (p = 0.033).ConclusionLCT 13910 C/T and CaSR A986S polymorphisms may have an impact on the progression and/or incidence of CRC.

Prognostic Significance of the Thymidylate Biosynthetic Enzymes in Human Colorectal Tumors

The aim of the present study was to determine the relative intratumoral activity of two pyrimidine biosynthetic enzymes, i.e. thymidylate synthase (TS) and thymidine kinase (TK), in human colorectal cancers to compare their possible relationship with demographic and pathologic characteristics of the patients and their tumors, and moreover to evaluate their predictive significance regarding 5-fluorouracil (5-FU) sensitivity and the overall survival of patients, respectively. TS and TK levels were significantly increased in the tumor compared to peritumoral tissue. However, no significant relationship between TS/TK activity and demographic features of the patients or pathologic characteristics of their tumors could be demonstrated. Kaplan-Meier analysis showed that the overall survival of patients with low TS activity was significantly longer (p < 0.012) compared to those with high TS activity. Such a difference could not be demonstrated between patients with high or low TK activity; however, combined evaluation of the two parameters proved that TK may contribute to the more precise assessment of disease prognosis, and it may further influence treatment decisions, i.e. the selection of patients for adjuvant therapy with 5-FU and folinic acid. Multivariate analysis showed that among the variables tested, beside Dukes’ stage, TS and TK activities were significant prognostic factors for the overall survival of colorectal cancer patients.

Microanalytical method development for Fe, Cu and Zn determination in colorectal cancer cells

Microanalytical methods suitable for the determination of Fe, Cu in HT-29 (human colon adenocarcinoma) cells treated with different iron compounds (Fe(II) sulfate, Fe(III) chloride, Fe(III) citrate and Fe(III) transferrin) and cultured in medium supplemented or not with 10% (v/v) fetal calf serum (FCS) by total reflection X-ray fluorescence spectrometry (TXRF) and simultaneous graphite furnace atomic absorption spectrometry (GF-AAS) were developed. The developed TXRF method was also suitable for Zn determination in the samples. The main advantage of the proposed methods is the execution of all sample preparation steps following incubation and prior to the elemental analysis in the same Eppendorf tubes. Sample preparation was performed at microscale (115 μL sample volume) with 65% nitric acid and 30% hydrogen peroxide. According to scanning electron microscopic measurements, the organic matrix of the cell samples could be eliminated to the extent that accurate results were obtained for Cu and Fe by analyzing the same samples by TXRF and GF-AAS. Concerning the iron uptake, HT-29 cells incubated in FCS-free medium contained Fe in cca. 5-50 times higher amounts compared to cells cultured in FCS supplemented medium. Pronounced differences in the iron uptake compared to the iron supply (inorganic vs. organic chelated as well as iron(II) vs. iron(III)) were observed in the case of cell lines incubated in FCS-free medium.

Impact of SHMT1 polymorphism on the clinical outcome of patients with metastatic colorectal cancer treated with first-line FOLFIRI+bevacizumab.

The impact of thymidylate synthase (TYMS), methylenetetrahydrofolate reductase (MTHFR), and serine hydroxymethyltransferase 1 (SHMT1) gene polymorphisms and that of dihydropyrimidine dehydrogenase (DPD) enzyme activity, serum total homocysteine level, and estimated serum creatinine clearance on first-line 5-fluorouracil, leucovorin, irinotecan, and bevacizumab (FOLFIRI+bevacizumab) regimen efficacy in metastatic colorectal cancer patients was investigated. DNA was extracted from peripheral blood mononuclear cells. Genotyping was performed for TYMS 5′UTR variable number tandem repeat, TYMS 3′UTR ins/del, MTHFR C677T, and SHMT1 C1420T polymorphisms. The DPD activity of peripheral blood mononuclear cells was also determined. The univariate and multivariate analyses demonstrated that the SHMT1 1420T allele was associated with better response (P=0.025) and longer progression-free survival (PFS) (P=0.00004) and overall survival (OS) (P=0.034). Grade≥2 hypertension was also an independent prognostic factor of longer progression-free survival and OS. Bevacizumab-related hypertension might be a predictive marker of treatment efficacy (P=0.0002 for OS) in the case of wild (CC) SHMT1 1420 genotypes only.

Increase of hypophyseal hormone levels in male head and neck cancer patients

Head and neck squamous cell carcinoma (HNSCC) develops in at least 80% of cases in men with a history of smoking and heavy alcohol consumption, still it is only diagnosed in a small proportion of alcoholics. Endocrine milieu is an important factor in carcinogenesis and prognosis of several cancer types. The aim of our study was to investigate sex steroid and hypophyseal hormone status of male HNSCC patients in comparison to healthy volunteers and to patients with alcoholic liver disease, to determine possible hormonal alterations characteristic of cancer. Liver function (GGT level), and serum levels of gonadotropic hormones (FSH, LH, prolactin), sex steroids (estradiol, progesterone, testosterone) and sex hormone-binding globulin (SHBG) were compared in 130 male HNSCC patients, 54 patients with alcoholic liver disease but no known cancer, and 56 healthy controls. We found abnormal values of liver function in both HNSCC patients and alcoholics compared to healthy controls, suggesting the presence of alcoholic liver disease in the former group as well. On the other hand, a significant elevation in the level of DHEA, FSH and LH was observed in cancer patients exclusively. As a conclusion, abnormal alterations in sex steroid hormone levels can frequently be found in HNSCC patients, which may be caused in part by the alcoholic liver damage accompanying the disease. The significant increase in FSH and LH serum levels, observed only in the cancer patients, indicates that these hormones may play a role in the development and/or progression of HNSCC.

Early ototoxic changes in patients with germ cell tumor after first cycle of cisplatin-based therapy.

To prospectively examine early hearing damage detectable with distortion product otoacoustic emission (DPOAE) after the first cycle of cisplatin treatment of patients with testicular tumor.

Abiraterone acetate + prednisolone treatment beyond prostate specific antigen and radiographic progression in metastatic castration-resistant prostate cancer patients

OBJECTIVES To investigate the overall survival (OS) of chemotherapy refractory patients with metastatic castration-resistant prostate cancer who were treated with abiraterone acetate + prednisolone (AA + P) beyond prostate specific antigen (PSA) and radiographic progression (PRP) until clinical progression in comparison to patients treated until PRP. METHODS At our institute the AA + P treatment started in 2011 in an early-access protocol trial. In October 2012 AA became generally available. From April 2011 to November 2014, 116 patients received AA + P. The clinical trial patients (T; n = 56) were treated beyond PRP until clinical progression. In the nonclinical trial group (NT; n = 57) the treatment was covered until PRP. Three patients are still under treatment. The 2 groups were statistically homogeneous, except AA + P treatment duration. The primary objective was the OS and the secondary the PSA progression-free and radiographic progression-free survivals. RESULTS The median OS was significantly longer (P<0.0001) in the T group compared to the NT group: 21.9 (95% CI: 16.9-25) vs. 12.5 (9.3-14.1) months, respectively. In univariate analysis there were 11 parameters, which significantly affected OS, but in multivariate Cox analysis only alkaline phosphatase (AP) level at the start of treatment, systemic therapy after AA + P and cohort type (T or NT) proved to independently influence the OS. The progression-free survival curves of T and NT groups did not differ significantly. CONCLUSIONS In our retrospective analysis low levels of AP at the start of treatment, systemic therapy applied after AA + P and treatment beyond PRP proved to be independent factors of longer OS in metastatic castration-resistant prostate cancer.