Katja Goričar

Genetic variability of DNA repair mechanisms and glutathione-S-transferase genes influences treatment outcome in osteosarcoma.

BACKGROUND Osteosarcoma patients are commonly treated with cisplatin-based preoperative and postoperative chemotherapy. Cisplatin binds to DNA and forms both intrastrand and interstrand crosslinks, inhibiting DNA replication. Glutathione-S-transferases (GSTs) participate in cisplatin detoxification, while several independent DNA repair mechanisms repair cisplatin-induced lesions. The aim of our study was to investigate the influence of genetic variability of DNA repair mechanisms and GSTs on efficacy and toxicity of cisplatin-based chemotherapy in osteosarcoma patients. METHODS A total of 66 osteosarcoma patients were genotyped for ERCC1, ERCC2, NBN, RAD51, XRCC3, and GSTP1 polymorphisms, as well as GSTM1 and GSTT1 gene deletion. We determined the influence of polymorphisms on survival and treatment outcome using Cox regression and logistic regression. RESULTS Carriers of at least one polymorphic ERCC2 rs1799793 allele had longer event-free survival (EFS) (P=0.006; hazard ratio (HR)=0.28; 95% confidence interval (CI)=0.11-0.70). Polymorphic GSTP1 rs1138272 allele was associated with both shorter EFS and OS (P=0.005; HR=3.67; 95%CI=1.47-9.16; and P=0.004; HR=3.52; 95%CI=1.51-8.22, respectively). Compared to the reference NBN CAA haplotype, NBN CGA haplotype was associated with shorter EFS (P=0.001; HR=4.12; 95%CI=1.77-9.56). CONCLUSIONS Our results suggest that DNA repair polymorphisms and GST polymorphisms could be used as predictive factors for cisplatin-based chemotherapy in osteosarcoma patients and could contribute to treatment personalization.

Association of SOD2 , GPX1 , CAT , and TNF Genetic Polymorphisms with Oxidative Stress, Neurochemistry, Psychopathology, and Extrapyramidal Symptoms in Schizophrenia

There is a growing body of evidence confirming the involvement of oxidative stress and inflammation in pathogenesis of schizophrenia. Inter-individual variation in antioxidant capacity caused by different genetic profile could potentially influence patient’s susceptibility to oxidative damage. In this study we evaluated the polymorphisms of manganese superoxide dismutase SOD2Val16Ala, glutathione peroxidase GPX1Pro200Leu, catalase CAT-262C>T and CATc.66+78C>T, and tumour necrosis factor-alpha TNF-308G>A by assessing their association with biomarkers of oxidative stress, neurochemistry, psychopathology of schizophrenia and extrapyramidal symptoms in Caucasian schizophrenia patients treated with haloperidol depot. TNF-308G>A was associated with the increased risk of parkinsonism. No major role of polymorphism of SOD2Val16Ala, CAT-262C>T nor GPX1Pro200Leu in psychopathology of schizophrenia or extrapyramidal symptoms was observed. SOD2Val16Ala polymorphism was associated with dopamine plasma concentration and blood concentration ratio between reduced and oxidised form of glutathione, while GPX1Pro200Leu was related with concentration of reduced glutathione. CATc.66+78C>T was associated with noradrenaline plasma concentration and PANSS negative score. PANSS positive and general scores, were associated with the increased risk of tardive dyskinesia. PANSS positive, negative, and general scores, and GAF score were all associated with the increased risk of akathisia.

Genetic polymorphisms in homologous recombination repair genes in healthy Slovenian population and their influence on DNA damage.

Genetic polymorphisms in homologous recombination repair genes in healthy Slovenian population and their influence on DNA damage Background. Homologous recombination (HR) repair is an important mechanism involved in repairing double-strand breaks in DNA and for maintaining genomic stability. Polymorphisms in genes coding for enzymes involved in this pathway may influence the capacity for DNA repair. The aim of this study was to select tag single nucleotide polymorphisms (SNPs) in specific genes involved in HR repair, to determine their allele frequencies in a healthy Slovenian population and their influence on DNA damage detected with comet assay. Materials and methods. In total 373 individuals were genotyped for nine tag SNPs in three genes: XRCC3 722C>T, XRCC3 -316A>G, RAD51 -98G>C, RAD51 -61G>T, RAD51 1522T>G, NBS1 553G>C, NBS1 1197A>G, NBS1 37117C>T and NBS1 3474A>C using competitive allele-specific amplification (KASPar assay). Comet assay was performed in a subgroup of 26 individuals to determine the influence of selected SNPs on DNA damage. Results. We observed that age significantly affected genotype frequencies distribution of XRCC3 -316A>G (P = 0.039) in healthy male blood donors. XRCC3 722C>T (P = 0.005), RAD51 -61G>T (P = 0.023) and NBS1 553G>C (P = 0.008) had a statistically significant influence on DNA damage. Conclusions.XRCC3 722C>T, RAD51 -61G>T and NBS1 553G>C polymorphisms significantly affect the repair of damaged DNA and may be of clinical importance as they are common in Slovenian population.

NLRP3 Inflammasome Polymorphism and Macrovascular Complications in Type 2 Diabetes Patients

Background. It is generally accepted that poor glycemic control, arterial hypertension and/or hyperlipidemia, and the associated oxidative stress may contribute to the development of macro- and microvascular complications in type 2 diabetes (T2D). Such metabolic damage signals may activate inflammasome and trigger chronic inflammation. We investigated common polymorphisms in inflammasome coding genes and the risk for macro- and microvascular complications in T2D. Methods. In total 181 clinically well-characterised T2D patients were genotyped for NLRP3 rs35829419 and CARD8 rs2043211. Risk for diabetic complications was assessed using logistic regression. Results. Patients with median duration of T2D 11 (6–17) years had relatively well controlled blood glucose and lipid levels and blood pressure on the prescribed treatment regimen. Duration of T2D and plasma cholesterol levels were the most important clinical risk factors for macrovascular complications (P = 0.007 and P = 0.031). NLRP3 rs35829419 was associated with increased risk for macrovascular complications (P = 0.004), with myocardial infarction in particular (P = 0.052). No association was observed between CARD8 polymorphism and any of T2D complications. Conclusions. Our preliminary data suggest the role of NLRP3 polymorphism in diabetic macrovascular complications, especially in myocardial infarction.

Metformin as an initial adjunct to low-dose liraglutide enhances the weight-decreasing potential of liraglutide in obese polycystic ovary syndrome: Randomized control study

Liraglutide (LIRA) treatment is associated with the dose-dependent reduction of weight. Higher doses are more effective than lower doses, although higher doses are also more poorly tolerated. Metformin may enhance the weight-lowering potential of LIRA via the stimulatory modulation of incretin in addition to its direct beneficial effects in PCOS. The aim of the present study was to evaluate whether metformin as an adjunct to low-dose LIRA affects body weight with increased efficacy compared with low-dose LIRA alone in obese patients with PCOS. In a 12-week study, 44 obese women with PCOS were randomly offered either combined treatment (COMBO) with 1,000 mg metformin twice a day and 1.2 mg LIRA once a day, or treatment with 1.2 mg LIRA alone. The primary outcome of treatment was an alteration in the levels of obesity. A total of 43 patients [aged 30.3±4.4 years; body mass index (BMI) 37.2±4.5 kg/m2; mean ± standard deviation] completed the study. The subjects treated with COMBO lost on average 6.2±2.4 kg compared with a 3.8±3.5 kg weight loss in the patients treated with LIRA alone (P=0.024). The BMI decreased by 2.2±0.8 kg/m2 in patients treated with COMBO and by 1.4±1.2 kg/m2 in patients treated with LIRA alone (P=0.024). A clinically significant ≥5% weight reduction was achieved in 59.1% of patients treated with COMBO and 42.9% of patients treated with LIRA alone. Reductions in glucose levels following oral glucose tolerance testing, as well as in androstenedione levels in the COMBO group were significantly greater compared with those in the LIRA group. The side effects were mild and transient in the two treatment groups. A combination of metformin and low-dose LIRA was more effective than low-dose LIRA alone in reducing body weight in obese patients with PCOS.

Polymorphisms in folate pathway and pemetrexed treatment outcome in patients with malignant pleural mesothelioma

Abstract Introduction. A combination of pemetrexed and cisplatin has been shown to improve the outcome in patients with malignant pleural mesothelioma (MPM), however, there is a great heterogeneity in treatment response among patients. The aim of our study was to evaluate the influence of polymorphisms in folate pathway and transporter genes on pemetrexed treatment outcome in Slovenian patients with MPM. Methods. MPM patients treated with pemetrexed in the course of a prospective randomized clinical trial were genotyped for nineteen polymorphisms in five genes of folate pathway and six transporter genes. Logistic regression was used to assess the influence of polymorphisms on treatment efficacy and toxicity, while Cox regression was used to determine their influence on progression-free and overall survival. Results. Patients with at least one polymorphic MTHFD1 rs2236225 allele had a significantly lower response rate (p = 0.005; odds ratio [OR] = 0.12; 95% confidence interval [CI] = 0.03−0.54) and shorter progression-free survival (p = 0.032; hazard ratio [HR] = 3.10; 95% CI = 1.10−8.74) than non-carriers. Polymorphisms in transporter genes did not influence survival; however, several were associated with toxicity. Liver toxicity was significantly lower in carriers of polymorphic ABCC2 rs2273697 (p = 0.028; OR = 0.23; 95% CI = 0.06−0.85), SLCO1B1 rs4149056 (p = 0.028; OR = 0.23; 95% CI = 0.06−0.85) and rs11045879 (p = 0.014; OR = 0.18; 95% CI = 0.05−0.71) alleles compared to non-carriers, as well as in patients with SLCO1B1 GCAC haplotype (p = 0.048; OR = 0.17; 95% CI = 0.03−0.98). Gastrointestinal toxicity was much more common in patients with polymorphic ABCC2 rs717620 allele (p = 0.004; OR = 10.67; 95% CI = 2.15−52.85) and ABCC2 CAG haplotype (p = 0.006; OR = 5.67; 95% CI = 1.64−19.66). Conclusions. MTHFD1 polymorphism affected treatment response and survival, while polymorphisms in ABCC2 and SLCO1B1 transporter genes influenced the risk for toxicity. These polymorphisms could serve as potential markers of pemetrexed treatment outcome in patients with MPM.

Polymorphisms in GRIA1 gene are a risk factor for asparaginase hypersensitivity during the treatment of childhood acute lymphoblastic leukemia.

l-asparaginase is an effective antineoplastic agent used in chemotherapy of acute lymphoblastic leukemia. The drug effect may be compromised by an elicited immune response, resulting in the production of anti-asparaginase antibodies causing an anaphylactic reaction or silent inactivation of the enzyme. To elucidate possible genetic predisposition for inter-individual differences in asparaginase hypersensitivity, we studied single nucleotide polymorphisms (SNPs) in the GRIA1 gene in 146 pediatric patients treated with l-asparaginase. Allergic reaction to l-asparaginase occurred in 49.3% of patients. We observed a statistically significant association between SNPs in the GRIA1 gene and the occurrence of asparaginase allergy: rs4958351 with p = 0.003, rs4958676 with p = 0.005, rs6889909 with p = 0.005, rs6890057 with p = 0.005 and rs10070447 with p = 0.006. We found a statistically significant correlation between asparaginase allergy and event-free survival (p-value 0.005).

The Role of Genetic Factors and Kidney and Liver Function in Glycemic Control in Type 2 Diabetes Patients on Long-Term Metformin and Sulphonylurea Cotreatment

This study investigated the influence of genetic polymorphisms of metformin transporters on long-term glycemic control and lipid status in type 2 diabetes patients in the everyday clinical setting. In total 135 patients treated with combination of metformin and sulphonylurea for at least 6 months were genotyped for SLC22A1 rs628031 and SLC47A1 rs2289669 polymorphisms. Relatively good blood glucose control with median HbA1c 6.9 (6.4–7.6) % was achieved on prescribed metformin dosage of 2550 (2000–2550) mg per day. Only 28 (20.7%) patients experienced mild hypoglycemia events, while no severe hypoglycemia events were observed. Most patients had normal or mildly impaired renal function. Parameters indicating renal function were not correlated with fasting glucose, HbA1c, or lipid parameters. Rs628031 and rs2289669 had minor allele frequencies of 0.385 and 0.355, respectively, and were not associated with HbA1c levels. Rs628031 was marginally associated with risk for hypoglycemia events (P = 0.046; OR = 0.51; 95% CI 0.26–0.99), while significant correlation was observed between rs2289669 and total cholesterol levels (P = 0.018). In conclusion, in patients on long-term metformin and sulphonylurea combination treatment, metformin transporters polymorphisms do not play a major role in glycemic control; however, they may influence lipid status.

Polymorphisms in translesion polymerase genes influence treatment outcome in malignant mesothelioma

AIM We evaluated the influence of genetic variability in translesion polymerases REV1 and REV3L on the outcome of cisplatin treatment in malignant mesothelioma patients. MATERIALS & METHODS In total, 139 malignant mesothelioma patients were genotyped for seven tag SNPs in REV1 and REV3L. Logistic regression and Cox regression were used to assess the influence of SNPs on treatment outcome. RESULTS Polymorphic REV1 rs3087403 allele and REV1 TGT haplotype were associated with increased risk for leukopenia (p = 0.013 and p = 0.047, respectively) and neutropenia (p = 0.048 and p = 0.024, respectively). REV3L rs465646, rs462779 and REV3L CCGG haplotype were significantly associated with longer overall survival (p = 0.007, p = 0.022 and p = 0.013, respectively). CONCLUSION Our results suggest for the first time that REV1 and REV3L SNPs might serve as potential predictive markers of outcome of cisplatin-based chemotherapy. Original submitted 7 October 2013; Revision submitted 15 January 2014.

Add on DPP-4 inhibitor alogliptin alone or in combination with pioglitazone improved β-cell function and insulin sensitivity in metformin treated PCOS

ABSTRACT Purpose: Impaired β-cell function remains unaddressed in PCOS. The aim of the study was to evaluate whether dipeptidyl peptidase-4 (DPP-4) inhibitor alogliptin (ALO) alone or in combination with pioglitazone (PIO) improves β-cell function along with insulin resistance (IR) in metformin (MET) treated obese women with PCOS with persistent IR. Materials and methods: In 12-week randomized study, ALO 25 mg QD (n=15) or ALO 25 mg QD and PIO 30 mg QD (n=15) was added to MET 1000 mg BID in PCOS women (aged 34.4 ± 6.5 years, BMI 39.0 ± 4.9 kg/m2, HOMA-IR 4.82 ± 2.52, mean ± SD). Model derived parameters of glucose homeostasis from the meal tolerance test (MTT) were determined. The ability of the β-cell function was assessed by the adaptation index (AI). Results: MET-ALO and MET-ALO-PIO resulted in a significant decrease of HOMA-IR (by 1.6±2.3 (p=0.039) and 2.9±3.3 (p=0.001), respectively) and an increase in insulin sensitivity (IS) after meal ingestion (oral glucose IS) by 31.4±97.5 ml·min–1·m–2 (p=0.007) vs 39.0±58.1 ml·min–1·m–2 (p=0.039), respectively. AI across the entire group was significantly improved from 329.6±200.6 to 442.5±303.9 (p=0.048). Conclusions: ALO alone and in combination with PIO improved IR along with dynamic IS and meal related β-cell function when added to MET treated PCOS.