Agnieszka Jeleń

The Influence of C3435T Polymorphism of the ABCB1 Gene on Genetic Susceptibility to Depression and Treatment Response in Polish Population - Preliminary Report.

Background: Despite the high prevalence of depression, the mechanism of the origin of this disease as well as the causes of resistance to therapy in some patients are still not fully understood. Increasingly, the possible role of genetic factors is considered. One of them is polymorphisms in the ABCB1 (MDR1) gene which encodes P-glycoprotein, responsible for the transport of xenobiotics, including antidepressant drugs, through the blood-brain barrier. Methods: C3435T was evaluated in 90 patients with recurrent depressive disorders (rDD). Genotyping was performed using a polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Results: The obtained results indicate that the TT genotype occurred more frequently among patients with rDD than in healthy volunteers (p=0.0441). Also, at least one C allele was present significantly less frequent in the study group than in healthy individuals (p=0.0300). The severity of depressive symptoms was higher among patient with the CC genotype in comparison with the other genotypes (p=0.0106) but treatment response to antidepressants was better in this group than among patients with CT or TT genotypes (p=0.0301). Likewise, patients with the T allele have a significantly lower severity of symptoms (p=0.0026) and decreased therapy effectiveness (p=0.0142) than C allele carriers. Conclusions: This study suggests that C3435T polymorphisms in the ABCB1 gene are strongly associated with a predisposition to depression development, the severity of depressive symptoms and the effectiveness of therapy with using different groups of antidepressant agents.

Investigation of -308G>A and -1031T>C polymorphisms in the TNFA promoter region in Polish peptic ulcer patients.

Background/Aims Tumor necrosis factor α (TNF-α) encoded by TNFA is a key mediator in inflammation, a precursor condition for peptic ulceration. Promoter polymorphisms of TNFA that influence its transcriptional activity and TNF-α production are known. TNFA-308G>A (rs1800629) and TNFA-1031T>C (rs1799964), which are responsible for increased TNFA transcription, could influence the risk of peptic ulceration. This study aimed to investigate these polymorphisms and to evaluate their association with peptic ulcer disease and Helicobacter pylori infection in the Polish population. Methods Gastric mucosa specimens obtained from 177 Polish peptic ulcer patients were used to conduct rapid urease tests and to assess the investigated polymorphisms by polymerase chain reaction-restriction fragment length polymorphism. Genotyping data were compared with the results obtained from healthy individuals of Polish origin. Results There were no significant differences in genotype and allele frequency of the investigated polymorphisms between peptic ulcer patients and healthy individuals. No associations between the frequencies of particular genotypes and alleles for both single-nucleotide polymorphisms (SNPs) and the presence of H. pylori infection in peptic ulcer patients and in subgroups of men and women with peptic ulcer disease were found. Conclusions The investigated SNPs are not risk factors for either peptic ulcer or H. pylori infection development in the Polish population. The results require verification in a larger cohort.

Haplotype Analysis of TNFA Gene in Peptic Ulcer Patients

Abstract The TNFA gene product TNF-? is a cytokine promoting an immune response after bacterial infections. An excessive production of the cytokine is thought to be connected with Helicobacter pylori-induced disorders like gastritis, peptic ulcer disease (PUD), intestinal metaplasia, or even gastric cancer. The synthesis of TNF-á is controlled at transcriptional level and dependent on single nucleotide polymorphisms (SNPs) of TNFA promoter region. SNPs assembled in haplotype have been implicated as potential risk factors for various autoimmune and infectious diseases. The aim of this study was to determine the frequencies of TNFA haplotypes composed of the four common single-nucleotide polymorphisms of the gene (-1031C>T: rs1799964, -863C>A: rs1800630, - 857C>T: rs1799724, -308G>A: rs1800629) in peptic ulcer patients and to assess the significance of the haplotypes as the risk factors of H. pylori infection development. 203 peptic ulcer patients were genotyped using polymerase chain reaction-restriction fragment length polymorphism method. Haplotypes and degree of linkage disequilibrium (LD) were inferred with PHASE 2.1 and EMLD software. There was no statistically significant difference in haplotype frequencies between the H. pylori-infected and-uninfected peptic ulcer cases (p=0.62). Analogous association was also absent in the subgroups: peptic ulcer woman (p=0.69), peptic ulcer men (p=0.17). The locus pairs -308_-857, -863_-1031, and -857_-1031 was found to be in very strong L¯D , -308_-1031 and -857 and -863 in strong LD, and -308_-863 - in modest LD. TNFA haplotype structure is not connected with individual differences in susceptibility to development of H. pylori infection in peptic ulcer patients.

Is the ABCB1 gene associated with the increased risk of gastric cancer development?--preliminary research.

One of the most common malignant diseases, both worldwide and in Poland, is gastric cancer. The pathogenesis of gastric cancer development is not entirely clear. Next to the environmental risk factors, such as Helicobacter pylori infection or dietary habits, the host genetic factors as predispositions to gastric cancer development are discussed. A transmembrane protein that could be associated with predisposition to cancer development is P-glycoprotein (P-gp). Physiologically, P-gp is present in normal tissue of the gastrointestinal tract, where it plays a protective role by transporting xenobiotics from a cell into extracellular environment. P-gp is encoded by the highly polymorphic ABCB1 gene. The most frequent polymorphisms at positions 1236, 2677, and 3435 may affect both the function and amount of protein, thereby leading to a loss of its physiological function, which could increase the predisposition to development of many diseases, including cancer. In this study, the potential significance of the ABCB1 gene in the development and progression of gastric cancer was evaluated. In 19 tissue samples collected from patients with gastric cancer, the ABCB1 gene polymorphisms were identified at positions 1236 and 2677 by automated sequencing and SNP 3435 by the RFLP method. The relative level of ABCB1 expression was measured in 10 samples of gastric cancer and morphologically normal tissues by real-time PCR. For SNPs at positions 1236, 2677, and 3435, no statistically significant differences in genotype frequencies between gastric cancer patients and healthy individuals were found. However, genotype TT for all studied polymorphisms occurred more frequently in the group of gastric cancer patients (31.6, 26.3, 42.1%, respectively) than in the group of healthy individuals (14.6, 13.5, 21.9%, respectively). The lowest relative expression levels of ABCB1 mRNA were observed for genotypes CC of SNP 1236, CC of SNP 3435, and GG of SNP 2677 (median: 0.215, 0.160, 0.160, respectively). There was a tendency that mutant homozygote TT for SNPs at positions 1236, 2677, and 3435 occurred more frequently in the subgroup of patients with Tis or stage I of TNM classification (SNP 1236 p = 0.0760; SNP 2677 p = 0.0813; SNP 3435 p = 0.0760) than in the subgroup of patients with stage II or III. Also the expression levels were lowest (median 0.740) in the group of patients with the less advanced clinical stage of cancer (Tis or I). Preliminary research showed that the ABCB1 gene polymorphisms at positions 1236, 2677, and 3435 were not related to an increased susceptibility of gastric cancer development. However, they may be associated with the inhibition of gastric cancer progression.

BQ123 Stimulates Skeletal Muscle Antioxidant Defense via Nrf2 Activation in LPS-Treated Rats

Little is understood of skeletal muscle tissue in terms of oxidative stress and inflammation. Endothelin-1 is an endogenous, vasoconstrictive peptide which can induce overproduction of reactive oxygen species and proinflammatory cytokines. The aim of this study was to evaluate whether BQ123, an endothelin-A receptor antagonist, influences the level of TNF-α, IL-6, SOD-1, HO-1, Nrf2 mRNA, and NF-κB subunit RelA/p65 mRNA in the femoral muscle obtained from endotoxemic rats. Male Wistar rats were divided into 4 groups (n = 6) and received iv (1) saline (control), (2) LPS (15 mg/kg), (3) BQ123 (1 mg/kg), (4) BQ123 (1 mg/kg), and LPS (15 mg/kg, resp.) 30 min later. Injection of LPS led to significant increase in levels of RelA/p65 mRNA, TNF-α, and IL-6, while content of SOD-1, HO-1, and Nrf2 mRNA was unchanged. Administration of BQ123 prior to LPS challenge resulted in a significant reduction in RelA/p65 mRNA, TNF-α, and IL-6 levels, as well as markedly elevated concentrations of SOD-1, HO-1, and Nrf2 mRNA. BQ123 appears to enhance antioxidant defense and prevent production of TNF-α and IL-6 in skeletal muscle of LPS-treated rat. In conclusion, endothelin-A receptor antagonism exerts significant impact on the skeletal muscle favouring anti-inflammatory effects and protection against oxidative stress.

Assessment of TNFA polymorphisms at positions -857 and -863 in Polish peptic ulcer patients.

PURPOSE Peptic ulceration connected with chronic inflammation in gastrointestinal mucosa could be induced by Helicobacter pylori infection. Tumor necrosis factor alpha (TNF-α) encoded by TNFA gene is a key mediator in the inflammation process. There are several polymorphisms in the promoter of TNFA influencing its transcriptional activity. -857C>T (rs1799724) and -863C>A (rs1800630) substitutions may be responsible for increased TNFA transcription and TNF-α production. The association of these two polymorphisms with peptic ulceration and the development of H. pylori infection in peptic ulcer patients in Poles were evaluated. MATERIAL AND METHODS Polymorphisms were assessed by PCR-RFLP in 203 peptic ulcer patients. H. pylori infection was confirmed by rapid urease test. The results of genotyping were compared with those obtained for 248 healthy Polish individuals. RESULTS There were no significant differences in genotype and allele frequencies for both investigated polymorphisms between peptic ulcer patients and healthy individuals. No associations between frequencies of particular genotypes and alleles for both SNPs and the presence of H. pylori infection in peptic ulcer patients and in subgroups of peptic ulcer women and men were confirmed. CONCLUSIONS The investigated SNPs are not risk factors for peptic ulcer development. They are not risk factors for H. pylori infection in ulcer patients.

Quantitative analysis of FJ 194940.1 gene expression in colon cancer and its association with clinicopathological parameters

Aim of the study The FJ 194940.1 gene is located on chromosome 1 and consists of 6 exons and 5 introns. The gene undergoes alternative splicing and its isoforms appear during cancer development. Evidence suggests that expression of FJ 194940.1 splice variants relate to colorectal cancer progression. This paper discusses the quantitative analysis of the exon V expression level of FJ 194940.1 in colon cancer. The aim of the study is to carry out quantitative analysis by real-time PCR in a series of 102 colon cancer samples that had previously shown presence of exon V expression. To compare the exon V expression level with certain histological parameters and clinical staging of the neoplasm in order to assess its potential role as a prognostic factor in colon cancer. Material and methods Tissue specimens of colorectal cancer were obtained from the Oncological Centre of Lodz, Poland.Total RNA isolation was performed in accordance with the protocol enclosed in the Total RNA Prep Plus Minicolumn Kit (A&A Biotechnology, Poland). Reverse Transcriptase-PCR reaction was carried out using Enhanced Avian HSRT-PCR Kit, Sigma, according to the manufacturers protocol.. Presence of cDNA in each sample was checked by PCR amplification of β-actin. Only samples showing the PCR product of this housekeeping gene were included in further tests. The amount of FJ 194940.1 transcript containing exon V was analysed by means of real-time PCR. Results Exon V expression level is not significantly related to any clinicopathological features in colon cancer. However, there was a tendency towards a lower exon V expression level in a group of cases where vessel invasion was present (p = 0.0697). Additionally, the risk of death in patients with a low exon V expression level was more than two times higher when compared to patients with a high exon V expression level. Conclusions FJ 194940.1 gene expression correlates with cancer progression independently of analysed clinicopathological parameters.

Expression levels of the runt-related transcription factor 1 and 3 genes in the development of acute myeloid leukemia

The aim of the present study was to evaluate the mRNA expression level of the runt-related transcription factor 1 (RUNX1) and runt-related transcription factor 3 (RUNX3) genes in patients with acute myeloid leukemia (AML). The etiology of AML is not yet fully known, but certain genetic factors may contribute to its manifestation. The RUNX1 and RUNX3 genes have been demonstrated to serve a role in the transcription process. The group investigated in the present study included 43 patients diagnosed with AML, and the relative RUNX1 and RUNX3 expression levels were determined using reverse transcription-quantitative polymerase chain reaction. The results indicated that RUNX1 and RUNX3 expression was associated with clinicopathological features, including sex and mortality risk. Expression levels of the RUNX1 gene were higher and more variable among females (P=0.044), and mortality was more frequent among patients with a higher RUNX3 expression level (P=0.036). The data obtained from the present study suggested that RUNX3 expression may have potential value as a prognostic factor; furthermore, sex is potentially a factor that may affect the difference in RUNX1 gene expression level among females and males. Further analyses in this field will aid in the identification and elucidation of the molecular basis of leukemia.

Characterisation of selected molecular mechanisms influencing pharmacokinetics and pharmacodynamics of antidepressants

Over 350 millions of people suffer from depression worldwide, and an increase in the incidence of the disease is expected in the coming years. Therefore, there is a strong need of knowing the mechanisms of development this disease and its effective treatment. Pharmacological therapy is an essential element of antidepressant therapy and its failure is a serious problem in clinical psychiatry. In spite of large number of available medicines, only 50% of patients achieved remission after single-drug treatment. Genetic factors which predispose to depression development and predict an outcome of its pharmacotherapy, probably play a substantial role in these phenomena. In spite of this, they are still not characterized enough and applied in practice. Therefore, the aim of this study is to present the current knowledge of the impact of selected genes on pharmacokinetics and pharmacodynamics of antidepressants by changing function and/or structure of encoded proteins. In the review the best known polymorphisms of selected genes encoding isoenzymes of cytochrome P-450, responsible for metabolism of popular antidepressant drugs, namely CYP2C19, CYP2D6, CYP1A2, and CYP3A4/5 are described. Further, 4 polymorphisms of ABCB1 gene (rs 1045642, rs 2032582, rs 1128503 and rs 2032583) encoding glycoprotein P, which play a key role in transportation of large number of drugs used in treatment of depression. For benefit of treatment of patients with depression, it is worthy to estimate and to take on the board all so far known mechanisms of planning therapy.