Bedia Cakmakoglu

Association of APE1 and hOGG1 polymorphisms with colorectal cancer risk in a Turkish population

Abstract Background: There is growing evidence describing DNA repair genes polymorphisms are related to increased cancer risk including colorectal cancer (CRC). The aim of this study was to investigate the associations between the APE1 Asp148Glu, hOGG1 Ser326Cys, XRCC1 Arg399Gln, XRCC3 Thr241Met, XPD Lys751Gln, XPG Asp1104His polymorphisms and CRC risk in Turkish population. Patients and methods: Polymorphisms of APE1 Asp148Glu (rs3136820), hOGG1 Ser326Cys (rs1052133), XRCC1 Arg399Gln(rs25487), XRCC3 Thr241Met (rs861539), XPD Lys751Gln (rs13181), and XPG Asp1104His (rs17655) were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods in blood samples of 79 CRC patients at their initial staging and 247 healthy controls. Of the CRC patients, 26 out of 40 were diagnosed with rectal cancer and received neoadjuvant chemoradiotherapy following diagnosis; 39 others were diagnosed as colon cancer. Results: Our preliminary results showed that frequencies of Glu allele of APE1 Asp148Glu and Cys allele of hOGG1 Ser326Cys were higher in CRC patients than in controls (p = 0.006, OR: 3.43; 95% CI: 1.76–6.70; p = 0.000, OR: 2.77; 95% CI: 1.40–5.48, respectively). Higher frequency of Met allele of XRCC3 Thr241Met was detected in patients treated with neoadjuvant chemoradiotherapy (p = 0.024, OR: 5.25; 95% CI: 1.23–23.39) and with proximal colon tumors (p = 0.04, OR: 2; 95% CI: 1.18–3.34). Increased frequency of Ser/Ser genotype of hOGG1 Ser326Cys was found to be associated both with higher grade (p = 0.001, OR: 6.4; 95% CI: 2.69–62.69) and liver metastasis (p = 0.005, OR: 7.5; 95% CI: 0.7–68.36). Conclusion: APE1 Asp148Glu and hOGG1 Ser326Cys polymorphisms might be associated with increasing risk of CRC in a Turkish population. Future studies with larger-sized samples, as well as detecting the association of DNA repair genes with other confounding factors will help elucidate the exact roles of DNA repair genes polymorphisms in development and progression of CRC.

DNA Repair Genes in Parkinson's Disease

AIMS There is a growing interest in the understanding of a possible role of DNA repair systems in ageing and neurodegenerative diseases after DNA damage is observed in the brain of individuals affected by neurodegenerative diseases. In the light of these findings, we investigated whether DNA repair gene polymorphisms (XRCC1 Arg399Gln, XRCC3 Thr241Met XPD Lys751Gln, XPG Asp1104His, APE1 Asp148Glu, and HOGG1 Ser326Cys) account for an increased risk of Parkinsons disease (PD). METHODS The present analyses are based on 60 case subjects with PD and 108 unrelated healthy controls. Genotyping of DNA repair gene polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism. RESULTS We, for the first time, demonstrated the positive association of APE1, XRCC1, and XRCC3 DNA repair gene variants with PD risk. In our study, the frequencies of Glu/Glu genotype in APE1, Gln+ genotype of XRCC1, and Thr+ genotype of XRCC3 are higher in patients than in controls (p=0.028, p=0.002 and p=0.046, respectively). CONCLUSIONS In conclusion, our findings have suggested that APE1, XRCC1, and XRCC3 genetic variants may be a risk factor by increasing oxidative stress that might cause the loss of dopaminergic cells in the substantiata nigra and locus caeruleus, leading to abnormal signal transmittion, and ultimately, the development of PD. In addition, generation of reactive oxygen species from dopamine might affect the other DNA repair pathway proteins that we did not examine in the current study. Further studies with larger sample groups are necessary to clarify the role of DNA repair genes and the development of PD.

Anti-proliferative, apoptotic and signal transduction effects of hesperidin in non-small cell lung cancer cells

PurposeHesperidin, a glycoside flavonoid, is thought to act as an anti-cancer agent, since it has been found to exhibit both pro-apoptotic and anti-proliferative effects in several cancer cell types. The mechanisms underlying hesperidin-induced growth arrest and apoptosis are, however, not well understood. Here, we aimed to investigate the anti-proliferative and apoptotic effects of hesperidin on non-small cell lung cancer (NSCLC) cells and to investigate the mechanisms involved.MethodsThe anti-proliferative and apoptotic effects of hesperidin on two NSCLC-derived cell lines, A549 and NCI-H358, were determined using a WST-1 colorimetric assay, a LDH cytotoxicity assay, a Cell Death Detection assay, an AnnexinV-FITC assay, a caspase-3 assay and a JC-1 assay, respectively, all in a time- and dose-dependent manner. As a control, non-cancerous MRC-5 lung fibroblasts were included. Changes in whole genome gene expression profiles were assessed using an Illumina Human HT-12v4 beadchip microarray platform, and subsequent data analyses were performed using an Illumina Genome Studio and Ingenuity Pathway Analyser (IPA).ResultsWe found that after hesperidin treatment, A549 and NCI-H358 cells exhibited decreasing cell proliferation and increasing caspase-3 and other apoptosis-related activities, in conjunction with decreasing mitochondrial membrane potential activities, in a dose- and time-dependent manner. Through a GO analysis, by which changes in gene expression profiles were compared, we found that the FGF and NF-κB signal transduction pathways were most significantly affected in the hesperidin treated NCI-H358 and A549 NSCLC cells.ConclusionsOur results indicate that hesperidin elicits an in vitro growth inhibitory effect on NSCLC cells by modulating immune response-related pathways that affect apoptosis. When confirmed in vivo, hesperidin may serve as a novel anti-proliferative agent for non-small cell lung cancer.

Association of polymorphisms in MCP-1, CCR2, and CCR5 genes with the risk and clinicopathological characteristics of prostate cancer.

The aim of our study was to determine the effect of monocyte chemotactic protein-1 (MCP-1), CC chemokine receptor 2 (CCR2), and CC chemokine receptor 5 (CCR5) gene polymorphisms on the susceptibility and clinicopathological characteristics of prostate cancer. Genotyping was performed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method in 156 histopathologically confirmed prostate cancer patients and 152 healthy subjects. Individuals with AA genotype or at least one A allele of CCR2 V64I gene polymorphism had a higher risk for prostate cancer as compared with those with GG genotype (p=0.010 and p=0.028, respectively). CCR5 Δ32/wt genotype and CCR5 Δ32 allele were also found to be involved in the susceptibility to prostate cancer (p=0.028 and p=0.030, respectively). However, there was no significant association between MCP-1-2518 A/G gene polymorphism and prostate cancer risk. Prostate cancer patients carrying AA genotype or at least one A allele of CCR2 V64I had significantly increased risk for high stage disease (p=0.002 and p=0.039, respectively) and metastasis (p=0.004 and p=0.022, respectively). The CCR2 A allele (64I allele) was significantly associated with high T stage (p=0.001) and metastasis (p=0.005) as compared with CCR2 G allele (64V allele). Our data indicate that gene polymorphism of CCR2 V64I may influence the susceptibility and clinicopathological characteristics of prostate cancer and CCR5 Δ32 allele may also be an important risk factor for prostate cancer in Turkish men population.

Association Between Polymorphisms of DNA Repair Genes and Risk of Schizophrenia

AIMS DNA repair gene polymorphisms have recently been implicated as potential pathogenic contributors of mental disorders. The aims of our study were to investigate the participation of nucleotide and base excision repair mechanisms in schizophrenia and to identify novel candidate DNA repair susceptibility genes. MATERIALS AND METHODS For these purposes, we genotyped apurinic/apyrimidinic endonuclease 1 (APE1), human 8-oxoguanine DNA N-glycosylase 1 (hOGG1), X-ray repair cross-complementation group 1 (XRCC1), XRCC3, xeroderma pigmentosum group D (XPD), and xeroderma pigmentosum group G (XPG) genes in schizophrenia subjects, their healthy relatives, and unrelated healthy controls. RESULTS Carriers of XRCC1 glutamine (Gln), XRCC3 threonine (Thr), hOGG1 cysteine (Cys), and XPD lysine (Lys) alleles were significantly more frequent among the cohort of schizophrenia patients than in controls. In contrast, the frequencies of XRCC3 methionine (Met) and XPD Gln allele carriers and hOGG1 serine (Ser)/Ser genotype carriers were higher among controls than in patients, suggesting a possible protective role for these gene variants against schizophrenia. Moreover, healthy relatives had significantly higher frequencies of XRCC3 Thr+ and XPD Lys+ genotypes than unrelated healthy controls. Minor allele frequencies, haplotypes, and overtransmitted alleles of DNA repair genes were also identified. CONCLUSION Our findings support XRCC1, XRCC3, hOGG1, and XPD as risk genes for schizophrenia and suggest that altered DNA repair functions may be involved in schizophrenia pathophysiology.

Apoptotic Effects of Quercitrin on DLD-1 Colon Cancer Cell Line

Quercetin, which is the most abundant bioflavonoid compound, is mainly present in the glycoside form of quercitrin. Although different studies indicated that quercitrin is a potent antioxidant, the action of this compound is not well understood. In this study, we investigated whether quercitrin has apoptotic and antiproliferative effects in DLD-1 colon cancer cell lines. Time and dose dependent antiproliferative and apoptotic effects of quercitrin were subsequently determined by WST-1 cell proliferation assay, lactate dehydrogenase (LDH) cytotoxicity assay, detection of nucleosome enrichment factor, changes in caspase-3 activity, loss of mitochondrial membrane potential (MMP) and also the localization of phosphatidylserine (PS) in the plasma membrane. There were significant increases in caspase-3 activity, loss of MMP, and increases in the apoptotic cell population in response to quercitrin in DLD-1 colon cancer cells in a time- and dose-dependent manner. These results revealed that quercitrin has antiproliferative and apoptotic effects on colon cancer cells. Quercitrin activity supported with in vivo analyses could be a biomarker candicate for early colorectal carcinoma.

Effect of TNF-α and IL-1β genetic variants on the development of myocardial infarction in Turkish population

Tumor necrosis factor-alpha (TNF-α) and interleukin 1 beta (IL-1β) genetic variants which resulting in TNF-α and IL-1 overproduction may increase susceptibility to autoimmune diseases such as atherosclerosis. We have studied the association of TNF-α G308A and IL-1β (+3953) C/T polymorphism with myocardial infarction in Turkish population. 143 patients with myocardial infarction and 213 age-matched healthy controls were included in the study. In univariant analysis, the frequencies of IL-1β, TNF-α genotype or allele, and haplotype of C:A and T:A were significantly elevated in patients when compared with those of controls. GA genotype of TNF-α, T allele of IL-1β and A of TNF-α allele seem to be risk factors for myocardial infarction. In contrast, CC genotype of IL-1β and GG genotype of TNF-α have protective effect against myocardial infarction. In multivariate logistic regression analysis, TNF-α A allele, gender and smoking were associated with myocardial infarction. In conclusion, we can state that TNF-α A allele might be associated with myocardial infarction.

Genetic variants of SDF-1 and CXCR4 genes in endometrial carcinoma

In this study, we aimed to investigate a possible association between the Stromal cell-derived factor-1 (SDF-1) and CXCR4 polymorphisms and the risk of developing endometrial carcinoma. SDF-1 3′A and CXCR4 gene polymorphisms was performed by polymerase chain reaction (PCR) and restriction fragment length polymorphism in 139 healthy individuals and 113 patients with endometrial carcinoma. In our study groups SDF-1 3′A AA genotype frequency was higher in patients that of controls and individuals who had AA genotype showed a 2.6-fold increased risk for endometrial cancer. The carriers of CXCR4 T allele were higher in patients compared with controls and individuals who had TT genotype had a 2.5-fold high risk for endometrial carcinoma. Our finding suggest that there was no significant association between the (SDF-1) and CXCR4 polymorphisms and endometrium cancer risk. Further studies in a larger population are needed to better elucidate the role of (SDF-1) and CXCR4 gene polymorphisms in the risk of endometrial carcinogenesis. To the best of our knowledge, this is the first study to show such an association.

The role of components of the extracellular matrix and inflammation on oral squamous cell carcinoma metastasis

OBJECTIVES Oral squamous cell carcinoma (OSCC) accounts for about 90% of malignant oral lesions, and is identified as the most frequently occurring malignant tumour of oral structures. We aimed to investigate the genes and pathways related with metastasis on Turkish OSCC patients. MATERIALS AND METHODS We performed whole genome expression profiling array on an Illumina platform. A total of 24 samples with 12 OSCC and 12-paired controls that had no tumour were included in the study. Hierarchic clustering and heat map were used for data visualisation and p-values assessed to identify differentially expressed genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Ingenuity Pathway Systems (IPA) analysis were performed to consider biologic meaning of differential expression of the genes between tumour and control groups. RESULTS We identified 790 probe sets, corresponding to 648 genes that were effective in separating invasive and metastatic OSCC. Consequently, we found statistically relevant expression results on extracellular matrix members on MMPs such as MMP3, MMP10, MMP1 and MMP9; on laminin such as LAMC2, LAMA3 and LAMB3; several genes in the collagen family; and also on chemokines from the inflammation process. CONCLUSION Statistically relevant expression changes for MMPs, laminins, collagens, and chemokines, which are components of the extracellular matrix and inflammation process, may be considered as a molecular biomarker for early prediction. Further studies are necessary to determine and understand the molecular mechanisms that underlie OSCC metastasis.

Therapeutic Potential of Apigenin, a Plant Flavonoid, for Imatinib-Sensitive and Resistant Chronic Myeloid Leukemia Cells

Despite the presence of many therapeutic regimens like imatinib and other tyrosine kinase inhibitors, the development of resistance, intolerance, and side effects makes chronic myeloid leukemia (CML) therapy challenging. Thus, there is a need to discover novel drugs for CML patients. In this study, we attempted to assess apigenin, a common plant dietary flavonoid, in terms of its cytotoxic, apoptotic, and cytostatic effects on imatinib-sensitive and resistant Philadelphia-positive CML cells. We analyzed apigenins effects on cell proliferation, apoptosis, caspase-3 activity, loss of mitochondrial membrane potential, and cell cycle progression in K562 and K562/IMA3 cells. Furthermore, we described genes and gene networks that are modulated in CML in response to apigenin. Results of our study revealed that apigenin has cytotoxic and apoptotic effects on both cell types. We also displayed that apigenin induced G2/M arrest in K562 cells while arresting K562/IMA3 cells in S phase especially at the highest apigenin concentration. The expression analysis identified a set of genes that were regulated by apigenin in K652 and K562/IMA3 cells. Association of modulated genes with biological functional groups identified several networks affected by apigenin including cell survival, proliferation, cell death, cell cycle, and cell signalling pathways.