Gülseren Bağcı

Parental origin and mechanisms of formation of cytogenetically recognisable de novo direct and inverted duplications

Cytogenetic, FISH, and molecular results of 20 cases with de novo tandem duplications of 18 different autosomal chromosome segments are reported. There were 12 cases with direct duplications, three cases with inverted duplications, and five in whom determination of direction was not possible. In seven cases a rearrangement between non-sister chromatids (N-SCR) was found, whereas in the remaining 13 cases sister chromatids (SCR) were involved. Paternal and maternal origin (7:7) was found almost equally in cases with SCR (3:4) and N-SCR (4:3). In the cases with proven inversion, there was maternal and paternal origin in one case each. Twenty three out of 43 cytogenetically determined breakpoints correlated with common or rare fragile sites. In five cases, including all those with proven inverse orientation, all breakpoints corresponded to common or rare fragile sites. In at least two cases, one with an interstitial duplication (dup(19)(q11q13)) and one with a terminal duplication (dup(8) (p10p23)), concomitant deletions (del(8) (p23p23.3) and del(19)(q13q13)) were found.

Utility of serum DNA and pyrosequencing for the detection of EGFR mutations in non-small cell lung cancer.

Mutations in the EGFR gene are critical determinants of treatment with EGFR tyrosine kinase inhibitors (TKIs) for non-small cell lung cancer (NSCLC) patients. DNA isolation from tumor samples usually requires surgery; therefore, we wanted to isolate DNA from circulating tumor cells by using the serum of NSCLC patients. This protocol was recently published. DNA was isolated from the serum of 52 Turkish NSCLC patients and their EGFR mutation status was examined by pyrosequencing. EGFR mutations were detected in 25 of the 52 patients (48.1%): 17 patients with delE746-A750, 2 with delE747-A750insP, and 6 with L858R. All mutations detected by pyrosequencing were confirmed by dideoxy sequencing, and the presence of the same mutations in the tumors was verified by using paraffin embedded tissues of all the patients. Mutations were detected more frequently in adenocarcinomas (24 of 36, 66.7%) than in squamous cell carcinomas (1 of 16, 6.3%) (P<0.001). These results confirm the utility of serum DNA and pyrosequencing for the detection of EGFR mutations in patients with advanced NSCLC.

Investigation of anticancer mechanism of oleuropein via cell cycle and apoptotic pathways in SH-SY5Y neuroblastoma cells

Neuroblastoma is one of the most common types of pediatric tumors that can spread quickly in neuronal tissues. Oleuropein which is active compound of olive leaves, belongs to polyphenols group and has antioxidant, anti-microbial, anti-inflammatory, anti-hypertensive and anti-carcinogenic effects. The aim of the study is to determine the therapeutic effects of oleuropein on cell proliferation, invasion, colony formation, cell cycle and apoptotic mechanisms in SH-SY5Y neuroblastoma cell line under in vitro conditions. The effect of oleuropein on cell viability was determined by XTT method. 84 cell cycle control and 84 apoptosis related genes were evaluated by RT-PCR. Effects of oleuropein on apoptosis were researched by TUNEL assay. Protein expressions were determined by western blot analysis. Effects of oleuropein on cell invasion, colony formation and migration were detected by matrigel-chamber, colony formation assay and wound-healing assay, respectively. IC50 value of oleuropein in SH-SY5Y cells was detected as 350 μM at 48th hours. It is determined that oleuropein causes cell cycle arrest by down-regulating of CylinD1,CylinD2,CyclinD3,CDK4,CDK6 and up-regulating of p53 and CDKN2A, CDKN2B, CDKN1A gene expressions. Oleuropein also induces apoptosis by inhibiting of Bcl-2 and activating of Bax,caspase-9 and caspase-3 gene expressions. Apoptotic cell ratio was found 36.4 ± 3.27% in oleuropein dose group. Oleuropein decreased invasion in SH-SY5Y cells and suppressed colony numbers in ratio of 53.6 ± 4.71%.Our results demonstrated that oleuropein can be a therapeutic agent in the treatment of neuroblastoma.

Determination of O6-Methylguanine DNA Methyltransferase Promoter Methylation in Non-Small Cell Lung Cancer

Aberrant methylation of promoter CpG islands is known to be a major inactivation mechanism of the tumor-related genes including DNA repair genes. The objective of this study was to determine the frequency of promoter methylation of the O⁶-methylguanine DNA methyltransferase (MGMT) gene as a DNA repair gene in nonsmall cell lung cancer (NSCLC) and to analyze the correlation with clinicopathological parameters including age, gender, smoking status, histological subtype, and clinical stage. Eighty patients with NSCLC were included in this study. The analysis of DNA methylation was performed on formalin-fixed, paraffin-embedded lung cancer tissues. Following DNA isolation and bisulfite treatment, DNA methylation was analyzed by methylation-specific real-time polymerase chain reaction. MGMT promoter methylation was detected in 51 of 80 (64%) NSCLC patients. There was a significant correlation between MGMT methylation and tumor stage (p = 0.01). The frequencies of the promoter methylation of MGMT gene in smokers and older patients were higher than in their counterparts. In conclusion, the present study provides strong evidence for a higher frequency of promoter methylation of the MGMT gene in NSCLC, indicating that it is a common event during the carcinogenesis of NSCLC.

Complete gonadal dysgenesis 46,XY (Swyer syndrome) in two sisters and their mother's maternal aunt with a female phenotype

OBJECTIVE To present a familial case of Swyer syndrome. DESIGN Case report. SETTING Academic medical center. PATIENT(S) Two sisters with a main complaint of primary amenorrhea and another case, their mothers maternal aunt with the same history of primary amenorrhea but married with no consanguinity and no children. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) The patients were studied from clinical, endocrinologic, and genetic perspectives. RESULT(S) Chromosome analyses revealed a 46,XY male karyotype with no detectable mosaicism in both sisters and their mothers maternal aunt. Molecular studies of sex-determining region Y and molecular investigation undertaken for the two sisters revealed SRY negativity. CONCLUSION(S) Gonadal dysgenesis can also be inherited as an X-linked disorder, and evidence exists from familial studies of perhaps autosomal inheritance.

Investigation of the effects of a sulfite molecule on human neuroblastoma cells via a novel oncogene URG4/URGCP.

AIM The aim of this study is to determine the anticancer effect of sulfite on SH-SY5Y neuroblastoma cells in vitro conditions and elucidate underlying molecular mechanism of sulfite and explore its therapeutic activity. MAIN METHODS In this study, cytotoxic effects of sulfite in SH-SY5Y cels were detected over time in a dose dependent manner with the IC50 doses ranging from 0.5 to 10 mM. Genotoxic effect of sulfite was shown by comet assay. IC50 doses in the SH-SY5Y cells were detected as 5 mM. Expression profiles of the target genes related to apoptosis and cell cycle control were determined by quantitative RT-PCR. Protein changes were determined by western blot analysis. KEY FINDINGS URG4/URGCP, CCND1, CCND2, CDK4, CDK6, E2F4 and BCL-2 gene expression levels were significantly reduced and RB1, TP53, BAX, BID, CASP2, CASP3, CASP9 and DIABLO gene expressions were significantly increased in dose group cells. The mechanism of this result may be related to sulfite dependent inhibition of cell cycle at the G1 phase by down-regulating URG4/URGCP or CCND1, CDK4, CDK6 gene expression and stimulating apoptosis via the intrinsic pathway. Sulfite suppressed invasion and colony formation in SH-SY5Y cell line using matrigel invasion chamber and colony formation assay, respectively. SIGNIFICANCE It is thought that sulfite demonstrates anticarcinogenesis activity by affecting cell cycle arrest, apoptosis s, invasion, and colony formation on SH-SY5Y cells. Sulfite may be an effective agent for treatment of neuroblastoma as a single agent or in combination with other agents.

Possible Role of GADD45γ Methylation in Diffuse Large B-Cell Lymphoma: Does It Affect the Progression and Tissue Involvement?

Objective: Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma among adults and is characterized by heterogeneous clinical, immunophenotypic, and genetic features. Different mechanisms deregulating cell cycle and apoptosis play a role in the pathogenesis of DLBCL. Growth arrest DNA damage-inducible 45 (GADD45γ) is an important gene family involved in these mechanisms. The aims of this study are to determine the frequency of GADD45γ methylation, to evaluate the correlation between GADD45γ methylation and protein expression, and to investigate the relation between methylation status and clinicopathologic parameters in DLBCL tissues and reactive lymphoid node tissues from patients with reactive lymphoid hyperplasia. Materials and Methods: Thirty-six tissue samples of DLBCL and 40 nonmalignant reactive lymphoid node tissues were analyzed in this study. Methylation-sensitive high-resolution melting analysis was used for the determination of GADD45γ methylation status. The GADD45γ protein expression was determined by immunohistochemistry. Results: GADD45γ methylation was frequent (50.0%) in DLBCL. It was also significantly higher in advanced-stage tumors compared with early-stage (p=0.041). In contrast, unmethylated GADD45γ was associated with nodal involvement as the primary anatomical site (p=0.040). Conclusion: The results of this study show that, in contrast to solid tumors, the frequency of GADD45γ methylation is higher and this epigenetic alteration of GADD45γ may be associated with progression in DLBCL. In addition, nodal involvement is more likely to be present in patients with unmethylated GADD45γ.