IZTECH Research Centers Collection / İYTE Araştırma Merkezleri Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/11147/2636
Browse
Search Results
Article Citation - WoS: 8Citation - Scopus: 8Nkx3.1 Contributes To S Phase Entry and Regulates Dna Damage Response (ddr) in Prostate Cancer Cell Lines(Academic Press Inc., 2011) Erbaykent Tepedelen, Burcu; Özmen, Besra; Varışlı, Lokman; Gönen Korkmaz, Ceren; Debeleç Bütüner, Bilge; Hamid, Syed Muhammad; Çakmak, Özgür Yılmazer; Korkmaz, Kemal SamiNKX3.1 is an androgen-regulated homeobox gene that encodes a tissue-restricted transcription factor, which plays an important role in the differentiation of the prostate epithelium. Thus, the role of NKX3.1 as a functional topoisomerase I activity enhancer in cell cycle regulation and the DNA damage response (DDR) was explored in prostate cancer cell lines. As an early response to DNA damage following CPT-11 treatment, we found that there was an increase in the γH2AX (S139) foci number and that total phosphorylation levels were reduced in PC-3 cells following ectopic NKX3.1 expression as well as in LNCaP cells following androgen administration. Furthermore, upon drug treatment, the increase in ATM (S1981) phosphorylation was reduced in the presence of NKX3.1 expression, whereas DNA-PKcs expression was increased. Additionally, phosphorylation of CHK2 (T68) and NBS1 (S343) was abrogated by ectopic NKX3.1 expression, compared with the increasing levels in control PC-3 cells in a time-course experiment. Finally, NKX3.1 expression maintained a high cyclin D1 expression level regardless of drug treatment, while total γH2AX (S139) phosphorylation remained depleted in PC-3, as well as in LNCaP, cells. Thus, we suggest that androgen regulated NKX3.1 maintains an active DDR at the intra S progression and contributes to the chemotherapeutic resistance of prostate cancer cells to DNA damaging compounds.Article Citation - WoS: 39Citation - Scopus: 49Prevalence and Antibiotic Resistance of Foodborne Staphylococcus Aureus Isolates in Turkey(Mary Ann Liebert Inc., 2011) Aydın, Ali; Muratoğlu, Karlo; Sudağıdan, Mert; Bostan, Kamil; Okuklu, Burcu; Harsa, ŞebnemIn this study, 154 Staphylococcus aureus isolates were detected from 1070 food samples (14.4%) collected from seven cities in Turkey. Antimicrobial susceptibility testing against 21 antibiotics was performed by agar disk diffusion method, and those isolates resistant to any antibiotic were further analyzed to determine minimum inhibitory concentration by E-test and polymerase chain reaction analysis of vanA and mecA genes. According to disk diffusion test results, a total of 139 strains were resistant to at least one tested antibiotic, with 39 (25.3%) strains being multidrug resistant (MDR) and the other 15 strains being susceptible to all antibiotics. Penicillin G, linezolid, erythromycin, and tetracycline took up 71.4%, 23.4%, 18.2%, and 15.6% of the tested strains, respectively. In addition, all of the strains were susceptible to vancomycin, oxacillin, cefoxitin, and imipenem. Only one strain (S158B) was resistant to both teicoplanin and cefazolin. On the other hand, the presence of vanA and mecA genes was not detected in the strains. Pulsed-field gel electrophoresis analysis was used to identify genetic-relatedness of the MDR strains. It is noteworthy that some strains from different sources showed 100% homology; however, some of MDR strains were found unrelated with 60% or less homology. The high diversity observed in pulsed-field gel electrophoresis results indicated the possible contamination of S. aureus from different sources and routes.
