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Ustundag, Fumet Duygu/0000-0001-5290-8924 WOS: 000550941000001 PubMed ID: 32693643 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin that damages dopaminergic neurons. Zebrafish has been shown to be a suitable model organism to investigate the molecular pathways in the pathogenesis of Parkinson's disease and also for potential therapeutic agent research. Boron has been shown to play an important role in the neural activity of the brain. Boronic acids are used in combinatorial approaches in drug design and discovery. The effect of 3-pyridinylboronic acid which is an important sub-class of heterocyclic boronic acids has not been evaluated in case of MPTP exposure in zebrafish embryos. Accordingly, this study was designed to investigate the effects of 3-pyridinylboronic acid on MPTP exposed zebrafish embryos focusing on the molecular pathways related to neurodegeneration and apoptosis by RT-PCR. Zebrafish embryos were exposed to MPTP (800 mu M); MPTP + Low Dose 3-Pyridinylboronic acid (50 mu M) (MPTP + LB) and MPTP + High Dose 3-Pyridinylboronic acid (100 mu M) (MPTP + HB) in well plates for 72 hours post fertilization. Results of our study showed that MPTP induced a P53 dependent and Bax mediated apoptosis in zebrafish embryos and 3-pyridinylboronic acid restored the locomotor activity and gene expressions related to mitochondrial dysfunction and oxidative stress due to the deleterious effects of MPTP, in a dose-dependent manner.

Regulation of telomerase activity is thought to participate in the cellular response to ionizing radiation. Epigenetic mechanisms play a role in this regulation, as well as other mechanisms such as transcription, phosphorylation, etc. Here, we investigated chromatin modifications in telomerase promoter upon exposure to ionizing radiation in human mesenchymal stem cells (hMSC) and telomerase-immortalized hMSCs (hMSC-telo1) together with a hMSC-telo1 cell line in which TRF2 expression was partially repressed (siTRF2 hMSC-telo1). Histone methylations and acetylations were compared in all cell lines after exposure to various doses of ionizing radiation (0.1, 1, 2.5 and 15 Gy) using chromatin immunoprecipitation assay. hTERT gene was shown to be quickly regulated through H3, H4 acetylations, as well as with H3K4 and H3K9 methylations, following radiation exposure, although the kinetic of hMSC-telo1 cells were different, indicative of the higher radioresistivity of these cells. To the author's surprise, there was an upregulation of endogenous telomerase activity in the hMSC-telo1 cells, even though the cells had already expressed high levels of ectopic hTERT. Our results show that telomerase regulation is one of the primary actions in response to damage and epigenetic factors play a major role in this regulation. Our results also suggested that partial silencing of TRF2 enhances the radiosensitivity of these cells, and endogenous telomerase is upregulated upon radiation, even under ectopic expression of hTERT in these cells.

The dopamine transporter (DAT) plays a role in the termination of dopaminergic neurotransmission; thereby it is accepted as the primary target of various psychostimulants. N-terminal phosphorylation of DAT has been proposed as a regulator in different DAT functions, such as amphetamine-induced efflux or PKC/PKA-mediated responses. To understand the role of N-terminal conformational changes in dopamine transporter structure and function, the fluorescence resonance energy transfer (FRET) method was applied to various DAT constructs fluorescently labeled at the N-terminus and substrate-induced conformational changes were determined using rhodamine-labeled cocaine analog JHC1-64 in three DAT mutants. The results indicated that the construct with YFP inserted into the N-terminal position-55 displayed effective interaction with the substrate and simultaneous mutation of two serine residues (S7 and S12) to alanine or aspartic acid demonstrated similar phenotypes as their wild-type (WT) counterparts. FRET was detectable for N-terminal p55 YFP WT, Ser/Ala, and Ser/Asp forms, but there was no significant difference among the three mutants, contrary to our expectations based on the previously proposed roles of these serine residues. In addition, three mutants (K264A, D345A, and Y335A) implemented in the position-55 YFP background were also investigated and the importance of Y335 in the translocation cycle and in the process of substrate release was verified.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used as anti-inflammatory and analgesic agents. This family of drugs suppresses prostaglandin synthesis through inhibition of cyclooxygenase (COX) enzymes. Recent studies showed that anti-carcinogenic effects of these drugs are especially mediated by COX-2 enzyme. Etodolac is a COX-2 inhibitor and though not perfectly selective, it exhibits “preferential selectivity„ for COX-2. In this study, the anti-proliferative and apoptotic effects of etodolac and its hydrazone or triazole derivatives (SGK 206 and SGK 242, respectively), were investigated on prostate cancer cell line PC-3 and human colorectal carcinoma cell line HT-29. Our data showed that SGK 206 and SGK 242 were more effective in the inhibition of proliferation and induction of apoptosis compared to etodolac in both cell lines.

The anticancer activity of Zingiber officinalis (ginger) is an area of active research. However, data is quite limited regarding its action and mechanism, especially in hematologic cancer types. Here, antiproliferative and apoptotic effects of whole extract of the rhizome of Zingiber officinalis (ZOWE), was investigated in K562 cell line derived from a chronic myeloid leukemia (CML) patient. Various concentrations of whole extract (0, 10, 25, 50 and 100 μM) were tested in K562 cultures. Cytotoxicity and apoptosis was assessed with appropriate methods, as well as cellular ROS levels. In this study, we showed that ZOWE inhibited proliferation of K562 cells substantially, when compared to peripheral blood mononuclear cells (PBMCs) isolated from healthy donor. Increased Bax/Bcl-2 ratio, reduced mitochondrial membrane potential and increased PARP cleavage demonstrated that ZOWE inhibited proliferation by induction of apoptosis. These changes were coupled with an increase of reactive oxygen species (ROS) production. Furthermore, ZOWE addition to the culture also reduced expression levels of survival proteins pAkt and survivin, in a concentration dependent manner. Our results clearly mark that ZOWE causes to a reduction in cell viability, an induction of apoptosis and elevation in ROS levels in chronic myeloid leukemia cells and effects are significantly different from healthy peripheral blood mononuclear cells, further supporting its potential therapeutic value.

BACKGROUND: Telomeres are protective caps consisted of specific tandem repeats (5′-TTAGGG-3′). Shortening of telomeres at each cell division is known as "mitotic clock" of the cells, which renders telomeres as important regulators of lifespan. TRF2 is one of the critical members of shelterin complex, which is a protein complex responsible from the preservation of cap structure, and loss or mutation of TRF2 results in DNA damage, senescence or apoptosis. Since cancer is frequently associated with aberrant cell cycle progression, defective DNA repair or apoptosis pathways, TRF2 could be one likely candidate for cancer therapy. Here we investigated the prognostic role of TRF2 levels in cervical cancer patients. Fold-induction rates were evaluated with respect to median values after real-time PCR analysis. Overall survival, distant disease-free and local recurrence-free survival rates were calculated using Kaplan-Meier long rank test. RESULTS: Both five year overall- and disease-free survival rates were longer in patients with higher TRF2 expression compared to lower expression, but results were not statistically significant (69.2% vs 28.9%, respectively). Mean local recurrence-free survivals (LRF) were very close ( 58.6, CI: 44.3-72.9 vs 54.5, CI: 32.1-76.9 months) for high and low expressions, respectively. Cumulative proportion of LRF at the end of five year period was 76.9% for high and 57.1% for low TRF2 expression (P = 0.75). Statistically significant difference was found between survival ratios and Bcl-xL and p53 gene expressions, but not with TRF2. A respectable correlation between TRF2 expression and apoptosis along with distant metastasis was noted (P = 0.045 and 0.036, respectively). Additionally, high TRF2 expression levels had a positive impact in five year survival rate of stage IIIB-IVA patients (P = 0.04). CONCLUSIONS: Our results support the role of TRF2 in apoptosis and imply a positive relation with distant metastases and survival in advanced stage patients. The remarkable difference in survival periods of patients with different TRF2 expressions suggest that TRF2 may be a candidate factor to estimate survival for cervical cancer, a preliminary observation which should further be verified with a larger cohort.

Dopamine has been shown to influence blood pressure by regulating renal sodium excretion through direct interaction with the dopamine receptors, especially with the Dopamine D1 receptor (DRD1). To better understand the role of polymorphisms in those effects, we investigated the association between two polymorphic sites in the DRD1 promoter region (A-48G, G-94A) and essential hypertension in the Turkish population. The DRD1 variants were genotyped by restriction fragment length polymorphism (RFLP) analysis. A total of 205 unrelated individuals were enrolled in the study. We found that genotype distributions and allele frequencies of the control and hypertensive subjects were very similar and did not show any significant difference with respect to blood pressure (BP) and hypertension. Contribution of the gene variances in BP or hypertension by sex differences and dependence on body mass index (BMI) were also evaluated. Distribution of genotypes and allele frequencies were found to be in line with previous reports. However, increments detected in hypertensive subjects were far from being statistically significant.

Amac: Dopamin tasiyicilar (DAT) dopaminin sinaptik gerialimindan ve boylelikle sinirsel iletinin cabuk sonlanmasindan sorumludur. Bu proteinler aliskanlik yapici kokain, amfetamin gibi maddelerin de etki merkezlerini olusturur. Proteinin N-ucunda bulunan Serin 7 ve 12’nin fosforilasyon bakimindan kritik amino asitler oldugu bilinmektedir. Bu calismada N-ucu ile kokain baglama bolgesi arasindaki uzaklik, yaban tip ve Ser7/12Asp ve Ser7/12Ala mutantlarinda belirlenmistir. Gerec ve Yontem: Sari-floresan protein (YFP) ve mutasyonlar DAT’in N-terminal ucuna 2-asamali PCR ile yerlestirilmistir. Dopamin geri-alim testleri yapilmis ve konfokal mikroskopta verici-agartma yontemi ile Forster rezonans enerji transferi (FRET) mesafeleri belirlenmistir. Bulgular: Tum N-ucundan YFP-etiketlenmis DAT proteinleri duzgun olarak hucre yuzeyine tasinmistir. Km degerleri sirasiyla yaban tip, Ser7/12Ala and Ser7/12/Asp mutantlari icin 0.76, 0.75 ve 1.24 mM olarak saptanmistir. FRET etkinligi yaban-tip DAT icin 0.15 olarak bulunmus ve FRET uzakligi 68.4 A olarak bulunmustur. Diger konstraktlarda FRET etkinlikleri negatiftir ve enerji transferi saptanmamistir. Sonuc: Veriler bize N-ucu bolgesinin kokain baglama bolgesi ile FRET mesafesinde oldugunu ve kritik serin rezidulerinin mutasyonlarinin (Ser7/12Asp) bu mesafeyi arttirdigini gostermektedir