Browsing by Author "Aka, Yeliz"

Now showing 1 - 6 of 6

Cytokine expression profiles in Autism spectrum disorder: A multi-center study from Turkey
(2020) Kutuk, Meryem Ozlem; Tufan, Evren; Gokcen, Cem; Kilicaslan, Fethiye; Karadag, Mehmet; Mutluer, Tuba; Yektas, Cigdem; Coban, Nurdan; Kandemir, Hasan; Buber, Ahmet; Coskun, Seyma; Acikbas, Ufuk; Guler, Gulen; Topal, Zehra; Celik, Fatma; Altintas, Ebru; Giray, Asli; Aka, Yeliz; Kutuk, Ozgur; 0000-0002-2918-7871; 0000-0001-9854-7220; 0000-0003-2735-4805; 32563959; AAI-9626-2021; AAH-1671-2019; G-8832-2015
Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterized by impairments in communication and social interaction as well as restricted interests and repetitive behaviors. The pathogenesis of ASD is not completely understood, but a growing body of research has demonstrated that the immune response may be a contributing factor in the etiology and/or ontogeny of ASD. The aim of this study was to determine the expression levels of IL-1 beta, IL-1 alpha, IL-4, IL-6, IL-17, TNF-alpha and TGF-beta in peripheral blood mononuclear cells of children with ASD and healthy controls in order to determine the contributions of cytokines to ASD. Within the study timeframe, 195 children with ASDs (80.5% male) and 162 controls (73.6% male) were enrolled. Most children with ASD had a comorbid disorder (n = 114, 58.5%), with the most common diagnoses as Intellectual Developmental Disorder (IDD, n = 64, 32.8%) and ADHD (n = 64, 32.8%). The majority of children with ASD had severe autistic symptoms as evaluated via Childhood Autism Rating Scale (CARS, n = 130, 64.6%). The mean CARS score in the ASD sample was 40.8 (S.D. = 7.6). The patients with ASD were found to have significantly higher levels of IL-6 (p < 0.001) and significantly lower levels of IL-17 (p < 0.05, all Bonferroni corrected). Treatment tended to affect IL-4 levels. Lastly, discriminant function analysis (DFA) revealed that a combination of IL-6, IL-17 and IL-1 alpha correctly classified 56.6% of cases. Despite extensive immunological evidence suggesting immune system aberrations, further research is required to clarify the relationship between immune profiles and ASD symptoms.
Design, synthesis and in vitro apoptotic mechanism of novel pyrrolopyrimidine derivatives
(2019) Kilic-Kurt, Zuhal; Bakar-Ates, Filiz; Aka, Yeliz; Kutuk, Ozgur; 0000-0001-9854-7220; 30458413; AAH-1671-2019
In this work we described the synthesis and evaluation of cytotoxic and apoptotic activity of novel pyrrolopyrimidine derivatives against A549, PC3 and MCF-7 cells. Among the synthesized compounds, 6b, 8a, 9a and 7a, 8b displayed the significant cytotoxic activities against A549 and PC3 cells with IC50 value of 0.35, 1.48, 1.56 and 1.04, 1.89 mu M, respectively. It was found that A549 cells were more sensitive to synthesized compounds than PC3 and MCF-7 cells. In order to evaluate the mechanism of cytotoxic activity in A549, compounds 6b, 8a and 9a were selected for further studies. Annexin V binding assay and western blot analysis results revealed that 6b, 8a and 9a induced apoptosis in A549 cells by intrinsic apoptotic pathway through the activation proapoptotic proteins such as Bim, Bax, Bak, Puma and deactivation of anti-apoptotic proteins including Bcl-2, Mcl-1 and Bcl-XL accompanied by the activation of caspase-3, caspase-9 and cleavage of PARP. Also, compounds 6b, 8a and 9a triggered apoptosis in HCT116 wt cells via activation of caspase-3 and caspase-9, but not in HCT116 Bax/Bak KO cells, indicating resistance to 6b, 8a and 9a treatment.
Kinome-wide RNAi screening for mediators of ABT-199 resistance in breast cancer cells identifies Wee1 as a novel therapeutic target
(2021) Aka, Yeliz; Acikbas, Ufuk; Kutuk, Ozgur; 34171479
Antiapoptotic and proapoptotic BCL-2 protein family members regulate mitochondrial apoptotic pathway. Small molecule inhibitors of antiapoptotic BCL-2 proteins including BCL-2-specific inhibitor ABT-199 (Venetoclax) are in clinical development. However, the efficiency of ABT-199 as a single agent in solid tumors is limited. We performed a high-throughput RNAi kinome screen targeting 691 kinases to identify potentially targetable kinases to enhance ABT-199 response in breast cancer cells. Our studies identified Wee1 as the primary target kinase to overcome resistance to ABT-199. Depletion of Wee1 by siRNA-mediated knockdown or inhibition of Wee1 by the small molecule Wee1 inhibitor AZD1775 sensitized SKBR3, MDA-MB-468, T47D and CAMA-1 breast cancer cells to ABT-199 along with decreased MCL1. BH3-only proteins PUMA and BIM functionally contribute to apoptosis signaling following co-targeting BCL-2 and Wee1. Suppression of Wee1 function increased mitochondrial cell death priming. Furthermore, we found that Wee1 inhibition altered MCL1 phosphorylation and protein stability, which led to HUWE1-mediated MCL1 degradation. Our findings suggest that Wee1 inhibition can overcome resistance to ABT-199 and provide a rationale for further translational investigation of BCL-2 inhibitor/Wee1 inhibitor combination in breast cancer.
Mitochondrial estrogen receptors alter mitochondrial priming and response to endocrine therapy in breast cancer cells
(2021) Karakas, Bahriye; Aka, Yeliz; Giray, Asli; Temel, Sehime Gulsum; Acikbas, Ufuk; Basaga, Huveyda; Gul, Ozgur; Kutuk, Ozgur; 34294688
Breast cancer is the most common cancer with a high rate of mortality and morbidity among women worldwide. Estrogen receptor status is an important prognostic factor and endocrine therapy is the choice of first-line treatment in ER-positive breast cancer. However, most tumors develop resistance to endocrine therapy. Here we demonstrate that BH3 profiling technology, in particular, dynamic BH3 profiling can predict the response to endocrine therapy agents as well as the development of acquired resistance in breast cancer cells independent of estrogen receptor status. Immunofluorescence analysis and subcellular fractionation experiments revealed distinct ER-alpha and ER-beta subcellular localization patterns in breast cancer cells, including mitochondrial localization of both receptor subtypes. shRNA-mediated depletion of ER-beta in breast cancer cells led to resistance to endocrine therapy agents and selective reconstitution of ER-beta in mitochondria restored sensitivity. Notably, mitochondria-targeted ER-alpha did not restore sensitivity, even conferred further resistance to endocrine therapy agents. In addition, expressing mitochondria-targeted ER-beta in breast cancer cells resulted in decreased mitochondrial respiration alongside increased total ROS and mitochondrial superoxide production. Furthermore, our data demonstrated that mitochondrial ER-beta can be successfully targeted by the selective ER-beta agonist Erteberel. Thus, our findings provide novel findings on mitochondrial estrogen signaling in breast cancer cells and suggest the implementation of the dynamic BH3 technique as a tool to predict acquired endocrine therapy resistance.
Novel pyrrolopyrimidine derivatives induce p53-independent apoptosis via the mitochondrial pathway in colon cancer cells
(2020) Kilic-Kurt, Zuhal; Aka, Yeliz; Kutuk, Ozgur; 0000-0001-9854-7220; 32866467; AAH-1671-2019
A series of novel pyrrolopyrimidine urea derivatives were synthesized and evaluated for their anticancer activity against colon cancer cell lines. Compounds showed the remarkable cytotoxic activity on HCT-116 wt cell line. The most potent compound 4c (IC50 = 0.14 mu M) induced apoptosis in HCT-116 wt and HCT-116 p53-/- cell lines. Otherwise, treatment of HCT-116 BAX-/-BAK-/- cells with compound 4c didn't lead to activation of apoptosis, suggesting that compound 4c induces apoptotic cell death by activating BAX/BAK-dependent pathway. Moreover, while the compound 4c increase the activation of caspase-3 and caspase-9 levels in HCT116 wt and HCT-116 p53-/- cells, caspase-3 or caspase-9 activation was not observed in HCT-116 BAX-/-BAK-/- cells. In addition, compound 4c induced mitochondrial apoptosis in cells grown as oncospheroids, which better mimic the in vivo milieu of tumors. 4c treatment also activated JNK along with inhibition of prosurvival kinases such as Akt and ERK 1/2 in HCT-116 wt and HCT-116 p53 -/- cells as well as in HCT-116 BAX-/-BAK-/- cells. Notably, our results indicated that compound 4c induced mitochondrial apoptosis through activation p53-independent apoptotic signaling pathways.
RAB25 confers resistance to chemotherapy by altering mitochondrial apoptosis signaling in ovarian cancer cells
(2020) Temel, Sehime Gulsun; Giray, Asli; Karaka, Bahriye; Gul, Ozgur; Kozanoglu, Ilknur; Celik, Husnu; Basaga, Huveyda; Acikbas, Ufuk; Sucularli, Ceren; Oztop, Sidika; Aka, Yeliz; Kutuk, Ozgur; 0000-0001-5653-6080; 0000-0001-9854-7220; 0000-0002-5268-1210; 32901335; AAJ-7911-2020; AAH-1671-2019; AAE-1241-2021
Ovarian cancer remains one of the most frequent causes of cancer-related death in women. Many patients with ovarian cancer suffer from de novo or acquired resistance to chemotherapy. Here, we report that RAB25 suppresses chemotherapy-induced mitochondrial apoptosis signaling in ovarian cancer cell lines and primary ovarian cancer cells. RAB25 blocks chemotherapy-induced apoptosis upstream of mitochondrial outer membrane permeabilization by either increasing antiapoptotic BCL-2 proteins or decreasing proapoptotic BCL-2 proteins. In particular, BAX expression negatively correlates with RAB25 expression in ovarian cancer cells. BH3 profiling assays corroborated that RAB25 decreases mitochondrial cell death priming. Suppressing RAB25 by means of RNAi or RFP14 inhibitory hydrocarbon-stapled peptide sensitizes ovarian cancer cells to chemotherapy as well as RAB25-mediated proliferation, invasion and migration. Our data suggest that RAB25 is a potential therapeutic target for ovarian cancer.