Person: YALÇIN, ABDULLAH
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YALÇIN
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ABDULLAH
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Publication Regulation of twist and slug by PFKFB2(Elsevier, 2015-09-01) Yalçın, A.; Özcan, S. C.; Güzel, S.; Chesney, J.; YALÇIN, ABDULLAH; Özcan, S. Can; GÜZEL, SAİME; Veteriner Fakültesi; Biyokimya Ana Bilim Dalı; 0000-0001-8519-8375; 0000-0003-0796-5000; HKM-4820-2023; ABI-4164-2020; AAA-6938-2022; AAH-4275-2021Publication 6-Phosphofructo-2-kinase (PFKFB3) promotes cell cycle progression and suppresses apoptosis via Cdk1-mediated phosphorylation of p27(Nature Publishing Group, 2014-07-01) Yalçın, Abdullah; Clem, B. F.; Imbert-Fernandez, Y.; Özcan, Selahattin Can; Peker, Sabire; O'Neal, J.; Klarer, A. C.; Clem, A. L.; Telang, S.; Chesney, J.; YALÇIN, ABDULLAH; Özcan, Selahattin Can; Peker, Sabire; Veteriner Fakültesi; Histoloji ve Embriyoloji Ana Bilim Dalı; 0000-0001-8519-8375; HKM-4820-2023; ABI-4164-2020; AAA-6938-2022; FUW-0951-2022The control of glucose metabolism and the cell cycle must be coordinated in order to guarantee sufficient ATP and anabolic substrates at distinct phases of the cell cycle. The family of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases (PFKFB1-4) are well established regulators of glucose metabolism via their synthesis of fructose-2,6-bisphosphate (F2,6BP), a potent allosteric activator of 6-phosphofructo-1-kinase (Pfk-1). PFKFB3 is overexpressed in human cancers, regulated by HIF-1 alpha, Akt and PTEN, and required for the survival and growth of multiple cancer types. Although most functional studies of the role of PFKFB3 in cancer progression have invoked its well-recognized function in the regulation of glycolysis, recent observations have established that PFKFB3 also traffics to the nucleus and that its product, F2,6BP, activates cyclin-dependent kinases (Cdks). In particular, F2,6BP stimulates the Cdk-mediated phosphorylation of the Cip/Kip protein p27 (threonine 187), which in turn results in p27's ubiquitination and proteasomal degradation. As p27 is a potent suppressor of the G1/S transition and activator of apoptosis, we hypothesized that the known requirement of PFKFB3 for cell cycle progression and prevention of apoptosis may be partly due to the ability of F2,6BP to activate Cdks. In this study, we demonstrate that siRNA silencing of endogenous PFKFB3 inhibits Cdk1 activity, which in turn stabilizes p27 protein levels causing cell cycle arrest at G1/S and increased apoptosis in HeLa cells. Importantly, we demonstrate that the increase in apoptosis and suppression of the G1/S transition caused by siRNA silencing of PFKFB3 expression is reversed by co-siRNA silencing of p27. Taken together with prior publications, these observations support a model whereby PFKFB3 and F2,6BP function not only as regulators of Pfk-1 but also of Cdk1 activity, and therefore serve to couple glucose metabolism with cell proliferation and survival in transformed cells.Publication Expression of dual-specifiicity phosphatases in tgfss1-induced emt in skov3 cells(Tubitak Scientific & Technological Research Council Turkey, 2023-01-01) Güler, Sabire; GÜLER, SABİRE; Yalçın, Abdullah; YALÇIN, ABDULLAH; Veteriner Fakültesi; Histoloji ve Embriyoloji Ana Bilim DalıBackground/aim: The study aims to profile the dual-specificity phosphatases (DUSP) expression in response to Transforming growth factor (31 (TGF(31)-induced epithelial-mesenchymal transition (EMT) in ovarian adenocarcinoma cells.Materials and methods: The ovarian adenocarcinoma cell line SKOV3 was used as a TGF(31-induced EMT model. Cells were incubated with 5 ng/mL TGF(31 to induce EMT. EMT was confirmed with real-time qPCR, western blot, and immunofluorescence analyses of various EMT markers. Western blot was used to analyze phospho-and total MAPK protein levels. Typical and atypical DUSPs mRNA expression profile was determined by real-time qPCR.Results: The epithelial marker E-cadherin expressions were decreased and mesenchymal EMT markers Snail and Slug expression levels were increased after TGF(31 induction. Phosphorylation of ERK1/2 and p38 MAPK were enhanced in response to TGF(31 treatment. The expression of DUSP2, DUSP6, DUSP8, DUSP10, and DUSP13 were decreased while DUSP7, DUSP16, DUSP18, DUSP21, and DUSP27 were increased by TGF(31.Conclusion: TGF(31 induced EMT which was accompanied by increased activity of MAPKs, and led to marked changes in expressions of several DUSPs in SKOV3 cells.Publication 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase-3 regulates the epithelial-mesenchymal transition in tumor cells(Wiley-blackwell, 2016-09-01) McNally, L.; Yalcin, Abdullah; YALÇIN, ABDULLAH; Sevinc, E.; Guzel, S.; GÜZEL, SAİME; Özcan, C.; Şamlı, H.; ŞAMLI, HALE; 0000-0001-8519-8375; 0000-0003-0796-5000; 0000-0002-6453-025X; 0000-0002-8012-6097; AAH-4275-2021; AAA-6938-2022; AAH-6488-2021; ABI-4164-2020Publication PFKFB2 regulates glycolysis and proliferation in pancreatic cancer cells(Springer, 2020-05-15) Özcan, Selahattin C.; Sarıoğlu, Aybike; Altunok, Tuğba H.; Akkoç, Ahmet; Güzel, Saime; Güler, Sabire; Imbert-Fernandez, Yoannis; Muchut, Robertino J.; Iglesias, Alberto A.; Gürpınar, Yunus; Clem, Amy L.; Chesney, Jason A.; Yalçın, Abdullah; Sarıoğlu, Aybike; Altunok, Tuğba H.; AKKOÇ, AHMET; GÜZEL, SAİME; GÜLER, SABİRE; Gürpınar, Yunus; YALÇIN, ABDULLAH; Veteriner Fakültesi; Biyokimya Ana Bilim Dalı; 0000-0002-8287-6617; 0000-0003-1263-3799; 0000-0003-0796-5000; 0000-0002-7698-0872; 0000-0001-8519-8375; S-2474-2018; GCY-0775-2022; DTZ-3578-2022; AAH-4275-2021; HNI-3945-2023; ABI-4164-2020Tumor cells increase glucose metabolism through glycolysis and pentose phosphate pathways to meet the bioenergetic and biosynthetic demands of rapid cell proliferation. The family of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases (PFKFB1-4) are key regulators of glucose metabolism via their synthesis of fructose-2,6-bisphosphate (F2,6BP), a potent activator of glycolysis. Previous studies have reported the co-expression of PFKFB isozymes, as well as the mRNA splice variants of particular PFKFB isozymes, suggesting non-redundant functions. Majority of the evidence demonstrating a requirement for PFKFB activity in increased glycolysis and oncogenic properties in tumor cells comes from studies on PFKFB3 and PFKFB4 isozymes. In this study, we show that the PFKFB2 isozyme is expressed in tumor cell lines of various origin, overexpressed and localizes to the nucleus in pancreatic adenocarcinoma, relative to normal pancreatic tissue. We then demonstrate the differential intracellular localization of two PFKFB2 mRNA splice variants and that, when ectopically expressed, cytoplasmically localized mRNA splice variant causes a greater increase in F2,6BP which coincides with an increased glucose uptake, as compared with the mRNA splice variant localizing to the nucleus. We then show that PFKFB2 expression is required for steady-state F2,6BP levels, glycolytic activity, and proliferation of pancreatic adenocarcinoma cells. In conclusion, this study may provide a rationale for detailed investigation of PFKFB2's requirement for the glycolytic and oncogenic phenotype of pancreatic adenocarcinoma cells.Publication Transforming growth factor β1 upregulates 6‐phosphofructo‐ 2‐kinase/fructose 2,6‐bisphosphatase‐4 expression in A549 and MCF‐10A cells(Wiley, 2023-09-04) Altunok, Tuğba H.; Muchut, Robertino J.; Iglesias, Alberto A.; Yalçın, Abdullah; Altunok, Tuğba H.; YALÇIN, ABDULLAH; Veterinerlik Fakültesi; Biyokimya Ana Bilim Dalı; 0000-0003-1263-3799 ; KMY-2643-2024; JTP-1429-2023Transforming growth factor beta 1 (TGF beta 1) induces a cellular process known as epithelial-mesenchymal transition (EMT) associated with metabolic reprogramming, including enhanced glycolysis. Given the involvement of 6-phosphofructo-2-kinase/ fructose 2,6-bisphosphatase (PFKFB) enzymes in glycolysis, we aimed to investigate whether TGF beta 1 regulates expressions of PFKFB genes and if PFKFBs are required for TGF beta 1-driven phenotypes. A549 and MCF-10A cell lines were used as TGF beta 1driven EMT models. Messenger RNA expressions of PFKFB and EMT genes were determined by real-time quantitative polymerase chain reaction. A small interfering RNA approach was used to deplete PFKFB4 expression. A Matrigel invasion assay was conducted to assess the effect of PFKFB4 silencing on the TGF ss 1-enhanced invasion of A549 cells. F2,6BP levels were analyzed using an enzyme-coupled assay. Glucose and lactate concentrations were determined using colorimetric assays. TGF beta 1 robustly induced expression of the fourth isoform of PFKFBs, PFKFB4, in both cell lines. PFKFB4 depletion partially inhibits mesenchymal transdifferentiation caused by TGF beta 1 in A549 cells, as assessed by microscopy. Inductions of Snail in MCF-10A cells and Fibronectin in A549 cells and repressions of E-cadherin in both cell lines by TGF beta 1 are attenuated by PFKFB4 silencing. PFKFB4 silencing reduces F2,6BP and glycolytic activity, although TGF beta 1 alone does not affect these parameters. Finally, PFKFB4 depletion suppresses the TGF beta 1-driven invasion of A549 cells through Matrigel. Presented data suggest that TGF ss 1 induces the expression of PFKFB4 in A549 and MCF-10 cells, and PFKFB4 may be required for TGF beta 1-driven phenotypes such as EMT and invasion in these models.Publication Upregulation of dual-specificity phosphatase-26 is required for transforming growth factor β1(TGFβ1)-induced Epithelial-mesenchymal transition in A549 and PANC1 cells(Springer, 2022-09-02) Güler, Sabire; Zık, Berrin; Yalçın, Abdullah; GÜLER, SABİRE; ZIK, BERRİN; YALÇIN, ABDULLAH; Veteriner Fakültesi; Biyokimya Ana Bilim Dalı; 0000-0002-7367-6859; 0000-0001-8519-8375; AAH-9810-2021; ABI-4164-2020; AAH-8807-2021; A-5261-2016Background Transforming Growth Factor beta (TGF beta) proteins are potent inducers of the epithelial-mesenchymal transition (EMT) in tumor cells. Although mitogen-activated protein kinase (MAPK) family has been shown to be involved in TGF beta-induced EMT, role of Dual Specificity Phosphatases (DUSP), key regulators of MAPK activity, in TGF beta-induced EMT is largely unkonwn.Methods and results Real-time qPCR analyses were performed to determine the effect of TGF beta 1 on expression of EMT genes and DUSP proteins in the non-small cell lung cancer model A549 and pancreatic adenocarcinoma model PANC1 cells. Western blot analyses were conducted to study the changes in protein levels of EMT proteins and select DUSP proteins, as well as phosphorylations of MAPK proteins upon TGF beta 1 stimulation. Small interfering RNA (siRNA) was utilized to reduce expressions of DUSP genes. We observed that the EMT phenotype coincided with increases in phosphorylations of the MAPK proteins ERK1/2, p38MAPK, and JNK upon TGF beta 1 stimulation. Real-time qPCR analysis showed increases in DUSP15 and DUSP26 mRNA levels and Western blot analysis confirmed the increase in DUSP26 protein levels in both A549 and PANC1 cells treated with TGF beta 1 relative to control. Silencing of DUSP26 expression by siRNA markedly suppressed the effect of TGF beta 1 on E-cadherin and mesenchymal genes in the cells.Conclusions Data provided suggest that TGF beta 1 modulates the expression of DUSP genes and that upregulation of DUSP26 may be required for TGF beta 1-promoted EMT in A549 and PANC1 cells. Further studies should be carried out to elucidate the requirement of individual DUSPs in TGF beta 1-associated EMT in tumor cells.Publication Overexpression of dual-specificity phosphatases 4 and 13 attenuates transforming growth factor β1-induced migration and drug resistance in A549 cells in vitro(Academic Press Inc Elsevier Science, 2022-03-23) Güler, Sabire; Altunok, Tuğba H.; Sarıoğlu, Aybike; Zik, Berrin; Aşmaz, Deniz; Kayapunar, Nuray; Sönmez, Öner; Tepedelen, Burcu Erbaykent; Yalçın, Abdullah; GÜLER, SABİRE; Altunok, Tuğba H.; Sarıoğlu, Aybike; ZIK, BERRİN; Aşmaz, Deniz; Kayapunar, Nuray; SÖNMEZ, ÖNER; Tepedelen, Burcu Erbaykent; YALÇIN, ABDULLAH; Veteriner Fakültesi; Biyokimya Ana Bilim Dalı; 0000-0002-7367-6859; 0000-0003-1263-3799; 0000-0002-1062-332X; 0000-0001-8519-8375; 0000-0002-8287-6617; 0000-0001-6468-8535; AAH-8807-2021; KMY-2643-2024; S-2474-2018; AAH-9810-2021; HPG-0648-2023; GXM-5514-2022; DTN-7054-2022; AAH-6436-2021; ABI-4164-2020Transforming growth factor-beta (TGF beta) proteins induce an epithelial-mesenchymal transition (EMT) programme that is associated with increased invasive and drug-resistant phenotype of carcinoma cells. In addition to the canonical pathway involving SMAD proteins, the mitogen-activated kinase (MAPK) pathway via extracellular signal-regulated kinases 1/2 (ERK1/2) is also involved in promoting and maintaining a mesenchymal phenotype by tumor cells following TGF beta signal activation. As dual-specificity phosphatases (DUSPs) regulate ERK1/2 activity by dephosphorylation, we aimed to examine DUSPs' expression upon TGF beta stimulation and whether DUSPs play a role in the EMT and related phenotypes promoted by TGF beta 1 in A549 cells. We found that TGF beta 1 stimulation led to marked changes in several DUSP proteins, including significant decreases in DUSP4 and DUSP13 expressions. We then showed that the ectopic co-expression of DUSP4/13 suppresses TGF beta 1-induced ERK1/2 phosphorylation and protein levels of the EMT transcription factors Snail and Slug proteins. We then demonstrated that DUSP4/13 co-expression partially inhibited TGF beta 1-promoted migration, invasion, and chemoresistance in A549 cells. Collectively, this report provides data for the involvement of DUSP4/13 in malignant phenotypes regulated by TGF beta 1 in A549 cells. (C) 2022 Elsevier Inc. All rights reserved.Publication Increased expression of 6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase-3 is required for growth of mouse embryonic stem cells that are undergoing differentiation(Springer, 2022-11-10) Güzel, Saime; Gürpınar, Yunus; Altunok, Tuğba Hazal; Yalçın, Abdullah; GÜZEL, SAİME; Altunok, Tuğba Hazal; YALÇIN, ABDULLAH; Veteriner Fakültesi; Biyokimya Ana Bilim Dalı; 0000-0001-8519-8375 ; HEF-9447-2022; GCY-0775-2022; ABI-4164-2020The unlimited proliferation capacity of embryonic stem cells (ESCs) coupled with their capability to differentiate into several cell types makes them an attractive candidate for studying the molecular mechanisms regulating self-renewal and transition from pluripotent state. Although the roles of 6-phosphofructo-2-kinase/fructose-2,6-bisphos-phatase family (PFKFB1-4) in cell survival, proliferation, and differentiation in tumor cells have been studied, their role in mouse ESC (mESC) biology is currently unkown. In the current study, Pfkfb isoenzyme expressions were analyzed in R1 and J1 mESCs that were cultured in the presence and absence of leukemia inhibitory factor (LIF). We report that expression of the Pfkfb3 isoenzyme was markedly increased when mESCs were promoted to differentiate upon LIF removal. We then demonstrated that Pfkfb3 silencing induced the differentiation marker Brachyury suggesting that Pfkfb3 may be required for the regulation of mesodermal differentiation of mESCs. Furthermore, we show that the increase in Pfkfb3 expression is required for the growth of early differentiated mESCs. Although these results provide important insights into the early differentiation of mESCs with regard to Pfkfb expressions, further mechanistic studies will be needed for understanding the pathways and mechanisms involved in regulation of proliferation and early differentiation of mESCs through Pfkfb3.Publication Simultaneous inhibition of PFKFB3 and GLS1 selectively kills KRAS transformed pancreatic cells(Academic Press, 2021-09-24) Özcan, Selahattin C.; Mutlu, Aydan; Altunok, Tuğba H.; Gürpınar, Yunus; Sarıoğlu, Aybike; Güler, Sabire; Muchut, Robertino J.; Iglesias, Alberto A.; Çelikler, Serap; Campbell, Paul M.; Yalçın, Abdullah; GÜLER, SABİRE; ÇELİKLER KASIMOĞULLARI, SERAP; YALÇIN, ABDULLAH; Mutlu, Aydan; Altunok, Tuğba H.; Sarıoğlu, Aybike; 0000-0003-1263-3799; 0000-0002-8287-6617; 0000-0002-4177-3478; 0000-0001-8519-8375; FNG-9051-2022; GCY-0775-2022; S-2474-2018; HTY-9355-2023; JCD-5015-2023; ABI-4164-2020Activating mutations of the oncogenic KRAS in pancreatic ductal adenocarcinoma (PDAC) are associated with an aberrant metabolic phenotype that may be therapeutically exploited. Increased glutamine utilization via glutaminase-1 (GLS1) is one such feature of the activated KRAS signaling that is essential to cell survival and proliferation; however, metabolic plasticity of PDAC cells allow them to adapt to GLS1 inhibition via various mechanisms including activation of glycolysis, suggesting a requirement for combinatorial anti-metabolic approaches to combat PDAC. We investigated whether targeting the glycolytic regulator 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3 (PFKFB3) in combination with GLS1 can selectively prevent the growth of KRAS-transformed cells. We show that KRAStransformation of pancreatic duct cells robustly sensitizes them to the dual targeting of GLS1 and PFKFB3. We also report that this sensitivity is preserved in the PDAC cell line PANC-1 which harbors an activating KRAS mutation. We then demonstrate that GLS1 inhibition reduced fructose-2,6-bisphosphate levels, the product of PFKFB3, whereas PFKFB3 inhibition increased glutamine consumption, and these effects were augmented by the co-inhibition of GLS1 and PFKFB3, suggesting a reciprocal regulation between PFKFB3 and GLS1. In conclusion, this study identifies a novel mutant KRAS-induced metabolic vulnerability that may be targeted via combinatorial inhibition of GLS1 and PFKFB3 to suppress PDAC cell growth. (c) 2021 Published by Elsevier Inc.