Moleküler Biyoloji ve Genetik Bölümü / Department of Molecular Biology and Genetics
Permanent URI for this collectionhttps://hdl.handle.net/11413/6788
Browse
Browsing Moleküler Biyoloji ve Genetik Bölümü / Department of Molecular Biology and Genetics by Author "Akçay, İzzet Mehmet"
Now showing 1 - 2 of 2
- Results Per Page
- Sort Options
Publication Bag-1 Silencing Enhanced Chemotherapeutic Drug-induced Apoptosis in MCF-7 Breast Cancer Cells Affecting PI3K/Akt/mTOR and MAPK Signaling Pathways(2019-01-19) Akçay, İzzet Mehmet; Dinler Doğanay, Gizem; ARISAN, ELİF DAMLA; KILBAŞ, PELİN ÖZFİLİZ; 195744; 152975; 113920The multifunctional anti-apoptotic Bag-1 protein has important roles in apoptosis, proteasome-mediated degradation, transcriptional regulation, and intracellular signaling. Bag-1 promotes cell survival and proliferation, and is overexpressed in breast cancer. Therefore, Bag-1-targeted therapy might be a promising strategy to treat breast cancer. However, the effects of Bag-1 silencing in combination with conventional chemotherapeutic drugs on cell viability and major signaling pathways have not yet been fully investigated in breast cancer cells. In this study, we investigated the cytotoxic effects of Bag-1 silencing, alone and in combination with cisplatin or paclitaxel treatment, in MCF-7 breast cancer cells. Bag-1 knockdown by shRNA or siRNA transfection sensitized MCF-7 cells to apoptosis induced by cisplatin or paclitaxel. Combination of Bag-1 silencing and drug treatment more potently downregulated the pro-survival PI3K/Akt/mTOR and p44/42 mitogen activated protein kinase (MAPK) pathways, and more potently upregulated the stress-activated p38 and SAPK/JNK MAPK pathways. Bag1-silenced drug-treated cells had also highly reduced proliferative capacity, downregulated cyclin–cyclin dependent kinase complexes and upregulated tumor suppressors p21 and Rb. These results overall indicated that Bag-1 silencing enhanced cisplatin- or paclitaxel-induced cytotoxicity through multiple pathways. In conclusion, Bag-1 targeted therapy might enhance the therapeutic potential of conventional anti-cancer drugs in the treatment of breast cancer.Publication Interactome Analysis of Bag-1 Isoforms Reveals Novel Interaction Partners in Endoplasmic Reticulum-Associated Degradation(Public Library Science, 2021) Can, Nisan Denizce; Baştürk, Ezgi; Kızılboğa, Tuğba; Akçay, İzzet Mehmet; Dingiloğlu, Baran; Tatlı, Özge; Acar, Sevilay; KILBAŞ, PELİN ÖZFİLİZ; Elbeyli, Efe; Muratcioglu, Serena; Jannuzzi, Ayşe Tarbin; Gürsoy, Attila; Doğanay, Hamdi Levent; Yılmaz, Betül Karademir; Doğanay, Gizem DinlerBag-1 is a multifunctional protein that regulates Hsp70 chaperone activity, apoptosis, and proliferation. The three major Bag-1 isoforms have different subcellular localizations and partly non-overlapping functions. To identify the detailed interaction network of each isoform, we utilized mass spectrometry-based proteomics and found that interactomes of Bag-1 isoforms contained many common proteins, with variations in their abundances. Bag-1 interactomes were enriched with proteins involved in protein processing and degradation pathways. Novel interaction partners included VCP/p97; a transitional ER ATPase, Rad23B; a shuttling factor for ubiquitinated proteins, proteasome components, and ER-resident proteins, suggesting a role for Bag-1 also in ER-associated protein degradation (ERAD). Bag-1 pull-down from cells and tissues from breast cancer patients validated these interactions and showed cancer-related prominence. Using in silico predictions we detected hotspot residues of Bag-1. Mutations of these residues caused loss of binding to protein quality control elements and impaired proteasomal activity in MCF-7 cells. Following CD147 glycosylation pattern, we showed that Bag-1 downregulated VCP/p97-dependent ERAD. Overall, our data extends the interaction map of Bag-1, and broadens its role in protein homeostasis. Targeting the interaction surfaces revealed in this study might be an effective strategy in the treatment of cancer.