Qiong Wu1, Cheng Zhang1, Keren Zhang2, Qiushi Chen2, Sijin Wu3, Huang Huang1, Tianmiao Huang1, Nana Zhang1, Xue Wang1, Wenli Li1, Yubo Liu4, Jianing Zhang5. 1. School of Life Science & Pharmacy, Dalian University of Technology, Panjin, China. 2. Clinical Laboratory of BGI Health, BGI-Shenzhen, Shenzhen, China. 3. Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, USA; Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China. 4. School of Life Science & Pharmacy, Dalian University of Technology, Panjin, China. Electronic address: liuyubo@dlut.edu.cn. 5. School of Life Science & Pharmacy, Dalian University of Technology, Panjin, China. Electronic address: jnzhang@dlut.edu.cn.
Abstract
GalNAc-type O-glycosylation, initially catalyzed by polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-Ts), is one of the most abundant and complex posttranslational modifications of proteins. Emerging evidence has proven that aberrant ppGalNAc-Ts are involved in malignant tumor transformation. However, the exact molecular functions of ppGalNAc-Ts are still unclear. Here, the role of one isoform, ppGalNAc-T4, in breast cancer cell lines was investigated. The expression of ppGalNAc-T4 was found to be negatively associated with migration of breast cancer cells. Loss-of-function studies revealed that ppGalNAc-T4 attenuated the migration and invasion of breast cancer cells by inhibiting the epithelial-mesenchymal transition (EMT) process. Correspondingly, transforming growth factor beta (TGF-β) signaling, which is the upstream pathway of EMT, was impaired by ppGalNAc-T4 expression. ppGalNAc-T4 knockout decreased O-GalNAc modification of TGF-β type Ⅰ and Ⅱ receptor (TβR Ⅰ and Ⅱ) and led to the elevation of TGF-β receptor dimerization and activity. Importantly, a peptide from TβR Ⅱ was identified as a naked peptide substrate of ppGalNAc-T4 with a higher affinity than ppGalNAc-T2. Further, Ser31, corresponding to the extracellular domain of TβR Ⅱ, was identified as the O-GalNAcylation site upon in vitro glycosylation by ppGalNAc-T4. The O-GalNAc-deficient S31 A mutation enhanced TGF-β signaling activity and EMT in breast cancer cells. Together, these results identified a novel mechanism of ppGalNAc-T4-catalyzed TGF-β receptors O-GalNAcylation that suppresses breast cancer cell migration and invasion via the EMT process. Targeting ppGalNAc-T4 may be a potential therapeutic strategy for breast cancer treatment.
GalNAc-type O-glycosylation, inpan>itially catalyzed by polypeptide pan> class="Chemical">N-acetylgalactosaminyltransferases (ppGalNAc-Ts), is one of the most abundant and complex posttranslational modifications of proteins. Emerging evidence has proven that aberrant ppGalNAc-Ts are involved in malignant tumor transformation. However, the exact molecular functions of ppGalNAc-Ts are still unclear. Here, the role of one isoform, ppGalNAc-T4, in breast cancer cell lines was investigated. The expression of ppGalNAc-T4 was found to be negatively associated with migration of breast cancer cells. Loss-of-function studies revealed that ppGalNAc-T4 attenuated the migration and invasion of breast cancer cells by inhibiting the epithelial-mesenchymal transition (EMT) process. Correspondingly, transforming growth factor beta (TGF-β) signaling, which is the upstream pathway of EMT, was impaired by ppGalNAc-T4 expression. ppGalNAc-T4 knockout decreased O-GalNAc modification of TGF-β type Ⅰ and Ⅱ receptor (TβR Ⅰ and Ⅱ) and led to the elevation of TGF-β receptor dimerization and activity. Importantly, a peptide from TβR Ⅱ was identified as a naked peptide substrate of ppGalNAc-T4 with a higher affinity than ppGalNAc-T2. Further, Ser31, corresponding to the extracellular domain of TβR Ⅱ, was identified as the O-GalNAcylation site upon in vitro glycosylation by ppGalNAc-T4. The O-GalNAc-deficient S31 A mutation enhanced TGF-β signaling activity and EMT in breast cancer cells. Together, these results identified a novel mechanism of ppGalNAc-T4-catalyzed TGF-β receptors O-GalNAcylation that suppresses breast cancer cell migration and invasion via the EMT process. Targeting ppGalNAc-T4 may be a potential therapeutic strategy for breast cancer treatment.
Authors: Catharina Steentoft; Sergey Y Vakhrushev; Hiren J Joshi; Yun Kong; Malene B Vester-Christensen; Katrine T-B G Schjoldager; Kirstine Lavrsen; Sally Dabelsteen; Nis B Pedersen; Lara Marcos-Silva; Ramneek Gupta; Eric Paul Bennett; Ulla Mandel; Søren Brunak; Hans H Wandall; Steven B Levery; Henrik Clausen Journal: EMBO J Date: 2013-04-12 Impact factor: 11.598
Authors: Josef Voglmeir; Nicolas Laurent; Sabine L Flitsch; Michael Oelgeschläger; Iain B H Wilson Journal: Comp Biochem Physiol B Biochem Mol Biol Date: 2014-10-23 Impact factor: 2.231
Authors: S M Reddy; C H Barcenas; A K Sinha; L Hsu; S L Moulder; D Tripathy; G N Hortobagyi; V Valero Journal: Br J Cancer Date: 2017-12-12 Impact factor: 7.640