N-acetylglucosaminyltransferase-V (GnT-V) has been reported to be closely associated with tumor migration, but the mechanism has been not currently clear. In this study we found that GnT-V activated EGFR signaling and promoted cell migration through receptor protein tyrosine phosphatase kappa (RPTPkappa). The overexpression of GnT-V gene in human hepatoma SMMC-7721 cell line not only induced the addition of beta1,6 GlcNAc branch to N-glycan of RPTPkappa but also decreased the protein level of RPTPkappa, which both contributed to the decreased phosphatase activity of RPTPkappa activating subsequently EGFR signaling. Moreover, we found that the knockdown of RPTPkappa and its addition of beta1,6 GlcNAc branch both promoted cell migration, which could be ascribed to the activation of EGFR signaling regulated by RPTPkappa. Therefore, our findings could provide an insight into the molecular mechanism of how GnT-V promoted cell migration, suggesting that RPTPkappa could be one of factors regulating the EGF-mediated migration signals.
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http://dx.doi.org/10.1016/j.abb.2009.02.005 | DOI Listing |
IUBMB Life
January 2025
Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
Targeting the influencing factors in tumor growth and expansion in the tumor microenvironment is one of the key approaches to cancer immunotherapy. Various factors in the tumor microenvironment can in cooperation stimulate tumor growth, suppress anti-tumor immune responses, promote drug resistance, and ultimately enhance tumor recurrence. Therefore, due to the dependence and close cooperation of these axes, their combined targeting can have a greater effect compared to their individual targeting.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Pulmonary and Critical Care Medicine, State Key Laboratory of Respiratory Health and Multimorbidity, West China Hospital, Sichuan University, Chengdu 610065, China.
Determining mutations in the kinase domain of the epidermal growth factor receptor (EGFR) is critical for the effectiveness of EGFR tyrosine kinase inhibitors (TKIs) in lung cancer. Yet, DNA-based sequencing analysis of tumor samples is time-consuming and only provides gene mutation information on EGFR, making it challenging to design effective EGFR-TKI therapeutic strategies. Here, we present a new image-based method involving the rational design of a quenched probe based on EGFR-TKI to identify mutant proteins, which permits specific and "no-wash" real-time imaging of EGFR in living cells only upon covalent targeting of the EGFR kinase.
View Article and Find Full Text PDFJ Cell Sci
January 2025
Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15261, USA.
Ligand binding to EGFR activates Rho family GTPases, triggering actin cytoskeleton reorganization, cell migration and invasion. Activated EGFR is also rapidly endocytosed but the role of EGFR endocytosis in cell motility is poorly understood. Hence, we used live-cell microscopy imaging to demonstrate that endogenous fluorescently labeled VAV2, a guanine nucleotide exchange factor for Rho GTPases, is co-endocytosed with EGFR in genome-edited human oral squamous cell carcinoma (HSC3) cells, an in vitro model for head-and-neck cancer where VAV2 is known to promote metastasis and associates with poor prognosis.
View Article and Find Full Text PDFInt J Biol Sci
January 2025
Department of Otolaryngology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, 138, Sheng Li Road, Tainan, Taiwan, 70456.
Results of retinoid-based therapies in head and neck cancer (HNC) are generally disappointing, indicating a lack of understanding of retinoic acid signaling. The role of retinoic acid receptor gamma (RARγ) and its isoforms in HNC is yet to be established. In this study, we found that RARγ1, 2, 4 are the predominant RARγ isoforms expressed in various types of human cancers, including HNC.
View Article and Find Full Text PDFInt J Biol Sci
January 2025
Department of Medical Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China, 610041.
The EGFR-TKIs (epidermal growth factor receptor-tyrosine kinases inhibitors) offer significant benefits to lung cancer patients with sensitive EGFR mutations; however, the development of acquired resistance poses a significant challenge and leads to poor prognosis. Thus, exploring novel therapeutic strategies to overcome EGFR-TKI resistance is urgently needed. This study introduces an innovative approach utilizing folic acid-modified milk exosomes loaded with c-kit siRNA (FA-mExo-siRNA-c-kit) to target EGFR-TKI resistance in lung cancer.
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