Mol Cancer Res
Center of Molecular Biomedicine, Institute of Biochemistry and Biophysics, Friedrich-Schiller-University Jena, Hans-Knöll-Strasse 2, D-07745 Jena, Germany.
Published: May 2010
The atypical protein kinase Czeta (PKCzeta) was recently shown to mediate epidermal growth factor (EGF)-induced activation of extracellular signal-regulated kinase (ERK) in head and neck squamous carcinoma (HNSCC) cells. Here, it is shown that EGF may induce tyrosine phosphorylation of PKCzeta in several HNSCC cells, breast carcinoma cells, as well as mouse embryonic fibroblasts. In COS-7 cells overexpressing EGF receptor (EGFR) and PKCzeta as a tumor cell model, we show that PKCzeta tyrosine phosphorylation by EGF is induced by catalytic activation. Using a loss-of-function mutant of PKCzeta, we can show that the tyrosine residue 417 in PKCzeta plays an important role in both PKCzeta activation and the ability of PKCzeta to mediate activation of ERK. The importance of PKCzeta in EGF-induced ERK activation can also be shown in several HNSCC and breast carcinoma cell lines as well as in PKCzeta-deficient mouse embryonic fibroblasts. In addition, we present several lines of evidence suggesting the physical association of PKCzeta with EGFR and the importance of the EGFR tyrosine kinase c-Src and the Src-specific phosphorylation site pY845-EGFR in the tyrosine phosphorylation as well as catalytic activation of PKCzeta. This study characterizes PKCzeta as a novel mitogenic downstream mediator of EGFR and indicates PKCzeta as a therapeutic target in some carcinomas.
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http://dx.doi.org/10.1158/1541-7786.MCR-09-0164 | DOI Listing |
Oncogene
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Department of Gastroenterology, Endocrinology and Metabolism, Center for Tumor and Immune Biology, Philipps University Marburg, Marburg, Germany.
The development of resistance remains one of the biggest challenges in clinical cancer patient care and it comprises all treatment modalities from chemotherapy to targeted or immune therapy. In solid malignancies, drug resistance is the result of adaptive processes occurring in cancer cells or the surrounding tumor microenvironment (TME). Future therapy attempts will therefore benefit from targeting both, tumor and stroma compartments and drug targets which affect both sides will be highly appreciated.
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Department of Genetics, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA.
Signaling pathways play key roles in many important biological processes, such as cell division, differentiation, and migration. Phosphorylation site-specific antibodies specifically target proteins phosphorylated on a given tyrosine, threonine, or serine residue. The use of phospho-specific antibodies facilitates the analysis of signaling pathway regulation and activity.
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School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515, China.
: Hepatocellular carcinoma (HCC) remains a significant global health concern, primarily due to the limited efficacy of targeted therapies, which are often compromised by drug resistance and adverse side effects. : In this study, we utilized a Tandem Mass Tag (TMT)-based quantitative proteomic approach to analyze global protein expression and serine/threonine/tyrosine (S/T/Y) phosphorylation modifications in HepG2 cells following treatment with three clinically relevant hepatocellular carcinoma-targeted agents: apatinib, regorafenib, and lenvatinib. : Utilizing KEGG pathway enrichment analysis, biological process enrichment analysis, and protein interaction network analysis, we elucidated the common and specific metabolic pathways, biological processes, and protein interaction regulatory networks influenced by three liver cancer therapeutics.
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January 2025
MOE Key Laboratory of Biosystems Homeostasis & Protection, and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China; Center for Life Sciences, Shaoxing Institute, Zhejiang University, Shaoxing, Zhejiang 321000, China; Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310058, China; The Second Affiliated Hospital, Zhejiang University, Hangzhou, Zhejiang 310009, China. Electronic address:
Transforming growth factor β (TGF-β) is well known to play paradoxical roles in tumorigenesis as it has both growth-inhibitory and pro-metastatic effects. However, the underlying mechanisms of how TGF-β drives the opposing responses remain largely unknown. Here, we report that ERBB4, a member of the ERBB receptor tyrosine kinase family, specifically promotes TGF-β's metastatic response but not its anti-growth response.
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Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK.
Despite their high clinical relevance, obtaining structural and biophysical data on transmembrane proteins has been hindered by challenges involved in their expression and extraction in a homogeneous, functionally-active form. The inherent enzymatic activity of receptor tyrosine kinases (RTKs) presents additional challenges. Oncogenic fusions of RTKs with heterologous partners represent a particularly difficult-to-express protein subtype due to their high flexibility, aggregation propensity and the lack of a known method for extraction within the native lipid environment.
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