Growth factors and pancreatic cancer.
Cultured human pancreatic cancer cells produce a number of growth factors, including transforming growth factor-alpha (TGF-alpha). These cells also overexpress the epidermal growth factor (EGF) receptor and exhibit a parallel increase in EGF receptor mRNA levels. TGF-alpha, which binds to the EGF receptor, is more potent than EGF in enhancing the anchorage-independent growth of several pancreatic cancer cell lines, including T3M4 cells. In contrast, EGF is more efficient than TGF-alpha with respect to EGF receptor downregulation and tyrosine phosphorylation in T3M4 cells. Further, T3M4 cells recycle EGF, but markedly degrade TGF-alpha. It is suggested that the production of multiple growth factors, the overexpression of the EGF receptor, the recycling of EGF, and the attenuated ability of TGF-alpha to downregulate the EGF receptor combine to enhance the growth advantage of human pancreatic cancer cells.
Korc
M
M
Department of Medicine, University of California, Irvine 92717.
D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism / Q000502:physiology; D006133:Growth Substances / Q000502:physiology*; D006801:Humans; D010190:Pancreatic Neoplasms / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D016211:Transforming Growth Factor alpha / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology; D014407:Tumor Cells, Cultured / Q000187:drug effects
D006133:Growth Substances; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor; D066246:ErbB Receptors