Pancreatic cancer cells require an EGF receptor-mediated autocrine pathway for proliferation in serum-free conditions.
In-vitro and in-vivo studies have shown that autocrine growth factors and receptors are frequently expressed in human malignancies. Few of these studies, however, provide evidence that the identified autocrine pathway is functional. In this study, a functional autocrine growth pathway in pancreatic cancer has been identified using an in-vitro cell culture system. When pancreatic cancer cells were grown without change of medium, proliferation was greater than when either medium was replaced frequently (HPAF, CAPAN-2, PANC-1 or SW1990) or cells were grown in the presence of the EGF receptor tyrosine kinase inhibitor AG1478 or the MEK inhibitor PD098059 (HPAF or CAPAN-2). Activity of extracellular-regulated kinases (ERK) 1 and 2 and c- jun and c- fos mRNA levels were significantly elevated in CAPAN-2 cells cultured continuously in serum-free medium. Collectively, the observations indicate that the EGF receptor and the ERK MAP kinase pathway mediate autocrine signals. In contrast to previous reports, the GRP and IGF-I receptors were shown not to be required for autocrine effects on pancreatic cancer cell proliferation. Autocrine stimulation of the EGF receptor can contribute to sustained mitogenic activity and proliferation of pancreatic cancer cells.
Murphy
L O
LO
Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE 68178, USA.
Cluck
M W
MW
Lovas
S
S
Otvös
F
F
Murphy
R F
RF
Schally
A V
AV
Permert
J
J
Larsson
J
J
Knezetic
J A
JA
Adrian
T E
TE
D002455:Cell Division / Q000502:physiology; D016895:Culture Media, Serum-Free; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism / Q000502:physiology*; D005419:Flavonoids / Q000494:pharmacology; D019886:Gastrin-Releasing Peptide / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000502:physiology; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D011799:Quinazolines; D013379:Substrate Specificity; D018808:Transcription Factor AP-1 / Q000096:biosynthesis / Q000235:genetics; D014407:Tumor Cells, Cultured; D020032:Tyrphostins / Q000494:pharmacology
D016895:Culture Media, Serum-Free; D004791:Enzyme Inhibitors; D005419:Flavonoids; D011799:Quinazolines; D018808:Transcription Factor AP-1; D020032:Tyrphostins; C101044:RTKI cpd; D004815:Epidermal Growth Factor; D007334:Insulin-Like Growth Factor I; D019886:Gastrin-Releasing Peptide; D066246:ErbB Receptors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one