Expression and activity of SRC regulate interleukin-8 expression in pancreatic adenocarcinoma cells: implications for angiogenesis.
Interleukin-8 (IL-8) is an angiogenic factor that promotes growth of pancreatic tumors. The purpose of this study was to determine if c-Src, a protein tyrosine kinase frequently overexpressed in pancreatic cancer, regulated IL-8 expression and to elucidate the Src-mediated signaling pathways that contribute to angiogenesis in pancreatic adenocarcinoma cells. In a panel of pancreatic cancer cell lines, expression of total and activated Src correlated with IL-8 production. Furthermore, ectopic expression of activated Src in PANC-1 cells with low endogenous Src activity significantly increased IL-8 production (P < 0.005). In contrast, pharmacologic inhibition of endogenous c-Src kinase activity or small interfering RNA-mediated "knockdown" of c-Src expression in L3.6pl cells with high Src expression and activity caused significant decreases in IL-8 production (P < 0.005). Inhibition of c-Src activity resulted in decreased phosphorylation of Akt, p38, and extracellular signal-regulated kinase (Erk)-1/2. Significant (P < 0.005) dose-dependent decreases were observed in IL-8 expression by inhibiting Src-dependent signaling molecules Erk-1/2 and p38 but not phosphatidylinositol 3-kinase. To assess the relevance of Src inhibition to angiogenesis, in vivo gelfoam assays were done. Robust infiltration of vessels was observed in gelfoam saturated with conditioned medium from pancreatic carcinoma cells. This angiogenesis was nearly abrogated in gelfoams saturated with conditioned medium from cells treated with the Src family kinase inhibitor, PP2 (P < 0.001). Thus, c-Src regulates critical "downstream" signaling pathways that contribute to expression of IL-8 in human pancreatic tumor cells, suggesting c-Src may be a target for therapeutic intervention in pancreatic adenocarcinoma.
Trevino
Jose G
JG
Department of Cancer Biology and Surgical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
Summy
Justin M
JM
Gray
Michael J
MJ
Nilsson
Monique B
MB
Lesslie
Donald P
DP
Baker
Cheryl H
CH
Gallick
Gary E
GE
D000230:Adenocarcinoma / Q000098:blood supply* / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000081247:CSK Tyrosine-Protein Kinase; D045744:Cell Line, Tumor; D004318:Doxycycline / Q000494:pharmacology; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016209:Interleukin-8 / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D020935:MAP Kinase Signaling System; D051379:Mice; D008809:Mice, Inbred C3H; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000098:blood supply* / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010770:Phosphotransferases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D034741:RNA, Small Interfering / Q000235:genetics; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D019061:src-Family Kinases
D016209:Interleukin-8; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D010770:Phosphotransferases; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D004318:Doxycycline