Tumor cell-mediated induction of the stromal factor stromelysin-3 requires heterotypic cell contact-dependent activation of specific protein kinase C isoforms.
Stromelysin-3 (ST3, MMP-11) has been shown to be strongly overexpressed in stromal fibroblasts of most invasive human carcinomas. However, the molecular mechanisms leading to ST3 expression in nonmalignant fibroblasts remain unknown. The aim of the present study was to analyze the signaling pathways activated in normal pulmonary fibroblasts after their interaction with non-small cell lung cancer (NSCLC) cells and leading to ST3 expression. The use of selective signaling pathway inhibitors showed that conventional and novel protein kinase Cs (PKC) were required for ST3 induction, whereas Src kinases exerted a negative control. We observed by both conventional and real time confocal microscopy that green fluorescent protein-tagged PKCalpha and PKCepsilon, but not PKCdelta, transfected in fibroblasts, accumulate selectively at the cell-cell contacts between fibroblasts and tumor cells. In agreement, RNAi-mediated depletion of PKCalpha and PKCepsilon, but not PKCdelta significantly decreased co-culture-dependent ST3 production. Finally, a tetracycline-inducible expression model allowed us to confirm the central role of these PKC isoforms and the negative regulatory function of c-Src in the control of ST3 expression. Altogether, our data emphasize signaling changes occurring in the tumor microenvironment that may define new stromal targets for therapeutic intervention.
Louis
Krystel
K
INSERM U526, IFR50, Faculté de Médecine Pasteur, 06107 Nice, France.
Guérineau
Nathalie
N
Fromigué
Olivia
O
Defamie
Virginie
V
Collazos
Alejandra
A
Anglard
Patrick
P
Shipp
Margaret A
MA
Auberger
Patrick
P
Joubert
Dominique
D
Mari
Bernard
B
D002448:Cell Adhesion; D002460:Cell Line; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000201:enzymology; D018920:Coculture Techniques; D004789:Enzyme Activation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D053507:Matrix Metalloproteinase 11; D008666:Metalloendopeptidases / Q000096:biosynthesis* / Q000378:metabolism; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology*; D011493:Protein Kinase C / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D015398:Signal Transduction / Q000187:drug effects; D013752:Tetracycline / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007527:Isoenzymes; D049452:Green Fluorescent Proteins; D011493:Protein Kinase C; D053507:Matrix Metalloproteinase 11; D008666:Metalloendopeptidases; D013752:Tetracycline; D013755:Tetradecanoylphorbol Acetate