Interleukin 10 blocks matrix metalloproteinase-2 and membrane type 1-matrix metalloproteinase synthesis in primary human prostate tumor lines

Insulin-like growth factor (IGF) I has been shown previously to up-regulate matrix metalloproteinase-2 (MMP-2) production, whereas the interleukin (IL) 10/ IL-10 receptor axis has been found to down-regulate MMP-2 synthesis in tumor cells. In this paper, we showed that IL-10 activation of the IL-10 receptor blocked MMP-2 and membrane type 1 (MT1) -MMP transcription and protein synthesis in nonimmortalized primary human prostate cell strains (i.e., HPCA-10a and HPCA-10c) derived from high-grade cancer. Northern blots, Western blots, and ELISAs showed that IL-10 suppressed IGF-I induction of MMP-2 and MT1-MMP mRNA synthesis in these cell strains (P < 0.001). Inhibition studies with IL-10 and IGF-I receptor antibodies plus transfections experiments with IL-10 sense, and IGF-I receptor antisense constructs confirmed these results. Finally, transient transfection experiments and chloramphenicol acetyltransferase assays with different regions of the 5' promoter region of the MMP-2 gene (-1659 to -555 bp) additionally showed that IGF-I stimulated p53-dependent plasmid catecholamine acetyltransferase activity and that IL-10 blocked IGF-I-induced plasmid catecholamine acetyltransferase activity. Electrophoretic mobility shift assays revealed that IL-10 induced protein(s) binding to a putative "silencer element" (-1309 to -555 fragment) downstream of the p53 binding site (-1649 to -1640). The data show that IL-10 blocks IGF-I activation of MMP-2 and MT1-MMP mRNA expression and protein synthesis in primary prostate cell strains.