IL-10 inhibition of human prostate PC-3 ML cell metastases in SCID mice: IL-10 stimulation of TIMP-1 and inhibition of MMP-2/MMP-9 expression

Invasion Metastasis. 1997;17(2):62-74.

Abstract

The molecular mechanism by which IL-10 inhibits metastases was examined using a SCID mouse model. Human PC-3 ML subclones normally metastasize to the lumbar vertebrae (approximately 70% mice injected, n = 14/20) following intravenous injection in severe combined immunodeficient (SCID) mice. IL-10 treatment of the PC-3 ML cells (15 ng/ml for 36 h) and the SCID mice (0.03 mg/kg/day for 30 days) reduced the number of metastases to 5% of the mice (n = 1/20). More importantly, following discontinuation of IL-10 treatment on day 30, the mice remained tumor-free and mouse survival rates increased dramatically (from < 30% in untreated mice) to about 85% in IL-10-treated mice. IL-10 did not appear to alter the growth rates or colony-forming ability of the PC-3 ML cells in vitro. Likewise, the growth of subcutaneous tumors and established bone marrow metastases was not inhibited by IL-10 treatment of the SCID mice. However IL-10 may inhibit the production of matrix metalloproteases (MMP) and prevent the establishment of metastasis. We therefore examined the influence of IL-10 on PC-3 ML production of MMP-2/MMP-9 and the tissue inhibitors of metalloproteinases (TIMP-1/2). Enzyme-linked immunosandwich assays (ELISAs) revealed that IL-10 (15 ng/ml for 36 h) treatment of the PC-3 ML cells down-regulated MMP-2 and MMP-9 while up-regulating TIMP-1 (not TIMP-2) expression. Likewise, IL-10-treated mice exhibited similar changes in TIMP-1 and MMP-2/MMP-9 expression. The IL-10 effects were blocked by IL-10 receptor antibodies. In comparison to IL-10, IL-4 failed to influence metastasis or the expression of TIMP-1, TIMP-2, MMP-2 and MMP-9 by PC-3 ML cells. We suggest that IL-10-regulated increases in the molar ratio of TIMP-1/MMP-9 and TIMP-2/MMP-2 might inhibit processes critical to the establishment of bone marrow metastasis.

MeSH terms

  • Animals
  • Bone Neoplasms / secondary*
  • Collagenases / drug effects*
  • Collagenases / metabolism
  • Gelatinases / drug effects*
  • Gelatinases / metabolism
  • Humans
  • Interleukin-10 / pharmacology*
  • Male
  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 9
  • Metalloendopeptidases / drug effects*
  • Metalloendopeptidases / metabolism
  • Mice
  • Mice, SCID
  • Neoplasm Proteins / drug effects*
  • Neoplasm Proteins / metabolism
  • Prostatic Neoplasms / metabolism
  • Prostatic Neoplasms / pathology*
  • Survival Analysis
  • Tissue Inhibitor of Metalloproteinase-1 / drug effects*
  • Tissue Inhibitor of Metalloproteinase-1 / metabolism
  • Tumor Cells, Cultured

Substances

  • Neoplasm Proteins
  • Tissue Inhibitor of Metalloproteinase-1
  • Interleukin-10
  • Collagenases
  • Gelatinases
  • Metalloendopeptidases
  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 9