Pharmacological inhibition of gelatinase B induction and tumor cell invasion

The 92 kDa matrix metalloproteinase (gelatinase B, MMP-9) plays a major role in the facilitation of tumor metastasis and in inflammatory disorders characterized by excessive matrix protein destruction. MMP-9 is transcriptionally induced in multiple cell types by exposure to the inflammatory mediators bacterial endotoxin, interleukin-1 (IL-1) or tumor necrosis factor-alpha (TNF-alpha). CT-2519, (1-(5-isothiocyanatohexyl)-3,7-dimethylxanthine), a synthetic small molecule from an anti-inflammatory compound library, was evaluated for its effect on endotoxin and cytokine-induced MMP-9 synthesis by a monocytic leukemic cell line, THP-1, and a monocyte/macrophage line, RAW 264.7. CT-2519 dose-dependently inhibited endotoxin and cytokine-induced synthesis of MMP-9 by these cells. Furthermore, both MMP-9 secretion and matrix invasion by cells of a human fibrosarcoma cell line, HT-1080, were inhibited by CT-2519 in a dose-dependent manner. Northern blot analyses and studies utilizing MMP-9 promoter constructs indicated that the inhibitory action of CT-2519 occurs at the level of transcriptional suppression. Given the observation that cellular activation by endotoxin, IL-1 and TNF-alpha may be mediated, at least in part, through induction of certain species of phosphatidic acid (PA), the effect of CT-2519 on lipid levels was analyzed. CT-2519 effectively reduced endotoxin-mediated increases in particular cellular lipid levels. Pharmacologic modulation of cytokine-dependent gene products, such as MMP-9, may offer an important therapeutic approach to the treatment of neoplastic and inflammatory disorders.