In Vitro Effect of Cytokines, Inducers, and Inhibitors on the Secretion of MMP-2 and MMP-9 in Hepatocarcinoma Cell Line SK-Hep-1

Abstract

The prognosis of hepatocellular carcinoma (HCC) remains dismal despite any treatment. Matrix metalloproteinases (MMPs) have been researched for their role in tumor invasion and metastasis. Various cytokines, mitogens, growth factors, inducers, and inhibitors control MMP activities. In this article, we investigated the roles of these in the regulation of MMP-2, -9 secretions in HCC. Human HCC SK-Hep-1 was grown in appropriate media. At near confluence, the cells were washed with phosphate-buffered saline and incubated in serum-free media with PMA; TNF-α, IL-1β; lipopolysaccharide; epigallocatechin gallate (EGCG) and doxycycline (Dox) at various doses with and without PMA; a nutrient mixture (NM) containing lysine, proline, ascorbic acid, and EGCG with and without PMA at; and actinomycin D and cycloheximide at different doses. After 24 hours, the media were removed and analyzed. SK-Hep-1 expressed bands corresponding to MMP-2 and MMP-9. TNF-α showed an insignificant effect on MMP-2 at doses below 25 at which dose MMP-2 was virtually blocked and a moderate dose-dependent effect on MMP-9. Interleukin-1β demonstrated an insignificant effect on MMP-2 at doses below 25 at which dose MMP-2 was completely blocked and enhanced effects on MMP-9. Lipopolysaccharide showed dose-dependent inhibition of MMP-2 and MMP-9. EGCG, Dox, and NM, without and with PMA, downregulated the expression of MMP-2 and MMP-9. Actinomycin D and cycloheximide also had dose-dependent inhibitory effects on MMPs. Our results showed that cytokines, mitogens, and inhibitors modulated SK-Hep-1 MMP-2 and MMP-9 secretion, suggesting the clinical use of especially potent and nontoxic MMP inhibitor as the NM in management of HCC.