The carbon monoxide-releasing molecule CORM-2 inhibits the inflammatory response induced by cytokines in Caco-2 cells

Background and purpose: Recent evidence indicates that carbon monoxide-releasing molecules ( CO-RMs) exhibit potential anti-inflammatory properties. In the present study, we have investigated whether tricarbonyl dichloro ruthenium( II) dimer ( CORM-2) can control the inflammatory response induced by cytokines in a human colonic epithelial cell line, Caco-2. Experimental approach: Caco-2 cells were preincubated with CORM-2 for 30 minutes and then stimulated with interleukin ( IL)-1b, tumor necrosis factor-alpha and interferon-gamma for different times. Gene expression was analyzed by real-time PCR. Protein expression was investigated by Western blot and ELISA. Transcription factor activation was determined by the luciferase method. Key results: We have shown that CORM-2 significantly decreased the mRNA expression of nitric oxide synthase-2 ( NOS-2) and the production of nitrite, in Caco-2 cells stimulated with cytokines. IL-8, IL-6 and metalloproteinase-7 ( MMP-7) mRNA and protein were also significantly reduced by CORM-2. Time-course and small interfering RNA studies suggest that inhibition of IL-6 plays a role in the regulation of MMP-7 expression by CORM-2. These effects of CORM-2 can be dependent on the modulation of nuclear factor-kappa B ( NF-kappa B), activator protein-1, CCAT/enhancer binding protein and the phosphorylated forms of NF-kappa B inhibitory protein-alpha, c-Jun N-terminal protein kinase 1/2, p38 and extracellular signal-regulated kinase 1/2. Conclusions and Implications: CORM-2 can regulate a number of genes relevant in intestinal inflammation and cancer progression. These findings provide new insights into the anti-inflammatory properties and potential applications of this class of compounds.