Abstract
Proliferation of pancreatic stellate cells (PSCs) plays a cardinal role during fibrosis development. Therefore, the suppression of PSC growth represents a therapeutic option for the treatment of pancreatic fibrosis. It has been shown that up-regulation of the enzyme heme oxygenase-1 (HO-1) could exert antiproliferative effects on PSCs, but no information is available on the possible role of carbon monoxide (CO), a catalytic byproduct of the HO metabolism, in this process. In the present study, we have examined the effect of CO releasing molecule-2 (CORM-2) liberated CO on PSC proliferation and have elucidated the mechanisms involved. Using primary rat PSCs, we found that CORM-2 inhibited PSC proliferation at nontoxic concentrations by arresting cells at the G0/G1 phase of the cell cycle. This effect was associated with activation of p38 mitogen-activated protein kinase (MAPK) signaling, induction of HO-1 protein, and up-regulation of the cell cycle inhibitor p21Waf1/Cip1. The p38 MAPK inhibitor 4-(4-flurophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)imidazole (SB203580) abolished the inhibitory effect of CORM-2 on PSC proliferation and prevented both CORM-2-induced HO-1 and p21Waf1/Cip1 up-regulation. Treatment with tin protoporphyrin IX, an HO inhibitor, or transfection of HO-1 small interfering RNA abolished the inductive effect of CORM-2 on p21Waf1/Cip1 and reversed the suppressive effect of CORM-2 on PSC growth. The ability of CORM-2 to induce cell cycle arrest was abrogated in p21Waf1/Cip1-silenced cells. Taken together, our results suggest that CORM-2 inhibits PSC proliferation by activation of the p38/HO-1 pathway. These findings may indicate a therapeutic potential of CO carriers in the treatment of pancreatic fibrosis.
Footnotes
Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org.
doi:10.1124/mol.109.059519.
-
ABBREVIATIONS:
- PSC
- pancreatic stellate cell
- ANOVA
- analysis of variance
- BrdU
- 5-bromo-2′-deoxyuridine
- Cdk
- cyclin-dependent kinase
- CORM
- carbon monoxide-releasing molecule
- CORM-2
- tricarbonyldichlororuthenium(II) dimer
- ERK
- extracellular signal-regulated kinase
- FCS
- fetal calf serum
- GAPDH
- glyceraldehyde 3-phosphate dehydrogenase
- HO-1
- heme oxygenase-1
- IMDM
- Iscove's modified Dulbecco's medium
- JNK
- c-Jun NH2-terminal kinase
- MAPK
- mitogen-activated protein kinase
- SB203580
- 4-(4-flurophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl) imidazole
- siRNA
- small interfering RNA
- SnPP
- tin protoporphyrin IX
- DMSO
- dimethyl sulfoxide
- LDH
- lactate dehydrogenase
- MKK
- mitogen-activated protein kinase kinase
- MAPKAPK
- mitogen-activated protein kinase-activated protein kinase
- SB202474
- 4-ethyl-2-(p-methoxyphenyl)-5-(4′-pyridyl)-1H-imidazole.
- Received July 17, 2009.
- Accepted January 6, 2010.
- Copyright © 2010 The American Society for Pharmacology and Experimental Therapeutics
MolPharm articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|