Modulation of the Anchorage-Independent Phenotype of Human Lung Fibroblasts Obtained from Fibrotic Tissue Following Culture with Retinoid and Corticosteroid

Fibroblast heterogeneity has been documented in fibrotic tissue from lung and skin. Differences have been demonstrated in proliferative rates in fibroblasts derived from fibrotic lung tissue as compared to normal. Fibroblast lines derived from adult fibrotic lung tissue and neonatal normal lung tissue exhibit colony growth in soft agarose culture, whereas fibroblast cell lines from normal adult lung tissue do not. The characteristic of anchorage-independent growth is consistent with the aggressive nature of the disease and with developmental lung growth. In this study, fibrotic lung fibroblasts were exposed to growth and differentiating factors to determine whether the anchorage-independent phenotype can be modulated. The results indicate that treatment of fibrotic lung fibroblasts with retinoic acid, known to modify matrix gene expression and induce differentiation, inhibits the cells ability to form colonies under soft agarose growth. Treatment with all-trans-retinoic acid yielded the greatest effect inhibiting both IPF and neonatal lung fibroblast anchorage-independent growth approximately 90% at 10(-6) M. Treatment of IPF fibroblasts with all-trans-retinoic acid also inhibited corticosteroid-induced colony growth. Modulation of the "fibrotic" fibroblast phenotype through retinoid therapy may prove beneficial as a potential therapeutic strategy.