Nilotinib treatment of patients affected by chronic graft-versus-host disease reduces collagen production and skin fibrosis by down-modulating the TGF-β and p-SMAD pathway.

Abstract The present study was conducted to investigate cellular and molecular features of chronic graft-versus-host disease fibroblasts (GVHD-Fbs) and to assess the effectiveness of Nilotinib as a fibrosis modulator. Growth kinetics, phenotype and differentiation of cultured skin biopsy-derived GVHD-Fbs were compared to normal fibroblasts from both a dermal cell line (n-Fbs) and healthy individuals undergoing cosmetic surgery (n-skin-Fbs). Collagen genes (COL1α1/COL1α2) and p-SMAD2 expression were assessed by Real-Time PCR and immunofluorescence. The in vivo effects of Nilotinib on cGVHD-affected skin were investigated by immunohistochemistry; the relationship to TGF-β plasma levels was assessed. Although the morphology, phenotype and differentiation of cultured GVHD-Fbs were comparable to normal fibroblasts, growth was slower and senescence was reached earlier. The expression of COL1α1 and COL1α2 mRNAs was respectively 4 and 1.6 times higher in cGVHD-Fbs (p=0.02); the addition of TGF-β increased n-Fbs, but not GVHD-Fbs, collagen gene expression. Compared to the baseline, the addition of 1μM Nilotinib induced 86.5% and 49% reduction in COL1α1 and COL1α2 expression in cultured GVHD-Fbs, respectively (p In general, the data show that cGVHD fibroblasts promote fibrosis through abnormal collagen production induced by hyperactive TGF-β signaling. TGF-β inhibition at intracellular and systemic level represents an essential anti-fibrotic mechanism of Nilotinib in clinical setting.