Keloid-derived fibroblasts are refractory to Fas-mediated apoptosis and neutralization of autocrine transforming growth factor-β1 can abrogate this resistance

T Chodon, T Sugihara, HH Igawa, E Funayama… - The American journal of …, 2000 - Elsevier
T Chodon, T Sugihara, HH Igawa, E Funayama, H Furukawa
The American journal of pathology, 2000Elsevier
The pathogenesis of keloid remains poorly understood. As no effective therapy for keloid is
as yet available, an insight into its pathogenesis may lead to novel approaches. Apoptosis
has been found to mediate the decrease in cellularity during the transition between
granulation tissue and scar. Here, we report that in contrast to hypertrophic scar-derived and
normal skin-derived fibroblasts, keloid-derived fibroblasts are significantly resistant to both
Fas-mediated and staurosporine-induced apoptosis. The caspases-3,− 8, and− 9 were not …
The pathogenesis of keloid remains poorly understood. As no effective therapy for keloid is as yet available, an insight into its pathogenesis may lead to novel approaches. Apoptosis has been found to mediate the decrease in cellularity during the transition between granulation tissue and scar. Here, we report that in contrast to hypertrophic scar-derived and normal skin-derived fibroblasts, keloid-derived fibroblasts are significantly resistant to both Fas-mediated and staurosporine-induced apoptosis. The caspases-3, −8, and −9 were not activated indicating that the block in the apoptotic pathway in keloid is upstream of the caspases. There were no significant differences in the level of expression of Fas, Bcl-2, and Bax between the three groups but addition of transforming growth factor (TGF)-β1 significantly inhibited Fas-mediated apoptosis in hypertrophic scar-derived and normal skin-derived fibroblasts and neutralization of autocrine TGF-β1 with anti-TGF-β1 antibody abrogated the resistance of keloid-derived fibroblasts. Anti-apoptotic activity was not observed with TGF-β2. This is the first study linking refractory Fas-mediated apoptosis to cellular phenotype in keloids and indicating a pivotal role for the anti-apoptotic effect of TGF-β1 in this resistance. Hence, it becomes important to treat keloids as a separate entity different from hypertrophic scars and enhancement of Fas-sensitivity could be a promising therapeutic target.
Elsevier