BACKGROUND: Keloid scar is a fibroproliferative disorder characterized by increased deposition of extracellular matrix components. Hepatocyte growth factor (HGF), also known as the "scatter factor," and its receptor, a product of the Met oncogene, play multiple roles in regulating cell behavior. However, the role of this system in pathogenic fibrosis is still unclear. Our aim was to investigate and to clarify the role of HGF and its receptor c-Met in pathogenesis of keloid scars. METHODS: This study investigated the expression profile of HGF and c-Met in keloid and normal skin tissue. In addition, the role of normal and keloid keratinocytes in modulating the expression of fibroblast HGF (epithelial-mesenchymal interactions) was examined using a two-chamber serum-free coculture model. The effect of serum stimulation on fibroblast expression of HGF and c-Met was also studied. RESULTS: Increased levels of HGF and c-Met were observed in tissue extracts obtained from keloid tissue. Increased levels of HGF and c-Met localization were observed in the basal epidermis and in the dermis of keloid tissue compared with normal skin. Serum stimulation seemed to upregulate the expression of both HGF and c-Met in fibroblasts. Finally, coculture of keloid keratinocytes with keloid fibroblasts upregulated levels of both HGF and c-Met in keratinocyte cell lysates and conditioned media obtained from fibroblast culture. CONCLUSIONS: These findings emphasize the importance of the HGF/c-Met system in keloid biology and pathogenesis and suggest a possible target for therapeutic intervention in the prevention and treatment of keloids.
BACKGROUND: Keloid scar is a fibroproliferative disorder characterized by increased deposition of extracellular matrix components. Hepatocyte growth factor (HGF), also known as the "scatter factor," and its receptor, a product of the Met oncogene, play multiple roles in regulating cell behavior. However, the role of this system in pathogenic fibrosis is still unclear. Our aim was to investigate and to clarify the role of HGF and its receptor c-Met in pathogenesis of keloid scars. METHODS: This study investigated the expression profile of HGF and c-Met in keloid and normal skin tissue. In addition, the role of normal and keloid keratinocytes in modulating the expression of fibroblast HGF (epithelial-mesenchymal interactions) was examined using a two-chamber serum-free coculture model. The effect of serum stimulation on fibroblast expression of HGF and c-Met was also studied. RESULTS: Increased levels of HGF and c-Met were observed in tissue extracts obtained from keloid tissue. Increased levels of HGF and c-Met localization were observed in the basal epidermis and in the dermis of keloid tissue compared with normal skin. Serum stimulation seemed to upregulate the expression of both HGF and c-Met in fibroblasts. Finally, coculture of keloid keratinocytes with keloid fibroblasts upregulated levels of both HGF and c-Met in keratinocyte cell lysates and conditioned media obtained from fibroblast culture. CONCLUSIONS: These findings emphasize the importance of the HGF/c-Met system in keloid biology and pathogenesis and suggest a possible target for therapeutic intervention in the prevention and treatment of keloids.