p70S6K activation promotes the transdifferentiation of fibroblasts to myofibroblasts in pterygium tissue growth on the cornea

To investigate the role of p70S6K in the transdifferentiation of fibroblasts to myofibroblasts in pterygium tissue growth on the cornea. Quantitative real-time PCR and immunohistochemistry showed that p70S6K expression was higher in pterygium tissues than in normal conjunctival tissues. Higher p70S6K RNA expression levels were correlated with higher pterygium grades. Additionally, western blot analysis revealed that phosphorylated (activated) p70S6K (p-p70S6K) expression was significantly correlated with alpha-smooth muscle actin (alpha-SMA, a hallmark of transdifferentiation) expression in cultured human pterygium fibroblasts (HPFs). Furthermore, p70S6K knockdown and the specific mTOR inhibitor rapamycin decreased the expression levels of p-p70S6K and alpha-SMA in cultured fibroblasts from grade T3 pterygium. p70S6K activation promotes the transdifferentiation of pterygium fibroblasts to myofibroblasts. Thus, targeting p70S6K may be a useful strategy in the management of pterygium.