FAK regulates E-cadherin expression via p-Src(Y416)/p-ERK(1/2)/p-Stat3(Y705) and PPAR(γ)/miR-125b/Stat3 signaling pathway in B16F10 melanoma cells

Focal adhesion kinase (FAK) is involved in tumor cell migration and metastasis. However, the underlying mechanism remains unclear. Here, we present a signaling pathway involved in the regulation of melanoma cell migration by FAK. We found that the interference of FAK expression suppressed B16F10 cell migration/metastasis, and altered the expressions of genes involved in melanoma migration/metastasis. The down-regulation of FAK inhibited the expression of p-Src(Y416), p-ERK(1/2), Stat3 and p-Stat3(Y705), while promoted the expression of PPARγ, miR-125b and E-cadherin. Then we found that FAK inhibited E-cadherin expression via p-Src(Y416)/p-ERK(1/2)/ p-Stat3(Y705) and PPARγ/miR-125b/Stat3 signaling pathway in B16F10 cell. Moreover, miR-125b inhibited B16F10 cell migration. Furthermore, we repeated the key data with human melanoma cell line A375. The results obtained from A375 cells fell in line with those from B16F10 cells. Using Oncomine database, we found that the mRNA levels of FAK, Src, ERK(1/2) and Stat3 increased, while the mRNA levels of PPARγ, C21orf34 (miR-125b host gene) and E-cadherin decreased in human metastatic melanoma. The data from human breast cancer confirmed those from metastatic melanoma. Taken together, our study suggests that down-regulation of FAK promotes E-cadherin expression via p-Src(Y416)/p-ERK(1/2)/p-Stat3(Y705) and PPARγ/miR-125b/Stat3 signaling pathway. Our findings provide a novel explanation regarding how FAK promotes melanoma cell migration, suggesting that FAK might be a potential target for melanoma therapy.