STAT3 activation attenuates cancer stem cells elimination effects of resveratrol.

(A) Western blot assays showed the expression of STAT3 and CD133 in the constitutively activated STAT3 infected osteosarcoma cells, which were treated with or without resveratrol. GAPDH was used as loading control. (B) CCK-8 assays showed that resveratrol failed to inhibit proliferation of STAT3-C-overexpressing cells. (C) The percentage of tumor spheres inhibition was analyzed in the STAT3-C-overexpressing cells and control cells, which was treated with resveratrol of indicated concentration. (D) Resveratrol failed to inhibit the growth of STAT3-C-overexpressing subcutaneous xenografts rather than control tumors in NOD/SCID mice. Data represent the means ± SD. *P<0.01.