STAT3 and osteosarcoma: Immunofluorescence in 143B osteosarcoma reveals that NP at 3 μM decreased the number of p-STAT3–positive cells; Western blot analysis showed that NP treatment markedly blocked STAT3 activation and phosphorylation of STAT3 in both Tyr705 and Ser727 sites in 143B and MG63 osteosarcoma cells (Fig. 3a and b).