【Objective】To study the growth inhibitory effects and its potential molecular mechanism of nordihydroguaiaretic acid on human osteosarcoma Mg63 cells. 【Methods】 Effects of nordihydroguaiaretic acid on proliferation

cell cycle progression in osteosarcoma Mg63 cells

and involvement of mTORC1 signaling in this process were examined by MTT assay

colony formation assay

flow cytometry

and Western blot analysis. 【Results】 Nordihydroguaiaretic acid inhibited Mg63 cell proliferation

colony formation dose and time-dependently

induced G0/ G1 arrest in osteosarcoma MG63 cells. The 72 h IC50 value of nordihydroguaiaretic acid for Mg63 was (48 ± 2) μmol/L. 10

20

and 50 μmol/L nordihydroguaiaretic acid inhibited the colony formation obviously. The protein level of downstream target of mTORC1 phosphorylation of S6 and 4E-BP1 was down-regulated. 【Conclusion】Nordihydroguaiaretic acid is a promising agent for treatment of osteosarcoma and mTORC1 signaling may contribute to its growth inhibitory effects on osteosarcoma cells.