Ligustilide inhibits the proliferation of human osteoblastoma MG63 cells through the TLR4-ERK pathway

Objective: To study the proapoptotic effect of ligustilide on osteoblastoma (OS) and the relative related molecular mechanism.

Methods and materials: An MTT was used to examine the proliferation of OS cells, and Flow cytometry was used to analyze Apoptosis and the cell cycle. Western blotting was used to detect the signaling pathway of Apoptosis, and immunohistochemical (IH) staining was used to detect the Apoptosis status of OS cells. A TLR4 Inhibitor was used to study the effect of ligustilide on OS.

Results: Ligustilide inhibited OS cell proliferation but had no inhibitory effect on normal bone marrow cells. Flow cytometry results showed that ligustilide induced Apoptosis in OS cells, and the cell cycle was arrested at the M/G2 phase. Western blot results showed that ERK, P53, P21, Caspase 9, Caspase 8 and Caspase 3 were all activated; cytochrome C and Bax increased; and Bcl-2 decreased when OS was treated with ligustilide. When an ERK or Caspase Inhibitor was added to the culture medium, the Apoptosis of OS cells decreased to some degree. When OS cells were pretreated with CLI-095, which is a TLR4 Inhibitor, the percentage of apoptotic cells and cell cycle arrest were both reversed. IH results also showed that ligustilide induced Apoptosis in OS cells, and the effect was blocked by the TLR4 Inhibitor.

Conclusion: Ligustilide selectively inhibited the proliferation of OS cells by inducing Apoptosis, which possibly included endogenous and exogenous Apoptosis through TLR4.