[Shikonin down-regulates CXCR4 expression and inhibits CXCL12-induced migratory responses in colorectal carcinoma cell line SW480].

Objective: To investigate the effects of shikonin on the proliferation, expression of CXCR4 and the migratory responses to CXCL12 in colorectal carcinoma cell line SW480.

Methods: The proliferation of SW480 cells was assessed by MTT assay. Cell surface expression of CXCR4 was determined by flow cytometry. The migratory ability was determined by Transwell.

Results: Shikonin inhibited the proliferation of SW480 cells in time- and concentration-dependent manner. The expression rate of CXCR4 in SW480 cells was 99.1%. After application of shikonin 0.01 micromol/L, 0.1 micromol/L and 1.0 micromol/L for 24 h, the expression rate of CXCR4 decreased to 76.0%, 59.1% and 35.5% respectively (F=1098.041, P <0.001), and the CXCL12-induced SW480 cell migratory inhibition rate was 25.2%, 38.5% and 55.7% respectively (F=48.970, P <0.001).

Conclusion: Besides having inhibiting tumor cell proliferation effect, Shikonin may also play a role in anti-metastasis via down-regulating the expression of CXCR4 and reducing the CXCL12-induced migratory response in colorectal carcinoma cell.