Background: In recent years, there is an increasing interest in using Traditional Chinese Medicine (TCM) and their patents for the treatment of cancers. Qigefang (QGF) is a TCM formula and has been used for the treatment of metastatic esophageal cancer in China. However, its therapeutic effect on tumors and its mechanism of action is largely unknown. The aim of this study is to explore the role of QGF in the treatment of metastasis of Esophageal Squamous Cell Carcinoma( ESCC).

Methods: Human esophageal carcinoma cell line KYSE150 was used for this study. CCK-8 assay was used to determine the cytotoxicity of QGF. The KYSE150 cells were treated with QGF to determine its effect on cell migration (cell scratch assay and imaging) and invasion (Transwell system based with Matrigel assay). Western blotting was used to investigate the effect of QGF on relevant molecules of signaling pathways. A mouse model of lung metastasis of esophageal cancer was established by injecting the KYSE150-Luc cells through the tail vein. A small animal imaging system was used to observe tumor metastasis in the mice.

Results: QGF reduced cell migration and invasion of KYSE150 cells. QGF significantly inhibited lung metastasis in nude mice. Further study revealed that the expression of Growth arrest-specific 6 (Gas6), Anexelekto (Axl), N-Nuclear factor-kappa B (NF-κB) and matrix metalloproteinase-9 (MMP-9) proteins were decreased both in vitro and in vivo upon treatment with QGF.

Conclusion: QGF could prevent invasion and metastasis of esophageal cancer by inhibiting the Gas6/Axl signaling pathway.