Distinct metastasis accounts for the leading cause of mortality among patients with gastric cancer. The formation of pre-metastatic niche in the target organs provides permissive environments for the adhesion and subsequent growth of metastasized cancer cells. Targeting the pre-metastatic niche is a potential approach to prevent metastasis. Traditional Chinese medicine regimen called Jianpi Bushen therapy (JPBS) has been widely used in clinics to strengthen patients’ abilities to fight cancer. The present work is aimed to study the modulating effect of JPBS on the lungs expressions of Rac1, Cdc42, SDF-1, and FN in a murine gastric cancer model showing spontaneous lung metastasis.

Mice of strain 615 were inoculated with tumor cells derived from mouse forestomach carcinoma (MFC) to induce spontaneous lung metastasis, and were then treated with JPBS, JPBS combined with fluorouracil (5-FU), or 5-FU. Gene and protein expressions of Rac1, Cdc42, SDF-1, and FN in lungs were determined using real-time PCR and immunohistochemistry, respectively. Serum levels of SDF-1 and FN were also measured using ELISA.

Gene and protein expressions of Rac1, Cdc42, SDF-1, and FN were significantly elevated in the lungs of model mice comparing to the counterpart mice received no tumor cell inoculation. JPBS treatment reduced protein expressions of Rac1, Cdc42, SDF-1 and FN in the lungs of model mice. The treatment could also suppress SDF-1 and FN in blood. For serum SDF-1 the level was further lower in model mice treated with combination therapy of JPBS and 5-FU.

The present work identified the potential roles of Rac1, Cdc42, SDF-1 and FN in the early onset of pre-metastatic niche of gastric cancer, and provided insights into the molecular mechanism by which Jianpi Bushen therapy prevent and suppress cancer metastasis.