Treatment with Lingqi capsules suppresses colorectal cancer by inhibiting the hepatocyte growth factor/c‑Met signal transduction pathway.

Lingqi capsules (LQCs) are commonly used in Chinese herbal medicine to support the immune system and inhibit tumor growth. The capsules are considered to have a direct effect on tumor cell proliferation and support tumor cell apoptosis. In the present study, the effects of LQC serum on the colorectal cancer cell line, LoVo, and on tumors induced by the cell line were investigated in nude mice. LQC serum was generated by feeding Wistar rats LQC and isolating the serum from blood samples obtained from the rats. The serum was then used to treat LoVo cells for 24, 48 and 72 h, after which the cell morphology and proliferation were assessed. In addition, nude mice were injected with 0.2 ml LoVo cells subcutaneously to produce tumors. After 24 h, xenografted nude mice were treated with 5.0, 2.5 or 1.25 g/kg/day LQC serum by gavage for 21 days and the tumor growth, morphology, apoptosis of tumor cells and expression profiles of hepatocyte growth factor (HGF) and its receptor, c‑Met, were investigated. Compared with the negative controls, inhibition of cell growth was clearly visible in the LoVo cells treated for 24, 48 and 72 h and this inhibition was enhanced as the exposure time and drug concentration increased. The growth of solid tumors induced by the transplantation of LoVo cells into nude mice was inhibited to differing degrees. Following LQC treatment, the apoptotic rates of the cells were increased, the protein and mRNA expression levels of HGF were downregulated and those of c‑Met were upregulated. These findings suggest that LQC treatment inhibits colorectal cancer by downregulating the HGF/c‑Met signal transduction pathway.