The Rho-kinase inhibitor inhibits proliferation and metastasis of small cell lung cancer

The purpose of this study was to investigate the effects of Rho-kinase inhibitor on the growth, proliferation, apoptosis, adhesion, invasion and migration of NCI-H446 small cell lung cancer cells and to explore the underlying molecular mechanisms involved in this process. After treatment to NCI-H446 small cell lung cancer cells with Fasudil, a Rho-kinase inhibitor, cell biological behaviors were observed. Matrix metalloproteinase activity and Western blot assay were used to evaluate underlying molecular mechanisms. The IC50 of Fasudil to NCI-H446 small cell lung cancer cells was approximately 0.86 mg/ml (95% confidence limits: 0.65–1.17 mg/ml). After treatment with 0.75 mg/ml Fasudil, the ability of NCI-H446 small cell lung cancer cells, including growth, proliferation, adhesion, migration, and invasion were decreased, while their apoptosis was increased significantly. On the molecular level, the total amounts of active MMP2 and MMP9 were decreased about 20.5% (P < 0.05) and 57.5% (P < 0.01) respectively. Myosin phosphatase targeting subunit 1 phosphorylation (P-MYPT1) was reduced by 27.9% (P < 0.05). The activation of caspase-3, and PARP cleavage in experimental group were significantly higher than those in normal control group (P < 0.01). Meanwhile, treatment with Fasudil led to a remarkable reduction of the phosphorylated STAT3 (P-STAT3) (P < 0.01). Taken together, our findings show that Fasudil prevents the growth, metastasis and induces apoptosis of NCI-H446 small cell lung cancer cells by inhibiting the Rho/Rho-kinase pathway. Changes in MMP2, MMP9, P-MYPT1, caspase-3, PARP cleavage and P-STAT3 may be one of its molecular mechanisms.