α-Solanine inhibits growth and metastatic potential of human colorectal cancer cells

Solanum nigrum L. (Longkui) is one the most widely used anticancer herbs in traditional Chinese medicine. α-Solanine is an important ingredient of S. nigrum L. and has demonstrated anticancer properties in various types of cancer. However, the effects of α-solanine on colorectal cancer remain elusive. The aim of the present study was to assess the effects of α-solanine on human colorectal cancer cells. The results demonstrated that α-solanine inhibited the proliferation of RKO cells in a dose- and time-dependent manner. In addition, α-solanine arrested the cell cycle at the G0/G1 phase and suppressed the expression levels of cyclin D1 and cyclin-dependent kinase 2 in RKO cells. α-Solanine induced apoptosis of RKO cells, as indicated by morphological changes and positive Annexin-FITC/propidium iodide staining. Additionally, α-solanine activated caspase-3, −8 and −9 in RKO cells, which contributed to α-solanine-induced apoptosis. α-Solanine also increased the generation of reactive oxygen species, which contributed to caspase activation and induction of apoptosis. α-Solanine inhibited the migration, invasion and adhesion of RKO cells, as well as the expression levels and activity of matrix metalloproteinase (MMP)-2 and MMP-9. In addition, α-solanine inhibited cell proliferation, activated caspase-3, −8 and −9, induced apoptosis, and inhibited the migration and invasion of HCT-116 cells. Furthermore, α-solanine inhibited tumor growth and induced apoptosis in vivo. These findings demonstrated that α-solanine effectively suppressed the growth and metastatic potential of human colorectal cancer.