Zhang et al.: Sapindus Saponin in Colorectal Cancer Cells and Its MechanismThis study explored Sapindus saponins role in the proliferation and metastasis of colorectal cancer cells and its possible mechanism. SW620 cells were divided into 8 groups; control group, Sapindus saponin-low group, Sapindus saponin-middle group, Sapindus saponin-high group, microRNA+negative control group, microRNA-5590-3p group, Sapindus saponin+anti-microRNA-negative control group and Sapindus saponin+anti-microRNA-5590-3p group. Cell proliferation and metastasis were determined using colony formation assay, wound healing assay, 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide assay and transwell assay. MicroRNA-5590-3p expression was detected by quantitative reverse transcription-polymerase chain reaction. Matrix metalloproteinases-2 and matrix metalloproteinases-9 protein levels were examined by Western blot. SW620 cell proliferation inhibition rate and microRNA-5590-3p expression were increased, while colony numbers, invaded cell numbers, wound healing rate, matrix metalloproteinases-2 and matrix metalloproteinases-9 protein levels were decreased in Sapindus saponin-low group, Sapindus saponin-middle group, Sapindus saponin-high group in a dose-dependent manner. Besides, microRNA-5590-3p overexpression increased SW620 cell proliferation inhibition rate, while suppressed colony numbers, invaded cell numbers, wound healing rate, matrix metalloproteinases-2 and matrix metalloproteinases-9 protein levels. Compared with the Sapindus saponin+anti-microRNA-negative control group, SW620 cell proliferation inhibition rate was reduced, while colony numbers, invaded cell numbers, wound healing rate, matrix metalloproteinases-2 and matrix metalloproteinases-9 protein levels were enhanced in the Sapindus saponin+anti-microRNA-5590-3p group. Sapindus saponin could repress colorectal cancer cell proliferation and metastasis by upregulating microRNA-5590-3p.