['Abstract Aims: To investigate the effect of chloride intracellular channel 1 (CLIC1) on the proliferation, migration, and apoptosis of prostate cancer cell lines PC-3 and DU145 and the possible molecular mechanisms.', 'Using the technique of RNA interference, the expression of CLIC1 was downregulated in the PC-3 and DU145 cell lines. MTT assay, Transwell chamber, and flow cytometry were used to determine the effect of CLIC1 on the proliferation, migration, and apoptosis ability of PC-3 and DU145 cells. The levels of phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), ERK1/2, matrix metalloproteinase (MMP)-2, and MMP-9 were examined by western blotting.', 'The results showed that the knockdown of CLIC1 exerts inhibitory effects on the proliferation and migration of PC-3 and DU145 cells. At the same time, the authors found that the knockdown of CLIC1 has no effect on the apoptosis in PC-3 and DU145 cells. Meanwhile, the levels of p-ERK1/2, MMP-2, and MMP-9 were decreased in the CLIC1 small interfering RNA (siRNA) group compared with the control and vector groups.'] Does chloride intracellular channel 1 regulate prostate cancer cell proliferation and migration through the MAPK/ERK pathway?