Colorectal cancer (CRC) is the second leading cause of cancer-related death globally.In spite of the increasing knowledge on molecular characteristics of different cancer types including CRC, there is limitation in the development of an effective treatment.The present study aimed to verify the antitumor effect of kopsanone, an indole alkaloid. To achieve this, we treated human colon cancer cells (Caco-2 and HCT-116) with kopsanone and analyzed its effects on cell viability, cell-cell adhesion, and actin cytoskeleton organization. In addition, functional assays including micronuclei formation, colony formation, cell migration, and invasiveness were performed. We observed that kopsanone reduced viability and proliferation and induced micronuclei formation of HCT-116 cells. Also, kopsanone inhibited anchorage-dependent colony formation and modulated adherens junctions (AJs), thus increasing the localization of E-cadherin and β-catenin in the cytosol of the invasive cells. Finally, fluorescence assays showed that kopsanone decreased stress fibers formation and reduced migration but not invasion of HCT-116 cells. Taken together, these findings indicate that kopsanone reduces proliferation and migration of HCT-116 cells via modulation of AJs and can therefore be considered for future in vivo and clinical investigation as potential therapeutic agent for treatment of CRC.