Bis-beta-carboline alkaloids are widely distributed in natural products and represent a promising drug-like scaffold for discovering drugs and bioactive molecules. In this study, we utilized the structural simplification strategy to construct a novel bis-beta-carboline scaffold via "one-pot" condensation-Mannich reaction. The simplified bis-beta-carboline derivatives were obtained in good yield. Antitumor evaluation revealed most compounds, especially 3m, displayed potent antitumor activity (IC(50) values for 3m: 0.96 muM approximately 1.52 muM). More importantly, 3m displayed valuable antitumor properties including anti-migration and anti-invasion activity against cancer cells, antiangiogenic and vascular-disrupting properties. Mechanistic studies revealed 3m potently inhibited both Top1 and Top2 activity, thus interfering with DNA synthesis in cancer cells. Taken together, this study developed a new synthetic methodology to construct a novel bis-beta-carboline scaffold, which represents a promising lead structure for antitumor drug discovery. CI - Copyright (c) 2023 Elsevier Inc. All rights reserved.