Background: The newly-synthesized naftopidil analog HUHS1015 suppresses tumor growth and induces apoptosis of cells from a variety of cancer types. The present study was conduced to assess the effect of HUHS1015 on human colonic cancer cells and to clarify the underlying mechanism.
Results: HUHS1015 reduced cell viability of Caco-2 and CW2 human colonic cancer cell lines in a concentration (0.3-100 mM)-dependent manner. HUHS1015 increased terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells in both cell lines. In flow cytometry using propidium iodide and annexin V, HUHS1015 significantly increased the populations of cells undergoing primary necrosis, early apoptosis, and late apoptosis/secondary necrosis in both cell lines. In the cell-cycle analysis, HUHS1015 increased the proportion of the sub-G1 phase of cell, which corresponds to apoptotic cells. HUHS1015 perturbed the mitochondrial membrane potential and reduced the intracellular ATP level. HUHS1015 activated caspases 3, -4, -8, and -9, particularly caspase-3. HUHS1015 promoted cytochrome c release from the mitochondria. HUHS1015 significantly inhibited tumor growth in mice inoculated with CW2 cells.
Conclusion: HUHS1015 induces necrosis by lowering the intracellular ATP level in association with mitochondrial damage and caspase-dependent apoptosis. This occurs in part by stimulating cytochrome c release from the mitochondria to activate caspase-9 followed by the effector caspase-3, responsible for suppression of colonic cancer proliferation in the mouse xenograft model.
Keywords: HUHS1015; apoptosis; colonic cancer cell; necrosis.
Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.