Isofraxidin (IF), a natural coumarin compound, has been reported to possess anti-cancer activity in human liver cancer. However, whether IF is involved in the regulation of colorectal cancer tumorigenesis and development has been not well elucidated.

The cell proliferation were assessed by Cell Counting Kit-8 (CCK-8) and colony formation test, respectively. The transwell assays were conducted to estimate cell migration and invasion abilities. Further, cell apoptosis was evaluated by confocal microscopy analysis, flow cytometry detection and TdT-mediated dUTP Nick-End Labeling (TUNEL) method. Western blot were performed to detect the expression of related protein.

Herein, the result indicated that IF remarkably bated cell proliferation in human colorectal cancer cells HT-29 and SW-480 in a dose- and time-dependent manner. In addition, IF treatment showed obvious inhibitory activity to cell colony formation in HT-29 and SW-480 cells. Confocal microscopy analysis and flow cytometry detection revealed that IF dramatically induced cell apoptosis in HT-29 and SW-480 cells compared with the control. And IF markedly decreased the expression of anti-apoptotic protein bcl-2, whereas the expression of pro-apoptotic proteins, including caspase-3, caspase-9 and bax, notably increased in HT-29 and SW-480 cells. Besides, IF blocked Akt pathway via inhibition expression of p-Akt. Furthermore, MK2206, an Akt inhibitor, could inhibit cell colony formation and induced apoptosis. This effect is even more obvious in the presence of MK2206 and IF compared to that of either agent alone.

Together, the present study reports a novel use of IF in mitigating human colorectal cancer proliferation and inducing apoptosis via blockage of Akt pathway.