Comparison of effects of P-coumaric acid and coumarin on colorectal cancer cell line by inducing apoptosis and autophagy.

Objective: Autophagy, as a cellular pathway involved in removing damaged proteins and organelles, performs a vital function in the homeostasis and fate of cells. Natural compounds of coumarin (CO) are found in a variety of herbs. Due to their many medicinal properties, including antitumor and anti-proliferative activity, they are involved in apoptosis and autophagy processes. This investigation desired to analyze the apoptotic and autophagic effects of p-coumaric acid (PCA) and CO on HT-29 cells cultured in fibrin hydrogel.

Materials and methods: Cell viability and apoptotic and autophagic changes were evaluated by MTT assay, Acridine Orange, 4',6-diamidino-2-phenylindole (DAPI), and monodansylcadaverine (MDC) staining. The expression Bax, Bad, Bcl2, Lc3, Beclin-1, P53 and Atg5 was respectively measured by qRT-PCR and Western blotting.

Results: CO (IC50=25 μM) and PCA (IC50=150 μM) had a dose- and time-dependent cytotoxic effect in HT-29 cells. So, the cytotoxic effects of CO were significantly higher than PCA and these differences were also evident in cell morphology investigations. The data illustrated a high expression of pro-apoptotic and pro-autophagic genes and a declined expression of anti-apoptotic and anti-autophagic genes.

Conclusion: CO (that was more potent) and p-coumaric acid-induced autophagy via PI3K/Akt/mTOR and AMPK/mTOR signaling on HT-29 cells.