Anthocyanins of Black Soybean (cv. Cheongja 3) Induce Autophagy via AMPK Activation in U2OS cells

Abstract

Anthocyanins (ATC) were reported to be able to induce autophagy, but the mechanism of which remains still to be clarified. In U2OS cells, ATC extracted from black soybean (cv. Cheongja 3) induced hallmarks of autophagy such as LC3's punctuate pattern formation and the conversion of LC3‐I to LC3‐II. The induction of autophay was accompanied with phosphorylation of multiple protein kinases including Erk1/2, p38MAPK, JNK, AKT, and AMP‐dependent protein kinase (AMPK). While anthocyanins‐induced autophagy was inhibited by none of each inhibitor of ERK1/2, p38 MAPK, JNK, and AKT, suppression of AMPK by compound C as well as knockdown of AMPK using AMPK siRNA reduced anthocyaninsi‐nduced autophagy. Activation of AMPK by AICAR treatment also induced autophagy. Notably, reduction of autophagy via inhibition of AMPK enhanced anthocyanins‐induced apoptosis. Therefore, it can be suggested that anthocyanins induce autophagy by activation of AMPK, and autophagy may inhibit anthocyanins‐induced apoptosis.This research has been supported by the Biogreen 21 Program (Code#PJ007186), Rural Development Administration Korea.