Phospholipase D-mediated autophagic regulation is a potential target for cancer therapy
CELL DEATH AND DIFFERENTIATION
Authors: Jang, Y. H.; Choi, K. Y.; Min, D. S.
Abstract
Autophagy is a catabolic process in which cell components are degraded to maintain cellular homeostasis by nutrient limitations. Defects of autophagy are involved in numerous diseases, including cancer. Here, we demonstrate a new role of phospholipase D (PLD) as a regulator of autophagy. PLD inhibition enhances autophagic flux via ATG1 (ULK1), ATG5 and ATG7, which are essential autophagy gene products critical for autophagosome formation. Moreover, PLD suppresses autophagy by differentially modulating phosphorylation of ULK1 mediated by mTOR and adenosine monophosphate-activated protein kinase (AMPK), and by suppressing the interaction of Beclin 1 with vacuolar-sorting protein 34 (Vps34), indicating that PLD coordinates major players of the autophagic pathway, AMPK-mTOR-ULK1 and Vps34/Beclin 1. Ultimately, PLD inhibition significantly sensitized in vitro and in vivo cancer regression via genetic and pharmacological inhibition of autophagy, providing rationale for a new therapeutic approach to enhancing the anticancer efficacy of PLD inhibition. Collectively, we show a novel role for PLD in the molecular machinery regulating autophagy.
MiR-122-5p andmiR-326-3p promote cadmium-inducedNRK-52Ecell apoptosis by downregulatingPLD1
ENVIRONMENTAL TOXICOLOGY
Authors: Yuan, Wenya; Liang, Lixia; Huang, Ke; Deng, Yaotang; Dong, Ming; Wang, Guanghai; Zou, Fei
Abstract
Cadmium is a toxic heavy metal distributed broadly in the environment and manufactory industry. Long-term exposure to cadmium, considered as a risk for kidney injury, leads to chronic kidney disease eventually. Phospholipase D1 (PLD1) promotes cell proliferation and inhibits apoptosis, and might be involved in cadmium-induced kidney injury. In this study, we used miRNA microarray assays and bioinformatics analysis to identify miRNAs, which may regulate PLD1 expression and exert an impact on cadmium-induced kidney injury. MiR-122-5p and miR-326-3p?selected as candidates, were explored for their regulatory functions in kidney injury, using NRK-52E cells. Both of these two miRNAs exhibited higher expression in kidneys of SD rats after exposure to cadmium for 6 weeks. Cadmium treatment also increased miR-122-5p and miR-326-3p and decreased PLD1 in NRK-52E cells. Both of miR-122-5p and miR-326-3p could downregulate PLD1 expression through targeting its 3 ' UTR and enhance cadmium-induced apoptosis, while inhibiting either of these two miRNAs could reverse such effects. In conclusion, our results suggest that miR-122-5p and miR-326-3p might enhance cadmium-induced NRK-52E cell apoptosis through downregulating PLD1 expression.