Garlic oil blocks tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis by inducing phase II drug-metabolizing enzymes.

Lung cancer caused one-quarter of all cancer deaths that was more than other cancers. Chemoprevention is a potential strategy to reducing lung cancer incidence and death, and the effective chemopreventive agents are needed. We investigated the efficacy and mechanism of garlic oil (GO), the garlic product, in the chemoprevention of tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung cancer in A/J mice and MRC-5 cell models in the present study. As a result, it was demonstrated that GO significantly inhibited the NNK-induced lung cancer in vivo and protected MRC-5 cells from NNK-induced cell damage. GO could induce the expressions of the phase II drug-metabolizing enzymes, including NAD(P)H: quinone oxidoreductase 1 (NQO-1), glutathione S-transferase alpha 1 (GSTA1), and antioxidative enzymes heme oxygenase-1 (HO-1). These results supported the potential of GO as a novel candidate agent for the chemoprevention of tobacco carcinogens induced lung cancer.

Paeonol inhibits apoptosis of vascular smooth muscle cells via up-regulation of autophagy by activating class III PI3K/Beclin-1 signaling pathway.

AIMS: The cross talk between autophagy and apoptosis of vascular smooth muscle cells (VSMCs) plays a vital role in the development of atherosclerosis (AS). Paeonol is isolated from the radix of Cortex Moutan with anti-atherosclerotic and anti-apoptosis effects. However, the mechanisms of paeonol on VSMCs apoptosis are still not fully understood. In this study, we aimed to explore whether paeonol could inhibit VSMCs apoptosis though modulating VSMCs autophagy. MATERIALS AND METHODS: The proteins expressions were detected by western blotting. Autophagosomes and apoptoticbody formation in VSMCs was observed by transmission electron microscopy (TEM). VSMCs autophagy was detected by monodansylcadaverine (MDC) staining using fluorescence microscopy, while VSMCs apoptosis was determined by 4',6-diamidino-2-phenylindole (DAPI) and flow cytometry. KEY FINDINGS: We found that paeonol could significantly increase LC3II protein level, decrease p62 and cleaved caspase-3 proteins levels in aorta of AS mice and ox-LDL-injured VSMCs. Paeonol could augment the number of autophagosomes and reduce the amount of apoptotic bodies in ox-LDL-injured VSMCs. Moreover, paeonol obviously induced VSMCs autophagy compared to ox-LDL group and remarkably suppressed VSMCs apoptosis. However, the effects of paeonol on VSMCs apoptosis could be reversed obviously by 3-MA, the autophagy inhibitor. Furthermore, paeonol could activate class III PI3K-Beclin-1 pathway significantly. Gene silencing of either class III PI3K or Beclin-1 could reverse the effects of paeonol on VSMCs autophagy and apoptosis. SIGNIFICANCE: Based on our results, paeonol could induce VSMCs autophagy by activating class III PI3K/Beclin-1 signaling pathway, thus ultimately inhibiting VSMCs apoptosis.

The Anti-atherosclerotic Effect of Paeonol against Vascular Smooth Muscle Cell Proliferation by Up-regulation of Autophagy via the AMPK/mTOR Signaling Pathway.

Introduction: Paeonol (2'-hydroxy-4'-methoxyacetophenone), isolated from moutan cortex, is an active component and has been shown to have anti-atherosclerotic and anti-proliferation effects on vascular smooth muscle cells (VSMCs). However, the possible role of Paeonol in protecting against VSMC proliferation as related to autophagy has yet to be elucidated. Materials and Methods: The athero-protective effects of Paeonol were evaluated in apoE-/- mice. The effects of Paeonol on VSMC proliferation and autophagy were examined by staining α-SMA and LC3II spots in the media layer of apoE-/- mice, respectively. CCK8 and BrdU assays were used to investigate the effects of Paeonol on cell proliferation in vitro. The autophagic levels in VSMCs were evaluated by detecting LC3II accumulation and p62 degradation by immunoblot analysis. To investigate if Paeonol could prevent VSMCs proliferation through autophagy induction, we tested the change in autophagy and cell proliferation by inhibition of autophagy. The levels of the AMPK/mTOR pathway in autophagy regulation were detected by immunoblot analysis. An AMPK inhibitor and si-AMPK transfection in VSMCs was used to confirm whether AMPK activity plays a key role in autophagy regulation of Paeonol. Results:In vivo experiments confirmed that Paeonol restricted atherosclerosis development and decreased the amount of VSMCs in the media layer of apoE-/- mice. Paeonol increased protein levels of LC3II and the presence of autophagosomes in the media layer of arteries, which implies that Paeonol may induce VSMCs autophagy in vivo. Paeonol showed potential in inhibiting ox-LDL-induced proliferation in vitro experiments. Paeonol dose-dependently enhanced the formation of acidic vesicular organelles and autophagosmomes, up-regulated the expression of LC3II and increased p62 degradation. The autophagy inhibitor CQ obviously attenuated Paeonol-induced autophagy and the anti-proliferation effect in VSMCs. In addition, Paeonol induced phosphorylation of AMPK and reduced phosphorylation of mTOR. An AMPK inhibitor reversed the Paeonol-induced p-mTOR/mTOR decrease. Paeonol induced LC3II conversion, increased p62 degradation and inhibited cell proliferation in VSMCs, the effects of which were abolished by si-AMPK. Conclusion: These results imply that Paeonol inhibits proliferation of VSMCs by up-regulating autophagy, and activating the AMPK/mTOR signaling pathway, providing new insights into the anti-atherosclerosis activity of Paeonol.