J Cancer 2019; 10(24):6057-6064. doi:10.7150/jca.33704

Research Paper

Dihydroartemisinin Induces Endothelial Cell Autophagy through Suppression of the Akt/mTOR Pathway

Jing Liu1, Yanjun Ren2, Yinglong Hou3, Caiqing Zhang4, Bei Wang5, Xiaorui Li6, Rong Sun7,8, Ju Liu1✉

1. Laboratory of Microvascular Medicine, Medical Research Center, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, Shandong, PR China;
2. Department of Orthopaedics; Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, Shandong, PR China
3. Department of Cardiology; Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, Shandong, PR China
4. Department of Respiratory Medicine; Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, Shandong, PR China
5. Department of Ultrasound, Shandong Provincial Qianfoshan Hospital, the First Hospital Affiliated with Shandong First Medical University, Jinan, Shandong, PR China;
6. Graduate School, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, China;
7. Advanced Medical Research Institute, Shandong University, Jinan, China;
8. The Second Hospital of Shandong University, Jinan, China.

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Citation:
Liu J, Ren Y, Hou Y, Zhang C, Wang B, Li X, Sun R, Liu J. Dihydroartemisinin Induces Endothelial Cell Autophagy through Suppression of the Akt/mTOR Pathway. J Cancer 2019; 10(24):6057-6064. doi:10.7150/jca.33704. Available from http://www.jcancer.org/v10p6057.htm

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Abstract

Aims: Dihydroartemisinin (DHA), a derivative of artemisinin, suppresses angiogenesis by regulating endothelial cell phenotypes. In this study, we investigated the effect of DHA on endothelial cell autophagy and the underlying mechanisms.

Methods: Human umbilical vein endothelial cells (HUVECs) were treated with DHA. Formation of autophagosomes in HUVECs was observed by fluorescence microscope after pcDNA3.1-green fluorescent protein (GFP)-microtubule-associated protein 1 light chain 3 (LC3) plasmids transfection. Dichlorofluorescein diacetate (DCFH-DA) staining was used to detect intracellular reactive oxygen species (ROS). Western blot was performed to detect the protein levels of LC3, p62, beclin 1, autophagy-related protein (Atg) 5, p-Akt (protein kinase B), p-mTOR (mammalian target of rapamycin), p-4E-BP1 (eukaryotic translation initiation factor 4E-binding protein 1), and p-p70S6K (p70 ribosomal S6 kinase).

Results: DHA increased LC3-II and the number of fluorescent GFP-LC3 puncta in HUVECs. Silencing ATG5 by siRNA interference attenuated DHA-induced LC3-II elevation. DHA enhanced ROS production, but pretreatment with antioxidant N-acety-l-cysteine (NAC) failed to reduce DHA-induced autophagy in HUVECs. Pretreatment with PD98059, SP600125 and SB203580, the inhibitors of ERK, JNK, and p38 MAPK, did not reverse autophagy in DHA-treated HUVECs. DHA significantly reduced phosphorylation of Akt, mTOR, p70S6K, 4E-BP1 in HUVECs. Rapamycin, an mTOR antagonist, compromised DHA-induced autophagy.

Conclusion: DHA induces autophagy in HUVECs by inhibition of the Akt/mTOR pathway

Keywords: Dihydroartemisinin, Autophagy, HUVEC, Akt, MTOR