International Journal of Biological Sciences

Impact factor
3.873

ISSN 1449-2288

News feeds of IJBS published articles
My Manuscript
My Account

Journal of Biomedicinenew

Theranostics

International Journal of Medical Sciences

Journal of Cancer

Oncomedicine

Journal of Genomics

Journal of Bone and Joint Infection (JBJI)

Nanotheranostics

PubMed Central Indexed in Journal Impact Factor

Int J Biol Sci 2014; 10(2):212-224. doi:10.7150/ijbs.8056

Research Paper

Bufalin Induces the Interplay between Apoptosis and Autophagy in Glioma Cells through Endoplasmic Reticulum Stress

Shuying Shen1, Yi Zhang1, Zhen Wang1, Rui Zhang2, Xingguo Gong1✉

1. Institute of Biochemistry, Zhejiang University, Hangzhou, 310058, PR China;
2. Department of Neurosurgery, The First Affiliated Hospital of Nanjing Medical University, No. 300 Guangzhou Road, Nanjing 210029, China.

Abstract

Malignant gliomas are common primary tumors of the central nervous system. The prognosis of patients with malignant glioma is poor in spite of current intensive therapy and thus novel therapeutic modalities are necessary. Bufalin is the major component of Chan-Su (a traditional Chinese medicine) extracts from the venom of Bufo gargarizan. In this study, we evaluated the growth inhibitory effect of bufalin on glioma cells and explored the underlying molecular mechanisms. Our results showed that bufalin inhibited the growth of glioma cells significantly. Mechanistic studies demonstrated that bufalin induced apoptosis through mitochondrial apoptotic pathway. In addition, bufalin was also found to induce ER stress-mediated apoptosis, which was supported by the up- regulation of ER stress markers, CHOP and GRP78, and augmented phosphorylation of PERK and eIF2α as well as cleavage of caspase-4. Downregulation of CHOP using siCHOP RNA attenuated bufalin-induced apoptosis, further confirming the role of ER stress response in mediating bufalin-induced apoptosis. Evidence of bufalin-induced autophagy included formation of the acidic vesicular organelles, increase of autophagolysosomes and LC3-II accumulation. Further experiments showed that the mechanism of bufalin-induced autophagy associated with ATP deleption involved an increase in the active form of AMPK, decreased phosphorylation levels of mTOR and its downstream targets 4EBP1 and p70S6K1. Furthermore, TUDC and silencing of eIF2α or CHOP partially blocked bufalin-induced accumulation of LC3-II, which indicated that ER stress preceded bufalin-induced autophagy and PERK/eIF2α/CHOP signaling pathway played a major part in the process. Blockage of autophagy increased expression of ER stress associated proteins and the ratio of apoptosis, indicating that autophagy played a cytoprotective role in bufalin induced ER stress and cell death. In conclusion, bufalin inhibits glioma cell growth and induces interplay between apoptosis and autophagy through endoplasmic reticulum stress. It will provide molecular bases for developing bufalin into a drug candidate for the treatment of maglinant glioma.

Keywords: ER stress, autophagy, apoptosis, bufalin, glioma cancer.

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) License. See http://ivyspring.com/terms for full terms and conditions.
How to cite this article:
Shen S, Zhang Y, Wang Z, Zhang R, Gong X. Bufalin Induces the Interplay between Apoptosis and Autophagy in Glioma Cells through Endoplasmic Reticulum Stress. Int J Biol Sci 2014; 10(2):212-224. doi:10.7150/ijbs.8056. Available from http://www.ijbs.com/v10p0212.htm