Proteasome inhibitor interacts synergistically with autophagy inhibitor to suppress proliferation and induce apoptosis in hepatocellular carcinoma

Authors

  • Bo Hui MD,

    1. Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
    2. Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, China
    3. Department of Surgery, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
    Search for more papers by this author
  • Ying-Hong Shi MD,

    1. Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
    2. Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, China
    Search for more papers by this author
    • The first 3 authors contributed equally to this article.

  • Zhen-Bin Ding MD,

    1. Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
    2. Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, China
    Search for more papers by this author
    • The first 3 authors contributed equally to this article.

  • Jian Zhou MD,

    1. Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
    2. Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, China
    3. Institute of Biomedical Sciences, Fudan University, Shanghai, China
    Search for more papers by this author
  • Cheng-Yu Gu MD,

    1. Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
    2. Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, China
    Search for more papers by this author
  • Yuan-Fei Peng MD,

    1. Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
    2. Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, China
    Search for more papers by this author
  • Hua Yang MD,

    1. Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
    2. Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, China
    Search for more papers by this author
  • Wei-Ren Liu MD,

    1. Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
    2. Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, China
    Search for more papers by this author
  • Guo-Ming Shi MD,

    1. Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
    2. Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, China
    Search for more papers by this author
  • Jia Fan MD

    Corresponding author
    1. Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Shanghai, China
    2. Key Laboratory of Carcinogenesis and Cancer Invasion (Fudan University), Ministry of Education, China
    3. Institute of Biomedical Sciences, Fudan University, Shanghai, China
    • Department of Liver Surgery, Liver Cancer Institute, Zhongshan Hospital, Fudan University, 180 FengLin Road, Shanghai, 200032, China
    Search for more papers by this author
    • Fax: (011) 86-21-64037181


Abstract

BACKGROUND:

The ubiquitin-proteasome system and autophagy-lysosome system are 2 major protein degradation pathways in eukaryotic cells, which are tightly linked to cancer. Proteasome inhibitors have been approved in clinical use against hematologic malignancies, but their application in solid tumors is uncertain. Moreover, the role of autophagy after proteasome inhibition is controversial.

METHODS:

Two proteasome inhibitors, 2 autophagy inhibitors, and 3 hepatocellular carcinoma (HCC) cell lines were investigated in the current study. In vitro, cell proliferation was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cell apoptosis was evaluated by flow cytometry analysis of annexin-V/propidium iodide staining, and autophagy was evaluated by green fluorescent protein-light chain 3 (GFP-LC3) redistribution and LC3 Western blot analysis. In vivo, Ki-67 staining was used to detect cell proliferation, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining was used to detect apoptosis, and electron microscopy and p62 immunohistochemical staining were used to detect autophagy.

RESULTS:

Proteasome inhibitors suppressed proliferation, induced apoptosis, and activated autophagy in HCC cell lines in vitro, and autophagy exerted a protective role after proteasome inhibition. In vivo, anticancer effects of bortezomib on the MHCC-97H orthotopic model (human HCC cells) were different from the effects observed on the Huh-7 subcutaneous model (human HCC cells). The autophagy inhibitor chloroquine interacted synergistically with bortezomib to suppress proliferation and induce apoptosis in both tumor models.

CONCLUSIONS:

The current results indicated that simultaneous targeting of the proteasome and autophagy pathways may represent a promising method for HCC treatment. Cancer 2012. © 2012 American Cancer Society.

Ancillary