Original Article | Published:

Platycodin D induces apoptosis and triggers ERK- and JNK-mediated autophagy in human hepatocellular carcinoma BEL-7402 cells

Acta Pharmacologica Sinica volume 36, pages 15031513 (2015) | Download Citation

Subjects

Abstract

Aim:

Platycodin D, the main saponin isolated from Chinese herb Platycodonis Radix, exhibits anticancer activities against various cancer cell lines. Here we evaluated its anticancer action against human hepatocellular carcinoma cells in vitro and in vivo, and elucidated the relationship between platycodin D-induced apoptosis and autophagy.

Methods:

The viability of human hepatocellular carcinoma BEL-7402 cells was evaluated with MTT assay, and the apoptosis was examined using Annexin V/PI and Hoechst 33342 staining assays. Monodansylcadaverine (MDC) staining was used to label autophagic vacuoles. The proteins were detected using Western blot analysis. For studying its anticancer action in vivo, platycodin D (5 and 10 mg· kg−1·d−1) was intraperitoneally injected to BEL-7402-bearing mice for 21 days.

Results:

Platycodin D (5–40 μmol/L) inhibited the cell proliferation in vitro with IC50 values of 37.70±3.99, 24.30±2.30 and 19.70±2.36 μmol/L at 24, 48 and 72 h, respectively. Platycodin D (5–20 μmol/L) dose-dependently increased BEL-7402 cell apoptosis, increased the Bax/Bcl-2 ratio and the levels of cleaved PARP and cleaved caspase-3, and decreased the level of Bcl-2. Furthermore, platycodin D (5–20 μmol/L) induced autophagy in BEL-7402 cells, as evidenced by formation of cytoplasmic vacuoles, increased amounts of LC3-II, and increased numbers of MDC-positive cells. Pretreatment with the autophagy inhibitor chloroquine (5 μmol/L) or BAF (50 nmol/L) significantly enhanced platycodin D-induced proliferation inhibition and apoptosis. Moreover, platycodin D (20 μmol/L) activated the ERK and JNK pathways in BEL-7402 cells, and simultaneous blockage of the two pathways effectively suppressed platycodin D-induced autophagy and enhanced platycodin D-induced apoptosis. In BEL-7402-bearing mice, platycodin D (10 mg·kg−1•d−1) significantly reduced relative tumor volume with decreased body weight.

Conclusion:

Platycodin D not only inhibits the proliferation of BEL-7402 cells but also suppresses BEL-7402 xenograft tumor growth. Platycodin D-induced cell proliferation inhibition and apoptosis are amplified by co-treatment with autophagy inhibitors

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Acknowledgements

This work was supported by the Macao Science and Technology Development Fund (070/2013/A), the Research Fund of University of Macau (MRG008-LJJ2014-ICMS MYRG2015-00091-ICMS-QRCM, and MYRG2015-00101-ICMS-QRCM), and the State Key Laboratory of Drug Research (SIMM1403KF-11).

Author information

Author notes

    • Ting Li
    •  & Xiao-huang Xu

    These authors contributed equally to this work.

Affiliations

  1. State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China

    • Ting Li
    • , Xiao-huang Xu
    • , Zheng-hai Tang
    • , Ya-fang Wang
    • , Chung-hang Leung
    • , Xiu-ping Chen
    • , Yi-tao Wang
    •  & Jin-jian Lu
  2. Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China

    • Dik-lung Ma
  3. State key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China

    • Yi Chen
    •  & Jin-jian Lu

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Correspondence to Jin-jian Lu.

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DOI

https://doi.org/10.1038/aps.2015.99

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