Critical Role of Heat Shock Protein 27 in Bufalin-Induced Apoptosis in Human Osteosarcomas: A Proteomic-Based Research

Xian biao Xie, Jun qiang Yin, Li li Wen, Zhen hua Gao, Chang ye Zou, Jin Wang, Gang Huang, Qing lian Tang, Chiara Colombo, Wei ling He, Qiang Jia, Jing nan Shen

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Abstract

Bufalin is the primary component of the traditional Chinese herb "Chan Su". Evidence suggests that this compound possesses potent anti-tumor activities, although the exact molecular mechanism(s) is unknown. Our previous study showed that bufalin inhibited growth of human osteosarcoma cell lines U2OS and U2OS/MTX300 in culture. Therefore, this study aims to further clarify the in vitro and in vivo anti-osteosarcoma effects of bufalin and its molecular mechanism of action. We found bufalin inhibited both methotrexate (MTX) sensitive and resistant human osteosarcoma cell growth and induced G2/M arrest and apoptosis. Using a comparative proteomics approach, 24 differentially expressed proteins following bufalin treatment were identified. In particular, the level of an anti-apoptotic protein, heat shock protein 27 (Hsp27), decreased remarkably. The down-regulation of Hsp27 and alterations of its partner signaling molecules (the decrease in p-Akt, nuclear NF-κB p65, and co-immunoprecipitated cytochrome c/Hsp27) were validated. Hsp27 over-expression protected against bufalin-induced apoptosis, reversed the dephosphorylation of Akt and preserved the level of nuclear NF-κB p65 and co-immunoprecipitated Hsp27/cytochrome c. Moreover, bufalin inhibited MTX-resistant osteosarcoma xenograft growth, and a down-regulation of Hsp27 in vivo was observed. Taken together, bufalin exerted potent anti-osteosarcoma effects in vitro and in vivo, even in MTX resistant osteosarcoma cells. The down-regulation of Hsp27 played a critical role in bufalin-induced apoptosis in osteosarcoma cells. Bufalin may have merit to be a potential chemotherapeutic agent for osteosarcoma, particularly in MTX-resistant groups.

Original languageEnglish
Article numbere47375
JournalPLoS One
Volume7
Issue number10
DOIs
Publication statusPublished - Oct 16 2012

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ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Xie, X. B., Yin, J. Q., Wen, L. L., Gao, Z. H., Zou, C. Y., Wang, J., Huang, G., Tang, Q. L., Colombo, C., He, W. L., Jia, Q., & Shen, J. N. (2012). Critical Role of Heat Shock Protein 27 in Bufalin-Induced Apoptosis in Human Osteosarcomas: A Proteomic-Based Research. PLoS One, 7(10), [e47375]. https://doi.org/10.1371/journal.pone.0047375