Chrysin overcomes TRAIL resistance of cancer cells through Mcl-1 downregulation by inhibiting STAT3 phosphorylation

Kriengsak Lirdprapamongkol*, Hiroaki Sakurai, Sherif Abdelhamed, Satoru Yokoyama, Sirivan Athikomkulchai, Amornrat Viriyaroj, Suresh Awale, Somsak Ruchirawat, Jisnuson Svasti, Ikuo Saiki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

68 Scopus citations

Abstract

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively kills various types of cancer cells without harming normal cells, but TRAIL resistance has been frequently observed in cancer cells. Propolis (bee glue) is a material collected from various plants by honeybees and is a rich source of bioactive compounds, including the natural flavonoid chrysin, which possesses multiple anticancer effects. We investigated the mechanism underlying the TRAIL sensitization effect of chrysin, which is a major constituent of Thai propolis, in human lung and cervical cancer cell lines. Propolis extract and chrysin sensitizes A549 and HeLa human cancer cell lines to TRAIL-induced apoptosis. The TRAIL sensitization effect of chrysin is not mediated by inhibition of TRAIL-induced NF-κB activation or by glutathione depletion. Immunoblot analysis using a panel of anti-apoptotic proteins revealed that chrysin selectively decreases the levels of Mcl-1 protein, by downregulating Mcl-1 gene expression as determined by qRT-PCR. The contribution of Mcl-1 in TRAIL resistance was confirmed by si-Mcl-1 knockdown. Among signaling pathways that regulate Mcl-1 gene expression, only constitutive STAT3 phosphorylation was suppressed by chrysin. The proposed action of chrysin in TRAIL sensitization by inhibiting STAT3 and downregulating Mcl-1 was supported by using a STAT3-specific inhibitor, cucurbitacin-I, which decreased Mcl-1 levels and enhanced Key words: tumor necrosis factor-related apoptosis-inducing ligand, STAT3, apoptosis, propolis, natural products TRAIL-induced cell death, similar to that observed with chrysin treatment. In conclusion, we show the potential of chrysin in overcoming TRAIL resistance of cancer cells and elucidate its mechanism of action.

Original languageEnglish
Pages (from-to)329-337
Number of pages9
JournalInternational Journal of Oncology
Volume43
Issue number1
DOIs
StatePublished - 2013/07

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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