Benzylidenetetralones, cyclic chalcone analogues, induce cell cycle arrest and apoptosis in HCT116 colorectal cancer cells
Colorectal cancer is the third most common cancer in the world, with 1.2 million new cancer cases annually. Chalcones are secondary metabolite precursors of flavonoids that exhibit diverse biological activities, including antioxidant and antitumor activities. The aim of this study was to investigate the antiproliferative effect of new synthetic chalcone derivatives on HCT116 cells. (E)-2-(2′,4′-dimethoxybenzylidene)-1-tetralone (Q705) was found to be the most active (IC50 = 3.44 ± 0.25 μM). Based on these results, this compound was chosen for further analysis of its biochemical and molecular mechanisms. Our results showed that Q705 inhibited the growth and clonogenicity of HCT116 cells. The results of a flow cytometric analyses suggested that this compound caused a significant cell cycle arrest in G2/M phase and increased the proportion of cells in the subG0/G1 phase, marker of apoptosis. Q705-induced apoptosis was confirmed by TdT-mediated dUTP nick end labelling (TUNEL) assay. Treatment of HCT116 cells with this chalcone significantly increased the caspase-3,-7 activity and resulted in cleavage of poly-ADP-ribose polymerase (PARP). Changes in the nuclear morphology such as chromatin condensation were also observed. These effects were associated with a decreased expression of bcl-xL and increased overall ratio of bax/bcl-xL mRNA levels. Immunofluorescence and qRT-PCR analysis revealed that Q705 induced H2AX histone modifications characteristic of DNA damage, disruption of microtubule organization and downregulation of tubulins. In summary, these results suggest that the cyclic chalcone analogue Q705 has potential as a new compound for colorectal cancer therapy.
KeywordsBenzylidenetetralones Cyclic chalcone analogues Cell cycle arrest Apoptosis Colorectal cancer cells
polymerase chain reaction
quantitative reverse transcription PCR
terminal deoxynucleotidyl transferase
This work was supported by SEPO-II (ITMS code: 26220120039) and European Regional Development Fund—Project FNUSA-ICRC (No. CZ.1.05/1.1.00/02.0123). We would like to thank Elisa Caiola and Laura Carrassa for technical support and Tom Billingham for his careful proof-reading of the manuscript.
Conflict of interest
- 2.Figueredo A, Coombes ME, Mukherjee S. Adjuvant therapy for completely resected stage II colon cancer. Cochrane Database Syst Rev. 2008:CD005390.Google Scholar
- 5.Kuo YF, Su YZ, Tseng YH, Wang SY, Wang HM, Chueh PJ. Flavokawain B, a novel chalcone from Alpinia pricei Hayata with potent apoptotic activity: involvement of ROS and GADD153 upstream of mitochondria-dependent apoptosis in HCT116 cells. Free Radic Biol Med. 2010;49:214–26.CrossRefPubMedGoogle Scholar
- 8.Tang Y, Li X, Liu Z, Simoneau AR, Xie J, Zi X. Flavokawain B, a kava chalcone, induces apoptosis via up-regulation of death-receptor 5 and Bim expression in androgen receptor negative, hormonal refractory prostate cancer cell lines and reduces tumor growth. Int J Cancer. 2010;127:1758–68.PubMedCentralCrossRefPubMedGoogle Scholar
- 45.Odlo K, Hentzen J. dit Chabert JF, Ducki S, Gani OA, Sylte I, et al. 1,5-Disubstituted 1,2,3-triazoles as cis-restricted analogues of combretastatin A-4: synthesis, molecular modeling and evaluation as cytotoxic agents and inhibitors of tubulin. Bioorg Med Chem. 2008;16:4829–38.CrossRefPubMedGoogle Scholar
- 49.Li GX, Chen YK, Hou Z, Xiao H, Jin H, Lu G, et al. Pro-oxidative activities and dose-response relationship of (-)-epigallocatechin-3-gallate in the inhibition of lung cancer cell growth: a comparative study in vivo and in vitro. Carcinogenesis. 2010;31:902–10.PubMedCentralCrossRefPubMedGoogle Scholar