title: Targeting death receptor TRAIL-R2 by chalcones for TRAIL-induced apoptosis in cancer cells.
abstract: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in cancer cells without toxicity to normal cells. TRAIL binds to death receptors, TRAIL-R1 (DR4) and TRAIL-R2 (DR5) expressed on cancer cell surface and activates apoptotic pathways. Endogenous TRAIL plays an important role in immune surveillance and defense against cancer cells. However, as more tumor cells are reported to be resistant to TRAIL mediated death, it is important to search for and develop new strategies to overcome this resistance. Chalcones can sensitize cancer cells to TRAIL-induced apoptosis. We examined the cytotoxic and apoptotic effects of TRAIL in combination with four chalcones: chalcone, isobavachalcone, licochalcone A and xanthohumol on HeLa cancer cells. The cytotoxicity was measured by MTT and LDH assays. The apoptosis was detected using annexin V-FITC staining by flow cytometry and fluorescence microscopy. Death receptor expression was analyzed using flow cytometry. The decreased expression of death receptors in cancer cells may be the cause of TRAIL-resistance. Chalcones enhance TRAIL-induced apoptosis in HeLa cells through increased expression of  TRAIL-R2. Our study has indicated that chalcones augment the antitumor activity of TRAIL and confirm their cancer chemopreventive properties.
authors.affiliation: Chair and Department of Microbiology and Immunology, Medical University of Silesia in Katowice,  Jordana 19, 41-808 Zabrze, Poland. wkrol@sum.edu.pl.
authors.forename: Ewelina
authors.initials: E
authors.lastname: Szliszka
authors.forename: Dagmara
authors.initials: D
authors.lastname: Jaworska
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Ksek
authors.forename: Zenon P
authors.initials: ZP
authors.lastname: Czuba
authors.forename: Wojciech
authors.initials: W
authors.lastname: Król
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002599:Chalcone / Q000494:pharmacology* / Q000633:toxicity; D004357:Drug Synergism; D006367:HeLa Cells; D006801:Humans; D009369:Neoplasms / Q000378:metabolism*; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000037:antagonists & inhibitors*; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity
chemical_list: D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D011994:Recombinant Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505639:TNFRSF10B protein, human; D002599:Chalcone