Azadirone, a limonoid tetranortriterpene, induces death receptors and sensitizes human cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) through a p53 protein-independent mechanism: evidence for the role of the ROS-ERK-CHOP-death receptor pathway.
Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has shown efficacy in a phase 2 clinical trial, development of resistance to TRAIL by tumor cells is a major roadblock. We investigated whether azadirone, a limonoidal tetranortriterpene, can sensitize human tumor cells to TRAIL. Results indicate that azadirone sensitized cancer cells to TRAIL. The limonoid induced expression of death receptor (DR) 5 and DR4 but did not affect expression of decoy receptors in cancer cells. The induction of DRs was mediated through activation of ERK and through up-regulation of a transcription factor CCAAT enhancer-binding protein homologous protein (CHOP) as silencing of these signaling molecules abrogated the effect of azadirone. These effects of azadirone were cancer cell-specific. The CHOP binding site on the DR5 gene was required for induction of DR5 by azadirone. Up-regulation of DRs was mediated through the generation of reactive oxygen species (ROS) as ROS scavengers reduced the effect of azadirone on ERK activation, CHOP up-regulation, DR induction, and TRAIL sensitization. The induction of DRs by this limonoid was independent of p53, but sensitization to TRAIL was p53-dependent. The limonoid down-regulated the expression of cell survival proteins and up-regulated the proapoptotic proteins. The combination of azadirone with TRAIL was found to be additive at concentrations lower than IC50, whereas at higher concentrations, the combination was synergistic. Overall, this study indicates that azadirone can sensitize cancer cells to TRAIL through ROS-ERK-CHOP-mediated up-regulation of DR5 and DR4 signaling, down-regulation of cell survival proteins, and up-regulation of proapoptotic proteins.
From the Cytokine Research Laboratory, Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030,; the Cancer Institute, University of Mississippi Medical Center, Jackson, Mississippi 39216.
Subash C
SC
Gupta
the Organic Chemistry Section, National Institute for Interdisciplinary Science and Technology (CSIR), Trivandrum, 695 019 Kerala, India.
Sajin K
SK
Francis
the Organic Chemistry Section, National Institute for Interdisciplinary Science and Technology (CSIR), Trivandrum, 695 019 Kerala, India.
Mangalam S
MS
Nair
the Cancer Institute, University of Mississippi Medical Center, Jackson, Mississippi 39216.
Yin-Yuan
YY
Mo
From the Cytokine Research Laboratory, Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030,. Electronic address: aggarwal@mdanderson.org.
Bharat B
BB
Aggarwal
D000970:Antineoplastic Agents / Q000494:pharmacology*; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis; D045744:Cell Line, Tumor; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D036701:Limonins / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000235:genetics / Q000378:metabolism*; D020218:Response Elements; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000494:pharmacology*; D051742:Transcription Factor CHOP / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects
D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; C497249:DDIT3 protein, human; D036701:Limonins; D017382:Reactive Oxygen Species; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C487479:azadirone; D051742:Transcription Factor CHOP; D048049:Extracellular Signal-Regulated MAP Kinases
Anticancer Drug; Apoptosis; CHOP; Cancer Therapy; Death Receptor; Limonoid; MAP Kinases (MAPKs); Reactive Oxygen Species (ROS); Trail