title: TRAIL inactivates the mitotic checkpoint and potentiates death induced by microtubule-targeting agents in human cancer cells.
abstract: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has attracted interest as an anticancer treatment, when used in conjunction with standard chemotherapy. We investigated the mechanistic basis for combining low-dose TRAIL with microtubule-targeting agents that invoke the mitotic checkpoint. Treatment of T98G and HCT116 cells with nocodazole alone resulted in a robust mitotic block with initially little cell death; low levels of cell death were also seen with TRAIL alone at 10 ng/mL final concentration. In contrast, the addition of low-dose TRAIL to nocodazole was associated with maximally increased caspase-3, caspase-8, and caspase-9 activation, which efficiently abrogated the mitotic delay and markedly increased cell death. In contrast, the abrogation of mitotic checkpoint and increased cell death were blocked by inhibitors of caspase-8 and caspase-9 or pan-caspase inhibitor. The addition of TRAIL to either nocodazole or paclitaxel (Taxol) reduced levels of the mitotic checkpoint proteins BubR1 and Bub1. BubR1 mutated for the caspase cleavage sites, but not wild-type BubR1, was resistant to cleavage induced by TRAIL added to nocodazole, and partially blocked the checkpoint abrogation. These results suggest that adding a relatively low concentration of TRAIL to antimicrotubule agents markedly increases complete caspase activation. This in turn accentuates degradation of spindle checkpoint proteins such as BubR1 and Bub1, contributes to abrogation of the mitotic checkpoint, and induces cancer cell death. These results suggest that TRAIL may increase the anticancer efficacy of microtubule-targeting drugs.
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania School of Medicine, Philadelphia Veterans Affairs Medical Center, Philadelphia, PA 19104, USA.
authors.forename: Mijin
authors.initials: M
authors.lastname: Kim
authors.forename: Jessica
authors.initials: J
authors.lastname: Liao
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Dowling
authors.forename: K Ranh
authors.initials: KR
authors.lastname: Voong
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Parker
authors.forename: Shulin
authors.initials: S
authors.lastname: Wang
authors.forename: Wafik S
authors.initials: WS
authors.lastname: El-Deiry
authors.forename: Gary D
authors.initials: GD
authors.lastname: Kao
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D004353:Drug Evaluation, Preclinical; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D045325:HCT116 Cells; D006801:Humans; D008870:Microtubules / Q000187:drug effects*; D008938:Mitosis / Q000187:drug effects* / Q000235:genetics; D008954:Models, Biological; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics; D015739:Nocodazole / Q000008:administration & dosage*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000008:administration & dosage* / Q000494:pharmacology*; D016896:Treatment Outcome; D014407:Tumor Cells, Cultured
chemical_list: D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases; D053148:Caspase 3; D015739:Nocodazole