title: Roscovitine sensitizes glioma cells to TRAIL-mediated apoptosis by downregulation of survivin and XIAP.
abstract: The cytotoxic effect of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is limited in many glioma cell lines. However, treatment with TRAIL in combination with subtoxic doses of roscovitine, a specific inhibitor of Cdc2 and Cdk2, induced rapid apoptosis in TRAIL-resistant glioma cells. Roscovitine could sensitize Bcl-2- or Bcl-xL-overexpressing glioma cells, but not human astrocytes, to TRAIL-induced apoptosis, offering an attractive strategy for safely treating resistant gliomas. Treatment with roscovitine significantly inhibited Cdc2 activity, and expression of a dominant-negative Cdc2 mutant sensitized glioma cells to TRAIL-induced apoptosis. While the proteolytic processing of procaspase-3 by TRAIL was partially blocked in U87MG and T98 glioma cells, treatment with roscovitine recovered TRAIL-induced activation of caspases very efficiently in these cells. We found that treatment with roscovitine or expression of a dominant-negative Cdc2 mutant downregulated the protein levels of survivin and XIAP, two major caspase inhibitors. Overexpression of survivin or XIAP attenuated the apoptosis induced by roscovitine and TRAIL. Taken together, these results suggest that downregulation of survivin and XIAP by subtoxic doses of roscovitine contributes to the amplification of caspase cascades, thereby overcoming glioma cell resistance to TRAIL-mediated apoptosis.
authors.affiliation: Institute for Medical Sciences, Ajou University School of Medicine, Suwon, South Korea.
authors.forename: Eun Hee
authors.initials: EH
authors.lastname: Kim
authors.forename: Seung U
authors.initials: SU
authors.lastname: Kim
authors.forename: Deug Y
authors.initials: DY
authors.lastname: Shin
authors.forename: Kyeong Sook
authors.initials: KS
authors.lastname: Choi
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism; D016203:CDC2 Protein Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects*; D005910:Glioma / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009363:Neoplasm Proteins; D011506:Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011687:Purines / Q000494:pharmacology*; D000077546:Roscovitine; D000077022:Survivin; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D051636:X-Linked Inhibitor of Apoptosis Protein; D051020:bcl-X Protein
chemical_list: D051017:Apoptosis Regulatory Proteins; C494811:BCL2L1 protein, human; C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D008562:Membrane Glycoproteins; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011687:Purines; D000077022:Survivin; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; D051020:bcl-X Protein; D000077546:Roscovitine; D016203:CDC2 Protein Kinase