Interactive effects of HDAC inhibitors and TRAIL on apoptosis are associated with changes in mitochondrial functions and expressions of cell cycle regulatory genes in multiple myeloma

Neoplasia. 2005 Jul;7(7):646-57. doi: 10.1593/neo.04655.

Abstract

In this study, we have evaluated the cytotoxic effect of combining two HDAC inhibitors, SAHA and TSA, with TRAIL in human multiple myeloma cell lines. Low doses of SAHA or TSA enhanced the cytotoxic and apoptotic effects of TRAIL and upregulated the surface expression of TRAIL death receptors (DR4 and/or DR5). SAHA and TSA induced G1 phase cell cycle growth arrest by upregulating p21(WAF1) and p27(Kip1) expression and by inhibiting E2F transcriptional activity. The enhanced TRAIL effect after pretreatment with HDAC inhibitors was consistent with the upregulation of the proapoptotic Bcl-2 family members (Bim, Bak, Bax, Noxa, and PUMA), the downregulation of the anti-apoptotic members of the Bcl-2 family (Bcl-2 and Bcl-X(L)), and IAPs. SAHA and TSA dissipated the mitochondrial membrane potential and enhanced the release of Omi/HtrA2 and AIF from the mitochondria to the cytosol. The cytotoxic effect of both SAHA and TSA was caspase- and calpain-independent. Inhibition of NF(kappa)B activation by the proteasome inhibitor, MG132, enhanced the apoptotic effect of TSA. Our study demonstrated the enhancing effects of HDAC inhibitors on apoptosis when combined with TRAIL and, for the first time, emphasized the role of AIF in mediating the cytotoxic effects of HDAC inhibitors.

MeSH terms

  • Amino Acid Chloromethyl Ketones / pharmacology
  • Annexin A5 / pharmacology
  • Apoptosis Regulatory Proteins
  • Apoptosis*
  • Calpain / metabolism
  • Caspases / metabolism
  • Cell Cycle / drug effects
  • Cell Cycle Proteins / metabolism
  • Cell Line, Tumor
  • Cell Proliferation
  • Cyclin-Dependent Kinase Inhibitor p27
  • DNA-Binding Proteins / metabolism
  • Dose-Response Relationship, Drug
  • Down-Regulation
  • E2F Transcription Factors
  • Enzyme Inhibitors / pharmacology*
  • Flow Cytometry
  • G1 Phase
  • Gene Expression Regulation, Neoplastic*
  • Histone Deacetylase Inhibitors*
  • Histones / metabolism
  • Humans
  • Immunoblotting
  • Inhibitory Concentration 50
  • Leupeptins / pharmacology
  • Luciferases / metabolism
  • Membrane Glycoproteins / metabolism*
  • Membrane Potentials
  • Microscopy, Fluorescence
  • Mitochondria / metabolism*
  • Mitochondria / pathology
  • Multiple Myeloma / metabolism*
  • Multiple Myeloma / pathology*
  • NF-kappa B / metabolism
  • Phosphorylation
  • Propidium / pharmacology
  • Protein Binding
  • Ribonucleases / metabolism
  • Subcellular Fractions / metabolism
  • TNF-Related Apoptosis-Inducing Ligand
  • Time Factors
  • Transcription Factors / metabolism
  • Tumor Necrosis Factor-alpha / metabolism*
  • Tumor Suppressor Proteins / metabolism
  • Up-Regulation

Substances

  • Amino Acid Chloromethyl Ketones
  • Annexin A5
  • Apoptosis Regulatory Proteins
  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • E2F Transcription Factors
  • Enzyme Inhibitors
  • Histone Deacetylase Inhibitors
  • Histones
  • Leupeptins
  • Membrane Glycoproteins
  • NF-kappa B
  • TNF-Related Apoptosis-Inducing Ligand
  • TNFSF10 protein, human
  • Transcription Factors
  • Tumor Necrosis Factor-alpha
  • Tumor Suppressor Proteins
  • benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone
  • Cyclin-Dependent Kinase Inhibitor p27
  • Propidium
  • Luciferases
  • Ribonucleases
  • Calpain
  • Caspases
  • benzyloxycarbonylleucyl-leucyl-leucine aldehyde