Induction of cell cycle arrest and apoptosis by the proteasome inhibitor PS-341 in Hodgkin disease cell lines is independent of inhibitor of nuclear factor-kappaB mutations or activation of the CD30, CD40, and RANK receptors.
OBJECTIVE
The malignant Hodgkin and Reed-Sternberg cells of Hodgkin disease (HD) are known to constitutively express high levels of activated nuclear factor kappaB (NF-kappaB), which plays an important role in their survival. The proteasome inhibitor PS-341 has been recently shown to modulate tumor cell proliferation and survival by inhibiting NF-kappaB and modulating critical cellular regulatory proteins, but its activity in cells carrying IkappaBalpha gene mutations has not been reported previously.


METHODS
The activity of PS-341 in four well-characterized, HD-derived cell lines. Cell proliferation and apoptosis were determined by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy-phenyl)-2-(4-sulfonyl)-2H-tetrazolium (MTS) and Annexin-V binding methods, respectively. Cell cycle analysis was determined by flow cytometry. Intracellular protein levels were determined by Western blot.


RESULTS
PS-341 demonstrated a strong antiproliferative activity, which was irrespective of the status of mutations in IkappaBalpha and even the presence of CD30, CD40, or RANK receptor activation. This effect was attributable to the induction of apoptosis and cell cycle arrest at the G(2)-M phase. PS-341 not only inhibited nuclear localization of NF-kappaB but also activated the caspase cascade, increased p21 and Bax levels, and decreased Bcl-2 levels. Furthermore, PS-341 enhanced the effect of gemcitabine chemotherapy and potentiated the effect of tumor necrosis factor-related apoptosis-inducing ligand/APO2L and two agonistic antibodies to tumor necrosis factor-related apoptosis-inducing ligand death receptors R1 and R2.


CONCLUSIONS
The in vitro activity of PS-341 against HD-derived cell lines suggests that PS-341 may have a therapeutic value for the treatment of HD.
Zheng
Bei
B
Departments of Lymphoma/Myeloma, Bioimmunotherapy, and Cancer Biology, M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
Georgakis
Georgios V
GV
Li
Yang
Y
Bharti
Alok
A
McConkey
David
D
Aggarwal
Bharat B
BB
Younes
Anas
A
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D001897:Boronic Acids / Q000494:pharmacology*; D000069286:Bortezomib; D019013:CD40 Antigens / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003546:Cysteine Endopeptidases; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D006689:Hodgkin Disease / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans; D020672:I-kappa B Proteins / Q000235:genetics; D017730:Ki-1 Antigen / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism / Q000494:pharmacology; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors; D009154:Mutation; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex; D011719:Pyrazines / Q000494:pharmacology*; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000276:immunology; D053221:TNF-Related Apoptosis-Inducing Ligand; D013997:Time Factors; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D051017:Apoptosis Regulatory Proteins; D001897:Boronic Acids; D019013:CD40 Antigens; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D020672:I-kappa B Proteins; D017730:Ki-1 Antigen; D008562:Membrane Glycoproteins; D009097:Multienzyme Complexes; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D011480:Protease Inhibitors; D011719:Pyrazines; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505639:TNFRSF10B protein, human; C505686:TNFRSF11A protein, human; C505653:TNFSF10 protein, human; C505688:TNFSF11 protein, human; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D000072000:NF-KappaB Inhibitor alpha; D000069286:Bortezomib; D020169:Caspases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex