title: Chemosensitization of myeloma plasma cells by an antisense-mediated downregulation of Bcl-2 protein.
abstract: An antisense oligodeoxynucleotide (ODN) complementary to the first six codons of the Bcl-2 mRNA, G3139 (oblimersen sodium; Genasense), has been shown to downregulate Bcl-2 and produce responses in a variety of malignancies including drug-resistant lymphoma. Incubation of ex vivo purified plasma cells from patients with multiple myeloma (MM) with carboxyfluorescein (FAM)-labeled antisense ODNs resulted in a time- and dose-dependent uptake in the cytoplasm and nucleus. No major differences in uptake of Bcl-2 antisense ODNs were observed among patients' samples. Incubation of purified myeloma plasma cells with G3139, but not solvent or reverse polarity control ODNs, resulted in a reduction (>75%) of Bcl-2 mRNA levels after 2 and 4 days, as measured by Real-Time PCR. Treatment with G3139 led to a sequence-specific reduction of Bcl-2 protein levels within 4 days of exposure in 10 out of 11 clinical samples from patients with chemosensitive and multidrug-resistant disease, without significant reduction of alpha-Actin, Bax, Bcl-XL, or Mcl-1 proteins. This resulted in a significantly enhanced sensitivity of the myeloma tumor cells to dexamethasone or doxorubicin-induced apoptosis. G3139 can consistently enter myeloma cells, downregulate the expression of Bcl-2, and enhance the efficacy of myeloma therapy. These data support further clinical evaluation of G3139 therapy in multiple myeloma.
authors.affiliation: Department of Immunology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: N W C J
authors.initials: NW
authors.lastname: van de Donk
authors.forename: M M J
authors.initials: MM
authors.lastname: Kamphuis
authors.forename: M
authors.initials: M
authors.lastname: van Dijk
authors.forename: H P E
authors.initials: HP
authors.lastname: Borst
authors.forename: A C
authors.initials: AC
authors.lastname: Bloem
authors.forename: H M
authors.initials: HM
authors.lastname: Lokhorst
mesh_terms: D000368:Aged; D017304:Annexin A5 / Q000378:metabolism; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D001853:Bone Marrow / Q000473:pathology; D003907:Dexamethasone / Q000009:adverse effects / Q000627:therapeutic use; D004317:Doxorubicin / Q000009:adverse effects / Q000627:therapeutic use; D019008:Drug Resistance, Neoplasm; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000627:therapeutic use* / Q000633:toxicity; D010950:Plasma Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013873:Thionucleotides / Q000627:therapeutic use*; D014750:Vincristine / Q000009:adverse effects; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
chemical_list: D017304:Annexin A5; D000970:Antineoplastic Agents; D018931:Antineoplastic Agents, Hormonal; C494826:BAX protein, human; C494811:BCL2L1 protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D016376:Oligonucleotides, Antisense; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D013873:Thionucleotides; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D014750:Vincristine; D003907:Dexamethasone; D004317:Doxorubicin; C408162:oblimersen