Antisense to the Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP-1) sensitizes EBV-immortalized B cells to transforming growth factor-beta and chemotherapeutic agents.
The Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP-1) is absolutely required for EBV transformation of B cells. LMP-1 mimics a constitutively activated receptor of the tumor necrosis factor receptor family, mediating diverse oncogenic functions that influence growth, differentiation and susceptibility to apoptosis. Given the critical functions of LMP-1 in EBV-associated transformation, it represents a rational therapeutic target for modulation. We used antisense oligodeoxynucleotides targeted to LMP-1 as a strategy to suppress LMP-1 expression and thereby inhibit its functions. In previous studies, we have shown that short-term treatment of EBV-positive lymphoblastoid cell lines (LCLs) with LMP-1 antisense oligodeoxynucleotides can dramatically reduce levels of LMP-1 protein in association with inhibition of proliferation, stimulation of apoptosis, down-regulation of Bcl-2 and Mcl-1 and enhanced sensitivity to the chemotherapeutic agent, etoposide. Here, we provide further evidence of the profound effects of reducing LMP-1 levels using antisense oligodeoxynucleotides in EBV-transformed B cells. We have shown that LMP-1 antisense treatment of LCLs partially restores sensitivity to the anti-proliferative and apoptotic effects of transforming growth factor-beta, a potent negative regulator of normal human B-cell growth, in association with a reduction in cyclin D2 levels. In addition, LMP-1 antisense sensitizes LCLs to chemotherapeutic drugs from diverse classes, including etoposide, vincristine and dexamethasone, by enhancing apoptotic cell death. Finally, the anti-proliferative and apoptotic effects of LMP-1 antisense treatment were observed not only in laboratory-derived LCLs, but also in an EBV-positive cell line derived from an AIDS-related lymphoma. These studies demonstrate that antisense targeting of LMP-1 represents a rational therapeutic strategy for EBV-positive lymphoproliferative disorders.
Kenney
J L
JL
Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520-8032, USA.
Guinness
M E
ME
Reiss
M
M
Lacy
J
J
D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001402:B-Lymphocytes / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002461:Cell Line, Transformed; D002469:Cell Separation; D056742:Cyclin D2; D016213:Cyclins / Q000378:metabolism; D016373:DNA, Antisense / Q000378:metabolism* / Q000627:therapeutic use; D003907:Dexamethasone / Q000494:pharmacology; D015536:Down-Regulation; D005047:Etoposide / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D008223:Lymphoma / Q000378:metabolism; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014750:Vincristine / Q000494:pharmacology; D014763:Viral Matrix Proteins / Q000235:genetics*
D018931:Antineoplastic Agents, Hormonal; D000972:Antineoplastic Agents, Phytogenic; C080336:CCND2 protein, human; D056742:Cyclin D2; D016213:Cyclins; D016373:DNA, Antisense; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016212:Transforming Growth Factor beta; D014763:Viral Matrix Proteins; D014750:Vincristine; D005047:Etoposide; D003907:Dexamethasone