Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID: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. 1114 26

Bcl-2 is up-regulated by EBV in immortalized lymphoblastoid B cells and is expressed in the majority of EBV-associated lymphoproliferative diseases, including posttransplant lymphoproliferative disorder (PTLD) and AIDS-related lymphoma (ARL). Given the antiapoptotic and chemoprotective effect of Bcl-2, it represents a logical target for modulation using antisense strategies in PTLD and ARL. We previously examined the antitumor effects of a fully phosphorothioated Bcl-2 antisense oligonucleotide, G3139, in EBV(+) lymphoproliferative disease in vitro and in vivo using the human/severe combined immunodeficient (SCID) chimeric model of PTLD. These studies showed that G3139 treatment decreased Bcl-2 protein levels in association with antiproliferative and proapoptotic effects in lymphoblastoid cell lines (LCLs) in vitro. In vivo, although G3139 treatment completely abrogated EBV(+) lymphoid tumor engraftment in the human/SCID model of PTLD, antisense treatment alone was not curative in animals with established tumors. Because the humanized anti-CD20 antibody, rituximab, has antitumor activity in patients with PTLD and stimulates apoptosis in some lymphoid cell lines, we sought to determine whether Bcl-2 antisense treatment potentiates the antitumor effects of rituximab in EBV-associated lymphoproliferative disease in vitro and in vivo. Proliferation assays by thymidine uptake in LCLs showed that G3139 but not control oligonucleotides augmented the antiproliferative effect of rituximab. Flow cytometric terminal deoxynucleotidyltransferase-mediated nick end labeling assays confirmed that G3139 treatment enhanced the apoptotic response of LCLs to rituximab, and this interaction was oligonucleotide sequence dependent. To test the in vivo efficacy of G3139 and rituximab in the human/SCID model of PTLD, we used a delayed treatment schedule that permitted detection of enhanced antitumor activity of combination therapy. Although G3139 or rituximab treatment significantly prolonged survival compared with untreated controls, 89% of animals in the monotherapy arms died with disseminated tumors. In contrast, 79% of animals in the combined G3139 and rituximab arm remained tumor free for the duration of follow-up (>160 days) with no evidence of tumors at the time of sacrifice, indicating that G3139 in combination with rituximab was curative therapy in the majority of tumor-bearing animals. These studies demonstrated that G3139 potentiates the antitumor response of PTLD to rituximab in vivo and augments the antiproliferative and apoptotic effects of rituximab in vitro in LCLs. This is the first report of G3139 potentiating the antitumor activity of an antibody-based therapy both in vitro and in vivo. Bcl-2 antisense oligonucleotide therapy in combination with rituximab may represent a promising nontoxic and effective targeted therapy for EBV-associated lymphoproliferative diseases such as PTLD and ARL. Furthermore, this approach may have broader applications to other Bcl-2- and CD20-expressing lymphoid malignancies.
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PMID:Bcl-2 antisense (G3139, Genasense) enhances the in vitro and in vivo response of Epstein-Barr virus-associated lymphoproliferative disease to rituximab. 1273 52