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)

An EBV(-) BL (Burkitt lymphoma) line (Black93), established from a patient exhibiting glucocorticoid-induced ATLS (acute tumor lysis syndrome), was highly sensitive to dexamethazone (DX) in vitro in the studies including 18 lymphoid cell lines (10 BL lines). In the BL lines, the highly sensitive ones always lacked Bcl-2(bcl-2 protein), while the DX resistant ones expressed Bcl-2. Black93 is the first BL cell-line derived from a ATLS patient, proving that cell lines can be established in vitro from ATLS patients. Since some pre-B ALL lines expressing Bcl-2 were DX-sensitive, the relationship between Bcl-2 and DX-sensitivity is not straight-forward. In the BL cells, however, the absence of Bcl-2 appears to be responsible for the DX-sensitivity. The DX-sensitivity and the absence of Bcl-2 is a major characteristic carried by t(8;14) neoplasms. In addition, there may be a stage of B-lineage differentiation without Bcl-2. While rare BL cases have been reported to express TdT (terminal desoxynucleotidyl transferase), Tree92 is the first such line, expressing S-Ig(mu, lambda), TdT and RAG (recombination activating gene)-1. When surface mu is ligated with antibody, RAG-1 was suppressed in expression, indicating that the signal through S-Ig can modulate the expression of RAG-1 in the Tree92 cells. Chromosome translocation is known to be associated with a specific stage of differentiation. Such specific stage for t(8;14), however, is broad enough to cover S-Ig(+), TdT(+) and RAG-1(+) stage, too. The phenotypic classification of leukemia/lymphoma and the delineation of differentiation scheme of normal hematopoietic cells, are dependent on each other. The documentation of the properties such as DX-sensitivity, the absence of Bcl-2, the expression of RAG-1 and its modulation by the signal through S-Ig is an example in which the diverse properties of human t(8;14) neoplasms can contribute for delineating the differentiation scheme of normal hematopoietic cells more precisely.
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PMID:Diverse properties of human t(8;14) neoplasms: [1] ATLS and absence of BCL-2 [2] modulation of RAG-1 expression with S-Ig ligation. 918 67

Bcl-2 protein is upregulated in a wide variety of lymphoid malignancies, including chronic lymphocytic leukemia (CLL). The protein is thought to be responsible for maintaining the viability of malignant lymphoid cells and may contribute to chemotherapy and radiotherapy resistance. Previous studies have shown that reduction of bcl-2 expression by antisense therapy sensitizes cells to chemotherapy-induced apoptosis. In vitro, the Bcl-2 antisense drug oblimersen sodium (Genasense, previously known as G3139) enhances the apoptotic response in CLL cells to fludarabine (Fludara), corticosteroids, alemtuzumab (Campath), and rituximab (Rituxan). A phase I trial in patients with refractory/relapsed CLL showed that patients with CLL were more sensitive to oblimersen than patients with solid tumors. The maximum tolerated oblimersen dose was 3 mg/kg/d, and the most common dose-limiting reaction was hypotension, frequently in association with high spiking fever. In this study, oblimersen displayed limited single-agent activity, including tumor lysis syndrome, transient decreases in circulating CLL cells, and reduction of splenomegaly and size of lymph nodes. Major responses were observed in 9% of patients. Subsequently, a phase III trial evaluating fludarabine and cyclophosphamide with or without oblimersen (3 mg/kg/d for 7 days) was initiated in patients with relapsed or refractory CLL. This trial recently completed accrual of 241 patients.
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PMID:Potential therapeutic applications of oblimersen in CLL. 1565 Nov 75

Among adults in Western countries, chronic lymphocytic leukemia (CLL) is the most prevalent form of leukemia. CLL primarily affects the elderly and may be associated with multiple comorbidities. A cure has not been identified, and new treatment options are needed. Expression of Bcl-2 protein is associated with the pathogenesis of CLL and chemotherapy resistance. Oblimersen, a Bcl-2 antisense phosphorothioate oligonucleotide, is being evaluated in patients with CLL and other cancers; trials through Phase III have been completed. In the setting of relapsed/refractory CLL, single-agent oblimersen demonstrates modest activity, whereas the addition of oblimersen to fludarabine/cyclophosphamide significantly improves the rate of complete and nodular partial responses; moreover, these responses are durable and associated with clinical benefit. Oblimersen is more efficacious in relapsed rather than refractory patients. The side effect profile of oblimersen, alone or in combination with standard chemotherapy, is favorable compared with currently available chemotherapies. In the first cycle, an infusion reaction with or without tumor lysis syndrome is uncommon, and transient thrombocytopenia is observed. Catheter-related complications are associated with the need for continuous intravenous infusion of oblimersen over several days; other routes of administration are under clinical investigation. Oblimersen is a promising therapeutic approach for patients with relapsed CLL and should be further evaluated in the front-line setting.
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PMID:Oblimersen for the treatment of patients with chronic lymphocytic leukemia. 1847 9

Alkylating agents and purine analogues have been the mainstays of therapy for chronic lymphocytic leukemia (CLL) for decades. The past decade witnessed the general clinical use of monoclonal antibodies such as rituximab and alemtuzumab, both as single agents and in combination regimens with cytotoxic drugs, for previously untreated and relapsed CLL. First-line chemoimmunotherapy regimens combining rituximab and purine analogues have greatly improved initial response rates and progression-free survival. Despite these advances in first-line therapy, patients with CLL invariably experience relapse and often acquire high-risk chromosomal abnormalities, such as del(11q22) and del(17p13), which result in resistance to current therapies. Patients who are refractory to fludarabine-based therapy have a median survival of <1 year. Therefore, new agents with novel mechanisms of action are needed for the treatment of patients with relapsed CLL, particularly for patients with high-risk genetic features. Recent clinical studies have examined the tolerability and efficacy of several novel agents in relapsed CLL: (1) the alkylator bendamustine, (2) the cyclin-dependent kinase inhibitor flavopiridol, (3) the immunomodulating drug lenalidomide, (4) the bcl-2 antisense oligonucleotide oblimersen, and (5) the Bcl-2 small-molecule inhibitor obatoclax. While these agents have demonstrated exciting clinical activity against genetically high-risk CLL, they have also induced toxicities that have not been commonly observed with previous CLL therapies. The most notable toxicities have been tumor lysis syndrome and tumor flare, which are potentially serious or even fatal complications of these new therapies. Thus, further studies are needed to define these agents' biologic mechanism(s) of action, clinical activity, and safety.
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PMID:Novel agents in chronic lymphocytic leukemia: efficacy and tolerability of new therapies. 1895 44

Management of chronic lymphocytic leukemia has changed markedly over the last several years with the emergence of several novel oral agents targeting B-cell receptor and Bcl-2 signaling pathways. For patients requiring treatment, ibrutinib, idelalisib, and venetoclax offer unique clinical benefits with a different set of therapeutic considerations compared with traditional parenteral therapy. Despite the conveniences afforded by oral therapy, these agents also carry unique logistical obstacles. Drug interactions with agents that are metabolized via the cytochrome P450 3A4 pathway are possible with all three agents. Unique treatment-related adverse events including bleeding and atrial fibrillation with ibrutinib, hepatotoxicity with idelalisib, and tumor lysis syndrome with venetoclax can be severe and dose limiting. Furthermore, dose adjustments for organ dysfunction may also be warranted. Here, we review the available literature on the pharmacokinetic and pharmacodynamic properties of these novel agents to guide the reader in the appropriate use of ibrutinib, idelalisib, and venetoclax.
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PMID:Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Chronic Lymphocytic Leukemia: Ibrutinib, Idelalisib, and Venetoclax. 2834 93

Targeted therapies including the engineered afucosylated anti-CD20 monoclonal antibody obinutuzumab, Bruton's tyrosine kinase inhibitor ibrutinib, and B-cell lymphoma protein 2 inhibitor venetoclax have demonstrated significant clinical activity in chronic lymphocytic leukemia (CLL) and, based on their complementary mechanisms, are ideal for combination. However, combining venetoclax with other active agents raises safety concerns, as it may increase the risk for tumor lysis syndrome. To minimize this risk, we designed and implemented a fixed-duration regimen using sequentially administered obinutuzumab followed by ibrutinib (cycle 2) and venetoclax (cycle 3), for a total of fourteen 28-day cycles. This phase 1b study included 12 patients with relapsed or refractory CLL. We tested 3 dose levels of venetoclax and identified the doses of all 3 agents approved by the US Food and Drug Administration for use in the combination. Adverse events were consistent with known toxicities of the individual agents, with hematologic adverse events being most frequent. No clinically significant tumor lysis syndrome occurred. The overall response rate was 92% (95% confidence interval, 62%-100%), with 42% (5/12) achieving a complete remission or complete remission with incomplete marrow recovery. There were 6 patients with no detectable CLL in both the blood and bone marrow at the end of treatment. We found this regimen to be safe and tolerable in CLL, and capable of inducing deep responses, justifying future study in our ongoing phase 2 cohorts of relapsed or refractory and treatment-naive patients, as well as larger phase 3 trials currently in planning. This trial was registered at www.clinicaltrials.gov as #NCT02427451.
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PMID:Phase 1b study of obinutuzumab, ibrutinib, and venetoclax in relapsed and refractory chronic lymphocytic leukemia. 3030 74