Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although myeloma shows responsiveness in intensive chemotherapy, overall survival remains less than 40% at 2 years. Since myeloma appears to be dependent on cytokines, such as IL-6, we hypothesized that targeting signal transduction molecules could effectively treat myeloma. Two myeloma cell lines U266 and RPMI-8226 and CD38+ myeloma cells were studied by immune complex kinase assay or anti-phosphotyrosine blot for evidence of constitutive activation of tyrosine kinases. Growth arrest and apoptosis were evaluated in these two cell lines following their treatment with specific kinase inhibitors. We found that a variety of Src and Janus kinases were present and constitutively active in U266 and RPMI-8226 cells. Inhibitors of both Src and Janus kinases were inferior to the cyclin-dependent kinase inhibitor, flavopiridol, in inducing both growth arrest with GI50 of 100 nM and apoptosis in both cell lines and CD38+ myeloma cells. Although, flavopiridol did not affect cyclin D1 and cyclin A levels, it inhibited Mcl-1 and Bcl-2 protein levels and cyclin-dependent kinase 2 activity. Flavopiridol is a well-tolerated drug, currently in phase I-II trials for a variety of tumors. A clinical trial using flavopiridol should be performed in patients with myeloma. Its mechanism of action may involve targets other than the cyclin-dependent kinases.
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PMID:Growth inhibition and apoptosis of myeloma cells by the CDK inhibitor flavopiridol. 1179 16

Interactions between the cyclin-dependent kinase inhibitor flavopiridol and the small-molecule Bcl-2 antagonist HA14-1 were examined in human multiple myeloma cells. Whereas individual treatment of U266 myeloma cells with 10 micromol/L HA14-1 or 100 nmol/L flavopiridol had little effect, exposure of cells to flavopiridol (6 hours) followed by HA14-1 (18 hours) resulted in a striking increase in mitochondrial dysfunction (cytochrome c and Smac/DIABLO release; loss of mitochondrial membrane potential), activation of the caspase cascade, apoptosis, and diminished clonogenic survival. Similar findings were noted in other myeloma cell lines (e.g., MM.1S, RPMI8226, and NCI-H929) as well as in those resistant to dexamethasone and cytotoxic agents (e.g., MM.1R, 8226/Dox40, and 8226/LR5). Combined exposure to flavopiridol and HA14-1 was associated with down-regulation of Mcl-1 and Bcl-xL, Bid cleavage, and mitochondrial translocation of Bax. Flavopiridol/HA14-1-treated cells also exhibited a pronounced activation of Jun NH2-terminal kinase, a modest activation of p38 mitogen-activated protein kinase, and down-regulation of cyclin D1. Flavopiridol/HA14-1-induced apoptosis was associated with a marked increase in reactive oxygen species generation; moreover,both events were attenuated by the antioxidant N-acetyl-l-cysteine. Finally, in contrast to dexamethasone, flavopiridol/HA14-1-induced lethality was unaffected by exogenous interleukin-6 or insulin-like growth factor-I. Together, these findings indicate that flavopiridol and the small-molecule Bcl-2 antagonist HA14-1 cooperate to trigger oxidant injury, mitochondrial dysfunction, caspase activation, and apoptosis in human multiple myeloma cells and suggest that this approach may warrant further evaluation as an antimyeloma strategy.
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PMID:The small-molecule Bcl-2 inhibitor HA14-1 interacts synergistically with flavopiridol to induce mitochondrial injury and apoptosis in human myeloma cells through a free radical-dependent and Jun NH2-terminal kinase-dependent mechanism. 1563 44

Flavopiridol downregulates anti-apoptotic regulators including Mcl-1, upregulates p53, globally attenuates transcription through inhibition of P-TEFb, binds to DNA, and inhibits angiogenesis. Eighteen myeloma patients were treated with 1-hour flavopiridol infusions for 3 consecutive days every 21 days. Immunoblotting for Mcl-1, Bcl-2, p53, cyclin D, phosphoRNA polymerase II and phosphoSTAT 3 was conducted on myeloma cells. Ex vivo flavopiridol treatment of cells resulted in cytotoxicity, but only after longer exposure times at higher flavopiridol concentrations than were anticipated to be achieved in vivo. No anti-myeloma activity was observed in vivo. As administered, flavopiridol has disappointing activity as a single agent in advanced myeloma.
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PMID:Flavopiridol in patients with relapsed or refractory multiple myeloma: a phase 2 trial with clinical and pharmacodynamic end-points. 1650 51

Hoechst is developing flavopiridol, a synthetic flavonoid based on an extract from an Indian plant, for the potential treatment of cancer. Flavopiridol, a cyclin-dependent kinase inhibitor, arrests cell division and causes apoptosis in non-small lung cancer cells [283660]. A phase II trial, in collaboration with the National Cancer Institute, has commenced at the University of Chicago Medical Center, which involves patients with high or intermediate-grade lymphoma or multiple myeloma [272937], [277372]. In ex vivo experiments with tumor cells from refractory chronic lymphoblastic leukemia, dose-dependent CDK2 inhibition associated with apoptotic changes was seen at concentrations greater than 100 nM of flavopiridol. In vitro pharmacokinetic studies have shown that flavopiridol undergoes hepatic biotransformation to its corresponding glucoronide by uridine diphosphate glucoronosyltransferases [283791]. Flavopiridol inhibits CDK with an IC50 value of 0.4 mM [285707]. Preclinical toxicology studies in rats and dogs demonstrated dose-related leukopenia and drug-related lesions in the thymus, spleen and bone marrow. The gastrointestinal and bone marrow toxicity was dose-limiting [178579]. Hoechst Marion Roussel expects to launch flavopiridol in the year 2001, with potential sales in excess of DM 750 million [288651].
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PMID:Flavopiridol Hoechst AG. 1846 38

Patients with chronic lymphocytic leukemia (CLL) with high-risk cytogenetic features such as del(17p13) have limited treatment options and decreased overall survival. Dysfunction of p53 leads to resistance to fludarabine-based therapies. Cyclin-dependent kinase inhibitors (CDKi) are a novel class of agents that induce apoptosis in CLL cells independent of p53 mutational status. The synthetic flavone flavopiridol demonstrated promising in vitro activity in CLL. In initial phase I studies using a continuous infusion dosing schedule in a variety of malignancies, no clinical activity was observed. Detailed pharmacokinetic modeling led to the development of a novel dosing schedule designed to achieve target drug concentrations in vivo. In phase I testing, this dosing schedule resulted in acute tumor lysis syndrome (TLS) as the dose-limiting toxicity. With the implementation of a standardized protocol to prevent severe TLS, flavopiridol was administered safely, and responses were observed in heavily pretreated, fludarabine-refractory patients, cytogenetically high-risk patients, and patients with bulky lymphadenopathy. In a pharmacokinetic analysis, flavopiridol area under the plasma concentration-time curve (AUC) correlated with clinical response and cytokine release syndrome. Phase II studies are under way with encouraging preliminary results. Flavopiridol is currently under active investigation in combination with other agents and as a means to eradicate minimal residual disease in patients following cytoreductive chemotherapy. Several other investigational CDKi in preclinical and early clinical development are briefly discussed in this review.
Clin Lymphoma Myeloma 2009
PMID:Flavopiridol in chronic lymphocytic leukemia: a concise review. 1977 38

Chromone alkaloids and flavoalkaloids are an important group of natural products possessing promising medicinal properties. A chromone alkaloid rohitukine is a major bioactive chemical constituent of plant Dysoxylum binectariferum (Meliaceae) Hook. which is phylogenetically related to the Ayurvedic plant, D. malabaricum Bedd. used for treatment of rheumatoid arthritis. This chromone alkaloid led to discovery of two synthetic flavoalkaloids: flavopiridol (Sanofi) and P-276-00 (Piramal) which have reached to advanced stages of clinical development for cancer treatment. Flavopiridol (Alvocidib; L868275; HMR-1275; NSC 649890 of Sanofi-Aventis + NCI) is approved as an orphan drug for treatment of chronic lymphocytic leukemia and is currently undergoing phase II studies as monotherapy and also as in combination regimes with traditional chemotherapy agents. P-276-00 (12) is currently in phase II clinical studies for advanced refractory neoplasms and multiple myeloma. Extensive amount of medicinal chemistry efforts have been reported on these flavoalkaloids. Flavopiridol demonstrated potent and specific in vitro inhibition of variety of cyclindependent kinases with clear block in cell cycle progression at the G1/S and G2/M phases. Preclinical studies demonstrated the capacity of flavopiridol to induce programmed cell death, promote differentiation, inhibit angiogenic processes and modulate transcriptional events. The co-crystallised structure of deschloro-flavopiridol with CDK-2 is available and key interactions in the ATP binding site have been reported. Flavopiridol has also been studied for the treatment of arthritis and atherosclerotic plaque formation. The present review comprises discovery, medicinal chemistry, pharmacology and preclinical/clinical development of flavoalkaloids as CDK inhibitors.
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PMID:Cyclin-dependent kinase inhibition by flavoalkaloids. 2251 51