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ABSTRACT: Multi-drug resistance and cumulative cardiotoxicity are major limitations for the clinical use of anthracyclines. Here, we evaluated and compared the cross-resistance of amrubicin, a third-generation synthetic anthracycline and potent topoisomerase (topo)-II inhibitor with little or no observed cardiotoxicity to other anthracyclines and the topo-II inhibitor etoposide in drug-resistant tumor models in order to elucidate its potential mechanisms of action.
Amrubicin activity was assessed in multi-drug-resistant cell lines and human tumor explants using cytotoxicity assays, confocal microscopy, fluorescence time-lapse imaging, flow cytometry, immunoblotting, and gene expression profiling techniques.
We demonstrate that both doxorubicin-resistant tumor cell lines and several drug-resistant human ovarian and breast tumor explants retain sensitivity to amrubicin. In addition, we observed similar levels of amrubicin uptake and accumulation in doxorubicin-sensitive versus doxorubicin-resistant cell lines. Although amrubicin is a weak P-glycoprotein substrate, transport and retention of amrubicin were not solely modulated by P-glycoprotein in the resistant cell lines overexpressing drug efflux pumps. The cellular retention of amrubicin is likely to be a result of rapid influx due to its high intrinsic permeability and lipophilic properties, and this may explain why amrubicin overcomes pleiotropic drug resistance. Consistent with drug accumulation studies, amrubicin induced DNA damage, G(2)-M cell cycle arrest, and apoptosis in both doxorubicin-sensitive and doxorubicin-resistant lines. Using gene expression profiling studies, several classes of genes were significantly and uniquely regulated following amrubicin, but not doxorubicin or etoposide, treatment.
Amrubicin appears to have a distinct mode of action that overcomes typical anthracycline resistance mechanisms. Therefore, amrubicin may be useful in the treatment of anthracycline-refractory or anthracycline-resistant tumors.
Cancer Chemotherapy and Pharmacology 11/2011; 69(4):965-76. · 2.83 Impact Factor
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ABSTRACT: Histone deacetylase inhibitors are a group of recently developed compounds that modulate cell growth and survival. We evaluated the effects of the histone deacetylase inhibitor MGCD0103 on growth of pancreatic carcinoma models following single agent treatment and in combination with gemcitabine. MGCD0103 inhibited tumor cell growth and acted synergistically with gemcitabine to enhance its cytotoxic effects. Gene expression analysis identified the cell cycle pathway as one of the most highly modulated gene groups. Our data suggest that MGCD0103 + gemcitabine might be an effective treatment for gemcitabine-refractory pancreatic cancer.
Cancer Science 03/2011; 102(6):1201-7. · 3.33 Impact Factor
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ABSTRACT: Lenalidomide has demonstrated clinical activity in myelodysplastic syndromes, particularly in patients with a deletion in the long arm of chromosome 5 (del[5q] abnormality). It has a direct effect on the del(5q) clone, which may contribute to its ability to induce cytogenetic responses. Lenalidomide also stimulates erythropoiesis, leading to erythroid responses in certain patients. Other effects include immunomodulation, anti-inflammatory effects and angiogenesis inhibition. New findings indicate that lenalidomide modulates key genes located within the del(5q) region, including tumor suppressor genes, and regulators of the actin cytoskeleton and cell membrane. Its effects on cytoskeleton regulation may explain its direct antitumor and immunomodulatory effects. This article provides an overview of the known effects of lenalidomide and new insights into its activity in del(5q) myelodysplastic syndromes.
Expert Review of Anti-infective Therapy 10/2010; 10(10):1663-72. · 2.65 Impact Factor
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ABSTRACT: Inhibition of histone deacetylase 6 (HDAC6)-dependent aggresome function by pan HDAC inhibitors was recently reported to be a key mechanism underlying the synergistic activity between proteasome inhibitors and HDAC inhibitors in a variety of tumour types. Because these combinations induce significant thrombocytopenia in vivo, we examined whether less toxic, isotype-selective HDAC inhibitors may still synergize with proteasome inhibitors, and if so, by what mechanisms. Here, we showed that the class I HDAC inhibitor, MGCD0103, has a potent antiproliferative activity in Hodgkin lymphoma (HL) cell lines. Furthermore, MGCD0103 induced tumour necrosis factor α (TNF-α) expression and secretion, which was associated with nuclear factor (NF)-κB activation. Selective inhibition of TNF-α expression by short interfering mRNA, or inhibition of MGCD0103-induced NF-kB activation by proteasome inhibitors enhanced MGCD0103-induced cell death. Thus, our results demonstrate that MGCD0103 may synergize with proteasome inhibitors by HDAC6-independent mechanisms, providing mechanistic rationale for exploring this potentially less toxic combination for the treatment of lymphoma.
British Journal of Haematology 09/2010; 151(4):387-96. · 4.94 Impact Factor
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ABSTRACT: The cytidine nucleoside analogs azacitidine (AZA) and decitabine (DAC) are used for the treatment of patients with myelodysplastic syndromes and acute myeloid leukemia (AML). Few non-clinical studies have directly compared the mechanisms of action of these agents in a head-to-head fashion, and the agents are often viewed as mechanistically similar DNA hypomethylating agents. To better understand the similarities and differences in mechanisms of these drugs, we compared their in vitro effects on several end points in human AML cell lines.
Both drugs effected DNA methyltransferase 1 depletion, DNA hypomethylation, and DNA damage induction, with DAC showing equivalent activity at concentrations 2- to 10-fold lower than AZA. At concentrations above 1 microM, AZA had a greater effect than DAC on reducing cell viability. Both drugs increased the sub-G1 fraction and apoptosis markers, with AZA decreasing all cell cycle phases and DAC causing an increase in G2-M. Total protein synthesis was reduced only by AZA, and drug-modulated gene expression profiles were largely non-overlapping.
These data demonstrate shared mechanisms of action of AZA and DAC on DNA-mediated markers of activity, but distinctly different effects in their actions on cell viability, protein synthesis, cell cycle, and gene expression. The differential effects of AZA may be mediated by RNA incorporation, as the distribution of AZA in nucleic acid of KG-1a cells was 65:35, RNA:DNA.
PLoS ONE 01/2010; 5(2):e9001. · 4.09 Impact Factor
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Debashis Sarker,
Rhoda Molife,
T R Jeffrey Evans,
Maryon Hardie,
Cheryl Marriott,
Priska Butzberger-Zimmerli,
Rosemary Morrison,
Judith A Fox, Carla Heise,
Sharianne Louie,
Natasha Aziz,
Felix Garzon,
Glenn Michelson,
Ian R Judson,
Dalal Jadayel,
Edgar Braendle,
Johann S de Bono
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ABSTRACT: To determine the maximum tolerated dose (MTD) dose-limiting toxicity, and pharmacokinetic and pharmacodynamic profile of TKI258 (formerly CHIR-258).
A phase I dose escalating trial in patients with advanced solid tumors was performed. Treatment was initially as single daily doses on an intermittent 7-day on/7-day off schedule. Following a protocol amendment, a second schedule comprised, during cycle 1, 7-day on/7-day off treatment followed by 14 days of continuous daily dosing; subsequent cycles comprised 28 days of daily dosing. Pharmacokinetics and evaluation of phosphorylated extracellular signal-regulated kinase (ERK) in peripheral blood mononuclear cells were done during the first 28 days of each schedule.
Thirty-five patients were treated in four intermittent (25-100 mg/d) and three continuous (100-175 mg/d) dosing cohorts. Observed drug-related toxicities were nausea and vomiting, fatigue, headache, anorexia, and diarrhea. Dose-limiting toxicities were grade 3 hypertension in one patient at 100 mg continuous dosing, grade 3 anorexia in a second patient at 175 mg, and grade 3 alkaline phosphatase elevation in a third patient at 175 mg. One patient had a partial response (melanoma) and two patients had stable disease >6 months. TKI258 pharmacokinetics were linear over the dose range of 25 to 175 mg. Five of 14 evaluable patients had modulation of phosphorylated ERK levels.
The MTD was defined as 125 mg/d. Evidence of antitumor activity in melanoma and gastrointestinal stromal tumors warrants further investigation, and other phase I studies are ongoing. Further pharmacodynamic evaluation is required in these studies to evaluate the biological effects of TKI258.
Clinical Cancer Research 05/2008; 14(7):2075-81. · 7.74 Impact Factor
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Daniel E Lopes de Menezes,
Kimberly Denis-Mize,
Yan Tang,
Helen Ye,
John C Kunich,
Evelyn N Garrett,
Jing Peng,
Lawrence S Cousens,
Arnold B Gelb, Carla Heise,
Susan E Wilson,
Bahija Jallal,
Sharon L Aukerman
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ABSTRACT: Recombinant interleukin-2 (rIL-2) is a pleiotropic cytokine that activates select immune effector cell responses associated with antitumor activity, including antibody-dependent cellular cytotoxicity (ADCC). Rituximab is an anti-CD20 monoclonal antibody that activates ADCC in non-Hodgkin lymphoma (NHL). The ability of rIL-2 to augment rituximab-dependent tumor responses was investigated. The efficacy of rIL-2 in combination with rituximab was evaluated in 2 NHL tumor xenograft models: the CD20hi, rituximab-sensitive, low-grade Daudi model and the CD20lo, aggressive, rituximab-resistant Namalwa model. Combination of rIL-2 plus rituximab was synergistic in a rituximab-sensitive Daudi tumor model, as evidenced by significant tumor regressions and increased time to tumor progression, compared with rIL-2 and rituximab single agents. In contrast, rituximab-resistant Namalwa tumors were responsive to single-agent rIL-2 and showed an increased response when combined with rituximab. Using in vitro killing assays, rIL-2 was shown to enhance activity of rituximab by activating ADCC and lymphokine-activated killer activity. Additionally, the activity of rIL-2 plus rituximab F(ab')2 was similar to that of rIL-2 alone, indicating a critical role for immunoglobulin G1 Fc-FcgammaR-effector responses in mediating ADCC. Antiproliferative and apoptotic tumor responses, along with an influx of immune effector cells, were observed by immunohistochemistry. Collectively, the data suggest that rIL-2 mediates potent tumoricidal activity against NHL tumors, in part, through activation and trafficking of monocytes and natural killer cells to tumors. These data support the mechanistic and therapeutic rationale for combination of rIL-2 with rituximab in NHL clinical trials and for single-agent rIL-2 in rituximab-resistant NHL patients.
Journla of Immunotherapy 02/2007; 30(1):64-74. · 3.27 Impact Factor
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Esther Masih-Khan,
Suzanne Trudel, Carla Heise,
Zhihua Li,
Joshua Paterson,
Vincent Nadeem,
Ellen Wei,
David Roodman,
Jaime O Claudio,
P Leif Bergsagel,
A Keith Stewart
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ABSTRACT: Overexpression of fibroblast growth factor receptor 3 (FGFR3) is a hallmark of t(4;14) multiple myeloma (MM). To dissect the mechanism of FGFR3 oncogenesis in MM, we used 3 FGFR selective kinase inhibitors-CHIR258, PD173074, and SU5402-and FGFR3-specific siRNA to modulate FGFR3 activity. Conversely, the ligand FGF was used to stimulate FGFR3 function in human MM cells. The transcriptional response to FGFR3 modification was recorded, and gene expression changes common to all 5 modifiers were documented. Ten genes were commonly regulated. Macrophage inflammatory protein-1 alpha (MIP-1alpha) was the single most differentially altered gene. MIP-1 alpha promoter function, gene expression, and protein secretion were each down-regulated following inhibition of FGFR3 signaling. Down-regulation of MIP-1 alpha was not, however, observed following FGFR3 inhibition in MM cells with RAS mutations implicating RAS-MAPK in MIP-1 alpha regulation. As confirmation, inhibition of ERK1 also down-regulated MIP-1 alpha in FGFR3 inhibitor-resistant cells harboring RAS mutations. MIP-1 alpha is implicated in the survival and proliferation of MM cells and the pathogenesis of MM bone disease. Our observation is the first to directly link an initiating IgH translocation not only to MM-cell growth and survival but also to the disease-associated bone disease.
Blood 12/2006; 108(10):3465-71. · 9.90 Impact Factor
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ABSTRACT: 3-Benzimidazol-2-yl-1H-indazole analogs were developed as inhibitors of receptor tyrosine kinases (RTK). The synthesis and SAR of this series is reported.
Bioorganic & Medicinal Chemistry Letters 08/2006; 16(13):3595-9. · 2.55 Impact Factor
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Daniel E Lopes de Menezes,
Jing Peng,
Evelyn N Garrett,
Sharianne G Louie,
Sang H Lee,
Marion Wiesmann,
Yan Tang,
Lee Shephard,
Cheryl Goldbeck,
Yoko Oei,
Helen Ye,
Sharon L Aukerman, Carla Heise
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ABSTRACT: Fms-like tyrosine kinase 3 (FLT3) encodes a receptor tyrosine kinase (RTK) for which activating mutations have been identified in a proportion of acute myelogenous leukemia (AML) patients and associated with poor clinical prognosis. Given the relevance of FLT3 mutations in AML, we investigated the activity of CHIR-258, an orally active, multitargeted small molecule, with potent activity against FLT3 kinase and class III, IV, and V RTKs involved in endothelial and tumor cell proliferation in AML models.
CHIR-258 was tested on two human leukemic cell lines in vitro and in vivo with differing FLT3 mutational status [MV4;11 cells express FLT3 internal tandem duplications (ITD) versus RS4;11 cells with wild-type (WT) FLT3].
Antiproliferative activity of CHIR-258 against MV4;11 was approximately 24-fold greater compared with RS4;11, indicating more potent inhibition against cells with constitutively activated FLT3 ITD. Dose-dependent down modulation of receptor phosphorylation and downstream signaling [signal transducer and activator of transcription 5 (STAT5) and extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase] in MV4;11 cells with CHIR-258 confirmed the molecular mechanism of action. Target modulation of phospho-FLT3, phospho-STAT5, and phospho-ERK in MV4;11 tumors was achieved at biologically active doses of CHIR-258. Tumor regressions and eradication of AML cells from the bone marrow were shown in s.c. and bone marrow engraftment leukemic xenograft models. Tumor responses were characterized by decreased cellular proliferation and positive immunohistochemical staining for active caspase-3 and cleaved poly(ADP-ribose) polymerase, suggesting cell death was mediated in part via apoptosis.
Our data indicate that CHIR-258 may be an effective therapy in FLT3-associated AML and warrants clinical trials.
Clinical Cancer Research 08/2005; 11(14):5281-91. · 7.74 Impact Factor
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ABSTRACT: The t(4;14) translocation that occurs uniquely in a subset (15%) of patients with multiple myeloma (MM) results in the ectopic expression of the receptor tyrosine kinase (RTK), fibroblast growth factor receptor 3 (FGFR3). Inhibition of activated FGFR3 in MM cells induces apoptosis, validating FGFR3 as a therapeutic target in t(4;14) MM and encouraging the clinical development of FGFR3 inhibitors for the treatment of these patients, who have a poor prognosis. We describe here the characterization of a novel, small-molecule inhibitor of class III, IV, and V RTKs, CHIR-258, as an inhibitor of FGFR3. CHIR-258 potently inhibits FGFR3 with an inhibitory concentration of 50% (IC50) of 5 nM in in vitro kinase assays and selectively inhibited the growth of B9 cells and human myeloma cell lines expressing wild-type (WT) or activated mutant FGFR3. In responsive cell lines, CHIR-258 induced cytostatic and cytotoxic effects. Importantly, addition of interleukin 6 (IL-6) or insulin growth factor 1 (IGF-1) or coculture on stroma did not confer resistance to CHIR-258. In primary myeloma cells from t(4;14) patients, CHIR-258 inhibited downstream extracellular signal-regulated kinase (ERK) 1/2 phosphorylation with an associated cytotoxic response. Finally, therapeutic efficacy of CHIR-258 was demonstrated in a xenograft mouse model of FGFR3 MM. These studies support the clinical evaluation of CHIR-258 in MM.
Blood 05/2005; 105(7):2941-8. · 9.90 Impact Factor
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Sang Hoon Lee,
Daniel Lopes de Menezes,
Jayesh Vora,
Alex Harris,
Helen Ye,
Lara Nordahl,
Evelyn Garrett,
Emil Samara,
Sharon Lea Aukerman,
Arnold B Gelb, Carla Heise
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ABSTRACT: To evaluate the therapeutic and biological effects of CHIR-258, an orally bioavailable, potent inhibitor of class III-V receptor tyrosine kinases, in colon cancer models.
The pharmacologic activity of CHIR-258 was characterized by monitoring target modulation as well as by evaluating the antitumor and antiangiogenic effects in human colon xenograft models.
CHIR-258 inhibits vascular endothelial growth factor receptor 1/2, fibroblast growth factor receptor 1/3, and platelet-derived growth factor receptor beta (PDGFRbeta) and shows both antitumor and antiangiogenic activities in vivo. Treatment of KM12L4a human colon cancer cells with CHIR-258 resulted in a dose-dependent inhibition of vascular endothelial growth factor receptor 1 and PDGFRbeta phosphorylation and reduction of phosphorylated extracellular signal-regulated kinase (ERK) levels, indicating modulation of target receptors and downstream signaling. In vivo administration of CHIR-258 resulted in significant tumor growth inhibition and tumor regressions, including large, established tumors (500-1,000 mm(3)). Immunohistochemical analysis showed a reduction of phosphorylated PDGFRbeta and phosphorylated ERK in tumor cells after oral dosing with CHIR-258 compared with control tumors. These changes were accompanied by decreased tumor cell proliferation rate and reduced intratumoral microvessel density. CHIR-258 inhibited the phosphorylation of PDGFRbeta and ERK phosphorylation in tumors within 2 hours following dosing and the inhibitory activity was sustained for >24 hours. Significant antitumor activity was observed with intermittent dosing schedules, indicating a sustained biological activity.
These studies provide evidence that biological activity of CHIR-258 in tumors correlates with efficacy and aids in the identification of potential biomarkers of this multitargeted receptor tyrosine kinase inhibitor. CHIR-258 exhibits properties that make it a promising candidate for clinical development in a variety of solid and hematologic malignancies.
Clinical Cancer Research 05/2005; 11(10):3633-41. · 7.74 Impact Factor
