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1.
Curr Eye Res ; : 1-10, 2021 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-34674590

RESUMO

PURPOSE: Retinoblastoma is the most frequent intraocular cancer in children. It is also one of the most common causes for enucleation and carries a significant morbidity rate in affected individuals. Hence, studies on its pathophysiological and growth regulatory mechanisms are urgently needed to identify more effective novel therapeutics. METHODS: Using the Y79 retinoblastoma cell line, we investigated the electrophysiological and functional activities of the T-type voltage-gated calcium channel Cav3.1, that is constitutively expressed in these cells. We also analyzed the Akt and MAPK signaling pathways downstream of the epidermal growth factor receptor (EGFR) to understand the mechanism responsible for the inhibition of Cav3.1. RESULTS: We demonstrate that the EGFR inhibitor Afatinib significantly reduced cell viability and Cav3.1 mRNA expression and electrophysiological activity. At low concentrations (1 µM), Afatinib reduced the amplitude of Cav3.1 current density, whereas at a high concentration (10 µM), it completely abolished the voltage-gated calcium current. Our results show that inhibition of the MAPK pathway by a specific inhibitor VX-11e affected the Cav3.1 current in a dose-dependent manner. VX-11e (50 nM-1 µM) treatment reduced Cav3.1 current densities in Y79 cells, with complete abolishment of Cav3.1 current at higher concentrations (5 µM). We also demonstrate that the specific inhibition of the Akt kinase (using MK-2206) had no effect on the Cav3.1 currents. CONCLUSION: Our study provides a functional relationship between the MAPK pathway and EGFR signaling and indicates that the MAPK signaling pathway mediates the control of Cav3.1 by EGFR in retinoblastoma.

2.
Artigo em Inglês | MEDLINE | ID: mdl-33949932

RESUMO

BACKGROUND: Most children with recurrent metastatic solid tumors have high mortality rates. Recent studies have shown that proteasome inhibition leads to effective tumor killing in cells that have acquired treatment resistance and metastatic properties. OBJECTIVE: The purpose of this study was to test the potential of Carfilzomib (CFZ), a proteasome inhibitor, in refractory pediatric solid tumors, which is currently unknown. METHODS: A panel of pediatric solid tumor cell lines, including neuroblastoma, Ewing's sarcoma, osteosarcoma, rhabdomyosarcoma, and atypical teratoid rhabdoid tumor (ATRT), was used to evaluate the cytotoxic and proteasomal inhibitory effects of CFZ. A drug scheduling experiment was performed to determine the optimal dose and time to obtain effective cell killing. Combination studies of CFZ with chemotherapeutic drugs of different classes were performed to determine the extent of synergy. RESULTS: CFZ showed effective cytotoxicity against all cell lines tested (mean IC50 = 7nM, range = 1-20nM) and activity in a fluorophore-tagged cell-based proteasome assay. Drug scheduling experiments showed that the minimum exposure of 4-8 hours/day is needed for effective cumulative killing. CFZ, when combined with chemotherapeutic drugs of different classes, synergistically enhanced the extent of cell death. CONCLUSIONS: CFZ showed cytotoxic activity against all the solid pediatric cancer cell lines tested. This study provides initial in vitro data on the potential of CFZ to treat pediatric solid tumors and supports further investigations into the components of drug scheduling, biological correlates, and drug combinations for future early phase clinical trials in children.

3.
Cancer Gene Ther ; 28(7-8): 739-744, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32678303

RESUMO

Central nervous system (CNS) atypical teratoid/rhabdoid tumor (AT/RT) is a rare, aggressive tumor that most often affects very young children. The common decisive molecular defect in AT/RT has been shown to be a single genetic alteration, i.e., the loss of hSNF5 gene that encodes for a subunit of the SWI/SNF complex that modulates chromatin remodeling activities. As a result, AT/RT cells display unregulated cell proliferation due to the dysfunction of an important epigenetic control. We have previously demonstrated the preclinical efficacy of the oncolytic double-deleted vaccinia virus (VVDD) against AT/RT. Here we report the establishment of a modified VVDD engineered to express wild type hSNF5 gene. We show that this reconstructed vaccinia virus retains comparable infectivity and in vitro cytotoxicity of the parent strain. However, in addition, hSNF5-arming of VVDD results in a decreased cell cycle S phase population and down-regulation of cyclin D1. These findings suggest that hSNF5-arming of VVDD may increase the efficacy in the treatment of AT/RT and validates, as a proof-of-concept, an experimental approach to enhance the effective use of novel modified oncolytic viruses in the treatment of tumors with loss of a tumor suppressor gene function.

4.
Expert Opin Investig Drugs ; 29(11): 1199-1208, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32869671

RESUMO

INTRODUCTION: Triple negative breast cancer (TNBC) was once thought to be an insurmountable disease marked by a lack of targeted treatments. However, we are now witnessing the dawn of targeted therapies for TNBC in which progress has stemmed from an improved understanding of the components that make TNBC unique. The identification of biomarkers, such as BRCA1/2, PIK3CA and RSK2, have advanced the field remarkably and there is considerable interest in finding novel therapeutics for TNBC that offer durable clinical benefit with fewer adverse events. AREAS COVERED: We discuss phase I/II trials of new and emerging targeted therapies for TNBC, according to ClinicalTrials.gov up to June 2020. Although the emphasis is on ongoing and completed early phase trials, we also highlight pivotal studies that have led to the approval of new targeted classes of drugs for TNBC, with a focus on outcomes and common adverse events of each class of therapy. EXPERT OPINION: The way forward for TNBC treatment is through precision medicine. The use of novel agents matched with biomarkers to identify patients with the best chance of sustainable response offers new hope. We now have great potential for improving the outcomes for patients with TNBC.


Assuntos
Antineoplásicos/farmacologia , Terapia de Alvo Molecular , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Biomarcadores Tumorais/metabolismo , Drogas em Investigação/farmacologia , Feminino , Humanos , Medicina de Precisão , Neoplasias de Mama Triplo Negativas/patologia
6.
J Pediatr Hematol Oncol ; 41(6): e359-e370, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30702467

RESUMO

BACKGROUND: Recent studies have shown that cell cycle events are tightly controlled by complex and shared activities of a select group of kinases. Among these, polo-like kinases (Plks) are regulatory mitotic proteins that are overexpressed in several types of cancer and are associated with poor prognosis. MATERIALS AND METHODS: We have evaluated, in preclinical in vitro studies, the activity of a panel of Plk inhibitors against cell lines derived from refractory pediatric leukemia, as well as primary leukemia cells, in culture. Through in vitro growth inhibition studies, Western blot analysis for the expression and activation of key regulators of cell growth and survival and gene silencing studies, we specifically examined the ability of these agents to induce cytotoxicity through the activation of apoptosis and their capacity to interact and modulate the expression and phosphorylation of Aurora kinases. RESULTS: Our findings show that the various Plk-1 inhibitors in development show potential utility for the treatment of pediatric leukemia and exhibit a wide range of phosphorylation and target modulatory capabilities. Finally, we provide evidence for a complex interregulatory relationship between Plk-1 and Aurora kinases enabling the identification of synergy and biologic correlates of drug combinations targeting the 2 distinct enzyme systems. DISCUSSION: This information provide the rationale for the evaluation of Plk-1 as an effective target for therapeutics in refractory pediatric leukemia and indicate compensatory activities between Plk-1 and Aurora kinases, providing insight into some of the complex mechanisms involved in the process of cell division.


Assuntos
Apoptose , Aurora Quinases/antagonistas & inibidores , Azepinas/farmacologia , Proteínas de Ciclo Celular/antagonistas & inibidores , Leucemia/patologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Pteridinas/farmacologia , Pirimidinas/farmacologia , Proliferação de Células , Humanos , Leucemia/tratamento farmacológico , Leucemia/enzimologia , Células Tumorais Cultivadas
7.
Target Oncol ; 13(6): 779-793, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30446871

RESUMO

BACKGROUND: Leukemia accounts for 30% of all childhood cancers and although the survival rate for pediatric leukemia has greatly improved, relapse is a major cause of treatment failure. Therefore, the development and introduction of novel therapeutics to treat relapsed pediatric leukemia is urgently needed. The proteasome inhibitor bortezomib has been shown to be effective against adult hematological malignancies such as multiple myeloma and lymphoma, but is frequently associated with the development of resistance. Carfilzomib is a next-generation proteasome inhibitor that has shown promising results against refractory adult hematological malignancies. OBJECTIVE: Carfilzomib has been extensively studied in adult hematological malignancies, providing the rationale for evaluating proof-of-concept activity of carfilzomib in pediatric leukemia. METHODS: The effects of carfilzomib on pediatric leukemia cell lines and primary pediatric leukemia patient samples were investigated in vitro using the alamar blue cytotoxicity assay, western blotting, and a proteasome activity assay. Synergy with commonly used anticancer drugs was determined by calculation of combination indices. RESULTS: In vitro preclinical data show pharmacologically relevant concentrations of carfilzomib are cytotoxic to pediatric leukemia cell lines and primary pediatric leukemia cells. Target modulation studies validate the effective inhibition of the proteasome and induction of apoptosis. We also identify agents that have effective synergy with carfilzomib in these cells. CONCLUSIONS: Our data provide pre-clinical information that can be incorporated into future early-phase clinical trials for the assessment of carfilzomib as a treatment for children with refractory hematological malignancies.


Assuntos
Leucemia/tratamento farmacológico , Oligopeptídeos/farmacologia , Inibidores de Proteassoma/farmacologia , Adolescente , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Bortezomib/farmacologia , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Criança , Sinergismo Farmacológico , Feminino , Humanos , Lactente , Leucemia/metabolismo , Leucemia/patologia , Masculino , Terapia de Alvo Molecular , Oligopeptídeos/administração & dosagem
8.
Curr Cancer Drug Targets ; 17(6): 569-584, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27875952

RESUMO

BACKGROUND: Neuroblastoma (NB) constitutes about 8% of all childhood tumors, yet accounts for more than 15% of deaths, with an unacceptable overall survival rate. These rates are despite the current multimodal therapeutic approaches involving surgery, radiation, chemotherapy and myeloablation with hematopoietic stem cell rescue. Hence, efforts have intensified to identify new targets and novel therapeutic approaches to improve cure rates in these children. Numerous new agents for adult malignancies are developed and evaluated for cancer each year, providing an invaluable resource, with the added advantage of available pharmacologic and toxicity data for consideration. METHODS: To identify potential therapeutic targets, we screened a small molecule library of 151 small kinase inhibitors against NB cell lines. Based on our initial screening data, we further examined the potential of Bcr-Abl targeting small molecule inhibitors to affect the growth and survival of NB cells. RESULTS: There is diverse activity among the currently available Bcr-Abl inhibitors, possibly reflecting the molecular heterogeneity and off-target activity in each combination. In depth analyses of ponatinib, an oral multi-target kinase inhibitor and effective agent in the treatment of refractory Philadelphia chromosome (Ph) positive leukemia, show growth inhibition at sub-micromolar concentrations. In addition, we also identified the potential of this agent to interfere with insulin-like growth factor-1 receptor (IGF-1R) signaling pathways and Src activity, inhibit cell migration and induce apoptosis. CONCLUSION: Our findings provide initial data on ponatinib's potential to target key growth regulatory pathways and provide the rationale for further studies and evaluation in future early phase clinical trials for the treatment of refractory NB.


Assuntos
Antineoplásicos/farmacologia , Neuroblastoma/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Bibliotecas de Moléculas Pequenas/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Humanos , Imidazóis/farmacologia , Fator de Crescimento Insulin-Like I/farmacologia , Terapia de Alvo Molecular , Neuroblastoma/metabolismo , Neuroblastoma/patologia , Fosforilação/efeitos dos fármacos , Piridazinas/farmacologia , Receptor IGF Tipo 1/metabolismo , Quinases da Família src/metabolismo
9.
Neuro Oncol ; 17(6): 822-31, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25395461

RESUMO

BACKGROUND: Neurocutaneous melanocytosis (NCM) is a rare congenital disorder that presents with pigmented cell lesions of the brain or leptomeninges in children with large or multiple congenital melanocytic nevi. Although the exact pathological processes involved are currently unclear, NCM appears to arise from an abnormal development of melanoblasts or melanocyte precursors. Currently, it has an extremely poor prognosis due to rapid disease progression and lack of effective treatment modalities. METHODS: In this study, we report on an experimental approach to examining NCM cells by establishing subcutaneous tumors in nude mice, which can be further expanded for conducting molecular and drug sensitivity experiments. RESULTS: Analysis of the NRAS gene-coding sequences of an established NCM cell line (YP-MEL) and NCM patient cells revealed heterogeneity in NRAS Q61K that activated mutation and possibly consequential differential sensitivity to MEK inhibition. Gene expression studies were performed to compare the molecular profiles of NCM cells with normal skin fibroblasts. In vitro cytotoxicity screens of libraries of targeted small-molecule inhibitors revealed prospective agents for further evaluation. CONCLUSIONS: Our studies provide an experimental platform for the generation of NCM cells for preclinical studies and the production of molecular and in vitro data with which to identify druggable targets for the treatment.


Assuntos
Antineoplásicos/administração & dosagem , Melanose/tratamento farmacológico , Melanose/genética , Síndromes Neurocutâneas/tratamento farmacológico , Síndromes Neurocutâneas/genética , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Animais , Antineoplásicos/uso terapêutico , Pré-Escolar , GTP Fosfo-Hidrolases/genética , Xenoenxertos/efeitos dos fármacos , Xenoenxertos/patologia , Humanos , Masculino , Melanose/patologia , Proteínas de Membrana/genética , Camundongos , Camundongos Nus , Mutação , Síndromes Neurocutâneas/patologia , Transdução de Sinais/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/administração & dosagem , Bibliotecas de Moléculas Pequenas/uso terapêutico , Transcriptoma , Células Tumorais Cultivadas
10.
PLoS One ; 9(7): e102741, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25048812

RESUMO

Leukemia is the most common pediatric malignancy, constituting more than 30% of all childhood cancers. Although cure rates have improved greatly, approximately one in five children relapse and poor survival rates post relapse remain a challenge. Given this, more effective and innovative therapeutic strategies are needed in order to improve prognosis. Aurora kinases, a family of serine/threonine kinases essential for the regulation of several mitotic processes, have been identified as potential targets for cancer therapeutics. Elevated expression of Aurora kinases has been demonstrated in several malignancies and is associated with aberrant mitotic activity, aneuploidy and alterations in chromosomal structure and genome instability. Based on this rationale, a number of small molecule inhibitors have been formulated and advanced to human studies in the recent past. A comparative analysis of these agents in cytotoxicity and target modulation analyses against a panel of leukemia cells provides novel insights into the unique mechanisms and codependent activity pathways involved in targeting Aurora kinases, constituting a distinctive preclinical experimental framework to identify appropriate agents and combinations in future clinical studies.


Assuntos
Aurora Quinases/antagonistas & inibidores , Leucemia/tratamento farmacológico , Leucemia/enzimologia , Inibidores de Proteínas Quinases/uso terapêutico , Apoptose/efeitos dos fármacos , Aurora Quinases/genética , Aurora Quinases/metabolismo , Linhagem Celular Tumoral , Criança , Terapia Genética , Humanos , Leucemia/genética , Terapia de Alvo Molecular , Interferência de RNA , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/uso terapêutico
11.
Mol Oncol ; 7(5): 944-54, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23816608

RESUMO

BACKGROUND: Previous studies have shown successful antitumor effects of systemically delivered double-deleted vaccinia virus (vvDD) against a number of adult tumor models, including glioma, colon and ovarian cancers. The purpose of this study was to investigate the oncolytic potential of vvDD against a panel of cell lines representative of pediatric solid tumors that are currently difficult to cure. METHODS: Cell lines derived from central nervous system atypical teratoid rhabdoid tumor (AT/RT) (BT12, BT16 and KCCF1), sarcoma (143B, HOS, RD and RH30), and neuroblastoma (SKNAS, SKNBE2, IMR-5 and IMR-32) were examined for vvDD mediated cytotoxicity defined by virus expansion followed by loss of tumor cell viability. The normal human fibroblast cell line HS68 was used as a control. Next, relevant orthotopic, subcutaneous and lung metastasis xenograft models were treated with intravenous doses of live vvDD or killed virus controls (DV). Tumor growth inhibition and viral replication were quantified and survival outcomes of these animals were assessed. RESULTS: vvDD was able to infect and kill nine of eleven of the pediatric tumor cells (81.8%) in vitro. In xenograft models, intravenous administration of a single dose of vvDD significantly inhibited the growth of tumors and prolonged the survival of intracranial and metastatic tumors. CONCLUSIONS: Oncolytic vvDD administered i.v. shows activity in preclinical models of pediatric malignancies that are resistant to many currently available treatments. Our data support further evaluation of vvDD virotherapy for refractory pediatric solid tumors.


Assuntos
Neoplasias/terapia , Terapia Viral Oncolítica/métodos , Vírus Vaccinia/fisiologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Sobrevivência Celular/fisiologia , Feminino , Humanos , Lactente , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/secundário , Neoplasias Pulmonares/terapia , Masculino , Camundongos , Camundongos Nus , Camundongos SCID , Neoplasias/genética , Neuroblastoma/genética , Neuroblastoma/terapia , Sarcoma/complicações , Sarcoma/genética , Sarcoma/terapia , Vírus Vaccinia/genética , Ensaios Antitumorais Modelo de Xenoenxerto
12.
Mol Oncol ; 7(3): 497-512, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23375777

RESUMO

Despite intensifying multimodal treatments, children with central nervous system atypical teratoid/rhabdoid tumor (CNS ATRT) continue to endure unacceptably high mortality rates. At present, concerted efforts are focusing on understanding the characteristic INI1 mutation and its implications for the growth and survival of these tumors. Additionally, pharmaceutical pipeline libraries constitute a significant source of potential agents that can be taken to clinical trials in a timely manner. However, this process requires efficient target validation and relevant preclinical studies. As an initial screening approach, a panel of 129 small molecule inhibitors from multiple pharmaceutical pipeline libraries was tested against three ATRT cell lines by in vitro cytotoxicity assays. Based on these data, agents that have strong activity and corresponding susceptible cellular pathways were identified. Target modulation, antibody array analysis, drug combination and in vivo xenograft studies were performed on one of the pathway inhibitors found in this screening. Approximately 20% of agents in the library showed activity with IC(50) values of 1 µM or less and many showed IC(50) values less than 0.05 µM. Intra cell line variability was also noted among some of the drugs. However, it was determined that agents capable of affecting pathways constituting ErbB2, mTOR, proteasomes, Hsp90, Polo like kinases and Aurora kinases were universally effective against the three ATRT cell lines. The first target selected for further analysis, the inhibition of ErbB2-EGFR pathway by the small molecule inhibitor lapatinib, indicated inhibition of cell migration properties and the initiation of apoptosis. Synergy between lapatinib and IGF-IR inhibition was also demonstrated by combination index (CI) values. Xenograft studies showed effective antitumor activity of lapatinib in vivo. We present an experimental approach to identifying agents and drug combinations for future clinical trials and provide evidence for the potential of lapatinib as an effective agent in the context of the biology and heterogeneity of its targets in ATRT.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Receptores ErbB/metabolismo , Quinazolinas/uso terapêutico , Receptor ErbB-2/metabolismo , Tumor Rabdoide/tratamento farmacológico , Animais , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Neoplasias do Sistema Nervoso Central/metabolismo , Neoplasias do Sistema Nervoso Central/patologia , Criança , Feminino , Humanos , Lactente , Lapatinib , Masculino , Camundongos , Terapia de Alvo Molecular , Tumor Rabdoide/metabolismo , Tumor Rabdoide/patologia , Transdução de Sinais/efeitos dos fármacos
13.
Leuk Lymphoma ; 54(7): 1505-16, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23176524

RESUMO

Acute lymphoblastic leukemia (ALL) is one of the most prevelant pediatric malignancies. Although cure rates have improved in recent decades, approximately one in five children relapse, and survival rates post-relapse remain low. Therefore, more effective and innovative therapeutic strategies are needed in order to improve the outcome in these children. Aurora kinases, a family of serine/threonine kinases essential for regulated mitosis, are overexpressed in many forms of cancer, and have been identified as potential targets for cancer therapeutics. Based on this premise, we evaluated the activity of the Aurora-A/B inhibitor AT9283 against pediatric leukemia cells. It was found that AT9283 significantly inhibited the growth and survival of cell lines derived from patients with pediatric leukemia. Specifically, AT9283 promoted Flt-3 dephosphorylation, inhibiting the activity of downstream effectors such as Erk and Mek. In addition, apoptotic markers were also identified, providing a panel of markers for biological correlative analysis for drug activity. Lastly, drug combination studies demonstrated the potential of several novel and conventional agents to synergize with AT9283, including apicidin, 17-allylamino-17-demethoxygeldanamycin (17-AAG) and doxorubicin. These data provide a rationale for further studies and the formulation of a clinical trial of AT9283 for the treatment of refractory pediatric ALL.


Assuntos
Antineoplásicos/farmacologia , Aurora Quinases/antagonistas & inibidores , Leucemia-Linfoma Linfoblástico de Células Precursoras/enzimologia , Inibidores de Proteínas Quinases/farmacologia , Antineoplásicos/toxicidade , Apoptose/efeitos dos fármacos , Benzimidazóis/farmacologia , Benzimidazóis/toxicidade , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Criança , Humanos , Concentração Inibidora 50 , Janus Quinase 2/antagonistas & inibidores , Poliploidia , Inibidores de Proteínas Quinases/toxicidade , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Ureia/análogos & derivados , Ureia/farmacologia , Ureia/toxicidade , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores
14.
Stem Cells ; 30(6): 1064-75, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22415968

RESUMO

Glioblastoma multiforme (GBM) ranks among the deadliest types of cancer and given these new therapies are urgently needed. To identify molecular targets, we queried a microarray profiling 467 human GBMs and discovered that polo-like kinase 1 (PLK1) was highly expressed in these tumors and that it clustered with the proliferative subtype. Patients with PLK1-high tumors were more likely to die from their disease suggesting that current therapies are inactive against such tumors. This prompted us to examine its expression in brain tumor initiating cells (BTICs) given their association with treatment failure. BTICs isolated from patients expressed 110-470 times more PLK1 than normal human astrocytes. Moreover, BTICs rely on PLK1 for survival because the PLK1 inhibitor BI2536 inhibited their growth in tumorsphere cultures. PLK1 inhibition suppressed growth, caused G(2) /M arrest, induced apoptosis, and reduced the expression of SOX2, a marker of neural stem cells, in SF188 cells. Consistent with SOX2 inhibition, the loss of PLK1 activity caused the cells to differentiate based on elevated levels of glial fibrillary acidic protein and changes in cellular morphology. We then knocked glial fibrillary acidic protein (GFAP) down SOX2 with siRNA and showed that it too inhibited cell growth and induced cell death. Likewise, in U251 cells, PLK1 inhibition suppressed cell growth, downregulated SOX2, and induced cell death. Furthermore, BI2536 delayed tumor growth of U251 cells in an orthotopic brain tumor model, demonstrating that the drug is active against GBM. In conclusion, PLK1 level is elevated in GBM and its inhibition restricts the growth of brain cancer cells.


Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Proteínas de Ciclo Celular/antagonistas & inibidores , Glioblastoma/tratamento farmacológico , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Pteridinas/farmacologia , Fatores de Transcrição SOXB1/deficiência , Animais , Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/enzimologia , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Progressão da Doença , Glioblastoma/enzimologia , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Camundongos , Terapia de Alvo Molecular , Células-Tronco Neurais , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Análise de Sobrevida , Transfecção
15.
J Neurooncol ; 107(1): 111-9, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21971736

RESUMO

The central nervous system Atypical Teratoid/Rhabdoid Tumor (CNS AT/RT) is a highly malignant neoplasm that commonly affects infants and young children, and has an extremely poor prognosis. Recently, a small subset of ion channels have been found to be over-expressed in a variety of malignant cells, thus emerging as potential therapeutic targets for difficult to treat tumors. We have studied the electrophysiological properties of AT/RT cell lines with particular attention to cell volume sensitive ion channels (VSC). This class of membrane proteins can play a fundamental role in cellular processes relevant to tumor development. We have found that chloride selective VSCs are particularly active in AT/RT cell lines, compared to non-tumor cells. We evaluated specific inhibitors for activity against chloride selective VSCs and consequently for their ability to inhibit the growth and survival of AT/RT cells in vitro. The results demonstrated that the extent of volume sensitive membrane current inhibition by these agents was correlated with their potency in AT/RT cell growth inhibition in vitro. In addition, we showed that ion channel inhibition enhanced the activity of certain anti-neoplastic agents, suggesting its value in effective drug combination protocols. Results presented provide preliminary in vitro data for possible evaluation of distinct ion channels as plausible therapeutic targets in the treatment of AT/RT.


Assuntos
Antineoplásicos/farmacologia , Neoplasias Encefálicas/metabolismo , Canais de Cloreto/metabolismo , Canais de Potássio/metabolismo , Tumor Rabdoide/metabolismo , Teratoma/metabolismo , Ácido 4,4'-Di-Isotiocianoestilbeno-2,2'-Dissulfônico/farmacologia , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Astrócitos/citologia , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Neoplasias Encefálicas/tratamento farmacológico , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Criança , Canais de Cloreto/antagonistas & inibidores , Quimioterapia Combinada , Eletrofisiologia , Glibureto/farmacologia , Humanos , Hipoglicemiantes/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Ácido Niflúmico/farmacologia , Canais de Potássio/química , Tumor Rabdoide/tratamento farmacológico , Teratoma/tratamento farmacológico
16.
Cancer Cell Int ; 11(1): 44, 2011 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-22206574

RESUMO

BACKGROUND: Currently, Atypical Teratoid Rhabdoid Tumor (AT/RT) constitutes one of the most difficult to treat malignancies in pediatrics. Hence, new knowledge of potential targets for therapeutics and the development of novel treatment approaches are urgently needed. We have evaluated the presence of cytokine pathways and the effects of two clinically available multi-tyrosine kinase inhibitors for cytotoxicity, target modulation and drug combinability against AT/RT cell lines. RESULTS: AT/RT cell lines expressed measurable quantities of VEGF, FGF, PDGF and SDF-1, although the absolute amounts varied between the cell lines. The targeted receptor tyrosine kinase inhibitor sorafenib inhibited the key signaling molecule Erk, which was activated following the addition of own conditioned media, suggesting the existence of autocrine/paracrine growth stimulatory pathways. The multi-tyrosine kinase inhibitors sorafenib and sunitinib also showed significant growth inhibition of AT/RT cells and their activity was enhanced by combination with the topoisomerase inhibitor, irinotecan. The loss of cytoplasmic NF-kappa-B in response to irinotecan was diminished by sorafenib, providing evidence for a possible benefit for this drug combination. CONCLUSIONS: In addition to previously described involvement of insulin like growth factor (IGF) family of cytokines, a multitude of other growth factors may contribute to the growth and survival of AT/RT cells. However, consistent with the heterogeneous nature of this tumor, quantitative and qualitative differences may exist among different tumor samples. Multi-tyrosine kinase inhibitors appear to have effective antitumor activity against all cell lines studied. In addition, the target modulation studies and drug combinability data provide the groundwork for additional studies and support the evaluation of these agents in future treatment protocols.

17.
Cell Physiol Biochem ; 28(6): 1169-80, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22179005

RESUMO

Acute Myeloid Leukemia (AML) accounts for approximately one fifth of all childhood leukemia yet is responsible for a significant proportion of morbidity and mortality in this population. For this reason, research to identify novel targets for the development of effective AML therapeutics has intensified in the recent past. The THP-1 cell line, which was originally established from an infant diagnosed with AML, provides an experimental model for functional, pre-clinical therapeutics and target identification studies of AML. Here we show the expression of the voltage gated potassium channel Kv11.1 in THP-1 cells as opposed to normal hematopoietic stem cells. In addition, curcumin, a natural polyphenol derived from the plant Curcuma longa, effectively blocked Kv11.1 activity and also inhibited the proliferation of these cells. Curcumin was rapidly internalized by THP-1 cells and possibly exerts potential growth inhibitory activity by interacting with intracellular epitopes of the ion channel. Inhibition of ionic currents carried by Kv11.1 resulted in depolarization of cell membrane potential. We propose that the inhibition of Kv11.1 activity by curcumin may lead to interference with leukemic cell physiology and consequently the suppression of survival and proliferation of AML cells.


Assuntos
Antineoplásicos/farmacologia , Curcumina/farmacologia , Canais de Potássio Éter-A-Go-Go/antagonistas & inibidores , Potássio/metabolismo , Antineoplásicos/uso terapêutico , Linhagem Celular , Proliferação de Células , Curcuma/química , Curcumina/uso terapêutico , Canal de Potássio ERG1 , Canais de Potássio Éter-A-Go-Go/metabolismo , Canais de Potássio Éter-A-Go-Go/fisiologia , Humanos , Lactente , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/fisiologia
18.
Onco Targets Ther ; 4: 149-68, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21949608

RESUMO

Despite significant progress made in the overall cure rate, the prognosis for relapsed and refractory malignancies in children remains extremely poor. Hence, there is an urgent need for studies that enable the timely selection of appropriate agents for Phase I clinical studies. The Pediatric Oncology Experimental Therapeutics Investigators' Consortium (POETIC) is systematically evaluating libraries of known and novel compounds for activity against subsets of high-risk pediatric malignancies with defined molecular aberrations for future clinical development. In this report, we describe the in-vitro activity of a diverse panel of approved oncology drugs against MLL-rearranged pediatric leukemia cell lines. Agents in the Approved Oncology Drug Set II (National Cancer Institute/National Institutes of Health Developmental Therapeutics Program) were evaluated by in-vitro cytotoxicity assays in pediatric acute lymphoblastic leukemia and acute myeloid leukemia cell lines with MLL gene rearrangements. Validation studies were carried out with patient leukemia cells in culture. Comparative analysis for toxicity against nonmalignant cells was evaluated in normal bone marrow stromal cells and normal human lymphocytes. Results from this study show that 42 of the 89 agents tested have measurable cytotoxicity against leukemia cells, and among these, 12 were effective against all five MLL-rearranged cell lines (IC(50) [half maximal inhibitory concentration] < 1 µM). These 12 agents include cladribine, dactinomycin, daunorubicin, docetaxel, etoposide, gemcitabine, mitomycin C, mitoxantrone, teniposide, topotecan, triethylenemelamine, and vinblastine. We show that the Approved Oncology Drug Set II contains a number of agents with potent antileukemic activity in the tested cell lines. As approved drugs, these agents have been used in clinical settings for many years for other malignancies, thus their toxicity profile, pharmacokinetics, and other properties are readily available. Further evaluation of their use in future clinical trials for pediatric leukemia with MLL abnormalities should be considered.

19.
Leuk Res ; 35(12): 1649-57, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21798596

RESUMO

Although recent decades have seen a significant improvement in the treatment outcome of leukemia in the pediatric population, those who are treated for relapsed disease still face significant morbidity and mortality. However, current salvage regimens are often assembled with agents that have similar mode of activity as the chemotherapeutics used in the initial treatment. Hence, novel therapeutic agents that are capable of distinct and diverse mechanisms of activity in, now resistant, leukemia cells are of great interest. We have investigated the opioid agonist methadone for its anti-leukemic activity, initially reported in studies with cell lines derived from adult patients. Our findings show that, compared to normal cells, methadone has enhanced cytotoxicity against specimens and cell lines established from refractory childhood leukemia. In addition, methadone's activity synergized with that of the anti-Bcl-2 agent ABT-737 and was characterized by the induction of distinct changes in tumor cell mitochondria. Data presented also identify biological correlates and a potential mechanism for methadone activity by its effects on Mcl-1 and other members of the apoptosis cascade. We provide mechanistic data for the therapeutic potential of a family of agents that is largely unexplored for anti-leukemic activity.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Compostos de Bifenilo/farmacologia , Metadona/farmacologia , Nitrofenóis/farmacologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Sulfonamidas/farmacologia , Fatores Etários , Idade de Início , Analgésicos Opioides/administração & dosagem , Analgésicos Opioides/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Compostos de Bifenilo/administração & dosagem , Criança , Pré-Escolar , Avaliação Pré-Clínica de Medicamentos , Sinergismo Farmacológico , Feminino , Humanos , Lactente , Masculino , Metadona/administração & dosagem , Nitrofenóis/administração & dosagem , Piperazinas/administração & dosagem , Piperazinas/farmacologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/epidemiologia , Cultura Primária de Células , Sulfonamidas/administração & dosagem , Resultado do Tratamento , Células Tumorais Cultivadas , Regulação para Cima/efeitos dos fármacos
20.
Fetal Pediatr Pathol ; 30(3): 177-88, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21355677

RESUMO

Growth of tumor cells is often a function of deregulated growth factor receptors and their corresponding intracellular signalling molecules. The dissociable antibody staining arrays have the versatility to rapidly identify the expression, activation, and localization of such molecules and pathways in biopsy specimens. This report describes a protocol to quantify the activity of a panel of signalling molecules in Wilms tumor biopsy specimens and surrounding nonmalignant renal cells. We propose that this technique can be used to rapidly identify multiple markers and may aid in the study of aberrant growth regulatory mechanisms and potential targets for therapeutics from pathologic specimens.


Assuntos
Peptídeos e Proteínas de Sinalização Intercelular/análise , Neoplasias Renais/química , Proteínas de Neoplasias/análise , Análise Serial de Tecidos/métodos , Tumor de Wilms/química , Biópsia , Criança , Humanos , Imuno-Histoquímica , Peptídeos e Proteínas de Sinalização Intracelular/análise , Receptores Proteína Tirosina Quinases/análise , Coloração e Rotulagem
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