RESUMO
Umbilical cord blood (UCB) engraftment is in part limited by graft cell dose, generally one log less than that of bone marrow (BM)/peripheral blood (PB) cell grafts. Strategies toward increasing hematopoietic stem/progenitor cell (HSPC) homing to BM have been assessed to improve UCB engraftment. Despite recent progress, a complete understanding of how HSPC homing and engraftment are regulated is still elusive. We provide evidence that blocking erythropoietin (EPO)-EPO receptor (R) signaling promotes homing to BM and early engraftment of UCB CD34+ cells. A significant population of UCB CD34+ HSPC expresses cell surface EPOR. Exposure of UCB CD34+ HSPC to EPO inhibits their migration and enhances erythroid differentiation. This migratory inhibitory effect was reversed by depleting EPOR expression on HSPC. Moreover, systemic reduction in EPO levels by hyperbaric oxygen (HBO) used in a preclinical mouse model and in a pilot clinical trial promoted homing of transplanted UCB CD34+ HSPC to BM. Such a systemic reduction of EPO in the host enhanced myeloid differentiation and improved BM homing of UCB CD34+ cells, an effect that was overcome with exogenous EPO administration. Of clinical relevance, HBO therapy before human UCB transplantation was well-tolerated and resulted in transient reduction in EPO with encouraging engraftment rates and kinetics. Our studies indicate that systemic reduction of EPO levels in the host or blocking EPO-EPOR signaling may be an effective strategy to improve BM homing and engraftment after allogeneic UCB transplantation. This clinical trial was registered at www.ClinicalTrials.gov (#NCT02099266).
Assuntos
Transplante de Células-Tronco de Sangue do Cordão Umbilical , Eritropoetina/metabolismo , ADP-Ribosil Ciclase 1/metabolismo , Adolescente , Adulto , Idoso , Animais , Antígenos CD34/metabolismo , Diferenciação Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Quimiocina CXCL12/farmacologia , Quimerismo , Estudos de Coortes , Transplante de Células-Tronco de Sangue do Cordão Umbilical/efeitos adversos , Feminino , Doença Enxerto-Hospedeiro/etiologia , Humanos , Oxigenoterapia Hiperbárica , Masculino , Camundongos , Pessoa de Meia-Idade , Células Mieloides/citologia , Células Mieloides/efeitos dos fármacos , Células Mieloides/metabolismo , Receptores da Eritropoetina/metabolismo , Análise de Sobrevida , Condicionamento Pré-Transplante , Resultado do Tratamento , Adulto JovemRESUMO
The 90-kDa heat-shock protein (Hsp90) assists in the proper folding of numerous mutated or overexpressed signal transduction proteins that are involved in cancer. Inhibiting Hsp90 consequently is an attractive strategy for cancer therapy as the concomitant degradation of multiple oncoproteins may lead to effective antineoplastic agents. Here we report a novel C-terminal Hsp90 inhibitor, designated KU675, that exhibits potent antiproliferative and cytotoxic activity along with client protein degradation without induction of the heat-shock response in both androgen-dependent and -independent prostate cancer cell lines. In addition, KU675 demonstrates direct inhibition of Hsp90 complexes as measured by the inhibition of luciferase refolding in prostate cancer cells. In direct binding studies, the internal fluorescence signal of KU675 was used to determine the binding affinity of KU675 to recombinant Hsp90α, Hsp90ß, and Hsc70 proteins. The binding affinity (Kd) for Hsp90α was determined to be 191 µM, whereas the Kd for Hsp90ß was 726 µM, demonstrating a preference for Hsp90α. Western blot experiments with four different prostate cancer cell lines treated with KU675 supported this selectivity by inducing the degradation of Hsp90α -: dependent client proteins. KU675 also displayed binding to Hsc70 with a Kd value at 76.3 µM, which was supported in cellular by lower levels of Hsc70-specific client proteins on Western blot analyses. Overall, these findings suggest that KU675 is an Hsp90 C-terminal inhibitor, as well as a dual inhibitor of Hsc70, and may have potential use for the treatment of cancer.
Assuntos
Antineoplásicos/farmacologia , Cumarínicos/farmacologia , Proteínas de Choque Térmico HSC70/antagonistas & inibidores , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Novobiocina/análogos & derivados , Compostos de Fenilureia/farmacologia , Neoplasias da Próstata/metabolismo , Antineoplásicos/síntese química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cumarínicos/síntese química , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Masculino , Compostos de Fenilureia/síntese química , Ligação ProteicaRESUMO
Delayed engraftment and graft failure represent major obstacles to successful umbilical cord blood (UCB) transplantation. Herein, we evaluated the use of hyperbaric oxygen (HBO) therapy as an intervention to improve human UCB stem/progenitor cell engraftment in an immune deficient mouse model. Six- to eight-week old NSG mice were sublethally irradiated 24 hours prior to CD34⺠UCB cell transplant. Irradiated mice were separated into a non-HBO group (where mice remained under normoxic conditions) and the HBO group (where mice received 2 hours of HBO therapy; 100% oxygen at 2.5 atmospheres absolute). Four hours after completing HBO therapy, both groups intravenously received CD34⺠UCB cells that were transduced with a lentivirus carrying luciferase gene and expanded for in vivo imaging. Mice were imaged and then sacrificed at one of 10 times up to 4.5 months post-transplant. HBO treated mice demonstrated significantly improved bone marrow, peripheral blood, and spleen retention and subsequent engraftment. In addition, HBO significantly improved peripheral, spleen and bone marrow engraftment of human myeloid and B-cell subsets. In vivo imaging demonstrated that HBO mice had significantly higher ventral and dorsal bioluminescence values. These studies suggest that HBO treatment of NSG mice prior to UCB CD34⺠cell infusion significantly improves engraftment.
Assuntos
Subpopulações de Linfócitos B/citologia , Transplante de Células-Tronco de Sangue do Cordão Umbilical , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto , Oxigenoterapia Hiperbárica , Animais , Antígenos CD34/genética , Antígenos CD34/imunologia , Subpopulações de Linfócitos B/imunologia , Células da Medula Óssea/citologia , Células da Medula Óssea/imunologia , Feminino , Expressão Gênica , Genes Reporter , Rejeição de Enxerto/imunologia , Humanos , Injeções Intravenosas , Luciferases/genética , Luciferases/metabolismo , Camundongos , Camundongos Endogâmicos , Baço/citologia , Baço/imunologia , Transplante Heterólogo , Irradiação Corporal TotalRESUMO
Since Hsp90 modulates all six hallmarks of cancer simultaneously, it has become an attractive target for the development of cancer chemotherapeutics. In an effort to develop more efficacious compounds for Hsp90 inhibition, novobiocin analogues were prepared by replacing the central coumarin core with naphthalene, quinolinone, and quinoline surrogates. These modifications allowed for modification of the 2-position, which was previously unexplored. Biological evaluation of these compounds suggests a hydrophobic pocket about the 2-position of novobiocin. Anti-proliferative activities of these analogues against multiple cancer cell lines identified 2-alkoxyquinoline derivatives to exhibit improved activity.
Assuntos
Cumarínicos/química , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Novobiocina/química , Novobiocina/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Células MCF-7 , Naftalenos/química , Novobiocina/síntese química , Ligação Proteica/efeitos dos fármacos , Quinolinas/químicaRESUMO
Heat shock protein 90 (Hsp90) has emerged as a promising therapeutic target for the treatment of cancer. Several Hsp90 inhibitors have entered clinical trials. However, some toxicological detriments have arisen, such as cardiotoxicity resulting from hERG inhibition following the administration of Hsp90 inhibitors. We sought to investigate this toxicity as hERG has been previously reported as a client protein that depends upon Hsp90 for its maturation and functional trafficking. In this study we show that hERG depends upon a single Hsp90 isoform. hERG preferentially co-immunoprecipitated with Hsp90α, and genetic knockdown of Hsp90α, but not Hsp90ß, resulted in a trafficking-defective hERG channel. This study demonstrates the importance of delineating the isoform dependence of Hsp90 client proteins and provides rationale for the design of isoform-selective Hsp90 inhibitors that avoid detrimental effects.
Assuntos
Canais de Potássio Éter-A-Go-Go/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Isoformas de Proteínas/metabolismo , Western Blotting , Linhagem Celular , Densitometria , Canais de Potássio Éter-A-Go-Go/genética , Proteínas de Choque Térmico HSP90/genética , Humanos , Imunoprecipitação , Espectrometria de Massas , Modelos Biológicos , Ligação Proteica , Isoformas de Proteínas/genética , Transporte Proteico/fisiologia , RNA Interferente PequenoRESUMO
BACKGROUND: The molecular chaperone, heat shock protein 90 (Hsp90) has been shown to be overexpressed in a number of cancers, including prostate cancer, making it an important target for drug discovery. Unfortunately, results with N-terminal inhibitors from initial clinical trials have been disappointing, as toxicity and resistance resulting from induction of the heat shock response (HSR) has led to both scheduling and administration concerns. Therefore, Hsp90 inhibitors that do not induce the heat shock response represent a promising new direction for the treatment of prostate cancer. Herein, the development of a C-terminal Hsp90 inhibitor, KU174, is described, which demonstrates anti-cancer activity in prostate cancer cells in the absence of a HSR and describe a novel approach to characterize Hsp90 inhibition in cancer cells. METHODS: PC3-MM2 and LNCaP-LN3 cells were used in both direct and indirect in vitro Hsp90 inhibition assays (DARTS, Surface Plasmon Resonance, co-immunoprecipitation, luciferase, Western blot, anti-proliferative, cytotoxicity and size exclusion chromatography) to characterize the effects of KU174 in prostate cancer cells. Pilot in vivo efficacy studies were also conducted with KU174 in PC3-MM2 xenograft studies. RESULTS: KU174 exhibits robust anti-proliferative and cytotoxic activity along with client protein degradation and disruption of Hsp90 native complexes without induction of a HSR. Furthermore, KU174 demonstrates direct binding to the Hsp90 protein and Hsp90 complexes in cancer cells. In addition, in pilot in-vivo proof-of-concept studies KU174 demonstrates efficacy at 75 mg/kg in a PC3-MM2 rat tumor model. CONCLUSIONS: Overall, these findings suggest C-terminal Hsp90 inhibitors have potential as therapeutic agents for the treatment of prostate cancer.
Assuntos
Antineoplásicos/uso terapêutico , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Proteínas de Neoplasias/antagonistas & inibidores , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo , Animais , Western Blotting , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Inibidores do Crescimento/farmacologia , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Masculino , Proteínas de Neoplasias/metabolismo , Novobiocina/farmacologia , Ligação Proteica/efeitos dos fármacos , RatosRESUMO
PURPOSE: Hsp90 is important in the folding, maturation and stabilization of pro-tumorigenic client proteins and represents a viable drug target for the design of chemotherapies. Previously, we reported the development of novobiocin analogues designed to inhibit the C-terminal portion of Hsp90, which demonstrated the ability to decrease client protein expression. We now report the characterization of the novel novobiocin analogue, F-4, which demonstrates improved cytotoxicity in prostate cancer cell lines compared to the N-terminal inhibitor, 17-AAG. MATERIALS AND METHODS: LNCaP and PC-3 cells were treated with 17-AAG or F-4 in anti-proliferative, apoptosis, cell cycle and cytotoxicity assays. Western blot and prostate specific antigen (PSA) ELISAs were used to determine client protein degradation, induction of Hsp90 and to assess the functional status of the androgen receptor (AR) in response to F-4 treatment. Surface plasmon resonance (SPR) was also used to determine the binding properties of F-4 to Hsp90. RESULTS: F-4 demonstrated improved potency and efficacy compared to novobiocin in anti-proliferative assays and decreased expression of client proteins. PSA secretion was inhibited in a dose-dependent manner that paralleled a decrease in AR expression. The binding of F-4 to Hsp90 was determined to be saturable with a binding affinity (K(d)) of 100 microM. In addition, superior efficacy was demonstrated by F-4 compared to 17-AAG in experiments measuring cytotoxicity and apoptosis. CONCLUSIONS: These data reveal distinct modes of action for N-terminal and C-terminal Hsp90 inhibitors, which may offer unique therapeutic benefits for the treatment of prostate cancer.
Assuntos
Sistemas de Liberação de Medicamentos , Inibidores do Crescimento/farmacologia , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Novobiocina/análogos & derivados , Novobiocina/farmacologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Masculino , Neoplasias da Próstata/patologia , SpodopteraRESUMO
Heat shock protein 90 (Hsp90) is a molecular chaperone involved in the trafficking of proteins in the cell. Under stressful conditions, Hsp90 stabilizes its client proteins and provides protection to the cell against cellular stressors such as in cancer cells. Disruption of Hsp90 leads to client protein degradation and often cell death. As Hsp90 has been found to be either overexpressed or constitutively more active in cancer cells, inhibitors of Hsp90 may have cancer cell selectivity. The N-terminal inhibitors, geldanamycin and radiciol, were the first two described inhibitors of Hsp90, but were not clinically useful. Subsequent analogues-17 allylamino-17demethoxygeldanamycin and 17 dimethylaminoethylamino-17-demethoxygeldanamycin-were found to be more clinically appropriate and have been studied in a number of clinical trials since 1999. In addition, to the N-terminal site of Hsp90, the C-terminal site appears to be another target for inhibition of Hsp90. More recently, inhibitors of the C terminus of Hsp90 have been developed and studied in vitro with promising results.
Assuntos
Antineoplásicos/uso terapêutico , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Ensaios Clínicos como Assunto , HumanosRESUMO
The 90-kDa heat shock protein (Hsp90) assists in the proper folding of numerous mutated or overexpressed signal transduction proteins that are involved in cancer. Consequently, there is considerable interest in developing chemotherapeutic drugs that specifically disrupt the function of Hsp90. Here, we investigated the extent to which a novel novobiocin-derived C-terminal Hsp90 inhibitor, designated KU135, induced antiproliferative effects in Jurkat T-lymphocytes. The results indicated that KU135 bound directly to Hsp90, caused the degradation of known Hsp90 client proteins, and induced more potent antiproliferative effects than the established N-terminal Hsp90 inhibitor 17-allylamino-demethoxygeldanamycin (17-AAG). Closer examination of the cellular response to KU135 and 17-AAG revealed that only 17-AAG induced a strong up-regulation of Hsp70 and Hsp90. In addition, KU135 caused wild-type cells to undergo G(2)/M arrest, whereas cells treated with 17-AAG accumulated in G(1). Furthermore, KU135 but not 17-AAG was found to be a potent inducer of mitochondria-mediated apoptosis as evidenced, in part, by the fact that cell death was inhibited to a similar extent by Bcl-2/Bcl-x(L) overexpression or the depletion of apoptotic protease-activating factor-1 (Apaf-1). Together, these data suggest that KU135 inhibits cell proliferation by regulating signaling pathways that are mechanistically different from those targeted by 17-AAG and as such represents a novel opportunity for Hsp90 inhibition.
Assuntos
Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Novobiocina/análogos & derivados , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Western Blotting , Ciclo Celular/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Cromatografia de Afinidade , Citometria de Fluxo , Humanos , Células Jurkat , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Novobiocina/metabolismo , Novobiocina/farmacologia , Ressonância de Plasmônio de SuperfícieRESUMO
Novobiocin, a known DNA gyrase inhibitor, binds to a nucleotide-binding site located on the Hsp90 C-terminus and induces degradation of Hsp90-dependent client proteins at approximately 700 microM in breast cancer cells (SKBr3). Although many analogues of novobiocin have been synthesized, it was only recently demonstrated that monomeric species exhibit antiproliferative activity against various cancer cell lines. To further refine the essential elements of the coumarin core, a series of modified coumarin derivatives was synthesized and evaluated to elucidate structure-activity relationships for novobiocin as an anticancer agent. Results obtained from these studies have produced novobiocin analogues that manifest low micromolar activity against several cancer cell lines.
Assuntos
Cumarínicos/química , Desenho de Fármacos , Novobiocina/síntese química , Novobiocina/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Naftalenos/química , Novobiocina/química , Quinolinas/químicaRESUMO
N-Acyl O-amino phenol derivatives of CBI-TMI and CBI-indole2 are reported as prototypical members of a new class of reductively activated prodrugs of the duocarmycin and CC-1065 class of antitumor agents. The expectation being that hypoxic tumor environments, with their higher reducing capacity, carry an intrinsic higher concentration of "reducing" nucleophiles (e.g., thiols) capable of activating such derivatives (tunable N-O bond cleavage) and increasing their sensitivity to the prodrug treatment. Preliminary studies indicate the prodrugs effectively release the free drug in functional cellular assays for cytotoxic activity approaching or matching the activity of the free drug, yet remain essentially stable and unreactive to in vitro DNA alkylation conditions (<0.1-0.01% free drug release) and pH 7.0 phosphate buffer, and exhibit a robust half-life in human plasma (t1/2 = 3 h). Characterization of a representative O-(acylamino) prodrug in vivo indicates that they approach the potency and exceed the efficacy of the free drug itself (CBI-indole2), indicating that not only is the free drug effectively released from the inactive prodrug but also that they offer additional advantages related to a controlled or targeted release in vivo.
Assuntos
Antibióticos Antineoplásicos/farmacologia , Indóis/farmacologia , Pró-Fármacos/farmacologia , Alquilação/efeitos dos fármacos , Animais , Antibióticos Antineoplásicos/química , Linhagem Celular Tumoral , DNA/efeitos dos fármacos , DNA/metabolismo , Duocarmicinas , Humanos , Indóis/química , Concentração Inibidora 50 , Leucemia L1210/tratamento farmacológico , Camundongos , Camundongos Endogâmicos DBA , Fenóis/química , Fenóis/farmacologiaRESUMO
Human Hsp90 isoforms are molecular chaperones that are often up-regulated in malignances and represent a primary target for Hsp90 inhibitors undergoing clinical evaluation. Hsp90α is a stress-inducible isoform of Hsp90 that plays a significant role in apoptosis and metastasis. Though Hsp90α is secreted into the extracellular space under metastatic conditions, its role in cancer biology is poorly understood. We report that Hsp90α associates with the Aha1 co-chaperone and found this complex to localize in secretory vesicles and at the leading edge of migrating cells. Knockdown of Hsp90α resulted in a defect in cell migration. The functional role of Hsp90α/Aha1 was studied by treating the cells with various novobiocin-based Hsp90 C-terminal inhibitors. These inhibitors disrupted the Hsp90α/Aha1 complex, caused a cytoplasmic redistribution of Hsp90α and Aha1, and decreased cell migration. Structure-function studies determined that disruption of Hsp90α/Aha1 association and inhibition of cell migration correlated with the presence of a benzamide side chain, since an acetamide substituted analog was less effective. Our results show that disruption of Hsp90α/Aha1 interactions with novobiocin-based Hsp90 C-terminal inhibitors may limit the metastatic potential of tumors.
Assuntos
Movimento Celular/efeitos dos fármacos , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Chaperonas Moleculares/metabolismo , Novobiocina/farmacologia , Linhagem Celular , Regulação da Expressão Gênica , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Humanos , Chaperonas Moleculares/genética , Ligação Proteica , Dobramento de Proteína , Isoformas de ProteínasRESUMO
Tumorigenicity studies often employ outbred nude mice, in the absence of direct evidence that this mixed genetic background will negatively affect experimental outcome. Here we show that outbred nude mice carry two different alleles of Pla2g2a, a genetic modifier of intestinal tumorigenesis in mice. Here, we identify previous unreported linked polymorphisms in the promoter, noncoding and coding sequences of Pla2g2a and show that outbred nude mice from different commercial providers are heterogeneous for this polymorphic Pla2g2a allele. This heterogeneity even extends to mice obtained from a single commercial provider, which display mixed Pla2g2a genotypes. Notably, we demonstrated that the polymorphic Pla2g2a allele affects orthotopic xenograft establishment of human colon cancer cells in outbred nude mice. This finding establishes a non-cell-autonomous role for Pla2g2a in suppressing intestinal tumorigenesis. Using in vitro reporter assays and pharmacological inhibitors, we show promoter polymorphisms and nonsense-mediated RNA decay (NMD) as underlying mechanisms that lead to low Pla2g2a mRNA levels in tumor-sensitive mice. Together, this study provides mechanistic insight regarding Pla2g2a polymorphisms and demonstrates a non-cell-autonomous role for Pla2g2a in suppressing tumors. Moreover, our direct demonstration that mixed genetic backgrounds of outbred nude mice can significantly affect baseline tumorigenicity cautions against future use of outbred mice for tumor xenograft studies.
Assuntos
Carcinogênese/genética , Fosfolipases A2 do Grupo II/genética , Polimorfismo Genético , Ensaios Antitumorais Modelo de Xenoenxerto/métodos , Alelos , Animais , Clonagem Molecular , Genótipo , Fosfolipases A2 do Grupo II/metabolismo , Células HCT116 , Humanos , Intestinos/patologia , Camundongos , Camundongos Nus , Degradação do RNAm Mediada por Códon sem Sentido , Plasmídeos/genética , Regiões Promotoras Genéticas , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
Hsp90 C-terminal inhibitors are advantageous for the development of new cancer chemotherapeutics due to their ability to segregate client protein degradation from induction of the prosurvival heat shock response, which is a major detriment associated with Hsp90 N-terminal inhibitors under clinical investigation. Based upon prior SAR trends, a 1,2,3-triazole side chain was placed in lieu of the aryl side chain and attached to both the coumarin and biphenyl scaffold. Antiproliferative studies against SKBr3 and MCF-7 breast cancer cell lines demonstrated these triazole-containing compounds to exhibit improved activity. These compounds were shown to manifest Hsp90 inhibitory activity through Western blot analysis and represent a new scaffold upon which more potent inhibitors can be pursued.
RESUMO
Osteosarcoma (OS) is a bone malignancy that affects children and adolescents. It is a highly aggressive tumor and typically metastasizes to lungs. Despite aggressive chemotherapy and surgical treatments, the current 5 year survival rate is 60-70%. Clinically relevant models are needed to understand OS pathobiology, metastatic progression from bones to lungs, and ultimately, to develop more efficacious treatment strategies and improve survival rates in OS patients with metastasis. The main goal of this study was to develop and characterize an in vivo OS model that will allow non-invasive tracking of tumor progression in real time, and aid in studying OS pathobiology, and screening of potential therapeutic agents against OS. In this study, we have used a multi-modality approach using bioluminescent imaging, electron microscopy, micro-computed tomography, and histopathology to develop and characterize a preclinical Bioluminescent Osteosarcoma Orthotopic Mouse (BOOM) model, using 143B human OS cell line. The results of this study clearly demonstrate that the BOOM model represents the clinical disease as evidenced by a spectrum of changes associated with tumor establishment, progression and metastasis, and detection of known OS biomarkers in the primary and metastatic tumor tissue. Key novel findings of this study include: (a) multimodality approach for extensive characterization of the BOOM model using 143B human OS cell line; (b) evidence of renal metastasis in OS orthotopic model using 143B cells; (c) evidence of Runx2 expression in the metastatic lung tissue; and (d) evidence of the presence of extracellular membrane vesicles and myofibroblasts in the BOOM model.
RESUMO
In treating cancer with clinically approved chemotherapies, the high systemic toxicity and lack of selectivity for malignant cells often result in an overall poor response rate. One pharmacological approach to improve patient response is to design targeted therapies that exploit the cancer milieu by reductively activating prodrugs, which results in the selective release of the free drug in the tumor tissue. Previously, we characterized prodrugs of seco-CBI-indole 2 (CBI-indole 2) designed to be activated in hypoxic tumor microenvironments, wherein the tumor maintains higher concentrations of "reducing" nucleophiles capable of preferentially releasing the free drug by nucleophilic attack on a weak N-O bond. Of these prodrugs, BocNHO-CBI-indole 2 (BocNHO) surpassed the efficacy of the free drug, CBI-indole 2, when examined in vivo in the murine L1210 leukemia model and demonstrated reduced toxicity suggesting a targeted or sustained release in vivo. Herein, we further examine the biological activity of the BocNHO prodrug in murine breast cancer, as well as human prostate and lung cancer cell lines, in vitro. Notably, BocNHO manifests potent antiproliferative and cytotoxic activity in all three tumor cell lines. However, in comparison to the activity observed in the murine cancer cell line, the human cancer cell lines were less sensitive, especially at early timepoints for cytotoxicity. Based on these findings, BocNHO was tested in a more clinically relevant orthotopic lung tumor model, revealing significant efficacy and reduced toxicity compared with the free drug. The data suggests that this pharmacological approach to designing targeted therapies is amenable to human solid tumors.
Assuntos
Antineoplásicos/farmacologia , Carbamatos/farmacologia , Indóis/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Pró-Fármacos/farmacologia , Animais , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Carbamatos/uso terapêutico , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Indóis/uso terapêutico , Camundongos , Camundongos Nus , Oxirredução , Pró-Fármacos/uso terapêutico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Two novel cyclic N-acyl O-amino phenol prodrugs are reported as new members of a unique class of reductively cleaved prodrugs of the duocarmycin family of natural products. These prodrugs were explored with the expectation that they may be cleaved selectively within hypoxic tumor environments that have intrinsically higher concentrations of reducing nucleophiles and were designed to liberate the free drug without the release of an extraneous group. In vivo evaluation of the prodrug 6 showed that it exhibits extraordinary efficacy (T/C > 1500, L1210; 6/10 one year survivors), substantially exceeding that of the free drug, that its therapeutic window of activity is much larger, permitting a dosing ≥ 40-fold higher than the free drug, and yet that it displays a potency in vivo that approaches the free drug (within 3-fold). Clearly, the prodrug 6 benefits from either its controlled slow release of the free drug or its preferential intracellular reductive cleavage.
Assuntos
Antibióticos Antineoplásicos/administração & dosagem , Indóis/administração & dosagem , Pró-Fármacos , Alquilação , Animais , Antibióticos Antineoplásicos/química , Hipóxia Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Química Farmacêutica , Cromatografia Líquida de Alta Pressão , DNA/química , Preparações de Ação Retardada , Duocarmicinas , Indicadores e Reagentes , Indóis/química , Leucemia L1210/tratamento farmacológico , Camundongos , Pirrolidinonas/administração & dosagem , Pirrolidinonas/química , Espectrofotometria Ultravioleta , Estereoisomerismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The 90 kDa heat-shock protein (Hsp90) and other cochaperones allow for proper folding of nascent or misfolded polypeptides. Cancer cells exploit these chaperones by maintaining the stability of mutated and misfolded oncoproteins and allowing them to evade proteosomal degradation. Inhibiting Hsp90 is an attractive strategy for cancer therapy, as the concomitant degradation of multiple oncoproteins may lead to effective anti-neoplastic agents. Unfortunately, early clinical trials have been disappointing with N-terminal Hsp90 inhibitors, as it is unclear whether the problems that plague current Hsp90 inhibitors in clinical trials are related to on-target or off-target activity. One approach to overcome these pitfalls is to identify structurally diverse scaffolds that improve Hsp90 inhibitory activity in the cancer cell milieu. Utilizing a panel of cancer cell lines that express luciferase, we have designed an in-cell Hsp90-dependent luciferase refolding assay. The assay was optimized using previously identified Hsp90 inhibitors and experimental novobiocin analogues against prostate, colon, and lung cancer cell lines. This assay exhibits good interplate precision (% CV), a signal-to-noise ratio (S/N) of ≥7, and an approximate Z-factor ranging from 0.5 to 0.7. Novobiocin analogues that revealed activity in this assay were examined via western blot experiments for client protein degradation, a hallmark of Hsp90 inhibition. Subsequently, a pilot screen was conducted using the Prestwick library, and two compounds, biperiden and ethoxyquin, revealed significant activity. Here, we report the development of an in-cell Hsp90-dependent luciferase refolding assay that is amenable across cancer cell lines for the screening of inhibitors in their specific milieu.
Assuntos
Antineoplásicos/farmacologia , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Ensaios de Triagem em Larga Escala/métodos , Luciferases/química , Redobramento de Proteína/efeitos dos fármacos , Animais , Bioensaio , Western Blotting , Linhagem Celular Tumoral , Corantes , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Humanos , Luciferases/antagonistas & inibidores , Novobiocina/análogos & derivados , Novobiocina/farmacologia , Desnaturação Proteica , Coelhos , Reticulócitos/efeitos dos fármacos , Reticulócitos/metabolismo , Rodaminas , Bibliotecas de Moléculas PequenasRESUMO
A unique heterocyclic carbamate prodrug of seco-CBI-indole(2) that releases no residual byproduct is reported as a new member of a class of hydrolyzable prodrugs of the duocarmycin and CC-1065 family of natural products. The prodrug was designed to be activated by hydrolysis of a carbamate releasing the free drug without the cleavage release of a traceable extraneous group. Unlike prior carbamate prodrugs examined that are rapidly cleaved in vivo, the cyclic carbamate was found to be exceptionally stable to hydrolysis under both chemical and biological conditions providing a slow, sustained release of the exceptionally potent free drug. An in vivo evaluation of the prodrug found that its efficacy exceeded that of the parent drug, that its therapeutic window of efficacy versus toxicity is much larger than the parent drug, and that its slow free drug release permitted the safe and efficacious use of doses 150-fold higher than the parent compound.
Assuntos
Antineoplásicos/metabolismo , Carbamatos/química , Desenho de Fármacos , Indóis/metabolismo , Pró-Fármacos/metabolismo , Pró-Fármacos/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Ciclopropanos/química , Duocarmicinas , Humanos , Hidrólise , Indóis/química , Indóis/farmacologia , Concentração Inibidora 50 , Camundongos , Pirrolidinonas/química , Pirrolidinonas/metabolismo , Pirrolidinonas/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The design, synthesis, and biological evaluation of conformationally constrained coumermycin A1 analogues are reported. Compounds were evaluated against both breast cancer (SKBr3 and MCF7) and prostate cancer (PC3 mm2, A549, and HT29) cell lines. Non-noviosylated coumermycin A1 analogues that manifest potent antiproliferative activity resulting from Hsp90 inhibition are provided, wherein replacement of the stereochemically complex noviose sugar with readily available piperidine rings resulted in â¼100 fold increase in antiproliferative activities as compared to coumermycin A1, producing small molecule Hsp90 inhibitors that exhibit nanomolar activities.