RESUMO
BACKGROUND: OX40 has been widely studied as a target for immunotherapy with agonist antibodies taken forward into clinical trials for cancer where they are yet to show substantial efficacy. Here, we investigated potential mechanisms of action of anti-mouse (m) OX40 and anti-human (h) OX40 antibodies, including a clinically relevant monoclonal antibody (mAb) (GSK3174998) and evaluated how isotype can alter those mechanisms with the aim to develop improved antibodies for use in rational combination treatments for cancer. METHODS: Anti-mOX40 and anti-hOX40 mAbs were evaluated in a number of in vivo models, including an OT-I adoptive transfer immunization model in hOX40 knock-in (KI) mice and syngeneic tumor models. The impact of FcγR engagement was evaluated in hOX40 KI mice deficient for Fc gamma receptors (FcγR). Additionally, combination studies using anti-mouse programmed cell death protein-1 (mPD-1) were assessed. In vitro experiments using peripheral blood mononuclear cells (PBMCs) examining possible anti-hOX40 mAb mechanisms of action were also performed. RESULTS: Isotype variants of the clinically relevant mAb GSK3174998 showed immunomodulatory effects that differed in mechanism; mIgG1 mediated direct T-cell agonism while mIgG2a acted indirectly, likely through depletion of regulatory T cells (Tregs) via activating FcγRs. In both the OT-I and EG.7-OVA models, hIgG1 was the most effective human isotype, capable of acting both directly and through Treg depletion. The anti-hOX40 hIgG1 synergized with anti-mPD-1 to improve therapeutic outcomes in the EG.7-OVA model. Finally, in vitro assays with human peripheral blood mononuclear cells (hPBMCs), anti-hOX40 hIgG1 also showed the potential for T-cell stimulation and Treg depletion. CONCLUSIONS: These findings underline the importance of understanding the role of isotype in the mechanism of action of therapeutic mAbs. As an hIgG1, the anti-hOX40 mAb can elicit multiple mechanisms of action that could aid or hinder therapeutic outcomes, dependent on the microenvironment. This should be considered when designing potential combinatorial partners and their FcγR requirements to achieve maximal benefit and improvement of patient outcomes.
Assuntos
Receptores OX40 , Animais , Humanos , Camundongos , Receptores OX40/agonistas , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Linhagem Celular Tumoral , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/efeitos dos fármacos , Modelos Animais de DoençasRESUMO
BACKGROUND: The phase I first-in-human study ENGAGE-1 evaluated the humanized IgG1 OX40 agonistic monoclonal antibody GSK3174998 alone (Part 1 (P1)) or in combination with pembrolizumab (Part 2 (P2)) in patients with advanced solid tumors. METHODS: GSK3174998 (0.003-10 mg/kg) ± pembrolizumab (200 mg) was administered intravenously every 3 weeks using a continuous reassessment method for dose escalation. Primary objectives were safety and tolerability; secondary objectives included pharmacokinetics, immunogenicity, pharmacodynamics, and clinical activity. RESULTS: 138 patients were enrolled (45 (P1) and 96 (P2, including 3 crossovers)). Treatment-related adverse events occurred in 51% (P1) and 64% (P2) of patients, fatigue being the most common (11% and 24%, respectively). No dose-toxicity relationship was observed, and maximum-tolerated dose was not reached. Dose-limiting toxicities (P2) included Grade 3 (G3) pleural effusion and G1 myocarditis with G3 increased troponin. GSK3174998 ≥0.3 mg/kg demonstrated pharmacokinetic linearity and >80% receptor occupancy on circulating T cells; 0.3 mg/kg was selected for further evaluation. Limited clinical activity was observed for GSK3174998 (P1: disease control rate (DCR) ≥24 weeks 9%) and was not greater than that expected for pembrolizumab alone (P2: overall response rate 8%, DCR ≥24 weeks 28%). Multiplexed immunofluorescence data from paired biopsies suggested that increased infiltration of natural killer (NK)/natural killer T (NKT) cells and decreased regulatory T cells (Tregs) in the tumor microenvironment may contribute to clinical responses: CD16+CD56-CD134+ NK /NKT cells and CD3+CD4+FOXP3+CD134+ Tregs exhibited the largest magnitude of change on treatment, whereas CD3+CD8+granzyme B+PD-1+CD134+ cytotoxic T cells were the least variable. Tumor gene expression profiling revealed an upregulation of inflammatory responses, T-cell proliferation, and NK cell function on treatment with some inflammatory cytokines upregulated in peripheral blood. However, target engagement, evidenced by pharmacologic activity in peripheral blood and tumor tissue, did not correlate with clinical efficacy. The low number of responses precluded identifying a robust biomarker signature predictive of response. CONCLUSIONS: GSK3174998±pembrolizumab was well tolerated over the dose range tested and demonstrated target engagement. Limited clinical activity does not support further development of GSK3174998±pembrolizumab in advanced cancers. TRIAL REGISTRATION NUMBER: NCT02528357.
Assuntos
Antineoplásicos , Neoplasias , Humanos , Neoplasias/patologia , Anticorpos Monoclonais Humanizados/efeitos adversos , Antineoplásicos/uso terapêutico , Anticorpos Monoclonais/uso terapêutico , Microambiente TumoralRESUMO
INTRODUCTION: Currently, triple-negative breast cancer (TNBC) has limited therapeutic options beyond chemotherapy and has worse outcomes than other breast cancer subtypes. Initial experience with immune checkpoint blockade for the treatment of TNBC has indicated that modifying the tumor immune response represents a promising direction of investigation. Subsequent studies have led to a deeper understanding of the heterogeneity of this disease and have informed further exploration of numerous potential therapeutic approaches to intervene in the tumor microenvironment (TME). AREAS COVERED: Initial work in this arena has focused on enhanced definition of checkpoints in activation of an adaptive immune response. In this review, we discuss recent efforts that have looked into components of innate immunity to reverse immunosuppressive phenotypes and augment antitumor immune response. EXPERT OPINION: Current treatment options for TNBC have been improved with the approval of immune checkpoint inhibitors (ICI) in both advanced and early-stage disease; however, the challenge remains to expand the number of patients that will benefit from immunotherapy. Optimizing the innate immune response represents an opportunity to improve this therapeutic index, and the development of an array of novel agents is underway. Success will depend on precision characterization of the patient TME and selection of ideal combination therapy.
Assuntos
Neoplasias de Mama Triplo Negativas , Biomarcadores Tumorais/genética , Humanos , Imunidade Inata , Imunoterapia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/patologia , Microambiente TumoralRESUMO
A major contributing factor to the high mortality rate associated with acute myeloid leukemia and multiple myeloma is the development of resistance to chemotherapy. We have shown that the combination of tipifarnib, a nonpeptidomimetic farnesyltransferase inhibitor (FTI), with bortezomib, a proteosome inhibitor, promotes synergistic death and overcomes de novo drug resistance in acute myeloid leukemia cell lines. Experiments were undertaken to identify the molecular mechanisms by which tipifarnib produces cell death in acute myeloid leukemia and multiple myeloma cell lines (U937 and 8226, respectively). Tipifarnib, but not other FTIs tested [N-[4-[2(R)-amino-3-mercaptopropyl]amino-2-phenylbenzoyl]methionine methyl ester trifluoroacetate salt (FTI-277) and 2'-methyl-5-((((1-trityl-1H-imidazol-4-yl)methyl)amino)methyl)-[1,1'-biphenyl]-2-carboxylic acid (FTI-2153), promotes elevations in intracellular free-calcium concentrations ([Ca(2+)](i)) in both cell lines. These elevations in [Ca(2+)](i) were accompanied by highly dynamic plasmalemmal blebbing and frequently resulted in membrane lysis. The tipifarnib-induced elevations in [Ca(2+)](i) were not blocked by thapsigargin or ruthenium red, but were inhibited by application of Ca(2+)-free extracellular solution and by the Ca(2+) channel blockers Gd(3+) and La(3+). Conversely, 2-aminoethoxydiphenyl borate (2-APB) potentiated the tipifarnib-evoked [Ca(2+)](i) overload. Preventing Ca(2+) influx diminished tipifarnib-evoked cell death, whereas 2-APB potentiated this effect, demonstrating a link between tipifarnib-induced Ca(2+) influx and apoptosis. These data suggest that tipifarnib exerts its effects by acting on a membrane channel with pharmacological properties consistent with store-operated channels containing the Orai3 subunit. It is noteworthy that Orai3 transcripts were found to be expressed at lower levels in tipifarnib-resistant 8226/R5 cells. Our results indicate tipifarnib causes cell death via a novel mechanism involving activation of a plasma membrane Ca(2+) channel and intracellular Ca(2+) overload.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Canais de Cálcio/metabolismo , Cálcio/metabolismo , Membrana Celular/metabolismo , Farnesiltranstransferase/antagonistas & inibidores , Quinolonas/farmacologia , Membrana Celular/efeitos dos fármacos , Retículo Endoplasmático/efeitos dos fármacos , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/metabolismo , Células Tumorais Cultivadas , Células U937RESUMO
B-cell maturation antigen (BCMA) is an attractive therapeutic target highly expressed on differentiated plasma cells in multiple myeloma and other B-cell malignancies. GSK2857916 (belantamab mafodotin, BLENREP) is a BCMA-targeting antibody-drug conjugate approved for the treatment of relapsed/refractory multiple myeloma. We report that GSK2857916 induces immunogenic cell death in BCMA-expressing cancer cells and promotes dendritic cell activation in vitro and in vivo GSK2857916 treatment enhances intratumor immune cell infiltration and activation, delays tumor growth, and promotes durable complete regressions in immune-competent mice bearing EL4 lymphoma tumors expressing human BCMA (EL4-hBCMA). Responding mice are immune to rechallenge with EL4 parental and EL4-hBCMA cells, suggesting engagement of an adaptive immune response, immunologic memory, and tumor antigen spreading, which are abrogated upon depletion of endogenous CD8+ T cells. Combinations with OX40/OX86, an immune agonist antibody, significantly enhance antitumor activity and increase durable complete responses, providing a strong rationale for clinical evaluation of GSK2857916 combinations with immunotherapies targeting adaptive immune responses, including T-cell-directed checkpoint modulators.
Assuntos
Anticorpos Monoclonais Humanizados/farmacologia , Antígeno de Maturação de Linfócitos B/antagonistas & inibidores , Linfócitos T CD8-Positivos/imunologia , Imunoconjugados/farmacologia , Morte Celular Imunogênica , Linfoma/tratamento farmacológico , Mieloma Múltiplo/tratamento farmacológico , Animais , Anticorpos Monoclonais/química , Apoptose , Antígeno de Maturação de Linfócitos B/imunologia , Proliferação de Células , Feminino , Humanos , Linfoma/imunologia , Linfoma/metabolismo , Linfoma/patologia , Camundongos , Camundongos Endogâmicos C57BL , Mieloma Múltiplo/imunologia , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
INTRODUCTION: OX-40 co-stimulatory signaling plays a role in mounting anti-tumor immune responses and clinical trials targeting this pathway are ongoing. However, the association of with OX-40 protein expression with clinical outcomes and pathological features in non-small cell lung cancer (NSCLC) are largely unknown. METHODS: Surgically-resected stage I-III NSCLC specimens (N = 100) were stained by immunohistochemistry (IHC) for the following immune markers: OX-40, PD-L1, PD-1, CD3, CD4, CD8, CD45RO, CD57, CD68, FOXP3, granzyme B, and ICOS. Immune-related markers mRNA expression were also assessed. We evaluated the association of OX-40 levels with major clinicopathologic variables, including molecular driver mutations. RESULTS: OX-40 IHC expression was observed in all tested tumors, predominantly localized in the membrane of the tumor immune infiltrate, and was not associated with a specific clinicopathologic or molecular subtype. High OX-40 expression levels measured by IHC median score were associated with better overall survival (OS) (p = 0.002), independent of CD3/CD8, PD-L1, and ICOS expression. High OX-40 IHC score was associated with increased expression of immune-related genes such as CD3, IFN-gamma, ICOS, CD8, CXCL9, CXCL10, CCL5, granzyme K. CONCLUSIONS: High OX-40 IHC expression in the tumor immune infiltrate is associated with favorable prognosis and increased levels of immune-related genes including IFN-gamma in patients with surgically resected stage I-III NSCLC. Its prognostic utility is independent of PD-L1 and other common markers of immune activation. High OX-40 expression potentially identifies a unique subgroup of NSCLC that may benefit from co-stimulation with OX-40 agonist antibodies and potentially enhance the efficacy of existing immune checkpoint therapies.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Expressão Gênica , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/mortalidade , Linfócitos do Interstício Tumoral/metabolismo , Receptores OX40/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos Imunológicos/farmacologia , Biomarcadores , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Feminino , Humanos , Imuno-Histoquímica , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Linfócitos do Interstício Tumoral/imunologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Receptores OX40/metabolismo , Microambiente TumoralRESUMO
PURPOSE: OX40 agonist-based combinations are emerging as a novel avenue to improve the effectiveness of cancer immunotherapy. To better guide its clinical development, we characterized the role of the OX40 pathway in tumor-reactive immune cells. We also evaluated combining OX40 agonists with targeted therapy to combat resistance to cancer immunotherapy.Experimental Design: We utilized patient-derived tumor-infiltrating lymphocytes (TILs) and multiple preclinical models to determine the direct effect of anti-OX40 agonistic antibodies on tumor-reactive CD8+ T cells. We also evaluated the antitumor activity of an anti-OX40 antibody plus PI3Kß inhibition in a transgenic murine melanoma model (Braf mutant, PTEN null), which spontaneously develops immunotherapy-resistant melanomas. RESULTS: We observed elevated expression of OX40 in tumor-reactive CD8+ TILs upon encountering tumors; activation of OX40 signaling enhanced their cytotoxic function. OX40 agonist antibody improved the antitumor activity of CD8+ T cells and the generation of tumor-specific T-cell memory in vivo. Furthermore, combining anti-OX40 with GSK2636771, a PI3Kß-selective inhibitor, delayed tumor growth and extended the survival of mice with PTEN-null melanomas. This combination treatment did not increase the number of TILs, but it instead significantly enhanced proliferation of CD8+ TILs and elevated the serum levels of CCL4, CXCL10, and IFNγ, which are mainly produced by memory and/or effector T cells. CONCLUSIONS: These results highlight a critical role of OX40 activation in potentiating the effector function of tumor-reactive CD8+ T cells and suggest further evaluation of OX40 agonist-based combinations in patients with immune-resistant tumors.
Assuntos
Anticorpos Anti-Idiotípicos/farmacologia , Melanoma/tratamento farmacológico , PTEN Fosfo-Hidrolase/genética , Receptores OX40/imunologia , Animais , Antígenos de Diferenciação/genética , Antígenos de Diferenciação/farmacologia , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/imunologia , Linhagem Celular Tumoral , Feminino , Xenoenxertos , Humanos , Imunoterapia , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Linfócitos do Interstício Tumoral/imunologia , Melanoma/genética , Melanoma/metabolismo , Melanoma/patologia , Camundongos , Receptores OX40/antagonistas & inibidoresRESUMO
Purpose: Radiation is used extensively to treat localized cancer, but improved understanding of its effects on the immune system has increased interest in its potential systemic (abscopal) effects, particularly in combination with checkpoint inhibitors such as anti-PD1. The majority of patients either do not respond or develop resistance to monotherapy over time. Here, we investigated the efficacy of OX40 (CD134) stimulation as an alternative immunotherapeutic approach in combination with radiotherapy (XRT) in a murine model of anti-PD1-resistant lung tumors.Experimental Design: We established a bilateral tumor model in 129Sv/Ev mice using an anti-PD1-resistant lung tumor cell line. Primary tumors were treated with intratumoral injection of an OX40 agonist antibody, given as adjuvant therapy after XRT (36 Gy in three 12-Gy fractions), whereas secondary tumors were left untreated to investigate abscopal outcomes.Results: The combination of XRT followed by OX40 stimulation effectively inhibited local and systemic antitumor growth, limited lung metastases, and improved survival rates. This treatment regimen augmented CD4+ and CD8+ T-cell expansion. XRT induced the expression of OX40 on T cells in tumors and spleens and increased the percentages of splenic CD103+ dendritic cells.Conclusions: Our data extend the benefits of radiation to systemic disease control, especially when combined with anti-OX40 agonist to promote immunologically mediated abscopal effects. Moreover, this study provides a rational treatment approach and sequence to overcome anti-PD1-resistant poorly immunogenic tumors. Clin Cancer Res; 24(22); 5735-43. ©2018 AACR.
Assuntos
Antineoplásicos Imunológicos/farmacologia , Neoplasias Pulmonares/metabolismo , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptores OX40/metabolismo , Animais , Linhagem Celular Tumoral , Quimiorradioterapia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Relação Dose-Resposta à Radiação , Feminino , Humanos , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/terapia , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismo , Linfócitos do Interstício Tumoral/efeitos da radiação , Camundongos , Receptores OX40/antagonistas & inibidores , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Mouse syngeneic tumor models are widely used tools to demonstrate activity of novel anti-cancer immunotherapies. Despite their widespread use, a comprehensive view of their tumor-immune compositions and their relevance to human tumors has only begun to emerge. We propose each model possesses a unique tumor-immune infiltrate profile that can be probed with immunotherapies to inform on anti-tumor mechanisms and treatment strategies in human tumors with similar profiles. In support of this endeavor, we characterized the tumor microenvironment of four commonly used models and demonstrate they encompass a range of immunogenicities, from highly immune infiltrated RENCA tumors to poorly infiltrated B16F10 tumors. Tumor cell lines for each model exhibit different intrinsic factors in vitro that likely influence immune infiltration upon subcutaneous implantation. Similarly, solid tumors in vivo for each model are unique, each enriched in distinct features ranging from pathogen response elements to antigen presentation machinery. As RENCA tumors progress in size, all major T cell populations diminish while myeloid-derived suppressor cells become more enriched, possibly driving immune suppression and tumor progression. In CT26 tumors, CD8 T cells paradoxically increase in density yet are restrained as tumor volume increases. Finally, immunotherapy treatment across these different tumor-immune landscapes segregate into responders and non-responders based on features partially dependent on pre-existing immune infiltrates. Overall, these studies provide an important resource to enhance our translation of syngeneic models to human tumors. Future mechanistic studies paired with this resource will help identify responsive patient populations and improve strategies where immunotherapies are predicted to be ineffective.
Assuntos
Neoplasias/imunologia , Neoplasias/terapia , Microambiente Tumoral , Animais , Complexo CD3/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Quimiocinas/metabolismo , Proteínas do Sistema Complemento/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Imunoterapia , Antígeno Ki-67/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Células Mieloides/patologia , Invasividade Neoplásica , Neoplasias/genética , Neoplasias/patologia , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , Resultado do TratamentoRESUMO
It has been established in preclinical models of multiple myeloma and acute myeloid leukemia (AML) that the bone marrow microenvironment provides protection from chemotherapy- and death receptor-mediated apoptosis. This form of resistance, termed de novo drug resistance, occurs independent of chronic exposure to cancer-related therapies and likely promotes the development of multidrug resistance. Consequently, it is of major interest to identify compounds or drug combinations that can overcome environment-mediated resistance. In this study, we investigated the activity of tipifarnib (Zarnestra, formerly R115777) combined with bortezomib (Velcade, formerly PS-341) in microenvironment models of multiple myeloma and AML. The combination proved to be synergistic in multiple myeloma and AML cell lines treated in suspension culture. Even in tumor cells relatively resistant to tipifarnib, combined activity was maintained. Tipifarnib and bortezomib were also effective when multiple myeloma and AML cells were adhered to fibronectin, providing evidence that the combination overcomes cell adhesion-mediated drug resistance (CAM-DR). Of importance, activation of the endoplasmic reticulum stress response was enhanced and correlated with apoptosis and reversal of CAM-DR. Multiple myeloma and AML cells cocultured with bone marrow stromal cells also remained sensitive, although stromal-adhered tumor cells were partially protected (relative to cells in suspension or fibronectin adhered). Evaluation of the combination using a transwell apparatus revealed that stromal cells produce a protective soluble factor. Investigations are under way to identify the cytokines and/or growth factors involved. In summary, our study provides the preclinical rationale for trials testing the tipifarnib and bortezomib combination in patients with multiple myeloma and AML.
Assuntos
Antineoplásicos/farmacologia , Ácidos Borônicos/farmacologia , Adesão Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos , Leucemia Mieloide Aguda/tratamento farmacológico , Mieloma Múltiplo/tratamento farmacológico , Pirazinas/farmacologia , Quinolonas/farmacologia , Medula Óssea/efeitos dos fármacos , Medula Óssea/metabolismo , Bortezomib , Sinergismo Farmacológico , Quimioterapia Combinada , Fibronectinas/metabolismo , Humanos , Leucemia Mieloide Aguda/metabolismo , Mieloma Múltiplo/metabolismo , Células Estromais/citologia , Células Estromais/efeitos dos fármacos , Células Estromais/metabolismo , Células Tumorais CultivadasRESUMO
We have shown previously that urokinase plasminogen activator receptor (uPAR) and cathepsin B are overexpressed during glioma progression, particularly at the leading edge of the tumor. In the present study, we simultaneously down-regulated uPAR and cathepsin B in SNB19 glioma cell monolayer or SNB19 spheroids using an adenoviral vector carrying antisense uPAR and antisense cathepsin B and a combination of these genes as determined by Western blot analysis. The Ad-uPAR-Cath B-infected cells revealed a marked reduction in tumor growth and invasiveness as compared with the parental and vector controls. In vitro and in vivo angiogenic assays demonstrated inhibition of capillary-like structure formation and microvessel formation after Ad-uPAR-Cath B infection of SNB19 cells when compared with Ad-cytomegalovirus (CMV)-infected or mock-infected controls. Furthermore, using a near infrared fluorescence probe, in vivo imaging for cathepsin B indicated low/undetectable levels of fluorescence after injection of the Ad-uPAR-Cath B construct into pre-established s.c. tumors as compared with Ad-CMV-treated and untreated tumors. The effect with bicistronic construct (Ad-uPAR-Cath B) was much higher than with single (Ad-uPAR/Ad-Cath B) constructs. These results indicate that the down-regulation of cathepsin B and uPAR plays a significant role in inhibiting tumor growth, invasion, and angiogenesis. Hence, the targeting of these two proteases may be a potential therapy for brain tumors and other cancers.
Assuntos
Catepsina B/antagonistas & inibidores , DNA Antissenso/genética , Glioblastoma/genética , Glioblastoma/terapia , Neovascularização Patológica/genética , Neovascularização Patológica/terapia , Receptores de Superfície Celular/antagonistas & inibidores , Adenoviridae/genética , Animais , Catepsina B/genética , Divisão Celular/genética , Movimento Celular/genética , DNA Antissenso/administração & dosagem , Feminino , Terapia Genética/métodos , Glioblastoma/irrigação sanguínea , Glioblastoma/virologia , Humanos , Masculino , Camundongos , Camundongos Nus , Invasividade Neoplásica , Neovascularização Patológica/patologia , Receptores de Superfície Celular/genética , Receptores de Ativador de Plasminogênio Tipo Uroquinase , Esferoides Celulares , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The binding of urokinase plasminogen activator (uPA) to its receptor (uPAR) initiates a proteolytic cascade facilitating the activation of matrix metalloproteinase-9 (MMP-9), which in turn degrades the extracellular matrix. These processes have an established role in tumor invasion and metastasis. Our previous work revealed an inverse association between glioma invasion and the expression of uPAR and MMP-9. In the present study, we used the adenovirus serotype 5 vector system to generate a replication-deficient recombinant adenovirus capable of simultaneously expressing antisense uPAR and antisense MMP-9 (Ad-uPAR-MMP-9). This adenoviral construct is driven by the independent promoter elements cytomegalovirus and bovine growth hormone and SV40 polyadenylation signals to down-regulate key steps in the proteolytic cascade. Ad-uPAR-MMP-9 infection of SNB19 cells significantly decreased uPAR and MMP-9 expression as determined by immunohistochemical and Western blotting analyses. A Matrigel invasion assay revealed marked reduction in the invasiveness of the Ad-uPAR-MMP-9-infected cells compared with parental and vector controls. Tumor spheroids infected with Ad-uPAR-MMP-9 and cocultured with fetal rat brain aggregates did not invade rat brain aggregates, whereas 90-95% of the mock and empty vector-infected cells invaded the rat brain aggregates. Intracranial injection of SNB19 cells infected ex vivo with the Ad-uPAR-MMP-9 antisense bicistronic construct showed decreased invasiveness and tumorigenicity. s.c. injections of the bicistronic antisense construct into established tumors (U87 MG) caused tumor regression. These results support the therapeutic potential of targeting the individual components of the uPAR-MMP-9 by using a single adenovirus construct for the treatment of gliomas and other cancers.
Assuntos
Glioblastoma/genética , Glioblastoma/patologia , Metaloproteinase 9 da Matriz/fisiologia , Receptores de Superfície Celular/fisiologia , Adenoviridae/genética , Animais , Divisão Celular/genética , Movimento Celular/genética , DNA Antissenso/administração & dosagem , DNA Antissenso/genética , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica , Terapia Genética , Glioblastoma/irrigação sanguínea , Glioblastoma/metabolismo , Humanos , Metaloproteinase 9 da Matriz/biossíntese , Metaloproteinase 9 da Matriz/genética , Camundongos , Camundongos Nus , Invasividade Neoplásica , Neovascularização Patológica/genética , Receptores de Superfície Celular/biossíntese , Receptores de Superfície Celular/genética , Receptores de Ativador de Plasminogênio Tipo Uroquinase , Esferoides Celulares , Células Tumorais CultivadasRESUMO
Extracellular proteases have been shown to cooperatively influence matrix degradation and tumor cell invasion through proteolytic cascades, with individual proteases having distinct roles in tumor growth, invasion, migration and angiogenesis. Matrix metalloproteases (MMP)-9 and cathepsin B have been shown to participate in the processes of tumor growth, vascularization and invasion of gliomas. In the present study, we used a cytomegalovirus promoter-driven DNA template approach to induce hairpin RNA (hpRNA)-triggered RNA interference (RNAi) to block MMP-9 and cathepsin B gene expression with a single construct. Transfection of a plasmid vector-expressing double-stranded RNA (dsRNA) for MMP-9 and cathepsin B significantly inhibited MMP-9 and cathepsin B expression and reduced the invasive behavior of SNB19, glioblastoma cell line in Matrigel and spheroid invasion models. Downregulation of MMP-9 and cathepsin B using RNAi in SNB19 cells reduced cell-cell interaction of human microvascular endothelial cells, resulting in the disruption of capillary network formation in both in vitro and in vivo models. Direct intratumoral injections of plasmid DNA expressing hpRNA for MMP-9 and cathepsin B significantly inhibited established glioma tumor growth and invasion in intracranial tumors in vivo. Further intraperitoneal (i.p.) injections of plasmid DNA expressing hpRNA for MMP-9 and cathepsin B completely regressed pre-established tumors for a long time (4 months) without any indication of these tumor cells. For the first time, these observations demonstrate that the simultaneous RNAi-mediated targeting of MMP-9 and cathepsin B has potential application for the treatment of human gliomas.
Assuntos
Catepsina B/antagonistas & inibidores , Regulação Neoplásica da Expressão Gênica , Glioblastoma/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Interferência de RNA , Animais , Western Blotting , Catepsina B/administração & dosagem , Divisão Celular/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Colágeno/metabolismo , Regulação para Baixo , Combinação de Medicamentos , Glioblastoma/irrigação sanguínea , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Injeções Intraperitoneais , Injeções Intraventriculares , Laminina/metabolismo , Metaloproteinase 9 da Matriz/administração & dosagem , Camundongos , Camundongos Nus , Modelos Biológicos , Invasividade Neoplásica , Transplante de Neoplasias , Neovascularização Patológica/genética , Proteoglicanas/metabolismo , Esferoides Celulares , Transplante HeterólogoRESUMO
Glioblastoma multiforme, the most common brain tumor, typically exhibits markedly increased angiogenesis, which is crucial for tumor growth and invasion. Antiangiogenic strategies based on disruption of the tumor microvasculature have proven effective for the treatment of experimental brain tumors. Here, we have overexpressed human caspase-9 by stable transfection in the SNB19 glioblastoma cell line, which normally expresses low levels of caspase-9. Our studies revealed that overexpression of caspase-9 coupled with radiation has a synergistic effect on the inhibition of glioma invasion as demonstrated by Matrigel assay (> 65%). Furthermore, sense caspase stable clones cocultured with fetal rat brain aggregates along with radiation showed complete inhibition as compared to the parental and vector controls. During in vitro angiogenesis, SNB19 cells cocultured with human microvascular endothelial cells (HMEC) showed vascular network formation after 48-72 h. In contrast, these capillary-like structures were inhibited when HMEC cells were cocultured with sense caspase stable SNB19 cells. This effect was further enhanced by radiation (5 Gy). Signaling mechanisms revealed that apoptosis is induced by cleavage of caspase-9 by radiation, loss of mitochondrial membrane potential and activation of caspase-3. These results demonstrate that activation of caspase-9 disrupts glioma cell invasion and angiogenesis in vitro. Hence, overexpression of proapoptotic molecules such as caspase-9 may be an important determinant of the therapeutic effect of radiation in cancer therapy.
Assuntos
Caspases/efeitos da radiação , Glioma/radioterapia , Invasividade Neoplásica , Neovascularização Patológica/radioterapia , Animais , Apoptose/efeitos da radiação , Capilares/enzimologia , Capilares/crescimento & desenvolvimento , Caspase 9 , Caspases/metabolismo , Citocromos c/biossíntese , Citocromos c/genética , Humanos , Potenciais da Membrana/fisiologia , Camundongos , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Proteínas Proto-Oncogênicas c-bcl-2/genéticaRESUMO
Increases in the abundance of cathepsin B transcript and protein with increased tumor grade and changes in subcellular localization and activity of this enzyme. We observed progressive reductions in levels of the protease inhibitor cystatin C, an inhibitor of cathepsin B with corresponding increases in the malignancy of glioma cell lines, implying an inverse correlation between cystatin C and tumor grade. To investigate the role of cystatin C in the invasion of brain tumor cells, we stably transfected SNB19 glioblastoma cells with either a 0.4-kb cDNA construct of human cystatin C in the sense orientation or an empty vector. Clones expressing sense-cystatin C cDNA had higher cystatin C mRNA and protein levels than did control cells. Sense-transfected cells were also markedly less invasive than control cells in a Matrigel invasion assay and in a coculture assay of SNB19 spheroids and fetal rat brain aggregates. Finally, the sense-transfected cells did not form tumors in nude mice upon intracerebral injection. These results strongly implicate cystatin C in the invasiveness of human glioblastoma cells and suggest that sense transcripts of cystatin C may prove useful in cancer therapy.
Assuntos
Neoplasias Encefálicas/patologia , Cistatinas/genética , Glioblastoma/patologia , Animais , Neoplasias Encefálicas/genética , Técnicas de Cocultura , Cistatina C , Regulação Neoplásica da Expressão Gênica/genética , Glioblastoma/genética , Humanos , Camundongos , Camundongos Nus , Transplante de Neoplasias , RNA Mensageiro/genética , Ratos , Transfecção , Células Tumorais CultivadasRESUMO
The binding of urokinase-type plasminogen activator (uPA) to its receptor (uPAR) on the surface of tumor cells is involved in the activation of proteolytic cascades responsible for the invasiveness of those cells. The diffuse, extensive infiltration of glioblastomas into the surrounding normal brain tissue is believed to rely on modifications of the proteolysis of extracellular matrix components; blocking the interaction between uPA and uPAR might be a suitable approach for inhibiting glioma tumorigenesis. We assessed how expression of an amino-terminal fragment (ATF) of uPA that contains binding site to uPAR affects the invasiveness of SNB19 human glioblastoma cells. SNB19 cells were transfected with an expression plasmid (pcDNA3-ATF) containing a cDNA sequence of ATF-uPA. The resulting ATF-uPA-expressing clones showed markedly less cell adhesion, spreading, and clonogenicity than did control cells. Endogenous ATF expression also significantly decreased the invasive capacity of transfected glioblastoma cells in Matrigel and spheroid-rat brain cell aggregate models. ATF-uPA transfectants were also markedly less invasive than parental SNB19 cells after injection into the brains of nude mice, suggesting that competitive inhibition of the uPA-uPAR interaction on SNB19 cells by means of transfection with ATF cDNA could be a useful therapeutic strategy for inhibiting tumor progression.
Assuntos
Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Invasividade Neoplásica/fisiopatologia , Proteínas de Neoplasias/fisiologia , Ativador de Plasminogênio Tipo Uroquinase/fisiologia , Actinas/metabolismo , Animais , Sítios de Ligação , Neoplasias Encefálicas/enzimologia , Neoplasias Encefálicas/terapia , Adesão Celular , Agregação Celular , Células Clonais/patologia , Colágeno , Citoesqueleto/ultraestrutura , DNA Complementar/genética , Combinação de Medicamentos , Terapia Genética , Glioblastoma/enzimologia , Glioblastoma/terapia , Humanos , Laminina , Camundongos , Camundongos Nus , Proteínas de Neoplasias/química , Proteínas de Neoplasias/genética , Estrutura Terciária de Proteína , Proteoglicanas , Ratos , Receptores de Superfície Celular/metabolismo , Receptores de Ativador de Plasminogênio Tipo Uroquinase , Proteínas Recombinantes de Fusão/fisiologia , Esferoides Celulares/patologia , Relação Estrutura-Atividade , Transfecção , Células Tumorais Cultivadas/patologia , Ensaio Tumoral de Célula-Tronco , Ativador de Plasminogênio Tipo Uroquinase/química , Ativador de Plasminogênio Tipo Uroquinase/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Urokinase-type plasminogen activator (uPA) and its receptor (uPAR) play an important role in the invasiveness of gliomas and other infiltrative tumors. In glioma cell lines and tumors, high grade correlates with increased expression of uPAR and uPA. We report here the downregulation of uPAR and uPA by delivery of antisense sequences of uPAR and uPA in a single adenoviral vector, Ad-uPAR-uPA (Ad, adenovirus). The bicistronic construct (Ad-uPAR-uPA) infected glioblastoma cell line had significantly reduced levels of uPAR, uPA enzymatic activity and immunoreactivity for these proteins when compared to controls. The Ad-uPAR-uPA infected cells showed a markedly lower level of invasion in the Matrigel invasion assays, and their spheroids failed to invade the fetal rat brain aggregates in the coculture system. Intracranial injection of SNB19 cells with the Ad-uPAR-uPA antisense bicistronic construct showed inhibited invasiveness and tumorigenicity. Subcutaneous injections of bicistronic antisense constructs into established tumors (U87 MG) caused regression of those tumors. Our results support the therapeutic potential of targeting the individual components of the uPAR-uPA system by using a single adenovirus construct for the treatment of glioma and other invasive cancers.
Assuntos
Neoplasias do Sistema Nervoso Central/genética , Neoplasias do Sistema Nervoso Central/terapia , Glioma/genética , Glioma/terapia , Neovascularização Patológica/terapia , Receptores de Superfície Celular/genética , Ativador de Plasminogênio Tipo Uroquinase/genética , Adenoviridae/genética , Animais , Testes de Carcinogenicidade , Movimento Celular , Neoplasias do Sistema Nervoso Central/irrigação sanguínea , Neoplasias do Sistema Nervoso Central/patologia , DNA Antissenso/administração & dosagem , DNA Antissenso/genética , Expressão Gênica , Terapia Genética/métodos , Vetores Genéticos/genética , Glioma/irrigação sanguínea , Glioma/patologia , Humanos , Camundongos , Camundongos Nus , Invasividade Neoplásica , Neovascularização Patológica/genética , Receptores de Superfície Celular/imunologia , Receptores de Superfície Celular/metabolismo , Receptores de Ativador de Plasminogênio Tipo Uroquinase , Células Tumorais Cultivadas , Ativador de Plasminogênio Tipo Uroquinase/imunologia , Ativador de Plasminogênio Tipo Uroquinase/metabolismoRESUMO
The cysteine proteinase cathepsin B has been implicated in tumor progression by virtue of its increased mRNA and protein levels, as well as its localization at the invading front of the tumor. In this study, we examined whether blocking cathepsin B expression in human glioblastoma SNB19 cells affects angiogenesis. Stable transfectants of human glioblastoma cells with a plasmid containing antisense cathepsin B cDNA showed decreased migration rates in wound- and spheroid-migration assays. Analysis showed a reduction in VEGF protein and MMP-9 activity in the cathepsin B antisense cDNA-transfected cells. Regarding angiogenesis in vitro, we found that the conditioned medium of glioblastoma cells with downregulated cathepsin B expression reduced cell-cell interaction of human microvascular endothelial cells, resulting in the disruption of capillary-like network formation. Furthermore, a marked reduction in microvasculature development was seen in an in vivo dorsal air sac assay of glioblastoma cells with downregulated cathepsin B expression. Taken together, these results provide evidence that inhibition of cathepsin B expression can suppress glioblastoma-induced neovascularization.
Assuntos
Inibidores da Angiogênese/farmacologia , Neoplasias Encefálicas/metabolismo , Catepsina B/antagonistas & inibidores , Glioblastoma/metabolismo , Neoplasias/irrigação sanguínea , Neovascularização Patológica , Animais , Bioensaio , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Movimento Celular , Cromonas/farmacologia , Meios de Cultivo Condicionados , Meios de Cultura Livres de Soro , Endotélio Vascular/citologia , Inibidores Enzimáticos/farmacologia , Flavonoides/farmacologia , Glioblastoma/genética , Glioblastoma/patologia , Humanos , Inibidores de Metaloproteinases de Matriz , Camundongos , Camundongos Nus , Morfolinas/farmacologia , Acetato de Tetradecanoilforbol/farmacologia , Transfecção , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
We have shown previously that the tissue factor pathway inhibitor-2 (TFPI-2), a broad range proteinase inhibitor, is highly expressed in low-grade gliomas, but, minimally expressed or undetectable in glioblastomas, and that enforced expression of this gene reduces the invasive properties of brain tumor cells. Here, we examined the role of promoter methylation as a mechanism of TFPI-2 gene silencing. In SNB19 glioblastoma cells, which have no detectable TFPI-2 expression, 5-aza-2'-deoxycytidine (5aC), an inhibitor of DNA methyltransferase, induced TFPI-2 mRNA in a dose-dependent manner. Trichostatin A (TSA), the histone deacetylase (HDAC) inhibitor, by itself, was more efficient than 5aC in inducing TFPI-2 transcripts, and the 5aC+TSA combination resulted in highly synergistic reactivation of the gene, both at the transcript and protein levels. In Hs683 glioma cells, which express the TFPI-2 gene at high levels, transfection of the in vitro methylated TFPI-2 promoter constructs resulted in a drastic decrease of promoter activity compared to the unmethylated promoter. Further, the methylation-specific PCR in SNB19 and Hs683 cells showed that TFPI-2 gene repression was closely linked with methylation of the CpG islands in the promoter. Finally, the chromatin immunoprecipitation assays in SNB19 cells showed that the methylated and repressed TFPI-2 promoter was associated with the methyl-CpG binding protein 2 (MeCP2), and that gene reactivation resulted in the loss of MeCP2 from this site. These studies establish that TFPI-2 is transcriptionally silenced through promoter methylation in SNB19 cells.