RESUMEN
Type I interferon-mediated activation of immune cells can facilitate the generation of productive tumor antigen-specific T cell responses in solid tumors. The cGAS/STING DNA sensing pathway is a critical upstream mediator of type I interferon production and is an important regulator of anti-tumor immunity. Numerous STING pathway agonists are now being tested in clinical trials, but the effectiveness of this approach is not yet clear and a better understanding of the relative importance of this pathway in various tumor settings is needed. We have evaluated syngeneic tumor models with different baseline inflammatory states to determine the contributions of STING activity in both tumor and non-tumor cellular compartments to anti-tumor immune responses. We find that productive anti-tumor immune responses in the poorly immunogenic B16F10 model show a strong dependence on STING expression in non-tumor cells. In the immunogenic MC38 model, constitutive STING activation in tumor cells can partially bypass the requirement for STING-dependent activity from immune cells. Our findings reveal multiple, context-dependent roles for STING activity in the regulation of anti-tumor immunity and the response to immunotherapy. In preclinical models where STING is basally active, checkpoint inhibition is more likely to have a therapeutic effect and removal of STING signaling from either the tumor or the non-tumor compartment has a minimal effect. Removal of STING signaling in both, however, diminishes the efficacy derived from checkpoint therapy. Further work is needed to understand the heterogeneity of STING signaling in patients, both in tumor cells and the tumor microenvironment, and the best means of harnessing this pathway to generate anti-tumor immunity and improve therapeutic outcomes.
Asunto(s)
Interferón Tipo I , Neoplasias , Humanos , ADN , Inmunidad Innata , Inmunoterapia , Transducción de Señal , Microambiente TumoralRESUMEN
Tumor-associated macrophages (TAMs) are abundant in solid tumors where they exhibit immunosuppressive and pro-tumorigenic functions. Inhibition of TAM proliferation and survival through CSF1R blockade has been widely explored as a cancer immunotherapy. To further define mechanisms regulating CSF1R-targeted therapies, we systematically evaluated the effect of anti-CSF1R treatment on tumor growth and tumor microenvironment (TME) inflammation across multiple murine models. Despite substantial macrophage depletion, anti-CSF1R had minimal effects on the anti-tumor immune response in mice bearing established tumors. In contrast, anti-CSF1R treatment concurrent with tumor implantation resulted in more robust tumor growth inhibition and evidence of enhanced anti-tumor immunity. Our findings suggest only minor contributions of CSF1R-dependent TAMs to the inflammatory state of the TME in established tumors, that immune landscape heterogeneity across different tumor models can influence anti-CSF1R activity, and that alternative treatment schedules and/or TAM depletion strategies may be needed to maximize the clinical benefit of this approach.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias/inmunología , Neoplasias/terapia , Receptores de Factor Estimulante de Colonias de Granulocitos y Macrófagos/antagonistas & inhibidores , Macrófagos Asociados a Tumores/efectos de los fármacos , Animales , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Femenino , Inmunoterapia/métodos , Inflamación/tratamiento farmacológico , Inflamación/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Microambiente Tumoral/efectos de los fármacos , Microambiente Tumoral/inmunología , Macrófagos Asociados a Tumores/inmunologíaRESUMEN
Gas6 and its receptors Axl, Mer and Tyro-3 (TAM) are highly expressed in human malignancy suggesting that signaling through this axis may be tumor-promoting. In pancreatic ductal adenocarcinoma (PDAC), Gas6 and the TAM receptor Axl are frequently co-expressed and their co-expression correlates with poor survival. A strategy was devised to generate fully human neutralizing antibodies against Gas6 using XenoMouse® technology. Hybridoma supernatants were selected based on their ability to inhibit Gas6 binding to the receptor Axl and block Gas6-induced Axl phosphorylation in human cells. Two purified antibodies isolated from the screened hybridomas, GMAB1 and GMAB2, displayed optimal cellular potency which was comparable to that of the soluble extracellular domain of the receptor Axl (Axl-Fc). In vivo characterization of GMAB1 was conducted using a pharmacodynamic assay that measured inhibition of Gas6-induced Akt activation in the mouse spleen. Treatment of mice with a single dose (100-1000 µg) of GMAB1 led to greater than 90% inhibition of Gas6-induced phosphorylated Akt (pAkt) for up to 72 hr. Based on the target coverage observed in the PD assay, the efficacy of GMAB1 was tested against human pancreatic adenocarcinoma xenografts. At doses of 50 µg and 150 µg, twice weekly, GMAB1 was able to inhibit 55% and 76% of tumor growth, respectively (p < 0.001 for both treatments vs. control Ig). When combined with gemcitabine, GMAB1 significantly inhibited tumor growth compared to either agent alone (p < 0.001). Together, the data suggest that Gas6 neutralization may be important as a potential strategy for the treatment of PDAC.
Asunto(s)
Anticuerpos Neutralizantes/farmacología , Anticuerpos/farmacología , Comunicación Autocrina/efectos de los fármacos , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patología , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patología , Animales , Anticuerpos/inmunología , Anticuerpos Neutralizantes/inmunología , Antineoplásicos/farmacología , Carcinoma Ductal Pancreático/tratamiento farmacológico , Carcinoma Ductal Pancreático/inmunología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Ratones , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/inmunología , Fosforilación/efectos de los fármacos , Unión Proteica/efectos de los fármacos , Transporte de Proteínas/efectos de los fármacos , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto , Tirosina Quinasa del Receptor Axl , Neoplasias PancreáticasRESUMEN
Chromosomal instability (CIN) is a hallmark of cancer, caused by persistent errors in chromosome segregation during mitosis. Aggressive cancers like high-grade serous ovarian cancer (HGSOC) and triple-negative breast cancer (TNBC) have a high frequency of CIN and TP53 mutations. Here, we show that inhibitors of the KIF18A motor protein activate the mitotic checkpoint and selectively kill chromosomally unstable cancer cells. Sensitivity to KIF18A inhibition is enriched in TP53-mutant HGSOC and TNBC cell lines with CIN features, including in a subset of CCNE1-amplified, CDK4-CDK6-inhibitor-resistant and BRCA1-altered cell line models. Our KIF18A inhibitors have minimal detrimental effects on human bone marrow cells in culture, distinct from other anti-mitotic agents. In mice, inhibition of KIF18A leads to robust anti-cancer effects with tumor regression observed in human HGSOC and TNBC models at well-tolerated doses. Collectively, our results provide a rational therapeutic strategy for selective targeting of CIN cancers via KIF18A inhibition.
Asunto(s)
Cinesinas , Neoplasias de la Mama Triple Negativas , Humanos , Animales , Ratones , Cinesinas/genética , Cinesinas/metabolismo , Mitosis/genética , Línea Celular , Puntos de Control de la Fase M del Ciclo CelularRESUMEN
Liver metastasis is associated with immunotherapy resistance, although the underlying mechanisms remain incompletely understood. By applying single cell RNA-sequencing to a concurrent subcutaneous and liver tumor murine model to recapitulate liver metastases, it is identified that subsets within tumor-infiltrating exhausted CD8+ T (Tex) cells and immunosuppressive tumor-associated macrophages (TAMs) display opposite responses to concurrent liver tumors and anti-PD-1 treatment, suggesting a complex immune regulating network. Both angiogenic and interferon-reactive TAMs show increased frequencies in implanted liver tumors, and anti-PD-1 treatment further elevates the frequencies of angiogenic TAMs. Such TAMs frequencies negatively correlate with the proportions of cytotoxic T cell subsets. Further, expression of interferon-stimulated genes in TAMs is dramatically reduced under effective anti-PD-1 treatment, while such tendencies are diminished in mice with implanted liver tumors. Therefore, the study indicates that liver metastases could increase immunosuppressive TAMs frequencies and inhibit Tex responses to PD-1 blockade, resulting in compromised systemic antitumor immunity and limited immunotherapy efficacy.
RESUMEN
Chromosomal instability (CIN) is a hallmark of cancer that results from errors in chromosome segregation during mitosis. Targeting of CIN-associated vulnerabilities is an emerging therapeutic strategy in drug development. KIF18A, a mitotic kinesin, has been shown to play a role in maintaining bipolar spindle integrity and promotes viability of CIN cancer cells. To explore the potential of KIF18A, a series of inhibitors was identified. Optimization of an initial hit led to the discovery of analogues that could be used as chemical probes to interrogate the role of KIF18A inhibition. Compounds 23 and 24 caused significant mitotic arrest in vivo, which was sustained for 24 h. This would be followed by cell death either in mitosis or in the subsequent interphase. Furthermore, photoaffinity labeling experiments reveal that this series of inhibitors binds at the interface of KIF18A and tubulin. This study represents the first disclosure of KIF18A inhibitors with in vivo activity.
Asunto(s)
Cinesinas , Neoplasias , Muerte Celular , Humanos , Mitosis , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Huso Acromático/metabolismo , Tubulina (Proteína)/metabolismoRESUMEN
Therapeutic approaches are needed to promote T cell-mediated destruction of poorly immunogenic, "cold" tumors typically associated with minimal response to immune checkpoint blockade (ICB) therapy. Bispecific T cell engager (BiTE) molecules induce redirected lysis of cancer cells by polyclonal T cells and have demonstrated promising clinical activity against solid tumors in some patients. However, little is understood about the key factors that govern clinical responses to these therapies. Using an immunocompetent mouse model expressing a humanized CD3ε chain (huCD3e mice) and BiTE molecules directed against mouse CD19, mouse CLDN18.2, or human EPCAM antigens, we investigated the pharmacokinetic and pharmacodynamic parameters and immune correlates associated with BiTE efficacy across multiple syngeneic solid-tumor models. These studies demonstrated that pretreatment tumor-associated T cell density is a critical determinant of response to BiTE therapy, identified CD8+ T cells as important targets and mediators of BiTE activity, and revealed an antagonistic role for CD4+ T cells in BiTE efficacy. We also identified therapeutic combinations, including ICB and 4-1BB agonism, that synergized with BiTE treatment in poorly T cell-infiltrated, immunotherapy-refractory tumors. In these models, BiTE efficacy was dependent on local expansion of tumor-associated CD8+ T cells, rather than their recruitment from circulation. Our findings highlight the relative contributions of baseline T cell infiltration, local T cell proliferation, and peripheral T cell trafficking for BiTE molecule-mediated efficacy, identify combination strategies capable of overcoming resistance to BiTE therapy, and have clinical relevance for the development of BiTE and other T cell engager therapies.
Asunto(s)
Anticuerpos Biespecíficos , Neoplasias , Animales , Anticuerpos Biespecíficos/uso terapéutico , Antígenos CD19 , Complejo CD3 , Linfocitos T CD8-positivos , Claudinas , Humanos , Inmunoterapia , Ratones , Neoplasias/tratamiento farmacológicoRESUMEN
PURPOSE: Angiogenesis plays a critical role in breast cancer development and progression. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that regulates endothelial cell proliferation and survival. We investigated the effects of motesanib, a novel, oral inhibitor of VEGF receptors 1, 2, and 3; platelet-derived growth factor receptor; and Kit receptor, on the growth of xenografts representing various human breast cancer subtypes. EXPERIMENTAL DESIGN: Athymic nude mice were implanted with MCF-7 (luminal) or MDA-MB-231 (mesenchymal) tumor fragments or Cal-51 (mixed/progenitor) tumor cells. Once tumors were established, animals were randomized to receive increasing doses of motesanib alone or motesanib plus cytotoxic chemotherapy (docetaxel, doxorubicin, or tamoxifen). RESULTS: Across all three xenograft models, motesanib treatment resulted in significant dose-dependent reductions in tumor growth, compared with vehicle-treated controls, and in marked reductions in viable tumor fraction and blood vessel density. No significant effect on body weight was observed with compound treatment compared with control-treated animals. Motesanib did not affect the proliferation of tumor cells in vitro. There was a significantly greater reduction in xenograft tumor growth when motesanib was combined with docetaxel (MDA-MB-231 tumors) or with the estrogen receptor modulator tamoxifen (MCF-7 tumors), compared with either treatment alone, but not when combined with doxorubicin (Cal-51 tumors). CONCLUSIONS: Treatment with motesanib alone or in combination with chemotherapy inhibits tumor growth in vivo in various models of human breast cancer. These data suggest that motesanib may have broad utility in the treatment of human breast cancer.
Asunto(s)
Inhibidores de la Angiogénesis/uso terapéutico , Indoles/uso terapéutico , Neoplasias Mamarias Experimentales/tratamiento farmacológico , Niacinamida/análogos & derivados , Factor de Crecimiento Derivado de Plaquetas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-kit/metabolismo , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Peso Corporal/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Neoplasias Mamarias Experimentales/irrigación sanguínea , Ratones , Ratones Desnudos , Niacinamida/uso terapéutico , Oligonucleótidos , Distribución Aleatoria , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Overexpression of the antiapoptotic protein Mcl-1 provides a survival advantage to some cancer cells, making inhibition of this protein an attractive therapeutic target for the treatment of certain types of tumors. Herein, we report our efforts toward the identification of a novel series of macrocyclic Mcl-1 inhibitors featuring an α-hydroxy phenylacetic acid pharmacophore or bioisostere. This work led to the discovery of 1, a potent Mcl-1 inhibitor (IC50 = 19 nM in an OPM-2 cell viability assay) with good pharmacokinetic properties and excellent in vivo efficacy in an OPM-2 multiple myeloma xenograft model.
Asunto(s)
Antineoplásicos/química , Antineoplásicos/farmacología , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/antagonistas & inhibidores , Fenilacetatos/química , Administración Oral , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacocinética , Disponibilidad Biológica , Línea Celular Tumoral , Cristalografía por Rayos X , Diseño de Fármacos , Estabilidad de Medicamentos , Femenino , Humanos , Enlace de Hidrógeno , Ratones Desnudos , Mieloma Múltiple/tratamiento farmacológico , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/química , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Ratas Sprague-Dawley , Relación Estructura-Actividad , Sulfonamidas/química , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The prosurvival BCL2 family member MCL1 is frequently dysregulated in cancer. To overcome the significant challenges associated with inhibition of MCL1 protein-protein interactions, we rigorously applied small-molecule conformational restriction, which culminated in the discovery of AMG 176, the first selective MCL1 inhibitor to be studied in humans. We demonstrate that MCL1 inhibition induces a rapid and committed step toward apoptosis in subsets of hematologic cancer cell lines, tumor xenograft models, and primary patient samples. With the use of a human MCL1 knock-in mouse, we demonstrate that MCL1 inhibition at active doses of AMG 176 is tolerated and correlates with clear pharmacodynamic effects, demonstrated by reductions in B cells, monocytes, and neutrophils. Furthermore, the combination of AMG 176 and venetoclax is synergistic in acute myeloid leukemia (AML) tumor models and in primary patient samples at tolerated doses. These results highlight the therapeutic promise of AMG 176 and the potential for combinations with other BH3 mimetics. SIGNIFICANCE: AMG 176 is a potent, selective, and orally bioavailable MCL1 inhibitor that induces a rapid commitment to apoptosis in models of hematologic malignancies. The synergistic combination of AMG 176 and venetoclax demonstrates robust activity in models of AML at tolerated doses, highlighting the promise of BH3-mimetic combinations in hematologic cancers.See related commentary by Leber et al., p. 1511.This article is highlighted in the In This Issue feature, p. 1494.
RESUMEN
Purpose: Talimogene laherparepvec, a new oncolytic immunotherapy, has been recently approved for the treatment of melanoma. Using a murine version of the virus, we characterized local and systemic antitumor immune responses driving efficacy in murine syngeneic models.Experimental Design: The activity of talimogene laherparepvec was characterized against melanoma cell lines using an in vitro viability assay. Efficacy of OncoVEXmGM-CSF (talimogene laherparepvec with the mouse granulocyte-macrophage colony-stimulating factor transgene) alone or in combination with checkpoint blockade was characterized in A20 and CT-26 contralateral murine tumor models. CD8+ depletion, adoptive T-cell transfers, and Enzyme-Linked ImmunoSpot assays were used to study the mechanism of action (MOA) of systemic immune responses.Results: Treatment with OncoVEXmGM-CSF cured all injected A20 tumors and half of contralateral tumors. Viral presence was limited to injected tumors and was not responsible for systemic efficacy. A significant increase in T cells (CD3+/CD8+) was observed in injected and contralateral tumors at 168 hours. Ex vivo analyses showed these cytotoxic T lymphocytes were tumor-specific. Increased neutrophils, monocytes, and chemokines were observed in injected tumors only. Importantly, depletion of CD8+ T cells abolished all systemic efficacy and significantly decreased local efficacy. In addition, immune cell transfer from OncoVEXmGM-CSF-cured mice significantly protected from tumor challenge. Finally, combination of OncoVEXmGM-CSF and checkpoint blockade resulted in increased tumor-specific CD8+ anti-AH1 T cells and systemic efficacy.Conclusions: The data support a dual MOA for OncoVEXmGM-CSF that involves direct oncolysis of injected tumors and activation of a CD8+-dependent systemic response that clears injected and contralateral tumors when combined with checkpoint inhibition. Clin Cancer Res; 23(20); 6190-202. ©2017 AACR.
Asunto(s)
Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Inmunoterapia , Neoplasias/inmunología , Neoplasias/metabolismo , Viroterapia Oncolítica , Linfocitos T Citotóxicos/inmunología , Linfocitos T Citotóxicos/metabolismo , Adenoviridae/genética , Traslado Adoptivo , Animales , Línea Celular Tumoral , Modelos Animales de Enfermedad , Femenino , Terapia Genética/métodos , Vectores Genéticos/administración & dosificación , Vectores Genéticos/genética , Factor Estimulante de Colonias de Granulocitos y Macrófagos/genética , Humanos , Inmunomodulación , Inmunoterapia/métodos , Estimación de Kaplan-Meier , Depleción Linfocítica , Melanoma/inmunología , Melanoma/metabolismo , Melanoma/patología , Melanoma/terapia , Ratones , Neoplasias/patología , Neoplasias/terapia , Viroterapia Oncolítica/métodos , Transgenes , Carga Tumoral , Replicación Viral , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
PURPOSE: Insulin-like growth factor 1 receptor (IGF-IR) has been implicated in the pathogenesis of ovarian cancer. Ganitumab is an investigational, fully human monoclonal antibody against IGF-IR. Here, we explore the therapeutic potential of ganitumab for the treatment of ovarian cancer. EXPERIMENTAL DESIGN: The effects of ganitumab were tested in vitro against a panel of 23 established ovarian cancer cell lines. The ability of ganitumab to inhibit IGF-I-, IGF-II-, and insulin-mediated signaling was examined in vitro and in tumor xenografts using ovarian cancer models displaying IGF-IR/PI3K/AKT pathway activation by two distinct mechanisms, PTEN loss and IGF-II overexpression. Drug interactions between ganitumab and cisplatin, carboplatin, or paclitaxel were studied in vitro and in vivo. RESULTS: In vitro, growth inhibition varied significantly among individual ovarian cancer cell lines. IGF-II mRNA and phospho-IGF-IR protein expression were quantitatively correlated with response to ganitumab, and PTEN mutations conferred resistance to ganitumab. Ganitumab potently inhibited baseline and IGF-I-, IGF-II-, and insulin-induced IGF-IR and IGF-IR/insulin hybrid receptor signaling in vitro and in vivo. Synergistic and additive drug interactions were seen for ganitumab and carboplatin or paclitaxel in vitro. Furthermore, ganitumab significantly increased the efficacy of cisplatin in ovarian cancer xenograft models in vivo. CONCLUSIONS: These observations provide a biologic rationale to test ganitumab as a single agent or in combination with carboplatin/cisplatin and paclitaxel in patients with ovarian cancer. Moreover, assessment of tumor expression of IGF-II, phospho-IGF-IR, or PTEN status may help select patients with ovarian cancer who are most likely to benefit from ganitumab. Clin Cancer Res; 20(11); 2947-58. ©2014 AACR.
Asunto(s)
Anticuerpos Monoclonales/farmacología , Antineoplásicos/farmacología , Proliferación Celular/efectos de los fármacos , Neoplasias Ováricas/patología , Transducción de Señal/efectos de los fármacos , Animales , Anticuerpos Monoclonales Humanizados , Western Blotting , Carboplatino/administración & dosificación , Línea Celular Tumoral , Cisplatino/administración & dosificación , Sinergismo Farmacológico , Femenino , Citometría de Flujo , Humanos , Factor II del Crecimiento Similar a la Insulina/metabolismo , Ratones , Ratones Desnudos , Neoplasias Ováricas/genética , Fosfohidrolasa PTEN/genética , Paclitaxel/administración & dosificación , Receptor IGF Tipo 1/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transcriptoma , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Raf inhibitors are under clinical investigation, specifically in patients with tumor types harboring frequent activating mutations in B-Raf. Here, we show that cell lines and tumors harboring mutant B-Raf were sensitive to a novel series of Raf inhibitors (e.g., (V600E)B-Raf A375, IC(50) on cells = 2 nmol/L; ED(50) on tumor xenografts = 1.3 mg/kg). However, in cells and tumors with wild-type B-Raf, exposure to Raf inhibitors resulted in a dose-dependent and sustained activation of mitogen-activated protein kinase signaling. In some of these cell lines, Raf inhibition led to entry into the cell cycle, enhanced proliferation, and significantly stimulated tumor growth in vivo. Inhibition with structurally distinct Raf inhibitors or isoform-specific small interfering RNA knockdown of Raf showed that these effects were mediated directly through Raf. Either A-Raf or C-Raf mediated the Raf inhibitor-induced mitogen-activated protein kinase pathway activation in an inhibitor-specific manner. These paradoxical effects of Raf inhibition were seen in malignant and normal cells in vitro and in vivo. Hyperplasia of normal epithelial cells in the esophagus and the stomach was evident in mice with all efficacious Raf inhibitors (n = 8) tested. An implication of these results is that Raf inhibitors may induce unexpected normal cell and tumor tissue proliferation in patients.
Asunto(s)
Neoplasias/patología , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Animales , Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Activación Enzimática/efectos de los fármacos , Epitelio/efectos de los fármacos , Epitelio/patología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Hiperplasia , Péptidos y Proteínas de Señalización Intercelular/farmacología , Isoenzimas/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/genética , Ratones , Proteínas Mutantes/metabolismo , Neoplasias/enzimología , Inhibidores de Proteínas Quinasas/administración & dosificación , Proteínas Proto-Oncogénicas B-raf/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Epidermal growth factor receptor (EGFR) kinase domain mutations cause hyperresponsiveness to ligand and hypersensitivity to small-molecule tyrosine kinase inhibitors. However, little is known about how these mutations respond to antibodies against EGFR. We investigated the activity of panitumumab, a fully human anti-EGFR monoclonal antibody, in vitro in mutant EGFR-expressing non-small cell lung carcinoma (NSCLC) cells and in vivo with chemotherapy in xenograft models. Mutant EGFR-expressing NSCLC cells (NCI-H1975 [L858R+T790M] and NCI-H1650 [Delta746-750]) and CHO cells were treated with panitumumab before EGF stimulation to assess the inhibition of EGFR autophosphorylation. Established tumors were treated with panitumumab (25, 100, or 500 mug/mouse twice a week) alone or with docetaxel (10 or 20 mg/kg once a week) or cisplatin (7.5 mg/kg once a week). Antitumor activity and levels of proliferation markers were analyzed. Treatment of mutant EGFR-expressing CHO and NSCLC cells with panitumumab inhibited ligand-dependent autophosphorylation. In NCI-H1975 and NCI-H1650 xenografts, treatment with panitumumab alone or with cisplatin inhibited tumor growth compared with control (P < 0.0003). With panitumumab plus docetaxel, enhanced antitumor activity was seen in both xenografts versus panitumumab alone. Panitumumab treatment alone decreased Ki-67 and phospho- mitogen-activated protein kinase (pMAPK) staining in both xenografts compared with control. Docetaxel enhanced panitumumab activity in NCI-H1650 xenografts (decreased Ki-67 and pMAPK staining by >60%) when compared with either agent alone. Panitumumab inhibits ligand-induced EGFR phosphorylation, tumor growth, and markers of proliferation alone or with docetaxel in NSCLC cell lines that express clinically observed EGFR kinase domain mutations, including the small-molecule tyrosine kinase inhibitor-resistant T790M mutation.
Asunto(s)
Anticuerpos Monoclonales/farmacología , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Receptores ErbB/metabolismo , Neoplasias Pulmonares/tratamiento farmacológico , Animales , Anticuerpos Monoclonales/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Western Blotting , Células CHO , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/patología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Cisplatino/administración & dosificación , Cricetinae , Cricetulus , Docetaxel , Receptores ErbB/genética , Receptores ErbB/inmunología , Humanos , Inmunohistoquímica , Antígeno Ki-67/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Ratones , Ratones Desnudos , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Mutación , Panitumumab , Fosforilación/efectos de los fármacos , Taxoides/administración & dosificación , Carga Tumoral/efectos de los fármacos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Pancreatic carcinoma is a leading cause of cancer deaths, and recent clinical trials of a number of oncology therapeutics have not substantially improved clinical outcomes. We have evaluated the therapeutic potential of AMG 479, a fully human monoclonal antibody against insulin-like growth factor (IGF) type I receptor (IGF-IR), in two IGF-IR-expressing pancreatic carcinoma cell lines, BxPC-3 and MiaPaCa2, which also differentially express insulin receptor (INSR). AMG 479 bound to IGF-IR (K(D) 0.33 nmol/L) and blocked IGF-I and IGF-II binding (IC(50) < 0.6 nmol/L) without cross-reacting to INSR. AMG 479 completely inhibited ligand-induced (IGF-I, IGF-II, and insulin) activation of IGF-IR homodimers and IGF-IR/INSR hybrids (but not INSR homodimers) leading to reduced cellular viability in serum-deprived cultures. AMG 479 inhibited >80% of basal IGF-IR activity in BxPC-3 and MiaPaCa2 xenografts and prevented IGF-IR and IGF-IR/INSR hybrid activation following challenge with supraphysiologic concentrations of IGF-I. As a single agent, AMG 479 inhibited (â¼ 80%) the growth of pancreatic carcinoma xenografts, and long-term treatment was associated with reduced IGF-IR signaling activity and expression. Efficacy seemed to be the result of two distinct biological effects: proapoptotic in BxPC-3 and antimitogenic in MiaPaCa2. The combination of AMG 479 with gemcitabine resulted in additive inhibitory activity both in vitro and in vivo. These results indicate that AMG 479 is a clinical candidate, both as a single agent and in combination with gemcitabine, for the treatment of patients with pancreatic carcinoma