RESUMEN
UNLABELLED: First-generation EGFR tyrosine kinase inhibitors (EGFR TKI) provide significant clinical benefit in patients with advanced EGFR-mutant (EGFRm(+)) non-small cell lung cancer (NSCLC). Patients ultimately develop disease progression, often driven by acquisition of a second T790M EGFR TKI resistance mutation. AZD9291 is a novel oral, potent, and selective third-generation irreversible inhibitor of both EGFRm(+) sensitizing and T790M resistance mutants that spares wild-type EGFR. This mono-anilino-pyrimidine compound is structurally distinct from other third-generation EGFR TKIs and offers a pharmacologically differentiated profile from earlier generation EGFR TKIs. Preclinically, the drug potently inhibits signaling pathways and cellular growth in both EGFRm(+) and EGFRm(+)/T790M(+) mutant cell lines in vitro, with lower activity against wild-type EGFR lines, translating into profound and sustained tumor regression in EGFR-mutant tumor xenograft and transgenic models. The treatment of 2 patients with advanced EGFRm(+) T790M(+) NSCLC is described as proof of principle. SIGNIFICANCE: We report the development of a novel structurally distinct third-generation EGFR TKI, AZD9291, that irreversibly and selectively targets both sensitizing and resistant T790M(+) mutant EGFR while harboring less activity toward wild-type EGFR. AZD9291 is showing promising responses in a phase I trial even at the first-dose level, with first published clinical proof-of-principle validation being presented.
Asunto(s)
Acrilamidas/uso terapéutico , Compuestos de Anilina/uso terapéutico , Antineoplásicos/uso terapéutico , Resistencia a Antineoplásicos/genética , Receptores ErbB/antagonistas & inhibidores , Receptores ErbB/genética , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Mutación , Inhibidores de Proteínas Quinasas/uso terapéutico , Acrilamidas/química , Acrilamidas/farmacología , Compuestos de Anilina/química , Compuestos de Anilina/farmacología , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Receptores ErbB/química , Femenino , Genes erbB-2 , Humanos , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Modelos Moleculares , Conformación Molecular , Fosforilación , Unión Proteica , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Transducción de Señal/efectos de los fármacos , Resultado del Tratamiento , Carga Tumoral/efectos de los fármacos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
PURPOSE: Vascular endothelial growth factor (VEGF) signaling is key to tumor angiogenesis and is an important target in the development of anticancer drugs. However, VEGF receptor (VEGFR) expression in human cancers, particularly the relative expression of VEGFR-2 and VEGFR-3 in tumor vasculature versus tumor cells, is poorly defined. EXPERIMENTAL DESIGN: VEGFR-2- and VEGFR-3-specific antibodies were identified and used in the immunohistochemical analysis of human primary cancers and normal tissue. The relative vascular localization of both receptors in colorectal and breast cancers was determined by coimmunofluorescence with vascular markers. RESULTS: VEGFR-2 and VEGFR-3 were expressed on vascular endothelium but not on malignant cells in 13 common human solid tumor types (n > 400, bladder, breast, colorectal, head and neck, liver, lung, skin, ovarian, pancreatic, prostate, renal, stomach, and thyroid). The signal intensity of both receptors was significantly greater in vessels associated with malignant colorectal, lung, and breast than adjacent nontumor tissue. In colorectal cancers, VEGFR-2 was expressed on both intratumoral blood and lymphatic vessels, whereas VEGFR-3 was found predominantly on lymphatic vessels. In breast cancers, both receptors were localized to and upregulated on blood vessels. CONCLUSIONS: VEGFR-2 and VEGFR-3 are primarily localized to, and significantly upregulated on, tumor vasculature (blood and/or lymphatic) supporting the majority of solid cancers. The primary clinical mechanism of action of VEGF signaling inhibitors is likely to be through the targeting of tumor vessels rather than tumor cells. The upregulation of VEGFR-3 on tumor blood vessels indicates a potential additional antiangiogenic effect for dual VEGFR-2/VEGFR-3-targeted therapy.
Asunto(s)
Endotelio Vascular/metabolismo , Neoplasias Experimentales/metabolismo , Neoplasias/metabolismo , Receptor 2 de Factores de Crecimiento Endotelial Vascular/biosíntesis , Receptor 3 de Factores de Crecimiento Endotelial Vascular/biosíntesis , Animales , Western Blotting , Línea Celular Tumoral , Endotelio Vascular/patología , Humanos , Inmunohistoquímica , Ratones , Ratones Desnudos , Ratones SCID , Células 3T3 NIH , Trasplante de Neoplasias , Neoplasias/patología , Neoplasias Experimentales/patologíaRESUMEN
Antivascular agents that act by destabilizing microtubules, such as ZD6126 (N-acetylcolchinol-O-phosphate), are associated with adverse cardiovascular effects, including transient hypertension, cardiac ischemia, myocardial infarction, and increases in circulating levels of markers of cardiac damage (e.g., troponins). We investigated mechanisms underlying these effects of ZD6126 in rats by continuously monitoring their heart rate and blood pressure and by assessing heart histopathology and plasma troponin T levels. ZD6126 induced acute transient hemodynamic changes (hypertension and delayed tachycardia), which were associated with statistically significant increases in circulating troponin T levels (median level 3 hours after treatment with vehicle or 12.5 mg/kg ZD6126: <9 pg/mL and 563 pg/mL, respectively; P <.001 [two-sided Wilcoxon rank sum test]) and in the incidence of left ventricular myocardial fiber necrosis (incidence 24 hours after treatment with vehicle or 12.5 mg/kg ZD6126: 0/10 rats and 9/10 rats, respectively; P <.001 [two-sided Wilcoxon rank sum test]). Pretreatment of rats with atenolol and nifedipine ameliorated the acute hemodynamic changes and prevented ZD6126-induced increases in both troponin T and myocardial necrosis but did not prevent ZD6126-induced tumor necrosis in an Hras5 tumor xenograft model in nude rats. Our findings suggest that ZD6126-induced acute hemodynamic changes are a prerequisite for cardiac damage in rats.
Asunto(s)
Antiarrítmicos/farmacología , Antihipertensivos/farmacología , Antineoplásicos/toxicidad , Atenolol/farmacología , Hemodinámica/efectos de los fármacos , Hipertensión/prevención & control , Nifedipino/farmacología , Compuestos Organofosforados/toxicidad , Taquicardia/prevención & control , Antagonistas Adrenérgicos beta/farmacología , Animales , Antiarrítmicos/uso terapéutico , Antihipertensivos/uso terapéutico , Antineoplásicos/administración & dosificación , Atenolol/uso terapéutico , Biomarcadores/sangre , Bloqueadores de los Canales de Calcio/farmacología , Modelos Animales de Enfermedad , Esquema de Medicación , Femenino , Corazón/efectos de los fármacos , Hipertensión/inducido químicamente , Miocardio/patología , Neoplasias/tratamiento farmacológico , Nifedipino/uso terapéutico , Compuestos Organofosforados/administración & dosificación , Distribución Aleatoria , Ratas , Taquicardia/inducido químicamente , Trasplante Heterólogo , Troponina T/sangre , Vasodilatadores/farmacologíaRESUMEN
Magnetic resonance imaging (MRI) can measure the effects of therapies targeting the tumor vasculature and has demonstrated that vascular-damaging agents (VDA) induce acute vascular shutdown in tumors in human and animal models. However, at subtherapeutic doses, blood flow may recover before the induction of significant levels of necrosis. We present the relationship between changes in MRI biomarkers and tumor necrosis. Multiple MRI measurements were taken at 4.7 T in athymic rats (n = 24) bearing 1.94 +/- 0.2-cm3 subcutaneous Hras5 tumors (ATCC 41000) before and 24 hours after clinically relevant doses of the VDA, ZD6126 (0-10 mg/kg, i.v.). We measured effective transverse relaxation rate (R2*), initial area under the gadolinium concentration-time curve (IAUGC(60/150)), equivalent enhancing fractions (EHF(60/150)), time constant (K(trans)), proportion of hypoperfused voxels as estimated from fit failures in K(trans) analysis, and signal intensity (SI) in T2-weighted MRI (T(2)W). ZD6126 treatment induced > 90% dose-dependent tumor necrosis at 10 mg/kg; correspondingly, SI changes were evident from T2W MRI. Although R2* did not correlate, other MRI biomarkers significantly correlated with necrosis at doses of > or = 5 mg/kg ZD6126. These data on Hras5 tumors suggest that the quantification of hypoperfused voxels might provide a useful biomarker of tumor necrosis.
Asunto(s)
Imagen por Resonancia Magnética , Neoplasias Experimentales/tratamiento farmacológico , Compuestos Organofosforados/uso terapéutico , Animales , Biomarcadores , Relación Dosis-Respuesta a Droga , Genes ras , Masculino , Ratones , Células 3T3 NIH , Necrosis , Trasplante de Neoplasias , Neoplasias Experimentales/irrigación sanguínea , Neoplasias Experimentales/patología , Ratas , Ratas Desnudas , Trasplante HeterólogoRESUMEN
Tumours derived from DLD-1 colon adenocarcinoma cells, transfected to either overexpress inducible nitric oxide synthase (clone iNOS-19) or with empty vector (pBAN2R), were utilised to test the hypothesis that tumour expression of iNOS (a) increases tumour angiogenesis and (b) modulates the anti-tumour activity of the vascular disrupting agent ZD6126. Overexpression of iNOS by clone iNOS-19 cells and murine xenografts was confirmed by the Griess assay and western blot analysis respectively. Clone iNOS-19 tumours grew more rapidly than pBAN2R tumours. Tumour perfusion, assessed by Hoechst 33342 uptake, was significantly greater in the clone iNOS-19 tumours (P < 0.001). A significant reduction in the perfusion of only the pBAN2R tumours, compared with control, was obtained 24 h after treatment with an intermediate dose of 100 mg/kg ZD6126 (P < 0.001), whereas 200 mg/kg significantly reduced the perfusion of both tumour types (P < 0.001). Whilst pBAN2R tumour necrosis increased in a dose-dependent manner, significant at 100 and 200 mg/kg ZD6126 (P < 0.05), intermediate doses did not induce a similar degree of necrosis in clone iNOS-19 tumours. A significant reduction in splenic perfusion was found 24 h after treatment with 100 mg/kg ZD6126, primarily associated with the red pulp. Overexpression of iNOS increases tumour growth, the degree of functionally perfused vasculature and angiogenesis, and also confers resistance to the vascular disrupting agent ZD6126.
Asunto(s)
Antineoplásicos/farmacología , Neovascularización Patológica/enzimología , Neovascularización Patológica/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismo , Compuestos Organofosforados/farmacología , Adenocarcinoma/irrigación sanguínea , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Animales , Técnicas de Cultivo de Célula , Línea Celular Tumoral , Neoplasias del Colon/irrigación sanguínea , Neoplasias del Colon/metabolismo , Neoplasias del Colon/patología , Relación Dosis-Respuesta a Droga , Resistencia a Medicamentos , Humanos , Inyecciones Subcutáneas , Masculino , Ratones , Ratones Endogámicos , Ratones Desnudos , Trasplante de Neoplasias , Factores de Tiempo , Trasplante HeterólogoRESUMEN
Thymidine phosphorylase (TP) is an important target enzyme for cancer chemotherapy because it is expressed at high levels in the hypoxic regions of many tumors and inhibitors of TP have been shown in animal model studies to inhibit angiogenesis and metastasis, and to promote tumor cell apoptosis. The 5-halo-6-[(2'-aminoimidazol-1'-yl)methyl]uracils (3, X = Cl, Br) are very potent inhibitors of E. coli and human TP with IC(50) values of approximately 20 nM when the enzyme concentration is approximately 40 nM. Their 4'-aminoimidazol-1'-yl analogues (4, X = Cl, Br) are >350-fold less active with IC(50) values of approximately 7 microM. The 5-unsubstituted analogues (3 and 4, X = H) were both less active than their 5-halo derivatives. Determination of pK(a) values and molecular modeling studies of these compounds in the active site of human TP was used to rationalize their activities. The finding that 3, X = Br has a poor pharmacokinetic (PK) profile in mice, coupled with the desire for tumor selectivity, led us to design prodrugs. The corresponding 2'-nitroimidazol-1'-ylmethyluracils (5, X = Cl, Br) are >1000-fold less active (IC(50) 22-24 microM) than their 2'-amino analogues and are reduced to the 2'-amino inhibitors (3, X = Cl, Br) by xanthine oxidase (XO). As XO is also highly expressed in many tumors, the 2'-nitro prodrugs have the potential to selectively deliver the potent 2'-aminoimidazol-1'-yl TP inhibitors into hypoxic solid tumors.
Asunto(s)
Antineoplásicos/síntesis química , Imidazoles/síntesis química , Profármacos/síntesis química , Timidina Fosforilasa/antagonistas & inhibidores , Uracilo/análogos & derivados , Uracilo/síntesis química , Animales , Antineoplásicos/química , Antineoplásicos/farmacología , Sitios de Unión , Disponibilidad Biológica , Escherichia coli/química , Humanos , Imidazoles/química , Imidazoles/farmacología , Ratones , Modelos Moleculares , Nitroimidazoles/síntesis química , Nitroimidazoles/química , Nitroimidazoles/farmacología , Oxidación-Reducción , Profármacos/química , Profármacos/farmacología , Relación Estructura-Actividad , Uracilo/farmacologíaRESUMEN
PURPOSE: The aim of these studies was to evaluate factors that contribute to the selectivity of the novel vascular targeting agent ZD6126. METHODS: Human umbilical vein endothelial cells (HUVECs) were treated with ZD6126 phenol, and effects on morphology, detachment, and cytotoxicity (sulforhodamine-B dye incorporation) were determined. Hras5-transformed mouse 3T3 fibroblasts were implanted s.c. in athymic nude rats, and effects on the tumor were assessed after either i.v. bolus or 24-h minipump infusion of ZD6126. RESULTS: In vitro, ZD6126 phenol ( approximately 0.1 microm) rapidly (<40 min) destabilized the tubulin cytoskeleton of proliferating endothelial cells, resulting in cell shape change ("rounding up") and cell detachment at noncytotoxic drug concentrations. In vivo, in rats, an i.v. bolus dose of ZD6126 (20 mg/kg) was rapidly broken down to ZD6126 phenol, which has a short plasma elimination half-life ( approximately 1 h). Peak plasma levels of ZD6126 phenol were well above the level required to induce HUVEC morphology changes in vitro, but cytotoxic concentrations were not maintained. A single i.v. bolus dose (50 and 20 mg/kg) of ZD6126 was well tolerated and resulted in extensive central tumor necrosis in the Hras5 model. Administration of ZD6126 using a 24-h s.c. minipump resulted in decreased ( approximately 30-fold) peak plasma levels, but maintained cytotoxic drug levels over 24 h. Infusion of 50 mg/kg ZD6126 over 24 h was not tolerated. Infusion of 20 mg/kg ZD6126 resulted in increased toxicity compared with the i.v. bolus doses of ZD6126 and did not result in any increased tumor necrosis after 24 h. CONCLUSION: ZD6126 phenol induces rapid morphologic changes in HUVECs at noncytotoxic drug levels. These rapid morphologic effects combined with the rapid elimination of ZD6126 phenol contribute to the selective effects of ZD6126 on tumor vasculature at well-tolerated doses.
Asunto(s)
Inhibidores de la Angiogénesis/uso terapéutico , Endotelio Vascular/metabolismo , Neovascularización Patológica , Compuestos Organofosforados/uso terapéutico , Células 3T3 , Animales , División Celular , Línea Celular Transformada , Células Cultivadas , Relación Dosis-Respuesta a Droga , Endotelio Vascular/citología , Fibroblastos/metabolismo , Humanos , Ratones , Necrosis , Trasplante de Neoplasias , Ratas , Ratas Desnudas , Factores de Tiempo , Venas Umbilicales/citologíaRESUMEN
The epidermal growth factor receptor (EGFR) is a promising target for anticancer therapy because of its role in tumor growth, metastasis and angiogenesis, and tumor resistance to chemotherapy and radiotherapy. We have developed a low-molecular-weight EGFR tyrosine kinase inhibitor (EGFR-TKI), ZD1839 (Iressa(2) ). ZD1839, a substituted anilinoquinazoline, is a potent EGFR-TKI (IC(50) = 0.033 micro M) that selectively inhibits EGF-stimulated tumor cell growth (IC(50) = 0.054 micro M) and that blocks EGF-stimulated EGFR autophosphorylation in tumor cells. In studies with mice bearing a range of human tumor-derived xenografts, ZD1839 given p.o. once a day inhibited tumor growth in a dose-dependent manner. The level of expression of EGFR did not determine xenograft tumor sensitivity to ZD1839. Long-term ZD1839 (>3 months) treatment of mice bearing A431 xenografts was well tolerated, and ZD1839 completely inhibited tumor growth and induced regression of established tumors. No drug-resistant tumors appeared during ZD1839 treatment, but some tumors regrew after drug withdrawal. These studies indicate the potential utility of ZD1839 in the treatment of many human tumors and indicate that continuous once-a-day p.o. dosing might be a suitable therapeutic regimen.