RESUMEN
Despite the advances in imaging, surgery and radiotherapy, the majority of patients with brainstem gliomas die within 2 years after initial diagnosis. Factors that contribute to the dismal prognosis of these patients include the infiltrative nature and anatomic location in an eloquent area of the brain, which prevents total surgical resection and the presence of the blood-brain barrier (BBB), which reduces the distribution of systemically administered agents. The development of new therapeutic approaches which can circumvent the BBB is a potential path to improve outcomes for these children. Convection-enhanced delivery (CED) and intranasal delivery (IND) are strategies that permit direct drug delivery into the central nervous system and are an alternative to intravenous injection (IV). We treated rats bearing human brainstem tumor xenografts with nanoliposomal irinotecan (CPT-11) using CED, IND, and IV. A single treatment of CED irinotecan had a similar effect on overall survival as multiple treatments by IV route. IND CPT-11 showed significantly increased survival of animals with brainstem tumors, and demonstrated the promise of this non-invasive approach of drug delivery bypassing the BBB when combined with nanoliposomal chemotherapy. Our results indicated that using CED and IND of nanoliposomal therapy increase likelihood of practical therapeutic approach for the treatment of brainstem gliomas.
Asunto(s)
Neoplasias del Tronco Encefálico/tratamiento farmacológico , Irinotecán/administración & dosificación , Inhibidores de Topoisomerasa I/administración & dosificación , Administración Intranasal , Animales , Neoplasias del Tronco Encefálico/mortalidad , Línea Celular Tumoral , Convección , Portadores de Fármacos , Humanos , Irinotecán/farmacocinética , Liposomas , Masculino , Nanoestructuras , Ratas , Inhibidores de Topoisomerasa I/farmacocinética , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Therapeutics at or close to the nanoscale, such as liposomal irinotecan, offer significant promise for the treatment of solid tumors. Their potential advantage over the unencapsulated or free form of the drug is due in part to their altered biodistribution. For slow and sustained release, significant optimization of formulation is needed to achieve the required level of stability and allow long-term storage of the drug product. Gradient-based liposomal formulation of camptothecins such as irinotecan poses unique challenges owing to the camptothecin- and acid-catalyzed hydrolysis of phospholipid esters in the inner monolayer of the liposomal membrane. We demonstrated that a narrow set of conditions related to the external pH, temperature, intraliposomal concentration, identity of the drug-trapping agent, physical form of the drug inside the liposomes, and final drug load have a marked impact on the stability of the liposome phospholipid membrane. The physical form of the drug inside the liposome was shown to be an insoluble gel with an irinotecan-to-sulfate ratio approximating 1:1, reducing the potential for irinotecan-catalyzed phospholipid hydrolysis in the internal phospholipid monolayer. As a result of this work, a stable and active liposome formulation has been developed that maintains phospholipid chemical stability following long-term storage at 2-8°C.
Asunto(s)
Liposomas , Fosfolípidos , Irinotecán , Estabilidad de Medicamentos , Distribución Tisular , Camptotecina , CatálisisRESUMEN
Effective liposomal formulations of vinorelbine (5' nor-anhydro-vinblastine; VRL) have been elusive due to vinorelbine's hydrophobic structure and resulting difficulty in stabilizing the drug inside the nanocarrier. Triethylammonium salts of several polyanionic trapping agents were used initially to prepare minimally pegylated nanoliposomal vinorelbine formulations with a wide range of drug release rates. Sulfate, poly(phosphate), and sucrose octasulfate were used to stabilize vinorelbine intraliposomally while in circulation, with varying degrees of effectiveness. The release rate of vinorelbine from the liposomal carrier was affected by both the chemical nature of the trapping agent and the resulting drug-to-lipid ratio, with liposomes prepared using sucrose octasulfate displaying the longest half-life in circulation (9.4 h) and in vivo retention in the nanoparticle (t(1/2) = 27.2 h). Efficacy was considerably improved in both a human colon carcinoma (HT-29) and a murine (C-26) colon carcinoma model when vinorelbine was stably encapsulated in liposomes using triethylammonium sucrose octasulfate. Early difficulties in preparing highly pegylated formulations were later overcome by substituting a neutral distearoylglycerol anchor for the more commonly used anionic distearoylphosphatidylethanolamine anchor. The new pegylated nanoliposomal vinorelbine displayed high encapsulation efficiency and in vivo drug retention, and it was highly active against human breast and lung tumor xenografts. Acute toxicity of the drug in immunocompetent mice slightly decreased upon encapsulation in liposomes, with a maximum tolerated dose of 17.5 mg VRL/kg for free vinorelbine and 23.8 mg VRL/kg for nanoliposomal vinorelbine. Our results demonstrate that a highly active, stable, and long-circulating liposomal vinorelbine can be prepared and warrants further study in the treatment of cancer.
Asunto(s)
Vinblastina/análogos & derivados , Portadores de Fármacos , Estabilidad de Medicamentos , Humanos , Liposomas , Nanopartículas , Fosfolípidos/sangre , Tritio , Vinblastina/química , Vinblastina/farmacocinética , VinorelbinaRESUMEN
Ephrin A2 targeted immunoliposomes incorporating pH-sensitive taxane prodrugs were developed for sustained delivery of active drug to solid tumors. Here we describe the systematic formulation development and characterization of these immunoliposomes. We synthesized both paclitaxel and docetaxel prodrugs to formulate as ephrin A2-targeted liposomes stabilized in the aqueous core with sucroseoctasulfate (SOS). The optimized lipid formulation was comprised of egg-sphingomyelin, cholesterol, and polyethylene glycol distearoyl glycerol (PEG-DSG). The formulations examined had a high efficiency of prodrug encapsulation (as high as 114â¯mol% taxane per mole phospholipid) and subsequent stability (>3â¯years at 2-8⯰C). The taxane prodrug was stabilized with extraliposomal citric acid and subsequently loaded into liposomes containing a gradient of SOS, resulting in highly stable SOS-drug complexes being formed inside the liposome. The internal prodrug and SOS concentrations were optimized for their impact on in vivo drug release and drug degradation. Cryo-electron microscope images revealed dense prodrug-SOS complex in the aqueous core of the immunoliposomes. Ephrin A2-targeted taxane liposomes exhibited sub-nanomolar (0.69â¯nM) apparent equilibrium dissociation constant toward the extracellular domain of the ephrin A2 receptor, long circulation half-life (8-12â¯h) in mouse plasma, a release rate dependent on intraliposomal drug concentration and stable long-term storage. At an equitoxic dose of 50â¯mg taxane/kg, ephrin A2-targeted liposomal prodrug showed greater antitumor activity than 10â¯mg/kg of docetaxel in A549 non-small cell lung, as well as MDA-MB-436 and SUM149 triple negative breast cancer xenograft models. The lead molecule entered a Phase I clinical trial in patients with solid tumors (NCT03076372).
Asunto(s)
Antineoplásicos/administración & dosificación , Hidrocarburos Aromáticos con Puentes/administración & dosificación , Portadores de Fármacos/química , Efrina-A2/metabolismo , Nanopartículas/química , Profármacos/administración & dosificación , Taxoides/administración & dosificación , Células A549 , Animales , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/farmacología , Hidrocarburos Aromáticos con Puentes/química , Hidrocarburos Aromáticos con Puentes/farmacocinética , Hidrocarburos Aromáticos con Puentes/farmacología , Línea Celular Tumoral , Composición de Medicamentos , Liberación de Fármacos , Femenino , Humanos , Liposomas , Ratones Desnudos , Tamaño de la Partícula , Profármacos/química , Profármacos/farmacocinética , Profármacos/farmacología , Unión Proteica , Taxoides/química , Taxoides/farmacocinética , Taxoides/farmacología , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Antibody-mediated tumour targeting and nanoparticle-mediated encapsulation can reduce the toxicity of antitumour drugs and improve their efficacy. Here, we describe the performance of a nanotherapeutic encapsulating a hydrolytically sensitive docetaxel prodrug and conjugated to an antibody specific for EphA2-a receptor overexpressed in many tumours. Administration of the nanotherapeutic in mice led to slow and sustained release of the prodrug, reduced exposure of active docetaxel in the circulation (compared with administration of the free drug) and maintenance of optimal exposure of the drug in tumour tissue. We also show that administration of the nanotherapeutic in rats and dogs resulted in minimal haematological toxicity, as well as the absence of neutropenia and improved overall tolerability in multiple rodent models. Targeting of the nanotherapeutic to EphA2 improved tumour penetration and resulted in markedly enhanced antitumour activity (compared with administration of free docetaxel and non-targeted nanotherapeutic controls) in multiple tumour-xenografted mice. This nanomedicine could become a potent and safe therapeutic alternative for cancer patients undergoing chemotherapy.
Asunto(s)
Antineoplásicos/uso terapéutico , Nanopartículas/uso terapéutico , Receptor EphA2/metabolismo , Animales , Antineoplásicos/farmacología , Hidrocarburos Aromáticos con Puentes/farmacología , Hidrocarburos Aromáticos con Puentes/uso terapéutico , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Docetaxel/sangre , Docetaxel/química , Docetaxel/farmacocinética , Docetaxel/uso terapéutico , Humanos , Liposomas , Ratones Endogámicos NOD , Ratones SCID , Taxoides/farmacología , Taxoides/uso terapéutico , Distribución Tisular/efectos de los fármacos , Carga Tumoral/efectos de los fármacos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
OBJECT: Many factors relating to the safety and efficacy of convection-enhanced delivery (CED) into intracranial tumors are poorly understood. To investigate these factors further and establish a more clinically relevant large animal model, with the potential to investigate CED in large, spontaneous tumors, the authors developed a magnetic resonance (MR) imaging-compatible system for CED of liposomal nanoparticles into the canine brain, incorporating real-time MR imaging. Additionally any possible toxicity of liposomes containing Gd and the chemotherapeutic agent irinotecan (CPT-11) was assessed following direct intraparenchymal delivery. METHODS: Four healthy laboratory dogs were infused with liposomes containing Gd, rhodamine, or CPT-11. Convection-enhanced delivery was monitored in real time by sequential MR imaging, and the volumes of distribution were calculated from MR images and histological sections. Assessment of any toxicity was based on clinical and histopathological evaluation. Convection-enhanced delivery resulted in robust volumes of distribution in both gray and white matter, and real-time MR imaging allowed accurate calculation of volumes and pathways of distribution. RESULTS: Infusion variability was greatest in the gray matter, and was associated with leakage into ventricular or subarachnoid spaces. Complications were minimal and included mild transient proprioceptive deficits, focal hemorrhage in 1 dog, and focal, mild perivascular, nonsuppurative encephalitis in 1 dog. CONCLUSIONS: Convection-enhanced delivery of liposomal Gd/CPT-11 is associated with minimal adverse effects in a large animal model, and further assessment for use in clinical patients is warranted. Future studies investigating real-time monitored CED in spontaneous gliomas in canines are feasible and will provide a unique, clinically relevant large animal translational model for testing this and other therapeutic strategies.
Asunto(s)
Camptotecina/análogos & derivados , Imagen por Resonancia Magnética , Animales , Encéfalo/metabolismo , Camptotecina/administración & dosificación , Camptotecina/farmacocinética , Camptotecina/toxicidad , Perros , Monitoreo del Ambiente , Femenino , Fluorescencia , Gadolinio , Irinotecán , Liposomas , NanopartículasRESUMEN
Liposome formulations of camptothecins have been actively pursued because of the potential for significant pharmacologic advantages from successful drug delivery of this important class of anticancer drugs. We describe nanoliposomal CPT-11, a novel nanoparticle/liposome construct containing CPT-11 (irinotecan) with unprecedented drug loading efficiency and in vivo drug retention. Using a modified gradient loading method featuring a sterically hindered amine with highly charged, multivalent anionic trapping agents, either polymeric (polyphosphate) or nonpolymeric (sucrose octasulfate), liposomes were capable of entrapping CPT-11 at extremely high drug-to-lipid ratios (>800 g CPT-11/mol phospholipid) and retaining encapsulated drug in vivo with a half-life of drug release in the circulation of 56.8 hours. CPT-11 was also protected from hydrolysis to the inactive carboxylate form and from metabolic conversion to SN-38 while circulating. The maximum tolerated dose in normal mice was determined to be 80 mg/kg for free CPT-11 and >320 mg/kg for nanoliposomal CPT-11. Nanoliposomal CPT-11 showed markedly superior efficacy when compared with free CPT-11 in human breast (BT474) and colon (HT29) cancer xenograft models. This study shows that intraliposomal stabilization of CPT-11 using a polymeric or highly charged, nonpolymeric polyanionic trapping agent results in a markedly active antitumor agent with low toxicity.
Asunto(s)
Camptotecina/análogos & derivados , Sistemas de Liberación de Medicamentos/métodos , Liposomas/química , Nanoestructuras/química , Animales , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/metabolismo , Camptotecina/administración & dosificación , Camptotecina/química , Camptotecina/farmacocinética , Camptotecina/toxicidad , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/metabolismo , Estabilidad de Medicamentos , Femenino , Células HT29 , Humanos , Irinotecán , Liposomas/administración & dosificación , Liposomas/farmacocinética , Liposomas/toxicidad , Ratones , Ratones Desnudos , Nanoestructuras/toxicidad , Ratas , Ratas Sprague-Dawley , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
We hypothesized that combining convection-enhanced delivery (CED) with a novel, highly stable nanoparticle/liposome containing CPT-11 (nanoliposomal CPT-11) would provide a dual drug delivery strategy for brain tumor treatment. Following CED in rat brains, tissue retention of nanoliposomal CPT-11 was greatly prolonged, with >20% injected dose remaining at 12 days for all doses. Tissue residence was dose dependent, with doses of 60 microg (3 mg/mL), 0.8 mg (40 mg/mL), and 1.6 mg (80 mg/mL) resulting in tissue half-life (t(1/2)) of 6.7, 10.7, and 19.7 days, respectively. In contrast, CED of free CPT-11 resulted in rapid drug clearance (tissue t(1/2) = 0.3 day). At equivalent CED doses, nanoliposomal CPT-11 increased area under the time-concentration curve by 25-fold and tissue t(1/2) by 22-fold over free CPT-11; CED in intracranial U87 glioma xenografts showed even longer tumor retention (tissue t(1/2) = 43 days). Plasma levels were undetectable following CED of nanoliposomal CPT-11. Importantly, prolonged exposure to nanoliposomal CPT-11 resulted in no measurable central nervous system (CNS) toxicity at any dose tested (0.06-1.6 mg/rat), whereas CED of free CPT-11 induced severe CNS toxicity at 0.4 mg/rat. In the intracranial U87 glioma xenograft model, a single CED infusion of nanoliposomal CPT-11 at 1.6 mg resulted in significantly improved median survival (>100 days) compared with CED of control liposomes (19.5 days; P = 4.9 x 10(-5)) or free drug (28.5 days; P = 0.011). We conclude that CED of nanoliposomal CPT-11 greatly prolonged tissue residence while also substantially reducing toxicity, resulting in a highly effective treatment strategy in preclinical brain tumor models.
Asunto(s)
Neoplasias Encefálicas/tratamiento farmacológico , Camptotecina/análogos & derivados , Sistemas de Liberación de Medicamentos/métodos , Animales , Neoplasias Encefálicas/metabolismo , Camptotecina/administración & dosificación , Camptotecina/química , Camptotecina/farmacocinética , Camptotecina/toxicidad , Línea Celular Tumoral , Convección , Humanos , Irinotecán , Liposomas/administración & dosificación , Liposomas/química , Liposomas/farmacocinética , Liposomas/toxicidad , Masculino , Nanoestructuras/química , Nanoestructuras/toxicidad , Fosfolípidos/administración & dosificación , Fosfolípidos/química , Fosfolípidos/farmacocinética , Fosfolípidos/toxicidad , Ratas , Ratas Sprague-Dawley , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Despite multimodal treatment options, the response and survival rates for patients with malignant gliomas remain dismal. Clinical trials with convection-enhanced delivery (CED) have recently opened a new window in neuro-oncology to the direct delivery of chemotherapeutics to the CNS, circumventing the blood-brain barrier and reducing systemic side effects. Our previous CED studies with liposomal chemotherapeutics have shown promising antitumor activity in rodent brain tumor models. In this study, we evaluated a combination of nanoliposomal topotecan (nLs-TPT) and pegylated liposomal doxorubicin (PLD) to enhance efficacy in our brain tumor models, and to establish a CED treatment capable of improving survival from malignant brain tumors. Both liposomal drugs decreased key enzymes involved in tumor cell replication in vitro. Synergistic effects of nLs-TPT and PLD on U87MG cell death were found. The combination displayed excellent efficacy in a CED-based survival study 10 days after tumor cell implantation. Animals in the control group and those in singleagent groups had a median survival of less than 30 days, whereas the combination group experienced a median survival of more than 90 days. We conclude that CED of two liposomal chemotherapeutics (nLs-TPT and PLD) may be an effective treatment option for malignant gliomas.
Asunto(s)
Neoplasias Encefálicas/tratamiento farmacológico , Doxorrubicina/análogos & derivados , Sistemas de Liberación de Medicamentos , Glioblastoma/tratamiento farmacológico , Polietilenglicoles/administración & dosificación , Inhibidores de Topoisomerasa I , Inhibidores de Topoisomerasa II , Topotecan/administración & dosificación , Animales , Antineoplásicos/administración & dosificación , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Doxorrubicina/administración & dosificación , Glioblastoma/patología , Humanos , Masculino , Ratas , Ratas Desnudas , Ratas Sprague-Dawley , Tasa de Supervivencia , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
We have previously shown that convection-enhanced delivery (CED) of highly stable nanoparticle/liposome agents encapsulating chemotherapeutic drugs is effective against intracranial rodent brain tumor xenografts. In this study, we have evaluated the combination of a newly developed nanoparticle/liposome containing the topoisomerase I inhibitor CPT-11 (nanoliposomal CPT-11 [nLs-CPT-11]), and PEGylated liposomal doxorubicin (Doxil) containing the topoisomerase II inhibitor doxorubicin. Both drugs were detectable in the CNS for more than 36 days after a single CED application. Tissue half-life was 16.7 days for nLs-CPT-11 and 10.9 days for Doxil. The combination of the two agents produced synergistic cytotoxicity in vitro. In vivo in U251MG and U87MG intracranial rodent xenograft models, CED of the combination was also more efficacious than either agent used singly. Analysis of the parameters involved in this approach indicated that tissue pharmacokinetics, tumor microanatomy, and biochemical interactions of the drugs all contributed to the therapeutic efficacy observed. These findings have implications for further clinical applications of CED-based treatment of brain tumors.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Neoplasias Encefálicas/tratamiento farmacológico , Camptotecina/análogos & derivados , Doxorrubicina/administración & dosificación , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Camptotecina/administración & dosificación , Camptotecina/efectos adversos , Camptotecina/farmacocinética , Línea Celular Tumoral , Convección , Doxorrubicina/efectos adversos , Doxorrubicina/farmacocinética , Sinergismo Farmacológico , Semivida , Humanos , Irinotecán , Liposomas , Masculino , Nanopartículas , Trasplante de Neoplasias , Ratas , Ratas Sprague-Dawley , Distribución Tisular , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
We previously reported the development of epidermal growth factor receptor (EGFR)-targeted immunoliposomes that bind and internalize in tumor cells which overexpress EGFR and/or mutant EGFR variant III (EGFRvIII), enabling intracellular delivery of potent anticancer agents in vitro. We now describe in vivo proof-of-concept for this approach for the delivery of multiple anticancer drugs in EGFR-overexpressing tumor models. Anti-EGFR immunoliposomes were constructed modularly with Fab' fragments of cetuximab (IMC-C225), covalently linked to liposomes containing probes and/or anticancer drugs. Pharmacokinetic and biodistribution studies confirmed long circulation times (t(1/2) = 21 hours) and efficient accumulation in tumors (up to 15% ID/g) irrespective of the presence of the targeting ligand. Although total accumulations of anti-EGFR immunoliposomes and nontargeted liposomes in EGFR-overexpressing tumors were comparable, only immunoliposomes internalized extensively within tumor cells (92% of analyzed cells versus <5% for nontargeted liposomes), indicating different mechanisms of delivery at the cellular level. In vivo therapy studies in a series of xenograft models featuring overexpression of EGFR and/or EGFRvIII showed the superiority of immunoliposomal delivery of encapsulated drugs, which included doxorubicin, epirubicin, and vinorelbine. For each of these drugs, anti-EGFR immunoliposome delivery showed significant antitumor effects and was significantly superior to all other treatments, including the corresponding free or liposomal drug (P < 0.001-0.003). We conclude that anti-EGFR immunoliposomes provide efficient and targeted drug delivery of anticancer compounds and may represent a useful new treatment approach for tumors that overexpress the EGFR.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Receptores ErbB/efectos de los fármacos , Glioblastoma/tratamiento farmacológico , Inmunoconjugados/uso terapéutico , Liposomas/administración & dosificación , Animales , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales Humanizados , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Neoplasias Encefálicas/tratamiento farmacológico , Neoplasias Encefálicas/inmunología , Neoplasias Encefálicas/metabolismo , Neoplasias de la Mama/inmunología , Neoplasias de la Mama/metabolismo , Cetuximab , Doxorrubicina/administración & dosificación , Sistemas de Liberación de Medicamentos , Epirrubicina/administración & dosificación , Receptores ErbB/genética , Receptores ErbB/inmunología , Femenino , Glioblastoma/inmunología , Glioblastoma/metabolismo , Humanos , Fragmentos Fab de Inmunoglobulinas/inmunología , Ratones , Ratones Desnudos , Ratas , Ratas Sprague-Dawley , Transfección , Trasplante Heterólogo , Células Tumorales Cultivadas/efectos de los fármacos , Células Tumorales Cultivadas/metabolismo , Vinblastina/administración & dosificación , Vinblastina/análogos & derivados , VinorelbinaRESUMEN
Treatment of malignant gliomas represents one of the most formidable challenges in oncology. The combination of surgery, radiation, and chemotherapy yields median survivals of less than one year. Here we demonstrate the use of a minimally invasive surgical technique, convection-enhanced delivery (CED), for local administration of a novel nanoparticle liposome containing topotecan. CED of this liposomal topotecan (Ls-TPT) resulted in extended brain tissue retention (t1/2 = 1.5 days), whereas free topotecan was rapidly cleared (t1/2 = 0.1 days) after CED. The favorable pharmacokinetic profile of extended topotecan release for about seven days, along with biodistribution featuring perivascular accumulation of the nanoparticles, provided, in addition to the known topoisomerase I inhibition, an effective antiangiogenic therapy. In the rat intracranial U87MG tumor model, vascular targeting of Ls-TPT with CED was associated with reductions in laminin expression and vascular density compared to free topotecan or control treatments. A single CED treatment on day 7 showed that free topotecan conferred no survival benefit versus control. However, Ls-TPT produced a significant (P = 0.0002) survival benefit, with six of seven complete cures. Larger U87MG tumors, where CED of Ls-TPT on day 12 resulted in one of six cures, indicated the necessity to cover the entire tumor with the infused therapeutic agent. CED of Ls-TPT was also efficacious in the intracranial U251MG tumor model (P = 0.0005 versus control). We conclude that the combination of a novel nanoparticle Ls-TPT and CED administration was very effective in treating experimental brain tumors.
Asunto(s)
Neoplasias Encefálicas/tratamiento farmacológico , Convección , Sistemas de Liberación de Medicamentos/métodos , Glioma/tratamiento farmacológico , Topotecan/administración & dosificación , Ensayos Antitumor por Modelo de Xenoinjerto/métodos , Animales , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Glioma/patología , Humanos , Liposomas , Masculino , Ratas , Ratas DesnudasRESUMEN
Convection-enhanced delivery (CED) is a recently developed technique for local delivery of agents to a large volume of tissue in the central nervous system (CNS). We have previously reported that this technique can be applied to CNS delivery of nanoparticles including viruses and liposomes. In this paper, we describe the impact of key physical and chemical properties of infused molecules on the extent of CED-mediated delivery. For simple infusates, CED distribution was significantly increased if the infusate was more hydrophilic or had less tissue affinity. Encapsulation of tissue-affinitive molecules by neutral liposomes significantly increased their tissue distribution. The poorer brain distribution observed with cationic liposomes, due to their greater tissue affinity, was completely overcome by PEGylation, which provides steric stabilization and reduced surface charge. Finally, liposomal encapsulation of doxorubicin reduced its tissue affinity and substantially increased its distribution within brain tumor tissue. Taken together, the physical and chemical properties of drugs, small molecules and macromolecular carriers determine the tissue affinity of the infusate and strongly affect the distribution of locally applied agents. Thus, an increased and more predictable tissue distribution can be achieved by reducing the tissue affinity of the infusate using appropriately engineered liposomes or other nanoparticles.
Asunto(s)
Encéfalo/fisiología , Sistemas de Liberación de Medicamentos/instrumentación , Preparaciones Farmacéuticas/administración & dosificación , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacocinética , Antineoplásicos/uso terapéutico , Neoplasias Encefálicas/tratamiento farmacológico , Química Farmacéutica , Convección , Composición de Medicamentos , Electroquímica , Excipientes , Liposomas , Masculino , Nanoestructuras , Tamaño de la Partícula , Vehículos Farmacéuticos , Polietilenglicoles/química , Ratas , Ratas Sprague-Dawley , EstereoisomerismoRESUMEN
Liposomes loaded with Gadoteridol, in combination with convection-enhanced delivery (CED), offer an excellent option to monitor CNS delivery of therapeutic compounds with MRI. In previous studies, we investigated possible clinical applications of liposomes to the treatment of brain tumors. In this study, up to 700 microl of Gadoteridol/rhodamine-loaded liposomes were distributed in putamen, corona radiata and brainstem of non-human primates. Distribution was monitored by real-time MRI throughout infusion procedures and allowed accurate calculation of volume of distribution within anatomical structures. We found that different regions of the brain gave various volumes of distribution when infused with the same volume of liposome. Based on these findings, distinct distribution pathways within infused structures can be predicted. This work underlines the importance of monitoring drug delivery to CNS and enables accurate delivery of drug-loaded liposomes to specific brain regions with a standard MRI procedure. Findings presented in this manuscript may allow for modeling of parameters used for direct delivery of therapeutics into various regions of the brain.
Asunto(s)
Encéfalo/fisiología , Sistemas de Liberación de Medicamentos , Liposomas , Imagen por Resonancia Magnética/métodos , Animales , Encéfalo/anatomía & histología , Medios de Contraste , Excipientes , Colorantes Fluorescentes , Gadolinio , Compuestos Heterocíclicos/administración & dosificación , Macaca fascicularis , Masculino , Compuestos Organometálicos/administración & dosificación , RodaminasRESUMEN
AIM: We sought to evaluate nanoliposomal irinotecan as an intravenous treatment in an orthotopic brain tumor model. MATERIALS & METHODS: Nanoliposomal irinotecan was administered intravenously in the intracranial U87MG brain tumor model in mice, and irinotecan and SN-38 levels were analyzed in malignant and normal tissues. Therapy studies were performed in comparison to free irinotecan and control treatments. RESULTS: Tissue analysis demonstrated favorable properties for nanoliposomal irinotecan, including a 10.9-fold increase in tumor AUC for drug compared with free irinotecan and 35-fold selectivity for tumor versus normal tissue exposure. As a therapy for orthotopic brain tumors, nanoliposomal irinotecan showed a mean survival time of 54.2 versus 29.5 days for free irinotecan. A total of 33% of the animals receiving nanoliposomal irinotecan showed no residual tumor by study end compared with no survivors in the other groups. CONCLUSION: Nanoliposomal irinotecan administered systemically provides significant pharmacologic advantages and may be an efficacious therapy for brain tumors.
Asunto(s)
Antineoplásicos Fitogénicos/uso terapéutico , Neoplasias Encefálicas/tratamiento farmacológico , Camptotecina/análogos & derivados , Liposomas , Nanoestructuras , Animales , Antineoplásicos Fitogénicos/administración & dosificación , Antineoplásicos Fitogénicos/farmacocinética , Neoplasias Encefálicas/metabolismo , Camptotecina/administración & dosificación , Camptotecina/farmacocinética , Camptotecina/uso terapéutico , Irinotecán , RatasRESUMEN
AIM: The aim of this work is to evaluate combining targeting strategy and convection-enhanced delivery in brain tumor models by imaging quantum dot-immunoliposome hybrid nanoparticles. MATERIALS & METHODS: An EGF receptor-targeted, quantum dot-immunoliposome hybrid nanoparticle (QD-IL) was synthesized. In vitro uptake was measured by flow cytometry and intracellular localization was imaged by confocal microscopy. In the in vivo study, QD-ILs were delivered to intracranial xenografts via convection-enhanced delivery and fluorescence was monitored noninvasively in real-time. RESULTS: QD-ILs exhibited specific and efficient uptake in vitro and exhibited approximately 1.3- to 5.0-fold higher total fluorescence compared with nontargeted counterpart in intracranial brain tumor xenografts in vivo. CONCLUSION: QD-ILs serve as an effective imaging agent in vitro and in vivo, and the data suggest that ligand-directed liposomal nanoparticles in conjunction with convection-enhanced delivery may offer therapeutic benefits for glioblastoma treatment as a result of specific and efficient uptake by malignant cells.
Asunto(s)
Neoplasias Encefálicas/metabolismo , Encéfalo/patología , Sistemas de Liberación de Medicamentos , Receptores ErbB/metabolismo , Glioblastoma/metabolismo , Liposomas/metabolismo , Puntos Cuánticos/metabolismo , Animales , Encéfalo/metabolismo , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Convección , Femenino , Glioblastoma/patología , Humanos , Liposomas/análisis , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Puntos Cuánticos/análisisRESUMEN
Immunoliposomes provide a complementary, and in many instances advantageous, drug delivery strategy to antibody-drug conjugates. Their high carrying capacity of 20,000-150,000 drug molecules/liposome, allows for the use of a significantly broader range of moderate-to-high potency small molecule drugs when compared to the comparably few subnanomolar potency maytansinoid- and auristatin-based immunoconjugates. The multivalent display of 5-100 antibody fragments/liposome results in an avidity effect that can make use of even moderate affinity antibodies, as well as a cross-linking of cell surface receptors to induce the internalization required for intracellular drug release and subsequent activity. The underlying liposomal drug must be effectively engineered for long circulating pharmacokinetics and stable in vivo drug retention in order to allow for the drug to be efficiently delivered to the target tissue and take advantage of the site-specific bioavailability provided for by the targeting arm. In this chapter, we describe the rationale for engineering stable immunoliposome-based therapeutics, methods required for preparation of immunoliposomes, as well as for their physicochemical and in vivo characterization.
Asunto(s)
Antineoplásicos/metabolismo , Sistemas de Liberación de Medicamentos/métodos , Inmunoconjugados/metabolismo , Fragmentos de Inmunoglobulinas/metabolismo , Liposomas/metabolismo , Nanomedicina/métodos , Neoplasias/tratamiento farmacológico , Animales , Anticuerpos Monoclonales/metabolismo , Anticuerpos Monoclonales/farmacocinética , Afinidad de Anticuerpos , Antineoplásicos/farmacocinética , Composición de Medicamentos/métodos , Estabilidad de Medicamentos , Humanos , Inmunoconjugados/química , Inmunoconjugados/farmacocinética , Fragmentos de Inmunoglobulinas/química , Cinética , Lípidos/química , Liposomas/inmunología , Ratones , Neoplasias/inmunología , Neoplasias/metabolismo , Neoplasias/patología , Tamaño de la Partícula , Polietilenglicoles/química , Ingeniería de Proteínas/métodos , Ratas , Reactivos de Sulfhidrilo/químicaRESUMEN
Achieving effective treatment outcomes for patients with glioblastoma (GBM) has been impeded by many obstacles, including the pharmacokinetic limitations of antitumor agents, such as topotecan (TPT). Here, we demonstrate that intravenous administration of a novel nanoliposomal formulation of TPT (nLS-TPT) extends the survival of mice with intracranial GBM xenografts, relative to administration of free TPT, because of improved biodistribution and pharmacokinetics of the liposome-formulated drug. In 3 distinct orthotopic GBM models, 3 weeks of biweekly intravenous therapy with nLS-TPT was sufficient to delay tumor growth and significantly extend animal survival, compared with treatment with free TPT (P ≤ .03 for each tumor tested). Analysis of intracranial tumors showed increased activation of cleaved caspase-3 and increased DNA fragmentation, both indicators of apoptotic response to treatment with nLS-TPT. These results demonstrate that intravenous delivery of nLS-TPT is a promising strategy in the treatment of GBM and support clinical investigation of this therapeutic approach.
Asunto(s)
Neoplasias Encefálicas/tratamiento farmacológico , Sistemas de Liberación de Medicamentos , Glioblastoma/tratamiento farmacológico , Liposomas , Nanotecnología , Inhibidores de Topoisomerasa I/uso terapéutico , Topotecan/uso terapéutico , Animales , Neoplasias Encefálicas/mortalidad , Neoplasias Encefálicas/patología , Femenino , Glioblastoma/mortalidad , Glioblastoma/patología , Humanos , Técnicas para Inmunoenzimas , Mediciones Luminiscentes , Ratones , Ratones Desnudos , Tasa de Supervivencia , Distribución Tisular , Inhibidores de Topoisomerasa I/farmacocinética , Topotecan/farmacocinética , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Topotecan (TPT), a highly active anticancer camptothecin drug, would benefit from nanocarrier-mediated site-specific and intracellular delivery because of a labile lactone ring whose hydrolysis inactivates the drug, poor cellular uptake resulting from both lactone hydrolysis and a titratable phenol hydroxyl, and the schedule-dependency of its efficacy due to its mechanism of action. We have encapsulated topotecan in liposomes using transmembrane gradients of triethylammonium salts of polyphosphate (Pn) or sucroseoctasulfate (SOS). Circulation lifetimes were prolonged, and the rate of drug release in vivo depended on the drug load (T(1/2)=5.4 h vs. 11.2 h for 124 and 260 g TPT/mol PL, respectively) and the nature of intraliposomal drug complexing agent used to stabilize the nanoliposome formulation (T(1/2)=11.2 h vs. 27.3 h for Pn and SOS, respectively). Anti-EGFR and anti-HER2-immunoliposomal formulations dramatically increased uptake of topotecan compared to nontargeted nanoliposomal topotecan and poorly permeable free topotecan in receptor-overexpressing cancer cell lines, with a corresponding increase in cytotoxicity in multiple breast cancer cell lines and improved antitumor activity against HER2-overexpressing human breast cancer (BT474) xenografts. We conclude that stabilization of topotecan in nanoliposomes significantly improves the targetability and pharmacokinetic profile of topotecan, allowing for highly active formulations against solid tumors and immunotargeting to cancer-overexpressing cell surface receptors.
Asunto(s)
Antineoplásicos/química , Nanoestructuras/química , Topotecan/química , Animales , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacocinética , Antineoplásicos/uso terapéutico , Línea Celular Tumoral , Química Farmacéutica , Estabilidad de Medicamentos , Receptores ErbB/antagonistas & inhibidores , Femenino , Humanos , Liposomas , Ratones , Ratones Desnudos , Estructura Molecular , Neoplasias Experimentales/tratamiento farmacológico , Receptor ErbB-2/antagonistas & inhibidores , Factores de Tiempo , Topotecan/administración & dosificación , Topotecan/farmacocinética , Topotecan/uso terapéutico , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Canine spontaneous intracranial tumors bear striking similarities to their human tumor counterparts and have the potential to provide a large animal model system for more realistic validation of novel therapies typically developed in small rodent models. We used spontaneously occurring canine gliomas to investigate the use of convection-enhanced delivery (CED) of liposomal nanoparticles, containing topoisomerase inhibitor CPT-11. To facilitate visualization of intratumoral infusions by real-time magnetic resonance imaging (MRI), we included identically formulated liposomes loaded with Gadoteridol. Real-time MRI defined distribution of infusate within both tumor and normal brain tissues. The most important limiting factor for volume of distribution within tumor tissue was the leakage of infusate into ventricular or subarachnoid spaces. Decreased tumor volume, tumor necrosis, and modulation of tumor phenotype correlated with volume of distribution of infusate (Vd), infusion location, and leakage as determined by real-time MRI and histopathology. This study demonstrates the potential for canine spontaneous gliomas as a model system for the validation and development of novel therapeutic strategies for human brain tumors. Data obtained from infusions monitored in real time in a large, spontaneous tumor may provide information, allowing more accurate prediction and optimization of infusion parameters. Variability in Vd between tumors strongly suggests that real-time imaging should be an essential component of CED therapeutic trials to allow minimization of inappropriate infusions and accurate assessment of clinical outcomes.