RESUMEN
In this report, we present a series involving critically ill patients with known coronavirus disease (COVID-19) infection where a portable X-ray machine equipped with artificial intelligence (AI) software aided in the urgent radiographic diagnosis of pneumothorax. These cases demonstrate how real-world clinical employment of AI tools capable of analyzing and prioritizing studies in the radiologist's worklist can potentially lead to earlier detection of emergent findings like pneumothorax. The use of AI tools in this manner has the potential to both improve radiology workflow and add significant clinical value in managing critically ill patient populations, such as those with severe COVID-19 infection.
RESUMEN
In this article, we aim to highlight the utility of dual-energy computed tomography (DECT) in demonstrating imaging changes due to hypoxic pulmonary vasoconstriction (HPV). DECT allows detailed image reconstructions that have been shown to better characterize cardiothoracic pathologies, as compared to conventional CT techniques. DECT simultaneously detects two different X-ray energies, which enables generation of iodine density maps, virtual monoenergetic images, and effective atomic number maps (Zeff), among others. DECT has been shown to have utility in the assessment of benign versus malignant pulmonary nodules, pulmonary embolism, myocardial perfusion defects, and other conditions. Herein, we describe four cases of indeterminate pulmonary pathology when imaged with conventional CT in which subsequent use of DECT-derived image reconstructions demonstrated HPV as the underlying pathophysiological mechanism. The goal of this article is to understand the imaging appearance of HPV on DECT and discuss how HPV may mimic other causes of perfusion defects.
RESUMEN
Prior research has identified both the contribution that people make to nature and the contribution that nature makes to people (by enhancing wellbeing) - with clear conceptual models to describe the interactions. Prior research has also made a clear case for incorporating insights from multiple perspectives and knowledge systems when seeking to better understand this interactive system. What is lacking, is guidance on how to operationalise some of these ideas to provide bespoke advice to environmental managers. Arguably, we have an adequate, albeit imperfect, understanding of how to operationalise (measure, value and/or otherwise account for) some parts of the conceptual model. There is, for example, abundant literature that describes different ways of valuing Ecosystem services, and a growing body of literature that describes and quantifies the ecological benefits of various stewardship activities, which will subsequently also generate an indirect benefit to people (since improved ecological conditions will improve Ecosystem services). In comparison, we know relatively little about the way in which stewardship activities directly benefit people - and it is on this gap that our paper focuses. We partially fill that knowledge gap by first reaching out to and learning from some of Australia's First Nations People. Key learnings underscore the inter-connectedness of the system, and the need for resource managers to not only monitor the extent and condition of natural system but also the extent and condition of an inextricably connected human system, in addition to the human-nature interactions. We clearly identify ways in which those insights can be used to improve and extend accounting frameworks, such as SEEA Ecosystem Accounts developed by the United Nations that are often used by natural resource managers. In so doing, we generate new insights about Indigenous stewardship (Caring for Country) and methods of accounting for and monitoring stewardship activities. As such, our work provides a practical illustration of one way to populate conceptual models with 'real world' data that also incorporates different world views, to support decision makers for improved social and environmental outcomes.
Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Humanos , Recursos Naturales , Naciones UnidasRESUMEN
Functional outcome following traumatic brain injury (TBI) varies greatly, with approximately half of those who survive suffering long-term motor and cognitive deficits despite contemporary rehabilitation efforts. We have previously shown that deep brain stimulation (DBS) of the lateral cerebellar nucleus (LCN) enhances rehabilitation of motor deficits that result from brain injury. The objective of the present study was to evaluate the efficacy of LCN DBS on recovery from rodent TBI that uniquely models the injury location, chronicity and resultant cognitive symptoms observed in most human TBI patients. We used controlled cortical impact (CCI) to produce an injury that targeted the medial prefrontal cortex (mPFC-CCI) bilaterally, resulting in cognitive deficits. Unilateral LCN DBS electrode implantation was performed 6 weeks post-injury. Electrical stimulation started at week eight post-injury and continued for an additional 4 weeks. Cognition was evaluated using baited Y-maze, novel object recognition task and Barnes maze. Post-mortem analyses, including Western Blot and immunohistochemistry, were conducted to elucidate the cellular and molecular mechanisms of recovery. We found that mPFC-CCI produced significant cognitive deficits compared to pre-injury and naïve animals. Moreover, LCN DBS treatment significantly enhanced the long-term memory process and executive functions of applying strategy. Analyses of post-mortem tissues showed significantly greater expression of CaMKIIα, BDNF and p75NTR across perilesional cortex and higher expression of postsynaptic formations in LCN DBS-treated animals compared to untreated. Overall, these data suggest that LCN DBS is an effective treatment of cognitive deficits that result from TBI, possibly by activation of ascending, glutamatergic projections to thalamus and subsequent upregulation of thalamocortical activity that engages neuroplastic mechanisms for facilitation of functional re-organization. These results support a role for cerebellar output neuromodulation as a novel therapeutic approach to enhance rehabilitation for patients with chronic, post-TBI cognitive deficits that are unresponsive to traditional rehabilitative efforts.
Asunto(s)
Lesiones Traumáticas del Encéfalo , Lesiones Encefálicas , Estimulación Encefálica Profunda , Animales , Lesiones Traumáticas del Encéfalo/complicaciones , Lesiones Traumáticas del Encéfalo/terapia , Núcleos Cerebelosos/fisiología , Cognición , Estimulación Encefálica Profunda/métodos , RoedoresRESUMEN
While antibody-drug conjugates (ADCs) are advancing through clinical testing and receiving new marketing approvals, improvements to the technology continue to be developed in both academic and industrial laboratories. Among the key ADC attributes that can be improved upon with new technology are their biodistribution and pharmacokinetic properties. During the course of ADC development, it has become apparent that conjugation of drugs to the surface of a monoclonal antibody can alter its physicochemical characteristics in a manner that results in increased nonspecific interactions and more rapid elimination from plasma. Researchers in the field have typically relied upon in vivo studies in preclinical models to understand how a particular ADC chemistry will impact these biological characteristics. In previous work, we described how animal studies have revealed a relationship between ADC hydrophobicity, pharmacokinetics, and nonspecific hepatic clearance, particularly by sinusoidal endothelium and Kupffer cells. Here, we describe a fluorescence-based assay using cultured Kupffer cells to recapitulate the nonspecific interactions that lead to ADC clearance in an in vitro setting with the aim of developing a tool for predicting the pharmacokinetics of novel ADC designs. Output from this assay has demonstrated an excellent correlation with plasma clearance for a series of closely related ADCs bearing discrete PEG chains of varying length and has proven useful in interrogating the mechanism of the interactions between ADCs and Kupffer cells.
Asunto(s)
Diseño de Fármacos , Inmunoconjugados/administración & dosificación , Inmunoconjugados/farmacocinética , Macrófagos del Hígado/efectos de los fármacos , Macrófagos del Hígado/metabolismo , Animales , Anticuerpos Monoclonales/sangre , Anticuerpos Monoclonales/química , Médula Ósea/metabolismo , Técnicas de Cultivo de Célula/métodos , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Femenino , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Inmunoconjugados/sangre , Inmunoconjugados/química , Inyecciones Intravenosas , Hígado/metabolismo , Tasa de Depuración Metabólica , Ratas , Ratas Sprague-Dawley , Propiedades de Superficie/efectos de los fármacos , Distribución TisularRESUMEN
Native size-exclusion chromatography-mass spectrometry (nSEC-MS) is an analytical methodology that is appropriate for accurately quantitating the drug-to-antibody ratio (DAR) on a wide variety of interchain cysteine-linked antibody-drug conjugates (ADCs), irrespective of chemotype. In the current preclinical environment, novel ADCs conjugated with unique drug-linkers need to progress toward the clinic as quickly as possible. Platform analytical approaches can reduce time-to-clinic because key process development and optimization activities can be decoupled from the development of bespoke, molecule-specific analytical methods. In this work, we assessed the potential of nSEC-MS as a platformable, quantitative DAR method. The nSEC-MS method was evaluated according to performance characteristics and parameters described in the ICH guideline Validation of Analytical Procedures: Text and Methodology Q2(R1). In order to comprehensively assess the accuracy and bias of nSEC-MS DAR quantitation, ADCs were generated using three different drug-linker chemotypes with DARs ranging from 2 to 8. These molecules were tested by hydrophobic interaction chromatography (HIC) and nSEC-MS, and DARs obtained from both methods were compared to assess the degree to which nSEC-MS quantitation aligned with the HIC release assay. Our results indicated that there is no bias introduced by nSEC-MS quantitation of DAR and that SEC-MS data can be bridged to HIC data without the need for a correction factor or offset. nSEC-MS was also found to be suitable for unbiased DAR quantitation in the other ADC chemotypes that were evaluated. Based on the totality of our work, we conclude that, used as intended, nSEC-MS is well suited for quantitating DAR on a variety of interchain cysteine-linked ADCs in an accurate, unbiased manner.
Asunto(s)
Cromatografía en Gel/métodos , Inmunoconjugados/química , Espectrometría de Masas/métodos , Animales , Células CHO , Cricetulus , Estudios de Factibilidad , Humanos , Interacciones Hidrofóbicas e HidrofílicasRESUMEN
Undergraduate research experiences (UREs) have the potential to benefit undergraduates and longer UREs have been shown to lead to greater benefits for students. However, no studies have examined what causes students to stay in or consider leaving their UREs. In this study, we examined what factors cause students to stay in their UREs, what factors cause students to consider leaving their UREs, and what factors cause students to leave their UREs. We sampled from 25 research-intensive (R1) public universities across the United States and surveyed 768 life sciences undergraduates who were currently participating in or had previously participated in a URE. Students answered closed-ended and open-ended questions about factors that they perceived influenced their persistence in UREs. We used logistic regression to explore to what extent student demographics predicted what factors influenced students to stay in or consider leaving their UREs. We applied open-coding methods to probe the student-reported reasons why students chose to stay in and leave their UREs. Fifty percent of survey respondents considered leaving their URE, and 53.1% of those students actually left their URE. Students who reported having a positive lab environment and students who indicated enjoying their everyday research tasks were more likely to not consider leaving their UREs. In contrast, students who reported a negative lab environment or that they were not gaining important knowledge or skills were more likely to leave their UREs. Further, we identified that gender, race/ethnicity, college generation status, and GPA predicted which factors influenced students' decisions to persist in their UREs. This research provides important insight into how research mentors can create UREs that undergraduates are willing and able to participate in for as long as possible.
Asunto(s)
Disciplinas de las Ciencias Biológicas/educación , Selección de Profesión , Investigación/educación , Estudiantes/psicología , Femenino , Humanos , Masculino , Encuestas y Cuestionarios , UniversidadesRESUMEN
To provide a better understanding of the pharmacokinetics-pharmacodynamics relationships of antibody-based drugs, we analyzed several chimeric and humanized monoclonal antibodies or antibody-drug conjugates (ADC) for PK and efficacy among four strains of mice. Notably, antibodies and ADCs displayed a dose-dependent drug disposition profile in the plasma of NSG mice. The increased clearance rate in NSG mice resulted in the reduction of antitumor activity of ADCs. Furthermore, we identified that the abnormal clearance was mediated by Fc-FcγR interaction by comparing antibodies that lack FcγR binding capacity. We also found a high percentage of FcγR-expressing macrophages in the bone marrow, spleen, and liver of NSG mice, which may be responsible for the abnormal distribution of antibodies. Overall, these findings suggest that preclinical evaluation of efficacy and pharmacokinetics of antibodies and ADCs need to consider mouse strain-induced variations.
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Antineoplásicos/uso terapéutico , Inmunoconjugados/uso terapéutico , Linfoma Anaplásico de Células Grandes/tratamiento farmacológico , Receptores de IgG/metabolismo , Animales , Anticuerpos Monoclonales/metabolismo , Antineoplásicos/metabolismo , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Femenino , Semivida , Humanos , Inmunoconjugados/metabolismo , Antígeno Ki-1/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos NOD , Ratones Desnudos , Ratones SCID , Células Mieloides/inmunología , Células Mieloides/metabolismo , Glutamato de Sodio/farmacología , Resultado del Tratamiento , Carga Tumoral , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The emergence of antibody-drug conjugates (ADC), such as brentuximab vedotin and ado-trastuzumab emtansine, has led to increased efforts to identify new payloads and develop improved drug-linker technologies. Most antibody payloads impart significant hydrophobicity to the ADC, resulting in accelerated plasma clearance and suboptimal in vivo activity, particularly for conjugates with high drug-to-antibody ratios (DAR). We recently reported on the incorporation of a discrete PEG24 polymer as a side chain in a ß-glucuronidase-cleavable monomethylauristatin E (MMAE) linker to provide homogeneous DAR 8 conjugates with decreased plasma clearance and increased antitumor activity in xenograft models relative to a non-PEGylated control. In this work, we optimized the drug-linker by minimizing the size of the PEG side chain and incorporating a self-stabilizing maleimide to prevent payload de-conjugation in vivo Multiple PEG-glucuronide-MMAE linkers were prepared with PEG size up to 24 ethylene oxide units, and homogeneous DAR 8 ADCs were evaluated. A clear relationship was observed between PEG length and conjugate pharmacology when tested in vivo Longer PEG chains resulted in slower clearance, with a threshold length of PEG8 beyond which clearance was not impacted. Conjugates bearing PEG of sufficient length to minimize plasma clearance provided a wider therapeutic window relative to faster clearing conjugates bearing shorter PEGs. A lead PEGylated glucuronide-MMAE linker was identified incorporating a self-stabilizing maleimide and a PEG12 side chain emerged from these efforts, enabling highly potent, homogeneous DAR 8 conjugates and is under consideration for future ADC programs. Mol Cancer Ther; 16(1); 116-23. ©2016 AACR.
Asunto(s)
Antineoplásicos/farmacología , Inmunoconjugados/farmacología , Oligopéptidos , Polietilenglicoles , Animales , Anticuerpos Monoclonales/química , Antineoplásicos/administración & dosificación , Antineoplásicos/química , Antineoplásicos/farmacocinética , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Estabilidad de Medicamentos , Humanos , Inmunoconjugados/administración & dosificación , Inmunoconjugados/química , Inmunoconjugados/farmacocinética , Maleimidas/química , Maleimidas/farmacología , Ratones , Estructura Molecular , Oligopéptidos/química , Polietilenglicoles/química , Análisis de Supervivencia , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
A strategy for the preparation of homogeneous antibody-drug conjugates (ADCs) containing multiple payloads has been developed. This approach utilizes sequential unmasking of cysteine residues with orthogonal protection to enable site-specific conjugation of each drug. In addition, because the approach utilizes conjugation to native antibody cysteine residues, it is widely applicable and enables high drug loading for improved ADC potency. To highlight the benefits of ADC dual drug delivery, this strategy was applied to the preparation of ADCs containing two classes of auristatin drug-linkers that have differing physiochemical properties and exert complementary anti-cancer activities. Dual-auristatin ADCs imparted activity in cell line and xenograft models that are refractory to ADCs comprised of the individual auristatin components. This work presents a facile method for construction of potent dual-drug ADCs and demonstrates how delivery of multiple cytotoxic warheads can lead to improved ADC activities. Lastly, we anticipate that the conditions utilized herein for orthogonal cysteine unmasking are not restricted to ADCs and can be broadly utilized for site-specific protein modification.
Asunto(s)
Aminobenzoatos/química , Anticuerpos Monoclonales/química , Antineoplásicos/química , Cisteína/química , Inmunoconjugados/química , Oligopéptidos/química , Sistemas de Liberación de Medicamentos , Conformación MolecularRESUMEN
A quaternary ammonium-based drug-linker has been developed to expand the scope of antibody-drug conjugate (ADC) payloads to include tertiary amines, a functional group commonly present in biologically active compounds. The linker strategy was exemplified with a ß-glucuronidase-cleavable auristatin E construct. The drug-linker was found to efficiently release free auristatin E (AE) in the presence of ß-glucuronidase and provide ADCs that were highly stable in plasma. Anti-CD30 conjugates comprised of the glucuronide-AE linker were potent and immunologically specific in vitro and in vivo, displaying pharmacologic properties comparable with a carbamate-linked glucuronide-monomethylauristatin E control. The quaternary ammonium linker was then applied to a tubulysin antimitotic drug that contained an N-terminal tertiary amine that was important for activity. A glucuronide-tubulysin quaternary ammonium linker was synthesized and evaluated as an ADC payload, in which the resulting conjugates were found to be potent and immunologically specific in vitro, and displayed a high level of activity in a Hodgkin lymphoma xenograft. Furthermore, the results were superior to those obtained with a related tubulysin derivative containing a secondary amine N-terminus for conjugation using previously known linker technology. The quaternary ammonium linker represents a significant advance in linker technology, enabling stable conjugation of payloads with tertiary amine residues. Mol Cancer Ther; 15(5); 938-45. ©2016 AACR.
Asunto(s)
Compuestos de Amonio/química , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/farmacología , Inmunoconjugados/química , Inmunoconjugados/farmacología , Animales , Anticuerpos Monoclonales/farmacocinética , Línea Celular Tumoral , Modelos Animales de Enfermedad , Liberación de Fármacos , Estabilidad de Medicamentos , Humanos , Inmunoconjugados/farmacocinética , Cinética , Ratones , Estructura Molecular , Unión Proteica , Ratas , Tubulina (Proteína) , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
BACKGROUND: Surgical site infection is routinely cited as the most common complication following orthopedic foot and ankle surgery. Our institution uses 4% chlorhexidine gluconate followed by 70% isopropyl alcohol to reduce skin bacterial loads prior to surgery. These solutions have potential synergistic qualities to prevent a postoperative infection. The purpose of this study was to determine if the order of these solutions has a significant effect on the residual bacterial pathogens load following operative site preparation for foot and ankle surgery, as evidenced by positive culture swabs. METHODS: A total of 95 consecutive patients, undergoing surgery of the foot and ankle with a single surgeon, were prospectively randomized to 1 of 2 operative preparation groups: isopropyl alcohol (IPA) group, whose operative site preparation consisted of a 4% chlorhexidine application followed by alcohol rinse (49 patients), and chlorhexidine gluconate (CHG) group, which had 46 patients undergo operative site preparation using alcohol followed by chlorhexidine. A total of 4 aerobic culture specimens were obtained from the third web space of the operative foot on each patient: (1) prior to operative site preparation, (2) after the prep was completed, (3) after completion of the procedure, and (4) after the incision was closed. Each patient was then followed for 6 months postoperatively to monitor the operative site. Medical comorbidities were also analyzed. RESULTS: The average time for IPA procedures was 52 minutes vs 54 for CHG (ns). There was no difference between groups with respect to diabetes, tobacco use, obesity, race, or immunosuppression. Both groups had 100% bacterial growth from specimens obtained prior to operative site preparation (P > .05). For all postpreparation swabs, 19.0% (28/147) of the IPA cultures were positive compared to 10.9% (15/138) from the CHG group cultures (P = .07). The amount of patients with positive culture results favored the CHG group at each collection point: 6.5% (3/46) versus 25% (12/49) after draping (P = .02); 15% (7/46) versus 33% (16/49) after completion of the surgery (P = .05); and 20% (9/46) versus 35% (17/49) after skin closure (P = .07). One operative site infection was seen in the first 30 days following surgery for each treatment group, each treated with oral antibiotics. No additional skin or wound complications were encountered during the 6-month study follow-up. CONCLUSION: Postoperative infection rates following foot and ankle orthopedic surgery was low. Both chlorhexidine and isopropyl alcohol solutions were effective methods in reducing operative site bacterial colonization when combined. In this study, applying isopropyl alcohol solution followed by the chlorhexidine solution was more effective in reducing positive bacterial cultures taken after operative site preparation. No difference in clinical wound infection rate was seen. LEVEL OF EVIDENCE: Level I, prospective randomized study.
Asunto(s)
2-Propanol/administración & dosificación , Antiinfecciosos Locales/administración & dosificación , Clorhexidina/análogos & derivados , Pie/cirugía , Procedimientos Ortopédicos , Infección de la Herida Quirúrgica/prevención & control , Adulto , Tobillo/cirugía , Bacterias/aislamiento & purificación , Clorhexidina/administración & dosificación , Esquema de Medicación , Quimioterapia Combinada , Femenino , Pie/microbiología , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Cuidados Preoperatorios/métodos , Estudios Prospectivos , Piel/microbiologíaRESUMEN
The in vitro potency of antibody-drug conjugates (ADCs) increases with the drug-to-antibody ratio (DAR); however, ADC plasma clearance also increases with DAR, reducing exposure and in vivo efficacy. Here we show that accelerated clearance arises from ADC hydrophobicity, which can be modulated through drug-linker design. We exemplify this using hydrophilic auristatin drug linkers and PEGylated ADCs that yield uniform, high-DAR ADCs with superior in vivo performance.
Asunto(s)
Química Farmacéutica , Inmunoconjugados , Preparaciones Farmacéuticas , Animales , Línea Celular , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Inmunoconjugados/química , Inmunoconjugados/farmacocinética , Ratones , Ratones SCID , Modelos Químicos , Modelos Moleculares , Preparaciones Farmacéuticas/químicaRESUMEN
BACKGROUND: Acute septic arthritis in a native joint may require more than one surgical debridement to eradicate the infection. Our objectives were to determine the prevalence of failure of a single surgical debridement for acute septic arthritis, to identify risk factors for failure of a single debridement, and to develop a prognostic probability algorithm to predict failure of a single surgical debridement for acute septic arthritis in adults. METHODS: We collected initial laboratory and medical comorbidity data of 128 adults (132 native joints) with acute septic arthritis who underwent at least one surgical debridement at our institution between 2000 and 2011. Univariate and logistic regression analyses were used to identify potential risk factors for failure of a single surgical debridement. Stepwise variable selection was used to develop a prediction model and identify probabilities of failure of a single surgical debridement. RESULTS: Of the 128 patients (132 affected joints) who underwent surgical debridement for acute septic arthritis, forty-nine (38%) of the patients (fifty joints) experienced failure of a single debridement and required at least two debridements (range, two to four debridements). Staphylococcus aureus was the most common bacterial isolate (in sixty, or 45%, of the 132 joints). Logistic regression analysis identified five independent clinical predictors for failure of a single surgical debridement: a history of inflammatory arthropathy (odds ratio [OR], 7.3; 95% confidence interval [CI], 2.4 to 22.6; p < 0.001), the involvement of a large joint (knee, shoulder, or hip) (OR, 7.0; 95% CI, 1.2 to 37.5; p = 0.02), a synovial-fluid nucleated cell count of >85.0 x 10(9) cells/L (OR, 4.7; 95% CI, 1.8 to 17.7; p = 0.002), S. aureus as the bacterial isolate (OR, 4.6; 95% CI, 1.8 to 11.9; p = 0.002), and a history of diabetes (OR, 2.6; 95% CI, 1.1 to 6.2; p = 0.04). CONCLUSIONS: Most (62%) of the septic joints were managed effectively with a single surgical debridement. Adults with a history of inflammatory arthropathy, involvement of a large joint, a synovial-fluid nucleated cell count of >85.0 x 10(9) cells/L, an infection with S. aureus, or a history of diabetes had a higher risk of failure of a single surgical debridement for acute septic arthritis and requiring additional surgical debridement(s).
Asunto(s)
Artritis Infecciosa/cirugía , Desbridamiento , Adulto , Anciano , Algoritmos , Articulación del Tobillo/cirugía , Artritis Infecciosa/microbiología , Artroscopía , Desbridamiento/estadística & datos numéricos , Femenino , Humanos , Articulación de la Rodilla/cirugía , Modelos Logísticos , Masculino , Persona de Mediana Edad , Pronóstico , Factores de Riesgo , Articulación del Hombro/cirugía , Infecciones Estafilocócicas/cirugía , Insuficiencia del TratamientoRESUMEN
In this article, we describe a novel antibody-drug conjugate (ADC; SGN-LIV1A), targeting the zinc transporter LIV-1 (SLC39A6) for the treatment of metastatic breast cancer. LIV-1 was previously known to be expressed by estrogen receptor-positive breast cancers. In this study, we show that LIV-1 expression is maintained after hormonal therapy in primary and metastatic sites and is also upregulated in triple-negative breast cancers. In addition to breast cancer, other indications showing LIV-1 expression include melanoma, prostate, ovarian, and uterine cancer. SGN-LIV1A consists of a humanized antibody conjugated through a proteolytically cleavable linker to monomethyl auristatin E, a potent microtubule-disrupting agent. When bound to surface-expressed LIV-1 on immortalized cell lines, this ADC is internalized and traffics to the lysozome. SGN-LIV1A displays specific in vitro cytotoxic activity against LIV-1-expressing cancer cells. In vitro results are recapitulated in vivo where antitumor activity is demonstrated in tumor models of breast and cervical cancer lineages. These results support the clinical evaluation of SGN-LIV1A as a novel therapeutic agent for patients with LIV-1-expressing cancer.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Proteínas de Transporte de Catión/antagonistas & inhibidores , Inmunoconjugados/farmacología , Proteínas de Neoplasias/antagonistas & inhibidores , Animales , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales Humanizados/administración & dosificación , Anticuerpos Monoclonales Humanizados/farmacología , Afinidad de Anticuerpos , Antineoplásicos/administración & dosificación , Antineoplásicos Hormonales/farmacología , Antineoplásicos Hormonales/uso terapéutico , Neoplasias de la Mama/tratamiento farmacológico , Proteínas de Transporte de Catión/genética , Proteínas de Transporte de Catión/metabolismo , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Femenino , Expresión Génica , Humanos , Inmunoconjugados/administración & dosificación , Inmunofenotipificación , Lisosomas/metabolismo , Células MCF-7 , Microtúbulos/metabolismo , Metástasis de la Neoplasia , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Many antibody-drug conjugates (ADCs) are unstable in vivo because they are formed from maleimide-containing components conjugated to reactive thiols. These thiosuccinimide linkages undergo two competing reactions in plasma: elimination of the maleimide through a retro-Michael reaction, which results in loss of drug-linker from the ADC, and hydrolysis of the thiosuccinimide ring, which results in a derivative that is resistant to the elimination reaction. In an effort to create linker technologies with improved stability characteristics, we used diaminopropionic acid (DPR) to prepare a drug-linker incorporating a basic amino group adjacent to the maleimide, positioned to provide intramolecular catalysis of thiosuccinimide ring hydrolysis. This basic group induces the thiosuccinimide to undergo rapid hydrolysis at neutral pH and room temperature. Once hydrolyzed, the drug-linker is no longer subject to maleimide elimination reactions, preventing nonspecific deconjugation. In vivo studies demonstrate that the increased stability characteristics can lead to improved ADC antitumor activity and reduced neutropenia.
Asunto(s)
Anticuerpos/química , Antineoplásicos/química , Excipientes/química , Inmunoconjugados/química , Maleimidas/química , Animales , Antineoplásicos/farmacología , Proliferación Celular/efectos de los fármacos , Femenino , Humanos , Concentración de Iones de Hidrógeno , Hidrólisis , Inmunoconjugados/farmacología , Ratones , Ratones SCID , Plasma , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Towards the development of a methicillin-resistant Staphylococcus aureus (MRSA) vaccine we evaluated a neutralizing anti-glucosaminidase (Gmd) monoclonal antibody (1C11) in a murine model of implant-associated osteomyelitis, and compared its effects on LAC USA300 MRSA versus a placebo and a Gmd-deficient isogenic strain (ΔGmd). 1C11 significantly reduced infection severity, as determined by bioluminescent imaging of bacteria, micro-CT assessment of osteolysis, and histomorphometry of abscess numbers (p < 0.05). Histology also revealed infiltrating macrophages, and the complete lack of staphylococcal abscess communities (SAC), in marrow abscesses of 1C11 treated mice. In vitro, 1C11 had no direct effects on proliferation, but electron microscopy demonstrated that 1C11 treatment phenocopies ΔGmd defects in binary fission. Moreover, addition of 1C11 to MRSA cultures induced the formation of large bacterial aggregates (megaclusters) that sedimented out of solution, which was not observed in ΔGmd cultures or 1C11 treated cultures of a protein A-deficient strain (ΔSpa), suggesting that the combined effects of Gmd inhibition and antibody-mediated agglutination are required. Finally, we demonstrated that macrophage opsonophagocytosis of MRSA and megaclusters is significantly increased by 1C11 (p < 0.01). Collectively, these results suggest that the primary mechanism of anti-Gmd humoral immunity against MRSA osteomyelitis is macrophage invasion of Staphylococcal abscess communities (SAC) and opsonophagocytosis of megaclusters. .
Asunto(s)
Anticuerpos Monoclonales/administración & dosificación , Hexosaminidasas/inmunología , Osteomielitis/prevención & control , Fagocitosis/inmunología , Infecciones Relacionadas con Prótesis/prevención & control , Infecciones Estafilocócicas/prevención & control , Animales , Proliferación Celular/efectos de los fármacos , Femenino , Inmunización Pasiva , Staphylococcus aureus Resistente a Meticilina/genética , Staphylococcus aureus Resistente a Meticilina/patogenicidad , Ratones , Ratones Endogámicos BALB C , Proteínas Opsoninas/toxicidad , Osteomielitis/microbiología , Infecciones Relacionadas con Prótesis/microbiología , Infecciones Estafilocócicas/microbiologíaRESUMEN
BACKGROUND: Staphylococcus aureus infections remain a major complication of orthopaedic surgery. Although serum C-reactive protein is useful for diagnosis, there are no specific tests for host immunity that can assess a patient's risk for serious infection. On the basis of the identification of glucosaminidase as a potentially protective antigen in animal models, we tested the hypotheses that anti-glucosaminidase IgG (immunoglobulin G) levels vary in sera of mice and orthopaedic patients with Staphylococcus aureus infections and that physical and neutralizing titers correlate. METHODS: In vitro ELISAs (enzyme-linked immunosorbent assays) were developed to quantify binding (physical) and enzyme-neutralizing (functional) anti-glucosaminidase IgG titers. The assays were validated with use of sera from naive, Staphylococcus aureus-challenged, and glucosaminidase-immunized mice. The physical, functional, and isotype titers of anti-glucosaminidase IgG were measured in sera from twenty-four patients with a confirmed Staphylococcus aureus infection following orthopaedic surgery and in sera from twenty noninfected patients. The specificity of the anti-glucosaminidase assay was evaluated by means of linear regression and receiver-operator characteristic curve analysis. RESULTS: In mice, the analytic range of the physical titer assay for anti-glucosaminidase IgG was determined to be 1 ng/mL to 1 µg/mL, and physical titers correlated with functional titers (p < 0.002). Although all patients had measurable anti-glucosaminidase IgG, the physical titers in the infected patients were significantly higher by a factor of two compared with those in the healthy controls (p = 0.015). The physical titers were significantly correlated with the functional titers (p < 0.0001). Receiver-operator characteristic curve analysis demonstrated a diagnostic specificity of 0.72 (p = 0.014) for the assay. The anti-glucosaminidase titer in almost every patient was dominated by the IgG1 isotype. CONCLUSIONS: Humoral immunity against glucosaminidase varied in mammals with Staphylococcus aureus osteomyelitis. Anti-glucosaminidase titers in sera were a potential biomarker of infection and have the potential to assess the quality of host immunity against Staphylococcus aureus. CLINICAL RELEVANCE: Staphylococcus aureus infections can be challenging to diagnose, and there is no diagnostic test for host immunity. We demonstrated a cost-effective assay for determining the anti-glucosaminidase titer, which can be readily combined with conventional serology to improve diagnosis and to assess host immunity against Staphylococcus aureus.
Asunto(s)
Hexosaminidasas/antagonistas & inhibidores , Hexosaminidasas/inmunología , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Infecciones Estafilocócicas/inmunología , Staphylococcus aureus , Animales , Artroplastia de Reemplazo , Biomarcadores/sangre , Femenino , Fracturas Óseas/complicaciones , Fracturas Óseas/microbiología , Fracturas Óseas/cirugía , Humanos , Artropatías/complicaciones , Artropatías/microbiología , Artropatías/cirugía , Ratones , Ratones Endogámicos BALB C , Infecciones Estafilocócicas/complicacionesRESUMEN
A highly cytotoxic DNA cross-linking pyrrolobenzodiazepine (PBD) dimer with a valine-alanine dipeptide linker was conjugated to the anti-CD70 h1F6 mAb either through endogenous interchain cysteines or, site-specifically, through engineered cysteines at position 239 of the heavy chains. The h1F6239C-PBD conjugation strategy proved to be superior to interchain cysteine conjugation, affording an antibody-drug conjugate (ADC) with high uniformity in drug-loading and low levels of aggregation. In vitro cytotoxicity experiments demonstrated that the h1F6239C-PBD was potent and immunologically specific on CD70-positive renal cell carcinoma (RCC) and non-Hodgkin lymphoma (NHL) cell lines. The conjugate was resistant to drug loss in plasma and in circulation, and had a pharmacokinetic profile closely matching that of the parental h1F6239C antibody capped with N-ethylmaleimide (NEM). Evaluation in CD70-positive RCC and NHL mouse xenograft models showed pronounced antitumor activities at single or weekly doses as low as 0.1 mg/kg of ADC. The ADC was tolerated at 2.5 mg/kg. These results demonstrate that PBDs can be effectively used for antibody-targeted therapy.