Publications by authors named "Anne H Schmieder"

33 Publications

Nanotherapy delivery of c-myc inhibitor targets Protumor Macrophages and preserves Antitumor Macrophages in Breast Cancer.

Theranostics 2020 12;10(17):7510-7526. Epub 2020 Jun 12.

Department of Medicine, Division of Molecular Oncology, Washington University School of Medicine, St. Louis, MO 63110, USA.

Tumor-associated macrophages (TAMs) enhance tumor growth in mice and are correlated with a worse prognosis for breast cancer patients. While early therapies sought to deplete all macrophages, current therapeutics aim to reprogram pro-tumor macrophages (M2) and preserve those necessary for anti-tumor immune responses (M1). Recent studies have shown that c-MYC (MYC) is induced in M2 macrophages and where it regulates the expression of tumor-promoting genes. In a myeloid lineage MYC KO mouse model, MYC had important roles in macrophage maturation and function leading to reduced tumor growth. We therefore hypothesized that targeted delivery of a MYC inhibitor to established M2 TAMs could reduce polarization toward an M2 phenotype in breast cancer models. In this study, we developed a MYC inhibitor prodrug (MI3-PD) for encapsulation within perfluorocarbon nanoparticles, which can deliver drugs directly to the cytosol of the target cell through a phagocytosis independent mechanism. We have previously shown that M2-like TAMs express significant levels of the vitronectin receptor, integrin β3, and targeting and therapeutic potential was evaluated using αvβ3 integrin targeted rhodamine-labeled nanoparticles (NP) or integrin αvβ3-MI3-PD nanoparticles. We observed that rhodamine, delivered by αvβ3-rhodamine NP, was incorporated into M2 tumor promoting macrophages through both phagocytosis-independent and dependent mechanisms, while NP uptake in tumor suppressing M1 macrophages was almost exclusively through phagocytosis. In a mouse model of breast cancer (4T1-GFP-FL), M2-like TAMs were significantly reduced with αvβ3-MI3-PD NP treatment. To validate this effect was independent of drug delivery to tumor cells and was specific to the MYC inhibitor, mice with integrin β3 knock out tumors (PyMT-Bo1 β3KO) were treated with αvβ3-NP or αvβ3-MI3-PD NP. M2 macrophages were significantly reduced with αvβ3-MI3-PD nanoparticle therapy but not αvβ3-NP treatment. These data suggest αvβ3-NP-mediated drug delivery of a c-MYC inhibitor can reduce protumor M2-like macrophages while preserving antitumor M1-like macrophages in breast cancer.
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http://dx.doi.org/10.7150/thno.44523DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359087PMC
June 2020

Cellular Trafficking of Sn-2 Phosphatidylcholine Prodrugs Studied with Fluorescence Lifetime Imaging and Super-resolution Microscopy.

Precis Nanomed 2018 Jul 30;1(2):128-145. Epub 2018 Jun 30.

Department of Biomedical Engineering, Washington University in St. Louis, MO 63130, USA.

While the efficacy of Sn-2 phosphatidylcholine prodrugs incorporated into targeted, non-pegylated lipid-encapsulated nanoparticles was demonstrated in prior preclinical studies, the microscopic details of cell prodrug internalization and trafficking events are unknown. Classic fluorescence microscopy, fluorescence lifetime imaging microscopy, and single-molecule super-resolution microscopy were used to investigate the cellular handling of doxorubicin-prodrug and AlexaFluor™-488-prodrug. Sn-2 phosphatidylcholine prodrugs delivered by hemifusion of nanoparticle and cell phospholipid membranes functioned as phosphatidylcholine mimics, circumventing the challenges of endosome sequestration and release. Phosphatidylcholine prodrugs in the outer cell membrane leaflet translocated to the inner membrane leaflet by ATP-dependent and ATP-independent mechanisms and distributed broadly within the cytosolic membranes over the next 12 h. A portion of the phosphatidylcholine prodrug populated vesicle membranes trafficked to the perinuclear Golgi/ER region, where the drug was enzymatically liberated and activated. Native doxorubicin entered the cells, passed rapidly to the nucleus, and bound to dsDNA, whereas DOX was first enzymatically liberated from DOX-prodrug within the cytosol, particularly in the perinuclear region, before binding nuclear dsDNA. Much of DOX-prodrug was initially retained within intracellular membranes. anti-proliferation effectiveness of the two drug delivery approaches was equivalent at 48 h, suggesting that residual intracellular DOX-prodrug may constitute a slow-release drug reservoir that enhances effectiveness. We have demonstrated that Sn-2 phosphatidylcholine prodrugs function as phosphatidylcholine mimics following reported pathways of phosphatidylcholine distribution and metabolism. Drug complexed to the Sn-2 fatty acid is enzymatically liberated and reactivated over many hours, which may enhance efficacy overtime.
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http://dx.doi.org/10.33218/prnano1(2).180724.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6597004PMC
July 2018

Diagnosis of LVAD Thrombus using a High-Avidity Fibrin-Specific Tc Probe.

Theranostics 2018 2;8(4):1168-1179. Epub 2018 Feb 2.

Division of Cardiology, Washington University School of Medicine, St. Louis, MO.

Treatment of advanced heart failure with implantable LVADs is increasing, driven by profound unmet patient need despite potential serious complications: bleeding, infection, and thrombus. The experimental objective was to develop a sensitive imaging approach to assess early thrombus accumulation in LVADs under operational high flow and high shear rates. : A monomeric bifunctional ligand with a fibrin-specific peptide, a short spacer, and Tc chelating amino acid sequence (F1A) was developed and compared to its tetrameric PEG analogue (F4A). Tc attenuation by LVAD titanium (1 mm) was 23%. Tc-F1A affinity to fibrin was K ~10 µM, whereas, the bound Tc-F4A probe was not displaced by F1A (120,000:1). Human plasma interfered with Tc-F1A binding to fibrin clot (p<0.05) in vitro, whereas, Tc-F4A targeting was unaffected. The pharmacokinetic half-life of Tc-F4A was 28% faster (124±41 min) than Tc-F1A (176±26 min) with both being bioeliminated through the urinary system with negligible liver or spleen biodistribution. In mice with carotid thrombus, Tc-F4A binding to the injured carotid was much greater (16.3±3.3 %ID/g, p=0.01) than that measured with an irrelevant negative control, Tc-I4A (3.4±1.6 %ID/g). In an LVAD mock flow-loop (1:1, PBS:human plasma:heparin) operating at maximal flow rate, Tc-F4A bound well to phantom clots in 2 min (p<0.05), whereas Tc-F1A had negligible targeting. Excised LVADs from patients undergoing pump exchange or heart transplant were rewired, studied in the mock flow loop, and found to have spatially variable fibrin accumulations in the inlet and outlet cannulas and bearings. Tc-F4A is a high-avidity prototype probe for characterizing thrombus in LVADs that is anticipated to help optimize anticoagulation, reduce thromboembolic events, and minimize pump exchange.
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http://dx.doi.org/10.7150/thno.20271DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5817118PMC
January 2019

Local Intratracheal Delivery of Perfluorocarbon Nanoparticles to Lung Cancer Demonstrated with Magnetic Resonance Multimodal Imaging.

Theranostics 2018 1;8(2):563-574. Epub 2018 Jan 1.

Molecular Imaging Research Center (MIRC), Harbin Medical University, Harbin, Heilongjiang, China 2.TOF-PET/CT/MR center, The Fourth Hospital of Harbin Medical University, Harbin, Heilongjiang, China.

Eighty percent of lung cancers originate as subtle premalignant changes in the airway mucosal epithelial layer of bronchi and alveoli, which evolve and penetrate deeper into the parenchyma. Liquid-ventilation, with perfluorocarbons (PFC) was first demonstrated in rodents in 1966 then subsequently applied as lipid-encapsulated PFC emulsions to improve pulmonary function in neonatal infants suffering with respiratory distress syndrome in 1996. Subsequently, PFC nanoparticles (NP) were extensively studied as intravenous (IV) vascular-constrained nanotechnologies for diagnostic imaging and targeted drug delivery applications. This proof-of-concept study compared intratumoral localization of fluorescent paramagnetic (M) PFC NP in the Vx2 rabbit model using proton (H) and fluorine (F) magnetic resonance (MR) imaging (3T) following intratracheal (IT) or IV administration. MRI results were corroborated by fluorescence microscopy. Dynamic H-MR and F-MR images (3T) obtained over 72 h demonstrated marked and progressive accumulation of M-PFC NP within primary lung Vx2 tumors during the first 12 h post IT administration. Marked H and F MR signal persisted for over 72 h. In contradistinction, IV M-PFC NP produced a modest transient signal during the initial 2 h post-injection that was consistent circumferential blood pool tumor enhancement. Fluorescence microscopy of excised tumors corroborated the MR results and revealed enormous intratumor NP deposition on day 3 after IT but not IV treatment. Rhodamine-phospholipid incorporated into the PFC nanoparticle surfactant was distributed widely within the tumor on day 3, which is consistent with a hemifusion-based contact drug delivery mechanism previously reported. Fluorescence microscopy also revealed similar high concentrations of M-PFC NP given IT for metastatic Vx2 lung tumors. Biodistribution studies in mice revealed that M-PFC NP given IV distributed into the reticuloendothelial organs, whereas, the same dosage given IT was basically not detected beyond the lung itself. PFC NP given IT did not impact rabbit behavior or impair respiratory function. PFC NP effects on cells in culture were negligible and when given IV or IT no changes in rabbit hematology nor serum clinical chemistry parameters were measured. IT delivery of PFC NP offered unique opportunity to locally deliver PFC NP in high concentrations into lung cancers with minimal extratumor systemic exposure.
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http://dx.doi.org/10.7150/thno.21466DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5743567PMC
December 2018

Bone-Induced Expression of Integrin β3 Enables Targeted Nanotherapy of Breast Cancer Metastases.

Cancer Res 2017 11 30;77(22):6299-6312. Epub 2017 Aug 30.

Department of Medicine, Division of Molecular Oncology, Washington University School of Medicine, St. Louis, Missouri.

Bone metastases occur in approximately 70% of metastatic breast cancer patients, often leading to skeletal injuries. Current treatments are mainly palliative and underscore the unmet clinical need for improved therapies. In this study, we provide preclinical evidence for an antimetastatic therapy based on targeting integrin β3 (β3), which is selectively induced on breast cancer cells in bone by the local bone microenvironment. In a preclinical model of breast cancer, β3 was strongly expressed on bone metastatic cancer cells, but not primary mammary tumors or visceral metastases. In tumor tissue from breast cancer patients, β3 was significantly elevated on bone metastases relative to primary tumors from the same patient ( = 42). Mechanistic investigations revealed that TGFβ signaling through SMAD2/SMAD3 was necessary for breast cancer induction of β3 within the bone. Using a micelle-based nanoparticle therapy that recognizes integrin αvβ3 (αvβ3-MPs of ∼12.5 nm), we demonstrated specific localization to breast cancer bone metastases in mice. Using this system for targeted delivery of the chemotherapeutic docetaxel, we showed that bone tumor burden could be reduced significantly with less bone destruction and less hepatotoxicity compared with equimolar doses of free docetaxel. Furthermore, mice treated with αvβ3-MP-docetaxel exhibited a significant decrease in bone-residing tumor cell proliferation compared with free docetaxel. Taken together, our results offer preclinical proof of concept for a method to enhance delivery of chemotherapeutics to breast cancer cells within the bone by exploiting their selective expression of integrin αvβ3 at that metastatic site. .
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http://dx.doi.org/10.1158/0008-5472.CAN-17-1225DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5841166PMC
November 2017

An unmet clinical need: The history of thrombus imaging.

J Nucl Cardiol 2019 Jun 12;26(3):986-997. Epub 2017 Jun 12.

Department of Medicine, Division of Cardiology, Washington University Medical School, St. Louis, MO, 63108, USA.

Robust thrombus imaging is an unresolved clinical unmet need dating back to the mid 1970s. While early molecular imaging approaches began with nuclear SPECT imaging, contrast agents for virtually all biomedical imaging modalities have been demonstrated in vivo with unique strengths and common weaknesses. Two primary molecular imaging targets have been pursued for thrombus imaging: platelets and fibrin. Some common issues noted over 40 years ago persist today. Acute thrombus is readily imaged with all probes and modalities, but aged thrombus remains a challenge. Similarly, anti-coagulation continues to interfere with and often negate thrombus imaging efficacy, but heparin is clinically required in patients suspected of pulmonary embolism, deep venous thrombosis or coronary ruptured plaque prior to confirmatory diagnostic studies have been executed and interpreted. These fundamental issues can be overcome, but an innovative departure from the prior approaches will be needed.
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http://dx.doi.org/10.1007/s12350-017-0942-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5741521PMC
June 2019

Anti-angiogenic Nanotherapy Inhibits Airway Remodeling and Hyper-responsiveness of Dust Mite Triggered Asthma in the Brown Norway Rat.

Theranostics 2017 1;7(2):377-389. Epub 2017 Jan 1.

Department of Medicine, Johns Hopkins University, Baltimore, MD, USA.

Although angiogenesis is a hallmark feature of asthmatic inflammatory responses, therapeutic anti-angiogenesis interventions have received little attention. Assess the effectiveness of anti-angiogenic Sn2 lipase-labile prodrugs delivered via αβ-micellar nanotherapy to suppress microvascular expansion, bronchial remodeling, and airway hyper-responsiveness in Brown Norway rats exposed to serial house dust mite (HDM) inhalation challenges. Anti-neovascular effectiveness of αβ-mixed micelles incorporating docetaxel-prodrug (Dxtl-PD) or fumagillin-prodrug (Fum-PD) were shown to robustly suppress neovascular expansion (p<0.01) in the upper airways/bronchi of HDM rats using simultaneous F/H MR neovascular imaging, which was corroborated by adjunctive fluorescent microscopy. Micelles without a drug payload (αβ-No-Drug) served as a carrier-only control. Morphometric measurements of HDM rat airway size (perimeter) and vessel number at 21d revealed classic vascular expansion in control rats but less vascularity (p<0.001) after the anti-angiogenic nanotherapies. CD31 RNA expression independently corroborated the decrease in airway microvasculature. Methacholine (MCh) induced respiratory system resistance (Rrs) was high in the HDM rats receiving αβ-No-Drug micelles while αβ-Dxtl-PD or αβ-Fum-PD micelles markedly and equivalently attenuated airway hyper-responsiveness and improved airway compliance. Total inflammatory BAL cells among HDM challenged rats did not differ with treatment, but αβ macrophages/monocytes were significantly reduced by both nanotherapies (p<0.001), most notably by the αβ-Dxtl-PD micelles. Additionally, αβ-Dxtl-PD decreased BAL eosinophil and αβ CD45 leukocytes relative to αβ-No-Drug micelles, whereas αβ-Fum-PD micelles did not. These results demonstrate the potential of targeted anti-angiogenesis nanotherapy to ameliorate the inflammatory hallmarks of asthma in a clinically relevant rodent model.
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http://dx.doi.org/10.7150/thno.16627DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5197071PMC
October 2017

Recent Advances in Fluorine Magnetic Resonance Imaging with Perfluorocarbon Emulsions.

Engineering (Beijing) 2015 Dec 16;1(4):475-489. Epub 2016 Mar 16.

Division of Cardiology, Washington University School of Medical, St. Louis, MO 63110, USA.

The research roots of fluorine (F) magnetic resonance imaging (MRI) date back over 35 years. Over that time span, H imaging flourished and was adopted worldwide with an endless array of applications and imaging approaches, making magnetic resonance an indispensable pillar of biomedical diagnostic imaging. For many years during this timeframe, F imaging research continued at a slow pace as the various attributes of the technique were explored. However, over the last decade and particularly the last several years, the pace and clinical relevance of F imaging has exploded. In part, this is due to advances in MRI instrumentation, F/H coil designs, and ultrafast pulse sequence development for both preclinical and clinical scanners. These achievements, coupled with interest in the molecular imaging of anatomy and physiology, and combined with a cadre of innovative agents, have brought the concept of F into early clinical evaluation. In this review, we attempt to provide a slice of this rich history of research and development, with a particular focus on liquid perfluorocarbon compound-based agents.
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http://dx.doi.org/10.15302/J-ENG-2015103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4841681PMC
December 2015

Dual-therapy with αvβ3-targeted Sn2 lipase-labile fumagillin-prodrug nanoparticles and zoledronic acid in the Vx2 rabbit tumor model.

Nanomedicine 2016 Jan 27;12(1):201-11. Epub 2015 Oct 27.

Division of Oncology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA. Electronic address:

Fumagillin, an unstable anti-angiogenesis mycotoxin, was synthesized into a stable lipase-labile prodrug and incorporated into integrin-targeted lipid-encapsulated nanoparticles (αvβ3-Fum-PD NP). Dual anti-angiogenic therapy combining αvβ3-Fum-PD NP with zoledronic acid (ZA), a long-acting osteoclast inhibitor with proposed anti-angiogenic effects, was evaluated. In vitro, αvβ3-Fum-PD NP reduced (P<0.05) endothelial cell viability without impacting macrophage viability. ZA suppressed (P<0.05) macrophage viability at high dosages but not endothelial cell proliferation. 3D MR neovascular imaging of rabbit Vx2 tumors showed no effect with ZA, whereas αvβ3-Fum-PD NP alone and with ZA decreased angiogenesis (P<0.05). Immunohistochemistry revealed decreased (P<0.05) microvascularity with αvβ3-Fum-PD NP and ZA and further microvascular reduction (P<0.05) with dual-therapy. In vivo, ZA did not decrease tumor macrophage numbers nor cancer cell proliferation, whereas αvβ3-Fum-PD-NPs reduced both measures. Dual-therapy with ZA and αvβ3-Fum-PD-NP may provide enhanced neo-adjuvant utility if macrophage ZA uptake is increased. From the Clinical Editor: Although anti-angiogenesis is one of the treatment modalities in the fight against cancer, many cancers become resistant to VEGF pathway inhibitors. In this article, the authors investigated the use of dual therapy using fumagillin, integrin-targeted lipid-encapsulated nanoparticles (αvβ3- Fum-PD NP) and zoledronic acid (ZA), in both in-vitro and in-vivo experiments. This combination approach may provide an insight to the design of future drugs against cancers.
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http://dx.doi.org/10.1016/j.nano.2015.10.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4727985PMC
January 2016

Synergy between surface and core entrapped metals in a mixed manganese-gadolinium nanocolloid affords safer MR imaging of sparse biomarkers.

Nanomedicine 2015 Apr 31;11(3):601-9. Epub 2015 Jan 31.

Division of Cardiology, Washington University School of Medicine, St. Louis, MO, USA. Electronic address:

High-relaxivity T1-weighted (T1w) MR molecular imaging nanoparticles typically present high surface gadolinium payloads that can elicit significant acute complement activation (CA). The objective of this research was to develop a high T1w contrast nanoparticle with improved safety. We report the development, optimization, and characterization of a gadolinium-manganese hybrid nanocolloid (MnOL-Gd NC; 138±10 (Dav)/nm; PDI: 0.06; zeta: -27±2 mV). High r1 particulate relaxivity with minute additions of Gd-DOTA-lipid conjugate to the MnOL nanocolloid surface achieved an unexpected paramagnetic synergism. This hybrid MnOL-Gd NC provided optimal MR TSE signal intensity at 5 nM/voxel and lower levels consistent with the level expression anticipated for sparse biomarkers, such as neovascular integrins. MnOL NC produced optimal MR TSE signal intensity at 10 nM/voxel concentrations and above. Importantly, MnOL-Gd NC avoided acute CA in vitro and in vivo while retaining minimal transmetallation risk. From the clinical editor: The authors developed a gadolinium-manganese hybrid nanocolloid (MnOL-Gd NC) in this study. These were used as a high-relaxivity paramagnetic MR molecular imaging agent in experimental models. It was shown that MnOL-Gd NC could provide high T1w MR contrast for targeted imaging. As the level of gadolinium used was reduced, there was also reduced risk of systemic side effects from complement activation.
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http://dx.doi.org/10.1016/j.nano.2014.12.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4389679PMC
April 2015

Atherosclerotic neovasculature MR imaging with mixed manganese-gadolinium nanocolloids in hyperlipidemic rabbits.

Nanomedicine 2015 Apr 31;11(3):569-78. Epub 2015 Jan 31.

Division of Cardiology, Washington University School of Medicine, St. Louis, MO, USA. Electronic address:

A high r1 relaxivity manganese-gadolinium nanocolloid (αvβ3-MnOL-Gd NC) was developed and effectively detected atherosclerotic angiogenesis in rabbits fed cholesterol-rich diets for 12 months using a clinical MRI scanner (3T). 3D mapping of neovasculature signal intensity revealed the spatial coherence and intensity of plaque angiogenic expansion, which may, with other high risk MR bioindicators, help identify high-risk patients with moderate (40% to 60%) vascular stenosis. Microscopy confirmed the predominant media and plaque distribution of fluorescent αvβ3-MnOL-Gd NC, mirroring the MR data. An expected close spatial association of αvβ3-integrin neovasculature and macrophages was noted, particularly within plaque shoulder regions. Manganese oleate bioelimination occurred via the biliary system into feces. Gd-DOTA was eliminated through the bile-fecal and renal excretion routes. αvβ3-MnOL-Gd NC offers an effective vehicle for T1w neovascular imaging in atherosclerosis. From the clinical editor: Cerebrovascular accidents are a leading cause of mortality and morbidity worldwide. The acute formation of thrombus following atherosclerotic plaque rupture has been well recognized as the etiology of stroke. The authors studied microanatomical features of vulnerable atherosclerotic plaque in this article, in an attempt to identify those with high risk of rupture. Gadolinium-manganese hybrid nanocolloid (MnOL-Gd NC) was developed as a novel contrast agent for MRI. They show that this agent is effective in providing neovascular imaging.
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http://dx.doi.org/10.1016/j.nano.2014.12.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4720435PMC
April 2015

MR cholangiography demonstrates unsuspected rapid biliary clearance of nanoparticles in rodents: implications for clinical translation.

Nanomedicine 2014 Oct 14;10(7):1385-8. Epub 2014 May 14.

Department of Medicine, Division of Cardiology, Washington University Medical School, St. Louis, MO, USA.

Due to their small size, lower cost, short reproduction cycle, and genetic manipulation, rodents have been widely used to test the safety and efficacy for pharmaceutical development in human disease. In this report, MR cholangiography demonstrated an unexpected rapid (<5 min) biliary elimination of gadolinium-perfluorocarbon nanoparticles (approximately 250 nm diameter) into the common bile duct and small intestine of rats, which is notably different from nanoparticle clearance patterns in larger animals and humans. Unawareness of this dissimilarity in nanoparticle clearance mechanisms between small animals and humans may lead to fundamental errors in predicting nanoparticle efficacy, pharmacokinetics, biodistribution, bioelimination, and toxicity. From the clinical editor: Comprehensive understanding of nanoparticle clearance is a clear prerequisite for human applications of nanomedicine-based therapeutic approaches. Through a novel use of MR cholangiography, this study demonstrates unusually rapid hepatic clearance of gadolinium-perfluorocarbon nanoparticles in rodents, in a pattern that is different than what is observed in larger animals and humans, raising awareness of important differences between common rodent-based models and larger mammals.
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http://dx.doi.org/10.1016/j.nano.2014.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4192078PMC
October 2014

Anti-angiogenesis therapy in the Vx2 rabbit cancer model with a lipase-cleavable Sn 2 taxane phospholipid prodrug using α(v)β₃-targeted theranostic nanoparticles.

Theranostics 2014 11;4(6):565-78. Epub 2014 Mar 11.

1. Department of Medicine, Washington University School of Medicine, St Louis, MO 63108, USA.

In nanomedicine, the hydrophobic nature of paclitaxel has favored its incorporation into many nanoparticle formulations for anti-cancer chemotherapy. At lower doses taxanes are reported to elicit anti-angiogenic responses. In the present study, the facile synthesis, development and characterization of a new lipase-labile docetaxel prodrug is reported and shown to be an effective anti-angiogenic agent in vitro and in vivo. The Sn 2 phosphatidylcholine prodrug was stably incorporated into the lipid membrane of α(v)β₃-integrin targeted perfluorocarbon (PFC) nanoparticles (α(v)β₃-Dxtl-PD NP) and did not appreciably release during dissolution against PBS buffer or plasma over three days. Overnight exposure of α(v)β₃-Dxtl-PD NP to plasma spiked with phospholipase enzyme failed to liberate the taxane from the membrane until the nanoparticle integrity was compromised with alcohol. The bioactivity and efficacy of α(v)β₃-Dxtl-PD NP in endothelial cell culture was as effective as Taxol(®) or free docetaxel in methanol at equimolar doses over 96 hours. The anti-angiogenesis effectiveness of α(v)β₃-Dxtl-PD NP was demonstrated in the Vx2 rabbit model using MR imaging of angiogenesis with the same α(v)β₃-PFC nanoparticle platform. Nontargeted Dxtl-PD NP had a similar MR anti-angiogenesis response as the integrin-targeted agent, but microscopically measured decreases in tumor cell proliferation and increased apoptosis were detected only for the targeted drug. Equivalent dosages of Abraxane(®) given over the same treatment schedule had no effect on angiogenesis when compared to control rabbits receiving saline only. These data demonstrate that α(v)β₃-Dxtl-PD NP can reduce MR detectable angiogenesis and slow tumor progression in the Vx2 model, whereas equivalent systemic treatment with free taxane had no benefit.
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http://dx.doi.org/10.7150/thno.7581DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3982128PMC
January 2015

Antagonizing the αv β3 integrin inhibits angiogenesis and impairs woven but not lamellar bone formation induced by mechanical loading.

J Bone Miner Res 2014 Sep;29(9):1970-80

Department of Orthopaedic Surgery, Musculoskeletal Research Center, Washington University in St. Louis, St. Louis, MO, USA; Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA.

Angiogenesis and osteogenesis are critically linked, although the role of angiogenesis is not well understood in osteogenic mechanical loading. In this study, either damaging or non-damaging cyclic axial compression was used to generate woven bone formation (WBF) or lamellar bone formation (LBF), respectively, at the mid-diaphysis of the adult rat forelimb. αv β3 integrin-targeted nanoparticles or vehicle was injected intravenously after mechanical loading. β3 integrin subunit expression on vasculature was maximal 7 days after damaging mechanical loading, but was still robustly expressed 14 days after loading. Accordingly, targeted nanoparticle delivery in WBF-loaded limbs was increased compared with non-loaded limbs. Vascularity was dramatically increased after WBF loading (+700% on day 14) and modestly increased after LBF loading (+50% on day 14). This increase in vascularity was inhibited by nanoparticle treatment in both WBF- and LBF-loaded limbs at days 7 and 14 after loading. Decreased vascularity led to diminished woven, but not lamellar, bone formation. Decreased woven bone formation resulted in impaired structural properties of the skeletal repair, particularly in post-yield behavior. These results demonstrate that αv β3 integrin-mediated angiogenesis is critical for recovering fracture resistance after bone injury but is not required for bone modeling after modest mechanical strain. © 2014 American Society for Bone and Mineral Research.
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http://dx.doi.org/10.1002/jbmr.2223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4323187PMC
September 2014

Characterization of early neovascular response to acute lung ischemia using simultaneous (19)F/ (1)H MR molecular imaging.

Angiogenesis 2014 Jan 6;17(1):51-60. Epub 2013 Aug 6.

Department of Medicine, Washington University School of Medicine, 660 S. Euclid, Campus Box 8215, St. Louis, MO, 63110, USA,

Angiogenesis is an important constituent of many inflammatory pulmonary diseases, which has been unappreciated until recently. Early neovascular expansion in the lungs in preclinical models and patients is very difficult to assess noninvasively, particularly quantitatively. The present study demonstrated that (19)F/(1)H MR molecular imaging with αvβ3-targeted perfluorocarbon nanoparticles can be used to directly measure neovascularity in a rat left pulmonary artery ligation (LPAL) model, which was employed to create pulmonary ischemia and induce angiogenesis. In rats 3 days after LPAL, simultaneous (19)F/(1)H MR imaging at 3T revealed a marked (19)F signal in animals 2 h following αvβ3-targeted perfluorocarbon nanoparticles [(19)F signal (normalized to background) = 0.80 ± 0.2] that was greater (p = 0.007) than the non-targeted (0.30 ± 0.04) and the sham-operated (0.07 ± 0.09) control groups. Almost no (19)F signal was found in control right lung with any treatment. Competitive blockade of the integrin-targeted particles greatly decreased the (19)F signal (p = 0.002) and was equivalent to the non-targeted control group. Fluorescent and light microscopy illustrated heavy decorating of vessel walls in and around large bronchi and large pulmonary vessels. Focal segmental regions of neovessel expansion were also noted in the lung periphery. Our results demonstrate that (19)F/(1)H MR molecular imaging with αvβ3-targeted perfluorocarbon nanoparticles provides a means to assess the extent of systemic neovascularization in the lung.
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http://dx.doi.org/10.1007/s10456-013-9377-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3947345PMC
January 2014

Molecular MR imaging of neovascular progression in the Vx2 tumor with αvβ3-targeted paramagnetic nanoparticles.

Radiology 2013 Aug 14;268(2):470-80. Epub 2013 Jun 14.

Department of Medicine, Washington University Medical School, 660 S. Euclid Ave, Campus Box 8215, St Louis, MO 63108, USA.

Purpose: To assess the dependence of neovascular molecular magnetic resonance (MR) imaging on relaxivity (r1) of αvβ3-targeted paramagnetic perfluorocarbon (PFC) nanoparticles and to delineate the temporal-spatial consistency of angiogenesis assessments for individual animals.

Materials And Methods: Animal protocols were approved by the Washington University Animal Studies Committee. Proton longitudinal and transverse relaxation rates of αvβ3-targeted and nontargeted PFC nanoparticles incorporating gadolinium diethylenetrianime pentaacedic acid (Gd-DTPA) bisoleate (BOA) or gadolinium tetraazacyclododecane tetraacetic acid (Gd-DOTA) phosphatidylethanolamine (PE) into the surfactant were measured at 3.0 T. These paramagnetic nanoparticles were compared in 30 New Zealand White rabbits (four to six rabbits per group) 14 days after implantation of a Vx2 tumor. Subsequently, serial MR (3.0 T) neovascular maps were developed 8, 14, and 16 days after tumor implantation by using αvβ3-targeted Gd-DOTA-PE nanoparticles (n = 4) or nontargeted Gd-DOTA-PE nanoparticles (n = 4). Data were analyzed with analysis of variance and nonparametric statistics.

Results: At 3.0 T, Gd-DTPA-BOA nanoparticles had an ionic r1 of 10.3 L · mmol(-1) · sec(-1) and a particulate r1 of 927000 L · mmol(-1) · sec(-1). Gd-DOTA-PE nanoparticles had an ionic r1 of 13.3 L · mmol(-1) · sec(-1) and a particulate r1 of 1 197000 L · mmol(-1) · sec(-1). Neovascular contrast enhancement in Vx2 tumors (at 14 days) was 5.4% ± 1.06 of the surface volume with αvβ3-targeted Gd-DOTA-PE nanoparticles and 3.0% ± 0.3 with αvβ3-targeted Gd-DTPA-BOA nanoparticles (P = .03). MR neovascular contrast maps of tumors 8, 14, and 16 days after implantation revealed temporally consistent and progressive surface enhancement (1.0% ± 0.3, 4.5% ± 0.9, and 9.3% ± 1.4, respectively; P = .0008), with similar time-dependent changes observed among individual animals.

Conclusion: Temporal-spatial patterns of angiogenesis for individual animals were followed to monitor longitudinal tumor progression. Neovasculature enhancement was dependent on the relaxivity of the targeted agent.
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http://dx.doi.org/10.1148/radiol.13120789DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3721054PMC
August 2013

Angiogenesis is required for stress fracture healing in rats.

Bone 2013 Jan 5;52(1):212-9. Epub 2012 Oct 5.

Department of Orthopaedic Surgery, Washington University in St. Louis, Saint Louis, MO, USA.

Although angiogenesis and osteogenesis are critically linked, the importance of angiogenesis for stress fracture healing is unknown. In this study, mechanical loading was used to create a non-displaced stress fracture in the adult rat forelimb. Fumagillin, an anti-angiogenic agent, was used as the water soluble analogue TNP-470 (25mg/kg) as well as incorporated into lipid-encapsulated α(v)β(3) integrin targeted nanoparticles (0.25mg/kg). In the first experiment, TNP-470 was administered daily for 5 days following mechanical loading, and changes in gene expression, vascularity, and woven bone formation were quantified. Although no changes in vascularity were detected 3 days after loading, treatment-related downregulation of angiogenic (Pecam1) and osteogenic (Bsp, Osx) genes was observed at this early time point. On day 7, microCT imaging of loaded limbs revealed diminished woven bone formation in treated limbs compared to vehicle treated limbs. In the second experiment, α(v)β(3) integrin targeted fumagillin nanoparticles were administered as before, albeit with a 100-fold lower dose, and changes in vascularity and woven bone formation were determined. There were no treatment-related changes in vessel count or volume 3 days after loading, although fewer angiogenic (CD105 positive) blood vessels were present in treated limbs compared to vehicle treated limbs. This result manifested on day 7 as a reduction in total vascularity, as measured by histology (vessel count) and microCT (vessel volume). Similar to the first experiment, treated limbs had diminished woven bone formation on day 7 compared to vehicle treated limbs. These results indicate that angiogenesis is required for stress fracture healing, and may have implications for inducing rapid repair of stress fractures.
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http://dx.doi.org/10.1016/j.bone.2012.09.035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3513671PMC
January 2013

Antiangiogenic nanotherapy with lipase-labile Sn-2 fumagillin prodrug.

Nanomedicine (Lond) 2012 Oct 18;7(10):1507-19. Epub 2012 Jun 18.

Division of Cardiology, Washington University School of Medicine, 4320 Forest Park Avenue, Saint Louis, MO 63108, USA.

Background: The chemical instability of antiangiogenic fumagillin, combined with its poor retention during intravascular transit, requires an innovative solution for clinical translation. We hypothesized that an Sn-2 lipase-labile fumagillin prodrug, in combination with a contact-facilitated drug delivery mechanism, could be used to address these problems.

Methods: α(v)β(3)-targeted and nontargeted nanoparticles with and without fumagillin in the prodrug or native forms were evaluated in vitro and in vivo in the Matrigel™ (BD Biosciences, CA, USA) plug model of angiogenesis in mice.

Results: In vitro experiments demonstrated that the new fumagillin prodrug decreased viability at least as efficacious as the parent compound, on an equimolar basis. In the Matrigel mouse angiogenesis model, α(v)β(3)-fumagillin prodrug decreased angiogenesis as measured by MRI (3T), while the neovasculature was unaffected with the control nanoparticles.

Conclusion: The present approach resolved the previously intractable problems of drug instability and premature release in transit to target sites.
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http://dx.doi.org/10.2217/nnm.12.27DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3498609PMC
October 2012

Sensitive biological detection with a soluble and stable polymeric paramagnetic nanocluster.

J Am Chem Soc 2012 Jun 13;134(25):10377-80. Epub 2012 Jun 13.

C-TRAIN and Division of Cardiology, Washington University School of Medicine, 4320 Forest Park Avenue, Saint Louis, Missouri 63108, USA.

We describe the design, synthesis, and biological characterization of manganese oxocluster-based "single molecule magnets (SMMs)". We demonstrate that polymeric micellar nanoparticles can serve as a carrier and help to stabilize delicate SMM molecules from breaking down easily and thus prevent their property loss. Concentrating thousands of Mn-clusters per micelle provided a high ionic and per-particle relaxivity allowing sensitive MR imaging in vivo. This reports one of the earliest examples of in vivo imaging of a rationally designed polymeric micelle that features SMM.
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http://dx.doi.org/10.1021/ja3040366DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3397310PMC
June 2012

An early investigation of ytterbium nanocolloids for selective and quantitative "multicolor" spectral CT imaging.

ACS Nano 2012 Apr 8;6(4):3364-70. Epub 2012 Mar 8.

C-TRAIN and Division of Cardiology, Washington University School of Medicine, 4320 Forest Park Avenue, St. Louis, Missouri 63108, United States.

We report a novel molecular imaging agent based on ytterbium designed for use with spectral "multicolor" computed tomography (CT). Spectral CT or multicolored CT provides all of the benefits of traditional CT, such as rapid tomographic X-ray imaging, but in addition, it simultaneously discriminates metal-rich contrast agents based on the element's unique X-ray K-edge energy signature. Our synthetic approach involved the use of organically soluble Yb(III) complex to produce nanocolloids of Yb of noncrystalline nature incorporating a high density of Yb (>500K/nanoparticle) into a stable metal particle. The resultant particles are constrained to vasculature (∼200 nm) and are highly selective for binding fibrin in the ruptured atherosclerotic plaque. Nanoparticles exhibited excellent signal sensitivity, and the spectral CT technique uniquely discriminates the K-edge signal (60 keV) of Yb from calcium (bones). Bioelimination and preliminary biodistribution reflected the overall safety and defined clearance of these particles in a rodent model.
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http://dx.doi.org/10.1021/nn300392xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3529639PMC
April 2012

Manganese-based MRI contrast agents: past, present and future.

Tetrahedron 2011 Nov;67(44):8431-8444

Division of Cardiology and C-TRAIN, Washington University School of Medicine, St. Louis, MO 63108 USA.

Paramagnetic and superparamagnetic metals are used as contrast materials for magnetic resonance (MR) based techniques. Lanthanide metal gadolinium (Gd) has been the most widely explored, predominant paramagnetic contrast agent until the discovery and association of the metal with nephrogenic systemic fibrosis (NSF), a rare but serious side effects in patients with renal or kidney problems. Manganese was one of the earliest reported examples of paramagnetic contrast material for MRI because of its efficient positive contrast enhancement. In this review, manganese based contrast agent approaches are discussed with a particular emphasis on their synthetic approaches. Both small molecules based typical blood pool contrast agents and more recently developed novel nanometer sized materials are reviewed focusing on a number of successful molecular imaging examples.
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http://dx.doi.org/10.1016/j.tet.2011.07.076DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3203535PMC
November 2011

Rationale for a nanomedicine approach to thrombolytic therapy.

Stroke 2010 Oct;41(10 Suppl):S42-4

Department of Medicine, Division of Cardiology, 4320 Forest Park Ave, Suite 101, St Louis, MO 63108, USA.

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http://dx.doi.org/10.1161/STROKEAHA.110.598656DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2953722PMC
October 2010

Simultaneous dual frequency 1H and 19F open coil imaging of arthritic rabbit knee at 3T.

IEEE Trans Med Imaging 2011 Jan 9;30(1):22-7. Epub 2010 Aug 9.

Department of Medicine, Cardiology Division,Washington University School of Medicine, St. Louis, MO 63110, USA.

The combination of sensitive magnetic resonance techniques with a selective site-targeted nanoparticle contrast agent has a demonstrated utility for molecular imaging studies. By detecting a unique signature of the contrast agent, this approach can be employed to identify specific bio-molecular markers and observe cellular-level processes within a large and complex organism (e.g., in vivo rabbit). The objective of the present investigation was to design, fabricate and characterize a radio-frequency (RF) coil for the dual frequency ((1)H and (19)F) simultaneous collection of both nuclei images in a 3T field, in order to facilitate studies of arthritic knee degradation in rabbits. The coil supports both transmit and receive modes. The supporting activities included: 1) establishing a technical database for calculating the required coil parameters, 2) selection of a favorable coil geometry, and 3) adaption of existing RF measurement techniques to the design, development and electrical evaluation of the coil. The coil is used in conjunction with a Philips Medical Systems clinical MRI scanner, requiring all RF simultaneous dual frequency ((1)H and (19)F) coils to operate in both transmit and receive modes. A commercial version of SPICE (simulation program with integrated circuit emphasis) was used to estimate significant operational parameters prior to fabricating the imaging coil. Excellent images were obtained with the fabricated coil and no operational problems were observed that would limit the use of other coil geometries and field strengths.
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http://dx.doi.org/10.1109/TMI.2010.2056689DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3047411PMC
January 2011

Angiogenesis imaging with vascular-constrained particles: the why and how.

Eur J Nucl Med Mol Imaging 2010 Aug;37 Suppl 1:S114-26

Washington University Medical School, St. Louis, MO 63146, USA.

Angiogenesis is a keystone in the treatment of cancer and potentially many other diseases. In cancer, first-generation antiangiogenic therapeutic approaches have demonstrated survival benefit in subsets of patients, but their high cost and notable adverse side effect risk have fueled alternative development efforts to personalize patient selection and reduce off-target effects. In parallel, rapid advances in cost-effective genomic profiling and sensitive early detection of high-risk biomarkers for cancer, atherosclerosis, and other angiogenesis-related pathologies will challenge the medical imaging community to identify, characterize, and risk stratify patients early in the natural history of these disease processes. Conventional diagnostic imaging techniques were not intended for such sensitive and specific detection, which has led to the emergence of novel noninvasive biomedical imaging approaches. The overall intent of molecular imaging is to achieve greater quantitative characterization of pathologies based on microanatomical, biochemical, or functional assessments; in many approaches, the capacity to deliver effective therapy, e.g., antiangiogenic therapy, can be combined. Agents with both diagnostic and therapy attributes have acquired the moniker "theranostics." This review will explore biomedical imaging options being pursued to better segment and treat patients with angiogenesis-influenced disease using vascular-constrained contrast platform technologies.
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http://dx.doi.org/10.1007/s00259-010-1502-5DOI Listing
August 2010

MR angiogenesis imaging with Robo4- vs. alphaVbeta3-targeted nanoparticles in a B16/F10 mouse melanoma model.

FASEB J 2010 Nov 28;24(11):4262-70. Epub 2010 Jun 28.

Washington University Medical School, St. Louis, MO 63108, USA.

The primary objective of this study was to utilize MR molecular imaging to compare the 3-dimensional spatial distribution of Robo4 and α(V)β(3)-integrin as biosignatures of angiogenesis, in a rapidly growing, syngeneic tumor. B16-F10 melanoma-bearing mice were imaged with magnetic resonance (MR; 3.0 T) 11 d postimplantation before and after intravenous administration of either Robo4- or α(V)β(3)-targeted paramagnetic nanoparticles. The percentage of MR signal-enhanced voxels throughout the tumor volume was low and increased in animals receiving α(V)β(3)- and Robo4-targeted nanoparticles. Neovascular signal enhancement was predominantly associated with the tumor periphery (i.e., outer 50% of volume). Microscopic examination of tumors coexposed to the Robo4- and α(V)β(3)-targeted nanoparticles corroborated the MR angiogenesis mapping results and further revealed that Robo4 expression generally colocalized with α(V)β(3)-integrin. Robo4- and α(V)β(3)-targeted nanoparticles were compared to irrelevant or nontargeted control groups in all modalities. These results suggest that α(V)β(3)-integrin and Robo4 are useful biomarkers for noninvasive MR molecular imaging in syngeneic mouse tumors, but α(V)β(3)-integrin expression was more detectable by MR at 3.0 T than Robo4. Noninvasive, neovascular assessments of the MR signal of Robo4, particularly combined with α(V)β(3)-integrin expression, may help define tumor character prior to and following cancer therapy.
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http://dx.doi.org/10.1096/fj.10-157933DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3066028PMC
November 2010

Nanomedicine strategies for molecular targets with MRI and optical imaging.

Future Med Chem 2010 Mar;2(3):471-90

The science of 'theranostics' plays a crucial role in personalized medicine, which represents the future of patient management. Over the last decade an increasing research effort has focused on the development of nanoparticle-based molecular-imaging and drug-delivery approaches, emerging as a multidisciplinary field that shows promise in understanding the components, processes, dynamics and therapies of a disease at a molecular level. The potential of nanometer-sized agents for early detection, diagnosis and personalized treatment of diseases is extraordinary. They have found applications in almost all clinically relevant biomedical imaging modality. In this review, a number of these approaches will be presented with a particular emphasis on MRI and optical imaging-based techniques. We have discussed both established molecular-imaging approaches and recently developed innovative strategies, highlighting the seminal studies and a number of successful examples of theranostic nanomedicine, especially in the areas of cardiovascular and cancer therapy.
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http://dx.doi.org/10.4155/fmc.10.5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2871711PMC
March 2010

High sensitivity: high-resolution SPECT-CT/MR molecular imaging of angiogenesis in the Vx2 model.

Invest Radiol 2009 Jan;44(1):15-22

Washington University Medical School, St Louis, MO 63108, USA.

Objectives: The use of antiangiogenic therapy in conjunction with traditional chemotherapy is becoming increasingly in cancer management, but the optimal benefit of these targeted pharmaceuticals has been limited to a subset of the population treated. Improved imaging probes that permit sensitive detection and high-resolution characterization of tumor angiogenesis could improve patient risk-benefit stratification. The overarching objective of these experiments was to develop a dual modality alpha(nu)beta3-targeted nanoparticle molecular imaging agent that affords sensitive nuclear detection in conjunction with high-resolution MR characterization of tumor angiogenesis.

Materials And Methods: In part 1, New Zealand white rabbits (n = 21) bearing 14d Vx2 tumor received either alpha(nu)beta3-targeted 99mTc nanoparticles at doses of 11, 22, or 44 MBq/kg, nontargeted 99mTc nanoparticles at 22 MBq/kg, or alpha(nu)beta3-targeted 99mTc nanoparticles (22 MBq/kg) competitively inhibited with unlabeled alpha(nu)beta3-nanoparticles. All animals were imaged dynamically over 2 hours with a planar camera using a pinhole collimator. In part 2, the effectiveness of alpha(nu)beta3-targeted 99mTc nanoparticles in the Vx2 rabbit model was demonstrated using clinical SPECT-CT imaging techniques. Next, MR functionality was incorporated into alpha(nu)beta3-targeted 99mTc nanoparticles by inclusion of lipophilic gadolinium chelates into the outer phospholipid layer, and the concept of high sensitivity - high-resolution detection and characterization of tumor angiogenesis was shown using sequential SPECT-CT and MR molecular imaging with 3D neovascular mapping.

Results: alpha(nu)beta3-Targeted 99mTc nanoparticles at 22 MBq/kg produced the highest tumor-to-muscle contrast ratio (8.56 +/- 0.13, TMR) versus the 11 MBq/kg (7.32 +/- 0.12) and 44 MBq/kg (6.55 +/- 0.07) doses, (P < 0.05). TMR of nontargeted particles at 22.2 MBq/kg (5.48 +/- 0.09) was less (P < 0.05) than the equivalent dosage of alpha(nu)beta3-targeted 99mTc nanoparticles. Competitively inhibition of 99mTc alpha(nu)beta3-integrin-targeted nanoparticles at 22.2 MBq/kg reduced (P < 0.05) TMR (5.31 +/- 0.06) to the nontargeted control contrast level. Multislice CT imaging could not distinguish the presence of Vx2 tumor implanted in the popliteal fossa from lymph nodes in the same fossa or in the contralateral leg. However, the use of 99mTc alpha(nu)beta3-nanoparticles with SPECT-CT produced a clear neovasculature signal from the tumor that was absent in the nonimplanted hind leg. Using alpha(nu)beta3-targeted 99mTc-gadolinium nanoparticles, the sensitive detection of the Vx2 tumor was extended to allow MR molecular imaging and 3D mapping of angiogenesis in the small tumor, revealing an asymmetrically distributed, patchy neovasculature along the periphery of the cancer.

Conclusion: Dual modality molecular imaging with alpha(nu)beta3-targeted 99mTc-gadolinium nanoparticles can afford highly sensitive and specific localization of tumor angiogenesis, which can be further characterized with high-resolution MR neovascular mapping, which may predict responsiveness to antiangiogenic therapy.
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http://dx.doi.org/10.1097/RLI.0b013e31818935ebDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2703786PMC
January 2009

Three-dimensional MR mapping of angiogenesis with alpha5beta1(alpha nu beta3)-targeted theranostic nanoparticles in the MDA-MB-435 xenograft mouse model.

FASEB J 2008 Dec 12;22(12):4179-89. Epub 2008 Aug 12.

Washington University Medical School, Campus Box 8215, 4320 Forest Park Ave., St. Louis, MO 63108, USA.

Our objectives were 1) to characterize angiogenesis in the MDA-MB-435 xenograft mouse model with three-dimensional (3D) MR molecular imaging using alpha(5)beta(1)(RGD)- or irrelevant RGS-targeted paramagnetic nanoparticles and 2) to use MR molecular imaging to assess the antiangiogenic effectiveness of alpha(5)beta(1)(alpha(nu)beta(3))- vs. alpha(nu)beta(3)-targeted fumagillin (50 mug/kg) nanoparticles. Tumor-bearing mice were imaged with MR before and after administration of either alpha(5)beta(1)(RGD) or irrelevant RGS-paramagnetic nanoparticles. In experiment 2, mice received saline or alpha(5)beta(1)(alpha(nu)beta(3))- or alpha(nu)beta(3)-targeted fumagillin nanoparticles on days 7, 11, 15, and 19 posttumor implant. On day 22, MRI was performed using alpha(5)beta(1)(alpha(nu)beta(3))-targeted paramagnetic nanoparticles to monitor the antiangiogenic response. 3D reconstructions of alpha(5)beta(1)(RGD)-signal enhancement revealed a sparse, asymmetrical pattern of angiogenesis along the tumor periphery, which occupied <2.0% tumor surface area. alpha(5)beta(1)-targeted rhodamine nanoparticles colocalized with FITC-lectin corroborated the peripheral neovascular signal. alpha(5)beta(1)(alpha(nu)beta(3))-fumagillin nanoparticles decreased neovasculature to negligible levels relative to control; alpha(nu)beta(3)-targeted fumagillin nanoparticles were less effective (P>0.05). Reduction of angiogenesis in MDA-MB-435 tumors from low to negligible levels did not decrease tumor volume. MR molecular imaging may be useful for characterizing tumors with sparse neovasculature that are unlikely to have a reduced growth response to targeted antiangiogenic therapy.
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http://dx.doi.org/10.1096/fj.08-112060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2614609PMC
December 2008

Minute dosages of alpha(nu)beta3-targeted fumagillin nanoparticles impair Vx-2 tumor angiogenesis and development in rabbits.

FASEB J 2008 Aug 24;22(8):2758-67. Epub 2008 Mar 24.

Washington University Medical School, Campus Box 8215, 4320 Forest Park Ave., St. Louis, MO 63108, USA.

Fumagillin suppresses angiogenesis in cancer models and clinical trials, but it is associated with neurotoxicity at systemic doses. In this study, alpha(nu)beta(3)-targeted fumagillin nanoparticles were used to suppress the neovasculature and inhibit Vx-2 adenocarcinoma development using minute drug doses. Tumor-bearing rabbits were treated on days 6, 9, and 12 postimplantation with alpha(nu)beta(3)-targeted fumagillin nanoparticles (30 microg/kg), alpha(nu)beta(3)-targeted nanoparticles without drug, nontargeted fumagillin nanoparticles (30 microg/kg) or saline. On day 16, MRI was performed with alpha(nu)beta(3)-targeted paramagnetic nanoparticles to quantify tumor size and assess neovascularity. Tumor volume was reduced among rabbits receiving alpha(nu)beta(3)-targeted fumagillin nanoparticles (470+/-120 mm(3)) compared with the three control groups: nontargeted fumagillin nanoparticles (1370+/-300 mm(3), P<0.05), alpha(nu)beta(3)-targeted nanoparticles without drug (1080+/-180 mm(3), P<0.05) and saline (980+/-80 mm(3), P<0.05). MR molecular imaging of control rabbits (no fumagillin) revealed a predominant peripheral distribution of neovascularity representing 7.2% of the tumor rim volume, which decreased to 2.8% (P<0.05) with alpha(nu)beta(3)-targeted fumagillin nanoparticle treatment. Microscopically, the tumor parenchyma tended to show T-cell infiltration after targeted fumagillin treatment, which was not appreciated in control animals. These results suggest that alpha(nu)beta(3)-targeted fumagillin nanoparticles could provide a safe and effective means to deliver MetAP2 inhibitors alone or in combination with cytotoxic or immunotherapy.
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http://dx.doi.org/10.1096/fj.07-103929DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2493462PMC
August 2008

Development of novel poly(ethylene glycol)-based vehicles for gene delivery.

Biotechnol Bioeng 2007 Apr;96(5):967-76

Department of Biomedical Engineering and Center for Materials Innovation, Washington University, St. Louis, Missouri 63130, USA.

The purpose of this research was to develop and characterize a gene delivery vehicle with a poly(ethylene glycol) (PEG) backbone with the aim of overcoming limitations, such as cytotoxicity and rapid clearance, associated with current commonly used non-viral carriers. PEG was functionalized with DNA-binding peptides (DBPs) to make a vehicle (DBP-PEG) capable of condensing DNA. Complexes of plasmid DNA and DBP-PEG were formed and characterized by measuring particle size, zeta potential, and transfection efficiency as a function of N:P charge ratios (DBP-PEG amino groups:DNA phosphate). Dynamic light scattering showed that DBP-PEG was able to condense DNA efficiently resulting in a population of particles in the range of 250-300 nm. Neutral or slightly positive zeta potentials were measured for charge ratios of 3.5:1 and greater. DBP-PEG/DNA complexes, made with plasmids encoding the green fluorescent protein (GFP) and beta-Galactosidase (beta-Gal) genes, were used to transfect Chinese hamster ovary (CHO) cells. DBP-PEG/DNA was capable of transfecting cells and maximum transfection efficiency was observed for N:P ratios from 4:1 to 5:1, corresponding to zeta potentials from -4 to +1.6 mV. The effect of the DBP-PEG vehicle on cell viability was assayed. DBP-PEG was associated with a higher percentage of viable cells ( approximately 95%) than either polyethylenimine (PEI) or poly-L-lysine (PLL), and with transfection efficiency greater than PLL, but with somewhat lower than PEI. The results of this work demonstrate that PEG can be used as the backbone for gene delivery vehicles.
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http://dx.doi.org/10.1002/bit.21199DOI Listing
April 2007