Monitoring Of Biodistribution Research Articles

Spatio-temporal biodistribution of 89Zr-oxine labeled huLym-1-A-BB3z-CAR T-cells by PET imaging in a preclinical tumor model

Quantitative in vivo monitoring of cell biodistribution offers assessment of treatment efficacy in real-time and can provide guidance for further optimization of chimeric antigen receptor (CAR) modified cell therapy. We evaluated the utility of a non-invasive, serial 89Zr-oxine PET imaging to assess optimal dosing for huLym-1-A-BB3z-CAR T-cell directed to Lym-1-positive Raji lymphoma xenograft in NOD Scid-IL2Rgammanull (NSG) mice. In vitro experiments showed no detrimental effects in cell health and function following 89Zr-oxine labeling. In vivo experiments employed simultaneous PET/MRI of Raji-bearing NSG mice on day 0 (3 h), 1, 2, and 5 after intravenous administration of low (1.87 ± 0.04 × 106 cells), middle (7.14 ± 0.45 × 106 cells), or high (16.83 ± 0.41 × 106 cells) cell dose. Biodistribution (%ID/g) in regions of interests defined over T1-weighted MRI, such as blood, bone, brain, liver, lungs, spleen, and tumor, were analyzed from PET images. Escalating doses of CAR T-cells resulted in dose-dependent %ID/g biodistributions in all regions. Middle and High dose groups showed significantly higher tumor %ID/g compared to Low dose group on day 2. Tumor-to-blood ratios showed the enhanced extravascular tumor uptake by day 2 in the Low dose group, while the Middle dose showed significant tumor accumulation starting on day 1 up to day 5. From these data obtained over time, it is apparent that intravenously administered CAR T-cells become trapped in the lung for 3–5 h and then migrate to the liver and spleen for up to 2–3 days. This surprising biodistribution data may be responsible for the inactivation of these cells before targeting solid tumors. Ex vivo biodistributions confirmed in vivo PET-derived biodistributions. According to these studies, we conclude that in vivo serial PET imaging with 89Zr-oxine labeled CAR T-cells provides real-time monitoring of biodistributions crucial for interpreting efficacy and guiding treatment in patient care.

Monitoring 111In-labelled polyisocyanopeptide (PIC) hydrogel wound dressings in full-thickness wounds.

Wounds often result in scarring, prolonged morbidity, and loss of function. New interactive and modifiable hydrogel wound dressings are being developed for these injuries. Polyisocyanopeptide (PIC) gel is a promising thermosensitive hydrogel having several characteristics that can facilitate wound repair, including ease of application/removal and strain-stiffening properties that mimic extracellular matrix components. However, it is unknown whether the PIC gel remains in the wound for a clinically relevant time period. Therefore, PIC polymers were functionalized with a DTPA group allowing labelling with Indium-111 (111In). Following application of this radiolabelled gel to splinted and non-splinted murine full-thickness skin wounds the signal was monitored using SPECT/CT imaging for 7 days. The SPECT signal from the PIC gel was highly stable and covered the complete wound area. Non-bound 111In-EDTA was rapidly cleared via the kidneys to the urine. The impact of PIC gels on wound repair was further studied visually and histologically. Radiolabelled PIC gel was observed to move both over and under the skin, while histological analysis demonstrated that part of the gel became encapsulated within the wound repair tissue, but did not delay wound closure or otherwise impair wound healing. This work illustrates for the first time the use of 111In-labelled PIC gels for diagnostic and monitoring purposes and describes the use of PIC in the (non-)splinted murine skin wound model. It was found that PIC gels remained in splinted and non-splinted full-thickness skin wounds during wound repair. This warrants the continuation of developing the PIC gel into a clinically advanced wound dressing.

Abstract 3041: Molecular, histopathologic, MRI and PET findings in syngeneic oncologic mouse models

Abstract Experimental tumors raised in rodents represent an important preclinical tool to develop innovative anticancer compounds before clinical testing. Amongst others such models include solid tumors raised in syngeneic fully immunocompetent hosts and tumors spontaneously growing in genetically engineered mice (GEM) and derivate thereof. These model platforms have gained additional value since the manipulation of the immune system to fight cancer has led to tangible benefits for cancer patients. Imaging has become important part of the basic and translational research. It enables e.g. metabolic activity, volumetric and biodistribution monitoring within same individual over time. Magnetic resonance imaging (MRI) and positron emission tomography (PET) are widely used for clinical diagnosis and disease follow up. Choosing the most suitable imaging application depends of the prioritization of features. MRI offers unprecedented soft tissue contrast, high spatial resolution and non-invasive nature renders MRI in rodents a perfect tool for preclinical work in oncological applications. Similarly to clinical setting, MRI in rodents is used for detection of the tumors, evaluation of therapeutic response and induced changes, with longitudinal follow-up for early detection of possible tumor recurrence. PET is an excellent tool to study tumor metabolism, location as well biodistribution of novel antibodies. The purpose of this work was to study molecular as well volumetric, metabolic and functional changes in syngeneic oncological mouse model using MRI, MRS and PET imaging. Our panel consists of 32 fully characterized mouse tumor models covering 12 major cancer types. We characterized those models by molecular profiling (whole exome sequencing and RNAseq), histopathological examination (tissue micro array as well as whole slide analysis of Ki67, CD31, SMA, TIL infiltration) and sensitivity towards checkpoint inhibitors. Amongst other findings we saw an enhanced activity of anti-CTLA-4 treatment in combination with anti-PD1 in 4T1 orthotopically implanted into the mammary fat pad in comparison to single agent therapy. In a follow-up study we implanted 14 mice with breast cancer cell line 4T1 orthotopically into the mammary fat pad. When tumors were palpable treatment with the checkpoint inhibitor combination started. During the course of the experiment we determined tumor volume of the primary lesion twice weekly. In addition to molecular markers, MRI, MRS and PET were applied to study changes in tumor over cancer progression. As a conclusion, several syngeneic oncological mouse models have been characterized using molecular profiling, histological techniques and in vivo imaging. These readouts provide a powerful and translational research tool together with oncological disease animal models allowing comprehensive evaluation of disease progression and treatment interventions for in vivo studies. Citation Format: Julia Schueler, Artem Shatillo, Jussi Rytkönen, Nina Zanella, Antti Nurmi, Tuulia Huhtala. Molecular, histopathologic, MRI and PET findings in syngeneic oncologic mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3041.

Theranostic multimodal potential of magnetic nanoparticles actuated by non-heating low frequency magnetic field in the new-generation nanomedicine

The scope of this review involves one of the most promising branches of new-generation biomedicine, namely magnetic nanotheranostics using remote control of functionalized magnetic nanoparticles (f-MNPs) by means of alternating magnetic fields (AMFs). The review is mainly focused on new approach which utilizes non-heating low frequency magnetic fields (LFMFs) for nanomechanical actuation of f-MNPs. This approach is compared to such traditional ones as magnetic resonance imaging (MRI) and radio-frequency (RF) magnetic hyperthermia (MH) which utilize high frequency heating AMF. The innovative principles and specific models of non-thermal magnetomechanical actuation of biostructures by MNP rotational oscillations in LFMF are described. The discussed strategy allows biodistribution monitoring in situ, delivering drugs to target tissues and releasing them with controlled rate, controlling biocatalytic reaction kinetics, inducing malignant cell apoptosis, and more. Optimization of both LFMF and f-MNP parameters may lead to dramatic improvement of treatment efficiency, locality, and selectivity on molecular or cellular levels and allow implementing both drug and drugless, i.e., pure nanomechanical therapy, in particular cancer therapy. The optimal parameters within this approach differ significantly from those used in MH or MRI because of the principal difference in the f-MNP actuation modes. It is shown that specifically designed high gradient, steady magnetic field enables diagnostic and therapeutic LFMF impact localization in the deep tissues within the area ranging from a millimeter to a few centimeters and 3D scanning of affected region, if necessary.

Monitoring of biodistribution and persistence of conditionally replicative adenovirus in a murine model of ovarian cancer using capsid-incorporated mCherry and expression of human somatostatin receptor subtype 2 gene.

A significant limiting factor to the human clinical application of conditionally replicative adenovirus (CRAd)-based virotherapy is the inability to noninvasively monitor these agents and their potential persistence. To address this issue, we proposed a novel imaging approach that combines transient expression of the human somatostatin receptor (SSTR) subtype 2 reporter gene with genetic labeling of the viral capsid with mCherry fluorescent protein. To test this dual modality system, we constructed the Ad5/3Δ24pIXcherry/SSTR CRAd and validated its capacity to generate fluorescent and nuclear signals in vitro and following intratumoral injection. Analysis of 64Cu-CB-TE2A-Y3-TATE biodistribution in mice revealed reduced uptake in tumors injected with the imaging CRAd relative to the replication-incompetent, Ad-expressing SSTR2 but significantly greater uptake compared to the negative CRAd control. Optical imaging demonstrated relative correlation of fluorescent signal with virus replication as determined by viral genome quantification in tumors. Positron emission tomography/computed tomography studies demonstrated that we can visualize radioactive uptake in tumors injected with imaging CRAd and the trend for greater uptake by standardized uptake value analysis compared to control CRAd. In the aggregate, the plasticity of our dual imaging approach should provide the technical basis for monitoring CRAd biodistribution and persistence in preclinical studies while offering potential utility for a range of clinical applications.

Monitoring of Biodistribution and Persistence of Conditionally Replicative Adenovirus in a Murine Model of Ovarian Cancer Using Capsid-Incorporated mCherry and Expression of Human Somatostatin Receptor Subtype 2 Gene

Monitoring of Biodistribution and Persistence of Conditionally Replicative Adenovirus in a Murine Model of Ovarian Cancer Using Capsid-Incorporated mCherry and Expression of Human Somatostatin Receptor Subtype 2 Gene

Molecular imaging with nanoparticles: giant roles for dwarf actors

Molecular imaging, first developed to localise antigens in light microscopy, now encompasses all imaging modalities including those used in clinical care: optical imaging, nuclear medical imaging, ultrasound imaging, CT, MRI, and photoacoustic imaging. Molecular imaging always requires accumulation of contrast agent in the target site, often achieved most efficiently by steering nanoparticles containing contrast agent into the target. This entails accessing target molecules hidden behind tissue barriers, necessitating the use of targeting groups. For imaging modalities with low sensitivity, nanoparticles bearing multiple contrast groups provide signal amplification. The same nanoparticles can in principle deliver both contrast medium and drug, allowing monitoring of biodistribution and therapeutic activity simultaneously (theranostics). Nanoparticles with multiple bioadhesive sites for target recognition and binding will be larger than 20 nm diameter. They share functionalities with many subcellular organelles (ribosomes, proteasomes, ion channels, and transport vesicles) and are of similar sizes. The materials used to synthesise nanoparticles include natural proteins and polymers, artificial polymers, dendrimers, fullerenes and other carbon-based structures, lipid-water micelles, viral capsids, metals, metal oxides, and ceramics. Signal generators incorporated into nanoparticles include iron oxide, gadolinium, fluorine, iodine, bismuth, radionuclides, quantum dots, and metal nanoclusters. Diagnostic imaging applications, now appearing, include sentinal node localisation and stem cell tracking.

Organ Selective Delivery Using a Tissue-Directed Sreptavidin-Biotin System: Targeting 5-Fluorouridine via TNP-Streptavidin

Trinitrophenyl (TNP) modification of streptavidin (St) resulted in high and prolonged accumulation in mouse liver following intravenous administration of radioiodinated TNP streptavidin (TNP-St). Uptake, which is correlated with increased TNP substitution, was first observed at 2-3 h, increased to 40-50% of injected dose/gram tissue (%/g) at 24 h and slowly declined later on. A low degree of accumulation (10%/g) was observed in the spleen. TNP substitution of other proteins such as bovine serum albumin (BSA) or ovalbumin (Ova) led to a transient short-term liver uptake. The enzyme-resistance property of streptavidin and its biotin binding sites render TNP-modified streptavidin a potential targeting vehicle to the liver. 5-Fluorouridine (FUR) was attached to high molecular weight carrier carboxymethyldextran (CMdex, derived from 40 kDa dextran) and the dextran-FUR conjugate was charged with 2-4 biotinyl groups (in the form of biotinyl-diaminopropionyl-tyrosine, BDT) for complexing to TNP-St. Biodistribution monitoring of the BDT-CMdex-FUR ligand, radiolabeled at the tyrosyl residue of BDT and targeted via non-radiolabeled TNP-St, showed that ligand accumulation in the liver was similar to TNP-St itself. Liver targeting of FUR was demonstrated by trace-labeling FUR with its structural analog 5,6-[3H]uridine prior to conjugation to dextran hydrazide. Specific liver accumulation of [3H] radioactivity occurred following administration of the conjugate only when complexed to TNP-St. Hepatic levels of [3H] radioactivity were in the range of 25%/g or 35% per whole liver during a period of at least 8h, as compared to the rapid elimination of free FUR + [3H]uridine (4%/g at 20 min). [3H]-drug radioactivity disappeared at a faster rate as compared to 125I-dextran radioactivity, suggesting that metabolic processes required to generate the 5,6-[3H]uracil-containing active metabolites took place.