Differential Kat3 Coactivator Usage Regulates Brain Metabolism and Neuronal Differentiation.

Introduction: Our previous work has demonstrated significant effects on the oxidative stress response, mitochondrial function, and oxidative phosphorylation in the livers and intestines of p300 S89A knockin (S89AKI) mice. We now show that this mutation is also associated with brain metabolic defects and neuronal differentiation.

Methods: p300 S89A edited P19 cells, and S89AKI mice demonstrated metabolic and neuronal differentiation defects based on proteomic, cell biological and PET imaging studies.

Biodistribution of Intra-Arterial and Intravenous Delivery of Human Umbilical Cord Mesenchymal Stem Cell-Derived Extracellular Vesicles in a Rat Model to Guide Delivery Strategies for Diabetes Therapies.

Umbilical cord mesenchymal stem cell-derived extracellular vesicles (UC-MSC-EVs) have become an emerging strategy for treating various autoimmune and metabolic disorders, particularly diabetes. Delivery of UC-MSC-EVs is essential to ensure optimal efficacy of UC-MSC-EVs. To develop safe and superior EVs-based delivery strategies, we explored nuclear techniques including positron emission tomography (PET) to evaluate the delivery of UC-MSC-EVs in vivo.

Role of theranostics in thoracic oncology.

Theranostics is a re-emerging field of medicine that aims to create targeted agents that can be used for diagnostic and/or therapeutic indications. In the past, theranostics has been used to treat neoplasms, such as thyroid cancer and neuroblastomas. More recently, theranostics has seen a resurgence with advent of new therapeutic antibodies and small molecules which can be transformed into Theranostic agents through radioconjugating with a radioactive isotope.

Preclinical PET Imaging of NTSR-1-Positive Tumors with Cu- and Ga-DOTA-Neurotensin Analogs and Therapy with an Ac-DOTA-Neurotensin Analog.

The aim of the study was to perform PET imaging and radiotherapy with a novel neurotensin derivative for neurotensin receptor 1 (NTSR-1)-positive tumors in an animal model. A di-DOTA analog of NT(6-13) with three unnatural amino acids was synthesized and radiolabeled with either Cu or Ga and tested for serum stability and tumor imaging in mice bearing NTSR-1-positive PC3, and HT29 xenografts. A dose-response therapy study was performed with 18.

TAG-72-Targeted α-Radionuclide Therapy of Ovarian Cancer Using Ac-Labeled DOTAylated-huCC49 Antibody.

Radioimmunotherapy, an approach using radiolabeled antibodies, has had minimal success in the clinic with several β-emitting radionuclides for the treatment of ovarian cancer. Alternatively, radioimmunotherapy with α-emitters offers the advantage of depositing much higher energy over shorter distances but was thought to be inappropriate for the treatment of solid tumors, for which antibody penetration is limited to a few cell diameters around the vascular system. However, the deposition of high-energy α-emitters to tumor markers adjacent to a typical leaky tumor vascular system may have large antitumor effects at the tumor vascular level, and their reduced penetration in normal tissue would be expected to lower off-target toxicity.

Improved targeting of an anti-TAG-72 antibody drug conjugate for the treatment of ovarian cancer.

Introduction: Ovarian cancer has only a 17% 5-year survival rate in patients diagnosed with late stage disease. Tumor-associated glycoprotein-72 (TAG72), expressed in 88% of all stages of ovarian cancer, is an excellent candidate for antibody-targeted therapy, as it is not expressed in normal human adult tissues, except in the secretory endometrium.

Methods: Using the clinically relevant anti-TAG72 murine monoclonal antibody CC49, we evaluated antibody drug conjugates (ADCs) incorporating the highly potent, synthetic antimitotic agent monomethylauristatin E (MMAE).

Potent immunomodulatory effects of an anti-CEA-IL-2 immunocytokine on tumor therapy and effects of stereotactic radiation.

While anti-CEA antibodies have no direct effect on CEA-positive tumors, they can be used to direct potent anti-tumor effects as an antibody-IL-2 fusion protein (immunocytokine, ICK), and at the same time reduce the toxicity of IL-2 as a single agent. Using a fusion protein of humanized anti-CEA with human IL-2 (M5A-IL-2) in a transgenic murine model expressing human CEA, we show high tumor uptake of the ICK to CEA-positive tumors with additional lymph node targeting. ICK treated CEA-positive tumors exhibit significant tumor eradication.

Antibody Targeted PET Imaging of Cu-DOTA-Anti-CEA PEGylated Lipid Nanodiscs in CEA Positive Tumors.

Lipid nanodiscs (LNDs), comprising a phospholipid bilayer encircled by two molecules of a recombinant membrane scaffold protein, can be targeted to tumors with covalently attached antibodies (Abs) or their fragments. Antibody attachment to click chemistry based PEGylated lipids on LNDs including DOTA allowed PET imaging with the positron emitter Cu. Carcinoembryonic antigen (CEA) positive tumors in CEA transgenic mice were chosen as a tumor target.

ImmunoPET, [Cu]Cu-DOTA-Anti-CD33 PET-CT, Imaging of an AML Xenograft Model.

Purpose: Acute myeloid leukemia (AML) is a highly aggressive form of leukemia, which results in poor survival outcomes. Currently, diagnosis and prognosis are based on invasive single-point bone marrow biopsies (iliac crest). There is currently no AML-specific noninvasive imaging method to detect disease, including in extramedullary organs, representing an unmet clinical need.

Generation of dual specific bivalent BiTEs (dbBIspecific T-cell engaging antibodies) for cellular immunotherapy.

Background: Bispecific T-cell engaging antibodies (BiTES), comprising dual anti-CD3 and anti-tumor antigen scFv fragments, are important therapeutic agents for the treatment of cancer. The dual scFv construct for BiTES requires proper protein folding while their small molecular size leads to rapid kidney clearance.

Methods: An intact (150 kDa) anti-tumor antigen antibody to CEA was joined in high yield (ca.

Improved antibody-guided surgery with a near-infrared dye on a pegylated linker for CEA-positive tumors.

Real-time intraoperative image-guided cancer surgery promises to improve oncologic outcomes. Tumor-specific antibodies conjugated with near-infrared (NIR) fluorophores have demonstrated the potential to enhance visualization of solid tumor margins and metastatic disease; however, multiple challenges remain, including improvement in probe development for clinical utility. We have developed an NIR-IR800 dye on a PEGylated linker (sidewinder) conjugated to the humanized anti-carcinoembryonic antigen (CEA) antibody (M5A) with extended in vivo serum and tumor persistence.

Evaluation of [Ga]DO3A-VS-Cys-Exendin-4 as a PET Probe for Imaging Human Transplanted Islets in the Liver.

[Ga]DO3A-VS-Cys-Exendin-4, a glucagon-like peptide 1 receptor agonist, was evaluated as a potential PET tracer for the quantitation of human islets transplanted to the liver. The short-lived PET radionuclide Ga, available on a regular basis from a Ge/Ga generator, is an attractive choice. Human C-peptide was measured to evaluate human islet function post-transplantation and prior to microPET imaging.

Prototype Small-Animal PET-CT Imaging System for Image-guided Radiation Therapy.

Molecular imaging is becoming essential for precision targeted radiation therapy, yet progress is hindered from a lack of integrated imaging and treatment systems. We report the development of a prototype positron emission tomography (PET) scanner integrated into a commercial cone beam computed tomography (CBCT) based small animal irradiation system for molecular-image-guided, targeted external beam radiation therapy. The PET component consists of two rotating Hamamatsu time-of-flight PET modules positioned with a bore diameter of 101.

PET of Adoptively Transferred Chimeric Antigen Receptor T Cells with Zr-Oxine.

Chimeric antigen receptor (CAR) T cell therapy is a promising clinical approach for reducing tumor progression and prolonging patient survival. However, improvements in both the safety and the potency of CAR T cell therapy demand quantitative imaging techniques to determine the distribution of cells after adoptive transfer. The purpose of this study was to optimize Zr-oxine labeling of CAR T cells and evaluate PET as a platform for imaging adoptively transferred CAR T cells.

Copper 64-labeled daratumumab as a PET/CT imaging tracer for multiple myeloma.

As a growing number of patients with multiple myeloma (MM) respond to upfront therapies while eventually relapsing in a time frame that is often unpredictable, attention has increasingly focused on developing novel diagnostic criteria to also account for disease dissemination. Positron emission tomography/computed tomography (PET/CT) is often used as a noninvasive monitoring strategy to assess cancer cell dissemination, but because the uptake of the currently used radiotracer 18fluorodeoxyglucose (F-FDG) is a function of the metabolic activity of both malignant and nonmalignant cells, the results frequently lack sufficient specificity. Radiolabeled antibodies targeting MM tissue may detect disease irrespective of cell metabolism.

Synthesis, Positron Emission Tomography Imaging, and Therapy of Diabody Targeted Drug Lipid Nanoparticles in a Prostate Cancer Murine Model.

The blood clearance of chemotherapeutic drugs such as doxorubicin (Dox) can be extended by incorporation into lipid nanoparticles (LNPs) and further improved by tumor targeting with antibody fragments. We used positron emission tomography (PET) imaging in a murine prostate cancer model to evaluate tumor targeting of LNPs incorporating Dox and antiprostate-specific membrane antigen (PSMA) diabodies. Dox-LNPs were generated by mixing or covalent attachment to water soluble distearoylphosphatidyl ethanolamine-polyethylene glycol (DSPE-PEG).

Diagnostic PET Imaging of Mammary Microcalcifications Using Cu-DOTA-Alendronate in a Rat Model of Breast Cancer.

The development of improved breast cancer screening methods is hindered by a lack of cancer-specific imaging agents and effective small-animal models to test them. The purpose of this study was to evaluate Cu-DOTA-alendronate as a mammary microcalcification-targeting PET imaging agent, using an ideal rat model. Our long-term goal is to develop Cu-DOTA-alendronate for the detection and noninvasive differentiation of malignant versus benign breast tumors with PET.

PET imaging of Cu-DOTA-scFv-anti-PSMA lipid nanoparticles (LNPs): Enhanced tumor targeting over anti-PSMA scFv or untargeted LNPs.

Introduction: Single chain (scFv) antibodies are ideal targeting ligands due to their modular structure, high antigen specificity and affinity. These monovalent ligands display rapid tumor targeting but have limitations due to their fast urinary clearance.

Methods: An anti-prostate membrane antigen (PSMA) scFv with a site-specific cysteine was expressed and evaluated in a prostate cancer xenograft model by Cu-64 PET imaging.

A series of anti-CEA/anti-DOTA bispecific antibody formats evaluated for pre-targeting: comparison of tumor uptake and blood clearance.

A series of anti-tumor/anti-chelate bispecific antibody formats were developed for pre-targeted radioimmunotherapy. Based on the anti-carcinoembryonic antigen humanized hT84.66-M5A monoclonal antibody and the anti-DOTA C8.