Journal Article

Cancer; tumor; in vivo imaging; cancer immunotherapies

Cancer immunotherapies can be guided by cellular imaging techniques, which can identify the presence or absence of immune cell accumulation in the tumor tissue in vivo and in real time. This review summarizes various new and evolving imaging techniques employed for tracking and monitoring of adoptive natural killer cell immunotherapies.

Journal Article

In vivo imaging; inflammation; leukocytes; rejection; transplantation; fluorescence molecular tomography; FMT; Prosense

Background: Clinical detection of transplant rejection by repeated endomyocardial biopsy requires catheterization and entails risks. Recently developed molecular and cellular imaging techniques that visualize macrophage host responses could provide a noninvasive alternative. Yet, which macrophage functions may provide useful markers for detecting parenchymal rejection remains uncertain.

Methods and Results: We transplanted isografts from B6 mice and allografts from Balb/c mice heterotopically into B6 recipients. In this allograft across major histocompatability barriers, the transplanted heart undergoes predictable progressive rejection, leading to graft failure after 1 week. During rejection, crucial macrophage functions, including phagocytosis and release of proteases, render these abundant innate immune cells attractive imaging targets. Two or 6 days after transplantation, we injected either a fluorescent protease sensor or a magnetofluorescent phagocytosis marker. Histological and flow cytometric analyses established that macrophages function as the major cellular signal source. In vivo, we obtained a 3-dimensional functional map of macrophages showing higher phagocytic uptake of magnetofluorescent nanoparticles during rejection using magnetic resonance imaging and higher protease activity in allografts than in isografts using tomographic fluorescence. We further assessed the sensitivity of imaging to detect the degree of rejection. In vivo imaging of macrophage response correlated closely with gradually increasing allograft rejection and attenuated rejection in recipients with a genetically impaired immune response resulting from a deficiency in recombinase-1 (RAG-1-/-).

Conclusions: Molecular imaging reporters of either phagocytosis or protease activity can detect cardiac allograft rejection noninvasively, promise to enhance the search for novel tolerance-inducing strategies, and have translational potential.

Journal Article

Animals; B16-F10-luc-G5 cells; Bioware; Cell Division; Cell Line, Tumor; Collagen; Humans; Injections; Male; Mice; Mice, Nude; RNA Interference; RNA Stability; RNA, Small Interfering; Testicular Neoplasms; Transduction, Genetic; Xenograft Model Antitumor Assays

Silencing gene expression by siRNAs is rapidly becoming a powerful tool for the genetic analysis of mammalian cells. However, the rapid degradation of siRNA and the limited duration of its action call for an efficient delivery technology. Accordingly, we describe here that Atelocollagen complexed with siRNA is resistant to nucleases and is efficiently transduced into cells, thereby allowing long-term gene silencing. Site-specific in vivo administration of an anti-luciferase siRNA/Atelocollagen complex reduced luciferase expression in a xenografted tumor. Furthermore, Atelocollagen-mediated transfer of siRNA in vivo showed efficient inhibition of tumor growth in an orthotopic xenograft model of a human non-seminomatous germ cell tumor. Thus, for clinical applications of siRNA, an Atelocollagen-based non-viral delivery method could be a reliable approach to achieve maximal function of siRNA in vivo.

Journal Article

FMT; in vivo imaging; ProSense; MMPSense

Eosinophils are multifunctional leukocytes that degrade and remodel tissue extracellular matrix through production of proteolytic enzymes, release of proinflammatory factors to initiate and propagate inflammatory responses, and direct activation of mucus secretion and smooth muscle cell constriction. Thus, eosinophils are central effector cells during allergic airway inflammation and an important clinical therapeutic target. Here we describe the use of an injectable MMP-targeted optical sensor that specifically and quantitatively resolves eosinophil activity in the lungs of mice with experimental allergic airway inflammation. Through the use of real-time molecular imaging methods, we report the visualization of eosinophil responses in vivo and at different scales. Eosinophil responses were seen at single-cell resolution in conducting airways using near-infrared fluorescence fiberoptic bronchoscopy, in lung parenchyma using intravital microscopy, and in the whole body using fluorescence-mediated molecular tomography. Using these real-time imaging methods, we confirmed the immunosuppressive effects of the glucocorticoid drug dexamethasone in the mouse model of allergic airway inflammation and identified a viridin-derived prodrug that potently inhibited the accumulation and enzyme activity of eosinophils in the lungs. The combination of sensitive enzyme-targeted sensors with noninvasive molecular imaging approaches permitted evaluation of airway inflammation severity and was used as a model to rapidly screen for new drug effects. Both fluorescence-mediated tomography and fiberoptic bronchoscopy techniques have the potential to be translated into the clinic.

Journal Article

Bioware; Gene Silencing; PC-3M-luc; Peptides; Proteins; RNA Interference; Transfection

RNA interference (RNAi) is an attractive phenomenon for practical use that specifically inhibits gene expression and is carried out by small double-stranded RNAs (dsRNAs) including small interfering RNA (siRNA) or short hairpin RNA (shRNA). In addition, RNAi is of great interest for clinical use to cure refractory diseases related to the expression of a specific gene. To achieve gene silencing in the body, a sufficient amount of dsRNA must be delivered and internalized into target cells. However, dsRNAs have a large molecular weight and net negative charge, which limits their membrane-permeating ability. Moreover, dsRNAs are rapidly degraded by endonucleses in the body. Therefore, for the efficient delivery of dsRNAs, many approaches based on drug delivery systems have been carried out. In this review, we focus on recent reports about the application of functional peptides and proteins designed for the efficient delivery of dsRNAs.