Use of positron emission tomography to target prostate cancer gene therapy by oncolytic herpes simplex virus

A bispecific antibody (ScBsAbAgn-2/TSPO) target for Ang-2 and TSPO resulted in therapeutic effects against glioblastomas

Antibody-based targeted therapy of cancers requires the antibody targeting of specific molecules inducing tumor cells apoptosis or death. Angiopoietin-2 (Agn-2) and translocator protein (TSPO) are identified as potential target molecules for glioblastoma therapy. The single chain anti-Agn-2 antibody (Anag-2) and anti-TSPO antibody (ATSPO) were obtained by monoclonal antibody screening. In the present study, for specific targeting and killing, we generated a recombinant bispecific antibody comprising a single-chain Fragment variable (ScFv) of anti-human Agn-2 and anti-human TSPO (ScBsAbAgn-2/TSPO), which is the mediator for mitochondrial apoptosis and tumor angiogenesis. In vitro, ScBsAbAgn-2/TSPO simultaneously bounded to both targets with a high antigen-binding affinity to Anag-2 and TSPO compared to the individual antibody. The higher expression of Ang-2 and TSPO was observed in bevacizumab-treated glioblastoma compared to normal rat brain endothelium. We also observed apoptosis-mediated cytotoxicity was improved, which resulted in the elimination of up to 90% of the target cells within 72 h. ScBsAbAgn-2/TSPO inhibited tumor growth, decreased vascular permeability, led to extended survival, improved pericyte coverage, depletion of tumor-associated macrophages, and increased numbers of intratumoral T lymphocytes infiltration in a murine bevacizumab-treated glioblastoma model. These findings were also confirmed ex vivo using glioblastoma cells from bevacizumab-treated rats with glioblastoma. We conclude that ScBsAbAgn-2/TSPO targeting of glioblastoma cell lines can be achieved in vitro and in vivo that the efficient elimination of glioblastoma cells supports the potential of ScBsAbAgn-2/TSPO as a potent, novel immunotherapeutic agent.

In vivo positron emission tomography imaging using the sodium iodide symporter as a reporter gene

Information regarding the biodistribution and kinetics of spread of oncolytic viruses is crucial for safety considerations in the design of future, more efficient reagents. Although optical imaging can be used to gain this information in rodent models, imaging with radioactive isotopes presents the advantage of being directly applicable to humans, and preclinical imaging data can provide a basis for the design of clinical protocols. In this chapter, we describe the use of the Na/I symporter as a reporter gene, associated with (124)I-NaI as a radiotracer, to monitor the anatomical localization, as well as the propagation, of oncolytic viruses using dedicated, preclinical positron emission tomography scanners.

Prostate cancer

Prostate cancer is biologically and clinically a heterogeneous disease and its imaging evaluation will need to be tailored to the specific phases of the disease in a patient-specific, risk-adapted manner. We first present a brief overview of the natural history of prostate cancer before discussing the role of various imaging tools, including opportunities and challenges, for different clinical phases of this common disease in men. We then review the preclinical and clinical evidence on the potential and emerging role of positron emission tomography with various radiotracers in the imaging evaluation of men with prostate cancer.

A fusion PET-MRI system with a high-resolution research tomograph-PET and ultra-high field 7.0 T-MRI for the molecular-genetic imaging of the brain

We have developed a positron emission tomography (PET) and magnetic resonance imaging (MRI) fusion system for the molecular-genetic imaging (MGI) of the in vivo human brain using two high-end imaging devices: the HRRT-PET, a high-resolution research tomograph dedicated to brain imaging on the molecular level, and the 7.0 T-MRI, an ultra-high field version used for morphological imaging. HRRT-PET delivers high-resolution molecular imaging with a resolution down to 2.5 mm full width at half maximum (FWHM), which allows us to observe the brain's molecular changes using the specific reporter genes and probes. On the other front, the 7.0 T-MRI, with submillimeter resolution images of the cortical areas down to 250 mum, allows us to visualize the fine details of the brainstem areas as well as the many cortical and subcortical areas. The new PET-MRI fusion imaging system will provide many answers to the questions on neurological diseases as well as cognitive neurosciences. Some examples of the answers are the quantitative visualization of neuronal functions by clear molecular and genetic bases, as well as diagnoses of many neurological diseases such as Parkinson's and Alzheimer's. The salient point of molecular-genetic imaging and diagnosis is the fact that they precede the morphological manifestations, and hence, the early and specific diagnosis of certain diseases, such as cancers.