Research Team: Paloma H. Giangrande and Judy Lieberman (Children’s Hospital Boston)
The following three specific aims are proposed:
Elucidate the mechanism of action of A9g, an in vivo-optimized RNA aptamer to prostate specific membrane antigen (PSMA).
Determine the minimum effective dose (MED) and maximum tolerated dose (MTD) of A9g in mice.
Develop and characterize RNA smart drugs capable of simultaneously inhibiting PSMA activity and delivering therapeutic siRNAs to prostate cancer cells.
The proposed studies will be performed by a team of four highly accomplished female investigators with synergistic and complementary backgrounds and expertise in PSMA biology (Dr. Leslie Caromile – junior investigator), tumor angiogenesis (Dr. Linda Shapiro), mouse models of prostate cancer (Dr. Christina Jamieson) and RNA therapeutics and smart drug technology (Dr. Paloma Giangrande). The combined contribution of our team is expected to be the development, optimization and thorough preclinical testing of two novel RNA smart drugs for the prevention/treatment of bone metastatic prostate cancer. This contribution is significant because it provides critical endpoints that will enable the timely translation of these novel RNA smart drugs for advanced stage prostate cancer, and thus constitutes critical progress towards addressing an unmet need in cancer medicine. Towards this end, we anticipate that one or both of these drugs will be tested in humans within the next five years.
We propose the following two specific aims:
Evaluate SMC-specific RNA aptamers in cultured SMCs and in animal models of vascular injury. Proposed studies will evaluate SMC-specific aptamers for their ability to inhibit SMC migration and proliferation in vitro, identify cell surface target(s) and signaling pathways involved in the effects of aptamers, and optimize binding, specificity and serum stability of aptamers in vitro. In addition, proposed studies will optimize delivery to injured vessels, define pharmacokinetics/pharmacodynamics (PK/PD), and assess the therapeutic efficacy of SMC-specific aptamers in vivo using complementary models of vascular disease.
Test the ability of the SMC-specific aptamers to deliver a therapeutic load (RNAi modulators) to SMCs in vitro and in animal models of vascular disease. Experiments will optimize uptake and cellular processing (endocytosis, endosomal release, RNAi processing) and serum stability of chimeras, define biodistribution, PK/PD and safety profile, and evaluate the efficacy of chimeras in vivo for attenuation of vascular disease. The proof-of-concept studies described are innovative because they represent the first thorough preclinical assessment of cell-targeted RNA therapies to be evaluated for efficacy and safety in future clinical trials in patients with CVD.
Furthermore, the successful completion of these studies will provide vital information on safety and delivery of RNA reagents in vivo and result in a foundation for the development of similar cell-targeted approaches for multiple diseases.
Research Team: Paloma H. Giangrande and Francis J. Miller (Cardiology, Duke University Medical Center)
Novel diagnostic methods for characterizing the cellular and molecular makeup of metastatic breast cancer on an individualized basis (i.e., personalized medicine) have been intensively pursued in recent years due to the heterogeneity of this disease. The number of circulating tumor cells (CTCs) in cancer patients has recently been shown to be a valuable (and non-invasively accessible) diagnostic indicator of the state of metastatic breast cancer. In particular, patients with no CTCs were found to have a better overall prognosis compared to CTC-positive patients. However, the accuracy and ease-of-operation of available CTC tests remains unsatisfactory. Our proposal aims to develop a rapid and highly-sensitive CTC detection assay based on the development of chemically-modified, nuclease-activated probes that are specifically digested (i.e., activated) by target nucleases expressed in breast cancer cells. The successful outcome of the proposed work will provide a robust assay for detection of CTCs that will be straightforward to implement in most clinical diagnostic labs.
Research Team: Paloma H. Giangrande, James O. McNamara (University of Iowa), Alexandra Thomas (Univeristy of Iowa) and Howard Ozer (University of Illinois Cancer Center)
Despite surviving major nonthoracic trauma or burns, there is a high morbidity and mortality associated with the subsequent development of multiple organ dysfunction syndrome (MODS), the lungs being the most commonly affected organ, often resulting in acute respiratory distress syndrome (ARDS) with a mortality of ~50%. There are currently only supportive treatments for MODS and ARDS. In response to cell death, histones are released from the cell nucleus into the circulation where they amplify tissue injury by killing other cells, activating Toll-like receptors, and activating platelets. Importantly, circulating histone levels are associated with mortality in humans with MODS/ARDS. We propose to identify RNA aptamers to specifically target circulating histones in order to prevent their toxic effects and reduce the morbidity and mortality of multiple organ dysfunction associated with trauma, burns, sepsis, and inhalation injury. RNA aptamers are single-stranded nucleic acids whose binding properties depend on their sequence and structure. Aptamers have high binding affinity and specificity with significant advantages over other biologics, including stability at room temperature, resistance to serum degradation, and minimal immunogenicity. Our studies will use an in vitro selection technique SELEX (Systemic Evolution of Ligands by Exponential enrichment) to isolate high affinity RNA aptamers against human histones and then test efficacy and safety in animal models of MODS. This application is innovative and high risk with the potential for paradigm shifting and high reward in the treatment of MODS and ARDS.
Research Team: Paloma H. Giangrande, Francis J. Miller (Cardiology, Duke University Medical Center), Alejandro Comellas (University of Iowa) and Julia Klesney-Tait (University of Iowa)