JHU/CCR Fellowship in Molecular Targets and Drug Discovery Technologies Project Details

Project Sponsor/Mentor:	Javed Khan
Title:	Principal Investigator
Address:	Advanced Technology Center, Room 134E 8717 Grovemont Circle Gaithersburg, MD 20877
Telephone:	301-435-2937
Fax:
Email:	khanjav@mail.nih.gov
Sponsoring Laboratory/Branch:	Pediatric Oncology Branch

Project Title:	Development of antisense therapeutic peptide nucle
Target(s) of Interest:	Fusion Genes PAX3-FKHR

Project Synopsis:
Cytogenetic and molecular genetic investigations over the past two decades have led to the discovery of various sarcomas characterized by specific chromosomal translocations. The fused genetic products are often responsible for encoding transcriptional factors which drive protein synthesis proliferation and growth. These transcriptional factors induce deregulated transcription activation and signaling which in most cases lead to malignancy. Among several chromosomal translocations, the PAX3-FKHR t(2:13) chimeric oncoprotein is uniqely found in alveolar rhabdomyosarcoma (ARMS). Rhabdomyosarcoma is a soft tissue tumor affecting the head, neck, arms and legs of children. This highly malignant soft-tissue tumor invades local structures and metastasizes to remote sites by lymphatic and hematogenous spread. In general transcriptional factors are undoubtedly the most challenging therapeutic targets in the traditional approach of drug discovery. The difficulty stems from their activation involves a complex multi protein-protein interaction and control numerous downstream genes. Hence the design of small molecules inhibitors against such complex interaction is a daunting task with limited chance of success. It is therefore prudent to investigate antisense/antigene therapeutic paradigm for chromosomal translocation related sarcomas. Recently siRNA and DNA based antisense oligonucleotide have attracted greater interest as therapeutic agents and several are in clinical trials. It is important however to note that, DNA and RNA molecules are prone to hydrolytic actions of nucleases and their negatively charged back bone make them hard to be internalized through the plasma membrane. To overcome such problems new class of DNA/RNA mimics known as peptide nucleic acids (PNAs) are discovered. PNAs are DNA mimics without sugar phosphate backbone. PNAs possess attractive chemical properties due to their neutral peptide backbone, hydrolytic stability, high Tm and synthetic accessibility. Since their discovery by Nielsen in 1993, PNAs have found diverse application as molecular recognition tools and hybridization probes. PNAs have been used to successfully block translation/transcription in cancer cells and have the advantage of greater stability and ease of chemical synthesis compared to RNA or DNA based therapeutics. However, development of PNAs as antisense agents in the clinics is at its early stage due to permeability and delivery problem. In this project we are proposing to develop antisense PNA against the PAX3-FKHR oncogene and efficient delivery systems based on cell penetrating peptides (CPPs), liposomal nanoparticles and homing peptides. After a successful anti PAX3-FKHR CPP-PNA conjugates screen, an in vivo study with mouse model of rhabdomyosarcoma will be pursued.
Fellow Research Plan:
Fellow Training Plan: 1. Gain hands on experience in medicinal chemistry tools, chemical biology and drug development techniques 2. Develop skills as a translational researcher 3. Understanding the biology of chromosomal translocation in the context of alveolar rhabdomyosarcoma cancers. 4. Acquire knowledge and skills in vitro and in vivo assays 5. Learn various imaging techniques 6. Participate in writing scientific manuscripts and present reports in scientific meetings 7. Exposure to multidisciplinary knowledge within the laboratory (biology, chemistry, bioinformatics and medicine)