428 Development of an Oncolytic Adenovirus to Treat Metastatic Colorectal Cancer

OBJECTIVES/GOALS: Colorectal cancer (CRC) is a leading cause of cancer mortality, and many patients will develop metastatic disease at some point during their treatment course. Conventional therapies such as surgery, chemotherapy, and radiation are often of limited effectiveness in these advanced stages, which necessitates the development of novel therapies. METHODS/STUDY POPULATION: Our group has designed an oncolytic adenovirus backbone structure expressing the sodium iodide symporter (NIS) which can be used in conjunction with radioiodine to facilitate cancer imaging and therapy. Using multiple CRC cell lines, oncolytic adenoviruses with different fibers were tested in vitro to determine which of these modifications yielded the highest binding to the cancer cells. Additionally, multiple promoter structures are being tested to determine the impact on the replication and oncolytic effect of the virus. Furthermore, the potential of adenovirus-mediated NIS expression to facilitate PET/CT imaging and therapy with I-131 will be explored. RESULTS/ANTICIPATED RESULTS: The Ad5/3 chimeric fiber modification demonstrated the best binding in CRC cell lines. Additionally, tissue specific promoters are employed in oncolytic viruses to confer selective replication in cancer cells, while minimizing off target effects in nearby normal tissues. We have employed a Cox2 promoter, which has demonstrated an excellent oncolytic effect. In vitro NIS expression was shown in multiple CRC cell lines through immunostaining. Small animal PET/CT imaging demonstrated signal uptake in mice with subcutaneous CRC tumors after virus and radioiodine (I-124) administration. We anticipate that future studies employing radioactive iodine (I-131) in combination with our oncolytic virus will yield an augmented antitumor effect. DISCUSSION/SIGNIFICANCE: The NIS-expressing adenovirus has the ability to support radionuclide-based imaging and therapy for CRC. With additional pre-clinical testing, our adenovirus construct has the potential to bring NIS-based therapeutics to the bedside to positively impact CRC patient care outcomes.