Abstract 4211: Discovery of a novel peptide for improvement of radiotherapeutic efficacy and development of prognotic diagnosis

Cancer can be treated by the various modalities including surgery, chemotherapy, radiotherapy, among which the radiotherapy is the most important therapeutics in the cancer treatment. Despite the progression of modalities, cancer therapy has been constrained by impasse of prediction of treatment outcome and direction of cancer therapeutics because of diagnosis date, metastasis and genetic diversity of the individual patients. In this study, we discovered specific tumor targeting peptides and radiotherapy-responding peptides suitable to apply to cancer therapy and monitoring of radiotherapy response. For a non-invasive imaging for potential cancer diagnosis system, we screened peptides using the phage display technique. Phage display is used in various pharmaceutical biotechnologies, and the one of the most powerful technologies to identify novel peptides regulating carcinogenesis. To emphasize the function of peptide ligands in a living body and consider the tumoral microenvironment, we used the patient-derived xenograft (PDX) tumor models for in vivo peptide displayed phage screening. It is warranted that the peptides specifically targeting in vivo human cancer xenografts with radiation treatment or not in colorectal cancer PDXs. We performed in vivo peptide screening in the two different cases of colorectal cancer PDX mouse models, and selected peptides were confirmed to radiation responding peptides and radiation resistant peptides. The results suggested that selected peptides were a promising diagnostic lead molecule for rapid and accurate detection for the radiotherapy response. Taken together, we described a strategy to identify the peptides by in vivo phage display, and peptides possessed the specific targeting ability which would be potentially feasible for the development of personalized precision treatment. Its might be potential IR-guided probe and prognostic diagnosis in radiotherapy for colorectal cancer. Keywords: Peptide, Colorectal cancer, Patient-derived xenograft (PDX), Radiation, In vivo peptide screening Citation Format: Kyoung Jin Lee, Jae Hee Lee, Si Yeol Song, Seong-Yun Jeong, Eun Kyung Choi. Discovery of a novel peptide for improvement of radiotherapeutic efficacy and development of prognotic diagnosis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4211.