Abstract B38: Clinical applications of PDX/NOG models for personalized chemotherapy – possible use in chemo-sensitivity testing and clinical sequencing

Personalized medicine represents an ideal medical approach for cancer therapy. In the field of clinical oncology, personalized medicine or therapy involves the evolutionary expansion of conventional clinical approaches that progress from patient evaluation, differential diagnosis, to the treatment of diseases. A number of the complex techniques employed in personalized medicine, such as clinical genome sequencing, biochemical marker analyses, chemo-sensitivity testing, and cancer immunotherapy, require fresh, viable, and sufficient amounts of specimens for reliable estimations. Mice bearing patient-derived xenografts (PDXs) with clinical information (so-called “Cancer Xenopatients”) are remarkable systems in personalized medicine for cancer. We previously reported the rapid and efficient establishment of PDXs using NOG mice (PDX/NOG models, AACR2015 #1940, IJO 47 61-70 2015). NOG mice, NOD/Shi-scid/IL2Rγ null (NOG) mice derived from NOD/SCID mice with a common gamma chain, have multifunctional defects in natural killer cell activity, macrophage function, complement activity, and dendritic cell function in addition to the absence of functional T and B lymphocytes. NOG mice have been identified as the most appropriate immunodeficient host animal for the direct xenografting of fresh tumor tissue due to the preservation of cancer stem cells (CSCs). Fresh and valuable xenograft samples, similar to surgical samples with the preservation of CSC, are stably provided using PDX/NOG models. Moreover, human tissue (tumor) and mouse tissue (stroma) are clearly distinguished by immunohistochemical analysis or gene arrangement sequencing. In the present study, we discussed the possibility of using PDX/NOG model simulations for personalized cancer chemotherapy. We previously established 47 lines of gastrointestinal cancer xenografts. In these cases, clinical information regarding chemotherapy for donor patients was retrieved where possible. Collagen gel droplet-embedded culture-drug sensitivity tests (CD-DST) were performed on 16 lines of PDX/NOG. In 4 of these lines, CD-DST were successfully conducted on original surgical specimens. The results of CD-DST between original and PDX/NOG specimens generally correlated (R 2 =0.01-0.89). The results of CD-DST using PDX/NOG specimens were compatible with the clinical effects of anti-cancer drugs. Genome sequencing and interactome analyses, a comprehensive analysis of tumor-stroma interactions innovated by Professor Ishikawa S. at Tokyo Medical and Dental University, were also performed on mRNA from 17 lines of PDX/NOG. Our interactome analyses showed tumor-stroma interactions in PDX/NOG comprehensively and quantitatively at the gene-expression level by distinguishing gene arrangements in human tissue (tumor) from mouse tissue (stroma). The EGF-EGFR or VEGFA-KDR interactions observed closely reflected the clinical effectiveness of an EGFR inhibitor (Cetuximab) or VEGF-A inhibitor (Bevacizumab) as well as the results of in vivo chemo-sensitivity tests using PDX/NOG. The results of CD-DST and sequencing in PDX/NOG appear to be reliable for clinical simulations of chemotherapy and will definitely assist in the selection of the most sensitive anti-cancer drug for each patient. The fast and efficient establishment of individual PDXs will contribute to personalized anti-cancer therapies. Citation Format: Tsuyoshi Chijiwa, Takayuki Isagawa, Akira Noguchi, Hidemitsu Sato, Akimune Hayashi, Haruhiko Cho, Manabu Shiozawa, Takeshi Kishida, Soichiro Morinaga, Tomoyuki Yokose, Makoto Katayama, Nobuo Takenaka, Mizuha Haraguchi, Naoki Miyao, Yuichi Tateishi, Kenji Kawai, Hiroshi Suemizu, Roppei Yamada, Yoshiyasu Nakamura, Kohzoh Imai, Daisuke Komura, Shumpei Ishikawa, Masato Nakamura, Yohei Miyagi. Clinical applications of PDX/NOG models for personalized chemotherapy – possible use in chemo-sensitivity testing and clinical sequencing. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B38.