Abstract 332: Establishment of animal model for metastasis of human lung cancers using NOJ/SCID mice

Lung cancer is the leading cause of cancer death among malignant tumors. Lymphogenic and distant metastases were found approximately 70% at the diagnosis, and most of recurrence after surgery occurs as distant metastasis. Therefore, it is important to establish the new strategy for control of metastatic lung cancers. Since metastasis consists of several steps such as loss of cell adhesion, intravasation, survival in circulation, exit into new tissues, and colonization in a distant site, a suitable animal model is indispensable for investigation of metastasis. In addition, recent investigations revealed that biological and molecular characteristics of cancer cells were different between primary and metastatic lesions, as well as among each metastatic site. To establish the animal model reflecting human metastatic lung cancers, we used NOD/Scid/Jak3null (NOJ) mice, which exhibit deficiencies in NK cell activity, macrophage and DC function, and complement activation as well as T and B cell deficiencies. This animal model enabled us to engraft various human cells more easily than previous immunodeficiency mouse models. At first, twenty kinds of human lung cancer cell lines were screened by expression pattern of E-cadherin and vimentin using western blot analysis, and two cell lines with high expression of vimentin and low expression of E-cadherin were selected. The cells (1×107/mouse) were injected into the dorsal flanks, and one cell line, H1975 showed lymphogenic metastasis to axillary and abdominal lymph nodes, resulting dissemination to pleura and diaphragm with ascites. Since H1975 cells carry epidermal growth factor receptor (EGFR) mutation, L858R and T790M, we can monitor the existence of cancer cells using a sensitive detection system, mutation-biased PCR and quenched probe system (MBP-QP), which were established in our laboratory. We have also tried to establish the animal model which lung cancer cells are inoculated into lung to mimic metastasis of human lung cancers. Using these model systems, we have been performing comprehensive analysis including mRNA expression, the mutation status of lung cancer related genes in each metastatic site, and compared the phosphorylation status of 38 kinds of molecules. Our goal of this study is to establish the animal model to reproduce phenotypes of metastasis of human lung cancers for screening of anti-metastatic agents. Citation Format: Naoko Aragane, Akemi Sato, Naomi Kobayashi, Masaru Ide, Eisaburo Sueoka, Sei