Poster Session – Animal Models, Thursday 1 December 2016 levels coincide with enhanced Imprime-induced immune activation and correspond with enhanced clinical responsiveness. These data support the use of pre-treatment ABA levels to select patients for Imprime-based therapy. Conflict of interest: Ownership: All authors are employees of Biothera Pharmaceuticals, Inc. Corporate-sponsored Research: All research was supported by Biothera Pharmaceuticals, Inc.
Animal Models 322 Poster (Board P001) ADAMTS18 inhibits colitis and colitis-associated colon cancer: Evidence from ADAMTS18 deficient mice T. Lu1 , Y. Wang1 , J. Tang1 , T. Hong1 , Y. Zhou1 , S. Dang2 , W. Zhang1 . 1 East China Normal University, Key Laboratory of Brain Functional Genomics, Shanghai, China; 2 Shanghai Jiao Tong University School of Medicine, Department of Biochemistry and Molecular Cell Biology, Shanghai, China ADAMTS18 (a disintegrin and metalloproteinase with thrombospondin motif 18) is a member of ADAMTS family that is known for their crucial role in development, inflammation, cancer, and vascular biology. ADAMTS18 gene was found inactivated via methylation in many tumor cell lines and carcinoma specimens, and is therefore proposed as a tumor suppressor gene (Oncogene 26: 7490, 2007). Clinically, mutation of ADAMTS18 is strongly associated with colorectal cancer (CRC). (Science 314: 268, 2006). However, a more detailed knowledge about how ADAMTS18 exerts its effect on CRC progression remains largely unclear. Here, we generate ADAMTS18 knock-out (KO) mouse and investigate the role of ADAMTS18 in CRC progression. In carcinogen azoxymethane (AOM)-induced colorectal tumor model, there were no significant differences in tumor phenotypes between wild-type (WT) and KO mice. While combined use of inflammatory agent dextran sulfate sodium (DSS) with AOM, KO mice demonstrated higher colon cancer incidence rates, more tumor numbers and severe dysplastic scores than WT mice (tumor incidence rates, WT vs. KO, 71% vs. 100%; tumor numbers, WT vs. KO, 1.5±1 vs. 6.5±1.9; P = 0.0026). ADAMTS18 KO tumor cells showed more BrdU incorporation than WT tumor cells. The results from in situ TUNEL assay showed ADAMTS18 KO tumor cells underwent less apoptosis than WT tumor cells. In DSS-induced colitis model, ADAMTS18 KO mice showed more body weight loss than widetype (WT) mice after induction with DSS. The lengths of colons were shorter in KO mice than in WT mice. Histological analysis showed that KO mice displayed more severe intestinal inflammatory infiltration and mucosa congestion than WT mice. The results of sandwich ELISA revealed that serum levels of both LPS and TNF-a were significantly elevated in KO mice compared to those in WT mice (LPS, WT vs. KO, 8.7±1.8 vs. 11.2±2.4 u/L, P = 0.044; TNF-a, WT vs. KO, 260.4±51.8 vs. 332.1±69.4 ng/L, P = 0.049). Mechanistic studies revealed that both p38MAPK and ERK1/2 were significantly activated in colitis and CRC tissues of KO mice compared to those of WT control, which are crucial regulators of cell proliferation, apoptosis and the inflammation response. Furthermore, MAPK activity in ADAMTS18 KO mice is associated with the upstream RhoA/ROCK (Rhoassociated coiled-coil containing protein kinase, monitored by MyPT1and MLC) signaling pathway, which breaks down cell-cell junction, increases intestinal permeability, promotes LPS entry and subsequent MAPK activation. Collectively, our findings indicated that ADAMTS18 plays a crucial protective role in the development of colitis-associated colon cancer, which holds promise to design new therapies for the treatment of colorectal cancer. No conflict of interest. 323 Poster (Board P002) Patient-derived xenografts (PDX) from agressive haematological malignancies B. Brzezicha1 , A. Siegert1 , W. Walther1 , I. Fichtner1 , J. Hoffmann1 , L. Karawajew2 , C. Schmitt3 , M. Janz4 . 1 EPO GmbH Berlin, preclinical oncology, berlin, Germany; 2 Experimental and Clinical Research Center ´ Universitatsmedizin ¨ Charite, Berlin, Pediatric Oncology/Hematology, ´ Universitatsmedizin ¨ Berlin CVK, and Berlin, Germany; 3 Charite, Max-Delbruck-Center ¨ for Molecular Medicine, Hematology, Oncology, and Tumor Immunology, Berlin, Germany; 4 Max Delbrueck Center for ´ University Hospital Berlin, Campus Molecular Medicine and Charite, Benjamin Franklin, Charite´ Centrum Tumormedizin CC14 Medizinische ¨ Klinik mit Schwerpunkt Hamatologie und Onkologie, Berlin, Germany Aggressive B-cell lymphomas and acute myeloid leukaemia’s (AML) constitute a substantial proportion of human haematological malignancies and
Poster abstracts S107 pose an important clinical challenge. Given the fact that these lymphomas and leukaemia’s frequently develop resistance to chemotherapy and are associated with high relapse rates, new targeted therapeutic strategies are in the focus of current research. Pre-clinical PDX models are a valuable tool to understand the molecular biology of the diseases and to evaluate new treatment approaches. Here we report the development of new PDX models from patients with aggressive lymphomas and leukaemia’s. Samples from aggressive NHLs came from the peripheral blood, lymph node extirpation or fine needle biopsies. We successfully established subcutaneous PDX models from these tumours by using immune-deficient NOG mice. Established tumours were subsequently passaged via the same route to NMRI nu/nu mice. At least after five passages, the patient-derived lymphoma models were treated with standard-of-care first line compounds such as cyclophosphamide, vincristine and rituximab (an antibody targeted against CD20, a surface antigen expressed on B-cells) as well as compounds for the second line treatment, such as gemcitabine. Three out of four NHLPDX expressed CD20 as determined by immunohistochemistry; however two of them did not show any measurable effect under rituximab treatment. Samples for the development of AML PDX models were mainly derived from plasmapheresis. The fraction of CD45+ AML cells were either transplanted s.c. or i.v. Whereas several AML cell transplants developed fast growing s.c. lesions, after i.v. transplantation, a slow systemic engraftment was observed in some models. First CD45+ human leukemic cells were measured in the peripheral blood of the mice after 14 days. The number increased up to day 70. These models have then been used to evaluate different systemic treatments. Response could be determined by measurement of CD45+ AML cells in the blood. Data from drug sensitivity screening to SoC drugs will be presented. All together we have 12 new PDX models from B-cell lymphomas and acute myeloid leukaemia’s established. This exceptional panel of broadly characterized PDX models from aggressive and treatment resistant diseases provides a new platform for translational oncology research projects, the identification and validation of new targets and biomarker candidates, screening of new drugs and combinations, as well as for personalizing patient treatment. No conflict of interest. 324 Poster (Board P003) Transcriptome-based network analysis of the human xenograft tumor–mouse stroma compartments J. Xue1 , W. Qian1 , S. Guo1 , J. Cai1 , H. Li1 . 1 Crown Bioscience, Translational Oncology, Santa Clara, USA Background: Tumor microenvironment plays critical roles in tumor growth/progression and response to pharmaceutical. However, investigating stroma-specific components is rather challenging for the difficulty to separate stroma from tumor cells, either physically via microdissection or in silico via bioinformatics. Patient derived xenograft (PDX), where human tumor and mouse stroma can readily be separated in silico [1], provides a model to study tumor microenvironment, including tumor–stroma interactions. Methods: Whole transcriptome sequencing reads on a cohort of 872 subcutaneous PDXs in athymic mice [2] were aligned to human and mouse genomes to discriminate human cancer and mouse stroma content respectively [2]. Low expressed/less variable genes were removed across the two components. The gene expression profiles of 35 cell types (including endothelia, fibroblast and leukocyte) from Immunological Genome Consortium (ImmGen) [2] were used to create lineagespecific signatures and compute relative fractions of each cell type by CIBERSORT [3] in the stroma composition. Weighted gene co-expression network analysis (WGCNA) [4] was applied on human and mouse gene expression data respectively to identify distinct gene modules associated with different biological functions. Human-mouse gene correlation analysis was performed to construct cross-species expression networks. Results: The average mouse-to-human read ratio is 11.14%, consistent with the report [2]. Deconvolution of mouse gene expression identified various fractions of stromal cells, including immune cells. The fractions vary across cancers: e.g. fibroblasts ranges from ~10% to ~25%, T-CD4+ memory lymph node consists about 20% of stroma in lymphoma. The existence of large fraction of monocytes (>20%), tissue resting lymphocytes, and low amount of tumor-associated macrophages (~3%) suggested weak non-T immune interactions across species. Distinct co-expressed gene modules from human (50x) and mouse (28x) were determined by WGCNA, revealing that human clusters were more correlated to cancer type than mouse clusters, particularly strong in pancreatic, colorectal and lung cancers. Knowledge-based functional analysis of these gene modules revealed the association of diverse biological processes. In addition, crossspecies correlation network identified novel relationship between human and mouse genes over all PDXs and in specific cancers. For example, human transcriptional regulator ZBED6, affecting cell cycle/CRC-growth [5],