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NSG™-Quad mice, a new humanized mouse model with improved human innate immune cell development
Poster Session – Cytotoxics, Thursday 1 December 2016 the PDX. For selected PDX, orthotopic transplantation into the peritoneum revealed their potential to form tumors in kidney, ovaries and abdominal diaphragm. The chemosensitivity testing of conventional and of targeted drugs in 10 of the PM PDX models revealed heterogeneous response of the PDX, particularly for 5-FU, irinotecan, docetaxel, cetuximab, erlotinib and regorafenib. More interestingly, different responses were observed in PDX from omentum vs. peritoneum, derived from the same patient, indicating some heterogeneity within the PM. Conclusions: This PDX mouse model panel of the CRC PM can be used for further studies to test novel therapies or combinations for PM of CRC. Our results demonstrate, that this novel panel of PDX maintains the morphology of the patient tumor in early passages, reflect heterogeneous response rates, possess potential of disseminated growth in the peritoneum and can be used as preclinical in vivo platform for translational studies of potential clinical use. No conflict of interest. 342 Poster (Board P021) Establishment and characterization of a hormone dependent, PSA/PSMA positive prostate PDX model M. Wick1 , M. Quinn1 , A. Mangold1 , L. Gamez1 , A. Diaz1 , T. Vaught1 , J. Reyna2 , A. Tolcher1 , D. Rasco1 , A. Patnaik1 , K. Papadopoulos1 . 1 START, Preclinical Research, San Antonio, USA; 2 Urology SA, Oncology, San Antonio, USA Background: Preclinical xenograft models of cancer are routinely used to screen potentially useful therapies. While some tumor types have abundant models available for evaluation, few prostate cancer models are available, with even fewer representing hormone-dependent, PSA/PSMA positive prostate cancer. To address this issue we established a prostate cancer patient-derived xenograft (PDX) designated ST1273 in athymic nude mice and characterized and compared the model against cell-based prostate cancer xenografts and a second prostate cancer PDX. Materials and Methods: ST1273 was established from a primary biopsy collected from a sixty-five year old Hispanic male with prostate cancer. Receptor expression of the resulting model was determined using immunohistochemistry and mutations identified by NGS. Results were compared with the five cell-based xenograft (CBX) prostate models LNCaP, PC-3, DU145, EE06AA-hT and VCaP and a second prostate PDX designated (ST2347). In vivo studies were performed evaluating ST1273 and CBX models towards approved therapies and ST1273 towards two investigational PSMA-targeting antibody–drug conjugate (ADC) therapies. In vivo study endpoints included tumor volume and time from treatment initiation with T/C values and tumor regression reported at study completion. Results: ST1273 growth was found dependent on exogenous hormone. ST1273 and LNCaP were found to express PSMA while VCaP expressed glucocorticoid receptor (GR). ST1273 and CBX models reported variable activity towards docetaxel and the targeted therapies abiraterone and enzalutamide. Interestingly treatment with one of the ADC molecules resulted in durable tumor regressions in ST1273. Conclusion: We have established and characterized a PDX representing hormone-dependent, PSA/PSMA positive prostate cancer designated ST1273 and benchmarked it against standards of care and CBX prostate xenografts. We have also demonstrated its utility towards evaluating PSMAtargeting therapies No conflict of interest. 343 Poster (Board P022) NSG™-Quad mice, a new humanized mouse model with improved human innate immune cell development L.C. Yao1 , M. Cheng1 , L. Shultz2 , D. Greiner3 , J. Keck1 , M. Brehm3 . The Jackson Laboratory, In Vivo Pharmacology Services, Sacramento, USA; 2 The Jackson Laboratory, Cancer Center, Bar Harbor, USA; 3 University of Massachusetts Medical School, Program in Molecular Medicine, Worcester, USA 1
The JAX® Onco-Hu™ Platform utilizes CD34+ HSC humanized NSG™ and NSG™-SGM3 mice engrafted with human patient-derived xenografts and human tumor cell lines to enable the in vivo investigation of the interactions between the human immune system and human cancer. We recently have illustrated the efficacy of PD1 and CTLA-4 check-point inhibitors in both humanized mouse strains engrafted with Non-Small Cell Lung Cancer and Triple-Negative Breast Cancer tumors. A major avenue of our investigation is to increase the understanding of the role of the human immune system in the control of cancer by generating murine humanized models with a more complete hematopoietic system and robust innate immune cell population. Monocytes/macrophages and NK cells are important in tumorigenesis and are potential targets for cancer immunotherapy. The HSC humanized triple transgenic NSG™-SGM3 mice expressing three human cytokines SCF, GM-CSF, and IL-3 have more
Poster abstracts S113 robust and faster engraftment levels in myeloid and lymphoid populations compared to its NSG™ predecessor. Here we introduce a new mouse strain, the NSG™-Quad mouse, in which the fourth cytokine human CSF-1 is expressed on the NSG™-SGM3 background through the crossing of the NSG-SGM3 and NSG-CSF-1 mouse strains. This cross hopefully would further support the development and function of myeloid cells and natural killer cells derived from human CD34+ HSC cells. For the first time, we will present the hematopoietic engraftment protocol tailored for the new strain and provide a direct comparison of human immune system reconstitution in the peripheral blood of NSG™-SGM3 mice vs. NSG™-Quad recipient mice. The functions of human monocytes and NK cells in NSG™-Quad mice will be discussed including responses to inflammatory stimuli and cytotoxic activity, respectively. Lastly, we will show the growth curves of human tumor xenografts implanted in HLA partially matched human HSC engrafted NSG™-Quad mice and their potential in further understanding the immune cell and tumor environment that will hopefully lead to the development of effective novel immunotherapies No conflict of interest. 344 Poster (Board P023) Inactivation of KLF4 promotes T-cell acute lymphoblastic leukemia and activates the MAP2K7 pathway that can be targeted for therapy Y. Shen1 , C.S. Park2 , K. Suppipat3 , T.A. Mistretta2 , M. Puppi2 , T. Horton4 , K. Rabin2 , J. Meijerink5 , D. Lacorazza2 . 1 Baylor College of Medicine, Texas Children’s Hospital, Pathology & Immunology, Houston, USA; 2 Baylor College of Medicine, Pathology & Immunology, Houston, USA; 3 Chulalongkorn University, Pediatrics, Bangkok, Thailand; 4 Baylor College of Medicine, Pediatrics, Houston, USA; 5 Erasmus MC, University Medical Center Rotterdam, Pediatrics, Rotterdam, Netherlands T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive blood cancer that affects children and adults, originates from the malignant transformation of lymphoid progenitor cells and is considered to be a highrisk disease due to the poor response to treatment and increased incidence of relapse. Although relapse is the leading cause of death in children with cancer, there is no targeted therapy available for these patients to eliminate chemoresistant leukemic initiating cells (LIC). We have discovered that levels of the Kruppel-like ¨ factor 4 (KLF4), which is known to promote stemness and to reprogram somatic cells into pluripotent stem cells, are significantly low in T-ALL patients, particularly in the ETP and TLX ALL subtypes associated with poor prognosis. In contrast to normal blood cells, we found that lymphoblasts from children with T-ALL exhibit low levels of KLF4 transcripts and hypermethylation of the proximal KLF4 promoter. To study the role of KLF4 and the genetic events governing the transition from a pre-leukemic state to aggressive disease, we used a T-ALL mouse model based on the expression of the gain-of-function NOTCH1-L1601PDP mutant that has weak leukemogenic capacity and is frequently found in patients with T-ALL. Deletion of the Klf4 gene accelerated the onset and worsened disease progression by deregulating the proliferation of leukemic cells and increasing the frequency of LIC identified by limitingdose transplantation and immunophenotypic identification. A combined analysis of global gene expression and genome-wide binding revealed that KLF4 directly repressed the Map2k7 gene encoding the dual specificity mitogen-activated protein kinase 7 (Map2k7) involved in stress MAPKK pathway. Most remarkably, T-ALL cells from both Klf4D/D leukemic mice and pediatric patients displayed elevated levels of total and phosphorylated Map2k7 and subsequent activation of the downstream targets JNK, c-Jun, and ATF2. Pharmacological inhibition of activated JNK induces cytotoxicity in T-ALL cell lines, xenograft model of T-ALL, and cells from relapse T-ALL PDX, suggesting an alternative approach to treat T-ALL. Collectively, these data uncover a novel function for KLF4 by regulating the MAP2K7 pathway in T-ALL that can be targeted to eradicate leukemia-initiating cells in T-ALL patients. No conflict of interest.
Cytotoxics 345 Poster (Board P024) A site-specifically conjugated anti-CD22 antibody bearing an MDR1-resistant maytansine payload yields excellent efficacy and safety in preclinical models D. Rabuka1 , P. Drake1 , A. Carlson1 , J. McFarland1 , R. Barfield1 , S. Banos1 , W. Zmolek1 , Y. Kim1 , B. Huang1 , A. Garofalo1 , R. Kudirka1 . 1 Catalent Biologics, Chemical Biology, Emeryville, USA Background: Hematologically-derived tumors make up ~10% of all newly-diagnosed cancer cases in the U.S. Of these, the non-Hodgkin lymphoma (NHL) designation describes a diverse group of cancers that
The JAX® Onco-Hu™ Platform utilizes CD34+ HSC humanized NSG™ and NSG™-SGM3 mice engrafted with human patient-derived xenografts and human tumor cell lines to enable the in vivo investigation of the interactions between the human immune system and human cancer. We recently have illustrated the efficacy of PD1 and CTLA-4 check-point inhibitors in both humanized mouse strains engrafted with Non-Small Cell Lung Cancer and Triple-Negative Breast Cancer tumors. A major avenue of our investigation is to increase the understanding of the role of the human immune system in the control of cancer by generating murine humanized models with a more complete hematopoietic system and robust innate immune cell population. Monocytes/macrophages and NK cells are important in tumorigenesis and are potential targets for cancer immunotherapy. The HSC humanized triple transgenic NSG™-SGM3 mice expressing three human cytokines SCF, GM-CSF, and IL-3 have more
Poster abstracts S113 robust and faster engraftment levels in myeloid and lymphoid populations compared to its NSG™ predecessor. Here we introduce a new mouse strain, the NSG™-Quad mouse, in which the fourth cytokine human CSF-1 is expressed on the NSG™-SGM3 background through the crossing of the NSG-SGM3 and NSG-CSF-1 mouse strains. This cross hopefully would further support the development and function of myeloid cells and natural killer cells derived from human CD34+ HSC cells. For the first time, we will present the hematopoietic engraftment protocol tailored for the new strain and provide a direct comparison of human immune system reconstitution in the peripheral blood of NSG™-SGM3 mice vs. NSG™-Quad recipient mice. The functions of human monocytes and NK cells in NSG™-Quad mice will be discussed including responses to inflammatory stimuli and cytotoxic activity, respectively. Lastly, we will show the growth curves of human tumor xenografts implanted in HLA partially matched human HSC engrafted NSG™-Quad mice and their potential in further understanding the immune cell and tumor environment that will hopefully lead to the development of effective novel immunotherapies No conflict of interest. 344 Poster (Board P023) Inactivation of KLF4 promotes T-cell acute lymphoblastic leukemia and activates the MAP2K7 pathway that can be targeted for therapy Y. Shen1 , C.S. Park2 , K. Suppipat3 , T.A. Mistretta2 , M. Puppi2 , T. Horton4 , K. Rabin2 , J. Meijerink5 , D. Lacorazza2 . 1 Baylor College of Medicine, Texas Children’s Hospital, Pathology & Immunology, Houston, USA; 2 Baylor College of Medicine, Pathology & Immunology, Houston, USA; 3 Chulalongkorn University, Pediatrics, Bangkok, Thailand; 4 Baylor College of Medicine, Pediatrics, Houston, USA; 5 Erasmus MC, University Medical Center Rotterdam, Pediatrics, Rotterdam, Netherlands T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive blood cancer that affects children and adults, originates from the malignant transformation of lymphoid progenitor cells and is considered to be a highrisk disease due to the poor response to treatment and increased incidence of relapse. Although relapse is the leading cause of death in children with cancer, there is no targeted therapy available for these patients to eliminate chemoresistant leukemic initiating cells (LIC). We have discovered that levels of the Kruppel-like ¨ factor 4 (KLF4), which is known to promote stemness and to reprogram somatic cells into pluripotent stem cells, are significantly low in T-ALL patients, particularly in the ETP and TLX ALL subtypes associated with poor prognosis. In contrast to normal blood cells, we found that lymphoblasts from children with T-ALL exhibit low levels of KLF4 transcripts and hypermethylation of the proximal KLF4 promoter. To study the role of KLF4 and the genetic events governing the transition from a pre-leukemic state to aggressive disease, we used a T-ALL mouse model based on the expression of the gain-of-function NOTCH1-L1601PDP mutant that has weak leukemogenic capacity and is frequently found in patients with T-ALL. Deletion of the Klf4 gene accelerated the onset and worsened disease progression by deregulating the proliferation of leukemic cells and increasing the frequency of LIC identified by limitingdose transplantation and immunophenotypic identification. A combined analysis of global gene expression and genome-wide binding revealed that KLF4 directly repressed the Map2k7 gene encoding the dual specificity mitogen-activated protein kinase 7 (Map2k7) involved in stress MAPKK pathway. Most remarkably, T-ALL cells from both Klf4D/D leukemic mice and pediatric patients displayed elevated levels of total and phosphorylated Map2k7 and subsequent activation of the downstream targets JNK, c-Jun, and ATF2. Pharmacological inhibition of activated JNK induces cytotoxicity in T-ALL cell lines, xenograft model of T-ALL, and cells from relapse T-ALL PDX, suggesting an alternative approach to treat T-ALL. Collectively, these data uncover a novel function for KLF4 by regulating the MAP2K7 pathway in T-ALL that can be targeted to eradicate leukemia-initiating cells in T-ALL patients. No conflict of interest.
Cytotoxics 345 Poster (Board P024) A site-specifically conjugated anti-CD22 antibody bearing an MDR1-resistant maytansine payload yields excellent efficacy and safety in preclinical models D. Rabuka1 , P. Drake1 , A. Carlson1 , J. McFarland1 , R. Barfield1 , S. Banos1 , W. Zmolek1 , Y. Kim1 , B. Huang1 , A. Garofalo1 , R. Kudirka1 . 1 Catalent Biologics, Chemical Biology, Emeryville, USA Background: Hematologically-derived tumors make up ~10% of all newly-diagnosed cancer cases in the U.S. Of these, the non-Hodgkin lymphoma (NHL) designation describes a diverse group of cancers that