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  • 1
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 74, No. 19_Supplement ( 2014-10-01), p. 1976-1976
    Abstract: Multidrug resistance may play a critical role in developing cancer therapeutics for acute leukemia. The expression of the ATP binding cassette (ABC) transporter Pgp/MDR1 (also known as ABCB1) has been reported in AML patients and correlates with poor clinical outcome. Additional transporters like MRP1 and BCRP also appeared to contribute towards this resistance mechanism. We have profiled a panel of AML tumor cell lines and tumor xenografts for both expression and activity of Pgp/MDR1 via FACS and MSD;. Our profiling also includes analysis of the known SNPs associated with these transporters in key models. We have evaluated the sensitivity of the AML models to a series of standard of care therapies, including auristatins, in both in vitro and in vivo studies. These payloads alone or when conjugated to antibodies as antibody drug conjugates (ADCs) are known substrates of the ABC transporters, Using Pgp inhibitors, we could restore the sensitivity of the MDR expressing cells to the cytotoxic drugs and ADCs, which confirmed that the drugs were MDR substrates. These inhibitors could also block the activity of the Pgp pump. We have also observed limited activity in vivo with these ADCs when used in a MDR positive model. Our initial observation indicates that a threshold level of activity of MDR1 may be critical to confer resistance to these standard of care molecules and antibody drug conjugates using similar payloads. Currently, we are investigating the contribution of other efflux pumps in this mechanism of drug resistance MRP1 and BCRP, in similar manner. This can also aid in identifying cytotoxic drugs that are able to bypass the resistance mediated by these efflux pumps. Additional work is underway to characterize patient samples and identify MDR threshold level of activity as a potential predictive biomarker in developing AML therapeutics. Citation Format: Nandini Rudra-Ganguly, Christine Lowe, Mukta Shiwalkar, Claudia I. Guevara, Christopher Kemball, Min Michelle Wu, Cyrus Virata, Alla Verlinsky, Ssucheng J Hsu, Michael Mattie, William Yeh, Peng Yang, Sung-Ju Moon, Ingrid Joseph, David R. Stover, Daniel S. Pereira, Dowdy Jacksosn. MDR expression/ activity may serve as potential biomarker in developing therapeutic drugs for AML therapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1976. doi:10.1158/1538-7445.AM2014-1976
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
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    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2014
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  • 2
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 72, No. 8_Supplement ( 2012-04-15), p. 1314-1314
    Abstract: A major obstacle that has hampered the development and assessment of novel anticancer therapies is the inability of the conventional xenograft models to reliably predict clinical efficacy. This is in part due the fact that the cell lines used for these studies are cultured on plastic for extensive passages and lack the human extracellular matrix component that is critical for cancer-stromal cell interactions. Models are needed which more accurately reflect tumor heterogeneity and interaction with the tumor microenvironment in order to more accurately reflect tumor complexity and predict response to therapies in the clinic. This has led to the development of models by directly engrafting cancer patient-derived tumor tissues into immunodeficient mice with the aim of retaining histopathological features and molecular characteristics of the original tumor. A vital question relating to patient-derived tumor xenografts is whether tumor characteristics are maintained during passaging. We have established a number of proprietary pancreatic cancer patient-derived xenografts. Studies were performed to molecularly characterize the xenograft models and to confirm they retain similarity to the original tumors. Original patient tumors and corresponding serial xenograft passages were examined for growth, histopathological features and protein expression, as well as genomic and tumor biomarker status. Examination of these patient-derived xenograft models demonstrated that tumor morphology is maintained upon passaging. Immunohistochemical and qPCR analysis of targets of interest showed that expression levels are consistent between tumors and xenograft passages. Although slight differences were observed in genomic profiles for some individual models after engraftment in mice, whole genome profiling by microarray and aCGH revealed that individual tumor models retain organ-specific characteristics and that xenografts remain stable throughout passaging. Core sets of significantly expressed genes and genomic aberrations were maintained, with some additional changes observed during passaging. Retention of the characteristics of the original donor tumors within the xenograft models, such as tumor architecture and molecular signatures will afford the use of models which more accurately reflect patient tumor biology. Comprehensive molecular characterization of our models was utilized to investigate differential response to our proprietary drug candidates. Expanded testing in multiple models can potentially provide important pre-clinical translational information to help guide clinical trial design regarding patient subpopulations that may be more likely to respond to therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl): Abstract nr 1314. doi:1538-7445.AM2012-1314
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2012
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  • 3
    In: Neoplasia, Elsevier BV, Vol. 15, No. 10 ( 2013-10), p. 1138-IN17
    Type of Medium: Online Resource
    ISSN: 1476-5586
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2013
    detail.hit.zdb_id: 2008231-9
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  • 4
    In: Cancer Research, American Association for Cancer Research (AACR), Vol. 74, No. 19_Supplement ( 2014-10-01), p. 2650-2650
    Abstract: We have developed AGS67E, an antibody drug conjugate that targets CD37, a tetraspanin highly expressed on malignant B cells, for the potential treatment of non-Hodgkin's lymphoma (NHL), chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML). AGS67E is a fully human anti-CD37 monoclonal IgG2 antibody conjugated to the potent microtubule-disrupting agent, MMAE, via reduced cysteines and the protease cleavable linker, maleimidocaproyl-valine-citrulline-p-aminobenzoyloxycarbonyl. AGS67E exhibits potent in vitro binding, internalization and cytotoxicity on a variety of NHL, CLL and AML models and patient-derived samples, including CD34+CD38- leukemic stem cells. AGS67E also demonstrates potent anti-tumor responses, including complete tumor regressions in a variety of NHL, CLL and AML xenografts, including Rituxan refractory models and patient-derived samples. In general, CD37 was highly expressed across all models and a strong correlation was observed between the in vitro and in vivo efficacy of AGS67E. To confirm binding of AGS67E in a variety of normal and patient-derived NHL, CLL and AML samples, we developed flow cytometry and immunohistochemistry (IHC) assays which have confirmed reported CD37 expression data in NHL & CLL. In normal hematopoietic cells, AGS67E bound strongly to B cells and to a much lesser extent to monocytes, T cells, neutrophils and NK cells. AGS67E also bound with high and similar affinity to cynomolgus monkey B cells and was equally cytotoxic to these and human B cells. In other normal tissues, AGS67E binding was only evident where lymphoid structures were apparent such as in the spleen and lymph node. With respect to CD37 expression in NHL, CLL and AML, AGS67E was found to bind to & gt;80% of NHL and 100% of CLL and AML samples. Taken together, our findings suggest that AGS67E may serve as a potential therapeutic for NHL, CLL and AML. To our knowledge, this body of work is also the first demonstration that CD37 is well expressed and potentially drug-able in AML. Citation Format: Daniel S. Pereira, Claudia Guevara, Alla Verlinsky, Cyrus Virata, J Hsu Ssucheng, Zili An, Chungying Zhang, Nick Dinh, Hector Avina, Lisa Do, Sher Karki, Joseph Abad, Peng Yang, Jimmy Ou, Karen Morrison, Sing-Ju Moon, Faisal Malik, Liqing Jin, Michael Choi, Christina Wu, Banmeet Anand, Scott Cooper, Ingrid Joseph, Xiao-Chi Jia, Kendall Morrison, Pia Challita-Eid, Fernando Donate, Thomas Kipps, John Dick, David Stover. Ags67e, an anti-cd37 monomethyl auristatin e antibody (mmae) drug conjugate as a potential therapeutic for non-hodgkin's lymphoma, chronic lymphocytic leukemia and acute myeloid leukemia. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2650. doi:10.1158/1538-7445.AM2014-2650
    Type of Medium: Online Resource
    ISSN: 0008-5472 , 1538-7445
    RVK:
    RVK:
    Language: English
    Publisher: American Association for Cancer Research (AACR)
    Publication Date: 2014
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    detail.hit.zdb_id: 410466-3
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