Browsing by Subject "ex vivo"

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  • Pietarinen, Paavo O.; Eide, Christopher A.; Ayuda-Duran, Pilar; Potdar, Swapnil; Kuusanmaki, Heikki; Andersson, Emma I.; Mpindi, John P.; Pemovska, Tea; Kontro, Mika; Heckman, Caroline A.; Kallioniemi, Olli; Wennerberg, Krister; Hjorth-Hansen, Henrik; Druker, Brian J.; Enserink, Jorrit M.; Tyner, Jeffrey W.; Mustjoki, Satu; Porkka, Kimmo (2017)
    Tyrosine kinase inhibitors (TKI) are the mainstay treatment of BCR-ABL1-positive leukemia and virtually all patients with chronic myeloid leukemia in chronic phase (CP CML) respond to TKI therapy. However, there is limited information on the cellular mechanisms of response and particularly on the effect of cell differentiation state to TKI sensitivity in vivo and ex vivo/in vitro. We used multiple, independent high-throughput drug sensitivity and resistance testing platforms that collectively evaluated 295 oncology compounds to characterize ex vivo drug response profiles of primary cells freshly collected from newly-diagnosed patients with BCR-ABL1positive leukemia (n = 40) and healthy controls (n = 12). In contrast to the highly TKI-sensitive cells from blast phase CML and Philadelphia chromosome-positive acute lymphoblastic leukemia, primary CP CML cells were insensitive to TKI therapy ex vivo. Despite maintaining potent BCR-ABL1 inhibitory activity, ex vivo viability of cells was unaffected by TKIs. These findings were validated in two independent patient cohorts and analysis platforms. All CP CML patients under study responded to TKI therapy in vivo. When CP CML cells were sorted based on CD34 expression, the CD34-positive progenitor cells showed good sensitivity to TKIs, whereas the more mature CD34-negative cells were markedly less sensitive. Thus in CP CML, TKIs predominantly target the progenitor cell population while the differentiated leukemic cells (mostly cells from granulocytic series) are insensitive to BCR-ABL1 inhibition. These findings have implications for drug discovery in CP CML and indicate a fundamental biological difference between CP CML and advanced forms of BCR-ABL1-positive leukemia.
  • Hemmila, Samu; Ruponen, Marika; Toropainen, Elisa; Tengvall-Unadike, Unni; Urtti, Arto; Kallio, Pasi (2020)
    This paper presents a novel microflow-based concept for studying the permeability of in vitro cell models or ex vivo tissues. Using the proposed concept, we demonstrate how to maintain physiologically relevant test conditions and produce highly reproducible permeability values for a range (31) of drug compounds. The apparent permeability coefficients (P-app) showed excellent correlation (0.89) with the values from experiments performed with a conventional Ussing chamber. Additionally, the microflow-based concept produces notably more concentrated samples than the conventional Ussing chamber-based approach, despite the fact that more than 10 times smaller quantities of test compounds and biological membranes are needed in the microflow-based concept.
  • Ranta, Amanda Katrianna (Helsingin yliopisto, 2020)
    Ex vivo drug sensitivity testing is used widely in studies aiming at personalizing medicine for acute myeloid leukemia (AML) patients. However, different conditions, such as cytokines used in media and cryopreservation of cells, as well as varying readout methods can affect primary cell viability, cell composition and sensitivity results. Such affects have been previously studied in some AML treatments, however, not with flow cytometry or with venetoclax. In this thesis, we studied the responses of AML patients to venetoclax using ex vivo drug sensitivity testing with various settings. We first tested three media and two sensitivity readout methods on 29 fresh primary AML samples to determine the optimal media and method for determining ex vivo drug sensitivity. We then tested these same variables on 16 cryopreserved samples and compared these results to their fresh counterparts. Finally, we applied our platform to clinical use and tested its capability to predict in vivo responses to venetoclax in ten AML patients. Our platform was able to predict venetoclax responses in nine out of ten patients using condition media coupled with a flow cytometry-based method, determined as optimal in the first phase. Sensitivity results as well as cell composition obtained after cryopreservation differed from their fresh counterparts and, therefore, we conclude that cryopreserved samples should not be used in guiding treatment ex vivo. Our results give valuable information about sources of error associated with ex vivo drug sensitivity testing. Consideration of these results when designing preclinical studies will enhance their reliability and relevance. Ex vivo testing could be in the future implemented into clinical practice in guiding treatment, saving society and patients from costs and unnecessary adverse effects.