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European Pharmaceutical Students’ Association
TARGETING AUTOPHAGY COMPLEMENTS THE ACTION OF IBRUTINIB AND VENETOCLAX IN CHRONIC LYMPHOCYTIC LEUKEMIA CELLS Authors: Alma Tana Jakoš Djordjevič Scientific coordinator: prof. dr. Irena Mlinarič-Raščan, Damjan Avsec Institution: University of Ljubljana, Faculty of Pharmacy, Chair of Clinical Biochemistry
INTRODUCTION: Chronic lymphocytic leukemia (CLL) is the most common leukemia in the Western world. In the recent years, BTK inhibitor ibrutinib, PI3K inhibitor idelalisib, and Bcl-2 antagonist venetoclax revolutionized the treatment of CLL. However, these therapies present with several drawbacks, such as severe adverse events and emergence of resistance. Therefore, the demand for novel targets is high. One of such targets is autophagy, a protective and degradative cell process that plays an important but still fairly undefined role in CLL. AIM: To elucidate the antileukemic potential of mechanism of cell death. The mean EC50 values of MRT68921 in patient-derived CLL targeting autophagy in CLL. cells (n = 13) were 3.6 μM and 2.9 μM after MATERIAL AND METHODS: Autophagy 24 and 48 hour treatment, respectively, reporter cell line THP-1 Difluo hLC3 and demonstrating that MRT68921 acts in a imaging flow cytometry were used to monitor concentration and time-dependent manner (p autophagic flux. Autophagy was blocked using = 0.0036). Moreover, compared to peripheral ULK1/2 inhibitor MRT68921. Cytotoxic and blood mononuclear cells MRT68921 was synergistic effects of MRT68921 and targeted more cytotoxic to CLL cells (p = 0.0013), therapy in primary CLL cells (the study was indicating it acts selectively cytotoxic towards approved by Slovenian National Medical malignant B cells. Ethics Committee; 0120-136/2019/4) were evaluated using PrestoBlue assay. To identify CONCLUSION: In the present study we the mechanisms of synergistic effects, PI demonstrated that autophagy inhibition uptake and cell cycle assay were performed with ULK1/2 inhibitor MRT68921 acts selectively cytotoxic towards malignant B using flow cytometry. cells and augments the action of ibrutinib RESULTS: Using autophagy reporter cells, and venetoclax. Thus, we recognized we showed that ibrutinib and venetoclax but autophagy as an important target and not idelalisib induce autophagy. Blocking the inhibition of autophagy as a promising induction of autophagy with ULK1/2 inhibitor new approach for the treatment of CLL MRT68921 augmented the cytotoxicity of ibrutinib and venetoclax in CLL cell line MEC-1 and primary CLL cells. Furthermore, MRT68921 alone was able to cause cell cycle arrest at G2/M phase, but in combination with ibrutinib and venetoclax, it acted synergistically cytotoxic through a caspase-dependent mechanism, indicating that apoptosis is the
