P01.02 Selective induction of cell death in Jurkat cells with recombinant fungal lectin CNL

BackgroundDue to their capacity to specifically recognize subtle alterations in glycoproteins on the cell surface lectins are increasingly being used in diagnostic (for identification of malignant or premalignant cells) and therapeutic purposes (for targeted drug delivery).Materials and MethodsWe have previously isolated and biochemically characterized a fungal lectin Clitocybe nebularis lectin (CNL) . We have synthetized recombinant form of CNL and tested its effects on different human cell lines and primary cells using various biochemical and molecular biological assays.ResultsCNL is a GalNAcβ1–4GlcNAc-binding lectin that shows an antiproliferative effect solely on the leukemic Jurkat T cells. Furthermore, recombinant CNL treated Jurkat T cells exhibited archetypal features of early apoptosis, homotypic agglutination but lacked the activation of initiating and executing caspases since none of the features of CNL-induced cell death was effectively blocked with the pan-caspase inhibitor or different peptidase inhibitors. In addition, CNL binding induced Jurkat cells to release the endogenous damage-associated molecular pattern molecule high-mobility group box 1 (HMGB1), which is typically associated with necroptosis. We have identified CD45 and CD43 cell surface glycoproteins as main binding targets on the cell surface of Jurkat cells. However, the blockade of CD45 phosphatase activity failed to block either CNL-induced homotypic agglutination or cell death. Remarkably, a plant lectin, Wisteria floribunda agglutinin (WFA), which shows similar specificity in ligand binding, showed less selective cytotoxicity and induced cell death in Jurkat cells, Tall-104 acute lymphoblastic leukemia, and Hut-87 cutaneous T-cell lymphoma cell lines with similar uncharacteristic features.ConclusionsSelective targeting of Jurkat T cells may reflect potential applicability of CNL in novel strategies for treating and/or detecting acute T cell leukemia. [Perišić Nanut, M, Žurga, S, Konjar, Š, Prunk, M, Kos, J, Sabotič, J. The fungal Clitocybe nebularis lectin binds distinct cell surface glycoprotein receptors to induce cell death selectively in Jurkat cells. FASEB J. 2022; 36: e22215. doi:10.1096/fj.202101056RR]Disclosure Information M.M. Perisic Nanut: None. S. Žurga: None. Š. Konjar: None. M. Prunk: None. J. Kos: None. J. Sabotič: None.