(1-4)-S-thiodisaccharides with 1-4-thio bridge are possesing anti-cancer properties. They induced oxidative stress and apoptosis in cancer cells at the micromolar level [1,2]. However, the mechanism of their action is not clearly established. Many reports showed that induction of reactive oxygen species (ROS) is directly or indirectly provoked by ER stress. In this condition unfolded protein response (UPR) is activated. ER stress is sensed by three transmembrane proteins: PERK, ATF6 and IRE1 and activation this three signaling pathways is characteristic for UPR. Cell death is induced if the cell cannot deal with with ER stress. We investigated the mechanism of action of two (1-4)-S-thiodisacharides with sulfur bridge denoted respectively as FCP6 and FCP8 [Fig1] on glioma cells (U87 cell line). In order to determine the mechanism of activity we performed a series of tests including expression analysis at the mRNA and protein level. The methods are based on analysis of UPR-induced transcripts by qPCR (the following markers will be analyzed: EDEM, Grp78, ERP72, CHOP, ATF4, HERP, P58ipk and also XBP1 cleavage), and ELISA/ Western blot-based analysis of UPR-induced proteins or their modifications (CHOP, eIF2α, Phospho- eIF2α, GRP78, XBP1s, ATF6). These methods are able to monitor activation of all three sub-pathways of the UPR. We also analyzed cytosolic Ca2+ influx using Fluoro-4-AM which generates green fluorescence upon interaction with Ca2+. Both (1-4)-S-thiodisaccharides induced ER stress and induction of apoptosis of glioma cell. We postulated that the anticancer mechanism of FCPs is a consequence of oxidative stress, endoplasmic reticulum stress, inhibition of protein synthesis and inhibition of thioredoxin reductase activity (as previously reported 1,2). The FCP6 was the most effective with low micromolar concentrations [IC50= 65,2 µM on U87 cell line].

(1-4)-S-thiodisacharides induction of ER stress as possible mechanism of glioblastoma cells death

2019 Spring National Meeting

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