Novel anti-cancer compound – inibitor of TrxR distress GSH system in glioma cells

Abstract

Glioblastoma is the most frequent malignant brain tumor, with limited therapy options due to aggressive invasiveness and resistance to therapy . Elevated expression of redox system components, thioredoxin (Trx) and thioredoxin reductase (TrxR), is a common feature of cancer cells and correlates with cancer progression and poor prognosis. Therefore, Trx and TrxR are attractive targets for chemotherapy development. Inhibition of Trx system may also affect another important redox system – the glutathione (GSH) system. Here, we investigated weather GSH system can compensate Trx system inhibition by novel TrxR1 inhibitor (DVD-444) in human and rat drug resistant glioma cell lines and their sensitive counterparts. RT-qPCR analysis showed that DVD-444 decreased GSH peroxidase 1 (GPX1) and 4 (GPX4) mRNA expression in all glioma cell lines. Decrease in GPX expression indicates suppression of another antioxidant defense system, besides Trx system, leaving cells vulnerable to oxidative stress. Tested compound caused an increase in expression of GSH reductase (GR) and GSH-S transferase π (GSTπ). The observed increase in GR could be the consequence of oxidative stress imposed by treatment with TrxR1inhibitor, while elevated GSTπ implies that GSTπ is highly involved in detoxification of the applied compound. Furthermore, colorimetric GSH assay showed that DVD-444 increased GSH cell content in glioma cell lines. AV/PI staining following treatment with TrxR1 inhibitor demonstrated significant level of cell death in rat glioma cell lines. Based on CFSE staining DVD-444 showed antiproliferative effect in human glioma cells. In conclusion, TrxR1 inhibitor caused changes in components of GSH system. However, the changes in GSH system did not prevent inhibition of cell proliferation and cell death evasion after TrxR1 inhibition, making DVD-444 perspective candidate for glioblastoma treatment strategy