A Novel Approach for Glioblastoma Treatment by Combining Apoptosis Inducers (TMZ, MTX, and Cytarabine) with E.V.A. (Eltanexor, Venetoclax, and A1210477) Inhibiting XPO1, Bcl-2, and Mcl-1.

in Cells by Kai Zhao, Madita Braun, Leonie Meyer, Katharina Otte, Hartmann Raifer, Frederik Helmprobst, Vincent Möschl, Axel Pagenstecher, Hans Urban, Michael W Ronellenfitsch, Joachim P Steinbach, Jelena Pesek, Bernhard Watzer, Wolfgang A Nockher, R Verena Taudte, Andreas Neubauer, Christopher Nimsky, Jörg W Bartsch, Tillmann Rusch

TLDR

  • The study found that a combination of certain drugs can kill cancer cells in the brain. The drugs work by blocking proteins that help the cancer cells survive. The study suggests that this combination of drugs is safe and effective and should be tested in people to see if it works.

Abstract

Adjuvant treatment for Glioblastoma Grade 4 with Temozolomide (TMZ) inevitably fails due to therapeutic resistance, necessitating new approaches. Apoptosis induction in GB cells is inefficient, due to an excess of anti-apoptotic XPO1/Bcl-2-family proteins. We assessed TMZ, Methotrexate (MTX), and Cytarabine (Ara-C) (apoptosis inducers) combined with XPO1/Bcl-2/Mcl-1-inhibitors (apoptosis rescue) in GB cell lines and primary GB stem-like cells (GSCs). Using CellTiter-Gloand Caspase-3 activity assays, we generated dose-response curves and analyzed the gene and protein regulation of anti-apoptotic proteins via PCR and Western blots. Optimal drug combinations were examined for their impact on the cell cycle and apoptosis induction via FACS analysis, paralleled by the assessment of potential toxicity in healthy mouse brain slices. Ara-C and MTX proved to be 150- to 10,000-fold more potent in inducing apoptosis than TMZ. In response to inhibitors Eltanexor (XPO1; E), Venetoclax (Bcl-2; V), and A1210477 (Mcl-1; A), genes encoding for the corresponding proteins were upregulated in a compensatory manner. TMZ, MTX, and Ara-C combined with E, V, and A evidenced highly lethal effects when combined. As no significant cell death induction in mouse brain slices was observed, we conclude that this drug combination is effective in vitro and expected to have low side effects in vivo.

Overview

  • The study aims to investigate the effectiveness of combining apoptosis inducers with XPO1/Bcl-2/Mcl-1-inhibitors in inducing apoptosis in Glioblastoma Grade 4 (GB) cells and primary GB stem-like cells (GSCs).
  • The study uses CellTiter-Glo and Caspase-3 activity assays to generate dose-response curves and analyze the gene and protein regulation of anti-apoptotic proteins via PCR and Western blots. Optimal drug combinations are examined for their impact on the cell cycle and apoptosis induction via FACS analysis, paralleled by the assessment of potential toxicity in healthy mouse brain slices.

Comparative Analysis & Findings

  • Ara-C and MTX proved to be 150- to 10,000-fold more potent in inducing apoptosis than TMZ. In response to inhibitors Eltanexor (XPO1; E), Venetoclax (Bcl-2; V), and A1210477 (Mcl-1; A), genes encoding for the corresponding proteins were upregulated in a compensatory manner. TMZ, MTX, and Ara-C combined with E, V, and A evidenced highly lethal effects when combined.

Implications and Future Directions

  • The study's findings suggest that combining apoptosis inducers with XPO1/Bcl-2/Mcl-1-inhibitors is an effective approach to inducing apoptosis in GB cells and GSCs. Future research should focus on developing clinical trials to test the efficacy and safety of this drug combination in vivo.
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