Study on Therapeutic Action and Mechanism of TMZ Combined with RITA Against Glioblastoma

Background/aims: Glioblastoma multiforme (GBM) is a malignant and aggressive central nervous system (CNS) tumor with high mortality and low survival rate. Effective treatment of GMB is a challenge worldwide. Temozolomide (TMZ) is a drug used to treat GBM, while the survival period of GBM patients with positive treatment remains less than 15 months. Reactivating p53 and Inducing Tumor Apoptosis (RITA) is a novel potential anti-cancer small molecular drug. Thus, it is essential to discover novel targets or develop effective drugs combination strategy to treat GBM.

Methods: The U87 cells and U251 cells (p53 mutated) were treated with DMSO and 1, 5,10, 20 μM RITA, TMZ, RITA+TMA or PFT-α. The cell proliferation was measured using the MTS cell proliferation assay. The cell apoptosis was analyzed by Annexin V-FITC/PI Apoptosis Detection Kit. The key protein expression level was evaluated by WB. Molecular docking and molecular dynamics (MD) simulation methods were applied to simulate the interaction between RITA and ASK1.

Results: Herein, we found that combination RITA and TMZ effectively inhibited the proliferation of U87 cells and promoted the apoptosis of U87 cells. Then the mechanism of RITA and TMZ treating GBM were further studied by detecting the expression of the proteins associating with p53 pathway, such as ASK1, Bax, and so on. RITA bound to the amino acids residues in the activation domain of the ASK1, then induced the conformation change of ASK1 receptor, activated ASK1 and caused a series of signal transduction, further resulted in the physiological effects.

Conclusion: Taken together, the RITA suppressed the cell proliferation in glioblastoma via targeting ASK1.