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

Abstract

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.

<p>Combined Delivery of Temozolomide and siPLK1 Using Targeted Nanoparticles to Enhance Temozolomide Sensitivity in Glioma</p>

“…Although it is used widely to treat patients with glioma, its effectiveness in treatment is not very high because of TMZ resistant glioma. 48,49 PLK1 is a serine/threonine protein kinase that is an early trigger for G2/M conversion in the cell cycle. 50 Inhibition of PLK1 expression can arrest the cell cycle in the G2/M phase, thereby increasing the effectiveness of chemotherapy drugs.…”

Mechanisms of Cell Cycle Arrest and Apoptosis in Glioblastoma

“…Piperidinones, such as AMG232, are further MDM2-p53 interaction inhibitors, which are tested in a phase I clinical trial in primary and recurrent GBM (NCT03107780) (https://clinicaltrials.gov/ct2/show/NCT03107780, accessed on 30 December 2021). Alternative ways of restoring p53 functions are direct blocking of MDM2 expression via siRNA [82] or restoration of p53 expression via a p53 activator, such as RITA [83]. Similarly, targeting the Rb pathway and CDKs or cyclins drives GBM cells to cell cycle arrest in GBM models [84,85].…”

MDM2/X Inhibitors as Radiosensitizers for Glioblastoma Targeted Therapy

“…In vivo in GB, RITA showed synergistic effects when combined with TMZ and an inhibition of cell growth and stemness, as well as apoptosis induction. Interestingly, RITA acted independently of the p53 status ( 156 ). Protein expression studies showed that RITA suppressed cell proliferation by targeting the p53 associated protein ASK1 ( 156 ).…”

“…Interestingly, RITA acted independently of the p53 status ( 156 ). Protein expression studies showed that RITA suppressed cell proliferation by targeting the p53 associated protein ASK1 ( 156 ). Johansson et al tested its efficacy in combination with the proteasome inhibitor bortezomib and despite showing specific single-agent activity in p53 mut cells, it did not strengthen bortezomib activity ( 154 ).…”