Abstract 4713: Chlorpromazine affects glioblastoma bioenergetics by interfering with pyruvate kinase M2: A route for drug repurposing in glioblastoma
Authors: Abbruzzese Claudia , Matteoni Silvia , Matarrese Paola , Signore Michele , Ascione Barbara , Iessi Elisabetta , Gurtner Aymone , Sacconi Andrea , Pace Andrea , Villani Veronica , Polo Andrea , Costantini Susan , Budillon Alfredo , Ciliberto Gennaro , Paggi Marco G. 
Published: March 2024

Abstract
Glioblastoma, the most common and deadly brain tumor, remains a critical unmet medical need due to the limited effectiveness of current treatments. Drug repurposing has recently emerged as a promising strategy to improve glioblastoma outcomes. Antipsychotic drugs, with their established safety profile and potential to disrupt tumor-neuron interactions, have drawn particular attention. Among these, chlorpromazine, a well-tolerated medication included in the 2021 WHO Model List of Essential Medicines, holds promise due to its therapeutic effects in psychiatric disorders stemming from its non-specific interference with various CNS neurotransmitter receptors. Our recent studies have demonstrated chlorpromazine's ability to inhibit several molecular and cellular processes in glioblastoma cells, suggesting its potential as a novel treatment option for this challenging disease.To elucidate chlorpromazine's mechanism of action as a potential anticancer drug, we employed two proteomics approaches: Reverse-Phase Protein microArrays to evaluate its impact on signal transduction pathways and Activity-Based Protein Profiling followed by mass spectrometry to identify novel molecular targets.Our data revealed that chlorpromazine significantly modulates major signal transduction pathways and implicates pyruvate kinase (PK) M2 as a drug target. PKM2, a PK variant characteristic of many cancers, plays a crucial role in orchestrating metabolic alterations, exemplified by the Warburg effect – the high glucose consumption and lactate production by cancer cells even under oxygen-rich conditions. PKM2 functions as a tetramer in the glycolytic pathway, while its dimeric form acquires nuclear localization, protein kinase activity, and interacts with various transcription factors, contributing to its pro-tumorigenic activity.Consistent with its ability to target PKM2, chlorpromazine promoted PKM2 tetramerization in glioblastoma cells, leading to significant alterations in glioblastoma energy metabolism. Notably, RPE-1 non-cancer neuroepithelial cells showed a reduced response to the drug. Additionally,
silencing PKM2 diminished the effects of chlorpromazine. 3D modeling revealed that chlorpromazine interacts with the PKM2 tetramer at the same site involved in binding other small-molecule activators that stabilize the PKM2 tetramer.These findings suggest that chlorpromazine counteracts the Warburg effect and, consequently, malignancy in glioblastoma cells, while sparing non-cancerous RPE-1 cells. This preclinical evidence supports the rationale behind our recently completed multicenter Phase II clinical trial investigating the role of chlorpromazine in glioblastoma treatment. The study is registered as EudraCT #2019-001988-75 and ClinicalTrials.gov Identifier #NCT0422444.
Citation Format: Claudia Abbruzzese, Silvia Matteoni, Paola Matarrese, Michele Signore, Barbara Ascione, Elisabetta Iessi, Aymone Gurtner, Andrea Sacconi, Andrea Pace, Veronica Villani, Andrea Polo, Susan Costantini, Alfredo Budillon, Gennaro Ciliberto, Marco G. Paggi. Chlorpromazine affects glioblastoma bioenergetics by interfering with pyruvate kinase M2: A route for drug repurposing in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4713.