Combinatory Treatment of Canavanine and Arginine Deprivation Efficiently Targets Human Glioblastoma Cells via Pleiotropic Mechanisms

Abstract

Glioblastomas are the most frequent and aggressive form of primary brain tumors with no efficient cure. However, they often exhibit specific metabolic shifts that include deficiency in the biosynthesis of and dependence on certain exogenous amino acids. Here, we evaluated, in vitro, a novel combinatory antiglioblastoma approach based on arginine deprivation and canavanine, an arginine analogue of plant origin, using two human glioblastoma cell models, U251MG and U87MG. The combinatory treatment profoundly affected cell viability, morphology, motility and adhesion, destabilizing the cytoskeleton and mitochondrial network, and induced apoptotic cell death. Importantly, the effects were selective toward glioblastoma cells, as they were not pronounced for primary rat glial cells. At the molecular level, canavanine inhibited prosurvival kinases such as FAK, Akt and AMPK. Its effects on protein synthesis and stress response pathways were more complex and dependent on exposure time. We directly observed canavanine incorporation into nascent proteins by using quantitative proteomics. Although canavanine in the absence of arginine readily incorporated into polypeptides, no motif preference for such incorporation was observed. Our findings provide a strong rationale for further developing the proposed modality based on canavanine and arginine deprivation as a potential antiglioblastoma metabolic therapy independent of the blood–brain barrier.

Polyphenolic Compounds of Crataegus Berry, Leaf, and Flower Extracts Affect Viability and Invasive Potential of Human Glioblastoma Cells

“…It was shown, among others, that polyphenolic compounds apart from the mentioned mutual combinations could also be combined with other natural compounds such as sugar derivatives, glycosides, peptides, and amino acids [ 51 ]. These studies seemed to be highly relevant in the context of our recent report showing that plant-derived amino acid canavanine (an arginine analog) had a strong cytotoxic effect on two human glioblastoma cell lines, U87MG and U251MG [ 56 ].…”

Synthetic lethality between toxic amino acids, retrograde target genes and chaperones in Saccharomyces cerevisiae

“…The copyright holder for this preprint this version posted February 18, 2022. ; https://doi.org/10.1101/2022.02. 18.481112 doi: bioRxiv preprint 4 the incorporation of canavanine into proteins can be detected at a media concentration of about 10 µg/ml [7]. We have shown that respiration-deficient yeasts (petites) produce less arginine than the respiratory WT and that canavanine induces mistargeting of arginine biosynthesis enzymes.…”

“…In this way, canavanine has antimicrobial properties and offers protection for the seeds containing it [4]. For years canavanine has been considered as a possible anticancer agent [5, 6], and recently has been shown to have potential as an anti-glioblastoma metabolic therapy when combined with arginine deprivation [7]. In fact, arginine deprivation alone has been shown to induce endoplasmic reticulum stress in solid human cancer cells [8] and arginine deprivation therapy (ADT) is currently being explored as a new metabolic targeting approach with high therapeutic potential for various solid cancers [9, 10].…”

Molecular and Cellular Mechanisms of Glioblastoma

“…Among the 14 articles, different important issues related to glioblastomas are studied, such as resistance to treatment [7][8][9][10], cancer stem cells [7,8,11], metabolism [8,12], epithelial-to-mesenchymal transition (EMT) [11,13] and ROS [9,12,14].…”

“…Karatsai et al [12] treated arginine-deprived glioblastoma cells with the arginine analogue canavanine, and detected increased apoptotic cell death only in tumor cells, opening the door to metabolic therapy against glioblastoma.…”