Allosteric Antagonist Modulation of TRPV2 by Piperlongumine Impairs Glioblastoma Progression

Abstract

The use of computational tools to identify biological targets of natural products with anticancer properties and unknown modes of action is gaining momentum. We employed self-organizing maps to deconvolute the phenotypic effects of piperlongumine (PL) and establish a link to modulation of the human transient receptor potential vanilloid 2 (hTRPV2) channel. The structure of the PL-bound full-length rat TRPV2 channel was determined by cryo-EM. PL binds to a transient allosteric pocket responsible for a new mode of anticancer activity against glioblastoma (GBM) in which hTRPV2 is overexpressed. Calcium imaging experiments revealed the importance of Arg539 and Thr522 residues on the antagonistic effect of PL and calcium influx modulation of the TRPV2 channel. Downregulation of hTRPV2 reduces sensitivity to PL and decreases ROS production. Analysis of GBM patient samples associates hTRPV2 overexpression with tumor grade, disease progression, and poor prognosis. Extensive tumor abrogation and long term survival was achieved in two murine models of orthotopic GBM by formulating PL in an implantable scaffold/hydrogel for sustained local therapy. Furthermore, in primary tumor samples derived from GBM patients, we observed a selective reduction of malignant cells in response to PL ex vivo . Our results establish a broadly applicable strategy, leveraging data-motivated research hypotheses for the discovery of novel means tackling cancer.

Structural mechanisms of TRPV6 inhibition by ruthenium red and econazole

“…Of other inhibitory binding sites in TRP channels, the location of the econazole-binding site in TRPV6 (Fig. 4 ) has the highest similarity with the location of a piperlongumine-binding site in TRPV2 65 . Compared with the econazole-binding site in TRPV6, the piperlongumine-binding site in TRPV2 is wedged deeper between S4 and S5 and makes contact with S6.…”

Uncovering Spatiotemporal Heterogeneity of High-Grade Gliomas: From Disease Biology to Therapeutic Implications

“…However, it is yet unclear how clinical therapeutics can be altered to target this intra and intertumoral heterogeneity. We must consider therapies that address multiple resistance pathways, including immune-based therapies that may target multiple tumor antigens (19,(161)(162)(163), or therapies targeting common metabolic and physiological pathways, which may improve chances of success (164,165). Furthermore, greater effort in developing preclinical models and clinical studies to understand spatial heterogeneity, tumor recurrence, and evolutionary trajectories in GBM are vital (Figure 2).…”

Applications of Cryo-EM in small molecule and biologics drug design

“…Residues forming the ion pore are indicated. Lower right inset , Piperlongumine binding site of TRPV2 (PDB 6WKN [ 53 ]), with TRPV2 cartoon colored by subunit and piperlongumine in stick representation. Key interacting residues are shown as sticks.…”

“…Electrophysiological studies revealed the channel to be active in the presence of CBD when reconstituted in liposomes, but to open occasionally for extended periods even in the apo form, suggesting membrane lipids may modulate its activity. A follow-up structure of TRPV2 was reported this year in the presence of piperlongumine, a naturally occurring alkaloid with selective anti-cancer properties [ 53 ]. Notably, the activity of piperlongumine was predicted computationally using SPIDER, a tool used to identify associations between small molecules and their protein targets, and it was subsequently validated in vivo as a TRPV2 antagonist.…”