# Small molecules targeting RhoA for platelet cold storage in cancer care

> **NIH NIH R01** · CINCINNATI CHILDRENS HOSP MED CTR · 2020 · $635,494

## Abstract

Platelet transfusion in supportive care of cancer patients has seen a significant increase since 1980s,
but a safe, long-term platelet storage method remains missing. Current FDA-mandated practice allows
platelets to be stored at 20 to 24°C after preparation with a limited lifetime up to 5 days due to concerns
about bacterial contamination. Refrigerated storage drastically reduces platelet life-span because it
causes glycoprotein-Ib (GPIb) receptors to cluster on specific microdomains of the platelet membrane.
Recognition of specific de-glycated/de-syalylated residues on clustered glycoproteins by von Willebrand
factor, macrophage β2 integrins and hepatocyte Ashwell-Morell receptors results in platelet
phagocytosis by the host and removal from circulation. Thus, prevention of glycoprotein clustering
represents a useful way for chemical intervention. Platelet glycoproteins are intimately associated with
intracellular cytoskeleton and their glycosylation depends on the location and activity of specific
glycosyl-transferases. Their clustering depends on the formation of lipid raft in the platelet membrane
which in turn depends on the dynamics of the highly regulated processes of cytoskeletal
rearrangements. RhoA is the founding member of the Rho GTPase family that are central regulators of
cytoskeletal dynamics, and has been shown to control lipid raft formation and composition. Therefore,
changes in RhoA activity may influence platelet membrane lipid raft assembly and glycoprotein
composition. Our preliminary studies by genetic and pharmacological means show that cold receptor
upregulates RhoA activity, which in turn induces platelet activation. We have discovered a lead RhoA
inhibitor, Rhosin/G04, that is specific to RhoA activation and is able to mimic RhoA knockout to prevent
clathrin-independent internalization of lipid raft enriched in glycosyl transferase and cold-induced GPIb
clustering. We hypothesize that RhoA inhibition can prevent platelet cold-induced GPIb clustering and
consequent clearance by host upon transfusion, and that development of a reversible RhoA inhibitor
can be translated to a new regimen of platelet cold storage. In this proposal, we will determine the
mechanism of action by the lead RhoA inhibitor, Rhosin/G04, and demonstrate the therapeutic benefits
of Rhosin/G04 and analogues for efficacious refrigerated long-term platelet storage in mouse models
and non-human primates. The combination of drug discovery, medicinal chemistry and structural
biology, cell biology, and platelet transfusion expertise as demonstrated by the co-PIs led to this highly
innovative, outside-the-box method for intervention in platelet storage technology. Small molecule
targeting of RhoA GTPase through the interference of protein-protein interaction is a revolutionary
approach allowing for reversible inhibition of RhoA and help preserve cold stored platelet function. Our
innovation through the preclinical drug discovery effort will benefit cancer p...

## Key facts

- **NIH application ID:** 9900068
- **Project number:** 5R01HL147536-02
- **Recipient organization:** CINCINNATI CHILDRENS HOSP MED CTR
- **Principal Investigator:** Jose A. Cancelas
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $635,494
- **Award type:** 5
- **Project period:** 2019-04-01 → 2023-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9900068

## Citation

> US National Institutes of Health, RePORTER application 9900068, Small molecules targeting RhoA for platelet cold storage in cancer care (5R01HL147536-02). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/9900068. Licensed CC0.

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