Doxorubicin directly binds to platelet CLEC-2 with an affinity of 4.2 nM, leading to ADAM17-mediated shedding of GPIbα and reducing its surface expression by approximately 50% in human platelets.
Does doxorubicin induce GPIbα shedding via CLEC-2 activation in platelets?
Doxorubicin binds to platelet CLEC-2, leading to ADAM17-mediated GPIbα shedding, providing a mechanistic explanation for doxorubicin-induced platelet activation and thrombocytopenia.
Absolute Event Rate: 50% vs 100%
Doxorubicin (Dox) is a potent first-line chemotherapeutic and widely administered against different types of cancer, but is associated with a myriad of side effects, including cancer/chemotherapy-associated thrombosis and drug-induced thrombocytopenia (DIT).Although we and others have reported Dox-induced platelet activation, the binding partner of Dox on platelets has not been previously explored.Here, we found human and mouse platelet aggregation triggered via C-Type Lectin-like Receptor-2 (CLEC-2) was obstructed by Dox, but aggregation induced by classical agonists like ADP, collagen/collagen-related peptide, or thrombin receptoractivating peptide 6 (TRAP6), was unaffected.By Isothermal Titration Calorimetry, we detected a high binding affinity between Dox and recombinant CLEC-2 at 4.2 2.4 nM.Interestingly, we found significant GPIb shedding from human and mouse platelet surfaces following Dox treatment.Consistently, GPIb shedding was recapitulated following anti-CLEC-2 monoclonal antibody treatment.Using Piceatannol to selectively inhibit CLEC-2 intracellular signaling or the pan-Matrix Metalloproteinases (MMP) inhibitor GM6001 rescued GPIb from both Dox and CLEC-2 mAb-induced shedding.Using GI254023X or GW280264X to specifically inhibit ADAM10 or ADAMs10/17, respectively, revealed inhibition of ADAM10/17, but not ADAM10 exclusively, prohibited GPIb shedding.Collectively, this implicates the classical sheddase of GPIb, ADAM17.Thus, we pinpointed CLEC-2 as a binding partner for Dox on platelets and a novel pathway of ADAM17-mediated GPIb shedding via CLEC-2.These data not only provide insights into a mechanism of Dox-induced platelet activation, thrombosis, and DIT, but also reveal putative precision therapeutic approaches for Dox-treated patients and nominate CLEC-2 inhibition as a means to regulate thrombotic disease and/or bleeding disorders.
Rousseau et al. (2026) studied Healthy volunteers and murine models (preclinical). Doxorubicin vs. Vehicle control was evaluated on Surface GPIbα expression on human platelets. Doxorubicin directly binds to platelet CLEC-2 with an affinity of 4.2 nM, leading to ADAM17-mediated shedding of GPIbα and reducing its surface expression by approximately 50% in human platelets.