Webinar Featuring Joyce Bischoff
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Webinar Featuring Joyce Bischoff
Thursday, December 7, 2023 (1:00 PM - 2:00 PM) (EST)
Description
Join us for a webinar with Joyce Bischoff, Ph.D., Professor of Surgery at Harvard Medical School/Boston Children's Hospital. She will present her talk entitled: “Cellular Drivers and Drug Mechanisms in Infantile Hemangioma."
Abstract: Infantile hemangioma (IH) is a benign vascular tumor that occurs in 5% of infants; in ~10% of cases, the vascular overgrowth causes severe problems for the infant. Propranolol was discovered serendipitously to be effective for IH; despite its success, there is significant need for improved therapies because of side effects caused by its non-selective β-blocker activity. We previously showed the R+ enantiomer of propranolol, which lacks β-blocker activity, inhibits hemangioma stem cell (HemSC) vessel formation in vivo and HemSC to endothelial differentiation in vitro via disruption of the transcription factor SOX18 - indicating a β-adrenergic independent mechanism for propranolol therapy in IH (Seebauer et al., JCI 2022).
In new experiments, we discovered R+ propranolol suppresses the mevalonate pathway in HemSC undergoing endothelial differentiation. The mevalonate pathway, central to cholesterol biosynthesis, is controlled by the rate-limiting enzyme 3 hydroxy-3-methylglutaryl-coenzyme A reductase. Confirming its functional requirement, simvastatin and atorvastatin inhibited HemSC vessel formation in vivo and HemSC endothelial differentiation in vitro. R+ propranolol inhibited maturation of SREBP-2, the master transcription factor for the mevalonate pathway genes and further, R+ propranolol reduced endogenous cholesterol levels in human ECs. Sm4, a SOX18 inhibitor, showed similar results in these experiments.
We propose an entirely novel SOX18-mevalonate pathway axis as a central regulatory process in IH-vascular overgrowth. This presents potentially new clinical research directions in which R+ propranolol and/or statins could be tested for efficacy in IH and other vascular anomalies in which SOX18 is expressed.
Images
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