Sporadic arteriovenous malformations (AVMs) are congenital disorders of blood vessels which present with strokes, life threating haemorrhages, pain and/or disfigurement. Current management options are limited to high-risk, invasive procedures which are often ineffective. Recent genetic studies have identified post-zygotic variants in three genes of the MAPK/ERK pathway as causative in a third of cutaneous AVM patients. The variants identified are drivers in many cancers, and pharmacologically targetable with repurposing of licensed inhibitors. Although some earlier work using MAPKi inhibitors showed promise in in vitro and in vivo experiments, anecdotal case reports results are variable. We hypothesised that an unbiased drug screen could provide an invaluable approach for the identification of novel therapies or combinations. A CRISPR protocol was developed and optimised to knock-in point mutations in immortalised human endothelial cell line HUVEC/TERT2, generating a KRAS c.35G>T (p.G12V) line to be compared to its KRAS wildtype (WT) control. Characterisation of intracellular signaling pathway activation, global gene expression profiles, as well as cellular characteristics was undertaken, revealing increased MAPK pathway activation as well as proliferation. Extensive optimisation of tissue culture conditions, as well as optimisation of time points for measurement, allowed determination of the most robust readouts for a FDA-approved high throughput drug-screen, namely proliferation as the primary endpoint. A further readout was created by generating the AVM cell lines expressing the genetically encoded FRET-based ERK activity biosensor, EKAREV, to be used as a secondary screening round. This novel model of KRAS-mutant AVM is an important step in the study of this disease.

ESDR270 - In vitro modelling and high-throughput drug screening for sporadic arteriovenous malformations

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.