BackgroundLenvatinib,　a　tyrosine　kinase　receptor　inhibitor,　has　emerged　as　a　frontline　therapeutic　strategy　for　the　management　of　advanced　hepatocellular　carcinoma　(HCC).　However,　the　modest　response　rate　observed　with　lenvatinib　and　the　rapid　emergence　of　chemoresistance　highlight　the　urgent　need　to　elucidate　the　underlying　molecular　mechanisms.　Herein　we　aimed　at　identifying　the　molecular　mechanisms　underlying　lenvatinib　resistance　in　HCC　and　investigated　the　efficacy　of　targeted　combination　therapies　to　surmount　this　chemoresistance.MethodsWe　utilized　CRISPR/Cas9　gene　knockout　screening　combined　with　transcriptome　sequencing　of　lenvatinib-resistant　HCC　cell　lines　to　identify　resistance-associated　genes.　PDGFRA　overexpression　was　validated　in　human　lenvatinib-resistant　HCC　cells.　We　further　corroborated　the　in　vitro　and　in　vivo　role　of　PDGFRA　in　lenvatinib　resistance　using　a　PDGFRA　inhibitor,　avapritinib,　employing　a　mouse　orthotopic　HCC　model,　patient-derived　organoids　(PDO),　and　patient-derived　xenografts　(PDX).　The　association　between　PDGFRA　expression　and　patient　prognosis　was　also　assessed.　Mechanistic　studies　were　conducted　to　elucidate　the　signaling　pathways　contributing　to　lenvatinib　resistance　mediated　by　PDGFRA.ResultsPDGFRA　overexpression　was　identified　as　a　key　determinant　of　lenvatinib-resistance　in　HCC　cells.　Consistently,　ectopic　PGDGFRA　overexpression　conferred　lenvatinib　resistance　upon　HCC　cells.　Treatment　with　the　PDGFRA　inhibitor　avapritinib　sensitized　HCC　cells　to　lenvatinib　in　mouse　orthotopic　HCC,　PDO,　and　PDX　models.　Increased　PDGFRA　expression　was　correlated　with　poor　prognosis　in　HCC　patients.　Mechanistic　studies　revealed　that　lenvatinib　treatment　or　PDGFRA　overexpression　promoted　HCC　resistance　through　the　PTEN/AKT/GSK-3　beta/beta-catenin　signaling　pathway.ConclusionsOur　findings　demonstrate　that　PDGFRA　overexpression　mediates　lenvatinib　resistance　in　HCC　and　that　targeting　PDGFRA　with　avapritinib,　surmounts　this　resistance.　Furthermore,　the　PTEN/AKT/GSK-3　beta/beta-catenin　pathway　was　implicated　in　lenvatinib　resistance,　providing　a　potential　therapeutic　strategy　for　HCC　patients　displaying　lenvatinib　resistance.　Further　clinical　studies　are　warranted　to　validate　these　findings　and　to　explore　the　clinical　application　of　PDGFRA-targeted　therapies　in　HCC　treatment.