Hedgehog inhibition mediates radiation sensitivity in mouse xenograft models of human esophageal adenocarcinoma.

• Main Authors: Jennifer Teichman, Lorin Dodbiba, Henry Thai, Andrew Fleet, Trevor Morey, Lucy Liu, Madison McGregor, Dangxiao Cheng, Zhuo Chen, Gail Darling, Yonathan Brhane, Yuyao Song, Osvaldo Espin-Garcia, Wei Xu, Hala Girgis, Joerg Schwock, Helen MacKay, Robert Bristow, Laurie Ailles, Geoffrey Liu
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2018-01-01
• Series: PLoS ONE
• Online Access: http://europepmc.org/articles/PMC5929523?pdf=render

BACKGROUND:The Hedgehog (Hh) signaling pathway is active in esophageal adenocarcinoma (EAC). We used a patient-derived murine xenograft (PDX) model of EAC to evaluate tumour response to conventional treatment with radiation/chemoradiation with or without Hh inhibition. Our goal was to determine the potential radioresistance effects of Hh signaling and radiosensitization by Hh inhibitors. METHODS:PDX models were treated with radiation, chemotherapy or combined chemoradiation. Tumour response was measured by growth delay. Hh transcript levels (qRT-PCR) were compared among frozen tumours from treated and control mice. 5E1, a monoclonal SHH antibody, or LDE225, a clinical SMO inhibitor (Novartis®) inhibited Hh signaling. RESULTS:Precision irradiation significantly delayed xenograft tumour growth in all 7 PDX models. Combined chemoradiation further delayed growth relative to either modality alone in three of six PDX models. Following irradiation, two of three PDX models demonstrated sustained up-regulation of Hh transcripts. Combined LDE225 and radiation, and 5E1 alone delayed growth relative to either treatment alone in a Hh-responsive PDX model, but not in a non-responsive model. CONCLUSION:Hh signaling mediates the radiation response in some EAC PDX models, and inhibition of this pathway may augment the efficacy of radiation in tumours that are Hh dependent.