566 Short-term, incidental sun-exposure causes epigenetic drift which is significantly reduced through daily SPF use and can be replicated in an ex-vivo skin model

Abstract

Introduction: Up to now, UV-induced epigenetic drift has only been shown to occur in skin that has experienced decades of chronic sun exposure and is associated with large regions of hypo-methylation1. Objectives: 1) To determine if sun-induced epigenetic drift occurs after 5 months of incidental sun-exposure, and if a sun-protection factor (SPF) product can protect against such drift. 2) To develop a 1 week ex-vivo model that mirrors 5-month in-vivo UV-induced epigenetic drift. Materials and Methods: A single center, IRB-approved, biopsy study involving 60 females, age 25-45 with Fitz skin types II-III. Subjects applied a SPF product to the face and one arm over the course of five months, tracked with clinical instrumental measurements, and biopsies taken from both arms at baseline and at the end of the study. DNA was isolated from the biopsies and methylation levels interrogated using a pre-selected, UV-sensitive set of probes from Illumina methylation arrays. Anex-vivo, repeat UV, skin model was developed to assess epigenetic drift and protection. Results: Instrumental measurements confirmed that the untreated and treated arms had melanin changes consistent with UV exposure and protection respectively. Incidental, short-term sun-exposure led to a significant epigenetic drift and in the direction expected by chronic sun-damage; SPF product-use significantly reduced the drift. An almost identical epigenetic drift and SPF protection were detected in the ex-vivo model. Conclusions: This the first study to demonstrate that UV-induced epigenetic drift occurs even during incidental, short-term sun-exposure and that a SPF product can significantly reduce the drift, reinforcing the importance of daily sun-protection. References 1 Vandiver AR, Irizarry RA, Hansen KD et al. Age and sun exposure-related widespread genomic blocks of hypomethylation in nonmalignant skin. Genome Biol 2015; 16: 80.