Prostacyclin synthase (PTGIS) expression and epigenetic regulation in non-small cell lung cancer (NSCLC)

e22160 Background: Prostacyclin synthase (PTGIS) inhibits platelet aggregation and promotes vasodilation. Overexpression of this gene has been shown to inhibit lung cancer growth in a mouse model. Hypermethylation of the PTGIS promoter resulting in downregulation of PTGIS expression has been implicated in colorectal cancer. In this study we have examined both the expression patterns and epigenetic regulation of PTGIS in NSCLC. Methods: DNA/RNA and protein was extracted from matched tumour/normal samples (Thoracic Oncology Research Group BioBank, St James Hospital). PTGIS in these samples and a panel of retrospective resected lung samples was examined by immunohistochemistry and western blotting. A panel of NSCLC cell lines were treated with inhibitors to histone deacetylases (HDi) and DNA methyltransferases (DNMTi) and PTGIS expression examined by RT-PCR. Chromatin immunoprecipitation (ChIP) was used to examine changes to the PTGIS promoter in response to HDi. Results: PTGIS was found to have variable exp...