Abstract 772: MicroRNA regulatory networks: Concomitant in situ detection of microRNA, mRNA and protein in cancer samples

Abstract

Abstract The canonical mode of action of microRNAs involves the binding to the 3'UTR of mRNAs thereby mediating repression of protein synthesis. MicroRNAs comprise an interesting new group of cancer biomarkers and may also be therapeutic targets in cancer and other diseases using antisense oligos (ASO). The visualization of potential molecular dynamics between a microRNA, its target mRNA and the effect of protein expression can be facilitated by combined detection in tissue sections. MicroRNAs, as well as ASOs, can be detected in tissue sections or cultured cells by in situ hybridization (ISH) using LNA probes. We have developed a novel ISH assay for microRNA detection with improved sensitivity and signal-to-noise that can be used with any LNA probe on both FFPE and frozen sections. The assay is based on double-labeled LNA™ probes and detection can be either fluorescence or chromogenic staining. We have combined the fluorescence assay with immunofluorescence, for double and triple staining. We also combined the microRNA ISH assay with mRNA in situ hybridization using the highly specific RNAscope probes. We show a variety of combinations, including examples of combined staining of microRNA-17, IL-1beta mRNA or TNF-alpha mRNA, and cytokeratin proteins in automated triple staining procedures of colon cancer samples. The focal expression of IL-1beta mRNA or TNF-alpha mRNA and the loss of microRNA-17 at the invasive front involving inflammatory cells and budding cancer cells is discussed. Citation Format: Boye Schnack Nielsen. MicroRNA regulatory networks: Concomitant in situ detection of microRNA, mRNA and protein in cancer samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 772.