Abstract P6-05-10: MicroRNA-137 inhibits cancer progression by targeting DEL-1 in triple negative breast cancer cells, MDA-MB-231

Background: This study aimed to investigate the function of microRNA-137 in Del-1 expression in triple negative breast cancer (TNBC) cells and tissues. Methods: The Del-1 mRNA and microRNA levels were measured using a qRT-PCR in breast cancer cells (MDA-MB-231, MCF7, SK-BR3, and T-47D) and tissues from 20 patients with TNBC. The effects of miR-137 on cell proliferation, migration, and invasion were determined using MTT, wound healing, and Matrigel Transwell assays. Results: microRNA-137 (miR-137) levels were remarkably low and Del-1 mRNA expression was higher in MDA-MB-231 cells as compared to other breast cancer cell lines. The luciferase reporter assay revealed that miR-137 binds directly at the 3¢-UTR of Del-1 and that Del-1 expression was downregulated by miR-137 mimics and rescued by its inhibitors. Furthermore, miR-137 inhibited the cell proliferation, migration, and invasion of MDA-MB-231 cells. Moreover, among the 30 TNBC specimens, miR-137 was downregulated (p Conclusions: In conclusion, miR-137 regulates Del-1 expression in TNBC via directly binding to the Del-1 gene, and thereby affects cancer progression. This suggests that miR-137 may be a new therapeutic biomarker for patients with TNBC. Keywords: Del-1, triple negative breast cancer, miR-137, biomarker Citation Format: Chae YS, Baek DW, Lee IH, Lee SJ, Lee RK, Lee J, Jung J, Park H, Jeong J-H, Kang J, Park J. MicroRNA-137 inhibits cancer progression by targeting DEL-1 in triple negative breast cancer cells, MDA-MB-231 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-05-10.