Abstract 3547: MicroRNA-496 inhibits triple negative breast cancer cell proliferation by targeting DEL-1

Abstract

Abstract Background and Objectives: Del-1 is linked to the pathogenesis of various cancers including breast cancer; however, the regulation of Del-1 expression remains unclear. The current study investigated how microRNA-496 (miR-496) regulates Del-1 expression in triple negative breast cancer (TNBC). Methods: Del-1 mRNA and miR-496 were measured by quantitative PCR in breast cancer cells (MDA-MB-231, MCF7, SK-BR3, and T-47D) and tissues from 30 patients with TNBC. The effects of miR-496 on cell proliferation, migration, and invasion were determined in MTT, wound healing, and Matrigel Transwell assays, respectively. Results: In MDA-MB-231, miR-496 levels were remarkably low and Del-1 mRNA was higher compared to other breast cancer cell lines. Luciferase reporter assays revealed that miR-496 binds the 3′-UTR of Del-1 and that Del-1 expression is downregulated by miR-496 mimics. Furthermore, miR-496 inhibited the proliferation, migration, and invasion of MDA-MB-231 cells. The effects of miR-496 on cell proliferation were additive with those of miR-137, another miRNA that regulates Del-1 expression. Moreover, in the 30 TNBC specimens, miR-496 was downregulated (P < 0.005) and the levels of Del-1 in the plasma was significantly elevated as compared to normal controls (P = 0.0142). TCGA data showed the correlation of miR-496 expression with better overall survival in patients with early TNBC. Conclusions: In in silico and in vitro analyses, we showed that Del-1 is a target of miR-496 in TNBC and thereby affects cancer progression. Our findings suggest that miR-496 and Del-1 might act as modulating factors in TNBC and are new biomarkers for patients with TNBC. Citation Format: Dong Won Baek, Jae-Hwan Jeong, Soo Jung Lee, Jiyeon Lee, Yee Soo Chae, Wan WooK Kim, Jieun Kang, Ho Yong Park, Jin Hyang Jung, Ji Yun Jeong, Ji Young Park, Keon Uk Park. MicroRNA-496 inhibits triple negative breast cancer cell proliferation by targeting DEL-1 [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 3547.