TY - JOUR AB - MicroRNA (miRNA/mir)‑490‑3p has been defined as a tumor suppressor in different types of cancer, including breast cancer. However, miR‑490‑3p has been shown to function as a tumor suppressor and promoter in a context‑dependent manner in hepatocellular and lung cancer. Contrary to previous studies, the present study revealed that miR‑490‑3p expression was significantly higher in invasive ductal carcinoma (IDC) tissue specimens, the most common form of breast cancer, compared to tumor‑adjacent normal tissue specimens (n=20). Its expression was also higher in the more metastatic breast cancer cell line, MDA‑MB‑231, compared to the non‑metastatic breast cancer cell line, MCF7, and the moderately metastatic breast cancer cell line, MDA‑MB‑468. The expression of miR‑490‑3p was induced following transforming growth factor (TGF)‑β‑induced epithelial‑to‑mesenchymal transition (EMT) in MCF10A cells. Gain‑and loss‑of‑function assays revealed that the expression of miR‑490‑3p regulated the proliferation, colony formation, EMT, migration and invasion in vitro, but not the apoptosis of MDA‑MB‑468 and MDA‑MB‑231 cells. The knockdown of miR‑490‑3p expression in MDA‑MB‑231 cells inhibited experimental metastasis in a tumor xenograft assay. As in lung cancer, miR‑490‑3p was found to target and downregulate the expression of the tumor suppressor RNA binding protein poly r(C) binding protein 1 (PCBP1). PCBP1 protein and miR‑490‑3p expression inversely correlated in patients with ductal carcinoma in situ (DCIS; n=10; no nodal involvement) and IDC (n=10; different stages of metastatic progression) with a significantly higher miR‑490‑3p expression in patients with IDC compared to those with DCIS. The expression of miR‑490‑3p was negatively associated with both overall and disease‑free survival in the patients with breast cancer included in the present study. On the whole, the results confirm a pro‑metastatic role of miR‑490‑3p in IDC, establishing it as a biomarker for disease progression in these patients. AD - Department of Breast Medical Oncology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin 300060, P.R. China Department of Rheumatology and Immunology, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China Department of Pharmacy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin 300060, P.R. China Department of Medicine, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China Department of Human Resources, Tianjin Hospital, Tianjin 300211, P.R. China AU - Lu,Ning AU - Zhang,Mei AU - Lu,Lu AU - Liu,Yan‑Zhao AU - Zhang,Hai‑Hong AU - Liu,Xiao‑Dong DA - 2021/02/01 DO - 10.3892/or.2020.7880 EP - 716 IS - 2 JO - Oncol Rep KW - poly r(C) binding protein 1 miR‑490‑3p breast cancer epithelial‑to‑mesenchymal transition metastasis PY - 2021 SN - 1021-335X 1791-2431 SP - 706 ST - miRNA‑490‑3p promotes the metastatic progression of invasive ductal carcinoma T2 - Oncology Reports TI - miRNA‑490‑3p promotes the metastatic progression of invasive ductal carcinoma UR - https://doi.org/10.3892/or.2020.7880 VL - 45 ER -