Abstract 3431: The oncogenic role of miR-150-5p in triple-negative breast cancer
Authors: Bruna M. Sugita, Yara Zabala, Aline Fonseca, Rodrigo Almeida, Yuriy Gusev, Simina Boca, Iglenir J. Cavalli, Enilze M. Ribeiro, Luciane R. Cavalli
Journal: Cancer Research (2017)

Abstract Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that confers disease recurrence, treatment resistance and high mortality rates. MicroRNAs are a class of noncoding RNAs, that when dysregulated, impact tumorigenesis through the control of the expression of multiple mRNA targets involved in critical cancer signaling pathways. MiR-150-5p has been shown to control the expression of several driver oncogenes and/or tumor suppressor genes involved in these critical pathways. Its pattern of expression varies according to the cancer type; it has been observed mostly downregulated in hematological diseases and GI cancers, and upregulated in hormonal dependent cancers, such as prostate and breast cancer. The main objective of this study was to assess the patterns of expression of miR-150-5p in TNBC and determine its functional role in affecting the tumor phenotype. Archived paraffin samples of 113 patients with ductal breast carcinoma (56 of the TNBC and 57 of the non-TNBC subtype) and 49 adjacent normal tissue (ANT), obtained from the the pathology tumor bank of Lombardi Comprehensive Cancer Center, Washington DC, were profiled for miRNA using the wide-genome Nanostring platform and a Taqman specific miRNA-150-5p assay. Significant overexpression levels of miRNA-150-5p were observed in the tumor tissues when compared to the ANT and in the TNBC cases when compared to the non-TNBC cases, demonstrating its tumor and TNBC subtype specificity, respectively. Overexpressed levels of miRNA-150-5p were also preferentially observed in the TNBC cases from patients that presented with LN metastasis and breast cancer recurrence, indicating its association with poor prognosis. Interestingly, the TNBC of African-American patients, which is the ethnic group mostly affected by this cancer subtype, presented overexpression levels of this miRNA when compared to the Non-Hispanic White patients. Functional analysis performed in the TNBC cell lines, MDA-MB-231 and HCC1806, showed after transfection with miR-150-5p inhibitor, reduced levels on cell proliferation, clonogenicity, migration, drug resistance and expression of the EMT promoter markers, SLUG and SNAIL. These findings, indicate an oncogenic type of action of miRNA-150-5p in TNBC. In summary, miRNA-150-5p is upregulated in TNBC clinical cases in association with poor prognostic parameters and its functional inhibition, directly confers to the cells a reduction of their tumorigenic phenotype. Funding: This project was supported by the Georgetown University Center of Excellence in Regulatory Science and Innovation (CERSI U01FD004319), a collaborative effort between the university and the U.S. Food and Drug Administration to promote regulatory science through innovative research and education. This research does not necessarily reflect the views of the FDA. Scholarship to B.S. was provided by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). Citation Format: Bruna M. Sugita, Yara Zabala, Aline Fonseca, Rodrigo Almeida, Yuriy Gusev, Simina Boca, Iglenir J. Cavalli, Enilze M. Ribeiro, Luciane R. Cavalli. The oncogenic role of miR-150-5p in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3431. doi:10.1158/1538-7445.AM2017-3431