Downregulation of circulating miR 802-5p and miR 194-5p and upregulation of brain MEF2C along breast cancer brain metastasization

Marta Sereno, János Haskó, Kinga Molnár, Sarah J. Medina, Zita Reisz, Rui Malhó, Mafalda Videira, László Tiszlavicz, Stephanie A. Booth, Imola Wilhelm, István A. Krizbai, Maria Alexandra Brito

Research output: Contribution to journalArticle

Abstract

Breast cancer brain metastases (BCBMs) have been underinvestigated despite their high incidence and poor outcome. MicroRNAs (miRNAs), and particularly circulating miRNAs, regulate multiple cellular functions, and their deregulation has been reported in different types of cancer and metastasis. However, their signature in plasma along brain metastasis development and their relevant targets remain undetermined. Here, we used a mouse model of BCBM and next-generation sequencing (NGS) to establish the alterations in circulating miRNAs during brain metastasis formation and development. We further performed bioinformatics analysis to identify their targets with relevance in the metastatic process. We additionally analyzed human resected brain metastasis samples of breast cancer patients for target expression validation. Breast cancer cells were injected in the carotid artery of mice to preferentially induce metastasis in the brain, and samples were collected at different timepoints (5 h, 3, 7, and 10 days) to follow metastasis development in the brain and in peripheral organs. Metastases were detected from 7 days onwards, mainly in the brain. NGS revealed a deregulation of circulating miRNA profile during BCBM progression, rising from 18% at 3 days to 30% at 10 days following malignant cells’ injection. Work was focused on those altered prior to metastasis detection, among which were miR-802-5p and miR-194-5p, whose downregulation was validated by qPCR. Using targetscan and diana tools, the transcription factor myocyte enhancer factor 2C (MEF2C) was identified as a target for both miRNAs, and its expression was increasingly observed in malignant cells along brain metastasis development. Its upregulation was also observed in peritumoral astrocytes pointing to a role of MEF2C in the crosstalk between tumor cells and astrocytes. MEF2C expression was also observed in human BCBM, validating the observation in mouse. Collectively, downregulation of circulating miR-802-5p and miR-194-5p appears as a precocious event in BCBM and MEF2C emerges as a new player in brain metastasis development.

Original languageEnglish
Pages (from-to)520-538
Number of pages19
JournalMolecular Oncology
Volume14
Issue number3
DOIs
Publication statusPublished - Mar 1 2020

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Keywords

  • bioinformatics
  • brain metastasis
  • breast cancer
  • microRNAs
  • myocyte enhancer factor 2C
  • next-generation sequencing

ASJC Scopus subject areas

  • Molecular Medicine
  • Genetics
  • Oncology
  • Cancer Research

Cite this

Sereno, M., Haskó, J., Molnár, K., Medina, S. J., Reisz, Z., Malhó, R., Videira, M., Tiszlavicz, L., Booth, S. A., Wilhelm, I., Krizbai, I. A., & Brito, M. A. (2020). Downregulation of circulating miR 802-5p and miR 194-5p and upregulation of brain MEF2C along breast cancer brain metastasization. Molecular Oncology, 14(3), 520-538. https://doi.org/10.1002/1878-0261.12632