Figure 2.

Circulating miRNAs alterations are related with their brain parenchyma deregulation in early stages of breast cancer brain metastases formation. 4T1 cells or vehicle (control) were inoculated into the carotid artery of female Balb/c mice and after 3 days, whole blood was collected, and brains harvested after sacrifice. Plasma was processed for real-time quantitative PCR (RT-qPCR) and sections of cranial hippocampus were processed for in situ hybridization (ISH) analysis of the different miRNAs. RT-qPCR analysis highlighted the downregulation of miR-802-5p and miR-194-5p, and the up-regulation of miR-92a-1-5p, miR-205-5p and miR-181a-1-3p in 4T1-injected mouse plasma, with the results presented as fold-change vs. control (A). ISH analysis validated the same miRNAs downregulation and upregulation, as shown by the expression of these miRNAs in bluish stained brain cells (B), and ascertained by semi-quantitative analysis of the number of each miRNA positive cell per field (C). Statistical differences are denoted as * p < 0.05, ** p < 0.01, *** p < 0.001 vs. control by two-tailed unpaired Student’s t-test. Data represented are means ± SEM, n = 3.