miRNAs associated to breast cancer and metabolic syndrome.

FARRÉ PL; DALTON GN; PICCIONI F; MASSILLO CL; SCALISE G; DE SIERVI A.

Bernal

Simposio; II Argentine Meeting on Biology of Non-coding RNAs; 2018

Universidad Nacional de Quilmes

Breast cancer (BrCa) is the main cause of death in women for cancer worldwide. The use of microRNAs (miRNAs) shows up as an alternative in early BrCa detection. miRNAs could be useful as biomarkers for diagnostic, prognostic and/or therapeutic targets given that they are found circulating in body fluids and they are associated to the presence of certain types of tumors. Metabolic syndrome (MeS) is a cluster of physiopathological disorders and an important risk factor in the development of certain diseases including BrCa, since it correlates with higher grade tumors, an increased recurrence and the development of metastasis.The aim of this work was to identify miRNAs in BrCa xenografts developed in MeS mice in order to identify them in mice?s peripheral blood. For the in vivo model, four weeks old female Balb/c mice (n=30) were chronically fed with high fat (HFD 6040 Kcal/kg, n=15) or control (CD, 4660 Kcal/Kg, n=15) diets. After 15 weeks, 10 animals of each group were inoculated s.c. with 1x104 4T1 cells on the mammary fat pad. When tumors were palpable, 5 HFD and 5 CD mice were sacrificed (Early Stage) and blood and tumor samples were collected for further analysis. The other group of inoculated animals were sacrificed when their tumors reached a volume of approximately 600 mm3 (Advanced Stage) with the non-tumor mice (Control) and blood and tumors were collected for further analysis.Total RNA was extracted from tumor and plasma and the expression of several miRNAs selected from literature associated to BrCa or MeS were analyzed by stem-loop RT-qPCR technique. In this work, we found that HFD increased mice weigh and tumor size. Moreover, after miRNA RT-qPCR from xenografts, we identified two groups of BrCa associated miRNAs; one group includes 125b-5p, 21-5p, 106b-5p and 34a-5p miRNAs, which were increased in mice with advanced stage of BrCa, sustaining this difference between the CD and HFD group in almost all the cases. The other group was formed by 10b-5p, 138-5p, 143-3p, 127-3p and 195-5p miRNAs, which were diminished in mice with advanced stages of BrCa, and they also kept this difference in each HFD and CD group. Remarkably, miR-195-5p was also modulated by MeS. Additionally, MeS increased its expression in BrCa early stage. We also identified some of these miRNAs circulating in plasma from these mice. These results will allow us, in the future, to identify circulating miRNAs associated to BrCa and MeS and establish the bases for studies that use plasma from patients with these diseases and generate new candidates as diagnostic biomarkers.