Effects of melatonin and 17beta-estradiol treatments in CRISPR/Cas9 gene editing mice with induced mammary carcinoma

• Grant number: 25/08621-1
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: September 08, 2025
• End date: September 07, 2026
• Field of knowledge: Health Sciences - Medicine - Maternal and Child Health
• Principal Investigator: Edmund Chada Baracat
• Grantee: Bruna Cristine de Almeida
• Supervisor: Carol Fuzeti Elias
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: University of Michigan, United States
• Associated to the scholarship: 22/04174-2 - Effects of melatonin and 17beta-estradiol on the expression profile of microRNAs and their targets in invasive ductal carcinoma of the breast, BP.PD

Abstract

MicroRNAs (miRNAs) are small non-coding RNAs that act in gene expression regulation. Studies show that its abnormal expression is associated with cellular transformation, compromised therapeutic response, and worse prognosis in breast carcinoma because they act in gene regulation of important signaling pathways. It is well known that estrogen (E2), as well as their receptors, play a crucial role in the development and maintenance of breast homeostasis and their imbalance can lead to cancer appearance. Nowadays, there is great interest in the identification of modulating substances of miRNAs expression that would serve as targeted therapy in several diseases. In this context, melatonin has been described as a miRNAs regulator, inhibiting the risk of cellular malignancy. The present study aims: 1) to identify differentially expressed miRNAs in invasive ductal carcinoma (IDC) cell lines treated with melatonin alone or associated with E2; 2) to identify the main target genes with differential regulation in treated cells; 3) Functionally validated the role of interested miRNAs in the E2 regulation mediated by melatonin by genetic manipulation in vitro and in vivo. For this purpose, CDI cell lines, T47D, MCF7 (luminal A types), and MDA-MB-231 (triple-negative type) will be used after melatonin and E2 treatment, and tumor samples from patients with the same molecular types will be evaluated. miRNAs expression profile of and target genes will be evaluated in cells and tissue using the qRT-PCR array analysis platforms. Functional validation will be performed using siRNAs (silencing) or mimics (induction), while the effect of treatments of genetic manipulation on the cells' phenotype will be analyzed by cellular proliferation, migration, and invasion assays. Based on the results obtained, a target gene will be selected for genetic manipulation (CRISPR-Cas9) and inoculation in the animal model. This step will be carried out in collaboration with the University of Michigan Ann Arbor, under Prof. Dr. Carol Fuzeti Elias's supervision. The innovative proposal of this project is the evaluation of the genetic and epigenetic effects of the melatonin treatment after cell induction with E2 (isolated and combined) in ICD, which is part of a Thematic Project (2018/24224-9) and the FAPESP postdoctoral project no. 2022/04174-2 funded by this promotion agency. The results obtained may bring new and relevant information about the biology of these tumors and their clinical management. (AU)