New predictive factors identified by molecular study in chemoresistant human and canine mammary carcinoma cells

• Grant number: 19/24001-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: June 01, 2021
• End date: September 30, 2024
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Carlos Eduardo Fonseca Alves
• Grantee: Patrícia de Faria Lainetti
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Mammary gland tumors in dogs are common mainly in elderly and unneutered animals. Among the diagnosed cases of neoplasms, more than 50% are malignant. Mammary neoplasms in dogs are greatly important, due to the high incidence in these animals. Beyond that, they are considered a comparative model of study for mammary neoplasms of women. Similarities between the tumors of the two species include spontaneous appearance, tumor evolution, biological behavior and the expression of some receptors. Chemotherapy resistance is one of the main reasons for response failure to cancer treatment in women and compromises the choice of future protocols in case of recurrence. In dogs it is difficult to choose the best chemotherapy for breast cancer, as these drugs have no proven efficacy in tumor remission and also have the phenomenon of chemoresistance. The present study aims to evaluate the doxorubicin resistance of women and dog mammary tumor cell cultures in order to identify new therapeutic targets. Doxorubicin resistance will be induced in two breast tumor cell lines in women (HCC1954 and MCF7) and in 5 primary breast tumor cultures in dogs. In vitro cultured cells will be submitted to doxorubicin chemoresistance and SNP array analysis will be performed to select chemoresistance-related SNPs and these will be validated in a group of independent samples, 250 paraffin-block canine breast tumors, and for for women, SNPs will be validated in the breast carcinoma sample database. The validation of female breast tumor samples will also be performed by PCR assay. Subsequently, predictive SNPs will be selected and the expression of therapeutic targets in cell culture samples will be confirmed by Western blotting technique. After choosing therapeutic targets, the selected drugs will be tested on the chemoresistant cells. MTT assay {[3- (4,5-dimethylthiazol-2yl) -2,5-diphenyl tetrazolium] bromide} will be performed for IC50 determination and different in vitro assays will be performed to verify the antitumoral effect of the selected drugs, as evaluation colony formation and tumorspheres; 3D culture and PCR array gene expression assay. (AU)