Gene expression profiling of breast carcinoma associated fibroblast following treatment with vitamin D

Author(s)

Laura Tojeiro Campos

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2010-12-03

Examining board members

Maria Mitzi Brentani; Dirce Maria Carraro; Ubiratan Fabres Machado

• Advisor: Maria Mitzi Brentani

Abstract

The role of 1,25(OH)2D3 (calcitriol), the active metabolite of Vitamin D, in breast cancer has been extremely explored. Antiproliferative, prodifferentiating and anti-inflammatory effects of calcitriol have been reported in breast cancer. Expression profile by microarray analysis has identified many responsive genes modulated by calcitriol and analogs. The majority of them defined to date are based on studies using breast cancer cell lines or mouse models. Little is known about the action of calcitriol in the others cell types present into the tumor microenvironment. Cancerassociated fibroblasts (CAFs), the principal cell component of the tumor microenvironment, play a central role in the complex process of tumour stroma interaction and consequently in all breast cancer tumorigenesis steps. The aim of our study was to identify key genes that are regulated by calcitriol in breast cancer associated fibroblasts. Primary fibroblasts cell cultures from five breast cancer samples were established and then phenotyping characterized by a set of markers. The occurrence of vitamin D receptor was confirmed in all samples and fibroblasts were divided in three groups: one control group and two treatment groups, 0.5 nM and 100 nM of calcitriol during 24 hours. The determination of gene expression profile was performed by oligo microarray technology using the GeneChip Human Genome U133 Plus 2.0 (Affymetrix). Control and 0.5 nM calcitriol analysis resulted in 274 differentially expressed genes, many of then involved in biological processes as apoptosis and cell migration. The 161 differentially expressed genes obtained from comparison between groups control and 100 nM calcitriol treatment were functionally involved in several biological processes. The most significantive processes regulated by VD3 in breast CAFs were the inflammatory and immune responses, suggesting that the anti-inflammatory action of calcitriol, yet reported in several studies using epithelial breast cancer cells, may also been applied to breast cancer associated fibroblasts (AU)