Paired-like Homeodomain Transcription factor 2 expression by breast cancer bone marrow disseminated tumor cells is associated with early recurrent disease development

Abstract

The presence of disseminated tumor cells (DTCs) in the bone marrow (BM) of breast cancer patients is prognostic for early relapse. In the present study, we analyzed the gene expression profiles from BM cells of breast cancer patients to identify molecular signatures associated with DTCs and their relevance to metastatic outcome. We analyzed BM from 30 patients with stage II/III breast cancer by gene expression profiling and correlated expression with metastatic disease development. A candidate gene, PITX2, was analyzed for expression and phenotype in breast cancer cell lines. PITX2 was knocked down in the MDAMB231 cell lines for gene expression analysis and cell invasiveness. Expression of various signaling pathway molecules was confirmed by RT–PCR. We found that the expression of Paired-like Homeobox Transcription factor-2 (PITX2) is absent in the BM of normal healthy volunteers and, when detected in the BM of breast cancer patients, is significantly correlated with early metastatic disease development (p = 0.0062). Suppression of PITX2 expression significantly reduced invasiveness in MDAMB231 cells. Three genes—NKD1, LEF1, and DKK4—were significantly downregulated in response to PITX2 suppression. Expression of PITX2 in BM of early-stage breast cancer patients is associated with risk for early disease recurrence. Furthermore, PITX2 likely plays a role in the metastatic process through its effect on the expression of genes associated with the Wnt/beta-Catenin signaling pathway.Electronic supplementary materialThe online version of this article (doi:10.1007/s10549-015-3576-z) contains supplementary material, which is available to authorized users.

Clinical Validation of PITX2 DNA Methylation to Predict Outcome in High-Risk Breast Cancer Patients Treated with Anthracycline-Based Chemotherapy

“…Methylation of the PITX2 gene promoter leads to epigenetic silencing of this transcription factor and subsequent changes in molecular signaling. DNA methylation plays a crucial role in the development and progression of a variety of cancers, including breast cancer [5,6,7,8,9]. …”

The Predictive Value ofPITX2DNA Methylation for High-Risk Breast Cancer Therapy: Current Guidelines, Medical Needs, and Challenges

“…PITX2 (paired-like homeodomain transcription factor 2, also known as pituitary homeobox 2) is a transcription factor, which is involved in the morphogenesis of anterior structures, such as eyes and teeth. PITX2 is involved in pituitary-specific gene regulation and left-right patterning during embryonic and organogenic development [ 58 , 59 ]. PITX2 has three different isoforms, leading to three different proteins (PITX2A, PITX2B, and PITX2C), which differentially regulate transcription of their target genes [ 60 ].…”

“…PITX2 has three different isoforms, leading to three different proteins (PITX2A, PITX2B, and PITX2C), which differentially regulate transcription of their target genes [ 60 ]. Two promoters (P1 and P2) are operational: P2 drives transcription of two mRNA variants, leading to the PITX2A and B proteins; P1 drives the third transcript variant encoding the C protein [ 58 , 61 , 62 ]. Expression of isoforms 1 and 2 is regulated by the Wnt/ β -catenin pathway, and expression of isoform 3 is regulated by TGF-β family members [ 48 , 58 ].…”

“…Two promoters (P1 and P2) are operational: P2 drives transcription of two mRNA variants, leading to the PITX2A and B proteins; P1 drives the third transcript variant encoding the C protein [ 58 , 61 , 62 ]. Expression of isoforms 1 and 2 is regulated by the Wnt/ β -catenin pathway, and expression of isoform 3 is regulated by TGF-β family members [ 48 , 58 ]. Both the Wnt/ β -catenin pathway and the TGF-β pathway play important roles in carcinogenesis, but the results from Pillai et al support the notion that PITX2 plays a role in mediating invasiveness of cancer cells through the Wnt/ β -catenin pathway [ 58 ].…”

Developmental signaling pathways regulating mammary stem cells and contributing to the etiology of triple-negative breast cancer

“…Also, the Pitx2 isoform 1 transcription factor, which is a target gene in the Nodal/Cripto-1 and Wnt/β-catenin signaling pathways, is known to contribute to the invasion of BC cells. Pitx2 was found in the bone marrow of BC patients and was significantly associated with metastatic BC development [ 83 ].…”