MiRNA expression profiling of mouse colon cancer stem cells: A tumor-specific signature traceable along colorectal cancer progression with prognostic value in human colon cancer

Abstract

BackgroundThe definition of cancer stem cells (CSC) still lacks conclusive experimental evidence. Colorectal cancer (CRC) EphB2 and EphA2 cells have been correlated to stem-like properties and tumor malignancy. Here, we investigated a panel of miRNA involved in the self-renewal and cell fate during cancer development using murine CRC EphA2 and EphB2 sorted cells and tumor tissues as well as public datasets of hCRC data. MethodsFACS-isolated murine EphA2high and EphB2high cells were analyzed by gene expression and IHC analyses in order to characterize the stem-like/differentiation phenotype. miRNAs expression profiling was performed using TaqMan LDA both on murine sorted cells and tissue and validated on public hCRC datasets (TCGA and GEO). ResultsmiRNAs differentially expressed in murine tumor EphA2/EphB2 cells and tissues were found to orchestrate functions related to stem-like properties or to proliferation, metastasis and drug-resistance. Particularly, the EphA2 cells showed a molecular pattern reflecting the activation of EphA2 and EGFR pathways and a coherent dysregulation of mir26b and mir-200a. This pattern displayed prognostic significance for stage I–III CRC. In patients with stage IV and WT KRAS, EphA2/Efna1/Egfr gene expression status was significantly associated with poor response to cetuximab treatment. EphA2 and EGFR overexpression showed a combined effect relative to cetuximab resistance, independently from KRAS mutations. The EphA2/EphB2-specific signatures resulted to be clinically relevant. ConclusionsThese data provide a comprehensive miRNAs signature implicated in the regulation of tumorigenesis, stemness and drug resistance that could be exploited for diagnosis, therapeutic design and could be proposed as novel CRC prognostic biomarkers.