PO-278 Distinctive role of dysregulated miRNAs and mRNAs in chordoma cancer stem cells

Abstract

IntroductionChordoma is a rare, resistant bone tumour thought to be arised from remnants of embryonic notochord. Cancer stem cells (CSCs) are associated with tumorigenesis, recurrence and resistance in cancers. Therefore, chordoma CSCs are possible targets for chordoma treatment. According to our previous study, CD133 and CD15 expressing chordoma cells shows stem-like cell properties however miRNA and mRNA profiling of these cells have not been determined yet.Material and methodsIn this study, we determined dysregulated miRNAs in CSCs of chordoma via miRNA microarray and validated these miRNAs with qPCR. Hereupon, validated miRNAs was transfected chordoma cell lines transiently and identified their role in proliferation, apoptosis, migration and invasion capacities. mRNA microarray analysis was also carried out to examine dysregulated pathways in chordoma CSCs. Lastly, relationship between clinicopathological features and dysregulated miRNAs (and their targets) has been evaluated in 21 chordoma patientsResults and discussionsCD133 +CD15+cells in chordoma cell lines exhibits CSC phenotype with increased CSC-related gene expression and invasion-migration ability. miRNA microarray analyses indicated that 238 miRNAs (15 upregulated, 223 downregulated) were differentially expressed in chordoma Cancer Stem Cells (CSCs). mRNA microarray results also suggested that chordoma CSCs differentially expressed 1064 genes (176 upregulated, 888 downregulated). We then demonstrated that Wnt5a, TGF-α, Btg2 and Mycbp genes which are relevant to CSC-related pathways were direct targets of miR-140–3 p, miR-148a-3p, miR-210–5 p and miR-574–5 p, respectively. Finally, we determined that miR-140–3 p and miR-148a-3p expression was correlated with Ki67, miR-140–3 p and TGFa expressions was correlated with p53, and also MYCBP expression was positively correlated with tumour volume. Finally, mRNA microarray analysis showed that various pathways including Cell cycle, DNA replication, Spliceosome, Mismatch repair, FoxO signalling, P53 Signalling, Hippo signalling, BRCA2 and ATR in Cancer Susceptibility, and Apoptotic DNA fragmentation and tissue homeostasis were dysregulated in chordoma CSCs.ConclusionThrough these findings, we concluded that chordoma CSCs have distinctive miRNA and mRNA profiles and this situation can regulate stemness properties of chordoma CSCs.