O2-9-2 - Expression and significance of oncogenic miRNAs (21,17,10 A&B) with breast cancer stem cell in breast carcinoma patients

Abstract

Background: Breast cancer is a complex disease with heterogeneity and several studies have been conducted to identify the miRNAs that are differentially expressed and regulate breast cancer initiation and progression. Oncogenes regulating miR 21 miR10 a&b and miR 17 are involved in various signalling pathways and promote carcinogenesis and Cancer stem cells (CSCs) have been proposed as the driving force of tumorigenesis and the seeds of metastases. Thus, my proposed objective was to explore relationship between these tissues expressed miRNAs and Cancer Stem Cells in breast cancer patients before and after chemotherapy. Methods: 39 Breast Cancer patients after pathological (biopsy) confirmation were enrolled in the present study. miRNA were extracted and converted into cDNA by using Exiqon kit (Germany) and then sybr green quantitative PCR were performed on CFX96 thermal cycler. CSCs (CD44+ with CD24-) were characterized by using CD44 and CD24 antibodies on BD flow cytometer. Results: The Breast cancer patients showed significant down-regulated expression of miR 21 (Mean Cq 22.50 ± 1.64 Vs 24.91 ± 1.95) expression after 3 cycle of standard chemotherapy out of four oncogenic MiRNA (mir-21 mir-17 mir-10a and 10b). The highest frequency of cells with expression of CD44- with CD24+ were observed and remain almost unchanged after 3 cycle of chemotherapy (Average percentage &Mean counts: 33.6 & 23953 Vs 32.6 and 21648) however CSC marker CD44+ withCD24- were significantly reduced after three cycle of chemotherapy ( Average percentage and Mean counts: 7.60 and 590 Vs 3.22 and 291). Conclusion: This study had shown the oncogenic miRNA like miR 21 and miR 10b have shown higher expression in breast cancer with higher mean count of CSCs (CD44+with CD24-) in fresh patient sample (who have not received any therapy). So this and similar type of study on larger sample size may help in guiding more precise treatment of chemotherapy with gene therapy in near future.