CircESR1 and HNRNPAB function in estrogen receptor positive (ER+) breast cancer [RNA-Seq]

Breast cancer (BC) is the most prevailing type of cancer among women in the world. ERa protein, which is transcribed and translated by estrogen receptor gene ESR1, is one of the marker molecules for clinical classification of BC. However, whether circRNAs specifically expressed in hormone receptor-positive BC play a role which is independent of ERa (estrogen receptor alpha) protein activity and signaling pathways is unknown. Whether these circRNAs could impinge on the sensitivity of ER+ BC cells to the endocrine therapy and targeted drug therapy is also unexplored.By screening circRNAs involved in estrogen receptor (ER) signaling, circESR1 was identified as a circRNA exhibiting high specificity of expression in ER+ breast cancer. Our studies elucidate a novel signaling complex centering around circESR1 and HNRNPAB in ER+ breast cancer and suggest that circESR1 might represent a potential therapeutic target for this disease. Overall design: Unbiased transcriptome sequencing (bulk RNA-seq) was performed to have identified differentially expressed genes (DEGs) due to circESR1 or HNRNPAB depletion in MCF-7 cells. In details, MCF-7 cells were infected circESR1 or HNRNPAB shRNAs with lentivirus. Then the RNA was isolated. Total RNA sample was extracted and quantified with OD 260/280 ratio > 1.8 and OD 230/260 ratio > 2 were sent to BGI Genomics (Shenzhen, China) for sequencing.