Abstract: Objective:To study the changes of long non-coding RNA (lncRNA) and messenger RNA (mRNA) expression profiles in paclitaxel-induced breast cancer MCF-7 resistant cells (MCF-7/PR),and to screen the key lncRNAs that regulate the drug resistance of breast cancer cells to paclitaxel,providing theoretical basis for the molecular target of reversing paclitaxel resistance.Methods:The expression profiles of lncRNAs and mRNAs in MCF-7/PR cells were detected by ArraystarlncRNA microarray.Differentially expressed lncRNAs and mRNAs were selected using Agilent GeneSpring GX v12.1 software,and GO and KEGG pathways were analyzed for differential mRNAs to find biological pathway involved in mRNAs Simultaneous analysis of lncRNAs and corresponding mRNAs was performed to speculate the function of lncRNAs.Results:A total of 1 504 lncRNAs and 2 264 mRNAs were differentially expressed in MCF-7/PR cells compared with MCF-7 parental cells(Fold change >2.0).GO clustering analysis showed that up-regulated mRNAs and down-regulated mRNAs were involved in many different biological processes.Further analysis revealed that differential lncRNAs might exert their biological functions by affecting the corresponding mRNAs.Conclusions:This study finds that the expression of lncRNAs and mRNAs in paclitaxel-resistant cells of breast cancer is different.Differentially expressed genes can provide clues for finding new sensitive targets or biomarkers for chemotherapy.