Gene expression profiling study by RNA-seq for identifying gene signatures associated with castration-refractory prostate cancer (CRPC) development.

The objective of this study is to identify gene signature associated with castration-refractory prostate cancer (CRPC) development. We carried out RNA-seq based transcriptome profiling using 45 prostate samples with various disease progression steps such as benign prostate hyperplasia (BPH), primary cancer of prostate (CaP), advanced CaP and CRPC. Via various statistical analyses, we identified significant gene set associated with each progression step and observed that AR was the only gene feature associated with all progression steps, indicating that AR is the crucial mediator of and has a diverse activity across the CaP progressions. Among the samples in this data set, there are 4 pairs of advanced CaP and CRPC samples, in which each pair was obtained from the same patient. Using these paired samples, we also determined differentially expressed genes between advanced CaP and CRPC, and performed comparative analysis of significant gene lists in matched sample pairs and in unpaired remained samples. By assessing expression difference between advanced CaP and CRPC groups, 309 and 182 genes were statistically significant in paired and unpaired samples, respectively (P < 0.001). When these two gene lists were compared, a total of 15 genes were common and applied to a number of downstream experimental assays. Overall design: RNA-seq data of 45 CRPC samples were generated. Total RNA was isolated by RNeasy Mini Kit (Qiagen, CA, USA), according to the manufacturer''s protocol. The quality and integrity of the RNA were confirmed by agarose gel electrophoresis and ethidium bromide staining, followed by visual examination under ultraviolet light. Sequencing library was prepared using TruSeq RNA Sample Preparation kit v2 (Illumina, CA, USA) according to the manufacturer's protocols. Briefly, mRNA was purified from total RNA using poly-T oligo-attached magnetic beads, fragmented, and converted into cDNAs. Then, adapters were ligated and the fragments were amplified on a PCR. Sequencing was performed in paired end reads (2x100 bp) using Hiseq-2000 (Illumina).

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Yun SJ, Kim SK, Kim J, Cha EJ, Kim JS, Kim SJ, Ha YS, Kim YH, Jeong P, Kang HW, Kim JH, Park JL, Choi YK, Moon SK, Choi YH, Kim SY, Kim WJ