Hessvik Nina Pettersen, Phuyal Santosh, Brech Andreas, Sandvig Kirsten, Llorente Alicia
Department of Biochemistry, The Norwegian Radium Hospital, Oslo, Norway.
Biochim Biophys Acta. 2012 Nov-Dec;1819(11-12):1154-63. doi: 10.1016/j.bbagrm.2012.08.016. Epub 2012 Sep 8.
Exosomes are small extracellular vesicles released to the extracellular milieu through fusion of multivesicular bodies with the plasma membrane. These vesicles contain microRNAs and might therefore be vehicles transferring genetic information between cells. The aim of this study was to investigate whether there was a sorting of microRNAs into exosomes in the prostate cancer cell line PC-3. In addition, microRNAs in PC-3 cells and in the non-cancerous prostate cell line RWPE-1 were compared. Exosomes were isolated from the conditioned media from PC-3 cells by ultracentrifugation and inspected by electron microscopy. Total RNA was isolated and microRNAs were analyzed by microarray analysis and real time RT-PCR. MicroRNA microarray analysis revealed that the microRNA profile of PC-3 released exosomes was similar to the profile of the corresponding parent cells. Nevertheless, a sorting of certain microRNAs into exosomes was observed, and low number microRNAs (microRNAs with a low number in their name) were found to be underrepresented in these vesicles. Moreover, the miRNA profile of PC-3 cells resembled the miRNA profile of RWPE-1 cells, though some miRNAs were found to be differently expressed in these cell lines. These results show that exosomes from PC-3 cells, in agreement with previous reports from other cell types, contain microRNAs. Furthermore, this study supports the idea that there is a sorting of microRNAs into exosomes and adds a new perspective by pointing at the underrepresentation of low number miRNAs in PC-3 released exosomes.
外泌体是通过多囊泡体与质膜融合释放到细胞外环境中的小细胞外囊泡。这些囊泡含有微小RNA，因此可能是细胞间传递遗传信息的载体。本研究的目的是调查在前列腺癌细胞系PC-3中是否存在微小RNA分选进入外泌体的情况。此外，还比较了PC-3细胞和非癌前列腺细胞系RWPE-1中的微小RNA。通过超速离心从PC-3细胞的条件培养基中分离出外泌体，并通过电子显微镜进行检查。分离总RNA，并通过微阵列分析和实时RT-PCR分析微小RNA。微小RNA微阵列分析显示，PC-3释放的外泌体的微小RNA谱与相应亲本细胞的谱相似。然而，观察到某些微小RNA分选进入外泌体，并且发现低编号微小RNA（名称中编号较低的微小RNA）在这些囊泡中含量不足。此外，PC-3细胞的miRNA谱与RWPE-1细胞的miRNA谱相似，尽管发现一些miRNA在这些细胞系中表达不同。这些结果表明，与其他细胞类型的先前报道一致，PC-3细胞的外泌体含有微小RNA。此外，本研究支持微小RNA分选进入外泌体的观点，并通过指出PC-3释放的外泌体中低编号miRNA含量不足增加了一个新的视角。
