KRAS-dependent sorting of miRNA to exosomes

Abstract

Mutant KRAS colorectal cancer (CRC) cells release protein-laden exosomes that can alter the tumor microenvironment. To test whether exosomal RNAs also contribute to changes in gene expression in recipient cells, and whether mutant KRAS might regulate the composition of secreted microRNAs (miRNAs), we compared small RNAs of cells and matched exosomes from isogenic CRC cell lines differing only in KRAS status. We show that exosomal profiles are distinct from cellular profiles, and mutant exosomes cluster separately from wild-type KRAS exosomes. miR-10b was selectively increased in wild-type exosomes, while miR-100 was increased in mutant exosomes. Neutral sphingomyelinase inhibition caused accumulation of miR-100 only in mutant cells, suggesting KRAS-dependent miRNA export. In Transwell co-culture experiments, mutant donor cells conferred miR-100-mediated target repression in wild-type-recipient cells. These findings suggest that extracellular miRNAs can function in target cells and uncover a potential new mode of action for mutant KRAS in CRC.DOI: http://dx.doi.org/10.7554/eLife.07197.001

Therapeutic and diagnostic applications of extracellular vesicles

“…However, these sequences could not be retrieved in miRNAs accumulating in colorectal cancerderived EVs, implying the existence of distinct sorting pathways [159]. Although progress is being made, in general these sorting mechanisms remain vaguely defined to date.…”

Extracellular microRNAs as messengers in the central and peripheral nervous system

“…The increased stability of extracellular microRNAs is due to the fact that they are protected from degradation by being packaged into extracellular vesicles (EVs) [9,31,32,[36][37][38][39][42][43][44][45] or bound to proteins [46][47][48][49][50] (Figure 1). A variety of different vesicles are actively secreted from cells.…”

“…A variety of different vesicles are actively secreted from cells. MicroRNAs have been detected in exosomes [9,31,[36][37][38][39][42][43][44], shedding vesicles [32] and large dense-core vesicles (LDCVs) [45]. Proteins that have been found associated with…”

“…Due to its known role in neurons, this protein may be of particular importance for microRNA export in the nervous system. Other proteins that have been implicated in the recruitment of microRNAs into EVs or in the selective export of microRNAs are oncogene KRAS [42], membrane-binding protein Annexin A2 [79], transcription factor KLF2 [80] and Rab family proteins [80]. However, their exact mechanisms are unknown.…”

Analysis of a Mirna Set (Mir-21, -181a, and -146a) as a Method of Differential Diagnosis of Thyroid Nodules

“…С другой стороны, полученные данные не позволяют исключить возмож-ность того, что другие ткани могут секретировать в кро-воток экзосомы, содержащие «маркерные» миРНК, вне зависимости от наличия или отсутствия опухоле-вого процесса. Кроме того, в нескольких экспери-ментальных исследованиях было показано наличие ме ханизма внутриклеточной «сортировки» миРНК в процессе формирования экзосом и доказана разница между профилем миРНК внутри клетки и в экзосомах, секретируемых клеткой [22]. В целом, этот вопрос имеет скорее фундаментальное, а не прикладное зна-чение, т. к. для практического использования миРНК в качестве онкомаркера важна связь между наличием опухоли и уровнем миРНК в сыворотке, даже если ис-точником миРНК является неопухолевая ткань.…”