Department of Biological Sciences, Vanderbilt University Medical Center, Nashville, United States; Vanderbilt University, Nashville, United States
Jeffrey L Franklin
Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, United States; Department of Medicine, Vanderbilt University Medical Center, Nashville, United States; Affairs Medical Center, Nashville, United States
Yongchao Dou
Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, United States
Qi Liu
Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, United States
James N Higginbotham
Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, United States; Department of Medicine, Vanderbilt University Medical Center, Nashville, United States
Michelle Demory Beckler
Department of Medicine, Vanderbilt University Medical Center, Nashville, United States
Alissa M Weaver
Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, United States; Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, United States; Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, United States
Kasey Vickers
Department of Cardiology, Vanderbilt University Medical Center, Nashville, United States
Nirpesh Prasad
HudsonAlpha Institute for Biotechnology, Huntsville, United States
Shawn Levy
HudsonAlpha Institute for Biotechnology, Huntsville, United States
Bing Zhang
Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, United States
Robert J Coffey
Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, United States; Department of Medicine, Vanderbilt University Medical Center, Nashville, United States; Affairs Medical Center, Nashville, United States
James G Patton
Department of Biological Sciences, Vanderbilt University Medical Center, Nashville, United States; Vanderbilt University, Nashville, United States
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.
