Identification of differentially expressed miRNAs of exosome-like microvesicles secreted from mouse colon cancer stem cells
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ABSTRACT: As accumulating evidence suggests cancer cells exhibit stem-like properties for advanced diseases and cancer stem cells (CSCs) have been identified in various tumor types, revisiting present knowledge toward CSCs is essential. The identification of exosome-loaded miRNAs responsible for stemness and chemoradioresistance of CSCs should eventually leadd to development of novel therapeutic approaches.
Project description:As accumulating evidence suggests cancer cells exhibit stem-like properties for advanced diseases and cancer stem cells (CSCs) have been identified in various tumor types, revisiting present knowledge toward CSCs is essential. The identification of exosome-loaded miRNAs responsible for stemness and chemoradioresistance of CSCs should eventually leadd to development of novel therapeutic approaches.
Project description:Here, we developed an in situ labeling approach to identify exosome-loaded proteins, which bypasses the traditional exosome isolation steps. In this method, an engineered ascorbate peroxidase targeting to endosomes-destined exosomes was used to label proteins loaded inside exosomes released from kidney proximal tubule-derived cells. Mass spectrometry analysis of the kidney proximal tubule-derived cells identified oxidative stress-induced exosome proteome alteration.
Project description:The exosome functions in the degradation of diverse RNA species, yet how it is negatively regulated remains largely unknown. Here, we show that NRDE2 forms a 1:1 complex with MTR4, a nuclear exosome cofactor critical for exosome recruitment, via a conserved MTR4-interacting domain (MID). Unexpectedly, NRDE2 mainly localizes in nuclear speckles, where it inhibits MTR4 recruitment and RNA degradation, and thereby ensures efficient mRNA nuclear export. Structural and biochemical data revealed that NRDE2 interacts with MTR4's key residues, locks MTR4 in a closed conformation, and inhibits MTR4 interaction with the exosome as well as proteins important for MTR4 recruitment, such as the cap-binding complex (CBC) and ZFC3H1. Functionally, MID deletion results in the loss of self-renewal of mouse embryonic stem cells. Together, our data pinpoint NRDE2 as a nuclear exosome negative regulator that ensures mRNA stability and nuclear export.
Project description:Saliva is a useful biofluid for the early detection of disease, but how distal tumors communicate with the oral cavity and create disease-specific salivary biomarkers remains unclear. Using an in vitro breast cancer model, we demonstrated that breast cancer-derived exosome-like microvesicles are capable of interacting with salivary gland cells, altering the composition of their secreted exosome-like microvesicles. We found that the salivary gland cells secreted exosome-like microvesicles encapsulating both protein and mRNA. We also showed that the interaction with breast cancer-derived exosome-like microvesicles communicated and activated the transcriptional machinery of the salivary gland cells. Thus, the interaction altered the composition of the salivary gland cell-derived exosome-like microvesicles on both the transcriptomically and proteomically.