The roles of miR-193a in tumor exosomes

 
Oct 16, 2017 1:00 PM–2:00 PM (EDT)
Duration: 1hrs

Cancer cell extracellular microvesicles (EVs) are thought to promote cancer progression through cell-cell communication, however, whether exosome release also has a biological effect on the exosome donor cell is poorly defined. In this webinar, we present data generated from three colon cancer models (mouse CT26 colon tumor model, CT26 liver metastasis model, and human SW620 colon tumor model) and from colon cancer patients, to address this question. We present evidence that colon tumor cells selectively sort tumor suppressor miRNA into tumor exosomes, leading to promotion of tumor progression without pressure. One specific exosomal miRNA, miR193a, was shown to target the 3’UTR of mRNA encoding for caprin1, upregulating Ccnd2 and c-myc, and ultimately causing cell cycle G1 arrest and cell proliferation repression. As a result, miR193a could serve as an excellent potential biomarker candidate for prognosis of colon cancer progression.


To summarize, we define a new role for exosomes that allows donor tumor cells to grow under no pressure by oncoprotein-dependent sorting of tumor suppressor miRNA out of tumor cells. This finding provides a solid foundation for further investigation of whether intracellular machinery regulates tumor suppression versus oncogenic miRNA sorting in/out of exosomes. This approach may thus provide new therapeutic strategies for the treatment and/or prevention of cancer due to dysregulation of cellular miRNA homeostasis.


Huang-Ge Zhang, Ph.D.