Exosomal linc-ROR mediates crosstalk between cancer cells and adipocytes to promote tumor growth in pancreatic cancer

Abstract

Exosomes are emerging as important mediators of the crosstalk between tumor cells and stromal cells in the microenvironment. However, the underlying molecular mechanism of pancreatic cancer (PC)-derived exosomes in the progression of the tumor microenvironment (TME) and crosstalk with adipocytes has not been elucidated. Exosomes isolated from PC cell culture supernatant through ultracentrifugation were rich in long intergenic non-coding ROR (linc-ROR). After constructing PC cell lines with stable linc-ROR knockdown or overexpression via the transfection of short hairpin RNA (shRNA) and pLent-U6-GFP-Puro, direct and indirect coculture systems were established to simulate the interaction between adipocytes and PC cells. Next, the effects of conditioned medium collected from dedifferentiated adipocytes on PC cell proliferation, motility, metastasis, and epithelial-mesenchymal transition (EMT) were evaluated by western blot analysis, colony forming, real-time cell analysis (RTCA), 5-ethynyl-2′-deoxyuridine (EdU), immunofluorescence (IF), Transwell, and wound-healing assays in vitro. Xenograft models were employed to identify whether conditioned medium loaded with interleukin-1β (IL-1β) promoted PC cell growth in vivo. Our results demonstrate that linc-ROR delivery via exosomes represents a brand-new perspective of dedifferentiating adipocytes in the TME of PC, which further induce PC cell EMT via the hypoxia inducible factor 1α (HIF1α)-ZEB1 axis. Moreover, exosomal linc-ROR may become a novel diagnostic marker for PC patients.