Exosomes released by cells can serve as vehicles for delivery of biological materials and signals. Long non-coding RNAs (lncRNAs) are non-coding RNAs longer than 200 nt, which roles are increasingly appreciated in various biological content. Tumor-derived exosomal lncRNAs have been implicated as signaling mediators to orchestrate cell function among neighbor tumor cells. However, the role of tumor-derived lncRNAs in cross-talk with environmental macrophages has yet to be explored. In this paper, we demonstrated that hepatocellular carcinoma (HCC) cells–derived exosomes contain elevated levels of lncRNA TUC339 and that HCC-derived exosomes could be taken up by THP-1 cells. In seeking to dissect the biological function of tumor secreting TUC339 in macrophages, we applied loss-of-function and gain-of-function strategies. We observed increased pro-inflammatory cytokine production, increased co-stimulatory molecule expression, and enhanced phagocytosis upon suppression of TUC339 by siRNA in THP-1 cells, and the opposite effect upon over-expression of this lncRNA, which indicates that TUC339 was involved in the regulation of macrophage activation. Moreover, we detected an elevated level of TUC339 in M(IL-4) macrophages as compared to M(IFN-γ + LPS) macrophages and a down-regulation of TUC339 expression during M(IL-4)-to-M(IFN-γ + LPS) repolarization and vice versa. Furthermore, suppression of TUC339 in macrophages diminished the expression of M(IL-4) markers upon IL-4 treatment while overexpression of TUC339 in macrophages enhanced M(IL-4) markers upon IFN-γ + LPS treatment, which suggests a critical function of TUC339 in the regulation of macrophage M1/M2 polarization. Lastly, using microarray analysis, we identified cytokine-cytokine receptor interaction, CXCR chemokine receptor binding, Toll-like receptor signaling, FcγR-mediated phagocytosis, regulation of the actin cytoskeleton, and cell proliferation are related with TUC339 function in macrophages. Our results provide evidence for a novel regulatory function of tumor-derived exosomal lncRNA TUC339 in environmental macrophages and shed light on the complicated interactions between tumor and immune cells through exosomal lncRNAs.

Currently, resistance to tyrosine kinase inhibitors, such as gefitinib, has become one major obstacle for improving the clinical outcome of patients with metastatic and advanced-stage non-small cell lung cancer (NSCLC). While cell behavior can be modulated by long non-coding RNAs (lncRNAs), the contributions of lncRNAs within extracellular vesicles (exosomes) are largely unknown. To this end, the involvement and regulatory functions of lncRNA H19 wrapped by exosomes during formation of gefitinib resistance in human NSCLC were investigated. Gefitinib-resistant cell lines were built by continuously grafting HCC827 and HCC4006 cells into gefitinib-contained culture medium. RT-qPCR assays indicated that H19 was increased in gefitinib-resistant cells when compared to sensitive parent cells. Functional experiments revealed that silencing of H19 potently promoted gefitinib-induced cell cytotoxicity. H19 was secreted by packaging into exosomes and this packaging process was specifically mediated by hnRNPA2B1. H19 wrapped in exosomes could be transferred to non-resistant cells, thus inducing gefitinib resistance. Moreover, treatment-sensitive cells with exosomes highly-expressing H19 induced gefitinib resistance, while knockdown of H19 abrogated this effect. In conclusion, H19 promoted gefitinib resistance of NSCLC cells by packaging into exosomes. Therefore, exosomal H19 may be a promising therapeutic target for EGFR+ NSCLC patients.

In guinea pigs, choroidal thickness (ChT) and choroidal blood perfusion (ChBP) simultaneously decrease in experimental myopia, and both increase during recovery. However, the causal relationship between ChBP and myopia requires further investigation. In this study, we examined the changes of ChBP with three different antimyopia treatments. We also actively increased ChBP to examine the direct effect on myopia development in guinea pigs. METHODS. Experiment 1: Guinea pigs wore occluders on the right eye for two weeks to induce form-deprivation myopia (FDM). Simultaneously they received daily antimyopia treatments: peribulbar injections of atropine or apomorphine or exposure to intense light. Experiment 2: The vasodilator prazosin was injected daily into the form-deprivation eyes to increase ChBP during the two-week induction of FDM. Other FDM animals received appropriate control treatments. Changes in refraction, axial length, ChBP, ChT, and hypoxia-labeled pimonidazole adducts in the sclera were measured. RESULTS. The antimyopia treatments atropine, apomorphine, and intense light all significantly inhibited myopia development and the decrease in ChBP. The treatments also reduced scleral hypoxia, as indicated by the decrease in hypoxic signals. Furthermore, actively increasing ChBP with prazosin inhibited the progression of myopia, as well as the increase in axial length and scleral hypoxia. CONCLUSIONS. Our data strongly indicate that increased ChBP attenuates scleral hypoxia, and thereby inhibits the development of myopia. Thus ChBP may be a promising target for myopia retardation. As such, it can serve as an immediate predictor of myopia development as well as a long-term marker of it.