Abstract. Exosomes are small membrane vesicles released by a variety of mammalian cells into the extracellular space and are involved in cell-to-cell signaling. This study aimed to investigate the effects of bladder cancer cell-derived exosomes on the regulation of tumor cell viability and apoptosis, as well as the underlying molecular events. Exosomes were purified from the supernatants of human bladder cancer T24 cell cultures. Transmission electron microscopy was used to confirm their morphology and western blot analyses determined the protein content of cells. Subsequently, bladder cancer cell lines were treated with different concentrations of exosomes. Tumor cell viability was shown to be reduced, as detected by the Cell Counting Kit-8 assay. Annexin V/flow cytometric assays showed that exosomes inhibited apoptosis of bladder cancer cell lines in a dose-and time-dependent manner. Exosomes were demonstrated to upregulate the expression of Bcl-2 and Cyclin D1 proteins, but reduce the levels of Bax and caspase-3 proteins in these cells. Moreover, exosomes dose-dependently increased the expression of phosphorylated Akt and extracellular signal-regulated protein kinase (ERK). In conclusion, this study demonstrated that bladder cancer cell-derived exosomes inhibited tumor cell apoptosis, which was associated with the activation of Akt and ERK pathway genes, suggesting that tumor-derived exosomes are involved in bladder cancer progression. Inhibition of exosome formation and release may therefore be a novel strategy in future treatment of bladder cancer.

Myeloid-derived suppressor cells (MDSCs), one of the main cell populations, are responsible for regulating the immune response, which accumulates in tumor-bearing mice and humans contributing to cancer development. Exosomes produced by tumor cells have been involved in tumor-associated immune suppression. However, the role of exosomes is unclear in the activation of MDSCs. Here, we have purified tumor-derived exosomes from the supernatants of Renca cell cultures. Transmission electron microscopy was used to confirm their morphology, and Western blot analysis showed that Hsp70 was rich in these isolated exosomes compared with the whole-cell lysates of Renca cells. Then, we demonstrated that there was a more powerful activity of exosomal Hsp70-mediated induction of proinflammation cytokines, tumor growth factors of MDSCs and tumor progression than exosomes pre-incubated with anti-Hsp70 antibody. Furthermore, we show that an interactive exosomal HSP70 and MDSCs determine the suppressive activity of the MDSCs via phosphorylation of Stat3 (p-Stat3). Finally, we show that exosomal Hsp70 triggers p-Stat3 in MDSCs in a TLR2-MyD88-dependent manner. Meanwhile, we also find that there is a more significant increase in the percentage of CD11b+Gr-1+ cells in the mice, which are treated with exosomal Hsp70 than that exosomes pre-incubated with anti-Hsp70 antibody. Hence, we believe that the signaling pathway activation by exosomal Hsp70 within MDSCs may be a significant target in future treatment of renal cell carcinoma.

No abstract

Natural killer cells are the key components in tumor immunity and defects in function are necessary for tumor immune escape. Emerging studies on tumor cell-derived exosomes have shown the biological significance in tumor microenvironment, but the underlying role of exosomes in regulating natural killer cells functions in clear cell renal cell carcinoma patients remains unknown. Firstly, we precisely characterized the phenotype and function of natural killer cells in clear cell renal cell carcinoma patients vs healthy controls. With an inhibitory phenotype, tumor-infiltrating natural killer cells exhibited poor cytotoxic capacity and deficient potential to produce cytokines compared with natural killer cells from tumor margin tissue and non-tumor tissue. Next, we revealed that primary tumor cells trigged natural killer cell dysfunction in an exosome-dependent manner. Interestingly, exosomes from primary tumor cells were preferentially enriched with TGF-β1 which acted as important mediator of natural killer cell functional deficiency. In vitro culture of exosomes induced natural killer cell dysfunction mediated by activation of the TGF-β/SMAD signaling pathway, and abrogated by knockdown TGF-β. Our data indicate that exosomes from clear cell renal cell carcinoma induce natural killer cells dysfunction by regulating the TGF-β/SMAD pathway to evade innate immune surveillance.

Abstract.The aims of the current study were to determine whether 786-0 renal cancer cell-derived exosomes promote human umbilical vein endothelial cells (HUVECs) to form tubular structures and to uncover the underlying mechanisms associated with this process. Exosomes were extracted and purified using ultrafiltration and sucrose gradient centrifugation and characterized by transmission electron microscopy. Tubular structure formation was observed using the matrigel tubular assay. In addition, an adenovirus vector was used to transfect the hepatocyte cell adhesion molecule (hepaCAM) gene into renal cancer 786-0 cells. The expression of hepaCAM and vascular endothelial growth factor (VEGF) mRNA and protein was determined by reverse transcription-polymerase chain reaction and western blot analysis, respectively. Tumor cell-derived exosomes were observed to significantly increase tubular formation in HUVECs. Following transfection with the hepaCAM gene, VEGF expression in 786-0 cells was markedly decreased. In HUVECs, exosome treatment increased VEGF mRNA and protein expression, while hepaCAM expression was only decreased at the protein level. In the present study, renal cancer 786-0 cell-derived exosomes significantly promoted angiogenesis via upregulation of VEGF expression in HUVECs, which may be induced by the downregulation of hepaCAM.

No abstract

Our study shows that a 6-month course of tamsulosin ameliorated symptoms of CP/CPPS during treatment. However, these effects decreased gradually 6 months after cessation of treatment. This suggests that long-term tamsulosin may be indicated, particularly in the responders.

This study aimed to evaluate the effects of miR-93 on the growth and invasiveness of prostate cancer (PC) cells (PCCs). Real-time PCR was carried out to detect the expression of miR-93 in the PC tissues and cell lines. The adjacent normal tissues served as controls. For in vitro experiments, methyl thiazolyl tetrazolium, clone formation, tumor cell invasion assays, and western blot analysis (WBA) were performed to confirm the variations in the proliferation and invasiveness of PCCs, prior and subsequent to transfection with an miR-93 antisense oligonucleotide (ASO), which blocks miR-93 binding to its target. Furthermore, the effect of miR-93 on the proliferation of PCCs was examined. Finally, the expression levels of the target genes of miR-93 were determined by WBA. miR-93 expression was higher in PC tissues than in the adjacent normal tissues, and a reduction in the miR-93 level remarkably inhibited the proliferation and invasiveness of PCCs. Moreover, miR-93 enhanced the expression of its target genes TGFΒR2, ITGB8, and LATS2. The results of this study suggest that miR-93 may promote the proliferation and invasion of PCCs by upregulating its target genes TGFBR2, ITGB8, and LATS2.