Background Tumor-associated macrophages are considered to be a major contributor affecting the development of tumors. Recently, numerous studies have shown that tumor cells were able to educate their microenvironment by delivering a significant amount of exosomes, however, the mechanism that exosomes from PCa cells work in macrophage polarization remains obscure. Therefore, we sought to determine whether blockade of exosome generation by GW4869, an inhibitor of exosome biogenesis, would impede macrophages from differentiating into M2 cells. Results In this study, we first obtained exosomes from the supernatant media of PCa cells cultured with exosome-free serum using the Magcapture™ Exosome Isolation Kit PS, and then investigated their effects on macrophages. Our data confirmed that exosomes released by prostate cancer cells can induce macrophages to differentiate into M2 cells. Mechanistically speaking, exosomes exert their effects on macrophages through activating the AKT and STAT3 signaling pathways. Importantly, treatment with GW4869 significantly inhibited the release of exosomes from PCa cells, and further impaired M2 differentiation of macrophages and their pro-tumor activity. We also demonstrated that GW4869 was able to inhibit the education of M2 macrophages, and then inhibit the progression of prostate cancer in vivo. Conclusions In brief, our findings indicated that GW4869 impeded the PCa exosome-induced M2 differentiation of macrophages and the progression of prostate cancer, suggesting that GW4869 could play an important role in the treatment of prostate cancer metastasis as an inhibitor of tumor exosome secretion.

In this study, we aim to investigate retinal thickness (RT) and superficial vascular density (SVD) differences between patients with systemic sclerosis (SSc) and healthy controls (HCs) by optical coherence tomography angiography (OCTA). Sixteen patients with a definitive SSc diagnosis without clinical signs of retinopathy and 16 normal control subjects were recruited. All individuals underwent OCTA scanning to assess macular RT and SVD. We divided each image into nine subregions as the early treatment diabetic retinopathy study (ETDRS). Visual acuity (VA) was considerably different between patients with SSc (32 eyes) and control subjects (32 eyes) ( p < 0.001 ). Compared to the control group, individuals with SSc had decreased inner RT in inner superior, outer superior, outer temporal, inner temporal, center, and inner nasal regions ( p < 0.05 ). Outer RT was decreased in the outer and inner temporal regions, and full RT was decreased in the regions of outer superior, inner superior, inner temporal, and outer temporal, in comparison to the control group ( p < 0.05 ). Patients with SSc had significant reduction of SVD in the inner and outer of both superior and temporal, besides outer nasal regions than controls. ( p < 0.05 ). Moreover, SVD was significantly associated with the outer temporal region of patients suffering from SSc ( p < 0.05 ). Diagnostic Sensitivity of RT and SVD of Inner Superior Regions in SSc, as indicated by areas under curves of the Receiver Operating Characteristic (ROC), were 0.874 (95% CI: 0.786–0.962) and 0.827 (95% CI: 0.704–0.950), respectively. In conclusion, VA may be affected by RT variations inside the macula in patients with SSc. Measuring RT with OCTA could be a useful predictor of early diagnosis.