Figure 4.

Blocking exosome transmission decreased tumor development

(A) After injection with B16 cells, C57 mice were intraperitoneally injected with exosomes. Injection with circSKA3 exosomes decreased mouse survival significantly, which could be prevented by the delivery of RNAse A, Digoxin, or MβCD (n = 10). (B) circSKA3 levels decreased when mice were injected with RNAse A (left). Total RNA levels in the exosomes decreased when mice were injected with RNAse A, Digoxin, or MβCD (middle). Total exosome levels decreased when mice were injected with Digoxin or MβCD (right) (n = 6). (C) Left, real-time PCR measurement of the tumor tissues showed that injection with circSKA3-containing exosomes increased the circSKA3 levels in tumor tissues, which could be blocked by injection with RNAse A, Digoxin, or MβCD. Right, in situ hybridization staining was performed in tumor sections followed by quantitation. Injection with circSKA3-containing exosomes increased circSKA3 uptake in the tumors, which was prevented by the application of RNAse A, Digoxin, or MβCD (n = 6). (D) Ascites, floating cells, and tumors from mice injected with circSKA3-transfected B16 cells or MB-231 cells were analyzed for circSKA3 levels. circSKA3 was detected at the highest level in ascites (left), while SKA3 mRNA was mainly detected in the tumors (right) (n = 6), ∗ p<0.05; ∗∗ p<0.01; Error bars, SD.