Figure 3.

MSC-Exos play different roles in the tumor microenvironment by carrying different biological factors. MSC-Exos recruited in the OSCC tumor microenvironment promotes tumor growth by increasing MMP1 levels and promoting HUVEC migration, invasion, and tube formation capabilities. Genetically engineered MSC-Exos with high expression levels of CXC chemokine receptor type 4 (CXCR 4) specifically bind to stromal cell-derived factor 1 (SDF-1) on the tumor surface. The Exos efficiently accumulate at tumor sites and release their small interfering RNA (siRNA) into the tumor cells, knocking down the Survivin gene in tumor cells to inhibit tumor growth.