Mesenchymal stem cell‐exosome‐mediated matrix metalloproteinase 1 participates in oral leukoplakia and carcinogenesis by inducing angiogenesis.

Background: In the malignant progression of oral leukoplakia (OLK) to oral squamous cell carcinoma (OSCC), the density of microvessels and expression of angiogenesis‐related molecules increases. Emerging evidence indicates that mesenchymal stem cells (MSCs) play an indispensable role in the tumor microenvironment. However, the role and mechanism of action of oral MSCs in inducing angiogenesis remain unclear. Therefore, it is necessary to explore the molecules and mechanisms that play a role in the tissue microenvironment. Methods: Exosomes were collected from normal oral mucosa (N‐Exo), OLK (OLK‐Exo), and OSCC (Ca‐Exo) MSCs, and their pro‐angiogenic capacity was evaluated in human umbilical vein endothelial cells (HUVECs) and a subcutaneously implanted tumor model in nude mice. Quantitative proteomics analysis was used to compare the exosome‐derived proteins between N‐Exo, OLK‐Exo, and Ca‐Exo. Results: Compared with that of the N‐Exo and control, OLK‐Exo and Ca‐Exo treatment significantly promoted HUVEC migration, invasion, and tube‐formation capability. In the nude mice model, immunofluorescence of CD31 showed that OLK‐Exo and Ca‐Exo substantially improved neovascularization around the grafts. Quantitative proteomics analysis revealed that matrix metalloproteinase 1 (MMP1) levels were significantly higher in the OLK‐Exo and Ca‐Exo groups than in the N‐Exo groups. Silencing MMP1 expression reversed the functional promoting effect of OLK‐Exo and Ca‐Exo on HUVECs. Conclusion: Exosomes from OLK‐MSCs and Ca‐MSCs have a stronger pro‐angiogenic ability through high MMP1 content. This new finding provides insight into the intervention with the secretion of MSC‐derived exosomes, which may be an innovative strategy for carcinogenesis. [ABSTRACT FROM AUTHOR]