Category: Preclinical Development
Purpose: Emerging evidence shows that exosomes transfer proteins and nucleic acids to and from prostate cancer (PCa) cells. The transfer of cargo proteins via exosomes can induce phenotypic changes in recipient cells and promote pre-metastatic niche. Integrin Subunit Alpha 2 (ITGA2) mediates metastasis through modulation of MMPs via enhanced activation of the FAK/Src/paxillin/Rac/JNK signaling pathway. We aimed to delineate the role of exosomal ITGA2 derived from metastatic PCa cells in inducing localized PCa cells to acquire aggressive phenotypes.
Methods: Exosomes were collected from conditioned media of PCa cells by differential ultracentrifugation and characterized by TEM, Zeta potential and Western blot analyses. Proteomic analysis of PCa-derived exosome was performed and results were validated by Western blot analysis. Functional role of exosomal ITGA2 in mediating PCa aggressiveness was assessed by cell proliferation, migration and invasion assays. Immunostaining was carried out to examine whether ITGA2 correlates with aggressive forms in PCa patients.
Results: The size of exosomes was confirmed by TEM, Zeta potential and expression of exosomal protein markers CD81 and CD9. Proteomic analysis showed that ITGA2 was one of top proteins that were highly packaged in exosome derived from PCa cells. ITGA2 was highly expressed in exosomes of metastatic versus non-metastatic cells. A significant increase (p< 0.01) in migration and invasion was observed after ITGA2 overexpression in E006AA cells. However, there is no significant difference in cell proliferation of these cells. Co-culture of exosomes derived from DU-145 with E006AA cells resulted in significant changes (P< 0.01) in cell proliferation, migration and invasion. ITGA2 expression was higher (P< 0.001) in metastatic versus localized tissue specimens.
Conclusion: Our findings underline the role exosomal protein in altering the phenotype of localized PCa into more aggressive metastatic cells via the transfer of exosomal-associated ITGA2. Expression of ITGA2 was correlated with poor clinical outcome in PCa patients.
Rofaida Gaballa– Kingsville, Texas
Mohamed Mahmoud– Kingsville, Texas
Hamdy Ali– kingsville, Texas
Mohamed Gaballah– Kingsville, Texas
Tamer Fandy– Associate Professor, University of charleston, school of Pharmacy, Charleston, West Virginia
Hamed Ali– Kingsville, Texas
Heba Salem– Kingsville, Texas
Mohamed Kandeil– Kingsville, Texas
Zakaria Abd Elmageed– kingsville, Texas