PLK-1 Silencing in Bladder Cancer by siRNA Delivered with Exosomes

OBJECTIVE - To use exosomes as a vector to deliver siRNA to silence the polo-like kinase 1 gene (PLK-1) in bladder cancer cells.

METHODS - Exosomes were isolated from both human embryonic kidney 293 (HEK293) cell and mesenchymal stem cell (MSC) conditioned media.

Fluorescently labeled exosomes were co-cultured with bladder cancer and normal epithelial cells and uptake quantified by image cytometry. PLK-1 siRNA and negative control siRNA were loaded into HEK293 and MSC exosomes using electroporation. An invasive bladder cancer cell line (UMUC3) was co-cultured with the electroporated exosomes. Real-time PCR was performed. Protein analysis was performed by western blot. Annexin V staining and MTT assays were used to investigate effects on apoptosis and viability.

RESULTS - Bladder cancer cell lines internalize an increased percentage of HEK293 exosomes when compared to normal bladder epithelial cells. Treatment of UMUC3 cells with exosomes electroporated with PLK-1 siRNA achieved successful knockdown of PLK-1 mRNA and protein when compared to cells treated with negative control exosomes.

CONCLUSIONS - HEK293 and MSC exosomes were effectively used as a delivery vector to transport PLK-1 siRNA to bladder cancer cells in vitro resulting in selective gene silencing of PLK-1. The use of exosomes as a delivery vector for potential intravesical therapy is attractive.

Urology. 2016 Feb 11 [Epub ahead of print]

Kristin A Greco, Carrie A Franzen, Kimberly E Foreman, Robert C Flanigan, Paul C Kuo, Gopal N Gupta

Department of Urology, Loyola University Chicago, Maywood 60153, IL., Department of Urology, Loyola University Chicago, Maywood 60153, IL., Department of Pathology, Loyola University Chicago, Maywood 60153, IL; Oncology Institute, Loyola University Chicago, Maywood 60153, IL., Department of Urology, Loyola University Chicago, Maywood 60153, IL., Oncology Institute, Loyola University Chicago, Maywood 60153, IL; Department of Surgery, Loyola University Chicago, Maywood 60153, IL., Department of Urology, Loyola University Chicago, Maywood 60153, IL; Oncology Institute, Loyola University Chicago, Maywood 60153, IL; Department of Surgery, Loyola University Chicago, Maywood 60153, IL; Department of Radiology, Loyola University Chicago, Maywood 60153, IL.  

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