Abstract 1206: miR-205 replenishment in prostate cancer cells: A novel nanoparticle approach
Authors: Nagesh Prashanth K. , Chowdhury Pallabita , Boya Vijayakumar N. , Kashyap Vivek K. , Khan Sheema , Hafeez Bilal B. , Zafar Nadeem , Behrman Stephen W. , Chauhan Subhash C. , Jaggi Meena , Yallapu Murali M. 
Published: July 2017

Introduction

Prostate cancer (PrCa) is the most common male malignancy among men in the United States. Recent studies suggest that low expression of miR-205 is seen in PrCa cell lines and tumors in comparison to normal prostatic epithelial cells. A numer of studies have shown that restoration of miR-205 in PrCa cells resulted in supression of cell growth, epithelial-to-mesenchymal transition, and chemosensitization. However, due to the poor pharmacological kinetics and low in vivo stability of miR-205, serious limitations are being experienced at the clinical level. Therefore, we have chosen a novel nanoparticle-based approach to deliver miR-205, for improved therapeutic benefits in PrCa.

Methods

A novel miR-205 nanoparticle formulation (named miR-MPG) was generated which is composed of an iron oxide core layered with polyethylene imine (PEI), and NHS-PEG-NHS (PEG) polymer. The miR-205 withholding and release characteristic of miR-PEG were examined through fluorescence quenching and agarose gel electrophoresis. Hemocompatibility of this formulation was examined using a hemolysis assay. Cellular uptake of miR-MPG formulation was evaluated using flow cytometry and confocal studies. Further, therapeutic and chemosensitization activity of miR-205 were assessed using cell-culture based assays. Molecular effects associated with the PrCa cells growth inhibiton were evaluated through protein profiling and qRT-PCR analyses.

Results and Dissusion

miR-MPG formulation exhibited optimal particle size and zeta potential, which are suitable for cancer therapeutics. Agarose gel electrophoresis binding studies suggested 5 µg of nanoparticle formulation is optimum to hold 1 µg of miR-205 mimic. Release of miR-205 from miR-MPG was determined with respect to concentration of anionic molecules and in a time-dependent manner. We observed no hemolysis during miR-MPG interaction with the red blood cells indicating its hemocompatibility. In addition, miR-MPG particles exhibited superior internalization and endosmal escape in PrCa cells. This formulation displayed enhanced sensitization of PrCa cells to docetaxel. Additionally, it induced the expression of apoptotic proteins (Bax, Bim, cleaved PARP, and caspase 3), and downregulated the anti-apoptotic proteins (Bcl-2 and survivin). Moreover, the expression of the chemoresistance-associated proteins (PSMA and MDR1) was profoundly inhibited in cells treated with miR-MPG in the presence of docetaxel. Further dataset of qRT-PCR studies showed induced expression of the miR-205 and affected the expression of its downstream genes. These results suggest that miR-MPG formulation may serve as an ideal delivery vehicle to deliver miR-205.

Conclusion

Results from this study suggests that successful delivery of miR-205 through miR-MPG nanoparticles can induce sensitization potential for docetaxel treatment. This novel therapeutic modality might be effective for PrCa patients undergoing chemotherapy.

Citation Format: Prashanth K. Nagesh, Pallabita Chowdhury, Vijayakumar N. Boya, Vivek K. Kashyap, Sheema Khan, Bilal B. Hafeez, Nadeem Zafar, Stephen W. Behrman, Subhash C. Chauhan, Meena Jaggi, Murali M. Yallapu. miR-205 replenishment in prostate cancer cells: A novel nanoparticle approach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1206. doi:10.1158/1538-7445.AM2017-1206