Discipline: Biological Sciences
Subcategory: Cancer Research
George Olverson IV - Xavier University of Louisiana
Co-Author(s): G Olverson1; S Chaudhry1; S Chandra1; N Hall1; K Wiltz1; R Evans1; T Mandal2; S Dash3 and A Kundu1; S Muniruzzaman
Hypothesis: The MDR (multi-drug resistance) of metastatic breast cancer cells is accompanied with the overexpression of P-gp transporter. This study has been focused to determine whether silencing the expression of P-gp by aptamer-labeled siRNA nanoparticles could enhance the delivery of doxorubicin into breast cancer cells in culture.
DESIGN METHODS: Nanoparticles containing siRNA have been developed in the RCMI Nanotechnology Core at Xavier University. For targeted delivery of the particles, Aptamer A6 has been used which can bind to Her-2 receptors on breast cancer cells. The cytotoxicity of the particles has been assessed on different breast cancer cells. The expression and targeted knockdown of P-gp have been assessed by western blotting and immunofluorescence analysis. The doxorubicin accumulation into the cells has also been observed before and after the knockdown of P-gp by immunofluorescence and FACS analysis.
RESULTS: This study has shown that the uptake of Dox by Dox-resistant 4T1-R is significantly less than Dox-sensitive 4T1-S which is partly attributed to the higher expression of drug-efflux pump P-gp on the surface of the resistant cells. The targeted knockdown of P-gp has been enhanced when the particles carrying P-gp siRNA was labeled with aptamer. Concurrently, the uptake of Dox into the Dox-resistant 4T1-R breast cancer cells has increased significantly when the P-gp was silenced by P-gp siRNA-encapsulated aptamer-labeled nanoparticles.
CONCLUSIONS: This preliminary study concludes that downregulating P-gp expression by targeted delivery of P-gp siRNA using aptamer-labeled lipid based hybrid nanoparticles could effectively increase the intracellular trafficking of doxorubicin in Dox-resistant mouse breast cancer cells.
Funder Acknowledgement(s): This work is funded in part by the Louisiana Cancer Research Consortium, NIMHD grant number TL4GM118968 and T34GM007716, NIGMS grant number UL1GM118967 and R25GM060926, CUR from Xavier University of Louisiana, LBRN Pilot and Full grant, and NSF
Faculty Advisor: Dr. Anup Kundu, email@example.com
Role: Formulated Nanoparticles, FACS analysis, Cell culturing, Treatment of chemotherapeutic Agents.