bm5b01189_si_001.pdf (354.96 kB)
Download fileFolate Receptor Targeted Delivery of siRNA and Paclitaxel to Ovarian Cancer Cells via Folate Conjugated Triblock Copolymer to Overcome TLR4 Driven Chemotherapy Resistance
journal contribution
posted on 11.01.2016, 00:00 authored by Steven
K. Jones, Vincent Lizzio, Olivia M. MerkelThis paper focuses on the ability
of a folate-decorated triblock
copolymer to deliver a targeted dose of siRNA in order to overcome
chemotherapy resistance which can commonly cause complications in
ovarian cancer patients. The micelleplexes that are formed upon electrostatic
interaction with siRNA are used to deliver siRNA in a targeted manner
to SKOV-3 ovarian cancer cells that overexpress folate receptor-α
(FRα). The triblock copolymer consists of polyethylenimine-graft-polycaprolactone-block-poly(ethylene
glycol) (PEI-g-PCL-b-PEG-Fol). In
this work, polymers of different molecular weights of PEG, as well
as different grafting degrees of the (g-PCL-b-PEG-Fol)
chains to PEI, were analyzed to optimize targeted siRNA delivery.
The polymers, their micelleplexes, and the in vitro performance of
the latter were characterized by nuclear magnetic resonance, dynamic
light scattering, transmission electron microscopy, flow cytrometry,
western blot, confocal microscopy, and in luciferase assays. The different
PEI-g-PCL-b-PEG-Fol conjugates showed
suitable sizes below 260 nm, especially at N/P 5, which also allowed
for full siRNA condensation. Furthermore, flow cytometry and Western
blot analysis demonstrated that our best polymer was able to effectively
deliver siRNA and that siRNA delivery resulted in efficient protein
knockdown of toll-like receptor 4 (TLR4). Consequently, TLR4 knock
down within SKOV-3 cells resensitized them toward paclitaxel (PTX)
treatment, and apoptotic events increased. This study demonstrates
that PEI-g-PCL-b-PEG-Fol conjugates
are a reliable delivery system for siRNA and are able to mediate therapeutic
protein knockdown within ovarian cancer cells. Additionally, this
study provides further evidence to link TLR4 levels to chemotherapy
resistance.