Protein Replacement Therapy with Cationic Lipid Assisted Intracellular Delivery
Altinoglu, Sarah.
2016
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Abstract: Protein therapeutics have unique advantages and challenges that set
this therapy apart from others. The delivery of proteins is regarded as a safe and direct
treatment approach with advantages such as high tolerances, low off target effects, and
potent efficacy. However, there are significant challenges in delivering protein past the
cell membrane where a substantial portion of thera... read morepeutic proteins require delivery.
Therefore, there remains a need for a vehicle capable of delivering protein intracellularly
while maintaining its integrity, structure, and function. Thus, the work presented herein
focused on expanding the cationic lipidoid delivery platform to encompass a broad range of
protein applications requiring intracellular delivery. An effective lipidoid for delivery
of recombinant PTEN protein was identified, characterized, and therapeutically evaluated
for intracellular replacement of PTEN in PTEN-null cancer cells. The lipidoid structure
EC16-80 demonstrated the most effective intracellular delivery compared to a range of
lipidoid structures and displayed an encapsulation efficiency of 80% complexed PTEN. The
interaction forces that contribute to the nanocomplexation were determined to be both
electrostatic and hydrophobic in nature, based on dissociation studies and thermotropic
measurements, respectively. The biological effects of delivering PTEN with EC16-80 resulted
in dose dependent cellular apoptosis and were confirmed to be the result of PTEN
antagonizing the AKT pathway, as displayed through western blot. Furthermore, the delivery
of PTEN protein predominantly affected PTEN deficient cells compared to cells with
wild-type PTEN. Together, these results highlight EC16-80/PTEN protein delivery as a
potential new therapeutic strategy selectively against PTEN deficient cancers.
Additionally, the effect of protein charge modification on PTEN was found to result in more
favorable particle characteristics (decrease in hydrodynamic radius and surface charge and
increase in % complexed PTEN) and delivery efficacy (decrease in IC50). Lastly, the
lipidoid EC16-80 also displayed intracellular delivery with both modified RNase-A protein
to inhibit lentivirus infection and with modified β-Glucocerebrosidase as protein
replacement therapy. Together, this work establishes a new treatment strategy for
PTEN-deficient cancers by directly delivering PTEN protein using lipidoid complexes.
Furthermore, the ability of EC16-80 to deliver various protein structures in multiple
disease models highlights the diverse utility in protein therapeutics.
Thesis (Ph.D.)--Tufts University, 2016.
Submitted to the Dept. of Biomedical Engineering.
Advisor: Qiaobing Xu.
Committee: David Kaplan, Hyunmin Yi, and Eric Park.
Keyword: Biomedical engineering.read less - ID:
- fx719z685
- Component ID:
- tufts:21168
- To Cite:
- DCA Citation Guide EndNote
