http://www.ncbi.nlm.nih.gov/pmc/article ... -19707.pdf
Targeted destruction of HIV-positive cells
Sharma, Jyoti R; Dodgen, Cleo1; Skepu, Amanda and Meyer, Mervin
Biotechnology, University of Western Cape, Bellville, Cape Town, South Africa. Nanotechnology Innovation Centre, Mintek, Randburg, South Africa.
Introduction: HIV/AIDS is now a global epidemic that has become the leading infectious killer of adults worldwide. Although
antiretroviral (ARV) therapy has dramatically improved the quality of life and increased the life expectancy of those infected with
HIV but frequency of dosing and drug toxicity as well as the development of viral resistance pose additional limitations.
The rapidly expanding field of nanotechnology has vast potential to radically advance the treatment and prevention of HIV/
AIDS. Nanoparticles can provide improved drug delivery, by virtue of their small size, robustness, safety, multimodality or
multifunctionality.
Aims and objectives: Since HIV primarily infects CD4 cells; we aim to use CD4 as a selectable target to deliver a pro-apoptotic
protein to HIV-infected cells using nanoparticles as carriers. The aim of study was to develop a nanotechnology-based death
inducing delivery system for the destruction of CD4HIV infected cells through the activation of caspase-3.
Methodology: A modified caspase-3 protein (Mut-3) was engineered, which is cleavable only by HIV-1 protease. Mut-3 can
activate apoptosis in the presence of HIV-1 protease, consequently killing HIV-positive cells. Mut-3 protein was conjugated to
gold nanoparticles together with a CD4-targeting peptide. The efficacy of the gold nanoparticles was tested on CHO cells that
were genetically engineered to express GFP labelled CD4 and HIV-1 protease.
Results: Mut-3 was expressed in bacterial cells and purified. CHO cells that stably over express CD4-GFP and HIV-1 protease were
selected using Fluorescence Activated Cell Sorting. Dose response cell culture experiments showed that gold nanoparticles
without Mut-3 and CD4-targeting peptide did not induce cell death in CHO cells, while gold nanoparticles that was conjugated
with Mut-3 and the CD4-targeting peptide rapidly induced cell death in CHO cells.
Conclusions: Our results suggest that gold nanoparticles conjugated with Mut-3 and a CD4-targeting peptide could potentially
induce apoptosis in HIV-infected cells.