In what marked the first-ever synthesis of a nanoparticle-aptamer bioconjugate, the nanoparticles were conjugated to RNA aptamers that bind to the prostate specific membrane antigen (PSMA) ?a well known marker for prostate cancer which is over-expressed on certain prostate epithelial cells. Experimental results described at ECCO 13 show that these bioconjugates successfully and selectively adhered to PSMA-positive prostate cancer cells, while PSMA-negative cells were not targeted. This prostate cancer targeting was modeled using a microfluidic device and shown to occur under physiological fluid flow conditions that are present in systemic microvasculature, making their use after intravenous administration therapeutically relevant. The investigators also used high magnification microscopy and 3-D image reconstruction to study the localisation of the bioconjugates after incubation with the prostate cancer cells and confirmed that the particles were rapidly internalised into the targeted cells ?an important fact since the payload of nanoparticles may be released inside the cancer cells in a regulated manner over an extended period of time.
The study principle investigator Dr Omid Farokhzad from Harvard Medical School, USA, commented, "Our tumour reduction data in mice using bioconjugates which have the chemotherapeutic agent, docetaxel, encapsulated within the nanoparticles are remarkably promising. In close collaboration with Dr. Robert Langer at MIT, we are continuing to test and optimise our vehicles in larger animal models of prostate cancer with the goal of one day using them on patients with hormone refractory prostate cancer where the current the
Source:University of Pittsburgh Medical Center