The researchers have gone onto demonstrate that injecting the virus particles alongside chemotherapy drugs, instead of the more common approach of packing the drugs inside a particle, could provide an even more potent benefit. The aim is to test out the delivery system on people once further animal trials have been completed. The new development is a collaborative effort between Case Western Reserve University School of Medicine, Dartmouth Geisel School of Medicine and RWTH Aachen University (Germany).
The international group of scientists have discovered that potato virus particles can be injected into melanoma tumor sites to activate an anti-tumor immune system response. The study also established that by injecting the nanoscale plant virus particles together with an chemotherapy drug into tumor sites at the same time leads to even greater suppression of the tumor. To slow down the progression in mice the anti-cancer drug doxorubicin was used. Doxorubicin, sold under the trade name Adriamycin, is a chemotherapy medication used to treat cancer. This includes breast cancer, bladder cancer, Kaposi’s sarcoma, lymphoma, and acute lymphocytic leukemia.
The researchers also found that when they injected combination nanoparticles, a situation when the the chemotherapy medicine is physically attached to the virus particles, there was no additional benefit. This meant that “vaccinating” mice with potato virus nanoparticles directly at a cancer site is the optimal approach to achieve an anti-tumor response.
Commenting on this, lead researcher Professor George J. Picha (of the Case Western Reserve School of Medicine) said: ““It’s attractive to want to create multifunctional nanoparticles that can ‘do it all,. But this study shows significant therapeutic efficacy, including prolonging survival, requires a more step-wise approach. When the plant-based virus particles and the drugs were able to work on their own, we saw the greatest benefit.”
The researchers will move on to investigate mechanisms behind the potato virus particles’ anti-tumor effects. The research has been published in the journal Nano Letters. The research paper is headed “Combination of Plant Virus Nanoparticle-Based in Situ Vaccination with Chemotherapy Potentiates Antitumor Response.”