Cancer treatment: bacteria coated with nanoparticles
Bacteria for DNA vaccine delivery
"AIR"One of the modern methods of cancer therapy is the use of DNA vaccines.
As a result of the work carried out at universities in China and Singapore, a new method of vaccine delivery has been developed. For this purpose, bacteria coated with special nanoparticles were used. The results of the work are published in the journal Nano Letters (Hu et al., Engineering Nanoparticle-Coated Bacteria as Oral DNA Vaccines for Cancer Immunotherapy – VM).
The easiest and most comfortable way for the patient to deliver the DNA vaccine is oral (taking the medicine by mouth). However, once in the gastrointestinal tract, the drug can be destroyed by digestive enzymes; in addition, difficulties may arise at the stage of its absorption from the intestine into the blood.
To solve these problems, the staff of Zhejiang University (China) and Nanyang Technological University (Singapore) have developed a new unusual way. They used a bacterium from the genus salmonella as the main carrier of the vaccine. Of course, a weakened strain of the bacterium was used, which is not capable of causing the disease. A DNA vaccine was introduced into the bacterium, which is a gene encoding the human VEGFR2 receptor. This receptor is responsible for the growth of blood vessels. If such a receptor is blocked, the growth of new vessels will stop and the tumor will not be able to develop, since it will not have enough nutrients and oxygen.
However, such a bacterium turns out to be unstable in the gastrointestinal tract. To overcome this difficulty, the authors of the work used special nanoparticles. They were made of negatively charged polymer molecules. Since the surface of salmonella carries a positive charge, these particles stuck to it, forming a kind of protective shell. As a result, such a bacterium easily overcame the acidic environment of the stomach and, reaching the lower parts of the intestine, began to multiply, causing the expected response of the immune system to salmonella itself and the DNA vaccine contained in it.
Drawing from the article in Nano Letters – VM.
Now the authors of the work plan to develop the technique by testing other types of bacteria and nanoparticles. The developers' plans include testing other types of DNA vaccines aimed at other types of oncological diseases, as well as some diseases of the immune system.
Portal "Eternal youth" http://vechnayamolodost.ru28.05.2015