Shuriken on the tumor
Nanotechnology has opened up exciting new prospects for researchers in the development of targeted antitumor therapy methods, but in practice the task has turned out to be quite difficult. Scientists at Northwestern University, working under the guidance of Professor Teri W. Odom, have created the first nanoparticles that deliver the drug directly to the nucleus of a tumor cell, which can greatly increase the effectiveness of treatment. Moreover, for the first time, they were able to visualize the interaction of nanoparticles with the nucleus of a cancer cell at the nanoscale.
The nanoparticles made of gold are shaped like stars with a diameter of about 25 nanometers, each of which has 5-10 rays. The large surface area of such "nanostars" allows you to attach many drug molecules to them.
The researchers loaded each nanostar with about a thousand single-stranded DNA aptamers AS1411, which perform two functions: selective interaction with nucleolin, a protein whose overexpression is characteristic of cancer cells, and destruction of the cell nucleus. The nucleolin detected both on the surface and in the cytoplasm of tumor cells transported nanoparticles directly to the nucleus of the tumor cell.
After that, the researchers affected the cells with ultrafast light pulses, which destroyed the connections between the aptamers and the surface of the nanoparticles. The shape of the "nanostars" not only allows you to attach a large number of drug molecules to their surface, it also ensures the concentration of light energy at the tips of the rays, which facilitates the process of releasing the drug, which, as a rule, is a difficult task when working with conventional nanoparticles.
Using an electron microscope, the researchers observed how, under the action of AS1411 aptamers, the nucleus of a tumor cell turns from a neat smooth ellipsoid into an irregularly shaped formation with deep indentations of the surface. They also demonstrated that such a change in the shape of the nuclei leads to cell death and a decrease in the viability of the cell population.
After receiving positive initial results, the scientists tested the effect of nanoparticles on 12 other cell lines of different types of human cancer. In all cases, the cells reacted almost identically, which indicates the universality of the proposed approach.
According to Odom, the developed technology has yet to be optimized and, most likely, it will be most effective in the treatment of tumors located close to the surface of the skin, such as skin cancer and some types of breast cancer. Perhaps nanostars will also be useful for surgeons removing malignant neoplasms to destroy single cancer cells that have penetrated into healthy tissue surrounding the tumor.
Article by Dam et al. Direct Observation of Nanoparticle-Cancer Cell Nucleus Interactions is published in the journal ACS Nano.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Northwestern University:
Tiny Hitchhikers Attack Cancer Cells. Gold nanostars first to deliver drug directly to cancer cell nucleus.
12.04.2012