Nanoparticles will help the immune system in the fight against cancer

Nanoparticles will help to improve immunotherapeutic methods of cancer treatment

Nanonews Network based on University of Georgia materials: UGA researchers use nanoparticles to fight cancer

Scientists at the University of Georgia are developing a treatment method in which nanoparticles are used to recognize cancer cells and strengthen the attack on them by the immune system, "reprogramming" an integral part of immunity – dendritic cells. An article about the new study was published in the online edition of the journal ACS Nano (Marrache et al., Ex Vivo Programming of Dendritic Cells by Mitochondria-Targeted Nanoparticles to Produce Interferon-Gamma for Cancer Immunotherapy).

The human body constantly lives according to the laws of "wartime". The main person responsible for maintaining order is the immune system, which recognizes and destroys hordes of invading bacteria and viruses that threaten the normal functioning of cells, organs and tissues and the very life of the body.

The immune system does its job well, but it's not perfect either. So, many cancer cells are able to avoid detection by the immune system – because they are practically indistinguishable from normal ones – which allows them to multiply freely, forming life-threatening tumors, while the body's defenders know nothing about this threat.

Shanta Dhar and her colleagues want to "push" the immune system to more active actions. "What we're working on is relevant for breast cancer," says Dhar, associate professor of chemistry at Franklin College of Arts and Sciences University of Georgia. "In our article, for the first time, it is reported about the possibility of strengthening the immune system's attack on breast cancer cells with the help of targeted nanoparticles, the target of which are mitochondria, and light. This is a completely new way."

In their experiments, Dhar and her colleagues exposed cancer cells in a Petri dish to specially designed nanoparticles, the size of which is 1000 times smaller than the thickness of a human hair. Nanoparticles penetrated into cells and into mitochondria – organelles responsible for the production of energy needed by cells for growth and reproduction. Then the nanoparticles inside the mitochondria were activated by laser light with a wavelength allowing it to penetrate into the tissues (660 nm). Activated nanoparticles disrupted normal processes in cancer cells, eventually causing their apoptosis and necrosis. Dead cancer cells were "introduced" to dendritic cells, one of the main components of the human immune system.

"We are potentially able to overcome some of the traditional disadvantages of today's dendritic cell–based immunotherapy," says Sean Marrache, a PhD student in the Dhar laboratory. "By targeting the mitochondria of cancer cells with nanoparticles and presenting activated cancer cells to dendritic cells, we found that dendritic cells began to synthesize a large number of signaling molecules that they usually do not produce. These chemical signals are considered an integral part of the effective stimulation of the immune system."

One of the limitations of the clinical use of immunotherapeutic cancer treatments based on dendritic cells (DC) is the low activity of the T-cell response to tumor-specific antigens. Shanta Dhar and her colleagues studied the immunotherapeutic potential of targeted nanoparticles (NP) based on a biodegradable polymer and a photosensitizer (T-ZnPc-NP) – zinc phthalocyanine (ZnPc), whose targets are mitochondria. Tumor antigens obtained as a result of light stimulation of T-ZnPc-NP in breast cancer cells activate the production by dendritic cells of large amounts of gamma interferon, an important cytokine secreted by T cells and natural killers. The data obtained by American researchers open up the potential possibility of using the supernatants of light-activated cancer cells treated with mitochondrial-oriented nanoparticles as effective therapeutic and prophylactic vaccines. (Fig. ACS Nano)

"Dendritic cells recognized cancer as something alien and began to produce high levels of gamma interferon, which warns other components of the immune system about the presence of strangers and signals the need to attack them. We essentially used cancer against him," Dhar adds.

As the researchers warn, the results of their work are preliminary, and this approach only works on certain forms of breast cancer. But if the process can be improved, one day it will be able to serve as the basis for a new anti-cancer vaccine for the prevention and treatment of this disease. In particular, scientists hope that it will be able to help patients with metastases.

If the process can be translated into a clinical method, doctors will be able to take cancer cells from biopsy samples of the patient's tumor, kill them with nanoparticles and, under controlled laboratory conditions, obtain large quantities of activated dendritic cells, which can then be injected into the patient's body. Once in the blood, the activated cells will be able to warn the immune system about the presence of cancer. "We can now do all this with the help of nanotechnology," concludes Dhar. "If we can improve this process, we will probably be able to use similar methods to fight other forms of cancer."

Portal "Eternal youth" http://vechnayamolodost.ru 19.08.2013