How to get to the unfinished cancer cells

Cancer cells find protection in the bone marrow

Kirill Stasevich, CompulentaOur immune system should be able to detect not only bacteria with viruses, but also cancer cells.

Therefore, many cancer drugs are being developed in order to attract the attention of the immune system to the malignant cells that it once viewed. Usually, such a drug turns out to be antibodies that specifically bind to a protein on the membrane of a cancer cell and attract the attention of macrophage cells. Macrophages come to the cancer cell and eat it.

However, some tumor cells still remain in the body, and after a while the disease begins anew. Researchers from the Massachusetts Institute of Technology (USA) propose a method that would increase the effectiveness of such immunoprovoking anticancer agents. Michael Hemann and his colleagues experimented with mice injected with human cells programmed to turn into lymphoma. Then the mice were given the drug alemtuzumab. With its help, it was possible to cleanse the body of most cancer cells, but some of them still remained in it - and not anywhere, but in the bone marrow. In general, the bone marrow for many types of malignant diseases serves as a kind of sump, where the disease can wait out the drug attack.

In the journal Cell, the authors of the work (Pallasch et al., Sensitizing Protective Tumor Microenvironments to Antibody-Mediated Therapy) write that antibodies also bound to those malignant cells that were hiding in the bone marrow, but macrophages did not react to this in any way. It turned out that prostaglandins, special lipids that the bone marrow needs to protect the immune cells maturing in it, had a soporific effect on them. That is, cancer cells, we can say, enjoyed someone else's protection.

Scientists have found a way to get to the cancer cells hiding in the bone marrow. Using antibodies together with Cyclophosphamide (CTX), another antitumor agent, they ensured that the sick mice remained alive throughout the experiment, that is, for a year and a half. Cyclophosphamide, according to scientists, changed the microenvironment of cancer cells in the bone marrow, so that macrophages began to hunt for them again. At the same time, it was important to administer both drugs simultaneously, although alemtuzumab could be replaced with rituximab, another antitumor immunoglobulin drug.

Diagram from the article in Cell – VM

Cyclophosphamide itself is used in conventional chemotherapy, but in combination with drug antibodies, it works in much lower concentrations, which reduces the strength of side effects. In the future, the researchers plan to test such combination therapy on other types of cancer, including breast and prostate tumors, which are characterized by a high tendency to form metastases in the bone marrow, and it is especially difficult to get rid of them after that.

Prepared based on the materials of MIT News: New weapon fights drug-resistant tumors.

Portal "Eternal youth" http://vechnayamolodost.ru03.02.2014