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The cause of breast cancer resistance to chemotherapy is found
Last reviewed: 16.10.2021
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Cells of breast cancer for growth require the hormone estrogen. In the treatment of this disease, estrogen receptor blocking is often used, but the tumor has learned to "not notice" such therapy. Scientists managed to find a protein that causes this stability.
Breast cancer is one of the most common forms of cancer; so, in the UK alone, it is found every year in 46 thousand women. More than 75% of cases can be treated with anti-estrogen therapy. The fact is that cancer cells often contain receptors on their surface to the hormone estrogen (it is believed that it is necessary for such cells for growth). Consequently, doctors quite successfully suppress the development of tumors with different estrogen receptor blockers (eg, tamoxifen) - but not when the tumor has resistance to such drugs.
Resistance to chemotherapy is one of the most serious problems of modern oncology. Its severity is largely due to the fact that different types of cancer "get used to" drugs in different ways, and the fight against this phenomenon is literally transformed into a fight with a multi-headed monster. However, in the case of breast cancer, apparently, over the resistance to anti-estrogen therapy is won. Scientists from the Imperial College of the University of London (UK) report that they have found a protein responsible for such stability.
In an article published in the journal Nature Medicine, the researchers describe the LMTK3 protein isolated from human tumor cells resistant to tamoxifen blocking estrogen receptors. In mice, the tumor quickly contracted if scientists genetically suppressed the synthesis of this protein. Patients with poor prognosis who did not respond to chemotherapy showed a high level of this protein in tumor cells compared to patients that can be treated. In addition, the cases of mutations in the LMTK3 gene coincided with how long the cancer patients lived.
Scientists note that the gene for this protein is also found in the closest relatives of a human - a chimpanzee. But the monkeys do not suffer from estrogen-dependent breast cancer at all, although the LMTK3 gene in chimpanzees and humans is very similar. Perhaps the changes in LMTK3 gave us some evolutionary advantages, but at the same time made it more sensitive to this form of cancer. Either way, chimpanzees are not suitable as a test facility for the development of new anticancer therapy, which in some ways complicates the task. On the other hand, the researchers have already determined the direction of the searches: the LMTK3 protein is a kinase, an enzyme that can regulate the activity of other proteins by sewing up residues of phosphoric acid to their molecules. The knowledge of the mechanism of the protein that causes drug resistance should facilitate the overcoming of this very stability.