Scientists at Kyoto University in Japan have identified a mechanism by which cancer cells become resistant to treatment by getting rid of chemotherapy drugs. This is reported in an article published in FEBS Letters, and the study is summarized in a press release on MedicalXpress.
The key role in the development of incurable forms of cancer is played by the ABC transporter proteins, which perform transport functions: import of nutrients into the cell, export of toxic substances, and regulation of lipids in cell membranes. For example, ABCB1 is responsible for the export of toxic compounds from the cells of vital organs such as the brain, testes, and placenta. These toxic substances can be drugs that target cancer cells.
The researchers grew crystals of the ABCB1 protein before and after exporting the compound. They then performed X-ray analysis to determine the differences between the two structures.
It turned out that the substances intended for export enter the ABCB1 cavity in the part of the protein located from the inner part of the membrane. This causes structural changes in the protein, for which the energy of ATP is spent, after which the gate opens through which the substance leaves the cell. This mechanism is different from that of other carrier proteins.
