A new method of catching cancer cells in the blood
Traveling cancer cells will catch on DNA tentacles
Kirill Stasevich, CompulentaSome malignant cells break away from the tumor and begin to wander through the bloodstream.
These are not always metastatic agents, it's just that the cell has lost contact with the others for some reason. And such a traveler is just a storehouse of useful information, with her help you can learn a lot about the condition of the tumor and further treatment prospects. However, it is very difficult to catch it. Until now, researchers have used antibodies for this: blood was passed through the thinnest tubes coated from the inside with antibodies against the membrane proteins of the cancer cell. However, due to the fact that the antibodies themselves are not too large and do not protrude very much into the lumen of the tube (only a few nanometers), the procedure for collecting traveler cells turned out to be too long and inefficient.
Researchers from the Massachusetts Institute of Technology (USA) have figured out how to improve cell catching. They used DNA strands consisting of a series of repeats. The DNA sequence was selected to interact with specific proteins of cancer cells. The filaments were up to several hundred microns long, and they sat on the ribbed surface of the capillary. Due to the irregularities that formed the Christmas tree pattern, the liquid, when passed through the capillary, swirled, thereby increasing the likelihood that the cell would interact with the DNA tentacle.
Cells (red) passing through a microcapillary with DNA strands (green) (photo of the authors of the work).
As a result, as the researchers write in the journal PNAS (Zhao et al., Bioinspired multivalent DNA network for capture and release of cells), they managed to increase the speed of blood pumping through the system by 10 times compared to previous versions. At the same time, 60 to 80% of the wandering cancer cells were deposited on the DNA. Now the device allows you to pump blood at a rate of 1 ml / h, but in the near future the authors of the work are going to scale their invention by increasing the speed by 100 times. Since cells are caught on DNA, it is not difficult to separate them from the "hook" – you just need to process them with DNA-splitting enzymes.
Using different DNA lengths and different sequences, it is possible to vary the specificity of the method, adjusting it, for example, for certain types of cancer. Moreover, the method, as the researchers believe, is suitable for catching very rare cells – for example, embryo cells in the blood of a pregnant woman. It is very difficult to catch such an object, but it is worth it, because with its help you can find out such details about the well-being of a growing fetus that cannot be found out by conventional methods.
Prepared based on the materials of MIT: News On the hunt for rare cancer cells.
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