For the greatest chance of survival, cancer screening needs to detect the disease before symptoms appear. Current cancer detection involves blood tests, urine tests, DNA tests, and/or medical imaging, however, screening is not always accurate with false-positive results and subsequent invasive procedures, or false-negative results, where an existing cancer is missed. This means it is not always clear if the benefits of cancer screening outweigh the risks of the detection technique and any ensuing unneeded procedures.
DNA computer detects cancer cells
Now, a study from researchers at Duke University develops a cancer-detecting tool using tiny circuits made of synthetic DNA to identify single cancer cells by the molecular signatures on their surface. The team states their technology could be used as a screening tool to help rule out cancer, which could mean fewer unnecessary follow-ups or to develop more targeted cancer treatments with fewer side effects. The study is published in the Journal of the American Chemical Society.
Previous studies show when similar techniques have been used to screen for cancer there have been high rates of misidentifications due to a mixture of cells sporting one or more of the proteins a DNA circuit is designed to screen for, with no single cell type possessing them all.
This is because each type of cancer cell has a characteristic set of cell membrane proteins on its cell surface. The current study minimizes the number of misidentifications by designing a DNA circuit with the prerequisite it must latch onto the specific combination of proteins native to a cancer-cell type to work.
The current study engineers a DNA computer where each basic element of a DNA circuit consists of two synthetic DNA strands, one of which is shaped liked a hairpin, and the other that acts as a lock and tether.
Results show these two strands fold together to attach to a specific protein on the cell’s surface. A strand of initiator DNA is then added to open the hairpins and light the cell up. Data findings show leukemia cells were distinguished from other types of cancer within a matter of hours in in vitro experiments.
Detecting cancer cell-by-cell
The lab explains their circuits work by attaching to the outside of a cell and analyzing it for proteins found in greater numbers on some cell types than others; and when a circuit finds its targets, it labels the cell with a tiny light-up tag. They go on to add as the devices distinguish cell types with higher specificity than previous methods, it is hoped their work might improve diagnosis, and afford cancer therapies higher specificity.
The team surmises they have developed a DNA-based computing system capable of detecting cancer on a single-cell basis. For the future, the researchers state they now plan to expand the device to release a small molecule with the ability to alert the body’s immune system to attack the cancer cell.
Source: Duke University
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