A new technique for studying cancer mutations may generate approaches for future therapies


Electron microscopic image of a single human lymphocyte. Credit: Dr. National Cancer Institute Knitwear

Cancer and many other diseases are based on genetic defects. The body can often compensate for the defect of a gene; only the combination of several genetic errors leads to the clinical picture. The 3C multiplex technique based on CRISPR-Cas technology developed at Goethe University in Frankfurt now offers a way to simulate millions of these combinations of genetic defects and study their effects on cell culture. These “genetic scissors” allow you to insert, delete, and turn off genes in a specific way. For this purpose, small fragments of genetic material (“unique guide RNA”) are used as “directions” that guide the genetic scissors to specific sections of the DNA, where the genetic scissors become active.

Scientists at Goethe University’s Institute for Biochemistry II have expanded the 3C technique they developed and patented three years ago. 3Cs means covalently closed circular synthesis, because the RNA elements used by CRISPR-Cas are generated with the help of a circular synthesis and therefore distributed more evenly. With an entire library of these RNA rings, any gene in a cell can be specifically treated to change or turn it off.

The new 3C multiplex technique even allows the simultaneous manipulation of two genes in a cell. Dr. Manuel Kaulich explains, “We can produce ‘targeted’ RNA libraries for every conceivable combination of two genes. This allows up to several million combinations to be tested simultaneously in one experiment.”

Until now, the cost and effort of these experiments were very high; the new technique of the research group reduces it, including costs, by a factor of ten. This is because the equipment can produce address books in a very uniform and high quality way thanks to the new 3Cs multiplex technique. “Because of the mediocre quality of the CRISPR-Cas libraries available previously, very large experiments always had to be performed to statistically compensate for errors that occurred,” Kaulich says.

Using the example of several genes involved in degradation processes, the research group demonstrated the potential of 3C’s new multiplex technique: they examined nearly 13,000 bidirectional combinations of genes responsible for recycling (autophagy) processes in the cell. . With its help, the cell breaks down and recycles the “worn out” cell components. Disorders of autophagy can trigger cell proliferation.

“Using the 3Cs multiplex technique, we were able to identify, for example, two genes involved in autophagy whose disconnection leads to uncontrolled growth of “Kaulich explains.” These are precisely the autophagic mutations that occur in every fifth patient with squamous cell carcinoma of the lung. In this way, we can search very efficiently in cell culture experiments which play an important role in cancer, and also in diseases of the nervous and immune systems, and which are suitable as possible targets of therapies “.

Nanoscopes could help CRISPR activate and deactivate genes

More information:
Valentina Diehl et al, Minimized combinatorial CRISPR screens identify genetic interactions in autophagy, Nucleic acid research (2021). DOI: 10.1093 / nar / gkab309

Citation: A new technique to study cancer mutations may lead to approaches for future therapies (2021, June 24) retrieved June 24, 2021 at https://medicalxpress.com/news/2021-06-technique-cancer -mutations-yield-approaches.html

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