CRISPR has gained a lot of attention in recent years, from curing diseases to yielding gene edited crops to modifying the human embryo. Aside from these, scientists are now exploring CRISPR for applications other than gene editing.
CRISPR-Cas9 Used in Detecting DNA
Researchers from the Keck Graduate Institute and the University of California, Berkeley conducted a study by combining CRISPR-Cas9 and a graphene chip to detect DNA, rendering the conventional amplification step unnecessary. CRISPR has a genome-searching capability while graphene is highly sensitive. Utilizing these characteristics, the researchers immobilized CRISPR complexes on graphene-based transistors, allowing them to find and bind their target DNA. Once bound, the conductivity of the graphene material in the transistor changes, which is detected by a reader developed by Cardea Bio– the group’s San Diego-based industry partner.
Based on their paper published in Nature Biomedical Engineering, the researchers were also able to demonstrate the effectiveness of detecting DNA mutations in Duchenne muscular dystrophy (DMD), a genetic disorder that prevents the body from producing dystrophin. This disease is caused by a mutation of the gene and results in progressive muscle degeneration.CRISPR-Cas13: Detecting and Killing Human Cell RNA viruses
Cas13a has been said to be able to bind and cleave RNA in human cells which makes it a potential diagnostic tool to detect viruses, bacteria, or other targets. This is according to the researchers at Zhang Lab of Cambridge, Massachusetts.
Meanwhile, scientists from Harvard and MIT’s Broad Institute also explored CAS13’s ability to detect and kill RNA viruses by combining Cas13’s antiviral activity with its diagnostic capability to create the Cas13-Assisted Restriction of Viral Expression and Readout (CARVER) system. The RNA viruses they targeted are those that are detrimental and incurable human pathogens such as Ebola and Zika.
In addition to this, the scientists tested the antiviral efficiency of CRISPR-Cas13 in human cells infected with diseases such as lymphocytic choriomeningitis virus (LCMV), influenza A virus (IAV), or vesicular stomatitis virus (VSV). They also incorporated the Cas13-based nucleic acid detection technology SHERLOCK (Specific High Sensitivity Enzymatic Reporter UnLOCKing) to enable the system to serve as a “detective” as well.
CRISPR-Cas9: Aids Targeted Cancer Drugs
Targeted cancer drugs, which are designed to target tumor-related proteins and suppress tumor growth and progression have fewer side effects compared to traditional cytotoxic therapies. However, a recent study showed that many targeted cancer drugs may miss their target proteins.
Researchers from Jason Sheltzer’s group used CRISPR-Cas9 to eliminate the genes of the presumed target proteins of these targeted cancer drugs, but the drugs still effectively killed cancer cells. This indicates that the interpretation of the mechanisms of how these cancer drugs function on cancer cells is possibly inaccurate, and they may thwart cancer cells by other mechanisms rather than directly targeting the presumed target proteins. They have also shown promise in some cancer treatments.
This is not surprising at all, as some rationally designed targeted anticancer molecules do not kill cancer cells. The CRISPR technique can help us better understand the pharmacology of such targeted anticancer drugs, thereby leading to more efficiently designed anticancer drugs in the future.
A Promising Future
One of the biggest challenges that we face is how to control the off-target effects of CRISPR as well as recognize its dependency on the PAM (protospacer adjacent motif) sequence, therefore, more research and studies have to be done to improve its accuracy. Moreover, CRISPR applications must be regulated to avoid ethical issues and tragedies.