Metastatic Cancer Cells destroyed by CRISPR Technique

Tel Aviv University (TAU) scientists announce that the CRISPR/Cas9 method is successful in the treatment of metastatic cancers, which they believe represents an important step in seeking a cure for cancer. The researchers created a delivery system based on lipid nanoparticle that targets cancer cells directly and kills them by genetic manipulation. The system of CRISPR-LNPs carries a messenger RNA encoding the CRISPR enzyme Cas9 as a molecular scissor that cuts the DNA of the cells.

The study was carried out in the laboratory of Dan Peer, PhD, VP of R&D and Head of the Precision Nanomedicine Laboratory at TAU's Shmunis School of Biomedicine and Cancer Research. The research was carried out by Daniel Rosenblum, PhD, together with Anna Gutkin, a PhD student, and Peer's laboratory colleagues and other collaborators.

The study “CRISPR-Cas9 genome editing using targeted lipid nanoparticles for cancer therapy” appears in Science Advances.

Low editing efficiency in tumours and possible toxicity of current delivery systems have hindered the use of CRISPR-Cas9 technology for cancer therapeutics. Here for the delivery of Cas9 mRNA and sgRNAs using a novel amino-ionizable lipid, we identify a safe and effective lipid nanoparticle (LNP)," the investigators report.

A single intracerebral injection of CRISPR-LNPs into aggressive orthotopic glioblastoma against PLK1 (sgPLK1-cLNPs) allowed in vivo gene editing of up to ~70%, which induced tumour cell apoptosis, inhibited tumour growth by 50%, and improved survival by 30%. CLNPs have also been engineered for antibody-targeted delivery to enter disseminated tumours. EGFR-targeted sgPLK1-cLNPs intraperitoneal injections induced their selective uptake into disseminated ovarian tumours, allowed in vivo gene editing of up to ~80 percent, inhibited tumour development, and increased 80 percent survival.

The ability to disrupt gene expression in vivo in tumours opens new opportunities for the treatment and study of cancer and future applications for noncancerous tissue targeted gene editing.

This is the first study in the world to prove that the genome editing system CRISPR can be used in a living animal to treat cancer effectively," said Peer. "It is important to stress that this is not chemotherapy. There are no side effects, and a cancer cell treated in this manner can never again become active. Cas9's molecular scissors cut the DNA of the cancer cell, thereby neutralising it and preventing replication permanently.

Peer and his team selected two of the deadliest cancers to explore the possibility of using this technology to treat cancer: glioblastoma and metastatic ovarian cancer. With a life expectancy of 15 months after diagnosis and a five-year survival rate of just 3 percent, glioblastoma is the most aggressive form of brain cancer . The researchers found that the average life expectancy of mice with glioblastoma tumours was doubled by a single CRISPR-LNP injection, increasing their overall survival rate by around 30 percent.

Ovarian cancer is a significant cause of death for women and is the female reproductive system's most deadly cancer. When metastases have already spread across the body, most patients are diagnosed at an advanced stage of the illness. Just a third of patients survive this disorder, despite improvement in recent years. Treatment with CRISPR-LNPs in a mouse model of metastatic ovarian cancer improved their overall survival rate by 80 % .

Our ability to interrupt, restore or even replace genes in a customised way has been revolutionised by the CRISPR genome editing technology, capable of defining and altering any genetic fragment, Peer continued. Clinical implementation is still in its infancy, despite its extensive use in science, since an efficient delivery system is required to deliver the CRISPR to its target cells safely and accurately. The delivery system that we have built targets the DNA responsible for the survival of cancer cells. This is a groundbreaking therapy that has no successful treatment for aggressive cancers today.

The researchers state that the technology opens up many new possibilities for treating other forms of cancer, as well as rare genetic disorders and chronic viral diseases such as AIDS, by showing its potential in the treatment of two aggressive cancers.

Now we expect to move on to studies with genetically very interesting blood cancers, as well as genetic disorders such as Duchenne muscular dystrophy,' Peer explained. It is possible that it will take some time for the latest drug to be used in humans, but we are hopeful. The whole molecular drug scene using messenger RNA is thriving... in fact, this theory is the basis of most COVID-19 vaccines currently under development.

"Twelve years ago, when we first talked about mRNA therapies, people thought it was science fiction. I assume that for both cancer and genetic disorders, we will see many tailored therapies based on genetic messengers in the near future. We are now negotiating with foreign companies and foundations through Ramot, TAU's Technology Transfer Business, to introduce the benefits of genetic editing to human patients.