Science Sub-Journal: Total survival rate up to 80%! CRIS...

Cancer treatment using CRISPR-Cas9 technology has been hampered by inefficient tumor editing and the potential toxicity of existing delivery systems.
recently, researchers at Tel Aviv University developed a safe and effective CRISPR-Cas9 drug system based on lipid nanoparticles that specifically targets cancer cells.
in mice with glioblastoma and ovarian cancer models, the body editing rate was 70%-80%, and the total survival rate was as high as 80%.
study was published in Science Advances on November 18.
photo source: Science AdvanceCas9 Nuclease is guided by single-stranded wizard RNA (sgRNA) to modify specific chromosomal DNA sequences by inducing sequence-specific double-strand break (double-strand break, DSB).
, however, the large size of Cas9 (160 kDa, 4,300 bases) and sgRNA (approximately 31 kDa, 130 bases) is an obstacle to traditional and non-viral delivery systems.
addition, the delivery system currently used for non-liver tissue and tumors can only lead to relatively low gene editing rates.
to treat cancer effectively, more editing efficiency is needed.
lipid nanoparticles (LNP) are clinically approved non-viral nucleic acid delivery systems that can transport large payloads.
ionized cation lipids are the key components of LNP, which can effectively carry out nucleic acid encasing, cell transport and internal release.
In order to overcome the load limitations of currently available LNP preparations, LNP was designed to encase Cas9 mRNA and sgRNA using ionized cation lipids from novel ionized amino lipid libraries (Figure A below).
series of comparisons, L8-cLNP performed best and was chosen for further study (Figure B below).
(A) CRISPR LNP (cLNP).
a microflow-controlled lipid blend to build cLNP encased in Cas9 mRNA and sgRNA.
(B) the chemical structure of ion ionotic amino lipids screened from the library.
(Source: Science Advances) to assess CRISPR LNP's potential for cancer treatment, the two main problems of CRISPR-Cas9 therapy, namely potential toxicity and immunogenicity, need to be addressed first.
preliminary study assessed liver toxicity, blood cell counts, and serotonin cytokines 24 hours after mice were intravenously injected with L8-cLNP-wrapped green fluorescent protein (GFP) sgRNA (sgGFP-cLNP) (1 mg/kg).
results did not show significant clinical symptoms of toxicity.
that although preclinical development requires a broader potential toxicity assessment, these results show that L8-cLNP is not toxic or immunogenic when given to the system at the relevant dose.
after in vitro experiments observed higher gene editing efficiency, the scientists conducted further studies in mice with models of glioblastoma and metastatic ovarian cancer to assess whether it could be converted into in vivo therapy.
glioblastoma is the most invasive brain cancer, with a life expectancy of 15 months and a five-year survival rate of only 3%.
studies have shown that a single intra-brain injection of CRISPR LNP (sgPLK1-cLNP) in invasive in-place glioblastoma in mice can increase the gene editing rate in the body by about 70%, significantly reduce tumor growth, extend the medium survival by about 50%, and increase the overall survival rate to 30% (figure H below).
-editing therapy in mice with glioblastoma models (Source: Science Advances) For most tumors, especially metastases or hematological tumors, the treatment strategy requires systemic medication.
, however, most LNP is trapped in the liver and other central organs and cannot be effectively absorbed by tumor cells after a full-body injection.
targeting gene editing strategies can enhance gene editing capabilities on tumor cells and reduce toxicity and editing to non-target cells.
cLNP is also designed to target antibodies in order to reach exudable tumors.
Injection of EGFR-targeted sgPLK1-cLNP into the abdominal cavity of metastatic ovarian cancer model mice can be selectively ingested into extrinsic ovarian tumors, with a gene editing rate of up to 80% and an overall survival rate of 80%.
ovarian cancer model mice with gene-editing therapy (Source: Science Advances) Scientists say the new technology opens up new possibilities for treating other types of cancer, as well as chronic viral diseases such as rare genetic diseases and AIDS, by demonstrating the potential to treat two invasive cancers.
Dan Peer, who led the study, said: "This new treatment may take some time to be used in humans, but we are optimistic about it.
mRNA-based drugs are booming, and in fact most COVID-19 vaccines currently under development are based on this principle.
12 years ago, when we first talked about treating with mRNA, people thought it was science fiction.
believe that in the near future, we will see many personalized gene messenger-based therapies being used to treat cancer and genetic diseases.
through Ramot, a technology transfer company at Tel Aviv University, we are already in talks with multinational companies and foundations to use gene editing technology for the benefit of mankind.
"References: 1- Revolutionary CRISPR-based genome editing system treatment destroys cancer cells (Source: medical press) 2 s Daniel Rosenblum et al, CRISPR-Cas9 genome editing using targeted lipid nanoparticles for cancer for therapy, Science Advances (2020) DOI: 10.1126/sciadv.abc450