New drug combo identified for liver cancer via CRISPR-Cas9 screening
A research team from the University of Hong Kong’s LKS School of Medicine (HKUMed) has successfully repurposed an approved drug, the vasodilator ifenprodil, for use in combination with sorafenib, a first-line drug approved by the FDA, for the treatment of hepatocellular carcinoma (HCC). . This study relied on their CombiGEM-CRISPR v2.0 screening platform1 to accelerate the search among the many possible drug combinations to inhibit drug targets in the genome for the treatment of HCC. The results are now published in Research against cancer.
Liver cancer is the sixth most common cancer and the third leading cause of cancer-related death worldwide. Despite the promising initial response to targeted molecular therapies, tumors are often susceptible to developing drug resistance. This is no exception for sorafenib, the mainstay of HCC treatment, and the treatment options available are very limited. Drug combination is a strategy to expand cancer treatment options to reduce the risk of drug resistance and tumor relapse that often occurs in stand-alone treatment. The simplicity and precision of CRISPR-Cas9, which uses guide ribonucleic acids (RNA) to knock out all genes in the genome, makes it an excellent tool for identifying targets for potential drug discovery and development.
Using the CombiGEM-CRISPR v2.0 screening platform to generate multiplexable gene knockouts, this study rapidly characterized cancer cell survival after double-gene knockouts in a DNA barcode-linked cell pool specifying the types of genetic alterations they carry. Instead of using a conventional drug screening array that requires the manipulation of many independent multi-wells, this platform only requires a simple experimental setup because the number of DNA barcodes carried by a large population of cells cultured in the same culture dish could be counted in high volume via high-throughput sequencing technologies. Through the screening of genes and their combinations from which successes can be translated directly into drug combinations using existing drugs, unconventional drugs and drug combinations could be discovered and reused for the treatment of cancers.
Through combinatorial CRISPR-Cas9 screening focusing on a set of drug targets whose expressions are up-regulated in HCC cancer stem cells, the HKUMed research team identified two combinations harboring a common target known as NMDAR1 and its paired targets are two kinases (FLT4 and FGFR3) whose corresponding drug inhibitor is first-line sorafenib. Specifically, genetic ablation of identified gene combinations inhibits the growth and self-renewal capacity of HCC cells. Based on The Cancer Genome Atlas database, the research team also unveiled the clinical importance of NMDAR1 in HCC, where HCC patients with low level of NMDAR1 expression show better outcomes. of survival.
The team also revealed the enhanced inhibition effect of the corresponding drug combination and their underlying molecular mechanisms. Co-administration of ifenprodil and sorafenib markedly reduced cell growth and strain in several HCC cell lines, patient-derived organoids, and tumor xenograft models. Additionally, the team also showed that upregulation of the unfolded protein response, triggering of cell cycle arrest, and downregulation of genes associated with WNT signaling and strain could explain the increased effects of the drug combination.
Ifenprodil has been used as a vasodilator in countries, including Japan and France, with a known history of safety in humans. Combined with first-line sorafenib, the HKUMed research team successfully demonstrated that this two-drug regimen profoundly suppressed the growth and self-renewal capacity of HCC cells.
“Successful drug reuse saves the cost and time that would otherwise be required to develop new therapeutic agents with an uncertain efficacy and safety profile. It also increases the chances of clinical translation of the results from the laboratory to the bedside, as the identified drug combination could be easily tested in future trials for the treatment of HCC. Our work has identified a potentially useful drug combination to be tested further for the treatment of HCC patients from approved drugs, which could potentially save or prolong the lives of patients,” said Associate Professor Dr Stephanie Ma. at the School of Biomedical Sciences, HKUMed, who co-led the study.
“The application of the CombiGEM-CRISPR v2.0 platform has expanded our reach in finding effective combinations of actionable targets and approved/repurposed drugs for HCC in a simple and rapid manner, and could be extended to more other cancers and diseases,” added Dr. Alan Wong Siu-lun, Assistant Professor, School of Biomedical Sciences, HKUMed, who co-led the research.