hTERT Gene Modification Using CRISPR-dCas9-dnmt3a System as a Therapeutic Approach Against Glioma

Abnormal DNA methylation patterns have been reported in various diseases, including different cancers. CRISPR/Cas9 is a low-cost and highly effective gene editing tool that has lately revolutionized biotechnology. Studies have shown that the CRISPR/Cas9 system can effectively target and correct methylation.

Telomerase plays a survival role for cancer cells. It is encoded by the hTERT gene. The effectiveness of CRISPR/Cas9 in targeting hTERT to treat glioma cancer cells was assessed in this study.

EF1a-hsaCas9-U6-gRNA vector carrying sgRNA and Cas9 hybrids were used to transfect U87 glioma cells. Four and eight μg/mL polybrene concentrations were investigated to improve transfection efficiency. The expression level of hTERT that has undergone metabisulfite modification was assessed using real-time PCR. Flow cytometry and Western blotting were also used to determine whether telomerase was present in the cells. High-resolution melting analysis (HRM) was used to examine the hTERT promoter's methylation. Finally, flow cytometry was used to measure the apoptotic rate of transfected U87 cells.

The findings demonstrated that gRNA significantly boosted transfection effectiveness. Significant variations were seen in the expression of hTERT in U87 cells at 4 μg/mL polybrene and 80 μg/mL transfection compared to transfection without gRNA and basal cells. Flow cytometry showed a decrease in hTERT levels in transfected cells. Furthermore, transfection with gRNA increased U87 cell apoptosis compared to transfection without gRNA.

It appears that the designed CRISPR/Cas9 system can reduce hTERT expression and telomerase activity and thus inhibit glioma cell growth.