[Establishment and validation of human cancer cell lines with stable Cas9 expression]

Objective: To establish human cancer cell strains with stable Cas9 expression, and to validate the gene editing activity of Cas9 for simple gene editing in future study. Methods: Fifteen cancer cell lines of different tissue origins were infected with pLv-EF1α-Cas9-Flag-Neo or pLv-EF1α-Cas9-Flag-Puro by lentivirus and clone selection was employed to screen Cas9 stably expressed cancer cell lines. Afterward designed guide RNA vectors targeting TSC22 gene were transiently transfected into 3 of cell lines, and subsequently the gene editing activity of Cas9 was evaluated by genomic PCR, sequencing and Western blot. Results: Sixty-nine human cancer cell strains with stable Cas9 expression from different cancers were established, and by transient transfection with designed guide RNA, long fragment deletion was detected in TSC22 gene. Conclusions: Sixty-nine human cancer cell strains are successfully established with stable expression of Cas9 protein and gene editing activity. These cell strains may be employed in large-scale drug screening, screening of new drug targets and gene function investigation.