Background: The impact and potential molecular mechanisms of SST in the occurrence and development of GC have not been determined.
Materials and Methods: Two pairs of sgRNA and reporter were designed according to targeting sequence of SST gene for double-nicking. Plasmids were transfected into 293T for selecting sgRNA with higher cutting efficiency. The subline which has knocked-out SST  gene were selected by FACS and verified by sequencing and expression level. Moreover, the migration and invasion ability was evaluated by wound healing and transwell after knocking out SST. Besides, the protein expression of SEMA5A and KLF2 were observed by Western blotting and LSCM. Last, we detected the expression levels of SST, SEMA5A, and KLF2 in GC tissues by Western blotting.
Results: The results revealed that the new subline 1E9, which had knocked out SST  gene, was established by CRISPR/Cas9. In addition, the knockout of SST in GC cells markedly increased migration and invasion ability. The results also demonstrated that the knockout of SST increased the expression of SEMA5A and KLF2. The expression level of SST was decreased in GC tissues, and its decrease was associated with overexpression of SEMA5A and KLF2.
Conclusion: SST plays an inhibitory role in the migration and invasion of GC cell BGC823. The protein expression levels of SEMA5A and KLF2 were enhanced in GC cells and tissues lacking SST expression.
Keywords: somatostatin, CRISPR/Cas9, gastric cancer, migration, invasion