Knockdown of STIL suppresses the progression of gastric cancer by down-regulating the IGF-1/PI3K/AKT pathway.

SCL/TAL1 interrupting locus (STIL) regulates the mitotic centrosome to promote the centriolar replication and cell cycling, and is associated with malignancies. However, the role and mechanism of STIL in gastric cancer (GC) remain elusive. STIL expression in GC tissue microarray was detected by immunohistochemistry (IHC). GC cells were transduced with control lentivirus or lentivirus for expression STIL-specific shRNA and the effect of STIL silencing on the malignant behaviors of GC cells was measured in vitro and in vivo. The potential mechanisms underlying the action of STIL were analyzed by transcriptome microarray and bioinformatics. STIL expression was up-regulated in GC tissues both in our cohort and the data from the cancer genome atlas, and positively associated with T stage and poor overall survival of GC patients. Knockdown of STIL significantly inhibited the proliferation and clonogenicity of human GC cells and attenuated the growth of implanted GC in vivo. Furthermore, STIL silencing induced cell cycle arrest in G2/M phase and apoptosis of GC cells. Transcriptome analysis indicated that STIL silencing modulated many gene expression, particularly for down-regulating the IGF-1/PI3K/AKT pathway. In addition, treatment with SC79, an AKT activator, significantly mitigated the effect of STIL-silencing in GC cells. In conclusion, STIL promotes gastric carcinogenesis and progression by enhancing the IGF-1/PI3K/AKT signaling, and STIL may be a novel target for intervention of GC.