HTERT Influences Invasion And Migration Of Gastric Cancer Cells Through Regulation Of Gli1 Expression

Background: Gastric cancer(GC) remains one of the leading causes of cancer-related death worldwide. The data from GLOBOCAN 2012 showed that an estimated 951,600 new GC cases and 723,100 deaths occurred in 2012. GC rates are generally about twice as high in men as in women and vary widely across countries. In general, incidence rates are highest in Eastern Asia. Although current diagnosis and treatment has been improved, the prognosis of GC is very poor and the 5-year survival rate is still low. Aberrant Hh pathway is responsible for the tumorigenesis of several disparate human cancers, including GC. Gli1 is one of the transcription factors and could regulate most downstream target genes of Hh pathway. In our previous study, we found that both Gli1 and h TERT were overexpressed in GC and correlated with metastatic capacity in GC tissue. Moreover, the expressions of h TERT and Glil were correlated in GC, but the regulatory mechanisms between h TERT and Gli1 remain unknown.ObjectiveThe aims of the present study are to evaluate the role of the Hedghog signaling pathway transcription factor Gli1 in GC development and progression and to clarify cytology mechanisms of its high expression with lymph node metastasis and distal metastasis. We also determine the regulatory mechanisms between h TERT and Gli1.Methods:1. q RT-PCR and Western blot were employed to quantify the expression level of Gli1 in GCcell line SGC-7901 after transfection with si-Gli1.Wound-healing assay and transwell migration analysis were employed to determine the migration ability of SGC-7901 after transfection with si-Gli1.2. q RT-PCR and Western blot were employed to quantify the expression level of Gli1 and h TERT in GC cell line SGC-7901 after transfection with h TERT vector. After h TERT, PGL3-basic-Gli1 and p RL-TK were cotransfected into the SGC-7901 cells for 24 h, the assay was performed via dual luciferase reporter assay system.Results:1. The expression levels of Gli1 at both m RNA and protein were downregulated in SGC-7901 cells after transfection with si-Gli1.2. The migration of SGC-7901 cells transfected with si-Gli1 was slower than that of the cells transfected with si-NC in wound-healing assay.3. The numbers of migratory cells transfected si-Gli1 were significantly less than those of the cells transfected with si-NC in transwell migration assay.4. The expression levels of h TERT and Gli1 at m RNA and protein were upregulated in SGC-7901 cells after transfection with h TERT vector.5. Overexpression of h TERT enhanced the relative luciferase activity.Conclusions:1. The Hedehog pathway transcription factor Gli1 enhances the migratory ability of GC cells in vitro.2. h TETR could regulate the expression of Gli1 by targeting the promoter region of Gli1.