SALL4 Regulates Glycolysis To Promote Malignant Progression Of Gastric Cancer And Its Mechanism

Objective: To study the role of SALL4 in glycolysis of gastric cancer cells,to explore the specific mechanism by which SALL4 regulates the expression of HK-2 to affect the glycolysis level of gastric cancer cells so as to promote its malignant progression,to provide theoretical and experimental basis for elucidating the relationship between SALL4 and glycolysis of gastric cancer cells and malignant progression of gastric cancer,and to provide a new idea and target for molecular diagnosis,treatment and prognosis assessment of gastric cancer.Methods: According to the expression of SALL4,two pairs of gastric cancer cell lines MGC-803,SGC-7901,HGC-27 and AGS were selected for the knockdown and overexpression experiments of SALL4.The glycolysis levels of gastric cancer cells were detected by glucose uptake,lactate production,lactate dehydrogenase activity,ATP level and hexokinase activity analysis kits.qRT-PCR and Western blot were used to detect the expression changes of SALL4,glycolytic related genes and proteins.Then the downstream target genes of SALL4 were screened by microarray.Then the dual luciferase reporter gene assay was used to verify the binding effect of SALL4 on HK-2 gene in gastric cancer cells,and chromatin immunoprecipitation assay was used to verify the regulatory effect of SALL4 on HK-2 gene.Transwell migration assay,Matrigel invasion assay,cell counting assay and colony formation assay were used to evaluate the biological function of gastric cancer cells.The effect of SALL4 on glycolysis,growth and metastasis of gastric cancer was studied in vivo by establishing peritoneal metastatic tumor and subcutaneous tumor bearing models in nude mice.Results: SALL4 knockdown inhibited the glucose uptake,lactate production,lactate dehydrogenase activity,ATP level and hexokinase activity in gastric cancer cells,and decreased the expression of glycolytic related genes and proteins.Overexpression of SALL4 led to the opposite effect.Microarray analysis uncovered that HK-2 might be the directed target of SALL4.The dual luciferase reporter assay verified that SALL4 could bind to HK-2,and then the chromatin immunoprecipitation assay further confirmed the regulatory effect of SALL4 on the expression of HK-2 gene.HK-2 knockdown abrogated the promoting effect of SALL4 overexpression on glycolysis of gastric cancer cells,indicating that HK-2 acts as a downstream effector molecule of SALL4.Moreover,we found that the interference of HK-2 expression could reverse the promotion of gastric cancer cell proliferation,migration and invasion by SALL4,suggesting that SALL4 may promote the malignant progression of gastric cancer by upregulating the expression of HK-2.Conclusions: SALL4 promotes malignant progression of gastric cancer through HK-2-mediated glycolysis,revealing a new mechanism for SALL4 to play the role of oncogene in gastric cancer from the perspective of tumor metabolism.