Galectin-1-Mediated High NCAPG Expression Correlates With Poor Prognosis In Gastric Cancers

Objective:Gastric cancer is one of the most common malignant tumors of the digestive tract.More than 1 million new cases of gastric cancer are reported worldwide every year,more than 40%of which occur in China,and most gastric cancer deaths occur in China,which poses a serious threat to the health of the Chinese people.Existing TNM staging can not accurately predict the risk of postoperative recurrence and metastasis in gastric cancer patients.Therefore,exploring new molecular biomarkers related to gastric cancer prognosis is of great significance for improving the prognosis of gastric cancer patients.Existing studies have shown that galectin-1 and non-SMC condensin I complex subunit G(NCAPG)are involved in the malignant biological behavior of many kinds of tumors,they play an important role in the occurrence and development of malignant tumors.However,no scientists have reported whether Galectin-1 and NCAPG are associated in gastric cancer tissues.The aim of this study is to reveal the prognostic value of Galectin-1 and NCAPG expression in gastric cancer.It can more accurately predict the prognosis of gastric cancer patients,and also provide new biological targets for the treatment of gastric cancer patients.Methods:1.Detection and analysis of clinical specimens:Expression of Galectin-1 and NCAPG in gastric cancer and normal gastric mucosa was detected by immunofluorescence and Western Blot.Combined with clinical follow-up data,we analyzed the effect of Galectin-1 and NCAPG expression on the prognosis of gastric cancer patients.2.Stable gastric cancer cell lines overexpressing LGALS1(OE-LGALS1)were established by lentiviral transduction,Western Blot was used to detect the expression of Galectin-1 and NCAPG in gastric cancer cell lines.Quantitative Real-time PCR(qPCR)was used to detect the expression of LGALS1 and NCAPG mRNA in gastric cancer cell lines.3.We used siRNA transduction to knock down NCAPG in OE-LGALS1-gastric cancer cells.We examined Galectin-1 and NCAPG expression levels in these gastric cancer cells by Western Blot and qPCR.Wound healing assay and transwell assay were used to detect changes in migration and invasion abilities of various types of gastric cancer cell lines.Results:1.The results of Western Blot and IHC showed that the expression of Galectin-1 and NCAPG in gastric cancer was significantly higher than that in normal gastric mucosa.2.The expression of Galectin-1 in gastric cancer tissues was significantly correlated with tumor diameter,pathological classification,depth of invasion,lymph node metastasis,and TNM stage.NCAPG expression in gastric cancer tissues was significantly associated with gender,tumor diameter,pathological classification,depth of invasion,lymph node metastasis,and TNM stage3.Univariate Cox regression analysis indicated that tumor diameter,pathological classification,depth of invasion,lymph node metastasis,TNM stage,and Galectin-1 and NCAPG expression were associated with Overall Survival(OS)in gastric cancer patients.Multivariate Cox regression analysis indicated that tumor diameter,TNM stage,and Galectin-1 and NCAPG expression were independent prognostic factors for all patient groups.4.Results from qPCR showed that the expression level of NCAPG mRNA in OELGALS1 gastric cancer cells were significantly higher than negative control cells and non-transducted cells.The result of Western Blot was consistent with qPCR.Therefore,Galectin-1 regulates NCAPG at mRNA and protein levels.5.mRNA expressions for LGALS1 and NCAPG were detected using qPCR.NCAPG knockdown in OE-LGALS1 gastric cancer cell lines significantly inhibited LGALS1 mRNA expression for gastric cancer cell.The result of Western Blot was consistent with qPCR.It is suggested that NCAPG can regulate the expression of Galectin-1 at mRNA and protein levels.6.The wound healing experiment demonstrated that LGALS1 over-expression enhanced gastric cancer cell migration.However,this was partly rescued by reinfected NCAPG-siRNA in OE-LGALS1 gastric cancer cells.Transwell assay showed significantly enhanced invasion ability in OE-LGALS1 gastric cancer cells.The cell invasion capability could be partly rescued by re-infected NCAPG-shRNA in OELGALS1 GC cells.Conclusion:1.The expression of Galectin-1 and NCAPG in gastric cancer was significantly higher than that in normal gastric mucosa.Combined detection of Galectin-1 and NCAPG has important predictive value for the prognosis of gastric cancer patients.2.Overexpression of LGALS1 in gastric cancer cells not only increase the expression of NCAPG at mRNA and protein levels,but also enhance the ability of migration and invasion of gastric cancer cells.Using siRNA to knock down the expression of NCAPG in overexpressed LGALS1 cell line,the migration and invasion abilities of gastric cancer cells were inhibited.The results showed that LGALS1 promoted the migration and invasion of gastric cancer cells by up-regulating the expression of NCAPG.LGALS1 and NCAPG are potential targets for reversing malignant biological behaviors such as metastasis and invasion of gastric cancer.