The Expression Of SCUBE2 And Its Molecular Mechanism Study In Colorectal Cancer

ObjectiveThe aim of this study is to investigate the expression of signal peptide-CUB-epidermal growth factor-like domain-containing protein 2(SCUBE2)in colorectal cancer,and further study the molecular mechanisms for colorectal cancer progression,which should lead to discover a new suppressor related to colorectal cancer.MethodsReal-time fluorogenic quantitative polymerase chain reaction(Real-time PCR)was conducted to quantify the expression level of SCUBE2 mRNA in the normal and cancerous tissues from 40 patients with colorectal cancer.Western blotting analysis and immunohistochemistry was conducted to test the expression level of SCUBE2 in paired normal and cancerous tissues from 4 or 120 patients with colorectal cancer,and study the correlation of SCUBE2 expression and clinicopathological features.Kaplan-Meier curves with a log rank test and Cox proportional hazards model analysis were applied for assess the association between SCUBE2 expression and patient survival,and calculated univariate and multivariate hazard ratios for the factors that influence patient survival time.In vitro,we combine using cell proliferation assay,plate colony formation assay,transwell chambers and apoptosis to explore the functions of SCUBE2 for inhibit colorectal cancer cells malignant behavior.The above methods were used to explore the expression of SCUBE2 and its molecular mechanism in colorectal cancer.ResultsThe results shows that among the 40 paired specimens,31(77.5%)showed at least a 2-fold increase in SCUBE2 mRNA levels in non-cancerous tissues as compared with those in the colorectal cancerous tissues.Western blotting analysis confirmed that SCUBE2 protein levels were significantly decreased in tumor tissue as compared with its paired normal mucosa,consistent with the results of real-time PCR.Immunohistochemistry studies on TMA showed that decreased expression of SCUBE2 was significantly correlated with American Joint Committee on cancer(AJCC)stage,depth of tumor invasion(P<0.001)and lymph node metastasis,distant metastasis and histologic differentiation(P<0.05).Kaplan-Meier curves with a log rank test and Cox proportional hazards model analysis indicated the patients with positive tumor SCUBE2 expression had a higher overall survival and disease-free survival rate than patients with negative SCUBE2 expression(P<0.001),and in the 37 recurrence cases,patients with negative SCUBE2 expression had a higher recurrence rate that patients with positive expression(Negative 75.68%,28/37 contrast to Positive 24.32%,9/37,P<0.001).Although SCUBE2 is not an independent prognosis factor,but it can still used for predict recurrence and prognosis after surgery in patients with colorectal cancer.Up-regulation of SCUBE2 significantly suppress the proliferation,colony formation,invasion and migration.ConclusionsWe identified SCUBE2 as a new colorectal cancer related suppressor gene.SCUBE2 was significantly down-regulated in colorectal cancer and could inhibit proliferation,invasion and migration for colorectal cancer cells.Explore the function of SCUBE2 and its molecular mechanism could promote new insights for predicting prognosis and using as a therapeutic target in colorectal cancer.