Relationship Between Expression Of GLUT-1 In Colorectal Cancer And Clinicopathological Features And Its Role In Colon Cancer Cells

Background&Objective:When many solid tumors grow to a certain volume,the oxygen demand exceeds the supply of their own vessels,which will cause a micro-environment of local hypoxia.Tumors,through various mechanisms that regulate certain key genes to adapt to this environment,promote a more aggressive and proliferative tumor phenotype.Among them,hypoxia-inducible factor 1(HIF-1)is one of the key factors regulating the hypoxia response of cells through transcription.In the HIF-1 mediated pathway,various hypoxia-associated factors are activated,such as glucose transporter-1(GLUT-1),which converts tumor cell metabolism to anaerobic glycolysis and promotes angiogenesis.Increase oxygen supply to help cells survive in an oxygen-deficient microenvironment.More studies have shown that the expression of GLUT-1 protein in human colorectal cancer tissues is different from that in normal tissues.This study was to investigate the relationship between GLUT-1 protein and clinical features of colorectal cancer and its proliferation and migration in tumor cells and the role of apoptosis.In the first part,we used immunohistochemistry to detect the expression and clinical pathological significance of GLUT-1 in colorectal cancer specimens and adjacent tissues,and to explore its effect on patient prognosis.In the second part,the expression of GLUT-1 protein in human colon cancer cell line was knocked down by lentiviral transfection,and the proliferation,migration and apoptosis of tumor cells were observed.Methods:1.We collected 95 cases of primary colorectal cancer tissue and normal tissues corresponding adjacent cancerous(>5cm)from January 2014 to June 2015 in Jiangsu Subei People's Hospital of Yangzhou City;We used immunohistochemstry to detect the expression of GLUT-1 protein in adjacent tissues and cancer tissues.The survival curve was drawn by Kaplan-Meier and analyzed by Long-rank test.The Cox regression model was used to analyze the prognosis of patients with colorectal cancer by univariate and multivariate analysis.2.Human colon cancer cells HCT116 and HT29 cell lines were transfected with lentivirus to knock down GLUT-1 expression;Western blot was used to detect the expression of cell protein;MTT assay was used to detect the effect of knockdown of GLUT-1 on cell proliferation.Cell scratch assay was used to detect the migration of HCT116 cells;AnnexinV-FITC/PI double staining was used to detect apoptosis.Results:1.GLUT-1 expression in tumor tissues(69/95,72.6%)was higher than that in adjacent tissues(10/95,10.5%)and the difference was statistically significant(?2=37.7,P<0.05);The expression of GLUT-1 in colorectal cancer tissues was significantly different from lymph node metastasis(?2=6.2,P<0.05)and TNM stage(?2=13.5,P<0.05),but was no difference with age,sex,tumor size and differentiation(P>0.05).There was no significant difference in the overall survival of patients with GLUT-1 positive and negative expression(x2=2.3,P=0.13),but in TNM stage III-IV,GLUT The prognosis of protein positive patients was lower than that of GLUT-1 negative patients(?2=4.009,P=0.045);in the univariate analysis,tumor lymph node metastasis(HR=6.5,95%CI=2.5-17.1,P<0.001),TNM staging(HR=5.8,95%CI=2.2-15.3,P<0.001)was a risk factor affecting patient survival.In multivariate Cox regression analysis,only lymph node metastasis(P<0.05)regarded as independent risk factors for prognosis.2.The proliferation of human colon cancer cells HCT116 and HT29 cells was detected by MTT assay after knockdown of GLUT-1 by lentivirus.The cells were significantly inhibited at 24h,48h and 72h.The cell scratch assay showed that HCT116 cells migrated at 24h and 36h was inhibited;the apoptosis rate of HCT116 cells transfected with GLUT1 was significantly higher than that of the control group by flow cytometry.Conclusion:1.GLUT-1 expression in cancer tissues is higher than that in adjacent tissues,and has a higher expression rate in lymph node metastasis and TNM ?-? stage patients,suggesting that GLUT-1 may be involved in tumor metastasis and progression;In the univariate analysis of the overall survival rate of patients with colorectal cancer,tumor lymph node metastasis and TNM staging are the main prognostic factors affecting the prognosis of patients;Multivariate analysis suggests that tumor lymph node metastasis is the most important prognostic factor;In colorectal cancer TNM III-IV,patients with GLUT-1 negative expression had a better prognosis than patients with positive expression,and GLUT-1 may be used as predictors for postoperative colorectal cancer patients.2.The proliferation and migration of human colon cancer cell lines with low GLUT-1 expression were significantly inhibited,and apoptosis was promoted.