ABSTRACT
Objective To explore the expression and clinical significance of hypoxia-inducible factor 1α(HIF-1α)and glucose transporter-1(GLUT-1)in human lung adenocarcinoma cell line A549 and in elderly primary lung cancer tissue under hypoxia. Methods MTT assay was used to test the effect of CoCl2-induced hypoxia on the growth activity of lung adenocarcinoma cell line A549.Reverse transcription-polymerase chain reaction analysis(RT-PCR)and Western blot were used to determine the changes of HIF-1α and GLUT-1 in lung adenocarcinoma cell line A549 under hypoxia.The expressions of HIF-1α and GLUT-1 were detected by using immunohistochemical method and RT-PCR in 60 specimens of lung carcinoma and 26 benign lung tissues in elderly patients with pulmonary diseases.Their interrelations and their relationship with clinicopathologicaI characteristics of the tumors were analyzed. Results The growth activity of lung adenocarcinoma cell line A549 was increased under hypoxia.RT-PCR analysis indicated that the mRNA expressions of HIF-1α and GLUT-1 were 0.69±0.08,0.65±0.09 after hypoxia exposure for 24 hours,and 0.99±0.16,0.83±0.11 after hypoxia exposure for 48 hours,which were higher than those in control group (0.47±0.11,0.40±0.08,P＜0.01).The results from Western blot showed that the protein expressions of HIF-1α and GLUT-1 were 1.57±0.29,1.66±0.28 after hypoxia exposure for 24 hours,and 2.31±0.46,2.22±0.34 after hypoxia exposure for 48 hours,which were higher than those in control group(0.93±0.07,1.06±0.17,P＜0.01).In specimens of lung carcinoma,the positive expression rates of mRNA and proteins of HIF-1α and GLUT-1 were higher than those in benign lung tissues(all P＜0.01).Compared with the mRNA and protein levels of HIF-1a and GLUT-1 in lung carcinoma tissues of Ⅰ and Ⅱ stage,there were marked increases in Ⅲ and Ⅳ stage (all P＜0.05).The expressions of HIF-1α and GLUT-1 in lymph node metastasis group were higher than those in group without lymph node metastasis(all P＜0.05).There were positive correlations between the mRNA and protein expressions of HIF-1α and between the mRNA and protein expressions of GLUT-1(r1=0.527,r2=0.408,respectively,both P＜0.01). Conclusions CoCl2 can up-regulate the expressions of HIF-1α and GLUT-1 in lung adenocarcinoma cell line A549 by inducing hypoxia.The hypoxia-mediated effects on them have the potential to make lung cancer cells further grow and promote hypoxie tolerance.The overexpressions of HIF-1α and GLUT-1 are closely correlated with the progression of lung carcinoma.Combined detection of HIF-1α and GLUT-1 may be helpful for the diagnosis and prognosis prediction of primary lung cancer in elderly patients.