RESUMO
OBJECTIVE: To analyze the expression level of candidate tumor suppressor gene N-Myc downstream-regulated gene 2 (NDRG2) in human colon cancer. METHODS: Thirty samples of colon cancer tissues with matched normal colon tissues were collected. The NDRG2 mRNA level was detected by semi-quantitive RT-PCR and the NDRG2 protein level was examined by Western blot and immunohistochemistry. RESULTS: Twelve samples of colon cancer tissues had low NDRG2 mRNA level and low protein level. The positive rates of NDRG2 in normal tissues and the tumorous colon tissues were 90.0%(27/30) and 53.3%(16/30) by immunohistochemistry respectively. There was a significant difference between two groups (P<0.05). The NDRG2 expression was not correlated with age, sex, metastasis of lymph node, depth of infiltration, as well as the Dukes staging(P>0.05), while it was correlated to the histology grading. The positive rate of NDRG2 in the well- and moderate-differentiation group was higher than that in the poor-differentiation group(P<0.05). CONCLUSION: The expression of NDRG2 is low in some colon cancer tissues, which indicates that the low level of NDRG2 expression may be engaged in the development of colon cancer.
Assuntos
Neoplasias do Colo/metabolismo , Neoplasias do Colo/patologia , Proteínas Supressoras de Tumor/metabolismo , Western Blotting , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Supressoras de Tumor/genéticaRESUMO
AIM: To explore the induction of HepG2 cells by NDRG2 gene. METHODS: Human NDRG2 gene was obtained by RT-PCR. Sequence analysis proved that sequence of NDRG2 gene was correct. Then the gene was inserted into the eukaryotic expression vector pIRES2-EGFP and transfected into NDRG2 gene-negative HepG2 cells. The changes of cell morphology and structure were observed under light, fluorescence and transmission electron microscope, respectively. The variation of cell cycle was detected by flow cytometry. RESULTS: The NDRG2 gene had been obtained and its expression vector was constructed successfully. The NDRG2 gene-transfected HepG2 cells were shown a bad condition, structure damage, and a great number of died cells. The expression of target gene in cytoplasm of HepG2 cells was seen under fluorescence microscope. Flow cytometry analysis showed G1 phase arrest and apoptosis peak appeared.The typical manifestation of cell apoptosis could be observed under transmission electron microscope. CONCLUSION: NDRG2 gene can arrest HepG2 cell proliferation and induce their apoptosis.