[Mechanism of antisense epidermal growth factor receptor cDNA in growth suppression of glioblastomas cells].
OBJECTIVE
To study the mechanism of antisense epidermal growth factor receptor cDNA in growth suppression of glioblastomas cells.


METHODS
Glioblastoma U87MG cells, which over-express epidermal growth factor receptor (EGFR), were transfected with antisense-EGFR constructs. Several clones with stable expression of lower or undetectable levels of EGFR protein were obtained. The effect of antisense-EGFR on cell differentiation was studied using morphological evaluation and western blotting analysis of glial fibrillary acidic protein (GFAP) expression. The effect of antisense-EGFR on cell cycle was studied by flow cytometry and immunohistochemical analysis of p53, Rb, p16 and CDK4 expressions. The effect of antisense-EGFR on telomerase activity was studied by telomeric repeat amplification protocol (TRAP) assay.


RESULTS
U87MG cells that were transfected with antisense-EGFR constructs had smaller cell bodies and longer processes, and expressed higher level of GFAP compared with that of the control cells. Flow cytometric analysis showed that the proportion of cells in G(0)/G(1) phases of the cell cycle in the antisense EGFR cDNA transfected clones increased significantly when compared with control cells, whereas the proportion of cells in S phase decreased markedly. In addition, immunohistochemical analysis showed that the expression of wild-type p53 was significantly increased in the antisense-EGFR cDNA transfected clones, whereas the expressions of Rb, p16 and CDK4 were not altered. TRAP assay revealed that telomerase activity in the antisense-EGFR clones was significantly decreased.


CONCLUSIONS
Antisense-EGFR transfection inhibits U87MG cell growth by inducing cell differentiation and p53 expression, G(1) cell cycle arrest and inhibition of telomerase activity.
Tian
Xin-xia
XX
Department of Pathology, Health Science Center, Peking University, Beijing 100083, China. tianxinxia@yahoo.com
Ng
Ho-keung
HK
Pang
Chung-sean
CS
Zheng
Jie
J
Du
Juan
J
D045744:Cell Line, Tumor; D016373:DNA, Antisense / Q000627:therapeutic use*; D018076:DNA, Complementary / Q000627:therapeutic use*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000235:genetics; D005434:Flow Cytometry; D005909:Glioblastoma / Q000737:chemistry / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D016160:Retinoblastoma Protein / Q000032:analysis; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
D016373:DNA, Antisense; D018076:DNA, Complementary; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D066246:ErbB Receptors