Targeting of COX-2 expression by recombinant adenovirus shRNA attenuates the malignant biological behavior of breast cancer cells.
BACKGROUND
Cyclooxygenase-2 (COX-2), considered to have tumor-promoting potential, is highly expressed in a variety of tumors, including breast cancer. Since the functions and action mechanisms of COX-2 in breast cancer have not been fully elucidated, in the present study, the effects of target inhibiting COX-2 with recombinant adenovirus Ad-COX-2-shRNA on malignant biological behavior were investigated in representative cell lines.


METHODS
Breast cancer MDA-MB-231 and MCF-7 cells were transfected with Ad-COX-2-shRNA and COX-2 expression was tested by RT-PCR and Western blotting. Changes in proliferation, apoptosis and invasion of breast cancer cells were detected with various assays including MTT, colony forming, flowcytometry and Transwell invasion tests. The expression of related proteins involved in the cell cycle, apoptosis, invasion and signaling pathways was assessed by Western blotting.


RESULTS
COX-2 expression was significantly reduced in both breast cancer cell lines infected with Ad-COX-2-shRNA, with obvious inhibition of proliferation, colony forming rate, G2/M phase passage and invasion, as well as induction of apoptosis, in MDA-MB-231 and MCF-7 cells, respectively. At the same time, proteins related to the cell cycle, anti-apoptosis and invasion were significantly downregulated. In addition, c-myc expression and phosphorylation activation of Wnt/β-catenin and p38MAPK pathways were reduced by the Ad-COX-2-shRNA.


CONCLUSIONS
COX-2 expression is associated with proliferation, apoptosis and invasion of breast cancer cells, and its mechanisms of action involve regulating expression of c-myc through the p38MAPK and Wnt/β-catenin pathways.
Department of Ultrasonic Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing Medical University, Chongqing, China E-mail : hxlcyfyy@163.com.
Bo
B
Tu
Ting-Ting
TT
Ma
Xiao-Qiong
XQ
Peng
Qin
Q
Wang
Hong
H
Yang
Xiao-Ling
XL
Huang
D000256:Adenoviridae / Q000235:genetics*; D017209:Apoptosis; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D002453:Cell Cycle; D049109:Cell Proliferation; D051546:Cyclooxygenase 2 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D009361:Neoplasm Invasiveness; D010766:Phosphorylation; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014407:Tumor Cells, Cultured
D012333:RNA, Messenger; D034741:RNA, Small Interfering; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human