The down-regulation of Notch1 inhibits the invasion and migration of hepatocellular carcinoma cells by inactivating the cyclooxygenase-2/Snail/E-cadherin pathway in vitro.
BACKGROUND
The Notch signaling pathway plays an important role in cancer, but the mechanism by which Notch1 participates in invasion and migration of hepatocellular carcinoma (HCC) cells is unclear.


OBJECTIVE
Our purpose is to confirm the anti-invasion and anti-migration effects of the down-regulation of Notch1 in HCC cells.


METHODS
The invasion and migration capacities of HCC cells were detected with Transwell cell culture chambers. The expressions of Notch1, Notch1 intracellular domain (N1ICD), E-cadherin, Snail, and cyclooxygenase-2 (COX-2) were analyzed by RT-PCR and/or western blotting. Notch1 and Snail were down-regulated by RNA interference, and COX-2 was inhibited by NS-398. Cell apoptosis was analyzed by MTT and flow cytometry.


RESULTS
In HCC cells, Snail, Notch1, and COX-2 were up-regulated, and E-cadherin was down-regulated in mRNA and/or protein levels. The down-regulation of Snail or Notch1 or the inhibition of COX-2, respectively, can increase the mRNA and protein expressions of E-cadherin and decrease the invasion and migration capabilities of HCC cell. Down-regulated Notch1 or inhibited COX-2 can reduce the mRNA and protein expressions of Snail. The down-regulation of Notch1 can also reduce the protein expression of COX-2. However, exogenous PGE2 can reverse the role of down-regulated Notch1. The results of MTT and flow cytometry showed that down-regulated Notch1 did not affect HCC cell viability.


CONCLUSIONS
Down-regulated Notch1 may be an effective approach to inactivating Snail/E-cadherin by regulating COX-2, which results in inhibiting the invasion and migration of HCC cells. The inhibitory effects of down-regulated Notch1 on cell invasion and migration were independent of apoptosis.
Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, Shannxi, People's Republic of China.
Liang
L
Zhou
De-Sheng
DS
Wang
Qing-Jun
QJ
Li
Wei
W
Sun
Yong
Y
Zhang
Ke-Feng
KF
Dou
D015820:Cadherins / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D002465:Cell Movement; D051546:Cyclooxygenase 2 / Q000378:metabolism; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D056945:Hep G2 Cells; D006801:Humans; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D009361:Neoplasm Invasiveness; D051881:Receptor, Notch1 / Q000378:metabolism*; D015398:Signal Transduction; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000378:metabolism
D015820:Cadherins; C497761:NOTCH1 protein, human; D051881:Receptor, Notch1; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human