Carcinogenesis Advance Access originally published online on March 26, 2007
Carcinogenesis 2007 28(8):1622-1628; doi:10.1093/carcin/bgm064
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Mechanisms of growth arrest by zinc ribbon domain-containing 1 in gastric cancer cells
1 State Key Laboratory of Cancer Biology and Institute of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032 Shaanxi Province, China
2 Department of Thoracic Surgery, Institute of Surgery Research, Daping Hospital. Third Military Medical University, Chongqing, China
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Previous studies by our laboratory indicated that zinc ribbon domain-containing 1 (ZNRD1) suppressed the growth of gastric cancer cells with a G1 cell cycle arrest. However, the precise molecular mechanism underlying the growth-inhibitory effect of ZNRD1 remained fragmentary. In the present study, we have demonstrated that ZNRD1 could significantly inhibit the in vitro and in vivo growth of gastric cell line MKN28. Human cDNA microarray, reverse transcription–polymerase chain reaction and western blot analyses were used to identify differentially expressed cell cycle-related genes in MKN28 cells over-expressing ZNRD1. ZNRD1-induced growth suppression was found at least partially to regulate various proteins and signaling pathways controlling G1 to S progression, including inhibition of cyclin D1 and CDK4, up-regulation of p21CIP1/WAF1 and p27Kip1 and acceleration of pRb dephosphorylation. Furthermore, ZNRD1 significantly inhibited the transcriptional activity of cyclin D1. p27Kip1 might play a pivotal role in ZNRD1-induced cell cycle arrest because the p27Kip1 anti-sense could block the cytostatic effects of ZNRD1. Moreover, ZNRD1 suppressed Skp2 expression via an increase in the protein instability, and induced significant decrease in cyclin E–CDK2 kinase activity. In addition, ZNRD1 could reduce tumor microvessel densities through inhibition of VEGF. Taken together, these results suggested that ZNRD1 might inhibit cell growth by targeting cell cycle-related genes and reducing tumor angiogenesis.
Abbreviations: FCM, flow cytometry; RT–PCR, reverse transcription–polymerase chain reaction; ZNRD1, zinc ribbon domain-containing 1
These authors contributed equally to this work. Received January 10, 2007; revised February 24, 2007; accepted March 14, 2007.