beta-catenin regulates multiple steps of RNA metabolism as revealed by the RNA aptamer in colon cancer cells.
Nuclear beta-catenin forms a transcription complex with TCF-4, which is implicated in colon cancer development and progression. Recently, we and others have shown that beta-catenin could be a regulator of RNA splicing and it also stabilizes the cyclooxygenase-2 (COX-2) mRNA. Here, we further explored the role of beta-catenin in the RNA metabolism in colon cancer cells. To specifically modulate the subcellular functions of beta-catenin, we expressed the RNA aptamer in the form of RNA intramers with unique cellular localizations. The nucleus-expressed RNA intramer proved to be effective in reducing the protein-protein interaction between beta-catenin and TCF-4, thus shown to be a specific regulator of beta-catenin-activated transcription. It could also regulate the alternative splicing of E1A minigene in diverse colon cancer cell lines. In addition, we tested whether beta-catenin could stabilize any other mRNAs and found that cyclin D1 mRNA was also bound and stabilized by beta-catenin. Significantly, the cytoplasm-expressed RNA intramer reverted the beta-catenin-induced COX-2 and cyclin D1 mRNA stabilization. We show here that beta-catenin regulated multiple steps of RNA metabolism in colon cancer cells and might be the protein factor coordinating RNA metabolism. We suggest that the RNA intramers could provide useful ways for inhibiting beta-catenin-mediated transcription and RNA metabolism, which might further enhance the antitumorigenic effects of these molecules in colon cancer cells.
Lee
Hee Kyu
HK
Department of Molecular Biology, BK21 Graduate Program for RNA Biology, Institute of Nanosensor and Biotechnology, Dankook University Seoul, Republic of Korea.
Kwak
Ho Yoon
HY
Hur
Jung
J
Kim
In Ae
IA
Yang
Ji Sun
JS
Park
Min Woo
MW
Yu
Jaehoon
J
Jeong
Sunjoo
S
D000230:Adenocarcinoma / Q000235:genetics* / Q000378:metabolism; D017398:Alternative Splicing; D000818:Animals; D052157:Aptamers, Nucleotide / Q000235:genetics / Q000378:metabolism*; D003110:Colonic Neoplasms / Q000235:genetics* / Q000378:metabolism; D019938:Cyclin D1 / Q000096:biosynthesis / Q000235:genetics; D051546:Cyclooxygenase 2 / Q000096:biosynthesis / Q000235:genetics; D045325:HCT116 Cells; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism*; D051820:TCF Transcription Factors / Q000378:metabolism; D058118:Transcription Factor 7-Like 2 Protein; D051176:beta Catenin / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
D052157:Aptamers, Nucleotide; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D051820:TCF Transcription Factors; C544894:TCF7L2 protein, human; C544895:Tcf7l2 protein, mouse; D058118:Transcription Factor 7-Like 2 Protein; D051176:beta Catenin; D019938:Cyclin D1; D051546:Cyclooxygenase 2