AU-1 from Agavaceae plants causes transient increase in p21/Cip1 expression in renal adenocarcinoma ACHN cells in an miR-34-dependent manner
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Here, we show that AU-1, spirostanol saponin isolated from Agavaceae plants, causes a transient increase in cyclin-dependent kinase inhibitor (CDKI) p21/Cip1 through the upregulation of miRNAs, miR-34 and miR-21. AU-1 stimulated p21/Cip1 expression without exerting cytotoxicity against different types of carcinoma cell lines. In renal adenocarcinoma ACHN cells, AU-1 transiently elevated the expression level of p21/Cip1 protein without marked increases in p21/Cip1 mRNA levels. Rapid and transient increases in miR-34 and miR-21, both of which are known to upregulate p21/Cip1, were observed in AU-1-treated cells. Inhibitor for miR-34 and for miR-21 significantly blocked the AU-1-caused increase in p21/Cip1, indicating that elevation of p21/Cip1 protein by AU-1 is dependent on these microRNAs. We further clarified that NAD-dependent deacetylase SIRT1, a direct target of miR-34, is decreased by the treatment with AU-1. Furthermore, we found that SIRT1-knockdown increases p21/Cip1 protein levels in an miR-21-dependent manner. On the other hand, ectopic expression of p21/Cip1 resulted in the lowered expression of miR-34 and miR-21, suggesting that reciprocal regulation exists between p21/Cip1 and these miRNAs. We propose that the following feedback network composed of miR-34/SIRT1/miR-21/p21 is triggered by the treatment with AU-1: in cells treated with AU-1, transient elevation of miR-34 leads to the downregulation of SIRT1, thereby miR-21 is freed from SIRT1-dependent suppression. Then, elevated miR-21 upregulates p21/Cip1 protein, followed by the suppression of miR-34 expression.
KeywordsAgave utahensis p21/Cip1 miR-34 miR-21 SIRT1
We thank Ken Ando, Toshiyuki Oshima, and Harutaka Ichikawa for their helpful advice and discussions. This work was supported, in part, by a grant from the Japan Private School Promotion Foundation.
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- 1.Fujino T, Takeuchi A, Maruko-Ohtake A, Ohtake Y, Satoh J, Kobayashi T, Tanaka T, Ito H, Sakamaki R, Kashimura R, Ando K, Nishimaki-Mogami T, Ohkubo Y, Kitamura N, Sato R, Kikugawa K, Hayakawa M (2012) Critical role of farnesoid X receptor for hepatocellular carcinoma cell proliferation. J Biochem 152:577–586CrossRefPubMedGoogle Scholar
- 2.Fujino T, Maruko-Ohtake A, Ohtake Y, Kobayashi T, Ando K, Takeuchi A, Ohkubo Y, Hayakawa M (2015) Farnesoid X receptor knockdown provides significant growth inhibition in hepatocellular carcinoma cells while it does not interfere with the proliferation of primary human hepatocyte-derived cells. J Toxicol Sci 40:501–508CrossRefPubMedGoogle Scholar
- 3.Fujino T, Kuroda M, Matsuo Y, Kubo S, Tamura C, Sakamoto N, Mimaki Y, Hayakawa M (2015) Cardenolide glycosides from the seeds of Digitalis purpurea exhibit carcinoma-specific cytotoxicity toward renal adenocarcinoma and hepatocellular carcinoma cells. Biosci Biotechnol Biochem 79:177–184CrossRefPubMedGoogle Scholar
- 7.Dellago H, Preschitz-Kammerhofer B, Terlecki-Zaniewicz L, Schreiner C, Fortschegger K, Chang MW, Hackl M, Monteforte R, Kühnel H, Schosserer M, Gruber F, Tschachler E, Scheideler M, Grillari-Voglauer R, Grillari J, Wieser M (2013) High levels of oncomiR-21 contribute to the senescence-induced growth arrest in normal human cells and its knock-down increases the replicative lifespan. Aging Cell 12:446–458CrossRefPubMedPubMedCentralGoogle Scholar