Objective: Celastrol, a plant triterpene, has anticancer effects by increase of apoptosis. In the present study, the mechanism of celastrol on gastric cancer cell apoptosis was examined. Methods: The effect of celastrol on PI3K/Akt and the NF-κB signaling pathway was evaluated with Western blot and luciferase reporter assay. miR-21 expression was determined using real-time PCR. miR-21 inhibitor and miR-21 mimic were used to downregulate and upregulate miR-21 expression, respectively. Results: It was identified that celastrol was capable of inducing apoptosis of gastric cancer cells, which was mediated via inhibiting the activation of PI3K/Akt and NF-κB. A strong activator of Akt, IGF-1 restored NF-κB activity in cells treated with celastrol. Celastrol could also significantly suppress miR-21 expression. Furthermore, miR-21 inhibitor could decrease phospho-Akt expression and NF-κB activity. Notably, upregulation of miR-21 expression can increase PI3K/Akt and NF-κB activity and decrease apoptosis of gastric cancer cells treated with celastrol, which could be reversed by PI3K inhibitor. Conclusions: Our data revealed that the effect of celastrol on apoptosis was due to miR-21 inhibiting the PI3K/Akt-dependent NF-κB pathway.

Keywords:
Gastric cancer, Celastrol, miR-21 inhibitor, PI3K/Akt-NF-κB signaling pathway, Apoptosis
1.
Leung WK, Wu MS, Kakugawa Y, Kim JJ, Yeoh KG, Goh KL, Wu KC, Wu DC, Sollano J, Kachintorn U, Gotoda T, Lin JT, You WC, Ng EK, Sung JJ: Screening for gastric cancer in Asia: current evidence and practice. Lancet Oncol 2008;9:279-287.
2.
Li YL, Li J, Yan CY, Lai ZF, Hu GJ: Chinese medicine single-walled carbon nanotube targeting compound for antitumor therapy: a feasible way? Chin J Integr Med, E-pub ahead of print.
3.
Morita T: Celastrol: a new therapeutic potential of traditional Chinese medicine. Am J Hypertens 2010;23:821.
4.
Kannaiyan R, Manu KA, Chen L, Li F, Rajendran P, Subramaniam A, Lam P, Kumar AP, Sethi G: Celastrol inhibits tumor cell proliferation and promotes apoptosis through the activation of c-Jun N-terminal kinase and suppression of PI3 K/Akt signaling pathways. Apoptosis 2011;16:1028-1041.
5.
Winter J, Jung S, Keller S, Gregory RI, Diederich S: Many roads to maturity: microRNA biogenesis pathways and their regulation. Nat Cell Biol 2009;11:228-234.
6.
Osawa S, Shimada Y, Sekine S, Okumura T, Nagata T, Fukuoka J, Tsukada K: MicroRNA profiling of gastric cancer patients from formalin-fixed paraffin-embedded samples. Oncol Lett 2011;2:613-619.
7.
Cui L, Zhang X, Ye G, Zheng T, Song H, Deng H, Xiao B, Xia T, Yu X, Le Y, Guo J: Gastric juice microRNAs as potential biomarkers for the screening of gastric cancer. Cancer 2013;119:1618-1626.
8.
Xu L, Dai WQ, Xu XF, Wang F, He L, Guo CY: Effects of multiple-target anti-microRNA antisense oligodeoxyribonucleotides on proliferation and migration of gastric cancer cells. Asian Pac J Cancer Prev 2012;13:3203-3207.
9.
Zhang BG, Li JF, Yu BQ, Zhu ZG, Liu BY, Yan M: microRNA-21 promotes tumor proliferation and invasion in gastric cancer by targeting PTEN. Oncol Rep 2012;27:1019-1026.
10.
Almhanna K, Strosberg J, Malafa M: Targeting AKT protein kinase in gastric cancer. Anticancer Res 2011;31:4387-4392.
11.
Baud V, Karin M: Is NF-κB a good target for cancer therapy? Hopes and pitfalls. Nat Rev Drug Discov 2009;8:33-40.
12.
Dutta J, Fan Y, Gupta N, Fan G, Gélinas C: Current insights into the regulation of programmed cell death by NF-κB. Oncogene 2006;25:6800-6816.
13.
Guo C, Gasparian AV, Zhuang Z, Bosykh DA, Komar AA, Gudkov AV, Gurova KV: 9-Aminoacridine-based anticancer drugs target the PI3K/AKT/mTOR, NF-κB and p53 pathways. Oncogene 2009;28:1151-1161.
14.
Sha M, Ye J, Zhang LX, Luan ZY, Chen YB: Celastrol induces apoptosis of gastric cancer cells by miR-146a inhibition of NF-κB activity. Cancer Cell Int 2013;13:50.
15.
Ma T, Zhu ZG, Ji YB, Zhang Y, Yu YY, Liu BY, Yin HR, Lin YZ: Correlation of thymidylate synthase, thymidine phosphorylase and dihydropyrimidine dehydrogenase with sensitivity of gastrointestinal cancer cells to 5-fluorouracil and 5-fluoro-2′-deoxyuridine. World J Gastroenterol 2004;10:172-176.
16.
Vermes I, Haanen C, Reutelingsperger C: Flow cytometry of apoptotic cell death. J Immunol Methods 2000;243:167-190.
17.
Zhou LL, Lin ZX, Fung KP, Cheng CH, Che CT, Zhao M, Wu SH, Zuo Z: Celastrol-induced apoptosis in human HaCaT keratinocytes involves the inhibition of NF-κB activity. Eur J Pharmacol 2011;670:399-408.
18.
Wang WB, Feng LX, Yue QX, Wu WY, Guan SH, Jiang BH, Yang M, Liu X, Guo DA: Paraptosis accompanied by autophagy and apoptosis was induced by celastrol, a natural compound with influence on proteasome, ER stress and Hsp90. J Cell Physiol 2012;227:2196-2206.
19.
Riedl SJ, Shi Y: Molecular mechanisms of caspase regulation during apoptosis. Nat Rev Mol Cell Biol 2004;5:897-907.
20.
Kannaiyan R, Shanmugam MK, Sethi G: Molecular targets of celastrol derived from Thunder of God Vine: potential role in the treatment of inflammatory disorders and cancer. Cancer Lett 2011;303:9-20.
21.
Buscaglia LE, Li Y: Apoptosis and the target genes of microRNA-21. Chin J Cancer 2011;30:371-380.
22.
Chan SH, Wu CW, Li AF, Chi CW, Lin WC: miR-21 microRNA expression in human gastric carcinomas and its clinical association. Anticancer Res 2008;28:907-911.
23.
Rasul A, Ding C, Li X, Khan M, Yi F, Ali M, Ma T: Dracorhodin perchlorate inhibits PI3K/Akt and NF-κB activation, up-regulates the expression of p53, and enhances apoptosis. Apoptosis 2012;17:1104-1119.
24.
Shen HM, Tergaonkar V: NF-κB signaling in carcinogenesis and as a potential molecular target for cancer therapy. Apoptosis 2009;14:348-363.
25.
Tozawa K, Sagawa M, Kizaki M: Quinone methide tripterine, celastrol, induces apoptosis in human myeloma cells via NF-κB pathway. Int J Oncol 2011;39:1117-1122.
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2014
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