Targeted inhibition of mTORC2 prevents osteosarcoma cell migration and promotes apoptosis

Wang,Xiaokai; Lai,Pinglin; Zhang,Zhongmin; Huang,Minjun; Wang,Liang; Yin,Min; Jin,Dadi; Zhou,Rongping; Bai,Xiaochun

doi:10.3892/or.2014.3182

Targeted inhibition of mTORC2 prevents osteosarcoma cell migration and promotes apoptosis

Authors:
- Xiaokai Wang
- Pinglin Lai
- Zhongmin Zhang
- Minjun Huang
- Liang Wang
- Min Yin
- Dadi Jin
- Rongping Zhou
- Xiaochun Bai
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Affiliations: Academy of Orthopedics of Guangdong Province, The Third Affiliated Hospital, Southern Medical University, Guangzhou, Guangdong 510630, P.R. China, Department of Cell Biology, School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China, Department of Orthopedics, Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China
Published online on: May 15, 2014 https://doi.org/10.3892/or.2014.3182
Pages: 382-388

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Abstract

Dysregulation of mammalian target of rapamycin (mTOR) signaling often occurs in many human malignant diseases, making it a potential target in the treatment of cancer. However, the effects of specifically targeted inhibition of mammalian target of rapamycin complex 2 (mTORC2) on osteosarcoma have not been reported. Three types of osteosarcoma cell lines (MG63/U2OS/Saos-2) were used in this study. Inhibition of mTORC2 was carried out by mTOR inhibitor PP242 and targeted siRNA. The anti-migration effect was evaluated through wound healing and Transwell assays. Osteosarcoma cells were either treated independently by inhibition of mTORC2 or in combination with cisplatin, and apoptosis was evaluated by staining with propidium iodide; PARP and caspase 7 expression levels were evaluated. Targeting of mTORC2 either by kinase inhibitor or rictor knockdown promoted cisplatin-induced apoptosis, but inhibition of mTORC1 either by rapamycin or raptor knockdown did not promote cisplatin-induced apoptosis. Furthermore, inhibition of mTORC2 but not mTORC1 effectively prevented osteosarcoma cell migration. These results suggest that agents that inhibit mTORC2 have advantages over mTORC1 inhibitors in the treatment of osteosarcoma. The present study provides a strong rationale for testing the use of mTORC1/2 inhibitors or the combination of mTORC1/2 inhibitors and cisplatin in the treatment of osteosarcoma.

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1	Biermann JS, Adkins D, Benjamin R, et al: Bone cancer. J Natl Compr Cancer Netw. 5:420–437. 2007.
2	Demetri GD, Baker LH, Benjamin RS, et al: Soft tissue sarcoma. J Natl Compr Cancer Netw. 5:364–399. 2007.PubMed/NCBI
3	Marina N, Gebhardt M, Teot L and Gorlick R: Biology and therapeutic advances for pediatric osteosarcoma. Oncologist. 9:422–441. 2004. View Article : Google Scholar : PubMed/NCBI
4	Patel SR, Vadhan-Raj S, Burgess MA, et al: Results of two consecutive trials of dose-intensive chemotherapy with doxorubicin and ifosfamide in patients with sarcomas. Am J Clin Oncol. 21:317–321. 1998. View Article : Google Scholar : PubMed/NCBI
5	Zoncu R, Efeyan A and Sabatini DM: mTOR: from growth signal integration to cancer, diabetes and ageing. Nat Rev Mol Cell Biol. 12:21–35. 2011. View Article : Google Scholar : PubMed/NCBI
6	Guertin DA and Sabatini DM: An expanding role for mTOR in cancer. Trends Mol Med. 11:353–361. 2005. View Article : Google Scholar : PubMed/NCBI
7	Fasolo A and Sessa C: Targeting mTOR pathways in human malignancies. Curr Pharm Des. 18:2766–2777. 2012. View Article : Google Scholar : PubMed/NCBI
8	Benjamin D, Colombi M, Moroni C and Hall MN: Rapamycin passes the torch: a new generation of mTOR inhibitors. Nat Rev Drug Discov. 10:868–880. 2011. View Article : Google Scholar : PubMed/NCBI
9	Houghton PJ: Everolimus. Clin Cancer Res. 16:1368–1372. 2010. View Article : Google Scholar : PubMed/NCBI
10	Guertin DA and Sabatini DM: The pharmacology of mTOR inhibition. Sci Signal. 2:pe242009. View Article : Google Scholar : PubMed/NCBI
11	Feldman ME, Apsel B, Uotila A, et al: Active-site inhibitors of mTOR target rapamycin-resistant outputs of mTORC1 and mTORC2. PLoS Biol. 7:e382009. View Article : Google Scholar : PubMed/NCBI
12	Yu K, Shi C, Toral-Barza L, et al: Beyond rapalog therapy: preclinical pharmacology and antitumor activity of WYE-125132, an ATP-competitive and specific inhibitor of mTORC1 and mTORC2. Cancer Res. 70:621–631. 2010. View Article : Google Scholar : PubMed/NCBI
13	Thoreen CC, Kang SA, Chang JW, et al: An ATP-competitive mammalian target of rapamycin inhibitor reveals rapamycin-resistant functions of mTORC1. J Biol Chem. 284:8023–8032. 2009. View Article : Google Scholar : PubMed/NCBI
14	Janes MR, Limon JJ, So L, et al: Effective and selective targeting of leukemia cells using a TORC1/2 kinase inhibitor. Nat Med. 16:205–213. 2010. View Article : Google Scholar : PubMed/NCBI
15	Schenone S, Brullo C, Musumeci F, et al: ATP-competitive inhibitors of mTOR: an update. Curr Med Chem. 18:2995–3014. 2011. View Article : Google Scholar : PubMed/NCBI
16	Shao H, Gao C, Tang H, et al: Dual targeting of mTORC1/C2 complexes enhances histone deacetylase inhibitor-mediated anti-tumor efficacy in primary HCC cancer in vitro and in vivo. J Hepatol. 56:176–183. 2012. View Article : Google Scholar : PubMed/NCBI
17	Zhang YJ, Duan Y and Zheng XF: Targeting the mTOR kinase domain: the second generation of mTOR inhibitors. Drug Discov Today. 16:325–331. 2011. View Article : Google Scholar : PubMed/NCBI
18	Bai X, Ma D, Liu A, et al: Rheb activates mTOR by antagonizing its endogenous inhibitor, FKBP38. Science. 318:977–980. 2007. View Article : Google Scholar : PubMed/NCBI
19	Li H, Lin J, Wang X, et al: Targeting of mTORC2 prevents cell migration and promotes apoptosis in breast cancer. Breast Cancer Res Treat. 134:1057–1066. 2012. View Article : Google Scholar : PubMed/NCBI
20	Chou TC and Talalay P: Quantitative analysis of dose-effect relationships: the combined effects of multiple drugs or enzyme inhibitors. Adv Enzyme Regul. 22:27–55. 1984. View Article : Google Scholar : PubMed/NCBI
21	Li DM and Feng YM: Signaling mechanism of cell adhesion molecules in breast cancer metastasis: potential therapeutic targets. Breast Cancer Res Treat. 128:7–21. 2011. View Article : Google Scholar : PubMed/NCBI
22	Song G, Ouyang G and Bao S: The activation of Akt/PKB signaling pathway and cell survival. J Cell Mol Med. 9:59–71. 2005. View Article : Google Scholar : PubMed/NCBI
23	Cohen SM and Lippard SJ: Cisplatin: from DNA damage to cancer chemotherapy. Prog Nucleic Acid Res Mol Biol. 67:93–130. 2001. View Article : Google Scholar : PubMed/NCBI
24	Thoreen CC and Sabatini DM: Rapamycin inhibits mTORC1, but not completely. Autophagy. 5:725–726. 2009. View Article : Google Scholar : PubMed/NCBI
25	Carew JS, Kelly KR and Nawrocki ST: Mechanisms of mTOR inhibitor resistance in cancer therapy. Target Oncol. 6:17–27. 2011. View Article : Google Scholar : PubMed/NCBI
26	Masri J, Bernath A, Martin J, et al: mTORC2 activity is elevated in gliomas and promotes growth and cell motility via overexpression of rictor. Cancer Res. 67:11712–11720. 2007. View Article : Google Scholar : PubMed/NCBI
27	Guertin DA, Stevens DM, Saitoh M, et al: mTOR complex 2 is required for the development of prostate cancer induced by Pten loss in mice. Cancer Cell. 15:148–159. 2009. View Article : Google Scholar : PubMed/NCBI
28	Shorning BY, Griffiths D and Clarke AR: Lkb1 and Pten synergise to suppress mTOR-mediated tumorigenesis and epithelial-mesenchymal transition in the mouse bladder. PLoS One. 6:e162092011. View Article : Google Scholar : PubMed/NCBI
29	Gulhati P, Bowen KA, Liu J, et al: mTORC1 and mTORC2 regulate EMT, motility, and metastasis of colorectal cancer via RhoA and Rac1 signaling pathways. Cancer Res. 71:3246–3256. 2011. View Article : Google Scholar : PubMed/NCBI
30	Inoki K, Mori H, Wang J, et al: mTORC1 activation in podocytes is a critical step in the development of diabetic nephropathy in mice. J Clin Invest. 121:2181–2196. 2011. View Article : Google Scholar : PubMed/NCBI
31	Proud CG: mTOR signalling in health and disease. Biochem Soc Trans. 39:431–436. 2011. View Article : Google Scholar : PubMed/NCBI
32	Sparks CA and Guertin DA: Targeting mTOR: prospects for mTOR complex 2 inhibitors in cancer therapy. Oncogene. 29:3733–3744. 2010. View Article : Google Scholar : PubMed/NCBI