Oncogenic effects of urotensin-II in cells lacking tuberous sclerosis complex-2
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Alexander A. Goldberg1,2, Kwang-Bo Joung1,2, Asma Mansuri1,2, Yujin Kang1,2, Raquel Echavarria1,2, Ljiljana Nikolajev3,4, Yang Sun5, Jane J. Yu5, Stephane A. Laporte3,4, Adel Schwertani6, Arnold S. Kristof1,2
1Meakins-Christie Laboratories, Translational Research in Respiratory Diseases Program, Montreal, Quebec, Canada
2Department of Critical Care Medicine, McGill University Health Centre Research Institute, Montreal, Quebec, Canada
3Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada
4Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
5College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
6Division of Cardiology, Montreal General Hospital, Montreal, Quebec, Canada
Arnold S. Kristof, email: [email protected]
Keywords: TSC2, mTOR, urotensin, lymphangioleiomyomatosis, angiomyolipoma
Received: May 20, 2016 Accepted: July 01, 2016 Published: July 21, 2016
Lymphangioleiomyomatosis (LAM) is a destructive lung disease that can arise sporadically or in adults suffering from the tumor syndrome tuberous sclerosis complex (TSC). Microscopic tumors (‘LAM nodules’) in the lung interstitium arise from lymphatic invasion and metastasis. These consist of smooth muscle-like cells (LAM cells) that exhibit markers of neural crest differentiation and loss of the tumor suppressor protein ‘tuberous sclerosis complex-2’ (TSC2). Consistent with a neural phenotype, expression of the neuropeptide urotensin-II and its receptor was detected in LAM nodules. We hypothesized that loss of TSC2 sensitizes cells to the oncogenic effects of urotensin-II. TSC2-deficient Eker rat uterine leiomyoma ELT3 cells were stably transfected with empty vector or plasmid for the expression of TSC2. Urotensin-II increased cell viability and proliferation in TSC2-deficient cells, but not in TSC2-reconstituted cells. When exposed to urotensin-II, TSC2-deficient cells exhibited greater migration, anchorage-independent cell growth, and matrix invasion. The effects of urotensin-II on TSC2-deficient cells were blocked by the urotensin receptor antagonist SB657510, and accompanied by activation of Erk mitogen-activated protein kinase and focal adhesion kinase. Urotensin-II-induced proliferation and migration were reproduced in TSC2-deficient human angiomyolipoma cells, but not in those stably expressing TSC2. In a mouse xenograft model, SB657510 blocked the growth of established ELT3 tumors, reduced the number of circulating tumor cells, and attenuated the production of VEGF-D, a clinical biomarker of LAM. Urotensin receptor antagonists may be selective therapeutic agents for the treatment of LAM or other neural crest-derived neoplasms featuring loss of TSC2 or increased expression of the urotensin receptor.
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