Estradiol and mTORC2 cooperate to enhance prostaglandin biosynthesis and tumorigenesis in TSC2-deficient LAM cells

C Li, PS Lee, Y Sun, X Gu, E Zhang, Y Guo… - Journal of Experimental …, 2014 - rupress.org
C Li, PS Lee, Y Sun, X Gu, E Zhang, Y Guo, CL Wu, N Auricchio, C Priolo, J Li, A Csibi
Journal of Experimental Medicine, 2014rupress.org
Lymphangioleiomyomatosis (LAM) is a progressive neoplastic disorder that leads to lung
destruction and respiratory failure primarily in women. LAM is typically caused by tuberous
sclerosis complex 2 (TSC2) mutations resulting in mTORC1 activation in proliferative smooth
muscle–like cells in the lung. The female predominance of LAM suggests that estradiol
contributes to disease development. Metabolomic profiling identified an estradiol-enhanced
prostaglandin biosynthesis signature in Tsc2-deficient (TSC−) cells, both in vitro and in vivo …
Lymphangioleiomyomatosis (LAM) is a progressive neoplastic disorder that leads to lung destruction and respiratory failure primarily in women. LAM is typically caused by tuberous sclerosis complex 2 (TSC2) mutations resulting in mTORC1 activation in proliferative smooth muscle–like cells in the lung. The female predominance of LAM suggests that estradiol contributes to disease development. Metabolomic profiling identified an estradiol-enhanced prostaglandin biosynthesis signature in Tsc2-deficient (TSC) cells, both in vitro and in vivo. Estradiol increased the expression of cyclooxygenase-2 (COX-2), a rate-limiting enzyme in prostaglandin biosynthesis, which was also increased at baseline in TSC-deficient cells and was not affected by rapamycin treatment. However, both Torin 1 treatment and Rictor knockdown led to reduced COX-2 expression and phospho-Akt-S473. Prostaglandin production was also increased in TSC-deficient cells. In preclinical models, both Celecoxib and aspirin reduced tumor development. LAM patients had significantly higher serum prostaglandin levels than healthy women. 15-epi-lipoxin-A4 was identified in exhaled breath condensate from LAM subjects and was increased by aspirin treatment, indicative of functional COX-2 expression in the LAM airway. In vitro, 15-epi-lipoxin-A4 reduced the proliferation of LAM patient–derived cells in a dose-dependent manner. Targeting COX-2 and prostaglandin pathways may have therapeutic value in LAM and TSC-related diseases, and possibly in other conditions associated with mTOR hyperactivation.
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