[PDF][PDF] TSC2 regulates VEGF through mTOR-dependent and-independent pathways

JB Brugarolas, F Vazquez, A Reddy, WR Sellers… - Cancer cell, 2003 - cell.com
JB Brugarolas, F Vazquez, A Reddy, WR Sellers, WG Kaelin
Cancer cell, 2003cell.com
Inactivation of the TSC2 tumor suppressor protein causes tuberous sclerosis complex (TSC),
a disease characterized by highly vascular tumors. TSC2 has multiple functions including
inhibition of mTOR (mammalian target of Rapamycin). We found that TSC2 regulates VEGF
through mTOR-dependent and-independent pathways. TSC2 loss results in the
accumulation of HIF-1α and increased expression of HIF-responsive genes including VEGF.
Wild-type TSC2, but not a disease-associated TSC2 mutant, downregulates HIF. Rapamycin …
Abstract
Inactivation of the TSC2 tumor suppressor protein causes tuberous sclerosis complex (TSC), a disease characterized by highly vascular tumors. TSC2 has multiple functions including inhibition of mTOR (mammalian target of Rapamycin). We found that TSC2 regulates VEGF through mTOR-dependent and -independent pathways. TSC2 loss results in the accumulation of HIF-1α and increased expression of HIF-responsive genes including VEGF. Wild-type TSC2, but not a disease-associated TSC2 mutant, downregulates HIF. Rapamycin normalizes HIF levels in TSC2−/− cells, indicating that TSC2 regulates HIF by inhibiting mTOR. In contrast, Rapamycin only partially downregulates VEGF in this setting, implying an mTOR-independent link between TSC2 loss and VEGF. This pathway may involve chromatin remodeling since the HDAC inhibitor Trichostatin A downregulates VEGF in TSC2−/− cells.
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