Thymidine Phosphorylase Gene Transfer Inhibits Vascular Smooth Muscle Cell Proliferation by Upregulating Heme Oxygenase-1 and p27 ^KIP1

Abstract

Objective-Thymidine phosphorylase (TP) reportedly promotes endothelial cell migration and induces heme oxygenase (HO)-1 expression. However, its effect on vascular smooth muscle cells (VSMCs) is poorly understood. In this study, we examined the effect of TP on VSMCs in vitro and in vivo. Methods and Results-Phagemid vector encoding human TP gene was transfected into rat VSMCs, and a clone overexpressing TP was selected (C2). C2 showed a slower migration and proliferation than VSMCs cloned with empty vector (pC) under basal, serum-stimulated, and hypoxic conditions. This decrease in proliferation correlated with TP-induced HO-1 expression and was reversed by inhibitors of either TP or HO activity. Furthermore, in C2, the cyclin-dependent kinase inhibitor (p27 KIP1 ) was much more abundant than in pC, and the cell cycle was arrested at the G1 phase. TP or HO activity inhibitors decreased p27 KIP1 expression in C2 to the level seen in pC. Adventitial TP gene delivery significantly reduced neointimal VSMC migration and neointima formation in balloon-injured rat carotid arteries. Conclusions-TP

Thymidine Phosphorylase Participates in Platelet Signaling and Promotes Thrombosis

“…We also found that TYMP inhibited vascular smooth muscle cell (VSMC) proliferation and migration 11–13 . The inhibitory role of TYMP on VSMC is partly mediated by regulating the phosphorylation of Lyn 12 , an important non-receptor tyrosine kinase of the Src family.…”

Regulation and Novel Action of Thymidine Phosphorylase in Non-Small Cell Lung Cancer: Crosstalk with Nrf2 and HO-1

“…Thus far, coexpression of TP and HO-1 has already been reported in clinical specimens of human malignant vertical growth melanomas in macrophages [29]. Studies in vitro implicated that HO-1 could only play a role downstream of TP, as was described in vascular smooth muscle cells or bladder carcinoma, where TP overexpression resulted in induction of HO-1 expression [5], [30]. We provide here mechanistic data showing that the regulation is indirect, potentially involving modulation of oxidative status of the cell, as the effects of Nrf2 or HO-1 on TP expression were mimicked by treatment of control cells with an antioxidant N-acetylcysteine.…”

Adventitial delivery of platelet-derived endothelial cell growth factor gene prevented intimal hyperplasia of vein graft

“…15,[27][28][29] We used gene transfection of human PD-ECGF/TP into rat VSMCs to study the mechanism of inhibitory effect of PD-ECGF/TP on VSMC, and found that inhibition of VSMC proliferation was correlated with the upregulation of p27 KIP1 and HO-1. 15 We also found that adventitial gene transfer of TP/PD-ECGF in a balloon injury rat carotid artery model markedly inhibited the intimal hyperplasia. Interestingly, another group also reported that the addition of the PD-ECGF/TP protein into the cultured media inhibited DNA synthesis of cultured VSMCs in vitro, 30 suggesting the repeatable inhibitory effect of PD-ECGF/TP on VSMC proliferation.…”

“…The potential mechanisms may include, at least in part, upregulation of heme oxygenase-1 (HO-1) expression and consequently increased p27 KIP1 in cultured VSMCs. 15 These observations strongly suggest that PD-ECGF/TP gene therapy might have an effect on preventing vein graft failure by reducing intimal thickness. In the present study, we demonstrated for the first time to our knowledge that adventitial gene administration of PD-ECGF/TP significantly decreased the proliferative VSMC in the hyperplastic intima and markedly inhibited neointimal thickening of vein graft.…”