Improved Anti-Osteoporosis Potency and Reduced Endometrial Membrane Hyperplasia During Hormone Replacement Therapy with Estrogen−RGD Peptide Conjugates
摘要:
To improve the specificity and potency of estrogen replacement therapy therapeutics while also minimizing the side effects such as bone resorption and thickening of the uterine wall, a series of novel estrogen-derived conjugates estradiol-3-RGD, estradiol-17-RGD, and estrone-3-RGD peptides have been prepared. In a mouse model, intraperitoneal (i.p.) administration of these estrogen-RGD peptide conjugates resulted in decreased serum concentrations of calcium and alkaline phosphatase, as well as increased levels of calcium, phosphorus, and minerals in the mouse femur. Furthermore, the anti-osteoporosis action of these conjugates followed a dose-dependent manner and was accompanied with no observable effects on endometrial cell hyperplasia. In addition to all of these compounds exhibiting biological activity when administered by the i.p. route, we were particularly pleased to note that the estradiol-3-RGD and estradiol-17-RGD conjugates were both orally active.
To enhance the potency, reduce the side effects and improve oral property of estradiol in estrogen replacement therapy (ERT), 6 novel estradiol–RGD octapeptide conjugates have been prepared. In an ovariectomized mouse osteoporotic model, at an oral dosage of 110.3 nmol/kg per day, their anti-osteoporosis activity was significantly higher than that of estradiol and estradiol–RGD tetrapeptide conjugates
3D QSAR of novel estrogen–RGD peptide conjugates: Getting insight into structural dependence of anti-osteoporosis activity and side effect of estrogen in ERT
To explore the structural dependence of the oral potency and side effect of estrogen-RGD peptide conjugates, here six novel conjugates were prepared via introducing RGD-tetrapeptides into both 3- and 17-positions of estradiol, and introducing RGD-octapeptides into 3-position of estrone. In an ovariectomized mouse model they exhibited higher anti-osteoporosis activity and lower side effect than estrogen. For 3D QSAR analysis the anti-osteoporosis activities of nine known conjugates estrogen-RGD tetrapeptide conjugates were also provided. Using Cerius(2) module their 3D QSAR analysis was performed, four equations with high r(2) values were established, and the structural dependence of the oral potency and side effect of them was elucidated. (C) 2009 Elsevier Ltd. All rights reserved.