RESUMEN
Myo-inositol hexakisphosphate (IP6) is a natural product known to inhibit vascular calcification (VC), but with limited potency and low plasma exposure following bolus administration. Here we report the design of a series of inositol phosphate analogs as crystallization inhibitors, among which 4,6-di-O-(methoxy-diethyleneglycol)-myo-inositol-1,2,3,5-tetrakis(phosphate), (OEG2)2-IP4, displays increased in vitro activity, as well as more favorable pharmacokinetic and safety profiles than IP6 after subcutaneous injection. (OEG2)2-IP4 potently stabilizes calciprotein particle (CPP) growth, consistently demonstrates low micromolar activity in different in vitro models of VC (i.e., human serum, primary cell cultures, and tissue explants), and largely abolishes the development of VC in rodent models, while not causing toxicity related to serum calcium chelation. The data suggest a mechanism of action independent of the etiology of VC, whereby (OEG2)2-IP4 disrupts the nucleation and growth of pathological calcification.
Asunto(s)
Fosfatos de Inositol/química , Fosfatos de Inositol/farmacología , Calcificación Vascular/tratamiento farmacológico , 6-Fitasa/metabolismo , Adenina/efectos adversos , Animales , Células Cultivadas , Evaluación Preclínica de Medicamentos/métodos , Dispersión Dinámica de Luz , Glicol de Etileno/química , Humanos , Inyecciones Subcutáneas , Fosfatos de Inositol/farmacocinética , Masculino , Músculo Liso Vascular/citología , Músculo Liso Vascular/efectos de los fármacos , Ratas Sprague-Dawley , Uremia/tratamiento farmacológico , Uremia/fisiopatología , Calcificación Vascular/inducido químicamente , Difracción de Rayos XRESUMEN
PURPOSE: TMX-101 and TMX-202 are formulations of toll-like receptor 7 (TLR-7) agonists, under investigation for the treatment of urothelial carcinoma. Our goal was to evaluate the efficacy of intravesical instillations of TMX-101 or TMX-202 in an orthotopic bladder cancer rat model. METHODS: Four groups of 14 rats received an instillation with isogenic AY-27 tumor cells on day 0, starting tumor development. On day 2 and 5, the rats were treated with an intravesical instillation of TMX-101 0.1%, TMX-202 0.38%, vehicle solution or NaCl. On day 12 the rats were sacrificed and the bladders were evaluated histopathologically. RESULTS: No signs of toxicity were seen. The number of tumor-positive rats was 11 of 14 (79%) in the vehicle control group and in the NaCl control group, versus 9 of 14 (64%) in the TMX-101-treated group, and 8 of 14 (57%) in the TMX-20-treated group. The difference between tumor-bearing rats in the treated and control groups was not significant (p = 0.12). Bladder weight was significantly lower for TMX-202-treated rats compared to vehicle (p = 0.005). CONCLUSIONS: TMX-101 and TMX-202 are TLR-7 agonists with antitumor activity. Treatment with TMX-101 and TMX-202 resulted in less tumor-bearing rats compared to vehicle or saline control groups, although not statistically significant. In this aggressive bladder cancer model, a lower number of tumor-positive rats after treatment with TLR-7 agonists indicates activity for the treatment of non-muscle invasive bladder cancer.