Oral targeted delivery by nanoparticles enhances efficacy of an Hsp90 inhibitor by reducing systemic exposure in murine models of colitis and colitis-associated cancer

Background and Aims: Heat shock protein 90 [Hsp90]-targeted therapy has been proposed as a promising strategy for the treatment of ulcerative colitis [UC] and colitis-associated cancer [CAC]. Systemic administration of the Hsp90 inhibitor, 17-AAG, was found to be profoundly protective in preclinical mouse models of inflammatory bowel disease [IBD]. However, the therapeutic potential of 17-AAG is limited by potential side effects associated with its systemic exposure and the modest bioavailability afforded by its oral administration. Methods: To address these issues, we used a versatile single-step surface-functionalizing technique to prepare a 17-AAG oral delivery system using PLGA/PLA-PEG-FA nanoparticles [NP-PEG-FA/17-AAG]. Results: NP-PEG-FA could be efficiently taken up by mouse Colon-26 cells and activated Raw 264.7 cells in vitro and by inflamed mouse colitis tissues in vivo. The therapeutic efficacy of orally administrated NP-PEG-FA/17-AAG was evaluated in in vivo models using dextran sulphate sodium [DSS]-induced UC and azoxymethane [AOM]/DSS-induced CAC, and the results indicated that NP-PEG-FA/17-AAG significantly alleviated the symptoms of UC and CAC. More importantly, our inflamed colitis-targeted 17-AAG nano-formulation reduced systemic exposure and provided a degree of therapeutic response similar to that obtained by systemic administration [intraperitoneal] of 17-AAG, but at a ten-fold lower dose. Conclusions: We describe a convenient, orally administrated 17-AAG delivery system that exhibits enhanced efficacy in UC and CAC therapy while reducing systemic exposure. This system may represent a promising therapeutic approach for treating UC and CAC.