Date Published: February 22, 2018
Publisher: Public Library of Science
Author(s): Liselot M. Mus, Geertrui Denecker, Frank Speleman, Bart I. Roman, Valentin Ceña.
Effective inhibitors of invasion and metastasis represent a serious unmet clinical need. We have recently identified 4-fluoro-3’,4’,5’-trimethoxychalcone or C16 as a potent anti-invasive molecule. In this paper, we report on the development of an optimized vehicle for oral administration of C16. We also explore its pharmacokinetic and toxicity profile in rodents as a prelude to a broad-scope evaluation as a pharmacological tool in animal models of disease. C16 showed suboptimal pharmacokinetics with limited oral bioavailability and whole blood stability. Rapid metabolism with elimination via glutathione conjugation was observed. An oral dosing routine using medicated gels was developed to overcome bioavailability issues and yielded sustained whole blood levels above the half maximal effective concentration (EC50) in a 7-day study. The compound proved well-tolerated in acute and chronic experiments at 300 mg/kg PO dosing. The medicated gel formulation is highly suitable for evaluation of C16 in animal models of disease.
In the malignant progression of a solid tumor the gain of an invasive phenotype is the first and a necessary step in the development of metastases [1,2]. The sequelae of metastasis account for 90% of cancer-related mortality. To date, the biological events underlying invasion and metastasis remain poorly understood . The development of effective anti-invasive/antimetastatic tools and drugs is therefore an unmet clinical need .
Additional protocols are available in S1 File.
4-Fluoro-3’,4’,5’-trimethoxychalcone or C16 is a small molecule with nanomolar anti-invasive activity, a defined structure-activity relationship and a satisfactory ADME and toxicity profile in vitro [5–9]. In order to examine its potential as a pharmacological tool, prior exploration of its in vivo pharmacokinetic profile, toxicity and tolerability was required. The obtained data is also relevant to several other members of the chalcone chemical class, which have been attributed biological activities (mostly at elevated concentrations) , but for which associated DMPK profiling is lacking.
C16, like other members of the chalcone family [13,14], shows suboptimal pharmacokinetics in the rat and the mouse. Its limited solubility and cellular metabolism causes poor intestinal uptake and limited oral bioavailability. The compound is rapidly metabolized, with a clearance rate exceeding hepatic blood flow. Glutathione conjugation in erythrocytes was identified as a major route of extra-hepatic elimination, explaining the much shorter half-life of C16 in blood versus plasma. An oral dosing routine using medicated gels was developed that solved these issues. A schedule providing amounts equivalent to oral gavage at 100 mg/kg three times per day yielded sustained whole blood levels above the EC50 in a 7-day chronic study. The compound showed good tolerability during the latter experiment. Evaluation of C16 as a pharmacological tool in animal models of metastatic disease, using the medicated gel formulation, is currently ongoing. Besides, we are preparing analogs with a superior DMPK profile in search of improved clinical relevance.