Real-time analysis of uptake and bioactivatable cleavage of luciferin-transporter conjugates in transgenic reporter mice

Departments of *Chemistry,
^‡Chemical and Systems Biology, Pediatrics, Radiology, and Microbiology and Immunology, Stanford University, Stanford, CA 94305-5080

Contributed by Paul A. Wender, May 4, 2007

Abstract

Many therapeutic leads fail to advance clinically because of bioavailability, selectivity, and formulation problems. Molecular transporters can be used to address these problems. Molecular transporter conjugates of otherwise poorly soluble or poorly bioavailable drugs or probes exhibit excellent solubility in water and biological fluids and at the same time an enhanced ability to enter tissues and cells and with modification to do so selectively. For many conjugates, however, it is necessary to release the drug/probe cargo from the transporter after uptake to achieve activity. Here, we describe an imaging method that provides quantification of transporter conjugate uptake and cargo release in real-time in animal models. This method uses transgenic (luciferase) reporter mice and whole-body imaging, allowing noninvasive quantification of transporter conjugate uptake and probe (luciferin) release in real time. This process effectively emulates drug-conjugate delivery, drug release, and drug turnover by an intracellular target, providing a facile method to evaluate comparative uptake of new transporters and efficacy and selectivity of linker release as required for fundamental studies and therapeutic applications.

Footnotes

^†To whom correspondence should be addressed. E-mail: wenderp{at}stanford.edu
Author contributions: P.A.W., E.A.G., L.R.J., T.H.P., J.B.R., R.S., and C.H.C. designed research; E.A.G., L.R.J., T.H.P., J.B.R., and R.S. performed research; E.A.G. contributed new reagents/analytic tools; P.A.W., E.A.G., L.R.J., T.H.P., J.B.R., R.S., and C.H.C. analyzed data; P.A.W., E.A.G., L.R.J., T.H.P., J.B.R., R.S., and C.H.C. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
↵ § For recent reviews on transporters, including lead references to work on guanidinium transporters from the groups of Torchilin, Prochiantz, Langel, Futaki, Vives, Wender, Doudy, Piwnica-Worms, Seebach, Gellman, Goodman, and others, see: (2005) Adv. Drug Deliv. Rev. 57:489–651.
This article contains supporting information online at www.pnas.org/cgi/content/full/0703919104/DC1.