Beyond receptor expression levels: the relevance of target accessibility in ligand-directed pharmacodelivery systems.
For development of a new ligand-directed pharmacology, it is critical to measure delivery of targeted drug ligands via molecular imaging or diagnostic readouts (termed theranostics). Combinatorial peptide libraries serve as unbiased functional screens that can identify specific peptides targeting cell-surface receptors accessible to the circulation. As candidate drug leads, such peptides provide motifs likely to modify ligand-receptor interactions and downstream signal transduction pathways. This strategy is synergistic with genomic and proteomic approaches and has yielded insights into the specialized nature of the target tissue microenvironment. However, for this vision to be realized, one must look, as recent literature suggests, beyond receptor levels and critically analyze ligand accessibility as a key determinant in pharmacodelivery systems.
Ozawa
Michael G
MG
Department of Genitourinary Medical Oncology, The University of Texas M D Anderson Cancer Center, Houston, TX 77030, USA.
Zurita
Amado J
AJ
Dias-Neto
Emmanuel
E
Nunes
Diana N
DN
Sidman
Richard L
RL
Gelovani
Juri G
JG
Arap
Wadih
W
Pasqualini
Renata
R
D000626:Aminopeptidases / Q000378:metabolism; D020533:Angiogenesis Inhibitors / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D016503:Drug Delivery Systems; D015195:Drug Design; D006801:Humans; D008024:Ligands; D015336:Molecular Probe Techniques; D019151:Peptide Library; D011956:Receptors, Cell Surface / Q000378:metabolism*
D020533:Angiogenesis Inhibitors; D008024:Ligands; D019151:Peptide Library; D011956:Receptors, Cell Surface; D000626:Aminopeptidases