Dendrimer-based anticancer nanotherapeutics containing ∼5 folate molecules have shown in vitro and in vivo efficacy in cancer cell targeting. Multivalent interactions have been inferred from observed targeting efficacy, but have not been experimentally proven. This study provides quantitative and systematic evidence for multivalent interactions between these nanodevices and folate-binding protein (FBP). A series of the nanodevices were synthesized by conjugation with different amounts of folate. Dissociation constants (KD) between the nanodevices and FBP measured by SPR are dramatically enhanced through multivalency (∼2,500- to 170,000-fold). Qualitative evidence is also provided for a multivalent targeting effect to KB cells using flow cytometry. These data support the hypothesis that multivalent enhancement of KD, not an enhanced rate of endocytosis, is the key factor resulting in the improved biological targeting by these drug delivery platforms.
Bibliographical noteFunding Information:
This work has been funded with federal funds from the National Cancer Institute, National Institutes of Health, under contract # N01-CO-27173. This research has been also supported by State of Michigan MEDC funding under GR-472, grant # 085P3000548. The University of Michigan has licensed this technology to a start-up company, Avidimer Therapeutics, and Dr. Baker has a significant equity position in this entity. The authors thank Ankur Desai for his assistance with GPC measurements.
All Science Journal Classification (ASJC) codes
- Molecular Medicine
- Molecular Biology
- Drug Discovery
- Clinical Biochemistry