title: Dendritic effect of ligand-coated nanoparticles: enhanced apoptotic activity of silica-berberine nanoconjugates.
abstract: We describe the synthesis and biological characterization of a novel prototype, namely, silica nanoconjugates bearing a covalently linked berberine, a plant alkaloid known to have antiproliferative activity. The effect of synthesized nanoconjugates on cell proliferation, the cell cycle profile, and apoptosis in the human cervical carcinoma cell line (HeLa), human hepatocellular liver carcinoma cell line (HepG2), and human embryonic kidney (HEK) 293T cell line has been studied and compared with the results obtained for free berberine. Our results show that all the nanoconjugates display higher antiproliferative activity than free berberine. The ability of these nanoconjugates to inhibit cellular proliferation is mediated by the cell cycle arrest at the G1 phase. Moreover, silica nanoconugates caused selective apoptotic arrest with a higher efficiency than free berberine followed by apoptotic cell death as shown by quantitative fluorescence-activated cell sorting analyses. Efficiency of the nanoconjugates increases upon an increase in the linker chain length, demonstrating the distinct role of the spacer chain that conjugates nanoparticles and ligands. The actual reason to show enhanced efficiency by the nanoconjugates has not been elucidated in the present study; however, we hypothesize that an increase in local concentration due to the confinement of a ligand on the nanosurface ("dendritic" effect) might have led to the observed effect.
authors.affiliation: Proteomics and Structural Biology Unit, Institute of Genomics and Integrative Biology, Mall Road, New Delhi 110 007, India.
authors.forename: Mahantappa
authors.initials: M
authors.lastname: Halimani
authors.forename: S Prathap
authors.initials: SP
authors.lastname: Chandran
authors.forename: Sudhir
authors.initials: S
authors.lastname: Kashyap
authors.forename: V M
authors.initials: VM
authors.lastname: Jadhav
authors.forename: B L V
authors.initials: BL
authors.lastname: Prasad
authors.forename: Srinivas
authors.initials: S
authors.lastname: Hotha
authors.forename: Souvik
authors.initials: S
authors.lastname: Maiti
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001599:Berberine / Q000737:chemistry* / Q000494:pharmacology*; D002460:Cell Line; D006801:Humans; D008024:Ligands; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D012822:Silicon Dioxide / Q000737:chemistry*; D013053:Spectrophotometry
chemical_list: D008024:Ligands; D001599:Berberine; D012822:Silicon Dioxide