title: Silk fibroin mediated delivery of liposomal emodin to breast cancer cells.
abstract: The efficacy of a drug is dependent on its mode of delivery and its potency at the tumor site. In this study, the drug delivery and efficacy of silk fibroin coated liposomes (SF-ELP), encapsulating a receptor tyrosine kinase inhibitor, emodin, on Her2/neu over-expressing breast cancer cells, was investigated. This study demonstrates that SF-ELP was more efficacious in suppressing the growth of Her2/neu over-expressing breast cancer cells MDA-MB-453 and BT-474 as compared to uncoated emodin loaded liposomes (ELP). Reduced levels of phosphorylated Her2/neu correlated with growth inhibition observed in the MDA-MB-453 cells, treated with both ELP and SF-ELP. ELP treatment of MDA-MB-453 breast cancer cells resulted in inhibition of the PI3K pathway whereas SF-ELP treatment inhibited both the PI3K and MAPK pathways, which contributed to the enhanced growth inhibitory effects of Her2/neu over-expressing breast cancer cells. Coating of ELP with silk fibroin did not alter the target specificity of emodin, on the other hand the emodin efficacy was enhanced. Higher uptake of emodin delivered by SF-ELP lead to increased cell death as compared to emodin delivery via ELP. Silk fibroin coating around the liposome imparts an extra layer that emodin has to extravasate in order to release from the encapsulating liposome. This increases retention of the drug in the cell for a longer time and protects emodin from quick release and metabolism. Longer intracellular retention may lead to the longer availability of emodin for down-modulation of various Her2/neu pathways. This study demonstrates that silk fibroin coating enhanced emodin delivery in Her2/neu over-expressing breast cancer cells thereby increasing the overall efficacy of the drug.
authors.affiliation: University of Texas M.D. Anderson Cancer Center, Departments of Biomedical Engineering and Plastic Surgery, Unit 602, P.O. Box 301402, Houston, TX 72230-1402, United States.
authors.forename: Sangeeta K
authors.initials: SK
authors.lastname: Cheema
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Gobin
authors.forename: Robyn
authors.initials: R
authors.lastname: Rhea
authors.forename: Gabriel
authors.initials: G
authors.lastname: Lopez-Berestein
authors.forename: Robert A
authors.initials: RA
authors.lastname: Newman
authors.forename: Anshu B
authors.initials: AB
authors.lastname: Mathur
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D001692:Biological Transport; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002626:Chemistry, Pharmaceutical; D004305:Dose-Response Relationship, Drug; D004337:Drug Carriers; D004339:Drug Compounding; D004642:Emodin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D005349:Fibroins / Q000737:chemistry*; D005434:Flow Cytometry; D006801:Humans; D008081:Liposomes; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology* / Q000627:therapeutic use; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors
chemical_list: D000970:Antineoplastic Agents; D004337:Drug Carriers; D004642:Emodin; D005349:Fibroins; D008081:Liposomes; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D018719:Erb-b2 Receptor Tyrosine Kinases; C482288:fibroin, silkworm; C508053:ERBB2 protein, human