title: Human Serum Albumin and HER2-Binding Affibody Fusion Proteins for Targeted Delivery of Fatty Acid-Modified Molecules and Therapy.
abstract: Human epidermal growth factor receptor 2 (HER2) is a well-studied therapeutic target as well as a biomarker of breast cancer. HER2-targeting affibody (ZHER2:342) is a novel small scaffold protein with an extreme high affinity against HER2 screened by phage display. However, the small molecular weight of ZHER2:342has limited its pharmaceutical application. Human serum albumin (HSA) and ZHER2:342fusion protein may not only extend the serum half-life of ZHER2:342but also preserve the biological function of HSA to bind and transport fatty acids, which can be used to deliver fatty acid-modified therapeutics to HER2-positive cancer cells. Two HSA and ZHER2:342fusion proteins, one with a single ZHER2:342domain fused to the C terminus of HSA (rHSA-ZHER2) and another with two tandem copies of ZHER2:342fused to the C terminus of HSA (rHSA-(ZHER2)2), have been constructed, expressed, and purified. Both fusion proteins possessed the HER2 and fatty acid (FA) binding abilities demonstrated by in vitro assays. Interestingly, rHSA-(ZHER2)2, not rHSA-ZHER2, was able to inhibit the proliferation of SK-BR-3 cells at a relatively low concentration, and the increase of HER2 and ERK1/2 phosphorylation followed by rHSA-(ZHER2)2treatment has been observed. HSA fusion proteins are easy and economical to express, purify, and formulate. As expected, HSA fusion proteins and fusion protein-bound fatty acid-modified FITC could be efficiently taken up by cells. These results proved the feasibility of using HSA fusion proteins as therapeutic agents as well as carriers for targeted drug delivery.
authors.forename: Daoyuan
authors.initials: D
authors.lastname: Dong
authors.affiliation: Department of Pathology, Drexel University College of Medicine , Philadelphia, Pennsylvania 19102, United States.
authors.forename: Guanjun
authors.initials: G
authors.lastname: Xia
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Li
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Li
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D005227:Fatty Acids / Q000737:chemistry; D006801:Humans; D047468:Immunoprecipitation; D061986:MCF-7 Cells; D010766:Phosphorylation; D011485:Protein Binding; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000737:chemistry / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism*; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D012709:Serum Albumin; C508053:ERBB2 protein, human
keywords: HER2; affibody; albumin; fusion protein; targeted drug delivery