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BackgroundAntibody-based therapeutics is a rapidly growing field. Small engineered antibody fragments demonstrate similar antigen affinity compared with the parental antibody but have a shorter serum half-life and possess the ability to be conjugated to nanoparticles. The goal of this study was to engineer an anti-carbohydrate antigen 19-9 (CA19-9) cys-diabody fragment in hopes of targeting nanoparticles to pancreatic cancer.MethodsThe anti-CA19-9 cys-diabody was created by engineering a C-terminal cysteine residue into the DNA single-chain Fv construct of the anti-CA19-9 diabody and expressed in NS0 cells. Maleimide chemistry was used to conjugate the cys-diabody to polymerized liposomal nanoparticles (PLNs) through the cysteine residues. Flow cytometry was used to evaluate targeting of cys-diabody and cys-diabody-PLN conjugate to human pancreatic cancer cell lines. The cys-diabody was radiolabeled with a positron emitter ((124)I) and evaluated in a mouse model of CA19-9-positive and CA19-9-negative xenografts with micro-positron emission tomography/micro-computed tomography at successive time intervals after injection. Percentage of injected dose per gram of radioactivity was measured in blood and tumor to provide objective confirmation of the micro-positron emission tomographic images.ResultsTumor xenograft imaging of the anti-CA19-9 cys-diabody demonstrated an average tumor-to-blood ratio of 3.0 and positive-to-negative tumor ratio of 7.4. Successful conjugation of the cys-diabody to PLNs was indicated by flow cytometry showing specific binding of cys-diabody-PLN conjugate to human pancreatic cancer cells in vitro.ConclusionsOur results show that the anti-CA19-9 cys-diabody targets pancreatic cancer providing specific molecular imaging in tumor xenograft models. Furthermore, the cys-diabody-PLN conjugate demonstrates target-specific binding of human pancreatic cancer cells with the potential to deliver targeted treatment.

Osteosarcoma is the most common primary malignancy of bone in children, adolescents, and adults. Despite extensive surgery and adjuvant aggressive high-dose systemic chemotherapy with potentially severe bystander side effects, cure is attainable in about 70% of patients with localized disease and only 20%-30% of those patients with metastatic disease. Targeted therapies clearly are warranted in improving our treatment of this adolescent killer. However, a lack of osteosarcoma-associated/specific markers has hindered development of targeted therapeutics. We describe a novel osteosarcoma-associated cell surface antigen, ALCAM. We, then, create an engineered anti-ALCAM-hybrid polymerized liposomal nanoparticle immunoconjugate (α-AL-HPLN) to specifically target osteosarcoma cells and deliver a cytotoxic chemotherapeutic agent, doxorubicin. We have demonstrated that α-AL-HPLNs have significantly enhanced cytotoxicity over untargeted HPLNs and over a conventional liposomal doxorubicin formulation. In this way, α-AL-HPLNs are a promising new strategy to specifically deliver cytotoxic agents in osteosarcoma.

Research reveals that the addition of anionic groups to liposomes containing polyvalent monomeric sialyl Lewis (sup)x-like oligosaccharide groups enhance inhibitory effect on selectin binding. Data further show that additional anionic sulfate esters in the liposomes result in highly inhibitory membranes.

A nonreductive technique to derive oligosaccharides with allylamide groups efficiently at the glycosidic position involves three steps. The first step melts unprotected oligosaccharide in allylamine. This step is followed by the two-step reaction which starts with the attack of allylamine on the anomeric hydroxyl group of the oligosaccharide. The final steps involves 3'-acetic acid-Gal-beta-1,4-(Fuc alpha-1,3)Glc.

The sialyl Lewis X determinant NeuAc-alpha-2,3-Gal-beta-1,4-(Fuc-alpha-1,3)-GlcNAc was prepared from a trisaccharide treated with GDP-fucose utilizing the fucosyltransferase. On the other hand, beta-O-allyl Le(super x) was prepared from the treatment of beta-O-(2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl)trichloroacetimidate with the beta-O-allyl glycoside of a selectively protected GlcNAc derivative toyield beta-O-allyyl-N-acetyllactosamine. The fucose was inserted into the intermediate product via an enzymatic glycosylation reaction to finally give the target compound.

Probe sonication method helps prepare polymerizable liposomes capable of binding to influenza virus particles. These liposomes are biomolecular materials having a molecular recognition function, sialic acid, and a detection element, polydiacetylene backbone. Binding of these liposomes leads to a visible color change, and absorption spectroscopy helps quantify the color change. Competitive inhibition studies help confirm the specificity of the color change.

An investigation on polymerized liposomes containing alpha-C-glycosides of sialic acid is presented. A polymerizable sialoside lipid is synthesized to form liposome mixtures that are found to be inhibitors of influenza virus in vitro infectivity. Further studies have shown that the capacity of a sialoside to inhibit hemagglutination does not necessarily reflect its capacity to inhibit infectivity.