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10.18632/oncotarget.1837. [PMC free article] [PubMed] [CrossRef] [Google Scholar] 10. H520, and small cell lung malignancy, HTB171 in nude mice and human triple negative breast cancer, MDA-MB-231 and HCC1806 in SCID mice. H2aL2a significantly decreased tumor growth in both breast and both lung malignancy models. H2aL2a showed statistically equivalent or better efficacy than H3L3 and has superior production capabilities. These results suggest that H2aL2a may be superior as a naked antibody, as an antibody drug conjugate or as a radiolabeled antibody, however the higher affinity of H3L3 may lead to better efficacy in bi-specific Rabbit polyclonal to TLE4 therapies in which the binding is usually decreased due to the presence of only one TF-Ag- binding site. Keywords: hJAA-F11, TF-Ag, Thomsen-Friedenreich antigen, tumor immunotherapy, translational oncology INTRODUCTION The disaccharide D-galactose-beta-(1-3)-N-acetyl galactosamine-alpha (Gal–(1-3)-GalNAc-), known as Thomsen-Friedenreich antigen (TF-Ag-) or Core 1, is found on approximately 85% of human carcinomas but not on normal tissues. This makes TF-Ag- a encouraging target for malignancy therapeutics. Alterations in glycosylation in malignant cells lead to the elevated surface expression of TF-Ag- on malignancy cells, while TF-Ag- is usually naturally cryptic on normal tissues due to glycan chain extensions. [1C3] However, previous attempts at therapy utilizing this target have been limited due Metiamide to a lack of chemical and biological specificity of earlier antibodies developed to this target. Our patented humanized IgG1 antibody constructs H2aL2a and H3L3 (hJAA-F11 H2aL2a and hJAA-F11 H3L3) are the only humanized antibodies that are highly specific for true tumor associated TF-Ag alpha [4, 5]. Importantly, these antibodies do not bind to TF-Ag beta which is usually primarily linked to glycolipids on the surface of normal cells such as the central nervous system GM1 ganglioside, the asialo-GM1 of NK and kidney cells, the GD1 of glycolipids and the asialo- GM1 of peripheral nerve tissue. Thus, hJAA-F11 antibodies, the humanized versions of the murine monoclonal IgG3 antibody mJAA-F11 [4C12], hold promise towards targeting TF-Ag- expressing cancers for therapeutic and diagnostic Metiamide applications. During humanization of the mouse JAA-F11, 4 different constructs of the heavy chain and 4 different constructs of the light chain were made. The various combinations were tested and H2aL2a and H3L3 were selected as the most reactive to TF-Ag in an ELISA with TF-Ag–BSA as the target antigen [4]. Both H2aL2a and H3L3 showed antibody-dependent cellular cytotoxicity (ADCC) activity ADCC activity of H3L3 would seem to be predictive of improved therapeutic effect for this construct. However, previous work with other cancer therapeutic antibodies [13C15], has shown that beyond a Metiamide certain affinity threshold, increased affinity can result in less penetration in the tumor due to the binding-site barrier phenomenon, causing less efficacy. This decrease in efficacy seen with higher affinity has been suggested to be a deficiency that would globally impact all tumor types [13C15]. To test for the potential therapeutic efficacy and to determine how the difference in affinity affects the efficacy of H2aL2a and H3L3, four clinically relevant human malignancy mouse xenograft models were treated with each antibody construct. efficacy of the H2aL2a construct has been previously shown in the human triple negative breast malignancy (TNBC) MDA-MB-231 xenograft in Severe Combined Immunodeficient (SCID) mice [4]. In this statement, the efficacy of both H2aL2a and H3L3 are compared in lung and breast cancer human tumor xenograft models in immunocompromised mice. The tumor models utilized, both non-small cell squamous cell carcinoma and small cell lung malignancy and triple unfavorable breast malignancy are tumor types in which there is an unmet clinical need for targeted therapy. In immunohistochemical analysis of human tumors as shown in our previous work [5], these selected tumor types experienced high percentage of TF-Ag expression (specific reactivity with hJAA-F11 H2aL2a). 52 Individual cases of non-small cell squamous carcinomas were tested with hJAA-F11 H2aL2a and 96% were positive, 38 individual cases of small cell carcinomas were tested and 97% were positive. 126 individual cases of triple unfavorable breast tumors were tested and 94% were positive, Accordingly, the human non-small cell lung malignancy (NSCLC, (squamous cell), H520) and.