Synthesis of the next-generation therapeutic antibodies that combine cell targeting and antibody-catalyzed prodrug activation

Abstract

An obstacle in the utilization of catalytic Abs for selective prodrug activation in cancer therapy has been systemic tumor targeting. Here we report the generation of catalytic Abs that effectively target tumor cells with undiminished prodrug activation capability. Ab conjugates were prepared by covalent conjugation of an integrin ␣v␤3-targeting antagonist to catalytic Ab 38C2 through either sulfide groups of cysteine residues generated by reduction of the disulfide bridges in the hinge region or surface lysine residues not involved in the catalytic activity. Using flow cytometry, the Ab conjugates were shown to bind efficiently to integrin ␣v␤3-expressing human breast cancer cells. The Ab conjugates also retained the retro-aldol activity of their parental catalytic Ab 38C2, as measured by methodol and doxorubicin (dox) prodrug activation. Complementing these Ab conjugates, an evolved set of dox prodrugs was designed and synthesized. Dox prodrugs that showed higher stability and lower toxicity were evaluated both in the presence and absence of the integrin ␣v␤3-targeting 38C2 conjugates for cell-killing efficacy by using human breast cancer cells. Our study reveals that cell targeting and prodrug activation capabilities can be efficiently combined for selective chemotherapy with novel dox prodrugs.aldolase Ab ͉ Ab conjugate ͉ doxorubicin ͉ integrin ␣v␤3

Versatile approach to α-alkoxy carbamate synthesis and stimulus-responsive alcohol release

“…1). This design has been implemented in elegant studies from the Shabat, 3 Shin, 4 and Sinha 5 groups. These successful constructs highlight the utility of the design yet reveal that enhanced synthetic accessibility would be desirable for rapid property optimization.…”

Characterization of a fusion protein of RGD4C and the ß-lactamase variant for antibody-directed enzyme prodrug therapy

“…Immune responses could not be prevented by cyclosporine administration and therefore limited the number of treatment cycles per patient. It is not known whether carboxypeptidase G2 contains T-cell epitopes 11. However, several other factors could have contributed to the immunogenicity observed in these ADEPT trials 12…”

Targeting Cell Surface Alpha(v)beta(3) Integrin Increases Therapeutic Efficacies of a Legumain Protease-Activated Auristatin Prodrug

“…1 Fortunately, such potent cytotoxins can be formulated as prodrugs, and delivered to tumor or in tumor microenvironments (TMEs) using various tumor-targeting agents, including monoclonal antibodies (Abs) or a small molecule inhibitors. 2 Previously, we have synthesized and examined a series of doxorubicin, 3,4 enediyne 5 and duocarmycin analog. 6 Prodrugs that are activated using the monoclonal aldolase Ab 38C2 7 or 93F3.…”