RESUMO
The human Na+/K+-ATPase (NKA) is a plasma membrane ion pump that uses ATP to help maintain the resting potential of all human cells. Inhibition of the NKA leads to cell swelling and death. The results of this investigation show that on cancer cells, the NKA either comes in close proximity to, associate with or complexes to important cancer-related proteins, and thus can be targeted with a new type of precision therapy called the extracellular drug conjugate or EDC. The EDCs reported here exhibit EC50 values in the low to mid-picomolar range, and signal to noise ratios > 1,000:1, both of which are dependent on the cell surface expression of the NKA and corresponding cancer-related target. We demonstrate that a potent small molecule inhibitor of the NKA can be covalently attached to antibodies targeting CD20, CD38, CD56, CD147, or dysadherin, to create a series of selective and powerful EDCs that kill cancer cells extracellularly by a mechanism resembling necrosis. This is therefore a framework for the development of a new type of precision therapy wherein exquisite selectivity is achieved for targeting extracellular disease-related proteins.
Assuntos
Anticorpos/química , Antineoplásicos/administração & dosagem , Imunoconjugados/administração & dosagem , Proteínas de Neoplasias/metabolismo , Neoplasias/tratamento farmacológico , Bibliotecas de Moléculas Pequenas/química , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Imunoconjugados/química , Imunoconjugados/farmacologia , Camundongos , Estrutura Molecular , Terapia de Alvo Molecular , Proteínas de Neoplasias/imunologia , Neoplasias/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The potential of a uniquely permissive engineered glycosyltransferase (OleD ASP) as a catalyst for steroid glycosylation is highlighted. The ability of OleD ASP to glucosylate a range of cardenolides and bufadienolides was assessed using a rapid LC-UV/MS-SPE-NMR analytical platform. While a bias toward OleD-catalyzed C3 monoglucosylation was observed, subtle alterations of the steroidal architecture, in some cases, invoked diglucosylation or, in one case (digoxigenin), C12 glucosylation. This latter case represents the first, and highly efficient, synthesis of digoxigenin 12-O-ß-D-glucoside.
Assuntos
Digoxigenina/análogos & derivados , Digoxigenina/química , Glucosídeos/síntese química , Glicosiltransferases/metabolismo , Esteroides/química , Catálise , Digoxigenina/síntese química , Digoxigenina/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Glucosídeos/química , Glicosilação , Glicosiltransferases/química , Humanos , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Ressonância Magnética Nuclear Biomolecular , EstereoisomerismoRESUMO
It is known that 3-O-glycosylation of glucosidic acceptors bearing acyl groups in the 4 and 6 positions instead of a 4,6-O-benzylidene ring mainly affords alpha-glycosides. Described here is an unexpected stereochemical outcome for elongation at glucose O-3 of a beta-d-Glcp-(1-->3)-alpha-d-Manp disaccharide using peracetylated ethyl thioglucoside as a donor. This unexpected reaction was correlated with match-mismatch effects, as shown by efficient coupling of the same acceptor by a donor of l-configuration.