Protein labeling approach to improve lysosomal targeting and efficacy of antibody-drug conjugates.

An anti-EGFR nanobody was labeled at the C-terminus with a lysosome-sorting NPGY (Asn-Pro-Gly-Tyr) motif via sortase-mediated ligation to enhance the engagement of the clathrin-mediated endocytosis. The synergistic effects of NPGY motif and nona-arginine peptide were found to induce robust internalization and lysosomal trafficking, which in turn improved anti-tumor activity of an antibody-drug conjugate.

Highly efficient regio-selective ring-opening nucleophilic fluorination of aziridines and azetidines: access to ß- or γ-fluorinated amino acid derivatives.

Herein, we have presented a facile and efficient method of ring-opening nucleophilic fluorination of aziridines, affording highly regio-selective ß-fluorinated amines. Firstly, the example of ring-opening hydrofluorination of azetidines was reported. Then, the Olah's reagent also provided a promising method for the construction of enantioenriched ß-fluoro-α-amino acid derivatives, which could be used for the preparation of peptide-based bioactive molecules.

Site-specific labeling of an anti-MUC1 antibody: probing the effects of conjugation and linker chemistry on the internalization process.

Antibody-drug conjugates (ADCs) have recently received enormous attention as an attractive approach for cancer therapy. Although ADC design has been believed to be important for the relative efficacy of ADCs, it remains unexplored how the structural characteristics of ADCs would impact the internalization process and intracellular trafficking of the molecules. Herein, we report our efforts in investigating the cellular endocytosis implications of the conjugation and linker chemistry in designing antibody-based agents. A series of anti-MUC1 single-chain variable fragment (scFv-SM3) conjugates were designed with unique structural characteristics ranging from conjugation methods, sites of attachment and linker chemistry. In vitro confocal imaging showed that both random lysine-conjugation and site-specific conjugation, including C-terminus modification or internal site conjugation, could afford antibody conjugates with similar binding affinity and cellular uptake to target-expressing cells. Time-course internalization studies demonstrated that SM3-conjugates with short polyethylene glycol linkers outcompeted those that lack any hydrophilic linkers for higher cellular uptake and faster internalization rate. The SM3-conjugates with the highest affinity and internalization rate were also tested in mouse xenograft models using MUC1-overexpressing tumor cells. Our results indicate that the linker and conjugation chemistry play an important role in the internalization process of antibody conjugates, and this in turn could impact the therapeutic effects of ADCs.

Catalytic Asymmetric [4 + 3] Annulation of C, N-Cyclic Azomethine Imines with Copper Allenylidenes.

The first asymmetric decarboxylative [4 + 3] annulation of propargylic carbamates with C, N-cyclic azomethine imines has been developed successfully by a copper- N-heterocyclic carbine system. This strategy led to a series of optically active isoquinoline-fused triazepine derivatives in good yields and with excellent enantio- and diastereoselectivities. Remarkably, Cu-allenylidene intermediates play a crucial role in this transformation.