Construction of Synthetic VHH Libraries in Ribosome Display Format.

Single-domain antibodies, or VHH, represent an attractive molecular basis to design affinity proteins with favorable properties. Beyond high affinity and specificity for their cognate target, they usually show high stability and high production yields in bacteria, yeast, or mammalian cells. In addition to these favorable properties, their ease of engineering makes them useful for many applications. Until the past few years, the generation of VHH involved the immunization of a Camelidae with the target antigen, followed by a phage display selection using phage libraries encoding the VHH repertoire of the animal blood sample. However, this approach is constrained by the accessibility to the animals, and the output relies on the animal's immune system.Recently, synthetic VHH libraries have been designed to avoid the use of animals. Here, we describe the construction of VHH combinatorial libraries and their use for the selection of binders by ribosome display, a fully in vitro selection technique.

Structural investigation on thiazolo[5,4-d]pyrimidines to obtain dual-acting blockers of CD73 and adenosine A2A receptor as potential antitumor agents.

Adenosine pathway, including its generating enzyme (CD73) and its receptors represents a key target for cancer immunotherapy. Here we aimed to search for novel compounds able to co-target the CD73 and the A2A adenosine receptor (A2A AR) as dual-blockers of adenosine generation and activity. The design project was to combine in the same molecule the thiazolo[5,4-d]pyrimidine core, an essential pharmacophoric feature to block the A2A AR, with a benzenesulfonamide group which is a characteristic group of CD73 inhibitors. Most of the reported compounds resulted in inverse agonists of the human (h) A2A AR endowed with high affinity, selectivity and potency. However they were weak inhibitors of CD73 enzyme. Nevertheless, this study can be considered as a starting point to develop more active compounds.