Camelid reporter gene imaging: a generic method for in vivo cell tracking

A high affinity nanobody against endothelin receptor type B: a new approach to the treatment of melanoma

The aim of the study was to produce a single-domain antibody (nanobody) specific for endothelin receptor type B (EDNRB) which has high expression in melanoma. Cultured human melanoma cells were used as antigens to immunize alpacas. After antibody generation was verified in alpaca serum, total RNA was extracted from alpaca lymphocytes and the target V_HH fragment was amplified by two-step PCR, cloned in the pCANTAB5E phagemid vector, and used to transform Escherichia coli TG1 cells to obtain a phage-display nanobody library, which was enriched by panning. The results indicated successful construction of a phage-display anti-human melanoma A375 nanobodies library with a size of 1.2 × 10⁸/ml and insertion rate of 80%. After screening, eight positive clones of anti-EDNRB nanobodies were used to infect E. coli HB2151 for production of soluble nanobodies, which were identified by ELISA. Finally, we obtained a high-affinity anti-EDNRB nanobody, which consisted of 119 amino acids (molecular weight: 12.97 kDa) with 22 amino acids in CDR3 and had good affinity in vitro. The results suggest that the nanobody may be potentially used for the treatment of human melanoma.

Tracking stem cells with superparamagnetic iron oxide nanoparticles: perspectives and considerations

Superparamagnetic iron oxide nanoparticles (SPIONs) have been used for diagnoses in biomedical applications, due to their unique properties and their apparent safety for humans. In general, SPIONs do not seem to produce cell damage, although their long-term in vivo effects continue to be investigated. The possibility of efficiently labeling cells with these magnetic nanoparticles has stimulated their use to noninvasively track cells by magnetic resonance imaging after transplantation. SPIONs are attracting increasing attention and are one of the preferred methods for cell labeling and tracking in preclinical and clinical studies. For clinical protocol approval of magnetic-labeled cell tracking, it is essential to expand our knowledge of the time course of SPIONs after cell incorporation and transplantation. This review focuses on the recent advances in tracking SPION-labeled stem cells, analyzing the possibilities and limitations of their use, not only focusing on myocardial infarction but also discussing other models.

Oligo-clonal nanobodies as an innovative targeting agent for cancer therapy: New biology and novel targeting systems

Variable heavy chain of HcAb (VHH), the smallest intact antibody fragment, possesses sub-nanomolar affinity to antigens. In spite of conventional antibodies, these fragments recognize concave and linear epitopes. VHHs are one the best weapon for targeted drug delivery in nanomedicine and biopharmaceutics. HER2 is overexpressed in 20-25% of breast and ovarian cancers. For many reasons, HER2 is a prominent target for drug delivery to breast tumor. In this study, we designed a robust prokaryotic expression system to express functional VHHs against HER2 receptor. This system showed high recombinant yields besides purified VHHs flow cytometry verified great capabilities of these molecules to pinpoint ecto-domain of HER2 receptor in MC4L2 HER2+ while insignificant non-specific binding to MC4L2 HER2-confirm nanobodies trivial cross-reaction. In the next step, we evaluated cooperative effect of four distinctive VHHs (oligoclonal VHHs) targeting different epitopes on HER2. As our result proved, using oligoclonal nanobodies as targeting moiety enhance targeting efficacy in comparison with monoclonal VHH.