Anticorps monoclonaux à usage thérapeutique : un peu d'histoire, beaucoup d'ingénierie, et … quelques succès cliniques

Targeting MCF-7 Cell Line by Listeriolysin O Pore Forming Toxin Fusion with AHNP Targeted Peptide

Background

Tumor-targeting peptides are attracting subjects in cancer therapy. These peptides, which are widely studied, deliver therapeutic agents to the specific sites of tumors. In this study, we produced a new form of recombinant listeriolysin O (LLO) with genetically fused Anti-HER2/neu peptide (AHNP) sequence adding to its C-terminal end. The aim of the study was to engineer this pore-forming toxin to make it much more specific to tumor cells.

Materials and Method and Results

Two forms of the toxin (with and without peptide) were subcloned into a bacterial expression plasmid. Subcloning was performed using a polymerase chain reaction (PCR) product as a megaprimer in a quick-change PCR to introduce the whole insert gene into the expression plasmid. After expression of two recombinant forms of LLO in BL21 DE3 cells, purification was performed using Ni-NTA affinity column. MDA-MB-231 and MCF-7 cell lines (as negative and positive controls, respectively) were treated with both LLO toxins to evaluate their cytotoxicity and specificity. The IC₅₀ of LLO on MDA-MB-231 and MCF-7 cells was 21 and 5 ng/ml, respectively. In addition, IC₅₀ for the fusion AHNP-LLO toxin was 140 and 60 ng/ml, respectively. It was found that the cytotoxicity of the new engineered AHNP-LLO toxin has decreased by about 9x compared to the wild-type toxin and the specificity of the AHNP-LLO toxin has been also reduced.

Conclusions

Results show that the C-terminal of the LLO should not be modified and it seems that N-terminal of the toxin should be preferred for engineering and adding peptide modules.

Adverse effects of the humanized antibodies used as cancer therapeutics

PURPOSE OF REVIEW

Humanized monoclonal antibodies represent a recent and very significant addition to the anticancer armamentarium. With improved therapeutic strategies due to these agents, however, there are also various, sometimes unexpected, side effects.

RECENT FINDINGS

Most of the monoclonal antibodies used in oncology share a risk of infusion-related manifestations, including the possibility of anaphylaxis; these reactions usually appear early on during the first administration. Hematological toxicity is also frequent, especially if the antibodies are associated with chemotherapy; the resulting neutropenia--and with some agents lymphopenia--is associated with an increased risk of infection. Cardiac failure and pulmonary complications have been reported with some of these agents, especially in patients with prior cardiac or pulmonary comorbidities.

SUMMARY

Although consideration of these side effects is important in terms of prevention and therapy, overall they are relatively uncommon, making therapy with monoclonal antibodies quite safe in comparison with other therapeutic modalities used in cancer patients.