Ribosome-inactivating proteins and their immunotoxins for cancer therapy: insights into the mechanism of cell death

Mercatelli, Daniele (2015) Ribosome-inactivating proteins and their immunotoxins for cancer therapy: insights into the mechanism of cell death, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Oncologia e patologia sperimentale, 27 Ciclo. DOI 10.6092/unibo/amsdottorato/6791.
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Ribosome-inactivating proteins (RIPs) are a family of plant toxic enzymes that permanently damage ribosomes and possibly other cellular substrates, thus causing cell death involving different and still not completely understood pathways. The high cytotoxic activity showed by many RIPs makes them ideal candidates for the production of immunotoxins (ITs), chimeric proteins designed for the selective elimination of unwanted or malignant cells. Saporin-S6, a type 1 RIP extracted from Saponaria officinalis L. seeds, has been extensively employed to construct anticancer conjugates because of its high enzymatic activity, stability and resistance to conjugation procedures, resulting in the efficient killing of target cells. Here we investigated the anticancer properties of two saporin-based ITs, anti-CD20 RTX/S6 and anti-CD22 OM124/S6, designed for the experimental treatment of B-cell NHLs. Both ITs showed high cytotoxicity towards CD20-positive B-cells, and their antitumor efficacy was enhanced synergistically by a combined treatment with proteasome inhibitors or fludarabine. Furthermore, the two ITs showed differencies in potency and ability to activate effector caspases, and a different behavior in the presence of the ROS scavenger catalase. Taken together, these results suggest that the different carriers employed to target saporin might influence saporin intracellular routing and saporin-induced cell death mechanisms. We also investigated the early cellular response to stenodactylin, a recently discovered highly toxic type 2 RIP representing an interesting candidate for the design and production of a new IT for the experimental treatment of cancer.

Tipologia del documento
Tesi di dottorato
Mercatelli, Daniele
Dottorato di ricerca
Scuola di dottorato
Scienze biologiche, biomediche e biotecnologiche
Settore disciplinare
Settore concorsuale
Parole chiave
Ribosome-inactivating proteins immunotoxins stenodactylin saporin RIP gene expression microarray mitogen-activated protein kinase MAPK bortezomib fludarabine fludara MG-132 PS 341 non-hodgkin lymphoma acute myeloid leukemia
Data di discussione
11 Maggio 2015

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