In vitro effects and ex vivo binding of an EGFR-specific immunotoxin on rhabdomyosarcoma cells

Abstract

This is the first study showing the promising therapeutic potential of a recombinant, EGFR-targeting, ETA'-based IT on RMS cells. We confirmed the selective killing with IC50 values of up to 50 pM, and immunohistochemical staining confirmed the specific ex vivo binding to primary RMS material.

Novel EGFR-specific immunotoxins based on panitumumab and cetuximab show in vitro and ex vivo activity against different tumor entities

“…Many groups use ETA-based ITs, including some that target EGFR (Azemar et al 2000;Chandramohan and Bigner 2013;Nachreiner et al 2008;Schwenkert et al 2008;Stein et al 2010;Wolf et al 2006). We have recently shown that the EGFR-specific IT 425(scFv)-ETAʹ is effective in vitro, ex vivo and in vivo, which is why we chose this construct and its corresponding 425(scFv)-SNAP fusion protein as internal references in our experiments (Bruell et al 2003(Bruell et al , 2005Hussain et al 2011;Kampmeier et al 2009Kampmeier et al , 2010Niesen et al 2014;Pardo et al 2012). Several recombinant scFv-ETA-based ITs are currently undergoing clinical evaluation, some of which target members of the EGFR family (Becker and Benhar 2012;Kreitman 2006;Schrama et al 2006).…”

“…Preclinical studies suggest that this construct could eventually be used for treatment of brain tumors Chandramohan and Bigner 2013). Promising results have also been reported for the EGFR-specific IT 425(scFv)-ETA′, which showed activity against pancreatic and epidermoid cancer cells in vitro and in vivo and also more recently against RMS cells in vitro and ex vivo (Bruell et al 2003(Bruell et al , 2005Niesen et al 2014;Pardo et al 2012). This IT was therefore used as an internal reference in the experiments described herein.…”

“…Formalin-fixed, paraffin-embedded (FFPE) tissue sections were treated to remove paraffin as described elsewhere (Niesen et al 2014). Circles were painted around each section using a Dako-pen (Dako, Hamburg, Germany).…”

Phage display-based on-slide selection of tumor-specific antibodies on formalin-fixed paraffin-embedded human tissue biopsies

“…We therefore tested the internalization behavior of the three scFv-Fc fusion proteins 3B, 3E and 6E by flow cytometry and confocal microscopy, as described previously [36]. DMS 273 cells were incubated with the fusion proteins for 30 min at 4 • C. After washing, the cells were incubated at 37 • C for 15, 30, 60, 120 and 240 min to allow internalization, and then they were detected with an FITC-labeled goat anti-mouse secondary antibody.…”

Inhibitory Effects of Resveratrol on the Human Alveolar Rhabdomyosarcoma Cell Line PLA-802 through Inhibition of the TGF-β1/Smad Signaling Pathway

“…It is well known that RMS can express various growth factors, including insulin-like growth factor [22] , basic fibroblast growth factor [23] , epidermal growth factor [24] and TGF-β [8] , which are likely involved in RMS tumorigenesis and tumor progression. A better understanding of how these growth factors modulate proliferation and apoptosis of cancer cells may ultimately have implications for the treatment of RMS.…”