Design of NK‐2‐derived peptides with improved activity against equine sarcoid cells

Abstract

Equine sarcoid is a topically accessible model for the evaluation of anticancer peptides acting by physical membrane disruption avoiding the complexity of a systemic application. We aim at evaluating and improving natural peptides for host defence as lead structures, where we focus on the cationic and amphipathic peptide NK-2. Cytotoxicity tests, fluorescence microscopy and a chip-based biosensor, which enabled real-time monitoring of cell metabolism, were applied. Cancer cell killing was dynamic with an initial phase of increased cellular respiration, followed by membrane destruction. NK-2 was substantially improved and shortened. Novel peptides exhibited a fivefold improved activity against sarcoid cells, while haemolysis remained almost unaltered. Similar Zeta potential and similar amount of surface phosphatidylserine of sarcoid and normal skin cells are responsible for a lack of selectivity between these two cell types.

Host defense peptides for treatment of colorectal carcinoma - a comparative in vitro and in vivo analysis

“…Peptides (C7A, C7A-D21K, C7A-Δ), and NK11 used in this study were based on NK-2 (Table 2 and [17]). The most basic modification entailed replacement of the non-functional sole Cys7 residue within the NK-2 sequence with an Ala residue (C7A).…”

“…The most basic modification entailed replacement of the non-functional sole Cys7 residue within the NK-2 sequence with an Ala residue (C7A). This substitution has been shown to improve anti-cancer cell activity of the lead structure NK-2 [17]. An enhancement of C7A's positive net charge was achieved by substituting Asp21 by a Lys residue (C7A-D21K).…”

“…HDPs applied in this study were based on NK-2, a porcine immune cell-derived peptide, whose selective killing of different human cancer lines is well established [10]. NK-2 derivatives exhibit reduced sensitivity towards oxidation, show improved antibacterial and –most importantly– oncolytic activity [17]. …”

“…This feature clearly distinguishes malignant from normal cells and provides a rationale for HDP-based tumor therapy [15,16]. For that reason, this study aimed at testing the oncolytic potential of NK-2-based HDPs [17] against patient-derived colorectal cancer (CRC) cell lines in order to pave the way for further treatment optimizations based on these peptides.…”

Comparison of patient-derived high and low phosphatidylserine-exposing colorectal carcinoma cells in their interaction with anti-cancer peptides

“…However, such mechanisms would have likewise impeded the activity of any peptide tested here, which in fact was not observed. Instead, based on recent and previous findings , it may be concluded that the cysteine‐to‐alanine substitution at position 7 was key to the sustained activity in medium, most likely via reducing the risk of side chain oxidation, thus, enhancing peptide stability.…”