Resurfacing receptor binding domain of Colicin N to enhance its cytotoxic effect on human lung cancer cells

Wanatchaporn Arunmanee; Methawee Duangkaew; Pornchanok Taweecheep; Kanokpol Aphicho; Panuwat Lerdvorasap; Jesada Pitchayakorn; Chayada Intasuk; Runglada Jiraratmetacon; Armini Syamsidi; Pithi Chanvorachote; Chatchai Chaotham; Natapol Pornputtapong

doi:10.1016/j.csbj.2021.09.008

Resurfacing receptor binding domain of Colicin N to enhance its cytotoxic effect on human lung cancer cells

Comput Struct Biotechnol J. 2021 Sep 14:19:5225-5234. doi: 10.1016/j.csbj.2021.09.008. eCollection 2021.

Authors

Affiliations

¹ Department of Biochemistry and Microbiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand.
² Department of Pharmacy, Faculty of Science, Tadulako University, Central Sulawesi 94118, Indonesia.
³ Department of Pharmacology and Physiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand.
⁴ Cell-based Drug and Health Products Development Research Unit, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand.
⁵ Center of Excellence in Systems Biology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.

Abstract

Colicin N (ColN) is a bacteriocin secreted by Escherichia coli (E. coli) to kill other Gram-negative bacteria by forcefully generating ion channels in the inner membrane. In addition to its bactericidal activity, ColN have been reported to selectively induce apoptosis in human lung cancer cells via the suppression of integrin modulated survival pathway. However, ColN showed mild toxicity against human lung cancer cells which could be improved for further applications. The protein resurfacing strategy was chosen to engineer ColN by extensive mutagenesis at solvent--exposed residues on ColN. The highly accessible Asp and Glu on wild-type ColN (ColN^WT) were replaced by Lys to create polycationic ColN (ColN⁺¹²). Previous studies have shown that increase of positive charges on proteins leads to the enhancement of mammalian cell penetration as well as increased interaction with negatively charged surface of cancer cells. Those solvent--exposed residues of ColN were identified by Rosetta and AvNAPSA (Average number of Neighboring Atoms Per Side-chain Atom) approaches. The findings revealed that the structural features and stability of ColN⁺¹² determined by circular dichroism were similar to ColN^WT. Furthermore, the toxicity of ColN⁺¹² was cancer -selective. Human lung cancer cells, H460 and H23, were sensitive to ColN but human dermal papilla cells were not. ColN⁺¹² also showed more potent toxicity than ColN^WT in cancer cells. This confirmed that polycationic resurfacing method has enabled us to improve the anticancer activity of ColN towards human lung cancer cells.

Keywords: Anticancer; Colicin; Pore forming toxin; Protein resurfacing.