Nile Tilapia Derived Antimicrobial Peptide TP4 Exerts Antineoplastic Activity Through Microtubule Disruption

Abstract

Some antimicrobial peptides (AMPs) exhibit anti-cancer activity, acting on cancer cells either by causing membrane lysis or via intracellular effects. While intracellular penetration of AMPs has been shown to cause cancer cell death, the mechanisms of toxicity remain largely unknown. Here we show that a tilapia-derived AMP, Tilapia piscidin (TP) 4, penetrates intracellularly and targets the microtubule network. A pull-down assay identified α-Tubulin as a major interaction partner for TP4, and molecular docking analysis suggested that Phe1, Ile16, and Arg23 on TP4 are required for the interaction. TP4 treatment in A549 cells was found to disrupt the microtubule network in cells, and mutation of the essential TP4 residues prevented microtubule depolymerization in vitro. Importantly, the TP4 mutants also showed decreased cytotoxicity in A549 cells, suggesting that microtubule disruption is a major mechanistic component of TP4-mediated death in lung carcinoma cells.

Antimicrobial Peptide TP4 Targets Mitochondrial Adenine Nucleotide Translocator 2

“…Moreover, other non-lytic pathogen-killing pathways, which involve the targeting of specific cellular factors, have also been reported [ 6 ]. Interestingly, some pathogen-killing activities may also allow AMPs to target cancer cells, and several AMPs have been implicated as promising anticancer agents for various cancers [ 7 , 8 , 9 , 10 , 11 , 12 ]. One such AMP, Tilapia piscidin (TP) 4, was identified in Nile tilapia ( Oreochromis niloticus ) [ 13 ].…”

“…One such AMP, Tilapia piscidin (TP) 4, was identified in Nile tilapia ( Oreochromis niloticus ) [ 13 ]. A growing body of literature has shown that a synthesized active segment of TP4 has broad-spectrum antibacterial activities [ 13 , 14 , 15 ] as well as excellent cancer cell-killing activity in different cancer types in vitro and in vivo [ 9 , 10 , 11 , 12 , 16 , 17 ]. Multiple anticancer mechanisms are thought to be involved in AMP-mediated cytotoxicity, including rapid cell membrane disruption at high-dose treatment [ 18 , 19 ].…”

“…Once bound to the cancer cells, some AMPs exert cytotoxicity simply through membrane lysis, thus preventing any robust development of multiple-drug resistance (MDR) [ 18 , 20 ]. However, other AMPs penetrate the cancer cells and target different organelles [ 10 , 11 , 12 , 16 , 19 , 21 , 22 ]. These actions of membrane lysis and organelle targeting can trigger either necrotic or apoptotic pathways in different cancer cell lines [ 18 ].…”

“…The activation of FOS family members was found to be caused by dysregulation of Ca 2+ homeostasis, as elimination of Ca 2+ signaling by a chelator largely reduced FOS family activation and AMP-induced necrotic death [ 11 , 12 , 16 , 17 , 19 ]. In addition, disruption of the cytoskeleton network was observed in AMP-treated cancer cells [ 10 , 12 , 23 , 24 ]. In this context, tubulin was shown to interact with TP4 by co-immunoprecipitation (IP) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) approaches [ 10 ].…”

“…In addition, disruption of the cytoskeleton network was observed in AMP-treated cancer cells [ 10 , 12 , 23 , 24 ]. In this context, tubulin was shown to interact with TP4 by co-immunoprecipitation (IP) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) approaches [ 10 ]. Thus, cytoskeletal dysregulation appears to be a major contributor to AMP-mediated anti-cancer activities.…”