IL13 Fused Pseudomonas Exotoxin Targets Various Cancers In Vitro

Anticancer Res. 2021 Jul;41(7):3471-3480. doi: 10.21873/anticanres.15134.

Abstract

Background/aim: Pseudomonas exotoxin (PE) is one of the most widely used toxins in the construction of therapeutic fusion proteins in pre-clinical studies followed by phase trials. In principle, PE acts by blocking protein synthesis through catalyzing the inactivation of elongation factor-2 (EF-2). The interleukin-13 fused PE (IL13-PE) cytotoxin was previously designed to target GBM cells. In this study, the cytotoxic effects of IL13-PE were evaluated in 5 different types of cancers and the therapeutic effects were further analyzed in a lung cancer cell line, NCI-H460. Conceptually, in another lung cancer cell line (A549), IL13Rα2 was overexpressed by lentiviruses (A549-IL13Rα2) and evaluated for cytotoxic efficacy of IL13-PE.

Materials and methods: The expression profile of IL13Rα2 in different cancer cell lines was determined by RT-PCR. Secretable toxin fusion was expressed in the toxin resistant HEK-293T cell line (293T-TxR) by using a plasmid coding for IL13-PE and IRES-GFP (LV-IL13-PE-IRES/GFP). Next, the cells were shown to produce and secrete functional IL13-PE by dot blot analysis, followed by cell viability assays and cell death analysis.

Results: Upon treatment with IL13-PE, a significant decrease in cell viability was selectively demonstrated in cancer cells with cognate receptor expression. IL13-PE treatment increased the apoptotic/necrotic cell populations in the NCI-H460 cell line.

Conclusion: Our results demonstrate that IL13-PE can be a therapeutic target for tumors bearing mostly IL13Rα2 positive cell populations. Our findings also suggest a cell-based delivery option for the recombinant toxins in the treatment of different cancers which can provide a solution for the clinical use of toxin therapy.

Keywords: IL13; IL13Rα2; Pseudomonas exotoxin; cancer; recombinant toxin; toxin.

MeSH terms

  • A549 Cells
  • Antineoplastic Agents / pharmacology
  • Cell Line
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Exotoxins / pharmacology*
  • HEK293 Cells
  • Humans
  • Immunotoxins / pharmacology*
  • Interleukin-13 / metabolism
  • Neoplasms / drug therapy*
  • Neoplasms / metabolism
  • Pseudomonas / metabolism*
  • Recombinant Fusion Proteins / pharmacology

Substances

  • Antineoplastic Agents
  • Exotoxins
  • Immunotoxins
  • Interleukin-13
  • Recombinant Fusion Proteins