Identification, characterization, and targeting of IL-4 receptor by IL-4-Pseudomonas exotoxin in mouse models of anaplastic thyroid cancer

Discov Med. 2015 Nov;20(111):273-84.

Abstract

Thyroid cancer is a rapidly increasing endocrine cancer. Since interleukin-4 receptor (IL-4R) is overexpressed in human solid cancer, we examined expression of IL-4R in 50 cases of anaplastic thyroid cancer (ATC), 37 well-differentiated papillary cancer (WDPC), 35 well-differentiated follicular cancer of thyroid (WDFC), and 37 normal thyroid specimens by immunohistochemistry (IHC) and in-situ hybridization (ISH) techniques. We demonstrated that IL-4Rα was overexpressed in 36/50 (72%) ATC, 20/35 (57%) WDFC, and 11/37 (30%) WDPC tumors. Other two subunits of IL-4R, interleukin-13 receptor α1 (IL-13Rα1) and interleukin-2 receptor gamma (IL-2RγC), were either weakly expressed or absent. As ATC is a highly aggressive cancer with higher incidence of IL-4Rα expression, we characterized IL-4R in 3 ATC cell lines. RT-qPCR and IFA results showed that IL-4Rα is overexpressed while IL-13Rα1 is weakly expressed. Control human umbilical vein endothelial cell line (HUVEC) showed weak expression of IL-4Rα. Binding and competition studies with 125I-IL-4 in ATC cell lines demonstrated that IL-4 specifically bound to IL-4Rα on cell surface. ATC cell lines were highly sensitive to a chimeric fusion cytotoxin consisting of circularly permuted IL-4 and truncated Pseudomonas exotoxin (IL-4-PE), which killed them in a concentration dependent manner. IL-4-PE also blocked colony formation of ATC cell lines in clonogenic assays. IL-4-PE mediated a significant antitumor activity in mouse models of ATC. Intratumoral administration of IL-4-PE caused significant regression of established tumors in a dose dependent manner and increased the overall survival without any visible toxicity. Thus, IL-4Rα in ATC may represent a novel therapeutic target and IL-4-PE may serve as an investigational therapeutic option for ATC.

MeSH terms

  • ADP Ribose Transferases / pharmacology*
  • Animals
  • Bacterial Toxins / pharmacology*
  • Cell Line, Tumor
  • Drug Delivery Systems / methods*
  • Exotoxins / pharmacology*
  • Female
  • Humans
  • Interleukin-4 / pharmacology*
  • Interleukin-4 Receptor alpha Subunit / agonists*
  • Interleukin-4 Receptor alpha Subunit / genetics
  • Interleukin-4 Receptor alpha Subunit / metabolism
  • Male
  • Mice
  • Mice, Nude
  • Neoplasm Proteins / agonists*
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism
  • Recombinant Fusion Proteins / pharmacology
  • Thyroid Neoplasms / drug therapy*
  • Thyroid Neoplasms / genetics
  • Thyroid Neoplasms / metabolism
  • Thyroid Neoplasms / pathology
  • Virulence Factors / pharmacology*
  • Xenograft Model Antitumor Assays

Substances

  • Bacterial Toxins
  • Exotoxins
  • IL4 protein, human
  • IL4R protein, human
  • Interleukin-4 Receptor alpha Subunit
  • Neoplasm Proteins
  • Recombinant Fusion Proteins
  • Virulence Factors
  • Interleukin-4
  • ADP Ribose Transferases
  • toxA protein, Pseudomonas aeruginosa