Targeting claudin-overexpressing thyroid and lung cancer by modified Clostridium perfringens enterotoxin

Mol Oncol. 2020 Feb;14(2):261-276. doi: 10.1002/1878-0261.12615. Epub 2020 Jan 8.


Clostridium perfringens enterotoxin (CPE) can be used to eliminate carcinoma cells that overexpress on their cell surface CPE receptors - a subset of claudins (e.g., Cldn3 and Cldn4). However, CPE cannot target tumors expressing solely CPE-insensitive claudins (such as Cldn1 and Cldn5). To overcome this limitation, structure-guided modifications were used to generate CPE variants that can strongly bind to Cldn1, Cldn2 and/or Cldn5, while maintaining the ability to bind Cldn3 and Cldn4. This enabled (a) targeting of the most frequent endocrine malignancy, namely, Cldn1-overexpressing thyroid cancer, and (b) improved targeting of the most common cancer type worldwide, non-small-cell lung cancer (NSCLC), which is characterized by high expression of several claudins, including Cldn1 and Cldn5. Different CPE variants, including the novel mutant CPE-Mut3 (S231R/S313H), were applied on thyroid cancer (K1 cells) and NSCLC (PC-9 cells) models. In vitro, CPE-Mut3, but not CPEwt, showed Cldn1-dependent binding and cytotoxicity toward K1 cells. For PC-9 cells, CPE-Mut3 improved claudin-dependent cytotoxic targeting, when compared to CPEwt. In vivo, intratumoral injection of CPE-Mut3 in xenograft models bearing K1 or PC-9 tumors induced necrosis and reduced the growth of both tumor types. Thus, directed modification of CPE enables eradication of tumor entities that cannot be targeted by CPEwt, for instance, Cldn1-overexpressing thyroid cancer by using the novel CPE-Mut3.

Keywords: Clostridium perfringens enterotoxin; claudins; directed mutagenesis; lung cancer; necrosis; thyroid cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Antineoplastic Agents / therapeutic use
  • Carcinoma, Non-Small-Cell Lung / drug therapy
  • Carcinoma, Non-Small-Cell Lung / metabolism
  • Carcinoma, Non-Small-Cell Lung / therapy
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Claudin-1 / chemistry
  • Claudin-1 / genetics
  • Claudin-1 / metabolism
  • Claudin-3 / chemistry
  • Claudin-3 / genetics
  • Claudin-3 / metabolism
  • Claudin-4 / chemistry
  • Claudin-4 / genetics
  • Claudin-4 / metabolism
  • Claudin-5 / chemistry
  • Claudin-5 / genetics
  • Claudin-5 / metabolism
  • Claudins / chemistry
  • Claudins / genetics
  • Claudins / metabolism*
  • Clostridium perfringens / metabolism*
  • Enterotoxins / chemistry
  • Enterotoxins / pharmacology*
  • Enterotoxins / therapeutic use
  • Female
  • Humans
  • Immunohistochemistry
  • Lung Neoplasms / drug therapy*
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / therapy
  • Mice
  • Mutagenesis, Site-Directed
  • Mutation
  • Necrosis / chemically induced
  • Protein Binding
  • Recombinant Proteins
  • Thyroid Neoplasms / drug therapy*
  • Thyroid Neoplasms / metabolism
  • Thyroid Neoplasms / therapy
  • Transfection
  • Xenograft Model Antitumor Assays


  • Antineoplastic Agents
  • CLDN1 protein, human
  • CLDN3 protein, human
  • CLDN4 protein, human
  • CLDN5 protein, human
  • Claudin-1
  • Claudin-3
  • Claudin-4
  • Claudin-5
  • Claudins
  • Enterotoxins
  • Recombinant Proteins
  • enterotoxin, Clostridium