Novel Clostridium perfringens enterotoxin suicide gene therapy for selective treatment of claudin-3- and -4-overexpressing tumors

Abstract

Bacterial toxins are known to be effective for cancer therapy. Clostridium perfringens enterotoxin (CPE) is produced by the bacterial Clostridium type A strain. The transmembrane proteins claudin-3 and -4, often overexpressed in numerous human epithelial tumors (for example, colon, breast, pancreas, prostate and ovarian), are the targeted receptors for CPE. CPE binding to them triggers formation of membrane pore complexes leading to rapid cell death. In this study, we aimed at selective tumor cell killing by CPE gene transfer. We generated expression vectors bearing the bacterial wild-type CPE cDNA (wtCPE) or translationoptimized CPE (optCPE) cDNA for in vitro and in vivo gene therapy of claudin-3-and -4-overexpressing tumors. The CPE expression analysis at messenger RNA and protein level revealed more efficient expression of optCPE compared with wtCPE. Expression of optCPE showed rapid cytotoxic activity, hightened by CPE release as bystander effect. Cytotoxicity of up to 100% was observed 72 h after gene transfer and is restricted to claudin-3-and -4-expressing tumor lines. MCF-7 and HCT116 cells with high claudin-4 expression showed dramatic sensitivity toward CPE toxicity. The claudin-negative melanoma line SKMel-5, however, was insensitive toward CPE gene transfer. The non-viral intratumoral in vivo gene transfer of optCPE led to reduced tumor growth in MCF-7 and HCT116 tumor-bearing mice compared with the vector-transfected control groups. This novel approach demonstrates that CPE gene transfer can be employed for a targeted suicide gene therapy of claudin-3-and -4-overexpressing tumors, leading to the rapid and efficient tumor cell killing in vitro and in vivo.

Challenging the roles of CD44 and lipolysis stimulated lipoprotein receptor in conveying Clostridium perfringens iota toxin cytotoxicity in breast cancer

“…Two studies with another bacterial toxin, Clostridium perfringens enterotoxin (CPE), reveal that CPE specifically targets claudin-overexpressing mouse NT6 fibroblasts, human colorectal adenocarcinoma (Caco-2), colon (HCT116) and mammary (MCF-7) cell lines [22,23]. The study by Walther et al utilized non-viral, intratumoral in vivo gene transfer of CPE into mice with MCF-7 and HCT116 xenografts, resulting in reduced tumor growth compared to control groups [22].…”

“…The study by Walther et al utilized non-viral, intratumoral in vivo gene transfer of CPE into mice with MCF-7 and HCT116 xenografts, resulting in reduced tumor growth compared to control groups [22]. Translational explorations of C. perfringens iota toxin as a chemotherapeutic are yet to be exploited to date.…”

“…The use of bacterial toxins for selective and efficient cancer therapeutics has been gaining attention due to recent successes in vitro and in vivo [22,23]. Bacterial toxins possess efficient cytotoxic capabilities, making them suitable candidates for gene therapeutic applications towards various cancers [24-31].…”

Bacterial vectors for imaging and cancer gene therapy: a review

“…To date, the genera of bacteria that have been exploited as gene delivery vehicles include Salmonella, Escherichia, Listeria, Clostridium and Bifidobacterium. [9][10][11][12][13][14][15][16][17] These bacteria can be delivered to the tumor via multiple routes such as intra-tumoral 1 injection, intravenous injection or in certain instances orally. Preclinical studies have shown the ability of different bacterial strains to locally produce therapeutic agents and mediate highly effective and specific therapeutic responses.…”

Mechanism of Clostridium perfringens Enterotoxin Interaction with Claudin-3/-4 Protein Suggests Structural Modifications of the Toxin to Target Specific Claudins

“…It increases paracellular permeability (10) and could be used to improve drug delivery across tissue barriers. Furthermore, CPE constructs can be used to target claudin-overexpressing tumors (11)(12)(13)(14) because deregulation of claudin expression and function is associated with tumor proliferation/growth (15). Functional domain mapping of cCPE demonstrated that Tyr 306 , Tyr 310 , Tyr 312 , and Leu 315 are involved in binding to Cld4 (16,17).…”