Targeted Delivery of the Mitochondrial Target Domain of Noxa to Tumor Tissue via Synthetic Secretion System in E. coli

Abstract

Targeted delivery of drugs is a key aspect of the successful treatment of serious conditions such as tumors. In the pursuit of accurate delivery with high specificity and low size limit for peptide drugs, a synthetic type 3 secretion system (T3SS) has been repurposed from a native genetic system encoded in Salmonella pathogenicity island-1 (SPI-1) with no virulence effectors. Here, we tested the potential of synthetic T3SS as drug delivery machinery for peptide-based drugs owing to its modular nature. First, the genetic system for synthetic T3SS was introduced into non-native host E. coli, which was chosen for its lack of Salmonella-driven virulence factors. Next, the mitochondrial targeting domain (MTD) of Noxa was tested as a cargo protein with anti-tumor activity. To this end, the gene encoding MTD was engineered for secretion through synthetic T3SS, thereby resulting in the tagged MTD at the N-terminus. When E. coli carrying synthetic T3SS and MTD on plasmids was administered into tumor-bearing mice, MTD with a secretion tag at the N-terminus was clearly detected in the tumor tissue after induction. Also, the tumor growth and mortality of tumor-bearing animals were mitigated by the cytotoxic activity of the delivered. Thus, this work potentiates the use of biotherapeutic bacteria for the treatment of tumors by implanting a dedicated delivery system.

Mitochondrial adaptation in cancer drug resistance: prevalence, mechanisms, and management

“…In recent years, numerous drug delivery systems, including liposomes, micelles, “smart” polymers, and hydrogels, have been developed for cancer therapy [ 547 – 552 ]. For instance, to achieve accurate delivery to mitochondria with high specificity and low size, a native genetic system encoded in Salmonella pathogenicity island-1 (SPI-1) was used by Lim et al [ 553 ]. In their study, E. coli carrying synthetic T3SS and MTD on plasmids could eliminate tumors and reduce the mortality of tumor-bearing animals.…”

Secretion of functional interferon by the type 3 secretion system of enteropathogenic Escherichia coli

“…However, since the secreted proteins must unfold during their translocation through the T3SS conduit, it is critical to determine, for each therapeutic protein, its ability to refold in the extracellular space and regain its biological activity [ 63 ]. Furthermore, while the potential of this system is thought to be enormous, only a few studies have actually employed it to deliver potentially therapeutic proteins [ 58 , 64 , 65 ]. In this study, we present promising results that IFN, which belongs to a large family of immune-modulatory proteins, can be secreted by the T3SS of EPEC while remaining functional, opening up new avenues for oral delivery of IFN by secreting bacteria.…”

N-terminal toxin signal peptides efficiently load therapeutics into a natural nano-injection system

“…Targeted delivery in biotechnology and biomedicine aims to deliver effectors and drugs directly into specific cells while minimizing off-target effects. Bacterial nano-injection systems such as T6SS and T3SS as well as the eCIS PVC, have shown their potential for efficient delivery and modulation of host cell pathways (4–6, 15, 45, 46). However, several challenges remain, including effector loading, studies in animal models, and strain and payload activity in vivo ( 48, 49 ).…”

“…Membrane-bound contractile injection systems (CIS), such as the T6SS and Type III Secretion Systems (T3SS), have been engineered to deliver toxins or proteins through host membranes (4)(5)(6). Potential drawbacks of these systems are their cell envelope-bound state, therefore a limiting factor for large scale production, the need to generate toxic bacterial strains, and an upper size limit of non-eCIS related proteins for translocation (7).…”