Bioengineered bacterial outer membrane vesicles encapsulated Polybia–mastoparan I fusion peptide as a promising nanoplatform for bladder cancer immune-modulatory chemotherapy

Abstract

BackgroundNanosized bacterial outer membrane vesicles (OMVs) secreted by Gram-negative bacteria have emerged as a novel antitumor nanomedicine reagent due to their immunostimulatory properties. The encapsulated bacterial composition in OMVs can be edited via manipulating bioengineering technology on paternal bacteria, allowing us to design an ingenious antitumor platform by loading the Polybia–mastoparan I (MPI) fusion peptide into OMVs.MethodsOMVs containing the MPI fusion peptide were obtained from bioengineered Escherichia coli transformed with recombinant plasmid. The antitumor efficacy of bioengineered OMVs in vitro was verified by performing cell viability and wound-healing and apoptosis assays using MB49 and UMUC3 cells, respectively. Subcutaneous MB49 tumor-bearing mice were involved to investigate the tumor inhibition ability of bioengineered OMVs. Moreover, the activated immune response in tumor and the biosafety were also evaluated in detail.ResultsThe resulting OMVs had the successful encapsulation of MPI fusion peptides and were subjected to physical characterization for morphology, size, and zeta potential. Cell viabilities of bladder cancer cells including MB49 and UMUC3 rather than a non-carcinomatous cell line (bEnd.3) were decreased when incubated with bioengineered OMVs. In addition, bioengineered OMVs restrained migration and induced apoptosis of bladder cancer cells. With intratumor injection of bioengineered OMVs, growths of subcutaneous MB49 tumors were significantly restricted. The inherent immunostimulation of OMVs was demonstrated to trigger maturation of dendritic cells (DCs), recruitment of macrophages, and infiltration of cytotoxic T lymphocytes (CTLs), resulting in the increased secretion of pro-inflammatory cytokines (IL-6, TNF-α, and IFN-γ). Meanwhile, several lines of evidence also indicated that bioengineered OMVs had satisfactory biosafety.ConclusionBioengineered OMVs fabricated in the present study were characterized by strong bladder cancer suppression and great biocompatibility, providing a new avenue for clinical bladder cancer therapy.

Staphylococcus Aureus Membrane Vesicles Kill Tumor Cells Through a Caspase-1-Dependent Pyroptosis Pathway

“…The results showed that LDH release increased in a dose-dependent manner after treatment with different concentrations of the MVs ( Figure 3C and D ). However, the non-carcinomatous cell line bEnd.3, which was generated from mouse brain microvascular endothelial cells, 14 was resistant to MV killing at different times after treatment with 20 μg/mL MV ( Figures 3E, F , and Supplementary Figure 4C ). These data indicate that S. aureus MVs can directly kill tumor cells, and that their antitumor activity is specific.…”

“…These data are consistent with the findings of a recent study, in which E. coli OMVs engineered using Polybia–mastoparan I fusion peptides presented selective tumor-killing activity. 14 S. aureus MVs can package an array of prototypic pore-forming toxins, including alpha-hemolysin, delta-hemolysin, and leukocidins. 28 , 36 However, the selective cytotoxicity of S. aureus MVs against tumor cells is unclear.…”

“… 11 , 12 OMVs produced by the E. coli strain ATCC 11775 exhibit unique antitumor efficiency in BALB/c nude mice with SK-N-SH neuroblastoma. 13 Ren et al 14 designed an ingenious antitumor nanoparticle by loading the Polybia–mastoparan I into E. coli (BL21) OMVs and found the chimeric peptide-encapsulated OMVs can suppress bladder cancer cells (MB49 and UMUC3) in vitro and in vivo. Therefore, bacterial MVs provide a novel avenue for clinical antitumor management.…”

Exosome-based delivery strategies for tumor therapy: an update on modification, loading, and clinical application

“…(3) Existing isolation techniques can only produce small amounts of exosomes, which are costly to produce on a large scale [ 216 ]. Factors such as stimulation of cells to secrete more exosomes (e.g., regulation of intracellular calcium levels, external stress, cytoskeletal blockade, drug effects, and gene expression [ 49 ]), development of more efficient isolation and purification methods (e.g., tangential flow filtration [ 217 ], asymmetrical flow field-flow fractionation [ 218 ]) or exploring new sources of exosomes (e.g., milk [ 219 ], bacteria [ 220 ], plants [ 221 ], etc.) could help to address this problem.…”

Engineered bacterial outer membrane vesicles: a versatile bacteria-based weapon against gastrointestinal tumors

“…Except for internal drug loading, a small number of drugs can be genetically engineered onto the surface of OMVs. As the study reported by Ren et al ., Polybia-mastoparan I, which exhibits preferential toxicity to tumor cells while having little damage to nontumorigenic cells, has been engineered onto OMVs surface with enhanced anti-tumor immune responses 91 .…”