Doxorubicin-loaded bacterial outer-membrane vesicles exert enhanced anti-tumor efficacy in non-small-cell lung cancer

Abstract

More efficient drug delivery system and formulation with less adverse effects are needed for the clinical application of broad-spectrum antineoplastic agent doxorubicin (DOX). Here we obtained outer-membrane vesicles (OMVs), a nano-sized proteoliposomes naturally released by Gram-negative bacteria, from attenuated Klebsiella pneumonia and prepared doxorubicin-loaded O0MVs (DOX-OMV). Confocal microscopy and in vivo distribution study observed that DOX encapsulated in OMVs was efficiently transported into NSCLC A549 cells. DOX-OMV resulted in intensive cytotoxic effects and cell apoptosis in vitro as evident from MTT assay, Western blotting and flow cytometry due to the rapid cellular uptake of DOX. In A549 tumor-bearing BALB/c nude mice, DOX-OMV presented a substantial tumor growth inhibition with favorable tolerability and pharmacokinetic profile, and TUNEL assay and H&E staining displayed extensive apoptotic cells and necrosis in tumor tissues. More importantly, OMVs’ appropriate immunogenicity enabled the recruitment of macrophages in tumor microenvironment which might synergize with their cargo DOX in vivo . Our results suggest that OMVs can not only function as biological nanocarriers for chemotherapeutic agents but also elicit suitable immune responses, thus having a great potential for the tumor chemoimmunotherapy.

Extracellular Vesicles: An Overlooked Secretion System in Cyanobacteria

“…As EVs were loaded with a small interfering RNA (siRNA), the specificity of the EVs’ delivery resulted in targeted gene silencing, and thus in a reduction in the protein levels of a key enzyme involved in mitosis, ultimately inhibiting cancer cell proliferation [ 105 ]. Moreover, these nanostructures have also revealed their great potential in the delivery of chemotherapeutic agents, as demonstrated with EVs from an attenuated Klebsiella pneumonia strain that efficiently delivered the drug doxorubicin to lung cancer cells [ 106 ]. Moreover, in the context of cancer, EVs have also been reported as a promising tool for immunotherapy strategies, not only through EV-induced long-term antitumor immune responses [ 114 ], but also through their decoration with tumor antigens towards antigen-specific antitumor therapy [ 115 ].…”

“…The best example is perhaps the use of EVs in vaccination, for which the commercial vaccine Bexsero ® is a case of widely accepted success. Bacterial EVs have also been tested with promising results to deliver cargo in a cell-specific manner, in particular in the context of cancer research (e.g., [ 105 , 106 ]). EVs from the cyanobacterium Synechococcus elongatus PCC 7942 have been shown to positively modulate and even promote angiogenesis in the context of wound healing.…”

Natural Ingredient-Based Polymeric Nanoparticles for Cancer Treatment

“…The vesicles exerted intensive cytotoxic effects of A549 cells as the OMVs entered the A549 cells efficiently. The doxorubicin-loaded OMVs also suppressed the tumor growth in A549 tumor-bearing BALB/c nude mice with good tolerability and pharmacokinetic profile as compared to free doxorubicin [126]. When using genetically modified OMVs as a cancer immunotherapeutic agent, it was reported that interferon-γ dependent antitumor effect was induced due to the accumulation of OMVs in the tumor tissue.…”

Nanomedicine in lung cancer: Current states of overcoming drug resistance and improving cancer immunotherapy

“…in vivo distribution study showed that DOX encapsulated in OMVs was efficiently transported into NSCLC A549 cells and induced a substantial inhibition of tumor growth. In addition, OMVs enabled the recruitment of macrophages in TME and elicited immune responses (Kuerban et al, 2020).…”