Red blood cell-derived materials for cancer therapy: Construction, distribution, and applications

Cancer has become an increasingly important public health issue owing to its high morbidity and mortality rates. Although traditional treatment methods are relatively effective, they have limitations such as highly toxic side effects, easy drug resistance, and high individual variability. Meanwhile, emerging therapies remain limited, and their actual anti-tumor effects need to be improved. Nanotechnology has received considerable attention for its development and application. In particular, artificial nanocarriers have emerged as a crucial approach for tumor therapy. However, certain deficiencies persist, including immunogenicity, permeability, targeting, and biocompatibility. The application of erythrocyte-derived materials will help overcome the above problems and enhance therapeutic effects. Erythrocyte-derived materials can be acquired via the application of physical and chemical techniques from natural erythrocyte membranes, or through the integration of these membranes with synthetic inner core materials using cell membrane biomimetic technology. Their natural properties such as biocompatibility and long circulation time make them an ideal choice for drug delivery or nanoparticle biocoating. Thus, red blood cell-derived materials are widely used in the field of biomedicine. However, further studies are required to evaluate their efficacy, in vivo metabolism, preparation, design, and clinical translation. Based on the latest research reports, this review summarizes the biology, synthesis, characteristics, and distribution of red blood cell-derived materials. Furthermore, we provide a reference for further research and clinical transformation by comprehensively discussing the applications and technical challenges faced by red blood cell-derived materials in the treatment of malignant tumors.

6-C-Linked trehalose glycolipids signal through Mincle and exhibit potent adjuvant activity

Many studies have investigated the Mincle-mediated agonist activity of α,α'-trehalose-6,6́-glycolipids, however, none have considered how the position, or absence, of the ester moiety influences Mincle-mediated agonist activity. We prepared a variety of 6-C-linked α,α'-trehalose glycolipids containing inverted esters, ketone, carboxy or no carbonyl moieties. Modelling studies indicated that these derivatives bind to the CRD of Mincle in a manner similar to that of the prototypical Mincle agonist, trehalose dibehenate (TDB), with NFAT-GFP reporter cell assays confirming that all compounds, apart from derivatives with short alkyl chains, led to robust Mincle signalling. It was also observed that a carbonyl moiety was needed for good Mincle-mediated signalling. The ability of the compounds to induce mIL-1 β and mIL-6 production by bone marrow-derived macrophages (BMDMs) further demonstrated the agonist activity of the compounds, with the presence of a carbonyl moiety and longer lipid chains augmenting cytokine production. Notably, a C20 inverted ester led to levels of mIL-1β that were significantly greater than those induced by TDB. The same C20 inverted ester also led to a significant increase in hIL-1β and hIL-6 by human monocytes, and exhibited no toxicity, as demonstrated using BMDMs in an in vitro Sytox Green assay. The ability of the inverted ester to enhance antigen-mediated immune responses was then determined. In these studies, the inverted ester was found to augment the OVA-specific Th1/Th7 immune response in vitro, and exhibit adjuvanticity that was better than that of TDB in vivo, as evidenced by a significant increase in IgG antibodies for the inverted ester but not TDB when using OVA as a model antigen.

Lipophilic glucose monoesters and glycosides are potent human Mincle agonists

Macrophage inducible C-type lectin (Mincle) is a pattern recognition receptor on myeloid cells that represents a promising target for Th1-stimulating adjuvants. We report on the synthesis of branched and aromatic...

Amide-linked brartemicin glycolipids exhibit Mincle-mediated agonist activity in vitro

Lipidated derivatives of the natural product brartemicin show much promise as vaccine adjuvants due to their ability to signal through the Macrophage Inducible C-type Lectin (Mincle). We synthesised three lipophilic amide-linked brartemicin derivatives and compared their agonist activity to that of their ester-linked counterparts in vitro. We demonstrate that the brartemicin amide derivatives activate bone-marrow-derived macrophages (BMDMs) in a Mincle-dependent manner, as evidenced by the production of the pro-inflammatory cytokine IL-1β in wildtype but not Mincle^-/- cells. The amide derivatives showed activity that was as good as, if not better than, their ester counterparts. Two of the amide derivatives, but none of the ester-derivatives, also led to the production of IL-1β by human-derived monocytes. As the production of IL-1β is a good indicator of vaccine adjuvanticity potential, these findings suggest that amide-linked brartemicin derivatives show particular promise as vaccine adjuvants.

Cholesteryl glucosides signal through the carbohydrate recognition domain of the macrophage inducible C-type lectin (mincle)

Cholesteryl α-d-glucosides (αGCs) are unique metabolic products of the cancer-causing human pathogen Helicobacter pylori. Via signalling through the Macrophage inducible C-type lectin (Mincle) and the induction of a pro-inflammatory response, they are thought to play a role in the development of gastric atrophy. Herein, we prepared the first library of steryl d-glucosides and determined that they preferentially signal through the carbohydrate recognition domain of human Mincle, rather than the amino acid consensus motif. Lipidated steryl d-glucosides exhibited enhanced Mincle agonist activity, with C18 cholesteryl 6-O-acyl-α-d-glucoside (2c) being the most potent activator of human monocytes. Despite exhibiting strong Mincle signalling, sito- (5b) and stigmasterol glycosides (6b) led to a poor inflammatory response in primary cells, suggesting that Mincle is a potential therapeutic target for preventing H. pylori-mediated inflammation and cancer.

Disaccharide-polyethylenimine organic nanoparticles as non-toxic in vitro gene transporters and their anticancer potential

Polyethylenimines (PEIs) have been shown as efficient gene delivery vectors due to their unique properties, however, toxicity as well as non-specific interactions with the tissues/cells because of high charge density have hampered their use in clinical applications. To counter these concerns, here, we have prepared disachharide-PEI organic nanoparticles by mixing PEIs with non-reducing disaccharides, i.e. trehalose (TPONs) and sucrose (SPONs), under mild conditions. The fabricated nanoparticles were complexed with pDNA and size of these complexes was found in the range of ~130-162 nm with zeta potential ~ +8-25 mV. Further evaluation of these nanoparticles revealed that substitution of disaccharides on PEIs successfully augmented cell viability. Transfection efficiency exhibited by these complexes was significantly higher than the unmodified polymer and the standard, Lipofectamine, complexes. Fabrication of organic nanoparticles did not alter the buffering capacity considerably which was found to be instrumental during endosomal escape of the complexes. Among both the series of nanoparticles, trehalose-PEI organic nanoparticles (TPONs) exhibited greater pDNA transportation potential than sucrose-PEI organic nanoparticles (SPONs) which was also established by flow cytometric data, wherein percent cells expressing GFP was higher in case of TP/pDNA complexes as compared to SP/pDNA complexes. Interestingly, TPONs also showed promising anticancer activity on cancer cell lines i.e. Mg63, MCF-7 and HepG2. Overall, the results advocate promising potential of disaccharide-PEI organic nanoparticles as efficient gene delivery agents which can be used effectively in future gene therapy applications along with anti-cancer competence of TPONs.