Transferrin receptor-mediated liposomal drug delivery: recent trends in targeted therapy of cancer

Peptide-based inhibitors and nanoparticles: Emerging therapeutics for Alzheimer's disease

Alzheimer's disease (AD) is an age-related progressive neurodegenerative disorder characterized by memory loss, cognitive decline, and behavioral changes, impacting millions of individuals worldwide. Despite significant research into its cellular and molecular mechanisms, no cure has been found to treat AD to date. For over two decades, research aimed at treating AD has focused on targeting amyloid-β (Aβ); however, these strategies have not demonstrated substantial effectiveness. Consequently, research is now expanding towards targeting other hallmarks of the disease, such as tau protein and brain metal ions. Among potential therapeutics against these pathophysiological targets, peptide-based inhibitors are notable for their high selectivity and low toxicity. Despite these advantages, they face obstacles such as a short half-life in vivo and low efficiencies in crossing the blood-brain barrier (BBB). The use of nanoparticles (NPs) to deliver peptide-based inhibitors to the brain offers unique advantages, such as enhanced stability against degradation, improvement in targeted delivery, and reduced potential for immunogenic responses. This review aims to provide a comprehensive overview of emerging peptides tested as treatments for AD against Aβ, tau protein, and brain metal ions and to evaluate NPs as a means to overcome the limitations. These peptide-based inhibitors are promising, as they not only alleviate symptoms but also aim to prevent progressive neuronal loss, and NPs can be highly effective in delivering these inhibitors.

Targeted Covalent Nanodrugs Reinvigorate Antitumor Immunity and Kill Tumors via Improving Intratumoral Accumulation and Retention of Doxorubicin

Specifically improving the intratumoral accumulation and retention and achieving the maximum therapeutic efficacy of small-molecule chemotherapeutics remains a considerable challenge. To address the issue, we here reported near-infrared (NIR) irradiation-activatable targeted covalent nanodrugs by installing diazirine-labeled transferrin receptor 1 (TfR1)-targeted aptamers on PEGylated phospholipid-coated upconversion nanoparticles followed by doxorubicin loading. Targeted covalent nanodrugs recognized and then were activated to covalently cross-link with TfR1 on cancer cells by 980 nm NIR irradiation. Systematic studies revealed that they achieved >6- and >5.5-fold higher intratumoral accumulations of doxorubicin than aptamer-based targeted nanodrugs at 6 and 120 h post intravenous injection, respectively. Based on high drug delivery efficacy, targeted covalent nanodrugs boosted doxorubicin-induced immunogenic cell death, activated antitumor immune responses and shrank the sizes of both primary and distant tumors, and displayed better therapeutic efficacy and less adverse effect than targeted nanodrugs and commercial Doxil in 4T1 syngeneic breast tumor model featuring an immunosuppressive microenvironment. By integrating the specificity of molecular recognition, the reactivity profile of diazirine and the accuracy of light manipulation with nanodrug supremacy, our targeted covalent nanodrugs could be expected as a longer-term and efficient strategy to improve anticancer therapeutic efficacy of chemotherapeutics.

Molecular dynamics of transferrin receptor binder peptides: unlocking blood-brain barrier for enhanced CNS drug delivery

A cystine-dense peptide (CDP) named TfRB1 was identified for its ability to bind to the transferrin receptor (TfR). CDPs are stabilized by their disulfide bonds, and variants of TfRB1 - specifically TfRB1G1, TfRB1G2, and TfRB1G3 - are explored for their potential to transport molecules across the blood-brain barrier (BBB) into the central nervous system (CNS). This study employed molecular modeling and dynamics simulations to characterize the interactions between these TfRB1 variants and TfR. Binding free energy calculations showed a strong correlation with experimental binding affinities of -10.99 kcal/mol for TfRB1G2 and -13.18 kcal/mol for TfRB1G3, with a relative error of 1.98%. The key forces driving these interactions include electrostatic and van der Waals forces, with mutations in TfRB1G3 (T9M and A13D) enhancing its binding affinity through improved interactions with residues such as Arg633. The free energy landscape analysis revealed that TfRB1G3 maintains the N-terminal residues of TfR in an α-helical conformation, unlike TfRB1G2. Per-residue free energy decomposition identified key residues - Leu619, Arg629, Tyr643, and Phe650 - as crucial for TfR binding, underscoring their competitive nature with transferrin. Additionally, Glu612, which is favorable for binding in TfRB1G2, becomes unfavorable in TfRB1G3. Conversely, Arg633 shifts from unfavorable in TfRB1G2 to favorable in TfRB1G3, compensating for the loss of favorable interaction with Glu612. These findings provide valuable molecular insights into the TfRB1 peptides' potential as drug carriers, highlighting their capability to deliver molecules to the CNS and compete with transferrin for BBB transport.

OX26-cojugated gangliosilated liposomes to improve the post-ischemic therapeutic effect of CDP-choline

Cerebrovascular impairment represents one of the main causes of death worldwide with a mortality rate of 5.5 million per year. The disability of 50% of surviving patients has high social impacts and costs in long period treatment for national healthcare systems. For these reasons, the efficacious clinical treatment of patients, with brain ischemic stroke, remains a medical need. To this aim, a liposome nanomedicine, with monosialic ganglioside type 1 (GM1), OX26 (an anti-transferrin receptor antibody), and CDP-choline (a neurotrophic drug) (CDP-choline/OX26Lip) was prepared. CDP-choline/OX26Lip were prepared by a freeze and thaw method and then extruded through polycarbonate filters, to have narrow size distributed liposomes of ~80 nm. CDP-choline/OX26Lip were stable in human serum, they had suitable pharmacokinetic properties, and 30.0 ± 4.2% of the injected drug was still present in the blood stream 12 h after its systemic injection. The post-ischemic therapeutic effect of CDP-choline/OX26Lip is higher than CDP-choline/Lip, thus showing a significantly high survival rate of the re-perfused post-ischemic rats, i.e. 96% and 78% after 8 days. The treatment with CDP-choline/OX26Lip significantly decreased the peroxidation rate of ~5-times compared to CDP-choline/Lip; and the resulting conjugated dienes, that was 13.9 ± 1.1 mmol/mg proteins for CDP-choline/Lip and 3.1 ± 0.8 for CDP-choline/OX26Lip. OX26 increased the accumulation of GM1-liposomes in the brain tissues and thus the efficacious of CDP-choline. Therefore, this nanomedicine may represent a strategy for the reassessment of CDP-choline to treat post-ischemic events caused by brain stroke, and respond to a significant clinical need.

Transferrin-Modified Carprofen Platinum(IV) Nanoparticles as Antimetastasis Agents with Tumor Targeting, Inflammation Inhibition, Epithelial-Mesenchymal Transition Suppression, and Immune Activation Properties

The inflammatory microenvironment is a central driver of tumor metastasis, intimately associated with the promotion of epithelial-mesenchymal transition (EMT) and immune suppression. Here, transferrin-modified carprofen platinum(IV) nanoparticles Tf-NPs@CPF2-Pt(IV) with promising antiproliferative and antimetastatic properties were developed, which activated by inhibiting inflammation, suppressing EMT, and activating immune responses besides causing DNA injury. The nanoparticles released the active ingredient CPF2-Pt(IV) in a sustained manner and offered enhanced pharmacokinetic properties compared to free CPF2-Pt(IV) in vivo. Additionally, they possessed satisfactory tumor targeting effects via the transferrin motif. Serious DNA damage was induced with the upregulation of γ-H2AX and P53, and the mitochondria-mediated apoptotic pathway Bcl-2/Bax/caspase3 was initiated. Inflammation was alleviated by inhibiting COX-2 and MMP9 and decreasing inflammatory cytokines TNF-α and IL-6. Subsequently, the EMT was reversed by inhibiting the Wnt/β-catenin pathway. Furthermore, the antitumor immunity was provoked by blocking the immune checkpoint PD-L1 and increasing CD3+ and CD8+ T lymphocytes in tumors.

Selective Transfection of a Transferrin Receptor-Expressing Cell Line with DNA-Lipid Nanoparticles

Despite considerable progress in using lipid nanoparticle (LNP) vehicles for gene delivery, achieving selective transfection of specific cell types remains a significant challenge, hindering the advancement of new gene or gene-editing therapies. Although LNPs have been equipped with ligands aimed at targeting specific cellular receptors, achieving complete selectivity continues to be elusive. The exact reasons for this limited selectivity are not fully understood, as cell targeting involves a complex interplay of various cellular factors. Assessing how much ligand/receptor binding contributes to selectivity is challenging due to these additional influencing factors. Nonetheless, such data are important for developing new nanocarriers and setting realistic expectations for selectivity. Here, we have quantified the selective, targeted transfection using two uniquely engineered cell lines that eliminate unpredictable and interfering cellular influences. We have compared the targeted transfection of Chinese ovary hamster (CHO) cells engineered to express the human transferrin receptor 1 (hTfR1), CHO-TRVb-hTfR1, with CHO cells that completely lack any transferrin receptor, CHO-TRVb-neo cells (negative control). Thus, the two cell lines differ only in the presence/absence of hTfR1. The transfection was performed with pDNA-encapsulating LNPs equipped with the DT7 peptide ligand that specifically binds to hTfR1 and enables targeted transfection. The LNP's pDNA encoded for the monomeric GreenLantern (mGL) reporter protein, whose fluorescence was used to quantify transfection. We report a novel LNP composition designed to achieve an optimal particle size and ζ-potential, efficient pDNA encapsulation, hTfR1-targeting capability, and sufficient polyethylene glycol sheltering to minimize random cell targeting. The transfection efficiency was quantified in both cell lines separately through flow cytometry based on the expression of the fluorescent gene product. Our results demonstrated an LNP dose-dependent mGL expression, with a 5-fold preference for the CHO-TRVb-hTfR1 when compared to CHO-TRVb-neo. In another experiment, when both cell lines were mixed at a 1:1 ratio, the DT7-decorated LNP achieved a 3-fold higher transfection of the CHO-TRVb-hTfR1 over the CHO-TRVb-neo cells. Based on the low-level transfection of the CHO-TRVb-neo cells in both experiments, our results suggest that 17-25% of the transfection occurred in a nonspecific manner. The observed transfection selectivity for the CHO-TRVb-hTfR1 cells was based entirely on the hTfR1/DT7 interaction. This work showed that the platform of two engineered cell lines which differ only in the hTfR1 can greatly facilitate the development of LNPs with hTfR1-targeting ligands.

Transferrin receptor-targeted immunostimulant for photodynamic immunotherapy against metastatic tumors through β-catenin/CREB interruption

The immunosuppressive phenotype of tumor cells extensively attenuates the immune activation effects of traditional treatments. In this work, a transferrin receptor (TfR) targeted immunostimulant (PTI) is fabricated for photodynamic immunotherapy against metastatic tumors by interrupting β-catenin signal pathway. To synthesize PTI, the photosensitizer conjugated TfR targeting peptide moiety (Palmitic-K(PpIX)-HAIYPRH) is unitized to encapsulate the transcription interrupter of ICG-001. On the one hand, the recognition of PTI and TfR can promote drug delivery into tumor cells to destruct primary tumors through photodynamic therapy and initiate an immunogenic cell death with the release of tumor-associated antigens. On the other hand, PTI will interrupt the binding between β-catenin and cAMP response element-binding protein (CREB), regulating the gene transcription to downregulate programmed death ligand 1 (PD-L1) while upregulating C-C motif chemokine ligand 4 (CCL4). Furthermore, the elevated CCL4 can recruit the dendritic cells to present tumor-specific antigens and promote T cells activation and infiltration, and the downregulated PD-L1 can avoid the immune evasion of tumor cells and activate systemic anti-tumor immunity to eradicate lung metastasis. This work may inspire the development of antibody antibody-free strategy to activate systemic immune response in consideration of immunosuppressive conditions.

Albumin Nanoparticle-Based Drug Delivery Systems

Nanoparticle-based systems are extensively investigated for drug delivery. Among others, with superior biocompatibility and enhanced targeting capacity, albumin appears to be a promising carrier for drug delivery. Albumin nanoparticles are highly favored in many disease therapies, as they have the proper chemical groups for modification, cell-binding sites for cell adhesion, and affinity to protein drugs for nanocomplex generation. Herein, this review summarizes the recent fabrication techniques, modification strategies, and application of albumin nanoparticles. We first discuss various albumin nanoparticle fabrication methods, from both pros and cons. Then, we provide a comprehensive introduction to the modification section, including organic albumin nanoparticles, metal albumin nanoparticles, inorganic albumin nanoparticles, and albumin nanoparticle-based hybrids. We finally bring further perspectives on albumin nanoparticles used for various critical diseases.

In vivo Fate of Targeted Drug Delivery Carriers

This review aimed to systematically investigate the intracellular and subcellular fate of various types of targeting carriers. Upon entering the body via intravenous injection or other routes, a targeting carrier that can deliver therapeutic agents initiates their journey. If administered intravenously, the carrier initially faces challenges presented by the blood circulation before reaching specific tissues and interacting with cells within the tissue. At the subcellular level, the car2rier undergoes processes, such as drug release, degradation, and metabolism, through specific pathways. While studies on the fate of 13 types of carriers have been relatively conclusive, these studies are incomplete and lack a comprehensive analysis. Furthermore, there are still carriers whose fate remains unclear, underscoring the need for continuous research. This study highlights the importance of comprehending the in vivo and intracellular fate of targeting carriers and provides valuable insights into the operational mechanisms of different carriers within the body. By doing so, researchers can effectively select appropriate carriers and enhance the successful clinical translation of new formulations.

Ferroptosis in Cancer Therapy: Mechanisms, Small Molecule Inducers, and Novel Approaches

Ferroptosis, a unique form of programmed cell death, is initiated by an excess of iron accumulation and lipid peroxidation-induced damage. There is a growing body of evidence indicating that ferroptosis plays a critical role in the advancement of tumors. The increased metabolic activity and higher iron levels in tumor cells make them particularly vulnerable to ferroptosis. As a result, the targeted induction of ferroptosis is becoming an increasingly promising approach for cancer treatment. This review offers an overview of the regulatory mechanisms of ferroptosis, delves into the mechanism of action of traditional small molecule ferroptosis inducers and their effects on various tumors. In addition, the latest progress in inducing ferroptosis using new means such as proteolysis-targeting chimeras (PROTACs), photodynamic therapy (PDT), sonodynamic therapy (SDT) and nanomaterials is summarized. Finally, this review discusses the challenges and opportunities in the development of ferroptosis-inducing agents, focusing on discovering new targets, improving selectivity, and reducing toxic and side effects.

Relative biomembrane fusogenicities of the tumor-selective liposomes of RGDK- and CGKRK-lipopeptides

Cancer is the second leading cause of death globally after heart diseases. Currently used highly cytotoxic anti-cancer drugs not only kill cancer cells but also often kill non-cancerous healthy body cells, causing adverse side effects. Efforts are now being directed towards developing tumor-selective chemotherapy. Tumor/tumor endothelial cell selective peptide ligands are being covalently grafted onto the exo-surfaces of drug carriers such as liposomes, polymers, etc. A number of prior studies used conjugation of tumor/tumor endothelial cell-selective RGDK- or CGKRK-peptide ligands on the outer surfaces of liposomes, metal-based nanoparticles, single walled carbon nanotubes (SWNTs), etc. However, studies aimed at examining the relative cell membrane fusogenicities and the relative degrees of cellular uptake for the RGDK- and CGKRK-ligand-grafted nanometric drug carriers have not yet been undertaken. Herein, using the widely used liposomes of DOPC, DOPE, DOPS and cholesterol (45 : 25 : 20 : 15, w/w ratio) as the model biomembranes and the fluorescence resonance energy transfer (FRET) assay for measuring membrane fusogenicities, we show that the liposomes of the RGDK-lipopeptide are more biomembrane fusogenic than the liposomes of the CGKRK-lipopeptide. Notably, such FRET assay-derived relative biomembrane fusogenicities of the liposomes of RGDK- and CGKRK-lipopeptides were found to be consistent with their relative degrees of cellular uptake in cultured cancer cells. The present findings open the door for undertaking in-depth in vivo studies aimed at evaluating the relative therapeutic potential of different nanocarriers of drugs/genes/siRNA having tumor-targeting RGDK- and CGKRK-peptides on their exo-surfaces.

New Transferrin Receptor-Targeted Peptide-Doxorubicin Conjugates: Synthesis and In Vitro Antitumor Activity

Poor selectivity to tumor cells is a major drawback in the clinical application of the antitumor drug doxorubicin (DOX). Peptide-drug conjugates (PDCs) constructed by modifying antitumor drugs with peptide ligands that have high affinity to certain overexpressed receptors in tumor cells are increasingly assessed for their possibility of tumor-selective drug delivery. However, peptide ligands composed of natural L-configuration amino acids have the defects of easy enzymatic degradation and insufficient biological stability. In this study, two new PDCs (LT7-SS-DOX and DT7-SS-DOX) were designed and synthesized by conjugating a transferrin receptor (TfR) peptide ligand LT7 (HAIYPRH) and its retro-inverso analog DT7 (hrpyiah), respectively, with DOX via a disulfide bond linker. Both conjugates exhibited targeted antiproliferative effects on TfR overexpressed tumor cells and little toxicity to TfR low-expressed normal cells compared with free DOX. Moreover, the DT7-SS-DOX conjugate possessed higher serum stability, more sustained reduction-triggered drug release characteristics, and stronger in vitro antiproliferative activity as compared to LT7-SS-DOX. In conclusion, the coupling of antitumor drugs with the DT7 peptide ligand can be used as a promising strategy for the further development of stable and efficient PDCs with the potential to facilitate TfR-targeted drug delivery.

TfR Aptamer-Functionalized MSNs for Enhancing Targeted Cellular Uptake and Therapy of Cancer Cells

Mesoporous silica nanoparticles (MSNs), as novel nanocarriers for drug delivery in cancer treatment, have attracted widespread concern because of their rich pore structure, large pore capacity, ease of modification, and biocompatibility. However, the limitation of nontargeting and low uptake efficiency hindered their further application. Considering the overexpression of the transferrin receptor (TfR) on most cancer cell membranes, herein, we propose a strategy to effectively enhance the cellular internalization of MSNs by arming them with the TfR aptamer. Cellular fluorescent imaging and flow cytometry analysis demonstrated that TfR aptamer-functionalized MSNs exhibited superior cellular internalization compared to unmodified or random sequence-modified MSNs toward three different cancer cell lines, including MCF-7, HeLa, and A549. Furthermore, TfR aptamer-functionalized MSNs displayed enhanced drug delivery efficiency compared with MSNs at equivalent doses and incubation times. These results suggested that TfR aptamer-functionalized MSNs have the potential for enhanced delivery of therapeutic agents into TfR-positive cancer cells to improve therapeutic efficacy.

Recent advances of polymeric nanoplatforms for cancer treatment: smart delivery systems (SDS), nanotheranostics and multidrug resistance (MDR) inhibition

Nanotheranostics is a promising field that combines the benefits of diagnostic and treatment into a single nano-platform that not only administers treatment but also allows for real-time monitoring of therapeutic response, decreasing the possibility of under/over-drug dosing. Furthermore, developing smart delivery systems (SDSs) for cancer theranostics that can take advantage of various tumour microenvironment (TME) conditions (such as deformed tumour vasculature, various over-expressed receptor proteins, reduced pH, oxidative stress, and resulting elevated glutathione levels) can aid in achieving improved pharmacokinetics, higher tumour accumulation, enhanced antitumour efficacy, and/or decreased side effects and multidrug resistance (MDR) inhibition. Polymeric nanoparticles (PNPs) are being widely investigated in this regard due to their unique features such as small size, passive/active targeting possibility, better pharmaceutical kinetics and biological distribution, decreased adverse reactions of the established drugs, inherent inhibitory properties to MDR efflux pump proteins, as well as the feasibility of delivering numerous therapeutic substances in just one design. Hence in this review, we have primarily discussed PNPs based targeted and/or controlled SDSs in which we have elaborated upon different TME mediated nanotheranostic platforms (NTPs) including active/passive/magnetic targeting platforms along with pH/ROS/redox-responsive platforms. Besides, we have elucidated different imaging guided cancer therapeutic platforms based on four major cancer imaging techniques i.e., fluorescence/photo-acoustic/radionuclide/magnetic resonance imaging, Furthermore, we have deliberated some of the most recently developed PNPs based multimodal NTPs (by combining two or more imaging or therapy techniques on a single nanoplatform) in cancer theranostics. Moreover, we have provided a brief update on PNPs based NTP which are recently developed to overcome MDR for effective cancer treatment. Additionally, we have briefly discussed about the tissue biodistribution/tumour targeting efficiency of these nanoplatforms along with recent preclinical/clinical studies. Finally, we have elaborated on various limitations associated with PNPs based nanoplatforms.

Nanocarrier-based targeting of metabolic pathways for endometrial cancer: Status and future perspectives

Cancer is the second-most lethal global disease, as per health reports, and is responsible for around 70% of deaths in low- and middle-income countries. Endometrial cancer is one of the emerging malignancies and has been predicted as a public health challenge for the future. Insulin resistance, obesity, and diabetes mellitus are the key metabolic factors that promote risks for the development of endometrial cancer. Various signaling pathways and associated genes are involved in the genesis of endometrial cancer, and any mutation or deletion in such related factors leads to the induction of endometrial cancer. The conventional way of drug delivery has been used for ages but is associated with poor management of cancer due to non-targeting of the endometrial cancer cells, low efficacy of the therapy, and toxicity issues as well. In this context, nanocarrier-based therapy for the management of endometrial cancer is an effective alternate choice that overcomes the problems associated with conventional therapy. In this review article, we highlighted the nanocarrier-based targeting of endometrial cancer, with a special focus on targeting various metabolic signaling pathways. Furthermore, the future perspectives of nanocarrier-based targeting of metabolic pathways in endometrial cancer were also underpinned. It is concluded that targeting metabolic signaling pathways in endometrial cancer via nanocarrier scaffolds is the future of pharmaceutical design for the significant management and treatment of endometrial cancer.

Transferrin-Targeted Liposomes in Glioblastoma Therapy: A Review

Glioblastoma (GBM) is a highly aggressive brain tumor, and its treatment is further complicated by the high selectivity of the blood-brain barrier (BBB). The scientific community is urgently seeking innovative and effective therapeutic solutions. Liposomes are a promising new tool that has shown potential in addressing the limitations of chemotherapy, such as poor bioavailability and toxicity to healthy cells. However, passive targeting strategies based solely on the physicochemical properties of liposomes have proven ineffective due to a lack of tissue specificity. Accordingly, the upregulation of transferrin receptors (TfRs) in brain tissue has led to the development of TfR-targeted anticancer therapeutics. Currently, one of the most widely adopted methods for improving drug delivery in the treatment of GBM and other neurological disorders is the utilization of active targeting strategies that specifically target this receptor. In this review, we discuss the role of Tf-conjugated liposomes in GBM therapy and present some recent studies investigating the drug delivery efficiency of Tf-liposomes; in addition, we address some challenges currently facing this approach to treatment and present some potential improvement possibilities.

Delivery of Doxorubicin by Ferric Ion-Modified Mesoporous Polydopamine Nanoparticles and Anticancer Activity against HCT-116 Cells In Vitro

In clinical cancer research, photothermal therapy is one of the most effective ways to increase sensitivity to chemotherapy. Here, we present a simple and effective method for developing a nanotherapeutic agent for chemotherapy combined with photothermal therapy. The nanotherapeutic agent mesoporous polydopamine-Fe(III)-doxorubicin-hyaluronic acid (MPDA-Fe(III)-DOX-HA) was composed of mesoporous polydopamine modified by ferric ions and loaded with the anticancer drug doxorubicin (DOX), as well as an outer layer coating of hyaluronic acid. The pore size of the mesoporous polydopamine was larger than that of the common polydopamine nanoparticles, and the particle size of MPDA-Fe(III)-DOX-HA nanoparticles was 179 ± 19 nm. With the presence of ferric ions, the heat generation effect of the MPDA-Fe(III)-DOX-HA nanoparticles in the near-infrared light at 808 nm was enhanced. In addition, the experimental findings revealed that the active targeting of hyaluronic acid to tumor cells mitigated the toxicity of DOX on normal cells. Furthermore, under 808 nm illumination, the MPDA-Fe(III)-DOX-HA nanoparticles demonstrated potent cytotoxicity to HCT-116 cells, indicating a good anti-tumor effect in vitro. Therefore, the system developed in this work merits further investigation as a potential nanotherapeutic platform for photothermal treatment of cancer.

Implications of biomimetic nanocarriers in targeted drug delivery

Nanomaterials and nanostructures have shown fascinating performances in various biomedicine fields, from cosmetic to cancer diagnosis and therapy. Engineered nanomaterials can encapsulate both lipophilic and hydrophilic substances/drugs to eliminate their limitations in the free forms, such as low bioavailability, multiple drug administration, off-target effects, and various side effects. Moreover, it is possible to deliver the loaded cargo to the desired site of action using engineered nanomaterials. One approach that has made nanocarriers more sophisticated is the "biomimetic" concept. In this scenario, biomolecules (e.g., natural proteins, peptides, phospholipids, cell membranes) are used as building blocks to construct nanocarriers and/or modify agents. For instance, it has been reported that specific cells tend to migrate to a particular site during specific circumstances (e.g., inflammation, tumor formation). Employing the cell membrane of these cells as a coating for nanocarriers confers practical targeting approaches. Accordingly, we introduce the biomimetic concept in the current study, review the recent studies, challenge the issues, and provide practical solutions.

Gastrointestinal Tract Stabilized Protein Delivery Using Disulfide Thermostable Exoshell System

Thermostable exoshells (tES) are engineered proteinaceous nanoparticles used for the rapid encapsulation of therapeutic proteins/enzymes, whereby the nanoplatform protects the payload from proteases and other denaturants. Given the significance of oral delivery as the preferred model for drug administration, we structurally improved the stability of tES through multiple inter-subunit disulfide linkages that were initially absent in the parent molecule. The disulfide-linked tES, as compared to tES, significantly stabilized the activity of encapsulated horseradish peroxidase (HRP) at acidic pH and against the primary human digestive enzymes, pepsin, and trypsin. Furthermore, the disulfide-linked tES (DS-tES) exhibited significant intestinal permeability as evaluated using Caco2 cells. In vivo bioluminescence assay showed that encapsulated Renilla luciferase (rluc) was ~3 times more stable in mice compared to the free enzyme. DS-tES collected mice feces had ~100 times more active enzyme in comparison to the control (free enzyme) after 24 h of oral administration, demonstrating strong intestinal stability. Taken together, the in vitro and in vivo results demonstrate the potential of DS-tES for intraluminal and systemic oral drug delivery applications.

Kill two birds with one stone: Engineered exosome-mediated delivery of cholesterol modified YY1-siRNA enhances chemoradiotherapy sensitivity of glioblastoma

Glioblastoma (GBM) is the most malignant tumor of the central nervous system in adults. Irradiation (IR) and temozolomide (TMZ) play an extremely important role in the treatment of GBM. However, major impediments to effective treatment are postoperative tumor recurrence and acquired resistance to chemoradiotherapy. Our previous studies confirm that Yin Yang 1 (YY1) is highly expressed in GBM, whereby it is associated with cell dedifferentiation, survival, and therapeutic resistance. Targeted delivery of small interfering RNA (siRNA) without blood-brain barrier (BBB) restriction for eradication of GBM represents a promising approach for therapeutic interventions. In this study, we utilize the engineering technology to generate T7 peptide-decorated exosome (T7-exo). T7 is a peptide specifically binding to the transferrin receptor. T7-exo shows excellent packaging and protection of cholesterol-modified Cy3-siYY1 while quickly releasing payloads in a cytoplasmic reductive environment. The engineered exosomes T7-siYY1-exo could deliver more effciently to GBM cells both in vitro and in vivo. Notably, in vitro experiments demonstrate that T7-siYY1-exo can enhance chemoradiotherapy sensitivity and reverse therapeutic resistance. Moreover, T7-siYY1-exo and TMZ/IR exert synergistic anti-GBM effect and significantly improves the survival time of GBM bearing mice. Our findings indicate that T7-siYY1-exo may be a potential approach to reverse the chemoradiotherapy resistance in GBM.

Synthesis and preparation of vitamin A coupled butein-loaded solid lipid nanoparticles for liver fibrosis therapy in rats

The development of a therapeutic system for hepatic fibrosis has become a research hotspot to date. Butein, a simple chalcone derivative, displays anti-fibrotic effects through different pathways. However, impurities, low solubility, and low concentration in the target tissue hinder therapy with herbal ingredients. Hepatic stellate cells (HSCs), the vitamin A (VA) storage cells, as the main contributors to liver fibrogenesis, are not readily accessible to drugs owing to their anatomical location. Targeted delivery of therapeutics to the activated HSCs is therefore critical for successful treatment. For these reasons, the current study aimed at increasing butein delivery to the liver. Hence, high purity butein was synthesized in three steps. A novel VA-Myrj52 ester conjugate was also synthesized using all-trans retinoic acid and a hydrophilic emulsifier (Myrj52) as a targeting agent. Next, butein was encapsulated inside the novel VA-modified solid lipid nanoparticles (VA-SLNs) and studied in vitro and in vivo. According to our evaluations, negatively charged SLNs with a mean diameter of 150 nm and entrapment efficacy of 75 % were successful in liver fibrosis amelioration. Intraperitoneal (i.p.) injection of VA-SLNs in fibrotic rats, for four weeks long, reduced serum AST and ALT by 58% (P, 0.001) and 72% (P, 0.05), respectively, concerning the CCl₄ group. Additionally, histologic damage score decline and normalization of tissue oxidative stress markers collectively confirmed the efficacy of formulations in hepatic fibrosis and kidney damage amelioration.