Targeting efficiency of RGD-modified nanocarriers with different ligand intervals in response to integrin αvβ3 clustering

Characterization of herpetrione amorphous nanoparticles stabilized by hydroxypropylmethyl cellulose and its absorption mechanism in vitro

Herpetrione(HPE) is an effective compound that has been used in the treatment of liver diseases. To improve its dissolution and absorption, herpetrione nanosuspensions was prepared. Nanosuspensions were proved to achieve intact absorption in vivo. However, the transport mechanisms are not fully understood, especially lack of direct evidence of translocation of particulates. In this study, an environment-responsive dye, P4, was loaded into herpetrione amorphous nanoparticles (HPE-ANPs) to elucidate the absorption and transport mechanism of the nanoparticles. And the amount of HPE and nanoparticles in the samples were quantified using HPLC/LC-MS/MS and IVIS with the model of Caco-2 and Caco-2/HT29-MTX. Results demonstrated that HPE is mainly taken up by passive diffusion in the form of free drugs, while HPE-ANPs are internalized by an energy dependent active transport pathway or intracellular endocytosis. It is speculated that HPE-ANPs may change the original entry pathway of drug molecules. Furthermore, the presence of mucus layer and the use of HPMC E15 may contribute to drug absorption to some extent. Transcellular transport study indicates that HPE-ANPs has a poor absorption. In conclusion, the differences in the absorption behavior trends of HPE-ANPs are caused by the difference in particle properties and the form of existence of the drug.

Rational Design, Multistep Synthesis and in Vitro Evaluation of Poly(glycerol) Functionalized Nanodiamond Conjugated with Boron-10 Cluster and Active Targeting Moiety for Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT), advanced cancer treatment utilizing nuclear fission of 10 B atom in cancer cells, is attracting increasing attention. As 10 B delivery agent, sodium borocaptate (10 BSH, 10 B12 H11 SH ⋅ 2Na), has been used in clinical studies along with L-boronophenylalanine. Recently, this boron cluster has been conjugated with lipids, polymers or nanoparticles to increase selectivity to and retentivity in tumor. In this work, anticancer nanoformulations for BNCT are designed, consisting of poly(glycerol) functionalized detonation nanodiamonds (DND-PG) as a hydrophilic nanocarrier, the boron cluster moiety (10 B12 H11 2- ) as a dense boron-10 source, and phenylboronic acid or RGD peptide as an active targeting moiety. Some hydroxy groups in PG were oxidized to carboxy groups (DND-PG-COOH) to conjugate the active targeting moiety. Some hydroxy groups in DND-PG-COOH were then transformed to azide to conjugate 10 B12 H11 2- through click chemistry. The nanodrugs were evaluated in vitro using B16 murine melanoma cells in terms of cell viability, BNCT efficacy and cellular uptake. As a result, the 10 B12 H11 2- moiety is found to facilitate cellular uptake probably due to its negative charge. Upon thermal neutron irradiation, the nanodrugs with 10 B12 H11 2- moiety exhibited good anticancer efficacies with slight differences with and without targeting moiety.

Integration of an LPAR1 Antagonist into Liposomes Enhances Their Internalization and Tumor Accumulation in an Animal Model of Human Metastatic Breast Cancer

Lysophosphatidic acid receptor 1 (LPAR1) is elevated in breast cancer. The deregulation of LPAR1, including the function and level of expression, is linked to cancer initiation, progression, and metastasis. LPAR1 antagonists, AM095 or Ki16425, may be effective therapeutic molecules, yet their limited water solubility hinders in vivo delivery. In this study, we report on the synthesis of two liposomal formulations incorporating AM095 or Ki16425, embedded within the lipid bilayer, as targeted nanocarriers for metastatic breast cancer (MBC). The data show that the Ki16425 liposomal formulation exhibited a 50% increase in internalization by MBC mouse epithelial cells (4T1) and a 100% increase in tumor accumulation in a mouse model of MBC compared with that of a blank liposomal formulation (control). At the same time, normal mouse epithelial cells (EpH-4Ev) internalized the Ki16425 liposomal formulation 25% lesser than the control formulation. Molecular dynamics simulations show that the integration of AM095 or Ki16425 modified the physical and mechanical properties of the lipid bilayer, making it more flexible in these liposomal formulations compared with liposomes without drug. The incorporation of an LPAR1 antagonist within a liposomal drug delivery system represents a viable therapeutic approach for targeting the LPA-LPAR1 axis, which may hinder the progression of MBC.

Surface modification strategies in translocating nano-vesicles across different barriers and the role of bio-vesicles in improving anticancer therapy

Nanovesicles and bio-vesicles (BVs) have emerged as promising tools to achieve targeted cancer therapy due to their ability to overcome many of the key challenges currently being faced with conventional chemotherapy. These challenges include the diverse and often complex pathophysiology involving the progression of cancer, as well as the various biological barriers that circumvent therapeutic molecules reaching their target site in optimum concentration. The scientific evidence suggests that surface-functionalized nanovesicles and BVs camouflaged nano-carriers (NCs) both can bypass the established biological barriers and facilitate fourth-generation targeting for the improved regimen of treatment. In this review, we intend to emphasize the role of surface-functionalized nanovesicles and BVs camouflaged NCs through various approaches that lead to an improved internalization to achieve improved and targeted oncotherapy. We have explored various strategies that have been employed to surface-functionalize and biologically modify these vesicles, including the use of biomolecule functionalized target ligands such as peptides, antibodies, and aptamers, as well as the targeting of specific receptors on cancer cells. Further, the utility of BVs, which are made from the membranes of cells such as mesenchymal stem cells (MSCs), white blood cells (WBCs), red blood cells (RBCs), platelets (PLTs) as well as cancer cells also been investigated. Lastly, we have discussed the translational challenges and limitations that these NCs can encounter and still need to be overcome in order to fully realize the potential of nanovesicles and BVs for targeted cancer therapy. The fundamental challenges that currently prevent successful cancer therapy and the necessity of novel delivery systems are in the offing.

Lipid polymer hybrid nanoparticles: a custom-tailored next-generation approach for cancer therapeutics

Lipid-based polymeric nanoparticles are the highly popular carrier systems for cancer drug therapy. But presently, detailed investigations have revealed their flaws as drug delivery carriers. Lipid polymer hybrid nanoparticles (LPHNPs) are advanced core-shell nanoconstructs with a polymeric core region enclosed by a lipidic layer, presumed to be derived from both liposomes and polymeric nanounits. This unique concept is of utmost importance as a combinable drug delivery platform in oncology due to its dual structured character. To add advantage and restrict one's limitation by other, LPHNPs have been designed so to gain number of advantages such as stability, high loading of cargo, increased biocompatibility, rate-limiting controlled release, and elevated drug half-lives as well as therapeutic effectiveness while minimizing their drawbacks. The outer shell, in particular, can be functionalized in a variety of ways with stimuli-responsive moieties and ligands to provide intelligent holding and for active targeting of antineoplastic medicines, transport of genes, and theragnostic. This review comprehensively provides insight into recent substantial advancements in developing strategies for treating various cancer using LPHNPs. The bioactivity assessment factors have also been highlighted with a discussion of LPHNPs future clinical prospects.

A peptidic network antibody inhibits both angiogenesis and inflammatory response

Corneal neovascularization (CNV) is a global threat to human health. Traditional anti-angiogenesis agent may have therapy effect, while the inflammation in disease area remains unsolved. Herein, we reported two binding-induced fibrillogenesis (BIF) peptides as peptidic network antibodies for high-efficient and long-lasting anti-angiogenesis with reduced inflammatory response. BIF peptides could self-assemble into nanoparticles and further perform BIF behavior through binding Ca2+. In vitro, the migration of integrin αvβ3 highly expressed endothelial cells was inhibited by BIF peptides. In vivo, one BIF peptide (0.012 mg/Kg) exhibited higher anti-angiogenesis effect than monoclonal antibody bevacizumab (0.96 mg/Kg) in a CNV rabbit model on day 14, despite that the dose of BIF was only 1.3% of bevacizumab. Meanwhile, the inflammatory response, such as PI3 kinase/Akt pathway in CNV was successfully inhibited as well. The peptidic network antibody could block integrin αvβ3 via a long-term retention mode, which led to long-term therapeutic effect. The study provides BIF peptides as promising therapeutic agents for both anti-angiogenesis and reduced inflammatory response.

Targeted nanodelivery of siRNA against KRAS G12D inhibits pancreatic cancer

Pancreatic cancer (PC) stands as a most deadly malignancy due to few effective treatments in the clinics. KRAS G12D mutation is a major driver for most PC cases, and silencing of KRAS G12D is considered as a potential therapeutic strategy for PC, which is nevertheless crippled by lacking a pragmatic delivery system for siRNA against KRAS G12D (siKRAS). Here, we report that cRGD peptide-modified bioresponsive chimaeric polymersomes (cRGD-BCP) mediate highly efficient siKRAS delivery to PANC-1 tumor, potently silencing KRAS G12D mRNA in tumor cells and effectively suppressing PC tumor growth in mice. cRGD-BCP exhibited remarkable encapsulation of siKRAS (loading content > 14 wt.%, loading efficiency > 90%) to form stable and uniform (ca. 68 nm) nanovesicles (cRGD-BCP-siKRAS). Of note, cRGD density greatly impacted the cellular uptake and silencing efficiency of cRGD-BCP-siKRAS in PANC-1 cells, in which an optimal cRGD density of 15.7 mol.% achieved 3.7- and 3.6-fold enhancement of internalization and gene silencing, respectively, compared with non-targeted BCP-siKRAS. cRGD-BCP-siKRAS was practically intact after 3-week storage at 4°C. Intriguingly, cRGD-BCP-siKRAS markedly enhanced the uptake of siKRAS in PANC-1 tumor, and at a siKRAS dose of 3 mg/kg knocked down 90% KRAS G12D gene, resulting in potent tumor inhibition and extraordinary survival benefits (median survival time: 101 days versus 38 (PBS group) and 59 days (BCP-siKRAS)) with 40% mice achieved complete regression. It appears that cRGD-mediated nanodelivery of siKRAS provides a potential cure for pancreatic cancer. STATEMENT OF SIGNIFICANCE: Small interfering RNA (siRNA) emerges as a specific and powerful biopharmaceuticals against cancers; however, inefficient in vivo delivery impedes its clinical translation. In spite of the fact that KRAS G12D mutation has been identified as a major driver for most pancreatic cancer, its notorious non-druggability renders little success on development of molecular targeted drugs. Pancreatic cancer is deemed as current king-of-cancer. Here, we show that cyclic RGD peptide installed bioresponsive polymersomes are able to efficiently deliver siRNA against KRAS G12D to pancreatic tumor, resulting in 90% gene knock-down and effective tumor inhibition. Strikingly, two out of five mice have been cured. This targeted nanodelivery of siRNA provides a high-efficacy treatment strategy for pancreatic cancer.

Advanced liposome and polymersome-based drug delivery systems: Considerations for physicochemical properties, targeting strategies and stimuli-sensitive approaches

Liposomes and polymersomes are colloidal vesicles that are self-assembled from lipids and amphiphilic polymers, respectively. Because of their ability to encapsulate both hydrophilic and hydrophobic therapeutics, they are of great interest in drug delivery research. Today, the applications of liposomes and polymersomes have expanded to a wide variety of complex therapeutic molecules, including nucleic acids, proteins and enzymes. Thanks to their chemical versatility, they can be tailored to different drug delivery applications to achieve maximum therapeutic index. This review article evaluates liposomes and polymersomes from a perspective that takes into account the physical and biological barriers that reduce the efficiency of the drug delivery process. In this context, the design approaches of liposomes and polymersomes are discussed with representative examples in terms of their physicochemical properties (size, shape, charge, mechanical), targeting strategies (passive and active) and response to different stimuli (pH, redox, enzyme, temperature, light, magnetic field, ultrasound). Finally, the challenges limiting the transition from laboratory to practice, recent clinical developments, and future perspectives are addressed.

Quantitative Ratiometric Biosensors Based on Fluorescent Ferrocene-Modified Histidine Dipeptide Nanoassemblies

Fluorescent proteins (FPs) provide a ratiometric readout for quantitative assessment of the destination of internalized biomolecules. FP-inspired peptide nanostructures that can compete with FPs in their capacity are the most preferred building blocks for the synthesis of fluorescent soft matter. However, realizing a ratiometric emission from a single peptide fluorophore remains exclusive since multicolor emission is a rare property in peptide nanostructures. Here, we describe a bioinspired peptidyl platform for ratiometric intracellular quantitation by employing a single ferrocene-modified histidine dipeptide. The intensiometric ratio of green to blue fluorescence correlates linearly with the concentration of the peptide by three orders of magnitude. The ratiometric fluorescence of the peptide is an assembly-induced emission originating from hydrogen bonds and aromatic interactions. Additionally, modular design enables ferrocene-modified histidine dipeptides to use as a general platform for the construction of intricate peptides that retain the ratiometric fluorescent properties. The ratiometric peptide technique promises flexibility in the design of a wide spectrum of stoichiometric biosensors for quantitatively understanding the trafficking and subcellular fate of biomolecules.

Polymer- and lipid-based nanocarriers for ocular drug delivery: Current status and future perspectives

Ocular diseases seriously affect patients' vision and life quality, with a global morbidity of over 43 million blindness. However, efficient drug delivery to treat ocular diseases, particularly intraocular disorders, remains a huge challenge due to multiple ocular barriers that significantly affect the ultimate therapeutic efficacy of drugs. Recent advances in nanocarrier technology offer a promising opportunity to overcome these barriers by providing enhanced penetration, increased retention, improved solubility, reduced toxicity, prolonged release, and targeted delivery of the loaded drug to the eyes. This review primarily provides an overview of the progress and contemporary applications of nanocarriers, mainly polymer- and lipid-based nanocarriers, in treating various eye diseases, highlighting their value in achieving efficient ocular drug delivery. Additionally, the review covers the ocular barriers and administration routes, as well as the prospective future developments and challenges in the field of nanocarriers for treating ocular diseases.

A glutathione-sensitive cationic polymer delivery of CRISPR-Cas9 RNA plasmid for targeting nasopharyngeal carcinoma gene therapy

CRISPR-Cas9 technology has been proven to be the most straightforward and accurate tool for gene therapy, but some limitations, such as the inefficient transfection or inability to precisely target, prevent the gene therapy from achieving the desired therapeutic effect. To overcome these, a kind of glutathione-sensitive cationic vectors, hyperbranched polyamide amine (HPAA) was designed for Delivery of CRISPR-Cas9 RNA plasmid, and the cyclic RGD (Arg-Gly-Asp) was conjugated for the targeted treatment of nasopharyngeal carcinoma (NPC). Disulfide bonds in HPAA segments can specifically respond to the high glutathione concentration in the tumor microenvironment. Meanwhile, RGD could especially interact to the integrin α_vβ₃ receptors which are highly expressed on the surface of NPC tumor cells. The results showed that more HPAA-RGD/SGK3-gRNA complexes could be uptaken by NPC HNE-1 cells after RGD was conjugated, and then the plasmid could be accumulated in the NPC tumor as well, which may assure the satisfied NPC therapy effect in vivo. In transfection assays, this complex showed the acceptable gene transfection efficiency in vitro and the obvious tumor inhibition effect in vivo, suggested a potential application in gene therapy to NPC.

Observation of the protein expression level via naked eye: Pt clusters catalyze non-color molecules into brown-colored molecules in cells

α _v β ₃ is overexpressed in various tumor cells and plays a key role in tumor genesis, invasion, and metastasis. Therefore, it is of great significance to precisely detect the α _v β ₃ level in cells via a simple method. For this purpose, we have constructed a peptide-coated platinum (Pt) cluster. Due to its bright fluorescence, well-defined Pt atom numbers, and peroxidase-like catalytic activity, this cluster can be used to evaluate α _v β ₃ levels in cells by fluorescence imaging, inductively coupled plasma mass spectrometry (ICP-MS), and catalytic amplification of visual dyes, respectively. In this report, the expression level of α _v β ₃ in living cells is well-detected by the naked eye under an ordinary light microscope when the Pt cluster binds to αvβ3 in cells and catalyzes non-color 3,3'-diaminobenzidine (DAB) into brown-colored molecules in situ. Moreover, SiHa, HeLa, and 16HBE cell lines with different α _v β ₃ expression levels can be visually distinguished by the peroxidase-like Pt clusters. This research will provide a reliable method for the simple detection of α _v β ₃ levels in cells.

In-situ forming injectable GFOGER-conjugated BMSCs-laden hydrogels for osteochondral regeneration

The collagen-mimetic peptide GFOGER possesses the chondrogenic potential and has been used as a cell adhesion peptide or chondrogenic inducer. Here, we prepared an injectable in situ forming composite hydrogel system comprising methoxy polyethylene glycol-b-polycaprolactone (MPEG-PCL) and GFOGER-conjugated PEG-PCL (GFOGER-PEG-PCL) with various GFOGER concentrations based on our recently patented technology. The conjugation of GFOGER to PEG-PCL was confirmed by ¹H NMR, and the particle size distribution and rheological properties for the sol-gel transition behavior of the samples with respect to the GFOGER content were evaluated systemically. In vitro experiments using rat bone marrow-derived mesenchymal stem cells (BMSCs) revealed that the GFOGER-PEG-PCL hydrogel significantly enhanced expression of integrins (β1, α2, and α11), increased expression of FAK, and induced downstream signaling of ERK and p38. Overexpression of chondrogenic markers suggested that BMSCs have the potential to differentiate into chondrogenic lineages within GFOGER-PEG-PCL samples. In vivo studies using a rat osteochondral defect model revealed that transplanted BMSCs with GFOGER_0.8-PEG-PCL survived at the defect with strong chondrogenic expression after 4 weeks. The stem cell-laden GFOGER_0.8-PEG-PCL hydrogel produced remarkable osteochondral regeneration at 8 weeks of transplantation, as determined by histological findings and micro-CT analysis. The histomorphological score in the GFOGER_0.8-PEG-PCL + BMSCs group was ~1.7-, 2.6-, and 5.3-fold higher than that in the GFOGER_0.8-PEG-PCL, MPEG-PCL, and defect groups, respectively. Taken together, these results provide an important platform for further advanced GFOGER-based stem cell research for osteochondral repair.

Synthesis and evaluation of a novel adapter lipid derivative for preparation of cyclic peptide-modified PEGylated liposomes: Application of cyclic RGD peptide

Peptide ligand modified nanoparticles can simply prepared by post-insertion method to mix pre-formed nanoparticles with peptide-lipid conjugates in an aqueous solution at an optimal temperature. Therefore, water dispersibility of peptide-lipid conjugates is a very important factor for implementing the post-insertion method. We proposed that highly water dispersible peptide-lipid conjugates can be easily synthesized by separately designing novel adapter lipids with different water dispersibility and reacting them with ligands in a highly efficient manner. Adapter lipids have three critical roles; as spacers of ligand-conjugated lipids for efficient ligand presentation, as structures that form discrete molecular weight distributions, and as providing water dispersibility. In this study, we developed a novel adapter-lipid derivative that enables a variety of cyclic peptide modifications using the click reaction. The integrin αvβ₃-targeted cyclic RGDfK (cRGD) peptide was selected as the cyclic peptide ligand. We designed a novel alkyne-tagged lipid with a discrete peptide spacer and bound the cRGD peptide using a click reaction to synthesize a cRGD-conjugated lipid with good water dispersibility for the preparation of cRGD-modified PEGylated liposomes using the post-insertion method. We also revealed that cRGD-modified PEGylated liposomes are efficiently associated with integrin αvβ3-expressing murine colon carcinoma (Colon-26) cells in a modification amount- and peptide sequence-dependent manner, showing high cytotoxicity upon loading with doxorubicin. This novel adapter lipid derivative can be used to synthesize various cyclic peptides by click reactions and will provide useful insights for the future development of cyclic peptide-modified PEGylated liposomes.

Near-Infrared-Enpowered Nanomotor-Mediated Targeted Chemotherapy and Mitochondrial Phototherapy to Boost Systematic Antitumor Immunity

Phototherapy is an important strategy to inhibit tumor growth and activate antitumor immunity. However, the effect of photothermal/photodynamic therapy (PTT/PDT) is restricted by limited tumor penetration depth and unsatisfactory potentiation of antitumor immunity. Here, a near-infrared (NIR)-driven nanomotor is constructed with a mesoporous silicon nanoparticle (MSN) as the core, end-capped with Antheraea pernyi silk fibroin (ApSF) comprising arginine-glycine-aspartate (RGD) tripeptides. Upon NIR irradiation, the resulting ApSF-coated MSNs (DIMs) loading with photosensitizers (ICG derivatives, IDs) and chemotherapeutic drugs (doxorubicin, Dox) can efficiently penetrate into the internal tumor tissues and achieve effective phototherapy. Combined with chemotherapy, a triple-modal treatment (PTT, PDT, and chemotherapy) approach is developed to induce the immunogenic cell death of tumor cells and to accelerate the release of damage-associated molecular patterns. In vivo results suggest that DIMs can promote the maturation of dendritic cells and surge the number of infiltrated immune cells. Meanwhile, DIMs can polarize macrophages from M2 to M1 phenotypes and reduce the percentages of immunosuppressive Tregs, which reverse the immunosuppressive tumor microenvironment and activate systemic antitumor immunity. By achieving synergistic effects on the tumor inhibition and the antitumor immunity activation, DIMs show great promise as new nanoplatforms to treat metastatic breast cancer.

Triple branched RGD modification on liposomes: A prospective strategy to enhance the glioma targeting efficiency

Glioma, as one of the most common primary intracranial tumors, is in an urgent need for specific targeting agents. Multi-branched RGD ligand is a promising alternative for liposome functionalization which combines the benefits of high affinity with α_vβ₃ receptors and proper branching structure in response to the receptor clustering. Herein, we designed and synthesized single branched, double branched and triple branched RGD ligand (1RGD-Chol, 2RGD-Chol and 3RGD-Chol) respectively, which were then modified on the liposomes to prepare six different kinds of liposomes (including 1RGD-Lip, 2RGD-Lip, 3RGD-Lip, 2 × 1RGD-Lip, 3 × 1RGD-Lip and unmodified Lip). Subsequently, a series of assays were conducted. The results exhibited that the liposome decorated with 3RGD-Chol ligand possessed superior cellular internalization ability in C6 cells and bEnd.3 cells, suggesting the strongest ability of 3RGD-Lip to target the blood-brain barrier (BBB) and glioma cells. Besides, both the cytotoxicity and pro-apoptotic assays revealed that PTX-3RGD-Lip had the strongest ability to inhibit the survival of C6 cells. Moreover, the enrichment of liposomes at tumor site was 3RGD-Lip > 3 × 1RGD-Lip ≈ 2RGD-Lip ≈ 2 × 1RGD-Lip > 1RGD-Lip > Lip according to the in vivo imaging of C6-bearing mice, which was consistent with the result of in vitro targeting experiments. To sum up, the targeting efficiency of liposomes can be strongly promoted by improving the amount of targeting molecules, whereas the branching structure and spatial distance of RGD residues also accounted for the affinity between liposomes and α_vβ₃ receptors. Collectively, PTX-3RGD-Lip would be a prospective strategy in glioma treatment.

Recent Progress of RGD Modified Liposomes as Multistage Rocket Against Cancer

Cancer is a life-threatening disease, contributing approximately 9.4 million deaths worldwide. To address this challenge, scientific researchers have investigated molecules that could act as speed-breakers for cancer. As an abiotic drug delivery system, liposomes can hold both hydrophilic and lipophilic drugs, which promote a controlled release, accumulate in the tumor microenvironment, and achieve elongated half-life with an enhanced safety profile. To further improve the safety and impair the off-target effect, the surface of liposomes could be modified in a way that is easily identified by cancer cells, promotes uptake, and facilitates angiogenesis. Integrins are overexpressed on cancer cells, which upon activation promote downstream cell signaling and eventually activate specific pathways, promoting cell growth, proliferation, and migration. RGD peptides are easily recognized by integrin over expressed cells. Just like a multistage rocket, ligand anchored liposomes can be selectively recognized by target cells, accumulate at the specific site, and finally, release the drug in a specific and desired way. This review highlights the role of integrin in cancer development, so gain more insights into the phenomenon of tumor initiation and survival. Since RGD is recognized by the integrin family, the fate of RGD has been demonstrated after its binding with the acceptor’s family. The role of RGD based liposomes in targeting various cancer cells is also highlighted in the paper.

Current understandings and clinical translation of nanomedicines for breast cancer therapy

Breast cancer is one of the most frequently diagnosed cancers that is threatening women's life. Current clinical treatment regimens for breast cancer often involve neoadjuvant and adjuvant systemic therapies, which somewhat are associated with unfavorable features. Also, the heterogeneous nature of breast cancers requires precision medicine that cannot be fulfilled by a single type of systemically administered drug. Taking advantage of the nanocarriers, nanomedicines emerge as promising therapeutic agents for breast cancer that could resolve the defects of drugs and achieve precise drug delivery to almost all sites of primary and metastatic breast tumors (e.g. tumor vasculature, tumor stroma components, breast cancer cells, and some immune cells). Seven nanomedicines as represented by Doxil® have been approved for breast cancer clinical treatment so far. More nanomedicines including both non-targeting and active targeting nanomedicines are being evaluated in the clinical trials. However, we have to realize that the translation of nanomedicines, particularly the active targeting nanomedicines is not as successful as people have expected. This review provides a comprehensive landscape of the nanomedicines for breast cancer treatment, from laboratory investigations to clinical applications. We also highlight the key advances in the understanding of the biological fate and the targeting strategies of breast cancer nanomedicine and the implications to clinical translation.

Theranostic near-infrared-IIb emitting nanoprobes for promoting immunogenic radiotherapy and abscopal effects against cancer metastasis

Radiotherapy is an important therapeutic strategy for cancer treatment through direct damage to cancer cells and augmentation of antitumor immune responses. However, the efficacy of radiotherapy is limited by hypoxia-mediated radioresistance and immunosuppression in tumor microenvironment. Here, we construct a stabilized theranostic nanoprobe based on quantum dots emitting in the near-infrared IIb (NIR-IIb, 1,500-1,700 nm) window modified by catalase, arginine-glycine-aspartate peptides and poly(ethylene glycol). We demonstrate that the nanoprobes effectively aggregate in the tumor site to locate the tumor region, thereby realizing precision radiotherapy with few side-effects. In addition, nanoprobes relieve intratumoral hypoxia and reduce the tumor infiltration of immunosuppressive cells. Moreover, the nanoprobes promote the immunogenic cell death of cancer cells to trigger the activation of dendritic cells and enhance T cell-mediated antitumor immunity to inhibit tumor metastasis. Collectively, the nanoprobe-mediated immunogenic radiotherapy can boost the abscopal effect to inhibit tumor metastasis and prolong survival.

A Monotargeting Peptidic Network Antibody Inhibits More Receptors for Anti-Angiogenesis

The overexpression of growth factors and receptors on neovascular endothelial cells (ECs) and their binding may promote the abnormal growth of new blood vessels, leading to corneal neovascularization (CNV). Normally, monoclonal antibodies may bind and block only one growth factor or receptor, such as bevacizumab binding and blocking vascular endothelial growth factor (VEGF). Herein, we develop a monotargeting peptidic network antibody (pepnetibody) that blocks multiple receptors on the membrane of ECs through forming a fibrous network and ultimately achieves high-efficient treatment of CNV. The pepnetibody could bind to integrin α_vβ₃ in particulate formulation and in situ fibrillogenesis on ECs, mimicking the process of fibronectin fibrillogenesis on the cell membrane. The in situ formed peptidic network could firmly block integrin and cover other angiogenesis-related receptors, such as VEGF receptor-2 and neuropilin-1, exhibiting competitive efficacy of antiangiogenesis compared with traditional monoclonal antibody bevacizumab with 97.7 times lower dose.

Recent Applications of Retro-Inverso Peptides

Natural and de novo designed peptides are gaining an ever-growing interest as drugs against several diseases. Their use is however limited by the intrinsic low bioavailability and poor stability. To overcome these issues retro-inverso analogues have been investigated for decades as more stable surrogates of peptides composed of natural amino acids. Retro-inverso peptides possess reversed sequences and chirality compared to the parent molecules maintaining at the same time an identical array of side chains and in some cases similar structure. The inverted chirality renders them less prone to degradation by endogenous proteases conferring enhanced half-lives and an increased potential as new drugs. However, given their general incapability to adopt the 3D structure of the parent peptides their application should be careful evaluated and investigated case by case. Here, we review the application of retro-inverso peptides in anticancer therapies, in immunology, in neurodegenerative diseases, and as antimicrobials, analyzing pros and cons of this interesting subclass of molecules.

Smart Manganese Dioxide-Based Lanthanide Nanoprobes for Triple-Negative Breast Cancer Precise Gene Synergistic Chemodynamic Therapy

Small interfering RNA (siRNA)-based gene therapy has been widely studied as a promising treatment for malignant triple-negative breast cancer (TNBC), but efficient delivery of siRNA still remains a challenge. In this study, a smart manganese dioxide (MnO2)-based lanthanide nanoprobe therapeutic nanoplatform (ErNPs@MnO2-siS100A4-RGD) was developed for tumor imaging and precise stimuli-responsive S100A4 siRNA (siS100A4)-mediated gene therapy in synergism with chemodynamic therapy (CDT) of TNBC. ErNPs@MnO2-siS100A4-RGD has a tumor microenvironment-responsive capability attributed to the presence of MnO2, which can be degraded by glutathione (GSH) in the tumor region while releasing siRNA and generating Mn2+ to achieve precise gene therapy and a Fenton-like reaction-mediated CDT effect on TNBC. Subsequently, the lanthanide nanoprobes (ErNPs) are exposed to the second near-infrared region (NIR-II) fluorescence emission to realize the precise tumor location. Both the in vitro and in vivo results demonstrated that the smart nanoplatform possessed high siRNA delivery efficiency and GSH-responsive precise siRNA releasing ability, and compared with individual gene therapy, the GSH-depletion-enhanced CDT effect further reinforced TNBC inhibition, demonstrating excellent GSH-responsive-enhanced NIR-II precise tumor imaging therapy. These results indicate that the nanoplatform provides a crucial foundation for further research on theranostic systems of TNBC.

Multiple bioanalytical methods reveal a thyroid-disrupting mechanism related to the membrane receptor integrin αvβ3

Di(2-ethylhexyl) phthalate (DEHP), a manufactured chemical, is suitable for large-scale production and has extensive applications. Although restricted for use, DEHP is still ubiquitous in the environment and shows potential to disrupt the structure or function of the thyroid system. However, its toxic mechanism is complex and not clearly understood. In this study, a battery of methods was employed to investigate DEHP-induced thyroid-disrupting effects and their mechanism of action, focusing on a newly discovered membrane receptor-mediated mechanism. The results showed that DEHP promoted rat pituitary tumor (GH3) cell proliferation and c-fos gene expression at environment level concentrations (2 and 5 μmol/L) in a manner similar to that of the natural thyroid hormone 3,3',5-triiodo-L-thyronine (T3). The macromolecule DEHP-BSA cannot pass through the cell membrane to interact with nuclear receptors but upregulated the c-fos gene expression when administered at concentrations comparable to DEHP concentrations; molecular docking demonstrated that DEHP has affinity for the membrane receptor integrin α_vβ₃; DEHP at 2 μmol/L upregulated the β₃ gene expression in GH3 cells; after the addition of integrin α_vβ₃-inhibiting RGD peptide, DEHP-induced c-fos gene upregulation decreased. All of these findings support the supposition that DEHP-induced thyroid-disrupting effects might be mediated by the membrane receptor integrin α_vβ₃. Moreover, DEHP activated the downstream extracellular regulated protein kinase (ERK1/2) pathway, upregulating the gene expression of raf-1, MEK-1 and MAPK1 and increasing the protein levels of p-ERK; interestingly, ERK1/2 activation and c-fos upregulation induced by DEHP were attenuated by PD98059 (an ERK1/2 inhibitor). Taken together, the data suggest that the membrane receptor integrin α_vβ₃ and the downstream ERK1/2 pathway might be involved in DEHP-induced thyroid-disrupting effects. This study provides new insight into the thyroid-disrupting effect and the underlying mechanism and will advance the effort to construct adverse outcome pathways of DEHP and other thyroid hormone disrupting chemicals.

A Dual pH-Responsive DOX-Encapsulated Liposome Combined with Glucose Administration Enhanced Therapeutic Efficacy of Chemotherapy for Cancer

BACKGROUND

The acidic microenvironment of cancer can promote tumor metastasis and drug resistance. Acidic tumor microenvironment-targeted therapy is currently an important means for treating tumors, inhibiting metastasis, and overcoming drug resistance. In this study, a dual pH-responsive DOX-encapsulated liposome (DOPE-DVar7-lip@DOX) was designed and fabricated for targeting the acidic tumor microenvironment. On the one hand, the response of acid-sensitive peptide (DVar7) to the acidic tumor microenvironment increased the uptake of liposomes in tumors and prolonged the retention time; on the other hand, the response of acid-sensitive phospholipid (DOPE) to the acidic tumor microenvironment improved the controlled release of DOX in tumors.

METHODS

The acid-sensitive peptide DVar7 modified liposomes can be obtained by simple incubation of DSPE-DVar7 with DOX-loaded DOPE liposomes (DOPE-lip@DOX). The tumor targeting of the dual pH-responsive liposome was investigated in vitro and in vivo by near-infrared fluorescence imaging. The tumor therapeutic efficacy of DOPE-DVar7-lip@DOX was evaluated in breast cancer mouse model using the traditional liposome as a control. Moreover, we regulated the tumor microenvironment acidity by injecting glucose to further enhance the therapeutic efficacy of cancer.

RESULTS

DVar7 can allosterically insert into the tumor cell membrane in the acidic tumor microenvironment to enhance the tumor uptake of liposomes and prolong the retention time of liposomes in tumor. In addition, the therapeutic efficacy of pH-responsive liposomes can be further enhanced by glucose injection regulating the acidity of tumor microenvironment.

DISCUSSION

DVar7 modified acid-sensitive nanocarriers combined with acidity regulation have great potential to improve drug resistance in clinical practice, thus improving the response rate and therapeutic effect of chemotherapy.

Polydopamine-Coated Laponite Nanoplatforms for Photoacoustic Imaging-Guided Chemo-Phototherapy of Breast Cancer

Theranostic nanoplatforms combining photosensitizers and anticancer drugs have aroused wide interest due to the real-time photoacoustic (PA) imaging capability and improved therapeutic efficacy by the synergistic effect of chemotherapy and phototherapy. In this study, polydopamine (PDA) coated laponite (LAP) nanoplatforms were synthesized to efficiently load indocyanine green (ICG) and doxorubicin (DOX), and modified with polyethylene glycol-arginine-glycine-aspartic acid (PEG-RGD) for PA imaging-guided chemo-phototherapy of cancer cells overexpressing α_vβ₃ integrin. The formed ICG/LAP-PDA-PEG-RGD/DOX nanoplatforms showed significantly higher photothermal conversion efficiency than ICG solution and excellent PA imaging capability, and could release DOX in a pH-sensitive and NIR laser-triggered way, which is highly desirable feature in precision chemotherapy. In addition, the ICG/LAP-PDA-PEG-RGD/DOX nanoplatforms could be uptake by cancer cells overexpressing α_vβ₃ integrin with high specificity, and thus serve as a targeted contrast agent for in vivo PA imaging of cancer. In vivo experiments with 4T1 tumor-bearing mouse model demonstrated that ICG/LAP-PDA-PEG-RGD/DOX nanoplatforms exhibited much stronger therapeutic effect and higher survival rate than monotherapy due to the synergetic chemo-phototherapy under NIR laser irradiation. Therefore, the reported ICG/LAP-PDA-PEG-RGD/DOX represents a promising theranostic nanoplatform for high effectiveness PA imaging-guided chemo-phototherapy of cancer cells overexpressing α_vβ₃ integrin.

Surface Plasmon Resonance as a Characterization Tool for Lipid Nanoparticles Used in Drug Delivery

The development of drug carriers based in lipid nanoparticles (LNPs) aims toward the synthesis of non-toxic multifunctional nanovehicles that can bypass the immune system and allow specific site targeting, controlled release and complete degradation of the carrier components. Among label free techniques, Surface Plasmon Resonance (SPR) biosensing is a versatile tool to study LNPs in the field of nanotherapeutics research. SPR, widely used for the analysis of molecular interactions, is based on the immobilization of one of the interacting partners to the sensor surface, which can be easily achieved in the case of LNPs by hydrophobic attachment onto commercial lipid- capture sensor chips. In the last years SPR technology has emerged as an interesting strategy for studying molecular aspects of drug delivery that determines the efficacy of the nanotherapeutical such as LNPs' interactions with biological targets, with serum proteins and with tumor extracelullar matrix. Moreover, SPR has contributed to the obtention and characterization of LNPs, gathering information about the interplay between components of the formulations, their response to organic molecules and, more recently, the quantification and molecular characterization of exosomes. By the combination of available sensor platforms, assay quickness and straight forward platform adaptation for new carrier systems, SPR is becoming a high throughput technique for LNPs' characterization and analysis.

PAMAM G4.5 dendrimers for targeted delivery of ferulic acid and paclitaxel to overcome P-glycoprotein-mediated multidrug resistance

In this study, we prepared ferulic acid (FA) and paclitaxel (PTX) co-loaded polyamidoamine (PAMAM) dendrimers conjugated with arginyl-glycyl-aspartic acid (RGD) to overcome P-glycoprotein (P-gp)-mediated multidrug resistance (MDR). FA was released in greater extent (80%) from the outer layer of the dendrimers compared with PTX (70%) from the interior of the dendrimers. FA improved intracellular availability of PTX via P-gp modulation in drug-resistant cells. In vitro drug uptake data show higher PTX delivery with RGD-PAMAM-FP than with PAMAM-FP in drug resistant KB CH-R 8-5 cell lines. This indicates that RGD facilitates intracellular PTX accumulation through active targeting in multidrug-resistant KB CH-R 8-5 cells. The terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick-end labeling assay data and membrane potential analysis in mitochondria confirm the enhanced anticancer potential of RGD-PAMAM-FP nanoaggregates in drug-resistant cells. We also confirmed by the increased protein levels of proapoptotic factors such as caspase 3, caspase 9, p53, and Bax after treatment with RGD-PAMAM-FP nanoaggregates and also downregulates antiapoptotic factors. Hence, FA-PTX co-loaded, RGD-functionalized PAMAM G4.5 dendrimers may be considered as an effective therapeutic strategy to induce apoptosis in P-gp-overexpressing, multidrug-resistant cells.

Dual-targeting nanovesicles enhance specificity to dynamic tumor cells in vitro and in vivo via manipulation of αvβ3-ligand binding

The dynamic or flowing tumor cells just as leukemia cells and circulating tumor cells face a microenvironment difference from the solid tumors, and the related targeting nanomedicines are rarely reported. The existence of fluidic shear stress in blood circulation seems not favorable for the binding of ligand modified nanodrugs with their target receptor. Namely, the binding feature is very essential in this case. Herein, we utilized HSPC, PEG-DSPE, cholesterol and two αvβ3 ligands (RGDm7 and DT4) with different binding rates to build dual-targeting nanovesicles, in an effort to achieve a “fast-binding/slow-unbinding” function. It was demonstrated that the dual-targeting nanovesicles actualized efficient cellular uptake and antitumor effect in vitro both for static and dynamic tumor cells. Besides, the potency of the dual-targeting vesicles for flowing tumor cells was better than that for static tumor cells. Then, a tumor metastasis mice model and a leukemia mice model were established to detect the killing ability of the drug-loaded dual-targeting vesicles to dynamic tumor cells in vivo. The therapy efficacy of the dual-targeting system was higher than other controls including single-targeting ones. Generally, it seems possible to strengthen drug-targeting to dynamic tumor cells via the control of ligand–receptor interaction.

Rapid visualizing and pathological grading of bladder tumor tissues by simple nanodiagnostics

Developing a tissue diagnosis technology to avoid the complicated processes and the usage of expensive reagents while achieving rapid pathological grading diagnosis to provide a better strategy for clinical treatment is an important strategy of tumor diagnose. Herein, we selected the integrin αvβ3 as target based on the analysis of clinical data, and then designed a stable and cancer-targeted selenium nanosystem (RGD@SeNPs) by using RGD polypeptide as the targeting modifier. In vitro experiments showed that RGD@SeNPs could specifically recognized tumor cells, especially in co-culture cells model. The RGD@SeNPs can be used for clinical samples staining without the use of primary and secondary antibody. Fluorescence difference of the tissue specimens staining with RGD@SeNPs could be used to distinguish normal tissues and tumor tissues or estimate different pathological grades of cancer at tissue level. 132 clinical tumor specimens with three types of tumor and 76 non-tumor specimens were examined which verified that the nanoparticles could specific and sensitive distinguish tumor tissue from normal tissue with a specificity of 92% and sensitivity of 96%. These results demonstrate the potential of cancer-targeted RGD@SeNPs as translational nanodiagnostics for rapid visualizing and pathological grading of bladder tumor tissues in clinical specimens.

A magnetism/laser-auxiliary cascaded drug delivery to pulmonary carcinoma

Although high-efficiency targeted delivery is investigated for years, the efficiency of tumor targeting seems still a hard core to smash. To overcome this problem, we design a three-step delivery strategy based on streptavidin–biotin interaction with the help of c(RGDfK), magnetic fields and lasers. The ultrasmall superparamagnetic iron oxide nanoparticles (USIONPs) modified with c(RGDfK) and biotin are delivered at step 1, followed by streptavidin and the doxorubicin (Dox) loaded nanosystems conjugated with biotin at steps 2 and 3, respectively. The delivery systems were proved to be efficient on A549 cells. The co-localization of signal for each step revealed the targeting mechanism. The external magnetic field could further amplify the endocytosis of USPIONs based on c(RGDfK), and magnify the uptake distinctions among different test groups. Based on photoacoustic imaging, laser-heating treatment could enhance the permeability of tumor venous blood vessels and change the insufficient blood flow in cancer. Then, it was noticed in vivo that only three-step delivery with laser-heating and magnetic fields realized the highest tumor distribution of nanosystem. Finally, the magnetism/laser-auxiliary cascaded delivery exhibited the best antitumor efficacy. Generally, this study demonstrated the necessity of combining physical, biological and chemical means of targeting.

RGD-decorated solid lipid nanoparticles enhance tumor targeting, penetration and anticancer effect of asiatic acid

Aim: Asiatic acid (AA) is a promising anticancer agent, however, its delivery to glioblastoma is a major challenge. This work investigates the beneficial therapeutic efficacy of RGD-conjugated solid lipid nanoparticles (RGD-SLNs) for the selective targeting of AA to gliblastoma. Materials & methods: AA-containing RGD-SLNs were prepared using two different PEG-linker size. Targetability and efficacy were tested using monolayer cells and spheroid tumor models. Results: RGD-SLNs significantly improved cytotoxicity of AA against U87-MG monolayer cells and enhanced cellular uptake compared with non-RGD-containing SLNs. In spheroid models, AA-containing RGD-SLNs showed superior control in tumor growth, improved cytotoxicity and enhanced spheroid penetration when compared with AA alone or non-RGD-containing SLNs. Conclusion: This study illustrates the potential of AA-loaded RGD-SLNs as efficacious target-specific treatment for glioblastoma.

MicroRNA Nanotherapeutics for Lung Targeting. Insights into Pulmonary Hypertension

In this review, the potential future role of microRNA-based therapies and their specific application in lung diseases is reported with special attention to pulmonary hypertension. Current limitations of these therapies will be pointed out in order to address the challenges that they need to face to reach clinical applications. In this context, the encapsulation of microRNA-based therapies in nanovectors has shown improvements as compared to chemically modified microRNAs toward enhanced stability, efficacy, reduced side effects, and local administration. All these concepts will contextualize in this review the recent achievements and expectations reported for the treatment of pulmonary hypertension.

Design of Magnetic-Plasmonic Nanoparticle Assemblies via Interface Engineering of Plasmonic Shells for Targeted Cancer Cell Imaging and Separation

Magnetic-plasmonic nanoparticles have received considerable attention for widespread applications. These nanoparticles (NPs) exhibiting surface-enhanced Raman scattering (SERS) activities are developed due to their potential in bio-sensing applicable in non-destructive and sensitive analysis with target-specific separation. However, it is challenging to synthesize these NPs that simultaneously exhibit low remanence, maximized magnetic content, plasmonic coverage with abundant hotspots, and structural uniformity. Here, a method that involves the conjugation of a magnetic template with gold seeds via chemical binding and seed-mediated growth is proposed, with the objective of obtaining plasmonic nanostructures with abundant hotspots on a magnetic template. To obtain a clean surface for directly functionalizing ligands and enhancing the Raman intensity, an additional growth step of gold (Au) and/or silver (Ag) atoms is proposed after modifying the Raman molecules on the as-prepared magnetic-plasmonic nanoparticles. Importantly, one-sided silver growth occurred in an environment where gold facets are blocked by Raman molecules; otherwise, the gold growth is layer-by-layer. Moreover, simultaneous reduction by gold and silver ions allowed for the formation of a uniform bimetallic layer. The enhancement factor of the nanoparticles with a bimetallic layer is approximately 10⁷ . The SERS probes functionalized cyclic peptides are employed for targeted cancer-cell imaging and separation.

Topical Application of Hyaluronic Acid-RGD Peptide-Coated Gelatin/Epigallocatechin-3 Gallate (EGCG) Nanoparticles Inhibits Corneal Neovascularization Via Inhibition of VEGF Production

Neovascularization (NV) of the cornea disrupts vision which leads to blindness. Investigation of antiangiogenic, slow-release and biocompatible approaches for treating corneal NV is of great importance. We designed an eye drop formulation containing gelatin/epigallocatechin-3-gallate (EGCG) nanoparticles (NPs) for targeted therapy in corneal NV. Gelatin-EGCG self-assembled NPs with hyaluronic acid (HA) coating on its surface (named GEH) and hyaluronic acid conjugated with arginine-glycine-aspartic acid (RGD) (GEH-RGD) were synthesized. Human umbilical vein endothelial cells (HUVECs) were used to evaluate the antiangiogenic effect of GEH-RGD NPs in vitro. Moreover, a mouse model of chemical corneal cauterization was employed to evaluate the antiangiogenic effects of GEH-RGD NPs in vivo. GEH-RGD NP treatment significantly reduced endothelial cell tube formation and inhibited metalloproteinase (MMP)-2 and MMP-9 activity in HUVECs in vitro. Topical application of GEH-RGD NPs (once daily for a week) significantly attenuated the formation of pathological vessels in the mouse cornea after chemical cauterization. Reduction in both vascular endothelial growth factor (VEGF) and MMP-9 protein in the GEH-RGD NP-treated cauterized corneas was observed. These results confirm the molecular mechanism of the antiangiogenic effect of GEH-RGD NPs in suppressing pathological corneal NV.

Anisotropic active ligandations in siRNA-Loaded hybrid nanodiscs lead to distinct carcinostatic outcomes by regulating nano-bio interactions

Active targeting modification is one of the foremost nanomedicine strategies for the efficacy improvement. Compared to the homogeneous ligandation on spherical nanocarriers, non-spherical nanomedicines usually make the ligand modification more complicated. The modified ligands always exhibit anisotropy and heterogeneity. However, there is very little systematic study on these diversified anisotropic modifications. The efficacy difference and underlying mechanism were still unclear. Here, we separately fabricated hybrid nanodiscs (NDs) conjugated with cRGD on the edge and plane surfaces to engineer two anisotropic targeting nanocarriers (E-cRGD-NDs and P-cRGD-NDs, respectively) for gene delivery. The ligand anisotropy endowed NDs with diversified cellular interactions, and caused different efficacies between E-cRGD-NDs and P-cRGD-NDs. Of note, E-cRGD-NDs showed significant superiority in siRNA loading, cellular uptake, silence efficiency, protein expression and even in vivo efficacy. The mechanism investigation revealed the functional anisotropy specifically for E-cRGD-NDs. The edge modification of cRGD efficiently separated the targeting and siRNA loading domains, maximizing their respective functions. These findings reflected the unique effect of ligand anisotropy, also provided a new strategy for the targeting screening of extensive nanomedicines.

Design, preparation and evaluation of different branched biotin modified liposomes for targeting breast cancer

A series of liposome ligands (Bio-Chol, Bio-Bio-Chol, tri-Bio-Chol and tetra-Bio-Chol) modified by different branched biotins that can recognize the SMVT receptors over-expressed in breast cancer cells were synthesized. And four liposomes (Bio-Lip, Bio-Bio-Lip, tri-Bio-Lip and tetra-Bio-Lip) modified by above mentioned ligands as well as the unmodified liposome (Lip) were prepared to study the targeting ability for breast cancer. The cytotoxicity study and apoptosis assay of paclitaxel-loaded liposomes showed that tri-Bio-Lip had the strongest anti-proliferative effect on breast cancer cells. The cellular uptake studies on mice breast cancer cells (4T1) and human breast cancer cells (MCF-7) indicated tri-Bio-Lip possessed the strongest internalization ability, which was 5.21 times of Lip, 2.60 times of Bio-Lip, 1.67 times of Bio-Bio-Lip and 1.17 times of tetra-Bio-Lip, respectively. Moreover, the 4T1 tumor-bearing BALB/c mice were used to evaluate the in vivo targeting ability. The data showed the enrichment of liposomes at tumor sites were tri-Bio-Lip > tetra-Bio-Lip > Bio-Bio-Lip > Bio-Lip > Lip, which were consistent with the results of in vitro targeting studies. In conclusion, increasing the density of targeting molecules on the surface of liposomes can effectively enhance the breast cancer targeting ability, and the branching structure and spatial distance of biotin residues may also have an important influence on the affinity to SMVT receptors. Therefore, tri-Bio-Lip could be a promising drug delivery system for targeting breast cancer.

Liposomes modified with bio-substances for cancer treatment

In recent years, liposomes have been used in the field of biomedicine and have achieved many significant results.

Role of Surface RGD Patterns on Protein Nanocages in Tumor Targeting Revealed Using Precise Discrete Models

The effectiveness of active targeting in cancer nanomedicine is becoming increasingly more debatable. Here, the role of the ligand functionalization patterns (number and distribution) on nanoparticle surfaces in tumor targeting is investigated using a 9 nm sized miniferritin protein nanocage, Dps modified with Arg-Gly-Asp (RGD) ligands whose functionalization patterns are precisely controlled. In vitro and in vivo experiments show that RGD modification endows Dps with tumor targeting capacity no matter what the surface pattern is. The tumor targeting of 2-ligand Dps, which is better than that of 1-ligand Dps, rivals or surpasses that of the 12- or 24-ligand Dps. The 12-ligand Dps with clustered RGD distribution shows 2.3 times the in vivo targeting efficiency of that with even distribution. The surface ligand pattern effects are correlated at least to receptor clustering and opsonization. This study provides insights into the understanding of the controversial findings on active tumor targeting in the literature and highlights the necessity of precise functionalization to achieve optimal active targeting in developing cancer nanomedicine.

Cyclic RGD-Functionalized and Disulfide-Crosslinked Iodine-Rich Polymersomes as a Robust and Smart Theranostic Agent for Targeted CT Imaging and Chemotherapy of Tumor

There is tremendous interest in integrating CT imaging with chemotherapy; however, reported iodine-based nanosystems such as nanogels and nano-emulsions display typically reduced contrast coefficient, low drug loading and stability, and poor targetability. Here, cRGD-functionalized disulfide-crosslinked iodine-rich polymersomes (cRGD-XIPs) were designed as a novel, robust and smart theranostic agent and investigated for targeted CT imaging and chemotherapy of malignant tumors. Methods: cRGD-XIPs were prepared from co-self-assembly of poly(ethylene glycol)-b-poly(dithiolane trimethylene carbonate-co-iodinated trimethylene carbonate) (PEG-P(DTC-IC)) and cRGD-PEG-P(DTC-IC) block copolymers. In vitro and in vivo CT contrast effect of cRGD-XIPs was studied using α_vβ₃-overexpressing B16 melanoma as a tumor model in comparison with clinical agent iohexol. The therapeutic efficacy of doxorubicin-loaded cRGD-XIPs (cRGD-XIPs-Dox) to B16 melanoma was investigated and compared with XIPs-Dox (non-targeted), cRGD-IPs-Dox (non-crosslinked) and free Dox. Results: cRGD-XIPs were formed with 55.5 wt.% iodine and ca. 90 nm in diameter. cRGD-XIPs-Dox with a Dox loading of 15.3 wt.% bared superior colloidal stability and reduction-responsive drug release. Notably, blank cRGD-XIPs showed a maximum-tolerated dose (MTD) > 400 mg iodine equiv./kg while cRGD-XIPs-Dox had an MTD > 150 mg Dox equiv./kg, ca. 15-fold improvement over free Dox. cRGD-XIPs revealed superior CT contrast effect and achieved 46.5- and 24.0-fold better enhancement of CT imaging of B16 melanoma than iohexol at 4 h following intratumoral and intravenous injection, respectively. cRGD-XIPs-Dox displayed an elimination half-life of 6.5 h and an elevated accumulation of 6.68% ID/g in the tumors. Furthermore, cRGD-XIPs-Dox was significantly more effective than XIPs-Dox and cRGD-XPs-Dox in inhibiting growth of B16 melanoma model. Conclusion: This proof-of-concept study demonstrates that cRGD-XIPs are a robust, non-toxic and smart polymeric theranostic agent that can not only significantly enhance CT imaging of tumors but also mediate efficient tumor-targeted chemotherapy. XIPs offer a unique and safe platform for theranostic polymersomes that pre-select patients using CT imaging prior to targeted chemotherapy with the same system.

Exploring the relationship of hyaluronic acid molecular weight and active targeting efficiency for designing hyaluronic acid-modified nanoparticles

Although it is reported that the targeting ability of hyaluronic acid (HA)-based nanoparticles (NPs) is molecular weight (MW) dependent, the influence of HA MW on targeting efficiency of HA-functionalized NPs and the underlying mechanism remain elusive. In this study, we constituted three HA-functionalized Dox-loaded NPs (Dox/HCVs) different HA MWs (7, 63, and 102 kDa) and attempted to illustrate the effects of HA MW on the targeting efficiency. The three Dox/HCVs had similar physiochemical and pharmaceutical characteristics, but showed different affinity to CD44 receptor. Furthermore, Dox/HCV-63 exerted the best targeting effect and the highest cytotoxicity compared with Dox/HCV-7 and Dox/HCV-102. It was interesting to found that both the HA-CD44 binding affinity and induced CD44 clustering by HA-based NPs were HA MW-dependent, the two of which determine the apparent targeting efficacy of Dox/HCV NPs in the conflicting directions. Those results laid a good foundation for rationally designing HA-based NPs in cancer therapy.

DnBP-induced thyroid disrupting activities in GH3 cells via integrin αvβ3 and ERK1/2 activation

Di-n-butylphthalate (DnBP) exhibits alarming thyroid disrupting activities. However, the toxic mechanism of DnBP is not completely understood. In this study, we investigated the mechanism of DnBP in thyroid disruption. Rat pituitary tumor cell lines (GH3) were treated with DnBP in different scenarios, and cell viabilities, target gene transcriptions and protein levels were measured accordingly. The results showed that after treatment with DnBP (20 μmol/L), cell proliferation increased to 114.69% (p < 0.01) and c-fos gene was up-regulated by 1.57-fold (p < 0.01). Both nuclear thyroid hormone receptor β (TRβ) and membrane TR (integrin α_v and integrin β₃) genes were up-regulated by 1.31-, 1.08- and 2.39-fold (p < 0.01), respectively, the latter was inhibited by Arg-Gly-Asp (RGD) peptides; the macromolecular DnBP-BSA was unable to bind nuclear TRs, but still promoted cell proliferation to 104.18% and up-regulated c-fos by 2.99-fold (p < 0.01); after silencing TRβ gene, cell proliferation (106.64%, p < 0.05) and up-regulation of c-fos (1.23-fold, p < 0.01) were also observed. All of these findings indicated the existence of non-genomic pathway for DnBP-induced thyroid disruption. Finally, DnBP activated the downstream extracellular regulated protein kinases (ERK1/2) pathway, up-regulating Mapk1 (1.15-, p < 0.05), Mapk3 (1.26-fold, p < 0.01) and increasing protein levels of p-ERK (p < 0.01); notably, DnBP-induced ERK1/2 activation along with c-fos up-regulation were attenuated by PD98059 (ERK1/2 inhibitor). Taken together, it could be suggested that integrin α_vβ₃ and ERK1/2 pathway play significant roles in DnBP-induced thyroid disruption, and this novel mechanism warrants further investigation in living organisms.

Apolipoprotein E Peptide-Directed Chimeric Polymersomes Mediate an Ultrahigh-Efficiency Targeted Protein Therapy for Glioblastoma

The inability to cross the blood-brain barrier (BBB) prevents nearly all chemotherapeutics and biotherapeutics from the effective treatment of brain tumors, rendering few improvements in patient survival rates to date. Here, we report that apolipoprotein E peptide [ApoE, (LRKLRKRLL)₂C] specifically binds to low-density lipoprotein receptor members (LDLRs) and mediates superb BBB crossing and highly efficient glioblastoma (GBM)-targeted protein therapy in vivo. The in vitro BBB model studies reveal that ApoE induces 2.2-fold better penetration of the immortalized mouse brain endothelial cell line (bEnd.3) monolayer for chimeric polymersomes (CP) compared to Angiopep-2, the best-known BBB-crossing peptide used in clinical trials for GBM therapy. ApoE-installed CP (ApoE-CP) carrying saporin (SAP) displays a highly specific and potent antitumor effect toward U-87 MG cells with a low half-maximum inhibitory concentration of 14.2 nM SAP. Notably, ApoE-CP shows efficient BBB crossing as well as accumulation and penetration in orthotopic U-87 MG glioblastoma. The systemic administration of SAP-loaded ApoE-CP causes complete growth inhibition of orthotopic U-87 MG GBM without eliciting any observable adverse effects, affording markedly improved survival benefits. ApoE peptide provides an ultrahigh-efficiency targeting strategy for GBM therapy.

Preparation and Characterization of Functionalized Graphene Oxide Carrier for siRNA Delivery

A successful siRNA delivery system is dependent on the development of a good siRNA carrier. Graphene oxide (GO) has gained great attention as a promising nanocarrier in recent years. It has been reported that GO could be used to deliver a series of drugs including synthetic compounds, proteins, antibodies, and genes. Our previous research indicated that functionalized GO could deliver siRNA into tumor cells and induce a gene silencing effect, to follow up the research, in this research, GO-R8/cRGDfV(GRcR) was designed and prepared for VEGF-siRNA delivery as a novel carrier. The Zeta potential and particle size of the new designed GRcR carrier was measured at (29.46 ± 5.32) mV and (135.7 ± 3.3) nm respectively, and after transfection, the VEGF mRNA level and protein expression level were down-regulated by 48.22% (p < 0.01) and 38.3% (p < 0.01) in HeLa cells, respectively. The fluorescent images of the treated BALB/c nude mice revealed that GRcR/VEGF-siRNA could conduct targeted delivery of VEGF-siRNA into tumor tissues and showed a gene silencing effect as well as a tumor growth inhibitory effect (p < 0.01) in vivo. Further studies showed that GRcR/VEGF-siRNA could effectively inhibit angiogenesis by suppressing VEGF expression. Histology and immunohistochemistry studies demonstrated that GRcR/VEGF-siRNA could inhibit tumor tissue growth effectively and have anti-angiogenesis activity, which was the result of VEGF protein downregulation. Both in vitro and in vivo results demonstrated that GRcR/VEGF-siRNA could be used as an ideal nonviral tumor-targeting vector for VEGF-siRNA delivery in gene therapy.

The Improved Delivery to Breast Cancer Based on a Novel Nanocarrier Modified with High-Affinity Peptides Discovered by Phage Display

Ligand-targeted nanosystems have the potential to realize site-specific tumor therapy and alleviate unwanted side effects of many chemotherapeutic agents, and one of the most key issues seems to be the construction of an effective nanocarrier. Based on different processes of phage display techniques, 38 cell-binding peptides and 32 cell-internalizing peptides are discovered. Four of these ligand peptides [FIPFDPMSMRWE (FIP), NASSFPTNSRWA (NAS), GLHTSATNLYLH (GLH), and ALAVAPSRWWNE (ALA), respectively] exhibit high affinity to MCF7 human breast cancer cells. Among them, NAS and ALA are reported for the first time, whose affinities are 20.6 and 76.3 times that of the random peptide control, respectively. Both NAS and ALA modifications to doxorubicin-loaded lipid nanosytems [LP(DOX)] show stronger tumor inhibition, longer animal survival time, and less body weight loss, compared to unmodified or control peptide modified nanosystems, on an MCF7 tumor-bearing mouse model. In conclusion, the cell-binding peptide NAS and cell-internalizing peptide ALA can be used for ligand-targeted delivery of antitumor drugs. It seems that the in vivo antitumor effect of these ligand-targeted nanosystems is closely related to their ligand-cell affinity, but fairly tolerant of the ligand types.

Development of High-Functionality and -Quality Lipids with RGD Peptide Ligands: Application for PEGylated Liposomes and Analysis of Intratumoral Distribution in a Murine Colon Cancer Model

High-functionality and -quality (HFQ) lipids have a discrete molecular weight and good water dispersibility and can be produced by solid-phase peptide synthesis. Therefore, HFQ lipids are a promising material for the preparation of ligand-grafted PEGylated liposomes. Recently, we have reported serine-glycine repeated peptides ((SG) _n) as a spacer of HFQ lipids and to substitute a conventional PEG spacer. We demonstrated the advantage of using (SG) _n spacers for peptide ligand presentation on the liposomal surface in vitro; however, the use of (SG) _n spacers in ligand-grafted PEGylated liposomes in vivo has not been validated. The aim of this study was to validate the in vivo targeting ability of HFQ lipid-grafted PEGylated liposomes. We synthesized lipids containing GRGDS (RGD-(SG) _n-lipid) to target integrin α_vβ₃ and prepared RGD-(SG) _n/PEGylated liposomes. Subsequently, their cellular uptake characteristics in murine colon carcinoma (Colon-26) cells were evaluated. Two-color imaging of liposomes and tumor blood vessels following tissue clearing was performed to examine the spatial intratumoral distribution of liposomes. RGD-(SG)₅/PEGylated liposomes were selectively associated with the cells in vitro. In vivo analysis of intratumoral distribution following tissue clearing revealed the superior targeting ability of RGD-(SG)₅/PEGylated liposomes compared with that of conventional RGD-PEG₂₀₀₀/PEGylated liposomes for both tumor tissues and tumor blood vessels. We successfully synthesized RGD-HFQ lipids to prepare RGD-grafted PEGylated liposomes for the efficient targeting of integrin α_vβ₃-expressing cells. To the best of our knowledge, this is the first report of the intratumoral distribution of ligand-grafted PEGylated liposomes by two-color imaging following tissue clearing.