Co-administration of dual-targeting nanoparticles with penetration enhancement peptide for antiglioblastoma therapy

Targeted Ferroptosis-Immunotherapy Synergy: Enhanced Antiglioma Efficacy with Hybrid Nanovesicles Comprising NK Cell-Derived Exosomes and RSL3-Loaded Liposomes

Ferroptosis therapy and immunotherapy have been widely used in cancer treatment. However, nonselective induction of ferroptosis in tumors is prone to immunosuppression, limiting the therapeutic effect of ferroptosis cancer treatment. To address this issue, this study reports a customized hybrid nanovesicle composed of NK cell-derived extracellular versicles and RSL3-loaded liposomes (hNRVs), aiming to establish a positive cycle between ferroptosis therapy and immunotherapy. Thanks to the enhanced permeability and retention effect and the tumor homing characteristics of NK exosomes, our data indicate that hNRVs can actively accumulate in tumors and enhance cellular uptake. FASL, IFN-γ, and RSL3 are released into the tumor microenvironment, where FASL derived from NK cells effectively lyses tumor cells. RSL3 downregulates the expression of GPX4 in the tumor, leading to the accumulation of LPO and ROS, and promotes ferroptosis in tumor cells. The accumulation of IFN-γ and TNF-α stimulates the maturation of dendritic cells and effectively induces the inactivation of GPX4, promoting lipid peroxidation, making them sensitive to ferroptosis and indirectly promoting the occurrence of ferroptosis. This study highlights the role of the customized hNRV platform in enhancing the effectiveness of synergistic treatment with selective delivery of ferroptosis inducers and immune activation against glioma without causing additional side effects on healthy organs.

Next-generation agents for fluorescence-guided glioblastoma surgery

Glioblastoma is a fast-growing and aggressive form of brain cancer. Even with maximal treatment, patients show a low median survival and are often subjected to a high recurrence incidence. The currently available treatments require multimodal management, including maximal safe surgical resection, followed by radiation and chemotherapy. Because of the infiltrative glioblastoma nature, intraoperative differentiation of cancer tissue from normal brain parenchyma is very challenging, and this accounts for the low rate of complete tumor resection. For these reasons, clinicians have increasingly used various intraoperative adjuncts to improve surgical results, such as fluorescent agents. However, most of the existing fluorophores show several limitations such as poor selectivity, photostability, photosensitization and high costs. This could limit their application to successfully improve glioblastoma resection. In the present perspective, we highlight the possibility to develop next-generation fluorescent tools able to more selectively label cancer cells during surgical resection.

Functionalized nanoparticles crossing the brain-blood barrier to target glioma cells

Glioma is the most common tumor of the central nervous system (CNS), with a 5-year survival rate of <35%. Drug therapy, such as chemotherapeutic and immunotherapeutic agents, remains one of the main treatment modalities for glioma, including temozolomide, doxorubicin, bortezomib, cabazitaxel, dihydroartemisinin, immune checkpoint inhibitors, as well as other approaches such as siRNA, ferroptosis induction, etc. However, the filter function of the blood-brain barrier (BBB) reduces the amount of drugs needed to effectively target CNS tumors, making it one of the main reasons for poor drug efficacies in glioma. Thus, finding a suitable drug delivery platform that can cross the BBB, increase drug aggregation and retainment in tumoral areas and avoid accumulation in non-targeted areas remains an unsolved challenge in glioma drug therapy. An ideal drug delivery system for glioma therapy should have the following features: (1) prolonged drug life in circulation and effective penetration through the BBB; (2) adequate accumulation within the tumor (3) controlled-drug release modulation; (4) good clearance from the body without significant toxicity and immunogenicity, etc. In this regard, due to their unique structural features, nanocarriers can effectively span the BBB and target glioma cells through surface functionalization, providing a new and effective strategy for drug delivery. In this article, we discuss the characteristics and pathways of different nanocarriers for crossing the BBB and targeting glioma by listing different materials for drug delivery platforms, including lipid materials, polymers, nanocrystals, inorganic nanomaterials, etc.

Lactoferrin and Nanotechnology: The Potential for Cancer Treatment

Lactoferrin (Lf)-a glycoprotein of the transferrin family-has been investigated as a promising molecule with diverse applications, including infection inhibition, anti-inflammation, antioxidant properties and immune modulation. Along with that, Lf was found to inhibit the growth of cancerous tumors. Owing to unique properties such as iron-binding and positive charge, Lf could interrupt the cancer cell membrane or influence the apoptosis pathway. In addition, being a common mammalian excretion, Lf offers is promising in terms of targeting delivery or the diagnosis of cancer. Recently, nanotechnology significantly enhanced the therapeutic index of natural glycoproteins such as Lf. Therefore, in the context of this review, the understanding of Lf is summarized and followed by different strategies of nano-preparation, including inorganic nanoparticles, lipid-based nanoparticles and polymer-based nanoparticles in cancer management. At the end of the study, the potential future applications are discussed to pave the way for translating Lf into actual usage.

Polymersome-based protein drug delivery - quo vadis?

Protein-based therapeutics are an attractive alternative to established therapeutic approaches and represent one of the fastest growing families of drugs. While many of these proteins can be delivered using established formulations, the intrinsic sensitivity of proteins to denaturation sometimes calls for a protective carrier to allow administration. Historically, lipid-based self-assembled structures, notably liposomes, have performed this function. After the discovery of polymersome-based targeted drug-delivery systems, which offer manifold advantages over lipid-based structures, the scientific community expected that such systems would take the therapeutic world by storm. However, no polymersome formulations have been commercialised. In this review article, we discuss key obstacles for the sluggish translation of polymersome-based protein nanocarriers into approved pharmaceuticals, which include limitations imparted by the use of non-degradable polymers, the intricacies of polymersome production methods, and the complexity of the in vivo journey of polymersomes across various biological barriers. Considering this complex subject from a polymer chemist's point of view, we highlight key areas that are worthy to explore in order to advance polymersomes to a level at which clinical trials become worthwhile and translation into pharmaceutical and nanomedical applications is realistic.

Capturing the spatial and temporal dynamics of tumor stroma for on-chip optimization of microenvironmental targeting nanomedicine

Malignant cells grow in a complex microenvironment that plays a key role in cancer progression. The "dynamic reciprocity" existing between cancer cells and their microenvironment is involved in cancer differentiation, proliferation, invasion, metastasis, and drug response. Therefore, understanding the molecular mechanisms underlying the crosstalk between cancer cells and their surrounding tissue (i.e., tumor stroma) and how this interplay affects the disease progression is fundamental to design and validate novel nanotherapeutic approaches. As an important regulator of tumor progression, metastasis and therapy resistance, the extracellular matrix of tumors, the acellular component of the tumor microenvironment, has been identified as very promising target of anticancer treatment, revolutionizing the traditional therapeutic paradigm that sees the neoplastic cells as the preferential objective to fight cancer. To design and to validate such a target therapy, advanced 3D preclinical models are necessary to correctly mimic the complex, dynamic and heterogeneous tumor microenvironment. In addition, the recent advancement in microfluidic technology allows fine-tuning and controlling microenvironmental parameters in tissue-on-chip devices in order to emulate the in vivo conditions. In this review, after a brief description of the origin of tumor microenvironment heterogeneity, some examples of nanomedicine approaches targeting the tumor microenvironment have been reported. Further, how advanced 3D bioengineered tumor models coupled with a microfluidic device can improve the design and testing of anti-cancer nanomedicine targeting the tumor microenvironment has been discussed. We highlight that the presence of a dynamic extracellular matrix, able to capture the spatiotemporal heterogeneity of tumor stroma, is an indispensable requisite for tumor-on-chip model and nanomedicine testing.

Tumor microenvironment penetrating chitosan nanoparticles for elimination of cancer relapse and minimal residual disease

Chitosan and its derivatives are among biomaterials with numerous medical applications, especially in cancer. Chitosan is amenable to forming innumerable shapes such as micelles, niosomes, hydrogels, nanoparticles, and scaffolds, among others. Chitosan derivatives can also bring unprecedented potential to cross numerous biological barriers. Combined with other biomaterials, hybrid and multitasking chitosan-based systems can be realized for many applications. These include controlled drug release, targeted drug delivery, post-surgery implants (immunovaccines), theranostics, biosensing of tumor-derived circulating materials, multimodal systems, and combination therapy platforms with the potential to eliminate bulk tumors as well as lingering tumor cells to treat minimal residual disease (MRD) and recurrent cancer. We first introduce different formats, derivatives, and properties of chitosan. Next, given the barriers to therapeutic efficacy in solid tumors, we review advanced formulations of chitosan modules as efficient drug delivery systems to overcome tumor heterogeneity, multi-drug resistance, MRD, and metastasis. Finally, we discuss chitosan NPs for clinical translation and treatment of recurrent cancer and their future perspective.

Peptides as Pharmacological Carriers to the Brain: Promises, Shortcomings and Challenges

Central nervous system (CNS) diseases are among the most difficult to treat, mainly because the vast majority of the drugs fail to cross the blood-brain barrier (BBB) or to reach the brain at concentrations adequate to exert a pharmacological activity. The obstacle posed by the BBB has led to the in-depth study of strategies allowing the brain delivery of CNS-active drugs. Among the most promising strategies is the use of peptides addressed to the BBB. Peptides are versatile molecules that can be used to decorate nanoparticles or can be conjugated to drugs, with either a stable link or as pro-drugs. They have been used to deliver to the brain both small molecules and proteins, with applications in diverse therapeutic areas such as brain cancers, neurodegenerative diseases and imaging. Peptides can be generally classified as receptor-targeted, recognizing membrane proteins expressed by the BBB microvessels (e.g., Angiopep2, CDX, and iRGD), "cell-penetrating peptides" (CPPs; e.g. TAT_47-57, SynB1/3, and Penetratin), undergoing transcytosis through unspecific mechanisms, or those exploiting a mixed approach. The advantages of peptides have been extensively pointed out, but so far few studies have focused on the potential negative aspects. Indeed, despite having a generally good safety profile, some peptide conjugates may display toxicological characteristics distinct from those of the peptide itself, causing for instance antigenicity, cardiovascular alterations or hemolysis. Other shortcomings are the often brief lifetime in vivo, caused by the presence of peptidases, the vulnerability to endosomal/lysosomal degradation, and the frequently still insufficient attainable increase of brain drug levels, which remain below the therapeutically useful concentrations. The aim of this review is to analyze not only the successful and promising aspects of the use of peptides in brain targeting but also the problems posed by this strategy for drug delivery.

Beyond Formulation: Contributions of Nanotechnology for Translation of Anticancer Natural Products into New Drugs

Nature is the largest pharmacy in the world. Doxorubicin (DOX) and paclitaxel (PTX) are two examples of natural-product-derived drugs employed as first-line treatment of various cancer types due to their broad mechanisms of action. These drugs are marketed as conventional and nanotechnology-based formulations, which is quite curious since the research and development (R&D) course of nanoformulations are even more expensive and prone to failure than the conventional ones. Nonetheless, nanosystems are cost-effective and represent both novel and safer dosage forms with fewer side effects due to modification of pharmacokinetic properties and tissue targeting. In addition, nanotechnology-based drugs can contribute to dose modulation, reversion of multidrug resistance, and protection from degradation and early clearance; can influence the mechanism of action; and can enable drug administration by alternative routes and co-encapsulation of multiple active agents for combined chemotherapy. In this review, we discuss the contribution of nanotechnology as an enabling technology taking the clinical use of DOX and PTX as examples. We also present other nanoformulations approved for clinical practice containing different anticancer natural-product-derived drugs.

An update on dual targeting strategy for cancer treatment

The key issue in the treatment of solid tumors is the lack of efficient strategies for the targeted delivery and accumulation of therapeutic cargoes in the tumor microenvironment (TME). Targeting approaches are designed for more efficient delivery of therapeutic agents to cancer cells while minimizing drug toxicity to normal cells and off-targeting effects, while maximizing the eradication of cancer cells. The highly complicated interrelationship between the physicochemical properties of nanoparticles, and the physiological and pathological barriers that are required to cross, dictates the need for the success of targeting strategies. Dual targeting is an approach that uses both purely biological strategies and physicochemical responsive smart delivery strategies to increase the accumulation of nanoparticles within the TME and improve targeting efficiency towards cancer cells. In both approaches, either one single ligand is used for targeting a single receptor on different cells, or two different ligands for targeting two different receptors on the same or different cells. Smart delivery strategies are able to respond to triggers that are typical of specific disease sites, such as pH, certain specific enzymes, or redox conditions. These strategies are expected to lead to more precise targeting and better accumulation of nano-therapeutics. This review describes the classification and principles of dual targeting approaches and critically reviews the efficiency of dual targeting strategies, and the rationale behind the choice of ligands. We focus on new approaches for smart drug delivery in which synthetic and/or biological moieties are attached to nanoparticles by TME-specific responsive linkers and advanced camouflaged nanoparticles.

Strategies to improve the EPR effect: A mechanistic perspective and clinical translation

Many efforts have been made to achieve targeted delivery of anticancer drugs to enhance their efficacy and to reduce their adverse effects. These efforts include the development of nanomedicines as they can selectively penetrate through tumor blood vessels through the enhanced permeability and retention (EPR) effect. The EPR effect was first proposed by Maeda and co-workers in 1986, and since then various types of nanoparticles have been developed to take advantage of the phenomenon with regards to drug delivery. However, the EPR effect has been found to be highly variable and thus unreliable due to the complex tumor microenvironment. Various physical and pharmacological strategies have been explored to overcome this challenge. Here, we review key advances and emerging concepts of such EPR-enhancing strategies. Furthermore, we analyze 723 clinical trials of nanoparticles with EPR enhancers and discuss their clinical translation.

Local Delivery and Glioblastoma: Why Not Combining Sustained Release and Targeting?

Glioblastoma is one of the most aggressive brain tumors and is associated with a very low overall median survival despite the current treatment. The standard of care used in clinic is the Stupp's protocol which consists of a maximal resection of the tumor when possible, followed by radio and chemotherapy using temozolomide. However, in most cases, glioblastoma cells infiltrate healthy tissues and lead to fatal recurrences. There are a lot of hurdles to overcome in the development of new therapeutic strategies such as tumor heterogeneity, cell infiltration, alkylating agent resistance, physiological barriers, etc., and few treatments are on the market today. One of them is particularly appealing because it is a local therapy, which does not bring additional invasiveness since tumor resection is included in the gold standard treatment. They are implants: the Gliadel^® wafers, which are deposited post-surgery. Nevertheless, in addition to presenting important undesirable effects, it does not bring any major benefit in the therapy despite the strategy being particularly attractive. The purpose of this review is to provide an overview of recent advances in the development of innovative therapeutic strategies for glioblastoma using an implant-type approach. The combination of this local strategy with effective targeting of the tumor microenvironment as a whole, also developed in this review, may be of interest to alleviate some of the obstacles encountered in the treatment of glioblastoma.

Nanomedicine Strategies to Circumvent Intratumor Extracellular Matrix Barriers for Cancer Therapy

The dense and heterogeneous physical network of the extracellular matrix (ECM) in tumors represents a formidable barrier that limits intratumor drug delivery and the therapeutic efficacy of many anticancer therapies. Here, the two major nanomedicine strategies to circumvent intratumor ECM barriers: regulating the physiochemical properties of nanomedicines and remodeling the components and structure of the ECM are summarized. Nanomedicines can be rationally regulated by optimizing physiochemical properties or designed with biomimetic features to promote ECM permeation capability. Meanwhile, they can also be designed to remodel the ECM by modulating signaling pathways or destroying the components and architecture of the ECM via chemical, biological, or physical treatments. These efforts produce profound improvements in intratumor drug delivery and anticancer efficacy. Moreover, to aid in their anticancer efficacy, feasible approaches for improving ECM-circumventing nanomedicines are proposed.

Combined integrin αvβ3 and lactoferrin receptor targeted docetaxel liposomes enhance the brain targeting effect and anti-glioma effect

The integrin α_vβ₃ receptor and Lactoferrin receptor (LfR) are over-expressed in both cerebral microvascular endothelial cells and glioma cells. RGD tripeptide and Lf can specifically bind with integrin α_vβ₃ receptor and LfR, respectively. In our study, RGD and Lf dual-modified liposomes loaded with docetaxel (DTX) were designed to enhance the brain targeting effect and treatment of glioma. Our in vitro studies have shown that RGD-Lf-LP can significantly enhance the cellular uptake of U87 MG cells and human cerebral microvascular endothelial cells (hCMEC/D3) when compared to RGD modified liposomes (RGD-LP) and Lf modified liposomes (Lf-LP). Free RGD and Lf competitively reduced the cellular uptake of RGD-Lf-LP, in particular, free RGD played a main inhibitory effect on cellular uptake of RGD-Lf-LP in U87 MG cells, yet free Lf played a main inhibitory effect on cellular uptake of RGD-Lf-LP in hCMEC/D3 cells. RGD-Lf-LP can also significantly increase penetration of U87 MG tumor spheroids, and RGD modification plays a dominating role on promoting the penetration of U87 MG tumor spheroids. The results of in vitro BBB model were shown that RGD-Lf-LP-C6 obviously increased the transport of hCMEC/D3 cell monolayers, and Lf modification plays a dominating role on increasing the transport of hCMEC/D3 cell monolayers. In vivo imaging proved that RGD-Lf-LP shows stronger targeting effects for brain orthotopic gliomas than that of RGD-LP and Lf-LP. The result of tissue distribution confirmed that RGD-LF-LP-DTX could significantly increase brain targeting after intravenous injection. Furthermore, RGD-LF-LP-DTX (a dose of 5 mg kg⁻¹ DTX) could significantly prolong the survival time of orthotopic glioma-bearing mice. In summary, RGD and LF dual modification are good combination for brain targeting delivery, RGD-Lf-LP-DTX could enhance brain targeting effects, and is thus a promising chemotherapeutic drug delivery system for treatment of glioma.

Development of Encapsulation Strategies and Composite Edible Films to Maintain Lactoferrin Bioactivity: A Review

Lactoferrin (LF) is a whey protein with various and valuable biological activities. For this reason, LF has been used as a supplement in formula milk and functional products. However, it must be considered that the properties of LF can be affected by technological treatments and gastrointestinal conditions. In this article, we have revised the literature published on the research done during the last decades on the development of various technologies, such as encapsulation or composite materials, to protect LF and avoid its degradation. Multiple compounds can be used to conduct this protective function, such as proteins, including those from milk, or polysaccharides, like alginate or chitosan. Furthermore, LF can be used as a component in complexes, nanoparticles, hydrogels and emulsions, to encapsulate, protect and deliver other bioactive compounds, such as essential oils or probiotics. Additionally, LF can be part of systems to deliver drugs or to apply certain therapies to target cells expressing LF receptors. These systems also allow improving the detection of gliomas and have also been used for treating some pathologies, such as different types of tumours. Finally, the application of LF in edible and active films can be effective against some contaminants and limit the increase of the natural microbiota present in meat, for example, becoming one of the most interesting research topics in food technology.

Marked increase in tumor transfection with a truncated branched polymer

BACKGROUND

We previously determined that polyplexes formed by linear H2K peptides were more effective in transfecting tumors in vivo than polyplexes formed by branched H2K4b-20 peptides. Based on trypsin digest and salt displacement studies, the linear H2K polyplexes were less stable than the branched H2K4b-20 polyplexes. Because binding and release of the polymer and DNA from the H2K4b-20 polyplex may account for the ineffectiveness, we investigated whether four-branched histidine-lysine (HK) peptides with varying numbers of amino acids in their branches would be more effective in their ability to increase gene expression in tumors in vivo.

METHODS

Linear and branched peptides with multiple -KHHK- motifs were synthesized by solid-phase synthesis. The branched H2K4b-20, -18, -14 and 12 peptides had 20, 18, 14 and 12 amino acids in their branches, respectively. These peptides were examined for their ability to carry luciferase-expressing plasmids to human breast cancer xenografts in a mouse model. With gel retardation and in vivo transfection, the incorporation of a targeting ligand and an endosomal lysis peptide into these polyplexes was also examined. A blocking antibody was pre-injected prior to the polyplexes to determine the role of neuropilin 1 in the uptake of these polyplexes by the tumor. The size of the polyplexes was measured by dynamic light scattering.

RESULTS

Of the four negative surface-charge polyplexes formed by the branched carriers, the H2K4b-14 polyplex was determined to be the most effective plasmid delivery platform to tumors. The incorporation of a targeting ligand and an endosomal lysis peptide into H2K4b-14 polyplexes further enhanced their ability to transfect tumors in vivo. Furthermore, after pre-injecting tumor-bearing mice with a blocking antibody to the neuropilin-1 receptor (NRP-1), there was a marked reduction of tumor gene expression with the modified H2K4b-14 polyplexes, suggesting that NRP-1 mediated their transport into the tumor.

CONCLUSIONS

The present study established that branched peptides intermediate in length were very efficient in delivering plasmids to tumors in vivo.

Peptide-Conjugated Nano Delivery Systems for Therapy and Diagnosis of Cancer

Peptides are strings of approximately 2-50 amino acids, which have gained huge attention for theranostic applications in cancer research due to their various advantages including better biosafety, customizability, convenient process of synthesis, targeting ability via recognizing biological receptors on cancer cells, and better ability to penetrate cell membranes. The conjugation of peptides to the various nano delivery systems (NDS) has been found to provide an added benefit toward targeted delivery for cancer therapy. Moreover, the simultaneous delivery of peptide-conjugated NDS and nano probes has shown potential for the diagnosis of the malignant progression of cancer. In this review, various barriers hindering the targeting capacity of NDS are addressed, and various approaches for conjugating peptides and NDS have been discussed. Moreover, major peptide-based functionalized NDS targeting cancer-specific receptors have been considered, including the conjugation of peptides with extracellular vesicles, which are biological nanovesicles with promising ability for therapy and the diagnosis of cancer.

An update on actively targeted liposomes in advanced drug delivery to glioma

High-grade glioma is one of the most aggressive types of cancer with a low survival rate ranging from 12 to 15 months after the first diagnosis. Though being the most common strategy for glioma therapy, conventional chemotherapy suffers providing the therapeutic dosage of common therapeutics mostly because of limited permeability of blood-brain barrier (BBB), and blood-brain tumor barrier (BBTB) to anticancer agents. Among various nanoformulations, liposomes are considered as the most popular carriers aimed for glioma therapy. However, non-targeted liposomes which passively accumulate in most of the cancer tissues mainly through the enhanced permeation and retention effect (EPR), may not be applicable for glioma therapy due to BBB tight junctions. In the recent decade, the surface modification of liposomes with different active targeting ligands has shown promising results by getting different chemotherapeutics across the BBB and BBTB and leading them into the glioma cells. The present review discusses the major barriers for drug delivery systems to glioma, elaborates the existing mechanisms for liposomes to traverse across the BBB, and explores the main strategies for incorporation of targeting ligands onto the liposomes. It subsequently investigates the most recent and relevant studies of actively targeted liposomes modified with antibodies, aptamers, monosaccharides, polysaccharides, proteins, and peptides applied for effective glioma therapy, and highlights the common challenges facing this area. Finally, the actively targeted liposomes undergoing preclinical and clinical studies for delivery of different anticancer agents to glioma cells will be reviewed.

Macropinocytosis as a cell entry route for peptide-functionalized and bystander nanoparticles

Endocytic pathways provide the primary route for therapeutic and diagnostic nanoparticles (NPs) to enter cells and subcellular compartments. A better understanding of these cell entry processes will not only aid in nanomaterial applications but also broaden our knowledge of cell biology. Among the endocytic routes, macropinocytosis has unique characteristics for engulfing NPs and other large cargo, yet its molecular machinery and involvement in NP uptake are far less characterized relative to other pathways. In this review, we summarize the current knowledge on the macropinocytic machinery, and its involvement in NP internalization. Particularly, we differentiate ligand (specifically peptide)-functionalized and unfunctionalized NPs (bystander NPs). While most of previous research focused on ligand-functionalized NPs, we showcase here a synergistic effect between these two NP types during their cell entry through receptor-mediated macropinocytosis. The regulation of NP uptake efficiency by extracellular amino acids is also highlighted in the context of interconnections between macropinocytosis and metabolic signaling. These discussions may fuel future research interests in improving NP internalization through this pathway, and open a new avenue to study the interplay among endocytosis, metabolism and nanomedicine.

Lactoferrin coated or conjugated nanomaterials as an active targeting approach in nanomedicine

A successful drug delivery to a specific site relies on two essential factors including; efficient entrapment of the drug within the carrier and successful delivery of drug- loaded nanocarrier to the target site without opsonisation or drug release in the circulation before reaching the organ of interest. Lactoferrin (LF) is a glycoprotein belonging to the transferrin (TF) family which can bind to TF receptors (TFRs) and LF membrane internalization receptors (LFRs) highly expressed on the cell surface of both highly proliferating cancer cells and blood brain barrier (BBB), which in turn can facilitate its accessibility to the cell nucleus. This merit could be exploited to develop actively targeted drug delivery systems that can easily cross the BBB or internalize into tumor cells. In this review, the most recent advances of utilizing LF as an active targeting ligand for different types of nanocarriers including: inorganic nanoparticles, dendrimers, synthetic biodegradable polymers, lipid nanocarriers, natural polymers, and nanoemulstions will be highlighted. Collectively, LF seems to be a promising targeting ligand in the field of nanomedicine.

Lactoferrin, a multi-functional glycoprotein: Active therapeutic, drug nanocarrier & targeting ligand

Recent progress in protein-based nanomedicine, inspired by the success of Abraxane® albumin-paclitaxel nanoparticles, have resulted in novel therapeutics used for treatment of challenging diseases like cancer and viral infections. However, absence of specific drug targeting, poor pharmacokinetics, premature drug release, and off-target toxicity are still formidable challenges in the clinic. Therefore, alternative protein-based nanomedicines were developed to overcome those challenges. In this regard, lactoferrin (Lf), a glycoprotein of transferrin family, offers a promising biodegradable well tolerated material that could be exploited both as an active therapeutic and drug nanocarrier. This review highlights the major pharmacological actions of Lf including anti-cancer, antiviral, and immunomodulatory actions. Delivery technologies of Lf to improve its pries and enhance its efficacy were also reviewed. Moreover, different nano-engineering strategies used for fabrication of drug-loaded Lf nanocarriers were discussed. In addition, the use of Lf for functionalization of drug nanocarriers with emphasis on tumor-targeted drug delivery was illustrated. Besides its wide application in oncology nano-therapeutics, we discussed the recent advances of Lf-based nanocarriers as efficient platforms for delivery of anti-parkinsonian, anti-Alzheimer, anti-viral drugs, immunomodulatory and bone engineering applications.

Overcoming the blood-brain barrier in neurodegenerative disorders and brain tumours

Drug delivery is one of the major challenges in the treatment of central nervous system disorders. The brain needs to be protected from harmful agents, which are done by the capillary network, the so-called blood-brain barrier (BBB). This protective guard also prevents the delivery of therapeutic agents to the brain and limits the effectiveness of treatment. For this reason, various strategies have been explored by scientists for overcoming the BBB from disruption of the BBB to targeted delivery of nanoparticles (NPs) and cells and immunotherapy. In this review, different promising brain drug delivery strategies including disruption of tight junctions in the BBB, enhanced transcellular transport by peptide-based delivery, local delivery strategies, NP delivery, and cell-based delivery have been fully discussed.

Overcoming the Blood-Brain Barrier: Successes and Challenges in Developing Nanoparticle-Mediated Drug Delivery Systems for the Treatment of Brain Tumours

High-grade gliomas are still characterized by a poor prognosis, despite recent advances in surgical treatment. Chemotherapy is currently practiced after surgery, but its efficacy is limited by aspecific toxicity on healthy cells, tumour cell chemoresistance, poor selectivity, and especially by the blood–brain barrier (BBB). Thus, despite the large number of potential drug candidates, the choice of effective chemotherapeutics is still limited to few compounds. Malignant gliomas are characterized by high infiltration and neovascularization, and leaky BBB (the so-called blood–brain tumour barrier); surgical resection is often incomplete, leaving residual cells that are able to migrate and proliferate. Nanocarriers can favour delivery of chemotherapeutics to brain tumours owing to different strategies, including chemical stabilization of the drug in the bloodstream; passive targeting (because of the leaky vascularization at the tumour site); inhibition of drug efflux mechanisms in endothelial and cancer cells; and active targeting by exploiting carriers and receptors overexpressed at the blood–brain tumour barrier. Within this concern, a suitable nanomedicine-based therapy for gliomas should not be limited to cytotoxic agents, but also target the most important pathogenetic mechanisms, including cell differentiation pathways and angiogenesis. Moreover, the combinatorial approach of cell therapy plus nanomedicine strategies can open new therapeutical opportunities. The major part of attempted preclinical approaches on animal models involves active targeting with protein ligands, but, despite encouraging results, a few number of nanomedicines reached clinical trials, and most of them include drug-loaded nanocarriers free of targeting ligands, also because of safety and scalability concerns.

3D cultures for modeling nanomaterial-based photothermal therapy

Photothermal therapy (PTT) is one of the most promising techniques for cancer tumor ablation. Nanoparticles are increasingly being investigated for use with PTT and can serve as theranostic agents. Based on the ability of near-infrared nano-photo-absorbers to generate heat under laser irradiation, PTT could prove advantageous in certain situations over more classical cancer therapies. To analyze the efficacy of nanoparticle-based PTT, preclinical in vitro studies typically use 2D cultures, but this method cannot completely mimic the complex tumor organization, bioactivity, and physiology that all control the complex penetration depth, biodistribution, and tissue diffusion parameters of nanomaterials in vivo. To fill this knowledge gap, 3D culture systems have been explored for PTT analysis. These models provide more realistic microenvironments that allow spatiotemporal oxygen gradients and cancer cell adaptations to be considered. This review highlights the work that has been done to advance 3D models for cancer microenvironment modeling, specifically in the context of advanced, functionalized nanoparticle-directed PTT.

Fe3+-Coordinated Multifunctional Elastic Nanoplatform for Effective in Vivo Gene Transfection

The common phenomenon that the nonviral vectors have much lower transfection efficiency in vivo than in vitro greatly restricts their further developments and applications. Possible reasons are lacking targeting ability, elimination by the reticuloendothelial system (RES), and insufficient nuclear transport. Here, a novel, flexible, and deformable polymer Fe@PEI-R12 (tLyp-1-NLS) is reported for shortening the gap between in vitro and in vivo gene transfection efficiency. The amorphous network structure Fe@PEI with deformation ability acquired by coordination cross-linking of Fe³⁺ and low-molecular-weight polyethylenimine (LMW-PEI) constructs the core and serves as the gene reservoir, and it can squeeze out through RES filter holes when trapped in the spleen. The bifunctional peptide R12 provided tumor targeting and enhanced nuclear delivery ability. Additionally, the Fe³⁺ from Fe@PEI-R12 could trigger endogenous hydrogen peroxide (H₂O₂) decomposition to produce O₂, thereby reducing the adverse effects of tumor hypoxia. It is demonstrated that the Fe@PEI-R12/pDNA complexes could pass through membrane filters, subsequently achieving long circulation time, and Fe@PEI-R12 had a tendency to accumulate in tumor tissue and mediate pGL3-control expression. Therefore, the multifunctional nanoplatform has the potential for effective in vivo gene delivery.

Characterization and targeting ability evaluation of cell-penetrating peptide LyP-1 modified alginate-based nanoparticles

Doxorubicin hydrochloride (DOX) shows a powerful treatment effect on breast cancer. However, for its indiscriminate distribution after systemic administration, the therapeutic response of DOX will reduce and even result in serious adverse reactions during the long-term administration. To achieve better treatment, in this study we established a non-condensing sodium alginate-based nanoparticle-encapsulated DOX (DOX/NP), the surface of which was modified with cell-penetrating peptide LyP-1 (namely LyP-1-DOX/NP) to attain active targeting towards breast cancer cells. The size of LyP-1-DOX/NP was 138.50 ± 4.65 nm, with a polydispersity index (PDI) of 0.22 ± 0.02, and the zeta potential was 18.60 ± 0.49 mV. The drug loading efficiency (DLE) for the preparation was 91.21 ± 2.01%, with an encapsulation efficiency (EE) of 12.37 ± 0.35%. The nanoparticles exhibited good stability in vitro and slower release trend compared with free DOX in PBS at pH7.4. In vitro cytopharmacodynamics showed that LyP-1-DOX/NP had an excellent anti-breast cancer effect against MDA-MB-231 cells by the MTT test. The uptake amount of LyP-1-DOX/NP by MDA-MB-231 cells was much higher than that of free DOX or unmodified DOX/NP at all time points. Further in vivo pharmacokinetics studies showed that the concentration of LyP-1-DOX/NP was higher than that of free DOX or DOX/NP both in plasma and in tumor, suggesting its favorable long circulation and enhancing targeting property. The present study provides a promising strategy for using the LyP-1 cell-penetrating peptide to modify nanoparticles for enhancing their targeting ability towards breast cancer.

Doxorubicin hydrochloride (DOX) shows a powerful treatment effect on breast cancer.

A new molecular probe: An NRP-1 targeting probe for the grading diagnosis of glioma in nude mice

Magnetic resonance molecular imaging, as a safe imaging technology, provides a new idea for the early qualitative and hierarchical diagnosis of gliomas. The purpose of this study was to design and evaluate the value of neuropilin-1 (NRP-1) targeting molecular probes in the hierarchical diagnosis of gliomas. First, we created an NRP-1 targeted magnetic resonance molecular probe (USPIO-PEG-tLyP-1) by combining the polypeptide tLyP-1 with ultra-small superparamagnetic iron oxide nanoparticles (USPIONs), detecting the physical properties by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Second, in vivo experiments, we established two different degrees of malignant gliomas in-situ in nude mice by injecting U87 and CHG-5 cells. Then, to detect the binding ability of the probe with different grades of tumour tissues, we injected the probe into the tumour-bearing mice through the tail vein. Next, MRI was performed before injection, and 6 h, 12 h, 24 h after injection, and we found significantly more iron particles in the tumour tissues of U87 tumour-bearing mice than in tumour tissues of CHG-5 tumour-bearing mice. The signal intensities of the T2-weighted images of the tumour tissues of each group as well as microscopic observations by Prussian blue staining indicated that the binding ability of this molecular probe to U87 glioma (HGG) with high NRP-1 expression was significantly greater than that of CHG-5 glioma (LGG) with low NRP-1 expression (P < 0.01). Therefore, this study confirms that the novel molecular probe USPIO-PEG-tLyP-1 can be used for the grading diagnosis by MRI for gliomas of high and low grade with different NRP-1 expression levels.

Ultrasmall Core-Shell Silica Nanoparticles for Precision Drug Delivery in a High-Grade Malignant Brain Tumor Model

PURPOSE

Small-molecule inhibitors have revolutionized treatment of certain genomically defined solid cancers. Despite breakthroughs in treating systemic disease, central nervous system (CNS) metastatic progression is common, and advancements in treating CNS malignancies remain sparse. By improving drug penetration across a variably permeable blood-brain barrier and diffusion across intratumoral compartments, more uniform delivery and distribution can be achieved to enhance efficacy.

EXPERIMENTAL DESIGN

Ultrasmall fluorescent core-shell silica nanoparticles, Cornell prime dots (C' dots), were functionalized with α_v integrin-binding (cRGD), or nontargeting (cRAD) peptides, and PET labels (¹²⁴I, ⁸⁹Zr) to investigate the utility of dual-modality cRGD-C' dots for enhancing accumulation, distribution, and retention (ADR) in a genetically engineered mouse model of glioblastoma (mGBM). mGBMs were systemically treated with ¹²⁴I-cRGD- or ¹²⁴I-cRAD-C' dots and sacrificed at 3 and 96 hours, with concurrent intravital injections of FITC-dextran for mapping blood-brain barrier breakdown and the nuclear stain Hoechst. We further assessed target inhibition and ADR following attachment of dasatinib, creating nanoparticle-drug conjugates (Das-NDCs). Imaging findings were confirmed with ex vivo autoradiography, fluorescence microscopy, and p-S6RP IHC.

RESULTS

Improvements in brain tumor delivery and penetration, as well as enhancement in the ADR, were observed following administration of integrin-targeted C' dots, as compared with a nontargeted control. Furthermore, attachment of the small-molecule inhibitor, dasatinib, led to its successful drug delivery throughout mGBM, demonstrated by downstream pathway inhibition.

CONCLUSIONS

These results demonstrate that highly engineered C' dots are promising drug delivery vehicles capable of navigating the complex physiologic barriers observed in a clinically relevant brain tumor model.

Efficacy of a novel LyP-1-containing self-microemulsifying drug delivery system (SMEDDS) for active targeting to breast cancer

An ideal cancer therapy targets the tumor cells selectively without damaging healthy tissues. Even though the tumor-specific markers are limited, these molecules can be used for the delivery of anti-cancer drugs as an active targeting strategy. Since the lymphatic system plays a critical role in the dissemination of cancer cells, the drugs directed through lymphatics can feasibly reach to the sites of metastasis. LyP-1 is a peptide that binds to the p32 receptor which is highly expressed not only on the lymphatic endothelium but also on the malignant cells; thus, making this peptide ligand a preferable candidate to mediate active targeting of lymphatics and cancer cells. In this study, different formulations of LyP-1 containing lipid-based nanopharmaceutics so-called self-microemulsifying drug delivery systems (SMEDDS) were developed and tested for their efficacy in targeting breast cancer. Following the selection of non-toxic formulation, doxorubicin hydrochloride and LyP-1 were co-administered in the SMEDDS, which resulted in a significant increase in in vitro cytotoxicity in p32-expressing breast cancer cells, 4T1 and MDA-MB-231. Accordingly, the uptake of LyP-1 in the SMEDDS by the cancer cells was demonstrated. The expression of p32 was detected in the 4T1 tumor tissues which were efficiently targeted with LyP-1 in the SMEDDS. When doxorubicin was co-administrated with LyP-1 in SMEDDS via intraperitonial administration, tumor growth and metastasis were significantly reduced. In conclusion, a novel and efficacious SMEDDS formulation containing LyP-1 with a droplet size less than 100 nm was developed for the lymphatic targeting of breast cancer.

Functional Nanoparticles for Tumor Penetration of Therapeutics

Theranostic nanoparticles recently received great interest for uniting unique functions to amplify therapeutic efficacy and reduce side effects. Despite the enhanced permeability and retention (EPR) effect, which amplifies the accumulation of nanoparticles at the site of a tumor, tumor heterogeneity caused by the dense extracellular matrix of growing cancer cells and the interstitial fluid pressure from abnormal angiogenesis in the tumor inhibit drug/particle penetration, leading to inhomogeneous and limited treatments. Therefore, nanoparticles for penetrated delivery should be designed with different strategies to enhance efficacy. Many strategies were developed to overcome the obstacles in cancer therapy, and they can be divided into three main parts: size changeability, ligand functionalization, and modulation of the tumor microenvironment. This review summarizes the results of ameliorated tumor penetration approaches and amplified therapeutic efficacy in nanomedicines. As the references reveal, further study needs to be conducted with comprehensive strategies with broad applicability and potential translational development.

Lactoferrin- and RGD-comodified, temozolomide and vincristine-coloaded nanostructured lipid carriers for gliomatosis cerebri combination therapy

PURPOSE

Glioblastoma multiforme (GBM) is the most common malignant brain tumor originating in the central nervous system in adults. Based on nanotechnology such as liposomes, polymeric nanoparticles, and lipid nanoparticles, recent research efforts have been aimed to target drugs to the brain.

METHODS

In this study, lactoferrin- and arginine-glycine-aspartic acid (RGD) dual- ligand-comodified, temozolomide and vincristine-coloaded nanostructured lipid carriers (L/RT/V-NLCs) were introduced for GBM combination therapy. The physicochemical properties of L/R-T/V-NLCs such as particle size, zeta potential, and encapsulated efficiency are measured. The drug release profile, cellular uptake, cytotoxicity, tissue distribution, and antitumor activity of L/R-T/V-NLCs are further investigated in vitro and in vivo.

RESULTS

L/R-T/V-NLCs were stable with nanosize and high drug encapsulation efficiency. L/R-T/V-NLCs exhibited sustained-release behavior, high cellular uptake, high cytotoxicity and synergy effects, increased drug accumulation in the tumor tissue, and obvious tumor inhibition efficiency with low systemic toxicity.

CONCLUSION

L/R-T/V-NLCs could be a promising drug delivery system for glioblastoma chemotherapy.

Multicellular Tumor Spheroids (MCTS) as a 3D In Vitro Evaluation Tool of Nanoparticles

Multicellular tumor spheroid models (MCTS) are often coined as 3D in vitro models that can mimic the microenvironment of tissues. MCTS have gained increasing interest in the nano-biotechnology field as they can provide easily accessible information on the performance of nanoparticles without using animal models. Considering that many countries have put restrictions on animals testing, which will only tighten in the future as seen by the recent developments in the Netherlands, 3D models will become an even more valuable tool. Here, an overview on MCTS is provided, focusing on their use in cancer research as most nanoparticles are tested in MCTS for treatment of primary tumors. Thereafter, various types of nanoparticles-from self-assembled block copolymers to inorganic nanoparticles, are discussed. A range of physicochemical parameters including the size, shape, surface chemistry, ligands attachment, stability, and stiffness are found to influence nanoparticles in MCTS. Some of these studies are complemented by animal studies confirming that lessons from MCTS can in part predict the behaviour in vivo. In summary, MCTS are suitable models to gain additional information on nanoparticles. While not being able to replace in vivo studies, they can bridge the gap between traditional 2D in vitro studies and in vivo models.

Tumor target amplification: Implications for nano drug delivery systems

Tumor cells overexpress surface markers which are absent from normal cells. These tumor-restricted antigenic signatures are a fundamental basis for distinguishing on-target from off-target cells for ligand-directed targeting of cancer cells. Unfortunately, tumor heterogeneity impedes the establishment of a solid expression pattern for a given target marker, leading to drastic changes in quality (availability) and quantity (number) of the target. Consequently, a subset of cancer cells remains untargeted during the course of treatment, which subsequently promotes drug-resistance and cancer relapse. Since target inefficiency is only problematic for cancer treatment and not for treatment of other pathological conditions such as viral/bacterial infections, target amplification or the generation of novel targets is key to providing eligible antigenic markers for effective targeted therapy. This review summarizes the limitations of current ligand-directed targeting strategies and provides a comprehensive overview of tumor target amplification strategies, including self-amplifying systems, dual targeting, artificial markers and peptide modification. We also discuss the therapeutic and diagnostic potential of these approaches, the underlying mechanism(s) and established methodologies, mostly in the context of different nanodelivery systems, to facilitate more effective ligand-directed cancer cell monitoring and targeting.

Facile construction of dual-targeting delivery system by using lipid capped polymer nanoparticles for anti-glioma therapy

A facile and reliable platform to construct dual targeting nanoparticles for glioma treatment, and the targeting efficiency was demonstrated.

Targeted Delivery of siRNA Therapeutics to Malignant Tumors

Over the past 20 years, a diverse group of ligands targeting surface biomarkers or receptors has been identified with several investigated to target siRNA to tumors. Many approaches to developing tumor-homing peptides, RNA and DNA aptamers, and single-chain variable fragment antibodies by using phage display, in vitro evolution, and recombinant antibody methods could not have been imagined by researchers in the 1980s. Despite these many scientific advances, there is no reason to expect that the ligand field will not continue to evolve. From development of ligands based on novel or existing biomarkers to linking ligands to drugs and gene and antisense delivery systems, several fields have coalesced to facilitate ligand-directed siRNA therapeutics. In this review, we discuss the major categories of ligand-targeted siRNA therapeutics for tumors, as well as the different strategies to identify new ligands.

VEGF-mediated tight junctions pathological fenestration enhances doxorubicin-loaded glycolipid-like nanoparticles traversing BBB for glioblastoma-targeting therapy

The existence of blood-brain barrier (BBB) greatly hindered the penetration and accumulation of chemotherapeutics into glioblastoma (GBM), accompany with poor therapeutic effects. The growth of GBM supervene the impairment of tight junctions (TJs); however, the pathogenesis of BBB breakdown in GBM is essentially poorly understood. This study found that vascular endothelial growth factor (VEGF) secreted by GBM cells plays an important role in increasing the permeability of BBB by disrupting endothelial tight junction proteins claudin-5 and thus gave doxorubicin (DOX)-loaded glycolipid-like nanoparticles (Ap-CSSA/DOX), an effective entrance to brain tumor region for GBM-targeting therapy. In addition, VEGF downregulates the expression of claudin-5 with a dose-dependent mode, and interfering with the VEGF/VEGFR pathway using its inhibitor axitinib could reduce the permeability of BBB and enhance the integrity of the barrier. Ap-CSSA/DOX nanoparticles showed high affinity to expressed low-density lipoprotein receptor-related proteins 1 (LRP1) in both BBB and GBM. And BBB pathological fenestration in GBM further exposed more LRP1 binding sites for Ap-CSSA/DOX nanoparticles targeting to brain tumor, resulting in a higher transmembrane transport ratio in vitro and a stronger brain tumor biodistribution in vivo, and finally realizing a considerable antitumor effect. Overall, taking advantage of BBB pathological features to design an appropriate nanodrug delivery system (NDDS) might provide new insights into other central nervous system (CNS) diseases treatment.

A hindsight reflection on the clinical studies of poly(l-glutamic acid)-paclitaxel

Chemotherapy for cancer treatment is limited by the excessive toxicity to normal tissues. The design of chemodrug-loaded nanoformulations provides a unique approach to improve the treatment efficacy while minimizing toxicity. Despite the numerous publications of nanomedicine for the last several decades, however, only a small fraction of the developed nanoformulations have entered clinical trials, with even fewer being approved for clinical application. Poly(l-glutamic acid)-paclitaxel (PG-TXL) belongs to the few formulations that reached phase III clinical trials. Unfortunately, the development of PG-TXL stopped in 2016 due to the inability to show significant improvement over current standard care. This review will provide an overview of the preclinical and clinical evaluations of PG-TXL, and discuss lessons to be learned from this ordeal. The precise identification of suitable patients for clinical trial studies, deep understanding of the mechanisms of action, and an effective academic-industry partnership throughout all phases of drug development are important for the successful bench-to-bedside translation of new nanoformulations. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Peptide-Based Structures.

Molecular dynamics, thermodynamic, and mutational binding studies for tumor-specific LyP-1 in complex with p32

Recent studies in tumor homing peptides have shown the specificity of LyP-1 (CGNKRTRGC) to tumor lymphatics. In this present work, we evaluated the possible interactions between cyclic LyP-1 and its receptor, p32, with molecular dynamics and docking studies in order to lead the design of novel LyP-1 derivatives, which could bind to p32 more effectively and perform enhanced antitumor effect. The total binding enthalpy energies have been obtained by MM-PBSA thermodynamic computations and the favorability of p32.LyP-1 complex in water has been shown by explicit water MD computations. The last 30 ns of molecular dynamics trajectory have shown the strong interaction of LyP-1 with the inner surface chains of p32, especially with chains B and C. ALA-SCAN mutagenesis studies have indicated the considerable influence of Asn3, Lys4, Arg5, and Arg7 amino acid residues on the specific binding of LyP-1. Within the knowledge of the critical role of p32 receptor in cancer cell metabolism, this study can lead to further developments in anticancer therapy by targeting p32 with LyP-1 derivatives as active targeting moiety. This data can also be applied for the development of new drug delivery systems in which LyP-1 can be used for its targeting and anticancer properties.

Tumor penetrating peptides for improved drug delivery

In vivo screening of phage libraries in tumor-bearing mice has been used to identify peptides that direct phage homing to a tumor. The power of in vivo phage screening is illustrated by the recent discovery of peptides with unique tumor-penetrating properties. These peptides activate an endocytic transport pathway related to but distinct from macropinocytosis. They do so through a complex process that involves binding to a primary, tumor-specific receptor, followed by a proteolytic cleavage, and binding to a second receptor. The second receptor, neuropilin-1 (or neuropilin-2) activates the transport pathway. This trans-tissue pathway, dubbed the C-end Rule (CendR) pathway, mediates the extravasation transport through extravascular tumor tissue of payloads ranging from small molecule drugs to nanoparticles. The CendR technology provides a solution to a major problem in tumor therapy, poor penetration of drugs into tumors. Targeted delivery with tumor-penetrating peptides has been shown to specifically increase the accumulation of drugs, antibodies and nanotherapeutics in experimental tumors in vivo, and in human tumors ex vivo. Remarkably the payload does not have to be coupled to the peptide; the peptide activates a bulk transport system that sweeps along a drug present in the blood. Treatment studies in mice have shown improved anti-tumor efficacy and less damage to normal tissues with drugs ranging from traditional chemotherapeutics to antibodies, and to nanoparticle drugs.

Tumor homing and penetrating peptide-conjugated niosomes as multi-drug carriers for tumor-targeted drug delivery

The development of nanoscale drug delivery systems, which can mediate efficient tumor targeting together with high cellular internalization, is crucial for glioma treatment.

Phenylboronic acid-incorporated elastin-like polypeptide nanoparticle drug delivery systems

Packaging hydrophobic drugs into nanoparticles can improve their aqueous solubility, tumor-specific accumulation and therapeutic effect.

The Penetrated Delivery of Drug and Energy to Tumors by Lipo-Graphene Nanosponges for Photolytic Therapy

Delivery of drug and energy within responsive carriers that effectively target and accumulate in cancer cells promises to mitigate side effects and to enhance the uniquely therapeutic efficacy demanded for personalized medicine. To achieve this goal, however, these carriers, which are usually piled up at the periphery of tumors near the blood vessel, must simultaneously overcome the challenges associated with low tumor penetration and the transport of sufficient cargos to deep tumors to eradicate whole cancer cells. Here, we report a sponge-like carbon material on graphene nanosheet (graphene nanosponge)-supported lipid bilayers (lipo-GNS) that doubles as a photothermal agent and a high cargo payload platform and releases a burst of drug/energy (docetaxel (DTX) and gasified perfluorohexane (PFH)) and intense heat upon near-infrared irradiation. Ultrasmall lipo-GNS (40 nm) modified with a tumor-targeting protein that penetrates tumor spheroids through transcytosis exhibited a 200-fold increase in accumulation relative to a 270 nm variant of the lipo-GNS. Furthermore, a combination of therapeutic agents (DTX and PFH) delivered by lipo-GNS into tumors was gasified and released into tumor spheroids and successfully ruptured and suppressed xenograft tumors in 16 days without distal harm when subjected to a single 10 min near-infrared laser treatment. Moreover, no tumor recurrence was observed over 60 days post-treatment. This sophisticated lipo-GNS is an excellent delivery platform for penetrated, photoresponsive, and combined gasification/chemo-thermotherapy to facilitate tumor treatment and for use in other biological applications.

Tumor-Homing and Penetrating Peptide-Functionalized Photosensitizer-Conjugated PEG-PLA Nanoparticles for Chemo-Photodynamic Combination Therapy of Drug-Resistant Cancer

The combination of photodynamic therapy (PDT) and chemotherapy holds great potential in combating drug-resistant cancers. However, the major challenge that lies ahead is how to achieve high coloading capacity for both photosensitizer and chemo-drugs and how to gain efficient delivery of drugs to the drug-resistant tumors. In this study, we prepared a nanovehicle for codelivery of photosensitizer (pyropheophorbide-a, PPa) and chemo-drugs (paclitaxel, PTX) based on the synthesis of PPa-conjugated amphiphilic copolymer PPa-PLA-PEG-PLA-PPa. The obtained nanoparticles (PP NP) exhibited a satisfactory high drug-loading capacity for both drugs. To achieve effective tumor-targeting therapy, the surface of PP NP was decorated with a tumor-homing and penetrating peptide F3. In vitro cellular experiments showed that F3-functionalized PP NP (F3-PP NP) exhibited higher cellular association than PP NP and resulted in the strongest antiproliferation effect. In addition, compared with the unmodified nanoparticles, F3-PP NP exhibited a more preferential enrichment at the tumor site. Pharmacodynamics evaluation in vivo demonstrated that a longer survival time was achieved by the tumor-bearing mice treated with PP NP (+laser) than those treated with chemotherapy only or PDT only. Such antitumor efficacy of combination therapy was further improved following the F3 peptide functionalization. Collectively, these results suggested that targeted combination therapy may pave a promising way for the therapy of drug-resistant tumor.