Distinct Proteins in Protein Corona of Nanoparticles Represent a Promising Venue for Endogenous Targeting - Part I: In vitro Release and Intracellular Uptake Perspective

Surface-modified cationic liposomes with a matrix metalloproteinase-degradable polyethylene glycol derivative improved doxorubicin delivery in murine colon cancer

PEGylation is a commonly used approach to prolong the blood circulation time of cationic liposomes. However, PEGylation is associated with the "PEG dilemma", which hinders binding and uptake into tumor cells. The cleavable PEG products are a possible solution to this problem. In the current research, doxorubicin-loaded cationic liposomes (Dox-CLs) surface-conjugated with a matrix metalloproteinase-2 (MMP-2)-sensitive octapeptide linker-PEG derivative were prepared and compared to non-PEGylated and PEGylated CLs in terms of size, surface charge, drug encapsulation and release, uptake, in vivo pharmacokinetics, and anticancer efficacy. It was postulated that PEG deshielding in response to the overexpressed MMP-2 in the tumor microenvironment increases the interaction of protected CLs with cellular membranes and improves their uptake by tumor cells/vasculature. MMP2-responsive Dox-CLs had particle sizes of ∼115-140 nm, surface charges of ∼+25 mV, and encapsulation efficiencies of ∼85-95%. In vitro cytotoxicity assessments showed significantly enhanced uptake and cytotoxicity of PEG-cleavable CLs compared to their non-cleavable PEG-coated counterparts or Caelyx®. Also, the chick chorioallantoic membrane assay showed great antiangiogenesis ability of Dox-CLs leading to target and prevent tumor neovascularization. Besides, in vivo studies showed an effective therapeutic efficacy of PEG-cleavable Dox-CLs in murine colorectal cancer with negligible hematological and histopathological toxicity. Altogether, our results showed that MMP2-responsive Dox-CLs could be served as a promising approach to improve tumor drug delivery and uptake.

Macrophage-modulating nanomedicine for cancer immunotherapy

Tumor-associated macrophages (TAMs) play crucial roles in the immunosuppressive solid tumor microenvironment (TME). Despite their tumor-promoting functions, TAMs can also be therapeutically modulated to exhibit tumor-killing properties, making them attractive targets for tumor immunotherapy. This review highlights the recent advances in nanomedicine-based strategies centered around macrophages for enhanced cancer immunotherapy. Emerging nanomedicine-based strategies to modulate TAMs in cancer treatment include repolarization of the TAM phenotype, inhibition of monocyte recruitment, depletion of TAMs, and blockage of immune checkpoints. These strategies have shown great promise in significantly improving the efficacy of cancer immunotherapy. Moreover, macrophage-inspired drug delivery systems have demonstrated significant promise in inducing immunotherapeutic effects and enhancing therapeutic efficacy by facilitating evasion from the reticuloendothelial system and promoting accumulation at the tumor site. Finally, we also discuss the challenges and propose future opportunities associated with macrophage-modulating nanomedicine to enhance cancer immunotherapy.

Multitarget, multiagent PLGA nanoparticles for simultaneous tumor eradication and TME remodeling in a melanoma mouse model

Despite the fact that chemoimmunotherapy has emerged as a key component in the era of cancer immunotherapy, it is challenged by the complex tumor microenvironment (TME) that is jam-packed with cellular and non-cellular immunosuppressive components. The aim of this study was to design a nanoparticulate system capable of sufficiently accumulating in the tumor and spleen to mediate local and systemic immune responses, respectively. The study also aimed to remodel the immunosuppressive TME. For such reasons, multi-functional polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) were engineered to simultaneously eradicate the cancer cells, silence the tumor-associated fibroblasts (TAFs), and re-educate the tumor-associated macrophages (TAMs) using doxorubicin, losartan, and metformin, respectively. These agents were also selected for their ability to tip the balance of the splenic immune cells towards immunostimulatory phenotypes. To establish TAM and TAF cultures, normal macrophages and fibroblasts were incubated with B16F10 melanoma cell (Mel)-derived secretome. Drug-loaded PLGA NPs were prepared, characterized, and tested in the target cell types. Organ distribution of fluorescein-loaded PLGA NPs was evaluated in a mouse model of melanoma. Finally, the local and systemic effects of different combination therapy programs were portrayed. The in vitro studies showed that the drug-loaded PLGA NPs could significantly ablate the immunosuppressive nature of Mel and skew TAMs and TAFs towards more favorable phenotypes. While in vivo, PLGA NPs were proven to exhibit long blood circulation time and to localize preferentially in the tumor and the spleen. The combination of either metformin or losartan with doxorubicin was superior to the monotherapy, both locally and systemically. However, the three-agent combo produced detrimental effects in the form of compromised well-being, immune depletion, and metastasis. These findings indicate the potential of TME remodeling as means to prime the tumors for successful chemoimmunotherapy. In addition, they shed light on the importance of the careful use of combination therapies and the necessity of employing dose-reduction strategies. D-NPs doxorubicin-loaded NPs, M-NPs metformin-loaded NPs, L-NPs losartan-loaded NPs, TAMs tumor-associated macrophages, TAFs tumor-associated fibroblasts, PD-L1 programmed death ligand 1, TNF-α tumor necrosis factor alpha, TGF-β transforming growth factor beta, CD206/40/86 cluster of differentiation 206/40/86, α-SMA alpha-smooth muscle actin, MMPs matrix metalloproteases.

Interaction of Graphene Oxide Particles and Dendrimers with Human Breast Cancer Cells by Real-Time Microscopy

Graphene oxide (GOX) has become attractive due to its unique physicochemical properties. This nanomaterial can associate with other dendrimers, making them more soluble and allowing better interaction with biomacromolecules. The present study aimed to investigate, by real-time microscopy, the behavior of human breast cancer cells exposed to particles of materials based on graphene oxide. The MCF-7 cell line was exposed to GOX, GOX associated with Polypropylenimine hexadecaamine Dendrimer, Generation 3.0-DAB-AM-16 (GOXD) and GOX associated with polypropyleneimine-PAMAM (GOXP) in the presence or absence of fetal bovine serum (FBS). GOX, GOXD and GOXP were taken up by the cells in clusters and then the clusters were fragmented into smaller ones inside the cells. Real-time microscopy showed that the presence of FBS in the culture medium could allow a more efficient internalization of graphene materials. After internalizing the materials, cells can redistribute the clumps to their daughter cells. In conclusion, the present study showed that the particles can adhere to the cell surface, favoring their internalization. The presence of FBS contributed to the formation of smaller aggregates of particles, avoiding the formation of large ones, and thus transmitted a more efficient internalization of the materials through the interaction of the particles with the cell membrane.

Exploiting Nanomedicine for Cancer Polychemotherapy: Recent Advances and Clinical Applications

The most important limitations of chemotherapeutic agents are severe side effects and the development of multi-drug resistance. Recently, the clinical successes achieved with immunotherapy have revolutionized the treatment of several advanced-stage malignancies, but most patients do not respond and many of them develop immune-related adverse events. Loading synergistic combinations of different anti-tumor drugs in nanocarriers may enhance their efficacy and reduce life-threatening toxicities. Thereafter, nanomedicines may synergize with pharmacological, immunological, and physical combined treatments, and should be increasingly integrated in multimodal combination therapy regimens. The goal of this manuscript is to provide better understanding and key considerations for developing new combined nanomedicines and nanotheranostics. We will clarify the potential of combined nanomedicine strategies that are designed to target different steps of the cancer growth as well as its microenvironment and immunity interactions. Moreover, we will describe relevant experiments in animal models and discuss issues raised by translation in the human setting.

Protein corona: Friend or foe? Co-opting serum proteins for nanoparticle delivery

For systemically delivered nanoparticles to reach target tissues, they must first circulate long enough to reach the target and extravasate there. A challenge is that the particles end up engaging with serum proteins and undergo immune cell recognition and premature clearance. The serum protein binding, also known as protein corona formation, is difficult to prevent, even with artificial protection via "stealth" coating. Protein corona may be problematic as it can interfere with the interaction of targeting ligands with tissue-specific receptors and abrogate the so-called active targeting process, hence, the efficiency of drug delivery. However, recent studies show that serum protein binding to circulating nanoparticles may be actively exploited to enhance their downstream delivery. This review summarizes known issues of protein corona and traditional strategies to control the corona, such as avoiding or overriding its formation, as well as emerging efforts to enhance drug delivery to target organs via nanoparticles. It concludes with a discussion of prevailing challenges in exploiting protein corona for nanoparticle development.

Drugless nanoparticles tune-up an array of intertwined pathways contributing to immune checkpoint signaling and metabolic reprogramming in triple-negative breast cancer

Metabolic reprogramming 'Warburg effect' and immune checkpoint signaling are immunosuppressive hallmarks of triple-negative breast cancer (TNBC) contributing to the limited clinical applicability of immunotherapy. Biomaterials arise as novel tools for immunomodulation of the tumor microenvironment that can be used alongside conventional immunotherapeutics. Chitosan and lecithin are examples of versatile biomaterials with interesting immunomodulatory properties. In this study, we aimed at investigation of the role of carefully designed hybrid nanoparticles (NPs) on common mediators of both programmed death ligand 1 (PD-L1) expression and glycolytic metabolism. Hybrid lecithin-chitosan NPs were prepared and characterized. Their intracellular concentration, localization and effect on the viability of MDA-MB-231 cells were assessed. Glycolytic metabolism was quantified by measuring glucose consumption, adenosine triphosphate (ATP) generation, lactate production and extracellular acidification. Nitric oxide production was quantified using Greiss reagent. Gene expression of inducible nitric oxide synthase (iNOS), phosphatidylinositol-3-kinase (PI3K), protein kinase B (PKB or Akt), mammalian target of rapamycin (mTOR), hypoxia-inducible factor 1α(HIF-1α) and PD-L1 was quantified by quantitative reverse transcription polymerase chain reaction (q-RT-PCR). Chitosan, lecithin and the NPs-formulated forms have been shown to influence the 'Warburg effect' and immune checkpoint signaling of TNBC cells differently. The composition of the hybrid systems dictated their subcellular localization and hence the positive or negative impact on the immunosuppressive characteristics of TNBC cells. Carefully engineered hybrid lecithin-chitosan NPs could convert the immune-suppressive microenvironment of TNBC to an immune-active microenvironment via reduction of PD-L1 expression and reversal of the Warburg effect.

Protein adsorption onto nanomaterials engineered for theranostic applications

The key role of biomolecule adsorption onto engineered nanomaterials for therapeutic and diagnostic purposes has been well recognized by the nanobiotechnology community, and our mechanistic understanding of nano-bio interactions has greatly advanced over the past decades. Attention has recently shifted to gaining active control of nano-bio interactions, so as to enhance the efficacy of nanomaterials in biomedical applications. In this review, we summarize progress in this field and outline directions for future development. First, we briefly review fundamental knowledge about the intricate interactions between proteins and nanomaterials, as unraveled by a large number of mechanistic studies. Then, we give a systematic overview of the ways that protein-nanomaterial interactions have been exploited in biomedical applications, including the control of protein adsorption for enhancing the targeting efficiency of nanomedicines, the design of specific protein adsorption layers on the surfaces of nanomaterials for use as drug carriers, and the development of novel nanoparticle array-based sensors based on nano-bio interactions. We will focus on particularly relevant and recent examples within these areas. Finally, we conclude this topical review with an outlook on future developments in this fascinating research field.

The Janus of Protein Corona on nanoparticles for tumor targeting, immunotherapy and diagnosis

The therapeutics based on nanoparticles (NPs) are considered as the promising strategy for tumor detection and treatment. However, one of the most challenges is the adsorption of biomolecules on NPs after their exposition to biological medium, leading unpredictable in vivo behaviors. The interactions caused by protein corona (PC) will influence the biological fate of NPs in either negative or positive ways, including (i) blood circulation, accumulation and penetration of NPs at targeting sites, and further cellular uptake in tumor targeting delivery; (ii) interactions between NPs and receptors on immune cells for immunotherapy. Besides, PC on NPs could be utilized as new biomarker in tumor diagnosis by identifying the minor change of protein concentration led by tumor growth and invasion in blood. Herein, the mechanisms of these PC-mediated effects will be introduced. Moreover, the recent advances about the strategies will be reviewed to reduce negative effects caused by PC and/or utilize positive effects of PC on tumor targeting, immunotherapy and diagnosis, aiming to provide a reasonable perspective to recognize PC with their applications.

Nanoparticles for Cancer Therapy: Current Progress and Challenges

Cancer is one of the leading causes of death and morbidity with a complex pathophysiology. Traditional cancer therapies include chemotherapy, radiation therapy, targeted therapy, and immunotherapy. However, limitations such as lack of specificity, cytotoxicity, and multi-drug resistance pose a substantial challenge for favorable cancer treatment. The advent of nanotechnology has revolutionized the arena of cancer diagnosis and treatment. Nanoparticles (1-100 nm) can be used to treat cancer due to their specific advantages such as biocompatibility, reduced toxicity, more excellent stability, enhanced permeability and retention effect, and precise targeting. Nanoparticles are classified into several main categories. The nanoparticle drug delivery system is particular and utilizes tumor and tumor environment characteristics. Nanoparticles not only solve the limitations of conventional cancer treatment but also overcome multidrug resistance. Additionally, as new multidrug resistance mechanisms are unraveled and studied, nanoparticles are being investigated more vigorously. Various therapeutic implications of nanoformulations have created brand new perspectives for cancer treatment. However, most of the research is limited to in vivo and in vitro studies, and the number of approved nanodrugs has not much amplified over the years. This review discusses numerous types of nanoparticles, targeting mechanisms, and approved nanotherapeutics for oncological implications in cancer treatment. Further, we also summarize the current perspective, advantages, and challenges in clinical translation.

Impact of Protein Corona on the Biological Identity of Nanomedicine: Understanding the Fate of Nanomaterials in the Biological Milieu

Nanoparticles (NPs) in contact with a biological medium are rapidly comprehended by a number of protein molecules resulting in the formation of an NP-protein complex called protein corona (PC). The cell sees the protein-coated NPs as the synthetic identity is masked by protein surfacing. The PC formation ultimately has a substantial impact on various biological processes including drug release, drug targeting, cell recognition, biodistribution, cellular uptake, and therapeutic efficacy. Further, the composition of PC is largely influenced by the physico-chemical properties of NPs viz. the size, shape, surface charge, and surface chemistry in the biological milieu. However, the change in the biological responses of the new substrate depends on the quantity of protein access by the NPs. The PC-layered NPs act as new biological entities and are recognized as different targeting agents for the receptor-mediated ingress of therapeutics in the biological cells. The corona-enveloped NPs have both pros and cons in the biological system. The review provides a brief insight into the impact of biomolecules on nanomaterials carrying cargos and their ultimate fate in the biological milieu.

Green Synthesized Honokiol Transfersomes Relieve the Immunosuppressive and Stem-Like Cell Characteristics of the Aggressive B16F10 Melanoma

BACKGROUND

Honokiol (HK) is a natural bioactive compound with proven antineoplastic properties against melanoma. However, it shows very low bioavailability when administered orally. Alternatively, topical administration may offer a promising route. The objective of the current study was to fabricate HK transfersomes (HKTs) for topical treatment of melanoma. As an ultradeformable carrier system, transfersomes can overcome the physiological barriers to topical treatment of melanoma: the stratum corneum and the anomalous tumor microenvironment. Moreover, the immunomodulatory and stemness-regulation roles of HKTs were the main interest of this study.

METHODS

TFs were prepared using the modified scalable heating method. A three-factor, three-level Box-Behnken design was utilized for the optimization of the process and formulation variables. Intracellular uptake and cytotoxicity of HKTs were evaluated in nonactivated and stromal cell-activated B16F10 melanoma cells to investigate the influence of the complex tumor microenvironment on the efficacy of HK. Finally, ELISA and Western blot were performed to evaluate the expression levels of TGF-β and clusters of differentiation (CD47 and CD133, respectively).

RESULTS

The optimized formula exhibited a mean size of 190 nm, highly negative surface charge, high entrapment efficiency, and sustained release profile. HKTs showed potential to alleviate the immunosuppressive characteristics of B16F10 melanoma in vitro via downregulation of TGF-β signaling. In addition, HKTs reduced expression of the "do not eat me" signal - CD47. Moreover, HKTs possessed additional interesting potential to reduce the expression of the stem-like cell marker CD133. These outcomes were boosted upon combination with metformin, an antihyperglycemic drug recently reported to possess different functions in cancer, while combination with collagenase, an extracellular matrix-depleting enzyme, produced detrimental effects.

CONCLUSION

HKTs represent a promising scalable formulation for treatment of the aggressive B16F10 melanoma, which is jam-packed with immunosuppressive and stem-like cell markers.

Nanomaterials for cancer therapy: current progress and perspectives

Cancer is a disease with complex pathological process. Current chemotherapy faces problems such as lack of specificity, cytotoxicity, induction of multi-drug resistance and stem-like cells growth. Nanomaterials are materials in the nanorange 1–100 nm which possess unique optical, magnetic, and electrical properties. Nanomaterials used in cancer therapy can be classified into several main categories. Targeting cancer cells, tumor microenvironment, and immune system, these nanomaterials have been modified for a wide range of cancer therapies to overcome toxicity and lack of specificity, enhance drug capacity as well as bioavailability. Although the number of studies has been increasing, the number of approved nano-drugs has not increased much over the years. To better improve clinical translation, further research is needed for targeted drug delivery by nano-carriers to reduce toxicity, enhance permeability and retention effects, and minimize the shielding effect of protein corona. This review summarizes novel nanomaterials fabricated in research and clinical use, discusses current limitations and obstacles that hinder the translation from research to clinical use, and provides suggestions for more efficient adoption of nanomaterials in cancer therapy.

Distinct Proteins in Protein Corona of Nanoparticles Represent a Promising Venue for Endogenous Targeting - Part II: In vitro and in vivo Kinetics Study

Introduction

Nanoparticles (NPs), upon introduction to the biological systems, become wrapped by serum and cellular proteins constituting the protein corona (PC). This PC contributes largely to the NPs’ interaction with the biological systems and their subsequent functions. On the one hand, PC can decrease the efficiency of targeting by directing the NPs to the reticuloendothelial system (RES) or by masking the active targeting moieties and decreasing their ability to bind to their target receptors. On the other hand, some components of PC have offered hopes for achieving endogenous targeting.

Methods

In this study, we aimed at the investigation of the role of the PC in determining the behavior of cRGDyk peptide-unconjugated and -conjugated NPs (uNPs and cNPs) exhibiting different physicochemical properties and their interaction with melanoma on in vitro and in vivo levels. Mathematical modeling has been utilized to understand the kinetics of the interaction of NPs with the tumor cells and different organs, respectively.

Results

Endocytosis and exocytosis were reported to occur simultaneously for the utilized NPs. The balance was largely dependent on the NPs’ physicochemical properties and the role of the PC. In addition, distinct proteins present in the PC (illustrated in the results of the PC analysis in part I) have also determined the patterns of the NPs’ distribution in different organs and tissues of the vascular system, the RES system and the target tumot tissue. Vitronectin (VN) was found to mediate higher accumulation in integrin receptor-expressing melanoma cells, while complement 3 protein (C3) and clusterin (CLU), as an opsonin and dysopsonin, respectively, regulated the balance between the RES uptake and blood circulation.

Discussion

PC, if properly modulated by tuning NPs’ physicochemical properties, can serve as a potential venue for optimum utilization of NPs in cancer therapy.