In vivo photothermal treatment by the peritumoral injection of macrophages loaded with gold nanoshells

Biomimetic Systems Involving Macrophages and Their Potential for Targeted Drug Delivery

The concept of targeted drug delivery can be described in terms of the drug systems' ability to mimic the biological objects' property to localize to target cells or tissues. For example, drug delivery systems based on red blood cells or mimicking some of their useful features, such as long circulation in stealth mode, have been known for decades. On the contrary, therapeutic strategies based on macrophages have gained very limited attention until recently. Here, we review two biomimetic strategies associated with macrophages that can be used to develop new therapeutic modalities: first, the mimicry of certain types of macrophages (i.e., the use of macrophages, including tumor-associated or macrophage-derived particles as a carrier for the targeted delivery of therapeutic agents); second, the mimicry of ligands, naturally absorbed by macrophages (i.e., the use of therapeutic agents specifically targeted at macrophages). We discuss the potential applications of biomimetic systems involving macrophages for new advancements in the treatment of infections, inflammatory diseases, and cancer.

In Silico, Combined Plasmonic Photothermal and Photodynamic Therapy in Mice

Plasmonic photothermal and photodynamic therapy (PPTT and PDT, respectively) are two cancer treatments that have the potential to be combined in a synergistic scheme. The aim of this study is to optimize the PPTT treatment part, in order to account for the PDT lack of coverage in the hypoxic tumor volume and in cancer areas laying in deep sites. For the needs of this study, a mouse was modeled, subjected to PDT and its necrotic area was estimated by using the MATLAB software. The same procedure was repeated for PPTT, using COMSOL Multiphysics. PPTT treatment parameters, namely laser power and irradiation time, were optimized in order to achieve the optimum therapeutic effect of the combined scheme. The PDT alone resulted in 54.8% tumor necrosis, covering the upper cancer layers. When the PPTT was also applied, the total necrosis percentage raised up to 99.3%, while all of the surrounding studied organs (skin, heart, lungs and trachea, ribs, liver and spleen) were spared. The optimized values of the PPTT parameters were 550 mW of laser power and 70 s of irradiation time. Hence, the PPTT–PDT combination shows great potential in achieving high levels of tumor necrosis while sparing the healthy tissues.

Chemically Engineered Immune Cell-Derived Microrobots and Biomimetic Nanoparticles: Emerging Biodiagnostic and Therapeutic Tools

Over the past decades, considerable attention has been dedicated to the exploitation of diverse immune cells as therapeutic and/or diagnostic cell-based microrobots for hard-to-treat disorders. To date, a plethora of therapeutics based on alive immune cells, surface-engineered immune cells, immunocytes' cell membranes, leukocyte-derived extracellular vesicles or exosomes, and artificial immune cells have been investigated and a few have been introduced into the market. These systems take advantage of the unique characteristics and functions of immune cells, including their presence in circulating blood and various tissues, complex crosstalk properties, high affinity to different self and foreign markers, unique potential of their on-demand navigation and activity, production of a variety of chemokines/cytokines, as well as being cytotoxic in particular conditions. Here, the latest progress in the development of engineered therapeutics and diagnostics inspired by immune cells to ameliorate cancer, inflammatory conditions, autoimmune diseases, neurodegenerative disorders, cardiovascular complications, and infectious diseases is reviewed, and finally, the perspective for their clinical application is delineated.

Application of M1 macrophage as a live vector in delivering nanoparticles for in vivo photothermal treatment

Introduction

To enhance photothermal treatment (PTT) efficiency, a delivery method that uses cell vector for nanoparticles (NPs) delivery has drawn attention and studied widely in recent years.

Objectives

In this study, we demonstrated the feasibility of M1 activated macrophage as a live vector for delivering NPs and investigated the effect of NPs loaded M1 stimulated by Lipopolysaccharide on PTT efficiency in vivo.

Methods

M1 was used as a live vector for delivering NPs and further to investigate the effect of NPs loaded M1 on PTT efficiency. Non-activated macrophage (MФ) was stimulated by lipopolysaccharide (LPS) into M1 and assessed for tumor cell phagocytic capacity towards NPs

Results

We found M1 exhibited a 20-fold higher uptake capacity of NPs per cell volume and 2.9-fold more active infiltration into the tumor site, compared with non-activated macrophage MФ. We injected M1 cells peritumorally and observed that these cells penetrated into the tumor mass within 12 h. Then, we conducted PTT using irradiation of a near-infrared laser for 1 min at 1 W/cm². As a result, we confirmed that using M1 as an active live vector led to a more rapid reduction in tumor size within 1 day indicating that the efficacy of PTT with NPs-loaded M1 is higher than that with NPs-loaded MФ.

Conclusion

Our study demonstrated the potential role of M1 as a live vector for enhancing the feasibility of PTT in cancer treatment.

Macrophages as a Double-Edged Weapon: The Use of Macrophages in Cancer Immunotherapy and Understanding the Cross-Talk Between Macrophages and Cancer

Macrophages (Mϕs) play an essential role in maintaining body homeostasis. They perform dual functions produced by different subtypes. Mϕs not only fight against pathogens and foreign bodies such as bacteria or cancer cells but also participate in healing and repairing damaged tissue since they maintain both proinflammatory and anti-inflammatory effects sequentially. Tumors possess the ability to polarize Mϕs from proinflammatory M1 subtype to anti-inflammatory M2-like Mϕs called tumor-associated macrophages, which, in turn, help the tumors to acquire cancer hallmarks. Consequently, this polarization allows tumors to grow and spread. In this light, Mϕs have been a subject of intense study, and researchers have developed protocols to derive different Mϕs subtypes either as a new state-of-the-art therapeutic approach or to understand the cross-talk between cancer and Mϕs. In this review, we present the use of primary Mϕs in adoptive immunotherapy for cancer, illustrate the reciprocating interplay between cancer and Mϕs, and the resulting structural and functional change on both cell types. Furthermore, we summarize the recent cutting-edge approaches of using Mϕs in cancer immunotherapy.

Endocytosis-driven gold nanoparticle fractal rearrangement in cells and its influence on photothermal conversion

Cellular endocytosis and intracellular trafficking of nanoparticles induce dynamic rearrangements that profoundly modify the physical properties of nanoparticle and govern their biological outcomes when activated by external fields. The precise structure, organization, distribution, and density of gold nanoparticles (AuNPs) confined within intracellular compartments such as lysosomes have not been studied comprehensively, hampering the derivation of predictive models of their therapeutic activity within the cells of interest. By using transmission electron microscopy and small-angle X-ray scattering, we have determined that canonical spherical citrate-coated AuNPs in the 3-30 nm size range form fractal clusters in endolysosomes of macrophages, endothelial cells, and colon cancer cells. Statistical analysis revealed that the cluster size and endolysosome size are correlated but do not depend on the size of AuNPs unless larger preformed aggregates of AuNPs are internalized. Smaller AuNPs are confined in greater numbers in loose aggregates covering a higher fraction of the endolysosomes compared to the largest AuNPs. The fractal dimensions of intracellular clusters increased with the particle size, regardless of the cell type. We thus analyzed how these intracellular structure parameters of AuNPs affect their optical absorption and photothermal properties. We observed that a 2nd plasmon resonance band was shifted to the near-infrared region when the nanoparticle size and fractal dimensions of the intracellular cluster increased. This phenomenon of intracellular plasmon coupling is not directly correlated to the size of the intralysosomal cluster or the number of AuNPs per cluster but rather to the compacity of the cluster and the size of the individual AuNPs. The intracellular plasmon-coupling phenomenon translates to an efficient heating efficiency with the excitation of the three cell types at 808 nm, transforming the NIR-transparent canonical AuNPs with sizes below 30 nm into NIR-absorbing clusters in the tumor microenvironment. Harnessing the spontaneous clustering of spherical AuNPs by cells might be a more valuable strategy for theranostic purposes than deploying complex engineering to derive NIR-absorbent nanostructures out of their environment. Our paper sheds light on AuNP intracellular reorganization and proposes a general method to link their intracellular fates to their in situ physical properties exploited in medical applications.

Trojan horse monocyte-mediated delivery of conjugated polymer nanoparticles for improved photodynamic therapy of glioblastoma

Aim: To assess monocyte-based delivery of conjugated polymer nanoparticles (CPNs) for improved photodynamic therapy (PDT) in glioblastoma (GBM). Materials & methods: Human monocyte cells (THP-1) and murine monocytes isolated from bone marrow (mBMDMs) were employed as stealth CPN carriers to penetrate into GBM spheroids and an orthotopic model of the tumor. The success of PDT, using this cell-mediated targeting strategy, was determined by its effect on the spheroids. Results: CPNs did not affect monocyte viability in the absence of light and did not show nonspecific release after cell loading. Activated monocytes incorporated CPNs in a higher proportion than monocytes in their naive state, without a loss of cellular functionality. In vitro PDT efficacy using cell-mediated delivery was superior to that using non vehiculized CPNs. Conclusion: CPN-loaded monocytes could efficiently deliver CPNs into GBM spheroids and the orthotopic model. Improved PDT in spheroids was confirmed using this delivery strategy.

A Bird's-Eye View of Cell Sources for Cell-Based Therapies in Blood Cancers

: Hematological malignancies comprise over a hundred different types of cancers and account for around 6.5% of all cancers. Despite the significant improvements in diagnosis and treatment, many of those cancers remain incurable. In recent years, cancer cell-based therapy has become a promising approach to treat those incurable hematological malignancies with striking results in different clinical trials. The most investigated, and the one that has advanced the most, is the cell-based therapy with T lymphocytes modified with chimeric antigen receptors. Those promising initial results prepared the ground to explore other cell-based therapies to treat patients with blood cancer. In this review, we want to provide an overview of the different types of cell-based therapies in blood cancer, describing them according to the cell source.

Effects and side effects of plasmonic photothermal therapy in brain tissue

Background

Heat generated from plasmonic nanoparticles can be utilized in plasmonic photothermal therapy. A combination of near-infrared laser and plasmonic nanoparticles is compelling for the treatment of brain cancer, due to the efficient light-to-heat conversion and bio-compatibility. However, one of the challenges of plasmonic photothermal therapy is to minimize the damage of the surrounding brain tissue. The adjacent tissue can be damaged as a result of either absorption of laser light, thermal conductivity, nanoparticles diffusing from the tumor, or a combination hereof. Hence, we still lack the full understanding of the light–tissue interaction and, in particular, the thermal response.

Results

We tested the temperature change in three different porcine cerebral tissues, i.e., the stem, the cerebrum, and the cerebellum, under laser treatment. We find that the different tissues have differential optical and thermal properties and confirm the enhancement of heating from adding plasmonic nanoparticles. Furthermore, we measure the loss of laser intensity through the different cerebral tissues and stress the importance of correct analysis of the local environment of a brain tumor.

Conclusions

Our results stress the conclusion that a personalized analysis of the local environment is needed to balance the effect and side effects prior to plasmonic photothermal therapy.

Fractionated photothermal therapy in a murine tumor model: comparison with single dose

Purpose: Photothermal therapy (PTT) exploits the light-absorbing properties of nanomaterials such as silica-gold nanoshells (NS) to inflict tumor death through local hyperthermia. However, in in vivo studies of PTT, the heat distribution is often found to be heterogeneous throughout the tumor volume, which leaves parts of the tumor untreated and impairs the overall treatment outcome. As this challenges PTT as a one-dose therapy, this study here investigates if giving the treatment repeatedly, ie, fractionated PTT, increases the efficacy in mice bearing subcutaneous tumors.

Methods: The NS heating properties were first optimized in vitro and in vivo. Two fractionated PTT protocols, consisting of two and four laser treatments, respectively, were developed and applied in a murine subcutaneous colorectal tumor model. The efficacy of the two fractionated protocols was evaluated both by longitudinal monitoring of tumor growth and, at an early time point, by positron emission tomography (PET) imaging of ¹⁸F-labeled glucose analog ¹⁸F-FDG.

Results: Overall, there were no significant differences in tumor growth and survival between groups of mice receiving single-dose PTT and fractionated PTT in our study. Nonetheless, some animals did experience inhibited tumor growth or even complete tumor disappearance due to fractionated PTT, and these animals also showed a significant decrease in tumor uptake of ¹⁸F-FDG after therapy.

Conclusion: This study only found an effect of giving PTT to tumors in fractions compared to a single-dose approach in a few animals. However, many factors can affect the outcome of PTT, and reliable tools for optimization of treatment protocol are needed. Despite the modest treatment effect, our results indicate that ¹⁸F-FDG PET/CT imaging can be useful to guide the number of treatment sessions necessary.

Crushed Gold Shell Nanoparticles Labeled with Radioactive Iodine as a Theranostic Nanoplatform for Macrophage-Mediated Photothermal Therapy

Plasmonic nanostructure-mediated photothermal therapy (PTT) has proven to be a promising approach for cancer treatment, and new approaches for its effective delivery to tumor lesions are currently being developed. This study aimed to assess macrophage-mediated delivery of PTT using radioiodine-124-labeled gold nanoparticles with crushed gold shells (¹²⁴I-Au@AuCBs) as a theranostic nanoplatform. ¹²⁴I-Au@AuCBs exhibited effective photothermal conversion effects both in vitro and in vivo and were efficiently taken up by macrophages without cytotoxicity. After the administration of ¹²⁴I-Au@AuCB-labeled macrophages to colon tumors, intensive signals were observed at tumor lesions, and subsequent in vivo PTT with laser irradiation yielded potent antitumor effects. The results indicate the considerable potential of ¹²⁴I-Au@AuCBs as novel theranostic nanomaterials and the prominent advantages of macrophage-mediated cellular therapies in treating cancer and other diseases.

Disturbance of adhesomes by gold nanoparticles reveals a size- and cell type-bias

Gold nanoparticles (AuNP) have been thoroughly studied as multifunctional theranosis agents for cell imaging and cancer therapy as well as sensors due to their tunable physical and chemical properties. Although AuNP have proved to be safe in a wide concentration range, yet other important biological effects can arise in the sublethal window of treatment. This is especially pivotal to understand how AuNP can affect cell biology when labeling steps are needed for cell tracking in vivo, as nanoparticle loading can affect cell migratory/invasion ability, a function mediated by filamentous actin-rich nanometric structures collectively called adhesomes. It is noteworthy that, although numerous research studies have addressed the cell response to AuNP loading, yet none of them focuses on adhesome dynamics as a target of intracellular pathways affected by AuNP. We intend to study the collective dynamics of adhesive F-actin rich structures upon AuNP treatment as an approach to understand the complex AuNP-triggered modulation of migration/invasion related cellular functions. We demonstrated that citrate-coated spherical AuNP of different sizes (3, 11, 16, 30 and 40 nm) disturbed podosome-forming rosettes and the resulting extracellular matrix (ECM) degradation in a murine macrophage model depending on core size. This phenomenon was accompanied by a reduction in metalloproteinase MMP2 and an increment in metalloproteinase inhibitors, TIMP-1/2 and SerpinE1. We also found that AuNP treatment has opposite effects on focal adhesions (FA) in endothelial and mesenchymal stem cells. While endothelial cells reduced their mature FA number and ECM degradation rate upon AuNP treatment, mouse mesenchymal stem cells increased the number and size of mature FA and, therefore, the ECM degradation rate. Overall, AuNP appear to disturb adhesive structures and therefore migratory/invasive cell functions measured as ECM degradation ability, providing new insights into AuNP-cell interaction depending on cell type.

Macrophages as delivery vehicles for anticancer agents

The delivery of anticancer agents via passive approaches such as the enhanced permeability and retention effect is unlikely to achieve sufficient concentrations throughout the tumor volume for effective treatment. Cell-based delivery approaches using tumor tropic cells have the potential to overcome the limitations of passive approaches. Specifically, this review focuses on the use of monocytes/macrophages for the delivery of a variety of anticancer agents, including nanoparticles, chemotherapeutics and gene constructs. The efficacy of this delivery approach, both as monotherapy and in combination with light-based phototherapy modalities, has been demonstrated in numerous in vitro and animal studies, however, its clinical potential remains to be determined.

A biodegradable fluorescent nanohybrid for photo-driven tumor diagnosis and tumor growth inhibition

Specific targeting and phototriggered therapy in mouse model have recently emerged as the starting point of cancer theragnosis. Herein, we report a bioresponsive and degradable nanohybrid, a liposomal nanohybrid decorated with red emissive carbon dots, for localized tumor imaging and light-mediated tumor growth inhibition. Unsaturated carbon dots (C-dots) anchored to liposomes convert near-infrared (NIR) light into heat and also produce reactive oxygen species (ROS), demonstrating the capability of phototriggered cancer cell death and tumor regression. The photothermal and oxidative damage of breast tumor by the nonmetallic nanohybrid has also been demonstrated. Designed nanoparticles show excellent aqueous dispersibility, biocompatibility, light irradiated enhanced cellular uptake, release of reactive oxygen species, prolonged and specific tumor binding ability and good photothermal response (62 °C in 5 minutes). Safe and localized irradiation of 808 nm light demonstrates significant tumor growth inhibition and bioresponsive degradation of the fluorescent nanohybrid without affecting the surrounding healthy tissues.

Effects of peritumoral bevacizumab injection against oral squamous cell carcinoma in a nude mouse xenograft model: A preliminary study

Angiogenesis serves a crucial role in tumor growth. Vascular endothelial growth factor (VEGF) is a potent regulator of tumor angiogenesis and is highly expressed in oral squamous cell carcinoma (OSCC). Bevacizumab, which binds to VEGF-A, inhibits the biological activity of VEGF and is clinically administered by intravenous injection. As intravenous chemotherapy intensifies the side effects experienced by OSCC patients, an alternative treatment option is desirable, particularly for older patients with OSCC who present with systemic disease complications. Generally, local injections of antitumor agents enhance tumoricidal activity and decrease side effects. However, the antitumor effects of peritumoral bevacizumab injections in OSCC are not fully understood. Therefore, the present study examined the effects of peritumoral bevacizumab injections in an experimental nude mouse model of OSCC through immunohistochemical staining for cluster of differentiation (CD)31 and α-smooth muscle actin (α-SMA) and apoptosis assays. It was identified that peritumoral injections of bevacizumab significantly inhibited tumor growth in OSCC xenografts compared with peritumoral saline injections or no treatment (controls), and it was also revealed that treatment with bevacizumab significantly reduced CD31- and α-SMA-positive microvessel density (P<0.01) and increased level of tumor cell apoptosis (P<0.01) compared with the controls. In conclusion, these results collectively support the experimental basis for the clinical development of peritumoral bevacizumab injections for the treatment of OSCC.

Recent advances in cell-mediated nanomaterial delivery systems for photothermal therapy

Cell-mediated “Trojan Horse” delivery vehicles overcome the drug delivery barriers to transport nano-agents enhancing the efficiency of photothermal therapy.

Multifunctional Liposomes for Image-Guided Intratumoral Chemo-Phototherapy

Intratumoral (IT) drug injections reduce systemic toxicity, but delivered volumes and distribution can be inconsistent. To improve IT delivery paradigms, porphyrin-phospholipid (PoP) liposomes are passively loaded with three hydrophilic cargos: sulforhodamine B, a fluorophore; gadolinium-gadopentetic acid, a magnetic resonance (MR) agent; and oxaliplatin, a colorectal cancer chemotherapeutic. Liposome composition is optimized so that cargo is retained in serum and storage, but is released in less than 1 min with exposure to near infrared light. Light-triggered release occurs with PoP-induced photooxidation of unsaturated lipids and all cargos release concurrently. In subcutaneous murine colorectal tumors, drainage of released cargo is delayed when laser treatment occurs 24 h after IT injection, at doses orders of magnitude lower than systemic ones. Delayed light-triggering results in substantial tumor shrinkage relative to controls a week following treatment, although regrowth occurs subsequently. MR imaging reveals that over this time frame, pools of liposomes within the tumor migrate to adjacent regions, possibly leading to altered spatial distribution during triggered drug release. Although further characterization of cargo loading and release is required, this proof-of-principle study suggests that multimodal theranostic IT delivery approaches hold potential to both guide injections and interpret outcomes, in particular when combined with chemo-phototherapy.

In vivo photothermal treatment with real-time monitoring by optical fiber-needle array

Photothermal treatment (PTT) using gold nanoshells (gold-NSs) is accepted as a method for treating cancer. However, owing to restrictions in therapeutic depth and skin damage caused by excessive light exposure, its application has been limited to lesions close to the epidermis. Here, we demonstrate an in vivo PTT method that uses gold-NSs with a flexible optical fiber-needle array (OFNA), which is an array of multiple needles in which multimode optical fibers are inserted, one in each, for light delivery. The light for PTT was directly administrated to subcutaneous tissues through the OFNA, causing negligible thermal damage to the skin. Enhancement of light energy delivery assisted by the OFNA in a target area was confirmed by investigation using artificial tissues. The ability of OFNA to treat cancer without causing cutaneous thermal damage was also verified by hematoxylin and eosin (H&E) staining and optical coherence tomography in cancer models in mice. In addition, the OFNA allowed for observation of the target site through an imaging fiber bundle. By imaging the activation of the injected gold-NSs, we were able to obtain information on the PTT process in real-time.

Macrophage-based cell therapies: The long and winding road

In the quest for better medicines, attention is increasingly turning to cell-based therapies. The rationale is that infused cells can provide a targeted therapy to precisely correct a complex disease phenotype. Between 1987 and 2010, autologous macrophages (MΦs) were used in clinical trials to treat a variety of human tumors; this approach provided a modest therapeutic benefit in some patients but no lasting remissions. These trials were initiated prior to an understanding of: the complexity of MΦ phenotypes, their ability to alter their phenotype in response to various cytokines and/or the environment, and the extent of survival of the re-infused MΦs. It is now known that while inflammatory MΦs can kill tumor cells, the tumor environment is able to reprogram MΦs into a tumorigenic phenotype; inducing blood vessel formation and contributing to a cancer cell growth-promoting milieu. We review how new information enables the development of large numbers of ex vivo generated MΦs, and how conditioning and gene engineering strategies are used to restrict the MΦ to an appropriate phenotype or to enable production of therapeutic proteins. We survey applications in which the MΦ is loaded with nanomedicines, such as liposomes ex vivo, so when the drug-loaded MΦs are infused into an animal, the drug is released at the disease site. Finally, we also review the current status of MΦ biodistribution and survival after transplantation into an animal. The combination of these recent advances opens the way for improved MΦ cell therapies.

Cell Mediated Photothermal Therapy of Brain Tumors

Gold based nanoparticles with strong near infra-red (NIR) absorption are ideally suited for photothermal therapy (PTT) of brain tumors. The goal of PTT is to induce rapid heating in tumor tissues while minimizing thermal diffusion to normal brain. PTT efficacy is sensitively dependent on both nanoparticle concentration and distribution in tumor tissues. Nanoparticle delivery via passive approaches such as the enhanced permeability and retention (EPR) effect is unlikely to achieve sufficient nanoparticle concentrations throughout tumor volumes required for effective PTT. A simple approach for improving tumor biodsitribution of nanoparticles is the use of cellular delivery vehicles. Specifically, this review focuses on the use of monocytes/macrophages (Mo/Ma) as gold nanoparticle delivery vectors for PTT of brain tumors. Although the efficacy of this delivery approach has been demonstrated in both in vitro and animal PTT studies, its clinical potential for the treatment of brain tumors remains uncertain.