Evaluation of the enhanced permeability and retention effect in the early stages of lymph node metastasis

Using imaging modalities to predict nanoparticle distribution and treatment efficacy in solid tumors: The growing role of ultrasound

Nanomedicine in oncology has not had the success in clinical impact that was anticipated in the early stages of the field's development. Ideally, nanomedicines selectively accumulate in tumor tissue and reduce systemic side effects compared to traditional chemotherapeutics. However, this has been more successful in preclinical animal models than in humans. The causes of this failure to translate may be related to the intra- and inter-patient heterogeneity of the tumor microenvironment. Predicting whether a patient will respond positively to treatment prior to its initiation, through evaluation of characteristics like nanoparticle extravasation and retention potential in the tumor, may be a way to improve nanomedicine success rate. While there are many potential strategies to accomplish this, prediction and patient stratification via noninvasive medical imaging may be the most efficient and specific strategy. There have been some preclinical and clinical advances in this area using MRI, CT, PET, and other modalities. An alternative approach that has not been studied as extensively is biomedical ultrasound, including techniques such as multiparametric contrast-enhanced ultrasound (mpCEUS), doppler, elastography, and super-resolution processing. Ultrasound is safe, inexpensive, noninvasive, and capable of imaging the entire tumor with high temporal and spatial resolution. In this work, we summarize the in vivo imaging tools that have been used to predict nanoparticle distribution and treatment efficacy in oncology. We emphasize ultrasound imaging and the recent developments in the field concerning CEUS. The successful implementation of an imaging strategy for prediction of nanoparticle accumulation in tumors could lead to increased clinical translation of nanomedicines, and subsequently, improved patient outcomes. This article is categorized under: Diagnostic Tools In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery Emerging Technologies.

Docetaxel administered through a novel lymphatic drug delivery system (LDDS) improved treatment outcomes for lymph node metastasis

Recently, sentinel lymph nodes (LNs) have been recognized as a starting point of hematogenous metastasis; thus, an increase in the control rate of LN metastasis is expected to improve the survival rate. Although surgical treatment and radiation therapy are commonly used for the radical treatment of LNs, these treatments are associated with lymphedema, pain, and an extended hospital stay. In a recent mouse study, activation of metastatic tumors in distant organs was reported after removing LNs, with or without metastasis to the LNs. Thus, there is the necessity for cancer treatment that can replace LN removal. Here, we evaluated the treatment efficacy of lymphatic drug delivery system (LDDS) with osmotic pressure and viscosity escalated Docetaxel at the early stage of LN metastasis. MXH10/Mo/lpr mice were inoculated with mouse breast cancer cells into Subiliac LN to create the metastatic mouse model. Docetaxel was injected into mouse mammary carcinoma cells inoculated LN as a single shot (SS) or double shot (DS) to understand the therapeutic mechanism of a single shot or double shot intervention using an in vivo imaging system, histology, and qPCR. The results showed that the DS administration of docetaxel at 1,960 kPa (12 mPa∙s) had better therapeutic outcomes with increased complete response and improved survival with reduced adverse events. The results also revealed that administration of a DS of docetaxel enhances differentiation of T helper cells, and improves survival and therapeutic outcomes. From a safety perspective, LDDS-administered DS of low-concentration docetaxel without any other anticancer treatments to LNs a novel approach to cancer management of LN metastasis. We emphasize that LDDS is a groundbreaking method of delivering anticancer drugs specifically to cancer susceptible LNs and is designed to enhance the effectiveness of cancer treatment while minimizing side effects.

Assessing Tumor Microenvironment Characteristics and Stratifying EPR with a Nanobubble Companion Nanoparticle via Contrast-Enhanced Ultrasound Imaging

The tumor microenvironment is characterized by dysfunctional endothelial cells, resulting in heightened vascular permeability. Many nanoparticle-based drug delivery systems attempt to use this enhanced permeability combined with impaired lymphatic drainage (a concept known as the 'enhanced permeability and retention effect' or EPR effect) as the primary strategy for drug delivery, but this has not proven to be as clinically effective as anticipated. The specific mechanisms behind the inconsistent clinical outcomes of nanotherapeutics have not been clearly articulated, and the field has been hampered by a lack of accessible tools to study EPR-associated phenomena in clinically relevant scenarios. While medical imaging has tremendous potential to contribute to this area, it has not been broadly explored. This work examines, for the first time, the use of multiparametric dynamic contrast-enhanced ultrasound (CEUS) with a novel nanoscale contrast agent to examine tumor microenvironment characteristics noninvasively and in real-time. We demonstrate that CEUS imaging can: (1) evaluate tumor microenvironment features and (2) be used to help predict the distribution of doxorubicin-loaded liposomes in the tumor parenchyma. CEUS using nanobubbles (NBs) was carried out in two tumor types of high (LS174T) and low (U87) vascular permeability, and time-intensity curve (TIC) parameters were evaluated in both models prior to injection of doxorubicin liposomes. Consistently, LS174T tumors showed significantly different TIC parameters, including area under the rising curve (2.7x), time to peak intensity (1.9x) and decorrelation time (DT, 1.9x) compared to U87 tumors. Importantly, the DT parameter successfully predicted tumoral nanoparticle distribution (r = 0.86 ± 0.13). Ultimately, substantial differences in NB-CEUS generated parameters between LS174T and U87 tumors suggest that this method may be useful in determining tumor vascular permeability and could be used as a biomarker for identifying tumor characteristics and predicting sensitivity to nanoparticle-based therapies. These findings could ultimately be applied to predicting treatment efficacy and to evaluating EPR in other diseases with pathologically permeable vasculature.

Tumor Abnormality-Oriented Nanomedicine Design

Anticancer nanomedicines have been proven effective in mitigating the side effects of chemotherapeutic drugs. However, challenges remain in augmenting their therapeutic efficacy. Nanomedicines responsive to the pathological abnormalities in the tumor microenvironment (TME) are expected to overcome the biological limitations of conventional nanomedicines, enhance the therapeutic efficacies, and further reduce the side effects. This Review aims to quantitate the various pathological abnormalities in the TME, which may serve as unique endogenous stimuli for the design of stimuli-responsive nanomedicines, and to provide a broad and objective perspective on the current understanding of stimuli-responsive nanomedicines for cancer treatment. We dissect the typical transport process and barriers of cancer drug delivery, highlight the key design principles of stimuli-responsive nanomedicines designed to tackle the series of barriers in the typical drug delivery process, and discuss the "all-into-one" and "one-for-all" strategies for integrating the needed properties for nanomedicines. Ultimately, we provide insight into the challenges and future perspectives toward the clinical translation of stimuli-responsive nanomedicines.

Intralymphatic injection of chemotherapy drugs modulated with glucose improves their anticancer effect

Lymph node metastasis (LNM) has a significant impact on cancer prognosis, emphasizing the need for effective treatment strategies. This study investigated the potential use of high osmotic pressure drug solutions with low viscosity administration using a lymphatic drug delivery system (LDDS) to improve LNM treatment outcomes. The hypothesis was that injection of epirubicin or nimustine at high osmotic pressure but without altered viscosity would enhance drug retention and accumulation in LNs, thereby improving the efficacy of treatment. Biofluorescence analysis revealed enhanced drug accumulation and retention in LNs after administration using LDDS compared to intravenous (i.v) injection. Histopathological results demonstrated minimal tissue damage in the LDDS groups. Pharmacokinetic analysis revealed an improved treatment response with higher drug accumulation and retention in LNs. The LDDS approach offers the potential for greatly reduced side effects of chemotherapy drugs, lower dosage requirements and crucially increased drug retention in LNs. The results highlight the promise of high osmotic pressure drug solutions with low viscosity administrated using the LDDS for enhancing the treatment efficacy of LN metastasis. Further research and clinical trials are warranted to validate these results and optimize the clinical translation of this novel treatment technique.

Targeting endothelial permeability in the EPR effect

The characteristics of the primary tumor blood vessels and the tumor microenvironment drive the enhanced permeability and retention (EPR) effect, which confers an advantage towards enhanced delivery of anti-cancer nanomedicine and has shown beneficial effects in preclinical models. Increased vascular permeability is a landmark feature of the tumor vessels and an important driver of the EPR. The main focus of this review is the endothelial regulation of vascular permeability. We discuss current challenges of targeting vascular permeability towards clinical translation and summarize the structural components and mechanisms of endothelial permeability, the principal mediators and signaling players, the targeted approaches that have been used and their outcomes to date. We also critically discuss the effects of the tumor-infiltrating immune cells, their interplay with the tumor vessels and the impact of immune responses on nanomedicine delivery, the impact of anti-angiogenic and tumor-stroma targeting approaches, and desirable nanoparticle design approaches for greater translational benefit.

A core-satellite micellar system against primary tumors and their lymphatic metastasis through modulation of fatty acid metabolism blockade and tumor-associated macrophages

Lymph nodes (LNs) are the initial sanctuary of various metastatic tumor cells, and thus a precise lymphatic drug delivery strategy is necessary for the effective inhibition of metastasis. However, the complex biological barriers have restrained the drug delivery to tumor-draining lymph nodes (TDLNs). Metastatic tumor cells would undergo metabolic adaptation towards fatty acid oxidation (FAO) upon reaching the lipid-rich LNs. Herein, to inhibit primary tumors and their lymphatic metastasis, a core-satellite matrix metalloproteinase 2 (MMP-2) responsive micellar system was developed for sequential delivery of paclitaxel (PTX) and the metabolism-regulating drug etomoxir (ET) to tumors and TDLNs, respectively. Upon arrival at the tumor microenvironment (TME), the small satellite micelle encapsulating ET was detached from the core micelle in response to MMP-2, which not only drained to TDLNs via tumor-draining lymphatic vessels and inhibited the FAO of metastatic tumor cells, but also blocked M2-like macrophage polarization in the TME. Meanwhile, the core micelle containing PTX could largely accumulate in the TME and kill tumor cells. In an orthotopic 4T1 breast cancer model, the tumor and TDLN dual-targeted core-satellite micellar system effectively inhibited the growth of the primary tumor and alleviated immune suppression by blocking macrophage polarization. More importantly, tumor lymphatic metastasis was suppressed through FAO metabolic regulation. This strategy provides a promising approach for TDLN targeted therapy against breast cancer and its lymphatic metastasis.

The tumor EPR effect for cancer drug delivery: Current status, limitations, and alternatives

Over the past three decades, the enhanced permeability and retention (EPR) effect has been considered the basis of tumor-targeted drug delivery. Various cancer nanomedicines, including macromolecular drugs, have been designed to utilize this mechanism for preferential extravasation and accumulation in solid tumors. However, such nanomedicines have not yet achieved convincing therapeutic benefits in clinics. Increasing evidence suggests that the EPR effect is over-represented in human tumors, especially in metastatic tumors. This review covers the evolution of the concept, the heterogeneity and limitation of the EPR effect in clinical realities, and prospects for alternative strategies independent of the EPR effect.

Combination therapy of lymphatic drug delivery and total body irradiation in a metastatic lymph node and lung mouse model

Chemotherapy using a lymphatic drug delivery system (LDDS) targeting lymph nodes (LNs) in the early stage of metastasis has a superior antitumor effect to systemic chemotherapy. An LDDS produces a higher drug retention rate and tissue selectivity in LNs. To expand the therapeutic coverage of LDDS from local treatment of metastatic LNs to prevention of distant metastases, the combination of treatment with therapies that enhance systemic tumor immune effects is an important therapeutic strategy. Recently, total body irradiation (TBI) has been shown to activate immune responses and alter the tumor microenvironment. Here we show that combination therapy with TBI and LDDS improves the antitumor effect of metastatic LNs and lung metastasis. Tumor cells were inoculated into the subiliac LN (SiLN) to induce metastasis into the proper axillary LN (PALN) and lung in a mouse model. TBI was carried out on day 4 after inoculation using a gamma irradiator. Lymphatic drug delivery into the accessory axillary LN was used to treat PALN. In vivo bioluminescence imaging, high-frequency ultrasound, and histology showed that combination therapy using TBI (total dose 1.0 Gy once) and the LDDS suppressed tumor growth in LNs and lung metastases and was more effective than using LDDS or TBI alone. Quantitative RT-PCR of spleens after combination therapy revealed increased expression of CD4, CD8, and IL-12b, indicating an activated immune response. The results show that combination therapy with TBI and LDDS is a method to improve the efficacy of LN metastases and distant metastases therapy and is a promising novel approach to treat cancer patients.

Drug formulation augments the therapeutic response of carboplatin administered through a lymphatic drug delivery system

Treatment of metastatic lymph nodes (LNs) is challenging due to their unique architecture and biophysical traits. Systemic chemotherapy fails to impede tumor progression in LNs due to poor drug uptake and retention by LNs, resulting in fatal systemic metastasis. To effectively treat LN metastasis, achieving specific and prolonged retention of chemotherapy drugs in the tumor-draining LNs is essential. The lymphatic drug-delivery system (LDDS) is an ultrasound-guided drug-delivery methodology for administration of drugs to LNs that addresses these requirements. However, early-stage metastatic LNs have an additional set of drug transport barriers, such as elevated intranodal pressure and viscosity, that negatively impact drug diffusion. In the present study, using formulations of elevated osmotic pressure and viscosity relative to saline, we sought to favorably alter the LN's physical environment and study its impact on pharmacokinetics and consequently the therapeutic efficacy of carboplatin delivered using the LDDS. Our study confirmed the capability of a drug formulation with elevated osmotic pressure and viscosity to alter the architecture of LNs, as it caused notable expansion of the lymphatic sinus. Additionally, the study delineated an optimal range of osmotic pressure and viscosity, centered around 1897 kPa and 11.5 mPa·s, above and below which therapeutic efficacy was found to decline markedly. These findings suggest that formulation osmotic pressure and viscosity are parameters that require critical consideration as they can both hinder and promote tumorigenesis. The facile formulation reported here has wide-ranging applicability across cancer spectrums and is thus anticipated to be of great clinical benefit.

Experience with Photodynamic Therapy Using Indocyanine Green Liposomes for Refractory Cancer

We reported the development of an effective cancer treatment using a multidisciplinary treatment, including photodynamic therapy (PDT) with indocyanine green (ICG) liposomes and a combination of Lentinula edodes mycelia (LEM) and hydrogen gas inhalation therapy. ICG liposomes were prepared by adding 5 mg of ICG to 50 mL liposomes. Later, 25 mL of ICG liposomes were diluted with 250 mL of 5% glucose solution and administered intravenously to the patient. We selected the multi-laser delivery system (MLDS), a laser irradiator for performing PDT. Further, the patients received a combination of LEM and hydrogen gas inhalation therapy throughout the treatment. We reported two cases of PDT therapy, one with middle intrathoracic esophagus carcinoma and the other with hypopharyngeal cancer. In the first case, the MLDS laser was directly attached to the endoscope and directed to the cancer area with wavelengths of 810 nm. After the treatment, a biopsy demonstrated no tumor recurrence. In the second case, the patient was treated with endovascular PDT using ICG liposomes and MLDS fiber optics. Later, tumor shrinkage was demonstrated after the first round and disappeared after six months. In conclusion, the present findings suggest that the effect of PDT using ICG liposomes with LEM and hydrogen gas may eradicate cancer without burdening patients by enhancing tumor immunity.

Mesenchymal stem cells: A living carrier for active tumor-targeted delivery

The strategy of using mesenchymal stem cells (MSCs) as a living carrier for active delivery of therapeutic agents targeting tumor sites has been attempted in a wide range of studies to validate the feasibility and efficacy for tumor treatment. This approach reveals powerful tumor targeting and tumor penetration. In addition, MSCs have been confirmed to actively participate in immunomodulation of the tumor microenvironment. Thus, MSCs are not inert delivery vehicles but have a strong impact on the fate of tumor cells. In this review, these active properties of MSCs are addressed to highlight the advantages and challenges of using MSCs for tumor-targeted delivery. In addition, some of the latest examples of using MSCs to carry a variety of anti-tumor agents for tumor-targeted therapy are summarized. Recent technologies to improve the performance and safety of this delivery strategy will be introduced. The advances, applications, and challenges summarized in this review will provide a general understanding of this promising strategy for actively delivering drugs to tumor tissues.

Gadolinium-Coated Mesoporous Silica Nanoparticle for Magnetic Resonance Imaging

Magnetic resonance molecular imaging can provide anatomic, functional and molecular information. However, because of the intrinsically low sensitivity of magnetic resonance imaging (MRI), high-performance MRI contrast agents are required to generate powerful image information for image diagnosis. Herein, we describe a novel T 1 contrast agent with magnetic-imaging properties facilitated by the gadolinium oxide (Gd2O3) doping of mesoporous silica nanoparticles (MSN). The size, morphology, composition, MRI relaxivity (r 1 ), surface area and pore size of these nanoparticles were evaluated following their conjugation with Gd2O3 to produce Gd2O3@MSN. This unique structure led to a significant enhancement in T 1 contrast with longitudinal relaxivity (r 1 ) as high as 51.85 ± 1.38 mM-1s-1. Gd2O3@MSN has a larger T 1 relaxivity than commercial gadolinium diethylene triamine pentaacetate (Gd-DTPA), likely due to the geometrical confinement effect of silica nanoparticles. These results suggest that we could successfully prepare a novel high-performance T 1 contrast agent, which may be a potential candidate for in-vivo MRI.

Intratumoral lymphatic endothelial cell infiltration reflecting lymphangiogenesis is counterbalanced by immune responses and better cancer biology in the breast cancer tumor microenvironment

Lymphangiogenesis, the generation of new lymphatic vessels from existing ones, results from the dynamic interactions of lymphatic endothelial cells and the tumor microenvironment (TME). It is well known that lymphangiogenesis occurs during the initial stage of metastasis in various types of malignant tumors. However, it is currently not used as a biomarker partially because gold standard method to quantify it is labor and cost intensive. We hypothesized that the quantity of intratumoral lymphatic endothelial cells (iLECs) in the TME is an indicator of lymphangiogenesis and a predictor of metastatic potential and overall survival in breast cancer. We analyzed a total of 4145 breast cancer patients from the Cancer Genome Atlas (TCGA) and GSE96058 by quantifying their iLECs using the xCell algorithm, and correlated these scores with patient survival, tumor grade, and cancer stage. We also assessed various pro- and anti-cancer gene sets for each tumor to characterize tumor behavior and aggressiveness. As we expected, high-iLEC breast cancer demonstrated enriched lymphoangiogenesis and angiogenesis gene sets and was associated with increased expressions of related genes. Also enriched were inflammatory response and immune response-related gene sets; IL2/STAT5 pathway, IL6/JAK/STAT3 pathway, TNFα pathway, allograft rejection, and complement as well as cancer stemness related gene sets like Notch signaling, Hedgehog signaling, epithelial mesenchymal transition, and Wnt beta-catenin signaling. Tumors with high-iLEC showed higher proportions of stromal cells and fewer anti-cancer immune cells. On the other hand, iLEC score did not correlate with patient survival or lymph node metastasis. Surprisingly, breast cancers with fewer iLECs demonstrated enriched E2F Targets, G2M Checkpoint, MYC Targets v1, and MTORC1 signaling which are cancer cell proliferation-related gene sets and exhibited an abundance of pro-cancer immune cells. The amount of iLEC correlated inversely with Ki67 expression and histological grade, which is in agreement that low-iLEC breast cancer was associated with enhanced cancer cell proliferation. In conclusion, while iLECs can be used as a surrogate for lymphangiogenesis in breast cancer, low-iLEC tumors also exhibit features which correspond to aggressive tumor biology, which may explain why the amount of iLECs was not associated with patient survival in our cohorts.

Intranodal delivery of modified docetaxel: Innovative therapeutic method to inhibit tumor cell growth in lymph nodes

Delivery of chemotherapeutic agents into metastatic lymph nodes (LNs) is challenging as they are unevenly distributed in the body. They are difficult to access via traditional systemic routes of drug administration, which produce significant adverse effects and result in low accumulation of drugs into the cancerous LN. To improve the survival rate of patients with LN metastasis, a lymphatic drug delivery system (LDDS) has been developed to target metastatic LN by delivering chemotherapy agents into sentinel LN (SLN) under ultrasound guidance. The LDDS is an advanced method that can be applied in the early stage of the progression of tumor cells in the SLN before tumor mass formation has occurred. Here we investigated the optimal physicochemical ranges of chemotherapeutic agents’ solvents with the aim of increasing treatment efficacy using the LDDS. We found that an appropriate osmotic pressure range for drug administration was 700–3,000 kPa, with a viscosity < 40 mPa⋅s. In these physicochemical ranges, expansion of lymphatic vessels and sinuses, drug retention, and subsequent antitumor effects could be more precisely controlled. Furthermore, the antitumor effects depended on the tumor progression stage in the SLN, the injection rate, and the volumes of administered drugs. We anticipate these optimal ranges to be a starting point for developing more effective drug regimens to treat metastatic LN with the LDDS.

Protocols for the Evaluation of a Lymphatic Drug Delivery System Combined with Bioluminescence to Treat Metastatic Lymph Nodes

Bioluminescence (BL) imaging is a powerful non-invasive imaging modality widely used in a broad range of biological disciplines for many types of measurements. The applications of BL imaging in biomedicine are diverse, including tracking bacterial progression, research on gene expression patterns, monitoring tumor cell growth/regression or treatment responses, determining the location and proliferation of stem cells, and so on. It is particularly valuable when studying tissues at depths of 1 to 2 cm in mouse models during preclinical research. Here we describe the protocols for the therapeutic evaluation of a lymphatic drug delivery system (LDDS) using an in vivo BL imaging system (IVIS) for the treatment of metastatic lymph nodes (LNs) with 5-fluorouracil (5-FU). The LDDS is a method that directly injects anticancer drugs into sentinel LNs (SLNs) and delivers them to their downstream LNs. In the protocol, we show that metastases in the proper axillary LN (PALN) are induced by the injection of luciferase-expressing tumor cells into the subiliac LN (SiLN) of MXH10/Mo-lpr/lpr (MXH10/Mo/lpr) mice. 5-FU is injected using the LDDS into the accessory axillary LN (AALN) to treat tumor cells in the PALN after the tumor cell growth is confirmed in the PALN. The tumor growth and therapeutic effects are evaluated by IVIS. This method can be used to evaluate tumor growth and efficacy of anticancer drugs/particles, radiotherapy, surgery, and/or a combination of these methods in various experimental procedures in the oncology field.

Photodynamic Theranostics of Central Lung Cancer: Capabilities of Early Diagnosis and Minimally Invasive Therapy (Review)

The aim of the study was to assess the prospects for central lung cancer (CLC) screening using fluorescent diagnostics and its treatment by endobronchial photodynamic therapy (PDT). Bronchoscopic fluorescent diagnostics using chlorin e6 photosensitizers and a developed instrumental system enable to reveal tumor changes in large bronchi mucosa at early stages, and a developed PDT technique performed under fluorescent control helps achieve personalized treatment. Such an approach is considered as a theranostic technique - photodynamic theranostics. central lung cancer screening requires a fluorescent dye characterized by availability and can be used directly within the examination. Indocyanine green can be used as a dye, its peculiarity is the necessity to excite and record fluorescence in the near-infrared (NIR) wavelength band. First experiments using NIR bands to diagnose a bronchoscopic system showed the detectability of tumor areas using on-site bronchoscopic photodynamic theranostics, which consists in NIR imaging of tumor foci when a standard dose of indocyanine green is administered during the examination.

Conclusion

Further progress of early diagnostics and minimally invasive CLC therapy will be determined by the development of new photosensitizers, which should be characterized by a high absorption band in NIR area, quick accumulation in a tumor, high yield of single oxygen in NIR illumination, bright fluorescence, high potential in terms of the induction of an anti-tumor immune response.

Characterizing perfusion defects in metastatic lymph nodes at an early stage using high-frequency ultrasound and micro-CT imaging

A perfusion defect in a metastatic lymph node (LN) can be visualized as a localized area of low contrast on contrast-enhanced CT, MRI or ultrasound images. Hypotheses for perfusion defects include abnormal hemodynamics in neovascular vessels or a decrease in blood flow in pre-existing blood vessels in the parenchyma due to compression by LN tumor growth. However, the mechanisms underlying perfusion defects in LNs during the early stage of LN metastasis have not been investigated. We show that tumor mass formation with very few microvessels was associated with a perfusion defect in a non-enlarged LN at the early stage of LN metastasis in a LN adenopathy mouse (LN size circa 10 mm). We found in a mouse model of LN metastasis, induced using non-keratinizing tumor cells, that during the formation of the perfusion defect in a non-enlarged LN, the number of blood vessels ≤ 50 μm in diameter decreased, while those of > 50 μm in diameter increased. The methods used were contrast-enhanced high-frequency ultrasound and contrast-enhanced micro-CT imaging systems, with a maximum spatial resolution of > 30 μm. Furthermore, we found no tumor angiogenesis or oxygen partial pressure (pO₂) changes in the metastatic LN. Our results demonstrate that the perfusion defect appears to be a specific form of tumorigenesis in the LN, which is a vascular-rich organ. We anticipate that a perfusion defect on ultrasound, CT or MRI images will be used as an indicator of a non-enlarged metastatic LN at an early stage.

Artificial Light at Night Reduces Anxiety-like Behavior in Female Mice with Exacerbated Mammary Tumor Growth

Simple Summary

Artificial light at night, initially assumed to be innocuous, is associated with an increased risk for developing mood disorders, sleep disturbances, and cancer. However, the influence of ALAN on affective behavior in tumor-bearing mice has not been investigated. Here, we demonstrate that ALAN reduces the latency to tumor onset and increases terminal tumor volume. Additionally, tumor-bearing mice housed in dark nights exhibit increased anxiety-like behavior which is prevented via housing in ALAN.

Abstract

Artificial light at night (ALAN) is a pervasive phenomenon. Although initially assumed to be innocuous, recent research has demonstrated its deleterious effects on physiology and behavior. Exposure to ALAN is associated with disruptions to sleep/wake cycles, development of mood disorders, metabolic disorders, and cancer. However, the influence of ALAN on affective behavior in tumor-bearing mice has not been investigated. We hypothesize that exposure to ALAN accelerates mammary tumor growth and predict that ALAN exacerbates negative affective behaviors in tumor-bearing mice. Adult (>8 weeks) female C3H mice received a unilateral orthotropic injection of FM3A mouse mammary carcinoma cells (1.0 × 10⁵ in 100 μL) into the fourth inguinal mammary gland. Nineteen days after tumor inoculation, mice were tested for sucrose preference (anhedonia-like behavior). The following day, mice were subjected to an open field test (anxiety-like behavior), followed by forced swim testing (depressive-like behavior). Regardless of tumor status, mice housed in ALAN increased body mass through the first ten days. Tumor-bearing ALAN-housed mice demonstrated reduced latency to tumor onset (day 5) and increased terminal tumor volume (day 21). Exposure to ALAN reduced sucrose preference independent of tumor status. Additionally, tumor-bearing mice housed in dark nights demonstrated significantly increased anxiety-like behavior that was normalized via housing in ALAN. Together, these data reaffirm the negative effects of ALAN on tumorigenesis and demonstrate the potential anxiolytic effect of ALAN in the presence of mammary tumors.

Improving selective targeting to cancer-associated fibroblasts by modifying liposomes with arginine based materials

A library of arginine-like surface modifiers was tested to improve the targetability of DOPE:DOPC liposomes towards myofibroblasts in a tumour microenvironment. Liposomes were characterised using zeta potential and dynamic light scattering. Cell viability remained unchanged for all liposomes. Liposomes were encapsulated using doxorubicin (DOX) with an encapsulation efficiency >94%. The toxicity of DOX-loaded liposomes was calculated via half-maximal inhibitory concentration (IC₅₀) for fibroblasts and myofibroblasts. These liposomes resulted in significantly lower IC₅₀-values for myofibroblasts compared to fibroblasts, making them more toxic towards the myofibroblasts. Furthermore, a significant increase in cell internalisation was observed for myofibroblasts compared to fibroblasts, using fluorescein-loaded liposomes. Most importantly, a novel regression model was constructed to predict the IC₅₀-values for different modifications using their physicochemical properties. Fourteen modifications (A-N) were used to train and validate this model; subsequently, this regression model predicted IC₅₀-values for three new modifications (O, P and Q) for both fibroblasts and myofibroblasts. Predicted and measured IC₅₀-values showed no significant difference for fibroblasts. For myofibroblasts, modification O showed no significant difference. This study demonstrates that the tested surface modifications can improve targeting to myofibroblasts in the presence of fibroblasts and hence are suitable drug delivery vehicles for myofibroblasts in a tumour microenvironment.

Role of lymphatic endothelial cells in the tumor microenvironment-a narrative review of recent advances

Background

As lymphatic vessel is a major route for solid tumor metastasis, they are considered an essential part of tumor drainage conduits. Apart from forming the walls of lymphatic vessels, lymphatic endothelial cells (LECs) have been found to play multiple other roles in the tumor microenvironment, calling for a more in-depth review. We hope that this review may help researchers gain a detailed understanding of this fast-developing field and shed some light upon future research.

Methods

To achieve an informative review of recent advance, we carefully searched the Medline database for English literature that are openly published from the January 1995 to December 2020 and covered the topic of LEC or lymphangiogenesis in tumor progression and therapies. Two different authors independently examined the literature abstracts to exclude possible unqualified ones, and 310 papers with full texts were finally retrieved.

Results

In this paper, we discussed the structural and molecular basis of tumor-associated LECs, together with their roles in tumor metastasis and drug therapy. We then focused on their impacts on tumor cells, tumor stroma, and anti-tumor immunity, and the molecular and cellular mechanisms involved. Special emphasis on lung cancer and possible therapeutic targets based on LECs were also discussed.

Conclusions

LECs can play a much more complex role than simply forming conduits for tumor cell dissemination. Therapies targeting tumor-associated lymphatics for lung cancer and other tumors are promising, but more research is needed to clarify the mechanisms involved.

Genetically modified bacteria for targeted phototherapy of tumor

Live attenuated bacteria have been used as target vehicles for genetic therapy of malignant carcinoma because they can be reprogrammed by following simple genetic rules and have the ability to target tumor hypoxic region. In this research, noninvasive Escherichia coli (E. Coli) is genetically modified through the plasmid transfection to afford E. Coli(p) with overexpressed human catalase for catalyzing H₂O₂ into O₂ in the tumor site. The produced O₂ is consequently converted to cytotoxic ¹O₂ under near-infrared (NIR) light irradiation for photodynamic therapy. Chlorin e6 (Ce6) is chosen as the photosensitizer for its excellent photodynamic ability, and polydopamine (pDA) is employed to encapsulate Ce6 for its good biosafety, photothermal ability, and adhesion capacity with bacteria. Dopamine polymerizes in the presence of Ce6 to form pDA/Ce6, and then E. Coli(p) is coated with pDA/Ce6 to afford the final E. Coli(p)/pDA/Ce6. The obtained system is intravenously administrated for selective accumulation and replication in the hypoxic tumor. NIR light irradiation is introduced to enable photothermal and O₂-enhanced photodynamic therapy. On account of complementary combination, the system exhibits efficient antitumor effect in vitro and in vivo. Thus, the integration of genetically modified bacteria with pDA/Ce6 presents a promising application potential for precise tumor inhibition.

Study of the physicochemical properties of drugs suitable for administration using a lymphatic drug delivery system

Lymph node (LN) metastasis is thought to account for 20‐30% of deaths from head and neck cancer. The lymphatic drug delivery system (LDDS) is a new technology that enables the injection of drugs into a sentinel LN (SLN) during the early stage of tumor metastasis to treat the SLN and secondary metastatic LNs. However, the optimal physicochemical properties of the solvent used to carry the drug have not been determined. Here, we show that the osmotic pressure and viscosity of the solvent influenced the antitumor effect of cisplatin (CDDP) in a mouse model of LN metastasis. Tumor cells were inoculated into the proper axillary LN (PALN), and the LDDS was used to inject CDDP solution into the subiliac LN (SiLN) to treat the tumor cells in the downstream PALN. CDDP dissolved in saline had no therapeutic effects in the PALN after it was injected into the SiLN using the LDDS or into the tail vein (as a control). However, CDDP solution with an osmotic pressure of ~ 1,900 kPa and a viscosity of ~ 12 mPa⋅s suppressed tumor growth in the PALN after it was injected into the SiLN using the LDDS. The high osmotic pressure dilated the lymphatic vessels and sinuses to enhance drug flow in the PALN, and the high viscosity increased the retention of CDDP in the PALN. Our results demonstrate that optimizing the osmotic pressure and viscosity of the solvent can enhance the effects of CDDP, and possibly other anticancer drugs, after administration using the LDDS.

Optimization of the delivery of molecules into lymph nodes using a lymphatic drug delivery system with ultrasound

Conventional treatment for lymph node (LN) metastasis such as systemic chemotherapy have notable disadvantages that lead to the development of unwanted effects. Previously, we have reported the lymphatic administration of drugs into metastatic LNs using a lymphatic drug delivery system (LDDS). However, prior studies of the LDDS have not attempted to optimize the conditions for efficient drug delivery. Here, we investigated the influence of several factors on the efficiency of drug delivery by a LDDS in conjunction with ultrasound (US). First, the effect of the injection rate on delivery efficiency was evaluated. Fluorescent molecules injected into an upstream LN were delivered more effectively into a downstream LN when a lower injection rate was used. Second, the influence of molecular weight on drug delivery efficiency was determined. We found that molecules with a molecular weight >10,000 were poorly delivered into the LN. Finally, we assessed whether the administration route affected the delivery efficiency. We found that the delivery efficiency was higher when molecules were administered into an upstream LN that was close to the target LN. These findings revealed the importance of a drug's physical properties if it is to be administered by LDDS to treat LN metastasis.

What Went Wrong with Anticancer Nanomedicine Design and How to Make It Right

The three design criteria of anticancer nanomedicines to improve anticancer efficacy and to reduce toxicity have been debated for decades: (1) Nanomedicines increase drug accumulation through enhanced permeability and retention (EPR) in tumors to improve anticancer efficacy. (2) Long systemic circulation of nanomedicines with high plasma concentration reduces reticuloendothelial system (RES) clearance and decreases drug accumulation in the normal organs to reduce toxicity, and to enhance the EPR effect. (3) A universal nanodelivery platform based on EPR and long systemic circulation can be developed to deliver different anticancer drugs. Although these criteria have repeatedly been confirmed in preclinical xenograft cancers, the majority of anticancer nanomedicines have failed to improve clinical efficacy, while the clinical efficacies/safety of successful nanomedicines are inconsistent with these design criteria. First, the debate over tumor EPR may have mixed two different questions and missed more clinically relevant comparisons for nanomedicines versus free drugs. When tumors are compared with normal tissues, tumor EPR has been confirmed in both mouse xenograft tumors and human cancers. However, nanomedicines may not enhance drug accumulation in human tumors compared with free drugs, despite outstanding improvement in preclinical cancers. Heterogeneity of enhanced permeability and retention in human cancers occurs for small/large molecules and nanomedicines, which cannot fully explain the poor translation of nanomedicines' efficacy from preclinical cancer models to cancer patients. Second, long-circulation nanomedicine should not be used as a universal design criterion because it does not further improve tumor accumulation by tumor EPR in human patients nor universally reduce distribution in normal organs. In contrast, nanomedicines change the drug tissue distribution to alter anticancer efficacy/safety. Third, a universal nanodelivery platform that uses the same design criteria for different drugs is not feasible. Rather, drug-specific nanodelivery systems are required to overcome the intrinsic shortcomings of delivered drugs, which are determined by the physicochemical, pharmacokinetic, and pharmacodynamic properties of the delivered drugs and nanocarriers to improve their efficacy/safety.

Intranodal pressure of a metastatic lymph node reflects the response to lymphatic drug delivery system

Cancer metastasis to lymph nodes (LNs) almost certainly contributes to distant metastasis. Elevation of LN internal pressure (intranodal pressure, INP) during tumor proliferation is associated with a poor prognosis for patients. We have previously reported that a lymphatic drug delivery system (LDDS) allows the direct delivery of anticancer drugs into the lymphatic system and is a promising treatment strategy for early‐stage LN metastasis. However, methods for evaluating the treatment effects have not been established. Here, we used a mouse model of MXH10/Mo‐lpr/lpr, which develops a systemic swelling of LNs, and murine malignant fibrous histiocytoma‐like (KM‐Luc/GFP) cells or murine breast cancer (FM3A‐Luc) cells inoculated into the subiliac LN of mice to produce a tumor‐bearing LN model. The changes in INP during intranodal tumor progression and after treatment with cis‐dichlorodiammineplatinum(II) (CDDP) using an LDDS were measured. We found that tumor progression was associated with an increase in INP that occurred independently of LN volume changes. The elevation in INP was suppressed by CDDP treatment with the LDDS when intranodal tumor progression was significantly inhibited. These findings indicate that INP is a useful parameter for monitoring the therapeutic effect in patients with LN metastasis who have been given drugs using an LDDS, which will serve to manage cancer metastasis treatment and contribute to an improved quality of life for cancer patients.

Tumor cell death in orthotopic breast cancer model by NanoALA: a novel perspective on photodynamic therapy in oncology

Aim: Nano-5-aminolevulic acid (NanoALA)-mediated photodynamic therapy (PDT), an oil-in-water polymeric nanoemulsion of ALA, was evaluated in a murine model of breast cancer. Materials & methods: Analysis of ALA-derived protoporphyrin IX production and acute toxicity test, biocompatibility and treatment efficacy, and long-term effect of NanoALA-PDT on tumor progression were performed. Results: The nanoformulation favored the prodrug uptake by tumor cells in a shorter time (1.5 h). As a result, the adverse effects were negligible and the response rates for primary mammary tumor control were significantly improved. Tumor progression was slower after NanoALA-PDT treatment, providing longer survival. Conclusion: NanoALA is a good proactive drug candidate for PDT against cancer potentially applied as adjuvant/neoadjuvant intervention strategy for breast cancer.

Overcoming Physiological Barriers to Nanoparticle Delivery-Are We There Yet?

The exploitation of nanosized materials for the delivery of therapeutic agents is already a clinical reality and still holds unrealized potential for the treatment of a variety of diseases. This review discusses physiological barriers a nanocarrier must overcome in order to reach its target, with an emphasis on cancer nanomedicine. Stages of delivery include residence in the blood stream, passive accumulation by virtue of the enhanced permeability and retention effect, diffusion within the tumor lesion, cellular uptake, and arrival at the site of action. We also briefly outline strategies for engineering nanoparticles to more efficiently overcome these challenges: Increasing circulation half-life by shielding with hydrophilic polymers, such as PEG, the limitations of PEG and potential alternatives, targeting and controlled activation approaches. Future developments in these areas will allow us to harness the full potential of nanomedicine.

Enhanced Primary Tumor Penetration Facilitates Nanoparticle Draining into Lymph Nodes after Systemic Injection for Tumor Metastasis Inhibition

Lymph nodes (LNs) are normally the primary site of tumor metastasis, and effective delivery of chemotherapeutics into LNs through systemic administration is critical for metastatic cancer treatment. Here, we uncovered that improved perfusion in a primary tumor facilitates nanoparticle translocation to LNs for inhibiting tumor metastasis. On the basis of our finding that an iCluster platform, which undergoes size reduction from ∼100 nm to ∼5 nm at the tumor site, markedly improved particle perfusion in the interstitium of the primary tumor, we further revealed in the current study that such tumor-specific size transition promoted particle intravasation into tumor lymphatics and migration into LNs. Quantitative analysis indicated that the drug deposition in LNs after iCluster treatment was significantly higher in the presence of a primary tumor in comparison with that after primary tumor resection. Early intervention of metastatic 4T1 tumors with iCluster chemotherapy and subsequent surgical resection of the primary tumor resulted in significantly extending animal survival, with 4 out of the 10 mice remaining completely tumor-free for 110 days. Additionally, in the more clinical relevant late metastatic model, iCluster inhibited the metastatic colonies to the lungs and extended animal survival time. This finding provides insights into the design of more effective nanomedicines for treating metastatic cancer.

Indocyanine green binds to DOTAP liposomes for enhanced optical properties and tumor photoablation

Indocyanine green (ICG) is a clinically-approved near infrared (NIR) dye used for optical imaging. The dye is only slightly soluble in water and is prone to aggregation in saline solutions, so that alternative formulations can improve photophysical performance. Numerous nanoscale formulations of ICG have been described in the literature, but we sought to develop an approach that does not require additional purification steps. Pre-formed liposomes incorporating 45 mol% of the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) rapidly bind ICG, resulting in enhanced NIR optical properties. ICG binding is dependent on the amount of DOTAP incorporated in the liposomes. A dye-to-lipid mass ratio of [0.5 : 25] is sufficient for full complexation, without additional purification steps following mixing. NIR absorption, fluorescence intensity, and photoacoustic signals are increased for the liposome-bound dye. Not only is the optical character enhanced by simple mixing of ICG with liposomes, but retention in 4T1 mammary tumors is observed following intratumor injection, as assessed by fluorescence and photoacoustic imaging. Subsequent photothermal therapy with 808 nm laser irradiation is effective and results in tumor ablation without regrowth for at least 30 days. Thus, ICG optical properties and photothermal ablation outcomes can be improved by mixing the dye with pre-formed DOTAP liposomes in conditions that result in full dye-binding to the liposomes.

The effect of anti-IL-6 receptor antibody for the treatment of McH-lpr/lpr-RA1 mice that spontaneously developed destructive arthritis and enthesitis

Background

McH-lpr/lpr-RA1 mice are a new strain of mice which spontaneously develop destructive arthritis and enthesitis in the ankle. There is no published data that drug treatment has been trialed on these mice. This study examined the effect of the mouse anti-IL-6 receptor antibody, MR16–1, for the treatment of arthritis and enthesitis in McH-lpr/lpr-RA1 mice.

Methods

Male McH-lpr/lpr-RA1 mice were randomly divided into control and treatment groups. MR16–1 was administered from 10 weeks of age for the treatment group. Saline was applied for the control group. The drug was administered once a week, at an initial dose of 2 mg, then maintained at 0.5 mg once per week thereafter. The effects were evaluated by the histopathological synovitis score, in vivo imaging using indocyanine green liposomes, and analysis of the gene expression of inflammatory cytokines.

Results

Tissue analyses were carried out at 14, 17 and 20 weeks of age. The synovitis scores of treated groups were significantly lower compared with those of the control group at 14 and 17 weeks of age. The kappa coefficient was 0.77. However, progression of entheseal ossification persisted in the MR16–1 treated group. In vivo imaging using indocyanine green liposomes showed significant decreases in signal intensities of treated groups at week 14, but no significant differences were observed at week 18. Blood serum amyloid A levels in treated groups were significantly lower at 17 weeks of age. The gene expression levels of Tnf and Il17 were also significantly lower in MR16–1 treated groups.

Conclusions

Administration of the anti-IL-6 receptor antibody is effective for the treatment of synovitis and bone destruction of McH-lpr/lpr-RA1 mice. McH-lpr/lpr-RA1 mice may be a suitable experimental model for the development of new treatments for destructive arthritis and enthesitis. IL-6 signal blockade could contribute to the treatment of destructive arthritis, and further studies should be carried out to confirm its potential in the prevention of enthesopathy developed to ossification.

Hyaluronidase-Responsive Mesoporous Silica Nanoparticles with Dual-Imaging and Dual-Target Function

Nanoparticle-based drug delivery systems are among the most popular research topics in recent years. Compared with traditional drug carriers, mesoporous silica nanoparticles (MSN) offer modifiable surfaces, adjustable pore sizes and good biocompatibility. Nanoparticle-based drug delivery systems have become a research direction for many scientists. With the active target factionalized, scientists could deliver drug carriers into cancer cells successfully. However, drugs in cancer cells could elicit drug resistance and induce cell exocytosis. Thus, the drug cannot be delivered to its pharmacological location, such as the nucleus. Therefore, binding the cell membrane and the nuclear target on the nanomaterial so that the anticancer drug can be delivered to its pharmacological action site is our goal. In this study, MSN-EuGd was synthesized by doping Eu3+ and Gd3+ during the synthesis of MSN. The surface of the material was then connected to the TAT peptide as the nucleus target for targeting the cancer nucleus and then loaded with the anticancer drug camptothecin (CPT). Then, the surface of MSN-EuGd was bonded to the hyaluronic acid as an active target and gatekeeper. With this system, it is possible and desirable to achieve dual imaging and dual targeting, as well as to deliver drugs to the cell nucleus under a hyaluronidase-controlled release. The experimental approach is divided into three parts. First, we conferred the material with fluorescent and magnetic dual-imaging property by doping Eu3+ and Gd3+ into the MSN. Second, modification of the cell membrane target molecule and the nucleus target molecule occurred on the surface of the nanoparticle, making the nanoparticle a target drug carrier. Third, the loading of drug molecules into the carrier gave the entire carrier a specific target profile and enabled the ability to treat cancer. In this study, we investigated the basic properties of the drug carrier, including physical properties, chemical properties, and in vitro tests. The result showed that we have successfully designed a drug delivery system that recognizes normal cells and cancer cells and has good anticancer effects.

Treatment of false-negative metastatic lymph nodes by a lymphatic drug delivery system with 5-fluorouracil

Metastatic lymph nodes (LNs) may be the origin of systemic metastases. It will be important to develop a strategy that prevents systemic metastasis by treating these LNs at an early stage. False‐negative metastatic LNs, which are found during the early stage of metastasis development, are those that contain tumor cells but have a size and shape similar to LNs that do not host tumor cells. Here, we show that 5‐fluorouracil (5‐FU), delivered by means of a novel lymphatic drug delivery system (LDDS), can treat LNs with false‐negative metastases in a mouse model. The effects of 5‐FU on four cell lines were investigated using in vitro cytotoxicity and cell survival assays. The therapeutic effects of LDDS‐administered 5‐FU on false‐negative metastatic LNs were evaluated using bioluminescence imaging, high‐frequency ultrasound (US), and histology in MHX10/Mo‐lpr/lpr mice. These experimental animals develop LNs that are similar in size to human LNs. We found that all cell lines showed sensitivity to 5‐FU in the in vitro assays. Furthermore, a concentration‐dependent effect of 5‐FU to inhibit tumor growth was observed in tumor cells with low invasive growth characteristics, although a significant reduction in metastatic LN volume was not detected in MHX10/Mo‐lpr/lpr mice. Adverse effects of 5‐FU were not detected. 5‐Fluorouracil administration with a LDDS is an effective treatment method for false‐negative metastatic LNs. We anticipate that the delivery of anticancer drugs by a LDDS will be of great benefit in the prevention and treatment of cancer metastasis via LNs.

Nasopharyngeal cancer combination chemoradiation therapy based on folic acid modified, gefitinib and yttrium 90 co-loaded, core-shell structured lipid-polymer hybrid nanoparticles

Current treatment of advanced-stage nasopharyngeal carcinoma (NPC) is not satisfactory. Here, we developed a folic acid (FA) modified, gefitinib (GEF) and yttrium 90 (Y90) co-loaded, core-shell structured lipid-polymer hybrid nanoparticles (FA-GEF-Y90-LPNP). The size and zeta potential, drug release behavior, and uptake by tumor cells were investigated. The antitumor efficiency and toxicity of LPNP were evaluated in cancer cells and in tumor bearing mice. FA-GEF-Y90-LPNP with a mean size of 150 nm and zeta potential of -40 mV was able to enhance the accumulation in the NPC cells and exhibited the highest cytotoxicity. The AUC and T_1/2 of FA-GEF-Y90-LPNP group was 217.62 ± 10.32 mg/L.h and 12.09 ± 0.43 h, respectively. FA-GEF-Y90-LPNP exhibited the best in vivo tumor inhibition ability, leading to a 221.2 ± 13.5 mm³ of tumor volume at day 21. FA-GEF-Y90-LPNP treatment resulted in almost no difference in the body weight. This may be the evidence that the systemic toxicity of FA-GEF-Y90-LPNP is low and may be used as safety system for the treatment of NPC.

Plasmonic MoO3-x nanoparticles incorporated in Prussian blue frameworks exhibit highly efficient dual photothermal/photodynamic therapy

Development of near infrared (NIR) light-responsive nanomaterials for high performance multimodal phototherapy within a single nanoplatform is still challenging in technology and biomedicine. Herein, a new phototherapeutic nanoagent based on FDA-approved Prussian blue (PB) functionalized oxygen-deficient molybdenum oxide nanoparticles (MoO_3-x NPs) is strategically designed and synthesized by a facile one-pot size/morphology-controlled process. The as-prepared PB-MoO_3-x nanocomposites (NCs) with a uniform particle size of ∼90 nm and high water dispersibility exhibited strong optical absorption in the first biological window, which is induced by plasmon resonance in an oxygen-deficient MoO_3-x semiconductor. More importantly, PB-MoO_3-x NCs not only exhibited a high photothermal conversion efficiency of ∼63.7% and photostability but also offered a further approach for the generation of reactive oxygen species (ROS) upon singular NIR light irradiation which significantly improved the therapeutic efficiency of the PB agent. Furthermore, PB-MoO_3-x NCs showed a negligible cytotoxic effect in the dark, but an excellent therapeutic effect toward two triple-negative breast cancer (TNBC) cell lines at a low concentration (20 μg mL^-1) of NCs and a moderate NIR laser power density. Additionally, efficient tumor ablation and metastasis inhibition in a 4T1 TNBC mouse tumor model can also be realized by synergistic photothermal/photodynamic therapy (PTT/PDT) under a single continuous NIR wave laser. Taken together, this study paved the way for the use of a single nanosystem for multifunctional therapy.

Targeted Nanomedicine to Treat Bone Metastasis

Bone metastases are common complications of solid tumors, particularly those of the prostate, breast, and lungs. Bone metastases can lead to painful and devastating skeletal-related events (SREs), such as pathological fractures and nerve compressions. Despite advances in treatment for cancers in general, options for bone metastases remain inadequate and generally palliative. Anticancer drugs (chemotherapy and radiopharmaceuticals) do not achieve therapeutic concentrations in the bone and are associated with dose-limiting side effects to healthy tissues. Nanomedicines, with their tunable characteristics, have the potential to improve drug targeting to bone metastases while decreasing side effects for their effective treatment. In this review, we present the current state of the art for nanomedicines to treat bone metastases. We also discuss new treatment modalities enhanced by nanomedicine and their effects on SREs and disease progression.

Optimal range of injection rates for a lymphatic drug delivery system

The lymphatic drug delivery system (LDDS) is a new technique that permits the injection of drugs into a sentinel lymph node (SLN) at an early stage of tumor metastasis, thereby treating metastasis in the SLN and its secondary lymph nodes (LNs). The quantity of drug required for a LDDS is much smaller than that needed for systemic chemotherapy. However, the relationship between the rate of drug injection into a SLN and the amount of drug reaching the secondary LNs has not been investigated. In this study, we used an MXH10/Mo-lpr/lpr mouse model to show that the optimal rate for the injection of a fluorescent dye by a LDDS was 10 to 80 μL/min. An injection rate of 10 to 80 μL/min was able to fill the downstream LN. However, an injection rate of 100 μL/min drove the fluorescent dye into the efferent lymphatic vessels and thoracoepigastric vein, decreasing the amount of dye retained in the downstream LN. Bolus injection (defined as an injection rate of 2400 μL/min) was unable to deliver fluorescent dye into the downstream LN. These results agree with the impulse values calculated from the injection pressures in the upstream LN. We anticipate that our findings will facilitate the development of a LDDS for use in the clinic.

Superselective Drug Delivery Using Doxorubicin-Encapsulated Liposomes and Ultrasound in a Mouse Model of Lung Metastasis Activation

Conventional treatment of lymph node metastasis involves dissection of the tumor and regional lymph nodes, but this may cause activation of latent metastatic tumor cells. However, there are few reports on animal models regarding the activation of latent metastatic tumor cells and effective methods of treating activated tumor cells. Here, we report the use of a superselective drug delivery system in a mouse model of lung metastasis in which activated tumor cells are treated with doxorubicin-encapsulated liposomes (DOX-LP) and ultrasound. The axillary lymph node was injected with DOX-LP and exposed to ultrasound so that the released DOX would be delivered from the axillary lymph node to the metastatic lung via the subclavian vein, heart and pulmonary artery. The size of the DOX-LP was optimized to a diameter of 460 nm using indocyanine green-encapsulated liposomes, and the ultrasound intensity was 0.5 W/cm². We found that compared with DOX or DOX-LP alone, the superselective drug delivery system was effective in the treatment of metastasis in both the lung and axillary lymph node. We anticipate that this superselective drug delivery system will be a starting point for the development of new techniques for treating lung metastasis in the clinical setting. Furthermore, the superselective drug delivery system may be used to screen novel drugs for the treatment of lung cancer and investigate the mechanisms of tumor cell activation after resection of a primary tumor or lymph nodes.

Antilung cancer effect of ergosterol and cisplatin-loaded liposomes modified with cyclic arginine-glycine-aspartic acid and octa-arginine peptides

BACKGROUND

Lung cancer is one of the most important diseases threatening human health, and targeted therapy has become the main research direction. This work, therefore, aimed to develop cyclic arginine-glycine-aspartic (RGD) and octa-arginine (R8) peptide-modified ergosterol (ERG)-combined cisplatin (diamminedichloridoplatinum(II) [DDP]) liposomes (LIP) as a drug delivery system.

METHODS

Soybean phospholipids (SPC) and cholesterol (Chol) were selected to prepare different LIPs: ERG-loaded LIP (ERG-LIP), DDP and ERG-LIP (DDP/ERG-LIP), R8 peptide-modified DDP and ERG-LIP (R8-DDP/ERG-LIP), and cyclic RGD and R8-DDP/ERG-LIP (RGD/R8-DDP/ERG-LIP). The quality, tumor sphere penetrating ability, in vitro cellular uptake, mechanism of cellular uptake, and in vitro cytotoxicity of RGD/R8-DDP/ERG-LIP were evaluated.

RESULTS

The LIP quality evaluation revealed that RGD/R8-DDP/ERG-LIP is round with a double-layer structure. The average particle size, dispersion coefficient of the polydispersity index (PDI), and zeta potential of RGD/R8-DDP/ERG-LIP were 155.2 ± 8.7 nm, 0.102, and 4.74 ± 0.7 mV, respectively. Furthermore, the LIPs were stable in the serum, and obviously inhibited the growth of A549 lung cancer cells with RGD/R8-DDP/ERG-LIP exhibiting the strongest inhibitory effect. The highest cellular uptake rate, which was at 4 hours, was exhibited by RGD/R8-DDP/ERG-LIP in a concentration-dependent manner.

CONCLUSION

The results showed that LIP uptake by A549 cells was mainly by the clathrin-mediated endocytosis pathway (chlorpromazine). The results also suggest that RGD/R8-DDP/ERG-LIP might be a promising drug delivery system to improve antilung cancer drug effect and tumor-targeting in vitro.

Advanced sensing, imaging, and therapy nanoplatforms based on Nd3+-doped nanoparticle composites exhibiting upconversion induced by 808 nm near-infrared light

Malignant tumors are currently the leading cause of death worldwide, followed by cardiovascular and cerebrovascular diseases. Although various methods, such as blood examination, tissue biopsy, and radiography, for tumor detection, exist, these techniques still require further refinement. Researchers have recently explored the use of novel adjuvant methods, specifically luminescence imaging detection, for the detection of tumors. The light-triggered approach is less invasive and induces fewer side effects than traditional detection methods. This paper highlights recent advances in the design, property tuning, and applications of nanoparticles that exhibit upconversion under 808 nm excitation. When doped with neodymium ions, upconverted nanoparticles gain the ability to absorb 808 nm light. The advantageous unique features of 808 nm light include deep tissue penetration and limited thermal side effects. The 808 nm-excited upconverted nanoparticles exhibit superior potential for use in biosensing, bioimaging, therapy, and three-dimensional display. Thus, innovative theranostic nanoplatforms can be developed by incorporating 808 nm-excited upconverted nanoparticles with phototherapy agents. Such a composite technique is expected to possess the individual advantages of each material.

Evaluation of the enhanced permeability and retention effect in the early stages of lymph node metastasis

Most solid cancers spread to new sites via the lymphatics before hematogenous dissemination. However, only a small fraction of an intravenously administered anti‐cancer drug enters the lymphatic system to reach metastatic lymph nodes (LN). Here, we show that the enhanced permeability and retention (EPR) effect is not induced during the early stages of LN metastasis. Luciferase‐expressing tumor cells were injected into the subiliac LN of the MXH10/Mo‐lpr/lpr mouse to induce metastasis to the proper axillary LN (PALN). In vivo biofluorescence imaging was used to confirm metastasis induction and to quantify the EPR effect, measured as PALN accumulation of intravenously injected indocyanine green (ICG) liposomes. PALN blood vessel volume changes were measured by contrast‐enhanced high‐frequency ultrasound imaging. The volume and density of blood vessels in the PALN increased until day 29 after inoculation, whereas the LN volume remained constant. ICG retention was first detected on day 29 post‐inoculation. While CD31‐positive cells increased up to day 29 post‐inoculation, α‐smooth muscle actin‐positive cells were detected on day 29 post‐inoculation for the first time. These results suggest that the EPR effect was not induced in the early stages of LN metastasis; therefore, systemic chemotherapy would likely not be beneficial during the early stages of LN metastasis. The development of an alternative drug delivery system, independent of the EPR effect, is required for the treatment of LN metastasis.