Imaging metastasis using an integrin-targeting chain-shaped nanoparticle

A detailed insight of the tumor targeting using nanocarrier drug delivery system

Human struggle against the deadly disease conditions is continued since ages. The contribution of science and technology in fighting against these diseases cannot be ignored exclusively due to the invention of novel procedure and products, extending their size ranges from micro to nano. Recently nanotechnology has been gaining more consideration for its ability to diagnose and treat different cancers. Different nanoparticles have been used to evade the issues related with conservative anticancer delivery systems, including their nonspecificity, adverse effects and burst release. These nanocarriers including, solid lipid nanoparticles (SLNs), liposomes, nano lipid carriers (NLCs), nano micelles, nanocomposites, polymeric and magnetic nanocarriers, have brought revolutions in antitumor drug delivery. Nanocarriers improved the therapeutic efficacy of anticancer drugs with better accumulation at the specific site with sustained release, improved bioavailability and apoptosis of the cancer cells while bypassing the normal cells. In this review, the cancer targeting techniques and surface modification on nanoparticles are discussed briefly with possible challenges and opportunities. It can be concluded that understanding the role of nanomedicine in tumor treatment is significant, and therefore, the modern progressions in this arena is essential to be considered for a prosperous today and an affluent future of tumor patients.

Transcytosis-Inducing Multifunctional Albumin Nanomedicines with Deep Penetration Ability for Image-Guided Solid Tumor Treatment

Transcytosis is an active transcellular transportation pathway that has garnered interest for overcoming the limited deep penetration of nanomedicines in solid tumors. In this study, a charge-convertible nanomedicine that facilitates deep penetration into solid tumors via transcytosis is designed. It is an albumin-based calcium phosphate nanomedicine loaded with IR820 (mAlb-820@CaP) for high-resolution photoacoustic imaging and enhanced photothermal therapy. Biomineralization on the surface stabilizes the albumin-IR820 complex during circulation and provides calcium ions (Ca2+ ) for tissue penetration on degradation in an acidic environment. pH-triggered transcytosis of the nanomedicine enabled by caveolae-mediated endocytosis and calcium ion-induced exocytosis in 2D cellular, 3D spheroid, and in vivo tumor models is demonstrated. Notably, the extravasation and penetration ability of the nanomedicine is observed in vivo using a high-resolution photoacoustic system, and nanomedicine shows the most potent photothermal antitumor effect in vivo. Overall, the strategy provides a versatile theragnosis platform for both noninvasive photoacoustic imaging and high therapeutic efficiency resulting from deep penetration of nanomedicine.

Can targeted nanoparticles distinguish cancer metastasis from inflammation?

Targeting ligands have been widely used to increase the intratumoral accumulation of nanoparticles and their uptake by cancer cells. However, these ligands aim at targets that are often also upregulated in inflamed tissues. Here, we assessed the ability of targeted nanoparticles to distinguish metastatic cancer from sites of inflammation. Using common targeting ligands and a 60-nm liposome as a representative nanoparticle, we generated three targeted nanoparticle (NP) variants that targeted either fibronectin, folate, or αvβ3 integrin, whose deposition was compared against that of standard untargeted NP. Using fluorescently labeled NPs and ex vivo fluorescence imaging of organs, we assessed the deposition of the NPs into the lungs of mice modeling 4 different biological landscapes, including healthy lungs, aggressive metastasis in lungs, dormant/latent metastasis in lungs, and lungs with general pulmonary inflammation. Among the four NP variants, fibronectin-targeting NP and untargeted NP exhibited the highest deposition in lungs harboring aggressive metastases. However, the deposition of all targeted NP variants in lungs with metastasis was similar to the deposition in lungs with inflammation. Only the untargeted NP was able to exhibit higher deposition in metastasis than inflammation. Moreover, flow-cytometry analysis showed all NP variants accumulated predominantly in immune cells rather than cancer cells. For example, the number of NP+ macrophages and dendritic cells was 16-fold greater than NP+ cancer cells in the case of fibronectin-targeting NP. Overall, targeted NPs were unable to distinguish cancer metastasis from general inflammation, which may have clinical implications to the nanoparticle-mediated delivery of cancer drugs.

Lighting up metastasis process before formation of secondary tumor by phosphorescence imaging

Metastasis is the leading cause of cancer-related deaths; until now, the detection of tumor metastasis is mainly located at the period that secondary tumors have been formed, which usually results in poor prognosis. Thus, fast and precise positioning of organs, where tumor metastases are likely to occur at its earliest stages, is essential for improving patient outcomes. Here, we demonstrated a phosphorescence imaging method by organic nanoparticles to detect early tumor metastasis progress with microenvironmental changes, putting the detection period ahead to the formation of secondary tumors. In the orthotopic and simulated hematological tumor metastasis models, the microenvironmental changes could be recognized by phosphorescence imaging at day 3, after tumor implantation in liver or intravenous injection of cancer cells. It was far ahead those of other reported imaging methods with at least 7 days later, providing a sensitive and convenient method to monitor tumor metastases at the early stage.

Nanoparticles in the diagnosis and treatment of cancer metastases: Current and future perspectives

Metastasis accounts for greater than 90% of cancer-related deaths. Despite recent advancements in conventional chemotherapy, immunotherapy, targeted therapy, and their rational combinations, metastatic cancers remain essentially untreatable. The distinct obstacles to treat metastases include their small size, high multiplicity, redundancy, therapeutic resistance, and dissemination to multiple organs. Recent advancements in nanotechnology provide the numerous applications in the diagnosis and prophylaxis of metastatic diseases, including the small particle size to penetrate cell membrane and blood vessels and their capacity to transport complex molecular 'cargo' particles to various metastatic regions such as bones, brain, liver, lungs, and lymph nodes. Indeed, nanoparticles (NPs) have demonstrated a significant ability to target specific cells within these organs. In this regard, the purpose of this review is to summarize the present state of nanotechnology in terms of its application in the diagnosis and treatment of metastatic cancer. We intensively reviewed applications of NPs in fluorescent imaging, PET scanning, MRI, and photoacoustic imaging to detect metastasis in various cancer models. The use of targeted NPs for cancer ablation in conjunction with chemotherapy, photothermal treatment, immuno therapy, and combination therapy is thoroughly discussed. The current review also highlights the research opportunities and challenges of leveraging engineering technologies with cancer cell biology and pharmacology to fabricate nanoscience-based tools for treating metastases.

Coating a Self-Assembly Nanoconstruct with a Neutrophil Cell Membrane Enables High Specificity for Triple Negative Breast Cancer Treatment

Breast cancer is one of the most commonly diagnosed cancers in American women. Triple negative breast cancer is among the most advanced and aggressive forms of breast cancer. Treatment options are limited for such cancers, making chemotherapy a convenient and effective treatment. Although these therapies can reduce morbidity and mortality, it is often followed by systemic side effects or relapse. Nanoparticles (NPs) have been considered for drug delivery approaches due to their ability to target various disease sites. Herein, we aim to develop a biomimetic NP construct (cell membrane-cloaked NPs) that exhibits specific affinity with triple negative breast cancer cells. In this regard, we designed biomimetic supramolecular nanoconstructs composed of a poly(vinyl pyrrolidone)-tannic acid (PVP-TA NPs/ PVT NPs) core and biofunctionalized with neutrophil cell membranes (PVT-NEU NPs). In this study, we have synthesized a PVT-NEU NP construct, characterized it, and evaluated it for improved targeting and therapeutic benefits in in vitro and in vivo models. Analysis of PVT-NEU NPs confirms the presence of the core of PVP-TA NPs coated with activated human neutrophil membranes. The study results confirmed that PVT-NEU NPs demonstrated an enhanced interaction and targeting with the tumor cells, thus improving the therapeutic activity of a model therapeutic agent (paclitaxel). Altogether, this study suggests the potential of biomimetic NPs as a promising therapeutic option for targeted drug delivery for advanced-stage breast cancer and other similar diseased conditions.

An Updated Review on EPR-Based Solid Tumor Targeting Nanocarriers for Cancer Treatment

The enhanced permeability and retention (EPR) effect in cancer treatment is one of the key mechanisms that enables drug accumulation at the tumor site. However, despite a plethora of virus/inorganic/organic-based nanocarriers designed to rely on the EPR effect to effectively target tumors, most have failed in the clinic. It seems that the non-compliance of research activities with clinical trials, goals unrelated to the EPR effect, and lack of awareness of the impact of solid tumor structure and interactions on the performance of drug nanocarriers have intensified this dissatisfaction. As such, the asymmetric growth and structural complexity of solid tumors, physicochemical properties of drug nanocarriers, EPR analytical combination tools, and EPR description goals should be considered to improve EPR-based cancer therapeutics. This review provides valuable insights into the limitations of the EPR effect in therapeutic efficacy and reports crucial perspectives on how the EPR effect can be modulated to improve the therapeutic effects of nanomedicine.

1D Colloidal chains: recent progress from formation to emergent properties and applications

Integrating nanoscale building blocks of low dimensionality (0D; i.e., spheres) into higher dimensional structures endows them and their corresponding materials with emergent properties non-existent or only weakly existent in the individual building blocks. Constructing 1D chains, 2D arrays and 3D superlattices using nanoparticles and colloids therefore continues to be one of the grand goals in colloid and nanomaterial science. Amongst these higher order structures, 1D colloidal chains are of particular interest, as they possess unique anisotropic properties. In recent years, the most relevant advances in 1D colloidal chain research have been made in novel synthetic methodologies and applications. In this review, we first address a comprehensive description of the research progress concerning various synthetic strategies developed to construct 1D colloidal chains. Following this, we highlight the amplified and emergent properties of the resulting materials, originating from the assembly of the individual building blocks and their collective behavior, and discuss relevant applications in advanced materials. In the discussion of synthetic strategies, properties, and applications, particular attention will be paid to overarching concepts, fresh trends, and potential areas of future research. We believe that this comprehensive review will be a driver to guide the interdisciplinary field of 1D colloidal chains, where nanomaterial synthesis, self-assembly, physical property studies, and material applications meet, to a higher level, and open up new research opportunities at the interface of classical disciplines.

Nanotechnology-aided advancement in the combating of cancer metastasis

Cancer, especially when it has metastasized to different locations in the body, is notoriously difficult to treat. Metastatic cancer accounts for most cancer deaths and thus remains an enormous challenge. During the metastasis process, cancer cells negotiate a series of steps termed the “metastatic cascadeˮ that offer potential for developing anti-metastatic therapy strategies. Currently available conventional treatment and diagnostic methods addressing metastasis come with their own pitfalls and roadblocks. In this contribution, we comprehensively discuss the potential improvements that nanotechnology-aided approaches are able to bring, either alone or in combination with the existing conventional techniques, to the identification and treatment of metastatic disease. We tie specific nanotechnology-aided strategies to the complex biology of the different steps of the metastatic cascade in order to open up new avenues for fine-tuned targeting and development of anti-metastatic agents designed specifically to prevent or mitigate the metastatic outgrowth of cancer. We also present a viewpoint on the progress of translation of nanotechnology into cancer metastasis patient care.

Comparison of the uptake of untargeted and targeted immunostimulatory nanoparticles by immune cells in the microenvironment of metastatic breast cancer

To alter the immunosuppressive tumor microenvironment (TME), we developed an immunostimulatory nanoparticle (NP) to reprogram a tumor's dysfunctional and inhibitory antigen-presenting cells (APCs) into properly activated APCs that stimulate tumor-reactive cytotoxic T cells. Importantly, systemic delivery allowed NPs to efficiently utilize the entire microvasculature and gain access into the majority of the perivascular TME, which coincided with the APC-rich tumor areas leading to uptake of the NPs predominantly by APCs. In this work, a 60 nm NP was loaded with a STING agonist, which triggered robust production of interferon β, resulting in activation of APCs. In addition to untargeted NPs, we employed 'mainstream' ligands targeting fibronectin, αvβ3 integrin and P-selectin that are commonly used to direct nanoparticles to tumors. Using the 4T1 mouse model, we assessed the microdistribution of the four NP variants in the tumor immune microenvironment in three different breast cancer landscapes, including primary tumor, early metastasis, and late metastasis. The different NP variants resulted in variable uptake by immune cell subsets depending on the organ and tumor stage. Among the NP variants, therapeutic studies indicated that the untargeted NPs and the integrin-targeting NPs exhibited a remarkable short- and long-term immune response and long-lasting antitumor effect.

SHMT1 siRNA-Loaded hyperosmotic nanochains for blood-brain/tumor barrier post-transmigration therapy

The near-perivascular accumulation in solid tumors and short-lived span in circulation, derails even the most competent nanoparticles (NPs) from achieving their maximum therapeutic potential. Moreover, delivering them across the blood brain/tumor barrier (BBB/BTB) is further challenging to sought anticancer effect. To address these key challenges, we designed a linearly aligned nucleic acid-complexed polydixylitol-based polymeric nanochains (X-NCs), with inherent hyperosmotic properties enabling transmigration of the BBB/BTB and navigation through deeper regions of the brain tumor. The high aspect ratio adds shape-dependent functional aspects to parent particles by providing effective payload increment and nuclear factor of activated T cells-5 (NFAT5)-mediated cellular uptake. Therefore, serine hydroxymethyltransferase 1 (SHMT1) siRNA-loaded nanochains not only demonstrated to transmigrate the BTB, but also resulted in remarkably reducing the tumor size to 97% in the glioblastoma xenograft brain tumor mouse models. Our study illustrates how the hyperosmotic nanochains with high aspect ratio and aligned structure can accelerate a therapeutic effect in aggressive brain tumors post-transmigration of the BBB/BTB by utilizing an NFAT5 mode of uptake mechanism.

Hyperthermia-mediated changes in the tumor immune microenvironment using iron oxide nanoparticles

Iron oxide nanoparticles (IONPs) have often been investigated for tumor hyperthermia. IONPs act as heating foci in the presence of an alternating magnetic field (AMF). It has been shown that hyperthermia can significantly alter the tumor immune microenvironment. Typically, mild hyperthermia invokes morphological changes within the tumor, which elicits a secretion of inflammatory cytokines and tumor neoantigens. Here, we focused on the direct effect of IONP-induced hyperthermia on the various tumor-resident immune cell subpopulations. We compared direct intratumoral injection to systemic administration of IONPs followed by application of an external AMF. We used the orthotopic 4T1 mouse model, which represents aggressive and metastatic breast cancer with a highly immunosuppressive microenvironment. A non-inflamed and 'cold' microenvironment inhibits peripheral effector lymphocytes from effectively trafficking into the tumor. Using intratumoral or systemic injection, IONP-induced hyperthermia achieved a significant reduction of all the immune cell subpopulations in the tumor. However, the systemic delivery approach achieved superior outcomes, resulting in substantial reductions in the populations of both innate and adaptive immune cells. Upon depletion of the existing dysfunctional tumor-resident immune cells, subsequent treatment with clinically approved immune checkpoint inhibitors encouraged the repopulation of the tumor with 'fresh' infiltrating innate and adaptive immune cells, resulting in a significant decrease of the tumor cell population.

Nanoprobe-Based Magnetic Resonance Imaging of Hypoxia Predicts Responses to Radiotherapy, Immunotherapy, and Sensitizing Treatments in Pancreatic Tumors

Accurate diagnosis of tumors and predicting the therapeutic responses are highly demanded in the clinic to improve the treatment efficacy and survival rates. Since hypoxia develops in the progression of tumors and inversely correlates with prognosis and promotes resistance to radiotherapies and immunotherapies, it is a potential marker for therapeutic prediction. Therefore, effective discrimination of tumor hypoxia for predicting therapeutic outcomes is critical. Here, a magnetic resonance imaging (MRI)-based diagnosis strategy using contrast-amplifying nanoprobes that sense tumor acidosis and real-time observation of hypoxic conditions in tumors has been developed, aiming at accurate detection of pancreatic tumors and prediction of therapeutic effects. Our approach selectively probed xenograft, allograft, and transgenic spontaneous models of intractable pancreatic cancer, which lacks standardized predictive markers to identify patients who benefit most from treatments, and effectively discriminated the intratumoral hypoxia levels. By stratification of pancreatic tumors based on quantitative MR imaging of hypoxia, it enabled prediction of the responses to radiotherapy and immune checkpoint inhibitors. Moreover, the nanoprobe-based MRI could monitor hypoxia reduction by tumor normalization treatments, which permits visualizing pancreatic tumors that will respond to immune checkpoint blockade therapy, enhancing the response rate. The results demonstrate the potential of our strategy for accurate tumor diagnosis, patient stratification, and effective therapy.

Tumor-Associated Fibroblast-Targeting Nanoparticles for Enhancing Solid Tumor Therapy: Progress and Challenges

Even though nanoparticle drug delivery systems (nanoDDSs) have improved antitumor efficacy by delivering more drugs to tumor sites compared to free and unencapsulated therapeutics, achieving satisfactory distribution and penetration of nanoDDSs inside solid tumors, especially in stromal fibrous tumors, remains challenging. As one of the most common stromal cells in solid tumors, tumor-associated fibroblasts (TAFs) not only promote tumor growth and metastasis but also reduce the drug delivery efficiency of nanoparticles through the tumor's inherent physical and physiological barriers. Thus, TAFs have been emerging as attractive targets, and TAF-targeting nanotherapeutics have been extensively explored to enhance the tumor delivery efficiency and efficacy of various anticancer agents. The purpose of this Review is to opportunely summarize the underlying mechanisms of TAFs on obstructing nanoparticle-mediated drug delivery into tumors and discuss the current advances of a plethora of nanotherapeutic approaches for effectively targeting TAFs.

Predicting Metastasis from Cues of Metastatic Cancer Stem-like Cells-3D-Ultrasensitive Metasensor at a Single-Cell Level

Metastasis is the primary reason for treatment failure and cancer-related deaths. Hence forecasting the disease in its primary state can advance the prognosis. However, existing techniques fail to reveal the tumor heterogeneity or its evolutionary cascades; hence they are not feasible to predict the onset of metastatic cancer. The key to metastasis originates from the primary tumor cells, evolving by inheriting multistep sequential cue signals. We have identified this specific population, termed metastatic cancer stem-like cells (MCSCs), to foresee cancer's ability to metastasize. An invasive property renders MCSCs nonadherent, summoning a powerful technique to forecast metastasis. Thus, we have generated an ultrasensitive 3D-metasensor to efficiently capture and investigate MCSCs and magnify the vital premetastatic signals from a single cell. We developed 3D-metasensor by an ultrafast laser ionization technique, consisting of self-assembled three-dimensionally organized nanoprobes incorporated with dopant functionalities. This distinct methodology establishes attachment with nonadherent MCSCs, elevates Raman activity, and enables probing of consequent signals (metabolic, proliferation, and metastatic) specifically altered in MCSCs. Extensive analysis using prediction tools-the area under the curve (AUC) and principal component analysis (PCA)-revealed high sensitivity (100%) and specificity (80%) to differentiate the MCSCs from other populations. Further, investigation reveals that the cue signal level from MCSCs of primary cancer is analogous to MCSCs from higher-level tumors, disclosing the relative dependence to estimate the primary tumor's capacity to metastasize. Multiple spectrum evaluation using the metasensor pinpoint the dynamic cues in MCSCs predict the onset of metastasis; thus, exploring these metastasis hallmarks can enhance prognosis and revolutionize therapy strategies.

Drug Resistance in Metastatic Breast Cancer: Tumor Targeted Nanomedicine to the Rescue

Breast cancer, specifically metastatic breast, is a leading cause of morbidity and mortality in women. This is mainly due to relapse and reoccurrence of tumor. The primary reason for cancer relapse is the development of multidrug resistance (MDR) hampering the treatment and prognosis. MDR can occur due to a multitude of molecular events, including increased expression of efflux transporters such as P-gp, BCRP, or MRP1; epithelial to mesenchymal transition; and resistance development in breast cancer stem cells. Excessive dose dumping in chemotherapy can cause intrinsic anti-cancer MDR to appear prior to chemotherapy and after the treatment. Hence, novel targeted nanomedicines encapsulating chemotherapeutics and gene therapy products may assist to overcome cancer drug resistance. Targeted nanomedicines offer innovative strategies to overcome the limitations of conventional chemotherapy while permitting enhanced selectivity to cancer cells. Targeted nanotheranostics permit targeted drug release, precise breast cancer diagnosis, and importantly, the ability to overcome MDR. The article discusses various nanomedicines designed to selectively target breast cancer, triple negative breast cancer, and breast cancer stem cells. In addition, the review discusses recent approaches, including combination nanoparticles (NPs), theranostic NPs, and stimuli sensitive or “smart” NPs. Recent innovations in microRNA NPs and personalized medicine NPs are also discussed. Future perspective research for complex targeted and multi-stage responsive nanomedicines for metastatic breast cancer is discussed.

Engineering nanoparticles to tackle tumor barriers

Engineering nanoparticles (NPs) as delivery systems of anticancer therapeutics has attracted tremendous attention in recent decades, and some nanoscale drug formulations have been approved for clinical use. However, their therapeutic efficacies are still limited by the presence of a series of biological barriers during the delivery process. Among these obstacles, tumor barriers are generally recognized as the bottleneck, because they dominate the NP extravasation from the tumor vasculature and penetration into the tumor parenchyma. Therefore, this review first discussed tumor barriers from two aspects: tumor vascular barriers and tumor stromal barriers. Pathological features of the two sets of barriers as well as their influence on the delivery efficacy were described. Then, we outlined strategies for engineering NPs to overcome these challenges: increasing extravasation through physical property optimization and tumor vascular targeting; and facilitating deep penetration through particle size manipulation, modulation of the tumor extracellular matrix, and some new mechanisms. This review will provide a critical perspective on engineering strategies for more efficient nanomedicine in oncology.

Stimuli-Responsive Iron Oxide Nanotheranostics: A Versatile and Powerful Approach for Cancer Therapy

Recent advancements in unravelling elements of cancer biology involved in disease progression and treatment resistance have highlighted the need for a holistic approach to effectively tackle cancer. Stimuli-responsive nanotheranostics based on iron oxide nanoparticles are an emerging class of versatile nanomedicines with powerful capabilities to "seek, sense, and attack" multiple components of solid tumors. In this work, the rationale for using iron oxide nanoparticles and the basic physical principles that impact their function in biomedical applications are reviewed. Subsequently, recent advances in the integration of iron oxide nanoparticles with various stimulus mechanisms to facilitate the development of stimuli-responsive nanotheranostics for application in cancer therapy are summarized. The integration of an iron oxide core with various surface coating mechanisms results in the generation of hybrid nanoconstructs with capabilities to codeliver a wide variety of highly potent anticancer therapeutics and immune modulators. Finally, emerging future directions and considerations for their clinical translation are touched upon.

The dance of the nanobubbles: detecting acoustic backscatter from sub-micron bubbles using ultra-high frequency acoustic microscopy

Nanobubbles have gained attention for their use as highly stable ultrasound (US) contrast agents, but assessment of individual nanobubble size remains a challenge. Current sizing techniques require either extensive sample preparation or depend on assumed values of nanobubble density that are not well characterized. An US based approach would be desirable; however, probing individual nanobubbles using US transducers at clinical frequencies is not feasible due to the comparatively long acoustic wavelengths employed. Here we present a technique which can be used to estimate nano- or microbubble size by virtue of the amount of motion detected in an M-Mode image acquired using an acoustic microscope equipped with a 200 MHz transducer. A sample of a bubble-containing solution is incorporated into a phantom composed of molten agarose. The solidified agarose gel contains pores with well-defined sizes dictated by the agarose concentration. Bubbles in the gel matrix that are smaller in diameter than the gel pore size are capable of undergoing stochastic motion which manifests as intensity fluctuations in M-Mode images. Conversely, bubbles which are larger than the agarose pores become trapped and produce static M-Mode intensity patterns. In this study, agarose gels with concentrations ranging from 0.25% to 1.25% (mean pore sizes ranging from 2.68 μm to 0.34 μm) were loaded with either nanobubbles (mean diameter 0.326 μm) or microbubbles (mean diameter 2.71 μm) and imaged at 200 MHz. In the nanobubble loaded gels, M-Mode fluctuations were clearly visible up to a gel concentration of 1% (pore size of 0.39 μm). In contrast, the microbubble loaded gels exhibited minimal M-Mode fluctuation even at agarose concentrations of 0.25% (2.68 μm pore size). Autocorrelation curves generated from the M-Mode data demonstrated a clear trend of curve flattening (loss of motion) when the pore size was comparable to mean bubble diameter, indicating that individual bubbles trapped in the agarose pores are the main source of acoustic backscatter. In the future, decay parameters extracted from the autocorrelation curves could potentially be used as indicators of mean bubble diameter for bubble populations of unknown size.

Two-Stage Assembly of Mesocrystal Fibers with Tunable Diameters in Weak Magnetic Fields

Controlling the morphology and crystallographic coherence of assemblies of magnetic nanoparticles is a promising route to functional materials. Time-resolved small-angle X-ray scattering (SAXS) was combined with microscopy and scaling analysis to probe and analyze evaporation-induced assembly in levitating drops and thin films of superparamagnetic iron oxide nanocubes in weak magnetic fields. We show that assembly of micrometer-sized mesocrystals with a cubic shape preceded the formation of fibers with a high degree of crystallographic coherence and tunable diameters. The second-stage assembly of aligned cuboidal mesocrystals into fibers was driven by the magnetic field, but the first-stage assembly of the oleate-capped nanocubes was unaffected by weak magnetic fields. The transition from 3D growth of the primary mesocrystals to the second stage 1D assembly of the elongated fibers was related to the size and field dependence of isotropic van der Waals and directional dipolar interactions between the interacting mesocrystals.

Chronic neural activity recorded within breast tumors

Nerve fibers are known to reside within malignant tumors and the greater the neuronal density the worse prognosis for the patient. Recent discoveries using tumor bearing animal models have eluded to the autonomic nervous system having a direct effect on tumor growth and metastasis. We report the first direct and chronic in vivo measurements of neural activity within tumors. Using a triple-negative mammary cancer mouse model and chronic neural interface techniques, we have recorded neural activity directly within the tumor mass while the tumor grows and metastasizes. The results indicate that there is a strong connection between the autonomic nervous system and the tumor and could help uncover the mechanisms of tumor growth and metastasis.

Recent advances in improving tumor-targeted delivery of imaging nanoprobes

Tumor-targeted delivery of imaging nanoprobes provides a promising approach for the precision imaging diagnosis of cancers. Nanoprobes with desired bio-nano interface properties can preferably enter tumor tissues through the vascular endothelium, penetrate into deep tissues, and detect target lesions. Surface engineering of nanoparticles offers a critical strategy to improve tumor-targeting capacities of nanoprobes. Improvements to the efficacy of targeted nanoprobes have been intensively explored and much of this work centers on the selection of suitable targeting ligands. Herein, in this review, various recent strategies based on different targeting ligands to improve tumor-targeting of imaging nanoprobes have been developed, ranging from small molecule ligands to biomimetic coatings, with highlights on emerging coating techniques using cell membranes and dual-targeting ligands. In particular, construction and surface modification methods, targeting capacities, and imaging/theranostic performance with key issues and potential questions have been described and discussed together with considerations for future development and innovations.

Molecular insights and novel approaches for targeting tumor metastasis

In recent years, due to the effective drug delivery and preciseness of tumor sites or microenvironment, the targeted drug delivery approaches have gained ample attention for tumor metastasis therapy. The conventional treatment approaches for metastasis therapy have reported with immense adverse effects because they exhibited maximum probability of killing the carcinogenic cells along with healthy cells. The tumor vasculature, comprising of vasculogenic impressions and angiogenesis, greatly depends upon the growth and metastasis in the tumors. Therefore, various nanocarriers-based delivery approaches for targeting to tumor vasculature have been attempted as efficient and potential approaches for the treatment of tumor metastasis and the associated lesions. Furthermore, the targeted drug delivery approaches have found to be most apt way to overcome from all the limitations and adverse effects associated with the conventional therapies. In this review, various approaches for efficient targeting of pharmacologically active chemotherapeutics against tumor metastasis with the cohesive objectives of prognosis, tracking and therapy are summarized.

Macrophage-cancer hybrid membrane-coated nanoparticles for targeting lung metastasis in breast cancer therapy

Cell membrane- covered drug-delivery nanoplatforms have been garnering attention because of their enhanced bio-interfacing capabilities that originate from source cells. In this top-down technique, nanoparticles (NPs) are covered by various membrane coatings, including membranes from specialized cells or hybrid membranes that combine the capacities of different types of cell membranes. Here, hybrid membrane-coated doxorubicin (Dox)-loaded poly(lactic-co-glycolic acid) (PLGA) NPs (DPLGA@[RAW-4T1] NPs) were fabricated by fusing membrane components derived from RAW264.7(RAW) and 4T1 cells (4T1). These NPs were used to treat lung metastases originating from breast cancer. This study indicates that the coupling of NPs with a hybrid membrane derived from macrophage and cancer cells has several advantages, such as the tendency to accumulate at sites of inflammation, ability to target specific metastasis, homogenous tumor targeting abilities in vitro, and markedly enhanced multi-target capability in a lung metastasis model in vivo. The DPLGA@[RAW-4T1] NPs exhibited excellent chemotherapeutic potential with approximately 88.9% anti-metastasis efficacy following treatment of breast cancer-derived lung metastases. These NPs were robust and displayed the multi-targeting abilities of hybrid membranes. This study provides a promising biomimetic nanoplatform for effective treatment of breast cancer metastasis.

Multifunctional nanoparticles as photosensitizer delivery carriers for enhanced photodynamic cancer therapy

Photodynamic therapy (PDT) is an emerging cancer treatment combining light, oxygen, and a photosensitizer (PS) to produce highly cytotoxic reactive oxygen species that cause cancer cell death. However, most PSs are hydrophobic molecules that have poor water solubility and cannot target tumor tissues, causing damage to normal tissues and cells during PDT. Thus, there is a substantial demand for the development of nanocarrier systems to achieve targeted delivery of PSs into tumor tissues and cells. This review summarizes the research progress in PS delivery systems for PDT treatment of tumors and focuses on the recent design and development of multifunctional nanoparticles as PS delivery carriers for enhanced PDT. These multifunctional nanoparticles possess unique properties, including tunable particle size, changeable shape, stimuli-responsive PS activation, controlled PS release, and hierarchical targeting capability. These properties can increase tumor accumulation, penetration, and cellular internalization of nanoparticles to achieve PS activation and/or release in cancer cells for enhanced PDT. Finally, recent developments in multifunctional nanoparticles for tumor-targeted PS delivery and their future prospects in PDT are discussed.

PTPmu-targeted nanoparticles label invasive pediatric and adult glioblastoma

Poor prognosis for glioblastoma (GBM) is a consequence of the aggressive and infiltrative nature of gliomas where individual cells migrate away from the main tumor to distant sites, making complete surgical resection and treatment difficult. In this manuscript, we characterize an invasive pediatric glioma model and determine if nanoparticles linked to a peptide recognizing the GBM tumor biomarker PTPmu can specifically target both the main tumor and invasive cancer cells in adult and pediatric glioma models. Using both iron and lipid-based nanoparticles, we demonstrate by magnetic resonance imaging, optical imaging, histology, and iron quantification that PTPmu-targeted nanoparticles effectively label adult gliomas. Using PTPmu-targeted nanoparticles in a newly characterized orthotopic pediatric SJ-GBM2 model, we demonstrate individual tumor cell labeling both within the solid tumor margins and at invasive and dispersive sites.

Ligand-Installed Nanocarriers toward Precision Therapy

Development of drug-delivery systems that selectively target neoplastic cells has been a major goal of nanomedicine. One major strategy for achieving this milestone is to install ligands on the surface of nanocarriers to enhance delivery to target tissues, as well as to enhance internalization of nanocarriers by target cells, which improves accuracy, efficacy, and ultimately enhances patient outcomes. Herein, recent advances regarding the development of ligand-installed nanocarriers are introduced and the effect of their design on biological performance is discussed. Besides academic achievements, progress on ligand-installed nanocarriers in clinical trials is presented, along with the challenges faced by these formulations. Lastly, the future perspectives of ligand-installed nanocarriers are discussed, with particular emphasis on their potential for emerging precision therapies.

Targeting Integrins in Cancer Nanomedicine: Applications in Cancer Diagnosis and Therapy

Due to advancements in nanotechnology, the application of nanosized materials (nanomaterials) in cancer diagnostics and therapeutics has become a leading area in cancer research. The decoration of nanomaterial surfaces with biological ligands is a major strategy for directing the actions of nanomaterials specifically to cancer cells. These ligands can bind to specific receptors on the cell surface and enable nanomaterials to actively target cancer cells. Integrins are one of the cell surface receptors that regulate the communication between cells and their microenvironment. Several integrins are overexpressed in many types of cancer cells and the tumor microvasculature and function in the mediation of various cellular events. Therefore, the surface modification of nanomaterials with integrin-specific ligands not only increases their binding affinity to cancer cells but also enhances the cellular uptake of nanomaterials through the intracellular trafficking of integrins. Moreover, the integrin-specific ligands themselves interfere with cancer migration and invasion by interacting with integrins, and this finding provides a novel direction for new treatment approaches in cancer nanomedicine. This article reviews the integrin-specific ligands that have been used in cancer nanomedicine and provides an overview of the recent progress in cancer diagnostics and therapeutic strategies involving the use of integrin-targeted nanomaterials.

Recent advances in nanotheranostics for triple negative breast cancer treatment

Triple-negative breast cancer (TNBC) is the most complex and aggressive type of breast cancer encountered world widely in women. Absence of hormonal receptors on breast cancer cells necessitates the chemotherapy as the only treatment regime. High propensity to metastasize and relapse in addition to poor prognosis and survival motivated the oncologist, nano-medical scientist to develop novel and efficient nanotherapies to solve such a big TNBC challenge. Recently, the focus for enhanced availability, targeted cellular uptake with minimal toxicity is achieved by nano-carriers. These smart nano-carriers carrying all the necessary arsenals (drugs, tracking probe, and ligand) designed in such a way that specifically targets the TNBC cells at site. Articulating the targeted delivery system with multifunctional molecules for high specificity, tracking, diagnosis, and treatment emerged as theranostic approach. In this review, in addition to classical treatment modalities, recent advances in nanotheranostics for early and effective diagnostic and treatment is discussed. This review highlighted the recently FDA approved immunotherapy and all the ongoing clinical trials for TNBC, in addition to nanoparticle assisted immunotherapy. Futuristic but realistic advancements in artificial intelligence (AI) and machine learning not only improve early diagnosis but also assist clinicians for their workup in TNBC. The novel concept of Nanoparticles induced endothelial leakiness (NanoEL) as a way of tumor invasion is also discussed in addition to classical EPR effect. This review intends to provide basic insight and understanding of the novel nano-therapeutic modalities in TNBC diagnosis and treatment and to sensitize the readers for continue designing the novel nanomedicine. This is the first time that designing nanoparticles with stoichiometric definable number of antibodies per nanoparticle now represents the next level of precision by design in nanomedicine.

Anisotropic nanomaterials for shape-dependent physicochemical and biomedical applications

This review contributes towards a systematic understanding of the mechanism of shape-dependent effects on nanoparticles (NPs) for elaborating and predicting their properties and applications based on the past two decades of research. Recently, the significance of shape-dependent physical chemistry and biomedicine has drawn ever increasing attention. While there has been a great deal of effort to utilize NPs with different morphologies in these fields, so far research studies are largely localized in particular materials, synthetic methods, or biomedical applications, and have ignored the interactional and interdependent relationships of these areas. This review is a comprehensive description of the NP shapes from theory, synthesis, property to application. We figure out the roles that shape plays in the properties of different kinds of nanomaterials together with physicochemical and biomedical applications. Through systematic elaboration of these shape-dependent impacts, better utilization of nanomaterials with diverse morphologies would be realized and definite strategies would be expected for breakthroughs in these fields. In addition, we have proposed some critical challenges and open problems that need to be addressed in nanotechnology.

Strong dependence of the nano-bio interactions on core morphology and layer composition of ultrasmall nanostructures

The interactions between nanoparticles (NPs) and proteins, cells, and tissues, broadly known as nano-bio interactions, depend on the NP size and shape and on the characteristics of the NP coating layer, such as density, thickness, and chemical makeup. The dependence of nano-membrane interactions on the design parameters of ultrasmall nanostructures is studied by computer simulations. Considered here are spheres, plates, rings, rods, tubes, and helices made up of either bare magnetite or passivated gold, interacting with charged or zwitterionic membranes. The analysis reveals a strong dependence on shape, size, and layer composition of various quantities that characterize the nano-bio behavior, including binding modes and affinities. This sensitivity can be exploited to design nanostructures that bind preferentially to membranes or that stabilize or disrupt membrane structural integrity. The method used here is general and not limited to the ultrasmall regime, so it can be adopted to study other nano-bio interactions systematically. The implications for the distribution of NPs in cells and tissues (biodistribution) and for passive and active transmembrane transport are discussed, both important processes in biomedicine.

Effective treatment of cancer metastasis using a dual-ligand nanoparticle

Metastasis is responsible for the majority of deaths of breast cancer patients. While cytotoxic drugs are available with high potency to kill breast cancer cells, they are not designed to specifically seek and navigate in the dynamic and continuously changing microenvironment of metastatic disease. To effectively delivery chemotherapeutic agents to metastasis, we designed a dual-ligand nanoparticle loaded with doxorubicin by using two different types of ligands targeting EGFR and α_vβ₃ integrin. Metastatic cancer cells continuously change resulting in heterogeneity even across adjacent micrometastatic regions with variable expression of these targetable receptors. Using a mouse model of breast cancer metastasis, in vivo and ex vivo imaging showed that both EGFR and α_vβ₃ integrin-targeting were required to reliably direct the nanoparticle to metastasis and capture the spread and exact topology of the disease. Survival studies compared the anticancer efficacy of the standard drug, EGFR-targeting nanoparticle, α_vβ₃ integrin-targeting nanoparticle and the dual-ligand nanoparticle. While all the other treatments produced moderate therapeutic outcomes, treatment with the dual-ligand nanoparticle yielded significant improvement and event-free survival in a mouse model of breast cancer metastasis.

Highly Integrated Nanoplatform Based on an E-Selectin-Targeting Strategy for Metastatic Breast Cancer Treatment

Therapeutic goals for metastatic breast cancer, including shrinkage of established metastasis and suppression of movement of tumor cells, are often hard to achieve and remain the main obstacles restricting the antimetastatic efficacy of targeted drug delivery systems (TDDSs). Herein, we proposed an E-selectin-targeting nanoplatform for the systemic treatment of metastatic breast cancer. Versatile functions, including killing the circulating tumor cells, shrinking the established lesions, as well as inhibiting the movement of tumor cells, were integrated into doxorubicin-loaded sialic acid-dextran-octadecanoic acid (SDO) micelles (SDD). The prepared SDD micelles could not only inhibit lung and liver metastasis in the orthotopic 4T1 tumors model, but also decrease the metastatic lesions in the metastatic 4T1 cell model, resulting in 27.33% reduced number of metastatic nodules when compared to those without sialic acid modification. It was found that the good antimetastatic effect of SDD was only partially attributed to its ability on removing metastatic cells and metastases. Most importantly, the blank SDO micelles left in the lesion could further inhibit the cell migration and cell-cell binding. These results suggest that SA-driven TDDS has the potential for specific targeting and effective treatment of cancer metastasis.

Anti-angiogenic Therapy for Retinal Disease

Recent breakthroughs in our understanding of the molecular pathophysiology of retinal vascular disease have allowed us to specifically target pathological angiogenesis while minimizing damage to the neurosensory retina. This is perhaps best exemplified by the development of therapies targeting the potent angiogenic growth factor and vascular permeability mediator, vascular endothelial growth factor (VEGF). Anti-VEGF therapies, initially introduced for the treatment of choroidal neovascularization in patients with age-related macular degeneration, have also had a dramatic impact on the management of retinal vascular disease and are currently an indispensable component for the treatment of macular edema in patients with diabetic eye disease and retinal vein occlusions. Emerging evidence supports expanding the use of therapies targeting VEGF for the treatment of retinal neovascularization in patients with diabetic retinopathy and retinopathy of prematurity. However, VEGF is among a growing list of angiogenic and vascular hyperpermeability factors that promote retinal vascular disease. Many of these mediators are expressed in response to stabilization of a single family of transcription factors, the hypoxia-inducible factors (HIFs), that regulate the expression of these angiogenic stimulators. Here we review the basic principles driving pathological angiogenesis and discuss the current state of retinal anti-angiogenic pharmacotherapy as well as future directions.

Magnetic Resonance Imaging for Characterization of a Chick Embryo Model of Cancer Cell Metastases

Metastasis is the most common cause of death for patients with cancer. To fully understand the steps involved in metastatic dissemination, in vivo models are required, of which murine ones are the most common. Therefore, preclinical imaging methods such as magnetic resonance imaging (MRI) have mainly been developed for small mammals and their potential to monitor cancer growth and metastasis in nonmammalian models is not fully harnessed. We have here used MRI to measure primary neuroblastoma tumor size and metastasis in a chick embryo model. We compared its sensitivity and accuracy to end-point fluorescence detection upon dissection. Human neuroblastoma cells labeled with green fluorescent protein (GFP) and micron-sized iron particles were implanted on the extraembryonic chorioallantoic membrane of the chick at E7. T₂ RARE, T₂-weighted fast low angle shot (FLASH) as well as time-of-flight MR angiography imaging were applied at E14. Micron-sized iron particle labeling of neuroblastoma cells allowed in ovo observation of the primary tumor and tumor volume measurement noninvasively. Moreover, T₂ weighted and FLASH imaging permitted the detection of small metastatic deposits in the chick embryo, thereby reinforcing the potential of this convenient, 3R compliant, in vivo model for cancer research.

Nanotechnology in metastatic cancer treatment: Current Achievements and Future Research Trends

The systemic spread of malignant cells from a primary site, a process termed metastasis represents a global challenge in cancer treatment. There is a real need to develop novel therapy strategies and nanomedicine may have remarkable and valuable contribution through specific and selective delivery of chemotherapeutic agents, through its intrinsic cytotoxic activity or through imaging applications, appealing also in the context of cancer personalized therapy. This review is focused on the applications of nanoparticles in the treatment of metastatic cancer, particularly on the possible effect on cell stabilization, growth inhibition, eventual interaction with adhesion molecules and antiangiogenic effect.

Imaging breast cancer using a dual-ligand nanochain particle

Nanoparticles often only exploit the upregulation of a receptor on cancer cells to enhance intratumoral deposition of therapeutic and imaging agents. However, a single targeting moiety assumes that a tumor is homogenous and static. Tumoral microenvironments are both heterogenous and dynamic, often displaying variable spatial and temporal expression of targetable receptors throughout disease progression. Here, we evaluated the in vivo performance of an iron oxide nanoparticle in terms of targeting and imaging of orthotropic mouse models of aggressive breast tumors. The nanoparticle, a multi-component nanochain, was comprised of 3–5 iron oxide nanoparticles chemically linked in a linear chain. The nanoparticle’s surface was decorated with two types of ligands each targeting two different upregulated biomarkers on the tumor endothelium, P-selectin and fibronectin. The nanochain exhibited improved tumor deposition not only through vascular targeting but also through its elongated structure. A single-ligand nanochain exhibited a ~2.5-fold higher intratumoral deposition than a spherical nanoparticle variant. Furthermore, the dual-ligand nanochain exhibited higher consistency in generating detectable MR signals compared to a single-ligand nanochain. Using a 7T MRI, the dual-ligand nanochains exhibited highly detectable MR signal within 3h after injection in two different animal models of breast cancer.

How can nanotechnology help the fight against breast cancer?

In this review we provide a broad overview on the use of nanotechnology for the fight against breast cancer (BC). Nowadays, detection, diagnosis, treatment, and prevention may be possible thanks to the application of nanotechnology to clinical practice. Taking into consideration the different forms of BC and the disease status, nanomaterials can be designed to meet the most forefront objectives of modern therapy and diagnosis. We have analyzed in detail three main groups of nanomaterial applications for BC treatment and diagnosis. We have identified several types of drugs successfully conjugated with nanomaterials. We have analyzed the main important imaging techniques and all nanomaterials used to help the non-invasive, early detection of the lesions. Moreover, we have examined theranostic nanomaterials as unique tools, combining imaging, detection, and therapy for BC. This state of the art review provides a useful guide depicting how nanotechnology can be used to overcome the current barriers in BC clinical practice, and how it will shape the future scenario of treatments, prevention, and diagnosis, revolutionizing the current approaches, e.g., reducing the suffering related to chemotherapy.

Nanoparticle-Mediated Therapeutic Agent Delivery for Treating Metastatic Breast Cancer-Challenges and Opportunities

Breast cancer (BC) is the second leading cause of cancer-related death in American women and more than 90% of BC-related death is caused by metastatic BC (MBC). This review stresses the limited success of traditional therapies as well as the use of nanomedicine for treating MBC. Understanding the biological barriers of MBC that nanoparticle in vivo trafficking must overcome could provide valuable new insights for translating nanomedicine from the bench side to the bedside. A view about nanomedicine applied in BC therapy has been summarized with their present status, which is gaining attention in the clinically-applied landscape. The progressions of drug/gene delivery systems, especially the status of their preclinical or clinical trials, are also discussed. Here we highlight that the treatment of metastasis, in addition to the extensively described inhibition of primary tumor growth, is an indispensable requirement for nanomedicine. Along with more innovations in material chemistry and more progressions in biology, nanomedicine will constantly supply more exciting new approaches for targeted drug/gene delivery against MBC.

Latent Naphthalimide Bearing Water-Soluble Nanoprobes with Catechol-Fe(III) Cores for in Vivo Fluorescence Imaging of Intracellular Thiols

Here, a novel latent naphthalimide bearing water-soluble nanoprobes with catechol-Fe(III) cores (Fe@LNNPs) was designed, synthesized, and evaluated for in vivo fluorescence imaging of intracellular thiols, as various diseases are associated with overexpression of cellular biothiols. The Fe@LNNPs are mainly composed of three components. The inner part constitutes pyrocatechol groups, which can coordinate with Fe(III) to form a cross-linked core for improving the stability in the complex biological environment. The naphthalimide group is linked by disulfide with the core to quench the probe fluorescence. The outer part is designed to be a hydrophilic glycol corona for prolonging blood circulation. Also, a biotin group can be easily introduced into the nanoprobe for actively targeting the HepG2 cells. The fluorescence spectra reveals that the Fe@LNNPs can be reduced explicitly by glutathione to trigger the fluorescence emission. Confocal microscopic imagings and animal experiments manifest that the Fe@LNNPs, especially with biotin groups, have much better fluorescence signal imaging compared to the reported small-molecule probe 1' both in vitro and in vivo (up to 24 h). The Fe@LNNPs thus feature great advantages such as specificity, stability, biocompatibility, and long retention time for thiol-recognition imaging and hold potential applications in clinical cancer diagnosis.

Precise targeting of cancer metastasis using multi-ligand nanoparticles incorporating four different ligands

Metastasis displays a highly heterogeneous cellular population with cancer cells continuously evolving. As a result, a single-ligand nanoparticle cannot account for the continuously changing expression of targetable biomarkers over time and space. To effectively direct nanoparticles to metastasis, we developed a multi-ligand nanoparticle by using four different types of ligands on the same nanoparticle that target biomarkers on the endothelium associated with metastatic disease. These vascular targets included αvβ3 integrin, P-selectin, EGFR and fibronectin. Using terminal and in vivo imaging studies, the targeting performance of the multi-ligand nanoparticles was compared to the single-ligand nanoparticle variants. All four single-ligand nanoparticle variants achieved significant targeting of lung metastasis in the 4T1 mouse model of breast cancer metastasis with about 2.5% of the injected dose being deposited into metastasis. A dual-ligand nanoparticle resulted in a nearly 2-fold higher deposition into lung metastases than its single-ligand counterparts. The multi-ligand nanoparticle significantly outperformed its targeting nanoparticle counterparts achieving a deposition of ∼7% of its injected nanoparticles into lung metastases. Using the high sensitivity of radionuclide imaging, PET imaging showed that a multi-ligand nanoparticle labeled with [18F]fluoride was able to precisely target metastatic disease at its very early stage of development in three different animal models of metastatic breast cancer.

Review of quantitative multiscale imaging of breast cancer

Breast cancer is the most common cancer among women worldwide and ranks second in terms of overall cancer deaths. One of the difficulties associated with treating breast cancer is that it is a heterogeneous disease with variations in benign and pathologic tissue composition, which contributes to disease development, progression, and treatment response. Many of these phenotypes are uncharacterized and their presence is difficult to detect, in part due to the sparsity of methods to correlate information between the cellular microscale and the whole-breast macroscale. Quantitative multiscale imaging of the breast is an emerging field concerned with the development of imaging technology that can characterize anatomic, functional, and molecular information across different resolutions and fields of view. It involves a diverse collection of imaging modalities, which touch large sections of the breast imaging research community. Prospective studies have shown promising results, but there are several challenges, ranging from basic physics and engineering to data processing and quantification, that must be met to bring the field to maturity. This paper presents some of the challenges that investigators face, reviews currently used multiscale imaging methods for preclinical imaging, and discusses the potential of these methods for clinical breast imaging.