Bioinspired lipoproteins-mediated photothermia remodels tumor stroma to improve cancer cell accessibility of second nanoparticles

Nano drug delivery systems improve metastatic breast cancer therapy

Despite continual progress in the technologies and regimens for cancer therapy, the treatment outcome of fatal metastatic breast cancer is far from satisfactory. Encouragingly, nanotechnology has emerged as a valuable tool to optimize drug delivery process in cancer therapy via preventing the cargos from degradation, improving the tumor-targeting efficiency, enhancing therapeutic agents' retention in specific sites, and controlling drug release. In the last decade, several mechanisms of suppressing tumor metastasis by functional nano drug delivery systems (NDDSs) have been revealed and a guidance for the rational design of anti-metastasis NDDSs is summarized, which consist of three aspects: optimization of physiochemical properties, tumor microenvironment remodeling, and biomimetic strategies. A series of medicinal functional biomaterials and anti-metastatic breast cancer NDDSs constructed by our team are introduced in this review. It is hoped that better anti-metastasis strategies can be inspired and applied in clinic.

A combination strategy based on an Au nanorod/doxorubicin gel via mild photothermal therapy combined with antigen-capturing liposomes and anti-PD-L1 agent promote a positive shift in the cancer-immunity cycle

The antitumor immune response involves a cascade of cancer-immunity cycles. Developing a combination therapy aimed at the cancer-immunity cycle is of great importance. In this research, we designed and tested a combined therapeutic-Au nanorod (AuNR)/doxorubicin (DOX) gel (AuNR/DOX gel)-in which the sustained release of DOX was controlled by Pluronic gel. DOX served as an immunogenic tumor cell death (ICD) inducer, triggering the production of damage-associated molecular patterns (DAMPs). Mild photothermal therapy (Mild PTT) produced by 880 nm laser-irradiated AuNRs also generated tumor-associated antigens. Maleimide-modified liposomes (L-Mals), as antigen capturing agents, promoted tumor antigen uptake by DCs. Ultimately, more CD8+ T cells and fewer regulatory T cells (Tregs) infiltrated the tumor, eliciting antitumor responses from the PD-L1 antibody. Our results indicate that this combination strategy promotes a positive shift in the cancer-immunity cycle and holds much promise for combination strategy will lead to development of an antitumor drug delivery system. STATEMENT OF SIGNIFICANCE: Developing a combination therapy for cancer-immunity cycle is of great importance due to antitumor immune response involving a cascade of cancer-immunity cycles. Cancer-immunity cycle usually includes tumor antigen release, antigen presentation, immune activation, trafficking, infiltration, specific recognition of tumor cells by T cells, and finally cancer cell killing. In this research, we designed a combination strategy based on Au nanorod/doxorubicin gel via mild photothermal therapy combined with antigen-capturing liposomes and anti-PD-L1 agent promoting a positive shift in the cancer-immunity cycle. Our results indicate that this combination strategy promotes a positive shift in the cancer-immunity cycle and holds much promise for combination strategy will lead to development of an antitumor drug delivery system.

Tumor Microenvironment Modulating Functional Nanoparticles for Effective Cancer Treatments

Cancer is one of the major diseases that threaten human life worldwide. Despite advances in cancer treatment techniques, such as radiation therapy, chemotherapy, targeted therapy, and immunotherapy, it is still difficult to cure cancer because of the resistance mechanism of cancer cells. Current understanding of tumor biology has revealed that resistance to these anticancer therapies is due to the tumor microenvironment (TME) represented by hypoxia, acidity, dense extracellular matrix, and immunosuppression. This review demonstrates the latest strategies for effective cancer treatment using functional nanoparticles that can modulate the TME. Indeed, preclinical studies have shown that functional nanoparticles can effectively modulate the TME to treat refractory cancer. This strategy of using TMEs with controllable functional nanoparticles is expected to maximize cancer treatment efficiency in the future by combining it with various modern cancer therapeutics.

Unleashing the potential of cell membrane-based nanoparticles for COVID-19 treatment and vaccination

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a particular coronavirus strain responsible for the coronavirus disease 2019 (COVID-19), accounting for more than 3.1 million deaths worldwide. Several health-related strategies have been successfully developed to contain the rapidly-spreading virus across the globe, toward reduction of both disease burden and infection rates. Particularly, attention has been focused on either the development of novel drugs and vaccines, or by adapting already-existing drugs for COVID-19 treatment, mobilizing huge efforts to block disease progression and to overcome the shortage of effective measures available at this point.Areas covered: This perspective covers the breakthrough of multifunctional biomimetic cell membrane-based nanoparticles as next-generation nanosystems for cutting-edge COVID-19 therapeutics and vaccination, specifically cell membrane-derived nanovesicles and cell membrane-coated nanoparticles, both tailorable cell membrane-based nanosystems enriched with the surface repertoire of native cell membranes, toward maximized biointerfacing, immune evasion, cell targeting and cell-mimicking properties.Expert opinion: Nano-based approaches have received widespread interest regarding enhanced antigen delivery, prolonged blood circulation half-life and controlled release of drugs. Cell membrane-based nanoparticles comprise interesting antiviral multifunctional nanoplatforms for blocking SARS-CoV-2 binding to host cells, reducing inflammation through cytokine neutralization and improving drug delivery toward COVID-19 treatment.

Tackling TAMs for Cancer Immunotherapy: It's Nano Time

The tumor microenvironment (TME) is a highly complex environment that surrounds tumors. Interactions between cancer cells/non-cancerous cells and cells/non-cell components in the TME support tumor initiation, development, and metastasis. Of the cell types in the TME, tumor-associated macrophages (TAMs) have gained attention owing to their crucial roles in supporting tumors and conferring therapy resistance. Recent developments in nanotechnology raise opportunities for the application of nano targeted drug-delivery systems (Nano-TDDS) in cancer therapy. We focus our discussion on current knowledge of TAMs, and describe recent examples of Nano-TDDS-based TAM modulation, highlighting strategies to overcome in vivo delivery barriers associated with the TME and their potential for clinical translation.

Nanotechnology for Boosting Cancer Immunotherapy and Remodeling Tumor Microenvironment: The Horizons in Cancer Treatment

Immunotherapy that harnesses the human immune system to fight cancer has received widespread attention and become a mainstream strategy for cancer treatment. Cancer immunotherapy not only eliminates primary tumors but also treats metastasis and recurrence, representing a major advantage over traditional cancer treatments. Recently with the development of nanotechnology, there exists much work applying nanomaterials to cancer immunotherapy on the basis of their excellent physiochemical properties, such as efficient tissue-specific delivery function, huge specific surface area, and controllable surface chemistry. Consequently, nanotechnology holds significant potential in improving the efficacy of cancer immunotherapy. Nanotechnology-based immunotherapy mainly manifests its inhibitory effect on tumors via two different approaches: one is to produce an effective anti-tumor immune response during tumorigenesis, and the other is to enhance tumor immune defense ability by modulating the immune suppression mechanism in the tumor microenvironment. With the success of tumor immunotherapy, understanding the interaction between the immune system and smart nanomedicine has provided vigorous vitality for the development of cancer treatment. This review highlights the application, progress, and prospect of nanomedicine in the process of tumor immunoediting and also discusses several engineering methods to improve the efficiency of tumor treatment.

Bio-Nanocarriers for Lung Cancer Management: Befriending the Barriers

Lung cancer is a complex thoracic malignancy developing consequential to aberrations in a myriad of molecular and biomolecular signaling pathways. It is one of the most lethal forms of cancers accounting to almost 1.8 million new annual incidences, bearing overall mortality to incidence ratio of 0.87. The dismal prognostic scenario at advanced stages of the disease and metastatic/resistant tumor cell populations stresses the requisite of advanced translational interdisciplinary interventions such as bionanotechnology. This review article deliberates insights and apprehensions on the recent prologue of nanobioengineering and bionanotechnology as an approach for the clinical management of lung cancer. The role of nanobioengineered (bio-nano) tools like bio-nanocarriers and nanobiodevices in secondary prophylaxis, diagnosis, therapeutics, and theranostics for lung cancer management has been discussed. Bioengineered, bioinspired, and biomimetic bio-nanotools of considerate translational value have been reviewed. Perspectives on existent oncostrategies, their critical comparison with bio-nanocarriers, and issues hampering their clinical bench side to bed transformation have also been summarized.

Tumor microenvironment remodeling-based penetration strategies to amplify nanodrug accessibility to tumor parenchyma

Remarkable advances in nano delivery systems have provided new hope for tumor prevention, diagnosis and treatment. However, only limited clinical therapeutic effects against solid tumors were achieved. One of the main reasons is the presence of abundant physiological and pathological barriers in vivo that impair tumoral penetration and distribution of the nanodrugs. These barriers are related to the components of tumor microenvironment (TME) including abnormal tumor vasculature, rich composition of the extracellular matrix (ECM), and abundant stroma cells. Herein, we review the advanced strategies of TME remodeling to overcome these biological obstacles against nanodrug delivery. This review aims to offer a perspective guideline for the implementation of promising approaches to facilitate intratumoral permeation of nanodrugs through alleviation of biological barriers. At the same time, we analyze the advantages and disadvantages of the corresponding methods and put forward possible directions for the future researches.

Oxygen-Delivering Polyfluorocarbon Nanovehicles Improve Tumor Oxygenation and Potentiate Photodynamic-Mediated Antitumor Immunity

Hypoxia is a critical cause of tumor immunosuppression, and it significantly limits the efficacy of many anticancer modalities. Herein, we report an amphiphilic F₁₁-derivative-based oxygen-delivering polyfluorocarbon nanovehicle loading photodynamic DiIC₁₈(5) and reactive oxygen species (ROS)-sensitive prodrug of chemo-immunomodulatory gemcitabine (PF₁₁DG), aimed at relieving tumor hypoxia and boosting antitumor immunity for cancer therapy. We optimized F₁₁-based polyfluorocarbon nanovehicles with a 10-fold enhancement of tumor oxygenation. PF₁₁DG exhibited intriguing capabilities, such as oxygen-dissolving, ROS production, and responsive drug release. In tumors, PF₁₁DG exhibited flexible intratumoral permeation and boosted robust antitumor immune responses upon laser irradiation. Notably, the treatment of PF₁₁DG plus laser irradiation (PF₁₁DG+L) significantly retarded the tumor growth with an 82.96% inhibition in the 4T1 breast cancer model and a 93.6% inhibition in the PANC02 pancreatic cancer model with better therapeutic benefits than non-oxygen-delivering nanovehicles. Therefore, this study presents an encouraging polyfluorocarbon nanovehicle with deep tumor-penetrating and hypoxia-relieving capacity to boost antitumor immunity for cancer treatment.

Sequential Modulations of Tumor Vasculature and Stromal Barriers Augment the Active Targeting Efficacy of Antibody-Modified Nanophotosensitizer in Desmoplastic Ovarian Carcinoma

Active-targeted nanoparticles are attractive carriers due to their potentials to facilitate specific delivery of drugs into tumor cells while sparing normal cells. However, the therapeutic outcomes of active-targeted nanomedicines are hampered by the multiple physiological barriers in the tumor microenvironment (TME). Herein, an epidermal growth factor receptor-targeted ultra-pH-sensitive nanophotosensitizer is fabricated, and the regulation of the TME to augment the active targeting ability and therapeutic efficacy is pinpointed. The results reveal that tumor vasculature normalization with thalidomide indiscriminately enhance the tumor accumulation of passive and active targeted nanoparticles, both of which are sequestered in the stromal bed of tumor mass. Whereas, photoablation of stromal cells located in perivascular regions significantly improves the accessibility of antibody-modified nanophotosensitizer to receptor-overexpressed cancer cells. After sequential regulation of TME, the antitumor efficacy of antibody-modified nanophotosensitizer is drastically enhanced through synergistic enhancements of tumor accumulation and cancer cell accessibility of active-targeted nanoparticles. The study offers deep insights about the intratumoral barriers that hinder the active-targeted nanoparticles delivery, and provides a basis for developing more effective strategies to accelerate the clinical translation of active-targeted nanomedicines.

Harnessing Extracellular Matrix Biology for Tumor Drug Delivery

The extracellular matrix (ECM) plays an active role in cell life through a tightly controlled reciprocal relationship maintained by several fibrous proteins, enzymes, receptors, and other components. It is also highly involved in cancer progression. Because of its role in cancer etiology, the ECM holds opportunities for cancer therapy on several fronts. There are targets in the tumor-associated ECM at the level of signaling molecules, enzyme expression, protein structure, receptor interactions, and others. In particular, the ECM is implicated in invasiveness of tumors through its signaling interactions with cells. By capitalizing on the biology of the tumor microenvironment and the opportunities it presents for intervention, the ECM has been investigated as a therapeutic target, to facilitate drug delivery, and as a prognostic or diagnostic marker for tumor progression and therapeutic intervention. This review summarizes the tumor ECM biology as it relates to drug delivery with emphasis on design parameters targeting the ECM.

Dual-Responsive and Deep-Penetrating Nanomicelles for Tumor Therapy via Extracellular Matrix Degradation and Oxidative Stress

Tumor microenvironment (TME), with complex composition, plays a vital role in the occurrence, development, and metastasis of tumors. TME becomes an important obstacle to the accessibility of nanotherapy, thus indicating the need to improve the functional design to overcome this challenge. In this study, we generate an intelligent nano-drug-delivery system (DOX@PssP-Hh NPs) with dual environmental response, which involves heparanase (HPSE) in TME and glutathione (GSH) in tumor cells. The nanosystem consists of a nanoskeleton formed by self-assembly of mPEG-ss-PEI and α-CD (PssP), chemotherapy drug doxorubicin (DOX) for enhancing antitumor efficacy, together with hyaluronidase (HAase), which is designed to degrade extracellular matrix to increase drug penetration, and an outer shell of heparin. Through the process of "responsive disintegration-remodeling tumor microenvironment-enhancing drug penetration-inducing oxidative stress", the semi-rotaxaneself-assembled nanomicelles were constructed to achieve the progressive function. DOX@PssP-Hh NPs with the size of 81.85 ± 1.85 nm exhibited satisfactory cytotoxicity (IC₅₀ = 0.80 ± 0.33 μg/mL). With the disulfide bond-mediated GSH depletion and DOX-mediated reactive oxygen species (ROS) production, treatment with DOX@PssP-Hh NPs prominently reduced glutathione peroxidase 4 (GPX4) level and would lead to enhanced oxidative stresses. Hyaluronic acid (HA), collagen I, and α-smooth muscle actin (α-SMA) were significantly reduced for TME remodulation. Moreover, the antitumor effect in vivo implied that DOX@PssP-Hh NPs could inhibit tumor growth effectively and reduce tumor interstitial fluid pressure (IFP) evidently. In conclusion, DOX@PssP-Hh NPs improved the penetration of drugs and exhibited enhanced antitumor efficacy.

Designing Nanoparticle-based Drug Delivery Systems for Precision Medicine

Traditional drugs are facing bottlenecks of lower solubility, absorption, and especially the inefficient organs or cells targeting during the precision medicine era. It is urgently needed to discover and establish new methods or strategies to modify old drugs or create new ones against the above defects. With the support of nanotechnology, the solubility, absorption and targeting of traditional drugs were greatly improved by modifying and fabricating with various types of nanoparticles to some extent, though many shortages remain. In this mini-review we will focus on advances in several most commonly used nanoparticles, from their nature and design, to drug delivery system and clinical application, that they overcome heterogeneous barriers in precision medicine, thereby ultimately improve patient outcome overall.

Albumin-based fluorescence resonance energy transfer nanoprobes for multileveled tumor tissue imaging and dye release imaging

Tumor tissue imaging and drug release imaging are both crucial for tumor imaging and image-guided drug delivery. It is urgent to develop a multileveled tumor imaging platform to realize the multiple imaging applications. In this work, we synthesized an albumin-based fluorescence resonance energy transfer (FRET) probe Cy5/7@HSA NPs containing two near-infrared cyanine dyes (CyBI5 and CyBI7) with high FRET efficiency (97 %). Excellent brightness and efficient FRET inside Cy5/7@HSA NPs enabled high-sensitive cell imaging and tumor imaging. This unique nanoprobe imaged 4T1 tumor-bearing mice with high sensitivity (TBR = 5.2) at 24 h post-injection and the dyes penetrated the tumor interior around 4 h post-injection. The release of dyes from nanoprobes was also tracked. This result shows the strong potential of this albumin-based FRET nanoprobe as multileveled tumor imaging platform for in vivo tumor imaging, drug delivery and image-guided surgery.

Tumor-permeated bioinspired theranostic nanovehicle remodels tumor immunosuppression for cancer therapy

The robust immunosuppressive microenvironment in tumor represents a key challenge of cancer treatment, and their modulations by versatile therapeutic agents are critically hampered by the limited intratumoral delivery. Herein, we report a bioinspired tumor-responsive theranostic nanovehicle (BTN) with striking tumor-penetrating capability to relieve the profound immunosuppression in tumor for effective cancer therapy. BTN is designed by loading tumor-activated melittin pro-peptide, theranostic photochlor and reactive oxygen species (ROS)-responsive prodrug of chemo-immunomodulator gemcitabine into a bioinspired lipoprotein-based nanovehicle, which display prominent tumor accumulation and flexible intratumoral permeation. Notably, the BTN-mediated combinational treatment caused drastic elimination of multiple immunosuppressive cells and remarkable infiltration of cytotoxic lymphocytes in tumor, thereby essentially relieving the tumor immunosuppression and strikingly depressing the tumor growth. Therefore, this design provides an encouraging delivery nanoplatform with distinguished immunosuppression-relieving capacity for effective cancer therapy.

Her2-Targeted Multifunctional Nano-Theranostic Platform Mediates Tumor Microenvironment Remodeling and Immune Activation for Breast Cancer Treatment

Purpose

The treatment of breast cancer is often ineffective due to the protection of the tumor microenvironment and the low immunogenicity of tumor cells, leading to a poor therapeutic effect. In this study, we designed a nano-theranostic platform for these obstacles: a photothermal effect mediated by a gold shell could remodel the tumor microenvironment by decreasing cancer-associated fibroblasts (CAFs) and promote the release of doxorubicin (DOX) from nanoparticles. In addition, it could realize photoacoustic (PA)/MRI dual-model imaging for diagnose breast cancer and targeted identification of Her2-positive breast cancer.

Methods

Her2-DOX-superparamagnetic iron oxide nanoparticles (SPIOs)@Poly (D, L-lactide-co-glycolide) acid (PLGA)@Au nanoparticles (Her2-DSG NPs) were prepared based on a single emulsion oil-in-water (O/W) solvent evaporation method, gold seed growing method, and carbon diimide method. The size distribution, morphology, PA/MRI imaging, drug loading capacity, and drug release were investigated. Cytotoxicity, antitumor effect, cellular uptake, immunogenic cell death (ICD) effect, and targeted performance on human Her2-positive BT474 cell line were investigated in vitro. BT474/Adr cells were constructed and the antitumor effect of NPs on it was evaluated in vitro. Moreover, chemical-photothermal therapy effect, PA/MRI dual-model imaging, ICD effect induced by NPs, and tumor microenvironment remodeling in human BT474 breast cancer nude mice model were also investigated.

Results

Nanoparticles were spherical, uniform in size and covered with a gold shell. NPs had a photothermal effect, and can realize photothermal-controlled drug release in vitro. Chemical-photothermal therapy had a good antitumor effect on BT474/Adr cells and on BT474 cells in vitro. The targeting evaluation in vitro showed that Her2-DSG NPs could actively target and identify Her2-positive tumor cells. The PA/MRI imaging was successfully validated in vitro/vivo. Similarly, NPs could enhance the ICD effect in vitro/vivo, which could activate an immune response. Immunofluorescence results also proved that photothermal effect could decrease CAFs to remodel the tumor microenvironment and enhance the accessibility of NPs to tumor cells. According to the toxicity results, targeted drug delivery combined with photothermal-responsive drug release proved that NPs had good biosafety in vivo. Chemical-photothermal therapy of Her2-targeted NPs has a good antitumor effect in the BT474 nude mice model.

Conclusion

Our study showed that chemical-photothermal therapy combined with tumor microenvironment remodeling and immune activation based on the Her2-DSG NPs we developed are very promising for Her2-positive breast cancer.

Engineering precision nanoparticles for drug delivery

In recent years, the development of nanoparticles has expanded into a broad range of clinical applications. Nanoparticles have been developed to overcome the limitations of free therapeutics and navigate biological barriers — systemic, microenvironmental and cellular — that are heterogeneous across patient populations and diseases. Overcoming this patient heterogeneity has also been accomplished through precision therapeutics, in which personalized interventions have enhanced therapeutic efficacy. However, nanoparticle development continues to focus on optimizing delivery platforms with a one-size-fits-all solution. As lipid-based, polymeric and inorganic nanoparticles are engineered in increasingly specified ways, they can begin to be optimized for drug delivery in a more personalized manner, entering the era of precision medicine. In this Review, we discuss advanced nanoparticle designs utilized in both non-personalized and precision applications that could be applied to improve precision therapies. We focus on advances in nanoparticle design that overcome heterogeneous barriers to delivery, arguing that intelligent nanoparticle design can improve efficacy in general delivery applications while enabling tailored designs for precision applications, thereby ultimately improving patient outcome overall.

Advances in nanoparticle design could make substantial contributions to personalized and non-personalized medicine. In this Review, Langer, Mitchell, Peppas and colleagues discuss advances in nanoparticle design that overcome heterogeneous barriers to delivery, as well as the challenges in translating these design improvements into personalized medicine approaches.

Phospholipid membrane-decorated deep-penetrated nanocatalase relieve tumor hypoxia to enhance chemo-photodynamic therapy

Hypoxia is a serious impediment to current treatments of many malignant tumors. Catalase, an antioxidant enzyme, is capable of decomposing endogenous hydrogen peroxide (H₂O₂) into oxygen for tumor reoxygenation, but suffered from in vivo instability and limited delivery to deep interior hypoxic regions in tumor. Herein, a deep-penetrated nanocatalase-loading DiIC₁₈ (5, DiD) and soravtansine (Cat@PDS) were provided by coating catalase nanoparticles with PEGylated phospholipids membrane, stimulating the structure and function of erythrocytes to relieve tumor hypoxia for enhanced chemo-photodynamic therapy. After intravenous administration, Cat@PDS preferentially accumulated at tumor sites, flexibly penetrated into the interior regions of tumor mass and remarkably relieved the hypoxic status in tumor. Notably, the Cat@PDS + laser treatment produced striking inhibition of tumor growth and resulted in a 97.2% suppression of lung metastasis. Thus, the phospholipids membrane-coated nanocatalase system represents an encouraging nanoplatform to relieve tumor hypoxia and synergize the chemo-photodynamic cancer therapy.

Serum protein-based nanoparticles for cancer diagnosis and treatment

Serum protein as naturally essential biomacromolecules has recently emerged as a versatile carrier for diagnostic and therapeutic drug delivery for cancer nanomedicine with superior biocompatibility, improved pharmacokinetics and enhanced targeting capacity. A variety of serum proteins have been utilized for drug delivery, mainly including albumin, ferritin/apoferritin, transferrin, low-density lipoprotein, high-density lipoprotein and hemoglobin. As evidenced by the success of paclitaxel-bound albumin nanoparticles (Abraxane^TM), serum protein-based nanoparticles have gained attractive attentions for precise biological design and potential clinical application. In this review, we summarize the general design strategies, targeting mechanisms and recent development of serum protein-based nanoparticles in the field of cancer nanomedicine. Moreover, we also concisely specify the current challenges to be addressed for a bright future of serum protein-based nanomedicines.

Folate-Targeted Cholesterol-Grafted Lipo-Polymeric Nanoparticles for Chemotherapeutic Agent Delivery

Docetaxel (DTX), an FDA approved chemotherapeutic agent, is used as a first-line treatment for triple-negative breast cancer (TNBC). Its poor aqueous solubility, rapid metabolism, short half-life, and effective targeting to the cancer cells limits its optimal therapeutic use. Herein, we report folate targeted amphiphilic lipopolymer grafted with cholesterol conjugated carbonate and DL-lactide prepared by microwave assisted ring opening polymerization, for the efficient actively targeted delivery of DTX. The DTX-loaded folate-targeted lipopolymeric nanoparticles (F-DTX-LPNs) prepared by the emulsion solvent evaporation method exhibited a smaller size of ∼115.17 nm with a PDI of 0.205 and encapsulation efficiency of >80%. Further, these lipopolymeric nanoparticles (F-DTX-LPNs) showed a good on-bench stability and sustained DTX release for 7 days. Cell-based assays in MDA-MB-231 cells revealed a significant enhancement in the intracellular uptake of folate-targeted lipopolymeric nanoparticles compared to non-targeted nanoparticles. Further, methyl beta-cyclodextrin (Mβ-CD) completely inhibited the uptake of these nanoparticles in the cells, indicating a lipid raft-mediated uptake mechanism. The developed F-DTX-LPNs showed improved cytotoxicity, apoptosis, and significant fold-change in expression levels of Bcl-2, BAX and Ki-67 as compared to non-targeted DTX-LPNs and free DTX. Further, F-DTX-LPNs showed an improved in vivo pharmacokinetic profile in Sprague Dawley rats as compared to the free DTX. The bio-imaging of ex vivo tissues demonstrated that the DiR loaded folate targeted LPNs exhibited intense signals after 24 h because of slow release of DiR dye from the nanoparticles.

Expanding sacrificially printed microfluidic channel-embedded paper devices for construction of volumetric tissue models in vitro

We report a method for expanding microchannel-embedded paper devices using a precisely controlled gas-foaming technique for the generation of volumetric tissue models in vitro. We successfully fabricated hollow, perfusable microchannel patterns contained in a densely entangled network of bacterial cellulose nanofibrils using matrix-assisted sacrificial three-dimensional printing, and demonstrated the maintenance of their structural integrity after gas-foaming-enabled expansion in an aqueous solution of NaBH₄. The resulting expanded microchannel-embedded paper devices showed multilayered laminar structures with controllable thicknesses as a function of both NaBH₄ concentration and expansion time. With expansion, the thickness and porosity of the bacterial cellulose network were significantly increased. As such, cellular infiltration was promoted comparing to as-prepared, non-expanded devices. This simple technique enables the generation of truly volumetric, cost-effective human-based tissue models, such as vascularized tumor models, for potential applications in preclinical drug screening and personalized therapeutic selection.

Metastatic status of sentinel lymph nodes in breast cancer determined with photoacoustic microscopy via dual-targeting nanoparticles

Detection of sentinel lymph nodes (SLNs) is critical to guide the treatment of breast cancer. However, distinguishing metastatic SLNs from normal and inflamed lymph nodes (LNs) during surgical resection remains a challenge. Here, we report a CD44 and scavenger receptor class B1 dual-targeting hyaluronic acid nanoparticle (5K-HA-HPPS) loaded with the near-infra-red fluorescent dye DiR-BOA for SLN imaging in breast cancer. The small sized (~40 nm) self-assembled 5K-HA-HPPSs accumulated rapidly in the SLNs after intradermal injection. Compared with normal popliteal LNs (N-LN), there were ~3.2-fold and ~2.4-fold increases in fluorescence intensity in tumour metastatic SLNs (T-MLN) and inflamed LNs (Inf-LN), respectively, 6 h after nanoparticle inoculation. More importantly, photoacoustic microscopy (PAM) of 5K-HA-HPPS showed a significantly distinct distribution in T-MLN compared with N-LN and Inf-LN. Signals were mainly distributed at the centre of T-MLN but at the periphery of N-LN and Inf-LN. The ratio of PA intensity (R) at the centre of the LNs compared with that at the periphery was 5.93 ± 0.75 for T-MLNs of the 5K-HA-HPPS group, which was much higher than that for the Inf-LNs (R = 0.2 ± 0.07) and N-LNs (R = 0.45 ± 0.09). These results suggest that 5K-HA-HPPS injection combined with PAM provides a powerful tool for distinguishing metastatic SLNs from pLNs and inflamed LNs, thus guiding the removal of SLNs during breast cancer surgery.

Vascular and extracellular matrix remodeling by physical approaches to improve drug delivery at the tumor site

INTRODUCTION

Modern comprehensive studies of tumor microenvironment changes allowed scientists to develop new and more efficient strategies that will improve anticancer drug delivery on site. The tumor microenvironment, especially the dense extracellular matrix, has a recognized capability to hamper the penetration of conventional drugs. Development and co-applications of strategies aiming at remodeling the tumor microenvironment are highly demanded to improve drug delivery at the tumor site in a therapeutic prospect.

AREAS COVERED

Increasing indications suggest that classical physical approaches such as exposure to ionizing radiations, hyperthermia or light irradiation, and emerging ones as sonoporation, electric field or cold plasma technology can be applied as standalone or associated strategies to remodel the tumor microenvironment. The impacts on vasculature and extracellular matrix remodeling of these physical approaches will be discussed with the goal to improve nanotherapeutics delivery at the tumor site.

EXPERT OPINION

Physical approaches to modulate vascular properties and remodel the extracellular matrix are of particular interest to locally control and improve drug delivery and thus increase its therapeutic index. They are particularly powerful as adjuvant to nanomedicine delivery; the development of these technologies could have extremely widespread implications for cancer treatment.[Figure: see text].

Tumor-Activated Size-Enlargeable Bioinspired Lipoproteins Access Cancer Cells in Tumor to Elicit Anti-Tumor Immune Responses

The limited lymphocytes infiltration and immunosuppression in tumor are the major challenges of cancer immunotherapy. The use of immunogenic cell death (ICD)-inducing agents has potential to potentiate antitumor immune responses, but is tremendously hampered by the poor delivery efficiency. Herein, a tumor-activated size-enlargeable bioinspired lipoprotein of oxaliplatin (TA-OBL) is designed to access cancer cells and boost the ICD-induced antitumor immunity for synergizing immune-checkpoint blockades (ICBs)-mediated immunotherapy. TA-OBL is constructed by integrating a legumain-sensitive melittin conjugate for improving intratumoral permeation and cancer cell accessibility, a pH-sensitive phospholipid for triggering size-enlargement and drug release in intracellular acidic environments, a nitroreductase-sensitive hydrophobic oxaliplatin prodrug (N-OXP) for eliciting antitumor immunity into the bioinspired nano-sized lipoprotein system. TA-OBL treatment produced robust antitumor immune responses and its combination with ICBs demonstrates strong therapeutic benefits with delayed tumor growth and extended survival rate, making it a promising delivery nanoplatform to elicit antitumor immunity for cancer immunotherapy.

Chemo-Photothermal Combination Cancer Therapy with ROS Scavenging, Extracellular Matrix Depletion, and Tumor Immune Activation by Telmisartan and Diselenide-Paclitaxel Prodrug Loaded Nanoparticles

Extracellular matrix (ECM) accumulating in the tumor microenvironment (TME) is generated by tumor-associated fibroblasts. It can elevate interstitial fluid pressure and form dense barriers in tumor tissues. Consequently, nanocarriers are hindered from permeating into deeper tumor sites. Thus, the programmed drug-releasing nanoparticles, G(TM)PPSP, were developed for TME remodeling and breast cancer therapy. Gelatin nanoparticles were linked with platinum nanoparticles (PtNPs) to obtain G(TM)PPSP with a size of 214.0 ± 5.0 nm. Telmisartan (TM) was loaded in gelatin nanoparticles. Paclitaxel (PTX) was attached to PtNPs via a dual redox responsive diselenide bond. TM release was mediated by MMP-2 because of gelatin degradation in TME, and then intracellular PTX was released because of diselenide linkage fracture triggered by ROS or glutathione. ECM was depleted owing to TGF-β downregulation by TM and direct ablation by the photothermal effect of PtNPs. 4T1 tumor progression was inhibited by PTX chemotherapy, intracellular ROS scavenging of PtNPs, and photothermal therapy (PTT). The tumor spheroid penetration assay proved G(TM)PPSP could permeate into deep tumor regions when MMP-2 existed. In vivo antitumor experiments implied G(TM)PPSP with PTT could inhibit tumor growth effectively and remodel TME via ECM depletion and immunity activation, indicating the potential of G(TM)PPSP-based chemo-photothermal combination therapy for breast cancer treatment.

Membrane-core nanoparticles for cancer nanomedicine

Cancer is one of the most severe disease burdens in modern times, with an estimated increase in the number of patients diagnosed globally from 18.1 million in 2018 to 23.6 million in 2030. Despite a significant progress achieved by conventional therapies, they have limitations and are still far from ideal. Therefore, safe, effective and widely-applicable treatments are urgently needed. Over the past decades, the development of novel delivery approaches based on membrane-core (MC) nanostructures for transporting chemotherapeutics, nucleic acids and immunomodulators has significantly improved anticancer efficacy and reduced side effects. In this review, the formulation strategies based on MC nanostructures for delivery of anticancer drug are described, and recent advances in the application of MC nanoformulations to overcome the delivery hurdles for clinical translation are discussed.

Comprehensive approach of hybrid nanoplatforms in drug delivery and theranostics to combat cancer

To date, various chemically synthesized and biosynthesized nanoparticles, or hybrid nanosystems and/or nanoplatforms, have been developed under the umbrella of nanomedicine. These can be introduced into the body orally, nasally, intratumorally or intravenously. Successfully translating hybrid nanoplatforms from preclinical proof-of-concept to therapeutic value in the clinic is challenging. Having made significant advances with drug delivery technologies, we must learn from other areas of oncology drug development, where patient stratification and target-driven design have improved patient outcomes. This review aims to identify gaps in our understanding of the current strengths of nanomedicine platforms in drug delivery and cancer theranostics. We report on the current approaches of nanomedicine at preclinical and clinical stages.

Reprogramming Tumor Microenvironment with Photothermal Therapy

The tumor microenvironment significantly influences cancer progression and therapeutic response. Reprogramming of tumor microenvironment has emerged as a strategy to assist conventional cancer treatment. In recent years, photothermal therapy has received considerable attention owing to its noninvasiveness, high temporal-spatial resolution, and minimal drug resistance. Apart from ablating cancer cells by generating heat upon light irradiation, photothermal therapy can also affect the tumor microenvironment, such as disrupting the tumor extracellular matrix and tumor vasculature. Moreover, cancer cell death by hyperthermia could potentially activate the immune system to fight against tumor. In this topical review, we focus on the recent progress of photothermal therapy based on tumor microenvironment remodeling, aiming to better guide the design of nanoparticles for cancer photoimmunotherapy.

Evaluation of the tumor-targeting efficiency and intratumor heterogeneity of anticancer drugs using quantitative mass spectrometry imaging

The development of improved or targeted drugs that discriminate between normal and tumor tissues is the key therapeutic issue in cancer research. However, the development of an analytical method with a high accuracy and sensitivity to achieve quantitative assessment of the tumor targeting of anticancer drugs and even intratumor heterogeneous distribution of these drugs at the early stages of drug research and development is a major challenge. Mass spectrometry imaging is a label-free molecular imaging technique that provides spatial-temporal information on the distribution of drugs and metabolites in organisms, and its application in the field of pharmaceutical development is rapidly increasing. Methods: The study presented here accurately quantified the distribution of paclitaxel (PTX) and its prodrug (PTX-R) in whole-body animal sections based on the virtual calibration quantitative mass spectrometry imaging (VC-QMSI) method, which is label-free and does not require internal standards, and then applied this technique to evaluate the tumor targeting efficiency in three treatment groups-the PTX-injection treatment group, PTX-liposome treatment group and PTX-R treatment group-in nude mice bearing subcutaneous A549 xenograft tumors. Results: These results indicated that PTX was widely distributed in multiple organs throughout the dosed body in the PTX-injection group and the PTX-liposome group. Notably, in the PTX-R group, both the prodrug and metabolized PTX were mainly distributed in the tumor tissue, and this group showed a significant difference compared with the PTX-liposome group, the relative targeting efficiency of PTX-R group was increased approximately 50-fold, leading to substantially decreased systemic toxicities. In addition, PTX-R showed a significant and specific accumulation in the poorly differentiated intratumor area and necrotic area. Conclusion: This method was demonstrated to be a reliable, feasible and easy-to-implement strategy to quantitatively map the absorption, distribution, metabolism and excretion (ADME) of a drug in the whole-body and tissue microregions and could therefore evaluate the tumor-targeting efficiency of anticancer drugs to predict drug efficacy and safety and provide key insights into drug disposition and mechanisms of action and resistance. Thus, this strategy could significantly facilitate the design and optimization of drugs at the early stage of drug research and development.

Nanoparticles-mediated reoxygenation strategy relieves tumor hypoxia for enhanced cancer therapy

Tumor hypoxia is a characteristic hallmark of malignant solid tumors, which remains an essential impediment to many current treatments like chemotherapy, radiotherapy, photodynamic therapy and immunotherapy, thereby leading to poor clinical prognosis after therapy. Rationally, modulating tumor hypoxia can be of great interest to augment the therapeutic efficacy of these treatments. In this review, we focus our discussion on current advances in nanoparticles-mediated tumor reoxygenation strategy for relieving tumor hypoxia to improve the therapeutic efficacy of versatile therapies. These nanoparticles can improve tumor oxygen levels via nanoparticles-mediated oxygen-carrying or oxygen-generating tactics to synergize the effectiveness of many current therapeutic modalities. Based on these considerable summaries and analyses, we propose some feasible perspectives on nanoparticles-based tumor reoxygenations to ameliorate the therapeutic outcomes.

Electrochemiluminescence-Microscopy for microRNA Imaging in Single Cancer Cell Combined with Chemotherapy-Photothermal Therapy

In this work, a new technology using ECL as a microscopy to parallel image miRNA-21 in single cancer cell was built. Phorbol-12-myristate-13-acetate (PMA) loaded gold nanocages (Au NCs) was closed with DNA gate which could be recognized and opened by miRNA-21 in HeLa cell. PMA was then released and further induced HeLa cells to produce reactive oxygen species (ROS; including O^2-•, •OH and H₂O₂ etc.). With H₂O₂ as coreactant and luminol as ECL active material, ECL imaging of intracellular miRNA-21 in single HeLa cell was obtained by EMCCD. Moreover, ROS therapy and photothermal therapy (PPT) of Au NCs@PMA probe were also motivated by in situ miRNA-21 marker instead of the external source. The combined therapy leads to dramatically enhanced ability for cancer cell killing. Au NCs@PMA probe alone could not only achieve a high sensitivity and high resolution ECL-microscopy for imaging of intracellular miRNA-21 for the first time, but also realize the integrated diagnosis like ROS induced tumor damage and photothermal-induced intelligent therapy. This multifunctional platform is believed to be capable of playing an important role in future oncotherapy by the synergistic effects between chemotherapy and photothermal therapy.