Nano-delivery systems focused on tumor microenvironment regulation and biomimetic strategies for treatment of breast cancer metastasis

A precision intelligent nanomissile for inhibiting tumor metastasis, boosting energy deprivation and immunotherapy

The epithelial-mesenchymal transition (EMT), tumor stroma and local metabolic alterations cooperate to establish a unique tumor microenvironment (TME) that fosters tumor progression and metastasis. To tackle this challenge, a precision intelligent nanomissile named HA@AT-Pd has been designed for dual-pronged cancer-associated fibroblast (CAF) transformation and tumor cell elimination. It is observed that HA@AT-Pd inhibits the production of cancer stem cells (CSCs) by blocking the TGF-β/Smad signaling pathway-mediated EMT and reversing activated CAFs to quiescence. Notably, HA@AT-Pd induces energy depletion in breast cancer cells through simultaneously suppressing cellular oxidative phosphorylation and glycolysis. The inhibition of glycolysis results in reduced lactic acid production, thereby converting an immunosuppressive TME into an immune-activating environment. Furthermore, the photothermal effect generated by HA@AT-Pd evokes immunogenic cell death, which can further enhance the anti-tumor immune response. Overall, this multifunctional combination strategy unveils potential therapeutic avenues to inhibit tumor progression and metastasis.

A quercetin nanoparticle combined with a 3D-printed decellularized extracellular matrix/ gelatin methacryloyl/sodium alginate biomimetic tumor model for the treatment of melanoma

The traditional drug efficacy testing often conducted using two-dimensional (2D) cell culture methods, which do not accurately replicate the complexity of the tumor microenvironment. Melanoma in particular, is known for its high incidence, and aggressive nature, highlighting the need for more sophisticated in vitro models that better simulate the tumor's true biological microenvironment drug research and therapy. In this study, we developed quercetin nanoparticles (QueNPs) with enhanced water solubility and promising tumor therapeutic effects. These nanoparticles were formed through the self-assembly of Pluronic F127 (PF127) and quercetin (Que). To better mimic the in vivo tumor environment, we also created a composite scaffold using three-dimensional (3D) printing technology, incorporating a decellularized extracellular matrix (dECM), which closely resembles the native tissue microenvironment. The scaffold also included gelatin methacryloyl (GelMA), which forms a polymeric network via photocrosslinking, and sodium alginate (SA), which enhances structural stability through ion cross-linking with calcium ions. This combination was used to construct a more physiologically relevant 3D melanoma model. The anti-cancer effects of QueNPs were assessed in both 2D and 3D culture systems. The results showed that tumor cells in the 3D model formed cluster and distributed across the scaffold, creating a more realistic tumor microenvironment compared to the 2D system. Cells in the 3D tumor model exhibited significant resistance to QueNPs, with a time dependent response that resulted in a killing rate of over 90 % by day 14. These findings highlight the efficiency of the QueNPs in the 3D melanoma model and emphasize the importance of incorporation 3D printing and nanomedicine for more accurate and effective drug screening.

Bioresponsive Nanoparticles Boost Starvation Therapy and Prevent Premetastatic Niche Formation for Pulmonary Metastasis Treatment

In the process of tumor metastasis, tumor cells can acquire invasion by excessive uptake of nutrients and energy and interact with the host microenvironment to shape a premetastatic niche (PMN) that facilitates their colonization and progression in the distal sites. Pyruvate is an essential nutrient that engages in both energy metabolism and remodeling of the extracellular matrix (ECM) in the lungs for PMN formation, thus providing a target for tumor metastasis treatment. There is a paucity of strategies focusing on PMN prevention, which is key to metastasis inhibition. Here, we design a bioresponsive nanoparticle (HP/GU) based on a disulfide-cross-linked hyperbranched polyethylenimine (D-PEI) core and a hyaluronic acid (HA) shell with a reactive oxygen species (ROS)-sensitive cross-linker between them to encapsulate glucose oxidase (GOX) and a mitochondrial pyruvate carrier (MPC) inhibitor via electrostatic interaction, which reinforces starvation therapy and reduces PMN formation in the lungs via inhibiting pyruvate metabolism. In tumor cells, GOX and MPC inhibitors can be rapidly released and synergistically reduce the energy supply of tumor cells by consuming glucose and inhibiting pyruvate uptake to decrease tumor cell invasion. MPC inhibitors can also reduce ECM remodeling by blocking cellular pyruvate metabolism to prevent PMN formation. Consequently, HP/GU achieves an efficient inhibition of both primary and metastatic tumors and provides an innovative strategy for the treatment of tumor metastases.

Nano-drug delivery system for the treatment of multidrug-resistant breast cancer: Current status and future perspectives

Breast cancer (BC) is one of the most frequently diagnosed cancers in women. Chemotherapy continues to be the treatment of choice for clinically combating it. Nevertheless, the chemotherapy process is frequently hindered by multidrug resistance, thereby impacting the effectiveness of the treatment. Multidrug resistance (MDR) refers to the phenomenon in which malignant tumour cells develop resistance to anticancer drugs after one single exposure. It can occur with a broad range of chemotherapeutic drugs with distinct chemical structures and mechanisms of action, and it is one of the major causes of treatment failure and disease relapse. Research has long been focused on overcoming MDR by using multiple drug combinations, but this approach is often associated with serious side effects. Therefore, there is a pressing need for in-depth research into the mechanisms of MDR, as well as the development of new drugs to reverse MDR and improve the efficacy of breast cancer chemotherapy. This article reviews the mechanisms of multidrug resistance and explores the application of nano-drug delivery system (NDDS) to overcome MDR in breast cancer. The aim is to offer a valuable reference for further research endeavours.

Targeting tumor-associated macrophages with nanocarrier-based treatment for breast cancer: A step toward developing innovative anti-cancer therapeutics

Tumor-associated macrophages (TAMs) promote tumor advancement in many ways, such as inducing angiogenesis and the formation of new blood vessels that provide tumors with nourishment and oxygen. TAMs also facilitate tumor invasion and metastasis by secreting enzymes that degrade the extracellular matrix and generating pro-inflammatory cytokines that enhance the migration of tumor cells. TAMs also have a role in inhibiting the immune response against malignancies. To accomplish this, they release immunosuppressive cytokines such as IL-10, and TAMs can hinder the function of T cells and natural killer cells, which play crucial roles in the immune system's ability to combat cancer. The role of TAMs in breast cancer advancement is a complex and dynamic field of research. Therefore, TAMs are a highly favorable focus for innovative breast cancer treatments. This review presents an extensive overview of the correlation between TAMs and breast cancer development as well as its role in the tumor microenvironment (TME) shedding light on their impact on tumor advancement and immune evasion mechanisms. Notably, our study provides an innovative approach to employing nanomedicine approaches for targeted TAM therapy in breast cancer, providing an in-depth overview of recent advances in this emerging field.

Tumor Microenvironment Responsive RNA Drug Delivery Systems: Intelligent Platforms for Sophisticated Release

Cancer is a significant health concern, increasingly showing insensitivity to traditional treatments, highlighting the urgent need for safer and more practical treatment options. Ribonucleic acid (RNA) gene therapy drugs have demonstrated promising potential in preclinical and clinical trials for antitumor therapy by regulating tumor-related gene expression. However, RNA's poor membrane permeability and stability restrict its effectiveness in entering and being utilized in cells. An appropriate delivery system is crucial for achieving targeted tumor effects. The tumor microenvironment (TME), characterized by acidity, hypoxia, enzyme overexpression, elevated glutathione (GSH) concentration, and excessive reactive oxygen species (ROS), is essential for tumor survival. Furthermore, these distinctive features can also be harnessed to develop intelligent drug delivery systems. Various nanocarriers that respond to the TME have been designed for RNA drug delivery, showing the advantages of tumor targeting and low toxicity. This Review discusses the abnormal changes of components in TME, therapeutic RNAs' roles, underlying mechanisms, and the latest developments in utilizing vectors that respond to microenvironments for treating tumors. We hope it provides insight into creating and optimizing RNA delivery vectors to improve their effectiveness.

Macrophage membrane-based biomimetic nanocarrier system for enhanced immune activation and combination therapy in liver cancer

Previous studies have demonstrated that the combination of photodynamic therapy, photothermal therapy and chemotherapy is highly effective in treating hepatocellular carcinoma (HCC). However, the clinical application of this approach has been hindered by the lack of efficient and low-toxicity drug delivery platforms. To address this issue, we developed a novel biomimetic nanocarrier platform named ZID@RM, which utilizes ZIF8 functional nanoparticles encapsulated with macrophage membrane and loaded with indocyanine green and doxorubicin. The bionic nanocarrier platform has good biocompatibility, reducing the risk of rapid clearance by macrophages and improving the targeting ability for HCC cells. Under the dual regulation of acidity and infrared light, ZID@RM stimulated the generation of abundant reactive oxygen species within HCC cells, induced tumor cell pyroptosis and promoted the release of damage-associated molecular patterns to induce immune responses. In the future, this technology platform has the potential to provide personalized and improved healthcare by using patients' own macrophage membranes to create an efficient drug delivery system for tumor therapy.Graphical abstract Scheme 1 Schematic representation of the synthesis of a biomimetic nanomedicine delivery platform (ZID@RM) and its application in tumor imaging-guided combination therapy.

Platinum-based chemotherapy: trends in organic nanodelivery systems

Despite the investment in platinum drugs research, cisplatin, carboplatin and oxaliplatin are still the only Pt-based compounds used as first line treatments for several cancers, with a few other compounds being approved for administration in some Asian countries. However, due to the severe and worldwide impact of oncological diseases, there is an urge for improved chemotherapeutic approaches. Furthermore, the pharmaceutical application of platinum complexes is hindered by their inherent toxicity and acquired resistance. Nanodelivery systems rose as a key strategy to overcome these challenges, with recognized versatility and ability towards improving the safety, bioavailability and efficacy of the available drugs. Among the known nanocarriers, organic systems have been widely applied, taking advantage of their potential as drug vehicles. Researchers have mainly focused on the development of lipidic and polymeric carriers, including supramolecular structures, with an overall improvement of encapsulated platinum complexes. Herein, an overview of recent trends and strategies is presented, with the main focus on the encapsulation of platinum compounds into organic nanocarriers, showcasing the evolution in the design and development of these promising systems. This comprehensive review highlights formulation methods as well as characterization procedures, providing insights that may be helpful for the development of novel platinum nanocarriers aiming at future pharmaceutical applications.

ROS-responsive core-shell nano-inhibitor impedes pyruvate metabolism for reinforced photodynamic therapy and interrupted pre-metastatic niche formation

The formation of pre-metastatic niche (PMN) in a hospitable organ derived from the primary tumor requires the communication between the tumor cells and the host environment. Pyruvate is a fundamental nutrient by which the tumor cells metabolically reshape the extracellular matrix in the lung to facilitate their own metastatic development. Here we report a combination regimen by integrating the photo-sensitizer and the mitochondrial pyruvate carrier (MPC) inhibitor in a dendritic polycarbonate core-hyaluronic acid shell nano-platform with multivalent reversible crosslinker embedded in it (DOH-NI+L) to reinforce photodynamic therapy (PDT) toward the primary tumor and interrupt PMN formation in the lung via impeding pyruvate uptake. We show that DOH-NI+L mediates tumor-specific MPC inhibitor liberation, inhibiting the aerobic respiration for facilitated PDT and restraining ATP generation for paralyzing cell invasion. Remarkably, DOH-NI+L is demonstrated to block the metabolic crosstalk of tumor cell-host environment by dampening pyruvate metabolism, provoking a series of metabolic responses and resulting in the pulmonary PMN interruption. Consequently, DOH-NI+L realizes a significant primary tumor inhibition and an efficient pulmonary metastasis prevention. Our research extends nano-based anti-metastatic strategies aiming at PMN intervention and such a dendritic core-shell nano-inhibitor provides an innovative paradigm to inhibit tumor growth and prevent metastasis efficiently. STATEMENT OF SIGNIFICANCE: In the progression of cancer metastasis, the formation of a pre-metastatic niche (PMN) in a hospitable organ derived from the primary tumor is one of the rate-limiting stages. The current nano-based anti-metastatic modalities mainly focus on targeted killing of tumor cells and specific inhibition of tumor cell invasion, while nanomedicine-mediated interruption of PMN formation has been rarely reported. Here we report a combination regimen by integrating a photo-sensitizer and an inhibitor of mitochondrial pyruvate carrier in a dendritic core-shell nano-platform with a reversible crosslinker embedded in it to reinforce PDT toward the primary tumor and interrupt PMN formation via impeding the uptake of pyruvate that is a fundamental nutrient facilitating aerobic respiration and PMN formation. Our research proposed a nano-based anti-metastatic strategy aiming at PMN intervention.

Shifting cold to hot tumors by nanoparticle-loaded drugs and products

Cold tumors lack antitumor immunity and are resistant to therapy, representing a major challenge in cancer medicine. Because of the immunosuppressive spirit of the tumor microenvironment (TME), this form of tumor has a low response to immunotherapy, radiotherapy, and also chemotherapy. Cold tumors have low infiltration of immune cells and a high expression of co-inhibitory molecules, such as immune checkpoints and immunosuppressive molecules. Therefore, targeting TME and remodeling immunity in cold tumors can improve the chance of tumor repression after therapy. However, tumor stroma prevents the infiltration of inflammatory cells and hinders the penetration of diverse molecules and drugs. Nanoparticles are an intriguing tool for the delivery of immune modulatory agents and shifting cold to hot tumors. In this review article, we discuss the mechanisms underlying the ability of nanoparticles loaded with different drugs and products to modulate TME and enhance immune cell infiltration. We also focus on newest progresses in the design and development of nanoparticle-based strategies for changing cold to hot tumors. These include the use of nanoparticles for targeted delivery of immunomodulatory agents, such as cytokines, small molecules, and checkpoint inhibitors, and for co-delivery of chemotherapy drugs and immunomodulatory agents. Furthermore, we discuss the potential of nanoparticles for enhancing the efficacy of cancer vaccines and cell therapy for overcoming resistance to treatment.

Natural biomimetic nano-system for drug delivery in the treatment of rheumatoid arthritis: a literature review of the last 5 years

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized primarily by synovitis, leading to the destruction of articular cartilage and bone and ultimately resulting in joint deformity, loss of function, and a significant impact on patients' quality of life. Currently, a combination of anti-rheumatic drugs, hormonal drugs, and biologics is used to mitigate disease progression. However, conventional drug therapy has limited bioavailability, and long-term use often leads to drug resistance and toxic side effects. Therefore, exploring new therapeutic approaches for RA is of great clinical importance. Nanodrug delivery systems offer promising solutions to overcome the limitations of conventional drugs. Among them, liposomes, the first nanodrug delivery system to be approved for clinical application and still widely studied, demonstrate the ability to enhance therapeutic efficacy with fewer adverse effects through passive or active targeting mechanisms. In this review, we provide a review of the research progress on the targeting mechanisms of various natural biomimetic nano-delivery systems in RA therapy. Additionally, we predict the development trends and application prospects of these systems, offering new directions for precision treatment of RA.

Biomimetic Nano-Drug Delivery System: An Emerging Platform for Promoting Tumor Treatment

With the development of nanotechnology, nanoparticles (NPs) have shown broad prospects as drug delivery vehicles. However, they exhibit certain limitations, including low biocompatibility, poor physiological stability, rapid clearance from the body, and nonspecific targeting, which have hampered their clinical application. Therefore, the development of novel drug delivery systems with improved biocompatibility and high target specificity remains a major challenge. In recent years, biofilm mediated biomimetic nano-drug delivery system (BNDDS) has become a research hotspot focus in the field of life sciences. This new biomimetic platform uses bio-nanotechnology to encapsulate synthetic NPswithin biomimetic membrane, organically integrating the low immunogenicity, low toxicity, high tumor targeting, good biocompatibility of the biofilm with the adjustability and versatility of the nanocarrier, and shows promising applications in the field of precision tumor therapy. In this review, we systematically summarize the new progress in BNDDS used for optimizing drug delivery, providing a theoretical reference for optimizing drug delivery and designing safe and efficient treatment strategies to improve tumor treatment outcomes.

Cell Membrane Biomimetic Nano-Delivery Systems for Cancer Therapy

Nano-delivery systems have demonstrated great promise in the therapy of cancer. However, the therapeutic efficacy of conventional nanomedicines is hindered by the clearance of the blood circulation system and the physiological barriers surrounding the tumor. Inspired by the unique capabilities of cells within the body, such as immune evasion, prolonged circulation, and tumor-targeting, there has been a growing interest in developing cell membrane biomimetic nanomedicine delivery systems. Cell membrane modification on nanoparticle surfaces can prolong circulation time, activate tumor-targeting, and ultimately improve the efficacy of cancer treatment. It shows excellent development potential. This review will focus on the advancements in various cell membrane nano-drug delivery systems for cancer therapy and the obstacles encountered during clinical implementation. It is hoped that such discussions will inspire the development of cell membrane biomimetic nanomedical systems.

Current advances in nanoformulations of therapeutic agents targeting tumor microenvironment to overcome drug resistance

The tumor microenvironment (TME) plays a pivotal role in cancer development and progression. In this line, revealing the precise mechanisms of the TME and associated signaling pathways of tumor resistance could pave the road for cancer prevention and efficient treatment. The use of nanomedicine could be a step forward in overcoming the barriers in tumor-targeted therapy. Novel delivery systems benefit from enhanced permeability and retention effect, decreasing tumor resistance, reducing tumor hypoxia, and targeting tumor-associated factors, including immune cells, endothelial cells, and fibroblasts. Emerging evidence also indicates the engagement of multiple dysregulated mediators in the TME, such as matrix metalloproteinase, vascular endothelial growth factor, cytokines/chemokines, Wnt/β-catenin, Notch, Hedgehog, and related inflammatory and apoptotic pathways. Hence, investigating novel multitargeted agents using a novel delivery system could be a promising strategy for regulating TME and drug resistance. In recent years, small molecules from natural sources have shown favorable anticancer responses by targeting TME components. Nanoformulations of natural compounds are promising therapeutic agents in simultaneously targeting multiple dysregulated factors and mediators of TME, reducing tumor resistance mechanisms, overcoming interstitial fluid pressure and pericyte coverage, and involvement of basement membrane. The novel nanoformulations employ a vascular normalization strategy, stromal/matrix normalization, and stress alleviation mechanisms to exert higher efficacy and lower side effects. Accordingly, the nanoformulations of anticancer monoclonal antibodies and conventional chemotherapeutic agents also improved their efficacy and lessened the pharmacokinetic limitations. Additionally, the coadministration of nanoformulations of natural compounds along with conventional chemotherapeutic agents, monoclonal antibodies, and nanomedicine-based radiotherapy exhibits encouraging results. This critical review evaluates the current body of knowledge in targeting TME components by nanoformulation-based delivery systems of natural small molecules, monoclonal antibodies, conventional chemotherapeutic agents, and combination therapies in both preclinical and clinical settings. Current challenges, pitfalls, limitations, and future perspectives are also discussed.

Cross-scale tracing of nanoparticles and tumors at the single-cell level using the whole-lung atlas

Currently, the effectiveness of oncotherapy is limited by tumor heterogeneities, which presents a huge challenge for the development of nanotargeted drug delivery systems (DDSs). Therefore, it is important to resolve the spatiotemporal interactions between tumors and nanoparticles. However, targeting evaluation has been limited by particle visualization due to the gap between whole-organ scale and subcellular precision. Here, a high-precision three-dimensional (3D) visualization of tumor structure based on the micro-optical sectioning tomography (MOST) system and fluorescence MOST (fMOST) system is presented to clarify 3D spatial distribution of nanoparticles within the tumor. We demonstrate that through the MOST/fMOST system, it is possible to reveal multidimensional and cross-scale correlations between the tumor structure and nanoparticle distribution to remodel the tumor microenvironment and explore the structural parameters of vasculature. This visualization methodology provides an accurate assessment of the efficacy, distribution, and targeting efficiency of DDSs for oncotherapy compared to available approaches.

Enzyme/pH dual stimuli-responsive nanoplatform co-deliver disulfiram and doxorubicin for effective treatment of breast cancer lung metastasis

OBJECTIVES

Metastasis is still one of the main obstacles in the treatment of breast cancer. This study aimed to develop disulfiram (DSF) and doxorubicin (DOX) co-loaded nanoparticles (DSF-DOX NPs) with enzyme/pH dual stimuli-responsive characteristics to inhibit breast cancer metastasis.

METHODS

DSF-DOX NPs were prepared using the amphiphilic poly(ε-caprolactone)-b-poly(L-glutamic acid)-g-methoxy poly(ethylene glycol) (PCL-b-PGlu-g-mPEG) copolymer by a classical dialysis method. In vitro release tests, in vitro cytotoxicity assay, and anti-metastasis studies were conducted to evaluate pH/enzyme sensitivity and therapeutic effect of DSF-DOX NPs.

RESULTS

The specific pH and enzyme stimuli-responsiveness of DSF-DO NPs can be attributed to the transformation of secondary structure and the degradation of amide bonds in the PGlu segment, respectively. This accelerated drug release significantly increased the cytotoxicity to 4T1 cells. Compared with the control group, the DSF-DOX NPs showed a strong inhibition of in vitro metastasis with a wound healing rate of 36.50% and a migration rate of 18.39%. Impressively, in vivo anti-metastasis results indicated that the metastasis of 4T1 cells was almost completely suppressed by DSF-DOX NPs.

CONCLUSION

DSF-DOX NPs with controllable tumor site delivery of DOX and DSF were a prospectively potential strategy for metastatic breast cancer treatment.

Reduction-Hypersensitive Podophyllotoxin Prodrug Self-Assembled Nanoparticles for Cancer Treatment

Podophyllotoxin (PPT) has shown strong antitumor effects on various types of cancers. However, the non-specific toxicity and poor solubility severely limits its clinical transformation. In order to overcome the adverse properties of PPT and explore its clinical potential, three novel PTT-fluorene methanol prodrugs linked by different lengths of disulfide bonds were designed and synthesized. Interestingly, the lengths of the disulfide bond affected the drug release, cytotoxicity, pharmacokinetic characteristics, in vivo biodistribution and antitumor efficacy of prodrug NPs. To be more specific, all three PPT prodrugs could self-assemble into uniform nanoparticles (NPs) with high drug loading (>40%) via the one-step nano precipitation method, which not only avoids the use of surfactants and cosurfactants, but also reduces the systemic toxicity of PPT and increases the tolerated dose. Among the three prodrug NPs, FAP NPs containing α-disulfide bond showed the most sensitive tumor-specific response and fastest drug release rate, thus demonstrating the strongest in vitro cytotoxicity. In addition, three prodrug NPs showed prolonged blood circulation and higher tumor accumulation. Finally, FAP NPs demonstrated the strongest in vivo antitumor activity. Our work will advance the pace of podophyllotoxin towards clinical cancer treatment.

Bioinspired low-density lipoprotein co-delivery system for targeting and synergistic cancer therapy

Epithelial-mesenchymal transition (EMT) is the culprit of tumor invasion and metastasis. As a critical transcription factor that induces EMT, snail is of great importance in tumor progression, and knocking down its expression by small interfering RNA (siRNA) may inhibit tumor metastasis. Herein, we developed a core-shelled bioinspired low-density lipoprotein (bio-LDL) in which snail siRNA-loaded calcium phosphate nanoparticles were wrapped as the core and doxorubicin was embedded in the outer phospholipids modified with a synthetic peptide of apoB100 targeting LDL receptor-abundant tumor cells. Bio-LDL exhibited pH-responsive release, lysosomal escape ability, enhanced cytotoxicity and apoptotic induction. Bio-LDL could significantly inhibit the expression of snail and regulate EMT-related proteins to reduce tumor migration and invasion in vitro. Bio-LDL also displayed favorable tumor targeting and synergistic inhibition of tumor growth and metastasis in vivo. Therefore, the multifunctional bio-LDL will be a promising co-delivery vector and holds potential value for clinical translation.

Innovative nanotheranostics: Smart nanoparticles based approach to overcome breast cancer stem cells mediated chemo- and radioresistances

The alarming increase in the number of breast cancer patients worldwide and the increasing death rate indicate that the traditional and current medicines are insufficient to fight against it. The onset of chemo- and radioresistances and cancer stem cell-based recurrence make this problem harder, and this hour needs a novel treatment approach. Competent nanoparticle-based accurate drug delivery and cancer nanotheranostics like photothermal therapy, photodynamic therapy, chemodynamic therapy, and sonodynamic therapy can be the key to solving this problem due to their unique characteristics. These innovative formulations can be a better cargo with fewer side effects than the standard chemotherapy and can eliminate the stability problems associated with cancer immunotherapy. The nanotheranostic systems can kill the tumor cells and the resistant breast cancer stem cells by novel mechanisms like local hyperthermia and reactive oxygen species and prevent tumor recurrence. These theranostic systems can also combine with chemotherapy or immunotherapy approaches. These combining approaches can be the future of anticancer therapy, especially to overcome the breast cancer stem cells mediated chemo- and radioresistances. This review paper discusses several novel theranostic systems and smart nanoparticles, their mechanism of action, and their modifications with time. It explains their relevance and market scope in the current era. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Improving cellular uptake and bioavailability of periplocymarin-linoleic acid prodrug by combining PEGylated liposome

Periplocymarin (PPM), a cardiac glycoside isolated from Cortex periplocae, has a strong anti-tumor effect against various cancer cells. However, cardiotoxicity and rapid metabolism hinder its clinical applications. In this study, small molecule prodrug was integrated into PEGylated liposome to improve the efficiency of periplocymarin in vivo. The periplocymarin-linoleic acid (PL) prodrug was constructed by conjugating the linoleic acid with PPM via esterification, which was further facilitated to form PEGylated liposome (PL-Lip) through film dispersion. Compared with PL self-assembling nano-prodrug (PL-SNP), PL-Lip showed better colloid stability, sustained drug release kinetics, and enhanced cellular uptake by tumor cells. Notably, PL-Lip performed better than PPM and PL-SNP in terms of tumor distribution and pharmacokinetics, which include bioavailability and half-life. Altogether, the prodrug PEGylated liposome represents a good strategy and method for long-circulating and tumor-targeting delivery of periplocymarin with enhanced clinical application prospect.

Tumor extracellular matrix modulating strategies for enhanced antitumor therapy of nanomedicines

Nanomedicines have shown a promising strategy for cancer therapy because of their higher safety and efficiency relative to small-molecule drugs, while the dense extracellular matrix (ECM) in tumors often acts as a physical barrier to hamper the accumulation and diffusion of nanoparticles, thus compromising the anticancer efficacy. To address this issue, two major strategies including degrading ECM components and inhibiting ECM formation have been adopted to enhance the therapeutic efficacies of nanomedicines. In this review, we summarize the recent progresses of tumor ECM modulating strategies for enhanced antitumor therapy of nanomedicines. Through degrading ECM components or inhibiting ECM formation, the accumulation and diffusion of nanoparticles in tumors can be facilitated, leading to enhanced efficacies of chemotherapy and phototherapy. Moreover, the ECM degradation can improve the infiltration of immune cells into tumor tissues, thus achieving strong immune response to reject tumors. The adoptions of these two ECM modulating strategies to improve the efficacies of chemotherapy, phototherapy, and immunotherapy are discussed in detail. A conclusion, current challenges and outlook are then given.

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Extracellular matrix modulating strategies have been adopted to enhance the therapeutic efficacies of nanomedicines.

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Degrading extracellular matrix components or inhibiting extracellular matrix formation can improve the accumulation and diffusion of nanoparticles in tumors and the infiltration of immune cells into tumor tissues.

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The adoptions of two extracellular matrix modulating strategies to improve the efficacies of chemotherapy, phototherapy, and immunotherapy are summarized.

Nanoparticles for Chemoimmunotherapy Against Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) exhibits high recurrence and mortality rates because of the lack of effective treatment targets. Surgery and traditional chemotherapy are the primary treatment options. Immunotherapy shows high potential for treating various cancers but exhibits limited efficacy against TNBC as a monotherapy. Chemoimmunotherapy has broad prospects for applications for cancer treatment conferred through the synergistic immunomodulatory and anti-tumor effects of chemotherapy and immunotherapeutic strategies. However, improving the efficacy of synergistic therapy and reducing the side effects of multiple drugs remain to be the main challenges in chemoimmunotherapy against TNBC. Nanocarriers can target both cancer and immune cells, promote drug accumulation, and show minimal toxicity, making them ideal delivery systems for chemotherapeutic and immunotherapeutic agents. In this review, we introduce the immunomodulatory effects of chemotherapy and combined mechanisms of chemoimmunotherapy, followed by a summary of nanoparticle-mediated chemoimmunotherapeutic strategies used for treating TNBC. This up-to-date synthesis of relevant findings in the field merits contemplation, while considering avenues of investigation to enable advances in the field.

Nano-delivery systems for food bioactive compounds in cancer: prevention, therapy, and clinical applications

Bioactive compounds represent a broad class of dietary metabolites derived from fruits and vegetables, such as polyphenols, carotenoids and glucosinolates with potential for cancer prevention. Curcumin, resveratrol, quercetin, and β-carotene have been the most widely applied bioactive compounds in chemoprevention. Lately, many approaches to encapsulating bioactive components in nano-delivery systems have improved biomolecules' stability and targeted delivery. In this review, we critically analyze nano-delivery systems for bioactive compounds, including polymeric nanoparticles (NPs), solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), liposomes, niosomes, and nanoemulsions (NEs) for potential use in cancer therapy. Efficacy studies of the nanoformulations using cancer cell lines and in vivo models and updated human clinical trials are also discussed. Nano-delivery systems were found to improve the therapeutic efficacy of bioactive molecules against various types of cancer (e.g., breast, prostate, colorectal and lung cancer) mainly due to the antiproliferation and pro-apoptotic effects of tumor cells. Furthermore, some bioactive compounds have promised combination therapy with standard chemotherapeutic agents, with increased tumor efficiency and fewer side effects. These opportunities were identified and developed to ensure more excellent safety and efficacy of novel herbal medicines enabling novel insights for designing nano-delivery systems for bioactive compounds applied in clinical cancer therapy.

Smart Nanoparticles for Breast Cancer Treatment Based on the Tumor Microenvironment

Breast cancer (BC) is the most common malignant tumor in women. There are different risk characteristics and treatment strategies for different subtypes of BC. The tumor microenvironment (TME) is of great significance for understanding the occurrence, development, and metastasis of tumors. The TME plays an important role in all stages of BC metastasis, immune monitoring, immune response avoidance, and drug resistance, and also plays an important role in the diagnosis, prevention, and prognosis of BC. Smart nanosystems have broad development prospect in the regulation of the BC drug delivery based on the response of the TME. In particular, TME-responsive nanoparticles cleverly utilize the abnormal features of BC tissues and cells to achieve targeted transport, stable release, and improved efficacy. We here present a review of the mechanisms underlying the response of the TME to BC to provide potential nanostrategies for future BC treatment.

Metabolic Reprogramming by Dual-targeting Biomimetic Nanoparticles for Enhanced Tumor Chemo-Immunotherapy

Cancer-associated fibroblasts (CAFs)-mediated metabolic support plays a vital role in tumorigenesis. The metabolic network between cancer cells and CAFs may serve as promising targets for cancer therapy. Here, aiming at targeted blockade of the metabolic support of CAFs to cancer cells, a biomimetic nanocarrier is designed by coating solid lipid nanoparticles containing chemotherapeutic paclitaxel (PTX) and glycolysis inhibitor PFK15 with hybrid membranes of cancer cells and activated fibroblasts. The nanoparticles possess outstanding dual-targeting ability which can simultaneously target cancer cells and CAFs. The encapsulated glycolysis inhibitor PFK15 can prevent the glycolysis of cancer cells and CAFs at the same time, thus increasing the chemosensitivity of cancer cells and blocking the metabolic support of CAFs to cancer cells. The results showed that the combination of PTX and PFK15 exhibited synergistic effects and inhibited tumor growth effectively. Moreover, the biomimetic nanoparticles obviously reduced the lactate production in the tumor microenvironment, leading to activated immune responses and enhanced tumor suppression. This work presents a facile strategy to destroy the metabolic network between cancer cells and CAFs, and proves the potential to elevate chemo-immunotherapy by glycolysis inhibition. STATEMENT OF SIGNIFICANCE: : In many solid tumors, most cancer cells produce energy and carry out biosynthesis through glycolysis, even in aerobic conditions. As the main tumor stromal cells, cancer-associated fibroblasts (CAFs) usually turn oxidative phosphorylation into aerobic glycolysis with metabolic reprogramming and provide high-energy glycolytic metabolites for cancer cells. The metabolic network between cancer cells and CAFs is regarded as the vulnerability among cancer cells. Moreover, lactate produced by cancer cells and CAFs through glycolysis often leads to the immunosuppressive tumor microenvironment. The present study provides an effective approach to destroy the metabolic network between cancer cells and CAFs and greatly improves the antitumor immune response by reducing lactate production, which serves as a promising strategy for combined chemo-immunotherapy mediated by glycolysis.

Cell membrane coated-nanoparticles for cancer immunotherapy

Cancer immunotherapy can effectively inhibit cancer progression by activating the autoimmune system, with low toxicity and high effectiveness. Some of cancer immunotherapy had positive effects on clinical cancer treatment. However, cancer immunotherapy is still restricted by cancer heterogeneity, immune cell disability, tumor immunosuppressive microenvironment and systemic immune toxicity. Cell membrane-coated nanoparticles (CMCNs) inherit abundant source cell-relevant functions, including “self” markers, cross-talking with the immune system, biological targeting, and homing to specific regions. These enable them to possess preferred characteristics, including better biological compatibility, weak immunogenicity, immune escaping, a prolonged circulation, and tumor targeting. Therefore, they are applied to precisely deliver drugs and promote the effect of cancer immunotherapy. In the review, we summarize the latest researches of biomimetic CMCNs for cancer immunotherapy, outline the existing specific cancer immune therapies, explore the unique functions and molecular mechanisms of various cell membrane-coated nanoparticles, and analyze the challenges which CMCNs face in clinical translation.

Tumor microenvironment based stimuli-responsive CRISPR/Cas delivery systems: A viable platform for interventional approaches

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) systems have emerged as robust tools in cancer gene therapy due to their simplicity and versatility. Nevertheless, the genome editing efficiency in tumor sites and the clinical applications of CRISPR/Cas have been compromised by non-specific delivery and genotoxicity. Recently, intelligent delivery systems incorporating sensitive materials in response to endogenous stimuli of the tumor microenvironment (TME) have represented viable platforms for tumor-specific genome editing and reduced side effects of CRISPR/Cas. Spurred by this promising direction, this review first introduces the CRISPR/Cas systems widely employed in cancer therapeutic explorations. Various types of CRISPR/Cas delivery systems sensitive to the stimuli in TME and typical dual-/multiple-responsive CRISPR/Cas carriers are further discussed, emphasizing the correlations between sensitive components and spatiotemporal delivery mechanisms. The genome editing efficiencies of CRISPR/Cas-loaded stimuli-responsive carriers are also summarized both in vitro and in vivo. Collectively, stimuli-responsive CRISPR/Cas delivery systems hold great promise for potent cancer gene therapy.

The Advances of Neutrophil-Derived Effective Drug Delivery Systems: A Key Review of Managing Tumors and Inflammation

The chimeric trait of recruitment by inflammatory signals endows neutrophils with the functionality of migrating to inflamed tissues, which can be utilized to tailor novel drug delivery systems. In this review, we introduce a mechanism of neutrophil-derived drug delivery systems recruited into inflamed sites and provide insight into tumors and inflammation therapy. In particular, the advantages of neutrophils—their endogenous-derived neutrophil membrane, exosomes as drug carriers for augmented targeting, prolonged circulation, and improved biostability—were concluded. Subsequently, the latest application in the treatment of tumors and inflammation was elaborated upon, followed by a discussion of the future prospects to neutrophil-derived delivery systems. This promising system will provide new therapeutic avenues for the treatment of inflammation and tumors.

Advances of nanomedicines in breast cancer metastasis treatment targeting different metastatic stages

Breast cancer is the most common tumor in women, and the metastasis further increases the malignancy with extremely high mortality. However, there is almost no effective method in the clinic to completely inhibit breast cancer metastasis due to the dynamic multistep process with complex pathways and scattered occurring site. Nowadays, nanomedicines have been evidenced with great potential in treating cancer metastasis. In this review, we summarize the latest research advances of nanomedicines in anti-metastasis treatment. Strategies are categorized according to the metastasis dynamics, including primary tumor, circulating tumor cells, pre-metastatic niches and secondary tumor. In each different stage of metastasis process, nanomedicines are designed specifically with different functions. At the end of the review, we give our perspectives on current limitations and future directions in anti-metastasis therapy. We expect the review provides comprehensive understandings of anti-metastasis therapy for breast cancer, and boosts the clinical translation in the future to improve women's health.

Simultaneous inhibition of breast cancer and its liver and lung metastasis by blocking inflammatory feed-forward loops

Inflammatory feed-forward loops including the steps of "inflammatory cell recruitment", "inflammatory signaling pathway activation" and "inflammatory factor production" are essential in the development of breast cancer and its metastasis. Herein, a doxorubicin-loaded micellar low-molecular-weight-heparin-astaxanthin nanoparticle (LMWH-AST/DOX, LA/DOX NP) was developed. The hydrophilic LMWH could decrease the recruitment of neutrophils in liver and myeloid-derived suppressor cells (MDSCs) in lung and tumor through P-selectin blockage. The hydrophobic AST could inhibit nuclear factor-κB (NF-κB) and signal transducer and activator of transcription 3 (STAT3) signaling pathways. Therefore, LA/DOX NPs could block these loops and suppress the liver metastasis by inhibiting the formation of neutrophil extracellular traps (NETs), inhibit the lung metastasis and alleviate the inflammatory and immunosuppressive microenvironment in tumor. This is the first functional nanoparticle reported to shut down inflammatory feed-forward loops and the formation of NETs, which provides a promising therapeutic strategy for breast cancer and its liver and lung metastasis.

Cannabidiol loaded extracellular vesicles sensitize triple-negative breast cancer to doxorubicin in both in-vitro and in vivo models

Extracellular Vesicles (EVs) were isolated from human umbilical cord mesenchymal stem cells (hUCMSCs) and were further encapsulated with cannabidiol (CBD) through sonication method (CBD EVs). CBD EVs displayed an average particle size of 114.1 ± 1.02 nm, zeta potential of -30.26 ± 0.12 mV, entrapment efficiency of 92.3 ± 2.21% and stability for several months at 4 °C. CBD release from the EVs was observed as 50.74 ± 2.44% and 53.99 ± 1.4% at pH 6.8 and pH 7.4, respectively after 48 h. Our in-vitro studies demonstrated that CBD either alone or in EVs form significantly sensitized MDA-MB-231 cells to doxorubicin (DOX) (*P < 0.05). Flow cytometry and migration studies revealed that CBD EVs either alone or in combination with DOX induced G1 phase cell cycle arrest and decreased migration of MDA-MB-231 cells, respectively. CBD EVs and DOX combination significantly reduced tumor burden (***P < 0.001) in MDA-MB-231 xenograft tumor model. Western blotting and immunocytochemical analysis demonstrated that CBD EVs and DOX combination decreased the expression of proteins involved in inflammation, metastasis and increased the expression of proteins involved in apoptosis. CBD EVs and DOX combination will have profound clinical significance in not only decreasing the side effects but also increasing the therapeutic efficacy of DOX in TNBC.

Keratin-Based Nanoparticles with Tumor-Targeting and Cascade Catalytic Capabilities for the Combinational Oxidation Phototherapy of Breast Cancer

Photodynamic therapy (PDT) holds tantalizing prospects of a prominent cancer treatment strategy. However, its efficacy remains limited by virtue of the hypoxic tumor microenvironment and the inadequate tumor-targeted delivery of photosensitizers, and these can be further exacerbated by the lack of development of a well-controlled nitric oxide (NO) release system at the target site. Inspired by Chinese medicine, we propose a revealing new keratin application. Keratin has garnered attention as an NO generator; however, its oncological use has rarely been investigated. We hypothesized that the incorporation of a phenylboronic acid (PBA) targeting ligand/methylene blue (MB) photosensitizer with a keratin NO donor would facilitate precise tumor delivery, enhancing PDT. Herein, we demonstrated that MB@keratin/PBA/d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) nanoparticles (MB@KPTNPs) specifically targeted breast cancer cells and effectively suppressed their growth. Through MB-mediated biometabolism, the endocytic MB@KPTNPs produced a sufficient amount of intracellular NO that reduced the glutathione level while boosting the efficiency of PDT. A therapeutic combination of NO/PDT was therefore achieved, resulting in significant inhibition of both in vivo tumor growth and lung metastasis. These findings underscore the importance of utilizing keratin-based nanoparticles that simultaneously combine targeting of the tumor and self-generating NO with a cascading catalytic ability as a novel oxidation therapeutic strategy for enhancing PDT.

Augment the efficacy of eradicating metastatic lesions and tumor proliferation in breast cancer by honokiol-loaded pH-sensitive targeted lipid nanoparticles

Functionally-enabled delivery systems for aggressive lung metastases from breast cancer have been broadly examined, and the simultaneous inhibition of metastasis while fighting tumors persists as a provocative concern. We propose a valid strategy for delivering natural drugs-Honokiol (Hol) to achieve eradication of breast cancer cells and inhibition of pulmonary metastasis. A non-toxic degradable pH-sensitive polymer-PBAE for encapsulated Hol, and the outer layer was wrapped with Folate-DSPE-PEG₂₀₀₀ (FA/PBAE/Hol-NPs), which have strengthened stability, prolonged in vivo circulation time and efficiently targets tumor sites. FA/PBAE/Hol-NPs displayed dampening the capability of migration and invasion, elevated 4T1 uptake and boosted apoptosis. What's more, 4T1 breast cancer model mice exhibited marked anti-tumor (Inhibition rate of 62.8 %) and lung metastasis suppression (Inhibition rate of 84.3 %). In parallel, histological immunofluorescence and immunohistochemical assays demonstrate higher apoptosis levels and repression of matrix metalloproteinase expression in mice, all of which are instrumental in inhibiting lung metastasis. Taken together, FA/PBAE/Hol-NPs can as an efficacious intravenous drug delivery system for the curative treatment of metastatic breast cancer.