Gold Nanoparticles Induce Tumor Vessel Normalization and Impair Metastasis by Inhibiting Endothelial Smad2/3 Signaling

Targeting breast tumor extracellular matrix and stroma utilizing nanoparticles

Breast cancer is a complicated malignancy and is known as the most common cancer in women. Considerable experiments have been devoted to explore the basic impacts of the tumor stroma, particularly the extracellular matrix (ECM) and stromal components, on tumor growth and resistance to treatment. ECM is made up of an intricate system of proteins, glycosaminoglycans, and proteoglycans, and maintains structural support and controls key signaling pathways involved in breast tumors. ECM can block different drugs such as chemotherapy and immunotherapy drugs from entering the tumor stroma. Furthermore, the stromal elements, such as cancer-associated fibroblasts (CAFs), immune cells, and blood vessels, have crucial impacts on tumor development and therapeutic resistance. Recently, promising outcomes have been achieved in using nanotechnology for delivering drugs to tumor stroma and crossing ECM in breast malignancies. Nanoparticles have various benefits for targeting the breast tumor stroma, such as improved permeability and retention, extended circulation time, and the ability to actively target the area. This review covers the latest developments in nanoparticle therapies that focus on breast tumor ECM and stroma. We will explore different approaches using nanoparticles to target the delivery of anticancer drugs like chemotherapy, small molecule drugs, various antitumor products, and other specific synthetic therapeutic agents to the breast tumor stroma. Furthermore, we will investigate the utilization of nanoparticles in altering the stromal elements, such as reprogramming CAFs and immune cells, and also remodeling ECM.

Genetic and microenvironmental evolution of colorectal liver metastases under chemotherapy

Drug resistance limits the efficacy of chemotherapy for colorectal cancer liver metastasis (CRLM). However, the evolution of CRLM during drug treatment remains poorly elucidated. Multi-omics and treatment response data from 115 samples of 49 patients with CRLM undergoing bevacizumab (BVZ)-based chemotherapy show little difference in genomic alterations in 92% of cases, while remarkable differences are observed at the transcriptomic level. By decoupling intrinsic and acquired resistance, we find that hepatocyte and myeloid cell infiltration contribute to 38.5% and 23.1% of acquired resistance, respectively. Importantly, SMAD4 mutations and chr20q copy-number gain are associated with intrinsic chemoresistance. Gene interference experiments suggest that SMAD4R361H/C mutations confer BVZ and 5-fluorouracil (5-FU) resistance through STAT3 signaling. Notably, supplementing BVZ and 5-FU with the STAT3 inhibitor GB201 restores therapeutic efficacy in SMAD4R361H/C cancer cells. Our study uncovers the evolutionary dynamics of CRLM and its microenvironment during treatment and offers strategies to overcome drug resistance.

Targeted gold nanoparticles for ovarian cancer (Review)

Among all malignant gynecological tumors, ovarian cancer (OC) has the highest mortality rate. OC is often diagnosed at advanced and incurable stages; however, early diagnosis can enable the use of optimized and personalized treatments. Intensive research into the synthesis and characterization of gold nanoparticles (AuNPs) has been performed with the aim of developing innovative materials for use in biological and photothermal therapies for OC. AuNPs can be chemically modified and functionalized by binding to a variety of organic compounds and biomolecules, such as peptides, antibodies and therapeutic agents, via simple synthetic processes. They are particularly suitable for use as carriers for drug delivery. In the present review, the synthesis and characteristics of AuNPs are summarized, and their potential in OC therapy are discussed.

Personalized nanovaccines for treating solid cancer metastases

Cancer vaccines have garnered attention as a potential treatment for cancer metastases. Nevertheless, the clinical response rate to vaccines remains < 30%. Nanoparticles stabilize vaccines and improve antigen recognition and presentation, resulting in high tumor penetration or accumulation, effective co-distribution of drugs to the secondary lymphatic system, and adaptable antigen or adjuvant administration. Such vaccine-like nanomedicines have the ability to eradicate the primary tumors as well as to prevent or eliminate metastases. This review examines state-of-the-art nanocarriers developed to deliver tumor vaccines to metastases, including synthetic, semi-biogenic, and biogenic nanosystems. Moreover, it highlights the physical and pharmacological properties that enhance their anti-metastasis efficiency. This review also addresses the combination of nanovaccines with cancer immunotherapy to target various steps in the metastatic cascade, drawing insights from preclinical and clinical studies. The review concludes with a critical analysis of the challenges and frameworks linked to the clinical translation of cancer nanovaccines.

Hypoxia-induced Semaphorin 3A promotes the development of endometriosis through regulating macrophage polarization

BACKGROUND

Semaphorin 3A (Sema3A) is a member of neural guidance factor family well-known for inducing the collapse of nerve cell growth cone and regulating nerve redistribution. It also has been characterized as an immunoregulatory and tumor promoting factor. Our previous study showed that Sema3A was involved in the regulation of sympathetic innervation and neuropathic pain of endometriosis. Nevertheless, the role of Sema3A in the development of endometriosis and its potential upstreaming factor are still not clear.

METHODS

Histology experiments were carried to detect the expression of Sema3A, hypoxia -inducible factor 1α (HIF-1α) and the distribution of macrophages. Cell experiments were used to explore the effect of Sema3A on the proliferation and migration of endometrial stromal cells (ESCs) and to confirm the regulatory action of HIF-1α on Sema3A. In vivo experiments were carried out to explore the role of Sema3A on the development of endometriosis.

RESULTS

Sema3A was highly expressed in endometriotic lesions and could enhanced the proliferation and migration abilities of ESCs. Aberrant macrophage distribution was found in endometriotic lesions. Sema3A also promoted the differentiation of monocytes into anti-inflammatory macrophages, so indirectly mediating the proliferation and migration of ESCs. Hypoxic microenvironment induced Sema3A mRNA and protein expression in ESCs via HIF-1α. Administration of Sema3A promoted the development of endometriosis in a mouse model.

CONCLUSIONS

Sema3A, which is regulated by HIF-1α, is a promoting factor for the development of endometriosis. Targeting Sema3A may be a potential treatment strategy to control endometriotic lesions.

Advances in tumor vascular growth inhibition

Tumor growth and metastasis require neovascularization, which is dependent on a complex array of factors, such as the production of various pro-angiogenic factors by tumor cells, intercellular signaling, and stromal remodeling. The hypoxic, acidic tumor microenvironment is not only conducive to tumor cell proliferation, but also disrupts the equilibrium of angiogenic factors, leading to vascular heterogeneity, which further promotes tumor development and metastasis. Anti-angiogenic strategies to inhibit tumor angiogenesis has, therefore, become an important focus for anti-tumor therapy. The traditional approach involves the use of anti-angiogenic drugs to inhibit tumor neovascularization by targeting upstream and downstream angiogenesis-related pathways or pro-angiogenic factors, thereby inhibiting tumor growth and metastasis. This review explores the mechanisms involved in tumor angiogenesis and summarizes currently used anti-angiogenic drugs, including monoclonal antibody, and small-molecule inhibitors, as well as the progress and challenges associated with their use in anti-tumor therapy. It also outlines the opportunities and challenges of treating tumors using more advanced anti-angiogenic strategies, such as immunotherapy and nanomaterials.

The potential of vascular normalization for sensitization to radiotherapy

Radiotherapy causes apoptosis mainly through direct or indirect damage to DNA via ionizing radiation, leading to DNA strand breaks. However, the efficacy of radiotherapy is attenuated in malignant tumor microenvironment (TME), such as hypoxia. Tumor vasculature, due to the imbalance of various angiogenic and anti-angiogenic factors, leads to irregular morphology of tumor neovasculature, disordered arrangement of endothelial cells, and too little peripheral coverage. This ultimately leads to a TME characterized by hypoxia, low pH and high interstitial pressure. This deleterious TME further exacerbates the adverse effects of tumor neovascularization and weakens the efficacy of conventional radiotherapy. Whereas normalization of blood vessels improves TME and thus the efficacy of radiotherapy. In addition to describing the research progress of radiotherapy sensitization and vascular normalization, this review focuses on the strategy and application prospect of modulating vascular normalization to improve the efficacy of radiotherapy sensitization.

N-Cadherin Targeted Melanin Nanoparticles Reverse the Endothelial-Mesenchymal Transition in Vascular Endothelial Cells to Potentially Slow the Progression of Atherosclerosis and Cancer

Endothelial-mesenchymal transition (EndoMT) of vascular endothelial cells has recently been considered as a key player in the early progression of a variety of vascular and nonvascular diseases, including atherosclerosis, cancer, and organ fibrosis. However, current strategies attempting to identify pharmacological inhibitors to block the regulatory pathways of EndoMT suffer from poor selectivity, unwanted side effects, and a heterogeneous response from endothelial cells with different origins. Furthermore, EndoMT inhibitors focus on preventing EndoMT, leaving the endothelial cells that have already undergone EndoMT unresolved. Here, we report the design of a simple but powerful nanoparticle system (i.e., N-cadherin targeted melanin nanoparticles) to convert cytokine-activated, mesenchymal-like endothelial cells back to their original endothelial phenotype. We term this process "Reversed EndoMT" (R-EndoMT). R-EndoMT allows the impaired endothelial barriers to recover their quiescence and intactness, with significantly reduced leukocyte and cancer cell adhesion and transmigration, which could potentially stop atheromatous plaque formation and cancer metastasis in the early stages. R-EndoMT is achieved on different endothelial cell types originating from arteries, veins, and capillaries, independent of activating cytokines. We reveal that N-cadherin targeted melanin nanoparticles reverse EndoMT by downregulating an N-cadherin dependent RhoA activation pathway. Overall, this approach offers a different prospect to treat multiple EndoMT-associated diseases by designing nanoparticles to reverse the phenotypical transition of endothelial cells.

Promising dawn in tumor microenvironment therapy: engineering oral bacteria

Despite decades of research, cancer continues to be a major global health concern. The human mouth appears to be a multiplicity of local environments communicating with other organs and causing diseases via microbes. Nowadays, the role of oral microbes in the development and progression of cancer has received increasing scrutiny. At the same time, bioengineering technology and nanotechnology is growing rapidly, in which the physiological activities of natural bacteria are modified to improve the therapeutic efficiency of cancers. These engineered bacteria were transformed to achieve directed genetic reprogramming, selective functional reorganization and precise control. In contrast to endotoxins produced by typical genetically modified bacteria, oral flora exhibits favorable biosafety characteristics. To outline the current cognitions upon oral microbes, engineered microbes and human cancers, related literatures were searched and reviewed based on the PubMed database. We focused on a number of oral microbes and related mechanisms associated with the tumor microenvironment, which involve in cancer occurrence and development. Whether engineering oral bacteria can be a possible application of cancer therapy is worth consideration. A deeper understanding of the relationship between engineered oral bacteria and cancer therapy may enhance our knowledge of tumor pathogenesis thus providing new insights and strategies for cancer prevention and treatment.

Current advances in modulating tumor hypoxia for enhanced therapeutic efficacy

Hypoxia is a common feature of most solid tumors, which promotes the proliferation, invasion, metastasis, and therapeutic resistance of tumors. Researchers have been developing advanced strategies and nanoplatforms to modulate tumor hypoxia to enhance therapeutic effects. A timely review of this rapidly developing research topic is therefore highly desirable. For this purpose, this review first introduces the impact of hypoxia on tumor development and therapeutic resistance in detail. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are also systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We provide a detailed discussion of the rationale and research progress of these strategies. Through a review of current trends, it is hoped that this comprehensive overview can provide new prospects for clinical application in tumor treatment. STATEMENT OF SIGNIFICANCE: As a common feature of most solid tumors, hypoxia significantly promotes tumor progression. Advanced nanoplatforms have been developed to modulate tumor hypoxia to enhanced therapeutic effects. In this review, we first introduce the impact of hypoxia on tumor progression. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We discuss the rationale and research progress of the above strategies in detail, and finally introduce future challenges for treatment of hypoxic tumors. By reviewing the current trends, this comprehensive overview can provide new prospects for clinical translatable tumor therapy.

Nanodelivery Systems as a Novel Strategy to Overcome Treatment Failure of Cancer

Despite the tremendous progress in cancer treatment in recent decades, cancers often become resistant due to multiple mechanisms, such as intrinsic or acquired multidrug resistance, which leads to unsatisfactory treatment effects or accompanying metastasis and recurrence, ultimately to treatment failure. With a deeper understanding of the molecular mechanisms of tumors, researchers have realized that treatment designs targeting tumor resistance mechanisms would be a promising strategy to break the therapeutic deadlock. Nanodelivery systems have excellent physicochemical properties, including highly efficient tissue-specific delivery, substantial specific surface area, and controllable surface chemistry, which endow nanodelivery systems with capabilities such as precise targeting, deep penetration, responsive drug release, multidrug codelivery, and multimodal synergy, which are currently widely used in biomedical researches and bring a new dawn for overcoming cancer resistance. Based on the mechanisms of tumor therapeutic resistance, this review summarizes the research progress of nanodelivery systems for overcoming tumor resistance to improve therapeutic efficacy in recent years and offers prospects and challenges of the application of nanodelivery systems for overcoming cancer resistance.

Progress on the pathological tissue microenvironment barrier-modulated nanomedicine

Imbalance in the tissue microenvironment is the main obstacle to drug delivery and distribution in the human body. Before penetrating the pathological tissue microenvironment to the target site, therapeutic agents are usually accompanied by three consumption steps: the first step is tissue physical barriers for prevention of their penetration, the second step is inactivation of them by biological molecules, and the third step is a cytoprotective mechanism for preventing them from functioning on specific subcellular organelles. However, recent studies in drug-hindering mainly focus on normal physiological rather than pathological microenvironment, and the repair of damaged physiological barriers is also rarely discussed. Actually, both the modulation of pathological barriers and the repair of damaged physiological barriers are essential in the disease treatment and the homeostasis maintenance. In this review, we present an overview describing the latest advances in the generality of these pathological barriers and barrier-modulated nanomedicine. Overall, this review holds considerable significance for guiding the design of nanomedicine to increase drug efficacy in the future.

Immunotherapies targeting tumor vasculature: challenges and opportunities

Angiogenesis is a hallmark of cancer biology, and neoadjuvant therapies targeting either tumor vasculature or VEGF signaling have been developed to treat solid malignant tumors. However, these therapies induce complete vascular depletion leading to hypoxic niche, drug resistance, and tumor recurrence rate or leading to impaired delivery of chemo drugs and immune cell infiltration at the tumor site. Achieving a balance between oxygenation and tumor growth inhibition requires determining vascular normalization after treatment with a low dose of antiangiogenic agents. However, monotherapy within the approved antiangiogenic agents' benefits only some tumors and their efficacy improvement could be achieved using immunotherapy and emerging nanocarriers as a clinical tool to optimize subsequent therapeutic regimens and reduce the need for a high dosage of chemo agents. More importantly, combined immunotherapies and nano-based delivery systems can prolong the normalization window while providing the advantages to address the current treatment challenges within antiangiogenic agents. This review summarizes the approved therapies targeting tumor angiogenesis, highlights the challenges and limitations of current therapies, and discusses how vascular normalization, immunotherapies, and nanomedicine could introduce the theranostic potentials to improve tumor management in future clinical settings.

Targeting endothelial permeability in the EPR effect

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

Awakening Allies for Breaking Microenvironment Barriers: NIR-II Guided Orthogonal Activation of Tumor-Infiltrating Mast Cells for Efficient Nano-Drug Delivery

Mast cells (MCs), powerful immune cells that heavily infiltrate cancer cells, play a crucial role in tumor formation. Activated MCs can release histamine and a family of proteases through degranulation effects, concurrently achieving endothelial junction weakening and stromal degradation of the tumor microenvironment, thereby clearing the obstacles for nano-drug infiltration. To achieve precise activation of tumor-infiltrating MCs, orthogonally excited rare earth nanoparticles (ORENP), with two channels, are introduced for the controllable stimulating drugs release wrapped in "photocut tape". The ORENP can emit near-infrared II (NIR-II) for image tracing for tumor localization in Channel 1 (808/NIR-II) and allows energy upconversion to emit ultraviolet (UV) light for releasing drugs for MCs stimulation in Channel 2 (980/UV). Finally, the combined use of chemical and cellular tools enables clinical nano-drugs to achieve a significant increase in tumor infiltration, thereby enhancing the efficacy of nano-chemotherapy.

Recent Advances in Nanoplatform Construction Strategy for Alleviating Tumor Hypoxia

Hypoxia is a typical feature of most solid tumors and has important effects on tumor cells' proliferation, invasion, and metastasis. This is the key factor that leads to poor efficacy of different kinds of therapy including chemotherapy, radiotherapy, photodynamic therapy, etc. In recent years, the construction of hypoxia-relieving functional nanoplatforms through nanotechnology has become a new strategy to reverse the current situation of tumor microenvironment hypoxia and improve the effectiveness of tumor treatment. Here, the main strategies and recent progress in constructing nanoplatforms are focused on to directly carry oxygen, generate oxygen in situ, inhibit mitochondrial respiration, and enhance blood perfusion to alleviate tumor hypoxia. The advantages and disadvantages of these nanoplatforms are compared. Meanwhile, nanoplatforms based on organic and inorganic substances are also summarized and classified. Through the comprehensive overview, it is hoped that the summary of these nanoplatforms for alleviating hypoxia could provide new enlightenment and prospects for the construction of nanomaterials in this field.

Overcoming tumor microenvironment obstacles: Current approaches for boosting nanodrug delivery

In order to achieve targeted delivery of anticancer drugs, efficacy improvement, and side effect reduction, various types of nanoparticles are employed. However, their therapeutic effects are not ideal. This phenomenon is caused by tumor microenvironment abnormalities such as abnormal blood vessels, elevated interstitial fluid pressure, and dense extracellular matrix that affect nanoparticle penetration into the tumor's interstitium. Furthermore, nanoparticle properties including size, charge, and shape affect nanoparticle transport into tumors. This review comprehensively goes over the factors hindering nanoparticle penetration into tumors and describes methods for improving nanoparticle distribution by remodeling the tumor microenvironment and optimizing nanoparticle physicochemical properties. Finally, a critical analysis of future development of nanodrug delivery in oncology is further discussed. STATEMENT OF SIGNIFICANCE: This article reviews the factors that hinder the distribution of nanoparticles in tumors, and describes existing methods and approaches for improving the tumor accumulation from the aspects of remodeling the tumor microenvironment and optimizing the properties of nanoparticles. The description of the existing methods and approaches is followed by highlighting their advantages and disadvantages and put forward possible directions for the future researches. At last, the challenges of improving tumor accumulation in nanomedicines design were also discussed. This review will be of great interest to the broad readers who are committed to delivering nanomedicine for cancer treatment.

Gold Nanoparticles: Construction for Drug Delivery and Application in Cancer Immunotherapy

Cancer immunotherapy is an innovative treatment strategy to enhance the ability of the immune system to recognize and eliminate cancer cells. However, dose limitations, low response rates, and adverse immune events pose significant challenges. To address these limitations, gold nanoparticles (AuNPs) have been explored as immunotherapeutic drug carriers owing to their stability, surface versatility, and excellent optical properties. This review provides an overview of the advanced synthesis routes for AuNPs and their utilization as drug carriers to improve precision therapies. The review also emphasises various aspects of AuNP-based immunotherapy, including drug loading, targeting strategies, and drug release mechanisms. The application of AuNPs combined with cancer immunotherapy and their therapeutic efficacy are briefly discussed. Overall, we aimed to provide a recent understanding of the advances, challenges, and prospects of AuNPs for anticancer applications.

Combat Against Gynecological Cancers with Blood Vessels as Entry Point: Anti-Angiogenic Drugs, Clinical Trials and Pre-Clinical Nano-Delivery Platforms

Angiogenesis is an essential mechanism for the progression of gynecological cancers. Although approved anti-angiogenic drugs have demonstrated clinical efficacy in treating gynecological cancers, the full potential of therapeutic strategies based on tumor blood vessels has not yet been realized. This review summarizes the latest angiogenesis mechanisms involved in the progression of gynecological cancers and discusses the current clinical practice of approved anti-angiogenic drugs and related clinical trials. Given the close relationship between gynecological cancers and blood vessels, we highlight more delicate strategies for regulating tumor vessels, including wise drug combinations and smart nano-delivery platforms to achieve highly efficient drug delivery and overall vessel microenvironment regulation. We also address current challenges and future opportunities in this field. We aim to generate interest in therapeutic strategies that target blood vessels as a key entry point and offer new potential and inspiration for combating gynecological cancers.

The application and research progress of anti-angiogenesis therapy in tumor immunotherapy

Tumor immunotherapy, as the focus of scientific research and clinical tumor treatment in recent years, has received extensive attention. Due to its remarkable curative effect and fewer side effects than traditional treatments, it has significant clinical benefits for the treatment of various advanced cancers and can improve cancer patient survival in the long term. Currently, most patients cannot benefit from immunotherapy, and some patients may experience tumor recurrence and drug resistance even if they achieve remission overcome. Numerous studies have shown that the abnormal angiogenesis state of tumors can lead to immunosuppressive tumor microenvironment, which affects the efficacy of immunotherapy. Actually, to improve the efficacy of immunotherapy, the application of anti-angiogenesis drugs to normalize abnormal tumor vessel has been widely confirmed in basic and clinical research. This review not only discusses the risk factors, mechanisms, and effects of abnormal and normalized tumor angiogenesis state on the immune environment, but summarizes the latest progress of immunotherapy combined with anti-angiogenic therapy. We hope this review provides an applied reference for anti-angiogenesis drugs and synergistic immunotherapy therapy.

Multifunctional nanostructures: Intelligent design to overcome biological barriers

Over the past three decades, nanoscience has offered a unique solution for reducing the systemic toxicity of chemotherapy drugs and for increasing drug therapeutic efficiency. However, the poor accumulation and pharmacokinetics of nanoparticles are some of the key reasons for their slow translation into the clinic. The is intimately linked to the non-biological nature of nanoparticles and the aberrant features of solid cancer, which together significantly compromise nanoparticle delivery. New findings on the unique properties of tumors and their interactions with nanoparticles and the human body suggest that, contrary to what was long-believed, tumor features may be more mirage than miracle, as the enhanced permeability and retention based efficacy is estimated to be as low as 1%. In this review, we highlight the current barriers and available solutions to pave the way for approved nanoformulations. Furthermore, we aim to discuss the main solutions to solve inefficient drug delivery with the use of nanobioengineering of nanocarriers and the tumor environment. Finally, we will discuss the suggested strategies to overcome two or more biological barriers with one nanocarrier. The variety of design formats, applications and implications of each of these methods will also be evaluated.

Nanomaterial-Based Antivascular Therapy in the Multimodal Treatment of Cancer

Abnormal tumor vasculature and a hypoxic tumor microenvironment (TME) limit the effectiveness of conventional cancer treatment. Recent studies have shown that antivascular strategies that focus on antagonizing the hypoxic TME and promoting vessel normalization effectively synergize to increase the antitumor efficacy of conventional therapeutic regimens. By integrating multiple therapeutic agents, well-designed nanomaterials exhibit great advantages in achieving higher drug delivery efficiency and can be used as multimodal therapy with reduced systemic toxicity. In this review, strategies for the nanomaterial-based administration of antivascular therapy combined with other common tumor treatments, including immunotherapy, chemotherapy, phototherapy, radiotherapy, and interventional therapy, are summarized. In particular, the administration of intravascular therapy and other therapies with the use of versatile nanodrugs is also described. This review provides a reference for the development of multifunctional nanotheranostic platforms for effective antivascular therapy in combined anticancer treatments.

Tumor microenvironment remodeling via targeted depletion of M2-like tumor-associated macrophages for cancer immunotherapy

M2-like tumor-associated macrophages (TAMs) typically exhibit numerous tumor-promoting properties. Reducing the abundance of M2-like TAMs would shed light on the relief of immunosuppressive tumor microenvironment (TME), activation of the host immune system, infiltration of CD8⁺ T cells into the TME and restoring the function of the infiltrating T cells, which collectively inhibits tumor growth. Therefore, targeted depletion of M2-like TAMs can be a promising immunotherapy approach. In this study, we rationally constructed an M2-like TAMs-targeted nanoliposome, which encapsulates zoledronic acid (ZA) in the core, loads hematoporphyrin monomethyl ether (HMME, a typical sonosensitizer) in the lipid bilayer, and modifies M2pep peptide (the targeting unit) on the surface (designated as M-H@lip-ZA). Our aim is to validate the effectiveness of M-H@lip-ZA nanoliposomes to remodel TME via targeted depletion of M2-like TAMs for cancer immunotherapy. Through the M2pep peptide, M-H@lip-ZA can be efficiently delivered to M2-like TAMs. In the meantime, reactive oxygen species (ROS) resulting from sonodynamic therapy (SDT), together with inner ZA that shows high affinity and cytotoxicity to TAMs, can effectively deplete M2-like TAMs and remodel TME (normalize tumor vasculatures, strengthen intertumoral perfusion, ease tumor hypoxia, increase immune-promoting cytokines and decrease immunosuppressive cytokines). The tumor growth can be effectively inhibited. This work proposed a new paradigm for cancer immunotherapy via targeted depletion of M2-like TAMs. STATEMENT OF SIGNIFICANCE: • M2-like TAMs-targeted nanoliposome (M-H@lip-ZA) was designed and prepared. • Sonodynamic therapy (SDT), together with zoledronic acid (ZA) that shows high affinity and cytotoxicity to tumor-associated macrophages (TAMs), can effectively deplete M2-like TAMs. Subsequently, immune-promoting tumor microenvironment (TME) can be formed, which includes normalized tumor vasculatures, enhanced intertumoral perfusion, relieved tumor hypoxia, increased immune-promoting cytokines, and decreased immunosuppressive cytokines. • The targeted depletion of M2-like TAMs is a promising cancer immunotherapy approach.

Bacterial-Mediated Tumor Therapy: Old Treatment in a New Context

Targeted therapy and immunotherapy have brought hopes for precision cancer treatment. However, complex physiological barriers and tumor immunosuppression result in poor efficacy, side effects, and resistance to antitumor therapies. Bacteria-mediated antitumor therapy provides new options to address these challenges. Thanks to their special characteristics, bacteria have excellent ability to destroy tumor cells from the inside and induce innate and adaptive antitumor immune responses. Furthermore, bacterial components, including bacterial vesicles, spores, toxins, metabolites, and other active substances, similarly inherit their unique targeting properties and antitumor capabilities. Bacteria and their accessory products can even be reprogrammed to produce and deliver antitumor agents according to clinical needs. This review first discusses the role of different bacteria in the development of tumorigenesis and the latest advances in bacteria-based delivery platforms and the existing obstacles for application. Moreover, the prospect and challenges of clinical transformation of engineered bacteria are also summarized.

Gold nanoparticles inhibit tumor growth via targeting the Warburg effect in a c-Myc-dependent way

Gold nanoparticles (AuNPs) are prospective tools for nano-based medicine that can directly target cellular biological processes to influence cell fate and function. Studies have revealed the essential role of AuNPs in metabolic remodeling for macrophage polarization. Nevertheless, as a hallmark of cancer cells, metabolic changes in tumor cells in response to AuNPs have not yet been reported. In the present study, polymer- and folate-conjugated AuNPs with satisfactory biocompatibility and tumor-targeting activity were synthesized to investigate their underlying roles in tumor metabolism. Tumor cells were significantly suppressed by AuNPs in vitro and in vivo, with little cytotoxicity in non-tumor cells. Subcellular localization showed that AuNPs localized in the mitochondria of tumor cells and impaired their structure and function, leading to excessive oxidative stress and mitochondrial apoptosis. Metabolic stress, with decreased glycolysis and insufficient nutrients, was also caused by AuNPs exposure in tumor cells. Mechanistically, the key enzymes (GLUT1 and HK2) for glycolysis modulation were remarkably reduced by AuNPs in a c-Myc-dependent manner. The present study demonstrated a new mechanism for AuNPs in the inhibition of tumor growth, that is, via directly targeting glycolysis and depriving energy. These findings provide new strategies for the design of nano-based medicines and anti-glycolytic therapeutics to inhibit the development of malignant tumors. STATEMENT OF SIGNIFICANCE: Gold nanoparticles (AuNPs) have acquired ever-increasing interest for applications in cancer treatment and diagnosis due to their high biosafety and facile surface modification. Recent studies have shown that AuNPs can work as active agents to directly target the cellular processes and harbor antitumor properties, while the underlying mechanisms remain largely unknown. From the present findings, the stabilized AuNPs showed direct inhibition effects on tumor growth by glycolysis inhibition and energy deprivation. These results provide new insights of AuNPs for tumor treatments, which will further contribute to the development of promising nano-based medicines and anti-glycolytic therapies.

Colon-targeted bacterial hydrogel for tumor vascular normalization and improved chemotherapy

The endogenous H₂S plays an important role in the occurrence and development of colon cancer, and is related to the abnormal blood vessels. Here, we reported on a sulfhydryl hyaluronid-based hydrogel (HA-SH) synthesized by amide reaction and further obtained a bacterial hydrogel by loading Thiobacillus denitrificans to the hydrogel for targeting adhesion to the colon. It was found that the loaded bacteria in HA-SH hydrogel can scavenge excess H₂S in colon cancer, then promote tumor vascular normalization and improve the delivery of chemotherapy drug CPT to inhibit tumor progression. Both in vivo and in vitro experiments show that the self-crosslinked bacterial hydrogel has satisfactory effects in inhibiting tumor progression and promoting tumor vascular normalization in colon cancer. This study presents an efficient method to target the colon and consume overexpressed H₂S in colon cancer to inhabit tumor progression, providing a new way for oral drug treatment of colon cancer.

HIF-1α inhibitor YC-1 suppresses triple-negative breast cancer growth and angiogenesis by targeting PlGF/VEGFR1-induced macrophage polarization

Triple negative breast cancer (TNBC) is an invasive and metastatic phenotype of breast cancer with limited treatment options. Published studies have demonstrated an inhibitory effect of HIF-α inhibition by its inhibitor YC-1 (lificiguat) on growth and angiogenesis of TNBC. However, the underlying mechanism remains poorly understood. In the current paper, our results show that HIF-1α inhibitor significantly inhibited TNBC growth by increasing cellular apoptosis and decreasing MVD, independent of a cell-autonomous mechanism in both endothelial and tumor cells. Genetic screening and in vivo experiments showed that a large number of M2-polarized TAMs accumulated in the hypoxic peri-necrotic region (PNR), where placental growth factor (PlGF) and its ligand, vascular endothelial growth factor receptor-1 (VEGFR-1) were upregulated. Furthermore, YC-1 skewed the polarization of TAMs away from M2 to M1 phenotype, therefore inhibiting TNBC angiogenesis and growth. This effect was further abrogated by VEGFR-1 neutralization and TAM depletion following clodronate liposome injection. These findings provide preclinical evidence for an indirect mechanism underlying YC-1-induced suppression of TNBC growth and angiogenesis, thereby offering a treatment option for TNBC.

Gold nanoparticles as antiangiogenic and antimetastatic agents

Angiogenesis and metastasis are two interdependent cancer hallmarks, the latter of which is the key cause of treatment failure. Thus, establishing effective antiangiogenesis/antimetastasis agents is the final frontier in cancer research. Gold nanoparticles (GNPs) may provide disruptive advancements in this regard due to their intrinsic physical and physiological features. Here, we comprehensively discuss recent potential therapeutical strategies to treat angiogenesis and metastasis and present a critical review on the state-of-the-art in vitro and in vivo evaluations of the antiangiogenic/antimetastatic activity of GNPs. Finally, we provide perspectives on the contribution of GNPs to the advancement of cancer management.

Nanomedicine embraces cancer radio-immunotherapy: mechanism, design, recent advances, and clinical translation

Cancer radio-immunotherapy, integrating external/internal radiation therapy with immuno-oncology treatments, emerges in the current management of cancer. A growing number of pre-clinical studies and clinical trials have recently validated the synergistic antitumor effect of radio-immunotherapy, far beyond the "abscopal effect", but it suffers from a low response rate and toxicity issues. To this end, nanomedicines with an optimized design have been introduced to improve cancer radio-immunotherapy. Specifically, these nanomedicines are elegantly prepared by incorporating tumor antigens, immuno- or radio-regulators, or biomarker-specific imaging agents into the corresponding optimized nanoformulations. Moreover, they contribute to inducing various biological effects, such as generating in situ vaccination, promoting immunogenic cell death, overcoming radiation resistance, reversing immunosuppression, as well as pre-stratifying patients and assessing therapeutic response or therapy-induced toxicity. Overall, this review aims to provide a comprehensive landscape of nanomedicine-assisted radio-immunotherapy. The underlying working principles and the corresponding design strategies for these nanomedicines are elaborated by following the concept of "from bench to clinic". Their state-of-the-art applications, concerns over their clinical translation, along with perspectives are covered.

Self-Therapeutic Nanomaterials: Applications in Biology and Medicine

Over past decades, nanotechnology has contributed to the biomedical field in areas including detection, diagnosis, and drug delivery via opto-electronic properties or enhancement of biological effects. Though generally considered inert delivery vehicles, a plethora of past and present evidence demonstrates that nanomaterials also exude unique intrinsic biological activity based on composition, shape, and surface functionalization. These intrinsic biological activities, termed self-therapeutic properties, take several forms, including mediation of cell-cell interactions, modulation of interactions between biomolecules, catalytic amplification of biochemical reactions, and alteration of biological signal transduction events. Moreover, study of biomolecule-nanomaterial interactions offers a promising avenue for uncovering the molecular mechanisms of biology and the evolution of disease. In this review, we observe the historical development, synthesis, and characterization of self-therapeutic nanomaterials. Next, we discuss nanomaterial interactions with biological systems, starting with administration and concluding with elimination. Finally, we apply this materials perspective to advances in intrinsic nanotherapies across the biomedical field, from cancer therapy to treatment of microbial infections and tissue regeneration. We conclude with a description of self-therapeutic nanomaterials in clinical trials and share our perspective on the direction of the field in upcoming years.

Recent Advancements in the Design of Nanodelivery Systems of siRNA for Cancer Therapy

RNA interference (RNAi) has increased the possibility of restoring RNA drug targets for cancer treatment. Small interfering RNA (siRNA) is a promising therapeutic RNAi tool that targets the defective gene by inhibiting its mRNA expression and stopping its translation. However, siRNAs have flaws like poor intracellular trafficking, RNase degradation, rapid kidney filtration, off-targeting, and toxicity, which limit their therapeutic efficiency. Nanocarriers (NCs) have been designed to overcome such flaws and increase antitumor activity. Combining siRNA and anticancer drugs can give synergistic effects in cancer cells, making them a significant gene-modification tool in cancer therapy. Our discussion of NCs-mediated siRNA delivery in this review includes their mechanism, limitations, and advantages in comparison with naked siRNA delivery. We will also discuss organic NCs (polymers and lipids) and inorganic NCs (quantum dots, carbon nanotubes, and gold) that have been reported for extensive delivery of therapeutic siRNA to tumor sites. Finally, we will conclude by discussing the studies based on organic and inorganic NCs-mediated siRNA drug delivery systems conducted in the years 2020 and 2021.

Recent advances of nanomaterial-based anti-angiogenic therapy in tumor vascular normalization and immunotherapy

Anti-angiogenesis therapy and immunotherapy are the first-line therapeutic strategies for various tumor treatments in the clinic, bringing significant advantages for tumor patients. Recent studies have shown that anti-angiogenic therapy can potentiate immunotherapy, with many clinical trials conducted based on the combination of anti-angiogenic agents and immune checkpoint inhibitors (ICIs). However, currently available clinical dosing strategies and tools are limited, emphasizing the need for more improvements. Although significant progress has been achieved, several big questions remained, such as how to achieve cell-specific targeting in the tumor microenvironment? How to improve drug delivery efficiency in tumors? Can nanotechnology be used to potentiate existing clinical drugs and achieve synergistic sensitization effects? Over the recent few years, nanomedicines have shown unique advantages in antitumor research, including cell-specific targeting, improved delivery potentiation, and photothermal effects. Given that the applications of nanomaterials in tumor immunotherapy have been widely reported, this review provides a comprehensive overview of research advances on nanomaterials in anti-angiogenesis therapy, mainly focusing on the immunosuppressive effects of abnormal tumor vessels in the tumor immune microenvironment, the targets and strategies of anti-angiogenesis nanomedicines, and the potential synergistic effects and molecular mechanisms of anti-angiogenic nanomedicines in combination with immunotherapy, ultimately providing new perspectives on the nanomedicine-based synergy between anti-angiogenic and immunotherapy.

Manipulation of the crosstalk between tumor angiogenesis and immunosuppression in the tumor microenvironment: Insight into the combination therapy of anti-angiogenesis and immune checkpoint blockade

Immunotherapy has been recognized as an effective and important therapeutic modality for multiple types of cancer. Nevertheless, it has been increasing recognized that clinical benefits of immunotherapy are less than expected as evidenced by the fact that only a small population of cancer patients respond favorably to immunotherapy. The structurally and functionally abnormal tumor vasculature is a hallmark of most solid tumors and contributes to an immunosuppressive microenvironment, which poses a major challenge to immunotherapy. In turn, multiple immune cell subsets have profound consequences on promoting neovascularization. Vascular normalization, a promising anti-angiogenic strategy, can enhance vascular perfusion and promote the infiltration of immune effector cells into tumors via correcting aberrant tumor blood vessels, resulting in the potentiation of immunotherapy. More interestingly, immunotherapies are prone to boost the efficacy of various anti-angiogenic therapies and/or promote the morphological and functional alterations in tumor vasculature. Therefore, immune reprograming and vascular normalization appear to be reciprocally regulated. In this review, we mainly summarize how tumor vasculature propels an immunosuppressive phenotype and how innate and adaptive immune cells modulate angiogenesis during tumor progression. We further highlight recent advances of anti-angiogenic immunotherapies in preclinical and clinical settings to solidify the concept that targeting both tumor blood vessels and immune suppressive cells provides an efficacious approach for the treatment of cancer.

Bridging wounds: tissue adhesives' essential mechanisms, synthesis and characterization, bioinspired adhesives and future perspectives

Bioadhesives act as a bridge in wound closure by forming an effective interface to protect against liquid and gas leakage and aid the stoppage of bleeding. To their credit, tissue adhesives have made an indelible impact on almost all wound-related surgeries. Their unique properties include minimal damage to tissues, low chance of infection, ease of use and short wound-closure time. In contrast, classic closures, like suturing and stapling, exhibit potential additional complications with long operation times and undesirable inflammatory responses. Although tremendous progress has been made in the development of tissue adhesives, they are not yet ideal. Therefore, highlighting and summarizing existing adhesive designs and synthesis, and comparing the different products will contribute to future development. This review first provides a summary of current commercial traditional tissue adhesives. Then, based on adhesion interaction mechanisms, the tissue adhesives are categorized into three main types: adhesive patches that bind molecularly with tissue, tissue-stitching adhesives based on pre-polymer or precursor solutions, and bioinspired or biomimetic tissue adhesives. Their specific adhesion mechanisms, properties and related applications are discussed. The adhesion mechanisms of commercial traditional adhesives as well as their limitations and shortcomings are also reviewed. Finally, we also discuss the future perspectives of tissue adhesives.

Metal-Polymer Nanoconjugates Application in Cancer Imaging and Therapy

Metallic-based nanoparticles present a unique set of physicochemical properties that support their application in different fields, such as electronics, medical diagnostics, and therapeutics. Particularly, in cancer therapy, the plasmonic resonance, magnetic behavior, X-ray attenuation, and radical oxygen species generation capacity displayed by metallic nanoparticles make them highly promising theragnostic solutions. Nevertheless, metallic-based nanoparticles are often associated with some toxicological issues, lack of colloidal stability, and establishment of off-target interactions. Therefore, researchers have been exploiting the combination of metallic nanoparticles with other materials, inorganic (e.g., silica) and/or organic (e.g., polymers). In terms of biological performance, metal-polymer conjugation can be advantageous for improving biocompatibility, colloidal stability, and tumor specificity. In this review, the application of metallic-polymer nanoconjugates/nanohybrids as a multifunctional all-in-one solution for cancer therapy will be summarized, focusing on the physicochemical properties that make metallic nanomaterials capable of acting as imaging and/or therapeutic agents. Then, an overview of the main advantages of metal-polymer conjugation as well as the most common structural arrangements will be provided. Moreover, the application of metallic-polymer nanoconjugates/nanohybrids made of gold, iron, copper, and other metals in cancer therapy will be discussed, in addition to an outlook of the current solution in clinical trials.

Remodeling of tumor microenvironment for enhanced tumor chemodynamic/photothermal/chemo-therapy

The anticancer treatment is largely affected by the microenvironment of the tumors, which not only resists the tumors to the thermo/chemo-therapy, but also promotes their growth and invasion. In this work, the angiogenesis factor is balanced by combining with the breathing hyperoxygen, for regulating the tumor microenvironment and also for relieving hypoxia and high tissue interstitial pressure, which promote drug delivery to tumor tissues by increasing the in vivo perfusion and reversing the immunosuppressive tumor. In addition, the designed multifunctional nanoparticles have a great potential for applications to the tumor dual-mode imaging including magnetic resonance (MR) and photoacoustic (PA) imaging. This work proposes a promising strategy to enhance the thermo/chemo-therapy efficacy by remodeling the tumor microenvironment, which would provide an alternative to prolong the lifetime of tumor patients.

The mechanistic immunosuppressive role of the tumour vasculature and potential nanoparticle-mediated therapeutic strategies

The tumour vasculature is well-established to display irregular structure and hierarchy that is conducive to promoting tumour growth and metastasis while maintaining immunosuppression. As tumours grow, their metabolic rate increases while their distance from blood vessels furthers, generating a hypoxic and acidic tumour microenvironment. Consequently, cancer cells upregulate the expression of pro-angiogenic factors which propagate aberrant blood vessel formation. This generates atypical vascular features that reduce chemotherapy, radiotherapy, and immunotherapy efficacy. Therefore, the development of therapies aiming to restore the vasculature to a functional state remains a necessary research target. Many anti-angiogenic therapies aim to target this such as bevacizumab or sunitinib but have shown variable efficacy in solid tumours due to intrinsic or acquired resistance. Therefore, novel therapeutic strategies such as combination therapies and nanotechnology-mediated therapies may provide alternatives to overcoming the barriers generated by the tumour vasculature. This review summarises the mechanisms that induce abnormal tumour angiogenesis and how the vasculature’s features elicit immunosuppression. Furthermore, the review explores examples of treatment regiments that target the tumour vasculature.

Overcoming Vascular Barriers to Improve the Theranostic Outcomes of Nanomedicines

Nanotheranostics aims to utilize nanomaterials to prevent, diagnose, and treat diseases to improve the quality of patients' lives. Blood vessels are responsible to deliver nutrients and oxygen to the whole body, eliminate waste, and provide access for patrolling immune cells for healthy tissues. Meanwhile, they can also nourish disease tissues, spread disease factors or cells into other healthy tissues, and deliver nanotheranostic agents to cover all the regions of a disease tissue. Thus, blood vessels are the first and the most important barrier for highly efficient nanotheranostics. Here, the structure and function of blood vessels are explored and how these characteristics affect nanotheranostics is discussed. Moreover, new mechanisms and related strategies about overcoming vascular obstacles for improved nanotheranostic outcomes are critically summarized, and their merits and demerits of each strategy are analyzed. Moreover, the present challenges to completely exhibit the potential of overcoming vascular barriers to improve the theranostic outcomes of nanomedicines in life science are also discussed. Finally, the future perspective is further discussed.

Multifunctional DNAzyme-Anchored Metal-Organic Framework for Efficient Suppression of Tumor Metastasis

High mortality and rapid development of metastasis requires the development of more effective antimetastasis strategies. However, conventional therapeutic methods, including surgery, radiation therapy, and chemotherapy, show less effectiveness in curbing the metastatic spread of cancer cells and the formation of metastases. A therapeutic platform, targeting the early stage of metastasis cascade, could effectively prevent metastasis dissemination. Herein, Fe/Mn-based metal-organic frameworks (FMM) were constructed for the delivery of a specific DNAzyme with high catalytic cleavage activity on the metastasis-involved Twist mRNA, thus efficiently inhibiting the invasion of cancer cells through DNAzyme-catalyzed gene silencing. Highly potent combined gene/chemodynamic therapy is achieved from the self-supplied DNAzyme cofactors and efficient glutathione depletion. Importantly, by virtue of the intrinsic photo-to-thermal conversion of the FMM nanocarriers, our combined therapeutic strategy could be further promoted under photothermal stimuli to speed up the Fenton reaction and to accelerate the release of the Twist DNAzyme with efficient gene therapy. Consequently, the effective elimination of tumors and the blockage of metastasis are simultaneously achieved under photothermal/magnetic resonance imaging guidance. This work aims at developing versatile theranostic agents to combat metastatic tumors.

Intelligent Nanodelivery System-Generated 1 O2 Mediates Tumor Vessel Normalization by Activating Endothelial TRPV4-eNOS Signaling

Tumor microenvironment (TME)-responsive intelligent photodynamic therapy (PDT) systems have attracted increasing interest in anticancer therapy, due to their potential to address significant and unsatisfactory therapeutic issues, such as limited tissue penetration, inevitable normal tissue damage, and excessive impaired vessels. Here, an H₂ O₂ -triggered intelligent LCL/ZnO PDT nanodelivery system is elaborately designed. LCL/ZnO can selectively regulate tumor-derived endothelial cells (TECs) and specifically kill tumor cells, by responding to different H₂ O₂ gradients in TECs and tumor cells. The LCL/ZnO is able to normalize tumor vessels, thereby resulting in decreased metastases, and ameliorating the immunosuppressive TME. Further analysis demonstrates that singlet oxygen (¹ O₂ )-activated transient receptor potential vanilloid-4-endothelial nitric oxide synthase signals generated in TECs by LCL/ZnO induce tumor vascular normalization, which is identified as a novel mechanism contributing to the increased ability of PDT to promote cancer therapy. In conclusion, designing an intelligent PDT nanodelivery system response to the TME, that includes both selective TECs regulation and specific tumor-killing, will facilitate the development of effective interventions for future clinical applications.

Recent Advances in KEAP1/NRF2-Targeting Strategies by Phytochemical Antioxidants, Nanoparticles, and Biocompatible Scaffolds for the Treatment of Diabetic Cardiovascular Complications

Significance: Modulation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-mediated antioxidant response is a key aspect in the onset of diabetes-related cardiovascular complications. With this review, we provide an overview of the recent advances made in the development of Nrf2-targeting strategies for the treatment of diabetes, with particular attention toward the activation of Nrf2 by natural antioxidant compounds, nanoparticles, and oxidative stress-modulating biocompatible scaffolds. Recent Advances: In the past 30 years, studies addressing the use of antioxidant therapies to treat diabetes have grown exponentially, showing promising but yet inconclusive results. Animal studies and clinical trials on the Nrf2 pathway have shown promising results, suggesting that its activation can delay or reverse some of the cardiovascular impairments in diabetes. Critical Issues: Hyperglycemia- and oscillating glucose levels-induced reactive oxygen species (ROS) accumulation is progressively emerging as a central factor in the onset and progression of diabetes-related cardiovascular complications, including endothelial dysfunction, retinopathy, heart failure, stroke, critical limb ischemia, ulcers, and delayed wound healing. In this context, accumulating evidence suggests a central role for Nrf2-mediated antioxidant response, one of the most studied cellular defensive mechanisms against ROS accumulation. Future Directions: Innovative approaches such as tissue engineering and nanotechnology are converging toward targeting oxidative stress in diabetes. Antioxid. Redox Signal. 36, 707-728.

Metastasis prevention: targeting causes and roots

The spread of tumor cells from the primary focus, metastasis, is the main cause of cancer mortality. Therefore, anticancer therapy should be focused on the prevention of metastatic disease. Key targets can be conditions in the primary tumor that are favorable for the appearance of metastatic cells and the first steps of the metastatic cascade. Here, we discuss different approaches for targeting metastasis causes (hypoxia, metabolism changes, and tumor microenvironment) and roots (angiogenesis, epithelial-mesenchymal transition, migration, and invasion). Also, we emphasize the challenges of the existing approaches for metastasis prevention and suggest opportunities to overcome them. In conclusion, we highlight the importance of clinical evaluation of the agents showing antimetastatic effects in vivo, especially in patients with early-stage cancers, the identification of metastatic seeds, and the development of therapeutics for their eradication.

Exosome-mediated delivery of transforming growth factor-β receptor 1 kinase inhibitors and toll-like receptor 7/8 agonists for combination therapy of tumors

In this study, combination therapy with the transforming growth factor-β receptor I (TGFβRI) kinase inhibitor SD-208 and a toll-like receptor (TLR)-7/8 agonist resiquimod (R848) was examined along with serum-derived exosomes (EXOs) as versatile carriers. SD-208-encapsulated EXOs (SD-208/EXOs) and R848-encapsulated EXOs (R848/EXOs) were successfully prepared with a size of 87 ± 8 nm and 51 ± 4 nm, respectively, which were stable in aqueous solution at pH 7.4. SD-208/EXOs and R848/EXOs reduced the migration of cancer cells (B16F10 and PC-3) and triggered the release of proinflammatory cytokines from stimulated macrophages and dendritic cells, respectively. The fluorescent dye-labeled EXOs showed significantly improved penetration through the PC-3/fibroblast co-culture spheroids and enhanced accumulation in the B16F10 mouse tumor model compared with the free fluorescent dye. In addition, the combination therapy of R848/EXOs (R848 dose of 0.36 mg/kg) and SD-208/EXOs (SD-208 dose of 0.75 mg/kg) reduced tumor growth and improved survival rate at low doses in the B16F10 tumor xenograft model. Taken together, the combination therapy using the TGFβRI kinase inhibitor and TLR 7/8 agonist with EXOs may serve as a promising strategy to treat melanoma and prostate cancer. STATEMENT OF SIGNIFICANCE: Owing to the prevalence of several non-responding cancers that resist treatment, it is necessary to identify a novel combined treatment strategy with biomaterials to maximize therapeutic efficacy and minimize the undesirable side effects. In this study, we aimed to examine the use of the TGFβRI kinase inhibitor SD-208 and the TLR7/8 agonist resiquimod (R848) encapsulated within serum-derived EXOs for their synergistic antitumor effects. We first demonstrated that combined treatment with SD-208 and R848 can be a convincing strategy to circumvent tumor growth in vivo using serum-derived exosomes as promising carriers. Therefore, we believe this manuscript would be of great interest to the biomaterial communities especially who are studying immunotherapy.

Facile synthesis of near-infrared responsive on-demand oxygen releasing nanoplatform for precise MRI-guided theranostics of hypoxia-induced tumor chemoresistance and metastasis in triple negative breast cancer

BACKGROUND

Hypoxia is an important factor that contributes to chemoresistance and metastasis in triple negative breast cancer (TNBC), and alleviating hypoxia microenvironment can enhance the anti-tumor efficacy and also inhibit tumor invasion.

METHODS

A near-infrared (NIR) responsive on-demand oxygen releasing nanoplatform (O2-PPSiI) was successfully synthesized by a two-stage self-assembly process to overcome the hypoxia-induced tumor chemoresistance and metastasis. We embedded drug-loaded poly (lactic-co-glycolic acid) cores into an ultrathin silica shell attached with paramagnetic Gd-DTPA to develop a Magnetic Resonance Imaging (MRI)-guided NIR-responsive on-demand drug releasing nanosystem, where indocyanine green was used as a photothermal converter to trigger the oxygen and drug release under NIR irradiation.

RESULTS

The near-infrared responsive on-demand oxygen releasing nanoplatform O2-PPSiI was chemically synthesized in this study by a two-stage self-assembly process, which could deliver oxygen and release it under NIR irradiation to relieve hypoxia, improving the therapeutic effect of chemotherapy and suppressed tumor metastasis. This smart design achieves the following advantages: (i) the O2 in this nanosystem can be precisely released by an NIR-responsive silica shell rupture; (ii) the dynamic biodistribution process of O2-PPSiI was monitored in real-time and quantitatively analyzed via sensitive MR imaging of the tumor; (iii) O2-PPSiI could alleviate tumor hypoxia by releasing O2 within the tumor upon NIR laser excitation; (iv) The migration and invasion abilities of the TNBC tumor were weakened by inhibiting the process of EMT as a result of the synergistic therapy of NIR-triggered O2-PPSiI.

CONCLUSIONS

Our work proposes a smart tactic guided by MRI and presents a valid approach for the reasonable design of NIR-responsive on-demand drug-releasing nanomedicine systems for precise theranostics in TNBC.

Nintedanib enhances the efficacy of PD-L1 blockade by upregulating MHC-I and PD-L1 expression in tumor cells

Background: Immune checkpoint inhibitors (ICIs), such as programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1), have been widely applied in clinical and scientific research. Despite their effective antitumor effects in clinical tumor therapy, most tumors are still resistant to ICIs and long-term benefits are lacking. In addition, tumor patients complicated with interstitial lung disease limit the application of ICI therapy. Therefore, for these cases, there is an urgent need to develop new methods to relieve lung complications and enhance the efficacy of ICI therapy. Nintedanib, a potent triple angiokinase inhibitor approved for the treatment of progressive fibrotic interstitial lung disease. However, its immunotherapy synergy properties and mechanism are still pending further exploration. Methods: To explore the therapeutic potential of nintedanib and αPD-L1 combination therapy, MC38, LLC, and 4T1 tumor models were used to investigate antitumor and antimetastatic activities in vivo. An idiopathic pulmonary fibrosis-tumor bearing model was used to evaluate the effect of the synergy therapy on tumor model complicated with lung disease. Moreover, RNA-seq, immunohistochemistry, and flow cytometry were utilized to analyze the effect of combination treatment on the tumor microenvironment. The bioactivity following different treatments was determined by western blotting, CCK-8, and flow cytometry. Results: In this study, nintedanib and αPD-L1 synergy therapy exhibited significant antitumor, antimetastatic and anti-pulmonary fibrosis effects. Both in vitro and in vivo experiments revealed that these effects included promoting vessel normalization, increasing infiltration and activation of immune cells in tumors, enhancing the response of interferon-gamma, and activating the MHC class I-mediated antigen presentation process. Moreover, our results showed an increased expression of PD-L1 and promoted phosphorylation of STAT3 after nintedanib (1 µM) treatment. Conclusion: The combination of nintedanib and αPD-L1 increased ICI therapy responses, relieved lung complications and further activated the tumor immune microenvironment; thus, exhibiting a notable antitumor effect. Accordingly, the nintedanib synergy strategy is expected to be a promising candidate therapy for tumor patients complicated with interstitial lung disease in clinical practice.

Recent advances of nanotechnology-based tumor vessel-targeting strategies

Tumor vessels can provide oxygen and nutrition for solid tumor tissue, create abnormal tumor microenvironment (TME), and play a vital role in the development, immune escape, metastasis and drug resistance of tumor. Tumor vessel-targeting therapy has become an important and promising direction in anti-tumor therapy, with the development of five anti-tumor therapeutic strategies, including vascular disruption, anti-angiogenesis, vascular blockade, vascular normalization and breaking immunosuppressive TME. However, the insufficient drug accumulation and severe side effects of vessel-targeting drugs limit their development in clinical application. Nanotechnology offers an excellent platform with flexible modified surface that can precisely deliver diverse cargoes, optimize efficacy, reduce side effects, and realize the combined therapy. Various nanomedicines (NMs) have been developed to target abnormal tumor vessels and specific TME to achieve more efficient vessel-targeting therapy. The article reviews tumor vascular abnormalities and the resulting abnormal microenvironment, the application of NMs in the tumor vessel-targeting strategies, and how NMs can improve these strategies and achieve multi-strategies combination to maximize anti-tumor effects.

Tumor vasculature-targeting nanomedicines

Uncontrolled tumor growth and subsequent distant metastasis are highly dependent on an adequate nutrient supply from tumor blood vessels, which have relatively different pathophysiological characteristics from those of normal vasculature. Obviously, strategies targeting tumor vasculature, such as anti-angiogenic drugs and vascular disrupting agents, are attractive methods for cancer therapy. However, the off-target effects and high dose administration of these drug regimens critically restrict their clinical applications. In recent years, nanomedicines focused on tumor vasculature have been shown to be superior to traditional therapeutic methods and do not induce side effects. This review will first highlight the recent development of tumor vasculature-targeting nanomedicines from the following four aspects: 1) angiogenesis-inhibiting nanomedicines (AINs); 2) vasculature-disrupting nanomedicines (VDNs); 3) vasculature infarction nanomedicines (VINs); and 4) vasculature-regulating nanomedicines (VRNs). Furthermore, the design principles, limitations, and future directions are also discussed. STATEMENT OF SIGNIFICANCE: Based on the essential roles of tumor blood vessels, the therapeutic strategies targeting tumor vasculature have exhibited good clinical therapeutic outcomes. However, poor patient adherence to free drug administration limits their clinical usage. Nanomedicines have great potential to overcome the abovementioned obstacle. This review summarizes the tumor-vasculature targeting nanomedicines from four aspects: 1) angiogenesis-inhibiting nanomedicines (AINs); 2) vasculature-disrupting nanomedicines (VDNs); 3) vasculature infarction nanomedicines (VINs); and 4) vasculature regulating nanomedicines (VRNs). In addition, this review provides perspectives on this research field.

Establishment of a 3D model of tumor-driven angiogenesis to study the effects of anti-angiogenic drugs on pericyte recruitment

Hepatocellular carcinoma (HCC), as a well-vascularized tumor, has attracted increasing attention in antiangiogenic therapies. Notably, emerging studies reveal that the long-term administration of antiangiogenic drugs induces hypoxia in tumors. Pericytes, which play a vital role in vascular stabilization and maturation, have been documented to be associated with antiangiogenic drug-induced tumor hypoxia. However, the role of antiangiogenic agents in regulating pericyte behavior still remains elusive. In this study, by using immunostaining analysis, we first demonstrated that tumors obtained from HCC patients were highly angiogenic, in which vessels were irregularly covered by pericytes. Therefore, we established a new 3D model of tumor-driven angiogenesis by culturing endothelial cells, pericytes, cancer stem cells (CSCs) and mesenchymal stem cells (MSCs) with microcarriers in order to investigate the effects and mechanisms exerted by antiangiogenic agents on pericyte recruitment during tumor angiogenesis. Interestingly, microcarriers, as supporting matrices, enhanced the interactions between tumor cells and the extracellular matrix (ECM), promoted malignancy of tumor cells and increased tumor angiogenesis within the 3D model, as determined by qRT-PCR and immunostaining. More importantly, we showed that zoledronic acid (ZA) reversed the inhibited pericyte recruitment, which was induced by sorafenib (Sora) treatment, through fostering the expression and activation of ErbB1/ErbB2 and PDGFR-β in pericytes, in both an in vitro 3D model and an in vivo xenograft HCC mouse model. Hence, our model provides a more pathophysiologically relevant platform for the assessment of therapeutic effects of antiangiogenic compounds and identification of novel pharmacological targets, which might efficiently improve the benefits of antiangiogenic treatment for HCC patients.