Enzyme responsiveness enhances the specificity and effectiveness of nanoparticles for the treatment of B16F10 melanoma

A novel pH-sensitive nanoparticles encapsulating anti-PD-1 antibody and MDK-siRNA overcome immune checkpoint blockade resistance in HCC via reshaping immunosuppressive TME

OBJECTIVE

Immunotherapy, notably the immune checkpoint blockade (ICB), has demonstrated significant promise in the management of diverse neoplasms. However, the PD-1 inhibitor has exhibited suboptimal objective response rates and did not achieve the primary endpoints in hepatocellular carcinoma (HCC) patients, primarily due to resistance to ICB fostered by the immunosuppressive tumor microenvironment (TME). To address ICI resistance and minimize adverse effects, we have engineered an innovative tumor-specific nanomedicine for the concurrent administration of aPD-1 and MDK-siRNA.

METHODS

Both in vitro and orthotopic HCC models were employed to investigate and establish the efficacy of the novel tumor-specific nanomedicine in overcoming the immunosuppressive TME. Specifically, the impact of the nanomedicine on the M2 polarization and polyamine metabolism within tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) was delineated. The immunomodulatory and antitumor effects, along with the side effects, of the nanomedicine integrating both aPD-1 and MDK-siRNA were assessed.

RESULTS

A dual pH-responsive nanomedicine was successfully fabricated to co-deliver MDK-siRNA and aPD-1. The nanomedicine achieved targeted drug delivery to tumors by engaging with circulating PD-1+ T cells and accompanying their migration into the tumor mass. Additionally, nanomedicine promoted efficient drug release within the acidic TME, deploying aPD-1 for ICI therapy and retaining MDK-siRNA-encapsulated nanomedicine to regulate TAMs and MDSCs synergistically. The synergistic application of MDK-siRNA and aPD-1, coupled with the efficient tumor-targeted drug delivery, potently suppressed M2 polarization and polyamine metabolism in TAMs and MDSCs, thereby overcoming the immunosuppressive TME and leading to significant therapeutic efficacy with minimal side effects in HCC.

CONCLUSION

We have developed an innovative tumor-specific nanocarrier for the co-delivery of aPD-1 and MDK-siRNA. We validated that the synthesized nanomedicine (aPD-1-siRNA@NP) yielded highly effective treatment and minimal side effects in both in vitro and orthotopic HCC models. Our work presents a nanomedicine-based approach for targeted dual-drug delivery, achieving notable efficacy in the treatment of HCC.

Innovative approach to the detection of circulating tumor biomarkers: multi-dimensional application of liposome technology

Malignant tumors represent a significant worldwide health challenge, with elevated morbidity and mortality rates necessitating enhanced early identification and individualized treatment. Liposomes, as biomimetic lipid-based nanovesicles, have developed as a multifaceted platform for detecting and treating malignant tumors due to their excellent biocompatibility, stability, and membrane fusion properties. Circulating tumor markers, such as circulating tumor cells (CTCs), extracellular vesicles (EVs), circulating tumor proteins (CTPs), and circulating tumor nucleic acids (ctNAs), play a key role in early cancer diagnosis, disease progression monitoring, and personalized therapy. Liposome-based platforms enable effective molecular recognition, targeted detection, and signal amplification by targeting circulating tumor biomarkers, significantly increasing the potential for early tumor diagnosis and treatment. This review systematically summarizes advancements in the study of liposomes concerning circulating tumor markers, including applications in targeted recognition, early detection, and disease diagnosis, while discussing present problems and prospective applications of existing technology.

Radiotherapy-derived engineered stem cell exosomes improve anti-glioma immunotherapy by promoting the formation of tertiary lymphoid structure and improve the release of type I interferon

The absence of signaling pathways related to intrinsic immune activation in tumor cells and the immunosuppressive microenvironment limit lymphocyte infiltration, constitutes an "immune-desert" tumor displaying insensitivity to various immunotherapies. This study investigates strategies to activate intrinsic immune pathways in glioma cells, reverse immunosuppression, and induce tertiary lymphoid structures (TLS) within the glioma microenvironment (GME) to enhance natural and adaptive immune responses. We successfully induced antigen-presenting cell activation, macrophage/microglia polarization, and TLS formation in GME by intracranial delivery of BafA1@Rexo-SC, which comprises exosomes from irradiated bone marrow-derived stem cells overexpressing CD47 nanobodies and STING, loaded with the autophagy inhibitor BafA1. These exosomes efficiently activated the cGAS-STING pathway, leading to the formation of "lymphoid tissue organizer cells (Lto)" cells, VEGFA release for high endothelial microvessel formation, and chemokine release for T and B cell recruitment. BafA1@Rexo-SC also promoted macrophage phagocytosis of tumor cells and enhanced effector T cell function by blocking CD47, while releasing type I interferon. Our findings suggest novel therapeutic approaches for glioma treatment.

Multifunctional glycyrrhizic acid-loaded nanoplatform combining ferroptosis induction and HMGB1 blockade for enhanced tumor immunotherapy

Inducing ferroptotic cell death has been recognized as a promising approach in cancer therapy. However, ferroptosis can provoke tumor infiltration by myeloid-derived suppressor cells (MDSCs) through HMGB1 secretion, causing a tumor suppressive immune response. On the other hand, ferroptosis also occurs the immune cells due to its non-selective properties, which can compromise anti-tumor immunity. To address these challenges, a two-pronged approach is proposed, encompassing selectively triggered ferroptosis in tumor cells and HMGB1 blockade, aimed at eliciting systemic anti-tumor immunity and alleviating immunosuppression. Herein, GSH-specific driven nanoplatform is composed of uniform FeOOH nanospindles coated with tetrasulfide bond-bridged mesoporous organosilica (DMOS) shell, and loaded with the HMGB1 inhibitor, glycyrrhizic acid (GA). This nanoplatform is endowed with high glutathione (GSH) depletion efficiency and exhibits highly efficient Fe2+ and ROS generation capacity, which promotes the accumulation of LPO and subsequently induces ferroptosis. Concurrently, the inhibition of HMGB1 release counteracts the immunosuppressive effects within the tumor microenvironment. This innovative nanoplatform effectively suppresses the growth of 4T1 tumors and notably enhancing the therapeutic outcomes of immune checkpoint blockade across experimental data. The collective findings indicate its potential as a reliable therapeutic strategy for boosting ferroptosis-mediated tumor immunity with favorable safety profiles.

MXene-based nanosheet for enhanced glioma therapy via photonic hyperthermia to boost the abscopal effect of radioimmunotherapy

Radiotherapy (RT) effectiveness is limited by low DNA damage in tumor cells, surrounding tissue harm, and tumor radioresistance with active DNA repair. Herein, we have engineered a two-dimensional nanomaterial consisting of MXene nanosheets at its core, coated with gold nanorods and a cisplatin shell, and further modified with polyvinyl alcohol, referred to as APMP. The APMP exploits its distinctive electronic properties and photothermal effects to augment radiosensitivity and impede DNA damage repair mechanisms. In vitro experiments demonstrate that APMP elevates reactive oxygen species (ROS) production to approximately 2.6 times higher than that achieved with radiotherapy alone, thereby significantly enhancing the sensitivity to radiotherapy. Combining APMP with photothermal therapy (PTT) and RT is a promising glioblastoma treatment strategy, achieving tumor destruction via localized hyperthermia and overcoming radioresistance. This approach achieves precise tumor targeting, reducing side effects and enhancing therapeutic response in preclinical models. The novel core-shell design enables potent radiotherapy-specific radiosensitizers that drive immunogenic cell death, enhancing glioblastoma combination immunotherapy. This universal strategy heralds a new era in integrating radiotherapy sensitizers with immunotherapy.

Oxygen-delivery nanoparticles enhanced immunotherapy efficacy monitored by granzyme B PET imaging in malignant tumors

Limited treatment response and inadequate monitoring methods stand firmly before successful immunotherapy. Recruiting and activating immune cells in the hypoxic tumor microenvironment is the key to reversing immune suppression and improving immunotherapy efficacy. In this study, biomimetic oxygen-delivering nanoparticles (CmPF) are engineered for homologous targeting and hypoxia alleviation within the tumor environment. CmPF targets the tumor microenvironment and delivers oxygen to reduce hypoxia, thereby promoting immune cell activity at the tumor site. In addition, granzyme B-targeted positron emission tomography (PET) imaging is employed to monitor immune cell activity changes in response to immunotherapy efficacy in vivo. The combination of CmPF with carboplatin and PD-1 inhibitors significantly suppresses tumor growth by 2.4-fold, exhibiting the potential of CmPF to enhance the efficacy of immunotherapy. Immunohistochemistry further confirms increased expression of key immune markers, highlighting the reprogramming of the tumor microenvironment. This study demonstrates that hypoxia alleviation enhances tumor immunotherapy efficacy and introduces a non-invasive PET imaging method for dynamic, real-time assessment of therapeutic response.

Harnessing nanoparticles for reshaping tumor immune microenvironment of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers, characterized by high morbidity and mortality rates. Recently, immunotherapy has emerged as a crucial treatment modality for HCC, following surgery, locoregional therapies, and targeted therapies. This approach harnesses the body's immune system to target and eliminate cancer cells, potentially resulting in durable antitumor responses. However, acquired resistance and the tumor immunosuppressive microenvironment (TIME) significantly hinder its clinical application. Recently, advancements in nanotechnology, coupled with a deeper understanding of cancer biology and nano-biological interactions, have led to the development of various nanoparticles aimed at enhancing therapeutic efficacy through specific targeting of tumor tissues. These nanoparticles increase the accumulation of immunotherapeutic drugs within the tumor microenvironment, thereby transforming the TIME. In this review, we provide a concise overview of the fundamental principles governing the TIME landscape in HCC and discuss the rationale for and applications of nanoparticles in this context. Additionally, we highlight existing challenges and potential opportunities for the clinical translation of cancer nanomedicines.

Advances in tumor stroma-based targeted delivery

The tumor stroma plays a crucial role in tumor progression, and the interactions between the extracellular matrix, tumor cells, and stromal cells collectively influence tumor progression and the efficacy of therapeutic agents. Currently, utilizing components of the tumor stroma for drug delivery is a noteworthy strategy. A number of targeted drug delivery systems designed based on tumor stromal components are entering clinical trials. Therefore, this paper provides a thorough examination of the function of tumor stroma in the advancement of targeted drug delivery systems. One approach is to use tumor stromal components for targeted drug delivery, which includes certain stromal components possessing inherent targeting capabilities like HA, laminin, along with targeting stromal cells homologously. Another method entails directly focusing on tumor stromal components to reshape the tumor stroma and facilitate drug delivery. These drug delivery systems exhibit great potential in more effective cancer therapy strategies, such as precise targeting, enhanced penetration, improved safety profile, and biocompatibility. Ultimately, the deployment of these drug delivery systems can deepen our comprehension of tumor stroma and the advanced development of corresponding drug delivery systems.

Biopolymer-based tumor microenvironment-responsive nanomedicine for targeted cancer therapy

Nanomedicine has opened up new avenues for cancer treatment by enhancing drug solubility, permeability and targeted delivery to cancer cells. Despite its numerous advantages over conventional therapies, nanomedicine may exhibit off-target drug distribution, harming nontarget regions. The increased permeation and retention effect of nanomedicine in tumor sites also has its limitations, as abnormal tumor vasculature, dense stroma structure and altered tumor microenvironment (TME) may result in limited intratumor distribution and therapeutic failure. However, TME-responsive nanomedicine has exhibited immense potential for efficient, safe and precise delivery of therapeutics utilizing stimuli specific to the TME. This review discusses the mechanistic aspects of various TME-responsive biopolymers and their application in developing various types of TME-responsive nanomedicine.

Chondroitin sulfate-modified antiangiogenic peptide conjugate induces cell apoptosis via the mitochondria-mediated pathway to perform antitumor activity

Tumor growth and metastasis heavily rely on angiogenesis, crucial for solid tumor development. Inhibiting angiogenesis associated with tumors emerges as a potent therapeutic approach. Our previous work synthesized the chondroitin sulfate-modified antiangiogenic peptide CS-ES2-AF (CS-EA), which exhibited better antiangiogenic activity, longer half-life, and more robust targeting. In this work, we further evaluated the stability in vitro, cellular uptake mechanism, cell apoptosis mechanism, antitumor activity in vivo, and safety of CS-EA. The stability of CS-EA was consistently superior to that of EA at different temperatures and in different pH ranges. Furthermore, CS-EA mainly entered EAhy926 cells through the clathrin-mediated endocytosis pathway. CS-EA inhibited endothelial cell proliferation, and induced cell apoptosis through downregulating the Bcl-2, reducing mitochondria membrane potential, upregulating cytochrome c, Caspase 3, and reactive oxygen species levels. CS-EA showed better antitumor activity in the B16 xenografted tumor model, with a tumor inhibition rate 1.92 times higher than EA. Simultaneously, it was observed that CS-EA did not cause any harmful effects on the vital organs of the mice. These findings indicate that CS-EA holds significant promise for the treatment of tumors.

Study of alloferon, a novel immunomodulatory antimicrobial peptide (AMP), and its analogues

Antimicrobial peptides (AMPs) are widely distributed throughout the biosphere and represent a class of conserved peptide molecules with intrinsic antimicrobial properties. Their broad-spectrum antimicrobial activity and low risk to induce resistance have led to increased interest in AMPs as potential alternatives to traditional antibiotics. Among the AMPs, alloferon has been addressed due to its immunomodulatory properties that augment both innate and adaptive immune responses against various pathogens. Alloferon and its analogues have demonstrated pharmaceutical potential through their ability to enhance Natural Killer (NK) cell cytotoxicity and stimulate interferon (IFN) synthesis in both mouse and human models. Additionally, they have shown promise in augmenting antiviral and antitumor activities in mice. In this article, we provide a comprehensive review of the biological effects of alloferon and its analogues, incorporating our own research findings as well. These insights may contribute to a deeper understanding of the therapeutic potential of these novel AMPs.

Polymer-based nanosystems and their applications in bone anticancer therapy

The mortality rate of bone cancer has witnessed a substantial reduction in recent years, all thanks to the advent of advanced cancer treatment modalities such as surgical intervention, radiation, and chemotherapy. Nevertheless, these popular modalities come with a set of clinical challenges, including non-specificity, side effects, and drug intolerance. In recent years, polymer-based nanosystems have emerged as a promising solution in bone anti-cancer therapy by virtue of their unique physical and chemical properties. These nanosystems can be tailored for use in different drug release mechanisms for therapeutic implementations. This review delves into the efficacy of these therapy applications in bone cancer (with a focus on one of the most common types of cancers, Osteosarcoma) treatment and their correlation with the properties of polymer-based nanosystems, in addition to their interaction with the tumor microenvironment and the biological milieu.

A multi-bioresponsive self-assembled nano drug delivery system based on hyaluronic acid and geraniol against liver cancer

Herein, a multi-bioresponsive self-assembled nano-drug delivery system (HSSG) was constructed by conjugating the anticancer drug Geraniol (GER) to hyaluronic acid (HA) via a disulfide bond. The HSSG NPs displayed a uniform spherical shape with an average diameter of ∼110 nm, maintained high stability, and realized controlled drug release in the tumor microenvironment (pH/glutathione/hyaluronidase). Results of fluorescence microscopy and flow cytometry verified that HSSG NPs were selectively uptaken by human hepatocellular carcinoma cell lines HepG2 and Huh7 via CD44 receptor-mediated internalization. Studies on H22 tumor-bearing mice demonstrate that HSSG NPs could effectively accumulate at the tumor site for a long period. In vitro and in vivo studies show that HSSG NPs significantly promoted the death of cancer cells while reducing the toxicity as compared to GER. Therefore, the HSSG NPs have great potential in the treatment of tumors.

Nanotechnology-based photo-immunotherapy: a new hope for inhibition of melanoma growth and metastasis

Melanoma is the most aggressive form of skin cancer and there is a need for the development of effective anti-melanoma therapies as it shows high metastatic ability and low response rate. In addition, it has been identified that traditional phototherapy could trigger immunogenic cell death (ICD) to activate antitumor immune response, which could not only effectively arrest primary tumor growth, but also exhibit superior effects in terms of anti-metastasis, anti-recurrence for metastatic melanoma treatment However, the limited tumor accumulation of photosensitizers/photothermal agents and immunosuppressive tumor microenvironment severely weaken the immune effects. The application of nanotechnology facilitates a higher accumulation of photosensitizers/photothermal agents at the tumor site, which can thus improve the antitumor effects of photo-immunotherapy (PIT). In this review, we summarize the basic principles of nanotechnology-based PIT and highlight novel nanotechnologies that are expected to enhance the antitumor immune response for improved therapeutic efficacy.

Stimuli-responsive heparin-drug conjugates co-assembled into stable nanomedicines for cancer therapy

The combination of chemotherapy and photodynamic therapy (PDT) has the potential to complement single-drug therapies, but chemotherapeutic agents and photosensitizers often have compromised therapeutic efficacies and strong toxic effects. In this study, we exploited nanotechnology to address this challenge by utilizing heparin as a carrier for co-delivery of chemotherapeutic drugs and photosensitizers for synergistic cancer therapy. Specifically, heparin-paclitaxel (HP-PTX) and heparin-pyropheophorbide-a (HP-Ppa) were synthesized by attaching paclitaxel (PTX), a small molecular chemotherapeutic drug, through a reactive oxygen species (ROS)-responsive linker and Ppa, a photosensitizer, to heparin, respectively. Two conjugates co-assembled into a nanomedicine, HP-PP nanoparticles (NPs), for controllable co-delivery of Ppa and PTX into tumor cells. HP-PP NPs significantly enhanced the in vitro stability of HP-Ppa and the photostability of Ppa, and the synergistic actions of chemotherapy and PDT were confirmed from both in vitro and in vivo antitumor studies. Notably, HP-PP NPs enhanced tumor accumulation of Ppa up to 11-fold and the treatment of 4T1 tumor-bearing mice with HP-PP NPs resulted in a tumor growth inhibition of 98.1% without systemic toxicity. The strategy of co-assembly of heparin conjugates may offer great potential in enhancing the efficacy of combination therapy. STATEMENT OF SIGNIFICANCE: : We proposed a nano-delivery system, HP-PP NPs, which was constructed by co-assembly of heparin-paclitaxel (HP-PTX) and heparin-pyropheophorbide-a (HP-Ppa), to co-deliver PTX and Ppa for synergistic cancer therapy. HP-PP NPs enhanced the photostability and the in vitro stability of Ppa and HP-Ppa, and induced greater cytotoxicity than HP-PTX NPs or HP-Ppa NPs. This co-delivery system displays enhanced tumor accumulation and has a remarkable synergistic antitumor effect with a tumor growth inhibition of 98.1%.

Paclitaxel-Loaded Lipid-Coated Magnetic Nanoparticles for Dual Chemo-Magnetic Hyperthermia Therapy of Melanoma

Melanoma is the most aggressive and metastasis-prone form of skin cancer. Conventional therapies include chemotherapeutic agents, either as small molecules or carried by FDA-approved nanostructures. However, systemic toxicity and side effects still remain as major drawbacks. With the advancement of nanomedicine, new delivery strategies emerge at a regular pace, aiming to overcome these challenges. Stimulus-responsive drug delivery systems might considerably reduce systemic toxicity and side-effects by limiting drug release to the affected area. Herein, we report the development of paclitaxel-loaded lipid-coated manganese ferrite magnetic nanoparticles (PTX-LMNP) as magnetosomes synthetic analogs, envisaging the combined chemo-magnetic hyperthermia treatment of melanoma. PTX-LMNP physicochemical properties were verified, including their shape, size, crystallinity, FTIR spectrum, magnetization profile, and temperature profile under magnetic hyperthermia (MHT). Their diffusion in porcine ear skin (a model for human skin) was investigated after intradermal administration via fluorescence microscopy. Cumulative PTX release kinetics under different temperatures, either preceded or not by MHT, were assessed. Intrinsic cytotoxicity against B16F10 cells was determined via neutral red uptake assay after 48 h of incubation (long-term assay), as well as B16F10 cells viability after 1 h of incubation (short-term assay), followed by MHT. PTX-LMNP-mediated MHT triggers PTX release, allowing its thermal-modulated local delivery to diseased sites, within short timeframes. Moreover, half-maximal PTX inhibitory concentration (IC50) could be significantly reduced relatively to free PTX (142,500×) and Taxol® (340×). Therefore, the dual chemo-MHT therapy mediated by intratumorally injected PTX-LMNP stands out as a promising alternative to efficiently deliver PTX to melanoma cells, consequently reducing systemic side effects commonly associated with conventional chemotherapies.

Alloferon-1 ameliorates acute inflammatory responses in λ-carrageenan-induced paw edema in mice

Alloferon-1 have been proposed as an effective peptide to enhance antitumoral immunity, antiviral defense and anti-inflammatory activity. This work aimed to assess anti-inflammatory effects of alloferon-1 against acute inflammation and histopathological deformations in λ-carrageenan-induced paw edema in mice. Systemic pretreatment with alloferon-1 (22.0 mg/kg) intraperitoneally injected mice showed a significant reduction in paw thickness and vascular permeability. Alloferon-1 prevented λ-carrageenan-evoked exudation and the neutrophil influx to the mouse pleura and the neutrophil migration into carrageenan-stimulated mouse air pouches based on the histopathological changes in the paw tissues. Administration of alloferon-1 also suppressed the expression of the inflammatory cytokines in the inflamed paw tissues such as tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein 1 (MCP1), interleukin-5 (IL-5), etc. detected by Luminex liquid chip. Collectively, the present study provides evidences for the marked anti-inflammatory effects of alloferon-1 which might represent new therapeutic options for the treatment of acute inflammatory diseases.

Enhancing the therapeutic efficacy of nanoparticles for cancer treatment using versatile targeted strategies

Poor targeting of therapeutics leading to severe adverse effects on normal tissues is considered one of the obstacles in cancer therapy. To help overcome this, nanoscale drug delivery systems have provided an alternative avenue for improving the therapeutic potential of various agents and bioactive molecules through the enhanced permeability and retention (EPR) effect. Nanosystems with cancer-targeted ligands can achieve effective delivery to the tumor cells utilizing cell surface-specific receptors, the tumor vasculature and antigens with high accuracy and affinity. Additionally, stimuli-responsive nanoplatforms have also been considered as a promising and effective targeting strategy against tumors, as these nanoplatforms maintain their stealth feature under normal conditions, but upon homing in on cancerous lesions or their microenvironment, are responsive and release their cargoes. In this review, we comprehensively summarize the field of active targeting drug delivery systems and a number of stimuli-responsive release studies in the context of emerging nanoplatform development, and also discuss how this knowledge can contribute to further improvements in clinical practice.

B16F10 Cell Membrane-Based Nanovesicles for Melanoma Therapy Are Superior to Hyaluronic Acid-Modified Nanocarriers

Some cancer cell membrane (CCM)-derived nanovesicles show strong homing effects and are used for targeted cancer therapy. By co-constructing the B16F10 cell membrane with a PEGylated phospholipid membrane, a new nanocarrier with a composite nanocrown structure was developed, which can evade immune recognition and actively target homologous melanoma. The nanocrowns have an encapsulation efficiency of more than 90% for paclitaxel and showed no significant difference (p > 0.05) from the PEGylated phospholipid membrane vesicles. Compared with the hyaluronic acid-modified PEGylated phospholipid membrane vesicles, the biomimetic nanocrowns enhanced the escape of nanovesicles from reticuloendothelial cells in vitro and extended the circulation time in vivo; moreover, the nanocrowns showed superior melanoma-targeted drug delivery capability and improved anticancer effects of paclitaxel as demonstrated by the inhibition of B16F10 cell proliferation and induction of apoptosis by interfering with microtubule formation. In contrast, the modification of hyaluronic acid did not increase the targeting capacity or antitumor effects of the nanocrowns, confirming that the superior targeting capacity was mediated by the exposed homologous CCMs rather than by hyaluronic acid. Our results demonstrate the potential of using biomimetic nanocrowns for active melanoma-targeted therapy.

Quadruple-responsive nanoparticle-mediated targeted combination chemotherapy for metastatic breast cancer

The synergism of combination chemotherapy can only be achieved under specific drug ratios. Herein, hyaluronic acid (HA)-functionalized regenerated silk fibroin-based nanoparticles (NPs) were used to concurrently deliver curcumin (CUR) and 5-fluorouracil (5-FU) at various weight ratios (3.3 : 1, 1.6 : 1, 1.1 : 1, 1 : 1, and 1 : 1.2) to breast tumor cells. The generated HA-CUR/5-FU-NPs were found to have desirable particle sizes (around 200 nm), narrow size distributions, and negative zeta potentials (about -26.0 mV). Interestingly, these NPs showed accelerated drug release rates when they were exposed to buffers that mimicked the multi-hallmarks in the tumor microenvironment (pH/hydrogen peroxide/glutathione/hyaluronidase). The surface functionalization of NPs with HA endowed them with in vitro and in vivo breast tumor-targeting properties. Furthermore, we found that the co-loading of CUR and 5-FU in HA-functionalized NPs exhibited obvious synergistic anti-cancer, pro-apoptotic, and anti-migration effects, and the strongest synergism was found at the CUR/5-FU weight ratio of 1 : 1.2. Most importantly, mice experiments revealed that HA-CUR/5-FU-NPs (1 : 1.2) showed a superior anti-cancer activity against metastatic breast cancer compared to the single drug-loaded NPs and non-functionalized CUR/5-FU-NPs (1 : 1.2). Collectively, these results demonstrate that HA-CUR/5-FU-NPs (1 : 1.2) can be exploited as a robust nanococktail for the treatment of breast cancer and its lung metastasis.

Advances of smart nano-drug delivery systems in osteosarcoma treatment

Nanotechnology has recently become popular due to its potential for biomedical applications, especially for cancer treatment. Nanotechnology, featuring responsiveness to stimuli and stable drug release, has been widely used for the delivery of chemotherapeutic drugs, which are commonly used in the treatment of osteosarcoma. Smart stimuli-responsive nanotechnology is expected to improve the treatment of osteosarcoma. Herein, we focus on the latest research on nanomaterials in treating osteosarcoma that respond to internal and external stimuli. We also discuss nanocarriers with targeting ligands and the use of smart nanotechnology to partially reverse the multidrug resistance of osteosarcoma.

Inhibition of growth and lung metastasis of breast cancer by tumor-homing triple-bioresponsive nanotherapeutics

Lung metastasis of breast cancer is a leading cause of cancer-related death in women. Herein, we attempted to simultaneously inhibit the growth and lung metastasis of breast cancer by delivering quercetin (QU) using LyP-1-functionalized regenerated silk fibroin-based nanoparticles (NPs). The generated LyP-1-QU-NPs had a desirable diameter (203.2 nm) and a negatively charged surface (-12.7 mV). Interestingly, these NPs exhibited intrinsic responsibilities when triggered by various stimulating factors in the tumor microenvironment (acidic pH, reactive oxygen species, and glutathione). In vitro experiments revealed that the introduction of LyP-1 to the NP surface could significantly increase their cellular uptake efficiencies by 4 T1 cells, and facilitate their accumulation in mitochondria. Moreover, LyP-1-QU-NPs showed the strongest mitochondrial damage effect among all the treatment groups. We also found that LyP-1-QU-NPs not only exhibited excellent pro-apoptotic activities but also presented strong inhibitory effects on cell mobility (migration and invasion) through anti-glycolysis and pro-autophagy. Mice experiments confirmed that LyP-1-QU-NPs could efficiently inhibit the in situ growth of breast tumors and further restrict their lung metastasis. Collectively, our results demonstrate that LyP-1-QU-NPs, which integrates the functions of tumor cell targeting, mitochondria targeting, bioresponsive drug release, pro-apoptosis, and anti-mobility, can be developed as a promising nanotherapeutic for the effective treatment of breast cancer and its lung metastasis.

Precise design strategies of nanomedicine for improving cancer therapeutic efficacy using subcellular targeting

Therapeutic efficacy against cancer relies heavily on the ability of the therapeutic agents to reach their final targets. The optimal targets of most cancer therapeutic agents are usually biological macromolecules at the subcellular level, which play a key role in carcinogenesis. Therefore, to improve the therapeutic efficiency of drugs, researchers need to focus on delivering not only the therapeutic agents to the target tissues and cells but also the drugs to the relevant subcellular structures. In this review, we discuss the most recent construction strategies and release patterns of various cancer cell subcellular-targeting nanoformulations, aiming at providing guidance in the overall design of precise nanomedicine. Additionally, future challenges and potential perspectives are illustrated in the hope of enhancing anticancer efficacy and accelerating the translational progress of precise nanomedicine.

CCR2-targeted micelles for anti-cancer peptide delivery and immune stimulation

Signaling between the CC chemokine receptor 2 (CCR2) with its ligand, monocyte chemoattractant protein-1 (MCP-1) promotes cancer progression by directly stimulating tumor cell proliferation and downregulating the expression of apoptotic proteins. Additionally, the MCP-1/CCR2 signaling axis drives the migration of circulating monocytes into the tumor microenvironment, where they mature into tumor-associated macrophages (TAMs) that promote disease progression through induction of angiogenesis, tissue remodeling, and suppression of the cytotoxic T lymphocyte (CTL) response. In order to simultaneously disrupt MCP-1/CCR2 signaling and target CCR2-expressing cancer cells for drug delivery, KLAK-MCP-1 micelles consisting of a CCR2-targeting peptide sequence (MCP-1 peptide) and the apoptotic KLAKLAK peptide were synthesized. In vitro, KLAK-MCP-1 micelles were observed to bind and induce cytotoxicity to cancer cells through interaction with CCR2. In vivo, KLAK-MCP-1 micelles inhibited tumor growth (34 ± 11%) in a subcutaneous B16F10 murine melanoma model despite minimal tumor accumulation upon intravenous injection. Tumors treated with KLAK-MCP1 demonstrated reduced intratumor CCR2 expression and altered infiltration of TAMs and CTLs as evidenced by immunohistochemical and flow cytometric analysis. These studies highlight the potential application of CCR2-targeted nanotherapeutic micelles in cancer treatment.