Multiple Treatment of Triple-Negative Breast Cancer Through Gambogic Acid-Loaded Mesoporous Polydopamine.

Triple-negative breast cancer (TNBC) is a highly heterogeneous subtype of breast cancer, characterized by aggressiveness and high recurrence rate. As monotherapy provides limited benefit to TNBC patients, combination therapy emerges as a promising treatment approach. Gambogic acid (GA) is an exceedingly promising anticancer agent. Nonetheless, its application potential is hampered by low drug loading efficiency and associated toxic side effects. To overcome these limitations, using mesoporous polydopamine (MPDA) endowed with photothermal conversion capabilities is considered as a delivery vehicle for GA. Meanwhile, GA can inhibit the activity of heat shock protein 90 (HSP90) to enhance the photothermal effect. Herein, GA-loaded MPDA nanoparticles (GA@MPDA NPs) are developed with a high drug loading rate of 75.96% and remarkable photothermal conversion performance. GA@MPDA NPs combined with photothermal treatment (PTT) significantly inhibit the tumor growth, and effectively trigger the immunogenic cell death (ICD), which thereby increase the number of activated effector T cells (CD8+ T cells and CD4+ T cells) in the tumor, and hoist the level of immune-inflammatory cytokines (IFN-γ, IL-6, and TNF-α). The above results suggest that the combination of GA@MPDA NPs with PTT expected to activate the antitumor immune response, thus potentially enhancing the clinical therapeutic effect on TNBC.

The development and progress of nanomedicine for esophageal cancer diagnosis and treatment.

Esophageal cancer (EC) is a common gastrointestinal malignancy with poor prognosis and high mortality. Although combined therapeutic strategies have been developed, the 5-year survival rate of patients with EC remains relatively poor. Conventional anti-cancer drug delivery techniques have some shortcomings, such as nontargeted delivery and nonspecific toxicity. Nanoparticles (NPs) provide a promising platform for delivering drugs in various therapeutic modalities for EC, which possess several remarkable advantages in cancer therapy, such as reduced side effects, prolonged circulation time, and preferential accumulation at the tumor site. In this review, we summarized various types of NPs applied in the treatment of EC, including polymers, micelles, liposomes, inorganic NPs and organic NPs. Meanwhile, we discussed the efficacy and safety of newly designed nanomedicine in various treatments of EC, including chemotherapy, radiotherapy, gene therapy, photodynamic therapy (PDT), photothermal therapy (PTT), and their synergetic therapy. In addition, nanomedicine applied in tumor imaging and diagnoses were also reviewed. Current studies have suggested the potential advantages of nanoformulations over conventional formulations. More researches to promote clinical translation of nanomedicine for EC are anticipated in the future.

Rosmarinic Acid-Crosslinked Supramolecular Nanoassembly with Self-Regulated Photodynamic and Anti-Metastasis Properties for Synergistic Photoimmunotherapy.

A primary concern about photodynamic therapy (PDT) is its inability to regulate the generation levels of reactive oxidative species (ROS) based on the complex microenvironment, resulting in the impairment toward normal tissues and immunosuppression. Besides, tumor metastasis also compromises PDT's efficacy and drives mortality. However, it is very challenging to achieve such two goals within one nanosystem. Here, the nanoassembly (CPR) with self-regulated photodynamic and antimetastasis properties comprises three parts: chlorin e6-conjugated ß-cyclodextrin (CD-Ce6) acts as the main PDT agent and ferrocene (Fc)-terminated phenylboronic acid-containing conjugates entering into the cavity of CD-Ce6, as well as rosmarinic acid (RA)-boronic acid crosslinked shell. Compared with non-crosslinked counterpart, CPR displays better stability and enhanced tumor accumulation. Under laser irradiation, CPR generates plenty of ROS to damage tumor cells and induce immunogenic cell death. Mildly acidic TME partly cleaves the crosslinkers to dissociate antioxidant RAs from micelles, which together with Fc in CPR scavenge PDT-induced ROS in the TME. By contrast, under acidic lysosomal conditions, Fc catalyzes abundant H2 O2 in tumor cells to produce highly cytotoxic •OH, while RA continuously reduces ferroptosis-generated Fc+ into Fc, both to augment the PDT efficacy in tumor cells. CPR also remarkably hinders the epithelial-mesenchymal transition to prevent the lung metastasis.

Hsp70-Targeting and Size-Tunable Nanoparticles Combine with PD-1 Checkpoint Blockade to Treat Glioma.

Invasive glioma usually disrupts the integrity of the blood-brain barrier (BBB), making the delivery of nanodrugs across the BBB possible, but sufficient targeting ability is still avidly needed to improve drug accumulation in glioma. Membrane-bound heat shock protein 70 (Hsp70) is expressed on the membrane of glioma cells rather than adjacent normal cells, therefore it can serve as a specific glioma target. Meanwhile, prolonging the retention in tumors is important for active-targeting nanoparticles to overcome receptor-binding barriers. Herein, the Hsp70-targeting and acid-triggered self-assembled gold nanoparticles (D-A-DA/TPP) are proposed to realize selective delivery of doxorubicin (DOX) to glioma. In the weakly acidic glioma matrix, D-A-DA/TPP formed aggregates to prolong retention, improve receptor-binding efficiency and facilitate acid-responsive DOX release. DOX accumulation in glioma induced immunogenic cell death (ICD) to promote antigen presentation. Meanwhile, combination with the PD-1 checkpoint blockade further activate T cells and provokes robust anti-tumor immunity. The results showed that D-A-DA/TPP can induce more glioma apoptosis. Furthermore, in vivo studies indicated D-A-DA/TPP plus PD-1 checkpoint blockade significantly improved median survival time. This study offeres a potential nanocarrier combining size-tunable strategy with active targeting ability to increase drug enrichment in glioma and synergizes with PD-1 checkpoint blockade to achieve chemo-immunotherapy.

In Situ Tumor Vaccine for Lymph Nodes Delivery and Cancer Therapy Based on Small Size Nanoadjuvant.

Tumor vaccine is a promising cancer treatment modality, however, the convenient antigens loading in vivo and efficient delivery of vaccines to lymph nodes (LNs) still remain a formidable challenge. Herein, an in situ nanovaccine strategy targeting LNs to induce powerful antitumor immune responses by converting the primary tumor into whole-cell antigens and then delivering these antigens and nanoadjuvants simultaneously to LNs is proposed. The in situ nanovaccine is based on a hydrogel system, which loaded with doxorubicin (DOX) and nanoadjuvant CpG-P-ss-M. The gel system exhibits ROS-responsive release of DOX and CpG-P-ss-M, generating abundant in situ storage of whole-cell tumor antigens. CpG-P-ss-M adsorbs tumor antigens through the positive surface charge and achieves charge reversal, forming small-sized and negatively charged tumor vaccines in situ, which are then primed to LNs. Eventually, the tumor vaccine promotes antigens uptake by dendritic cells (DCs), maturation of DCs, and proliferation of T cells. Moreover, the vaccine combined with anti-CTLA4 antibody and losartan inhibits tumor growth by 50%, significantly increasing the percentage of splenic cytotoxic T cells (CTLs), and generating tumor-specific immune responses. Overall, the treatment effectively inhibits primary tumor growth and induces tumor-specific immune response. This study provides a scalable strategy for in situ tumor vaccination.

Multifunctional Nanotheranostics for Dual-Modal Imaging-Guided Precision Therapy of Nasopharyngeal Carcinoma.

Currently, the low survival rate and poor prognosis of patients with nasopharyngeal carcinoma are ascribed to the lack of early and accurate diagnosis and resistance to radiotherapy. In parallel, the integration of imaging-guided diagnosis and precise treatment has gained much attention in the field of theranostic nanotechnology. However, constructing dual-modal imaging-guided nanotheranostics with desired imaging performance as well as great biocompatibility remains challenging. Therefore, we developed a simple but multifunctional nanotheranostic GdCPP for the early and accurate diagnosis and efficient treatment of nasopharyngeal carcinoma (NPC), which combined fluorescence imaging and magnetic resonance imaging (MRI) onto a single nanoplatform for imaging-guided subsequent photodynamic therapy (PDT). GdCPP had an appropriate particle size (81.93 ± 0.69 nm) and was highly stable, resulting in sufficient tumor accumulation, which along with massive reactive oxygen species (ROS) generation upon irradiation further significantly killed tumor cells. Moreover, GdCPP owned much stronger r1 relaxivity (9.396 mM-1 s-1) compared to clinically used Gd-DTPA (5.034 mM-1 s-1) and exhibited better T1WI MRI performance. Under dual-modal imaging-guided PDT, GdCPP achieved efficient therapeutic outcomes without causing any noticeable tissue damage. The results of in vitro and in vivo studies indicated that GdCPP may be a suitable candidate for dual-modal imaging-guided precision tumor therapy.

Hypoxia-cleavable and specific targeted nanomedicine delivers epigenetic drugs for enhanced treatment of breast cancer and bone metastasis.

Breast cancer bone metastasis has become a common cancer type that still lacks an effective treatment method. Although epigenetic drugs have demonstrated promise in cancer therapy, their nontargeted accumulation and drug resistance remain nonnegligible limiting factors. Herein, we first found that icaritin had a strong synergistic effect with an epigenetic drug (JQ1) in the suppression of breast cancer, which could help to relieve drug resistance to JQ1. To improve tumor-targeted efficacy, we developed a hypoxia-cleavable, RGD peptide-modified poly(D,L-lactide-co-glycolide) (PLGA) nanoparticle (termed ARNP) for the targeted delivery of JQ1 and icaritin. The decoration of long cleavable PEG chains can shield RGD peptides during blood circulation and reduce cellular uptake at nonspecific sites. ARNP actively targets breast cancer cells via an RGD-αvß3 integrin interaction after PEG chain cleavage by responding to hypoxic tumor microenvironment. In vitro and in vivo assays revealed that ARNP exhibited good biodistribution and effectively suppressed primary tumor and bone metastasis. Meanwhile, ARNP could alleviate bone erosion to a certain extent. Furthermore, ARNP significantly inhibited pulmonary metastasis secondary to bone metastasis. The present study suggests that ARNP has great promise in the treatment of breast cancer and bone metastasis due to its simple and practical potential.

pH-Triggered Size-Tunable Silver Nanoparticles: Targeted Aggregation for Effective Bacterial Infection Therapy.

The rapid spread of drug-resistant pathogens threatens human health. To address the current antibacterial dilemma, the development of antibiotic-free strategies using nanotechnology is imperative. In this study, silver nanoparticles (Ag-P&C NPs) with pH-sensitive charge reversal and self-aggregation capacities are successfully synthesized. In the acidic microenvironment of bacterial biofilms, protonation of the surface peptide enhances the affinity of Ag-P&C NPs for bacteria, which can make Ag-P&C NPs prone to target and penetrate into biofilms, and the self-aggregated capacity helps Ag-P&C NPs remain in biofilms for a long time to disrupt bacterial biofilm formation. In addition, biocompatible Ag-P&C NPs are utilized in three types of bacteria-infected animal models. They exhibit an excellent performance in killing bacteria, inhibiting plaque biofilms, and ameliorating inflammatory responses. In conclusion, this study offers new insights into antibiotic-free antibacterial strategies, and exhibits promising application prospects.

Intranasal Delivery of BACE1 siRNA and Rapamycin by Dual Targets Modified Nanoparticles for Alzheimer's Disease Therapy.

Alzheimer's disease (AD), as a progressive and irreversible brain disorder, remains the most universal neurodegenerative disease. No effective therapeutic methods are established yet due to the hindrance of the blood-brain barrier (BBB) and the complex pathological condition of AD.  Therefore, a multifunctional nanocarrier (Rapa@DAK/siRNA) for AD treatment is constructed to achieve small interfering RNA of ß-site precursor protein (APP) cleaving enzyme-1 (BACE1 siRNA) and rapamycin co-delivery into the brain, based on Aleuria aurantia lectin (AAL) and ß-amyploid (Aß)-binding peptides (KLVFF) modified PEGylated dendrigraft poly-l-lysines (DGLs) via intranasal administration. Nasal administration provides an effective way to deliver drugs directly into the brain through the nose-to-brain pathway. AAL, specifically binding to L-fucose located in the olfactory epithelium, endows Rapa@DAK/siRNA with high brain entry efficiency through intranasal administration. KLVFF peptide as an Aß targeting ligand and aggregation inhibitor enables nanoparticles to bind with Aß, inhibit Aß aggregation, and reduce toxicity. Meanwhile, the release of BACE1 siRNA and rapamycin is confirmed to reduce BACE1 expression, promote autophagy, and reduce Aß deposition. Rapa@DAK/siRNA is verified to improve the cognition of transgenic AD mice after intranasal administration. Collectively, the multifunctional nanocarrier provides an effective and potential intranasal avenue for combination therapy of AD.

Acid-Responsive Aggregated Gold Nanoparticles for Radiosensitization and Synergistic Chemoradiotherapy in the Treatment of Esophageal Cancer.

Radiotherapy and chemotherapy are limited by insufficient therapeutic efficacy of low-dose radiation and nonspecific drug biodistribution. Herein, an acid-responsive aggregated nanosystem (AuNPs-D-P-DA) loaded with doxorubicin (DOX) is designed for radiosensitization and synergistic chemoradiotherapy. In response to the acid microenvironment of esophageal cancer (EC), small-sized AuNPs-D-P-DA forms large-sized gold nanoparticle (AuNPs) aggregates in tumor tissues to hinder the backflow of AuNPs to the circulation, resulting in enhanced tumor accumulation and retention. Simultaneously, the AuNPs-based radiosensitization is significantly improved because of the high concentration and large size of intratumoral AuNPs, while DOX are delivered and released specifically into tumor cells triggered by the acid microenvironment for chemo-radio synergistic therapy. Acid-responsive AuNPs exacerbate radiation-induced DNA damage, cell apoptosis, cell cycle arrest, and low colony formation ability in vitro and enhance anti-tumor efficacy in vivo compared to un-responsive control. When combined with acid-responsive DOX, the therapeutic efficacy of the formulation is further improved by their synergistic effect. After the treatment of acid-responsive AuNPs plus radiotherapy, fatty acid metabolism is reprogrammed in xenograft models, which provides potential targets for further improvement of radiosensitization. In summary, the acid-responsive AuNPs-D-P-DA nanosystem leverages the radio- and chemotherapeutic synergies of AuNPs-sensitized X-ray irradiation and acid-responsive DOX in the treatment of EC.

A roadmap to pulmonary delivery strategies for the treatment of infectious lung diseases.

Pulmonary drug delivery is a highly attractive topic for the treatment of infectious lung diseases. Drug delivery via the pulmonary route offers unique advantages of no first-pass effect and high bioavailability, which provides an important means to deliver therapeutics directly to lung lesions. Starting from the structural characteristics of the lungs and the biological barriers for achieving efficient delivery, we aim to review literatures in the past decade regarding the pulmonary delivery strategies used to treat infectious lung diseases. Hopefully, this review article offers new insights into the future development of therapeutic strategies against pulmonary infectious diseases from a delivery point of view.

Nanovaccine-Based Strategies to Overcome Challenges in the Whole Vaccination Cascade for Tumor Immunotherapy.

Nanovaccine-based immunotherapy (NBI) has received greater attention recently for its potential to prime tumor-specific immunity and establish a long-term immune memory that prevents tumor recurrence. Despite encouraging results in the recent studies, there are still numerous challenges to be tackled for eliciting potent antitumor immunity using NBI strategies. Based on the principles that govern immune response, here it is proposed that these challenges need to be addressed at the five critical cascading events: Loading tumor-specific antigens by nanoscale drug delivery systems (L); Draining tumor antigens to lymph nodes (D); Internalization by dendritic cells (DCs) (I); Maturation of DCs by costimulatory signaling (M); and Presenting tumor-peptide-major histocompatibility complexes to T cells (P) (LDIMP cascade in short). This review provides a detailed and objective overview of emerging NBI strategies to improve the efficacy of nanovaccines in each step of the LDIMP cascade. It is concluded that the balance between each step must be optimized by delicate designing and modification of nanovaccines and by combining with complementary approaches to provide a synergistic immunity in the fight against cancer.

Unraveling the Effect of Breast Cancer Patients' Plasma on the Targeting Ability of Folic Acid-Modified Chitosan Nanoparticles.

The formation of protein corona (PC) around nanoparticles (NPs) has been reported inside biological conditions. This effect can alter delivery capacity toward the targeted tissues. Here, we synthesized folic acid-modified chitosan NPs (FA-CS NPs) using different concentrations of folic acid (5, 10, and 20%). FA-CS NPs were exposed to plasmas of breast cancer patients and healthy donors to evaluate the possibility of PC formation. We also monitored uptake efficiency in in vitro conditions after incubation with human breast cancer cell line MDA-MB-231 and monocyte/macrophage-like Raw264.7 cells. Data showed that the formation of PC around FA-CS NPs can change physicochemical properties coincided with the rise in NP size and negative surface charge. SDS-PAGE electrophoresis revealed differences in the type and content rate of plasma proteins attached to NP surface in a personalized manner. Based on MTT data, the formation of PC around NPs did not exert cytotoxic effects on MDA-MB-231 cells while this phenomenon reduced uptake rate. Fluorescence imaging and flow cytometry analyses revealed reduced cellular internalization rate in NPs exposed to patients' plasma compared to the control group. In contrast to breast MDA-MB-231 cells, Raw264.7 cells efficiently adsorbed the bare and PC-coated NPs from both sources, indicating the involvement of ligand-receptor-dependent and independent cellular engulfment. These data showed that the PC formed on the FA-CS NPs is entirely different in breast cancer patients and healthy counterparts. PC derived from patients' plasma almost abolishes the targeting efficiency of FA-CS NPs even in different mechanisms, while this behavior was not shown in the control group. Surprisingly, Raw264.7 cells strongly adsorbed the PC-coated NPs, especially when these particles were in the presence of patients' sera. It is strongly suggested that the formation of PC around can affect delivering capacity of FA-CS NPs to cancer cells. It seems that the PC-coated FA-CS NPs can be used as an efficient delivery strategy for the transfer of specific biomolecules in immune system disorders.

Enhanced Cancer-targeted Drug Delivery Using Precoated Nanoparticles.

While protein coronas (PCs) are an important barrier in the clinical application of nanomedicines, the specific effects of PCs on nanoparticles (NPs) in vivo are unclear. Herein, we demonstrated that PCs from clinical sources greatly influenced the active targeting capacities of transferrin-modified NPs (Tf-NPs). Compared to PCs from healthy volunteers, PCs from the plasma of patients with nonsmall cell lung cancer (NSCLC) decreased the A549 uptake of Tf-NPs to a greater degree. The PC proteome revealed that this difference may be mediated by certain proteins in plasma. To attenuate the negative influence of PCs from patients, precoating Tf-NPs with PCs derived from healthy mice significantly enhanced active targeting capacities. Paclitaxel-loaded Tf-NPs with PCs derived from healthy mice showed the strongest antitumor effects in mice with NSCLC. This work illustrates the influence of PCs of ligand-modified NPs in clinical practice and proposes the use of corona-enabled active targeting for precision nanomedicine.

Aggregable Nanoparticles-Enabled Chemotherapy and Autophagy Inhibition Combined with Anti-PD-L1 Antibody for Improved Glioma Treatment.

Glioma treatment using targeted chemotherapy is still far from satisfactory due to not only the limited accumulation but also the multiple survival mechanisms of glioma cells, including up-regulation of both autophagy and programmed cell death ligand 1 (PD-L1) expression. Herein, we proposed a combined therapeutic regimen based on functional gold nanoparticles (AuNPs)-enabled chemotherapy, autophagy inhibition, and blockade of PD-L1 immune checkpoint. Specifically, the legumain-responsive AuNPs (D&H-A-A&C) could passively target the glioma site and form in situ aggregates in response to legumain, leading to enhanced accumulation of doxorubicin (DOX) and hydroxychloroquine (HCQ) at the glioma site. HCQ could inhibit the DOX-induced cytoprotective autophagy and thus resensitize glioma cells to DOX. Parallelly, inhibiting autophagy could also inhibit the formation of autophagy-related vasculogenic mimicry (VM) by glioma stem cells. In vivo studies demonstrated that D&H-A-A&C possessed promising antiglioma effect. Moreover, cotreatment with anti-PD-L1 antibody was able to neutralize immunosuppressed glioma microenvironment and thus unleash antiglioma immune response. In vivo studies showed D&H-A-A&C plus anti-PD-L1 antibody could further enhance antiglioma effect and efficiently prevent recurrence. The effectiveness of this strategy presents a potential avenue to develop a more effective and more personalized combination therapeutic regimen for glioma patients.

Losartan loaded liposomes improve the antitumor efficacy of liposomal paclitaxel modified with pH sensitive peptides by inhibition of collagen in breast cancer.

The dense collagen network in tumors restricts the penetration of drugs into tumors. Free losartan could inhibit collagen, but it would cause hypotension at the dosage of 10 mg/kg/d. In this study, losartan was encapsulated in liposomes (LST-Lip) and the collagen inhibition ability of LST-Lip was investigated. Our results showed the blood pressure was not affected by LST-Lip at the dosage of 2.5 mg/kg every other day. The amount of Evans Blue in tumor in LST-Lip group was 1.98 times of that in control group. Confocal laser scanning microscopy images showed that prior injection of LST-Lip could inhibit collagen and further improve the tumorous accumulation of liposomes modified with TH peptides (AGYLLGHINLHHLAHL(Aib)HHIL-NH2) (TH-Lip) in 4T1 tumors. Compared with control group, the tumor inhibition rate of combined strategy of LST-Lip and paclitaxel loaded TH-Lip (PTX-TH-Lip) was 41.73%, while that of group only treated with PTX-TH-Lip was 14.94%. Masson's trichrome staining confirmed that collagen was inhibited in LST-Lip group. Thus, the administration of LST-Lip in advance could inhibit the collagen in tumors effectively and did not affect the blood pressure, then PTX-TH-Lip injected subsequently could exert enhanced antitumor efficacy. In conclusion, this combined strategy might be promising for breast cancer therapy.

Normalizing Tumor Vessels To Increase the Enzyme-Induced Retention and Targeting of Gold Nanoparticle for Breast Cancer Imaging and Treatment.

Abnormal tumor vessels impede the transport and distribution of chemotherapeutics, resulting in low drug concentration at tumor sites and compromised drug efficacy. Normalizing tumor vessels can modulate tumor vascular permeability, alleviate tumor hypoxia, increase blood perfusion, attenuate interstitial fluid pressure, and improve drug delivery. Herein, a novel strategy combining cediranib, a tumor vessel normalizing agent, with an enzyme responsive size-changeable gold nanoparticle (AuNPs-A&C) was developed. In vivo photoacoustic and fluorescence imaging showed that oral pretreatment with 6 mg/kg/day of cediranib for two consecutive days significantly enhanced the retention of AuNPs-A&C in 4T1 tumor. In vivo photoacoustic imaging for hemoglobin (Hb) and oxyhemoglobin (HbO2), Evans blue assay, and immunofluorescence assay showed that cediranib pretreatment markedly increased tumor vascular permeability and tumor oxygenation, while distinctly decreased the tumor microvessel density, demonstrating normalized tumor vessels and favorably altered microenvironment. Additionally, the combination strategy considerably elevated the tumor targeting capacity of different nanoparticle formulations (AuNPs-PEG, AuNPs-A&C), while coadministration of cediranib and AuNPs-A&C achieved prevailing tumor targeting and antitumor efficacy in 4T1 tumor bearing mouse model. In conclusion, we report a novel combined administration strategy to further improve tumor diagnosis and treatment.

Inducing Optimal Antitumor Immune Response through Coadministering iRGD with Pirarubicin Loaded Nanostructured Lipid Carriers for Breast Cancer Therapy.

Chemotherapeutic agents trigger antitumor immune response through inducing immunogenic tumor cell death. However, severe toxicity to immune system and insufficient immunogenic cell death hinder chemotherapy from arousing efficient antitumor immunity in vivo. In this study, the cytotoxic drug, pirarubicin (THP), was entrapped into nanostructured lipid carriers (NLC); THP-NLC significantly reduced the toxicity of THP to immune system and improved immune status of breast cancer bearing mice. When THP-NLC was coinjected with iRGD (a tumor-penetrating peptide), drug accumulation in tumors was greatly elevated, which led to significant control of tumor growth and increase of immunogenic tumor cell death. Subsequently, the cytotoxic T lymphocytes (CD3+ and CD8+ cells) infiltration and cytokine (IFN-γ and INF-α) secretion in tumors were heavily increased. The efficient T-cell dependent control of tumors in the late stage and the lower side effects contributed to the longest whole survival of THP-NLC + iRGD treated mice. Therefore, the coadministration of THP-NLC with iRGD resulted in increased tumor cell direct-killing death and enhanced antitumor immune response. Our results illustrated that THP could serve as an immunogenic cell death inducer and the proposed drug delivery strategy might impact cancer immunotherapy by arousing increased immunogenic tumor cell death.

Nanoparticles for modulating tumor microenvironment to improve drug delivery and tumor therapy.

Tumor microenvironment (TME) plays a critical role in tumorigenesis, tumor invasion and metastasis. TME is composed of stroma, endothelial cells, pericytes, fibroblasts, smooth muscle cells, and immune cells, which is characterized by hypoxia, acidosis, and high interstitial fluid pressure. Due to the important role of TME, we firstly reviewed the composition of TME and discussed the impact of TME on tumor progression, drug and nanoparticle delivery. Next, we reviewed current strategies developed to modulate TME, including modulating tumor vasculature permeability, tumor associated macrophage phenotypes, tumor associated fibroblasts, tumor stroma components, tumor hypoxia, and multiple interventions simultaneously. Also, potential problems and future directions of TME modulation strategy have been discussed.

Matrix metalloproteases-responsive nanomaterials for tumor targeting diagnosis and treatment.

Tumour poses tremendous challenges to mankind. In various tumours, matrix metalloproteases (MMPs) are ubiquitously over expressed and participate throughout the process of tumour development. MMPs are commonly used as internal stimuli, and MMPs-responsive nanomaterials are classified into three categories according to the drug delivery process: administration and distribution to tumour, intratumoural distribution and cell internalisation, and specific drug release. First, MMPs-sensitive polyethylene glycol (PEG) de-shielding and activatable cell penetrating peptides were developed to improve the blood circulation time of drug delivery systems, thereby, enhancing tumour or stroma cells recognition and penetration. Following tumour recognition, the MMPs-sensitive and size- or morphology-changeable nanoparticles (NPs) could highly accumulate and penetrate into tumour. Lastly, several MMPs-sensitive drug release strategies were feasible for both small molecule drugs and macromolecule drugs. In conclusion, recent novel advances of MMPs-responsive nanomaterials in tumour targeting diagnosis and treatment were highlighted in this review.