Inflammation-Driven Nanohitchhiker Enhances Postoperative Immunotherapy by Alleviating Prostaglandin E2-Mediated Immunosuppression.

Inflammation contributes to the immunosuppressive microenvironment and leads to the recurrence of surgically resected tumors. The COX-2/PGE2 axis is considered a key player in shaping the immunosuppression microenvironment. However, targeted modulation of the postoperative tumor microenvironment is challenging. To specifically curb the inflammation and alleviate immunosuppression, here, we developed a PGE2 inhibitor celecoxib (CXB)-loaded bionic nanoparticle (CP@CM) coated with activated murine vascular endothelial cell (C166 cells) membrane to target postoperative melanoma and inhibit its recurrence. CP@CM adhered to inflammatory white blood cells (WBCs) through the adhesion molecules, including ICAM-1, VCAM-1, E-selectin, and P-selection, expressed on the surface of C166 cells. Leveraging the natural tropism of the WBC to the inflammatory postoperative tumor site, CP@CM efficiently targeted postoperative tumors. In melanoma postoperative recurrence models, CXB significantly reduced PGE2 secretion and the recruitment of immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Treg) by inhibiting the activity of COX-2. This was followed by an increase in the infiltration of CD8+ T cells and CD4+ T cells in tumor tissues. Additionally, the immune responses were further enhanced by combining a PD-L1 monoclonal antibody. Ultimately, this immunotherapeutic strategy reversed the tumor immunosuppressive microenvironment and inhibited tumor recurrence, demonstrating a promising potential for postoperative immunotherapy for melanoma.

Albumin-Hitchhiking Drug Delivery to Tumor-Draining Lymph Nodes Precisely Boosts Tumor-Specific Immunity through Autophagy Modulation of Immune Cells.

Tumor-draining lymph nodes (TDLNs) are the first sites where tumor components reach and dendritic cells (DCs) present tumor-associated antigens to T cells. DCs rely on autophagy to process tumor antigens into epitope peptides to form epitope-MHC complexes. Selective delivery of autophagy-stimulating drugs to TDLNs may be a precise strategy to boost chemotherapy-induced antitumor immunity. Here, a multistage stimulating strategy is proposed to activate the antitumor immunity cascade by inducing immunogenic death of tumor cells and elevating antigen presentation of DCs in TDLNs. A tumor-microenvironment-responsive "albumin-hitchhiking" micelle is established by self-assembling tumor-targeting oxaliplatin prodrug and lipophilized trehalose prodrug. This demonstrates that lipophilic modification of trehalose with a DSPE tail and the precise exposure in the tumor site enhances its binding to endogenous albumin and realizes TDLNs-selective reflux, where it upregulates antigen processing and presentation of DCs. This study introduces an approach for targeted delivery to TDLNs and provides insights into mechanisms of autophagy in tumor-specific immunity.

Micellar nanoparticles inhibit breast cancer and pulmonary metastasis by modulating the recruitment and depletion of myeloid-derived suppressor cells.

Myeloid-derived suppressor cells (MDSCs) are notorious for their pathological characteristics of immunosuppression and their promoting effect on cancers. They can induce the formation of pre-metastatic niche (PMN) characterized by inflammation, immunosuppression and vascular leakage, and promote pulmonary metastasis of breast cancer. Herein, a tumor targeting c(RGDfk) peptide modified low molecular-weight-heparin-all-trans-retinoic-acid (LMWH-ATRA) micellar nanoparticle loaded with chemotherapeutic drug doxorubicin (DOX) and immune adjuvant α-galactosylceramide (αGC) (RLA/DOX/αGC NP) was developed. The hydrophilic segment LMWH inhibited the recruitment of MDSCs by competitively binding with P-selectin on the surface of vascular endothelial cells (VECs), while the hydrophobic segment ATRA promoted the depletion of MDSCs by inducing their differentiation. Through the modulation of MDSCs, micelles can significantly improve the inflammatory and immunosuppressive microenvironment of the lung and tumor sites, and inhibit the formation of PMN. Not only this, the micelles also produced a synergistic effect with αGC, which effectively improved the anti-tumor immunity of tumor bearing mice and provided a promising therapeutic strategy for breast cancer and pulmonary metastasis.

Micellar nanoparticles inhibit the postoperative inflammation, recurrence and pulmonary metastasis of 4T1 breast cancer by blocking NF-κB pathway and promoting MDSCs depletion.

The progression of breast cancer can stimulate the production of myeloid-derived suppressor cells (MDSCs). These cells with significant immunosuppressive activity play a key role in promoting the formation of pulmonary inflammatory and immunosuppressive microenvironment, namely pre-metastatic niche (PMN). Surgical resection of tumors often leads to strong inflammatory reactions, and the produced circulating tumor cells (CTCs) can implant into PMN to promote the recurrence and pulmonary metastasis of breast cancer. Therefore, we developed a hyaluronic acid (HA)-coated chitosan oligosaccharide-all-trans-retinoic-acid (COS-ATRA) micellar nanoparticle loaded with chemotherapeutic drug doxorubicin (DOX) (HA@CA/DOX NPs). The hydrophilic segment COS and hydrophobic segment ATRA both blocked NF-κB inflammatory signaling pathway in 4T1 tumor cells and MDSCs and alleviated the inflammation after resection. Besides, ATRA also significantly depleted MDSCs in lungs and tumors, thereby regulating the inflammatory and immunosuppressive microenvironment and inhibiting the formation of PMN. HA coated on the surface of nanoparticles shielded the excessive positive charge and achieved tumor targeting through CD44 on the surface of tumor cells. This drug delivery system combined with anti-inflammation and chemotherapy significantly inhibited the postoperative recurrence and pulmonary metastasis of breast cancer.

Metabolic reprogramming by dual-targeting biomimetic nanoparticles for enhanced tumor chemo-immunotherapy.

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

A neutrophil-mediated carrier regulates tumor stemness by inhibiting autophagy to prevent postoperative triple-negative breast cancer recurrence and metastasis.

Recurrence and metastasis after resection are still the main challenges in clinical treatment of breast cancer. Residual tumor and cancer stem-like cells are the primary culprits of recurrence and metastasis. Recent research studies indicate that autophagy is a cytoprotective mechanism of tumors, which maintains the stemness of cancer cells and promotes tumor proliferation and metastasis. Here, we constructed a "Trojan horse" using neutrophils as the carrier (PH-RL@NEs) to prevent the recurrence and metastasis of postoperative breast cancer. Neutrophils, as a "Trojan horse," can quickly respond to postoperative inflammation and accurately deliver drugs to the residual tumor site. The inflammation-triggered "Trojan horse" was then opened to release the liposomes containing the chemotherapeutic drug paclitaxel (PTX) and the autophagy inhibitor hydroxychloroquine (HCQ). We found that HCQ could effectively inhibit tumor cell autophagy, interfere with tumor epithelial-mesenchymal transition, and reduce the tumor stem cell-like population. In the orthotopic 4T1 postoperative recurrence models, PTX and HCQ synergistically killed tumors and regulated the stemness of tumor cells, thereby significantly inhibiting tumor recurrence and metastasis. Our work proved that the inhibition of autophagy to reduce tumor stemness is feasible and effective, which opens up a new prospect for postoperative tumor treatment. STATEMENT OF SIGNIFICANCE: The present study aimed to solve the issues of postoperative recurrence and metastasis of breast cancer and low efficiency of drug administration after surgery. For this purpose, we constructed neutrophils containing hydroxychloroquine (HCQ) and paclitaxel (PTX) co-loaded liposomes (PH-RL@NEs), which for the first time regulated the stemness of tumor cells by inhibiting autophagy, thereby inhibiting postoperative recurrence and metastasis of breast cancer cells. The results showed that PH-RL@NEs enhanced the targeted drug delivery efficiency, with the help of postoperative inflammation chemotaxis of neutrophils. HCQ effectively inhibited autophagy of tumor cells and reduced tumor stem cell-like cells, thus improving the therapeutic effect in the 4T1 in situ postoperative recurrence model.

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

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

Co-delivery of autophagy inhibitor and gemcitabine using a pH-activatable core-shell nanobomb inhibits pancreatic cancer progression and metastasis.

Background: Metastasis is one of the main reasons for the high mortality associated with pancreatic ductal adenocarcinoma (PDAC), and autophagy regulates the metastatic migration of tumor cells, their invasion of tissues, and their formation of focal adhesions. Inhibiting autophagy may suppress tumor growth and metastasis, but the abundant extracellular matrix hinders the deep penetration of therapeutic agents. Methods: To enhance the penetration of drugs that can inhibit metastasis of pancreatic cancer, a pH-responsive drug delivery system was formulated. Gemcitabine (GEM), a first-line chemotherapeutic drug against PDAC, was loaded in 6PA-modified DGL (PDGL) nanoparticles to afford PDGL-GEM. Then PDGL-GEM was co-precipitated with the autophagy inhibitor chloroquine phosphate (CQ) and calcium phosphate to formulate PDGL-GEM@CAP/CQ. The size and morphology of the resulting "nanobomb" PDGL-GEM@CAP/CQ were characterized, and their uptake into cells, cytotoxicity and ability to inhibit autophagy were analyzed at pH 6.5 and 7.4. The anti-tumor and anti-metastasis effects of the nanobomb were explored on mice carrying Pan 02 pancreatic tumor xenografts or orthotopic tumors. Results: The pH-induced dissolution of calcium phosphate facilitated the release of CQ from the nanobomb and deep penetration of PDGL-GEM. The internalization of PDGL-GEM and subsequent intracellular release of GEM inhibited tumor growth, while CQ downregulated autophagy in tumor cells and fibroblasts. In fact, inhibition of xenograft and orthotopic tumor growth was greater with the complete PDGL-GEM@CAP/CQ than with subassemblies lacking GEM or CQ. More importantly, mechanistic studies in vitro and in vivo suggested that the nanobomb inhibits metastasis by downregulating MMP-2 and paxillin, as well as reducing fibrosis. Conclusion: The pH-sensitive PDGL-GEM@CAP/CQ shows potential for inhibiting proliferation and metastasis of pancreatic cancer through an autophagy-dependent pathway.

Macrophage-mediated multi-mode drug release system for photothermal combined with anti-inflammatory therapy against postoperative recurrence of triple negative breast cancer.

Surgery combined with postoperative treatment is a widely accepted therapeutic strategy against breast cancer. Macrophage-based carriers have been proved to be an effective postoperative drug delivery system due to their inflammatory tendency. However, the slow and incomplete release of the cargo and the postoperative inflammation remain to be solved. Here, we described a macrophage-mediated photothermal therapy combined with anti-inflammatory strategy to inhibit breast cancer postoperative relapse. The anti-inflammatory resveratrol and photothermal agent indocyanine green (ICG) were loaded in octaarginine (R8)-modified liposomes, then ingested by macrophages to form the macrophage-based drug delivery system (Res/ICG-R8-Lip@MP). Res/ICG-R8-Lip@MP showed effective tumor-targeting ability via inflammatory tropism of macrophages and excellent near-infrared (NIR) photothermal performance. In vitro experiments showed that the carrier could not only trigger drug release though inflammation, but also utilize the photothermal conversion property to destroy the macrophage-based carrier at the local tumor to maximize drug release. In vivo experiments indicated that Res/ICG-R8-Lip@MP ablated residual tumor tissues and reduced the postoperative inflammation, and at the same time achieved significant effect of inhibiting tumor postoperative relapse. This synergistic photothermal and anti-inflammatory strategy has great potential in postoperative treatment of breast cancer.

Shield and sword nano-soldiers ameliorate rheumatoid arthritis by multi-stage manipulation of neutrophils.

Rheumatoid arthritis (RA) is characterized by the outbreak of inflammation. Neutrophils, the main culprit of the outbreak of inflammation, are the first inflammatory cells to be recruited to inflamed joints and facilitate the recruitment of themselves by stimulating the release of chemokines. Here, based on neutrophils, a novel anti-inflammatory "shield and sword soldiers" strategy is established with LMWH-TOS nanoparticles (LT NPs). The hydrophilic fragment low molecular weight heparin (LMWH) acts as a shield which block the transvascular movement of neutrophils through inhibiting the adhesion cascade by binding to P-selectin on inflamed endothelium. Synergistically, MMP-9, which is secreted by the recruited neutrophils and degrade the main component of articular cartilage, is reduced by the hydrophobic fragment d-α-tocopheryl succinate (TOS), functioning as a sword. In collagen-induced arthritis (CIA) mouse model, LT NPs show significant targeting effect, and exhibit prominent therapeutic efficacy after enveloping the first-line anti-RA drug methotrexate. Our work proves that the multi-stage manipulation of neutrophils is feasible and effective, providing a new concept for RA treatment.

Multifunctional self-delivery micelles targeting the invasion-metastasis cascade for enhanced chemotherapy against melanoma and the lung metastasis.

Metastasis is closely related to the high mortality of cancer patients, which is regulated by multiple signaling pathways. Hence, multiphase blocking of this biological process is beneficial for cancer treatments. Herein, we establish a multifunctional self-delivering system by synthesizing D-α-tocopheryl succinates (TOS)-conjugated chondroitin sulfate (CS) (CT NPs), which both serve as nanocarrier and antimetastatic agent that affects different phases of the metastatic cascade. TOS as the hydrophobic segment of CT NPs can inhibit the secretion of matrix metalloproteinase-9, while the hydrophilic segment CS targets B16F10 cells through CD44 receptors and reduces the interaction between tumor cells and platelets. The results show that CT NPs are able to inhibit metastasis successfully both in vitro and in vivo by interfering the multiphase of the metastatic cascade. Following encapsulating chemotherapeutic drug doxorubicin (DOX), the obtained micelles CT/DOX efficiently suppress both primary-tumor growth and metastases in B16F10 bearing mice. As a result, the rationally designed multifunctional NPs composing of biocompatible materials provide excellent therapeutic effects on solid tumors and metastases.

A "dual-guide" bioinspired drug delivery strategy of a macrophage-based carrier against postoperative triple-negative breast cancer recurrence.

Recurrence after tumor resection is mainly caused by post-operative inflammation and residual cancer cells, which is a serious obstacle to breast cancer treatment. Traditional nanoparticles rely primarily on the enhanced permeability and retention (EPR) effect in well-vascularized tumors. In this study, a macrophage-based carrier is designed to enhance the efficiency of targeting to recurrent tumors through a "dual-guide" strategy. After tumor resection, a burst of inflammatory factors occurs in the resection wound, which can recruit monocytes/macrophages rapidly. Combined with the tropism of monocyte chemoattractant protein, a large number of macrophage-mediated carriers will be recruited to surgical recurrence sites. Octaarginine (RRRRRRRR, R8)-modified liposomes in macrophages contain two agents with different pharmacological mechanisms, paclitaxel (PTX) and resveratrol (Res), which have enhanced therapeutic effects. In vitro study demonstrated that macrophage-mediated carriers approach 4 T1 cells through an inflammatory gradient and reach recurrence tumors through a "dual-guide" strategy. Then, membrane fusion and inflammation-triggered release deliver the drug into the recurrent tumor cells. In vivo experiments show that macrophage-based carriers exhibit effective tumor-targeting ability, especially in post-operation situations. More importantly, macrophage-mediated liposomes encapsulated with PTX and Res inhibit tumor recurrence in both ectopic and orthotopic 4 T1 post-operative recurrence models.

On-Demand Autophagy Cascade Amplification Nanoparticles Precisely Enhanced Oxaliplatin-Induced Cancer Immunotherapy.

Chemoimmunotherapy-induced antitumor immune response is highly dependent on tumor autophagy. When tumor cells are treated with chemoimmunotherapy, timely overactivated autophagy can not only lead more tumor cells to death, but also participate in the endogenous antigen presentation and immune stimulators secretion of dying cells, thus plays a vital role. However, timely and accurately overactivated tumor autophagy during chemoimmunotherapy is of great difficulty. Here, an on-demand autophagy cascade amplification nanoparticle (ASN) is reported to boost oxaliplatin-induced cancer immunotherapy. ASN is prepared by self-assemble of autophagy-responsible C-TFG micelle and is followed by electrostatic binding of oxaliplatin prodrug (HA-OXA). After entering tumor cells, the HA-OXA shell of ASN first responds to the reduction microenvironment and releases oxaliplatin to trigger tumor immunogenic cell death and mildly stimulates tumor autophagy. Then, the exposed C-TFG micelle can sensitively respond to oxaliplatin-induced autophagy and release a powerful autophagy inducer STF-62247, which precisely transforms autophagy to "overactivated" condition, leading tumor cells to autophagic death and enhance subsequent tumor antigen processing of the dying cells. In CT26 tumor-bearing mice, ASN exhibits optimal immune stimulation and antitumor efficiency due to its on-demand autophagy induction ability.

Remodeling tumor immune microenvironment via targeted blockade of PI3K-γ and CSF-1/CSF-1R pathways in tumor associated macrophages for pancreatic cancer therapy.

Immunotherapy has exhibited great potential in cancer treatment. However, for immunosuppressive tumors such as pancreatic cancer, immunotherapy is far from satisfactory. PI3K-γ and colony stimulating factor-1/colony stimulating factor-1 receptor (CSF-1/CSF-1R) pathways are involved in the infiltration and polarization of immunosuppressive cells including M2 tumor associated macrophages (M2 TAMs), causing a suppressive tumor immune microenvironment (TIME) in pancreatic cancer. Herein, a M2 TAM targeting nanomicelle was developed to co-deliver PI3K-γ inhibitor NVP-BEZ 235 and CSF-1R-siRNA for specific TAMs reprogramming and antitumor immune responses activation. M2 TAM targeting peptide M2pep was modified on a mixed micelle, which was potent to co-encapsulate BEZ 235 and CSF-1R siRNA. The formulated nanomicelle increased M2 TAM targeting efficiency both in vitro and in vivo. Compared with single pathway blockade, dual blockade of PI3k-γ and CSF-1R demonstrated enhanced TAM remodeling effects by reducing M2 TAM level and elevating M1 TAM level, and also suppressed tumor infiltration of myeloid-derived suppressor cells (MDSCs). Consequently, the M2 TAM targeting reprogramming system activated antitumor immune responses and achieved enhanced anti-pancreatic tumor effects via PI3K-γ blockade and downregulation of CSF-1R. The M2pep modified nanomicelle provides a promising method for co-delivery of siRNA and small molecule inhibitor to M2 TAM. Dual inhibition of both PI3K-γ and CSF-1R can remodel TIME and activate antitumor immune responses synergistically, providing an alternative approach for pancreatic cancer treatment.

Enhanced anti-tumor and anti-metastasis therapy for triple negative breast cancer by CD44 receptor-targeted hybrid self-delivery micelles.

Tumor growth and metastasis are multistep processes regulated by multiple signaling pathways. The successful treatment of cancer largely depends on the ability to inhibit metastatic process. Multiphase inhibition of metastasis is a promising approach. Here, we described a targeting delivery system which was constructed by mixing hyaluronic acid-d-α-tocopheryl succinate (HA-TOS, HT) and low molecular weight heparin-TOS (LMWH-TOS, LT) to form a stable hybrid micelle (HT-LT), encapsulating chemotherapeutic drug doxorubicin (DOX). The prepared HT-LT NPs was about 125 nm in diameter with high drug encapsulation rate and continuous drug release behavior. We confirmed that HT-LT NPs exhibited an effective targeting ability both in vitro and in vivo using a 4T1 model that was attributed to HA binding to CD44 receptors. In addition, HT-LT NPs acted on different phases of the invasion-metastasis cascade and inhibited tumor cell migration and invasion, thus inhibiting tumor metastasis. This combinatorial strategy provided an alternative approach for triple negative breast cancer therapy.

Enhanced Melanoma-Targeted Therapy by "Fru-Blocked" Phenyboronic Acid-Modified Multiphase Antimetastatic Micellar Nanoparticles.

Metastasis remains the main driver of mortality in patients suffering from cancer because of the refractoriness resulting from the multi-phase metastatic cascade. Herein, a multifunctional self-delivering PBA-LMWH-TOS nanoparticle (PLT NP) is established that acts as both nanocarrier and anti-metastatic agent with effects on most hematogenous metastases of cancers. The hydrophilic segment (low molecular weight heparin, LMWH) inhibits the interactions between tumor cells and platelets. The hydrophobic segment (d-α-tocopheryl succinate, TOS) could inhibit the expression of matrix metalloproteinase-9 (MMP-9) in B16F10 cells which is first reported in this article. Surprisingly, even the blank NPs showed excellent anti-metastatic capacity in three mouse models by acting on different phases of the metastatic cascade. Moreover, the overexpression of sialic acid (SA) residues on tumor cells is implicated in the malignant and metastatic phenotypes of cancers. Thus, these 3-aminophenylboronic acid (PBA)-modified doxorubicin (DOX)-loaded NPs offer an efficient approach for the treatment of both solid melanomas and metastases. Furthermore, a simple pH-sensitive "Fructose (Fru)-blocking" coping strategy is established to reduce the NP distribution in normal tissues and distinctly increases the accumulation in melanoma tumors. These micellar NPs consisting of biocompatible materials offer a promising approach for the clinical therapy of highly invasive solid tumors and metastases.