Self-Reinforced Cancer Targeting (SRCT) Depending on Reciprocally Enhancing Feedback between Targeting and Therapy.

Conventional cancer targeting methodology needs to be reformed to overcome the intrinsic barriers responsible for poor targeting efficiency. This study describes a concept of self-reinforced cancer targeting (SRCT) by correlating targeting with therapy in a reciprocally enhancing manner. SRCT is achieved on the basis of two prerequisites: (1) target molecules have to be expressed on cancer cell membranes but not on normal cells, and (2) notably, their expression on cancer cells must be actively upregulated in response to cellular attack by cancer treatments. As a proof-of-concept, a GRP78-targeting nanovehicle for chemotherapy was designed. Resultant data showed that chemotherapeutic drugs could effectively elevate GRP78 expression on the plasma membranes of cancer cells while having minimal influence on normal cells. DOX pretreatment of cancer cells and tumor tissues can greatly increase the targeting efficacy and therapeutic performance of the prepared GRP78-targeting nanomedicine while somewhat disfavoring the nontargeting counterpart. In vivo and in vitro results demonstrated that this GRP78-targeting nanomedicine could accurately target cancer cells to not only implement chemotherapy but also induce GRP78 upregulation on cancer cells, eventually benefiting continuous cancer-cell-targeted attack by the nanomedicines remaining in the blood circulation or administered in the next dose. The GRP78-targeting nanomedicine displays much better antitumor performance compared with the nontargeting counterpart. SRCT is expected to advance cancer-targeted therapy based on the positive dependency between targeting and therapeutic modalities.

Harnessing in situ glutathione for effective ROS generation and tumor suppression via nanohybrid-mediated catabolism dynamic therapy.

The overexpression of glutathione (GSH) in cancer cells has long been regarded as the primary obstacle for reactive oxygen species (ROS)-involved anti-tumor therapies. To solve this issue, a ferric ion and selenite-codoped calcium phosphate (Fe/Se-CaP) nanohybrid here is fabricated to catabolize endogenous GSH, instead of directly deleting it, to trigger a ROS storm for tumor suppression. The selenite component in Fe/Se-CaP can catabolize GSH to superoxide anion (O2•-) and hydroxyl radicals (•OH) via cascade catalytic reactions, elevating oxidative stress while destroying antioxidant system. The doped Fe can further catalyze the soaring hydrogen peroxide (H2O2) originated from O2•- to •OH via Fenton reactions. Collectively, Fe/Se-CaP mediated self-augmented catabolism dynamic therapy finally induces apoptosis of cancer cells owing to the significant rise of ROS and, combined with CaP adjuvant, evokes adaptive immune responses to suppress tumor progression, providing an innovative train of thought for ROS-involved anti-tumor therapies.

Multifunctional liquid metal-based nanoparticles with glycolysis and mitochondrial metabolism inhibition for tumor photothermal therapy.

Tumor cells obtain energy supply from different metabolic pathways to maintain survival. In this study, a tumor acidity-responsive spherical nanoparticle (called as LMGC) was designed by attaching glucose oxidase (GOx) and mineralizing calcium carbonate on the surface of liquid metal nanoparticles to integrate the synergistic effect of adenosine triphosphate (ATP) generation inhibition and photothermal therapy (PTT) for enhanced tumor therapy. After GOx catalysis, the process of glycolysis was inhibited, and the increased H2O2 level enhanced the intratumoral oxidative stress. Besides, the gluconic acid production accelerated the degradation of LMGC and promoted Ca2+-mediated mitochondrial dysfunction. The inhibition of glycolysis and mitochondrial metabolism could significantly reduce ATP production and down-regulate heat shock protein (HSP) expression, which would reduce tumor cells heat resistance and improve PTT therapeutic effect. This liquid metal-based ATP inhibition system with enhanced therapeutic effect will find great potential for tumor treatment.

Transformable Spinose Nanodrums with Self-Supplied H2 O2 for Photothermal and Cascade Catalytic Therapy of Tumor.

Advances in enzymes involve an efficient biocatalytic process, which has demonstrated great potential in biomedical applications. However, designing a functional carrier for enzymes equipped with satisfactory degradability and loading efficiency, remains a challenge. Here, based on transformable liquid metal (LM), a spinose nanodrum is designed as protein carrier to deliver enzyme for tumor treatment. With the assistance of spines and a special drum-like shape, it is found that the spiny LM can carry much more enzymes than spherical LM under the same condition. Benefiting from the satisfactory enzyme loading efficiency of spiny LM, a plasma amine oxidase immobilized spinose LM nanosystem enveloped with epigallocatechin gallate (EGCG)-Fe3+ (LMPE) is fabricated for photothermal and cascade catalytic tumor therapy. Activated by the acidic condition in the tumor microenvironment, the LMPE can oxidize spermine (Spm) and spermidine (Spd) to generate hydrogen peroxide (H2 O2 ) for Fenton catalytic reaction to produce the lethal hydroxyl radical (•OH) for tumor cell killing. Combined with remarkable photothermal performance of LM, LMPE exhibits significant inhibition of tumor in vivo.

Integration of a porous coordination network and black phosphorus nanosheets for improved photodynamic therapy of tumor.

Selectively attenuating the protection offered by heat shock protein 90 (HSP90), which is indispensable for the stabilization of the essential regulators of cell survival and works as a cell guardian under oxidative stress conditions, is a potential approach to improve the efficiency of cancer therapy. Here, we designed a biodegradable nanoplatform (APCN/BP-FA) based on a Zr(iv)-based porphyrinic porous coordination network (PCN) and black phosphorus (BP) sheets for efficient photodynamic therapy (PDT) by enhancing the accumulation of the nanoplatforms in the tumor area and attenuating the protection of cancer cells. Owing to the favorable degradability of BP, the nanosystem exhibited accelerated the release of the HSP90 inhibitor tanespimycin (17-AAG) and an apparent promotion in the reactive oxygen species (ROS) yield of PCN as well as expedited the degradation of the PCN-laden BP nanoplatforms. Both in vitro and in vivo results revealed that the elevated amounts of ROS and reduced cytoprotection in tumor cells were caused by the nanoplatforms. This strategy may provide a promising method for attenuating cytoprotection to aid efficient photodynamic therapy.

A MSN-based tumor-targeted nanoplatform to interfere with lactate metabolism to induce tumor cell acidosis for tumor suppression and anti-metastasis.

Lactate, the main contributor to the acidic tumor microenvironment, not only promotes the proliferation of tumor cells, but also closely relates to tumor invasion and metastasis. Here, a tumor targeting nanoplatform, designated as Me&Flu@MSN@MnO2-FA, was fabricated for effective tumor suppression and anti-metastasis by interfering with lactate metabolism of tumor cells. Metformin (Me) and fluvastatin sodium (Flu) were incorporated into MnO2-coated mesoporous silicon nanoparticles (MSNs), the synergism between Me and Flu can modulate the pyruvate metabolic pathway to produce more lactate, and concurrently inhibit lactate efflux to induce intracellular acidosis to kill tumor cells. As a result of the restricted lactate efflux, the extracellular lactate concentration is reduced, and the ability of the tumor cells to migrate is also weakened. This ingenious strategy based on Me&Flu@MSN@MnO2-FA showed an obvious inhibitory effect on tumor growth and resistance to metastasis.

pH-sensitive MOF integrated with glucose oxidase for glucose-responsive insulin delivery.

Glucose-responsive insulin delivery system mimicking the function of pancreatic ß-cells to maintain blood glucose homeostasis would effectively alleviate diabetes. Here, a new glucose-responsive delivery (ZIF@Ins&GOx) for self-regulated insulin release was constructed by encapsulating insulin and glucose oxidase (GOx) into pH-sensitive zeolitic imidazole framework-8 (ZIF-8) nanocrystals. After entering the cavities of ZIF-8, glucose can be oxidized into gluconic acid by GOx, causing a decrease in local pH. Then, ZIF-8 nanocrystals would be degraded under the acidic microenvironment that in turn triggers the release of insulin in a glucose responsive fashion. In vitro studies indicated that the biological activity of insulin could be protected by the rigid structure of ZIF-8 and the release of insulin could be modulated in response to glucose concentrations. In vivo experiments demonstrated that a single subcutaneous injection of the ZIF@Ins&GOx would facilitate the stabilization of blood glucose level of normoglycemic state for up to 72 h in type 1 diabetes (T1D). The multifunctional insulin delivery system shows a new proof-of-concept for T1D treatment by using ZIF-8 nanocrystals loaded with insulin and enzyme.

Hydrogen gas improves photothermal therapy of tumor and restrains the relapse of distant dormant tumor.

Inflammation during photothermal therapy (PTT) of tumor usually results in adverse consequences. Here, a biomembrane camouflaged nanomedicine (mPDAB) containing polydopamine and ammonia borane was designed to enhance PTT efficacy and mitigate inflammation. Polydopamine, a biocompatible photothermal agent, can effectively convert light into heat for PTT. Ammonia borane was linked to the surface of polydopamine through the interaction of hydrogen bonding, which could destroy redox homoeostasis in tumor cells and reduce inflammation by H2 release in tumor microenvironment. Owing to the same origin of outer biomembranes, mPDAB showed excellent tumor accumulation and low systemic toxicity in a breast tumor model. Excellent PTT efficacy and inflammation reduction made the mPDAB completely eliminate the primary tumors, while also restraining the outgrowth of distant dormant tumors. The biomimetic nanomedicine shows potentials as a universal inflammation-self-alleviated platform to ameliorate inflammation-related disease treatment, including but not limited to PTT for tumor.

Photo-controlled liquid metal nanoparticle-enzyme for starvation/photothermal therapy of tumor by win-win cooperation.

Here, a highly cooperative liquid metal nanoparticle-enzyme (LM@GOX) was constructed for combinational starvation/photothermal therapy of tumor. It was found that the enzyme activity of glucose oxidase (GOX) could be strengthened along with the increased temperature within a given range and its optimal activity is around about 43-60 °C. Utilizing the photothermal conversion ability of liquid metal (LM), the GOX catalytic efficiency could be photo-controlled with improved starvation therapeutic efficiency. Furthermore, due to the accelerating blood flow during the photothermal therapy (PTT), the hypoxic situation in tumor tissues could also be relieved, which would contribute to conquering the hypoxia-suppressed GOX catalysis. In the meanwhile, the severe thermo-resistance of tumor cells during PTT process could be overcome by GOX induced decrease of adenosine triphosphate (ATP) and heat shock proteins (HSPs) level, eventually leading to an improved therapeutic effect of PTT. Both in vitro and in vivo studies proved that LM@GOX could significantly inhibit the growth of solid tumor under NIR illumination by a win-win cooperative starvation/photothermal therapy.

Immobilized liquid metal nanoparticles with improved stability and photothermal performance for combinational therapy of tumor.

Various negative effects accompanying with the instability of bare liquid metal (LM) nanoparticles, including undesirable spontaneous coalescence, continuous photothermal performance deterioration and difficult multi-step functionalization, severely hinder its applications in biomedical area. In this study, we proposed a new concept of immobilized liquid metal nanoparticles based on a surface mesoporous silica coating strategy (LM@MSN). Strikingly, it was found that unsteady and vulnerable LM nanoparticles after immobilization exhibited enhanced stabilization and sustainable photothermal performance even with a long and repeated light irradiation in acidic environments. Moreover, integrating the properties of easy surface functionalization and high drug loading efficiency from silica shell, immobilized LM nanoparticle was further used for photothermal involved combinational therapy. The classical anticancer drug doxorubicin (DOX) was encapsulated in pores of silica shell and the hyaluronic acid (HA) was decorated on LM@MSN to construct LM@MSN/DOX@HA for tumor targeted combination therapy. Both in vitro and in vivo studies proved that LM@MSN/DOX@HA could significantly inhibit solid tumor growth under near infrared (NIR) irradiation by synergistic photothermal/chemotherapy.

Artificially Reprogrammed Macrophages as Tumor-Tropic Immunosuppression-Resistant Biologics to Realize Therapeutics Production and Immune Activation.

To engineer patient-derived cells into therapy-purposed biologics is a promising solution to realize personalized treatments. Without using gene-editing technology, a live cell-typed therapeutic is engineered for tumor treatment by artificially reprogramming macrophages with hyaluronic acid-decorated superparamagnetic iron oxide nanoparticles (HIONs). This nanoparticle-assisted cell-reprogramming strategy demonstrates profound advantages, due to the combined contributions from the biological regulation of HIONs and the intrinsic nature of macrophages. Firstly, the reprogrammed macrophages present a substantial improvement in their innate capabilities, such as more effective tumor targeting and more efficient generation of bioactive components (e.g., reactive oxygen species, bioactive cytokines) to suppress tumor growth. Furthermore, this cell therapeutic exhibits cytostatic/proapoptotic effects specific to cancer cells. Secondly, HIONs enable macrophages more resistant to the intratumoral immunosuppressive environment. Thirdly, the macrophages are endowed with a strong ability to prime in situ protumoral M2 macrophages into antitumor M1 phenotype in a paracrine-like manner. Consequently, a synergistic tumor-inhibition effect is achieved. This study shows that engineering nanomaterial-reprogrammed live cells as therapeutic biologics may be a more preferable option to the commonly used approaches where nanomaterials are administrated to induce bioresponse of certain cells in vivo.

Real-Time Imaging of Free Radicals for Mitochondria-Targeting Hypoxic Tumor Therapy.

Free radicals have emerged as new-type and promising candidates for hypoxic tumor treatment, and further study of their therapeutic mechanism by real-time imaging is of great importance to explore their biomedical applications. Herein, we present a smart free-radical generator AuNC-V057-TPP for hypoxic tumor therapy; the AuNC-V057-TPP not only exhibits good therapeutic effect under both hypoxic and normoxic conditions but also can monitor the release of free radicals in real-time both in vitro and in vivo. What is more, with the mitochondria-targeting ability, the AuNC-V057-TPP is demonstrated with improved antitumor efficacy through enhanced free radical level in mitochondria, which leads to mitochondrial membrane damage and ATP production reduction and finally induces cancer cell apoptosis.

Aggressive Man-Made Red Blood Cells for Hypoxia-Resistant Photodynamic Therapy.

Extreme hypoxia of tumors represents the most notable barrier against the advance of tumor treatments. Inspired by the biological nature of red blood cells (RBCs) as the primary oxygen supplier in mammals, an aggressive man-made RBC (AmmRBC) is created to combat the hypoxia-mediated resistance of tumors to photodynamic therapy (PDT). Specifically, the complex formed between hemoglobin and enzyme-mimicking polydopamine, and polydopamine-carried photosensitizer is encapsulated inside the biovesicle that is engineered from the recombined RBC membranes. The mean corpuscular hemoglobin of AmmRBCs reaches about tenfold as high as that of natural RBCs. Owing to the same origin of outer membranes, AmmRBCs share excellent biocompatibility with parent RBCs. The introduced polydopamine plays the role of the antioxidative enzymes existing inside RBCs to effectively prevent the oxygen-carrying hemoglobin from the oxidation damage during the circulation. This biomimetic engineering can accumulate in tumors, permit in situ efficient oxygen supply, and impose strong PDT efficacy toward the extremely hypoxic tumor with complete tumor elimination. The man-made pseudo-RBC shows potentials as a universal oxygen-self-supplied platform to sensitize hypoxia-limited tumor treatment means, including but not limited to PDT. Meanwhile, this study offers ideas to the production of artificial substitutes of packed RBCs for clinical blood transfusion.

Double-Targeting Explosible Nanofirework for Tumor Ignition to Guide Tumor-Depth Photothermal Therapy.

This study reports a double-targeting "nanofirework" for tumor-ignited imaging to guide effective tumor-depth photothermal therapy (PTT). Typically, ≈30 nm upconversion nanoparticles (UCNP) are enveloped with a hybrid corona composed of ≈4 nm CuS tethered hyaluronic acid (CuS-HA). The HA corona provides active tumor-targeted functionality together with excellent stability and improved biocompatibility. The dimension of UCNP@CuS-HA is specifically set within the optimal size window for passive tumor-targeting effect, demonstrating significant contributions to both the in vivo prolonged circulation duration and the enhanced size-dependent tumor accumulation compared with ultrasmall CuS nanoparticles. The tumors featuring hyaluronidase (HAase) overexpression could induce the escape of CuS away from UCNP@CuS-HA due to HAase-catalyzed HA degradation, in turn activating the recovery of initially CuS-quenched luminescence of UCNP and also driving the tumor-depth infiltration of ultrasmall CuS for effective PTT. This in vivo transition has proven to be highly dependent on tumor occurrence like a tumor-ignited explosible firework. Together with the double-targeting functionality, the pathology-selective tumor ignition permits precise tumor detection and imaging-guided spatiotemporal control over PTT operation, leading to complete tumor ablation under near infrared (NIR) irradiation. This study offers a new paradigm of utilizing pathological characteristics to design nanotheranostics for precise detection and personalized therapy of tumors.

A metal-semiconductor nanocomposite as an efficient oxygen-independent photosensitizer for photodynamic tumor therapy.

Photodynamic therapy (PDT) is regarded as one of the most promising cancer treatments, and oxygen-independent photosensitizers have been intensively explored for advancing the development of PDT. Here, we reported on a superior hybrid nanocomposite (HNC) consisting of a metal (Au deposition) and a semiconductor (CdSe-seeded/CdS nanorods) as a photosensitizer. Under visible light, the photogenerated holes were three-dimensionally confined to the CdSe quantum dots and the delocalized electrons were transferred to the Au tips, which provided hydrogen and oxygen evolution sites for water splitting to generate reactive oxygen species (ROS) with no need for oxygen participation. Compared with semiconductors without deposited metal (i.e. raw CdSe-seeded/CdS nanorods (NRs)) under a normoxic or hypoxic environment, the HNCs exhibited substantially enhanced light-triggered ROS generation in vitro. After being modified with an Arg-Gly-Asp (RGD) peptide sequence, the nanocomposite was deemed as a tumor-targeting, long-lived and oxygen-independent photosensitizer with promoted PDT efficiency for in vivo anti-tumor therapy. This oxygen-independent nanocomposite successfully overcame the hypoxia-related PDT resistance by water splitting, which opened a window to develop conventional semiconductors as photosensitizers for effective PDT.