Titania-Coated Gold Nano-Bipyramids for Blocking Autophagy Flux and Sensitizing Cancer Cells to Proteasome Inhibitor-Induced Death

Tanshinone I improves TNBC chemosensitivity by suppressing late-phase autophagy through AKT/p38 MAPK signaling pathway

The inhibition of autophagy is a potential therapeutic strategy to improve the chemosensitivity of triple-negative breast cancer (TNBC). In this study, we demonstrated that a natural terpenoid tanshinone I (TAN) enhanced the effectiveness of paclitaxel (PTX), at least in part, through an autophagy-dependent mechanism against TNBC. In vitro validation demonstrated that the combined therapy resulted in a synergistic decrease in the growth of TNBC cells. The chemosensitizing impact of TAN might be attributed to its inhibition of PTX-induced autophagy in the late phase by obstructing the fusion of autophagosomes and lysosomes, rather than by inhibiting lysosomal function. The findings from KEGG pathway analysis and molecular docking suggested that TAN might impact breast cancer chemoresistance primarily through the PI3K-Akt and MAPK signaling pathways. The non-canonical AKT/p38 MAPK signaling was further validated as the primary mechanism responsible for the inhibition of autophagy by TAN. In vivo study showed that the combined administration of TAN and PTX demonstrated a more significant suppression of tumor growth and autophagic activity compared to PTX monotherapy in the MDA-MB-231 xenograft nude mouse model. The safety evaluation of TAN in a zebrafish model, along with in vitro and in vivo validation, provided experimental and pre-clinical data supporting its potential as a natural adjunctive therapy in TNBC. Overall, this study suggests that the combination of TAN with PTX could provide an effective treatment option for advanced breast cancer, and targeting the AKT/p38 MAPK/late-autophagy signaling axis may be a promising approach for developing therapeutic interventions against TNBC.

Nanotherapeutics targeting autophagy regulation for improved cancer therapy

The clinical efficacy of current cancer therapies falls short, and there is a pressing demand to integrate new targets with conventional therapies. Autophagy, a highly conserved self-degradation process, has received considerable attention as an emerging therapeutic target for cancer. With the rapid development of nanomedicine, nanomaterials have been widely utilized in cancer therapy due to their unrivaled delivery performance. Hence, considering the potential benefits of integrating autophagy and nanotechnology in cancer therapy, we outline the latest advances in autophagy-based nanotherapeutics. Based on a brief background related to autophagy and nanotherapeutics and their impact on tumor progression, the feasibility of autophagy-based nanotherapeutics for cancer treatment is demonstrated. Further, emerging nanotherapeutics developed to modulate autophagy are reviewed from the perspective of cell signaling pathways, including modulation of the mammalian target of rapamycin (mTOR) pathway, autophagy-related (ATG) and its complex expression, reactive oxygen species (ROS) and mitophagy, interference with autophagosome-lysosome fusion, and inhibition of hypoxia-mediated autophagy. In addition, combination therapies in which nano-autophagy modulation is combined with chemotherapy, phototherapy, and immunotherapy are also described. Finally, the prospects and challenges of autophagy-based nanotherapeutics for efficient cancer treatment are envisioned.

All Roads Lead to Rome: Comparing Nanoparticle- and Small Molecule-Driven Cell Autophagy

Autophagy, vital for removing cellular waste, is triggered differently by small molecules and nanoparticles. Small molecules, like rapamycin, non-selectively activate autophagy by inhibiting the mTOR pathway, which is essential for cell regulation. This can clear damaged components but may cause cytotoxicity with prolonged use. Nanoparticles, however, induce autophagy, often causing oxidative stress, through broader cellular interactions and can lead to a targeted form known as "xenophagy." Their impact varies with their properties but can be harnessed therapeutically. In this review, the autophagy induced by nanoparticles is explored and small molecules across four dimensions: the mechanisms behind autophagy induction, the outcomes of such induction, the toxicological effects on cellular autophagy, and the therapeutic potential of employing autophagy triggered by nanoparticles or small molecules. Although small molecules and nanoparticles each induce autophagy through different pathways and lead to diverse effects, both represent invaluable tools in cell biology, nanomedicine, and drug discovery, offering unique insights and therapeutic opportunities.

Exploiting Nanotechnology for Drug Delivery: Advancing the Anti-Cancer Effects of Autophagy-Modulating Compounds in Traditional Chinese Medicine

Background

Cancer continues to be a prominent issue in the field of medicine, as demonstrated by recent studies emphasizing the significant role of autophagy in the development of cancer. Traditional Chinese Medicine (TCM) provides a variety of anti-tumor agents capable of regulating autophagy. However, the clinical application of autophagy-modulating compounds derived from TCM is impeded by their restricted water solubility and bioavailability. To overcome this challenge, the utilization of nanotechnology has been suggested as a potential solution. Nonetheless, the current body of literature on nanoparticles delivering TCM-derived autophagy-modulating anti-tumor compounds for cancer treatment is limited, lacking comprehensive summaries and detailed descriptions.

Methods

Up to November 2023, a comprehensive research study was conducted to gather relevant data using a variety of databases, including PubMed, ScienceDirect, Springer Link, Web of Science, and CNKI. The keywords utilized in this investigation included "autophagy", "nanoparticles", "traditional Chinese medicine" and "anticancer".

Results

This review provides a comprehensive analysis of the potential of nanotechnology in overcoming delivery challenges and enhancing the anti-cancer properties of autophagy-modulating compounds in TCM. The evaluation is based on a synthesis of different classes of autophagy-modulating compounds in TCM, their mechanisms of action in cancer treatment, and their potential benefits as reported in various scholarly sources. The findings indicate that nanotechnology shows potential in enhancing the availability of autophagy-modulating agents in TCM, thereby opening up a plethora of potential therapeutic avenues.

Conclusion

Nanotechnology has the potential to enhance the anti-tumor efficacy of autophagy-modulating compounds in traditional TCM, through regulation of autophagy.

The Emerging Landscape for Combating Resistance Associated with Energy-Based Therapies via Nanomedicine

Cancer represents a serious disease with significant implications for public health, imposing substantial economic burden and negative societal consequences. Compared to conventional cancer treatments, such as surgery and chemotherapy, energy-based therapies (ET) based on athermal and thermal ablation provide distinct advantages, including minimally invasive procedures and rapid postoperative recovery. Nevertheless, due to the complex pathophysiology of many solid tumors, the therapeutic effectiveness of ET is often limited. Nanotechnology offers unique opportunities by enabling facile material designs, tunable physicochemical properties, and excellent biocompatibility, thereby further augmenting the outcomes of ET. Numerous nanomaterials have demonstrated the ability to overcome intrinsic therapeutic resistance associated with ET, leading to improved antitumor responses. This comprehensive review systematically summarizes the underlying mechanisms of ET-associated resistance (ETR) and highlights representative applications of nanoplatforms used to mitigate ETR. Overall, this review emphasizes the recent advances in the field and presents a detailed account of novel nanomaterial designs in combating ETR, along with efforts aimed at facilitating their clinical translation.

A pro-death autophagy-based nanoplatform for enhancing antitumour efficacy with improved immune responses

Due to the pro-survival effect of mild autophagy, the therapeutic effect of chemo-immunotherapy is unsatisfactory. In addition, the adverse tumour microenvironment (TME), including the lack of antigen presentation, the deficiency of oxygen supply and immunosuppressive cells, results in immune escape and metastasis. Herein, a novel nanoplatform (CS-3BP/PA@DOX) based on the autophagy cascade is proposed for the first time to deliver the chemotherapeutic doxorubicin (DOX) and respiration inhibitor 3-bromopyruvic acid (3BP) to overcome the above obstacles. CS-3BP/PA@DOX exerts a synergistic therapeutic effect to initiate pro-death autophagy and facilitate the antigen presentation process by combining DOX chemotherapy and starvation therapy with 3BP. Additionally, CS-3BP/PA@DOX remodelled the immunosuppressive TME by alleviating hypoxia, damaging dense ECM, and downregulating PD-L1 to enhance antitumour immunity. 3BP was found to promote GSH depletion by inhibiting respiration for the first time, which reduces the chemical resistance of cancer and increases the sensitivity of cells to ROS, providing a new therapeutic direction of 3BP for antitumour treatment. Collectively, this study offers an opportunity to magnify pro-death autophagy, augment antitumour efficacy, facilitate anti-metastatic effects, and boost immune responses.

Nanomedicine for cancer targeted therapy with autophagy regulation

Nanoparticles have unique physical and chemical properties and are currently widely used in disease diagnosis, drug delivery, and new drug development in biomedicine. In recent years, the role of nanomedical technology in cancer treatment has become increasingly obvious. Autophagy is a multi-step degradation process in cells and an important pathway for material and energy recovery. It is closely related to the occurrence and development of cancer. Because nanomaterials are highly targeted and biosafe, they can be used as carriers to deliver autophagy regulators; in addition to their favorable physicochemical properties, nanomaterials can be employed to carry autophagy inhibitors, reducing the breakdown of chemotherapy drugs by cancer cells and thereby enhancing the drug's efficacy. Furthermore, certain nanomaterials can induce autophagy, triggering oxidative stress-mediated autophagy enhancement and cell apoptosis, thus constraining the progression of cancer cells.There are various types of nanoparticles, including liposomes, micelles, polymers, metal-based materials, and carbon-based materials. The majority of clinically applicable drugs are liposomes, though other materials are currently undergoing continuous optimization. This review begins with the roles of autophagy in tumor treatment, and then focuses on the application of nanomaterials with autophagy-regulating functions in tumor treatment.

Autophagy inhibitors for cancer therapy: Small molecules and nanomedicines

Autophagy is a conserved process in which the cytosolic materials are degraded and eventually recycled for cellular metabolism to maintain homeostasis. The dichotomous role of autophagy in pathogenesis is complicated. Accumulating reports have suggested that cytoprotective autophagy is responsible for tumor growth and progression. Autophagy inhibitors, such as chloroquine (CQ) and hydroxychloroquine (HCQ), are promising for treating malignancies or overcoming drug resistance in chemotherapy. With the rapid development of nanotechnology, nanomaterials also show autophagy-inhibitory effects or are reported as the carriers delivering autophagy inhibitors. In this review, we summarize the small-molecule compounds and nanomaterials inhibiting autophagic flux as well as the mechanisms involved. The nanocarrier-based drug delivery systems for autophagy inhibitors and their distinct advantages are also described. The progress of autophagy inhibitors for clinical applications is finally introduced, and their future perspectives are discussed.

Bioactive inorganic nanomaterials for cancer theranostics

Bioactive materials are a special class of biomaterials that can react in vivo to induce a biological response or regulate biological functions, thus achieving a better curative effect than traditional inert biomaterials. For cancer theranostics, compared with organic or polymer nanomaterials, inorganic nanomaterials possess unique physical and chemical properties, have stronger mechanical stability on the basis of maintaining certain bioactivity, and are easy to be compounded with various carriers (polymer carriers, biological carriers, etc.), so as to achieve specific antitumor efficacy. After entering the nanoscale, due to the nano-size effect, high specific surface area and special nanostructures, inorganic nanomaterials exhibit unique biological effects, which significantly influence the interaction with biological organisms. Therefore, the research and applications of bioactive inorganic nanomaterials in cancer theranostics have attracted wide attention. In this review, we mainly summarize the recent progress of bioactive inorganic nanomaterials in cancer theranostics, and also introduce the definition, synthesis and modification strategies of bioactive inorganic nanomaterials. Thereafter, the applications of bioactive inorganic nanomaterials in tumor imaging and antitumor therapy, including tumor microenvironment (TME) regulation, catalytic therapy, gas therapy, regulatory cell death and immunotherapy, are discussed. Finally, the biosafety and challenges of bioactive inorganic nanomaterials are also mentioned, and their future development opportunities are prospected. This review highlights the bioapplication of bioactive inorganic nanomaterials.

Autophagy-Targeted Calcium Phosphate Nanoparticles Enable Transarterial Chemoembolization for Enhanced Cancer Therapy

Transarterial chemoembolization (TACE) is commonly used for treating advanced hepatocellular carcinoma (HCC). However, the instability of lipiodol-drug emulsion and the altered tumor microenvironment (TME, such as hypoxia-induced autophagy) postembolization are responsible for the unsatisfactory therapeutic outcomes. Herein, pH-responsive poly(acrylic acid)/calcium phosphate nanoparticles (PAA/CaP NPs) were synthesized and used as the carrier of epirubicin (EPI) to enhance the efficacy of TACE therapy through autophagy inhibition. PAA/CaP NPs have a high loading capacity of EPI and a sensitive drug release behavior under acidic conditions. Moreover, PAA/CaP NPs block autophagy through the dramatic increase of intracellular Ca²⁺ content, which synergistically enhances the toxicity of EPI. TACE with EPI-loaded PAA/CaP NPs dispersed in lipiodol shows an obvious enhanced therapeutic outcome compared to the treatment with EPI-lipiodol emulsion in an orthotopic rabbit liver cancer model. This study not only develops a new delivery system for TACE but also provides a promising strategy targeting autophagy inhibition to improve the therapeutic effect of TACE for the HCC treatment.

Modulating Nanozyme-Based Nanomachines via Microenvironmental Feedback for Differential Photothermal Therapy of Orthotopic Gliomas

Gliomas are common and refractory primary tumors closely associated with the fine structures of the brain. Photothermal therapy (PTT) has recently shown promise as an effective treatment for gliomas. However, nonspecific accumulation of photothermal agents may affect adjacent normal brain structures, and the inflammatory response induced during PTT may result in an increased risk of brain tumor recurrence or metastasis. Here, the design and fabrication of an intelligent nanomachine is reported based on Gd₂ O₃ @Ir/TMB-RVG29 (G@IT-R) hybrid nanomaterials. These nanomaterials enable tumor-specific PTT and eliminate inflammation to protect normal brain tissue. The mechanism involves the rabies virus glycopeptide-29 peptide (RVG29) passing through the blood-brain barrier (BBB) and targeting gliomas. In the tumor microenvironment, Ir nanozymes can act as logic control systems to trigger chromogenic reaction amplification of 3,3',5,5'-tetramethylbenzidine (TMB) for tumor-specific PTT, whereas in normal brain tissues, they scavenge reactive oxygen species (ROS) generated by poor therapy and function as protective agents. Autophagy inhibition of Gd₂ O₃ enables excellent photothermal therapeutic effects on orthotopic gliomas and protection against inflammation in normal cells. The results of this study may prove useful in developing highly efficient nanomedicines for glioma treatment.

Efficient Immunotherapy of Drug-Free Layered Double Hydroxide Nanoparticles via Neutralizing Excess Acid and Blocking Tumor Cell Autophagy

Cancer immunotherapy efficacy is largely limited by the suppressive tumor immune microenvironment (TIME) where antitumor immune cells are inhibited and tumor antigens continue to mutate or be lost. To remodel the TIME, we here applied weakly alkaline layered double hydroxide nanoparticles (LDH NPs) to neutralize the excess acid and block autophagy of tumor cells for neoadjuvant cancer immunotherapy. Peritumoral injection of LDH NPs provided a long-term and efficient acid-neutralization in the TIME, blocked the lysosome-mediated autophagy pathway in tumor cells, and increased the levels of antitumor tumor-associated macrophages and T cells. These LDH NPs captured tumor antigens released in the tumor tissues and effectively inhibited the growth of both melanoma and colon tumors in vivo. These findings indicate that LDH NPs, as an immunomodulator and adjuvant, successfully "awaken" and promote the host innate and adaptive immune systems, showing promising potential for solid tumor immunotherapy.

Chemo-Phototherapy with Carfilzomib-Encapsulated TiN Nanoshells Suppressing Tumor Growth and Lymphatic Metastasis

The design of nanomedicine for cancer therapy, especially the treatment of tumor metastasis has received great attention. Proteasome inhibition is accepted as a new strategy for cancer therapy. Despite being a big breakthrough in multiple myeloma therapy, carfilzomib (CFZ), a second-in-class proteasome inhibitor is still unsatisfactory for solid tumor and metastasis therapy. In this study, hollow titanium nitride (TiN) nanoshells are synthesized as a drug carrier of CFZ. The TiN nanoshells have a high loading capacity of CFZ, and their intrinsic inhibitory effect on autophagy synergistically enhances the activity of CFZ. Due to an excellent photothermal conversion efficiency in the second near-infrared (NIR-II) region, TiN nanoshell-based photothermal therapy further induces a synergistic anticancer effect. In vivo study demonstrates that TiN nanoshells readily drain into the lymph nodes, which are responsible for tumor lymphatic metastasis. The CFZ-loaded TiN nanoshell-based chemo-photothermal therapy combined with surgery offers a remarkable therapeutic outcome in greatly inhibiting further metastatic spread of cancer cells. These findings suggest that TiN nanoshells act as an efficient carrier of CFZ for realizing enhanced outcomes for proteasome inhibitor-based cancer therapy, and this work also presents a "combined chemo-phototherapy assisted surgery" strategy, promising for future cancer treatment.

Perturbation of autophagy: An intrinsic toxicity mechanism of nanoparticles

Nanoparticles (NPs) have been widely used for various purposes due to their unique physicochemical properties. Such widespread applications greatly increase the possibility of human exposure to NPs in various ways. Once entering the human body, NPs may interfere with cellular homeostasis and thus affect the physiological system. As a result, it is necessary to evaluate the potential disturbance of NPs to multiple cell functions, including autophagy. Autophagy is an important cell function to maintain cellular homeostasis, and minimizing the disturbance caused by NP exposures to autophagy is critical to nanosafety. Herein, we summarized the recent research progress in nanotoxicity with particular focuses on the perturbation of NPs to cell autophagy. The basic processes of autophagy and complex relationships between autophagy and major human diseases were further discussed to emphasize the importance of keeping autophagy under control. Moreover, the most recent advances on perturbation of different types of NPs to autophagy were also reviewed. Last but not least, we also discussed major research challenges and potential coping strategies and proposed a safe-by-design strategy towards safer applications of NPs.

Recent advances in anti-multidrug resistance for nano-drug delivery system

Chemotherapy for tumors occasionally results in drug resistance, which is the major reason for the treatment failure. Higher drug doses could improve the therapeutic effect, but higher toxicity limits the further treatment. For overcoming drug resistance, functional nano-drug delivery system (NDDS) has been explored to sensitize the anticancer drugs and decrease its side effects, which are applied in combating multidrug resistance (MDR) via a variety of mechanisms including bypassing drug efflux, controlling drug release, and disturbing metabolism. This review starts with a brief report on the major MDR causes. Furthermore, we searched the papers from NDDS and introduced the recent advances in sensitizing the chemotherapeutic drugs against MDR tumors. Finally, we concluded that the NDDS was based on several mechanisms, and we looked forward to the future in this field.

Non-apoptotic cell death-based cancer therapy: Molecular mechanism, pharmacological modulators, and nanomedicine

As an emerging cancer therapeutic target, non-apoptotic cell death such as ferroptosis, necroptosis and pyroptosis, etc., has revealed significant potential in cancer treatment for bypassing apoptosis to enhance the undermined therapeutic efficacy triggered by apoptosis resistance. A variety of anticancer drugs, synthesized compounds and natural products have been proven recently to induce non-apoptotic cell death and exhibit excellent anti-tumor effects. Moreover, the convergence of nanotechnology with functional materials and biomedicine science has provided tremendous opportunities to construct non-apoptotic cell death-based nanomedicine for innovative cancer therapy. Nanocarriers are not only employed in targeted delivery of non-apoptotic inducers, but also used as therapeutic components to induce non-apoptotic cell death to achieve efficient tumor treatment. This review first introduces the main characteristics, the mechanism and various pharmacological modulators of different non-apoptotic cell death forms, including ferroptosis, necroptosis, pyroptosis, autophagy, paraptosis, lysosomal-dependent cell death, and oncosis. Second, we comprehensively review the latest progresses of nanomedicine that induces various forms of non-apoptotic cell death and focus on the nanomedicine targeting different pathways and components. Furthermore, the combination therapies of non-apoptotic cell death with photothermal therapy, photodynamic therapy, immunotherapy and other modalities are summarized. Finally, the challenges and future perspectives in this regard are also discussed.

Engineering Nanoplatform for Combined Cancer Therapeutics via Complementary Autophagy Inhibition

Despite advances in the development of tumor treatments, mortality from cancer continues to increase. Nanotechnology is expected to provide an innovative anti-cancer therapy, to combat challenges such as multidrug resistance and tumor recurrence. Nevertheless, tumors can greatly rely on autophagy as an alternative source for metabolites, and which desensitizes cancer cells to therapeutic stress, hindering the success of any current treatment paradigm. Autophagy is a conserved process by which cells turn over their own constituents to maintain cellular homeostasis. The multistep autophagic pathway provides potentially druggable targets to inhibit pro-survival autophagy under various therapeutic stimuli. In this review, we focus on autophagy inhibition based on functional nanoplatforms, which may be a potential strategy to increase therapeutic sensitivity in combinational cancer therapies, including chemotherapy, radiotherapy, phototherapy, sonodynamic therapy, and immunotherapy.

Inhibiting autophagy flux and DNA repair of tumor cells to boost radiotherapy of orthotopic glioblastoma

Radio-resistance of glioblastoma (GBM) remains a leading cause of radiotherapy failure because of the protective autophagy induced by X-Ray irradiation and tumor cells' strong capability of repairing damaged DNA. It is of great importance to overcome the radio-resistance for improving the efficacy of radiotherapy. Herein, we report the novel mechanism of core-shell copper selenide coated gold nanoparticles (Au@Cu_2-xSe NPs) inhibiting the protective autophagy and DNA repair of tumor cells to drastically boost the radiotherapy efficacy of glioblastoma. We reveal that the core-shell Au@Cu_2-xSe NPs can inhibit the autophagy flux by effectively alkalizing lysosomes. They can increase the SQSTM1/p62 protein levels of tumor cells without influencing their mRNA. We also reveal that Au@Cu_2-xSe NPs can increase the ubiquitination of DNA repair protein Rad51, and promote the degradation of Rad51 by proteasomes to prevent the DNA repair. The simultaneous inhibition of protective autophagy and DNA repair significantly suppress the growth of orthotopic GBM by using radiotherapy and our novel Au@Cu_2-xSe NPs. Our work provides a new insight and paradigm to significantly improve the efficacy of radiotherapy by rationally designing theranostic nano-agents to simultaneously inhibit protective autophagy and DNA repair of tumor cells.

Advances in smart delivery of food bioactive compounds using stimuli-responsive carriers: Responsive mechanism, contemporary challenges, and prospects

Many important food bioactive compounds are plant secondary metabolites that have traditional applications for health promotion and disease prevention. However, the chemical instability and poor bioavailability of these compounds represent major challenges to researchers. In the last decade, therefore, major impetus has been given for the research and development of advanced carrier systems for the delivery of natural bioactive molecules. Among them, stimuli-responsive carriers hold great promise for simultaneously improving stability, bioavailability, and more importantly delivery and on-demand release of intact bioactive phytochemicals to target sites in response to certain stimuli or combination of them (e.g., pH, temperature, oxidant, enzyme, and irradiation) that would eventually enhance therapeutic outcomes and reduce side effects. Hybrid formulations (e.g., inorganic-organic complexes) and multi-stimuli-responsive formulations have demonstrated great potential for future studies. Therefore, this review systematically compiles and assesses the recent advances on the smart delivery of food bioactive compounds, particularly quercetin, curcumin, and resveratrol through stimuli-responsive carriers, and critically reviews their functionality, underlying triggered-release mechanism, and therapeutic potential. Finally, major limitations, contemporary challenges, and possible solutions/future research directions are highlighted. Much more research is needed to optimize the processing parameters of existing formulations and to develop novel ones for lead food bioactive compounds to facilitate their food and nutraceutical applications.

A universal route with fine kinetic control to a family of penta-twinned gold nanocrystals

Some of the major difficulties hindering the synthesis of different types of colloidal nanocrystals are their complex synthetic methods and the lack of a universal growth mechanism in one system. Herein, we propose a general strategy of kinetically controlled seed-mediated growth to synthesize a family of penta-twinned gold nanocrystals. Specifically, different kinds of penta-twinned nanocrystals (truncated penta-twinned decahedra, truncated bipyramids, bipyramids, truncated bipyramids with tips, star-like penta-twinned nanocrystals, decahedra with concave edges, and decahedra) with tunable sizes and high purity were readily achieved in one system solely by tailoring the deposition kinetics of adatoms on different sites of decahedral seeds. The controllable deposition kinetics can be realized by changing the ratio of reductant/gold precursors (R), which dictates whether horizontal or vertical features along the 5-fold axis direction of Au decahedral seeds are produced. Additionally, the selective growth of a second metal (silver) on penta-twinned gold seeds can be reached through minor modification of R, which opens a new avenue for mechanistic investigation by visualizing the seed localization within the final particles. The present work demonstrates a general paradigm for the kinetic growth of penta-twinned crystals and would be extended to the synthesis of other families of nanocrystals.

We report the synthesis of linear ADPr oligomers of defined length up to a pentamer using an improved solid phase method. Binding study with human oncogenic helicase ALC1 shows that ADPr oligomers bind to ALC1 in a length-dependent manner.

The IL13α 2R paves the way for anti-glioma nanotherapy

Glioblastoma (GBM) is one of the most aggressive (grade IV) gliomas characterized by a high rate of recurrence, resistance to therapy and a grim survival prognosis. The long-awaited improvement in GBM patients' survival rates essentially depends on advances in the development of new therapeutic approaches. Recent preclinical studies show that nanoscale materials could greatly contribute to the improvement of diagnosis and management of brain cancers. In the current review, we will discuss how specific features of glioma pathobiology can be employed for designing efficient targeting approaches. Moreover, we will summarize the main evidence for the potential of the IL-13R alpha 2 receptor (IL13α2R) targeting in GBM early diagnosis and experimental therapy.

Combined effects of hyperthermia and chemotherapy on the regulate autophagy of oral squamous cell carcinoma cells under a hypoxic microenvironment

Autophagy has a complex dual role in tumor survival or cell death owning to that is an evolutionarily conserved catabolic mechanism and provides the cells with a sustainable source of biomolecules and energy for the maintenance of homeostasis under stressful conditions such as tumor microenvironment. Hyperthermia is a rapidly growing field in cancer therapy and many advances have been made in understanding and applying the mechanisms of hyperthermia. The shallow oral and maxillofacial position and its abundant blood supply are favorable for the use of hyperthermia. However, the relationship between hyperthermia and autophagy has not been examined of oral squamous cell carcinoma (OSCC) in the tumor hypoxia microenvironment. Here, the expression level of autophagy relative genes is examined to explore autophagy effect on the responses of hyperthermia, hypoxia, and innutrition tumor microenvironment. It is founded that hyperthermia and hypoxia cause autophagy in starvation conditions; further, in hypoxia and innutrition tumor microenvironment, hyperthermia combines YC-1 and 3-MA could inhibit HIF-1α/BNIP3/Beclin1 signal pathway and decrease the secretion of HMGB1; moreover, the cell apoptosis rate increases with an inhibited of cell migration capacity. Thus, the present study demonstrated that combined use of YC-1 and 3-MA might increase the death of tumor cells in physiological and hyperthermic conditions, which could be relevant with the inhibition of autophagy in OSCC tumor cells under hypoxia microenvironment in vitro, which offers new insight into the therapy of OSCC and its application in treating others study carcinomas.

Advances in autophagy as a target in the treatment of tumours

Autophagy is a multi-step lysosomal degradation process, which regulates energy and material metabolism and has been used to maintain homeostasis. Autophagy has been shown to be involved in the regulation of health and disease. But at present, there is no consensus on the relationship between autophagy and tumour, and we consider that it plays a dual role in the occurrence and development of tumour. That is to say, under certain conditions, it can inhibit the occurrence of tumour, but it can also promote the process of tumour. Therefore, autophagy could be used as a target for tumour treatment. The regulation of autophagy plays a synergistic role in the radiotherapy, chemotherapy, phototherapy and immunotherapy of tumour, and nano drug delivery system provides a promising strategy for improving the efficacy of autophagy regulation. This review summarised the progress in the regulatory pathways and factors of autophagy as well as nanoformulations as carriers for the delivery of autophagy modulators.

Protein-Mimicking Nanoparticles for a Cellular Regulation of Homeostasis

The distinct physical and chemical properties of nanoparticles (NPs) offer great opportunities to develop new strategies for diagnostic and therapeutic purposes. Whereas NPs often serve as inert nanocarriers, their inherent "biological" activities have recently been extensively unveiled and explored. These protein-mimicking NPs (dubbed protmins) have been reported to modulate a cellular homeostasis without displaying a general toxicity, which may act as potential nanomedicines to provide a monotherapy or combination therapy in a disease treatment. In the meanwhile, the unexpected behaviors of protmins in complex biological systems also raise new concerns on the biosafety issue. Herein, we summarize several categories of the protmin-based regulation of cellular homeostasis and discuss their broad effects on cell functions and behaviors.

Au nanobipyramids with Pt decoration enveloped in TiO2 nanoboxes for photocatalytic reactions

Noble metal nanocrystals and core-shell nanocomposites have attracted particular interest due to their unique optical properties originating from surface plasmon resonance (SPR) and wide applications related to the SPR effect. In this work, we designed and fabricated a new Au-Pt@TiO₂ nanocomposite, in which Au nanobipyramids (AuNBPs) decorated with platinum (Pt) clusters were enveloped in mesoporous TiO₂ nanoboxes with nanocavities. AuNBPs provide strong SPR absorption and localized field enhancement restricted to the cavities of TiO₂ nanoboxes. The Pt nanoclusters decorated on the surface of AuNBPs can effectively modulate the charge movement and energy transfer in the photocatalytic process. The enhanced electric field provides a local thermal effect for the photocatalytic reaction and promotes the injection process of hot electrons which facilitates carrier separation. The nanoboxes with nanocavities can effectively manage the usage of localized energy and provide space for reaction. Under the cooperative effects, the photocatalytic performance was remarkably improved along with durability and stability. For the AuNBP-Pt@TiO₂ nanoboxes, the rhodamine-B degradation efficiency was ∼6.5 times that of AuNBP@TiO₂ nanoboxes. The mechanism of the photocatalysis process was proposed based on experimental results and simulations. Benefiting from the excellent structure and properties, the obtained nanostructure is a promising candidate in the fields of pollutant degradation and chemical reaction catalysis.

The Role of the Ubiquitin Proteasome System in Glioma: Analysis Emphasizing the Main Molecular Players and Therapeutic Strategies Identified in Glioblastoma Multiforme

Gliomas constitute the most frequent tumors of the brain. High-grade gliomas are characterized by a poor prognosis caused by a set of attributes making treatment difficult, such as heterogeneity and cell infiltration. Additionally, there is a subgroup of glioma cells with properties similar to those of stem cells responsible for tumor recurrence after treatment. Since proteasomal degradation regulates multiple cellular processes, any mutation causing disturbances in the function or expression of its elements can lead to various disorders such as cancer. Several studies have focused on protein degradation modulation as a mechanism of glioma control. The ubiquitin proteasome system is the main mechanism of cellular proteolysis that regulates different events, intervening in pathological processes with exacerbating or suppressive effects on diseases. This review analyzes the role of proteasomal degradation in gliomas, emphasizing the elements of this system that modulate different cellular mechanisms in tumors and discussing the potential of distinct compounds controlling brain tumorigenesis through the proteasomal pathway.

Molecular Perspective of Nanoparticle Mediated Therapeutic Targeting in Breast Cancer: An Odyssey of Endoplasmic Reticulum Unfolded Protein Response (UPRER) and Beyond

Breast cancer (BC) is the second most frequent cause of death among women. Representing a complex and heterogeneous type of cancer, its occurrence is attributed by both genetic (gene mutations, e.g., BRCA1, BRCA2) and non-genetic (race, ethnicity, etc.) risk factors. The effectiveness of available treatment regimens (small molecules, cytotoxic agents, and inhibitors) decreased due to their poor penetration across biological barriers, limited targeting, and rapid body clearance along with their effect on normal resident cells of bone marrow, gastrointestinal tract, and hair follicles. This significantly reduced their clinical outcomes, which led to an unprecedented increase in the number of cases worldwide. Nanomedicine, a nano-formulation of therapeutics, emerged as a versatile delivering module for employment in achieving the effective and target specific delivery of pharmaceutical payloads. Adoption of nanotechnological approaches in delivering therapeutic molecules to target cells ensures not only reduced immune response and toxicity, but increases the stability of therapeutic entities in the systemic circulation that averts their degradation and as such increased extravasations and accumulation via enhanced permeation and the retention (EPR) effect in target tissues. Additionally, nanoparticle (NP)-induced ER stress, which enhances apoptosis and autophagy, has been utilized as a combative strategy in the treatment of cancerous cells. As nanoparticles-based avenues have been capitalized to achieve better efficacy of the new genera of therapeutics with enhanced specificity and safety, the present study is aimed at providing the fundamentals of BC, nanotechnological modules (organic, inorganic, and hybrid) employed in delivering different therapeutic molecules, and mechanistic insights of nano-ER stress induced apoptosis and autophagy with a perspective of exploring this avenue for use in the nano-toxicological studies. Furthermore, the current scenario of USA FDA approved nano-formulations and the future perspective of nanotechnological based interventions to overcome the existing challenges are also discussed.

An Updated Review on Implications of Autophagy and Apoptosis in Tumorigenesis: Possible Alterations in Autophagy through Engineered Nanomaterials and Their Importance in Cancer Therapy

Most commonly recognized as a catabolic pathway, autophagy is a perplexing mechanism through which a living cell can free itself of excess cytoplasmic components, i.e., organelles, by means of certain membranous vesicles or lysosomes filled with degrading enzymes. Upon exposure to external insult or internal stimuli, the cell might opt to activate such a pathway, through which it can gain control over the maintenance of intracellular components and thus sustain homeostasis by intercepting the formation of unnecessary structures or eliminating the already present dysfunctional or inutile organelles. Despite such appropriateness, autophagy might also be considered a frailty for the cell, as it has been said to have a rather complicated role in tumorigenesis. A merit in the early stages of tumor formation, autophagy appears to be salutary because of its tumor-suppressing effects. In fact, several investigations on tumorigenesis have reported diminished levels of autophagic activity in tumor cells, which might result in transition to malignancy. On the contrary, autophagy has been suggested to be a seemingly favorable mechanism to progressed malignancies, as it contributes to survival of such cells. Based on the recent literature, this mechanism might also be activated upon the entry of engineered nanomaterials inside a cell, supposedly protecting the host from foreign materials. Accordingly, there is a good chance that therapeutic interventions for modulating autophagy in malignant cells using nanoparticles may sensitize cancerous cells to certain treatment modalities, e.g., radiotherapy. In this review, we will discuss the signaling pathways involved in autophagy and the significance of the mechanism itself in apoptosis and tumorigenesis while shedding light on possible alterations in autophagy through engineered nanomaterials and their potential therapeutic applications in cancer. SIGNIFICANCE STATEMENT: Autophagy has been said to have a complicated role in tumorigenesis. In the early stages of tumor formation, autophagy appears to be salutary because of its tumor-suppressing effects. On the contrary, autophagy has been suggested to be a favorable mechanism to progressed malignancies. This mechanism might be affected upon the entry of nanomaterials inside a cell. Accordingly, therapeutic interventions for modulating autophagy using nanoparticles may sensitize cancerous cells to certain therapies.

Metaoptronic Multiplexed Interface for Probing Bioentity Behaviors

Biointerface sensors have brought about remarkable advances in modern biomedicine. To accurately monitor bioentity's behaviors, biointerface sensors need to capture three main types of information, which are the electric, spectroscopic, and morphologic signals. Simultaneously obtaining these three types of information is of critical importance in the development of future biosensor, which is still not possible in the existing biosensors. Herein, by synergizing metamaterials, optical, and electronic sensing designs, we proposed the metaoptronic multiplexed interface (MMI) and built a MMI biosensor which can collectively record electric, spectroscopic, and morphologic information on bioentities. The MMI biosensor enables the real-time triple-monitoring of cellular dynamics and opens up the possibility for powerlessly monitoring ocular dryness. Our findings not only demonstrate an advanced multiplexed biointerface sensor with integrated capacities but also help to identify a uniquely significant arena for the nanomaterials, meta-optics, and nanotechnologies to play their roles in a complementary manner.

Chemosensitivity enhanced by autophagy inhibition based on a polycationic nano-drug carrier

In recent years, with the increasing understanding of the role of autophagy in tumorigenesis and development, a steady stream of studies have demonstrated that both excessive induction and inhibition of autophagy could effectively improve the therapeutic efficacy against tumors during cytotoxic or molecularly targeted drug therapy. Among them, autophagy inhibition mediated by nanomaterials has become an appealing notion in nanomedicine therapeutics, since it can be exploited as an effective adjuvant in chemotherapy or as a potential anti-tumor agent. Herein, we constructed a pH-sensitive nanoplatform loaded with epirubicin (EPI) (mPEG-b-P(DPA-b-DMAEMA)/EPI), enabling effective autophagy inhibition in the process of tumor-targeting therapy and further sensitized the tumors to EPI. It was found that polycationic nanomicelles (PEDD-Ms) displayed specific localization in lysosomes after entering tumor cells and caused the impairment of lysosomal degradation capacity through lysosomal alkalization in a dose-dependent manner. HepG2 cells treated with PEDD-Ms displayed a large-scale accumulation of autophagosomes and LC3 (an autophagosome marker protein), and the degradation of the autophagy substrate p62 was also blocked, which indicated that these functional nanomicelles could significantly inhibit autophagy. Meanwhile, the typical morphological characteristics of autophagosomes were directly visualized by TEM. In vivo results also showed that the tumor-targeted and autophagy inhibition-associated nanoplatform therapy could effectively improve the therapeutic efficiency of EPI, which may be partially attributed to the fact that autophagy inhibition could enhance the sensitivity of tumor cells to EPI. Overall, we revealed the effect of polycationic nanomicelles on autophagic processes in tumor cells and explored their possible molecular mechanism, also considering the synergistic outcome between autophagy mediated by nanomaterials and chemotherapeutic drugs to improve the therapeutic effect on tumors.

Cobalt oxide nanoparticle-synergized protein degradation and phototherapy for enhanced anticancer therapeutics

How to enable protein degradation pathways including the autophagy-lysosome pathway (ALP) and the ubiquitin-proteasome system (UPS) to enhance the efficacy of anticancer treatments remains a substantial challenge. Cobalt oxide nanoparticles (Co₃O₄ NPs) have attracted interest in recent years for their potential use as a synergistic anticancer treatment, although their therapeutic mechanisms of action are still poorly understood. Here, we describe the synergistic use of Co₃O₄ NPs as an autophagy inhibitor, chemosensitizer and photosensitizer, which manipulate protein degradation pathways (ALP and UPS) and photothermal therapy for enhanced anticancer treatments both in vitro and in vivo. We show that Co₃O₄ NPs can induce autolysosome accumulation and lysosomal functions damage by inhibiting lysosomal proteolytic activity and reducing intracellular ATP levels. Notably, Co₃O₄ NPs can be combined with the proteasome inhibitor, Carfilzomib (Cfz), to promote the accumulation of autophagic substrates, protein ubiquitination, and endoplasmic reticulum stress, and in doing so, inhibit cancer progression. By taking advantage of their photothermal conversion efficiency, Co₃O₄ NPs can also serve as photothermal sensitizer, which synergistically enhances the anticancer efficacy of Cfz both in vitro and in vivo. In summary, we provide evidence of a nanomaterial-synergized, photothermal anticancer strategy that synergistically targets cancer cell survival pathways and may eventually serve to enhance the anticancer efficacy of established cancer therapeutics.

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field.

TiO2 nanoparticles enhance the chemotherapeutic effects of 5-fluorouracil in human AGS gastric cancer cells via autophagy blockade

AIMS

Nanoparticles (NPs)-based drugs have been recently introduced to improve the efficacy of current therapeutic strategies for the treatment of cancer; however, the molecular mechanisms by which a NP interacts with cellular systems still need to be delineated. Here, we utilize the autophagic potential of TiO2 NPs for improving chemotherapeutic effects of 5-fluorouracil (5-FU) in human AGS gastric cells.

MATERIALS AND METHODS

Cell growth and viability were determined by trypan blue exclusion test and MTT assay, respectively. Vesicular organelles formation was evaluated by acridine orange staining of cells. Cell cycle and apoptosis were monitored by flow cytometry. Reactive oxygen species (ROS) level were measured by DCHF-DA staining. Autophagy was examined by q-PCR and western blotting. Molecular docking was used for studying NP interaction with autophagic proteins.

KEY FINDINGS

TiO2 NPs increase ROS production, impair lysosomal function and subsequently block autophagy flux in AGS cells. In addition, the autophagy blockade induced by non-toxic concentrations of TiO2 NPs (1 μg/ml) can promote cytotoxic and apoptotic effects of 5-FU in AGS cells.

SIGNIFICANCE

These results confirm the beneficial effects of TiO2 NPs in combination with chemotherapy in in vitro model of gastric cancer, which may pave the way to develop a possible solution to circumvent chemoresistance in cancer.

Augmenting Tumor-Starvation Therapy by Cancer Cell Autophagy Inhibition

It was recently recognized that cancer therapeutic efficacy may be greatly compromised by an intrinsic protective mechanism called autophagy, by which cancer cells survive in harsh conditions such as starvation. Here, a synergetic strategy is described for cancer treatment by suppressing such a protective mechanism for augmenting tumor-starvation therapy. The synergetic therapy is achieved by restraining glucose metabolism using an antiglycolytic agent to predispose cancer cells to severe energy deprivation; concurrently the downstream autophagic flux and compensatory energy supplies are blocked by the autophagy inhibitor black phosphorus nanosheet. Cancer cells fail to extract their own nutrient to feed themselves, finally succumbing to therapeutic interventions and starving to death. Both in vitro and in vivo results evidence the cooperative effect between the autophagy inhibitor and antiglycolytic agent, which leads to remarkable synergetic antineoplastic outcome. It is expected that such a combinational approach by concurrently blocking exogenous and endogenous nutrition supplies will be beneficial to the design of effective tumor-specific cancer therapies in the future.

Silver nanoparticles regulate autophagy through lysosome injury and cell hypoxia in prostate cancer cells

With the rapid development of nanotechnology, nanomaterials are now being used for cancer treatment. Although studies on the application of silver nanoparticles in cancer treatment are burgeoning, few studies have investigated the toxicology mechanisms of autophagy in cancer cells under exposure to sublethal silver nanoparticles. Here, we clarified the distinct mechanisms of silver nanoparticles for the regulation of autophagy in prostate cancer PC-3 cells under sublethal exposure. Silver nanoparticle treatment caused lysosome injury, including the decline of lysosomal membrane integrity, decrease of lysosomal quantity, and attenuation of lysosomal protease activity, which resulted in blockage of autophagic flux. In addition, sublethal silver nanoparticle exposure activated AMP-activated protein kinase/mammalian target of rapamycin-dependent signaling pathway to modulate autophagy, which resulted from silver nanoparticles-induced cell hypoxia and energy deficiency. Taken together, the results show that silver nanoparticles could regulate autophagy via lysosome injury and cell hypoxia in PC-3 cells under sublethal dose exposure. This study will provide an experimental basis for the cancer therapy of nanomaterials.

Gallbladder Cancer Progression Is Reversed by Nanomaterial-Induced Photothermal Therapy in Combination with Chemotherapy and Autophagy Inhibition

Introduction

Gallbladder cancer (GBC) is the most common malignancy in biliary tract with extremely poor prognosis. Photothermal therapy (PTT) shows great promises for tumor therapy, which causes tumor cell death via selectively directed heating released by nanoparticles under the near-infrared irradiation. Through degrading damaged organelles and misfolded proteins in autophagosomes, autophagy plays a vital role in maintaining the intracellular homeostasis. The present study attempted to combine chemotherapy and autophagy blocking with PTT.

Materials and Methods

We purchased multi-walled carbon nanotubes from Nanostructured and Amorphous Materials and performed PTT using an 808-nm diode laser. The cytotoxic effects of PTT and chemotherapy in vitro were assessed by cell viability analysis. The effects of PTT and chemotherapy on autophagy in vitro were assessed by GFP-LC3 and Western blot. And these results were confirmed by in vivo experiment.

Results

Both PTT and chemotherapy could trigger cytoprotective autophagy to tolerate the cellular stresses and prolong the survival of GBC cell; therefore, the blocking of autophagy could enhance the efficacy of PTT and chemotherapy in GBC treatment in vitro and in vivo.

Conclusion

Chemotherapeutic drug doxorubicin and autophagy inhibitor chloroquine could enhance the efficacy of nanoparticle-mediated hyperthermia in GBC.

Realization of red plasmon shifts by the selective etching of Ag nanorods

The red plasmon shifts is realized through selective deposition of Au atoms and etching of Ag atoms on the Ag nanorods.

Pro-Death or Pro-Survival: Contrasting Paradigms on Nanomaterial-Induced Autophagy and Exploitations for Cancer Therapy

Autophagy is a critical lysosome-mediated cellular degradation process for the clearance of damaged organelles, obsolete proteins, and invading pathogens and plays important roles in the pathogenesis and treatment of human diseases including cancer. While not a cell death process per se, autophagy is nevertheless intimately linked to a cell's live/die decision. Basal autophagy, operating constitutively at low levels in essentially every mammalian cell, is vital for maintaining cellular homeostasis and promotes cell survival. On the other hand, elevated level of autophagy is frequently observed in cells responding to a physical, chemical, or biological stress. This "induced" autophagy, a hallmark under a variety of pathological and pathophysiological conditions, may be either pro-death or pro-survival, two contrasting paradigms for cell fate determination. Research in our laboratory and other groups around the world over the last 15 years has revealed nanomaterials as a unique class of autophagy inducers, with the capability of elevating the cellular autophagy to extremely high levels. In this Account we focus on the contrasting cell fate decision impacted by nanomaterial-induced autophagy. First, we give a brief introduction to nanomaterial-induced autophagy and summarize our current understanding on how it affects a cell's live/die decision. Autophagy induced by nanomaterials, in most cases, promotes cell death, but a significant number of nanomaterials are also able to elicit pro-survival autophagy. Although not a common feature, some nanomaterials may induce pro-death autophagy in one cell type while eliciting pro-survival autophagy in a different cell type. The ability to control the level of the induced autophagy, and furthermore its pro-death/pro-survival nature, is critically important for nanomedicine. Second, we discuss several possible mechanistic insights on the pro-death/pro-survival decision for nanomaterial-induced autophagy. "Disrupted" autophagic processes, with a "block" or perhaps "diversion" at the various stages, may be a characteristic hallmark for nanomaterial-induced autophagy, rendering it intrinsically pro-death in nature. On the other hand, autophagy-mediated upregulation and activation of pro-survival factors or signaling pathways, overriding the intrinsic pro-death nature, may be a common mechanism for nanomaterial-induced pro-survival autophagy. In addition, cargo degradation and reactive oxygen species may also play important roles in the pro-death/pro-survival decision impacted by nanomaterial-induced autophagy. Finally, we focus on the situation where nanomaterials induce autophagy in cancer cells and summarize the different strategies in exploiting the pro-death or pro-survival nature of nanomaterial-induced autophagy to enhance the various modalities of cancer therapy, including direct cancer cell killing, chemotherapy and radiotherapy, photothermal therapy, and integrated diagnosis and therapy. While the details vary, the basic principle is simple and straightforward. If the induced autophagy is pro-death, maximize it. Otherwise, inhibit it. Effective exploitation of nanomaterial-induced autophagy has the potential to become a new weapon in our ever-increasing arsenal to fight cancer, particularly difficult-to-treat and drug-resistant cancer.

Antiangiogenesis-Combined Photothermal Therapy in the Second Near-Infrared Window at Laser Powers Below the Skin Tolerance Threshold

Photothermal agents with strong light absorption in the second near-infrared (NIR-II) region (1000-1350 nm) are strongly desired for successful photothermal therapy (PTT). In this work, titania-coated Au nanobipyramids (NBP@TiO₂) with a strong plasmon resonance in the NIR-II window were synthesized. The NBP@TiO₂ nanostructures have a high photothermal conversion efficiency of (93.3 ± 5.2)% under 1064-nm laser irradiation. They are also capable for loading an anticancer drug combretastatin A-4 phosphate (CA4P). In vitro PTT studies reveal that 1064-nm laser irradiation can efficiently ablate human lung cancer A549 cells and enhance the anticancer effect of CA4P. Moreover, the CA4P-loaded NBP@TiO₂ nanostructures combined with PTT induce a synergistic antiangiogenesis effect. In vivo studies show that such CA4P-loaded NBP@TiO₂ nanostructures under mild 1064-nm laser irradiation at an optical power density of 0.4 W cm^-2, which is lower than the skin tolerance threshold value, exhibit a superior antitumor effect. This work presents not only the development of the NBP@TiO₂ nanostructures as a novel photothermal agent responsive in the NIR-II window but also a unique combined chemo-photothermal therapy strategy for cancer therapy.

Cancer Cell Membrane-Biomimetic Nanoplatform for Enhanced Sonodynamic Therapy on Breast Cancer via Autophagy Regulation Strategy

Autophagy was considered as a double-edged sword that might cooperate, aggravate, or antagonize apoptosis. We found that the sonodynamic therapy (SDT) in low dosage induced autophagy and might function as a survival pathway for breast cancer and exhibit resistance to SDT-mediated apoptosis. In this sense, it was highly desired to enhance SDT via autophagy regulation strategy. Herein, we reported a biomimetic nanoplatform based on hollow mesoporous titanium dioxide nanoparticles (HMTNPs) by autophagy inhibitor (hydroxychloroquine sulphate, HCQ) loading and cancer cell membrane (CCM) coating. Owing to the biomimetic surface functionalization, the CCM-HMTNPs/HCQ could escape from macrophage phagocytosis, actively recognize and home in on the tumor by homologous targeting ability. Afterward, the released HCQ in response to the ultrasound stimulus was capable of blocking the autophagic flux and cutting off the nutrients supply derived from the damaged organelles, which was anticipated to abrogate the cells' resistance to SDT. Meanwhile, the vessel normalization effect of HCQ alleviated the tumor hypoxia, which was bound to enhance the oxygen-dependent HMTNPs-mediated SDT treatment. Based on the above findings, it was undoubtedly logical that CCM-HMTNPs/HCQ would sensitize breast cancer cells to SDT via autophagy regulation strategy, which held a great promise in cancer treatment.

Gold Nanobipyramids: An Emerging and Versatile Type of Plasmonic Nanoparticles

Gold nanobipyramids (Au NBPs) and gold nanorods (Au NRs) are two types of elongated plasmonic nanoparticles with their longitudinal dipolar plasmon wavelengths synthetically tunable from the visible region to the near-infrared region. Both have highly polarization-dependent absorption and scattering cross sections because of their anisotropic geometries. In terms of their differences, each Au NBP has five equally angularly separated twinning planes that are aligned parallel to the length direction, while the most common Au NRs are single-crystalline. As a result, Au NBPs possess two sharp end tips, while Au NRs have rounded or flat ends, resulting in very different plasmonic properties. In general, Au NBPs exhibit larger local electric field enhancements, larger optical cross sections, narrower line widths, better shape and size uniformity, and higher refractive index sensitivity than Au NRs. With the recent development of reliable methods for the growth of Au NBPs with high purity and uniformity, Au NBPs have been attracting much interest for the investigation of their intriguing plasmonic properties and applications. In this Account, we provide a concise introduction to Au NBPs, including their fascinating plasmonic properties, wet-chemistry growth methods, plasmonic applications, and structure-directing function. The synthesis of uniform Au NBPs with variable sizes is of vital importance to control their plasmonic properties. In the synthesis part, we summarize the recent developments on the synthesis of Au NBPs, with a focus on the role of seeds in the seed-mediated growth of pentatwinned Au NBPs and methods to improve their number purity. The excellent plasmonic properties of Au NBPs make them promising candidates for numerous applications. To further explore the largely improved functionalities of Au NBPs, different types of Au-NBP-based hybrid nanostructures have been prepared. They exhibit synergistic interactions between Au NBPs and the other components. We highlight the widespread plasmonic applications of Au NBPs and Au-NBP-based hybrid nanostructures in the fields of spectroscopy, photocatalysis, sensing, switching, and biomedical technologies. We next turn to the structure-directing function of Au NBPs to demonstrate the Au-NBP-directed growth of metal nanostructures and their applications. The structure-directing function is enabled by the unique pentatwinned crystalline structure of Au NBPs. Finally, we conclude with remarks on the future perspectives and research directions on Au NBPs as well as the remaining challenges. We hope that this Account will act as a platform to offer fascinating opportunities and stimulate fast-growing research on the various aspects of Au NBPs.

Key Role of Microtubule and Its Acetylation in a Zinc Oxide Nanoparticle-Mediated Lysosome-Autophagy System

Autophagy is a biological process that has attracted considerable attention as a target for novel therapeutics. Recently, nanomaterials (NMs) have been reported to modulate autophagy, which makes them potential agents for the treatment of autophagy-related diseases. In this study, zinc oxide nanoparticles (ZNPs) are utilized to evaluate NM-induced autophagy and debate the mechanisms involved. It is found that ZNPs undergo pH-dependent ion shedding and that intracellular zinc ions (Zn²⁺ ) play a crucial role in autophagy. Autophagy is activated with ZNPs treatment, which is inhibited after Zn²⁺ sequestration via ethylenediamine tetra-acetic acid. Lysosome-based autophagic degradation is halted after ZNPs treatment for more than 3 h and is accompanied by blockage of lysophagy, which renews impaired lysosomes. Furthermore, the microtubule (MT) system participates in ZNP-induced lysosome-autophagy system changes, especially in the fusion between autophagosomes and lysosomes. MT acetylation is helpful for protecting from ZNP-induced MT disruption, and it promotes the autophagic degradation process. In conclusion, this study provides valuable information on NM-induced lysosome-autophagy system changes, particularly with respect to the role of lysophagy and the MT system, which point to some attractive targets for the design of engineered nanoparticles.

Autophagy as a molecular target for cancer treatment

Autophagy is an evolutionarily conserved catabolic mechanism, by which eukaryotic cells recycle or degrades internal constituents through membrane-trafficking pathway. Thus, autophagy provides the cells with a sustainable source of biomolecules and energy for the maintenance of homeostasis under stressful conditions such as tumor microenvironment. Recent findings revealed a close relationship between autophagy and malignant transformation. However, due to the complex dual role of autophagy in tumor survival or cell death, efforts to develop efficient treatment strategies targeting the autophagy/cancer relation have largely been unsuccessful. Here we review the two-faced role of autophagy in cancer as a tumor suppressor or as a pro-oncogenic mechanism. In this sense, we also review the shared regulatory pathways that play a role in autophagy and malignant transformation. Finally, anti-cancer therapeutic agents used as either inhibitors or inducers of autophagy have been discussed.

Au Nanobottles with Synthetically Tunable Overall and Opening Sizes for Chemo-Photothermal Combined Therapy

Highly asymmetric Au nanostructures, such as split Au nanorings and Au nanocups, exhibit attractive plasmonic properties because of their asymmetric geometries. To facilitate their plasmonic applications, effective and facile synthetic methods for producing asymmetric Au nanostructures with controllable sizes and uniform shapes are highly desirable. Herein, we report on an approach for the synthesis of largely asymmetric colloidal Au nanobottles with synthetically tunable overall and opening sizes. Au nanobottles with overall sizes in the range of ∼100-230 nm are obtained through sacrificial templating with differently sized PbS nano-octahedra. The opening sizes of the produced Au nanobottles can be tailored from ∼10 to ∼120 nm by either adjusting the Au/PbS molar ratio in the growth process or controlling the oxidation degree. The achieved size tunability allows the plasmon resonance wavelength of Au nanobottles to be varied in the range of ∼600-900 nm. Our uniform Au nanobottles, which possess controllable sizes, large cavity volumes, and tunable plasmon resonance wavelengths in the visible to near-infrared range, have been further applied for anticancer drug delivery and photothermal therapy. The effects of surface coating and the opening size of Au nanobottles on the drug encapsulation efficiency (EE) and initial burst drug release are systemically evaluated. A high doxorubicin EE and low initial burst drug release are realized with the dense silica-coated Au nanobottles having an opening size of 44 nm. In addition, chemo-photothermal combined therapy has been demonstrated with the doxorubicin-loaded Au nanobottles. Our results will be helpful for the design of Au nanobottles with different sizes and plasmonic properties as well as provide ample opportunities for exploring various plasmon-enabled applications of Au nanobottles.

Titania-coated 2D gold nanoplates as nanoagents for synergistic photothermal/sonodynamic therapy in the second near-infrared window

The development of efficient nanomedicines to improve anticancer therapeutic effects is highly attractive. In this work, we firstly report titania-coated Au nanoplate (Au NPL@TiO2) heterostructures, which play dual roles as nanoagents for synergistic photothermal/sonodynamic therapy in the second near-infrared (NIR) window. On the one hand, because the controlled TiO2 shells endow the Au NPL@TiO2 nanostructures with a red shift to the NIR II region, the as-prepared Au NPL@TiO2 nanostructures possess a high photothermal conversion efficiency of 42.05% when irradiated by a 1064 nm laser and are anticipated to be very promising candidates as photothermal agents. On the other hand, the Au nanoplates (Au NPLs), as electron traps, vastly improve the generation of reactive oxygen species (ROS) by the Au NPL@TiO2 nanostructures in contrast with pure TiO2 shell nanoparticles upon activation by ultrasound (US) via a sonodynamic process. Moreover, the toxicity and therapeutic effect of the Au NPL@TiO2 nanostructures were relatively systemically evaluated in vitro. The Au NPL@TiO2 nanostructures generate a large amount of intracellular ROS and exhibit laser power density-dependent toxicity, which eventually induces apoptosis of cancer cells. Furthermore, a synergistic therapeutic effect, with a cell viability of only 20.3% upon both photothermal and sonodynamic activation, was achieved at low concentrations of the Au NPL@TiO2 nanostructures. Experiments on mice also demonstrate the superiority of the combination of PTT and SDT, with the total elimination of tumors. This work provides a way of applying two-dimensional (2D) gold nanoplate core/TiO2 shell nanostructures as novel nanoagents for advanced multifunctional anticancer therapies in the second NIR window.

Targeting mitochondria with Au–Ag@Polydopamine nanoparticles for papillary thyroid cancer therapy

A mitochondria-targeted and exocytosis inhibition strategy of polydopamine-coated inorganic nanoparticles for enhanced papillary thyroid cancer therapy is demonstrated.