Blocking Autophagic Flux Enhances Iron Oxide Nanoparticle Photothermal Therapeutic Efficiency in Cancer Treatment

Carbohydrate polymer-functionalized metal nanoparticles in cancer therapy: A review

Metal nanoparticles have been emerged as promising candidates in cancer therapy because of their large surface area, optical properties and ROS generation. Therefore, these nanoparticles are able to mediate cell death through hyperthermia, photothermal therapy and ROS-triggered apoptosis. The various metal nanoparticles including gold, silver and iron oxide nanostructures have been exploited for the theranostic application. Moreover, precision oncology and off-targeting features can be improved by metal nanoparticles. The modification of metal nanoparticles with carbohydrate polymers including chitosan, hyaluronic acid, cellulose, agarose, starch and pectin, among others can significantly improve their anti-cancer activities. Carbohydrate polymers have been idea for the purpose of drug delivery due to their biocompatibility, biodegradability and increasing nanoparticle stability. In addition, carbohydrate polymers are able to improve drug delivery, cellular uptake and sustained release of cargo. Such nanoparticles are capable of responding to the specific stimuli in the tumor microenvironment including pH and light. Furthermore, the carbohydrate polymer-modified metal nanoparticles can be utilized for the combination of chemotherapy, phototherapy and immunotherapy. Since the biocompatibility and long-term safety are critical factors for the clinical translation of nanoparticles, the modification of metal nanoparticles with carbohydrate polymers can improve this way to the application in clinic.

Hyperthermia/glutathione-triggered ferritin nanoparticles amplify the ferroptosis for synergistic tumor therapy

Breast cancer is the most diagnosed malignancy in women globally, and drug resistance is among the major obstacles to effective breast cancer treatment. Emerging evidence indicates that photothermal therapy and ferroptosis are both promising therapeutic techniques for the treatment of drug-resistant breast tumors. In this study, we proposed a thermal/ferroptosis/magnetic resonance imaging (MRI) triple functional nanoparticle (I@P-ss-FRT) in which ferritin, an iron storage material with excellent cellular uptake capacity, was attached via disulfide bonds onto polydopamine coated iron oxide nanoparticle (I@P) as photothermal transduction agent and MRI probe. I@P-ss-FRT converted the near-infrared light (NIR) into localized heat which accelerated the release of ferrous ions from ferritin accomplished by glutathione reduction and subsequently induced ferroptosis. The drug-resistant cancer cell lines exhibited a more significant uptake of I@P-ss-FRT and sensitivity to PTT/ferroptosis compared with normal cancer cell lines. In vivo, I@P-ss-FRT plus NIR displayed the best tumor-killing potential with inhibitory rate of 83.46 %, along with a decline in GSH/GPX-4 content and an increase in lipid peroxides generation at tumor sites. Therefore, I@P-ss-FRT can be applied to combat drug-resistant breast cancer.

Tailor-Made Autophagy Cascade Amplification Polymeric Nanoparticles for Enhanced Tumor Immunotherapy

Chemotherapeutics can induce immunogenic cell death (ICD) by triggering autophagy and mediate antitumor immunotherapy. However, using chemotherapeutics alone can only cause mild cell-protective autophagy and be incapable of inducing sufficient ICD efficacy. The participation of autophagy inducer is competent to enhance autophagy, so the level of ICD is promoted and the effect of antitumor immunotherapy is highly increased. Herein, tailor-made autophagy cascade amplification polymeric nanoparticles STF@AHPPE are constructed to enhance tumor immunotherapy. Arginine (Arg), polyethyleneglycol-polycaprolactone, and epirubicin (EPI) are grafted onto hyaluronic acid (HA) via disulfide bond to form the AHPPE nanoparticles and autophagy inducer STF-62247 (STF) is loaded. When STF@AHPPE nanoparticles target to tumor tissues and efficiently enter into tumor cells with the help of HA and Arg, the high glutathione concentration leads to the cleavage of disulfide bond and the release of EPI and STF. Finally, STF@AHPPE induces violent cytotoxic autophagy and strong ICD efficacy. As compared to AHPPE nanoparticles, STF@AHPPE nanoparticles kill the most tumor cells and show the more obvious ICD efficacy and immune activation ability. This work provides a novel strategy for combining tumor chemo-immunotherapy with autophagy induction.

Nanomedicine for autophagy modulation in cancer therapy: a clinical perspective

In recent years, progress in nanotechnology provided new tools to treat cancer more effectively. Advances in biomaterials tailored for drug delivery have the potential to overcome the limited selectivity and side effects frequently associated with traditional therapeutic agents. While autophagy is pivotal in determining cell fate and adaptation to different challenges, and despite the fact that it is frequently dysregulated in cancer, antitumor therapeutic strategies leveraging on or targeting this process are scarce. This is due to many reasons, including the very contextual effects of autophagy in cancer, low bioavailability and non-targeted delivery of existing autophagy modulatory compounds. Conjugating the versatile characteristics of nanoparticles with autophagy modulators may render these drugs safer and more effective for cancer treatment. Here, we review current standing questions on the biology of autophagy in tumor progression, and precursory studies and the state-of-the-art in harnessing nanomaterials science to enhance the specificity and therapeutic potential of autophagy modulators.

Autophagy modulation in breast cancer utilizing nanomaterials and nanoparticles

Autophagy regenerates cellular nutrients, recycles metabolites, and maintains hemostasis through multistep signaling pathways, in conjunction with lysosomal degradation mechanisms. In tumor cells, autophagy has been shown to play a dual role as both tumor suppressor and tumor promoter, leading to the discovery of new therapeutic strategies for cancer. Therefore, regulation of autophagy is essential during cancer progression. In this regard, the use of nanoparticles (NPs) is a promising technique in the clinic to modulate autophagy pathways. Here, we summarized the importance of breast cancer worldwide, and we discussed its classification, current treatment strategies, and the strengths and weaknesses of available treatments. We have also described the application of NPs and nanocarriers (NCs) in breast cancer treatment and their capability to modulate autophagy. Then the advantages and disadvantaged of NPs in cancer therapy along with future applications will be disscussed. The purpose of this review is to provide up-to-date information on NPs used in breast cancer treatment and their impacts on autophagy pathways for researchers.

Photothermal therapy (PTT) is an effective treatment measure against solid tumors which fails to respond conventional chemo/radiation therapies in clinic

Photothermal therapy (PTT) has emerged as a fast, precisive, and cost-effective anticancer therapy protocol. Here we applied our previously designed nanomaterial (Tocophotoxil) for prospective PTT application to manage radiation- and chemo-resistant cancers in a preclinical model. A PTT dose vs. efficacy relationship was established for radioresistant breast (ZR-75-1 50Gy, 4T1 20Gy) and chemo-resistant ovarian (A2780LR) cancer cells and tumors in mice models. Compared to the sensitive cases, resistant cells treated with PTT for a shorter duration show higher endurance. However, preclinical tumor xenografts treated with optimal PTT dose show 2-3 fold higher longevity (P ≤ 0.05) of treated mice monitored by non-invasive imaging methods. Elevated ERK and AKT activation in radioresistant or only AKT activation in chemo-resistant cells were contributory to higher cell survival in sub-optimal PTT dose. A comprehensive single-cell Raman map of PTT treated ZR-75-1 cell reveals broad-spectrum macromolecular deformities, including protein damage features. Marked induction of pJNK, unfolded protein response (UPR) pathway, increased reactive oxygen species (ROS), and lipid peroxidation in PTT-treated cells disrupted the intracellular homeostasis. Analyzing cellular ultrastructure, the coexistence of swollen endoplasmic reticulum, and autophagic bodies after PTT indicate possible coordination between UPR and autophagy pathways. Therefore, this comprehensive study provides new evidence on the potential impact of PTT as a standalone therapy for ablation of failed conventional therapy-resistant cancers in vivo, the success of which is intricately linked to the PTT dose optimization. The study, for the first time, also illustrates that under PTT treatment, concerted action of novel molecular switches such as JNK activation and UPR activation plays a vital role in triggering autophagy and cancer cell death.

Nanotherapeutics in autophagy: a paradigm shift in cancer treatment

Autophagy is a catabolic process in which an organism responds to its nutrient or metabolic emergencies. It involves the degradation of cytoplasmic proteins and organelles by forming double-membrane vesicles called "autophagosomes." They sequester cargoes, leading them to degradation in the lysosomes. Although autophagy acts as a protective mechanism for maintaining homeostasis through cellular recycling, it is ostensibly a cause of certain cancers, but a cure for others. In other words, insufficient autophagy, due to genetic or cellular dysfunctions, can lead to tumorigenesis. However, many autophagy modulators are developed for cancer therapy. Diverse nanoparticles have been documented to induce autophagy. Also, the highly stable nanoparticles show blockage to autophagic flux. In this review, we revealed a general mechanism by which autophagy can be induced or blocked via nanoparticles as well as several studies recently performed to prove the stated fact. In addition, we have also elucidated the paradoxical roles of autophagy in cancer and how their differential role at different stages of various cancers can affect its treatment outcomes. And finally, we summarize the breakthroughs in cancer disease treatments by using metallic, polymeric, and liposomal nanoparticles as potent autophagy modulators.

Puzzling Out Iron Complications in Cancer Drug Resistance

Iron metabolism are frequently disrupted in cancer. Patients with cancer are prone to anemia and receive transfusions frequently; the condition which results in iron overload, contributing to serious therapeutic complications. Iron is introduced as a carcinogen that may increase tumor growth. However, investigations regarding its impact on response to chemotherapy, particularly the induction of drug resistance are still limited. Here, iron contribution to cell signaling and various molecular mechanisms underlying iron-mediated drug resistance are described. A dual role of this vital element in cancer treatment is also addressed. On one hand, the need to administer iron chelators to surmount iron overload and improve the sensitivity of tumor cells to chemotherapy is discussed. On the other hand, the necessary application of iron as a therapeutic option by iron-oxide nanoparticles or ferroptosis inducers is explained. Authors hope that this paper can help unravel the clinical complications related to iron in cancer therapy.

Systematic Identification of Genomic Markers for Guiding Iron Oxide Nanoparticles in Cervical Cancer Based on Translational Bioinformatics

Purpose

Magnetic iron oxide nanoparticle (MNP) drug delivery system is a novel promising therapeutic option for cancer treatment. Material issues such as fabrication and functionalized modification have been investigated; however, pharmacologic mechanisms of bare MNPs inside cancer cells remain obscure. This study aimed to explore a systems pharmacology approach to understand the reaction of the whole cell to MNPs and suggest drug selection in MNP delivery systems to exert synergetic or additive anti-cancer effects.

Methods

HeLa and SiHa cell lines were used to estimate the properties of bare MNPs in cervical cancer through 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) and enzyme activity assays and cellular fluorescence imaging. A systems pharmacology approach was utilized by combining bioinformatics data mining with clinical data analysis and without a predefined hypothesis. Key genes of the MNP onco-pharmacologic mechanism in cervical cancer were identified and further validated through transcriptome analysis with quantitative reverse transcription PCR (qRT-PCR).

Results

Low cytotoxic activity and cell internalization of MNP in HeLa and SiHa cells were observed. Lysosomal function was found to be impaired after MNP treatment. Protein tyrosine kinase 2 beta (PTK2B), liprin-alpha-4 (PPFIA4), mothers against decapentaplegic homolog 7 (SMAD7), and interleukin (IL) 1B were identified as key genes relevant for MNP pharmacology, clinical features, somatic mutation, and immune infiltration. The four key genes also exhibited significant correlations with the lysosome gene set. The qRT-PCR results showed significant alterations in the expression of the four key genes after MNP treatment in HeLa and SiHa cells.

Conclusion

Our research suggests that treatment of bare MNPs in HeLa and SiHa cells induced significant expression changes in PTK2B, PPFIA4, SMAD7, and IL1B, which play crucial roles in cervical cancer development and progression. Interactions of the key genes with specific anti-cancer drugs must be considered in the rational design of MNP drug delivery systems.

Platinum–copper alloy nanoparticles armored with chloride ion transporter to promote electro-driven tumor inhibition

The induction of oxidative species, driven by oscillating electric field (E), has recently emerged as an effective approach for tumor inhibition, so-called electrodynamic therapy (EDT). While it offers a series of advantages attracting considerable attention, the fundamental mechanism and improvement strategies for EDT approach are being endeavored extensively with the aid of new material explorations. An interesting phenomenon observed in early studies is that the on-site concentration of chloride ion is highly favored for the induction of oxidative species and the efficacy of tumor inhibition. Following this discovery ignored previously, here for the first time, fine Pt/Cu alloy nanoparticles (PtCu₃ NPs) are integrated with chloride ion transporter (CIT) for EDT-based combinational therapy. In this system, while PtCu₃ NPs induce oxidative species under an electric field, it also effectively transforms endogenous H₂O₂ into •OH and consumes intracellular glutathione (GSH). More importantly, with the aid of CIT, PtCu₃-PEG@CIT NPs promote the intracellular concentration of chloride ion (Cl⁻) by transporting extracellular Cl⁻, facilitating the generation of oxidative species considerably. Meanwhile, CIT delivered intracellularly increases lysosomal pH, leading to the disruption of cellular autophagy and weakening the treatment resistance. In consequence, significant tumor inhibition is enabled both in vitro and in vivo, due to the combination of unique characteristics offered by PtCu₃-PEG@CIT.

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PtCu₃-PEG NPs present the effective ROS generation under electric field and CDT activity.

•PtCu₃-PEG NPs could consume GSH, inhibiting ROS clearance to enhance EDT and CDT.

•PtCu₃-PEG@CIT NPs promote intercellular chloride ion concentration, facilitating the ROS generation under electric field.

•CIT disrupts autophagy, weakening tumor cell resistance to ROS induced by PtCu₃-PEG NPs.

Nanoparticle-Mediated Photothermal Therapy Limitation in Clinical Applications Regarding Pain Management

The development of new effective cancer treatment methods has attracted much attention, mainly due to the limited efficacy and considerable side effects of currently used cancer treatment methods such as radiation therapy and chemotherapy. Photothermal therapy based on the use of plasmonically resonant metallic nanoparticles has emerged as a promising technique to eradicate cancer cells selectively. In this method, plasmonic nanoparticles are first preferentially uptaken by a tumor and then selectively heated by exposure to laser radiation with a specific plasmonic resonant wavelength, to destroy the tumor whilst minimizing damage to adjacent normal tissue. However, several parameters can limit the effectiveness of photothermal therapy, resulting in insufficient heating and potentially leading to cancer recurrence. One of these parameters is the patient's pain sensation during the treatment, if this is performed without use of anesthetic. Pain can restrict the level of applicable laser radiation, cause an interruption to the treatment course and, as such, affect its efficacy, as well as leading to a negative patient experience and consequential general population hesitancy to this type of therapy. Since having a comfortable and painless procedure is one of the important treatment goals in the clinic, along with its high effectiveness, and due to the relatively low number of studies devoted to this specific topic, we have compiled this review. Moreover, non-invasive and painless methods for temperature measurement during photothermal therapy (PTT), such as Raman spectroscopy and nanothermometry, will be discussed in the following. Here, we firstly outline the physical phenomena underlying the photothermal therapy, and then discuss studies devoted to photothermal cancer treatment concerning pain management and pathways for improved efficiency of photothermal therapy whilst minimizing pain experienced by the patient.

Targeting regulated cell death in tumor nanomedicines

Nanomedicines hold great potential in anticancer therapy by modulating the biodistribution of nanomaterials and initiating targeted oxidative stress damage, but they are also limited by the inherent self-protection mechanism and the evolutionary treatment resistance of cancer cells. New emerging explorations of regulated cell death (RCD), including processes related to autophagy, ferroptosis, pyroptosis, and necroptosis, substantially contribute to the augmented therapeutic efficiency of tumors by increasing the sensitivity of cancer cells to apoptosis. Herein, paradigmatic studies of RCD-mediated synergistic tumor nanotherapeutics are introduced, such as regulating autophagy-enhanced photodynamic therapy (PDT), targeting ferroptosis-sensitized sonodynamic therapy (SDT), inducing necroptosis-augmented photothermal therapy (PTT), and initiating pyroptosis-collaborative chemodynamic therapy (CDT), and the coordination mechanisms are discussed in detail. Multiangle analyses addressing the present challenges and upcoming prospects of RCD-based nanomedicines have also been highlighted and prospected for their further strengthening and the broadening of their application scope. It is believed that up-and-coming coadjutant therapeutic methodologies based on RCDs will considerably impact precision nanomedicine for cancer.

Autophagy-inhibiting biomimetic nanodrugs enhance photothermal therapy and boost antitumor immunity

The instinctive protective stress responses of tumor cells hamper the low-temperature photothermal therapy (LTPTT), resulting in tumor recurrence and metastasis. The rapid blood clearance and low-efficiency tumor enrichment of nanomedicines...

Magnetic nanoclusters mediated photothermal effect and macrophage modulation for synergistically photothermal immunotherapy of cancer

In tumor microenvironment, macrophages predominately exhibit M2-type functionalities which promote malignant progression and cancer metastasis, thus bring big hurdle to current anticancer strategies. Different approaches had been exploited to reverse...

Photoactivated Self-Disassembly of Multifunctional DNA Nanoflower Enables Amplified Autophagy Suppression for Low-Dose Photodynamic Therapy

Low-dose photodynamic therapy (PDT) holds great promise for reducing undesired patient photosensitivity in cancer treatment. Yet, its therapeutic effect is significantly affected by intracellular cytoprotective processes, such as autophagy. Here, an efficient autophagy suppressor is developed, which is a multifunctional DNA nanoflower (DNF) consisted of tumor-targeting aptamers and DNAzymes for silencing autophagy-related genes, with surface modification of low-dose photosensitizer (Ce6). It is found that the multifunctional DNF can specifically target tumor cells and generate reactive oxygen species (ROS) under light irradiation to trigger self-disassembly of DNF, enhancing the bioavailability of encoded DNAzymes, leading to amplified autophagy suppression. As a facile spatiotemporally programmable photogene therapy platform, the designed DNF is able to suppress tumor growth in vivo with a very low injection dose of Ce6 (18 µg kg^-1 , around 100 times lower than the generally applied dose), representing a promising strategy for cancer therapy with safely low-dose PDT.

Tumor targeting and penetrating biomimetic mesoporous polydopamine nanoparticles facilitate photothermal killing and autophagy blocking for synergistic tumor ablation

The synergistic manipulation of autophagy blocking with tumor targeting and penetration effects to enhance cancer cell killing during photothermal therapy (PTT) remains a substantial challenge. Herein, we fabricated a biomimetic nanoplatform by precisely coating homologous prostate cancer cell membranes (CMs) onto the surface of mesoporous polydopamine nanoparticles (mPDA NPs) encapsulating the autophagy inhibitor chloroquine (CQ) for synergistically manipulating PTT and autophagy for anticancer treatment. The resulting biomimetic mPDA@CMs NPs-CQ system could escape macrophage phagocytosis, overcome the vascular barrier, and home in the homologous prostate tumor xenograft with high tumor targeting and penetrating efficiency. The mPDA NPs core endowed the mPDA@CMs NPs-CQ with good photothermal capability to mediate PTT killing of prostate cancer cells, while NIR-triggered CQ release from the nanosystem further arrested PTT-induced protective autophagy of cancer cells, thus weakening the resistance of prostate cancer cells to PTT. This combined PTT killing and autophagy blocking anticancer strategy could induce significant autophagosome accumulation, ROS generation, mitochondrial damage, endoplasmic reticulum stress, and apoptotic signal transduction, which finally results in synergistic prostate tumor ablation in vivo. This prostate cancer biomimetic nanosystem with synergistically enhanced anticancer efficiency achieved by manipulating PTT killing and autophagy blocking is expected to serve as a more effective anticancer strategy against prostate cancer. STATEMENT OF SIGNIFICANCE: Autophagy is considered as one of the most efficient rescuer and reinforcement mechanisms of cancer cells against photothermal therapy (PTT)-induced cancer cell eradication. How to synergistically manipulate autophagy blocking with significant tumor targeting and penetration to enhance PTT-mediated cancer cell killing remains a substantial challenge. Herein, we fabricated a biomimetic nanoplatform by precisely coating homologous cancer cell membranes onto the surface of mesoporous polydopamine nanoparticles with encapsulation of the autophagy inhibitor chloroquine for synergistic antitumor treatment with high tumor targeting and penetrating efficiency both in vitro and in vivo. This biomimetic nanosystem with synergistically enhanced anticancer efficiency by manipulating PTT killing and autophagy blocking is expected to serve as a more effective anticancer strategy.

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.

Synthesis, morphological analysis, antibacterial activity of iron oxide nanoparticles and the cytotoxic effect on lung cancer cell line

Focusing on the huge importance associated in developing functional materials, this research study describes the synthesis, characterization of morphology, bactericidal activity and cytotoxic effect of iron oxide nanoparticles (IONPs). IONPs have been successfully fabricated through thermal decomposition of a diiron(III) complex precursor. The morphology of the nanoparticle has been delineated with different spectroscopic and analytic methods. Scanning and transmission electron microscopy (FE-SEM and HR-TEM) analyses estimate the cross linked porous structure of IONPs with an average size ~97 nm. Dynamic light scattering (DLS) study of IONPs determines the hydrodynamic diameter as 104 nm. The cytotoxic behavior of IONPs has been examined against human lung cancer cell line (A549) through different fluorescence staining studies which ensure the mode of apoptosis for cell death of A549. Furthermore, measurement of reactive oxygen species suggests the destruction of mitochondrial membrane of Staphylococcus aureus, leading to effective bactericidal propensity which holds a good promise for IONPs to become a clinically approved antibacterial agent.

Iron Oxide Nanoparticles as Autophagy Intervention Agents Suppress Hepatoma Growth by Enhancing Tumoricidal Autophagy

The combined treatment with nanoparticles and autophagy inhibitors, such as chloroquine (CQ) and hydroxychloroquine (HCQ), is extensively explored for cancer therapy. However, the toxicity of autophagy inhibitors and their unselective for tumoricidal autophagy have seriously hindered the application of the combined treatment. In this study, a carboxy-functional iron oxide nanoparticle (Fe2O3@DMSA) is designed and identified to significantly exert an antitumor effect without adding CQ or HCQ. Further investigation indicates that the effective inhibition effect of Fe2O3@DMSA alone on hepatoma growth is triggered by inhibiting the fusion of autophagosomes and lysosomes to enhance tumoricidal autophagy, which is induced by intracellular iron-retention-induced sustained reactive oxygen species (ROS) production. Furthermore, in two hepatoma-bearing mouse models, Fe2O3@DMSA alone effectively suppresses the growth of tumors without obvious toxic side effects. These studies offer a promising strategy for cancer therapy.

Green and Kilogram-Scale Synthesis of Fe Hydrogel for Photothermal Therapy of Tumors in Vivo

Photothermal agents with good biocompatibility, high tumor accumulation efficiency, large-scale production ability, and low cost are crucial for potential photothermal treatment in clinic. Herein, we proposed a green and highly efficient strategy to fabricate a kilogram-scale alginate-Ca²⁺-Fe powder hydrogel (ALG-Ca²⁺-Fe) by turning commercial Fe powder into hydrogel for enhanced photothermal therapy. The ALG-Ca²⁺-Fe was formed by simply dispersing commercial Fe powder into the preformed alginate-Ca²⁺ hydrogel in a green and energy-/time-saving way. The hydrogel exhibited the advantages of ultrahigh loading capacity of Fe powder (>100 mg mL^-1), excellent large-scale production capacity (>1 kg in lab synthesis), low cost (<1.7 $/kg), and good injectability. More importantly, large size and hydrophobicity endowed Fe powder with excellent tumor retention effect and minimal diffusion to surrounding tissues, greatly benefiting improving treatment efficiency and reducing side effects. In vivo and in vitro studies both proved that the large-scale produced ALG-Ca²⁺-Fe can be used for highly efficient and biosafe tumor treatment in vivo by simple noninvasive injection. The developed ALG-Ca²⁺-Fe with multiple superiors opens up a novel green way to develop efficient and safe photothermal therapeutic agents with great clinic transformation potential.

Targeting non-apoptotic cell death in cancer treatment by nanomaterials: Recent advances and future outlook

Many tumors develop resistance to most of the apoptosis-based cancer therapies. In this sense targeting non-apoptotic forms of cell death including necroptosis, autophagy and ferroptosis may have therapeutic benefits in apoptosis-defective cancer cells. Nanomaterials have shown great advantages in cancer treatment owing to their unique characteristics. Besides, the capability of nanomaterials to induce different forms of cell death has gained widespread attention in cancer treatment. Reports in this field reflect the therapeutic potential of necroptotic cell death induced by nanomaterials in cancer. Also, autophagic cell death induced by nanomaterials alone and as a part of chemo-, radio- and photothermal therapy holds great promise as anticancer therapeutic option. Besides, ferroptosis induction by iron-based nanomaterials in drug delivery, immunotherapy, hyperthermia and imaging systems shows promising results in malignancies. Hence, this review is devoted to the latest efforts and the challenges in this field of research and its clinical merits.

Progressive lysosomal membrane permeabilization induced by iron oxide nanoparticles drives hepatic cell autophagy and apoptosis

Iron oxide nanoparticles (IONs) are frequently used in various biomedical applications, in particular as magnetic resonance imaging contrast agents in liver imaging. Indeed, number of IONs have been withdrawn due to their poor clinical performance. Yet comprehensive understanding of their interactions with hepatocytes remains relatively limited. Here we investigated how iron oxide nanocubes (IO-cubes) and clusters of nanocubes (IO-clusters) affect distinct human hepatic cell lines. The viability of HepG2, Huh7 and Alexander cells was concentration-dependently decreased after exposure to either IO-cubes or IO-clusters. We found similar cytotoxicity levels in three cell lines triggered by both nanoparticle formulations. Our data indicate that different expression levels of Bcl-2 predispose cell death signaling mediated by nanoparticles. Both nanoparticles induced rather apoptosis than autophagy in HepG2. Contrary, IO-cubes and IO-clusters trigger distinct cell death signaling events in Alexander and Huh7 cells. Our data clarifies the mechanism by which cubic nanoparticles induce autophagic flux and the mechanism of subsequent toxicity. These findings imply that the cytotoxicity of ION-based contrast agents should be carefully considered, particularly in patients with liver diseases.

Initiation of protective autophagy in hepatocytes by gold nanorod core/silver shell nanostructures

The high reactivity of silver nanoparticles leads to their broad applications in the anti-bacterial field; however, the safety of silver nanoparticles has attracted increasing public attention. After exposure to silver nanoparticles in vivo, the liver serves as their potential deposition site; however the potential biological effects of such nanoparticles on hepatocytes at low dosages are not well understood. Here, we study the interaction between gold nanorod core/silver shell nanostructures (Au@Ag NRs) and human hepatocytes, HepG2 cells, and determine that Au@Ag NRs at sub-lethal doses can induce autophagy. After uptake, Au@Ag NRs mainly localize in the lysosomes where they release silver ions and promote the production of reactive oxygen species (ROS). The ROS then suppress the AKT-mTOR signaling pathway and activate autophagy. In addition, oxidative stress results in lysosomal impairment, causing decreased ability for lysosomal digestion. Moreover, oxidative stress also affects the structure and function of mitochondria, leading to the initiation of protective autophagy to eliminate the damaged mitochondrion. Our study shows that at sub-lethal dosages, silver nanomaterials may alter the physiological functions of hepatic cells by activating protective autophagy and cause potential health risks, indicating that cautious consideration of the safety of nanomaterials for certain applications is necessary.

Ultrafast Low-Temperature Photothermal Therapy Activates Autophagy and Recovers Immunity for Efficient Antitumor Treatment

Conventional therapeutic approaches to treat malignant tumors such as surgery, chemotherapy, or radiotherapy often lead to poor therapeutic results, great pain, economic burden, and risk of recurrence and may even increase the difficulty in treating the patient. Long-term drug administration and systemic drug delivery for cancer chemotherapy would be accompanied by drug resistance or unpredictable side effects. Thus, the use of photothermal therapy, a relatively rapid tumor elimination technique that regulates autophagy and exerts an antitumor effect, represents a novel solution to these problems. Heat shock protein 90 (HSP90), a protein that reduces photothermal or hypothermic efficacy, is closely related to AKT (protein kinase B) and autophagy. Therefore, it was hypothesized that autophagy could be controlled to eliminate tumors by combining exogenous light with a selective HSP90 inhibitor, for example, SNX-2112. In this study, an efficient tumor-killing strategy using graphene oxide loaded with SNX-2112 and folic acid for ultrafast low-temperature photothermal therapy (LTPTT) is reported. A unique mechanism that achieves remarkable therapeutic performance was discovered, where overactivated autophagy induced by ultrafast LTPTT led to direct apoptosis of tumors and enabled functional recovery of T cells to promote natural immunity for actively participating in the attack against tumors. This LTPTT approach resulted in residual tumor cells being rendered in an "injured" state, opening up the possibility of concurrent antitumor and antirecurrence treatment.

Hierarchical assembly of dual-responsive biomineralized polydopamine–calcium phosphate nanocomposites for enhancing chemo-photothermal therapy by autophagy inhibition

Hierarchically assembled biomineralized nanocomposites would be used to sensitize chemo-photothermal therapy by complementary autophagy inhibition.

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.

Polyethyleneimine coated Fe3O4 magnetic nanoparticles induce autophagy, NF-κB and TGF-β signaling pathway activation in HeLa cervical carcinoma cells via reactive oxygen species generation

Fe₃O₄ magnetic nanoparticles (MNPs), as one of the most intensively researched NPs, have a range of applications in cancer treatments. In current research, we have focused on the influences of MNPs on cancer cells. We chose polyethyleneimine (PEI) coated MNPs (PEI-MNPs) as a model and they are colloidally stable in biological media. It can be proved that PEI-MNPs result in autophagy induction via mTOR-Akt-p70S6 K and ATG7 signaling pathways. For the first time, we have reported that PEI-MNPs activate both NF-κB and TGF-β signaling, two key pro-inflammatory pathways, in cancer cells. More significantly, we have found that autophagy induction and NF-κB and TGF-β activation can be efficiently suppressed through the inhibition of PEI-MNP dependent reactive oxygen species (ROS) over-production. ROS are deemed as a 'double edge sword' for cancer cells, owing to the cancer-suppressing and cancer-promoting actions. Our findings would be useful for designing MNPs induced ROS anti-cancer strategies or diminishing long-term toxic effects.

Targeting Autophagy for Cancer Treatment and Tumor Chemosensitization

Autophagy is a tightly regulated catabolic process that facilitates nutrient recycling from damaged organelles and other cellular components through lysosomal degradation. Deregulation of this process has been associated with the development of several pathophysiological processes, such as cancer and neurodegenerative diseases. In cancer, autophagy has opposing roles, being either cytoprotective or cytotoxic. Thus, deciphering the role of autophagy in each tumor context is crucial. Moreover, autophagy has been shown to contribute to chemoresistance in some patients. In this regard, autophagy modulation has recently emerged as a promising therapeutic strategy for the treatment and chemosensitization of tumors, and has already demonstrated positive clinical results in patients. In this review, the dual role of autophagy during carcinogenesis is discussed and current therapeutic strategies aimed at targeting autophagy for the treatment of cancer, both under preclinical and clinical development, are presented. The use of autophagy modulators in combination therapies, in order to overcome drug resistance during cancer treatment, is also discussed as well as the potential challenges and limitations for the use of these novel therapeutic strategies in the clinic.

Plasmonic Photothermal Nanoparticles for Biomedical Applications

Recent advances of plasmonic nanoparticles include fascinating developments in the fields of energy, catalyst chemistry, optics, biotechnology, and medicine. The plasmonic photothermal properties of metallic nanoparticles are of enormous interest in biomedical fields because of their strong and tunable optical response and the capability to manipulate the photothermal effect by an external light source. To date, most biomedical applications using photothermal nanoparticles have focused on photothermal therapy; however, to fully realize the potential of these particles for clinical and other applications, the fundamental properties of photothermal nanoparticles need to be better understood and controlled, and the photothermal effect-based diagnosis, treatment, and theranostics should be thoroughly explored. This Progress Report summarizes recent advances in the understanding and applications of plasmonic photothermal nanoparticles, particularly for sensing, imaging, therapy, and drug delivery, and discusses the future directions of these fields.

Bismuth embedded silica nanoparticles loaded with autophagy suppressant to promote photothermal therapy

An unpredicted side effect of photothermal therapy (PTT) is agitated by hyperthermia which results in damage to healthy tissue. Developing PTT platforms, enabling effective tumor ablation under mild irradiation conditions, is of wide interest, but challenging. Here, we investigated bismuth crystals embedded silica (Bi@SiO₂) nanoparticles, loaded with an autophagy inhibitor (chloroquine, CQ). It was found that SiO₂ effectively prevented the oxidization of Bi nanocrystals in the physiological environment and could serve as a scatter layer to improve NIR absorption, enabling a high photothermal conversion efficiency (~43%) and excellent photostability. Furthermore, the findings indicated that CQ molecules, delivered intracellularly by the particles, significantly weakened the degradation of autolysosomes by lysosome within the tumor cells, thus inducing suppression effect to autophagy and resistance to photothermia. Both in vitro and in vivo anti-tumor effects were consequently promoted owing to the combined effects enabled by Bi@SiO₂-CQ nanoparticles under mild NIR irradiation conditions. This study demonstrates a potential new PTT platform with superior therapeutic efficacy.

Actively priming autophagic cell death with novel transferrin receptor-targeted nanomedicine for synergistic chemotherapy against breast cancer

Recently, considerable attention in the field of cancer therapy has been focused on the mammalian rapamycin target (mTOR), inhibition of which could result in autophagic cell death (ACD). Though novel combination chemotherapy of autophagy inducers with chemotherapeutic agents is extensively investigated, nanomedicine-based combination therapy for ACD remains in infancy. In attempt to actively trigger ACD for synergistic chemotherapy, here we incorporated autophagy inducer rapamycin (RAP) into 7pep-modified PEG-DSPE polymer micelles (7pep-M-RAP) to specifically target and efficiently priming ACD of MCF-7 human breast cancer cells with high expression of transferrin receptor (TfR). Cytotoxic paclitaxel (PTX)-loaded micelle (7pep-M-PTX) was regarded as chemotherapeutic drug model. We discovered that with superior intracellular uptake in vitro and more tumor accumulation of micelles in vivo, 7pep-M-RAP exhibited excellent autophagy induction and synergistic antitumor efficacy with 7pep-M-PTX. Mechanism study further revealed that 7pep-M-RAP and 7pep-M-PTX used in combination provided enhanced efficacy through induction of both apoptosis- and mitochondria-associated autophagic cell death. Together, our findings suggested that the targeted excess autophagy may provide a rational strategy to improve therapeutic outcome of breast cancer, and simultaneous induction of ACD and apoptosis may be a promising anticancer modality.

Remote Magnetic Control of Autophagy in Mouse B-Lymphoma Cells with Iron Oxide Nanoparticles

Autophagy is the spontaneous degradation of intracellular proteins and organelles in response to nutrient deprivation. The phagocytosis of iron oxide nanoparticles (IONPs) results in intracellular degradation that can be exploited for use in cancer treatment. Non-invasive magnetic control has emerged as an important technology, with breakthroughs achieved in areas such as magneto-thermal therapy and drug delivery. This study aimed to regulate autophagy in mouse B-lymphoma cells (A20) through the incorporation of IONPs-quantum dots (QDs). We hypothesized that with the application of an external magnetic field after phagocytosis of IONPs-QDs, autophagy of intracellular IONPs-QDs could be regulated in a non-invasive manner and subsequently modulate the regulation of inflammatory responses. The potential of this approach as a cancer treatment method was explored. The application of IONPs and an external magnetic force enabled the non-invasive regulation of cell autophagy and modulation of the self-regulatory function of cells. The combination of non-invasive magnetic fields and nanotechnology could provide a new approach to cancer treatment.

Targeting autophagy using metallic nanoparticles: a promising strategy for cancer treatment

Despite the extensive genetic and phenotypic variations present in the different tumors, they frequently share common metabolic alterations, such as autophagy. Autophagy is a self-degradative process in response to stresses by which damaged macromolecules and organelles are targeted by autophagic vesicles to lysosomes and then eliminated. It is known that autophagy dysfunctions can promote tumorigenesis and cancer development, but, interestingly, its overstimulation by cytotoxic drugs may also induce cell death and chemosensitivity. For this reason, the possibility to modulate autophagy may represent a valid therapeutic approach to treat different types of cancers and a variety of clinical trials, using autophagy modulators, are currently employed. On the other hand, recent progress in nanotechnology offers plenty of tools to fight cancer with innovative and efficient therapeutic agents by overcoming obstacles usually encountered with traditional drugs. Interestingly, nanomaterials can modulate autophagy and have been exploited as therapeutic agents against cancer. In this article, we summarize the most recent advances in the application of metallic nanostructures as potent modulators of autophagy process through multiple mechanisms, stressing their therapeutic implications in cancer diseases. For this reason, we believe that autophagy modulation with nanoparticle-based strategies would acquire clinical relevance in the near future, as a complementary therapy for the treatment of cancers and other diseases.

An ATP-Regulated Ion Transport Nanosystem for Homeostatic Perturbation Therapy and Sensitizing Photodynamic Therapy by Autophagy Inhibition of Tumors

In this article, an adenosine-triphosphate-regulated (ATP-regulated) ion transport nanosystem [SQU@PCN, porphyrinic porous coordination network (PCN) incorporated with squaramide (SQU)] was designed and synthesized for homeostatic perturbation therapy (HPT) and sensitizing photodynamic therapy (PDT) of tumors. It was found that this nanotransporter SQU@PCN easily accumulated in tumor sites while avoiding metabolic clearance and side effects. In response to a high expression of ATP in the tumor, SQU@PCN was decomposed because of the strong coordination of ATP with metal ligand of PCN. Subsequently, incorporated SQU was released and then simultaneously transported chloride ions across membrane of the cell and lysosome along with the chloride ion concentration gradient. On one hand, influx of chloride ions by SQU increased intracellular ion concentration, which disrupted ion homeostasis and further induced tumor cell apoptosis. On the other hand, SQU-medicated coupling transport of H+/Cl- across the lysosomal membrane alkalized the lysosome, resulting in inhibition of autophagy. This SQU-mediated autophagy inhibition would sensitize PCN-based PDT since activated autophagy by traditional PDT would resist and weaken the therapeutic efficacy. In vivo animal test results revealed that combined HPT and sensitized PDT could realize tumor eradication while blocking metastasis, which provided a paradigm for complementary multimodal tumor treatment.

Exploiting Nanomaterial-mediated Autophagy for Cancer Therapy

Autophagy is a conserved process that is critical for sequestering and degrading proteins, damaged or aged organelles, and for maintaining cellular homeostasis under stress conditions. Despite its dichotomous role in health and diseases, autophagy usually promotes growth and progression of advanced cancers. In this context, clinical trials using chloroquine and hydroxychloroquine as autophagy inhibitors have suggested that autophagy inhibition is a promising approach for treating advanced malignancies and/or overcoming drug resistance of small molecule therapeutics (i.e., chemotherapy and molecularly targeted therapy). Efficient delivery of autophagy inhibitors may further enhance the therapeutic effect, reduce systemic toxicity, and prevent drug resistance. As such, nanocarriers-based drug delivery systems have several distinct advantages over free autophagy inhibitors that include increased circulation of the drugs, reduced off-target systemic toxicity, increased drug delivery efficiency, and increased solubility and stability of the encapsulated drugs. With their versatile drug encapsulation and surface-functionalization capabilities, nanocarriers can be engineered to deliver autophagy inhibitors to tumor sites in a context-specific and/or tissue-specific manner. This review focuses on the role of nanomaterials utilizing autophagy inhibitors for cancer therapy, with a focus on their applications in different cancer types.

Iron Metabolism in Cancer

Demanded as an essential trace element that supports cell growth and basic functions, iron can be harmful and cancerogenic though. By exchanging between its different oxidized forms, iron overload induces free radical formation, lipid peroxidation, DNA, and protein damages, leading to carcinogenesis or ferroptosis. Iron also plays profound roles in modulating tumor microenvironment and metastasis, maintaining genomic stability and controlling epigenetics. in order to meet the high requirement of iron, neoplastic cells have remodeled iron metabolism pathways, including acquisition, storage, and efflux, which makes manipulating iron homeostasis a considerable approach for cancer therapy. Several iron chelators and iron oxide nanoparticles (IONPs) has recently been developed for cancer intervention and presented considerable effects. This review summarizes some latest findings about iron metabolism function and regulation mechanism in cancer and the application of iron chelators and IONPs in cancer diagnosis and therapy.