The effect of autophagy inhibitors on drug delivery using biodegradable polymer nanoparticles in cancer treatment

Guidelines for the role of autophagy in drug delivery vectors uptake pathways

The process of autophagy refers to the intracellular absorption of cytoplasm (such as proteins, nucleic acids, tiny molecules, complete organelles, and so on) into the lysosome, followed by the breakdown of that cytoplasm. The majority of cellular proteins are degraded by a process called autophagy, which is both a naturally occurring activity and one that may be induced by cellular stress. Autophagy is a system that can save cells' integrity in stressful situations by restoring metabolic basics and getting rid of subcellular junk. This happens as a component of an endurance response. This mechanism may have an effect on disease, in addition to its contribution to the homeostasis of individual cells and tissues as well as the control of development in higher species. The main aim of this study is to discuss the guidelines for the role of autophagy in drug delivery vector uptake pathways. In this paper, we discuss the meaning and concept of autophagy, the mechanism of autophagy, the role of autophagy in drug delivery vectors, autophagy-modulating drugs, nanostructures for delivery systems of autophagy modulators, etc. Later in this paper, we talk about how to deliver chemotherapeutics, siRNA, and autophagy inducers and inhibitors. We also talk about how hard it is to make a drug delivery system that takes nanocarriers' roles as autophagy modulators into account.

Nanoplatform-Mediated Autophagy Regulation and Combined Anti-Tumor Therapy for Resistant Tumors

The overall cancer incidence and death toll have been increasing worldwide. However, the conventional therapies have some obvious limitations, such as non-specific targeting, systemic toxic effects, especially the multidrug resistance (MDR) of tumors, in which, autophagy plays a vital role. Therefore, there is an urgent need for new treatments to reduce adverse reactions, improve the treatment efficacy and expand their therapeutic indications more effectively and accurately. Combination therapy based on autophagy regulators is a very feasible and important method to overcome tumor resistance and sensitize anti-tumor drugs. However, the less improved efficacy, more systemic toxicity and other problems limit its clinical application. Nanotechnology provides a good way to overcome this limitation. Co-delivery of autophagy regulators combined with anti-tumor drugs through nanoplatforms provides a good therapeutic strategy for the treatment of tumors, especially drug-resistant tumors. Notably, the nanomaterials with autophagy regulatory properties have broad therapeutic prospects as carrier platforms, especially in adjuvant therapy. However, further research is still necessary to overcome the difficulties such as the safety, biocompatibility, and side effects of nanomedicine. In addition, clinical research is also indispensable to confirm its application in tumor treatment.

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.

Conjugated Nanoparticles for Solid Tumor Theranostics: Unraveling the Interplay of Known and Unknown Factors

Cancer diagnoses have been increasing worldwide, and solid tumors are among the leading contributors to patient mortality, creating an enormous burden on the global healthcare system. Cancer is responsible for around 10.3 million deaths worldwide. Solid tumors are one of the most prevalent cancers observed in recent times. On the other hand, early diagnosis is a significant challenge that could save a person's life. Treatment with existing methods has pitfalls that limit the successful elimination of the disorder. Though nanoparticle-based imaging and therapeutics have shown a significant impact in healthcare, current methodologies for solid tumor treatment are insufficient. There are multiple complications associated with the diagnosis and management of solid tumors as well. Recently, surface-conjugated nanoparticles such as lipid nanoparticles, metallic nanoparticles, and quantum dots have shown positive results in solid tumor diagnostics and therapeutics in preclinical models. Other nanotheranostic material platforms such as plasmonic theranostics, magnetotheranostics, hybrid nanotheranostics, and graphene theranostics have also been explored. These nanoparticle theranostics ensure the appropriate targeting of tumors along with selective delivery of cargos (both imaging and therapeutic probes) without affecting the surrounding healthy tissues. Though they have multiple applications, nanoparticles still possess numerous limitations that need to be addressed in order to be fully utilized in the clinic. In this review, we outline the importance of materials and design strategies used to engineer nanoparticles in the treatment and diagnosis of solid tumors and how effectively each method overcomes the drawbacks of the current techniques. We also highlight the gaps in each material platform and how design considerations can address their limitations in future research directions.

Dual role of autophagy for advancements from conventional to new delivery systems in cancer

Autophagy, a programmed cell-lysis mechanism, holds significant promise in the prevention and treatment of a wide range of conditions, including cancer, Alzheimer's, and Parkinson's disease. The successful utilization of autophagy modulation for therapeutic purposes hinges upon accurately determining the role of autophagy in disease progression, whether it acts as a cytotoxic or cytoprotective factor. This critical knowledge empowers scientists to effectively manipulate tumor sensitivity to anti-cancer therapies through autophagy modulation, while also circumventing drug resistance. However, conventional therapies face limitations such as low bioavailability, poor solubility, and a lack of controlled release mechanisms, hindering their clinical applicability. In this regard, innovative nanoplatforms including organic and inorganic systems have emerged as promising solutions to offer stimuli-responsive, theranostic-controlled drug delivery systems with active targeting and improved solubility. The review article explores a variety of organic nanoplatforms, such as lipid-based, polymer-based, and DNA-based systems, which incorporate autophagy-inhibiting drugs like hydroxychloroquine. By inhibiting the glycolytic pathway and depriving cells of essential nutrients, these platforms exhibit tumor-suppressive effects in advanced forms of cancer such as leukemia, colon cancer, and glioblastoma. Furthermore, metal-based, metal-oxide-based, silica-based, and quantum dot-based nanoplatforms selectively induce autophagy in tumors, leading to extensive cancer cell destruction. Additionally, this article discusses the current clinical status of autophagy-modulating drugs for cancer therapy with valuable insights of progress and potential of such approaches.

Autophagy and Biomaterials: A Brief Overview of the Impact of Autophagy in Biomaterial Applications

Macroautophagy (hereafter autophagy), a tightly regulated physiological process that obliterates dysfunctional and damaged organelles and proteins, has a crucial role when biomaterials are applied for various purposes, including diagnosis, treatment, tissue engineering, and targeted drug delivery. The unparalleled physiochemical properties of nanomaterials make them a key component of medical strategies in different areas, such as osteogenesis, angiogenesis, neurodegenerative disease treatment, and cancer therapy. The application of implants and their modulatory effects on autophagy have been known in recent years. However, more studies are necessary to clarify the interactions and all the involved mechanisms. The advantages and disadvantages of nanomaterial-mediated autophagy need serious attention in both the biological and bioengineering fields. In this mini-review, the role of autophagy after biomaterial exploitation and the possible related mechanisms are explored.

Autophagy-induced intracellular signaling fractional nano-drug system for synergistic anti-tumor therapy

Autophagy inducers increase the sensitivity of tumor cells to chemotherapeutic drugs and enhance anti-tumor efficacy. An autophagy-induced intracellular signaling fractional nano-drug system was constructed for the co-delivery of the autophagy inducer rapamycin (RAPA) and the anti-tumor drug 9-nitro-20(S)-camptothecin (9-NC). Link peptides, including cathepsin B-sensitive peptides (Ala-Leu-Ala-Leu, ALAL), nucleus-targeting peptides (TAT, sequence: YGRKKRRQRRR), and chrysin (CHR)-modified hydrophobic biodegradable polymers (poly(-caprolactone)) (PCL), were grafted onto hyaluronic acid (HA) to yield two amphiphiles, HA-ALAL-PCL-CHR (CPAH) and HA-ALAL-TAT-PCL-CHR (CPTAH). Spherical RAPA- and 9-NC-loaded micelles were obtained by the self-assembly of amphiphiles comprising CPAH and RAPA and CPTAH and 9-NC. In this fractional nano-drug system, RAPA was released earlier than 9-NC, as CPAH as a RAPA carrier lacked a nucleus-targeting TAT (unlike CPTAH as an 9-NC carrier). RAPA induced autophagy in tumor cells and improved their sensitivity, whereas the secondary nucleus-targeting micelles directly delivered 9-NC to the nucleus, considerably improving anti-tumor efficacy. Immunofluorescence staining, acridine orange (AO) staining, and western blotting results demonstrated that the system induced a high level of autophagy in combination chemotherapy. The proposed system possesses a high level of cytotoxicity in vitro and in vivo and provides a potential method for enhancing anti-tumor efficacy in clinical settings.

Nanocomplexes of doxorubicin and DNA fragments for efficient and safe cancer chemotherapy

Cancer-targeted therapy by a chemotherapeutic agent formulated in a nanoscale platform has been challenged by complex and inefficient manufacturing, low drug loading, difficult characterization, and marginally improved therapeutic efficacy. This study investigated facile-to-produce nanocomplexes of doxorubicin (DOX), a widely used cancer drug, and clinically approved DNA fragments that are extracted from a natural source. DOX was found to self-assemble DNA fragments into relatively monodispersed nanocomplexes with a diameter of ∼70 nm at 14.3% (w/w) drug loading by simple and scalable mixing. The resulting DOX/DNA nanocomplexes showed sustained DOX release, unlike overly stable Doxil®, cellular uptake via multiple endocytosis pathways, and high hematological and immunological compatibility. DOX/DNA nanocomplexes eradicated EL4 T lymphoma cells in a time-dependent manner, eventually surpassing free DOX. Extended circulation of DOX/DNA nanocomplexes, while avoiding off-target accumulation in the lung and being cleared from the liver, resulted in rapid accumulation in tumor and lowered cardio toxicity. Finally, tumor growth of EL4-challenged C57BL/6 mice (syngeneic model) and OPM2-challenged NSG mice (human xenograft model) were efficiently inhibited by DOX/DNA nanocomplexes with enhanced overall survival, in comparison with free DOX and Doxil®, especially upon repeated administrations. DOX/DNA nanocomplexes are a promising chemotherapeutics delivery platform for their ease of manufacturing, high biocompatibility, desired drug release and accumulation, efficient tumor eradication with improved safety, and further engineering versatility for extended therapeutic applications.

Macrophage-evading and tumor-specific apoptosis inducing nanoparticles for targeted cancer therapy

Extended circulation of anticancer nanodrugs in blood stream is essential for their clinical applications. However, administered nanoparticles are rapidly sequestered and cleared by cells of the mononuclear phagocyte system (MPS). In this study, we developed a biomimetic nanosystem that is able to efficiently escape MPS and target tumor tissues. The fabricated nanoparticles (TM-CQ/NPs) were coated with fibroblast cell membrane expressing tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL). Coating with this functionalized membrane reduced the endocytosis of nanoparticles by macrophages, but increased the nanoparticle uptake in tumor cells. Importantly, this membrane coating specifically induced tumor cell apoptosis via the interaction of TRAIL and its cognate death receptors. Meanwhile, the encapsulated chloroquine (CQ) further suppressed the uptake of nanoparticles by macrophages, and synergized with TRAIL to induce tumor cell apoptosis. The vigorous antitumor efficacy in two mice tumor models confirmed our nanosystem was an effective approach to address the MPS challenge for cancer therapy. Together, our TM-CQ/NPs nanosystem provides a feasible approach to precisely target tumor tissues and improve anticancer efficacy.

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.

Effects of polymer carriers on the occurrence and development of autophagy in drug delivery

Autophagy is an evolutionarily conserved catabolic process that can degrade cytoplasmic materials and recycle energy to maintain metabolite homeostasis in cells. Autophagy is closely related to various physiological or pathological processes. Macromolecular materials are widely used in drug delivery systems and disease treatments due to their intrinsic effects, such as altered pharmacokinetics and biodistribution. Interaction of autophagic flux or the signal pathway with macromolecules may cause autophagy inhibition or autophagy cell death. This review covers autophagy regulation pathways and macromolecular materials (including functional micelles, biodegradable and pH-sensitive polymers, biomacromolecules, dendrimers, coordination polymers, and hybrid nanoparticles) mediated autophagy modulation.

Probing the Intracellular Delivery of Nanoparticles into Hard-to-Transfect Cells

Hard-to-transfect cells are cells that are known to present special difficulties in intracellular delivery of exogenous entities. However, the special transport behaviors underlying the special delivery problem in these cells have so far not been examined carefully. Here, we combine single-particle motion analysis, cell biology studies, and mathematical modeling to investigate nanoparticle transport in bone marrow-derived mesenchymal stem cells (BMSCs), a technologically important type of hard-to-transfect cells. Tat peptide-conjugated quantum dots (QDs-Tat) were used as the model nanoparticles. Two different yet complementary single-particle methods, namely, pair-correlation function and single-particle tracking, were conducted on the same cell samples and on the same viewing stage of a confocal microscope. Our results reveal significant differences in each individual step of transport of QDs-Tat in BMSCs vs a commonly used model cell line, HeLa cells. Single-particle motion analysis demonstrates that vesicle escape and cytoplasmic diffusion are dramatically more difficult in BMSCs than in HeLa cells. Cell biology studies show that BMSCs use different biological pathways for the cellular uptake, vesicular transport, and exocytosis of QDs-Tat than HeLa cells. A reaction-diffusion-advection model is employed to mathematically integrate the individual steps of cellular transport and can be used to predict and design nanoparticle delivery in BMSCs. This work provides dissective, quantitative, and mechanistic understandings of nanoparticle transport in BMSCs. The investigative methods described in this work can help to guide the tailored design of nanoparticle-based delivery in specific types and subtypes of hard-to-transfect cells.

In Vitro Therapeutic Attributes of Luminescent Hydroxyapatite Nanoparticles in Codelivery Module

Imminent prospects of clinical importance have been accomplished through divergent treatment modalities implemented using nanoscale platforms. In the present study, hydroxyapatite nanoparticles doped with copper nanoclusters (HAPs) were explored for codelivery of a hydrophobic drug, namely, norfloxacin (NX), and a hydrophilic photosensitizer, such as methylene blue (MB). NX and MB were successfully homed into HAPs (MB-NX-HAPs), which further exhibited a pH-dependent release of both. With the objective of attaining an enhanced effect, MB-NX-HAPs were evaluated for combination therapy, involving chemotherapy and photodynamic therapy (PDT) with irradiation at 640 nm. The combinatorial therapy approach was initially applied for antibacterial therapy, which suggested a considerable reduction in bacterial growth of Gram-negative strain Pseudomonas aeruginosa MTCC 2488. Thereafter, the antiproliferative study performed in cancer cell lines (HeLa and MCF-7) revealed the efficiency of MB-NX-HAPs in bestowing a combinatorial effect through chemotherapy and PDT (irradiation at 640 nm). The combined effect exerted through MB-NX-HAPs subsequently induced reactive oxygen species (ROS) generation, cell cycle alteration, and apoptosis activation in cancer cells. The biocompatible nature of MB-NX-HAPs was appreciably shown through their minimal effect on the normal cell line (HEK-293). Additionally, HAPs through luminescence of copper nanoclusters were suggested to aid in bioimaging of cancer cell lines.

Spiky Cascade Biocatalysts as Peroxisome-Mimics for Ultrasound-Augmented Tumor Ablation

Ultrasound (US)-augmented tumor ablation with sono-catalysts has emerged as a promising therapeutic modality due to high tissue penetration, nonionizing performance, and low cost of US-based therapies. Developing peroxisome-mimetic cascade biocatalysts for US-augmented synergistic treatment would further effectively reduce the dependence of the microenvironment H₂O₂ and enhance the tumor-localized reactive oxygen species (ROS) generation. Here, we proposed and synthesized a novel spiky cascade biocatalyst as peroxisome-mimics that consist of multiple enzyme-mimics, i.e., glucose oxidase-mimics (Au nanoparticles for producing H₂O₂) and heme-mimetic atomic catalytic centers (Fe-porphyrin for ROS generation), for US-augmented cascade-catalytic tumor therapy. The synthesized spiky cascade biocatalysts exhibit an obvious spiky structure, uniform nanoscale size, independent of endogenous H₂O₂, and efficient US-responsive biocatalytic activities. The enzyme-mimetic biocatalytic experiments show that the spiky cascade biocatalysts can generate abundant ·OH via a cascade chemodynamic path and also ¹O₂ via US excitation. Then, we demonstrate that the spiky cascade biocatalysts show highly efficient ROS production to promote melanoma cell apoptosis under US irradiation without extra H₂O₂. Our in vivo animal data further reveal that the proposed US-assisted chemodynamic cascade therapies can significantly augment the therapy efficacy of malignant melanoma. We suggest that these efficient peroxisome-mimetic cascade-catalytic strategies will be promising for clinical tumor therapies.

The Emerging Role of Ultrasonic Nanotechnology for Diagnosing and Treatment of Diseases

Nanotechnology has been commonly used in a variety of applications in recent years. Nanomedicine has also gotten a lot of attention in the medical and treatment fields. Ultrasonic technology is already being used in research as a powerful tool for manufacturing nonmaterial and in the decoration of catalyst supports for energy applications and material processing. For the development of nanoparticles and the decoration of catalytic assisted powders with nanoparticles, low or high-frequency Ultrasonic are used. The Ultrasonic is frequently used in joint venture with the nanotechnology from the past few years and bring tremendous success in various diseases diagnosing and treatment. Numerous kinds of nanoparticles are fabricated with desired capabilities and targeted toward different targets. This review first highlights the Ultrasonic Treatment and processing of Nanoparticles for Pharmaceuticals. Next, we explain various nanoparticles with ultrasonic technology for different diagnosing and treatment of various diseases. Finally, we explain the challenges face by current approaches for their translation in clinics.

Hierarchical MOF-on-MOF Architecture for pH/GSH-Controlled Drug Delivery and Fe-Based Chemodynamic Therapy

Chemotherapy is still an important and effective clinical treatment for cancer. However, individual drugs hardly achieve precise controlled release and targeted therapy, thus resulting in unavoidable side effects. Fortunately, the emergence of drug carriers is expected to solve the above problems. In this work, the MOF-on-MOF strategy was adopted to encapsulate DOX into double-layer NH₂-MIL-88B to fabricate a core-shell-structured DOX@NH₂-MIL-88B-On-NH₂-MIL-88B (DMM) and then realize the pH and GSH dual-responsive controlled DOX release. Because of the core-shell structure, the drug-loading capacity of DMM reached 14.4 wt %, which was nearly twice that of DOX@NH₂-MIL-88B (DM), and the controlled release performance of DMM was also improved at the same time, greatly improving the kinetics equilibrium time of DOX from 2 h (DM) to 16 h (DMM) at pH 5.0. Moreover, we found that DMM also possessed peroxidase-like catalytic activity under acidic conditions, which could catalyze H₂O₂ to produce ^•OH, exhibiting the potential chemodynamical treatment of cancer. Cell experiments showed that DMM had a significant inhibitory effect against 4T1 cancer cells, and the survival rate of 4T1 cells was less than 20% at 100 ppm.

An autophagy-inhibitory MOF nanoreactor for tumor-targeted synergistic therapy

An autophagy-inhibitory metal-organic framework (MOF) nanoreactor was developed for tumor-targeted synergistic therapy. The nanoreactor could inhibit autophagy to enhance the glucose oxidase (GOx)-mediated starvation therapy. And the H2O2 generated in...

Assessment of Pharmacokinetics, Toxicity, and Biodistribution of a High Dose of Titanate Nanotubes Following Intravenous Injection in Mice: A Promising Nanosystem of Medical Interest

Titanate nanotubes (TiNTs) produced by the static hydrothermal process present a promising nanosystem for nanomedicine. However, the behavior of these nanotubes in vivo is not yet clarified. In this work, for the first time, we investigated the toxicity of these materials, their pharmacokinetic profile, and their biodistribution in mice. A high dose of TiNTs (45 mg/kg) was intravenously injected in mice and monitored from 6 h to 45 days. The histological examination of organs and the analysis of liver and kidney function markers and then the inflammatory response were in agreement with a long-term innocuity of these nanomaterials. The parameters of pharmacokinetics revealed the rapid clarification of TiNTs from the bloodstream after 6 h of the intravenous injection which then mainly accumulated in the liver and spleen, and their degradation and clearance in these tissues were relatively slow (>4 weeks). Interestingly, an important property of these materials is their slow dissolution under the lysosome acid environment, rendering them biodegradable. It is noteworthy that TiNTs were directly eliminated in urine and bile ducts without obvious toxicity in mice. Altogether, all these typical in vivo tests studying the TiNT pharmacokinetics, toxicity, and biodistribution are supporting the use of these biocompatible nanomaterials in the biomedical field, especially as a nanocarrier-based drug delivery system.

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.

Targeting nonapoptotic pathways with functionalized nanoparticles for cancer therapy: current and future perspectives

Apoptotic death evasion is a hallmark of cancer progression. In this context, past decades have witnessed cytotoxic agents targeting apoptosis. However, owing to cellular defects in the apoptotic machinery, tumors develop resistance to apoptosis-based cancer therapies. Hence, targeting nonapoptotic cell-death pathways displays enhanced therapeutic success in apoptosis-defective tumor cells. Exploitation of multifunctional properties of engineered nanoparticles may allow cancer therapeutics to target yet unexplored pathways such as ferroptosis, autophagy and necroptosis. Necroptosis presents a programmed necrotic death initiated by same apoptotic death signals that are caspase independent, whereas autophagy is self-degradative causing vacuolation, and ferroptosis is an iron-dependent form driven by lipid peroxidation. Targeting these tightly regulated nonapoptotic pathways may emerge as a new direction in cancer drug development, diagnostics and novel cancer nanotherapeutics. This review highlights the current challenges along with the advancement in this field of research and finally summarizes the future perspective in terms of their clinical merits.

Differential regulation of autophagy by STAU1 in alveolar rhabdomyosarcoma and non-transformed skeletal muscle cells

PURPOSE

Recent work has highlighted the therapeutic potential of targeting autophagy to modulate cell survival in a variety of diseases including cancer. Recently, we found that the RNA-binding protein Staufen1 (STAU1) is highly expressed in alveolar rhabdomyosarcoma (ARMS) and that this abnormal expression promotes tumorigenesis. Here, we asked whether STAU1 is involved in the regulation of autophagy in ARMS cells.

METHODS

We assessed the impact of STAU1 expression modulation in ARMS cell lines (RH30 and RH41), non-transformed skeletal muscle cells (C2C12) and STAU1-transgenic mice using complementary techniques.

RESULTS

We found that STAU1 silencing reduces autophagy in the ARMS cell lines RH30 and RH41, while increasing their apoptosis. Mechanistically, this inhibitory effect was found to be caused by a direct negative impact of STAU1 depletion on the stability of Beclin-1 (BECN1) and ATG16L1 mRNAs, as well as by an indirect inhibition of JNK signaling via increased expression of Dual specificity phosphatase 8 (DUSP8). Pharmacological activation of JNK or expression silencing of DUSP8 was sufficient to restore autophagy in STAU1-depleted cells. By contrast, we found that STAU1 downregulation in non-transformed skeletal muscle cells activates autophagy in a mTOR-dependent manner, without promoting apoptosis. A similar effect was observed in skeletal muscles obtained from STAU1-overexpressing transgenic mice.

CONCLUSIONS

Together, our data indicate an effect of STAU1 on autophagy regulation in ARMS cells and its differential role in non-transformed skeletal muscle cells. Our findings suggest a cancer-specific potential of targeting STAU1 for the treatment of ARMS.

Polymer-lipid hybrid nanovesicle-enabled combination of immunogenic chemotherapy and RNAi-mediated PD-L1 knockdown elicits antitumor immunity against melanoma

Immunotherapy has revolutionized cancer treatment; however, only a limited portion of patients show responses to currently available immunotherapy regimens. Here, we demonstrate that RNA interference (RNAi) combined with immunogenic chemotherapy can elicit potent antitumor immunity against melanoma. Specially, we developed cationic polymer-lipid hybrid nanovesicles (P/LNVs) as a new delivery system for doxorubicin and small interfering RNA (siRNA) with extensive cytotoxicity and gene silencing efficiency towards B16 cells. The deployment of doxorubicin-loaded P/LNVs augmented the expression and presentation of endogenous tumor antigens directly in situ by inducing the immunogenic cell death of B16 cells through poly(ADP-ribose) polymerase 1-dependent (PARP1) apoptosis pathway; thereby, eliciting remarkable antitumor immune responses in mice. Leveraging dying B16 cells as a vaccination strategy in combination with RNAi-based programmed cell death ligand 1 (PD-L1) knockdown showed efficacy in both prophylactic and metastasis melanoma settings. Strikingly, PD-L1 blockade synergized with a sub-therapeutic dose of doxorubicin triggered robust therapeutic antitumor T-cell responses and eradicated pre-established tumors in 30% of mice bearing B16 melanoma. Our findings indicated that this combination treatment provided a new powerful immunotherapy modality, characterized by markedly increased infiltration of effector CD8⁺ T cells and effective alleviation of the immunosuppressive microenvironment in tumors. P/LNVs is a versatile and highly scalable carrier that can enable a broad combination of nanomedicine and RNAi, providing new therapeutic strategies for advanced cancers.

Two-dimensional materials in biomedical, biosensing and sensing applications

Two-dimensional (2D) materials are at the forefront of materials research. Here we overview their applications beyond graphene, such as transition metal dichalcogenides, monoelemental Xenes (including phosphorene and bismuthene), carbon nitrides, boron nitrides along with transition metal carbides and nitrides (MXenes). We discuss their usage in various biomedical and environmental monitoring applications, from biosensors to therapeutic treatment agents, their toxicity and their utility in chemical sensing. We highlight how a specific chemical, physical and optical property of 2D materials can influence the performance of bio/sensing, improve drug delivery and photo/thermal therapy as well as affect their toxicity. Such properties are determined by crystal phases electrical conductivity, degree of exfoliation, surface functionalization, strong photoluminescence, strong optical absorption in the near-infrared range and high photothermal conversion efficiency. This review conveys the great future of all the families of 2D materials, especially with the expanding 2D materials' landscape as new materials emerge such as germanene and silicene.

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.

Doxorubicin-loaded pH-responsive nanoparticles coated with chlorin e6 for drug delivery and synergetic chemo-photodynamic therapy

The integration of chemotherapy drugs and photosensitizers to form versatile nanoplatforms for achieving chemo-photodynamic synergetic therapy has shown great superiority in tumor theranostic applications. We constructed pH-responsive nanoparticles (DOX/PB NPs) encapsulating the chemotherapeutic drug doxorubicin (DOX) into the cores of PLGA NPs coated with bovine serum albumin (BSA) via a water-in-oil (W/O/W) emulsion method. A simple and efficient chemo-photodynamic synergetic nanoplatform (DOX/PB@Ce6 NPs) was obtained by the adsorption of photosensitizer chlorin e6 (Ce6) onto the surface of the DOX/PB NPs. With optimal size, pH-responsive drug release behavior and excellent singlet oxygen production, the DOX/PB@Ce6 NPs have the potential to enhance anti-tumor efficiency. The cellular uptake, cytotoxicity, chemo-photodynamic synergetic effect and biocompatibility of the NPs were evaluated based on HeLa cells via in vitro experiments. The in vitro chemo-photodynamic synergetic experiments indicated that the DOX/PB@Ce6 NPs had remarkable cancer cell killing efficiency under laser irradiation. Notably, by hemolysis assay, all the NPs displayed excellent blood compatibility and were expected to be applicable for intravenous injection. In summary, the designed DOX/PB@Ce6 NPs multifunctional theranostic nanoplatform had excellent reactive oxygen species generation and would be a potential therapeutic platform for chemo-photodynamic synergetic therapy.

Role of JNK Signaling Pathway in Dexmedetomidine Post-Conditioning-Induced Reduction of the Inflammatory Response and Autophagy Effect of Focal Cerebral Ischemia Reperfusion Injury in Rats

To investigate the effect of dexmedetomidine post-conditioning on the inflammatory response and autophagy effect of focal cerebral ischemia reperfusion injury in rats, and further to study its potential mechanisms. Water maze was conducted to evaluate spatial learning and memory ability of middle cerebral artery occlusion (MCAO) rats. TTC staining was used to observe the area of cerebral infarction. The expressions of inflammatory factors in serum were detected by ELISA. TUNEL assay, HE staining, and transmission electron microscopy were used to detect the apoptosis of neurons, neuro-cytopathic changes, and the formation of auto-phagosome in hippocampus CA1 region, respectively. The mRNA and protein expression of Beclin-1, Caspase-3, and light chain 3 (LC3) were detected by qRT-PCR and Western blot. Moreover, the activity of C-Jun N-terminal kinase (JNK) pathway was detected by Western blot. The escape latency (EL); cerebral infarction area ratio; positive apoptosis; neuron pathological changes; auto-phagosome numbers; inflammatory factor contents; mRNA and protein expressions of Beclin-1, Caspase-3 and LC3II/I; and the phosphorylation level of JNK were decreased, while the times across platform and the times stayed in the quadrant of the original platform were increased after dexmedetomidine treatment. However, the protective effect of dexmedetomidine on brain injury in MCAO rats was reversed by JNK pathway activator. Dexmedetomidine post-conditioning could improve learning and memory dysfunction caused by MCAO in rats and reduce the inflammatory response and autophagy effect. The mechanism may be related to inhibition of JNK pathway activation.

Autophagy inhibition changes the disposition of non-viral gene carriers during blood-brain barrier penetration and enhances TRAIL-induced apoptosis in brain metastatic tumor

Non-viral gene delivery systems have proven to be a promising approach in the treatment of brain metastatic cancers but facing delivery difficulties. Due to the existence of blood-brain barrier, non-viral gene carriers must pass through brain capillary endothelial cells to accumulate at the brain tumor sites. However, during this process, most of them trap into brain capillary endothelial cells and fail to penetrate to the brain tumor sites. Autophagy is involved in dynamic disposition of both intracellular and extracellular components, which theoretically affects intracellular fate of non-viral gene carriers during BBB penetration. In the present study, R6dGR peptide-modified PEGylated polyethyleneimine that carry therapeutic gene encoding human tumor necrosis factor-related apoptosis-inducing ligand (PPR/pTRAIL) are established as model non-viral gene delivery system and applied in breast cancer brain metastasis therapy. Autophagy-mediated lysosome degradation pathway is found to be involved in the degradation of PPR/pTRAIL in brain capillary endothelial cells and prevents them from BBB penetration. Pre-inhibiting BBB autophagy level by wortmannin loaded liposomes (Wtmn-Lip) can increase brain accumulation of non-viral gene carrier PPR without damaging BBB tight junctions. Besides, Wtmn-Lip synergistically induces apoptosis with TRAIL via different signaling pathways. Herein, pre-treatment of Wtmn-Lip might solve delivery difficulties of non-viral gene carriers in the treatment of brain metastatic cancers.

Pulmonary-Affinity Paclitaxel Polymer Micelles in Response to Biological Functions of Ambroxol Enhance Therapeutic Effect on Lung Cancer

Purpose

Cancer chemotherapy effect has been largely limited by cell autophagy and little drug accumulation at the action sites. Herein, we designed an intelligent strategy involving paclitaxel (PTX) polymer micelles in response to biological functions of ambroxol (Ax). The amphiphilic polymers polyethyleneglycol-polylactic acid (PEG-PLA) and Pluronic P105 were selected as nanocarriers to encapsulate PTX to form into lung affinity PEG-PLA/P105/PTX micelles. Ax which can up-regulate the secretion of pulmonary surfactant (PS) and inhibit autophagy was hired to change the microenvironment of the lung, thereby promoting the lung accumulation and increasing cell-killing sensitivity of the micelles.

Methods

The physical and chemical properties of the micelles were characterized including size, morphology, critical micellar concentration (CMC) and in vitro drug release behavior. The therapeutic effects of the combination regimen were characterized both in vitro and in vivo including study on Ax in promoting the secretion of pulmonary surfactant, in vitro cytotoxicity, cellular uptake, Western blotting, in vivo biodistribution, in vivo pharmacokinetics and in vivo antitumor efficacy.

Results

The PEG-PLA/P105/PTX micelles showed a particle size of 16.7 ± 0.5 nm, a nearly round shape, small CMC and sustained drug release property. Moreover, the in vitro results indicated that Ax could increase PS and LC3 protein secretion and enhance the cytotoxicity of PEG-PLA/P105/PTX micelles toward A549 cells. The in vivo results indicated that the combination therapeutic regimen could promote the micelles to distribute in lung and enhance the therapeutic effect on lung cancer.

Conclusion

This multifunctional approach of modulating the tumor microenvironment to enhance drug transportation and cell-killing sensitivity in the action sites might offer a new avenue for effective lung cancer treatment.

Drug Delivery with Polymeric Nanocarriers-Cellular Uptake Mechanisms

Nanocarrier-based systems hold a promise to become “Dr. Ehrlich’s Magic Bullet” capable of delivering drugs, proteins and genetic materials intact to a specific location in an organism down to subcellular level. The key question, however, how a nanocarrier is internalized by cells and how its intracellular trafficking and the fate in the cell can be controlled remains yet to be answered. In this review we survey drug delivery systems based on various polymeric nanocarriers, their uptake mechanisms, as well as the experimental techniques and common pathway inhibitors applied for internalization studies. While energy-dependent endocytosis is observed as the main uptake pathway, the integrity of a drug-loaded nanocarrier upon its internalization appears to be a seldomly addressed problem that can drastically affect the uptake kinetics and toxicity of the system in vitro and in vivo.

Duo of (-)-epigallocatechin-3-gallate and doxorubicin loaded by polydopamine coating ZIF-8 in the regulation of autophagy for chemo-photothermal synergistic therapy

To achieve highly systemic therapeutic efficacy, chemotherapy is combined with photothermal therapy for chemo-photothermal synergistic therapy; however, this strategy suffers from high toxicity and unsatisfactory sensitivity for cancer cells. Herein, we developed a pH- and photothermal-responsive zeolitic imidazolate framework (ZIF-8) compound for loading a dual-drug in the tumor site and improving their curative effects. Since autophagy always accompanies tumor progression and metastasis, there is an unmet need for an anticancer treatment related to the regulation of autophagy. Green tea polyphenols, namely, (-)-epigallocatechin-3-gallate (EGCG) and doxorubicin (DOX), both of which exhibit anticancer activity, were dual-loaded via polydopamine (PDA) coating ZIF-8 (EGCG@ZIF-PDA-PEG-DOX, EZPPD for short) through hierarchical self-assembly. PDA could transfer photothermal energy to increase the temperature under near-infrared (NIR) laser irradiation. Due to its pH-response, EZPPD released EGCG and DOX in the tumor microenvironment, wherein the temperature increased with the help of PDA and NIR laser irradiation. The duo of DOX and EGCG induced autophagic flux and accelerated the formation of autophagosomes. In a mouse HeLa tumor model, photothermal-chemotherapy could ablate the tumor with a significant synergistic effect and potentiate the anticancer efficacy. Thus, the results indicate that EZPPD renders the key traits of a clinically promising candidate to address the challenges associated with synergistic chemotherapy and photothermal utilization in antitumor therapy.

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.

Overcoming Physiological Barriers to Nanoparticle Delivery-Are We There Yet?

The exploitation of nanosized materials for the delivery of therapeutic agents is already a clinical reality and still holds unrealized potential for the treatment of a variety of diseases. This review discusses physiological barriers a nanocarrier must overcome in order to reach its target, with an emphasis on cancer nanomedicine. Stages of delivery include residence in the blood stream, passive accumulation by virtue of the enhanced permeability and retention effect, diffusion within the tumor lesion, cellular uptake, and arrival at the site of action. We also briefly outline strategies for engineering nanoparticles to more efficiently overcome these challenges: Increasing circulation half-life by shielding with hydrophilic polymers, such as PEG, the limitations of PEG and potential alternatives, targeting and controlled activation approaches. Future developments in these areas will allow us to harness the full potential of nanomedicine.

High-effective reactive oxygen species inducer based on Mn-tetraphenylporphyrin loaded PLGA nanoparticles in binary catalyst therapy

The mechanisms of binary catalyst therapy (BCT) and photodynamic therapy (PDT) are based on the formation of reactive oxygen species (ROS). This ROS formation results from specific chemical reactions. In BCT, light exposure does not necessarily initiate ROS formation and BCT application is not limited to regions of tissues that are accessible to illumination like photodynamic therapy (PDT). The principle of BCT is electron transition, resulting in the interaction of a transition metal complex (catalyst) and substrate molecule. Mn^III- tetraphenylporphyrin chloride (MnClTPP) in combination with an ascorbic acid (AA) has been proposed as an appropriate candidate for cancer treatment regarding the active agents in BCT. The goal of this study was to determine whether MnClTPP in combination with AA would be a promising agent for BCT. The problem of used MnClTPP's, low solubility in water, was solved by MnClTPP loading into PLGA matrix. H₂O₂ produced during AA decomposition oxidized MnClTPP to high-reactive oxo-Mn^V species. MnClTPP in presence AA leads to the production of excessive ROS levels in vitro. ROS are mainly substrates of catalase and superoxide dismutase (H₂O₂ and O₂^●-). SOD1 and catalase were identified as the key players of the MnClTPP ROS-induced cell defense system. The cytotoxicity of MnClTPP-loaded nanoparticles (NPs) was greatly increased in the presence of specific catalase inhibitor (3-amino-1,2,4-triazole (3AT)) and superoxide dismutase 1 (SOD1) inhibitor (diethyldithiocarbamate (DDC)). Cell death resulted from the combined activation of caspase-dependent (caspase 3/9 system) and independent pathways, namely the AIF translocation to nuclei. Preliminary acute toxicity and in vivo anticancer studies have been revealed the safe and potent anticancer effect of PLGA-entrapped MnClTPP in combination with AA. The findings indicate that MnClTPP-loaded PLGA NPs are promising agents for BCT.

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.

Drug Nanorod-Mediated Intracellular Delivery of microRNA-101 for Self-sensitization via Autophagy Inhibition

Autophagy is closely related to the drug resistance and metastasis in cancer therapy. Nanoparticle-mediated co-delivery of combinatorial therapy with small-molecular drugs and nucleic acids is promising to address drug resistance. Here, a drug-delivering-drug (DDD) platform consisting of anti-tumor-drug nanorods as a vehicle for cytosol delivery of nucleic acid (miR-101) with potent autophagic-inhibition activity is reported for combinatorial therapy. The developed 180-nm nanoplatform, with total drug loading of up to 66%, delivers miR-101 to cancer cells, with threefold increase in intracellular level compared to conventional gene carriers and inhibits the autophagy significantly, along with above twofold reduction in LC3II mRNA and approximately fivefold increase in p62 mRNA over the control demonstrated in the results in vivo. And in turn, the delivery of miR-101 potentiates the drug's ability to kill cancer cells, with a threefold increase in apoptosis over that of chemotherapy alone. The anti-tumor study in vivo indicates the combined therapy that enables a reduction of 80% in tumor volume and > twofold increase in apoptosis than of the single-drug strategy. In summary, via the carrier-free strategy of DDD, this work provides a delivery platform that can be easily customized to overcome drug resistance and facilitates the delivery of combined therapy of small-molecular drugs and nucleic acids.

Autophagy Modulators: Mechanistic Aspects and Drug Delivery Systems

Autophagy modulation is considered to be a promising programmed cell death mechanism to prevent and cure a great number of disorders and diseases. The crucial step in designing an effective therapeutic approach is to understand the correct and accurate causes of diseases and to understand whether autophagy plays a cytoprotective or cytotoxic/cytostatic role in the progression and prevention of disease. This knowledge will help scientists find approaches to manipulate tumor and pathologic cells in order to enhance cellular sensitivity to therapeutics and treat them. Although some conventional therapeutics suffer from poor solubility, bioavailability and controlled release mechanisms, it appears that novel nanoplatforms overcome these obstacles and have led to the design of a theranostic-controlled drug release system with high solubility and active targeting and stimuli-responsive potentials. In this review, we discuss autophagy modulators-related signaling pathways and some of the drug delivery strategies that have been applied to the field of therapeutic application of autophagy modulators. Moreover, we describe how therapeutics will target various steps of the autophagic machinery. Furthermore, nano drug delivery platforms for autophagy targeting and co-delivery of autophagy modulators with chemotherapeutics/siRNA, are also discussed.

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.

Boosting Cancer Therapy with Organelle-Targeted Nanomaterials

The ultimate goal of cancer therapy is to eliminate malignant tumors while causing no damage to normal tissues. In the past decades, numerous nanoagents have been employed for cancer treatment because of their unique properties over traditional molecular drugs. However, lack of selectivity and unwanted therapeutic outcomes have severely limited the therapeutic index of traditional nanodrugs. Recently, a series of nanomaterials that can accumulate in specific organelles (nucleus, mitochondrion, endoplasmic reticulum, lysosome, Golgi apparatus) within cancer cells have received increasing interest. These rationally designed nanoagents can either directly destroy the subcellular structures or effectively deliver drugs into the proper targets, which can further activate certain cell death pathways, enabling them to boost the therapeutic efficiency, lower drug dosage, reduce side effects, avoid multidrug resistance, and prevent recurrence. In this Review, the design principles, targeting strategies, therapeutic mechanisms, current challenges, and potential future directions of organelle-targeted nanomaterials will be introduced.

GLUT1-mediated effective anti-miRNA21 pompon for cancer therapy

Oncogenic microRNAs are essential components in regulating the gene expression of cancer cells. Especially miR21, which is a major player involved of tumor initiation, progression, invasion and metastasis in several cancers. The delivery of anti-miR21 sequences has significant potential for cancer treatment. Nevertheless, since anti-miR21 sequences are extremely unstable and they need to obtain certain concentration to function, it is intensely difficult to build an effective delivery system for them. The purpose of this work is to construct a self-assembled glutathione (GSH)-responsive system with tumor accumulation capacity for effective anti-miR21 delivery and cancer therapy. A novel drug delivery nanosphere carrying millions of anti-miR21 sequences was developed through the rolling circle transcription (RCT) method. GSH-responsive cationic polymer polyethyleneimine (pOEI) was synthesized to protect the nanosphere from degradation by Dicer or other RNase in normal cells and optimize the pompon-like nanoparticle to suitable size. Dehydroascorbic acid (DHA), a targeting molecule, which is a substrate of glucose transporter 1 (GLUT 1) and highly expressed on malignant tumor cells, was connected to pOEI through PEG, and then the polymer was used for contracting a RNA nanospheres into nanopompons. The anti-miR21 nanopompons showed its potential for effective cancer therapy.

Degradable Nanoparticles Restore Lysosomal pH and Autophagic Flux in Lipotoxic Pancreatic Beta Cells

Chronic exposure to high levels of fatty acids (lipotoxicity) in pancreatic beta cells (β-cells) decreases lysosomal acidity and inhibits autophagic flux. Today, there are a lack of approaches to modify lysosomal acidity to determine whether impaired lysosomal acidification is causally inhibiting autophagic flux and cellular functions. Biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) with diameters of ≈100 nm localize to lysosomes and serve as an ideal method to deliver lactic and glycolic acid to lysosomes upon NP polymer degradation. In this study, the ability of PLGA NPs to lower lysosomal pH and restore autophagic flux is investigated in pancreatic insulin secreting (INS1) β-cells. PLGA NPs display a concentration dependent performance with higher concentrations of PLGA NPs, lowering lysosomal pH, as well as restoring autophagic flux and insulin secretion in pancreatic β-cells. These results document that acidifying the lysosome, via an external perturbation, in lipotoxic pancreatic β-cells affords a specific biological outcome of improved cellular degradative activity.

Self-Assembled Benznidazole-Loaded Cationic Nanoparticles Containing Cholesterol/Sialic Acid: Physicochemical Properties, In Vitro Drug Release and In Vitro Anticancer Efficacy

Cationic polymeric nanoparticles (NPs) have the ability to overcome biological membranes, leading to improved efficacy of anticancer drugs. The modulation of the particle-cell interaction is desired to control this effect and avoid toxicity to normal cells. In this study, we explored the surface functionalization of cationic polymethylmethacrylate (PMMA) NPs with two natural compounds, sialic acid (SA) and cholesterol (Chol). The performance of benznidazole (BNZ) was assessed in vitro in the normal renal cell line (HEK-293) and three human cancer cell lines, as follows: human colorectal cancer (HT-29), human cervical carcinoma (HeLa), and human hepatocyte carcinoma (HepG2). The structural properties and feasibility of NPs were evaluated and the changes induced by SA and Chol were determined by using multiple analytical approaches. Small (<200 nm) spherical NPs, with a narrow size distribution and high drug-loading efficiency were prepared by using a simple and reproducible emulsification solvent evaporation method. The drug interactions in the different self-assembled NPs were assessed by using Fourier transform-infrared spectroscopy. All formulations exhibited a slow drug-release profile and physical stability for more than 6 weeks. Both SA and Chol changed the kinetic properties of NPs and the anticancer efficacy. The feasibility and potential of SA/Chol-functionalized NPs has been demonstrated in vitro in the HEK-293, HepG2, HeLa, and HT-29 cell lines as a promising system for the delivery of BNZ.

Size-adjustable micelles co-loaded with a chemotherapeutic agent and an autophagy inhibitor for enhancing cancer treatment via increased tumor retention

Autophagy plays a key role in the stress response of tumor cells, which contributes to cancer cell survival and resistance to chemotherapy by degrading cytoplasmic proteins to provide energy and clear the hazardous substances. Therefore, combined treatment of chemotherapeutics and autophagy inhibitors is thought to obtain a desirable antitumor effect. Nanoparticles (NPs) show potential in tumor-targeting drug delivery because of the enhanced permeability and retention (EPR) effect. However, NPs with fixed particle size cannot achieve optimal delivery effect. Herein, a strategy based on Cu (I)-catalyzed click chemistry-triggered aggregation of azide/alkyne-modified micelles was developed for the co-delivery of the chemotherapeutic drug doxorubicin (Dox) and the autophagy inhibitor wortmannin (Wtmn). In vitro experiments showed that the size of micelles increased in a time-dependent manner, which enhanced micelle accumulation in both B16F10 and 4 T1 cells. The fluorescence resonance energy transfer (FRET) experiment and biodistribution study further demonstrated that the aggregation of micelles through click cycloaddition significantly improved the accumulation of drug-loading micelles at the tumor region. Furthermore, the decreased amount of autophagosomes observed by transmission electron microscopy (TEM), the declined expression of LC3-II, and the increased level of p62 by western blotting and immunohistochemistry (IHC) confirmed the obvious inhibition of autophagy induced by Dox/Wtmn co-loaded size-adjustable micelles, which had a synergistic effect in cancer suppression. In addition, the co-loaded size-adjustable micelles showed outstanding cytotoxicity and antitumor effect. Therefore, this strategy effectively suppressed melanoma and breast cancer in mice. STATEMENT OF SIGNIFICANCE: The therapeutic effects of chemotherapy can be limited by autophagy; hence, combined use of autophagy inhibitors with chemotherapeutics achieves desirable anticancer efficacy. In the present study, we designed size-adjustable micelles by modifying the click reaction substrate azide group and the alkyne group on the surface of micelles, and subsequently, the autophagy inhibitor wortmannin and the chemotherapeutic drug doxorubicin were co-loaded. The micelles could aggregate by click reaction at the tumor site when the catalysts were intratumorally injected. The results showed that the size-adjustable micelles achieved efficient drug delivery, penetration, and retention in tumors; through the combined effect of wortmannin-mediated autophagy inhibition and doxorubicin-mediated cytotoxicity, this strategy exerted significant anticancer effect in melanoma and breast cancer treatment.

Co-delivery nanoparticles of doxorubicin and chloroquine for improving the anti-cancer effect in vitro

To increase the efficacy of small molecule chemotherapeutic drug (SMCD) and reduce its toxic and side effects, we selected two model drugs doxorubicin (DOX) and chloroquine (CQ). DOX is a SMCD and CQis a chemosensitizer with autophagy inhibition. Poly(lactic-co-glycolic acid) (PLGA) and alpha-tocopherol polyethylene glycol 1000 succinate were chosen as delivery carriers to design and prepare a novel type of drug co-delivery single-nanoparticles by emulsification-solvent volatilisation, named NP_DOX+CQ. The physicochemical properties of NP_DOX+CQ were characterised. Then A549 cells and A549/Taxol cells were used for the in vitro anti-cancer effect study. At the same time, cellular uptake, intracellular migration and anti-cancer mechanism of nanoparticles were studied. The NPs showed a uniform spherical shape with good dispersibility, and both drugs had good encapsulation efficiency and loading capacity. In all formulations, NP_DOX+CQ showed the highest in vitro cytotoxicity. The results showed that NPs could protect drugs from being recognised and excluded by P-glycoprotein (P-gp). Moreover, the results of the mechanistic study demonstrated that NPs were transported by autophagy process after being taken up by the cells. Therefore, during the migration of NP_DOX+CQ, CQ could exert its efficacy and block autophagy so that DOX would not be hit by autophagy. Western Blot results showed that NP_DOX+CQ had the best inhibition effect of autophagy. It can be concluded that the system can prevent the drug from being recognised and excluded by P-gp, and CQ blocks the process of autophagy so that the DOX is protected and more distributed to the nucleus of multidrug resistance (MDR) cell. The NP_DOX+CQ constructed in this study provides a feasible strategy for reversing MDR in tumour cells.