Rapamycin encapsulated in dual-responsive micelles for cancer therapy

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.

A potential strategy for bladder cancer treatment: inhibiting autophagy to enhance antitumor effects of Nectin-4-MMAE

Research and development on Nectin-4 antibody-drug conjugates (ADC) have been greatly accelerated since the approval of enfortumab vedotin to treat uroepithelial cancer. During the course of this study, we identified that autophagy serves as a cytoprotective mechanism during Nectin-4-MMAE treatment and proposed a strategy to enhance the antitumor effects of Nectin-4-MMAE in bladder cancer. Nectin-4-MMAE rapidly internalized into bladder cancer cells in 30 minutes and released MMAE, inducing the onset of caspase-mediated apoptosis and leading to the inhibition of tumor cell growth. Transcriptomics showed significant alterations in autophagy-associated genes in bladder cancer cells treated with Nectin-4-MMAE, which suggested autophagy was activated by Nectin-4-MMAE. Furthermore, autophagy activation was characterized by ultrastructural analysis of autophagosome accumulation, immunofluorescence of autophagic flux, and immunoblotting autophagy marker proteins SQSTM1 and LC3 I/II. Importantly, inhibiting autophagy by LY294002 and chloroquine significantly enhances the cytotoxicity effects of Nectin-4-MMAE in bladder cancer cells. Additionally, we detected the participation of the AKT/mTOR signaling cascade in the induction of autophagy by Nectin-4-MMAE. The combination of Nectin-4-MMAE and an autophagy inhibitor demonstrated enhanced antitumor effects in the HT1376 xenograft tumor model. After receiving a single dose of Nectin-4-MMAE, the group that received the combination treatment showed a significant decrease in tumor size compared to the group that received only one type of treatment. Notably, one mouse in the combination treatment group achieved complete remission of the tumor. The combination group exhibited a notable rise in apoptosis and necrosis, as indicated by H&E staining and immunohistochemistry (cleaved caspase-3, ki67). These findings demonstrated the cytoprotective role of autophagy during Nectin-4-MMAE treatment and highlighted the potential of combining Nectin-4-MMAE with autophagy inhibitors for bladder cancer treatment.

Novel PEGylated cholephytosomes for targeting fisetin to breast cancer: in vitro appraisal and in vivo antitumoral studies

Fisetin (FIS) is a multifunctional bioactive flavanol that has been recently exploited as anticancer drug against various cancers including breast cancer. However, its poor aqueous solubility has constrained its clinical application. In the current work, fisetin is complexed for the first time with soy phosphatidylcholine in the presence of cholesterol to form a novel biocompatible phytosomal system entitled "cholephytosomes." To improve fisetin antitumor activity against breast cancer, stearylamine bearing cationic cholephytosomes (mPHY) were prepared and furtherly modified with hyaluronic acid (HPHY) to allow their orientation to cancer cells through their surface exposed phosphatidylserine and CD-44 receptors, respectively. In vitro characterization studies revealed promising physicochemical properties of both modified vesicles (mPHY and HPHY) including excellent FIS complexation efficiency (˷100%), improved octanol/water solubility along with a sustained drug release over 24 h. In vitro cell line studies against MDA-MB-231 cell line showed about 10- and 3.5-fold inhibition in IC50 of modified vesicles compared with free drug and conventional drug-phospholipid complex, respectively. Preclinical studies revealed that both modified cholephytosomes (mPHY and HPHY) had comparable cytotoxicity that is significantly surpassing free drug cytotoxicity. TGF-β1and its non-canonical related signaling pathway; ERK1/2, NF-κB, and MMP-9 were involved in halting tumorigenesis. Thus, tailoring novel phytosomal nanosystems for FIS could open opportunity for its clinical utility against cancer.

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.

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.

Self-assembled fisetin-phospholipid complex: Fisetin-integrated phytosomes for effective delivery to breast cancer

Nowadays, fisetin (FIS) is extensively studied as potent anticancer surrogate with a multitarget actions against various types of cancers including breast cancer. However, its poor aqueous solubility handicapped its clinical utility. The current work endeavored, for the first time, to develop FIS phytosomes (FIS-PHY) for improving its physicochemical properties and subsequently its anticancer activity. Optimization of FIS- phytosomes involved different preparation techniques (Thin film hydration and ethanol injection) and different FIS: phospholipid molar ratios (1:1, 1:2, and 1:3). Complex formation was confirmed by complexation efficiency, infrared spectroscopy (IR), solubility studies and transmission electron microscope. The optimized FIS-PHY of 1:1 M ratio (PHY1) exhibited a nanometric particle size of 233.01 ± 9.46 nm with homogenous distribution (PDI = 0.27), negative zeta potential of - 29.41 mV, 100% complexation efficiency and controlled drug release over 24 h. In-vitro cytotoxicity study showed 2.5-fold decrease in IC50 of PHY1 compared with free FIS. Also, pharmacodynamic studies confirmed the promoted cytotoxicity of PHY1 against breast cancer through modulating TGF-β1/MMP-9 molecular pathways of tumorigenesis. Overall, overcoming FIS drawbacks were successfully achieved through development of innovative biocompatible phytosomal system.

Geraniol suppresses tumour growth and enhances chemosensitivity of 5-fluorouracil on breast carcinoma in mice: involvement of miR-21/PTEN signalling

OBJECTIVES

Breast cancer is the most diagnosed cancer in females worldwide. Phytochemicals are among the recent compelling approaches showing anticancer activity. Geraniol is a monoterpenoid showing anti-tumoral potential in cell lines. However, its exact mechanism in breast cancer has not been elucidated. In addition, the possible chemosenstizing effect of geraniol when combined with chemotherapeutic drugs in breast carcinoma has not been previously addressed.

METHODS

Therefore, the aim of the current work is to investigate the potential therapeutic as well as chemosensitizing effects of geraniol on breast carcinoma induced in mice through examination of tumour biomarkers and histopathology profile.

KEY FINDINGS

Results showed a prominent suppression of tumour growth following geraniol treatment. This was accompanied with miR-21 downregulation that subsequently upregulated PTEN and suppressed mTOR levels. Geraniol was also able to activate apoptosis and inhibit autophagy. Histopathological examination revealed high necrosis areas separating malignant cells in the geraniol-treated group. Combined geraniol and 5-fluorouracil treatment induced more than 82% inhibition of tumour rate, surpassing the effect of each drug alone.

CONCLUSIONS

It can be concluded that geraniol could represent a promising avenue for breast cancer treatment as well as a potential sensitizing agent when combined with chemotherapeutic drugs.

Autophagy-Associated Immunogenic Modulation and Its Applications in Cancer Therapy

Autophagy, a lysosome-mediated cellular degradation pathway, recycles intracellular components to maintain metabolic balance and survival. Autophagy plays an important role in tumor immunotherapy as a “double-edged sword” that can both promote and inhibit tumor progression. Autophagy acts on innate and adaptive immunity and interacts with immune cells to modulate tumor immunotherapy. The discovery of autophagy inducers and autophagy inhibitors also provides new insights for clinical anti-tumor therapy. However, there are also difficulties in the application of autophagy-related regulators, such as low bioavailability and the lack of efficient selectivity. This review focuses on autophagy-related immunogenic regulation and its application in cancer therapy.

Doxorubicin-Loaded Mixed Micelles Using Degradable Graft and Diblock Copolymers to Enhance Anticancer Sensitivity

Simple Summary

In this study, a long-circulating and pH responsive mixed micellar system was assembled with a degradable graft copolymer, poly(N-(2-hydroxypropyl) methacrylamide dilactate)-co-(N-(2-hydroxypropyl) methacrylamide-co-histidine)-graft-poly(d,l-lactide), and a diblock copolymer, methoxy poly(ethylene glycol)-b-poly(d,l-lactide) to load with the anticancer agent doxorubicin. The in vitro results indicate that the micellar system display high biosafety and intracellular drug-releasing behavior in cancer cells. Furthermore, the in vivo results show that the high stability of the mixed micelles leads to a high tumor accumulation and hence an excellent inhibition of tumor growth. This mixed micellar system, comprising degradable diblock and graft copolymers enables one to increase cancer cells’ sensitivity toward doxorubicin (Dox) and is feasible for further clinical use in cancer therapy.

Abstract

In this study, a graft copolymer, poly(N-(2-hydroxypropyl) methacrylamide dilactate)-co-(N-(2-hydroxypropyl) methacrylamide-co-histidine)-graft-poly(d,l-lactide), and a diblock copolymer, methoxy poly(ethylene glycol)-b-poly(d,l-lactide), were assembled into a mixed micellar system to encapsulate the anticancer drug doxorubicin (Dox). This mixed micellar system possesses the hydrophobic lactide segment of both copolymers, which reinforces its stability in physiological milieus; the histidine molecules appended on the graft copolymer provide the desired pH-responsive behavior to release Dox during internalization in cancer cells. The results demonstrate that the two copolymers were successfully prepared, and their ratios in the mixed micelles were optimized on the basis of the results of the stability tests. Under acidic conditions, the mixed micelles swell and are able to release their payloads. Therefore, the in vitro results indicate that the Dox in the mixed micelles is released effectively in response to the environmental pH of the mimetic internalization process, increasing cancer cells’ sensitivity toward Dox. The mixed micelles display low cytotoxicity due to the degradability of the polymers. The in vivo images show that the high stability of the mixed micelles ensures a high tumor accumulation. This selective tumor accumulation results in an excellent inhibition of in vivo tumor growth and a high rate of apoptosis in cancerous tissues, with low toxicity. This highly stable, mixed micellar system with a pH-dependent drug release, which enables the precise delivery of drugs to the tumor lesions, is feasible to employ clinically in cancer therapy.

Rapamycin as a "One-Stone-Three-Birds" Agent for Cooperatively Enhanced Phototherapies Against Metastatic Breast Cancer

Cooperative photothermal therapy (PTT) and photodynamic therapy (PDT) represents a promising strategy to conquer tumor with synergistic effect, while their long-term efficacy has been strictly limited by the multiple resistances of tumor. Here, we reported a core-shell nanoplatform for enhanced PTT/PDT combination against metastatic breast cancer. The nanosystem had photosensitizer chlorin e6 (Ce6) and rapamycin (RAP) pure drugs core and the polydopamine (PDA) shell, with surface PEGylation. Notably, we found that RAP was a highly robust sensitizer to boost the efficacy of both PTT and PDT by inhibiting the expression of heat shock protein 70 (HSP 70) and hypoxia inducible factor-1α (HIF-1α), respectively, resulting in cooperatively enhanced antitumor efficiency. Moreover, metastasis, the fatal risk of breast cancer, was also inhibited by virtue of RAP-mediated matrix metalloproteinases-2 (MMP-2) suppression. Upon intravenous injection, the nanosystem could passively accumulate into the tumor and impose potent phototherapies upon dual laser irradiations for complete tumor elimination and metastasis inhibition, giving rise to 100% mice survival over a long observation period. Collectively, this work offers a general solution to address the key limitations of tumor-resistant phototherapies and provides a highly promising nanoplatform for the management of metastatic cancer.

Preclinical autophagy modulatory nanomedicines: big challenges, slow advances

INTRODUCTION

Autophagy is a critical housekeeping pathway to remove toxic protein aggregates, damaged organelles, providing cells with bioenergetic substrates needed to survive under adverse conditions. Since altered autophagy is associated with diverse diseases, its pharmacological modulation is considered of therapeutic interest. Nanomedicines may reduce the toxicity and improve the activity of toxic autophagy modulatory drugs (amd).

AREAS COVERED

The status of the most relevant anti-tumor, anti-inflammatory, and anti-infectious treatments mediated by autophagy modulatory nanomedicines (amN) published in the last 5 years is discussed.

EXPERT OPINION

Antitumor and anti-inflammatory treatments may be improved by administering amN for selective, massive, and targeted delivery of amd to diseased tissues. The use of amN as antimicrobial agent remains almost underexploited. Assessing the effect of amN on the complex autophagy machinery operating under different basal diseases, however, is not a trivial task. Besides structural reproducibility, nanomedicines must grant higher efficiency, and lower adverse effects than conventional medication. Simplicity of design, carefully chosen (scalable) preparation techniques, and rigorous monitoring of preclinical efficacy and nanotoxicity will improve the chances of clinical success. Currently, available data are not sufficient to envisage a fast-succeeding translation. Application of quality by design criteria would help to reach such milestones.

Delivery of Rapamycin by Liposomes Synergistically Enhances the Chemotherapy Effect of 5-Fluorouracil on Colorectal Cancer

Background

Rapamycin is a promising agent for treating tumors, but clinical applications of rapamycin are limited due to its poor water solubility and low bioavailability. This paper constructs a liposome delivery system for rapamycin to improve the effect in treating colorectal cancer.

Methods

We prepared the rapamycin liposomes using the ethanol injection method. The cellular uptake and biodistribution were detected by LC-MS and in vivo imaging system. MTT assay, transwell migration experiment, flow cytometry, and Western blot analysis evaluated the antitumor effect of rapamycin liposomes in vitro. Furthermore, HCT-116 tumor-bearing mice were used to assess the therapeutic efficacy of rapamycin liposomes in vivo.

Results

The prepared rapamycin liposomes had a particle size of 100±5.5 nm and with a narrow size distribution. In vitro cellular uptake experiments showed that the uptake of rapamycin liposomes by colorectal cells was higher than that of free rapamycin. Subsequently, in vivo imaging experiments also demonstrated that rapamycin liposomes exhibited higher tumor accumulation. Therefore, the ability of rapamycin liposomes to inhibit tumor proliferation, migration and to induce tumor apoptosis is superior to that of free rapamycin. We also demonstrated in vivo good antitumor efficacy of the rapamycin liposomes in HCT-116 xenograft mice. In addition, rapamycin liposomes and 5-FU can synergistically improve the efficacy of colorectal cancer via the Akt/mTOR and P53 pathways.

Conclusion

Collectively, rapamycin liposomes are a potential treatment for colorectal cancer, as it not only improves rapamycin’s antitumor effect but also synergistically enhances 5-FU’s chemotherapy effect.

Core-Shell Nanosystems for Self-Activated Drug-Gene Combinations against Triple-Negative Breast Cancer

The combination of gene therapy with chemotherapeutics provides an efficacious strategy for enhanced tumor therapy. RNA-cleaving DNAzyme has been recognized as a promising gene-silencing tool, while its combination with chemotherapeutic drugs has been limited by the lack of an effective codelivery system to allow sufficient intracellular DNAzyme activation, which requires specific metal ions as a cofactor. Here, a self-activatable DNAzyme/drug core-shell codelivery system is fabricated to combat triple-negative breast cancer (TNBC). The hydrophobic chemotherapeutic, rapamycin (RAP), is self-assembled into the pure drug nanocore, and the metal-organic framework (MOF) shell based on coordination between Mn²⁺ and tannic acid (TA) is coated on the surface to coload an autophagy-inhibiting DNAzyme. The nanosystem efficiently delivers the payloads into tumor cells, and upon endocytosis, the MOF shell is disintegrated to release the therapeutics in response to an acidic endo/lysosome environment and intracellular glutathione (GSH). Notably, the coreleased Mn²⁺ serves as the cofactor of DNAzyme for effective self-activation, which suppresses the expression of Beclin 1 protein, the key initiator of autophagy, resulting in a significantly strengthened antitumor effect of RAP. Using tumor-bearing mouse models, the nanosystem could passively accumulate into the tumor tissue, impose potent gene-silencing efficacy, and thus sensitize chemotherapy to inhibit tumor growth upon intravenous administration, providing opportunities for combined gene-drug TNBC therapy.

Factors affecting the morphology of some organic and inorganic nanostructures for drug delivery: characterization, modifications, and toxicological perspectives

Introduction: In this review, we aim to highlight the impact of various processes and formulation variables influencing the characteristics of certain surfactant-based nanoconstructs for drug delivery. Areas covered: The review includes the discussion on processing parameters for the preparation of nanoconstructs, especially those made up of surfactants. Articles published in last 15 years (437) were reviewed, 381 articles were selected for data review and most appropriate articles (215) were included in article. Effect of variables such as surfactant concentration and type, membrane additives, temperature, and pH-dependent transitions on morphology has been highlighted along with effect of shape on nanoparticle uptake by cells. Various characterization techniques explored for these nanostructures with respect to size, morphology, lamellarity, distribution, etc., and a separate section on polymeric vesicles and the influence of block copolymers, type of block copolymer, control of block length, interaction of multiple block copolymers on the structure of polymersomes and chimeric nanostructures have been discussed. Finally, applications, modification, degradation, and toxicological aspects of these drug delivery systems have been highlighted. Expert opinion: Parameters influencing the morphology of micelles and vesicles can directly or indirectly affect the efficacy of small molecule cellular internalization as well as uptake in the case of biologicals.[Figure: see text].

Rapamycin-Loaded mPEG-PLGA Nanoparticles Ameliorate Hepatic Steatosis and Liver Injury in Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive lipid accumulation and liver injury, and is the leading cause of chronic liver disease worldwide. There is an urgent need to develop novel pathophysiology-oriented therapy in human. Rapamycin (RAPA) has been recognized as a promising drug for alleviating hepatic steatosis on NAFLD, but the poorly water-soluble properties and side effects of RAPA limit their clinical use. In this study, we aimed to investigate the in vitro and in vivo therapeutic efficacy of biodegradable mPEG-PLGA polymers loaded with RAPA (NP-RAPA) on NAFLD. NP-RAPA were prepared by a green process using an emulsion/solvent evaporation method, the therapeutic efficacy on NAFLD were investigated on HepG2 cells incubated with oleic acid (OA) and in the livers of mice with NAFLD induced by high-fat diet (HFD). Compared with free RAPA, NP-RAPA significantly reduced lipid accumulation in HepG2 cells, and obviously ameliorated hepatic steatosis and liver injury in mice though enhancing the therapeutic efficacy of RAPA through reducing SREBP-1c-dependent de novo lipogenesis (DNL) and promoting PPARα-mediated fatty acid oxidation. This study suggests that mPEG-PLGA can be used as the potential therapeutic strategy and novel drug delivery for improving the efficacy of rapamycin for treatment of NAFLD.

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.

Cancer Therapy Based on Smart Drug Delivery with Advanced Nanoparticles

Background:

Cancer, as one of the most dangerous disease, causes millions of deaths every year. The main reason is the absence of an effective and thorough treatment. Drug delivery systems have significantly reduced the side-effect of chemotherapy. Combined with nanotechnology, smart drug delivery systems including many different nanoparticles can reduce the side-effect of chemotherapy better than traditional drug delivery systems.

Methods:

In this article, we will describe in detail the different kinds of nanoparticles and their mechanisms emphasizing the triggering factors in drug delivery. Besides, the application of smart drug delivery systems in imaging will be introduced.

Results:

Combined with nanotechnology, smart drug delivery systems including many different nanoparticles can reduce the side-effect of chemotherapy better than traditional drug delivery systems.

Conclusion:

Despite considerable progress in nanoparticle research over the past decade, such as smart drug delivery systems for the treatment of cancer, molecular imaging probes and the like. The range of nanoparticles used in multifunction systems for imaging and drug delivery continues to grow and we expect this dilatation to continue. But to make nanoparticles truly a series of clinical products to complement and replace current tools, constant exploration efforts and time are required. Overall, the future looks really bright.

A novel therapeutic approach to colorectal cancer in diabetes: role of metformin and rapamycin

The link between colorectal cancer (CRC), diabetes mellitus (DM) and inflammation is well established, and polytherapy, including rapamycin, has been adopted. This study is a novel approach that aimed at assessing the effect of a combination therapy of metformin and rapamycin on the control or prevention of CRC in diabetic animals, in presence or absence of probiotics. Fifty NOD/SCIDs male mice developed xenograft by inoculating HCT116 cells. They were equally divided into diabetics (induced by Streptozotocin) and non-diabetics. Metformin was given in drinking water, whereas rapamycin was administered via intra-peritoneal injections. Probiotics were added to the double therapy two weeks before the sacrifice. Assessment was performed by clinical observation, histological analysis, Reactive oxygen species (ROS) activities and molecular analysis of Interleukin 3 and 6, Tumor Necrosis Factor alpha, AMP-activated protein Kinase and the mammalian target of rapamycin. Decreases in the level of tumorigenesis resulted, to various extents, with the different treatment regimens. The combination of rapamycin and metformin had no significant result, however, after adding probiotics to the combination, there was a marked delay in tumor formation and reduction of its size, suppression of ROS and a decrease in inflammatory cytokines as well as an inhibition of phosphorylated mTOR. Existing evidence clearly supports the use of rapamycin and metformin especially in the presence of probiotics. It also highlighted the possible mechanism of action of the 2 drugs through AMPK and mTOR signaling pathways and offered preliminary data on the significant role of probiotics in the combination. Further investigation to clarify the exact role of probiotics and decipher in more details the involved pathways is needed.

Development of nanoparticulate systems with action in breast and ovarian cancer: nanotheragnostics

The use of nanoparticulate systems with action in breast and ovarian cancer has been highlighted in recent years as an alternative to increasing the therapeutic index of conventional anticancer drugs. Thus, nanoparticles have advantageous characteristics in the treatment of cancer. Several nanocarriers of drugs and nanoparticles are described in the literature. The pharmacokinetics of the drugs can be modified by the use of nanocarriers, which in turn facilitate the specific delivery of the drug to the tumour cell. Therefore, the present work is a review that examines some nanosystems with nanoparticles for action in the treatment of breast cancer and ovarian cancer.

Lactoferrin-tagged quantum dots-based theranostic nanocapsules for combined COX-2 inhibitor/herbal therapy of breast cancer

Aim: Herein, tumor-targeted quantum dots (QDs)-based theranostic nanocapsules (NCs) coloaded with celecoxib and honokiol were developed. Materials & methodology: The anionic CD44-targeting chondroitin sulfate and cationic low density lipoprotein (LDL)-targeting lactoferrin (LF) were sequentially assembled onto the surface of the positively charged oily core. As an imaging probe, highly fluorescent mercaptopropionic acid-capped cadmium telluride QDs were coupled to LF. Results: In vitro, fluorescence of QDs was quenched (OFF state) due to combined electron/energy transfer-mediated processes involving LF. After intracellular uptake of NCs, fluorescence was restored (ON state), thus enabled tracing their internalization. The NCs demonstrated enhanced cytotoxicity against breast cancer cells as well as superior in vivo antitumor efficacy. Conclusion: We propose these multifunctional nanotheranostics for imaging and targeted therapy of breast cancer.

Photosensitizer and Autophagy Promoter Coloaded ROS-Responsive Dendrimer-Assembled Carrier for Synergistic Enhancement of Tumor Growth Suppression

Reactive oxygen species (ROS) generated during photodynamic therapy (PDT) can trigger autophagy. However, little research is focused on whether there is a synergistic anticancer effect with PDT if extra autophagy promoter or inhibitor is added. Here, it is found that autophagy promotion significantly enhances the PDT activity to cancer cells. Based on this preliminary result, a ROS-sensitive self-assembled dendrimer nanoparticle is exploited as a carrier to codeliver an autophagy promoter (rapamycin, Rapa) and photosensitizer (phthalocyanine, Pc) to the tumor. After entrapped by cancer cells and irradiated by light, the ROS generated in PDT process of Pc can trigger nanoparticle destruction to release Rapa, thus initiating the autophagy process and remarkably enhancing the efficacy of PDT, leading to efficient tumor suppression.

Layer-by-layer gelatin/chondroitin quantum dots-based nanotheranostics: combined rapamycin/celecoxib delivery and cancer imaging

Aim: Nanotheranostics consisting of highly-fluorescent quantum dots coupled with gelatin/chondroitin layer-by-layer assembled nanocapsules were developed. Materials & methods: The hydrophobic drugs celecoxib (CXB) and rapamycin (RAP) were co-loaded into the oily core of nanocapsules (NCs) to enable synergistic growth inhibition of breast cancer cells. To overcome the nonspecific binding of actively targeted CS-NCs with normal cells, a matrix metalloproteinase (MMP-2)-degradable cationic gelatin layer was electrostatically deposited onto the surface of the negatively-charged CS-NCs. Results: The prepared nanocarriers displayed strong fluorescence which enabled tracing their internalization into cancer cells. An enhanced cytotoxicity of the NCs against breast cancer cells was demonstrated. In vivo, the nanoplatforms displayed superior antitumor efficacy as well as nonimmunogenic response. Conclusion: Therefore, these multifunctional nanoplatforms could be used as potential cancer theranostics.

Nanoparticles and Controlled Delivery for Bioactive Compounds: Outlining Challenges for New "Smart-Foods" for Health

Nanotechnology is a field of research that has been stressed as a very valuable approach for the prevention and treatment of different human health disorders. This has been stressed as a delivery system for the therapeutic fight against an array of pathophysiological situations. Actually, industry has applied this technology in the search for new oral delivery alternatives obtained upon the modification of the solubility properties of bioactive compounds. Significant works have been made in the last years for testing the input that nanomaterials and nanoparticles provide for an array of pathophysiological situations. In this frame, this review addresses general questions concerning the extent to which nanoparticles offer alternatives that improve therapeutic value, while avoid toxicity, by releasing bioactive compounds specifically to target tissues affected by specific chemical and pathophysiological settings. In this regard, to date, the contribution of nanoparticles to protect encapsulated bioactive compounds from degradation as a result of gastrointestinal digestion and cellular metabolism, to enable their release in a controlled manner, enhancing biodistribution of bioactive compounds, and to allow them to target those tissues affected by biological disturbances has been demonstrated.

E-selectin targeted immunoliposomes for rapamycin delivery to activated endothelial cells

Activated endothelial cells play a pivotal role in the pathology of inflammatory disorders and thus present a target for therapeutic intervention by drugs that intervene in inflammatory signaling cascades, such as rapamycin (mammalian target of rapamycin (mTOR) inhibitor). In this study we developed anti-E-selectin immunoliposomes for targeted delivery to E-selectin over-expressing tumor necrosis factor-α (TNF-α) activated endothelial cells. Liposomes composed of 1,2-dipalmitoyl-sn-glycero-3.;hosphocholine (DPPC), Cholesterol, and 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)-2000]-maleimide (DSPE-PEG-Mal) were loaded with rapamycin via lipid film hydration, after which they were further functionalized by coupling N-succinimidyl-S-acetylthioacetate (SATA)-modified mouse anti human E-selectin antibodies to the distal ends of the maleimidyl (Mal)-PEG groups. In cell binding assays, these immunoliposomes bound specifically to TNF-α activated endothelial cells. Upon internalization, rapamycin loaded immunoliposomes inhibited proliferation and migration of endothelial cells, as well as expression of inflammatory mediators. Our findings demonstrate that rapamycin-loaded immunoliposomes can specifically inhibit inflammatory responses in inflamed endothelial cells.

Nanoparticulate strategies for the treatment of polyglutamine diseases by halting the protein aggregation process

Polyglutamine (polyQ) diseases are a class of neurodegenerative disorders that cause cellular dysfunction and, eventually, neuronal death in specific regions of the brain. Neurodegeneration is linked to the misfolding and aggregation of expanded polyQ-containing proteins, and their inhibition is one of major therapeutic strategies used commonly. However, successful treatment has been limited to date because of the intrinsic properties of therapeutic agents (poor water solubility, low bioavailability, poor pharmacokinetic properties), and difficulty in crossing physiological barriers, including the blood-brain barrier (BBB). In order to solve these problems, nanoparticulate systems with dimensions of 1-1000 nm able to incorporate small and macromolecules with therapeutic value, to protect and deliver them directly to the brain, have recently been developed, but their use for targeting polyQ disease-mediated protein misfolding and aggregation remains scarce. This review provides an update of the polyQ protein aggregation process and the development of therapeutic strategies for halting it. The main features that a nanoparticulate system should possess in order to enhance brain delivery are discussed, as well as the different types of materials utilized to produce them. The final part of this review focuses on the potential application of nanoparticulate system strategies to improve the specific and efficient delivery of therapeutic agents to the brain for the treatment of polyQ diseases.

Fabrication of PDEAEMA-based pH-responsive mixed micelles for application in controlled doxorubicin release

Co-micellization of MPEG–PDEAEMA and MPEG–PCL was carried out to enhance the drug loading content and realize pH-responsive release.

Biomaterials to suppress cancer stem cells and disrupt their tumoral niche

Lack of improvement in the treatment options of several types of cancer can largely be attributed to the presence of a subpopulation of cancer cells with stem cell signatures and to the tumoral niche that supports and protects these cells. This review analyses the main strategies that specifically modulate or suppress cancer stem cells (CSCs) and the tumoral niche (TN), focusing on the role of biomaterials (i.e. implants, nanomedicines, etc.) in these therapies. In the case of CSCs, we discuss differentiation therapies and the disruption of critical cellular signaling networks. For the TN, we analyze diverse strategies to modulate tumor hypervascularization and hypoxia, tumor extracellular matrix, and the inflammatory and tumor immunosuppressive environment. Due to their capacity to control drug disposition and integrate diverse functionalities, biomaterial-based therapies can provide important benefits in these strategies. We illustrate this by providing case studies where biomaterial-based therapies either show CSC suppression and TN disruption or improved delivery of major modulators of these features. Finally, we discuss the future of these technologies in the framework of these emerging therapeutic concepts.

Synthesis of three-arm block copolymer poly(lactic-co-glycolic acid)-poly(ethylene glycol) with oxalyl chloride and its application in hydrophobic drug delivery

PURPOSE

Synthesis of star-shaped block copolymer with oxalyl chloride and preparation of micelles to assess the prospect for drug-carrier applications.

MATERIALS AND METHODS

Three-arm star block copolymers of poly(lactic-co-glycolic acid) (3S-PLGA)-polyethylene glycol (PEG) were synthesized by ring-opening polymerization, then PEG as the hydrophilic block was linked to the terminal hydroxyl of 3S-PLGA with oxalyl chloride. Fourier-transform infrared (FT-IR) spectroscopy, gel-permeation chromatography (GPC), hydrogen nuclear magnetic resonance (¹H-NMR) spectra, and differential scanning calorimetry were employed to identify the structure and properties of 3S-PLGA-PEG. Rapamycin (RPM)-loaded micelles were prepared by solvent evaporation, and pyrene was used as the fluorescence probe to detect the critical micelle concentration of the copolymer. The particle size, distribution, and ζ-potential of the micelles were determined by dynamic light scattering, and the morphology of the RPM-loaded micelles was analyzed by transmission electron microscopy. High-performance liquid chromatography was conducted to analyze encapsulation efficiency and drug-loading capacity, as well as the release behavior of RPM-loaded micelles. The biocompatibility of material and the cytostatic effect of RPM-loaded micelles were investigated by Cell Counting Kit 8 assay.

RESULTS

FT-IR, GPC, and ¹H-NMR suggested that 3S-PLGA-PEG was successfully synthesized. The RPM-loaded micelles prepared with the 3S-PLGA-PEG possessed good properties. The micelles had good average diameter and encapsulation efficiency. For in vitro release, RPM was released slowly from 3S-PLGA-PEG micelles, showing that 3S-PLGA-PEG-RPM exhibited a better and longer antiproliferative effect than free RPM.

CONCLUSION

In this study, we first used oxalyl chloride as the linker to synthesize 3S-PLGA-PEG successfully, and compared with reported literature, this method shortened the reaction procedure and improved the reaction yield. The micelles prepared with this material proved suitable for drug-carrier application.

Layer-by-layer-coated lyotropic liquid crystalline nanoparticles for active tumor targeting of rapamycin

Aim: This work spotlights on fabrication of CD44-tropic, layer-by-layer (LbL) coated, liquid crystalline nanoparticles of rapamycin (Rap-LbL-LCNPs) to enhance its water solubility and enable its anticancer use. Methods: Rap-LCNPs were fabricated using hydrotrope method and then coated using LbL self-assembly technique. Results: LbL coating strategy successfully reduced monoolein-induced hemolysis and increased LCNPs serum stability. Lyophilized Rap-LbL-LCNPs were successfully sterilized using γ-radiations. In CD44-overexpressed MDA-MB-231 cells, Rap-LbL-LCNPs demonstrated superior cytotoxicity compared with the nontargeted formulation. Rap-LbL-LCNPs showed 3.35-fold increase in bioavailability compared with free drug. Rap-LbL-LCNPs significantly inhibited tumor growth, enhanced animal survival and reduced nephrotoxic and hyperglycemic effects of Rap. Conclusion: LbL coating strategy of Rap-LCNPs could serve as a promising approach that facilitates Rap use in cancer therapy.

Encapsulation and Controlled Release of Rapamycin from Polycaprolactone Nanoparticles Prepared by Membrane Micromixing Combined with Antisolvent Precipitation

Rapamycin-loaded polycaprolactone nanoparticles (RAPA-PCL NPs) with a polydispersity index of 0.006-0.073 were fabricated by antisolvent precipitation combined with micromixing using a ringed stainless steel membrane with 10 μm diameter laser-drilled pores. The organic phase composed of 6 g L^-1 PCL and 0.6-3.0 g L^-1 RAPA in acetone was injected through the membrane at 140 L m^-2 h^-1 into 0.2 wt % aqueous poly(vinyl alcohol) solution stirred at 1300 rpm, resulting in a Z-average mean of 189-218 nm, a drug encapsulation efficiency of 98.8-98.9%, and a drug loading in the NPs of 9-33%. The encapsulation of RAPA was confirmed by UV-vis spectroscopy, XRD, DSC, and ATR-FTIR. The disappearance of sharp characteristic peaks of crystalline RAPA in the XRD pattern of RAPA-PCL NPs revealed that the drug was molecularly dispersed in the polymer matrix or RAPA and PCL were present in individual amorphous domains. The rate of drug release in pure water was negligible due to low aqueous solubility of RAPA. RAPA-PCL NPs released more than 91% of their drug cargo after 2.5 h in the release medium composed of 0.78-1.5 M of the hydrotropic agent N,N-diethylnicotinamide, 10 vol % ethanol, and 2 vol % Tween 20 in phosphate buffered saline. The dissolution of RAPA was slower when the drug was embedded in the PCL matrix of the NPs than dispersed in the form of pure RAPA nanocrystals.

Development of a multi-target peptide for potentiating chemotherapy by modulating tumor microenvironment

Finding effective cures against aggressive malignancy remains a major challenge in cancer chemotherapy. Here, we report a "tadpole"-like peptide by covalently conjugating the alanine-alanine-asparagine "tail" residual to the cyclic tumor homing peptide iRGD (CCRGDKGPDC) to afford nRGD, which significantly enhanced tumoricidal effects of doxorubicin, by either co-administered as a physical mixture or as a targeting ligand covalently conjugated to the liposomal carrier. Given twice at an equivalent dose of 5 mg/kg, doxorubicin loaded liposomes modified with nRGD (nRGD-Lipo-Dox) showed excellent antitumor efficacy in 4T1 breast cancer mice, of which 44.4% remained alive for over 90 days without recurrence during the period of investigation. The dramatic improvement in antitumor efficacy was attributed to nRGD-Lipo-Dox which appeared to specifically interact with tumor vascular endothelial cells to achieve efficient tumor penetration, and modulate tumor microenvironment with depletion of tumor associated macrophages.

Synthesis and Characterization of Nanocomposite Microparticles (nCmP) for the Treatment of Cystic Fibrosis-Related Infections

PURPOSE

Pulmonary antibiotic delivery is recommended as maintenance therapy for cystic fibrosis (CF) patients who experience chronic infections. However, abnormally thick and sticky mucus present in the respiratory tract of CF patients impairs mucus penetration and limits the efficacy of inhaled antibiotics. To overcome the obstacles of pulmonary antibiotic delivery, we have developed nanocomposite microparticles (nCmP) for the inhalation application of antibiotics in the form of dry powder aerosols.

METHODS

Azithromycin-loaded and rapamycin-loaded polymeric nanoparticles (NP) were prepared via nanoprecipitation and nCmP were prepared by spray drying and the physicochemical characteristics were evaluated.

RESULTS

The nanoparticles were 200 nm in diameter both before loading into and after redispersion from nCmP. The NP exhibited smooth, spherical morphology and the nCmP were corrugated spheres about 1 μm in diameter. Both drugs were successfully encapsulated into the NP and were released in a sustained manner. The NP were successfully loaded into nCmP with favorable encapsulation efficacy. All materials were stable at manufacturing and storage conditions and nCmP were in an amorphous state after spray drying. nCmP demonstrated desirable aerosol dispersion characteristics, allowing them to deposit into the deep lung regions for effective drug delivery.

CONCLUSIONS

The described nCmP have the potential to overcome mucus-limited pulmonary delivery of antibiotics.

Vitamin E containing polymer micelles for reducing normal cell cytotoxicity and enhancing chemotherapy efficacy

An α-tocopheryl succinate (α-TOS) containing diblock copolymer micellar system was used to deliver doxorubicin (Dox), an anticancer drug, for HCT116 colon cancer therapy. The α-TOS containing diblock copolymers were synthesized by conjugation of α-TOS molecules and a mPEG-b-PHEMA hydrophilic diblock copolymer by ester bonds. The Dox-loaded polymeric micelles were then obtained by solvent exchange process. In acidic surroundings such as endosomes or secondary lysosomes, the structures of the Dox-loaded polymeric micelles deformed and released the drug loads. Additionally, Dox-loaded polymeric micelles enhanced the cytotoxicity of Dox and α-TOS to cancer cells in vitro. Dox-loaded polymeric micelles also showed an exceptional tumor inhibiting effect in vivo. This study indicates that the α-TOS containing polymeric micelle system can be used as a drug carrier for cancer therapy.

Cellular and molecular targeting for nanotherapeutics in transplantation tolerance

The induction of donor-specific tolerance to transplanted cells and organs, while preserving immune function as a whole, remains a highly sought after and elusive strategy for overcoming transplant rejection. Tolerance necessitates modulating a diverse array of cell types that recognize and respond to alloantigens, including antigen presenting cells and T lymphocytes. Nanotherapeutic strategies that employ cellular and biomaterial engineering represent an emerging technology geared towards the goal of inducing transplant tolerance. Nanocarriers offer a platform for delivering antigens of interest to specific cell types in order to achieve tolerogenic antigen presentation. Furthermore, the technologies also provide an opportunity for local immunomodulation at the graft site. Nanocarriers delivering a combination of antigens and immunomodulating agents, such as rapamycin, provide a unique technology platform with the potential to enhance outcomes for the induction of transplant tolerance.

A new model of cuprizone-mediated demyelination/remyelination

In the central nervous system, demyelinating diseases, such as multiple sclerosis, result in devastating long-term neurologic damage, in part because of the lack of effective remyelination in the adult human brain. One model used to understand the mechanisms regulating remyelination is cuprizone-induced demyelination, which allows investigation of remyelination mechanisms in adult animals following toxin-induced demyelination. Unfortunately, the degree of demyelination in the cuprizone model can vary, which complicates understanding the process of remyelination. Previous work in our laboratory demonstrated that the Akt/mTOR pathway regulates active myelination. When given to young postnatal mice, the mTOR inhibitor, rapamycin, inhibits active myelination. In the current study, the cuprizone model was modified by the addition of rapamycin during cuprizone exposure. When administered together, cuprizone and rapamycin produced more complete demyelination and provided a longer time frame over which to investigate remyelination than treatment with cuprizone alone. The consistency in demyelination will allow a better understanding of the mechanisms initiating remyelination. Furthermore, the slower rate of remyelination provides a longer window of time in which to investigate the diverse contributing factors that regulate remyelination. This new model of cuprizone-induced demyelination could potentially aid in identification of new therapeutic targets to enhance remyelination in demyelinating diseases.

Immunosuppressive and anti-inflammatory properties of engineered nanomaterials

Nanoparticle interactions with various components of the immune system are determined by their physicochemical properties such as size, charge, hydrophobicity and shape. Nanoparticles can be engineered to either specifically target the immune system or to avoid immune recognition. Nevertheless, identifying their unintended impacts on the immune system and understanding the mechanisms of such accidental effects are essential for establishing a nanoparticle's safety profile. While immunostimulatory properties have been reviewed before, little attention in the literature has been given to immunosuppressive and anti-inflammatory properties. The purpose of this review is to fill this gap. We will discuss intended immunosuppression achieved by either nanoparticle engineering, or the use of nanoparticles to carry immunosuppressive or anti-inflammatory drugs. We will also review unintended immunosuppressive properties of nanoparticles per se and consider how such properties could be either beneficial or adverse.

Rapamycin alleviates brain edema after focal cerebral ischemia reperfusion in rats

Brain edema is a major consequence of cerebral ischemia reperfusion. However, few effective therapeutic options are available for retarding the brain edema progression after cerebral ischemia. Recently, rapamycin has been shown to produce neuroprotective effects in rats after cerebral ischemia reperfusion. Whether rapamycin could alleviate this brain edema injury is still unclear. In this study, the rat stroke model was induced by a 1-h left transient middle cerebral artery occlusion using an intraluminal filament, followed by 48 h of reperfusion. The effects of rapamycin (250 μg/kg body weight, intraperitoneal; i.p.) on brain edema progression were evaluated. The results showed that rapamycin treatment significantly reduced the infarct volume, the water content of the brain tissue and the Evans blue extravasation through the blood-brain barrier (BBB). Rapamycin treatment could improve histological appearance of the brain tissue, increased the capillary lumen space and maintain the integrity of BBB. Rapamycin also inhibited matrix metalloproteinase 9 (MMP9) and aquaporin 4 (AQP4) expression. These data imply that rapamycin could improve brain edema progression after reperfusion injury through maintaining BBB integrity and inhibiting MMP9 and AQP4 expression. The data of this study provide a new possible approach for improving brain edema after cerebral ischemia reperfusion by administration of rapamycin.

Multifunctional nanomicellar systems for delivering anticancer drugs

Most anticancer drugs cause severe side effect due to the lack of selectivity for cancer cells. In recent years, new strategies of micellar systems, which design for specifically target anticancer drugs to tumors, are developed at the forefront of polymeric science. To improve efficiency of delivery and cancer specificity, considerable emphasis has been placed on the development of micellar systems with passive and active targeting. In this review article, we summarized various strategies of designing multifunctional micellar systems in the purpose of improving delivery efficiency. Micellar systems compose of a multifunctional copolymer or a mixture of two or more copolymers with different properties is a plausible approach to tuning the resulting properties and satisfied various requirements for anticancer drug delivery. It appears that multifunctional micellar systems hold great potential in cancer therapy.

Bioavailability of phytochemicals and its enhancement by drug delivery systems

Issues of poor oral bioavailability of cancer chemopreventives have hindered progress in cancer prevention. Novel delivery systems that modulate the pharmacokinetics of existing drugs, such as nanoparticles, cyclodextrins, niosomes, liposomes and implants, could be used to enhance the delivery of chemopreventive agents to target sites. The development of new approaches in prevention and treatment of cancer could encompass new delivery systems for approved and newly investigated compounds. In this review, we discuss some of the delivery approaches that have already made an impact by either delivering a drug to target tissue or increasing its bioavailability by many fold.