Concurrently suppressing multidrug resistance and metastasis of breast cancer by co-delivery of paclitaxel and honokiol with pH-sensitive polymeric micelles

Interactions between Dietary Antioxidants, Dietary Fiber and the Gut Microbiome: Their Putative Role in Inflammation and Cancer

The intricate relationship between the gastrointestinal (GI) microbiome and the progression of chronic non-communicable diseases underscores the significance of developing strategies to modulate the GI microbiota for promoting human health. The administration of probiotics and prebiotics represents a good strategy that enhances the population of beneficial bacteria in the intestinal lumen post-consumption, which has a positive impact on human health. In addition, dietary fibers serve as a significant energy source for bacteria inhabiting the cecum and colon. Research articles and reviews sourced from various global databases were systematically analyzed using specific phrases and keywords to investigate these relationships. There is a clear association between dietary fiber intake and improved colon function, gut motility, and reduced colorectal cancer (CRC) risk. Moreover, the state of health is reflected in the reciprocal and bidirectional relationships among food, dietary antioxidants, inflammation, and body composition. They are known for their antioxidant properties and their ability to inhibit angiogenesis, metastasis, and cell proliferation. Additionally, they promote cell survival, modulate immune and inflammatory responses, and inactivate pro-carcinogens. These actions collectively contribute to their role in cancer prevention. In different investigations, antioxidant supplements containing vitamins have been shown to lower the risk of specific cancer types. In contrast, some evidence suggests that taking antioxidant supplements can increase the risk of developing cancer. Ultimately, collaborative efforts among immunologists, clinicians, nutritionists, and dietitians are imperative for designing well-structured nutritional trials to corroborate the clinical efficacy of dietary therapy in managing inflammation and preventing carcinogenesis. This review seeks to explore the interrelationships among dietary antioxidants, dietary fiber, and the gut microbiome, with a particular focus on their potential implications in inflammation and cancer.

The Anticancer Application of Delivery Systems for Honokiol and Magnolol

Cancer is a leading cause of death worldwide, and the effectiveness of treatment is consistently not at a satisfactory level. This review thoroughly examines the present knowledge and perspectives of honokiol (HON) in cancer therapeutics. The paper synthesizes critical insights into the molecular mechanisms underlying the observed anticancer effects, emphasizing both in vitro and in vivo studies. The effects of HON application, primarily in the common types of cancers, are presented. Because the therapeutic potential of HON may be limited by its physicochemical properties, appropriate delivery systems are sought to overcome this problem. This review discusses the effect of different nanotechnology-based delivery systems on the efficiency of HON. The data presented show that HON exhibits anticancer effects and can be successfully administered to the site of action. Honokiol exerts its anticancer activity through several mechanisms. Moreover, some authors used the combinations of classical anticancer drugs with HON. Such an approach is very interesting and worth further investigation. Understanding HON's multiple molecular mechanisms would provide valuable insights into how HON might be developed as an effective therapeutic. Therefore, further research is needed to explore its specific applications and optimize its efficacy in diverse cancer types.

Upregulation of tumor suppressor PIAS3 by Honokiol promotes tumor cell apoptosis via selective inhibition of STAT3 tyrosine 705 phosphorylation

The natural product Honokiol exhibits robust antitumor activity against a range of cancers, and it has also received approval to undergo phase I clinical trial testing. We confrmed that honokiol can promote the apoptotic death of tumor cells through cell experiments. Then siRNA constructs specific for PIAS3, PIAS3 overexpression plasmid and the mutation of the STAT3 Tyr705 residue were used to confirm the mechanism of Honokiol-induced apoptosis. Finally, we confrmed that honokiol can promote PIAS3 upregulation, in turn suppressing STAT3 Tyr705 phosphorylation through the in vivo and in vitro experiments. Honokiol was ultimately found to reduce tumor cell viability by promoting apoptosis through a mechanism dependent on the ability of Honokiol to promote PIAS3 upregulation and the selective inhibition of p-STAT3 (Tyr705) without affecting p-STAT3 (Ser727) or p-STAT1 (Tyr701) levels. PIAS3 knockdown and overexpression in tumor cells altered STAT3 activation and associated DNA binding activity through the control of Tyr705 phosphorylation via PIAS3-STAT3 complex formation, ultimately shaping Honokiol-induced tumor cell apoptosis. Honokiol was also confirmed to significantly prolong the survival of mice bearing xenograft tumors in a PIAS3-dependent fashion. Together, these findings highlight a novel pathway through which Honokiol can promote PIAS3 upregulation, in turn suppressing STAT3 Tyr705 phosphorylation and promoting the apoptotic death of tumor cells.

Application of Electrospun Drug-Loaded Nanofibers in Cancer Therapy

In the 21st century, chemotherapy stands as a primary treatment method for prevalent diseases, yet drug resistance remains a pressing challenge. Utilizing electrospinning to support chemotherapy drugs offers sustained and controlled release methods in contrast to oral and implantable drug delivery modes, which enable localized treatment of distinct tumor types. Moreover, the core-sheath structure in electrospinning bears advantages in dual-drug loading: the core and sheath layers can carry different drugs, facilitating collaborative treatment to counter chemotherapy drug resistance. This approach minimizes patient discomfort associated with multiple-drug administration. Electrospun fibers not only transport drugs but can also integrate metal particles and targeted compounds, enabling combinations of chemotherapy with magnetic and heat therapies for comprehensive cancer treatment. This review delves into electrospinning preparation techniques and drug delivery methods tailored to various cancers, foreseeing their promising roles in cancer treatment.

Tumor microenvironment-activated, immunomodulatory nanosheets loaded with copper(II) and 5-FU for synergistic chemodynamic therapy and chemotherapy

The tumor microenvironment (TME) has a redox state that differs greatly from normal tissues, as characterized by the overexpression of H2O2 and glutathione (GSH). To address the GSH-related restrictions on chemodynamic therapy (CDT) efficacy, we have developed a Cu(II)-based CDT strategy. In this study, a novel organic-inorganic hybrid drug delivery system (LDH/HA/5-FU) was conceived and prepared by the intercalation of 5-FU into the interlayer of copper-aluminum layered double hydroxide (CuAl-LDH) via ion exchange strategy and the adsorption of hyaluronic acid (HA) on the surface of CuAl-LDH. Taking advantage of the pH-degradable property of CuAl-LDH and the CD44-targeting property of HA, the formed LDH/HA/5-FU nanosheets could specifically target tumor cells' overexpressing CD44 receptor, rapidly release Cu(II) and 5-FU in tumor cells, inducing tumor cell apoptosis and cuproptosis, and long-term intracellular GSH depletion and toxic hydroxyl radicals (·OH) generation could be achieved through the cyclic catalytic reaction of Cu(I)/Cu(II). Meanwhile, peritumoral injection of LDH/HA/5-FU nanosheets might function as an adjuvant to increase the levels of antitumor tumor-associated macrophages (TAMs) and T cells. In vivo experiments further verified that the intelligently designed LDH/HA/5-FU nanosheets successfully promoted the immune systems, with an excellent inhibition efficacy towards tumors by combining Cu-based CDT and chemotherapy, showing promising potential for solid tumor treatments.

Honokiol and its analogues as anticancer compounds: Current mechanistic insights and structure-activity relationship

Lignans are plant-derived polyphenolic compounds with a plethora of biological applications. Also, regarded as phytoestrogens, the lignans offer a variety of health benefits of which the anti-cancer effects are the most attractive. Honokiol is a lignan isolated from various parts of trees belonging to the genus Magnolia. The bioactivity of honokiol is attributed to its characteristic physical properties, which include small size and the presence of two phenolic groups that may interact with proteins in cell membranes via hydrophobic interactions, aromatic pi orbital co-valency, and hydrogen bonding. The hydrophobicity of honokiol enables its rapid dissolution in lipids and the crossing of physiological barriers, including the blood-brain barrier and cerebrospinal fluid. These factors contribute towards the high bioavailability of honokiol which further support its candidature in medicinal research. Therefore, the anticancer properties of honokiol are of particular interest as many of the contemporary anticancer drugs suffer from bioavailability drawbacks, which necessitates the identification and development of novel candidate molecules directed as anticancer chemotherapeutics. The antioncogenic profile of honokiol also arises from the regulation of various signalling pathways associated with oncogenesis, arresting of the cell cycle by regulation of cyclic proteins, upregulation of epithelial markers and downregulation of mesenchymal markers leading to the inhibition of epithelial-mesenchymal transition, and preventing the metastasis by restricting cell migration and invasion due to the downregulation of matrix-metalloproteinases. In this review, we discuss the anticancer properties of honokiol.

Nanotechnology-Based Drug Delivery Systems for Honokiol: Enhancing Therapeutic Potential and Overcoming Limitations

Honokiol (HNK) is a small-molecule polyphenol that has garnered considerable attention due to its diverse pharmacological properties, including antitumor, anti-inflammatory, anti-bacterial, and anti-obesity effects. However, its clinical application is restricted by challenges such as low solubility, poor bioavailability, and rapid metabolism. To overcome these limitations, researchers have developed a variety of nano-formulations for HNK delivery. These nano-formulations offer advantages such as enhanced solubility, improved bioavailability, extended circulation time, and targeted drug delivery. However, existing reviews of HNK primarily focus on its clinical and pharmacological features, leaving a gap in the comprehensive evaluation of HNK delivery systems based on nanotechnology. This paper aims to bridge this gap by comprehensively reviewing different types of nanomaterials used for HNK delivery over the past 15 years. These materials encompass vesicle delivery systems, nanoparticles, polymer micelles, nanogels, and various other nanocarriers. The paper details various HNK nano-delivery strategies and summarizes their latest applications, development prospects, and future challenges. To compile this review, we conducted an extensive search using keywords such as "honokiol", "nanotechnology", and "drug delivery system" on reputable databases, including PubMed, Scopus, and Web of Science, covering the period from 2008 to 2023. Through this search, we identified and selected approximately 90 articles that met our specific criteria.

(Nano)platforms in breast cancer therapy: Drug/gene delivery, advanced nanocarriers and immunotherapy

Breast cancer is the most malignant tumor in women, and there is no absolute cure for it. Although treatment modalities including surgery, chemotherapy, and radiotherapy are utilized for breast cancer, it is still a life-threatening disease for humans. Nanomedicine has provided a new opportunity in breast cancer treatment, which is the focus of the current study. The nanocarriers deliver chemotherapeutic agents and natural products, both of which increase cytotoxicity against breast tumor cells and prevent the development of drug resistance. The efficacy of gene therapy is boosted by nanoparticles and the delivery of CRISPR/Cas9, Noncoding RNAs, and RNAi, promoting their potential for gene expression regulation. The drug and gene codelivery by nanoparticles can exert a synergistic impact on breast tumors and enhance cellular uptake via endocytosis. Nanostructures are able to induce photothermal and photodynamic therapy for breast tumor ablation via cell death induction. The nanoparticles can provide tumor microenvironment remodeling and repolarization of macrophages for antitumor immunity. The stimuli-responsive nanocarriers, including pH-, redox-, and light-sensitive, can mediate targeted suppression of breast tumors. Besides, nanoparticles can provide a diagnosis of breast cancer and detect biomarkers. Various kinds of nanoparticles have been employed for breast cancer therapy, including carbon-, lipid-, polymeric- and metal-based nanostructures, which are different in terms of biocompatibility and delivery efficiency.

Synchronized delivery of dual-drugs for potentiating combination chemotherapy based on smart triple-responsive polymeric micelles

Here, we combined reversible addition-fragmentation chain transfer (RAFT) polymerization and amide coupling reaction to develop a novel drug-polymer conjugate using poly(AMA-co-IMMA)-b-poly(OEGMA) (termed as PAIPO) as nanocarriers. In order to enhance cellular uptake and obtain subsequent endo/lysosomal escape capacity, the dual-drugs-conjugated prodrug was then coupled with 2,3-dimethylmaleimide (DA) moieties and implanted with imidazolyl groups, respectively. Paclitaxel (PTX) was conjugated to PAIPO via 3,3'-dithiodipropionic acid (DPA) to construct a GSH-responsive moiety, while doxorubicin (DOX) was conjugated to PAIPO via 4-formyl benzoic acid to construct a pH-responsive moiety, which synergistically enabled a synchronized and precise drug delivery. The micelles self-assembled from DOX/PTX@PAIPO^DA showed an ideal average diameter (163.2-178.3 nm), contributing to passive targeting by the EPR effect. Moreover, a switch of the surface Zeta potential of micelles from steady negatively charged (- 9.74 ± 0.54 mV) at pH 7.4 to positively charged (+ 6.33 ± 1.25 mV) at pH 6.5, facilitated the long blood circulation and cellular endocytosis of micelles, respectively. More importantly, in vitro studies confirmed that ^DAM(DOX_n/PTX) exhibited a strong synergism against tumor cells, and under slightly acidic conditions (pH 6.5), the combination index (CI) values for ^DAM(DOX₁/PTX) on HeLa and Skov-3 cells were estimated to be 0.47 and 0.49 (previous to be 0.50 and 0.56 at pH 7.4), respectively. And in vivo results showed effective tumor accumulation potential, remarkable biosafety, and biocompatibility. Combined, such synchronized delivery approach based on multi-responsive micelles might potentiate the efficacy of combination chemotherapy in clinical cancer treatment.

Dual-drug codelivery nanosystems: An emerging approach for overcoming cancer multidrug resistance

Multidrug resistance (MDR) promotes tumor recurrence and metastasis and heavily reduces anticancer efficiency, which has become a primary reason for the failure of clinical chemotherapy. The mechanisms of MDR are so complex that conventional chemotherapy usually fails to achieve an ideal therapeutic effect and even accelerates the occurrence of MDR. In contrast, the combination of chemotherapy with dual-drug has significant advantages in tumor therapy. A novel dual-drug codelivery nanosystem, which combines dual-drug administration with nanotechnology, can overcome the application limitation of free drugs. Both the characteristics of nanoparticles and the synergistic effect of dual drugs contribute to circumventing various drug-resistant mechanisms in tumor cells. Therefore, developing dual-drug codelivery nanosystems with different multidrug-resistant mechanisms has an important reference value for reversing MDR and enhancing the clinical antitumor effect. In this review, the advantages, principles, and common codelivery nanocarriers in the application of dual-drug codelivery systems are summarized. The molecular mechanisms of MDR and the dual-drug codelivery nanosystems designed based on different mechanisms are mainly introduced. Meanwhile, the development prospects and challenges of codelivery nanosystems are also discussed, which provide guidelines to exploit optimized combined chemotherapy strategies in the future.

Polymeric Micelles for Breast Cancer Therapy: Recent Updates, Clinical Translation and Regulatory Considerations

With the growing burden of cancer, parallel advancements in anticancer nanotechnological solutions have been witnessed. Among the different types of cancers, breast cancer accounts for approximately 25% and leads to 15% of deaths. Nanomedicine and its allied fields of material science have revolutionized the science of medicine in the 21st century. Novel treatments have paved the way for improved drug delivery systems that have better efficacy and reduced adverse effects. A variety of nanoformulations using lipids, polymers, inorganic, and peptide-based nanomedicines with various functionalities are being synthesized. Thus, elaborate knowledge of these intelligent nanomedicines for highly promising drug delivery systems is of prime importance. Polymeric micelles (PMs) are generally easy to prepare with good solubilization properties; hence, they appear to be an attractive alternative over the other nanosystems. Although an overall perspective of PM systems has been presented in recent reviews, a brief discussion has been provided on PMs for breast cancer. This review provides a discussion of the state-of-the-art PMs together with the most recent advances in this field. Furthermore, special emphasis is placed on regulatory guidelines, clinical translation potential, and future aspects of the use of PMs in breast cancer treatment. The recent developments in micelle formulations look promising, with regulatory guidelines that are now more clearly defined; hence, we anticipate early clinical translation in the near future.

Expanding the arsenal against pulmonary diseases using surface-functionalized polymeric micelles: breakthroughs and bottlenecks

Pulmonary diseases such as lung cancer, asthma and tuberculosis have remained one of the common challenges globally. Polymeric micelles (PMs) have emerged as an effective technique for achieving targeted drug delivery for a local as well as a systemic effect. These PMs encapsulate and protect hydrophobic drugs, increase pulmonary targeting, decrease side effects and enhance drug efficacy through the inhalation route. In the current review, emphasis has been placed on the different barriers encountered by the drugs given via the pulmonary route and the mechanism of PMs in achieving drug targeting. The applications of PMs in different pulmonary diseases have also been discussed in detail.

Emerging Nano-Based Strategies Against Drug Resistance in Tumor Chemotherapy

Drug resistance is the most significant causes of cancer chemotherapy failure. Various mechanisms of drug resistance include tumor heterogeneity, tumor microenvironment, changes at cellular levels, genetic factors, and other mechanisms. In recent years, more attention has been paid to tumor resistance mechanisms and countermeasures. Nanomedicine is an emerging treatment platform, focusing on alternative drug delivery and improved therapeutic effectiveness while reducing side effects on normal tissues. Here, we reviewed the principal forms of drug resistance and the new possibilities that nanomaterials offer for overcoming these therapeutic barriers. Novel nanomaterials based on tumor types are an excellent modality to equalize drug resistance that enables gain more rational and flexible drug selectivity for individual patient treatment. With the emergence of advanced designs and alternative drug delivery strategies with different nanomaterials, overcome of multidrug resistance shows promising and opens new horizons for cancer therapy. This review discussed different mechanisms of drug resistance and recent advances in nanotechnology-based therapeutic strategies to improve the sensitivity and effectiveness of chemotherapeutic drugs, aiming to show the advantages of nanomaterials in overcoming of drug resistance for tumor chemotherapy, which could accelerate the development of personalized medicine.

Stromal Barrier-Dismantled Nanodrill-Like and Cancer Cell-Targeted pH-Responsive Polymeric Micelles for Further Enhancing the Anticancer Efficacy of Doxorubicin

Cancer-associated fibroblasts (CAFs) were believed to establish a tight physical barrier and a dense scaffold for tumor cells to make them maintain immunosuppression and drug resistance, strongly hindering nanoparticles to penetrate into the core of tumor tissues and limiting the performance of tumor cell-targeted nanoparticles. Here, we fabricated the substrate Z-Gly-Pro of fibroblast activation protein α (FAPα) and folic acid-codecorated pH-responsive polymeric micelles (dual ligand-modified PEOz-PLA polymeric micelles, DL-PP-PMs) that possessed nanodrill and tumor cell-targeted functions based on Z-Gly-pro-conjugated poly(2-ethyl-2-oxazoline)-poly(D,l-lactide) (ZGP-PEOz-PLA), folic acid (FA)-conjugated PEOz-PLA (FA-PEOz-PLA), and PEOz-PLA for cancer therapy. The micelles with about 40 nm particle size and a narrow distribution exhibited favorable pH-activated endo/lysosome escape induced by their pH responsibility. In addition, the enhancement of in vitro cellular uptake and cytotoxicity to folate receptors or FAPα-positive cells for doxorubicin (DOX)/DL-PP-PMs compared with DOX/PP-PMs evidenced the dual target ability of DOX/DL-PP-PMs, which was further supported by in vivo biodistribution results. As expected, in the human oral epidermal carcinoma (KB) cells xenograft nude mice model, the remarkable enhancement of antitumor efficacy for DOX/DL-PP-PMs with low toxicity was observed compared with DOX/FA-PP-PMs and DOX/ZGP-PP-PMs. The possible mechanism was elucidated to be the dismantling of the stromal barrier by nanodrill-like DOX/DL-PP-PMs via the deletion of CAFs evidenced by the downregulation of α-SMA and inhibition of their functions proved by the decrease in the microvascular density labeled with CD31 and the reduction in the extracellular matrix detected by the collagen content, thereby promoting tumor penetration and enhancing their uptake by tumor cells. The present research offered an alternative approach integrating anticancer and antifibrosis effects in one delivery system to enhance the delivery efficiency and therapeutic efficacy of anticancer drugs.

Traditional herbal medicine and nanomedicine: Converging disciplines to improve therapeutic efficacy and human health

Traditional herbal medicine (THM), an ancient science, is a gift from nature. For thousands of years, it has helped humans fight diseases and protect life, health, and reproduction. Nanomedicine, a newer discipline has evolved from exploitation of the unique nanoscale morphology and is widely used in diagnosis, imaging, drug delivery, and other biomedical fields. Although THM and nanomedicine differ greatly in time span and discipline dimensions, they are closely related and are even evolving toward integration and convergence. This review begins with the history and latest research progress of THM and nanomedicine, expounding their respective developmental trajectory. It then discusses the overlapping connectivity and relevance of the two fields, including nanoaggregates generated in herbal medicine decoctions, the application of nanotechnology in the delivery and treatment of natural active ingredients, and the influence of physiological regulatory capability of THM on the in vivo fate of nanoparticles. Finally, future development trends, challenges, and research directions are discussed.

Drug Resistance in Metastatic Breast Cancer: Tumor Targeted Nanomedicine to the Rescue

Breast cancer, specifically metastatic breast, is a leading cause of morbidity and mortality in women. This is mainly due to relapse and reoccurrence of tumor. The primary reason for cancer relapse is the development of multidrug resistance (MDR) hampering the treatment and prognosis. MDR can occur due to a multitude of molecular events, including increased expression of efflux transporters such as P-gp, BCRP, or MRP1; epithelial to mesenchymal transition; and resistance development in breast cancer stem cells. Excessive dose dumping in chemotherapy can cause intrinsic anti-cancer MDR to appear prior to chemotherapy and after the treatment. Hence, novel targeted nanomedicines encapsulating chemotherapeutics and gene therapy products may assist to overcome cancer drug resistance. Targeted nanomedicines offer innovative strategies to overcome the limitations of conventional chemotherapy while permitting enhanced selectivity to cancer cells. Targeted nanotheranostics permit targeted drug release, precise breast cancer diagnosis, and importantly, the ability to overcome MDR. The article discusses various nanomedicines designed to selectively target breast cancer, triple negative breast cancer, and breast cancer stem cells. In addition, the review discusses recent approaches, including combination nanoparticles (NPs), theranostic NPs, and stimuli sensitive or “smart” NPs. Recent innovations in microRNA NPs and personalized medicine NPs are also discussed. Future perspective research for complex targeted and multi-stage responsive nanomedicines for metastatic breast cancer is discussed.

Nanotechnology-Based Drug Delivery to Improve the Therapeutic Benefits of NRF2 Modulators in Cancer Therapy

The disadvantages of conventional anticancer drugs, such as their low bioavailability, poor targeting efficacy, and serious side effects, have led to the discovery of new therapeutic agents and potential drug delivery systems. In particular, the introduction of nano-sized drug delivery systems (NDDSs) has opened new horizons for effective cancer treatment. These are considered potential systems that provide deep tissue penetration and specific drug targeting. On the other hand, nuclear factor erythroid 2-related factor 2 (NRF2)-based anticancer treatment approaches have attracted tremendous attention and produced encouraging results. However, the lack of effective formulation strategies is one of the factors that hinder the clinical application of NRF2 modulators. In this review, we initially focus on the critical role of NRF2 in cancer cells and NRF2-based anticancer treatment. Subsequently, we review the preparation and characterization of NDDSs encapsulating NRF2 modulators and discuss their potential for cancer therapy.

Cyclodextrin-Based Hybrid Polymeric Complex to Overcome Dual Drug Resistance Mechanisms for Cancer Therapy

Drug resistance always reduces the efficacy of chemotherapy, and the classical mechanisms of drug resistance include drug pump efflux and anti-apoptosis mediators-mediated non-pump resistance. In addition, the amphiphilic polymeric micelles with good biocompatibility and high stability have been proven to deliver the drug molecules inside the cavity into the cell membrane regardless of the efflux of the cell membrane pump. We designed a cyclodextrin (CD)-based polymeric complex to deliver chemotherapeutic doxorubicin (DOX) and Nur77ΔDBD gene for combating pumps and non-pump resistance simultaneously. The natural cavity structure of the polymeric complex, which was comprised with β-cyclodextrin-graft-(poly(ε-caprolactone)-adamantly (β-CD-PCL-AD) and β-cyclodextrin-graft-(poly(ε-caprolactone)-poly(2-(dimethylamino) ethyl methacrylate) (β-CD-PCL-PDMAEMA), can achieve the efficient drug loading and delivery to overcome pump drug resistance. The excellent Nur77ΔDBD gene delivery can reverse Bcl-2 from the tumor protector to killer for inhibiting non-pump resistance. The presence of terminal adamantyl (AD) could insert into the cavity of β-CD-PCL-PDMAEMA via host-guest interaction, and the releasing rate of polymeric inclusion complex was higher than that of the individual β-CD-PCL-PDMAEMA. The polymeric inclusion complex can efficiently deliver the Nur77ΔDBD gene than polyethylenimine (PEI-25k), which is a golden standard for nonviral vector gene delivery. The higher transfection efficacy, rapid DOX cellular uptake, and significant synergetic tumor cell viability inhibition were achieved in a pump and non-pump drug resistance cell model. The combined strategy with dual drug resistance mechanisms holds great potential to combat drug-resistant cancer.

Role of inflammatory microenvironment: potential implications for improved breast cancer nano-targeted therapy

Tumor cells, inflammatory cells and chemical factors work together to mediate complex signaling networks, which forms inflammatory tumor microenvironment (TME). The development of breast cancer is closely related to the functional activities of TME. This review introduces the origins of cancer-related chronic inflammation and the main constituents of inflammatory microenvironment. Inflammatory microenvironment plays an important role in breast cancer growth, metastasis, drug resistance and angiogenesis through multifactorial mechanisms. It is suggested that inflammatory microenvironment contributes to providing possible mechanisms of drug action and modes of drug transport for anti-cancer treatment. Nano-drug delivery system (NDDS) becomes a popular topic for optimizing the design of tumor targeting drugs. It is seen that with the development of therapeutic approaches, NDDS can be used to achieve drug-targeted delivery well across the biological barriers and into cells, resulting in superior bioavailability, drug dose reduction as well as off-target side effect elimination. This paper focuses on the review of modulation mechanisms of inflammatory microenvironment and combination with nano-targeted therapeutic strategies, providing a comprehensive basis for further research on breast cancer prevention and control.

Cisplatin prevents breast cancer metastasis through blocking early EMT and retards cancer growth together with paclitaxel

Cancer growth is usually accompanied by metastasis which kills most cancer patients. Here we aim to study the effect of cisplatin at different doses on breast cancer growth and metastasis.

Methods: We used cisplatin to treat breast cancer cells, then detected the migration of cells and the changes of epithelial-mesenchymal transition (EMT) markers by migration assay, Western blot, and immunofluorescent staining. Next, we analyzed the changes of RNA expression of genes by RNA-seq and confirmed the binding of activating transcription factor 3 (ATF3) to cytoskeleton related genes by ChIP-seq. Thereafter, we combined cisplatin and paclitaxel in a neoadjuvant setting to treat xenograft mouse models. Furthermore, we analyzed the association of disease prognosis with cytoskeletal genes and ATF3 by clinical data analysis.

Results: When administered at a higher dose (6 mg/kg), cisplatin inhibits both cancer growth and metastasis, yet with strong side effects, whereas a lower dose (2 mg/kg) cisplatin blocks cancer metastasis without obvious killing effects. Cisplatin inhibits cancer metastasis through blocking early steps of EMT. It antagonizes transforming growth factor beta (TGFβ) signaling through suppressing transcription of many genes involved in cytoskeleton reorganization and filopodia formation which occur early in EMT and are responsible for cancer metastasis. Mechanistically, TGFβ and fibronectin-1 (FN1) constitute a positive reciprocal regulation loop that is critical for activating TGFβ/SMAD3 signaling, which is repressed by cisplatin induced expression of ATF3. Furthermore, neoadjuvant administration of cisplatin at 2 mg/kg in conjunction with paclitaxel inhibits cancer growth and blocks metastasis without causing obvious side effects by inhibiting colonization of cancer cells in the target organs.

Conclusion: Thus, cisplatin prevents breast cancer metastasis through blocking early EMT, and the combination of cisplatin and paclitaxel represents a promising therapy for killing breast cancer and blocking tumor metastasis.

The Therapeutic Efficacy of Dendrimer and Micelle Formulations for Breast Cancer Treatment

Breast cancer is among the most common types of cancer in women and it is the cause of a high rate of mortality globally. The use of anticancer drugs is the standard treatment approach used for this type of cancer. However, most of these drugs are limited by multi-drug resistance, drug toxicity, poor drug bioavailability, low water solubility, poor pharmacokinetics, etc. To overcome multi-drug resistance, combinations of two or more anticancer drugs are used. However, the combination of two or more anticancer drugs produce toxic side effects. Micelles and dendrimers are promising drug delivery systems that can overcome the limitations associated with the currently used anticancer drugs. They have the capability to overcome drug resistance, reduce drug toxicity, improve the drug solubility and bioavailability. Different classes of anticancer drugs have been loaded into micelles and dendrimers, resulting in targeted drug delivery, sustained drug release mechanism, increased cellular uptake, reduced toxic side effects of the loaded drugs with enhanced anticancer activity in vitro and in vivo. This review article reports the biological outcomes of dendrimers and micelles loaded with different known anticancer agents on breast cancer in vitro and in vivo.

Stimuli-responsive Drug Delivery Nanocarriers in the Treatment of Breast Cancer

Stimuli-responsive drug-delivery nanocarriers (DDNs) have been increasingly reported in the literature as an alternative for breast cancer therapy. Stimuli-responsive DDNs are developed with materials that present a drastic change in response to intrinsic/chemical stimuli (pH, redox and enzyme) and extrinsic/physical stimuli (ultrasound, Near-infrared (NIR) light, magnetic field and electric current). In addition, they can be developed using different strategies, such as functionalization with signaling molecules, leading to several advantages, such as (a) improved pharmaceutical properties of liposoluble drugs, (b) selectivity with the tumor tissue decreasing systemic toxic effects, (c) controlled release upon different stimuli, which are all fundamental to improving the therapeutic effectiveness of breast cancer treatment. Therefore, this review summarizes the use of stimuli-responsive DDNs in the treatment of breast cancer. We have divided the discussions into intrinsic and extrinsic stimuli and have separately detailed them regarding their definitions and applications. Finally, we aim to address the ability of these stimuli-responsive DDNs to control the drug release in vitro and the influence on breast cancer therapy, evaluated in vivo in breast cancer models.

Targeted drug nanocrystals for pulmonary delivery: a potential strategy for lung cancer therapy

INTRODUCTION

Lung cancer and metastases are major concerns worldwide. Although systemic chemotherapy is the recommended treatment, it is associated with various disadvantages, including nonselective drug distribution and systemic toxicity. In contrast, the pulmonary route ensures the localized delivery of drugs to the lung. Still, the pulmonary route is prone to clearance, limited drug dissolution, and local toxicity to healthy lung cells. Drug nanocrystals provide a potential strategy to enhance the therapeutic efficacy and mitigate the limitations of pulmonary delivery.

AREAS COVERED

The development and potential application of nanocrystals in pulmonary delivery, their role in overcoming associated barriers, and strategies for site-specific and stimuli-responsive pulmonary delivery are outlined. This review also traces different in-vitro pulmonary models for assessments of the performance of drug nanocrystals and nanocrystals loaded carriers in pulmonary delivery.

EXPERT OPINION

Enhanced stability, high aerosolization performance, better particle size distribution, improved penetration, sustained release of the drug, and minimal excipients usage makes drug nanocrystal an ideal candidate for pulmonary delivery. Besides, drug nanocrystals may provide selective cellular internalization with minimum clearance and maximum deposition. Furthermore, surface modified nanocrystals and nanocrystals in nanocarriers can exhibit a more prolonged, and site-specific release of the drug to cancer cells in the lungs.

Targeted delivery of honokiol by zein/hyaluronic acid core-shell nanoparticles to suppress breast cancer growth and metastasis

Based on the antisolvent and electrostatic deposition methods, we fabricated zein/hyaluronic acid core-shell nanoparticles loaded with honokiol (HA-Zein-HNK), which could target delivery and enhance the therapeutic effect of the HNK. The prepared nanoparticles were found to have a mean size of 210.4 nm and negative surface charge. The HA-Zein-HNK nanoparticles exhibited improved antiproliferative and pro-apoptotic activities against 4T1 cells. Of note, the wound healing and transwell assessments indicated that the migration and invasion of 4T1 cells were markedly weakened by HA-Zein-HNK. Mechanistic insights revealed that HA-Zein-HNK downregulated the expressions of Vimentin and upregulated the expressions of E-cadherin. More importantly, an in vivo tissue distribution study demonstrated the excellent tumor target ability of HA-Zein. And these results correspond with the superior therapeutic efficacy of HA-Zein-HNK in 4T1 tumor bearing mice. In conclusion, we believe that HA-Zein nanoparticles may be served as a promising HNK delivery carrier for metastatic breast cancer therapy.

Chemotherapeutic Efficacy Enhancement in P-gp-Overexpressing Cancer Cells by Flavonoid-Loaded Polymeric Micelles

Multidrug resistance is the major problem in cancer treatment nowadays. Compounds from plants are the new targets to solve this problem. Quercetin (QCT), quercetrin (QTR), and rutin (RUT) are potential anticancer flavonoids but their poor water solubility leads to less efficacy. In this study, the polymeric micelles of benzoylated methoxy-poly (ethylene glycol)-b-oligo(ε-caprolactone) or mPEG-b-OCL-Bz loading with the flavonoids were prepared to solve these problems. The flavonoid-loaded micelles showed an average size of 13-20 nm and maximum loading capacity of 35% (w/w). The release of QCT (21%, 3 h) was lower than that of QTR (51%, 3 h) and RUT (58%, 3 h). QCT (free and micelle forms) exhibited significantly higher cytotoxicity against P-glycoprotein-overexpressing leukemia (K562/ADR) cells than QTR and RUT (p < 0.05). The results demonstrated that QCT-loaded micelles effectively reversed cytotoxicity of both doxorubicin (multidrug resistant reversing (δ) values up to 0.71) and daunorubicin (δ values up to 0.74) on K562/ADR cells. It was found that QCT-loaded micelles as well as empty polymeric micelles inhibited P-gp efflux of tetrahydropyranyl Adriamycin. Besides, mitochondrial membrane potential was decreased by QCT (in its free form and micellar formation). Our results suggested that the combination effects of polymeric micelles (inhibiting P-gp efflux) and QCT (interfering mitochondrial membrane potential) might be critical factors contributing to the reversing multidrug resistance of K562/ADR cells by QCT-loaded micelles. We concluded that QCT-loaded mPEG-b-OCL-Bz micelles are the attractive systems for overcoming multidrug-resistant cancer cells.

Hyaluronic acid-modified liposomal honokiol nanocarrier: Enhance anti-metastasis and antitumor efficacy against breast cancer

In an effort to enhance antitumor and anti-metastasis of breast cancer, honokiol (HNK) was encapsulated into hyaluronic acid (HA) modified cationic liposomes (Lip). The prepared HA-Lip-HNK had a spherical shape with a narrow size distribution. The enhanced antitumor efficacy of HA-Lip-HNK was investigated in 4T1 cells in vitro, wherein flow cytometry and confocal microscopy analysis revealed its HA/CD44-mediated greater cellular internalization. As anticipate, the significant cytotoxicity of the HA-Lip-HNK was also observed in 4T1 tumor spheroids. Furthermore, the superior prevention of tumor metastasis by HA-Lip-HNK was verified by in vitro anti-invasion, wound healing and anti-migration assessments, and in vivo bioluminescence imaging in pulmonary metastasis model. Finally, compared with unmodified liposomes, the HA-Lip-HNK exhibited higher tumor accumulation, and achieved a tumor growth inhibition rate of 59.5 %. As a result, the HA-Lip-HNK may serve as a promising tumor-targeted drug delivery strategy for the efficient therapy of metastatic breast cancer.

Preparation and Characterization of Honokiol Nanosuspensions and Preliminary Evaluation of Anti-Inflammatory Effect

The study mainly aimed to improve the solubility of honokiol (HK) by preparing honokiol nanosuspensions (HNS). In this study, HNS were obtained using Kolliphor®P407 (P407) as a stabilizer through melting method combined with high pressure homogenization (HPH). The crystalline state of HNS was confirmed through differential scanning calorimetry (DSC) and X-ray Diffraction (XRD). In vitro, the dissolution rate of HNS was significantly improved than that of pure HK. In vivo, higher anti-inflammatory activity was achieved after free HK had been made into HNS. There was no significant difference between the degree of edema (DE) of HNS group and that of aspirin group. Consequently, melting method combined with HPH was a potent technique to prepare HNS. Furthermore, nanosuspension was a valid formulation that could be utilized to enhance the anti-inflammatory effect of HK.

Alleviation of Multidrug Resistance by Flavonoid and Non-Flavonoid Compounds in Breast, Lung, Colorectal and Prostate Cancer

The aim of the manuscript is to discuss the influence of plant polyphenols in overcoming multidrug resistance in four types of solid cancers (breast, colorectal, lung and prostate cancer). Effective treatment requires the use of multiple toxic chemotherapeutic drugs with different properties and targets. However, a major cause of cancer treatment failure and metastasis is the development of multidrug resistance. Potential mechanisms of multidrug resistance include increase of drug efflux, drug inactivation, detoxification mechanisms, modification of drug target, inhibition of cell death, involvement of cancer stem cells, dysregulation of miRNAs activity, epigenetic variations, imbalance of DNA damage/repair processes, tumor heterogeneity, tumor microenvironment, epithelial to mesenchymal transition and modulation of reactive oxygen species. Taking into consideration that synthetic multidrug resistance agents have failed to demonstrate significant survival benefits in patients with different types of cancer, recent research have focused on beneficial effects of natural compounds. Several phenolic compounds (flavones, phenolcarboxylic acids, ellagitannins, stilbens, lignans, curcumin, etc.) act as chemopreventive agents due to their antioxidant capacity, inhibition of proliferation, survival, angiogenesis, and metastasis, modulation of immune and inflammatory responses or inactivation of pro-carcinogens. Moreover, preclinical and clinical studies revealed that these compounds prevent multidrug resistance in cancer by modulating different pathways. Additional research is needed regarding the role of phenolic compounds in the prevention of multidrug resistance in different types of cancer.

Multi pH-sensitive polymer–drug conjugate mixed micelles for efficient co-delivery of doxorubicin and curcumin to synergistically suppress tumor metastasis

Multi pH-responsive polymer-drug conjugate mixed micelles were fabricated to co-deliver doxorubicin and curcumin for synergistic suppression tumor metastasis via inhibiting the invasion, migration, intravasation and extravasation of tumor cells.

Honokiol: A Review of Its Anticancer Potential and Mechanisms

Cancer is characterised by uncontrolled cell division and abnormal cell growth, which is largely caused by a variety of gene mutations. There are continuous efforts being made to develop effective cancer treatments as resistance to current anticancer drugs has been on the rise. Natural products represent a promising source in the search for anticancer treatments as they possess unique chemical structures and combinations of compounds that may be effective against cancer with a minimal toxicity profile or few side effects compared to standard anticancer therapy. Extensive research on natural products has shown that bioactive natural compounds target multiple cellular processes and pathways involved in cancer progression. In this review, we discuss honokiol, a plant bioactive compound that originates mainly from the Magnolia species. Various studies have proven that honokiol exerts broad-range anticancer activity in vitro and in vivo by regulating numerous signalling pathways. These include induction of G0/G1 and G2/M cell cycle arrest (via the regulation of cyclin-dependent kinase (CDK) and cyclin proteins), epithelial-mesenchymal transition inhibition via the downregulation of mesenchymal markers and upregulation of epithelial markers. Additionally, honokiol possesses the capability to supress cell migration and invasion via the downregulation of several matrix-metalloproteinases (activation of 5' AMP-activated protein kinase (AMPK) and KISS1/KISS1R signalling), inhibiting cell migration, invasion, and metastasis, as well as inducing anti-angiogenesis activity (via the down-regulation of vascular endothelial growth factor (VEGFR) and vascular endothelial growth factor (VEGF)). Combining these studies provides significant insights for the potential of honokiol to be a promising candidate natural compound for chemoprevention and treatment.

Intestinal oligopeptide transporter PepT1-targeted polymeric micelles for further enhancing the oral absorption of water-insoluble agents

The intestinal epithelium is the main barrier for nanocarriers to orally deliver poorly water-soluble and absorbed agents. To further improve the transmembrane transport efficiency of polymeric micelles, intestinal oligopeptide transporter PepT1-targeted polymeric micelles were fabricated by Gly-Sar-conjugated poly(ethylene glycol)-poly(d,l-lactic acid). The functionalized polymeric micelles with about 40 nm diameter, uniform spherical morphology and favorable cytocompatibility with Caco-2 cells were demonstrated to distinctly enhance the cellular uptake and transmembrane transport of the loaded agents. The results of intestinal absorption strongly evidenced the higher accumulation of the micelles inside the epithelial cells, at the apical and basolateral sides of the epithelium within the villi in mice. Furthermore, the interaction of Gly-Sar decorated polymeric micelles with PepT1 was explored to promote the internalization of the micelles through fluorescence immunoassay, and the PepT1 level on the membrane of Caco-2 cells treated with the micelles appeared to change in a distinctly time-dependent manner. Both clathrin- and caveolae-mediated pathways were involved in the transcellular transport for undecorated polymeric micelles, while the transcellular transport pathway for Gly-Sar decorated ones was changed to be mainly mediated by clathrin and lipid rafts. The colocalization of Gly-Sar decorated micelles with the organelles observed by confocal laser scanning microscopy indicated that late endosomes, lysosomes, endoplasmic reticulum and Golgi apparatus appeared to participate in the intracellular trafficking progression of the micelles. These results suggested that PepT1-targeted polymeric micelles might have a strong potential to greatly promote the oral absorption of poorly water-soluble and absorbed agents.

The role of nanoparticles in the improvement of systemic anticancer drug delivery

The systemic delivery of drugs to the body via circulation after oral administration is a preferred method of drug administration during cancer treatment given its ease of implementation. However, the physicochemical properties of many current anticancer drugs limit their effectiveness when delivered by systemic routes. The use of nanoparticles (NPs) has emerged as an effective means of overcoming the inherent limitations of systemic drug delivery. We provide herein an overview of various NP formulations that facilitate improvements in the efficacy of various anticancer drugs compared with the free drug. This review will be useful to the reader who is interested in the role NP technology is playing in shaping the future of chemotherapeutic drug delivery and disease treatment.

Surface modification of pH-sensitive honokiol nanoparticles based on dopamine coating for targeted therapy of breast cancer

At present, there is a higher demand for the efficacy of nanoparticle drugs. It is hoped that more drugs will reach the tumor site and that the drug will be less harmful to other normal cells of the body before reaching the tumor site. Most target research for nanomedicine can achieve better positioning through complex processes, such as synthesis. To overcome these difficulties, such as the complexity of the preparation method and lack of good targeting, we used simple polydopamine (PDA) as a pH-sensitive targeting anchor for nanoparticles (NPs). We successfully conjugated folic acid (FA) to the surface of honokiol (HK) nanoparticles coated with PDA using a typical surface modifier. After preparation into HK-PDA-FA-NPs, we characterized the particle size, potential and transmission electron microscope (TEM). The targeted nanoparticles (HK-PDA-FA-NPs) can be stably present in various physiological media and exhibit pH sensitivity during drug release in vitro. HK-PDA-FA-NPs have better targeting ability to 4T1 cells than HK-NPs. Targeted nanoparticles have a tumor inhibition rate of greater than 80% in vivo, which is significantly higher than ordinary HK-NPs. This experiment shows that surface modification of HK-NPs coated with PDA is a promising preparation method for targeted therapy.

Development of an interactive tumor vascular suppression strategy to inhibit multidrug resistance and metastasis with pH/H2O2 responsive and oxygen-producing nanohybrids

An ideal cancer therapeutic strategy should not only reverse multidrug resistance (MDR), but also prevent cancer metastasis. In this study, we address these cancer treatment challenges through an interactive vascular suppression strategy.

Co-Delivery Nanosystems for Cancer Treatment: A Review

Massive data available on cancer therapy more than ever lead our mind to the general concept that there is no perfect treatment for cancer. Indeed, the biological complexity of this disease is too excessive to be treated by a single therapeutic approach. Current delivery systems containing a specific drug or gene have their particular opportunities and restrictions. It is worth noting that a considerable number of studies suggest that single- drug delivery systems result in insufficient suppression of cancer growth. Therefore, one of the main ideas of co-delivery system designing is to enhance the intended response or to achieve the synergistic/combined effect compared to the single drug strategy. This review focuses on various strategies for co-delivery of therapeutic agents in the treatment of cancer. The primary approaches within the script are categorized into co-delivery of conventional chemotherapeutics, gene-based molecules, and plant-derived materials. Each one is explained in examples with the recent researches. In the end, a brief summary is provided to conclude the gist of the review.

HSA-based multi-target combination therapy: regulating drugs' release from HSA and overcoming single drug resistance in a breast cancer model

Multi-drug delivery systems, which may be promising solution to overcome obstacles, have limited the clinical success of multi-drug combination therapies to treat cancer. To this end, we used three different anticancer agents, Cu(BpT)Br, NAMI-A, and doxorubicin (DOX), to build human serum albumin (HSA)-based multi-drug delivery systems in a breast cancer model to investigate the therapeutic efficacy of overcoming single drug (DOX) resistance to cancer cells in vivo, and to regulate the drugs' release from HSA. The HSA complex structure revealed that NAMI-A and Cu(BpT)Br bind to the IB and IIA sub-domain of HSA by N-donor residue replacing a leaving group and coordinating to their metal centers, respectively. The MALDI-TOF mass spectra demonstrated that one DOX molecule is conjugated with lysine of HSA by a pH-sensitive linker. Furthermore, the release behavior of three agents form HSA can be regulated at different pH levels. Importantly, in vivo results revealed that the HSA-NAMI-A-Cu(BpT)Br-DOX complex not only increases the targeting ability compared with a combination of the three agents (the NAMI-A/Cu(BpT)Br/DOX mixture), but it also overcomes DOX resistance to drug-resistant breast cancer cell lines.

Synergistically Enhanced Antimetastasis Effects by Honokiol-Loaded pH-Sensitive Polymer-Doxorubicin Conjugate Micelles

In an effort to prevent metastasis of breast tumor cells- at the same time of inhibiting tumor growth with less toxic side effects, honokiol (HNK) was encapsulated into pH-sensitive polymeric micelles based on the conjugate of poly(2-ethyl-2-oxazoline)-poly(d,l-lactide) (PEOz-PLA) with doxorubicin (DOX), denoted as PEOz-PLA-imi-DOX. PEOz-PLA-imi-DOX was successfully synthesized by connecting DOX to the hydrophobic end of PEOz-PLA via acid-cleavable benzoic imine linker. HNK-loaded conjugate micelles (HNK/PP-DOX-PM) with a size of 21 nm and homogeneous spherical shape exhibited high drug-loading capacity. PEOz-PLA-imi-DOX and HNK/PP-DOX-PM displayed faster release of DOX at pH 5.0 than at pH 7.4. As anticipated, PEOz-PLA-imi-DOX maintained cytotoxicity of DOX against MDA-MB-231 cells. The synergistically enhanced in vitro antitumor effect of HNK/PP-DOX-PM was confirmed by their synergetic inhibition of MDA-MB-231 cell growth. Furthermore, the efficient prevention of tumor metastasis by HNK/PP-DOX-PM was testified by in vitro anti-invasion, wound healing and antimigration assessment in MDA-MB-231 cells, and in vivo bioluminescence imaging in nude mice. The suppression of growth and metastasis of tumor cells by HNK/PP-DOX-PM was attributed to the synergistic effect of pH-triggered drug release and HNK-aroused inhibition of matrix metalloproteinases and epithelial-mesenchymal transition, respectively. In addition, HNK/PP-DOX-PM exhibited superior biosafety than physically encapsulated dual-drug micelles. Consequently, the fabricated HNK/PP-DOX-PM may have great potential for safe and effective suppression of tumor growth and metastasis.