Role of generation on folic acid-modified poly(amidoamine) dendrimers for targeted delivery of baicalin to cancer cells

Natural compounds-based nanomedicines for cancer treatment: Future directions and challenges

Several efforts have been extensively accomplished for the amelioration of the cancer treatments using different types of new drugs and less invasives therapies in comparison with the traditional therapeutic modalities, which are widely associated with numerous drawbacks, such as drug resistance, non-selectivity and high costs, restraining their clinical response. The application of natural compounds for the prevention and treatment of different cancer cells has attracted significant attention from the pharmaceuticals and scientific communities over the past decades. Although the use of nanotechnology in cancer therapy is still in the preliminary stages, the application of nanotherapeutics has demonstrated to decrease the various limitations related to the use of natural compounds, such as physical/chemical instability, poor aqueous solubility, and low bioavailability. Despite the nanotechnology has emerged as a promise to improve the bioavailability of the natural compounds, there are still limited clinical trials performed for their application with various challenges required for the pre-clinical and clinical trials, such as production at an industrial level, assurance of nanotherapeutics long-term stability, physiological barriers and safety and regulatory issues. This review highlights the most recent advances in the nanocarriers for natural compounds secreted from plants, bacteria, fungi, and marine organisms, as well as their role on cell signaling pathways for anticancer treatments. Additionally, the clinical status and the main challenges regarding the natural compounds loaded in nanocarriers for clinical applications were also discussed.

A Multifunctional Liposome for Synergistic Chemotherapy with Ferroptosis Activation of Triple-Negative Breast Cancer

There is an urgent need to develop efficient treatments for highly invasive triple-negative breast cancer (TNBC) with a high rate of postoperative. Baicalin (BA) has shown inhibitory effects on several tumor cells and could activate ferroptosis in some tumor cells by producing reactive oxygen species (ROS). For overcoming the shortcomings of BA in clinical applications and enhancing the effect of ferroptosis in TNBC, herein, a multifunctional liposome (BA-Fe(III) coordination-polymer-loaded liposome, BA-Fe(III) Lipo) was developed for synergistic chemotherapy of TNBC with ferroptosis activation. Fe(III) released from BA-Fe(III) Lipo could be efficiently reduced to Fe(II) in the presence of high glutathione in tumor microenvironment, which in turn catalyzed the oxidation of unsaturated fats through lipid peroxidation for more ROS production. In addition, BA-Fe(III) Lipo activated tumor cell ferroptosis by down-regulating the enzymatic activity of ferritin heavy chain 1 protein and glutathione peroxidase. This study provided a novel therapeutic strategy for the treatment of TNBC by ingeniously combining chemotherapy with the activation of ferroptosis, which presented potential clinical applications.

Engineered extracellular vesicles: A new approach for targeted therapy of tumors and overcoming drug resistance

Targeted delivery of anti-tumor drugs and overcoming drug resistance in malignant tumor cells remain significant clinical challenges. However, there are only few effective methods to address these issues. Extracellular vesicles (EVs), actively secreted by cells, play a crucial role in intercellular information transmission and cargo transportation. Recent studies have demonstrated that engineered EVs can serve as drug delivery carriers and showed promising application prospects. Nevertheless, there is an urgent need for further improvements in the isolation and purification of EVs, surface modification techniques, drug assembly processes, and precise recognition of tumor cells for targeted drug delivery purposes. In this review, we summarize the applications of engineered EVs in cancer treatment and overcoming drug resistance, and current challenges associated with engineered EVs are also discussed. This review aims to provide new insights and potential directions for utilizing engineered EVs as targeted delivery systems for anti-tumor drugs and overcoming drug resistance in the near future.

Baicalin functionalized PEI-heparin carbon dots as cancer theranostic agent

The worldwide prevalence of cancer and its significantly rising risks with age have garnered the attention of nanotechnology for prompt detection and effective therapy with minimal or no adverse effects. In the current study, heparin (HP) polymer derived heteroatom (N, S-) co-doped CDs were synthesized using hydrothermal synthesis method to efficiently deliver natural anticancer compound baicalin (BA). Heparin carbon dots (HCDs) were passivated with polyethylenimine (PEI) to improve its fluorescence quantum yield. The surface passivation of CDs by polycationic PEI polymer not only facilitated loading of BA, but also played a crucial role in the pH-responsive drug delivery. The sustained release of BA (up to 80 %) in mildly acidic pH (5.5 and 6.5) conditions endorsed its drug delivery potential for cancer-specific microenvironments. BA-loaded PHCDs exhibited enhanced anticancer activity as compared to BA/PHCDs indicating the effectiveness of the nanoformulation, Furthermore, the flow cytometry analysis confirmed that BA-PHCDs treated cells were arrested in the G2/M phase of cell cycle and had a higher potential for apoptosis. Bioimaging study demonstrated the excellent cell penetration efficiency of PHCDs with complete cytoplasmic localization. All this evidence comprehensively demonstrates the potency of BA-loaded PHCDs as a nanotheranostic agent for cancer.

Glycyrrhetinic Acid Receptor-Mediated Zeolitic Imidazolate Framework-8 Loaded Doxorubicin as a Nanotherapeutic System for Liver Cancer Treatment

In this study, we designed and developed a DOX nanodrug delivery system (PEG-GA@ZIF-8@DOX) using ZIF-8 as the carrier and glycyrrhetinic acid (GA) as the targeting ligand. We confirmed that DOX was loaded and PEG-GA was successfully modified on the surface of the nanoparticles. The in vitro release profile of the system was investigated at pH 5.0 and 7.4. The cellular uptake, in vitro cytotoxicity, and lysosomal escape characteristics were examined using HepG2 cells. We established an H22 tumor-bearing mouse model and evaluated the in vivo antitumor activity. The results showed that the system had a uniform nanomorphology. The drug loading capacity was 11.22 ± 0.87%. In acidic conditions (pH 5.0), the final release rate of DOX was 57.73%, while at pH 7.4, it was 25.12%. GA-mediated targeting facilitated the uptake of DOX by the HepG2 cells. PEG-GA@ZIF-8@DOX could escape from the lysosomes and release the drug in the cytoplasm, thus exerting its antitumor effect. When the in vivo efficacy was analyzed, we found that the tumor inhibition rate of PEG-GA@ZIF-8@DOX was 67.64%; it also alleviated the loss of the body weight of the treated mice. This drug delivery system significantly enhanced the antitumor effect of doxorubicin in vitro and in vivo, while mitigating its toxic side effects.

Exploring the efficacy of herbal medicinal products as oral therapy for inflammatory bowel disease

Inflammatory bowel disease (IBD) encompasses a collection of idiopathic diseases characterized by chronic inflammation in the gastrointestinal (GI) tract. Patients diagnosed with IBD often experience necessitate long-term pharmacological interventions. Among the multitude of administration routes available for treating IBD, oral administration has gained significant popularity owing to its convenience and widespread utilization. In recent years, there has been extensive evaluation of the efficacy of orally administered herbal medicinal products and their extracts as a means of treating IBD. Consequently, substantial evidence has emerged, supporting their effectiveness in IBD treatment. This review aimed to provide a comprehensive summary of recent studies evaluating the effects of herbal medicinal products in the treatment of IBD. We delved into the regulatory role of these products in modulating immunity and maintaining the integrity of the intestinal epithelial barrier. Additionally, we examined their impact on antioxidant activity, anti-inflammatory properties, and the modulation of intestinal flora. By exploring these aspects, we aimed to emphasize the significant advantages associated with the use of oral herbal medicinal products in the treatment of IBD. Of particular note, this review introduced the concept of herbal plant-derived exosome-like nanoparticles (PDENs) as the active ingredient in herbal medicinal products for the treatment of IBD. The inclusion of PDENs offers distinct advantages, including enhanced tissue penetration and improved physical and chemical stability. These unique attributes not only demonstrate the potential of PDENs but also pave the way for the modernization of herbal medicinal products in IBD treatment.

Dendrimers as Nanocarriers for the Delivery of Drugs Obtained from Natural Products

Natural products have proven their value as drugs that can be therapeutically beneficial in the treatment of various diseases. However, most natural products have low solubility and poor bioavailability, which pose significant challenges. To solve these issues, several drug nanocarriers have been developed. Among these methods, dendrimers have emerged as vectors for natural products due to their superior advantages, such as a controlled molecular structure, narrow polydispersity index, and the availability of multiple functional groups. This review summarizes current knowledge on the structures of dendrimer-based nanocarriers for natural compounds, with a particular focus on applications in alkaloids and polyphenols. Additionally, it highlights the challenges and perspectives for future development in clinical therapy.

Recent advances in flavonoid-based nanocarriers as an emerging drug delivery approach for cancer chemotherapy

Flavonoids are an interesting class of biomolecules, which exhibit cancer-inhibitory effects through both chemopreventive and chemotherapeutic activities. However, their therapeutic efficacy is affected by poor pharmacokinetics (PK) and biopharmaceutical attributes. One of the most promising approaches to resolve these issues is to formulate flavonoids in nanosystems. Different flavonoid nanoformulations have shown therapeutic superiority over free flavonoids. Functionalization of nanoparticles (NPs) further improves their therapeutic efficacy by facilitating site-specific delivery and reducing nonspecific toxicities. In this review, we highlight recent developments in the field of flavonoid-based NPs to gain translational insights into the potential applications of flavonoid-based nanocarriers in cancer management.

Flavonoids-Based Delivery Systems towards Cancer Therapies

Cancer is the second leading cause of death worldwide. Cervical cancer, for instance, is considered a major scourge in low-income countries. Its development is mostly associated with the human papillomavirus persistent infection and despite the availability of preventive vaccines, they are only widely administered in more developed countries, thus leaving a large percentage of unvaccinated women highly susceptible to this type of cancer. Current treatments are based on invasive techniques, being far from effective. Therefore, the search for novel, advanced and personalized therapeutic approaches is imperative. Flavonoids belong to a group of natural polyphenolic compounds, well recognized for their great anticancer capacity, thus promising to be incorporated in cancer therapy protocols. However, their use is limited due to their low solubility, stability and bioavailability. To surpass these limitations, the encapsulation of flavonoids into delivery systems emerged as a valuable strategy to improve their stability and bioavailability. In this context, the aim of this review is to present the most reliable flavonoids-based delivery systems developed for anticancer therapies and the progress accomplished, with a special focus on cervical cancer therapy. The gathered information revealed the high therapeutic potential of flavonoids and highlights the relevance of delivery systems application, allowing a better understanding for future studies on effective cancer therapy.

Smart poly(amidoamine) dendron-functionalized magnetic graphene oxide for cancer therapy

A novel multicomponent magnetic nanocomposite whose drug release behavior is pH and temperature dependent.

Novel bioemulsomes for baicalin oral lymphatic targeting: development, optimization and pharmacokinetics

Aim: The aim of this study was to elaborate on 'bioemulsomes,' novel biocompatible lipoprotein analogs for effective lymphatic transport of baicalin (BCL). Methods: BCL bioemulsomes were developed and optimized and in vitro physicochemical characterization performed. The bioavailability of BCL bioemulsomes compared with free BCL was investigated using in vivo pharmacokinetics studies. Finally, BCL lymphatic transport was assessed via cycloheximide blockade assay. Results: Optimized BCL-loaded nanoemulsomes showed promising in vitro characteristics that favor lymphatic targeting. In vivo pharmacokinetics showed a significant improvement in bioavailability over free BCL. A significant decrease in BCL emulsome absorption (33%) was exhibited after chemical blockage of the lymphatic pathway, confirming the lymphatic transport potential. Conclusion: Bioemulsomes could be a promising tool for bypassing BCL oral delivery hurdles as well as lymphatic transport, paving the way for potential treatment of lymphoma.

Biotinylated Mn3O4 nanocuboids for targeted delivery of gemcitabine hydrochloride to breast cancer and MRI applications

Multifunctional nanocarriers have been found as potential candidate for the targeted drug delivery and imaging applications. Herein, we have developed a biocompatible and pH-responsive manganese oxide nanocuboid system, surface modified with poly (ethylene glycol) bis(amine) and functionalized with biotin (Biotin-PEG-MNCs), for an efficient and targeted delivery of an anticancer drug (gemcitabine, GEM) to the human breast cancer cells. GEM-loaded Biotin-PEG@MNCs showed high drug loading efficiency, controlled release of GEM and excellent storage stability in the physiological buffers and different temperature conditions. GEM-loaded Biotin-PEG@MNCs showed dose- and time-dependent decrease in the viability of human breast cancer cells. Further, it exhibited significantly higher cell growth inhibition than pure GEM which suggested that Biotin-PEG@MNCs has efficiently delivered the GEM into cancerous cells. The role of biotin in the uptake was proved by the competitive binding-based cellular uptake study. A significant decrease in the amount of manganese was observed in biotin pre-treated cancer cells as compared to biotin untreated cancer cells. In MRI studies, Biotin-PEG-MNCs showed both longitudinal and transverse relaxivity about 0.091 and 7.66 mM^-1 s^-1 at 3.0 T MRI scanner, respectively. Overall, the developed Biotin-PEG-MNCs presents a significant potential in formulation development for cancer treatment via targeted drug delivery and enhanced MRI contrast imaging properties.

There and back again: a dendrimer's tale

The development of molecular nanostructures with well-defined particle size and shape is of eminent interest in biomedicine. Among many studied nanostructures, dendrimers represent the group of those most thoroughly characterized ones. Due to their unique structure and properties, dendrimers are very attractive for medical and pharmaceutical applications. Owing to the controllable cavities inside the dendrimer, guest molecules may be encapsulated, and highly reactive terminal groups are susceptible to further modifications, e.g., to facilitate target delivery. To understand the potential of these nanoparticles and to predict and avoid any adverse cellular reactions, it is necessary to know the mechanisms responsible for an efficient dendrimer uptake and the destination of their intracellular journey. In this article, we summarize the results of studies describing the dendrimer uptake, traffic, and efflux mechanisms depending on features of specific nanoparticles and cell types. We also present mechanisms of dendrimers responsible for toxicity and alteration in signal transduction pathways at the cellular level.

Non-invasive intranasal administration route directly to the brain using dendrimer nanoplatforms: An opportunity to develop new CNS drugs

There are several routes of administration to the brain, including intraparenchymal, intraventricular, and subarachnoid injections. The blood-brain barrier (BBB) impedes the permeation and access of most drugs to the central nervous system (CNS), and consequently, many neurological diseases remain undertreated. For past decades, to circumvent this effect, several nanocarriers have been developed to deliver drugs to the brain. Importantly, intranasal (IN) administration can allow direct delivery of drugs into the brain through the anatomical connection between the nasal cavity and brain without crossing the BBB. In this regard, dendrimers may possess great potential to deliver drugs to the brain by IN administration, bypassing the BBB and reducing systemic exposure and side effects, to treat diseases of the CNS. In this original concise review, we highlighted the few examples advocated regarding the use of dendrimers to deliver CNS drugs directly via IN. This review highlighed the few examples of the association of dendrimer encapsulating drugs (e.g., small compounds: haloperidol and paeonol; macromolecular compounds: dextran, insulin and calcitonin; and siRNA) using IN administration. Good efficiencies were observed. In addition, we will present the in vivo effects of PAMAM dendrimers after IN administration, globally, showing no general toxicity.

Baicalin mediated regulation of key signaling pathways in cancer

Baicalin has been widely investigated against different types of malignancies both at the cellular and molecular levels over the past few years. Due to its remarkable anti-proliferative potential in numerous cancer cell lines, it has created immense interest as a potential chemotherapeutic modality compared to other flavonoids. Thus, this review focuses on the recent accomplishments of baicalin and its limitations in cancer prevention and treatment. Further, combination studies and nanoformulations using baicalin to treat cancer along with the metabolism, bioavailability, toxicity, and pharmacokinetics have been discussed. The present review explains biological source, and anti-proliferative potential of baicalin against cancers including breast, colon, hepatic, leukemia, lung, and skin, as well as the relevant mechanism of action to modulate diverse signaling pathways including apoptosis, cell cycle, invasion, and migration, angiogenesis, and autophagy. The anticancer mechanism of baicalin in orthotropic and xenograft mice models have been deliberated. The combination studies of baicalin in novel therapies as chemotherapeutic adjuvants have also been summarized. The low bioavailability, fast metabolism, and poor solubility, and other significant factors that limit the clinical use of baicalin have been examined as a challenge. The improvement in the pharmacokinetics and pharmacodynamics of baicalin with newer approaches and the gaps are highlighted, which could establish baicalin as an effective and safe compound for cancer treatment as well as help to translate its potential from bench to bedside.

Baicalin Regulates Proliferation, Apoptosis, Migration, and Invasion in Mesothelioma

Background

Baicalin, one of the main bioactive components extracted from the traditional Chinese medicine baical Skullcap root, has an anti-tumor activity which had been studied in several cancers. However, its role in human mesothelioma remains unknown. In this study, we investigated the anti-tumor mechanisms of baicalin in the mesothelioma cell line MESO924.

Material/Methods

Effects of baicalin on mesothelioma were assessed by measuring cell viability, apoptosis, migration, invasion, inactivation of signaling intermediates, and cell-cycle alterations.

Results

Baicalin inhibited the proliferation, migration, and invasion of human mesothelioma cells and increased their apoptosis, all in a dose-dependent manner. Specifically, baicalin decreased the expression of p-EGFR, p-AKT, p-MAPK, p-S6, Bcl-2, and VEGF and increased the expression of Bax in mesothelioma cells. The suppressed mesothelioma cellular proliferation is due to the arrest of the S cell cycle by baicalin. Inhibition of the PI3K/AKT/mTOR signaling pathway by a PI3K/AKT/mTOR inhibitor augmented the anti-proliferation effects induced by baicalin. In addition, baicalin increased the sensitivity of MESO924 to the chemotherapeutic drugs doxorubicin, cisplatin, and pemetrexed.

Conclusions

These results highlight the roles of baicalin in inhibiting cell growth, migration, and invasion of mesothelioma cells while increasing apoptosis and sensitizing cells to chemotherapeutic agents through the PI3K/AKT/mTOR signaling pathway, which indicates that baicalin could be a useful drug for mesothelioma therapy.

Current trends and challenges in cancer management and therapy using designer nanomaterials

Nanotechnology has the potential to circumvent several drawbacks of conventional therapeutic formulations. In fact, significant strides have been made towards the application of engineered nanomaterials for the treatment of cancer with high specificity, sensitivity and efficacy. Tailor-made nanomaterials functionalized with specific ligands can target cancer cells in a predictable manner and deliver encapsulated payloads effectively. Moreover, nanomaterials can also be designed for increased drug loading, improved half-life in the body, controlled release, and selective distribution by modifying their composition, size, morphology, and surface chemistry. To date, polymeric nanomaterials, metallic nanoparticles, carbon-based materials, liposomes, and dendrimers have been developed as smart drug delivery systems for cancer treatment, demonstrating enhanced pharmacokinetic and pharmacodynamic profiles over conventional formulations due to their nanoscale size and unique physicochemical characteristics. The data present in the literature suggest that nanotechnology will provide next-generation platforms for cancer management and anticancer therapy. Therefore, in this critical review, we summarize a range of nanomaterials which are currently being employed for anticancer therapies and discuss the fundamental role of their physicochemical properties in cancer management. We further elaborate on the topical progress made to date toward nanomaterial engineering for cancer therapy, including current strategies for drug targeting and release for efficient cancer administration. We also discuss issues of nanotoxicity, which is an often-neglected feature of nanotechnology. Finally, we attempt to summarize the current challenges in nanotherapeutics and provide an outlook on the future of this important field.

An Available Strategy for Nasal Brain Transport of Nanocomposite Based on PAMAM Dendrimers via In Situ Gel

Polyamidoamine (PAMAM) dendrimers are efficient drug carriers. The presence of a physiological pathway for nasal brain transport provides a potential path for direct brain-targeted delivery of dendrimer nanocomposites. In this study, we synthesized PAMAM dendrimer composites with a nanoscale size; the particle size of PAE (Paeonol)/mPEG (the heterofunctional PEG polymer with a methoxy)-PAMAM G5.NHAc and mPEG-PAMAM G5.NH₂-FITC were 72.41 ± 11.58 nm and 96.51 ± 7.77 nm, and the zeta potential of PAE/mPEG-PAMAM G5.NHAc and mPEG-PAMAM G5.NH₂-FITC were + 0.57 ± 0.11 mv and + 9.60 ± 0.41 mv, respectively. The EE% and DL% of PAE in PAE/mPEG-PAMAM G5.NHAc were 53.77% and 13.92%, respectively. PAE/mPEG-PAMAM G5.NHAc/DGG ionic-sensitive in situ gel was prepared, the viscosity of solution and gel state were 112 ± 3.2 mPa and 1403 ± 38.5 mPa, respectively. The in vitro goat mucoadhesive strength of the gel was 4763.36 ± 85.39 dyne/cm². In situ gel system was proven to be a non-Newtonian pseudo-plastic fluid with shear thinning, thixotropy and yield stress. The optimal model of PAE released from PAE/mPEG-PAMAM G5.NHAc and PAE/mPEG-PAMAM G5.NHAc/DGG were the Higuchi equation and the Korsmeyer-Peppas equation, respectively. The cytotoxicity of the nanocomposites showed a concentration-dependence, and the cell viabilities of PAE/mPEG-PAMAM G5.NHAc were both higher than 95% between 0.0001 μM and 10 μM. mPEG-PAMAM G5.NH₂-FITC was efficiently taken up by cells and exhibited strong fluorescence in the cytoplasm and nucleus. Significant accumulation of nanocomposites was observed in the brain after administration of the in situ gel group, and maximum accumulation was reached at 12 h. A small amount of accumulation was observed in the nanocomposite solution group only at 2 h. Therefore, the direct nasal brain transport efficiency of PAMAM dendrimer nanocomposites can be significantly improved after combining with in situ gel. PAMAM dendrimer nanocomposite/DGG is a potential drug delivery system for nasal brain transport.

Synthesis and potent cytotoxic activity of a novel diosgenin derivative and its phytosomes against lung cancer cells

Diosgenin (Di), a steroidal sapogenin derived from plants, has been shown to exert anticancer effects in preclinical studies. Using Di as a starting material, various Di derivatives were designed and synthesized, aiming to discover new steroid-based antitumor agents. In this work, we synthesized several Di derivatives and screened FZU-0021-194-P2 (P2), which showed more potent cytotoxic activities against human non-small-cell lung cancer A549 and PC9 cells. Considering that Di has a unique sterol structure similarly to cholesterol, P2 phytosomes (P2Ps) were prepared to further improve the water solubility of P2. The P2Ps exhibited a particle size of 53.6 ± 0.3 nm with oval shape and a zeta potential of -4.0 ± 0.7 mV. P2Ps could inhibit the proliferation of lung cancer cells more efficiently than Di phytosomes after 72 h of incubation time by inducing cell cycle arrest and apoptosis. The results indicated that P2Ps could be a promising anticancer formulation for non-small-cell lung cancer.

Targeting Groups Employed in Selective Dendrons and Dendrimers

The design of compounds with directed action to a defined organ or tissue is a very promising approach, since it can decrease considerably the toxicity of the drug/bioactive compound. For this reason, this kind of strategy has been greatly important in the scientific community. Dendrimers, on the other hand, comprise extremely organized macromolecules with many peripheral functionalities, stepwise controlled synthesis, and defined size. These nanocomposites present several biological applications, demonstrating their efficiency to act in the pharmaceutical field. Considering that, the main purpose of this review was describing the potential of dendrons and dendrimers as drug targeting, applying different targeting groups. This application has been demonstrated through interesting examples from the literature considering the last ten years of publications.

MicroRNAs delivery into human cells grown on 3D-printed PLA scaffolds coated with a novel fluorescent PAMAM dendrimer for biomedical applications

Many advanced synthetic, natural, degradable or non-degradable materials have been employed to create scaffolds for cell culture for biomedical or tissue engineering applications. One of the most versatile material is poly-lactide (PLA), commonly used as 3D printing filament. Manufacturing of multifunctional scaffolds with improved cell growth proliferation and able to deliver oligonucleotides represents an innovative strategy for controlled and localized gene modulation that hold great promise and could increase the number of applications in biomedicine. Here we report for the first time the synthesis of a novel Rhodamine derivative of a poly-amidoamine dendrimer (G = 5) able to transfect cells and to be monitored by confocal microscopy that we also employed to coat a 3D-printed PLA scaffold. The coating do not modify the oligonucleotide binding ability, toxicity or transfection properties of the scaffold that is able to increase cell proliferation and deliver miRNA mimics (i.e., pre-mir-503) into human cells. Although further experiments are required to optimize the dendrimer/miRNA ratio and improve transfection efficiency, we demonstrated the effectiveness of this promising and innovative 3D-printed transfection system to transfer miRNAs into human cells for future biomedical applications.

Acetal-Linked Paclitaxel Polymeric Prodrug Based on Functionalized mPEG-PCL Diblock Polymer for pH-Triggered Drug Delivery

The differences in micro-environment between cancer cells and the normal ones offer the possibility to develop stimuli-responsive drug-delivery systems for overcoming the drawbacks in the clinical use of anticancer drugs, such as paclitaxel, doxorubicin, and etc. Hence, we developed a novel endosomal pH-sensitive paclitaxel (PTX) prodrug micelles based on functionalized poly(ethylene glycol)-poly(ε-caprolactone) (mPEG-PCL) diblock polymer with an acid-cleavable acetal (Ace) linkage (mPEG-PCL-Ace-PTX). The mPEG-PCL-Ace-PTX₅ with a high drug content of 23.5 wt % was self-assembled in phosphate buffer (pH 7.4, 10 mM) into nanosized micelles with an average diameter of 68.5 nm. The in vitro release studies demonstrated that mPEG-PCL-Ace-PTX₅ micelles was highly pH-sensitive, in which 16.8%, 32.8%, and 48.2% of parent free PTX was released from mPEG-PCL-Ace-PTX₅ micelles in 48 h at pH 7.4, 6.0, and 5.0, respectively. Thiazolyl Blue Tetrazolium Bromide (MTT) assays suggested that the pH-sensitive PTX prodrug micelles displayed higher therapeutic efficacy against MCF-7 cells compared with free PTX. Therefore, the PTX prodrug micelles with acetal bond may offer a promising strategy for cancer therapy.

Recent Advances in Nanoparticle-Based Cancer Drug and Gene Delivery

Effective and safe delivery of anticancer agents is among the major challenges in cancer therapy. The majority of anticancer agents are toxic to normal cells, have poor bioavailability, and lack in vivo stability. Recent advancements in nanotechnology provide safe and efficient drug delivery systems for successful delivery of anticancer agents via nanoparticles. The physicochemical and functional properties of the nanoparticle vary for each of these anticancer agents, including chemotherapeutics, nucleic acid-based therapeutics, small molecule inhibitors, and photodynamic agents. The characteristics of the anticancer agents influence the design and development of nanoparticle carriers. This review focuses on strategies of nanoparticle-based drug delivery for various anticancer agents. Recent advancements in the field are also highlighted, with suitable examples from our own research efforts and from the literature.