Paclitaxel-loaded micelles enhance transvascular permeability and retention of nanomedicines in tumors

A Comprehensive Review on Current Treatments and Challenges Involved in the Treatment of Ovarian Cancer

Ovarian cancer (OC) is the second most common gynaecological malignancy. It typically affects females over the age of 50, and since 75% of cases are only discovered at stage III or IV, this is a sign of a poor diagnosis. Despite intraperitoneal chemotherapy's chemosensitivity, most patients relapse and face death. Early detection is difficult, but treatment is also difficult due to the route of administration, resistance to therapy with recurrence, and the need for precise cancer targeting to minimize cytotoxicity and adverse effects. On the other hand, undergoing debulking surgery becomes challenging, and therapy with many chemotherapeutic medications has manifested resistance, a condition known as multidrug resistance (MDR). Although there are other therapeutic options for ovarian cancer, this article solely focuses on co-delivery techniques, which work via diverse pathways to overcome cancer cell resistance. Different pathways contribute to MDR development in ovarian cancer; however, usually, pump and non-pump mechanisms are involved. Striking cancerous cells from several angles is important to defeat MDR. Nanocarriers are known to bypass the drug efflux pump found on cellular membranes to hit the pump mechanism. Nanocarriers aid in the treatment of ovarian cancer by enhancing the delivery of chemotherapeutic drugs to the tumour sites through passive or active targeting, thereby reducing unfavorable side effects on the healthy tissues. Additionally, the enhanced permeability and retention (EPR) mechanism boosts the bioavailability of the tumour site. To address the shortcomings of conventional delivery, the current review attempts to explain the current conventional treatment with special reference to passively and actively targeted drug delivery systems (DDSs) towards specific receptors developed to treat ovarian cancer. In conclusion, tailored nanocarriers would optimize medication delivery into the intracellular compartment before optimizing intra-tumour distribution. Other novel treatment possibilities for ovarian cancer include tumour vaccines, gene therapy, targeting epigenetic alteration, and biologically targeted compounds. These characteristics might enhance the therapeutic efficacy.

Development and Evaluation of Polymeric Mixed Micelles Prepared using Hot-Melt Extrusion for Extended Delivery of Poorly Water-Soluble Drugs

The poor aqueous solubility is a well-recognized restriction for the clinical application of many drug molecules. Micelles delivery system provides a promising strategy for the solubility enhancement of hydrophobic drugs. This study developed and evaluated different polymeric mixed micelles prepared using hot-melt extrusion coupled hydration method to improve the solubility and extend the release of the model drug ibuprofen (IBP). The physicochemical properties of the prepared formulations were characterized in terms of particle size, polydispersity index, zeta potential, surface morphology, crystallinity, encapsulation efficiency, drug content, in vitro drug release, dilution stability, and storage stability. Soluplus®/poloxamer 407, Soluplus®/poloxamer 188, and Soluplus®/TPGS mixed micelles had average particle sizes of 86.2 ± 2.8, 89.6 ± 4.2, and 102.5 ± 3.13 nm, respectively with adequate encapsulation efficiencies of 80% to 92%. Differential scanning calorimetry studies confirmed that the IBP molecules were dissolved in the polymers in an amorphous state. The in vitro release results revealed that the IBP-loaded mixed micelles presented extended-release behavior compared to the free drug. In addition, the developed polymeric mixed micelles remained stable upon dilution and one-month storage. These results demonstrated that the hot-melt extrusion coupling hydration method could be a promising, effective, and environment-friendly manufacturing technique for the scale-up production of polymeric mixed micelles to deliver insoluble drugs.

Polymeric Nanoparticles for Delivery of Natural Bioactive Agents: Recent Advances and Challenges

In the last few decades, several natural bioactive agents have been widely utilized in the treatment and prevention of many diseases owing to their unique and versatile therapeutic effects, including antioxidant, anti-inflammatory, anticancer, and neuroprotective action. However, their poor aqueous solubility, poor bioavailability, low GIT stability, extensive metabolism as well as short duration of action are the most shortfalls hampering their biomedical/pharmaceutical applications. Different drug delivery platforms have developed in this regard, and a captivating tool of this has been the fabrication of nanocarriers. In particular, polymeric nanoparticles were reported to offer proficient delivery of various natural bioactive agents with good entrapment potential and stability, an efficiently controlled release, improved bioavailability, and fascinating therapeutic efficacy. In addition, surface decoration and polymer functionalization have opened the door to improving the characteristics of polymeric nanoparticles and alleviating the reported toxicity. Herein, a review of the state of knowledge on polymeric nanoparticles loaded with natural bioactive agents is presented. The review focuses on frequently used polymeric materials and their corresponding methods of fabrication, the needs of such systems for natural bioactive agents, polymeric nanoparticles loaded with natural bioactive agents in the literature, and the potential role of polymer functionalization, hybrid systems, and stimuli-responsive systems in overcoming most of the system drawbacks. This exploration may offer a thorough idea of viewing the polymeric nanoparticles as a potential candidate for the delivery of natural bioactive agents as well as the challenges and the combating tools used to overcome any hurdles.

Development of Drug Carriers with Biocompatibility Based On Human Serum Albumin and β-Cyclodextrin Molecules and Study of Anticancer Activity

Herein, a novel molecule S4, which could form a uniform S4 spherical aggregate in water, was synthesized, and the S4 aggregate was used to load Dox to prepare the S4@Dox nanomedicine. The loading efficiency was 80.0 ± 4.5%. The pH response and slow release of Dox were the typical characteristics of the S4@Dox nanomedicine. In vitro experiments showed that cancer cells could successfully phagocytose S4 aggregates and the S4@Dox nanomedicine. The toxicity of S4 aggregates to MCF-7, HepG2, and H22 cells was low, and the S4@Dox nanomedicine had better antitumor activity and specific targeting, especially to the MCF-7 cells. The antitumor activity in vivo and in the tissue section showed that the S4@Dox nanomedicine could significantly reduce Dox toxicity, effectively induce the apoptosis of cancer cells, and effectively inhibit tumor growth, which showed that the nanomedicine had better antitumor activity.

Engineering nanomedicines to inhibit hypoxia-inducible Factor-1 for cancer therapy

Hypoxia-inducible factor-1 (HIF-1), an essential promoter of tumor progression, has attracted increasing attention as a therapeutic target. In addition to hypoxic cellular conditions, HIF-1 activation can be triggered by cancer treatment, which causes drug tolerance and therapeutic failure. To date, a series of effective strategies have been explored to suppress HIF-1 function, including silencing the HIF-1α gene, inhibiting HIF-1α protein translation, degrading HIF-1α protein, and inhibiting HIF-1 transcription. Furthermore, nanoparticle-based drug delivery systems have been widely developed to improve the stability and pharmacokinetics of HIF-1 inhibitors or achieve HIF-1-targeted combination therapies as a nanoplatform. In this review, we summarize the current literature on nanomedicines targeting HIF-1 to combat cancer and discuss their potential for future development.

Conquering the Hypoxia Limitation for Photodynamic Therapy

Photodynamic therapy (PDT) has aroused great research interest in recent years owing to its high spatiotemporal selectivity, minimal invasiveness, and low systemic toxicity. However, due to the hypoxic nature characteristic of many solid tumors, PDT is frequently limited in therapeutic effect. Moreover, the consumption of O₂ during PDT may further aggravate the tumor hypoxic condition, which promotes tumor proliferation, metastasis, and invasion resulting in poor prognosis of treatment. Therefore, numerous efforts have been made to increase the O₂ content in tumor with the goal of enhancing PDT efficacy. Herein, these strategies developed in past decade are comprehensively reviewed to alleviate tumor hypoxia, including 1) delivering exogenous O₂ to tumor directly, 2) generating O₂ in situ, 3) reducing tumor cellular O₂ consumption by inhibiting respiration, 4) regulating the TME, (e.g., normalizing tumor vasculature or disrupting tumor extracellular matrix), and 5) inhibiting the hypoxia-inducible factor 1 (HIF-1) signaling pathway to relieve tumor hypoxia. Additionally, the O₂ -independent Type-I PDT is also discussed as an alternative strategy. By reviewing recent progress, it is hoped that this review will provide innovative perspectives in new nanomaterials designed to combat hypoxia and avoid the associated limitation of PDT.

Regulating the uptake of poly(N-(2-hydroxypropyl) methacrylamide)-based micelles in cells cultured on micropatterned surfaces

Cellular uptake of nanoparticles plays a crucial role in cell-targeted biomedical applications. Despite abundant studies trying to understand the interaction between nanoparticles and cells, the influence of cell geometry traits such as cell spreading area and cell shape on the uptake of nanoparticles remains unclear. In this study, poly(vinyl alcohol) is micropatterned on polystyrene cell culture plates using ultraviolet photolithography to control the spreading area and shape of individual cells. The effects of these factors on the cellular uptake of poly(N-(2-hydroxypropyl)methacrylamide)-based micelles were investigated at a single-cell level. Human carcinoma MCF-7 and A549 cells as well as normal Hs-27 and MRC-5 fibroblasts were cultured on micropatterned surfaces. MCF-7 and A549 cells, both with larger sizes, had a higher total micelle uptake. However, the uptake of Hs-27 and MRC-5 cells decreased with increasing spreading area. In terms of cell shapes, MCF-7 and A549 cells with round shapes showed a higher micelle uptake, while those with a square shape had a lower cellular uptake. On the other hand, Hs-27 and MRC-5 cells showed opposite behaviors. The results indicate that the geometry of cells can influence the nanoparticle uptake and may shed light on the design of functional nanoparticles.

Triptolide delivery: Nanotechnology-based carrier systems to enhance efficacy and limit toxicity

Triptolide (TP) possesses a wide range of biological and pharmacological activities involved in the treatment of various diseases. However, widespread usages of TP raise the urgent issues of the severe toxicity, which hugely limits its further clinical application. The novel functional nanostructured delivery system, which is of great significance in enhancing the efficacy, reducing side effects and improving bioavailability, could improve the enrichment, penetration and controlled release of drugs in the lesion location. Over the past decades, considerable efforts have been dedicated to designing and developing a variety of TP delivery systems with the intention of alleviating the adverse toxicity effects and enhancing the bioavailability. In this review, we briefly summarized and discussed the recent functionalized nano-TP delivery systems for the momentous purpose of guiding further development of novel TP delivery systems and providing perspectives for future clinical applications.

Gadolinium-loaded calcium phosphate nanoparticles for magnetic resonance imaging of orthotopic hepatocarcinoma and primary hepatocellular carcinoma

The development of magnetic resonance imaging (MRI) contrast agents with high sensitivity and good biocompatibility is of great value for the diagnosis of primary hepatocellular carcinoma (HCC). Here, a novel MRI contrast agent based on calcium phosphate (CaP) nanoparticles modified with a liver cancer cell targeting peptide A54 (A54-CaP) was fabricated. The T1-positive contrast agent Gd-DTPA was encapsulated inside the nanoparticles (A54-CaPNPs), with a mean diameter of 30 nm and a high encapsulation efficiency of 92.73%. The A54-CaPNP solution exhibited higher longitudinal relaxivity (6.07 mM-1 s-1) than that of the clinically used MRI contrast agent Gd-DTPA (3.56 mM-1 s-1). A much higher accumulation of the nanoparticles in the liver cells was observed, which was directed by the A54 targeting peptide. Furthermore, the MRI diagnostic efficiency of A54-CaPNPs was systematically investigated in an orthotopic liver cancer model and primary HCC model. In vivo MRI experiments showed that A54-CaPNPs had higher sensitivity in the BEL-7402 orthotopic liver cancer model with a more remarkable contrast enhancement and a longer imaging time compared to those without A54 modification. Moreover, the experiments on primary HCC models suggested that A54-CaPNPs showed greatly enhanced MR imaging performance in comparison with Gd-DTPA. These results suggest that A54-CaPNPs possess great potential to enable the non-invasive early diagnosis of primary HCC for timely surgical resection.

Polymer-hybrid nanoparticles: Current advances in biomedical applications

The unique properties of polymer-hybrid nanosystems enable them to play an important role in different fields such as biomedical applications. Hybrid materials, which are formed by polymer and inorganic- or organic-base systems, have been the focus of many recently published studies whose results have shown outstanding improvements in drug targeting. The development of hybrid polymer materials can avoid the synthesis of new molecules, which is an overall expensive process that can take several years to get to the proper elaboration and approval. Thus, the combination of properties in a single hybrid system can have several advantages over non-hybrid platforms, such as improvements in circulation time, structural disintegration, high stability, premature release, low encapsulation rate and unspecific release kinetics. Thus, the aim of the present review is to outline a rapid and well-oriented scenario concerning the knowledge about polymer-hybrid nanoparticles use in biomedical platforms. Furthermore, the ultimate methodologies adopted in synthesis processes, as well as in applications in vitro/in vivo, are the focus of this review.

Targeted delivery of β-glucosidase-loaded magnetic nanoparticles: effect of external magnetic field duration and intensity

Aim: The effect of applied magnetic field duration and intensity on the delivery of β-glucosidase-loaded magnetic nanoparticles was evaluated. Materials & methods: The prepared β-glucosidase-loaded magnetic nanoparticles were targeted to subcutaneous tumors with an external magnetic field. Iron concentration and enzyme activity in tumor tissue were analyzed via electron spin resonance detection, Prussian blue staining and enzyme activity measurement. Results: The increase in magnetic nanoparticles quantity and enzyme activity in tumor tissue was not synchronous with the magnetic targeting duration. In addition, accumulation of magnetic nanoparticles and the increase in enzyme activity were not synchronous with the magnetic field intensity. Conclusion: The results suggested that appropriate magnetic field conditions should be considered for targeted delivery of bioactivity proteins based on magnetic nanoparticles.

Nanotechnology for angiogenesis: opportunities and challenges

Angiogenesis plays a critical role within the human body, from the early stages of life (i.e., embryonic development) to life-threatening diseases (e.g., cancer, heart attack, stroke, wound healing). Many pharmaceutical companies have expended huge efforts on both stimulation and inhibition of angiogenesis. During the last decade, the nanotechnology revolution has made a great impact in medicine, and regulatory approvals are starting to be achieved for nanomedicines to treat a wide range of diseases. Angiogenesis therapies involve the inhibition of angiogenesis in oncology and ophthalmology, and stimulation of angiogenesis in wound healing and tissue engineering. This review aims to summarize nanotechnology-based strategies that have been explored in the broad area of angiogenesis. Lipid-based, carbon-based and polymeric nanoparticles, and a wide range of inorganic and metallic nanoparticles are covered in detail. Theranostic and imaging approaches can be facilitated by nanoparticles. Many preparations have been reported to have a bimodal effect where they stimulate angiogenesis at low dose and inhibit it at higher doses.

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.

Polymers prepared through an “ATRP polymerization–esterification” strategy for dual temperature- and reduction-induced paclitaxel delivery

A dual temperature- and reduction-responsive nanovehicle with 29.36% paclitaxel loading was fabricated using an “ATRP polymerization–esterification” method for tumor suppression.

Doxorubicin derivative loaded acetal-PEG-PCCL micelles for overcoming multidrug resistance in MCF-7/ADR cells

Objective: This study was aimed to develop DOX-TPP loaded acetal-PEG-PCCL micelles to improve the clinical efficacy of drug resistance tumor. Significance: Chemotherapy is one of the main treatments for breast cancer but is plagued by multidrug resistance (MDR). DOX-TPP-loaded micelles can enhance the specific concentration of drugs in the tumor and improve the efficacy and overcome MDR. Methods: In this study, DOX-TPP-loaded micelles based on acetal-PEG-PCCL were prepared and their physicochemical properties were characterized. The cellular uptake and ability to induce apoptosis of the micelles was confirmed by flow cytometry in MCF-7/ADR cells. In addition, cytotoxicity of the micelles was studied in MCF-7 cells and MCF-7/ADR cells. Confocal is used to study the subcellular distribution of DOX. Free DOX-TPP or DOX-TPP-loaded acetal-PEG-PCCL micelles were administered via intravenous injection in the tail vain for the biodistribution study in vivo. Results: The diameter of micelles was about 102.4 nm and their drug-loading efficiency is 61.8%. The structural characterization was confirmed by 1H NMR. The micelles exhibited better antitumor efficacy compared to free doxorubicin in MCF-7/ADR cells by MTT assay. The apoptotic rate and the cellular uptake of micelles were significantly higher than free DOX and DOX-TPP. Micelles can efficiently deliver mitochondria-targeting DOX-TPP to tumor cells. The result of bio-distribution showed that the micelles had stronger tumor infiltration ability than free drugs. Conclusions: In this study, mitochondriotropic DOX-TPP was conjugated to the nanocarrier acetal-PEG-PCCL via ionic interaction to form a polymer, which spontaneously formed spherical micelles. The cytotoxicity and cellular uptake of the micelles are superior to free DOX and exhibit mitochondrial targeting and passive tumor targeting, indicating that they have potential prospects.

Paclitaxel-encapsulated core–shell nanoparticle of cetyl alcohol for active targeted delivery through oral route

Aim: Paclitaxel (PTX) has no clinically available oral formulations. Cetyl alcohol is metabolized by alcohol dehydrogenase and aldehyde dehydrogenase that are overexpressed in cancer cells. So, PTX-encapsulated core–shell nanoparticle of cetyl alcohol (PaxSLN) could target the cancer cells through oral route. Materials & methods: PaxSLN was synthesized using microemulsion template. Efficiency of PaxSLN was evaluated by ALDEFLUOR™, multicellular tumor spheroid formation inhibition assays and CT26 colorectal carcinoma animal model. Pharmacokinetics and biodistribution studies were done in Sprague Dawley rats. Results: PTX was encapsulated at the core of approximately 78 nm PaxSLN. PaxSLN targeted aldehyde dehydrogenase overexpressing cells. Its oral bioavailability was approximately 95% and chemotherapeutic efficacy was better than Taxol® and nab-PTX. Conclusion: A novel oral nanoformulation of PTX was developed.

Multifunctional Albumin-Stabilized Gold Nanoclusters for the Reduction of Cancer Stem Cells

Controlled delivery of multiple chemotherapeutics can improve the effectiveness of treatments and reduce side effects and relapses. Here in, we used albumin-stabilized gold nanoclusters modified with doxorubicin and SN38 (AuNCs-DS) as combined therapy for cancer. The chemotherapeutics are conjugated to the nanostructures using linkers that release them when exposed to different internal stimuli (Glutathione and pH). This system has shown potent antitumor activity against breast and pancreatic cancer cells. Our studies indicate that the antineoplastic activity observed may be related to the reinforced DNA damage generated by the combination of the drugs. Moreover, this system presented antineoplastic activity against mammospheres, a culturing model for cancer stem cells, leading to an efficient reduction of the number of oncospheres and their size. In summary, the nanostructures reported here are promising carriers for combination therapy against cancer and particularly to cancer stem cells.

Solidified SNEDDS for the oral delivery of rifampicin: Evaluation, proof of concept, in vivo kinetics, and in silico GastroPlusTM simulation

The present investigation was performed to develop a rifampicin (RIF)-loaded solidified self-nanoemulsifying drug delivery system (SNEDDS) (solidified RIF-OF1) for in vitro and in vivo evaluations. Optimized formulations were tested for their powder flow characteristics, loading efficiency, and in vitro dissolution (at pH-1.2, 6.8 and 7.4). Compatibility studies were also performed. The formulations were also tested for hemocompatibility, intestinal permeation, histopathological effects, and in vivo pharmacokinetics. Additionally, an in silico simulation study using GastroPlus was performed. At different varied pH values, we observed immediate release (T_85% within 15 min) based on the dissolution profile. This could be due to labrasol-assisted RIF solubilization. In vitro hemolysis study of the reconstituted RIF-OF1 revealed normal architecture of erythrocytes compared to the positive control (lysed and fragmented). Through in vivo permeation and biopsy studies, a rationale for facilitated intestinal permeation of RIF with components deemed physiological safe (normal anatomy of mucosal membrane evidenced from biopsy study) could be established. The in vitro-in vivo correlation (IVIVC) plus module of GastroPlus^TM simulation showed a good IVIVC between in vitro release and in vivo absorption with a predicted systemic absorption of ∼96.5%. Solidified SNEDDS showed improved pharmacokinetic profiles compared to RIF suspension. Solid RIF-SNEDDS was demonstrated to be a suitable carrier for enhanced intestinal permeation and oral bioavailability. Hence, it may serve as a suitable alternative to conventional delivery systems for tuberculosis treatment.

Melanoma tumour vasculature heterogeneity: from mice models to human

Tumour angiogenesis is defined by an anarchic vasculature and irregularities in alignment of endothelial cells. These structural abnormalities could explain the variability in distribution of nanomedicines in various tumour models. Then, the main goal of this study was to compare and to characterize the tumour vascular structure in different mouse models of melanoma tumours (B16F10 and SK-Mel-28) and in human melanomas from different patients. Tumours were obtained by subcutaneous injection of 10⁶ B16F10 and 3.10⁶ SK-Mel-28 melanoma cells in C57BL/6 and nude mice, respectively. Tumour growth was evaluated weekly, while vasculature was analysed through fluorescent labelling via CD31 and desmin. Significant differences in tumour growth and mice survival were evidenced between the two melanoma models. A fast evolution of tumours was observed for B16F10 melanoma, reaching a tumour size of 100 mm³ in 7 days compared to SK-Mel-28 which needed 21 days to reach the same volumes. Important differences in vascularization were exposed between the melanoma models, characterized by a significant enhancement of vascular density and a significant lumen size for mice melanoma models compared to human. Immunostaining revealed irregularities in endothelium structure for both melanoma models, but structural differences of vasculature were observed, characterized by a stronger expression of desmin in SK-Mel-28 tumours. While human melanoma mainly develops capillaries, structural irregularities are also observed on the samples of this tumour model. Our study revealed an impact of cell type and tumour progression on the structural vasculature of melanoma, which could impact the distribution of drugs in the tumour environment.

Sialic Acid-Functionalized pH-Triggered Micelles for Enhanced Tumor Tissue Accumulation and Active Cellular Internalization of Orthotopic Hepatocarcinoma

Both targeted and stimuli-sensitive drug-delivery systems (DDSs) have been developed to augment antitumor effects. However, lack of knowledge regarding tumor tissue targeting and different effects of the stimuli-sensitive DDSs in orthotropic and ectopic tumors have impeded further advances in their clinical applications. Herein, we first reported a pH-triggered micelle with sialic acid (SA)-driven targeting ability (SA-poly(ethylene glycol)-hydrazone linker-doxorubicin (DOX), SPD). The SPD micelles encapsulated with DOX (SPDD) showed sustained drug release over 48 h in response to the pH gradient in vivo, slow under physical conditions and accelerated in the acid tumor microenvironment. In addition, the SPD micelles showed 2.3-fold higher accumulation in tumors after 48 h compared to the micelles lacking the SA moiety. The overexpression of E-selectin on the inflammatory vascular endothelial cells surrounding the tumors increased the accumulation of SPD micelles in tumor tissues, whereas that on the tumor cells increased the internalization of micelles. Consequently, SPDD micelles exerted remarkable antitumor effects in both orthotopic and ectopic models. Application of SPDD micelles in the in situ model reduced the tumor volume (77.57 mm³ vs 62.13 mm³) and metastasis after treatment for 25 days. These results suggest that SA-driven targeted DDS with a pH-responsive switch has the potential to treat hepatocarcinoma effectively both ectopically and orthotopically.

Reassessment of long circulation via monitoring of integral polymeric nanoparticles justifies a more accurate understanding

Monitoring of payloads results in a biased perception of long circulation of nanoparticles. Instead, herein, the long-circulation effect was re-confirmed by monitoring integral nanoparticles, but circulation was not found to be as long as generally perceived. In contrast, disparate pharmacokinetics were obtained by monitoring a model drug, paclitaxel, highlighting the bias of the conventional protocol.

Polymeric Micelles Based on Modified Glycol Chitosan for Paclitaxel Delivery: Preparation, Characterization and Evaluation

Amphiphilic polymer of α-tocopherol succinate modified glycol chitosan (TS-GC) was successfully constructed by conjugating α-tocopherol succinate to the skeleton of glycol chitosan and characterized by Fourier-transform infrared (FT-IR) and proton nuclear magnetic resonance (¹H-NMR). In aqueous milieu, the conjugates self-assembled to micelles with the critical aggregation concentration of 7.2 × 10⁻³ mg/mL. Transmission electron microscope (TEM) observation and dynamic light scattering (DLS) measurements were carried out to determine the physicochemical properties of the micelles. The results revealed that paclitaxel (PTX)-loaded TS-GC micelles were spherical in shape. Moreover, the PTX-loaded micelles showed increased particle sizes (35 nm vs. 142 nm) and a little reduced zeta potential (+19 mV vs. +16 mV) compared with blank micelles. The X-ray diffraction (XRD) spectra demonstrated that PTX existed inside the micelles in amorphous or molecular state. In vitro and in vivo tests showed that the PTX-loaded TS-GC micelles had advantages over the Cremophor EL-based formulation in terms of low toxicity level and increased dose, which suggested the potential of the polymer as carriers for PTX to improve their delivery properties.

Redox-responsive micelles from disulfide bond-bridged hyaluronic acid-tocopherol succinate for the treatment of melanoma

Nanotechnology-based chemotherapy is efficient in cancer treatment due to the targeted delivery of small molecules via nano-carriers, which are usually regarded as "inert". However, nano-materials are more preferred as carriers since many cause synergistic anti-tumor effects along with the drug cargo. In this study, a "bioactive" tocopherol succinate (TOS) was grafted to hyaluronic acid (HA) via of disulfide bonds to obtain HA-ss-TOS conjugates which can assemble into nano-micelles but dissociate when exposed to reducing environments in vitro and in vivo. Moreover, paclitaxel-loaded HA-ss-TOS micelles (HA-ss-TOS-PTX) can be efficiently taken up by B16F10 cells overexpressing CD 44, thereafter exhibiting enhanced cytotoxicity. The in vivo imaging study here revealed much greater tumor accumulation of Dir-labeled HA-ss-TOS compared to the free Dir group. In vivo antitumor activities further ensured that the PTX-loaded HA-ss-TOS micelles provided superior antineoplastic responses versus PTX-loaded HA-TOS micelles and Taxol. Moreover, the subcellular dissociated TOS from HA-ss-TOS showed synergistic effects with PTX. These experimental results revealed that reduction-responsive PTX-loaded polymeric nano-micelles with multi-functional properties hold great potential for anti-tumor treatment and, thus, should be further studied.

Bridging the Knowledge of Different Worlds to Understand the Big Picture of Cancer Nanomedicines

Explosive growth of nanomedicines continues to significantly impact the therapeutic strategies for effective cancer treatment. Despite the significant progress in the development of advanced nanomedicines, successful clinical translation remains challenging. As cancer nanomedicine is a multidisciplinary field, the fundamental problem is that the knowledge gaps stem from different vantage points in the understanding of cancer nanomedicines. The complexities and heterogenecity of both nanomedicines and cancer are further demanding the integration of highly diverse expertise to develop clinically translatable cancer nanomedicines. This progress report aims to discuss the current understanding of cancer nanomedicines between different research areas in terms of nanoparticle engineering, formulation, tumor patho-physiology and clinical medicine, as well as to identify the knowledge gaps lying at the interface between the different fields of research in nanomedicine. Here we also highlight for the necessity to harmonize the multidisciplinary effort in the research of nanomedicines in order to bridge the knowledge and to advance the full understanding in cancer nanomedicines. A paradigm shift is needed in the strategic development of disease specific nanomedicines in order to foster the successful translation into clinic of future cancer nanomedicines.

Overcoming obstacles in the tumor microenvironment: Recent advancements in nanoparticle delivery for cancer theranostics

Despite rapid advancements in the field of nanotechnology, there is mounting frustration in the scientific community regarding the translational impact of nanomedicine. Modest therapeutic performance of FDA-approved nanomedicines combined with multiple disappointing clinical trials (such as phase III HEAT trial) have raised questions about the future of nanomedicine. Encouraging breakthroughs, however, have been made in the last few years towards the development of new classes of nanoparticles that can respond to tumor microenvironmental conditions and successfully deliver therapeutic agents to cancer cells. Concurrently, a great deal of effort has also been devoted to alter various parameters of tumor pathophysiology to pre-treat tumors before nanoparticles are administered. Such 'priming' treatments improve access of the systemically administered agents to the tumor and promote drug penetration into the deeper layers of tumor tissue. This review will highlight recent advances in cancer nanomedicine exploiting both nanoparticle design and tumor microenvironment modification; and provide a critical perspective on the future development of nanomedicine delivery in oncology.

Radionuclide I-131 Labeled Albumin-Paclitaxel Nanoparticles for Synergistic Combined Chemo-radioisotope Therapy of Cancer

Development of biocompatible/biodegradable materials with multiple functionalities via simple methods for cancer combination therapy has attracted great attention in recent years. Herein, paclitaxel (PTX), a popular anti-tumor chemotherapeutic drug, is used to induce the self-assembly of human serum albumin (HSA) pre-labeled with radionuclide I-131, obtaining 131I-HSA-PTX nanoparticles for combined chemotherapy and radioisotope therapy (RIT) of cancer. Such 131I-HSA-PTX nanoparticles show prolonged blood circulation time, high tumor specific uptake and excellent intra-tumor penetration ability. Interestingly, as revealed by in vivo photoacoustic imaging and ex vivo immunofluorescence staining, PTX delivered into the tumor by HSA-nanoparticle transportation can remarkably enhance the tumor local oxygen level and suppress the expression of HIF-1α, leading to greatly relieved tumor hypoxia. As the results, the combined in vivo chemotherapy & RIT with 131I-HSA-PTX nanoparticles in the animal tumor model offers excellent synergistic therapeutic efficacy, likely owing to the greatly modulated tumor microenvironment associated with PTX-based chemotherapy. Therefore, in this work, a simple yet effective therapeutic agent is developed for synergistic chemo-RIT of cancer, promising for future clinic translations in cancer treatment.

Juglone loaded poloxamer 188/phospholipid mixed micelles evaluated in vitro and in vivo in breast cancer

AIM

Investigating the effects of juglone loaded P188/phospholipid mixed micelles (J-MM) in breast cancer.

MATERIALS & METHODS

In vitro cytotoxicity, apoptotic effects, in vivo therapeutic efficacy and toxicity were used to assess its antitumour effect. Uptake and imaging were used to evaluate the effect on the uptake and passive targeting.

RESULTS

Mixed micelle carrier enhanced the targeting and uptake by MB-231 cells. The tumour inhibition rates in tumour xenograft models for paclitaxel, juglone, J-MM (10mg/kg) and J-MM (40mg/kg) were 46%, 27%, 39% and 53%, respectively. J-MM (10mg/kg) exhibited lower toxicity compared with that by free juglone or high dose J-MM.

CONCLUSION

J-MM exhibited low toxicity, improved cellular uptake, passive targeting and anti-cancer effects in breast cancer model.

Imaging-guided photoacoustic drug release and synergistic chemo-photoacoustic therapy with paclitaxel-containing nanoparticles

Here, a novel triggered drug release modality was developed for oncotherapy. Paclitaxel (PTX), perfluorohexane (PFH) and gold nanorods (AuNRs) loaded nanoparticles (PTX-PAnP) were synthesized. Folic acid (FA) conjugated PTX-PAnP (PTX-PAnP-FA) could be selectively taken into folate receptor-overexpressed tumor cells. Upon pulsed laser irradiation, the PTX-PAnP-FA could be rapidly destructed because of the PFH vaporization, resulting in fast drug release, which induced apoptosis of cancer cells efficiently. Stimulated fragmentation of the PTX-PAnP-FA nanoparticles can facilitate multiple mechanisms such as bubble implosion, shockwave generation, and sonoporation that further enhance the therapeutic efficiency. The in vivo therapy study further confirmed this new approach resulted in efficient tumor suppression. The results demonstrate a unique drug release mechanism based on photoacoustic effect. It provides an all-in-one platform for photoacoustic image-guided drug release and synergistic chemo-photoacoustic therapy.

A dual strategy to improve the penetration and treatment of breast cancer by combining shrinking nanoparticles with collagen depletion by losartan

Although development of nanomedicines has been a promising direction in tumor treatment, the therapeutic outcome of current nanomedicines is unsatisfying, partly because of the poor retention and penetration in tumors. Recently, a kind of tumor microenvironment sensitive size shrinkable nanoparticles (DOX-AuNPs-GNPs) has been developed by our lab, which could enhance the tumor penetration and retention depending on the size shrinking. However, the further enhancement is still restricted by dense collagen network in tumors. Thus in this study, we combined DOX-AuNPs-GNPs with losartan to deplete tumor collagen (constituted up to 90% of extracellular matrix) to further improve tumor penetration. In vitro, DOX-AuNPs-GNPs can shrink from over 117.8nm to less than 50.0nm and release DOX-AuNPs under the triggering of tumor overexpressed matrix metalloproteinases-2 (MMP-2). In vivo, pretreatment with losartan significantly decrease the collagen level and improve the tumor penetration. In combination, losartan combined with DOX-AuNPs-GNPs showed the best drug delivery efficiency, striking penetration efficiency and best 4T1 breast tumor inhibition effect. In conclusion, this study provided a promising synergetic strategy to improve the tumor treatment efficiency of nanomedicines.

STATEMENT OF SIGNIFICANCE

We have developed a dual strategy for deep tumor penetration through combining size shrinkable DOX-AuNPs-GNPs with depleting tumor collagen by losartan. Additionally, we demonstrate therapeutic efficacy in breast tumor bearing mouse model. DOX-AuNPs-GNPs co-administration with losartan is a novel and highly attractive strategy for anti-tumor drug delivery with the potential for broad applications in clinic.

Effect of paclitaxel-loaded nanoparticles on the viability of human hepatocellular carcinoma HepG2 cells

OBJECTIVE

To explore effects of paclitaxel-loaded poly lactic-co-glycolic acid (PLGA) particles on the viability of human hepatocellular carcinoma (HCC) HepG2 cells.

MATERIALS AND METHODS

The viability of HepG2 cells was assessed using MTT under different concentrations of prepared paclitaxel-loaded particles and paclitaxel (6.25, 12.5, 25, 50, and 100 mg/L), and apoptosis was analyzed using Hochest33342/Annexin V-FITC/PI combined with an IN Cell Analyzer 2000.

RESULTS

Paxlitaxel-loaded nanoparticles were characterized by narrow particle size distribution (158.6 nm average particle size). The survival rate of HepG2 cells exposed to paclitaxel-loaded PLGA particles decreased with the increase of concentration and time period (P<0.01 or P<0.05), the dose- and time-dependence indicating sustained release (P<0.05). Moreover, apoptosis of HepG2 cells was induced, again with an obvious dose- and time-effect relationship (P<0.05).

CONCLUSIONS

Paclitaxel-loaded PLGA particles can inhibit the proliferation and induce the apoptosis of HCC HepG2 cells. This new-type of paclitaxel carrier body is easily made and has low cost, good nanoparticle characterization and sustained release. Hence, paclitaxel- loaded PLGA particles deserve to be widely popularized in the clinic.

In vivo pharmacokinetics, biodistribution and antitumor effect of paclitaxel-loaded micelles based on α-tocopherol succinate-modified chitosan

In our previous study, α-tocopherol succinate modified chitosan (CS-TOS) was synthesized and encapsulated paclitaxel (PTX) to form micelles. Preliminary study revealed that the CS-TOS was a potential micellar carrier for PTX. In this study, some further researches were done using Taxol formulation as the control to evaluate the micelle system deeply. In vitro cell experiments demonstrated that the cytotoxic effect of PTX-loaded CS-TOS micelles against MCF-7 cells was comparable with that of Taxol formulation, and the PTX-loaded micelles had excellent cellular uptake ability, which was in a time-dependent manner. The in vivo pharmacokinetic study in rats showed that the micelles prolonged the half-life and increased AUC of PTX than Taxol formulation. From biodistribution study, it was clear that for micelles, the drug concentrations in the liver and spleen were significantly higher than those of Taxol formulation, but much lower in the heart and kidney. Furthermore, the PTX-loaded micelles showed superior antitumor effect, but yielded less toxicity as indicated by the results of antitumor efficacy study and survival study in U14 tumor-bearing mice. These results suggested that CS-TOS micelles could be a potentially useful drug delivery system to improve the performance and safety of PTX.

Redox-sensitive hyaluronic acid–paclitaxel conjugate micelles with high physical drug loading for efficient tumor therapy

Characterization of targeted redox-sensitive micelles self-assembled from polymer–drug conjugates exhibiting conspicuous drug loading capabilities, selective cellular uptake, rapid intracellular disassembly and drug release is presented.