Co-delivery of dimeric camptothecin and chlorin e6 via polypeptide-based micelles for chemo-photodynamic synergistic therapy.

BACKGROUND: The integration of photodynamic therapy with a chemical drug-delivery system has displayed great potential in enhancing anticancer therapy. However, the solubility and non-specific biodistribution of both chemotherapeutic agents and photosensitizers continue to pose challenges that hinder their clinical applications. METHOD: A polypeptide-based nanoscale drug delivery system was fabricated to address the prementioned issues. An amphiphilic polymer was formed by conjugating the photosensitizer chlorin e6 (Ce6) onto a polypeptide poly-(L-lysine)-b-polyphenylalanine (PKF) for encapsulating the model drug dimeric camptothecin (DCPT), and the nanoparticles (PCD) with high drug loading efficiency were further modified with acid-sensitive polyethylene glycol (PEG) to yield the drug delivery sytem (PPCD). RESULTS: The DCPT and Ce6 encapsulation efficiency were analyzed as 99% and 73.5%, respectively. In phosphate-buffered saline (PBS) solution at a pH of 7.4, the PEG shell improved the stability of micelles and shielded their positive charge while in the acidic tumor microenvironment, the pH-sensitive PEG layer was removed to expose the cationic nanoparticles, thus facilitating the cellular uptake of PPCD micelles. Benefiting from the enhanced cellular internalization, the amount of intracellular reactive oxygen species (ROS) treated with PCD and PPCD micelles were obviously increased. Furthermore, the enhanced anti-cancer efficacy prompted by PPCD micelles was validated through cellular and animal study. CONCLUSION: This study presents a promising method to promote the solubility and biodistribution of both chemotherapeutic agent and photosensitizer, thereby facilitating the further application of chemo-photodynamic cancer therapy.

Biotransformation of triterpenoid ganoderic acids from exogenous diterpene dihydrotanshinone I in the cultures of Ganoderma sessile.

BACKGROUND: Triterpenoids have shown a wide range of biological activities including antitumor and antiviral effects. Typically, triterpenes are synthesized through the mevalonate pathway and are extracted from natural plants and fungi. In this work, triterpenoids, ganoderic acids (GAs) were discovered to be produced via biotransformation of a diterpene, 15,16-dihydrotanshinone I (DHT) in the liquid cultured Ganoderma sessile mycelium. RESULTS: Firstly, the biotransformation products, two rare GAs were isolated and purified by column chromatography, and characterized using HR-ESI-MS spectrometry and NMR spectrometry. The two compounds were Lanosta-7,9(11),24-trien-15α,22,ß-diacetoxy-3ß-hydroxy-26-oic acid (LTHA) and Lanosta-7,9(11),24-trien-15α,22,ß-diacetoxy-3ß-carbonyl-26-oic acid (LTCA). Then, transcriptome and proteome technologies were employed to measure the expression of mRNA and protein, which further confirmed that triterpenoid GAs could be transformed from exogenous diterpenoid DHT. At the molecular level, we proposed a hypothesis of the mechanism by which DHT converted to GAs in G. sessile mycelium, and the possible genes involved in biotransformation were verified by RT-qPCR. CONCLUSIONS: Two rare GAs were obtained and characterized. A biosynthetic pathway of GAs from DHT was proposed. Although the synthetic route was not confirmed, this study provided important insights into omics resources and candidate genes for studying the biotransformation of diterpenes into triterpenes.

Linear-like polypeptide-based micelle with pH-sensitive detachable PEG to deliver dimeric camptothecin for cancer therapy.

Nano drug delivery systems have made significant progress in delivering anticancer drugs camptothecin (CPT). However, many challenges for CPT delivery remain, including low drug loading efficiency, premature drug leakage, and poor cellular internalization. Herein, we report a novel dual-sensitive polypeptide-based micelle with remarkably high drug loading of CPT for cancer therapy. This self-assembled micelle possesses the following essential components for CPT: (1) pH-sensitive PEG (OHC-PEG-CHO) for prolonging blood circulation and allowing biocompatibility by shielding the cationic micelles, which can be detached under the tumor acidic microenvironment and facilitates the cellular uptake; (2) polypeptide polylysine-polyphenylalanine (PKF) synthesized via ring-opening polymerization for micelle formation and CPT analogue loading; (3) dimeric CPT (DCPT) with redox-sensitive linker for increasing CPT loading and ensuring drug release at tumor sites. Interestingly, the linear-like morphology of PEG-PKF/DCPT micelles was able to enhance their cellular internalization when compared with the spherical blank PKF micelles. Also, the anticancer efficacy of DCPT against lung cancer cells was significantly improved by the micelle formation. In conclusion, this work provides a promising strategy facilitating the safety and effective application of CPT in cancer therapy.

Functionalized PAMAM constructed nanosystems for biomacromolecule delivery.

Polyamidoamines (PAMAMs) are a class of dendrimer with monodispersity and controlled topology, which can deliver biologically active macromolecules (e.g., genes and proteins) to specific regions with high efficiency and minimum side effects. In detail, PAMAMs can be functionalized easily by core modification or surface amendment to encapsulate a wide range of biomacromolecules. Besides, self-assembled, cross-linked and hybrid PAMAMs with customized therapeutic purposes are developed as delivery vehicles, which makes PAMAMs promising for biomacromolecule therapy. In this review, we comprehensively summarize the application of PAMAMs in biomacromolecule delivery from the synthesis of functionalized PAMAM carriers to the development of PAMAM-based drug delivery systems. The underlying strategies for PAMAM functionalization and assembly are first systematically discussed, and then the current applications of PAMAMs for biomacromolecule delivery are reviewed. Finally, a brief perspective on the further applications of PAMAMs concludes, aiming to provide insights into developing PAMAM-based biomacromolecule delivery systems.

Development of nanoscale drug delivery systems of dihydroartemisinin for cancer therapy: A review.

Dihydroartemisinin (DHA), a first-line antimalarial drug, has demonstrated great anticancer effects in many types of tumors, including liver cancer, glioblastoma, and pancreatic cancer. Due to its abilities to induce programmed cell death (PCD; apoptosis, autophagy and ferroptosis), inhibit tumor metastasis and angiogenesis, and modulate the tumor microenvironment, DHA could become an antineoplastic agent in the foreseeable future. However, the therapeutic efficacy of DHA is compromised owing to its inherent disadvantages, including poor stability, low aqueous solubility, and short plasma half-life. To overcome these drawbacks, nanoscale drug delivery systems (NDDSs), such as polymeric nanoparticles (NPs), liposomes, and metal-organic frameworks (MOFs), have been introduced to maximize the therapeutic efficacy of DHA in either single-drug or multidrug therapy. Based on the beneficial properties of NDDSs, including enhanced stability and solubility of the drug, prolonged circulation time and selective accumulation in tumors, the outcomes of DHA-loaded NDDSs for cancer therapy are significantly improved compared to those of free DHA. This review first summarizes the current understanding of the anticancer mechanisms of DHA and then provides an overview of DHA-including nanomedicines, aiming to provide inspiration for further application of DHA as an anticancer drug.

Review of Current Strategies for Delivering Alzheimer's Disease Drugs Across the Blood-Brain Barrier.

(Appeared originally in the International Journal of Molecular Sciences 2019; 20:381) Reprinted under Creative Commons CC-BY license.

NIR-responsive polydopamine-based calcium carbonate hybrid nanoparticles delivering artesunate for cancer chemo-photothermal therapy.

Artesunate (AS), the first-line treatment of malaria with a satisfactory safety profile, has been repurposed as a potential anticancer candidate as it mainly generates reactive oxygen species (ROS) through its intrinsic endoperoxide bridge reacting with ferrous-based catalysts to suppress cancer cell growth. However, further clinical translation of AS is hindered by the attenuated anticancer efficacy due to insufficient ROS generation. Herein, we rationally integrated hydrophobic-modified AS (hAS) with biomimetic polydopamine (PDA) and biomineral calcium carbonate to fabricate high AS-loaded nanomedicine (Ca-PDA/hAS@PEG) for cancer chemo-photothermal therapy, which exerted anticancer effects in the following ways: (1) the heat was generated when PDA was irradiated by near-infrared (NIR) light for photothermal therapy. Meanwhile, the increased temperature accelerated the production of ROS from hAS, thus enhancing the anticancer efficacy of hAS-based chemotherapy; (2) hAS-mediated chemotherapy boosted the cancer inhibition effect of photothermal therapy by arousing the intracellular ROS levels in the presence of endogenous ferrous ions and sensitizing cancer cells to thermal ablation; (3) the integration of calcium carbonate into the nanoparticle facilitated the pH-responsive drug release for precise treatment. Such hybrid nanoparticles exhibited a combinational antitumor effect of photothermal therapy and chemotherapy in vivo with no systemic toxicity. Taken together, our work presents a facile strategy to improve the anticancer efficacy of AS by combining chemical modification and photothermal therapy-assisted endoperoxide bridge cleavage, which may offer opportunities to pave the way for clinical translation of AS-based nanomedicines. STATEMENT OF SIGNIFICANCE: The clinical translation of artesunate (AS) is hindered by the attenuated anticancer efficacy due to insufficient ROS generation. Herein, we rationally integrated hydrophobic-modified AS (hAS) with biomimetic polydopamine (PDA) and biomineral calcium carbonate to fabricate high AS-loaded nanomedicine (Ca-PDA/hAS@PEG) for improved cancer chemo-photothermal therapy. The heat generated from PDA in response to near-infrared light irradiation could locally ablate tumor as well as accelerate the production of ROS by hAS, thus enhancing the anticancer efficacy of hAS-based chemotherapy. On the other hand, hAS-based chemotherapy amplified the intracellular oxidative stress, sensitizing cancer cells to thermal ablation. Our work presents a facile strategy to improve the anticancer efficacy of AS by combining chemical modification and photothermal therapy-assisted endoperoxide bridge cleavage.

ROS-responsive dexamethasone micelles normalize the tumor microenvironment enhancing hypericin in cancer photodynamic therapy.

The efficacy of photodynamic therapy (PDT) for cancer is limited owing to the abnormality of the tumor microenvironment (TME), such as the dysfunctional tumor vascular system leading to restricted drug distribution in tumor lesions, and hypoxia resulting in hampering the application of the photosensitizer because of the shortage of oxygen. Therefore, normalizing the TME is a novel strategy for enhancing the therapeutic efficacy of PDT. Herein, we designed and fabricated reactive oxygen species (ROS)-responsive micelles with a self-circulating release manner to co-deliver a glucocorticoid steroid dexamethasone (DXM) and a photosensitizer hypericin (HYP) (denoted as HDTM). The current drug delivery system showed the following advantageous properties: (1) The DXM inhibited the migration, invasion and angiogenesis of vein endothelial cells by suppressing the function of vascular endothelial growth factor, thus promoting the delivery of oxygen and HDTM into the tumor site. (2) When the HDTM arrived at the tumor site, the endogenous ROS partially cleaved the outer shell of the micelle to release the HYP and DXM. With the use of an external light source with a wavelength of 590 nm, the in situ released HYP was excited, enabling ROS production, which resulted in effective cell apoptosis. Moreover, the upregulated ROS further cleaved the micelles, thus achieving the subsequent self-circulating burst release of HYP and DXM for PDT. Notably, real-time accumulation and elimination of drugs can be monitored owing to the red fluorescence property of HYP. This facile design not only provides a platform for cancer theranostics, but also offers a feasible strategy to combat cancer in an integral way.

ROS-responsive fluorinated polyethyleneimine vector to co-deliver shMTHFD2 and shGPX4 plasmids induces ferroptosis and apoptosis for cancer therapy.

Ferroptosis is a newly discovered non-apoptotic cell death form but its therapeutic efficacy triggered by traditional iron-based nanomaterials or classic drug inducers has been far from satisfactory due to the high glutathione (GSH) level in cancer cells and insufficient lipid peroxide production. Here we reported a ferroptosis/apoptosis combinational therapy by depleting GSH and downregulating GPX4 to disrupt redox homeostasis and amplify ferroptosis-related oxidation effect. In this study, we developed reactive oxygen species (ROS)-responsive serum-resistant nanoparticles with thioketal-crosslinked fluorinated polyethyleneimine 1.8K (TKPF) as the core, which were wrapped with hyaluronic acid (HA) as the shell (TKPFH NP) to co-deliver shGPX4 and shMTHFD2 plasmids for cancer treatment. The highly efficient and tumor-selective gene carrier TKPFH NPs revealed outstanding transfection efficiency (∼100 %) and sustained the efficiency (∼50 %) even in media containing 90 % FBS. Mediated by HA, TKPFH NPs actively targeted CD44 receptors, thus enabling efficient uptake by tumor cells and experiencing surface charge conversion to induce subsequent lysosomal escape. Then the TKPF NPs were effectively disintegrated by the abundant ROS in cancer cells, which facilitated the release of plasmids and avoided the cytotoxicity of cationic polymers. shGPX4 plasmid induced ferroptosis by producing ROS and lipid peroxides via downregulating GPX4, while shMTHFD2 triggered apoptosis by modulating NADPH/NADP and depleting GSH of the cancer cells. Moreover, GSH consumption caused by shMTHFD2 indirectly suppressed GPX4 and further augmented ferroptosis, showing synergistic anticancer effect against B16-F10 cells. Taken together, the rationally designed dual-gene loaded TKPFH NPs provided a safe and high-performance platform for enhanced ferroptosis-apoptosis combined anticancer efficacy based on gene therapy. STATEMENT OF SIGNIFICANCE: The therapeutic efficacy of ferroptosis has been far from satisfactory due to high GSH level and insufficient lipid peroxide production in cancer cells. Herein, we reported a ferroptosis/apoptosis combinational therapy by depleting GSH and downregulating GPX4 to disrupt redox homeostasis and amplify ferroptosis-related oxidation effect. ROS-responsive serum-resistant nanoparticles were fabricated with thioketal-crosslinked fluorinated PEI 1.8K (TKPF) as the core and hyaluronic acid (HA) as the shell (TKPFH NP) to co-deliver shGPX4 and shMTHFD2 plasmids. The shGPX4 plasmid induced ferroptosis by producing ROS and lipid peroxides via downregulating GPX4, while shMTHFD2 triggered apoptosis by modulating NADPH/NADP and depleting GSH. The rationally designed dual-gene loaded TKPFH NPs provided a safe and high-performance platform aimed for enhanced ferroptosis-apoptosis combined anticancer efficacy.

Natural Ingredient-Based Polymeric Nanoparticles for Cancer Treatment.

Cancer is a global health challenge. There are drawbacks to conventional chemotherapy such as poor bioavailability, development of drug resistance and severe side effects. Novel drug delivery system may be an alternative to optimize therapeutic effects. When such systems consist of natural materials, they offer important advantages: they are usually highly biocompatible, biodegradable, nontoxic and nonimmunogenic. Furthermore, natural materials can be easily modified for conjugation with a wide range of therapeutic agents and targeting ligands, according to the therapeutic purpose. This article reviews different natural ingredients and their applications in drug delivery systems for cancer therapy. Firstly, an overview of the polysaccharides and protein-based polymers that have been extensively investigated for drug delivery are described. Secondly, recent advances in using various natural ingredient-based polymeric nanoparticles for cancer therapy are reviewed. The characteristics of these delivery systems are summarized, followed by a discussion of future development and clinical potential. This review aims to summarize current knowledge and provide a basis for developing effective tailor-made formulations for cancer therapy in the future.

Delivering Crocetin across the Blood-Brain Barrier by Using γ-Cyclodextrin to Treat Alzheimer's Disease.

Crocetin (CRT) has shown various neuroprotective effects such as antioxidant activities and the inhibition of amyloid ß fibril formation, and thus is a potential therapeutic candidate for Alzheimer's disease (AD). However, poor water solubility and bioavailability are the major obstacles in formulation development and pharmaceutical applications of CRT. In this study, a novel water-soluble CRT-γ-cyclodextrin inclusion complex suitable for intravenous injection was developed. The inclusion complex was nontoxic to normal neuroblastoma cells (N2a cells and SH-SY5Y cells) and AD model cells (7PA2 cells). Furthermore, it showed stronger ability to downregulate the expression of C-terminus fragments and level of amyloid ß in 7PA2 cell line as compared to the CRT free drug. Both inclusion complex and CRT were able to prevent SH-SY5Y cell death from H2O2-induced toxicity. The pharmacokinetics and biodistribution studies showed that CRT-γ-cyclodextrin inclusion complex significantly increased the bioavailability of CRT and facilitated CRT crossing the blood-brain barrier to enter the brain. This data shows a water-soluble γ-cyclodextrin inclusion complex helped to deliver CRT across the blood-brain barrier. This success should fuel further pharmaceutical research on CRT in the treatment for AD, and it should engender research on γ-cyclodextrin with other drugs that have so far not been explored.

Targeting Approaches of Nanomedicines in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a hematological malignancy, which is commonly associated with high incidence and mortality among adult patients. The standard induction regimen for AML has been substantially unchanged over the past 40 years, for which novel nanomedicines have represented a promising strategy in AML therapies. Despite developments of multiple nanoparticles formulated with drugs or genes, less there is not much information available about approaches in AML is available. This review presents an overview of nanomedicines currently being evaluated in AML. First, it briefly summarized conventional chemotherapies in use. Second, nanomedicines presently ongoing in clinical trials or preclinical researches were classified and described, with illustrative examples from recent literatures. Finally, limitations and potential safety issues concerns in clinical translation of AML treatment were discussed as well.

Pulmonary delivery of transferrin receptors targeting peptide surface-functionalized liposomes augments the chemotherapeutic effect of quercetin in lung cancer therapy.

Purpose: Lung cancer has a high incidence rate worldwide with a 5-year survival rate of 18%, and is the leading cause of cancer-related deaths. The aim of this study is to augment therapeutic efficacy of quercetin (QR) for lung cancer therapy by targeting transferrin receptors, which are overexpressed and confined to tumor cells. Methods: In this study, T7 surface-functionalized liposomes loaded with QR (T7-QR-lip) having different T7 peptide densities (0.5%, 1% and 2%) were prepared by the film hydration method. T7 surface-functionalized liposomes were characterized and evaluated in terms of in vitro cytotoxicity and cellular uptake, 3D tumor spheroid penetration and inhibition capabilities, in vivo biodistribution and therapeutic efficacy in mice with orthotopic lung-tumor implantation by fluorescent and bioluminescent imaging via pulmonary administration. Results: In vitro, 2% T7-QR-lip exhibited significantly augmented cytotoxicity (~3-fold), higher apoptosis induction and S-phase cell-cycle arrest. A prominent peak right-shift and enhanced mean fluorescence intensity was observed in A549 cells treated with T7 Coumarin-6 liposomes (T7-Cou6-lip), confirming the target specificity of T7 targeted liposomes; while, after treatment with T7-QR-lip and non-targeted QR-lip, no significant difference was observed in cellular uptake and in vitro cytotoxicity studies in MRC-5 (normal lung fibroblast) cells. T7-Cou6-lip showed higher fluorescence intensity in A549 cells and a significantly deeper penetration depth of 120 µm in the core of the tumor spheroids and T7-QR-lip produced significantly higher tumor-spheroid growth inhibition. The in vivo biodistribution study via pulmonary delivery of T7 1,1'-dioctadecyltetramethyl-indotricarbocyanine iodide liposomes demonstrated liposome accumulation in the lungs and sustained-release behavior up to 96 h. Further, T7-QR-lip significantly enhanced the anticancer activity of QR and lifespan of mice (p<0.01, compared with saline) in orthotopic lung tumor-bearing mice via pulmonary administration. Conclusion: T7 surface-functionalized liposomes provide a potential drug delivery system for a range of anticancer drugs to enhance their therapeutic efficacy by localized (pulmonary) administration and targeted delivery.

Review of Current Strategies for Delivering Alzheimer's Disease Drugs across the Blood-Brain Barrier.

Effective therapy for Alzheimer's disease is a major challenge in the pharmaceutical sciences. There are six FDA approved drugs (e.g., donepezil, memantine) that show some effectiveness; however, they only relieve symptoms. Two factors hamper research. First, the cause of Alzheimer's disease is not fully understood. Second, the blood-brain barrier restricts drug efficacy. This review summarized current knowledge relevant to both of these factors. First, we reviewed the pathophysiology of Alzheimer's disease. Next, we reviewed the structural and biological properties of the blood-brain barrier. We then described the most promising drug delivery systems that have been developed in recent years; these include polymeric nanoparticles, liposomes, metallic nanoparticles and cyclodextrins. Overall, we aim to provide ideas and clues to design effective drug delivery systems for penetrating the blood-brain barrier to treat Alzheimer's disease.

Surface Functionalization and Targeting Strategies of Liposomes in Solid Tumor Therapy: A Review.

Surface functionalization of liposomes can play a key role in overcoming the current limitations of nanocarriers to treat solid tumors, i.e., biological barriers and physiological factors. The phospholipid vesicles (liposomes) containing anticancer agents produce fewer side effects than non-liposomal anticancer formulations, and can effectively target the solid tumors. This article reviews information about the strategies for targeting of liposomes to solid tumors along with the possible targets in cancer cells, i.e., extracellular and intracellular targets and targets in tumor microenvironment or vasculature. Targeting ligands for functionalization of liposomes with relevant surface engineering techniques have been described. Stimuli strategies for enhanced delivery of anticancer agents at requisite location using stimuli-responsive functionalized liposomes have been discussed. Recent approaches for enhanced delivery of anticancer agents at tumor site with relevant surface functionalization techniques have been reviewed. Finally, current challenges of functionalized liposomes and future perspective of smart functionalized liposomes have been discussed.