Beta-lapachone-containing PEG-PLA polymer micelles as novel nanotherapeutics against NQO1-overexpressing tumor cells

β-Lapachone, an NQO1 bioactivatable drug, prevents lung tumorigenesis in mice

Lung cancer is one of the most lethal cancers with high incidence worldwide. The prevention of lung cancer is of great significance to reducing the social harm caused by this disease. An in-depth understanding of the molecular changes underlying precancerous lesions is essential for the targeted chemoprevention against lung cancer. Here, we discovered an increased NQO1 level over time within pulmonary premalignant lesions in both the KrasG12D-driven and nicotine-derived nitrosamine ketone (NNK)-induced mouse models of lung cancer, as well as in KrasG12D-driven and NNK-induced malignant transformed human bronchial epithelial cells (BEAS-2B and 16HBE). This suggests a potential correlation between the NQO1 expression and lung carcinogenesis. Based on this finding, we utilized β-Lapachone (β-Lap), an NQO1 bioactivatable drug, to suppress lung tumorigenesis. In this study, the efficacy and safety of low-dose β-Lap were demonstrated in preventing lung tumorigenesis in vivo. In conclusion, our study suggests that long-term consumption of low-dose β-Lap could potentially be an effective therapeutic strategy for the prevention of lung premalignant lesions. However, further studies and clinical trials are necessary to validate our findings, determine the safety of long-term β-Lap usage in humans, and promote the use of β-Lap in high-risk populations.

A Novel Polyamino Acid Sulfur Dioxide Prodrug Synergistically Elevates ROS with β-Lapachone in Cancer Treatment

Due to the distorted redox balance, cancer cells are considered more vulnerable to excessive reactive oxygen species (ROS). In a variety of oxidative stress-related therapies, gas therapy has emerged as a new therapeutic strategy owing to its efficacy and biosafety. Herein, a newly-discovered gasotransmitter sulfur dioxide (SO2) and a tumor specific ROS generation agent β-lapachone (Lapa) were firstly combined for anticancer therapy. Firstly, amphiphilic glutathione (GSH) responsive polypeptide SO2 prodrug PEG-b-poly(Lys-DNs) was synthesized by ring opening polymerization of SO2-containing N-carboxyanhydride. Then, Lapa was encapsulated into the polymeric micelles with loading content of 8.6 % and loading efficiency of 51.6 %. The obtained drug-loaded nanoparticles (NPs(Lapa)) exhibited a fast release of Lapa and SO2 in the stimuli of 10 mM GSH in PBS. Subsequently, in vitro experiment showed that NPs(Lapa) exhibited obvious cytotoxicity towards 4 T1 cancer cells at a concentration of 2.0 μg/mL, which may be attributed to the depletion of intracellular GSH and upregulation of ROS level both by SO2 release and by the ROS generation from lapachone transformation. In vivo fluorescence imaging showed that the NPs were gradually enriched in tumor tissues in 24 h, probably due to the enhanced permeability and retention effect of NPs. Finally, NPs(Lapa) showed the best anticancer effect in 4 T1 tumor bearing mice with a tumor inhibiting rate (IRT) of 61 %, whereas IRT for free Lapa group was only 23.6 %. This work may be a new attempt to combine SO2 gas therapy with ROS inducer for anticancer therapy through oxidative stress.

Elucidation of Protonation Cooperativity of a STING-Activating Polymer

Stimuli-responsive nanomaterials have the potential to improve the performance and overcome existing barriers of conventional nanotherapeutics. Molecular cooperativity design in stimuli-responsive nanomedicine can amplify physiological signals, enabling a cooperative response for improved diagnostic and therapeutic precision. Previously, this work reported an ultra-pH-sensitive polymer, PEG-b-PC7A, that possesses innate immune activating properties by binding to the stimulator of interferon genes (STING) through polyvalent phase condensation. This interaction enhances STING activation and synergizes with the endogenous STING ligand for robust cancer immunotherapy. Despite its successes in innate immune activation, the fundamental physicochemical and pH-responsive properties of PC7A require further investigation. Here, this study elucidates the protonation cooperativity driven by the phase transition of PC7A copolymer. The highly cooperative system displays an "all-or-nothing" proton distribution between highly charged unimer (all) and neutral micelle (nothing) states without gradually protonated intermediates. The binary protonation behavior is further illustrated in pH-precision-controlled release of a representative anticancer drug, β-lapachone, by PC7A micelles over a noncooperative PE5A polymer. Furthermore, the bimodal distribution of protons is represented by a high Hill coefficient (nH  > 9), featuring strong positive cooperativity. This study highlights the nanoscale pH cooperativity of an immune activating polymer, providing insights into the physicochemical characterization and design parameters for future nanotherapeutics development.

Chemopreventive Potential of Dietary Nanonutraceuticals for Prostate Cancer: An Extensive Review

There are more than two hundred fifty different types of cancers, that are diagnosed around the world. Prostate cancer is one of the suspicious type of cancer spreading very fast around the world, it is reported that in 2018, 29430 patients died of prostate cancer in the United State of America (USA), and hence it is expected that one out of nine men diagnosed with this severe disease during their lives. Medical science has identified cancer at several stages and indicated genes mutations involved in the cancer cell progressions. Genetic implications have been studied extensively in cancer cell growth. So most efficacious drug for prostate cancer is highly required just like other severe diseases for men. So nutraceutical companies are playing major role to manage cancer disease by the recommendation of best natural products around the world, most of these natural products are isolated from plant and mushrooms because they contain several chemoprotective agents, which could reduce the chances of development of cancer and protect the cells for further progression. Some nutraceutical supplements might activate the cytotoxic chemotherapeutic effects by the mechanism of cell cycle arrest, cell differentiation procedures and changes in the redox states, but in other, it also elevate the levels of effectiveness of chemotherapeutic mechanism and in results, cancer cell becomes less reactive to chemotherapy. In this review, we have highlighted the prostate cancer and importance of nutraceuticals for the control and management of prostate cancer, and the significance of nutraceuticals to cancer patients during chemotherapy.

Enzymatic drug release cascade from polymeric prodrug nanoassemblies enables targeted chemotherapy

Cancer drug delivery systems often suffer from premature drug leakage during transportation and/or inefficient drug release within cancer cells. We present here a polymeric prodrug nanoassembly that addresses these problems simultaneously. This nanoassembly comprises a polymeric prodrug with novel trivalent phenylboronate moieties for drug conjugation via ether linkages, as well as β-lapachone (Lapa). While the ether linkage enables nearly no drug release under physiological conditions, the Lapa molecules can induce the reactive oxygen species (ROS) burst specifically in cancer cells via NAD(P)H: quinone oxidoreductase-1 catalysis, which triggers the cleavage of the ether bonds and thus cascade amplification drug release in cancer cells. As a result, the nanoassemblies exhibit much higher cytotoxicity against cancer cells than normal cells, and also increased therapeutic efficacy and reduced side effects compared to the clinically used irinotecan. We anticipate that this strategy can be applied to other drug delivery platforms to enable more precise drug release.

Review on NAD(P)H dehydrogenase quinone 1 (NQO1) pathway

NQO1 is an enzyme present in humans which is encoded by NQO1 gene. It is a protective antioxidant agent, versatile cytoprotective agent and regulates the oxidative stresses of chromatin binding proteins for DNA damage in cancer cells. The oxidization of cellular pyridine nucleotides causes structural alterations to NQO1 and changes in its capacity to binding of proteins. A strategy based on NQO1 to have protective effect against cancer was developed by organic components to enhance NQO1 expression. The quinone derivative compounds like mitomycin C, RH1, E09 (Apaziquone) and β-lapachone causes cell death by NQO1 reduction of two electrons. It was also known to be overexpressed in various tumor cells of breast, lung, cervix, pancreas and colon when it was compared with normal cells in humans. The mechanism of NQO1 by the reduction of FAD by NADPH to form FADH2 is by two ways to inhibit cancer cell development such as suppression of carcinogenic metabolic activation and prevention of carcinogen formation. The NQO1 exhibit suppression of chemical-mediated carcinogenesis by various properties of NQO1 which includes, detoxification of quinone scavenger of superoxide anion radical, antioxidant enzyme, protein stabilizer. This review outlines the NQO1 structure, mechanism of action to inhibit the cancer cell, functions of NQO1 against oxidative stress, drugs acting on NQO1 pathways, clinical significance.

Self-Assembled Amphiphilic Fluorinated Random Copolymers for the Encapsulation and Release of the Hydrophobic Combretastatin A-4 Drug

Water-soluble amphiphilic random copolymers composed of tri(ethylene glycol) methacrylate (TEGMA) or poly(ethylene glycol) methyl ether methacrylate (PEGMA) and perfluorohexylethyl acrylate (FA) were synthesized by ARGET-ATRP, and their self-assembling and thermoresponsive behavior in water was studied by dynamic light scattering (DLS) and UV-vis spectroscopy. The copolymer ability to self-fold in single-chain nano-sized structures (unimer micelles) in aqueous solutions was exploited to encapsulate Combretastatin A-4 (CA-4), which is a very hydrophobic anticancer drug. The cloud point temperature (T_cp) was found to linearly decrease with increasing drug concentration in the drug/copolymer system. Moreover, while CA-4 was preferentially incorporated into the unimer micelles of TEGMA-ran-FA, the drug was found to induce multi-chain, submicro-sized aggregation of PEGMA-ran-FA. Anyway, the encapsulation efficiency was very high (≥81%) for both copolymers. The drug release was evaluated in PBS aqueous solutions both below and above T_cp for TEGMA-ran-FA copolymer and below T_cp, but at two different drug loadings, for PEGMA-ran-FA copolymer. In any case, the release kinetics presented similar profiles, characterized by linear trends up to ≈10–13 h and ≈7 h for TEGMA-ran-FA and PEGMA-ran-FA, respectively. Then, the release rate decreased, reaching a plateau. The release from TEGMA-ran-FA was moderately faster above T_cp than below T_cp, suggesting that copolymer thermoresponsiveness increased the release rate, which occurred anyway by diffusion below T_cp. Cytotoxicity tests were carried out on copolymer solutions in a wide concentration range (5–60 mg/mL) at 37 °C by using Balb/3T3 clone A31 cells. Interestingly, it was found that the concentration-dependent micro-sized aggregation of the amphiphilic random copolymers above T_cp caused a sort of “cellular asphyxiation” with a loss of cell viability clearly visible for TEGMA-ran-FA solutions (T_cp below 37 °C) with higher copolymer concentrations. On the other hand, cells in contact with the analogous PEGMA-ran-FA (T_cp above 37 °C) presented a very good viability (≥75%) with respect to the control at any given concentration.

Two-dimensionalcovalent triazine frameworks as superior nanocarriers for the delivery of thioguanine anti-cancer drugs: a periodic DFT study

This work aims to introduce a superior nanocarrier for thioguanine (TG) anti-cancer drug delivery, drug release, and cancer therapy through computational chemistry.

Beta-Lapachone Attenuates BMSC-Mediated Neuroblastoma Malignant Transformation by Inhibiting Gal-3/Gal-3BP/IL6 Axis

The inflammatory factor IL6 secreted by bone marrow mesenchymal stem cells (BMSCs) in the tumor microenvironment (TME) facilitates the survival and therapeutic resistance of neuroblastoma (NB). Here, we found that IL6 expression in primary tumor tissues or bone marrow (BM) metastases was closely associated with the disease risk and prognosis of NB patients. IL6 secretion from immortalized BMSC (iBMSC) was directly regulated by NB cells and is involved in promoting the proliferation and metastasis of NB cells. Beta-Lapachone (ARQ-501, LPC), an ortho-naphthoquinone natural product, significantly prevented the iBMSC-induced malignant transformation effect on NB cells through suppressing the expression and secretion of IL6 from iBMSC in vitro and in vivo. Mechanistically, LPC disrupted the crosstalk between NB cells and iBMSC in an NQO1-dependent manner through blocking the Gal-3/Gal-3BP/IL6 axis. Our results reveal the effect of iBMSC-derived IL6 on TME-induced malignant transformation of NB cells, and provide theoretical basis for the clinical application of LPC as a potential IL6 inhibitor in high-risk refractory NB patients.

First-principles studies on two-dimensional B3O3 adsorbent as a potential drug delivery platform for TEPA anticancer drug

The remarkable properties of pristine B₃O₃ nanosheet as a nanocarrier for adsorption and desorption of TEPA anticancer drug for designing potential drug delivery platform were investigated using periodic DFT calculations. We studied the adsorption energy of all stable complexes formed between the drug molecule and B₃O₃ in gas and aqueous phases along with electronic structure analysis of complexes. Different adsorption configurations were studied for drug/B₃O₃ complexes, including the interaction of the C atom of the triangular ring, O atom in the TEPA drug with the B atom in B₃O₃, and indirect drug interaction the middle of the R1 ring cavity of the B₃O₃ nanosheet. The take-up of TEPA prompts a substantial change of 68.13% in the band gap (E_g) of the B₃O₃ nanosheet in the most stable complex. The present study results affirmed the application of B₃O₃ nanosheet as a potential vehicle for TEPA drugs in the treatment of cancerous tissues.

Studying the "Rigid-Flexible" Properties of Polymeric Micelle Core-Forming Segments with a Hydrophobic Phthalocyanine Probe Using NMR and UV Spectroscopy

The aim of the performed studies was to thoroughly examine the internal structure of self-assembled nanocarriers (i.e., polymeric micelles-PMs) by means of a hydrophobic phthalocyanine probe in order to identify the crucial features that are required to enhance the photoactive probe stability and reactivity. PMs of hydrophilic poly(ethylene glycol) and hydrophobic poly(ε-caprolactone) (PCL) or poly(d,l-lactide) (PDLLA) were fabricated and loaded with tetra tert-butyl zinc(II) phthalocyanine (ZnPc-t-but₄), a multifunctional spectroscopic probe with a profound ability to generate singlet oxygen upon irradiation. The presence of subdomains, comprising "rigid" and "flexible" regions, in the studied block copolymers' micelles as well as their interactions with the probe molecules, were assessed by various high-resolution NMR measurements [e.g., through-space magnetic interactions by the 1D NOE effect, pulsed field gradient spin-echo, and spin-lattice relaxation time (T₁) techniques]. The studies of the impact of the core-type microenvironment on the ZnPc-t-but₄ photochemical performance also included photobleaching and reactive oxygen species measurements. ZnPc-t-but₄ molecules were found to exhibit spatial proximity effects with both (PCL and PDLLA) hydrophobic polymer chains and interact with both subdomains, which are characterized by different rigidities. It was deduced that the interfaces between particular subdomains constitute an optimal host space for probe molecules, especially in the context of photochemical stability, photoactivity (i.e., for significant enhancement of singlet oxygen generation rates), and aggregation prevention. The present contribution proves that the combination of an appropriate probe, high-resolution NMR techniques, and UV-vis spectroscopy enables one to gain complex information about the subtle structure of PMs essential for their application as nanocarriers for photoactive compounds, for example, in photodynamic therapy, nanotheranostics, combination therapy, or photocatalysis, where the micelles constitute the optimal microenvironment for the desired photoreactions.

Recent Advances in Nanomicelles Delivery Systems

The efficient and selective delivery of therapeutic drugs to the target site remains the main obstacle in the development of new drugs and therapeutic interventions. Up until today, nanomicelles have shown their prospective as nanocarriers for drug delivery owing to their small size, good biocompatibility, and capacity to effectively entrap lipophilic drugs in their core. Nanomicelles are formed via self-assembly in aqueous media of amphiphilic molecules into well-organized supramolecular structures. Molecular weights and structure of the core and corona forming blocks are important properties that will determine the size of nanomicelles and their shape. Selective delivery is achieved via novel design of various stimuli-responsive nanomicelles that release drugs based on endogenous or exogenous stimulations such as pH, temperature, ultrasound, light, redox potential, and others. This review summarizes the emerging micellar nanocarriers developed with various designs, their outstanding properties, and underlying principles that grant targeted and continuous drug delivery. Finally, future perspectives, and challenges for nanomicelles are discussed based on the current achievements and remaining issues.

Assessing the pharmacokinetics and toxicology of polymeric micelle conjugated therapeutics

Introduction: Analogous to nanocarriers such as nanoparticles, liposomes, nano lipoidal carriers, niosomes, and ethosomes, polymeric micelles have gained significance in the field of drug delivery. They have attracted scientists worldwide by their nanometric size, wide range of polymers available for building block synthesis, stability and potential to enhance the targeting and safety of drugs. Incorporation of drugs within the interior of polymeric micelles alters the drug pharmacokinetics, which generally results in increased efficiency.Areas covered: This review deals with the pharmacokinetics of various anti-neoplastic drugs loaded into micelles. The structure of polymeric micelles, polymers employed in their development and techniques involved will be discussed. This is followed by discussion on the pharmacokinetics of anti-cancer drugs loaded into polymeric micelles and the toxicity concerns associated.Expert opinion: Polymeric micelles are nanometeric carriers, with higher stability, polymeric flexibility and higher drug loading of poorly water-soluble drugs. These nanosystems help in increasing the bioavailability of drugs by encapsulating them within the hydrophobic core. The proper selection and design of the amphiphilic polymer for micelles is a crucial step as it decides the toxicity and the biocompatibility.

Recent Advances and Challenges in Controlling the Spatiotemporal Release of Combinatorial Anticancer Drugs from Nanoparticles

To overcome cancer, various chemotherapeutic studies are in progress; among these, studies on nano-formulated combinatorial drugs (NFCDs) are being actively pursued. NFCDs function via a fusion technology that includes a drug delivery system using nanoparticles as a carrier and a combinatorial drug therapy using two or more drugs. It not only includes the advantages of these two technologies, such as ensuring stability of drugs, selectively transporting drugs to cancer cells, and synergistic effects of two or more drugs, but also has the additional benefit of enabling the spatiotemporal and controlled release of drugs. This spatial and temporal drug release from NFCDs depends on the application of nanotechnology and the composition of the combination drug. In this review, recent advances and challenges in the control of spatiotemporal drug release from NFCDs are provided. To this end, the types of combinatorial drug release for various NFCDs are classified in terms of time and space, and the detailed programming techniques used for this are described. In addition, the advantages of the time and space differences in drug release in terms of anticancer efficacy are introduced in depth.

Emerging Nanopharmaceuticals and Nanonutraceuticals in Cancer Management

Nanotechnology is the science of nanoscale, which is the scale of nanometers or one billionth of a meter. Nanotechnology encompasses a broad range of technologies, materials, and manufacturing processes that are used to design and/or enhance many products, including medicinal products. This technology has achieved considerable progress in the oncology field in recent years. Most chemotherapeutic agents are not specific to the cancer cells they are intended to treat, and they can harm healthy cells, leading to numerous adverse effects. Due to this non-specific targeting, it is not feasible to administer high doses that may harm healthy cells. Moreover, low doses can cause cancer cells to acquire resistance, thus making them hard to kill. A solution that could potentially enhance drug targeting and delivery lies in understanding the complexity of nanotechnology. Engineering pharmaceutical and natural products into nano-products can enhance the diagnosis and treatment of cancer. Novel nano-formulations such as liposomes, polymeric micelles, dendrimers, quantum dots, nano-suspensions, and gold nanoparticles have been shown to enhance the delivery of drugs. Improved delivery of chemotherapeutic agents targets cancer cells rather than healthy cells, thereby preventing undesirable side effects and decreasing chemotherapeutic drug resistance. Nanotechnology has also revolutionized cancer diagnosis by using nanotechnology-based imaging contrast agents that can specifically target and therefore enhance tumor detection. In addition to the delivery of drugs, nanotechnology can be used to deliver nutraceuticals like phytochemicals that have multiple properties, such as antioxidant activity, that protect cells from oxidative damage and reduce the risk of cancer. There have been multiple advancements and implications for the use of nanotechnology to enhance the delivery of both pharmaceutical and nutraceutical products in cancer prevention, diagnosis, and treatment.

Nanoparticles and its biomedical applications in health and diseases: special focus on drug delivery

Nanotechnology is an emerging technology that deals with nanosized particles possessing crucial research roles and application. Disciplines like chemistry, biology, physics, engineering, materials science, and health sciences provide an accumulated knowledge of nanotechnology. Nonetheless, it has vast submissions precisely in biology, electronics, and medicine. Aimed at drug delivery system, nanoparticles are based on the mechanism of entrapment of the drugs or biomolecules into the interior structure of the particles; another mechanism could be that the drugs or the biomolecules can be absorbed onto the exterior surfaces of the particles. Currently, nanoparticles (NPs) are used in the delivery of drugs, proteins, genes, vaccines, polypeptides, nucleic acids, etc. In recent years, various applications of the drug delivery system via NPs have encountered an enormous position sector like pharmaceutical, medical, biological, and others. Considering the impact of NPs in drug delivery systems, this review focuses on the detailed profile of NPs, its impact on biology and medicine, and their commercialization prospects.

Assessment of various formulation approaches for the application of beta-lapachone in prostate cancer therapy

Beta-lapachone (β-Lap) is an anticancer drug activated by the NAD(P)H:quinone oxidoreductase (NQO1), an enzyme over-expressed in a large variety of tumors. B-Lap is poorly soluble in water and in most biocompatible solvents. Micellar systems, liposomes and cyclodextrins (CDs) have been proposed for its solubilization. In this work, we analyzed the properties and in vitro efficacy of β-Lap loaded in polymer nanoparticles, liposome bilayers, complexed with sulfobutyl-ether (SBE)- and hydroxypropyl (HP)-β cyclodextrins, or double loaded in phospholipid vesicles. Nanoparticles led to the lowest drug loading. Encapsulation of [β-Lap:CD] complexes in vesicles made it possible to slightly increase the encapsulation rate of the drug in liposomes, however at the cost of poor encapsulation efficiency. Cytotoxicity tests generally showed a higher sensitivity of NIH 3T3 and PNT2 cells to the treatment compared to PC-3 cells, but also a slight resistance at high β-Lap concentrations. None of the studied β-Lap delivery systems showed significant enhanced cytotoxicity against PC-3 cells compared to the free drug. Cyclodextrins and double loaded vesicles, however, appeared more efficient drug delivery systems than liposomes and nanoparticles, combining both good solubilizing and cytotoxic properties. Ligand-functionalized double loaded liposomes might allow overcoming the lack of selectivity of the drug.

Optimized preparation of vinpocetine micelles and in vivo evaluation of its pharmacokinetics in rats

This study aimed to develop a novel monomethoxy poly(ethylene glycol)-b-poly(D, L-lactide) (mPEG₅₀₀₀-PLA_10 000) micelle drug delivery system to improve vinpocetine's (VP) dissolution and sustain VP concentrations in plasma. Three micelle fabrication methods were examined to maximize VP loading, followed by structurally characterization and investigation in vitro release and in vivo pharmacokinetics in Sprague-Dawley rats. The thin-film hydration is the most appropriate method of the three methods because of its high loading content. The loaded micelles exhibited a sustained release behavior up to 48 h. Following intraperitoneal administration (9 mg/kg), VP loaded micelles provided significantly higher (335%) AUC (area under concentration-time) compared to VP injection. And also increased the mean residence time [MRT_(0-t)] and elimination half-life (t_1/2z). There were obviously two peaks at 2 h and 9 h in VP loaded micelles concentration-time profile. In summary, these data demonstrated that poly mPEG-PLA micelles can efficiently sustain VP concentrations in plasma for 36 h, thus apprehending polymeric micelles suitability as poor aqueous solubility drug carriers.

Deciphering the Peculiar Behavior of β-Lapachone in Lipid Monolayers and Bilayers

β-Lapachone (β-Lap) is a promising anticancer drug whose applications have been limited so far because of its poor solubility and stability. Its encapsulation in liposomes has been proposed to overcome these issues. However, surface pressure measurements show that β-Lap exhibits atypical interfacial behavior when mixed with lipids. Although the drug does not seem to be retained in lipid monolayers as deduced from the π-A isotherms, small changes in compressibility moduli suggest that β-Lap actually interacts with lipids, either disorganizing or rigidifying their monolayers. Thermal and structural analyses of lipid bilayers confirm the existence of β-Lap/lipid interactions and show that the drug inserts between hydrophobic chains, close to the polar headgroup in DPPC bilayers and deeper in the acyl chains in POPC bilayers. Molecular dynamics simulations allow a comprehensive description of the drug position and orientation in DOPC and POPC bilayers in the presence or absence of cholesterol.

Cancer Cell Sensitivity to Redox-Cycling Quinones is Influenced by NAD(P)H: Quinone Oxidoreductase 1 Polymorphism

BACKGROUND

Cancer cell sensitivity to drugs may be associated with disturbed antioxidant enzymes expression. We investigated mechanisms of resistance by using oxidative stress-resistant MCF-7 breast cancer cells (Resox cells). Since nicotinamide adenine dinucleotide phosphate (NAD(P)H): quinone oxidoreductase-1 (NQO1) is modified in tumors and oxidative stress-resistant cells, we studied its role in cells exposed to β-lapachone, menadione, and doxorubicin.

METHODS

Normal mammary epithelial 250MK, MCF-7, and Resox cells were employed. NQO1 expression and enzyme activity were determined by quantitative polymerase chain reaction (RT-PCR), immunoblotting, and biochemical assays. Dicoumarol and gene silencing (siRNA) were used to modulate NQO1 expression and to assess its potential drug-detoxifying role. MTT (3-(4,5-dimethylthia-zolyl-2)-2,5-diphenyltetrazolium bromide) or clonogenic assays were used to investigate cytotoxicity. NQO1 variants, NQO1*1 (wt), and NQO1*2 (C609T), were obtained by transfecting NQO1-null MDA-MB-231 cell line.

RESULTS

Resox cells have higher NQO1 expression than MCF-7 cells. In 250MK cells its expression was low but enzyme activity was higher suggesting a variant NQO1 form in MCF-7 cells. MCF-7 and Resox cells are heterozygous NQO1*1 (wt)/ NQO1*2 (C609T). Both NQO1 polymorphism and NQO1 overexpression are main determinants for cell resistance during oxidative stress. NQO1 overexpression increases cell sensitivity to β-lapachone whereas NQO1*2 polymorphism triggers quinone-based chemotherapies-sensitivity.

CONCLUSIONS

NQO1 influences cancer cells redox metabolism and their sensitivity to drugs. We suggest that determining NQO1 polymorphism may be important when considering the use of quinone-based chemotherapeutic drugs.

Tailored Design of an ROS-Responsive Drug Release Platform for Enhanced Tumor Therapy via "Sequential Induced Activation Processes"

The reactive oxygen species (ROS)-responsive intelligent drug delivery system has developed rapidly in recent years. However, because of the low concentration of ROS in most types of tumor cells, it is not possible to rapidly and effectively stimulate the drug delivery system to release the active drug. Here, we introduced "sequential induced activation processes" for efficient tumor therapy by designing a new ROS-responsive drug release platform. β-Lapachone, a positively charged nitrogen mustard (NM) prodrug, and two diblock molecules (mPEG-AcMH and PAsp-AcMH) are self-assembled to form prodrug primary micelles, which are further aggregated into nanoparticles that facilitate drug codelivery. When administered by intravenous injection, the nanoparticles reach the tumor site and enter the tumor cells by endocytosis. The β-lapachone released in the tumor cells induces a large amount of H₂O₂, and the ROS-responsive NM prodrug is activated to form activated NM, quinone methide, and boric acid under the induction of H₂O₂. The activated NM leads to tumor cell apoptosis.

Self-Strengthened Oxidation-Responsive Bioactivating Prodrug Nanosystem with Sequential and Synergistically Facilitated Drug Release for Treatment of Breast Cancer

Although environment-sensitive prodrug-based nanoparticles (NPs) have developed rapidly, lots of prodrug NPs still show poor selectivity and efficiency of parent drug bioactivation because of tumor heterogeneity. Herein, self-strengthened bioactivating prodrug-based NPs are fabricated via co-encapsulation of oxidation-responsive thioether-linked linoleic acid-paclitaxel conjugates (PTX-S-LA) and β-lapachone (LPC) into polymeric micelles (PMs). Following cellular uptake, PMs first release LPC to significantly elevate the reactive oxidative species (ROS) level through NAD(P)H: quinone oxidoreductase-1 (NQO1) catalysis. Then, NQO1-generated ROS in combination with endogenous high ROS levels in tumor cells could synergistically facilitate PTX-S-LA to release the active cytotoxic agent PTX. Such a novel prodrug nanosystem exhibits self-strengthened prodrug bioactivation, ultraselective release, and cytotoxicity between cancer and normal cells, prolonged circulation time, and enhanced tumor accumulation, leading to high antitumor efficiency and superior biosafety. Our findings pave the new way for the rational design of oxidation-responsive prodrug NPs for high-efficacy cancer chemotherapy.

Dual Stimuli-Triggered Nanogels in Response to Temperature and pH Changes for Controlled Drug Release

Poly-N-isopropyl acrylamide (PNIPAM) nanogels have been modified with different acrylic acid (AAc) contents for the efficient control of lower critical solution temperature (LCST). In this study, PNIPAM-co-AAc nanogels nanogels showed two volume phase transitions in comparison with PNIPAM. The transition temperature of PNIPAM nanogels was increased with AAc contents. The controlled drug release performance of PNIPAM-co-AAc nanogels loaded with β-lapachone was attributed to the AAc content ratio and was efficiently triggered in response to temperature and pH. Moreover, a colorimetric cell proliferation assay and direct fluorescence-based live/dead staining were used to confirm the concurrence on drug release profiles. Finally, PNIPAM-co-AAc20 showed a relatively low level of drug release in the range of acidic to neutral pH at body temperature, while maximizing drug release at basic pH. Therefore, we demonstrated that the PNIPAM-based nanogel with the temperature- and pH-responsive features could be a promising nanocarrier for potential intestine-specific drug delivery.

Poly(3-hydroxyalkanoate)-based drug formulations: the micro- and nanostructure

Biodegradable and biocompatible polymers referred to as polyhydroxyalkanoates (PHAs) are extensively used in the production of pharmaceutical drugs to ensure sustained release, targeted delivery, reduced toxicity, and increased stability of the drug substance. Although the pharmaceutical industry ordinarily exploits chemically synthesized PHAs, bioengineered polymers are also starting to enjoy growing interest. This article focuses on the research and development of drug formulations based on natural PHAs that act as auxiliary substances for antibacterial, anti-inflammatory, anticancer, and hormonal medications, as well as pain killers, and discusses the association between their properties and the micro/nano structure of the synthetic drug. The problems associated with the poor performance of active components in traditional dosage forms can be overcome in PHAs-based formulations.

NQO1-dependent, Tumor-selective Radiosensitization of Non-small Cell Lung Cancers

PURPOSE

Development of tumor-specific therapies for the treatment of recalcitrant non-small cell lung cancers (NSCLC) is urgently needed. Here, we investigated the ability of β-lapachone (β-lap, ARQ761 in clinical form) to selectively potentiate the effects of ionizing radiation (IR, 1-3 Gy) in NSCLCs that overexpress NAD(P)H:Quinone Oxidoreductase 1 (NQO1).

EXPERIMENTAL DESIGN

The mechanism of lethality of low-dose IR in combination with sublethal doses of β-lap was evaluated in NSCLC lines in vitro and validated in subcutaneous and orthotopic xenograft models in vivo. Pharmacokinetics and pharmacodynamics (PK/PD) studies comparing single versus cotreatments were performed to validate therapeutic efficacy and mechanism of action.

RESULTS

β-Lap administration after IR treatment hyperactivated PARP, greatly lowered NAD⁺/ATP levels, and increased double-strand break (DSB) lesions over time in vitro. Radiosensitization of orthotopic, as well as subcutaneous, NSCLCs occurred with high apparent cures (>70%), even though 1/8 β-lap doses reach subcutaneous versus orthotopic tumors. No methemoglobinemia or long-term toxicities were noted in any normal tissues, including mouse liver that expresses the highest level of NQO1 (∼12 units) of any normal tissue. PK/PD responses confirm that IR + β-lap treatments hyperactivate PARP activity, greatly lower NAD⁺/ATP levels, and dramatically inhibit DSB repair in exposed NQO1⁺ cancer tissue, whereas low NQO1 levels and high levels of catalase in associated normal tissue were protective.

CONCLUSIONS

Our data suggest that combination of sublethal doses of β-lap and IR is a viable approach to selectively treat NQO1-overexpressing NSCLC and warrant a clinical trial using low-dose IR + β-lap against patients with NQO1⁺ NSCLCs.

Nanomedicines guided nanoimaging probes and nanotherapeutics for early detection of lung cancer and abolishing pulmonary metastasis: Critical appraisal of newer developments and challenges to clinical transition

Lung cancer (LC) is the second most prevalent type of cancer and primary cause of mortality among both men and women, worldwide. The most commonly employed diagnostic modalities for LC include chest X-ray (CXR), magnetic-resonance-imaging (MRI), computed tomography (CT-scan), and fused-positron-emitting-tomography-CT (PET-CT). Owing to several limitations associated with the use of conventional diagnostic tools such as radiation burden to the patient, misleading diagnosis ("missed lung cancer"), false staging and low sensitivity and resolution, contemporary diagnostic regimen needed to be employed for screening of LC. In recent decades, nanotechnology-guided interventions have been transpired as emerging nanoimaging probes for detection of LC at advanced stages, while producing signal amplification, better resolution for surface and deep tissue imaging, and enhanced translocation and biodistribution of imaging probes within the cancerous tissues. Besides enormous potential of nanoimaging probes, nanotechnology-based advancements have also been evidenced for superior efficacy for treatment of LC and abolishing pulmonary metastasis (PM). The success of nanotherapeutics is due to their ability to maximise translocation and biodistribution of anti-neoplastic agents into the tumor tissues, improve pharmacokinetic profiles of anti-metastatic agents, optimise target-specific drug delivery, and control release kinetics of encapsulated moieties in target tissues. This review aims to overview and critically discuss the superiority of nanoimaging probes and nanotherapeutics over conventional regimen for early detection of LC and abolishing PM. Current challenges to clinical transition of nanoimaging probes and therapeutic viability of nanotherapeutics for treatment for LC and PM have also been pondered.

Phase 1 study of ARQ 761, a β-lapachone analogue that promotes NQO1-mediated programmed cancer cell necrosis

BACKGROUND

NAD(P)H:quinone oxidoreductase 1 (NQO1) is a two-electron oxidoreductase expressed in multiple tumour types. ARQ 761 is a β-lapachone (β-lap) analogue that exploits the unique elevation of NQO1 found in solid tumours to cause tumour-specific cell death.

METHODS

We performed a 3+3 dose escalation study of 3 schedules (weekly, every other week, 2/3 weeks) of ARQ 761 in patients with refractory advanced solid tumours. Tumour tissue was analysed for NQO1 expression. After 20 patients were analysed, enrolment was restricted to patients with NQO1-high tumours (H-score ≥ 200).

RESULTS

A total of 42 patients were treated. Median number of prior lines of therapy was 4. Maximum tolerated dose was 390 mg/m² as a 2-h infusion every other week. Dose-limiting toxicity was anaemia. The most common treatment-related adverse events were anaemia (79%), fatigue (45%), hypoxia (33%), nausea (17%), and vomiting (17%). Transient grade 3 hypoxia, reflecting possible methemoglobinaemia, occurred in 26% of patients. Among 32 evaluable patients, best response was stable disease (n = 12); 6 patients had tumour shrinkage. There was a trend towards improved efficacy in NQO1-high tumours (P = 0.06).

CONCLUSIONS

ARQ 761 has modest single-agent activity, which appears associated with tumour NQO1 expression. Principal toxicities include anaemia and possible methemoglobinaemia.

Nanotechnology for Cancer Therapy Based on Chemotherapy

Chemotherapy has been widely applied in clinics. However, the therapeutic potential of chemotherapy against cancer is seriously dissatisfactory due to the nonspecific drug distribution, multidrug resistance (MDR) and the heterogeneity of cancer. Therefore, combinational therapy based on chemotherapy mediated by nanotechnology, has been the trend in clinical research at present, which can result in a remarkably increased therapeutic efficiency with few side effects to normal tissues. Moreover, to achieve the accurate pre-diagnosis and real-time monitoring for tumor, the research of nano-theranostics, which integrates diagnosis with treatment process, is a promising field in cancer treatment. In this review, the recent studies on combinational therapy based on chemotherapy will be systematically discussed. Furthermore, as a current trend in cancer treatment, advance in theranostic nanoparticles based on chemotherapy will be exemplified briefly. Finally, the present challenges and improvement tips will be presented in combination therapy and nano-theranostics.

Investigations on clonazepam-loaded polymeric micelle-like nanoparticles for safe drug administration during pregnancy

Medication during pregnancy is often a necessity for women to treat their acute or chronic diseases. The goal of this study is to evaluate the potential of micelle-like nanoparticles (MNP) for providing safe drug usage in pregnancy and protect both foetus and mother from medication side effects. Clonazepam-loaded MNP were prepared from copolymers [polystyrene-poly(acrylic acid) (PS-PAA), poly(ethylene glycol)-b-poly(lactic acid) (PEG-PLA) and distearyl-sn-glycero-3-phosphoethanolamine-N-[methoxy-poly(ethylene glycol) (PEG-DSPE)] with varying monomer ratios and their drug-loading efficiency, drug release ratio, particle size, surface charge and morphology were characterised. The cellular transport and cytotoxicity experiments were conducted on clonazepam and MNP formulations using placenta-choriocarcinoma-BeWo and brain-endothelial-bEnd3 cells. Clonazepam-loaded PEG₅₀₀₀-PLA₄₅₀₀ MNP reduced the drug transport through BeWo cells demonstrating that MNP may lower foetal drug exposure, thus reduce the drug side effects. However, lipofectamine modified MNP improved the transport of clonazepam and found to be promising for brain and in-utero-specific drug treatment.

Oral bioavailability enhancement of β-lapachone, a poorly soluble fast crystallizer, by cocrystal, amorphous solid dispersion, and crystalline solid dispersion

The aim of this paper was to compare the in vitro dissolution and in vivo bioavailability of three solubility enhancement technologies for β-lapachone (LPC), a poorly water soluble compound with extremely high crystallization propensity. LPC cocrystal was prepared by co-grinding LPC with resorcinol. LPC crystalline and amorphous solid dispersions (CSD and ASD) were obtained by spray drying with Poloxamer 188 and HPMC-AS, respectively. The cocrystal structure was solved by single crystal x-ray diffraction. All formulations were characterized by WAXRD, DSC, POM and SEM. USP II and intrinsic dissolution studies were used to compare the in vitro dissolution of these formulations, and a crossover dog pharmacokinetic study was used to compare their in vivo bioavailability. An 1:1 LPC-resorcinol cocrystal with higher solubility and faster dissolution rate was obtained, yet it converted to LPC crystal rapidly in solution. LPC/HPMC-AS ASD was confirmed to be amorphous and uniform, while the crystal and crystallite sizes of LPC in CSD were found to be ∼1-3 μm and around 40 nm, respectively. These formulations performed similarly during USP II dissolution, while demonstrated dramatically different oral bioavailability of ∼32%, ∼5%, and ∼1% in dogs, for CSD, co-crystal, and ASD, respectively. CSD showed the fastest intrinsic dissolution rate among the three. The three formulations showed poor IVIVC which could be due to rapid and unpredictable crystallization kinetics. Considering all the reasons, we conclude that for molecules with extremely high crystallization tendency that cannot be inhibited by any pharmaceutical excipients, size-reduction technologies such as CSD could be advantageous for oral bioavailability enhancement in vivo than technologies only generating transient but not sustained supersaturation.

Intermolecular Interactions between Coencapsulated Drugs Inhibit Drug Crystallization and Enhance Colloidal Stability of Polymeric Micelles

Novel "pairs" of drugs possessing pharmacological synergies could be encapsulated into polymeric micelles and exert superb therapeutic effects in vivo upon intravenous administration, with the prerequisite that the micelles remain stable. NADP(H) quinone oxidoreductase 1 (NQO1) inhibitors, such as β-lapachone (LPC) and tanshinone IIA (THA), are structurally and pharmacologically similar molecules that are poorly water-soluble, crystallize extremely fast, and demonstrate synergistic anticancer effect when used together with paclitaxel (PTX). However, when coencapsulated with PTX in poly(ethylene glycol)-b-poly(d,l-lactic acid) (PEG-PLA) micelles, only PTX/LPC but not the PTX/THA pair yields satisfactory colloidal stability. To reveal the molecular mechanism contributing to the colloidal stability of the coencapsulated micelles, we investigated the molecular interactions of PTX/LPC and PTX/THA, through both experimental methods (crystallization kinetics, ¹³C NMR) and molecular dynamic simulation. We observed that PTX was capable of inhibiting LPC but not THA crystallization both in an aqueous environment and in the solid state, which could be attributed to the strong hetero-intermolecular interactions (π-π, H-bonding) between LPC and PTX, which disrupted the homo-intermolecular interactions between LPC molecules and thus formed a favorable miscible binary system. In comparison, the lack of a strong PTX/THA interaction left the strong THA/THA stacking interaction undisturbed and the fast THA crystallization tendency unrestrained. We conclude that the intermolecular interactions, i.e., the "pharmaceutical synergy", between the coencapsulated drugs critically control the colloidal stability of polymeric micelles and, therefore, should be evaluated when coencapsulated drug delivery systems are designed for optimal therapeutic benefits.

Protective microencapsulation of β-lapachone using porous glass membrane technique based on experimental optimisation

Even though β-lapachone is a novel drug with pharmacological activity, it has limitations including instability under light conditions. The main purpose of the study was to enhance the stability of β-lapachone using the microencapsulation method. The Shirasu porous glass membrane was used to achieve uniform-sized microcapsules. The prepared microcapsules were evaluated to investigate how process parameters affect the encapsulation efficiency, photostability and particle size distribution. The experimental design was conducted to obtain optimal formulations. In addition, an operating space was drawn to identify the safer range of control factors. All control factors showed significant effects on the encapsulation efficiency and photostability. For example, when a large amount of polymers was used, encapsulation efficiency and photostability were improved. However, as the amount of polymers increased, large and polydisperse microcapsules were produced. The robust design method provided information to characterise significant factors, thereby allowing effective control of photostability and size of microcapsules.

Preparation and Characterizations of RSPP050-Loaded Polymeric Micelles Using Poly(ethylene glycol)-b-Poly(ε-caprolactone) and Poly(ethylene glycol)-b-Poly(D,L-lactide)

RSPP050 (AG50) is one of the semi-synthetic andrographolide that is isolated from Andrographis paniculata NEES (Acanthaceae). The anti-proliferation effects of AG50 against cholangiocarcinoma (HuCCT1) were displayed high cytotoxicity. Unfortunately, poor water solubility of AG50 limited its clinical applications. This study aimed to increase the concentration of AG50 in water and drug loading and release study in phosphate-buffered saline (PBS) in the absence/presence of pig liver esterase enzyme. Cytotoxicity of AG50-loaded polymeric micelles was evaluated against HuCCT1. AG50 loaded micelles were prepared by film sonication and encapsulated by polymers including poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL) or poly(ethylene glycol)-b-poly(D,L-lactide) (PEG-b-PLA). Micelle properties were characterized such as solubility, drug loading, drug release and in vitro cytotoxicity against HuCTT1. AG50 was successfully loaded into both types of polymeric micelles. The best drug-polymer (D/P) ratio was 1 : 9. AG50/PCL and AG50/PLA-micelles had small particle size (36.4±5.1, 49.0±2.7 nm, respectively) and high yield (58.2±1.8, 58.8±2.9, respectively). AG50/PLA-micelles (IC₅₀=2.42 µg/mL) showed higher cytotoxicity against HuCCT1 than AG50/PCL-micelles (IC₅₀=4.40 µg/mL) due to the higher amount of AG50 released. Nanoencapsulation of AG50 could provide a promising development in clinical use for cholangiocarcinoma treatment.

Drug-Loaded Polymeric Nanoparticles for Cancer Stem Cell Targeting

Cancer stem cells (CSCs) have been reported to play critical roles in tumor initiation, propagation, and regeneration of cancer. Nano-size vehicles are employed to deliver drugs to target the CSCs for cancer therapy. Polymeric nanoparticles have been considered as the most efficient vehicles for drug delivery due to their excellent pharmacokinetic properties. The CSCs specific antibodies or ligands can be conjugated onto the surface or interior of nanoparticles to successfully target and finally eliminate CSCs. In this review, we focus on the approaches of polymeric nanoparticles design for loading drug, and their potential application for CSCs targeting in cancer therapy.