Targeting nitric oxide for cancer therapy

Chromium Complex of Macrocyclic Ligands as Precursor for Nitric Oxide Release: A Theoretical Study

Our research on the chromium complex of macrocyclic ligands as a precursor for nitric oxide release makes a significant contribution to the field of chemistry. We conduct a detailed analysis of nitrito chromium complexes, specifically trans-[M(III)L1-5(ONO)2]+, where M=Cr(III) and L1-L5 represent different ligands such as L1=1,4,8,11-tetraazacyclotetradecane, L2= (5,7-dimethyl-6-benzylcyclam), L3= (5,7-dimethyl-6-anthracylcyclam), L4= (5,7-dimethyl-6-(p-hydroxymethylbenzyl)-1,4, 8,11-cyclam) and L5= (5,7-dimethyl-6-(1¢-methyl-4'-(1"-carboxymethylpyrene) benzyl)-1,4,8,11-tetraazacyclotetradecane). Our objective is to comprehensively understand the mechanism of NO release and identify the key factors influencing NO delivery. The optimized structure of the complexes at spin states S=1/2 or 3/2 indicates a decrease in the Cr(III)-O bond length (1.669-1.671 Å) along with an increase in the Cr(III)O-NO bond length (2.735-2.741 Å), which facilitates the release of NO. Furthermore, there is a significant change in the bond angle (Cr-O-NO), from 120.4° to 116.9°, to S=3/2, thus enlarging the O-NO bond and supporting the β-cleavage of NO from the complex. The calculated activation energy for the complexes reflects the energy difference between the low-spin doublet and high-spin quartet state due to spin crossover (SCO). Moreover, the Natural Transition Orbitals (NTOs) confirm the involvement of a hole-particle in the excitation. Additionally, TD-DFT reveals the pendant chromophore's role in generating NO, as the chromophore antenna effectively enhances light absorption.

Synthesis, structure, spectra, cytotoxicity and photo induced NO release of four isomeric nitrosylruthenium complexes

Four isomeric nitrosyl ruthenium complexes [RuCl(2mqn)(Val)(NO)] (1-4) were prepared (2mqn, 2-methyl-8-hydroxyquinoline; Val, l-valine) and characterized by 1H NMR, 13C NMR, absorption spectrum, electrospray ionization mass spectrometry, and X-ray crystal diffraction. Time-resolved FT-IR and fluorescence spectroscopy were used to monitor photo-induced NO release in solution, while NO released in living cells was imaged using a selective fluorescent probe. The isomeric complexes showed different levels of cytotoxicity against HeLa cells, and slightly photo-enhanced anti-proliferative activity was observed. The isomeric complexes 1-4 inhibited the growth of HeLa cells by inducing apoptosis and promoted cell cycle arrest in the S phase. Furthermore, they showed relatively lower cytotoxicity against the human liver cell line HL-7702. The different spatial configurations of the complexes is close related with the selective binding of the isomeric complexes with serum albumin, which provide insight into the potential applications of the nitrosyl ruthenium complexes.

Nitric Oxide Photorelease from Silicone Films Doped with N-Nitroso BODIPY

Nitric oxide (NO) is a unique biochemical mediator involved in the regulation of vital processes. Light-controllable NO releasers show promise in the development of smart therapies. Here, we present a novel biocompatible material based on polydimethylsiloxane (PDMS) doped with BODIPY derivatives containing an N-nitroso moiety that is capable of the photoinduced generation of NO. We study the green-light-induced NO-release properties with the following three methods: electrochemical gas-phase sensor, liquid-phase sensor, and the Griess assay. Prolonged release of NO from the polymer films after short irradiation by narrow-band LED light sources and a laser beam is demonstrated. Importantly, this was accompanied by no or little release of the parent compound (BODIPY-based photodonor). Silicone films with the capability of controllable and clean NO release can potentially be used as a highly portable NO delivery system for different therapeutic applications.

Plasma-Activated Media Produced by a Microwave-Excited Atmospheric Pressure Plasma Jet Is Effective against Cisplatin-Resistant Human Bladder Cancer Cells In Vitro

Media exposed to atmospheric pressure plasma (APP) produce reactive oxygen and nitrogen species (RONS), with hydrogen peroxide (H2O2), nitrite (NO2-), and nitrate (NO3-) being among the most detected species due to their relatively long lifetime. In this study, a standardized microwave-excited (ME) APP jet (APPJ) source was employed to produce gaseous RONS to treat liquid samples. The source was a commercially available plasma jet, which generated argon plasma utilizing a coaxial transmission line resonator at the operating frequency of 2.45 GHz. An ultraviolet-visible spectrophotometer was used to measure the concentrations of H2O2 and NO3- in plasma-activated media (PAM). Three different types of media (deionized water, Hank's balanced salt solution, and cell culture solution Dulbecco's modified eagles medium [DMEM]) were utilized as liquid samples. Among these media, the plasma-treated DMEM was observed to have the highest levels of H2O2 and NO3-. Subsequently, the feasibility of using argon ME-APPJ-activated DMEM (PAM) as an adjuvant to enhance the therapeutic effects of cisplatin on human bladder cancer cells (T-24) was investigated. Various cancer cell lines, including T-24 cells, treated with PAM were observed in vitro for changes in cell viability using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. A viability reduction was detected in the various cancer cells after incubation in PAM. Furthermore, the study's results revealed that PAM was effective against cisplatin-resistant T-24 cells in vitro. In addition, a possible connection between HER expression and cell viability was sketched.

Recent Progress and Trends in X-ray-Induced Photodynamic Therapy with Low Radiation Doses

The prominence of photodynamic therapy (PDT) in treating superficial skin cancer inspires innovative solutions for its congenitally deficient shadow penetration of the visible-light excitation. X-ray-induced photodynamic therapy (X-PDT) has been proven to be a successful technique in reforming the conventional PDT for deep-seated tumors by creatively utilizing penetrating X-rays as external excitation sources and has witnessed rapid developments over the past several years. Beyond the proof-of-concept demonstration, recent advances in X-PDT have exhibited a trend of minimizing X-ray radiation doses to quite low values. As such, scintillating materials used to bridge X-rays and photosensitizers play a significant role, as do diverse well-designed irradiation modes and smart strategies for improving the tumor microenvironment. Here in this review, we provide a comprehensive summary of recent achievements in X-PDT and highlight trending efforts using low doses of X-ray radiation. We first describe the concept of X-PDT and its relationships with radiodynamic therapy and radiotherapy and then dissect the mechanism of X-ray absorption and conversion by scintillating materials, reactive oxygen species evaluation for X-PDT, and radiation side effects and clinical concerns on X-ray radiation. Finally, we discuss a detailed overview of recent progress regarding low-dose X-PDT and present perspectives on possible clinical translation. It is expected that the pursuit of low-dose X-PDT will facilitate significant breakthroughs, both fundamentally and clinically, for effective deep-seated cancer treatment in the near future.

Anti-breast cancer sinomenine derivatives via mechanisms of apoptosis induction and metastasis reduction

Sinomenine, a morphinane-type isoquinoline-derived alkaloid, was first isolated from stems and roots of Sinomenium diversifolius (Miq.) in 1920. Later discovery by researchers confirmed various essential biological efficacy sinomenine exerted in vitro and in vivo. In this study, a series of 15 sinomenine/furoxan hybrid compounds were designed and synthesised in search of a TNBC drug candidate. Some of the target compounds exhibited strong antiproliferative activities against cancer cell lines, especially for TNBC cells, compared to positive controls. Among them, hybrid 7Cc exerted superior cytotoxic effects on cancer cell lines with exceptionally low IC₅₀ (0.82 μM) against MDA-MB-231 cells with the highest safety index score. Further studies in mechanism displayed that 7Cc could induce an S phase cell cycle arrest, stimulate apoptosis in MDA-MB-231 cells, disrupt mitochondrial membrane potential and exert a genotoxic effect on DNA in cancer cells. In addition, 7Cc also notably inhibited MDA-MB-231 cells in both migration, invasion and adhesion.

Opportunities for Nitric Oxide in Potentiating Cancer Immunotherapy

Despite nearly 30 years of development and recent highlights of nitric oxide (NO) donors and NO delivery systems in anticancer therapy, the limited understanding of exogenous NO's effects on the immune system has prevented their advancement into clinical use. In particular, the effects of exogenously delivered NO differing from that of endogenous NO has obscured how the potential and functions of NO in anticancer therapy may be estimated and exploited despite the accumulating evidence of NO's cancer therapy-potentiating effects on the immune system. After introducing their fundamentals and characteristics, this review discusses the current mechanistic understanding of NO donors and delivery systems in modulating the immunogenicity of cancer cells as well as the differentiation and functions of innate and adaptive immune cells. Lastly, the potential for the complex modulatory effects of NO with the immune system to be leveraged for therapeutic applications is discussed in the context of recent advancements in the implementation of NO delivery systems for anticancer immunotherapy applications. SIGNIFICANCE STATEMENT: Despite a 30-year history and recent highlights of nitric oxide (NO) donors and delivery systems as anticancer therapeutics, their clinical translation has been limited. Increasing evidence of the complex interactions between NO and the immune system has revealed both the potential and hurdles in their clinical translation. This review summarizes the effects of exogenous NO on cancer and immune cells in vitro and elaborates these effects in the context of recent reports exploiting NO delivery systems in vivo in cancer therapy applications.

The Nitric Oxide Donor [Zn(PipNONO)Cl] Exhibits Antitumor Activity through Inhibition of Epithelial and Endothelial Mesenchymal Transitions

Simple Summary

Nitric oxide (NO) plays a critical pathophysiological role in cancer by modulating several processes, such as angiogenesis, tumor growth, and metastatic potential. The aim of this study was to characterize the antitumor effects of a novel NO donor, [Zn(PipNONO)Cl], on the processes of epithelial– and endothelial–mesenchymal transitions (EMT and EndMT), known to actively participate in cancer progression. Two tumor cells lines were used in this study: human lung cancer cells (A549) and melanoma cells (A375), alone and co-cultured with human endothelial cells. Our results demonstrate that both tumor and endothelial cells were targets of NO action, which impaired EMT and EndMT functional and molecular features. Further studies are needed to finalize the therapeutic use of the novel NO donor.

Abstract

Exogenous nitric oxide appears a promising therapeutic approach to control cancer progression. Previously, a nickel-based nonoate, [Ni(SalPipNONO)], inhibited lung cancer cells, along with impairment of angiogenesis. The Zn(II) containing derivatives [Zn(PipNONO)Cl] exhibited a protective effect on vascular endothelium. Here, we have evaluated the antitumor properties of [Zn(PipNONO)Cl] in human lung cancer (A549) and melanoma (A375) cells. Metastasis initiates with the epithelial–mesenchymal transition (EMT) process, consisting of the acquisition of invasive and migratory properties by tumor cells. At not cytotoxic levels, the nonoate significantly impaired A549 and A375 EMT induced by transforming growth factor-β1 (TGF-β1). Reduction of the mesenchymal marker vimentin, upregulated by TGF-β1, and restoration of the epithelial marker E-cadherin, reduced by TGF-β1, were detected in both tumor cell lines in the presence of Zn-nonoate. Further, the endothelial–mesenchymal transition achieved in a tumor-endothelial cell co-culture was assessed. Endothelial cells co-cultured with A549 or A375 acquired a mesenchymal phenotype with increased vimentin, alpha smooth muscle actin and Smad2/3, and reduced VE-cadherin. The presence of [Zn(PipNONO)Cl] maintained a typical endothelial phenotype. In conclusion, [Zn(PipNONO)Cl] appears a promising therapeutic tool to control tumor growth and metastasis, by acting on both tumor and endothelial cells, reprogramming the cells toward their physiologic phenotypes.

GSH-Responsive Metal-Organic Framework for Intratumoral Release of NO and IDO Inhibitor to Enhance Antitumor Immunotherapy

Immunotherapy brings great benefits for tumor therapy in clinical treatments but encounters the severe challenge of low response rate mainly because of the immunosuppressive tumor microenvironment. Multifunctional nanoplatforms integrating effective drug delivery and medical imaging offer tremendous potential for cancer treatment, which may play a critical role in combinational immunotherapy to overcome the immunosuppressive microenvironment for efficient tumor therapy. Here, a nanodrug (BMS-SNAP-MOF) is prepared using glutathione (GSH)-sensitive metal-organic framework (MOF) to encapsulate an immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO) inhibitor BMS-986205, and the nitric oxide (NO) donor s-nitrosothiol groups. The high T1 relaxivity allows magnetic resonance imaging to monitor nanodrug distribution in vivo. After the nanodrug accumulation in tumor tissue via the EPR effect and subsequent internalization into tumor cells, the enriched GSH therein triggers cascade reactions with MOF, which disassembles the nanodrug to rapidly release the IDO-inhibitory BMS-986205 and produces abundant NO. Consequently, the IDO inhibitor and NO synergistically modulate the immunosuppressive tumor microenvironment with increase CD8⁺ T cells and reduce Treg cells to result in highly effective immunotherapy. In an animal study, treatment using this theranostic nanodrug achieves obvious regressions of both primary and distant 4T1 tumors, highlighting its application potential in advanced tumor immunotherapy.

Photothermal/NO combination therapy from plasmonic hybrid nanotherapeutics against breast cancer

In this study, a plasmon-semiconductor nanotheranostic system comprising Au nanostars/graphene quantum dots (AuS/QD) hybrid nanoparticles loaded with BNN6 and surface modified with PEG-pyrene was developed for the photo-triggered hyperthermia effect and NO production as the dual modality treatment against orthotopic triple-negative breast cancer. The structure and morphology of the hybrid nanodevice was characterized and the NIR-II induced thermal response and NO production was determined. The hybrid nanodevice has shown enhanced plasmonic energy transfer from localized surface plasmonic resonance of Au nanostars to QD semiconductor that activates the BNN6 species loaded on QD surfaces, leading to the effective NO production and the gas therapy in addition to the photothermal response. The increased accumulation of the NIR-II-responsive hybrid nanotheranostic in tumor via the enhanced permeation and retention effects was confirmed by both in vivo fluorescence and photoacoustic imaging. The prominent therapeutic efficacy of the photothermal/NO combination therapy from the BNN6-loaded AuS@QD nanodevice with the NIR-II laser irradiation at 1064 nm against 4T1 breast cancer was observed both in vitro and in vivo. The NO therapy for the cancer treatment was evidenced with the increased cellular nitrosative and oxidative stress, nitration of tyrosine residues of mitochondrial proteins, vessel eradication and cell apoptosis. The efficacy of the photothermal treatment was corroborated directly by severe tissue thermal ablation and tumor growth inhibition. The NIR-II triggered thermal/NO combination therapy along with the photoacoustic imaging-guided therapeutic accumulation in tumor shows prominent effect to fully inhibit tumor growth and validates the promising strategy developed in this study.

Ruthenium-nitrosyl complexes as NO-releasing molecules and potential anticancer drugs

The synthesis of new types of mono- and polynuclear ruthenium nitrosyl complexes is driving progress in the field of NO generation for a variety of applications. Light-induced Ru-NO bond dissociation...

Structural and Photodynamic Studies on Nitrosylruthenium-Complexed Serum Albumin as a Delivery System for Controlled Nitric Oxide Release

How to deliver nitric oxide (NO) to a physiological target and control its release quantitatively is a key issue for biomedical applications. Here, a water-soluble nitrosylruthenium complex, [(CH₃)₄N][RuCl₃(5cqn)(NO)] (H5cqn = 5-chloro-8-quinoline), was synthesized, and its structure was confirmed with ¹H NMR and X-ray crystal diffraction. Photoinduced NO release was investigated with time-resolved Fourier transform infrared and electron paramagnetic resonance (EPR) spectroscopies. The binding constant of the [RuCl₃(5cqn)(NO)]^- complex with human serum albumin (HSA) was determined by fluorescence spectroscopy, and the binding mode was identified by X-ray crystallography of the HSA and Ru-NO complex adduct. The crystal structure reveals that two molecules of the Ru-NO complex are located in the subdomain IB, which is one of the major drug binding regions of HSA. The chemical structures of the Ru complexes were [RuCl₃(5cqn)(NO)]^- and [RuCl₃(Glycerin)NO]^-, in which the electron densities for all ligands to Ru are unambiguously identified. EPR spin-trapping data showed that photoirradiation triggered NO radical generation from the HSA complex adduct. Moreover, the near-infrared image of exogenous NO from the nitrosylruthenium complex in living cells was observed using a NO-selective fluorescent probe. This study provides a strategy to design an appropriate delivery system to transport NO and metallodrugs in vivo for potential applications.

Synthesis, Characterization, and Reactivity of a Hypervalent-Iodine-Based Nitrooxylating Reagent

Herein, the synthesis and characterization of a hypervalent-iodine-based reagent that enables a direct and selective nitrooxylation of enolizable C-H bonds to access a broad array of organic nitrate esters is reported. This compound is bench stable, easy-to-handle, and delivers the nitrooxy (-ONO₂ ) group under mild reaction conditions. Activation of the reagent by Brønsted and Lewis acids was demonstrated in the synthesis of nitrooxylated β-keto esters, 1,3-diketones, and malonates, while its activity under photoredox catalysis was shown in the synthesis of nitrooxylated oxindoles. Detailed mechanistic studies including pulse radiolysis, Stern-Volmer quenching studies, and UV/Vis spectroelectrochemistry reveal a unique single-electron-transfer (SET)-induced concerted mechanistic pathway not reliant upon generation of the nitrate radical.

Porphyrin-Based Metal-Organic Framework Compounds as Promising Nanomedicines in Photodynamic Therapy

Porphyrin photosensitizers are widely used in photodynamic therapy (PDT) because of their unique diagnostic and therapeutic functions. However, many factors such as poor water solubility and instability of porphyrin compounds have limited their clinical application. Metal-organic frameworks (MOFs) have the beneficial characteristics of versatility, high porosity, and excellent biocompatibility. Porphyrin-MOF nanomaterials have attracted the attention of researchers because MOFs can effectively suppress the quenching caused by the self-aggregation of porphyrin compounds and promote drug delivery. This article reviews the latest applications of porphyrin-MOF nanomedicine in type II photodynamic therapy by increasing tumour cell oxygen concentration, depleting tumour cell functional molecules and releasing signal molecules. Current potential limitations and future applications are also emphasized and discussed herein.

Melanoma Growth Analysis in Blood Serum and Tissue Using Xenograft Model with Response to Cold Atmospheric Plasma Activated Medium

Background: Cold atmospheric plasma (CAP) proposed as a novel therapeutic tool for the various kinds of cancer treatment. Cold atmospheric Plasma-Activated Media (PAM) has exhibited its promising application in plasma medicine for the treatment of cancer. Methods: We investigated the role of PAM on the human melanoma cancer G-361 cells xenograft in vivo by estimating the biochemical and gene expression of apoptotic genes. Results: Reactive oxygen and nitrogen species (RONS) generated by PAM could significantly decrease the tumor volume (40%) and tumor weight (26%) when administered intradermally (i.d.) into the melanoma region continuously for three days. Biochemical studies in blood serum along with excised melanoma samples revealed an increase in protein carbonylation and MDA content as compared to the control, while LDH and L-DOPA in serum and melanoma tissues were decreased significantly in PAM treated group. PAM generated RONS increased apoptotic genes like Bcl-2, Bax, Parp, Casp8, and P53 in melanoma tissue. Immunohistochemistry data confirms that PAM treatment increased apoptosis at the tissue level. Conclusions: These results suggested that RONS present in PAM inhibit the induction of xenograft melanoma cancer cells through the induction of apoptosis and upregulating of various biochemical parameters within blood serum and melanoma.

Anti-CD24 Antibody-Nitric Oxide Conjugate Selectively and Potently Suppresses Hepatic Carcinoma

Nitric oxide (NO) has a wide range of potential applications in tumor therapy. However, a targeted delivery system for NO donors has remained elusive, creating a bottleneck that limits its druggability. The antibody-drug conjugate (ADC) is a targeted drug delivery system composed of an antibody linked to an active cytotoxic drug. This design may compensate for the weak targeting ability and various biological functions of the NO donor. In this study, we designed the NO donor HL-2, which had a targeted, cleaved disulfide bond and an attachable maleimide terminal. We conjugated HL-2 with an antibody that targeted CD24 through a thioether bond to generate an ADC-like immunoconjugate, antibody-nitric oxide conjugate (ANC), which we named HN-01. HN-01 showed efficient internalization and significantly increased the release of NO in hepatic carcinoma cells in vitro. HN-01 induced apoptosis of tumor cells and suppressed tumor growth in hepatic carcinoma-bearing nude mice through antibody-dependent co-toxicity; HN-01 also increased NO levels in tumor cells. Collectively, this study expands the concept of ADC and provides an innovative NO donor and ANC to address current challenges in targeted delivery of NO. This new inspiration for an ANC design can also be used in future studies for other molecules with intracellular targets. SIGNIFICANCE: This study is the first to expand the concept of ADC with an antibody-nitric oxide conjugate that suppresses hepatic carcinoma in vitro and in vivo.

Controlled Delivery of Nitric Oxide for Cancer Therapy

Nitric oxide (NO) is a short-lived, endogenously produced, signaling molecule which plays multiple roles in mammalian physiology. Underproduction of NO is associated with several pathological processes; hence a broad range of NO donors have emerged as potential therapeutics for cardiovascular and respiratory disorders, wound healing, the immune response to infection, and cancer. However, short half-lives, chemical reactivity, rapid systemic clearance, and cytotoxicity have hindered the clinical development of most low molecular weight NO donors. Hence, for controlled NO delivery, there has been extensive effort to design novel NO-releasing biomaterials for tumor targeting. This review covers the effects of NO in cancer biology, NO releasing moieties which can be used for NO delivery, and current advances in the design of NO releasing biomaterials focusing on their applications for tumor therapy.

A cyotosol-selective nitric oxide bomb as a new paradigm of an anticancer drug

Dual pH and redox-sensitive polymeric NO delivery micelles act as a cytosol-selective NO bomb for efficient anticancer therapy.

Near-Infrared Photoactivatable Nitric Oxide Donors with Integrated Photoacoustic Monitoring

Photoacoustic (PA) tomography is a noninvasive technology that utilizes near-infrared (NIR) excitation and ultrasonic detection to image biological tissue at centimeter depths. While several activatable small-molecule PA sensors have been developed for various analytes, the use of PA molecules for deep-tissue analyte delivery and monitoring remains an underexplored area of research. Herein, we describe the synthesis, characterization, and in vivo validation of photoNOD-1 and photoNOD-2, the first organic, NIR-photocontrolled nitric oxide (NO) donors that incorporate a PA readout of analyte release. These molecules consist of an aza-BODIPY dye appended with an aryl N-nitrosamine NO-donating moiety. The photoNODs exhibit chemostability to various biological stimuli, including redox-active metals and CYP450 enzymes, and demonstrate negligible cytotoxicity in the absence of irradiation. Upon single-photon NIR irradiation, photoNOD-1 and photoNOD-2 release NO as well as rNOD-1 or rNOD-2, PA-active products that enable ratiometric monitoring of NO release. Our in vitro studies show that, upon irradiation, photoNOD-1 and photoNOD-2 exhibit 46.6-fold and 21.5-fold ratiometric turn-ons, respectively. Moreover, unlike existing NIR NO donors, the photoNODs do not require encapsulation or multiphoton activation for use in live animals. In this study, we use PA tomography to monitor the local, irradiation-dependent release of NO from photoNOD-1 and photoNOD-2 in mice after subcutaneous treatment. In addition, we use a murine model for breast cancer to show that photoNOD-1 can selectively affect tumor growth rates in the presence of NIR light stimulation following systemic administration.

Design, synthesis and biological evaluation of novel ferrocene-pyrazole derivatives containing nitric oxide donors as COX-2 inhibitors for cancer therapy

A series of novel ferrocene-pyrazole derivatives containing nitric oxide donors as COX-2 inhibitors for cancer therapy were designed, synthesized and biologically evaluated. Among them, compound 7l displayed the most potent inhibitory against COX-2 (IC₅₀ = 0.82 μM) and antiproliferative activities against Hela cells (IC₅₀ = 0.34 μM) compared with Celecoxib (IC₅₀ = 0.38 and 7.91 μM). The further mechanistic studies revealed that 7l could induce apoptosis of Hela cells by mitochondrial depolarization and the antiproliferative activities of 7l were positively correlated with the levels of intracellular NO release in Hela cells. Most notably, 7l could dramatically suppress tumor growth in Hela cells xenografted mouse model. In summary, compound 7l may be promising candidates for cancer therapy.

Targeting the mitochondrial VDAC in hepatocellular carcinoma using a polyclonal antibody-conjugated to a nitrosyl ruthenium complex

The rational design of anti-cancer agents includes a new approach based on ruthenium complexes that can act as nitric oxide (NO) donor agents against specific cellular targets. One of the most studied classes of those compounds is based on bis(bipyridine) ruthenium fragment and its derivative species. In this work, we present the chemical and cytotoxicity properties against the liver hepatocellular carcinoma cell line HepG2 of cis-[RuII(NO+)Cl(dcbpy)2]2- conjugated to a polyclonal antibody IgG (anti-VDAC) recognizing a cell surface marker. UV-visible bands of the ruthenium complex were assigned with the aid of density functional theory, which also allowed estimation of the structures that explain the biological effects of the ruthenium complex-IgG conjugate. The interaction of cis-[RuII(NO+)Cl(dcbpy)2]3- with mitochondria was evaluated due to the potential of these organelles as anti-cancer targets, and considering they interact with the anti-VDAC antibody. The cytotoxicity of cis-[RuII(NO+)Cl(dcbpy)2]3--anti-VDAC antibody was up to 80% greater in comparison to the free cis-[RuII(NO+)Cl(dcbpy)2]3- complex. We suggest that this effect is due to site-specific interaction of the complex followed by NO release.

Medical applications of nonthermal atmospheric pressure plasma in dermatology

Plasma is an ionized gas that consists of positively and negatively charged particles, neutral atoms, and photons. Recent developments in plasma sources have made it possible to generate room-temperature plasma in the "open air", thus enabling the application of plasma in vivo. Using nonthermal plasma, active agents can be efficiently delivered to target cells without creating thermal damage. Also known as cold atmospheric pressure plasma (CAP), nonthermal atmospheric pressure plasma offers innovative medical applications. In this context, it has also gained wide attention in the field of dermatology. The complex and variable mixture of active agents in plasma - predominantly reactive oxygen and nitrogen species (ROS, RNS) - can control or trigger complex biochemical reactions, achieving the desired effects in a dose-dependent manner. The objective of the present review is to present potential applications of plasma in dermatology and analyze its potential mechanisms of action.

Research progress in modern structure of platinum complexes

Since the antitumor activity of cisplatin was discovered in 1967 by Rosenberg, platinum-based anticancer drugs have played an important role in chemotherapy in clinic. Nevertheless, platinum anticancer drugs also have caused severe side effects and cross drug resistance which limited their applications. Therefore, a significant amount of efforts have been devoted to developing new platinum-based anticancer agents with equal or higher antitumor activity but lower toxicity. Until now, a large number of platinum-based complexes have been prepared and extensively investigated in vitro and in vivo. Among them, some platinum-based complexes revealing excellent anticancer activity showed the potential to be developed as novel type of anticancer agents. In this account, we present such platinum-based anticancer complexes which owning various types of ligands, such as, amine carrier ligands, leaving groups, reactive molecule, steric hindrance groups, non-covalently binding platinum (II) complexes, Platinum(IV) complexes and polynuclear platinum complexes. Overall, platinum-based anticancer complexes reported recently years upon modern structure are emphasized.

Discovery of phosphorodiamidate mustard-based O2-phosphorylated diazeniumdiolates with potent anticancer activity

Diazeniumdiolates are an important class of NO donors. Herein, we describe the design, synthesis and biological evaluation of a group of phosphorodiamidate mustard-based O²-phosphorylated diazeniumdiolates.

Design, Synthesis, and Evaluation of Diazeniumdiolate-Based DNA Cross-Linking Agents Activatable by Glutathione S-Transferase

A novel class of O²-(2,4-dinitrophenyl)-1-[N,N-bis(2-substituted ethyl)amino]diazen-1-ium-1,2-diolates 4-6 were designed, synthesized, and biologically evaluated. The most active compound 6 caused significant DNA damage by releasing N,N-bis(2-TsO ethyl)amine and two molecules of nitric oxide (NO) after activation by GST/GSH in cancer cells, being more cytotoxic against three cancer cell lines than a well-known diazeniumdiolate-based anticancer agent JS-K, suggesting that the strategy has potential to extend to other O²-derived diazeniumdiolates to improve anticancer activity.

In Vitro Metabolic Stability and in Vivo Biodistribution of 3-Methyl-4-furoxancarbaldehyde Using PET Imaging in Rats

Painful diabetic neuropathy (PDN) is a type of peripheral neuropathic pain that is currently difficult to treat using clinically available analgesics. Recent work suggests a progressive depletion of nitric oxide (NO) in nerve cells may be responsible for the pathobiology of PDN. The nitric oxide donor, 3-methyl-4-furoxancarbaldehyde (PRG150), has been shown to produce dose-dependent analgesia in a rat model of PDN. To gain insight into the mechanism of analgesia, methods to radiolabel PRG150 were developed to assess the in vivo biodistribution in rats. The furoxan ring was labeled with (13)N to follow any nitric oxide release and the 3-methyl substituent was labeled with (11)C to track the metabolite using PET imaging. The in vitro metabolic stability of PRG150 was assessed in rat liver microsomes and compared to in vivo metabolism of the synthesized radiotracers. PET images revealed a higher uptake of (13)N over (11)C radioactivity in the spinal cord. The differences in radioactive uptake could indicate that a NO release in the spinal cord and other components of the somatosensory nervous system may be responsible for the analgesic effects of PRG150 seen in the rat model of PDN.

Synergistic Effect of Cold Atmospheric Plasma and Drug Loaded Core-shell Nanoparticles on Inhibiting Breast Cancer Cell Growth

Nano-based drug delivery devices allowing for effective and sustained targeted delivery of therapeutic agents to solid tumors have revolutionized cancer treatment. As an emerging biomedical technique, cold atmospheric plasma (CAP), an ionized non-thermal gas mixture composed of various reactive oxygen species, reactive nitrogen species, and UV photons, shows great potential for cancer treatment. Here we seek to develop a new dual cancer therapeutic method by integrating promising CAP and novel drug loaded core-shell nanoparticles and evaluate its underlying mechanism for targeted breast cancer treatment. For this purpose, core-shell nanoparticles were synthesized via co-axial electrospraying. Biocompatible poly (lactic-co-glycolic acid) was selected as the polymer shell to encapsulate anti-cancer therapeutics. Results demonstrated uniform size distribution and high drug encapsulation efficacy of the electrosprayed nanoparticles. Cell studies demonstrated the effectiveness of drug loaded nanoparticles and CAP for synergistic inhibition of breast cancer cell growth when compared to each treatment separately. Importantly, we found CAP induced down-regulation of metastasis related gene expression (VEGF, MTDH, MMP9, and MMP2) as well as facilitated drug loaded nanoparticle uptake which may aid in minimizing drug resistance-a major problem in chemotherapy. Thus, the integration of CAP and drug encapsulated nanoparticles provides a promising tool for the development of a new cancer treatment strategy.

Low temperature plasmas as emerging cancer therapeutics: the state of play and thoughts for the future

The field of plasma medicine has seen substantial advances over the last decade, with applications developed for bacterial sterilisation, wound healing and cancer treatment. Low temperature plasmas (LTPs) are particularly suited for medical purposes since they are operated in the laboratory at atmospheric pressure and room temperature, providing a rich source of reactive oxygen and nitrogen species (RONS). A great deal of research has been conducted into the role of reactive species in both the growth and treatment of cancer, where long-established radio- and chemo-therapies exploit their ability to induce potent cytopathic effects. In addition to producing a plethora of RONS, LTPs can also create strong electroporative fields. From an application perspective, it has been shown that LTPs can be applied precisely to a small target area. On this basis, LTPs have been proposed as a promising future strategy to accurately and effectively control and eradicate tumours. This review aims to evaluate the current state of the literature in the field of plasma oncology and highlight the potential for the use of LTPs in combination therapy. We also present novel data on the effect of LTPs on cancer stem cells, and speculatively outline how LTPs could circumvent treatment resistance encountered with existing therapeutics.

trans- and cis-(Cl,Cl)-[RuII(FT)Cl2(NO)](PF6): promising candidates for NO release in the NIR region

Efficient NO photodelivery from cis- and trans-(Cl,Cl)-[Ru^II(FT)Cl₂(NO)](PF₆) complexes upon two-photon excitation in the NIR region.

Antitumoral gene-based strategy involving nitric oxide synthase type III overexpression in hepatocellular carcinoma

Hepatocellular carcinoma develops in cirrhotic liver. The nitric oxide (NO) synthase type III (NOS-3) overexpression induces cell death in hepatoblastoma cells. The study developed gene therapy designed to specifically overexpress NOS-3 in cultured hepatoma cells, and in tumors derived from orthotopically implanted tumor cells in fibrotic livers. Liver fibrosis was induced by CCl4 administration in mice. The first-generation adenoviruses were designed to overexpress NOS-3 or green fluorescent protein, and luciferase complementary DNA under the regulation of murine alpha-fetoprotein (AFP) and Rous Sarcoma Virus (RSV) promoters, respectively. Both adenovirus and Hepa 1-6 cells were used for in vitro and in vivo experiments. Adenoviruses were administered through the tail vein 2 weeks after orthotopic tumor cell implantation. AFP-NOS-3/RSV-luciferase increased oxidative-related DNA damage, p53, CD95/CD95L expression and caspase-8, -9 and -3 activities in cultured Hepa 1-6 cells. The increased expression of CD95/CD95L and caspase-8 activity was abolished by Nω-nitro-l-arginine methyl ester hydrochloride, p53 and CD95 small interfering RNA. AFP-NOS-3/RSV-luciferase adenovirus increased cell death markers, and reduced cell proliferation of established tumors in fibrotic livers. The increase of oxidative/nitrosative stress induced by NOS-3 overexpression induced DNA damage, p53, CD95/CD95L expression and cell death in hepatocellular carcinoma cells. The effectiveness of the gene therapy has been demonstrated in vitro and in vivo.

Comparative photo-release of nitric oxide from isomers of substituted terpyridinenitrosylruthenium(II) complexes: experimental and computational investigations

The 4'-(2-fluorenyl)-2,2':6',2''-terpyridine (FT) ligand and its cis(Cl,Cl)- and trans(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6) complexes have been synthesized. Both isomers were separated by HPLC and fully characterized by (1)H and (13)C NMR. The X-ray diffraction crystal structures were solved for FT (Pna21 space group, a = 34.960(4), b = 5.9306(7), c = 9.5911(10) Å), and trans(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6)·MeOH (P1[combining macron] space group, a = 10.3340(5), b = 13.0961(6), c = 13.2279(6) Å, α = 72.680(2), β = 70.488(2), γ = 67.090(2)°). Photo-release of NO˙ radicals occurs under irradiation at 405 nm, with a quantum yield of 0.31 and 0.10 for cis(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6) and trans(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6), respectively. This significant difference is likely due to the trans effect of Cl(-), which favors the photo-release. UV-visible spectroscopy and cyclic voltammetry indicate the formation of ruthenium(iii) species as photoproducts. A density functional theory (DFT) analysis provides a rationale for the understanding of the photo-physical properties, and allows relating the weakening of the Ru-NO bond, and finally the photo-dissociation, to HOMO → LUMO excitations.

Photocontrolled nitric oxide release from two nitrosylruthenium isomer complexes and their potential biomedical applications

Nitric oxide (NO) has key regulatory roles in various biological and medical processes. The control of its local concentration, which is crucial for obtaining the desired effect, can be achieved with exogenous NO donors. Release of NO from metal-nitrosyl complexes upon exposure to light is a strategy that could allow for the site-specific delivery of the reactive species NO to physiological targets. The photodissociation of NO from two nitrosylruthenium(II) isomer complexes {cis- and trans-[Ru(OAc)(2mqn)(2)NO]} was demonstrated by matrix-assisted laser desorption ionization time-of-flight mass spectrometry spectra, and electron paramagnetic resonance spectra further prove the photoinduced NO release by spin trapping of NO free radicals upon photoirradiation. Real-time NO release was quantitatively measured by electrochemistry with an NO-specific electrode. The quantitative control of NO release from [Ru(OAc)(2mqn)(2)NO] in aqueous solutions was done by photoirradiation at different wavelengths. Both isomers show photoinduced damage on plasmid DNA, but the trans isomer has higher cytotoxicity and photocytotoxicity activity against the HeLa tumor cell line than that of the cis isomer. Nitrosylruthenium(II) complex, with 8-quinolinol derivatives as ligands, has a great potential as a photoactivated NO donor reagent for biomedical applications.

Synthesis and biological evaluation of nitric oxide-releasing hybrids from gemcitabine and phenylsulfonyl furoxans as anti-tumor agents

Novel furoxan/gemcitabine hybrids displayed significant antitumor activities, in particular 10e, which could be independent of the nucleoside transporter, release high levels of NO, and induce cell apoptosis by regulating apoptotic related proteins in tumor cells in vitro.

Nitric oxide-releasing graft polymer micelles with distinct pendant amphiphiles

The architecture of nitric oxide-releasing graft polymer micelles affects the cargo release profile.

Site-directed delivery of nitric oxide to cancers

Nitric oxide (NO) is a reactive gaseous free radical which mediates numerous biological processes. At elevated levels, NO is found to be toxic to cancers and hence, a number of strategies for site-directed delivery of NO to cancers are in development during the past two decades. More recently, the focus of research has been to, in conjunction with other cancer drugs deliver NO to cancers for its secondary effects including inhibition of cellular drug efflux pumps. Among the various approaches toward site-selective delivery of exogenous NO sources, enzyme activated nitric oxide donors belonging to the diazeniumdiolate category afford unique advantages including exquisite control of rates of NO generation and selectivity of NO production. For this prodrug approach, enzymes including esterase, glutathione/glutathione S-transferase, DT-diaphorase, and nitroreductase are utilized. Here, we review the design and development of various approaches to enzymatic site-directed delivery of NO to cancers and their potential.

Low temperature plasma: a novel focal therapy for localized prostate cancer?

Despite considerable advances in recent years for the focal treatment of localized prostate cancer, high recurrence rates and detrimental side effects are still a cause for concern. In this review, we compare current focal therapies to a potentially novel approach for the treatment of early onset prostate cancer: low temperature plasma. The rapidly evolving plasma technology has the potential to deliver a wide range of promising medical applications via the delivery of plasma-induced reactive oxygen and nitrogen species. Studies assessing the effect of low temperature plasma on cell lines and xenografts have demonstrated DNA damage leading to apoptosis and reduction in cell viability. However, there have been no studies on prostate cancer, which is an obvious candidate for this novel therapy. We present here the potential of low temperature plasma as a focal therapy for prostate cancer.