JS-K, a GST-activated nitric oxide donor prodrug, enhances chemo-sensitivity in renal carcinoma cells and prevents cardiac myocytes toxicity induced by Doxorubicin

Generation and Accumulation of Various Advanced Glycation End-Products in Cardiomyocytes May Induce Cardiovascular Disease

Cardiomyocyte dysfunction and cardiovascular diseases (CVDs) can be classified as ischemic or non-ischemic. We consider the induction of cardiac tissue dysfunction by intracellular advanced glycation end-products (AGEs) in cardiomyocytes as a novel type of non-ischemic CVD. Various types of AGEs can be generated from saccharides (glucose and fructose) and their intermediate/non-enzymatic reaction byproducts. Recently, certain types of AGEs (Nε-carboxymethyl-lycine [CML], 2-ammnonio-6-[4-(hydroxymetyl)-3-oxidopyridinium-1-yl]-hexanoate-lysine [4-hydroxymethyl-OP-lysine, hydroxymethyl-OP-lysine], and Nδ-(5-hydro-5-methyl-4-imidazolone-2-yl)-ornithine [MG-H1]) were identified and quantified in the ryanodine receptor 2 (RyR2) and F-actin-tropomyosin filament in the cardiomyocytes of mice or patients with diabetes and/or heart failure. Under these conditions, the excessive leakage of Ca2+ from glycated RyR2 and reduced contractile force from glycated F-actin-tropomyosin filaments induce cardiomyocyte dysfunction. CVDs are included in lifestyle-related diseases (LSRDs), which ancient people recognized and prevented using traditional medicines (e.g., Kampo medicines). Various natural compounds, such as quercetin, curcumin, and epigallocatechin-3-gallate, in these drugs can inhibit the generation of intracellular AGEs through mechanisms such as the carbonyl trap effect and glyoxalase 1 activation, potentially preventing CVDs caused by intracellular AGEs, such as CML, hydroxymethyl-OP, and MG-H1. These investigations showed that bioactive herbal extracts obtained from traditional medicine treatments may contain compounds that prevent CVDs.

Nitric Oxide and Tumors: From Small-Molecule Donor to Combination Therapy

As an important endogenous signaling molecule, nitric oxide (NO) is involved in various physiological and pathological activities in living organisms. It is proved that NO plays a critical role in tumor therapy, while the extremely short half-life and nonspecific distribution of NO greatly limit its further clinical applications. Thus, the past few decades have witnessed the progress made in conquering these shortcomings, including developing innovative NO donors, especially smart and multimodal nanoplatforms. These platforms can precisely control the spatiotemporal distribution of therapeutic agents in the organism, which make big differences in tumor treatment. Here current NO therapeutic mechanisms for cancer, NO donors from small molecules to smart-responsive nanodrug delivery platforms, and NO-based combination therapy are comprehensively reviewed, emphasizing outstanding breakthroughs in these fields and hoping to bring new insights into NO-based tumor treatments.

Effects of combination docetaxel with NO treatment to enhance the anti-nasopharyngeal carcinoma efficiency in vitro and in vivo

Nasopharyngeal carcinoma (NPC) is one of the major causes of death in Southern China. Due to the insidious location of NPC, the therapeutic effect of locoregionally advanced NPC is still unsatisfactory. In this work, to improve the treatment efficiency, combining DOC and JS-K to inhibit NPC cells (HNE-1) in vitro was investigated, as well as its possible mechanisms. Moreover, the in vivo effects of DOC and JS-K combination treatment were also evaluated in a xenograft model with HNE-1 cells. In vitro experiments including cell proliferation, migration ability, apoptosis, and expression levels of apoptosis-associated proteins revealed that the combination of DOC and JS-K was able to enhance antitumor effects. In vivo results further confirmed a significant treatment effect without obvious toxicity on mice. The present work provides a promising idea for the treatment of locally advanced NPC.

Doxorubicin hydrochloride and L-arginine co-loaded nanovesicle for drug resistance reversal stimulated by near-infrared light

Drug resistance is accountable for the inadequate outcome of chemotherapy in clinics. The newly emerging role of nitric oxide (NO) to conquer drug resistance has been recognized as a potential strategy. However, it remains a great challenge to realize targeted delivery as well as accurate release of NO at desired sites. Herein, we developed a PEGylated indocyanine green (mPEG-ICG) integrated nanovesicle system (PIDA) to simultaneously load doxorubicin hydrochloride (DOX⋅HCl) and the NO donor L-arginine (L-Arg), which can produce NO triggered by NIR light irradiation and exert multimodal therapy to sensitize drug-resistant cancers. Upon 808 nm irradiation, the NO released from PIDA led to a decrease in mitochondrial membrane potential, an increase in ROS and significant ATP depletion in K562/ADR cells, thus inhibiting cell growth and resolving the problem of drug resistance. Consequently, the in vivo experiment on K562/ADR-bearing nude mice indicated that PIDA nanovesicles achieved significant anticancer efficacy with a tumor inhibition rate of 80.8%. Above all, PIDA nanovesicles offer guidance for designing nanoplatforms for drug-resistant cancer treatment.

Gasotransmitters in the tumor microenvironment: Impacts on cancer chemotherapy (Review)

Nitric oxide, carbon monoxide and hydrogen sulfide are three endogenous gasotransmitters that serve a role in regulating normal and pathological cellular activities. They can stimulate or inhibit cancer cell proliferation and invasion, as well as interfere with cancer cell responses to drug treatments. Understanding the molecular pathways governing the interactions between these gases and the tumor microenvironment can be utilized for the identification of a novel technique to disrupt cancer cell interactions and may contribute to the conception of effective and safe cancer therapy strategies. The present review discusses the effects of these gases in modulating the action of chemotherapies, as well as prospective pharmacological and therapeutic interfering approaches. A deeper knowledge of the mechanisms that underpin the cellular and pharmacological effects, as well as interactions, of each of the three gases could pave the way for therapeutic treatments and translational research.

O2-(2,4-dinitrophenyl) diazeniumdiolate derivative induces G2/M arrest via PTEN-mediated inhibition of PI3K/Akt pathway in hepatocellular carcinoma cells

OBJECTIVES

The study aimed to investigate whether G2/M arrest caused by O2-(2,4-dinitrophenyl) diazeniumdiolate derivative (JS-K) was related to PTEN-mediated inhibition of PI3K/Akt pathway in hepatocellular carcinoma cells.

METHODS

The cell apoptosis was detected by DAPI staining and Annexin V-FITC/PI dual staining. The cell cycle was analysed by PI staining. The expressions of cell cycle-related proteins, PTEN and PI3K/AKT pathway were measured by Western blot. The rat model of primary hepatic carcinoma was established with diethylnitrosamine to verify the antitumour effects of JS-K.

KEY FINDINGS

The morphological features of apoptosis were obviously reversed when the cells were pre-treated with bpv(pic), followed by treatment with JS-K. JS-K mediated G2/M arrest and down-regulated expressions of cyclin B1. Meanwhile, it up-regulated the expression of p-Cdk1, p-Chk2 and p-CDC25C while down-regulated that of Cdk1 and CDC25C. Furthermore, JS-K also enhanced the expressions of p21 and p27, PTEN and p53 while decreased the expressions of p-PTEN, PI3K and p-AKT. However, bpv(pic) and Carboxy-PTIO could reverse JS-K-induced G2/M cell arrest and PTEN-mediated inhibition of the PI3K/AKT pathway. The same results were also testified in the rat model of primary hepatic carcinoma.

CONCLUSIONS

JS-K caused G2/M arrest through PTEN-mediated inhibition of the PI3K/AKT pathway involving Chk2/CDC25C/Cdk1 checkpoint.

[Mn(PaPy2Q)(NO)]ClO4, a Near-Infrared Light activated release of Nitric Oxide drug as a nitric oxide donor for therapy of human prostate cancer cells in vitro and in vivo

This study was the first to investigate the synthesis of near-infrared light-sensitive NO prodrug [Mn(PaPy2Q)(NO)]ClO₄, and detection the amount of NO released by the drug in different time and near infrared light (10 mW, 20 mW). It showed that with the increase of light power, the time required for the drug to release NO was shortened, and we selected 20 mW, 10 min as a follow-up study of light power and irradiation time while ensuring the near-infrared light did not affect tumor cells. The cells were irradiated with 20 mW of near-infrared light for 10 min at 6 h after treatment with the drug on PC-3, LNCaP and 22RV1 cells, and NO concentration and cell survival rate were tested at 12 h, 24 h and 48 h. Experiments showed that NO concentration remained stable within 48 h and [Mn(PaPy2Q)(NO)]ClO₄ inhibited the proliferation of cells in a concentration and time-dependent manner. Then we also found that [Mn(PaPy2Q)(NO)]ClO₄ increased the expression of apoptosis-related proteins (PARP, Bax, Caspase 3/9), inhibited the expression of BCl-2 and increased the activity level of Caspase 3/7, which showed [Mn(PaPy2Q)(NO)]ClO₄ promoted prostate cancer cells apoptosis. Next, the results in xenograft mouse model showed that [Mn(PaPy2Q)(NO)]ClO₄ also had anti-prostate cancer effects in vivo, and the NO concentration increased in the tumor after near-infrared light irradiation. After [Mn(PaPy2Q)(NO)]ClO₄ treatment 6 weeks, tumor volume was significantly reduced, Ki67 and BrdU protein expression was significantly reduced. TUNEL assay results showed that [Mn(PaPy2Q)(NO)]ClO₄ could promote the apoptosis of solid tumors in vivo and in a concentration-dependent manner.

Metformin in combination with JS-K inhibits growth of renal cell carcinoma cells via reactive oxygen species activation and inducing DNA breaks

Metformin (MET) is taken as a principal medication for remedying Type 2 diabetes mellitus. Its anti-tumor effect has been reported increasingly, but the precise mechanism of it remains unclear. This study aims to explore the efficacy of MET and MET combined with nitric oxide donor prodrug JS-K on the proliferation, apoptosis, and DNA damage in human renal cell carcinoma (RCC) cells, and investigate the possible molecular mechanism involved. The cell proliferation was tested through methyl-tetrazolium assay and cell apoptosis was ascertained by flow cytometry. The dihydroethidium and JC-1 fluorescent methods were used to detect Reactive oxygen species (ROS) and mitochondrial transmembrane potential (Δψm), respectively. Proteins associated with apoptosis and DNA damage were evaluated by Western blotting. Results showed that MET and JS-K could suppress cell growth, and the inhibition concentration 50 of treatment with MET combined with JS-K (MET + JS-K) showed more toxicity than individual agents on RCC cells. This augmented toxicity was associated with intracellular reactive oxygen species (ROS) level, mitochondrial membrane potential alteration, and induced DNA breaks. The results of Western blotting showed that the expression level of pro-apoptotic proteins, such as Bax, Bak, caspase-3, and caspase-9, was up-regulated, and the anti-apoptotic protein Bcl-2 was down-regulated after treatment using MET alone and MET + JS-K, correspondingly. Moreover, MET + JS-K inhibited the expression of cellular PCNA and Rad51, and immunofluorescence analysis of γH2AX proved that MET + JS-K enhanced DNA damage. In summary, the results of this research indicated that MET and JS-K inhibited RCC cell growth by activating ROS, targeting mitochondria-dependent apoptotic pathways, and inducing DNA breaks.

Sensitizing activities of nitric oxide donors for cancer resistance to anticancer therapeutic drugs

Cancer is not a single disease but it constitutes a large variety of different types that are also different from each other phenotypically and molecularly. Although the standard treatments have resulted in clinical responses in a subset of patients, though, many patients relapse and no longer respond to further treatments. Hence, both the innate and adaptive resistance to treatments are the main challenges in today's treatment strategies. Noteworthy, several novel treatment strategies, particularly immunotherapies, used alone or in combination, have been developed and that have significantly improved the therapeutic response of many unresponsive cancer patients. Nevertheless, even with the latest new developments of therapeutics that were effective in a larger subset of patients, there is still an urgent need to treat the remaining unresponsive subset of patients. This requires the development of new targeting agents of superior antitumor activities that will lead to overcoming the unaffected resistance by current treatments. There has been accumulating evidence suggesting nitric oxide donors as such targeting agents and considering their pleiotropic antitumor activities, including both the reversal of chemo and immuno-resistance of various unresponsive resistant cancers. The in vitro and in vivo preclinical findings corroborate the sensitizing antitumor activities of nitric oxide donors. In addition, a few clinical findings with NO donors that have been applied in patients have corroborated their antitumor and sensitizing activities in combination with standard therapies. In this review, the role and underlying mechanisms by which nitric oxide donors sensitize cancer resistant cells to both chemotherapy and immunotherapy are briefly described.

Gaseous signaling molecules and their application in resistant cancer treatment: from invisible to visible

Multidrug resistance (MDR) in cancer remains a critical obstacle for efficient chemotherapy. Many MDR reversal agents have been discovered but failed in clinical trials due to severe toxic effects. Gaseous signaling molecules (GSMs), such as oxygen, nitric oxide, hydrogen sulfide and carbon monoxide, play key roles in regulating cell biological function and MDR. Compared with other toxic chemosensitizing agents, GSMs are endogenous and biocompatible molecules with little side effects. Research show that GSM modulators, including pharmaceutical formulations of GSMs (combined with conventional chemotherapeutic drugs) and GSM-donors (small molecules with GSMs releasing property), can overcome or reverse MDR. This review discusses the roles of these four GSMs in modulating MDR, and summarizes GSMs modulators in treating cancers with drug resistance.

JS-K enhances chemosensitivity of prostate cancer cells to Taxol via reactive oxygen species activation

The aim of the present study was to investigate the influence of the nitric oxide donor prodrug JS-K (C₁₃H₁₆N₆O₈) on Taxol-induced apoptosis in prostate cancer cells, and to investigate a potential reactive oxygen species (ROS)-associated mechanism. The effect of JS-K on the anticancer activity of Taxol was assessed in prostate cancer cells; cell viability, colony formation, apoptosis, ROS generation and expression levels of apoptosis-associated proteins were investigated. The function of ROS accumulation in the combined effects of JS-K and Taxol was determined using the antioxidant N-acetylcysteine (NAC) and the pro-oxidant oxidized glutathione (GSSG). The results of the present study demonstrated that JS-K was able to increase Taxol-induced suppression of prostate cancer cell proliferation, apoptosis, ROS accumulation and upregulation of apoptosis-associated proteins. Furthermore, NAC reversed the effect of JS-K on Taxol-induced apoptosis and conversely, the pro-oxidant GSSG exacerbated the effect of JS-K on Taxol-induced apoptosis in prostate cancer cells. In conclusion, JS-K enhances the chemosensitivity of prostate cancer cells to Taxol, via the upregulation of intracellular ROS.

Glutathione S-transferase π: a potential role in antitumor therapy

Glutathione S-transferase π (GSTπ) is a Phase II metabolic enzyme that is an important facilitator of cellular detoxification. Traditional dogma asserts that GSTπ functions to catalyze glutathione (GSH)-substrate conjunction to preserve the macromolecule upon exposure to oxidative stress, thus defending cells against various toxic compounds. Over the past 20 years, abnormal GSTπ expression has been linked to the occurrence of tumor resistance to chemotherapy drugs, demonstrating that this enzyme possesses functions beyond metabolism. This revelation reveals exciting possibilities in the realm of drug discovery, as GSTπ inhibitors and its prodrugs offer a feasible strategy in designing anticancer drugs with the primary purpose of reversing tumor resistance. In connection with the authors' current research, we provide a review on the biological function of GSTπ and current developments in GSTπ-targeting drugs, as well as the prospects of future strategies.

Protein phosphatase 2A activation mechanism contributes to JS-K induced caspase-dependent apoptosis in human hepatocellular carcinoma cells

Background

JS-K is a nitric oxide (NO) donor and could generate intracellularly high levels of NO. The study explores PP2A as a tumor suppressor is a major determinant mediating JS-K-caused apoptosis in human hepatocellular carcinoma (HCC) cells.

Methods

The human HCC cell lines (PLC5, Huh-7, Bel-7402, SMMC-7721 and HepG2) were used to assess effects of JS-K on cell viability, apoptosis induction and PP2A activation. Effects of JS-K on cell morphology, mitochondrial membrane potential, apoptosis and NO levels were determined in HCC cells expressing PP2A. Simultaneously, the expression of PP2A family including PP2A-A(α/β), PP2A-B55, PP2A-C(α/β) and the substrates of PP2A, such as β-catenin, c-Myc and p-Bcl-2 (Ser70) were detected in sensitive HCC cells. Furthermore, the role of NO in mediating the expression of PP2A was further validated with Z-VAD-FMK (a caspase inhibitor), Carboxy-PTIO (a NO scavenger), okadaic acid (OA, a PP2A inhibitor) and FTY720 (a PP2A agonist) in JS-K treated cells. In addition, the genetic manuplation of PP2A including overexpression and knockdown have been also performed in JS-K treated cells. Moreover, the rat model of primary hepatic carcinoma was established with diethylnitrosamine for 16 weeks to verify the anti-tumor effects of JS-K in vivo. Immunohistochemical and Western blot analysis were used to determine the expression of proteins in rat primary hepatic carcinoma tissues.

Results

JS-K significantly inhibited cell proliferation, increased apoptosis rate and activated PP2A activity in five HCC cells viability, especially SMMC7721 and HepG2 cells. It was characterized by loss of mitochondrial membrane potential, significant externalization of phosphatidylserine, nuclear morphological changes. Moreover, JS-K enhanced Bax-to-Bcl-2 ratio, released cytochrome c (Cyt c) from mitochondria, activated cleaved-caspase-9/3 and the cleavage of PARP, and decreased the expression of X-linked inhibitor of apoptosis protein (XIAP). Both Z-VAD-FMK and Carboxy-PTIO suppressed the activation of cleaved-caspase-9/3 and of cleaved-PARP in JS-K-treated sensitive HCC cells. Simultaneously, JS-K treatment could lead to the activation of protein phosphatase 2A-C (PP2A-C) but not PP2A-A and PP2A-B55, which subsequently inactivated and dephosphorylated the PP2A substrates including β-catenin, c-Myc, and p-Bcl-2 (Ser70). However, silencing PP2A-C could abolish both the activation of PP2A-C and down-regulation of β-catenin, c-Myc and p-Bcl-2 (Ser70) in sensitive HCC cells. Conversely, PP2A overexpression could enhance the effects of JS-K on activation of PP2A and down-regulation of β-catenin, c-Myc and p-Bcl-2 (Ser70). In addition, adding okadaic acid (OA), a PP2A inhibitor, abolished the effects of JS-K on apoptosis induction, PP2A activation and the substrates of PP2A dephosphorylation; FTY720, a PP2A agonist, enhanced the effects of JS-K including apoptosis induction, PP2A activation and the substrates of PP2A dephosphorylation. The mice exhibited a lower number and smaller tumor nodules in response to JS-K-treated group. A marked increase in the number of hepatocytes with PCNA-positive nuclei (proliferating cells) was evident in DEN group and tended to decrease with JS-K treatment. Furthermore, JS-K treatment could induce PP2A activation and the substrates of PP2A inactivation such as β-catenin, c-Myc and p-Bcl-2(Ser70) in DEN-induced hepatocarcinogenesis.

Conclusions

High levels of NO released from JS-K induces a caspase-dependent apoptosis through PP2A activation.

Effect of resveratrol on doxorubicin resistance in breast neoplasm cells by modulating PI3K/Akt signaling pathway

In the study, we probed into the effect of Resveratrol (RES) on Doxorubicin (DOX)-resistant breast neoplasm cell line MCF-7/DOX as well as the mechanism of RES underlying the DOX-resistant breast cancer. CCK-8 assay was utilized to assess the survival rates and sensitivity of breast neoplasm cell lines MCF-7 or MDA-MB-231 to DOX and RES. DOX-resistant MCF-7 cell line was successfully cultivated with DOX dose increasing and was named MCF-7/DOX. Afterwards, wound healing and Transwell assays were performed to measure the migration and invasion capabilities of MCF-7/DOX cells, while cell propagation and apoptosis were determined by colony formation assay and flow cytometry analysis. Both western blotting and immunohistochemistry were conducted to examine the expression of proteins involved in PI3K/Akt signaling pathway. Nude mice xenograft model was constructed to further verify the effects of DOX and RES on breast neoplasm in vivo. RES restored DOX sensitivity in MCF-7/DOX cells, inhibiting biological functions of MCF-7/DOX cells and promoting cell apoptosis in vitro and impeding tumor growth in vivo. It was revealed by the mechanistic studies that MCF-7/DOX cells could regain the drug sensibility with RES treatment through inactivating the PI3K/Akt signal transduction pathway. RES could reverse DOX resistance in breast neoplasm cells and inhibited DOX-resistant breast cancer cell propagation and metastasis and facilitated cell apoptosis by modulating PI3K/Akt signaling pathway. © 2018 IUBMB Life, 70(6):491-500, 2018.