Role of Glutathione in Cancer: From Mechanisms to Therapies

Metabolic Rewiring Is Essential for AML Cell Survival to Overcome Autophagy Inhibition by Loss of ATG3

Autophagy is an important survival mechanism that allows recycling of nutrients and removal of damaged organelles and has been shown to contribute to the proliferation of acute myeloid leukemia (AML) cells. However, little is known about the mechanism by which autophagy- dependent AML cells can overcome dysfunctional autophagy. In our study we identified autophagy related protein 3 (ATG3) as a crucial autophagy gene for AML cell proliferation by conducting a CRISPR/Cas9 dropout screen with a library targeting around 200 autophagy-related genes. shRNA-mediated loss of ATG3 impaired autophagy function in AML cells and increased their mitochondrial activity and energy metabolism, as shown by elevated mitochondrial ROS generation and mitochondrial respiration. Using tracer-based NMR metabolomics analysis we further demonstrate that the loss of ATG3 resulted in an upregulation of glycolysis, lactate production, and oxidative phosphorylation. Additionally, loss of ATG3 strongly sensitized AML cells to the inhibition of mitochondrial metabolism. These findings highlight the metabolic vulnerabilities that AML cells acquire from autophagy inhibition and support further exploration of combination therapies targeting autophagy and mitochondrial metabolism in AML.

Effects of the Combined Treatment with a G-Quadruplex-Stabilizing Ligand and Photon Beams on Glioblastoma Stem-like Cells: A Magnetic Resonance Study

Glioblastoma multiforme is a malignant primary brain tumor with a poor prognosis and high rates of chemo-radiotherapy failure, mainly due to a small cell fraction with stem-like properties (GSCs). The mechanisms underlying GSC response to radiation need to be elucidated to enhance sensitivity to treatments and to develop new therapeutic strategies. In a previous study, two GSC lines, named line #1 and line #83, responded differently to carbon ions and photon beams, with the differences likely attributable to their own different metabolic fingerprint rather than to radiation type. Data from the literature showed the capability of RHPS4, a G-quadruplex stabilizing ligand, to sensitize the glioblastoma radioresistant U251MG cells to X-rays. The combined metabolic effect of ligand #190, a new RHPS4-derivative showing reduced cardiotoxicity, and a photon beam has been monitored by magnetic resonance (MR) spectroscopy for the two GSC lines, #1 and #83, to reveal whether a synergistic response occurs. MR spectra from both lines were affected by single and combined treatments, but the variations of the analysed metabolites were statistically significant mainly in line #1, without synergistic effects due to combination. The multivariate analysis of ten metabolites shows a separation between control and treated samples in line #1 regardless of treatment type, while separation was not detected in line #83.

Multiple Infusion Start Time Mass Spectrometry Imaging of Dynamic SIL-Glutathione Biosynthesis Using Infrared Matrix-Assisted Laser Desorption Electrospray Ionization

Due to the high association of glutathione metabolism perturbation with a variety of disease states, there is a dire need for analytical techniques to study glutathione kinetics. Additionally, the elucidation of microenvironmental effects on changes in glutathione metabolism would significantly improve our understanding of the role of glutathione in disease. We therefore present a study combining a multiple infusion start time protocol, stable isotope labeling technology, infrared matrix-assisted laser desorption electrospray ionization, and high-resolution accurate mass-mass spectrometry imaging to study spatial changes in glutathione kinetics across in sectioned mouse liver tissues. After injecting a mouse with the isotopologues [2-¹³C,¹⁵N]-glycine, [1,2-¹³C₂]-glycine, and [1,2-¹³C₂,¹⁵N]-glycine at three different time points, we were able to fully resolve and spatially map their metabolism into three isotopologues of glutathione and calculate their isotopic enrichment in glutathione. We created a tool in the open-source mass spectrometry imaging software MSiReader to accurately compute the percent isotope enrichment (PIE) of these labels in glutathione and visualize them in heat-maps of the tissue sections. In areas of high flux, we found that each label enriched an approximate median of 1.6%, 1.8%, and 1.5%, respectively, of the glutathione product pool measured in each voxel. This method may be adapted to study the heterogeneity of glutathione flux in diseased versus healthy tissues.

Molecular mechanisms underlying the effect of diacerein on trichloroacetic acid-induced hepatic pre-neoplastic lesions in rats

CONCLUSION

IL-1β mediates angiogenesis indirectly, as it has been shown to induce hypoxia-inducible factor-1α (HIF-1α) which upregulates VEGF.

The Prognostic Role of Glutathione and Its Related Antioxidant Enzymes in the Recurrence of Hepatocellular Carcinoma

The imbalance of high oxidative stress and low antioxidant capacities is thought to be a significant cause of the development and progression of hepatocellular carcinoma (HCC). However, the impact of oxidative stress, glutathione (GSH), and its related antioxidant enzymes on the recurrence of HCC has not been investigated. The purpose of this study was to compare the changes to oxidative stress and GSH-related antioxidant capacities before and after tumor resection in patients with HCC recurrence and non-recurrence. We also evaluated the prognostic significance of GSH and its related enzymes in HCC recurrence. This was a cross-sectional and follow-up study. Ninety-two HCC patients who were going to receive tumor resection were recruited. We followed patients' recurrence and survival status until the end of the study, and then assigned patients into the recurrent or the non-recurrent group. The tumor recurrence rate was 52.2% during the median follow-up period of 3.0 years. Patients had significantly lower plasma malondialdehyde level, but significantly or slightly higher levels of GSH, glutathione disulfide, trolox equivalent antioxidant capacity, glutathione peroxidase (GPx), and glutathione reductase (GR) activities after tumor resection compared to the respective levels before tumor resection in both recurrent and non-recurrent groups. GSH level in HCC tissue was significantly higher than that in adjacent normal tissue in both recurrent and non-recurrent patients. Decreased plasma GPx (HR = 0.995, p = 0.01) and GR (HR = 0.98, p = 0.04) activities before tumor resection, and the increased change of GPx (post-pre-resection) (HR = 1.004, p = 0.03) activity were significantly associated with the recurrence of HCC. These findings suggest there might be a possible application of GPx or GR as therapeutic targets for reducing HCC recurrence.

Lipid Catabolism and ROS in Cancer: A Bidirectional Liaison

Although cancer cell metabolism was mainly considered to rely on glycolysis, with the concomitant impairment of mitochondrial metabolism, it has recently been demonstrated that several tumor types are sustained by oxidative phosphorylation (OXPHOS). In this context, endogenous fatty acids (FAs) deriving from lipolysis or lipophagy are oxidised into the mitochondrion, and are used as a source of energy through OXPHOS. Because the electron transport chain is the main source of ROS, cancer cells relying on fatty acid oxidation (FAO) need to be equipped with antioxidant systems that maintain the ROS levels under the death threshold. In those conditions, ROS can act as second messengers, favouring proliferation and survival. Herein, we highlight the different responses that tumor cells adopt when lipid catabolism is augmented, taking into account the different ROS fates. Many papers have demonstrated that the pro- or anti-tumoral roles of endogenous FA usage are hugely dependent on the tumor type, and on the capacity of cancer cells to maintain redox homeostasis. In light of this, clinical studies have taken advantage of the boosting of lipid catabolism to increase the efficacy of tumor therapy, whereas, in other contexts, antioxidant compounds are useful to reduce the pro-survival effects of ROS deriving from FAO.

Profiling the Concentration of Reduced and Oxidized Glutathione in Rat Brain Using HPLC/DAD Chromatographic System

This study aimed to develop a HPLC/DAD method in order to determine and quantify the reduced glutathione (GSH) and oxidized glutathione (GSSG) levels in rat brain. Due to the presence of the thiol group (-SH), GSH can interact with the Ellman′s reagent (DTNB), with which it forms a reaction product through which the level of GSH can be quantified, using the DAD detection system. Chromatographic separation was achieved after a derivatization process by using a mobile phase acetonitrile (A) and phosphate buffer (20 mM, pH = 2.5) (B). The compounds of interest were detected at 330 nm using a chromatographic C8 column. The method of determination met the validation criteria, specified by the regulatory bodies. The applicability of the method was demonstrated in a chronic toxicology study of central nervous system (CNS), following different treatment regimens with haloperidol.

Riluzole: A neuroprotective drug with potential as a novel anti‑cancer agent (Review)

Riluzole, a glutamate release inhibitor, has been in use for the treatment of amyotrophic lateral sclerosis for over two decades since its approval by the Food and Drug Administration. Recently, riluzole has been evaluated in cancer cells and indicated to block cell proliferation and/or induce cell death. Riluzole has been proven effective as an anti-neoplastic drug in cancers of various tissue origins, including the skin, breast, pancreas, colon, liver, bone, brain, lung and nasopharynx. While cancer cells expressing glutamate receptors frequently respond to riluzole treatment, numerous types of cancer cell lacking glutamate receptors unexpectedly responded to riluzole treatment as well. Riluzole was demonstrated to interfere with glutamate secretion, growth signaling pathways, Ca²⁺ homeostasis, glutathione synthesis, reactive oxygen species generation and integrity of DNA, as well as autophagic and apoptotic pathways. Of note, riluzole is highly effective in inducing cell death in cisplatin-resistant lung cancer cells. Furthermore, riluzole pretreatment sensitizes glioma and melanoma to radiation therapy. In addition, in triple-negative breast cancer, colorectal cancer, melanoma and glioblastoma, riluzole has synergistic effects in combination with select drugs. In an effort to highlight the therapeutic potential of riluzole, the current study reviewed the effect and outcome of riluzole treatment on numerous cancer types investigated thus far. The mechanism of action and the various molecular pathways affected by riluzole are discussed.

Resveratrol and cyclodextrins, an easy alliance: Applications in nanomedicine, green chemistry and biotechnology

Most drugs or the natural substances reputed to display some biological activity are hydrophobic molecules that demonstrate low bioavailability regardless of their mode of absorption. Resveratrol and its derivatives belong to the chemical group of stilbenes; while stilbenes are known to possess very interesting properties, these are limited by their poor aqueous solubility as well as low bioavailability in animals and humans. Among the substances capable of forming nanomolecular inclusion complexes which can be used for drug delivery, cyclodextrins show spectacular physicochemical and biomedical implications in stilbene chemistry for their possible application in nanomedicine. By virtue of their properties, cyclodextrins have also demonstrated their possible use in green chemistry for the synthesis of stilbene glucosylated derivatives with potential applications in dermatology and cosmetics. Compared to chemical synthesis and genetically modified microorganisms, plant cell or tissue systems provide excellent models for obtaining stilbenes in few g/L quantities, making feasible the production of these compounds at a large scale. However, the biosynthesis of stilbenes is only possible in the presence of the so-called elicitor compounds, the most commonly used of which are cyclodextrins. We also report here on the induction of resveratrol production by cyclodextrins or combinatory elicitation with methyljasmonate in plant cell systems as well as the mechanisms by which they are able to trigger a stilbene response. The present article therefore discusses the role of cyclodextrins in stilbene chemistry both at the physico-chemical level as well as the biomedical and biotechnological levels, emphasizing the notion of "easy alliance" between these compounds and stilbenes.

Thiol-Responsive Gold Nanodot Swarm with Glycol Chitosan for Photothermal Cancer Therapy

Photothermal therapy (PTT) is one of the most promising cancer treatment methods because hyperthermal effects and immunogenic cell death via PTT are destructive to cancer. However, PTT requires photoabsorbers that absorb near-infrared (NIR) light with deeper penetration depth in the body and effectively convert light into heat. Gold nanoparticles have various unique properties which are suitable for photoabsorbers, e.g., controllable optical properties and easy surface modification. We developed gold nanodot swarms (AuNSw) by creating small gold nanoparticles (sGNPs) in the presence of hydrophobically-modified glycol chitosan. The sGNPs assembled with each other through their interaction with amine groups of glycol chitosan. AuNSw absorbed 808-nm laser and increased temperature to 55 °C. In contrast, AuNSw lost its particle structure upon exposure to thiolated molecules and did not convert NIR light into heat. In vitro studies demonstrated the photothermal effect and immunogenic cell death after PTT with AuNSW. After intratumoral injection of AuNSw with laser irradiation, tumor growth of xenograft mouse models was depressed. We found hyperthermal damage and immunogenic cell death in tumor tissues through histological and biochemical analyses. Thiol-responsive AuNSw showed feasibility for PTT, with advanced functionality in the tumor microenvironment.

Nanoencapsulation of thyme essential oil: a new avenue to enhance its protective role against oxidative stress and cytotoxicity of zinc oxide nanoparticles in rats

Although the green synthesis of nanometals is eco-friendly, the toxicity or safety of these biosynthesized nanoparticles in living organisms is not fully studied. This study aimed to evaluate the potential protective role of encapsulated thyme oil (ETO) against zinc oxide nanoparticles (ZnO-NPs). ETO was prepared using a mixture of whey protein isolate, maltodextrin, and gum Arabic, and ZnO-NPs were synthesized using parsley extract. Six groups of male Sprague-Dawley rats were treated orally for 21 days which included the control group, ZnO-NP-treated group (25 mg/kg body weight (b.w.)), ETO-treated groups at low or high dose (50, 100 mg/kg b.w.), and the groups that received ZnO-NPs plus ETO at the two tested doses. Blood and tissue samples were collected for different assays. The results showed that carvacrol and thymol were the major components in ETO among 13 compounds isolated by GC-MS. ZnO-NPs were nearly spherical and ETOs were round in shape with an average size of 38 and 311.8 nm, respectively. Administration of ZnO-NPs induced oxidative stress, DNA damage, biochemical, ctyogentical, and histological changes in rats. ETO at the tested doses alleviated these disturbances and showed protective effects against the hazards of ZnO-NPs. It could be concluded that encapsulation of thyme oil using whey protein isolate, maltodextrin, and gum Arabic improved the antioxidant properties of ETO, probably possess synergistic effects, and can be used as a promising tool in pharmaceutical and food applications.

Development and validation of a ferroptosis-related lncRNAs prognosis signature in colon cancer

Ferroptosis is a form of iron-dependent programmed cell death. Regulation of ferroptosis in tumor cells is a novel treatment modality. The present study aimed to investigate ferroptosis-related long non-coding RNAs (lncRNAs) and construct a prognostic model for colon adenocarcinoma (COAD). RNA- sequencing data and ferroptosis-related genes were obtained from The Cancer Genome Atlas database and FerrDb database. COAD patients were randomly assigned to training- and validation groups. The Least Absolute Shrinkage and Selection Operator regression and Cox regression model were used to determine and develop a predictive model. The model was corroborated using the validation group and the entire group. In total, 259 ferroptosis-related genes and 905 ferroptosis-related LncRNAs were obtained. Cox model revealed and constructed seven ferroptosis-related LncRNAs signature (LINC01503, AC004687.1, AC010973.2, AP001189.3, ARRDC1-AS1, OIP5-AS1, and NCK1-DT). Patients were assigned into two groups according to the median risk score. Kaplan-Meier survival curves showed that overall survival between high- and low-risk groups was statistically significant (P<0.01). Cox multivariate analysis seven ferroptosis-related LncRNAs signature was an independent risk factor for COAD outcomes (P<0.05). The relationship between seven ferroptosis-related LncRNAs and clinicopathological features was also examined. The principal component analysis showed a difference between high- and low-risk groups intuitively. With the aid of gene set enrichment analysis, the underlying mechanisms of seven ferroptosis-related LncRNAs were uncovered, including the MAPK signaling pathway, mTOR signaling pathway, and glutathione metabolism pathway. Finally, we established and validated seven ferroptosis-related lncRNAs signature for COAD patients to predict survival. These results may provide meaningful targets for future study.

Pharmacological Properties of 2,4,6-Trihydroxy-3-Geranyl Acetophenone and the Underlying Signaling Pathways: Progress and Prospects

2,4,6-Trihydroxy-3-geranyl acetophenone (tHGA) is a bioactive phloroglucinol compound found in Melicope pteleifolia (Champ. ex Benth.) T.G.Hartley, a medicinal plant vernacularly known as “tenggek burung”. A variety of phytochemicals have been isolated from different parts of the plant including leaves, stems, and roots by using several extraction methods. Specifically, tHGA, a drug-like compound containing phloroglucinol structural core with acyl and geranyl group, has been identified in the methanolic extract of the young leaves. Due to its high nutritional and medicinal values, tHGA has been extensively studied by using various experimental models. These studies have successfully discovered various interesting pharmacological activities of tHGA such as anti-inflammatory, endothelial and epithelial barrier protective, anti-asthmatic, anti-allergic, and anti-cancer. More in-depth investigations later found that these activities were attributable to the modulatory actions exerted by tHGA on specific molecular targets. Despite these findings, the association between the mechanisms and signaling pathways underlying each pharmacological activity remains largely unknown. Also, little is known about the medicinal potentials of tHGA as a drug lead in the current pharmaceutical industry. Therefore, this mini review aims to summarize and relate the pharmacological activities of tHGA in terms of their respective mechanisms of action and signaling pathways in order to present a perspective into the overall modulatory actions exerted by tHGA. Besides that, this mini review will also pinpoint the unexplored potentials of this compound and provide some valuable insights into the potential applications of tHGA which may serve as a guide for the development of modern medication in the future.

Not Only a Weed Plant-Biological Activities of Essential Oil and Hydrosol of Dittrichia viscosa (L.) Greuter

With the increasing interest in obtaining biologically active compounds from natural sources, Dittrichia viscosa (L.) Greuter (Asteraceae) came into our focus as a readily available and aromatic wild shrub widely distributed in the Mediterranean region. This work provides a phytochemical profile of D. viscosa in terms of parallel chemical composition in the lipophilic fraction (essential oil) and the water fraction (hydrosol). GC-MS analysis identified 1,8-cineole, caryophyllene oxide, α-terpenyl acetate, and α-muurolol as the major components of the essential oil, while in the hydrosol p-menth-1-en-9-ol, 1,8-cineole, linalool, cis-sabinene hydrate, and α-muurolol were the major volatile components. 3,4-Dihydroxybenzoic acid was found to be the predominant compound in the hydrosol composition by HPLC analysis. The antimicrobial potential of both extracts was evaluated against thirteen opportunistic pathogens associated with common skin and wound infections and emerging food spoilage microorganisms. The antimicrobial activity of the essential oil suggests that the volatiles of D. viscosa could be used as novel antimicrobial agents. The antiproliferative results of D. viscosa volatiles are also new findings, which showed promising activity against three cancer cell lines: HeLa (cervical cancer cell line), HCT116 (human colon cancer cell line), and U2OS (human osteosarcoma cell line). The decrease in GSH level observed in hydrosol-treated HeLa cells suggests oxidative stress as a possible mechanism of the antiproliferative effect of hydrosol on tumor cells. The presented results are also the first report of significant antiphytoviral activity of hydrosol against tobacco mosaic virus (TMV) infection. Based on the results, D. viscosa might have the potential to be used in crop protection, as a natural disinfectant and natural anticancer agent.

Omega-3 Fatty Acids DHA and EPA Reduce Bortezomib Resistance in Multiple Myeloma Cells by Promoting Glutathione Degradation

Multiple myeloma (MM) is a hematological malignancy that exhibits aberrantly high levels of proteasome activity. While treatment with the proteasome inhibitor bortezomib substantially increases overall survival of MM patients, acquired drug resistance remains the main challenge for MM treatment. Using a combination treatment of docosahexaenoic acid (DHA) or eicosapentaenoic acid (EPA) and bortezomib, it was demonstrated previously that pretreatment with DHA/EPA significantly increased bortezomib chemosensitivity in MM cells. In the current study, both transcriptome and metabolome analysis were performed to comprehensively evaluate the underlying mechanism. It was demonstrated that pretreating MM cells with DHA/EPA before bortezomib potently decreased the cellular glutathione (GSH) level and altered the expression of the related metabolites and key enzymes in GSH metabolism, whereas simultaneous treatment only showed minor effects on these factors, thereby suggesting the critical role of GSH degradation in overcoming bortezomib resistance in MM cells. Moreover, RNA-seq results revealed that the nuclear factor erythroid 2-related factor 2 (NRF2)-activating transcription factor 3/4 (ATF3/4)-ChaC glutathione specific gamma-glutamylcyclotransferase 1 (CHAC1) signaling pathway may be implicated as the central player in the GSH degradation. Pathways of necroptosis, ferroptosis, p53, NRF2, ATF4, WNT, MAPK, NF-κB, EGFR, and ERK may be connected to the tumor suppressive effect caused by pretreatment of DHA/EPA prior to bortezomib. Collectively, this work implicates GSH degradation as a potential therapeutic target in MM and provides novel mechanistic insights into its significant role in combating bortezomib resistance.

The Link between Type 2 Diabetes Mellitus and the Polymorphisms of Glutathione-Metabolizing Genes Suggests a New Hypothesis Explaining Disease Initiation and Progression

The present study investigated whether type 2 diabetes (T2D) is associated with polymorphisms of genes encoding glutathione-metabolizing enzymes such as glutathione synthetase (GSS) and gamma-glutamyl transferase 7 (GGT7). A total of 3198 unrelated Russian subjects including 1572 T2D patients and 1626 healthy subjects were enrolled. Single nucleotide polymorphisms (SNPs) of the GSS and GGT7 genes were genotyped using the MassArray-4 system. We found that the GSS and GGT7 gene polymorphisms alone and in combinations are associated with T2D risk regardless of sex, age, and body mass index, as well as correlated with plasma glutathione, hydrogen peroxide, and fasting blood glucose levels. Polymorphisms of GSS (rs13041792) and GGT7 (rs6119534 and rs11546155) genes were associated with the tissue-specific expression of genes involved in unfolded protein response and the regulation of proteostasis. Transcriptome-wide association analysis has shown that the pancreatic expression of some of these genes such as EDEM2, MYH7B, MAP1LC3A, and CPNE1 is linked to the genetic risk of T2D. A comprehensive analysis of the data allowed proposing a new hypothesis for the etiology of type 2 diabetes that endogenous glutathione deficiency might be a key condition responsible for the impaired folding of proinsulin which triggered an unfolded protein response, ultimately leading to beta-cell apoptosis and disease development.

Redox-Responsive Mesoporous Silica Nanoparticles for Cancer Treatment: Recent Updates

Mesoporous silica nanoparticles have been widely applied as carriers for cancer treatment. Among the different types of stimuli-responsive drug delivery systems, those sensitive to redox stimuli have attracted much attention. Their relevance arises from the high concentration of reductive species that are found within the cells, compared to bloodstream, which leads to the drug release taking place only inside cells. This review is intended to provide a comprehensive overview of the most recent trends in the design of redox-responsive mesoporous silica nanoparticles. First, a general description of the biological rationale of this stimulus is presented. Then, the different types of gatekeepers that are able to open the pore entrances only upon application of reductive conditions will be introduced. In this sense, we will distinguish among those targeted and those non-targeted toward cancer cells. Finally, a new family of bridged silica nanoparticles able to degrade their structure upon application of this type of stimulus will be presented.

Integrative analyses of gene expression and chemosensitivity of patient-derived ovarian cancer spheroids link G6PD-driven redox metabolism to cisplatin chemoresistance

Patient-derived cells and xenografts retain the biological characteristics of clinical cancers and are instrumental in gaining a better understanding of the chemoresistance of cancer cells. Here, we have established a panel of patient-derived spheroids from clinical materials of ovarian cancer. Systematic evaluation using therapeutic agents indicated that sensitivity to platinum-based compounds significantly varied among the spheroids. To understand the molecular basis of drug sensitivity, we performed integrative analyses combining chemoresistance data and gene expression profiling of the ovarian cancer patient-derived spheroids. Correlation analyses revealed that cisplatin resistance was significantly associated with elevated levels of glucose-6-phosphate dehydrogenase (G6PD) and glutathione-producing redox enzymes. Accordingly, cisplatin-resistant spheroids established in vitro showed elevated levels of G6PD and active glutathione. Moreover, treatment with a G6PD inhibitor in combination with cisplatin suppressed spheroid proliferation in vitro and largely eradicated peritoneal metastasis in mouse xenograft models. Furthermore, G6PD expression was elevated during carcinogenesis and associated with poor prognosis. Thus, the combination of gene expression data and chemosensitivity revealed the essential roles of G6PD-driven redox metabolism in cisplatin resistance, underscoring the significance of an integrative approach using patient-derived cells.

Smart Modification on Magnetic Nanoparticles Dramatically Enhances Their Therapeutic Properties

Simple Summary

In this work, a smart gemcitabine delivery system based on magnetic nanoparticles (MNP) is proposed. Gemcitabine (GEM) is a chemotherapeutic agent usually employed as monotherapy for the treatment of pancreatic cancer. Unfortunately, this drug presents short half-life and high toxicity in non-tumoral tissues. Thus, new efficient drug delivery systems are needed. In this regard, we modified MNP to attach this drug via disulfide bonds (MNP-GEM) to promote the selective release of GEM in pancreatic cancer cells, and the great potential of our proposed nanocarrier for biomedical applications is broadly assessed. Remarkably, this modification has proved to prevent the unspecific binding of proteins, reduced the cytotoxic effect of the drug in non-cancerous cells, improved the internalization in pancreatic cancer cells, and its activity was synergistically enhanced in combination with magnetic hyperthermia.

Abstract

Magnetic nanoparticles (MNP) are employed as nanocarriers and in magnetic hyperthermia (MH) for the treatment of cancers. Herein, a smart drug delivery system composed of MNP functionalized with the cytotoxic drug gemcitabine (MNP-GEM) has been thoroughly evaluated. The linker employed is based on a disulfide bond and allows the controlled release of GEM under a highly reducing environment, which is frequently present in the cytoplasm of tumor cells. The stability, MH, and the interaction with plasma proteins of the nanoparticles are evaluated, highlighting their great potential for biological applications. Their cytotoxicity is assessed in three pancreatic cancer cell lines with different sensitivity to GEM, including the generation of reactive oxygen species (ROS), the effects on the cell cycle, and the mechanisms of cell death involved. Remarkably, the proposed nanocarrier is better internalized than unmodified nanoparticles, and it is particularly effective in PANC-1 cells, resistant to GEM, but not in non-tumoral keratinocytes. Additionally, its combination with MH produces a synergistic cytotoxic effect in all cancer cell lines tested. In conclusion, MNP-GEM presents a promising potential for treating pancreatic cancer, due to multiple parameters, such as reduced binding to plasma proteins, increased internalization, and synergistic activity when combined with MH.

Engineering nanomedicine for glutathione depletion-augmented cancer therapy

Glutathione (GSH), the main redox buffer, has long been recognized as a pivotal modulator of tumor initiation, progression and metastasis. It is also implicated in the resistance of platinum-based chemotherapy and radiation therapy. Therefore, depleting intracellular GSH was considered a potent solution to combating cancer. However, reducing GSH within cancer cells alone always failed to yield desirable therapeutic effects. In this regard, the convergence of GSH-scavenging agents with therapeutic drugs has thus been pursued in clinical practice. Unfortunately, the therapeutic outcomes are still unsatisfactory due to untargeted drug delivery. Advanced nanomedicine of synergistic GSH depletion and cancer treatment has attracted tremendous interest because they promise to deliver superior therapeutic benefits while alleviating life-threatening side effects. In the past five years, the authors and others have demonstrated that numerous nanomedicines, by simultaneously delivering GSH-depleting agents and therapeutic components, boost not only traditional chemotherapy and radiotherapy but also multifarious emerging treatment modalities, including photodynamic therapy, sonodynamic therapy, chemodynamic therapy, ferroptosis, and immunotherapy, to name a few, and achieved decent treatment outcomes in a large number of rodent tumor models. In this review, we summarize the most recent progress in engineering nanomedicine for GSH depletion-enhanced cancer therapies. Biosynthesis of GSH and various types of GSH-consuming strategies will be briefly introduced. The challenges and perspectives of leveraging nanomedicine for GSH consumption-augmented cancer therapies will be discussed at the end.

Thiolysis of CBD arylethers for development of highly GSH-selective fluorescent probes

Thiolysis of 7-cyanobenzoxadiazole (CBD) arylether was investigated for development of GSH-selective fluorescent probes for the first time. The results demonstrate that CBD-based probes have tunable reactivities and appropriate dissociation constants for GSH, and are highly GSH-selective and suitable for bioimaging.

A Serum Metabolomic Study Reveals Changes in Metabolites During the Treatment of Lung Cancer-Bearing Mice with Anlotinib

Background

Anlotinib is a vascular endothelial growth factor receptor tyrosine kinase inhibitor recommended for the treatment of advanced lung cancer patients after at least two previous systemic chemotherapies. Currently, many patients with lung cancer do not respond well to anlotinib treatment. Therefore, the aim of this metabolomic study was to determine the internal mechanism of anlotinib action at the molecular level and to identify the potential biomarkers and pathways associated with the therapeutic effects of anlotinib.

Methods

A total of 20 male nude mice were randomly divided into 2 groups and treated with anlotinib or physiological saline. Ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry was performed to analyze the serum samples and determine the differential metabolites and pathways between anlotinib and control groups.

Results

We observed significant differences between the anlotinib and control groups, and 13 endogenous differential metabolites and 5 potential metabolic pathways were identified. Glyoxylate and dicarboxylate metabolism, tryptophan metabolism, glycine, serine and threonine metabolism, phenylalanine metabolism and valine, leucine and isoleucine biosynthesis were the most important pathways regulated by anlotinib in vivo. Notably, these 5 differential pathways were highly associated with the TCA cycle, which is important in the proliferation and apoptosis of cancer cells.

Conclusion

This serum metabolomic study revealed distinct metabolic profiles in lung cancer-bearing mice treated with anlotinib and identified differential metabolites and pathways between the anlotinib and control groups, which may provide new ideas for the clinical application of anlotinib.

Redox modulation of vitagenes via plant polyphenols and vitamin D: Novel insights for chemoprevention and therapeutic interventions based on organoid technology

Polyphenols are chemopreventive through the induction of nuclear factor erythroid 2 related factor 2 (Nrf2)-mediated proteins and anti-inflammatory pathways. These pathways, encoding cytoprotective vitagenes, include heat shock proteins, such as heat shock protein 70 (Hsp70) and heme oxygenase-1 (HO-1), as well as glutathione redox system to protect against cancer initiation and progression. Phytochemicals exhibit biphasic dose responses on cancer cells, activating at low dose, signaling pathways resulting in upregulation of vitagenes, as in the case of the Nrf2 pathway upregulated by hydroxytyrosol (HT) or curcumin and NAD/NADH-sirtuin-1 activated by resveratrol. Here, the importance of vitagenes in redox stress response and autophagy mechanisms, as well as the potential use of dietary antioxidants in the prevention and treatment of multiple types of cancer are discussed. We also discuss the possible relationship between SARS-CoV-2, inflammation and cancer, exploiting innovative therapeutic approaches with HT-rich aqueous olive pulp extract (Hidrox®), a natural polyphenolic formulation, as well as the rationale of Vitamin D supplementation. Finally, we describe innovative approaches with organoids technology to study human carcinogenesis in preclinical models from basic cancer research to clinical practice, suggesting patient-derived organoids as an innovative tool to test drug toxicity and drive personalized therapy.

Recent progress in stimuli-responsive nanosystems for inducing immunogenic cell death

Low immunogenicity and immunosuppressive tumor microenvironments are major hurdles in the application of cancer immunotherapy. To date, several immunogenic cell death (ICD) inducers have been reported to boost cancer immunotherapy by triggering ICD. ICD is characterized by the release of proinflammatory cytokines, danger-associated molecular patterns (DAMPs) and tumor associated antigens which will generate anticancer immunity by triggering adaptive immune cells. However, application of ICD inducers is limited due to severe toxicity issues and inefficient localization in the tumor microenvironment. To circumvent these challenges, stimuli-responsive nanoparticles have been exploited for improving cancer immunotherapy by limiting its toxicity. The combination of stimuli-responsive nanoparticles with an ICD inducer serves as a promising strategy for increasing the clinical applications of ICD induction in cancer immunotherapy. Here, we outline recent advances in ICD mediated by stimuli-responsive nanoparticles that may be near-infrared (NIR)-responsive, pH-responsive, redox responsive, pH and enzyme responsive, or pH and redox responsive, and evaluate their significant potential for successful clinical translation in cancer immunotherapy.

Ferroptosis in the tumor microenvironment: perspectives for immunotherapy

Targeting ferroptosis, which provokes lipid peroxidation in cancer cells, presents potentially new avenues for anticancer therapy. Recent studies have begun to explore how immune cells in the tumor microenvironment (TME) respond and adapt to lethal lipid peroxides (LPOs). A better understanding of this process in the TME is likely to uncover another side of ferroptosis in cancer immunity and promote the development of ferroptosis-targeted therapy. This Opinion article overviews the main metabolic processes in ferroptosis, summarizes the emerging roles of ferroptosis not only in immune cells in the TME but also in the crosstalk between tumor cells and immune cells, and presents a perspective on the targeting of ferroptosis in cancer immunotherapy.

Pheophorbide A and Paclitaxel Bioresponsive Nanoparticles as Double-Punch Platform for Cancer Therapy

Cancer therapy is still a challenging issue. To address this, the combination of anticancer drugs with other therapeutic modalities, such as light-triggered therapies, has emerged as a promising approach, primarily when both active ingredients are provided within a single nanosystem. Herein, we describe the unprecedented preparation of tumor microenvironment (TME) responsive nanoparticles exclusively composed of a paclitaxel (PTX) prodrug and the photosensitizer pheophorbide A (PheoA), e.g., PheoA≅PTX₂S. This system aimed to achieve both the TME-triggered and controlled release of PTX and the synergistic/additive effect by PheoA-mediated photodynamic therapy. PheoA≅PTX₂S were produced in a simple one-pot process, exhibiting excellent reproducibility, stability, and the ability to load up to 100% PTX and 40% of PheoA. Exposure of PheoA≅PTX₂S nanoparticles to TME-mimicked environment provided fast disassembly compared to normal conditions, leading to PTX and PheoA release and consequently elevated cytotoxicity. Our data indicate that PheoA incorporation into nanoparticles prevents its aggregation, thus providing a greater extent of ROS and singlet oxygen production. Importantly, in SK-OV-3 cells, PheoA≅PTX₂S allowed a 30-fold PTX dose reduction and a 3-fold dose reduction of PheoA. Our data confirm that prodrug-based nanocarriers represent valuable and sustainable drug delivery systems, possibly reducing toxicity and expediting preclinical and clinical translation.

Ferritinophagy and ferroptosis in cardiovascular disease: Mechanisms and potential applications

Ferroptosis is a type of regulated cell death driven by iron dependent accumulation of cellular reactive oxygen species (ROS) when glutathione (GSH)-dependent lipid peroxidation repair systems are compromised. Nuclear receptor co-activator 4 (NCOA4)-mediated selective autophagy of ferritin, termed ferritinophagy, involves the regulation of ferroptosis. Emerging evidence has revealed that ferritinophagy and ferroptosis exert a significant role in the occurrence and development of cardiovascular disease. In the present review, we aimed to present a brief overview of ferritinophagy and ferroptosis focusing on the underlying mechanism and regulations involved. We summarize and discuss relevant research progress on the role of ferritinophagy and ferroptosis in cardiovascular diseases accompanied with potential applications of ferritinophagy and ferroptosis modulators in the treatment of ferroptosis-associated cardiovascular diseases.

In vivo therapeutic evaluation of a novel bis-lawsone derivative against tumor following delivery using mesoporous silica nanoparticle based redox-responsive drug delivery system

Herein, we have evaluated the in vivo therapeutic efficacy and systemic toxicity profile of a synthetic anticancer compound [3,3'-((4-(trifluoromethyl)phenyl)methylene)bis(2-hydroxynaphthalene-1,4-dione)]. A multifunctional mesoporous silica nanoparticle (MSN) based drug delivery network was also fabricated which specifically showed targeting nature towards the cancer cell. The mesopores of silica nanoparticles were tagged with phenyl boronic acid (PBA) for targeted drug delivery into tumor tissue. 1j was then loaded inside the nanocarriers followed by pore blocking with gold nanoparticles (GN) to attain a redox-responsive controlled drug delivery pattern. The synthesized nanocarriers (1j@-MSN-PBA-GN) having mean diameter of ~86 nm exhibited a moderate 1j loading content of 13.68% with overall negative surface charge. Both the targeted and non-targeted nanoformulations were tested for their anticancer activities both in vitro and in vivo models, and found more effective as compared with free 1j treatment. However, the targeted nanoformulations showed higher therapeutic effect due to increased cellular internalization and caused mitochondria-dependent apoptosis in MCF-7 cells via oxidative stress. Besides, the targeted nanoformulation significantly inhibited in the development of solid tumor in comparison to non-targeted nanoformulations and free 1j as a consequence of increased internalization of the drug-candidate in tumor tissue. Therefore, this study proposes that 1j can be considered as a potent anti-carcinogenic compound in vivo and its therapeutic potential is further increased by using PBA functionalized and GN gated MSN-based controlled drug delivery system without showing any significant systemic toxicity.

Immunity Depletion, Telomere Imbalance, and Cancer-Associated Metabolism Pathway Aberrations in Intestinal Mucosa upon Short-Term Caloric Restriction

Systems cancer biology analysis of calorie restriction (CR) mechanisms and pathways has not been carried out, leaving therapeutic benefits unclear. Using metadata analysis, we studied gene expression changes in normal mouse duodenum mucosa (DM) response to short-term (2-weeks) 25% CR as a biological model. Our results indicate cancer-associated genes consist of 26% of 467 CR responding differential expressed genes (DEGs). The DEGs were enriched with over-expressed cell cycle, oncogenes, and metabolic reprogramming pathways that determine tissue-specific tumorigenesis, cancer, and stem cell activation; tumor suppressors and apoptosis genes were under-expressed. DEG enrichments suggest telomeric maintenance misbalance and metabolic pathway activation playing dual (anti-cancer and pro-oncogenic) roles. The aberrant DEG profile of DM epithelial cells is found within CR-induced overexpression of Paneth cells and is coordinated significantly across GI tract tissues mucosa. Immune system genes (ISGs) consist of 37% of the total DEGs; the majority of ISGs are suppressed, including cell-autonomous immunity and tumor-immune surveillance. CR induces metabolic reprogramming, suppressing immune mechanics and activating oncogenic pathways. We introduce and argue for our network pro-oncogenic model of the mucosa multicellular tissue response to CR leading to aberrant transcription and pre-malignant states. These findings change the paradigm regarding CR's anti-cancer role, initiating specific treatment target development. This will aid future work to define critical oncogenic pathways preceding intestinal lesion development and biomarkers for earlier adenoma and colorectal cancer detection.

Albumin-Based Nanoparticles for the Delivery of Doxorubicin in Breast Cancer

Albumin-based nanoparticles are an emerging platform for the delivery of various chemotherapeutics because of their biocompatibility, safety, and ease of surface modification for specific targeting. The most widely used method for the preparation of albumin nanoparticles is by desolvation process using glutaraldehyde (GLU) as a cross-linker. However, limitations of GLU like toxicity and interaction with drugs force the need for alternative cross-linkers. In the present study, several cross-linking systems were evaluated for the preparation of Bovine Serum Albumin (BSA) nanoparticles (ABNs) encapsulating Doxorubicin (Dox). Based on the results obtained from morphological characterization, in vitro release, and therapeutic efficacy in cells, N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP)-modified ABNs (ABN-SPDP) was chosen. Since ABN-SPDP are formed with disulfide linkage, the drug release is facilitated under a highly reducing environment present in the tumor sites. The cytotoxicity studies of those ABN-SPDP were performed in three different breast cell lines, highlighting the mechanism of cell death. The Dox-encapsulated ABN-SPDP showed toxicity in both the breast cancer cells (MCF-7 and MDA-MB-231), but, remarkably, a negligible effect was observed in non-tumoral MCF-10A cells. In addition to the hydrophilic Dox, this system could be used as a carrier for hydrophobic drugs like SN38. The system could be employed for the preparation of nanoparticles based on human serum albumin (HSA), which further enhances the feasibility of this system for clinical use. Hence, the albumin nanoparticles developed herein present an excellent potential for delivering various drugs in cancer therapy.

Implications of Oxidative Stress in Glioblastoma Multiforme Following Treatment with Purine Derivatives

Recently, small compound-based therapies have provided new insights into the treatment of glioblastoma multiforme (GBM) by inducing oxidative impairment. Kinetin riboside (KR) and newly designed derivatives (8-azaKR, 7-deazaKR) selectively affect the molecular pathways crucial for cell growth by interfering with the redox status of cancer cells. Thus, these compounds might serve as potential alternatives in the oxidative therapy of GBM. The increased basal levels of reactive oxygen species (ROS) in GBM support the survival of cancer cells and cause drug resistance. The simplest approach to induce cell death is to achieve the redox threshold and circumvent the antioxidant defense mechanisms. Consequently, cells become more sensitive to oxidative stress (OS) caused by exogenous agents. Here, we investigated the effect of KR and its derivatives on the redox status of T98G cells in 2D and 3D cell culture. The use of spheroids of T98G cells enabled the selection of one derivative-7-deazaKR-with comparable antitumor activity to KR. Both compounds induced ROS generation and genotoxic OS, resulting in lipid peroxidation and leading to apoptosis. Taken together, these results demonstrated that KR and 7-deazaKR modulate the cellular redox environment of T98G cells, and vulnerability of these cells is dependent on their antioxidant capacity.

Photodynamic Therapy-Current Limitations and Novel Approaches

Photodynamic therapy (PDT) mostly relies on the generation of singlet oxygen, via the excitation of a photosensitizer, so that target tumor cells can be destroyed. PDT can be applied in the settings of several malignant diseases. In fact, the earliest preclinical applications date back to 1900’s. Dougherty reported the treatment of skin tumors by PDT in 1978. Several further studies around 1980 demonstrated the effectiveness of PDT. Thus, the technique has attracted the attention of numerous researchers since then. Hematoporphyrin derivative received the FDA approval as a clinical application of PDT in 1995. We have indeed witnessed a considerable progress in the field over the last century. Given the fact that PDT has a favorable adverse event profile and can enhance anti-tumor immune responses as well as demonstrating minimally invasive characteristics, it is disappointing that PDT is not broadly utilized in the clinical setting for the treatment of malignant and/or non-malignant diseases. Several issues still hinder the development of PDT, such as those related with light, tissue oxygenation and inherent properties of the photosensitizers. Various photosensitizers have been designed/synthesized in order to overcome the limitations. In this Review, we provide a general overview of the mechanisms of action in terms of PDT in cancer, including the effects on immune system and vasculature as well as mechanisms related with tumor cell destruction. We will also briefly mention the application of PDT for non-malignant diseases. The current limitations of PDT utilization in cancer will be reviewed, since identifying problems associated with design/synthesis of photosensitizers as well as application of light and tissue oxygenation might pave the way for more effective PDT approaches. Furthermore, novel promising approaches to improve outcome in PDT such as selectivity, bioengineering, subcellular/organelle targeting, etc. will also be discussed in detail, since the potential of pioneering and exceptional approaches that aim to overcome the limitations and reveal the full potential of PDT in terms of clinical translation are undoubtedly exciting. A better understanding of novel concepts in the field (e.g. enhanced, two-stage, fractional PDT) will most likely prove to be very useful for pursuing and improving effective PDT strategies.

Investigating the antimicrobial, antioxidant and cytotoxic activities of the biological synthesized glutathione selenium nano-incorporation

Aqueous glutathione selenium nano-incorporation (GSH-SeN-Inco) was prepared by gamma radiation in presence of microbial glutathione (GSH) and selenium dioxide. The novel prepared GSH-SeN-Inco are validated by UV-vis spectroscopy, TEM (17.5 nm), DLS, XRD, EDX and FTIR spectrum reveals the presence of GSH moiety that coating the selenium nanoparticles (SeNPs) forming GSH-SeN-Inco. The XRD analysis verified the presence of metallic SeNPs. The nucleation and radiolysis mechanism of GSH-SeN-Inco formation are also discussed. The size GSH-SeN-Inco (17.5 nm) is affected by certain factors such as concentration of GSH, selenium dioxide, and absorbed dose of gamma radiation. The present study explored the positive role of GSH-SeN-Inco as an antitumor activity against HepG-2 and MCF-7, with IC₅₀ at a concentration of 1.00 and 0.9 mM, respectively. The GSH-SeN-Inco show significant scavenging activity at 33%. The GSH-SeN-Inco shows antimicrobial potential against Gram-negative and Gram-positive bacteria with significant MIC especially Escherichia coli ATCC 25922 at 5.20 µg/ml.

Characteristics of P-Type and N-Type Photoelectrochemical Biosensors: A Case Study for Esophageal Cancer Detection

P-type and N-type photoelectrochemical (PEC) biosensors were established in the laboratory to discuss the correlation between characteristic substances and photoactive material properties through the photogenerated charge carrier transport mechanism. Four types of human esophageal cancer cells (ECCs) were analyzed without requiring additional bias voltage. Photoelectrical characteristics were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV–vis reflectance spectroscopy, and photocurrent response analyses. Results showed that smaller photocurrent was measured in cases with advanced cancer stages. Glutathione (L-glutathione reduced, GSH) and Glutathione disulfide (GSSG) in cancer cells carry out redox reactions during carrier separation, which changes the photocurrent. The sensor can identify ECC stages with a certain level of photoelectrochemical response. The detection error can be optimized by adjusting the number of cells, and the detection time of about 5 min allowed repeated measurement.

Hyaluronic Acid-Targeted Stimuli-Sensitive Nanomicelles Co-Encapsulating Paclitaxel and Ritonavir to Overcome Multi-Drug Resistance in Metastatic Breast Cancer and Triple-Negative Breast Cancer Cells

Active targeting and overcoming multi-drug resistance (MDR) can be some of the important attributes of targeted therapy for metastatic breast cancer (MBC) and triple-negative breast cancer (TNBC) treatment. In this study, we constructed a hyaluronic acid (HA)-decorated mixed nanomicelles-encapsulating chemotherapeutic agent paclitaxel (PTX) and P-glycoprotein inhibitor ritonavir (RTV). HA was conjugated to poly (lactide) co-(glycolide) (PLGA) polymer by disulfide bonds (HA-ss-PLGA). HA is a natural ligand for CD44 receptors overexpressed in breast cancer cells. Disulfide bonds undergo rapid reduction in the presence of glutathione, present in breast cancer cells. The addition of RTV can inhibit the P-gp and CYP3A4-mediated metabolism of PTX, thus aiding in reversing MDR and sensitizing the cells toward PTX. An in vitro uptake and cytotoxicity study in MBC MCF-7 and TNBC MDA-MB-231 cell lines demonstrated the effective uptake of the nanomicelles and drug PTX compared to non-neoplastic breast epithelium MCF-12A cells. Interestingly, in vitro potency determination showed a reduction in mitochondrial membrane potential and reactive oxygen species in breast cancer cell lines, indicating effective apoptosis of cancer cells. Thus, stimuli-sensitive nanomicelles along with HA targeting and RTV addition can effectively serve as a chemotherapeutic drug delivery agent for MBC and TNBC.