Reactive oxygen species-dependent signaling regulates cancer

Dual roles of methylglyoxal in cancer

Cancer treatment currently includes a variety of approaches. Chemotherapy, targeted therapy, and immunotherapy are combined based on cancer characteristics to develop personalized treatment plans. However, drug resistance can hinder the progress of treatment over time. Methylglyoxal (MG) is a metabolite with hormesis, exhibiting both pro-tumor and anti-tumor actions depending on its concentration during cancer progression. The MG-related metabolic pathway is being explored in the development of anti-cancer drugs, focusing on reducing MG stress or exploiting its cytotoxic effects to inhibit cancer progression. This article investigates the dual role of MG in cancer, emphasizing its effects on cell metabolism and tumor progression. It proposes MG capture therapy for the pre-cancerous stage and MG toxicity therapy for the cancer stage, contributing to the development of precise and individualized cancer treatments.

Current Perspective and Mechanistic Insights on α-Hederin for the Prevention and Treatment of Several Noncommunicable Diseases

α-Hederin, a naturally occurring compound found in various plant sources, has remarkable properties and therapeutic potential for human health. One notable attribute is its potent anti-inflammatory activity, such as in arthritis, asthma, and inflammatory bowel disease. In addition, it exhibits notable antioxidant effects implicated in the development of chronic diseases, including cardiovascular disorders and certain types of cancer. According to research, it may limit the growth and proliferation of cancer cells, making it a possible candidate for future cancer treatments. Moreover, it is a promising neuroprotective agent and enhances cognitive function, suggesting its potential in the treatment of neurodegenerative illnesses like Alzheimer's and Parkinson's disease. The multifaceted benefits of α-hederin make it an intriguing compound with significant therapeutic implications. As research progresses, exploring its mechanisms of action and clinical applications is warranted. Harnessing the potential of α-hederin may pave the way for innovative treatment strategies and improved outcomes in the battle against various chronic diseases.

A Multi-Omics Analysis of a Mitophagy-Related Signature in Pan-Cancer

Mitophagy, an essential process within cellular autophagy, has a critical role in regulating key cellular functions such as reproduction, metabolism, and apoptosis. Its involvement in tumor development is complex and influenced by the cellular environment. Here, we conduct a comprehensive analysis of a mitophagy-related gene signature, composed of PRKN, PINK1, MAP1LC3A, SRC, BNIP3L, BECN1, and OPTN, across various cancer types, revealing significant differential expression patterns associated with molecular subtypes, stages, and patient outcomes. Pathway analysis revealed a complex interplay between the expression of the signature and potential effects on the activity of various cancer-related pathways in pan-cancer. Immune infiltration analysis linked the mitophagy signature with certain immune cell types, particularly OPTN with immune infiltration in melanoma. Methylation patterns correlated with gene expression and immune infiltration. Mutation analysis also showed frequent alterations in PRKN (34%), OPTN (21%), PINK1 (28%), and SRC (15%), with implications for the tumor microenvironment. We also found various correlations between the expression of the mitophagy-related genes and sensitivity in different drugs, suggesting that targeting this signature could improve therapy efficacy. Overall, our findings underscore the importance of mitophagy in cancer biology and drug resistance, as well as its potential for informing treatment strategies.

Small molecules targeting mitochondria as an innovative approach to cancer therapy

Cellular death evasion is a defining characteristic of human malignancies and a significant contributor to therapeutic inefficacy. As a result of oncogenic inhibition of cell death mechanisms, established therapeutic regimens seems to be ineffective. Mitochondria serve as the cellular powerhouses, but they also function as repositories of self-destructive weaponry. Changes in the structure and activities of mitochondria have been consistently documented in cancer cells. In recent years, there has been an increasing focus on using mitochondria as a targeted approach for treating cancer. Considerable attention has been devoted to the development of delivery systems that selectively aim to deliver small molecules called "mitocans" to mitochondria, with the ultimate goal of modulating the physiology of cancer cells. This review summarizes the rationale and mechanism of mitochondrial targeting with small molecules in the treatment of cancer, and their impact on the mitochondria. This paper provides a concise overview of the reasoning and mechanism behind directing treatment towards mitochondria in cancer therapy, with a particular focus on targeting using small molecules. This review also examines diverse small molecule types within each category as potential therapeutic agents for cancer.

In vitro cytotoxic activity on KATO-III cancer cell lines of mangiferolic acid purified from Thai Tetragonula laeviceps propolis

Gastric cancer is a global health concern, but current treatment with chemotherapy and surgery is often inadequate, prompting the exploration of alternative treatments. Propolis is a natural substance collected by bees known for its diverse properties linked to floral sources. The Dichloromethane Partitioned Extract (DPE) from Tetragonula laeviceps propolis, in Bankha district, Thailand was previously shown to possess significant cytotoxicity against KATO-III gastric cancer cells, while showing lower cytotoxicity toward WI-38 normal fibroblast cells. Here, the DPE was further fractionated by column chromatography, identified active fractions, and subjected to structural analysis using nuclear magnetic resonance spectroscopy. Cytotoxicity against KATO-III cells was reevaluated, and programmed cell death was analyzed using flow cytometry. Expression levels of cancer-related genes were measured using quantitative real-time reverse transcriptase PCR. Cardol C15:2 (compound 1) and mangiferolic acid (MF; compound 2) were discovered in the most active fractions following structural analysis. MF exhibited strong cytotoxicity against KATO-III cells (IC50 of 4.78-16.02 μg/mL), although this was less effective than doxorubicin (IC50 of 0.56-1.55 μg/mL). Morphological changes, including decreased cell density and increased debris, were observed in KATO-III cells treated with 30 μg/mL of MF. Significant induction of late-stage apoptosis and necrosis, particularly at 48 and 72 h, suggested potential DNA damage and cell cycle arrest, evidenced by an increased proportion of sub-G1 and S-phase cells. Doxorubicin, the positive control, triggered late apoptosis but caused more necrosis after 72 h. Furthermore, MF at 30 μg/mL significantly increased the expression level of COX2 and NFκB genes linked to inflammation and cell death pathways. This upregulation was consistent at later time points (48 and 72 h) and was accompanied by increased expression of CASP3 and CASP7 genes. These findings suggest MF effectively induces cell death in KATO-III cells through late apoptosis and necrosis, potentially mediated by upregulated inflammation-related genes.

Interactions and Transport of a Bioconjugated Peptide Targeting the Mitomembrane

The Szeto-Schiller (SS) peptides are a subclass of cell-penetrating peptides that can specifically target mitochondria and mediate conditions caused by mitochondrial dysfunction. In this work, we constructed an iron-chelating SS peptide and studied its interaction with a mitochondrial-mimicking membrane using atomistic molecular dynamics (MD) simulations. We report that the peptide/membrane interaction is thermodynamically favorable, and the localization of the peptide to the membrane is driven by electrostatic interactions between the cationic residues and the anionic phospholipid headgroups. The insertion of the peptide into the membrane is driven by hydrophobic interactions between the aromatic side chains in the peptide and the lipid acyl tails. We also probed the translocation of the peptide across the membrane by applying nonequilibrium steered MD simulations and resolved the translocation pathway, free energy profile, and metastable states. We explored four distinct orientations of the peptide along the translocation pathway and found that one orientation was energetically more favorable than the other orientations. We tested a significantly slower pulling velocity on the most thermodynamically favorable system and compared metastable states during peptide translocation. We found that the peptide can optimize hydrophobic interactions with the membrane by having aromatic side chains interacting with the lipid acyl tails instead of forming π-π interactions with each other. The mechanistic insights emerging from our work will potentially facilitate improved peptide design with enhanced activity.

Mitochondria driven innate immune signaling and inflammation in cancer growth, immune evasion, and therapeutic resistance

Mitochondria play an important and multifaceted role in cellular function, catering to the cell's energy and biosynthetic requirements. They modulate apoptosis while responding to diverse extracellular and intracellular stresses including reactive oxygen species (ROS), nutrient and oxygen scarcity, endoplasmic reticulum stress, and signaling via surface death receptors. Integral components of mitochondria, such as mitochondrial DNA (mtDNA), mitochondrial RNA (mtRNA), Adenosine triphosphate (ATP), cardiolipin, and formyl peptides serve as major damage-associated molecular patterns (DAMPs). These molecules activate multiple innate immune pathways both in the cytosol [such as Retionoic Acid-Inducible Gene-1 (RIG-1) and Cyclic GMP-AMP Synthase (cGAS)] and on the cell surface [including Toll-like receptors (TLRs)]. This activation cascade leads to the release of various cytokines, chemokines, interferons, and other inflammatory molecules and oxidative species. The innate immune pathways further induce chronic inflammation in the tumor microenvironment which either promotes survival and proliferation or promotes epithelial to mesenchymal transition (EMT), metastasis and therapeutic resistance in the cancer cell's. Chronic activation of innate inflammatory pathways in tumors also drives immunosuppressive checkpoint expression in the cancer cells and boosts the influx of immune-suppressive populations like Myeloid-Derived Suppressor Cells (MDSCs) and Regulatory T cells (Tregs) in cancer. Thus, sensing of cellular stress by the mitochondria may lead to enhanced tumor growth. In addition to that, the tumor microenvironment also becomes a source of immunosuppressive cytokines. These cytokines exert a debilitating effect on the functioning of immune effector cells, and thus foster immune tolerance and facilitate immune evasion. Here we describe how alteration of the mitochondrial homeostasis and cellular stress drives innate inflammatory pathways in the tumor microenvironment.

Mitochondria at the Nanoscale: Physics Meets Biology-What Does It Mean for Medicine?

Mitochondria are commonly perceived as "cellular power plants". Intriguingly, power conversion is not their only function. In the first part of this paper, we review the role of mitochondria in the evolution of eukaryotic organisms and in the regulation of the human body, specifically focusing on cancer and autism in relation to mitochondrial dysfunction. In the second part, we overview our previous works, revealing the physical principles of operation for proton-pumping complexes in the inner mitochondrial membrane. Our proposed simple models reveal the physical mechanisms of energy exchange. They can be further expanded to answer open questions about mitochondrial functions and the medical treatment of diseases associated with mitochondrial disorders.

Reactive oxygen species and its role in pathogenesis and resistance to therapy in acute myeloid leukemia

Relapse following a short clinical response to therapy is the major challenge for the management of acute myeloid leukemia (AML) patients. Leukemic stem cells (LSC), as the source of relapse, have been investigated for their metabolic preferences and their alterations at the time of relapse. As LSC rely on oxidative phosphorylation (OXPHOS) for energy requirement, reactive oxygen species (ROS), as by-products of OXPHOS, have been investigated for their role in the effectiveness of the standard AML therapy. Increased levels of non-mitochondrial ROS, generated by nicotinamide adenine dinucleotide phosphate oxidase, in a subgroup of AML patients add to the complexity of studying ROS. Although there are various studies presenting the contribution of ROS to AML pathogenesis, resistance, and its inhibition or activation as a target, a model that can clearly explain its role in AML has not been conceptualized. This is due to the heterogeneity of AML, the dynamics of ROS production, which is influenced by factors such as the type of treatment, cell differentiation state, mitochondrial activity, and also the heterogeneous generation of non-mitochondrial ROS and limited available data on their interaction with the microenvironment. This review summarizes these challenges and the recent progress in this field.

Implications and progression of peroxiredoxin 2 (PRDX2) in various human diseases

Peroxiredoxin 2 (PRDX2), a characteristic 2-Cys enzyme is one of the foremost effective scavenger proteins against reactive oxygen species (ROS) and hydrogen peroxide (H2O2) defending cells against oxidative stress. Dysregulation of this antioxidant raises the quantity of ROS and oxidative stress implicated in several diseases. PRDX2 lowers the generation of ROS that takes part in controlling several signalling pathways occurring in neurons, protecting them from stress caused by oxidation and an inflammatory harm. Depending on the aetiological variables, the kind of cancer, and the stage of tumour development, PRDX2 may behave either as an onco-suppressor or a promoter. However, overexpression of PRDX2 may be linked to the development of numerous cancers, including those of the colon, cervix, breast, and prostate. PRDX2 also plays a beneficial effect in inflammatory diseases. PRDX2 being a thiol-specific peroxidase, is known to control proinflammatory reactions. The spilling of PRDX2, on the other hand, accelerates cognitive impairment following a stroke by triggering an inflammatory reflex. PRDX2 expression patterns in vascular cells tend to be crucial to its involvement in cardiovascular diseases. In vascular smooth muscle cells, if the protein tyrosine phosphatase is restricted, PRDX2 could avoid the neointimal thickening which relies on platelet derived growth factor (PDGF), a vital component of vascular remodelling. A proper PRDX2 balance is therefore crucial. The imbalance causes a number of illnesses, including cancers, inflammatory diseases, cardiovascular ailments, and neurological and neurodegenerative problems which are discussed in this review.

Relevance of the endoplasmic reticulum-mitochondria axis in cancer diagnosis and therapy

Dynamic interactions between organelles are responsible for a variety of intercellular functions, and the endoplasmic reticulum (ER)-mitochondrial axis is recognized as a representative interorganelle system. Several studies have confirmed that most proteins in the physically tethered sites between the ER and mitochondria, called mitochondria-associated ER membranes (MAMs), are vital for intracellular physiology. MAM proteins are involved in the regulation of calcium homeostasis, lipid metabolism, and mitochondrial dynamics and are associated with processes related to intracellular stress conditions, such as oxidative stress and unfolded protein responses. Accumulating evidence has shown that, owing to their extensive involvement in cellular homeostasis, alterations in the ER-mitochondrial axis are one of the etiological factors of tumors. An in-depth understanding of MAM proteins and their impact on cell physiology, particularly in cancers, may help elucidate their potential as diagnostic and therapeutic targets for cancers. For example, the modulation of MAM proteins is utilized not only to target diverse intracellular signaling pathways within cancer cells but also to increase the sensitivity of cancer cells to anticancer reagents and regulate immune cell activities. Therefore, the current review summarizes and discusses recent advances in research on the functional roles of MAM proteins and their characteristics in cancers from a diagnostic perspective. Additionally, this review provides insights into diverse therapeutic strategies that target MAM proteins in various cancer types.

Development of a novel hypochlorite ratio probe based on coumarin and its application in living cells

Hypochlorous acid is a reactive oxygen species that is widely present in the body and has been found to exhibit an elevated concentration in tumors. As a result, fluorescent probes for tumor detection have recently gained significant attention. In this study, we designed and synthesized a novel ratiometric fluorescent probe, LW-1, using coumarin as a scaffold, and characterized its spectral properties. LW-1 displayed indigo blue fluorescence at low concentrations of hypochlorous acid. As the concentration of hypochlorous acid increased, the probe underwent a reaction, resulting in a red shift in its fluorescence peak and exhibiting green fluorescence. The fluorescence intensity ratio (green/blue) was a susceptible detection signal for HClO. LW-1 exhibited favorable characteristics, including a low detection limit, high sensitivity, good stability, and low background interference. The detection limit has reached 2.4642 nM. Moreover, we successfully employed LW-1 to image normal human liver and colon cancer cells in vitro, demonstrating its potential as a promising tool for tumor detection. Overall, our findings suggest that LW-1 could serve as a valuable addition to the current arsenal of fluorescent probes for tumor detection, with potential applications in the diagnosis and treatment of cancer.

Specific and Long-Term Luminescent Monitoring of Hydrogen Peroxide in Tumor Metastasis

Luminescent monitoring of endogenous hydrogen peroxide (H₂ O₂ ) in tumors is conducive to understanding metastasis and developing novel therapeutics. The clinical transformation is obstructed by the limited light penetration depth, toxicity of nano-probes, and lack of long-term monitoring modes of up to days or months. New monitoring modes are introduced via specific probes and implantable devices, which can achieve real-time monitoring with a readout frequency of 0.01 s or long-term monitoring for months to years. Near-infrared dye-sensitized upconversion nanoparticles (UCNPs) are fabricated as the luminescent probes, and the specificity to reactive oxygen species is subtly regulated by the self-assembled monolayers on the surfaces of UCNPs. Combined with the passive implanted system, a 20-day monitoring of H₂ O₂ in the rat model of ovarian cancer with peritoneal metastasis is achieved, in which the limited light penetration depth and toxicity of nano-probes are circumvented. The developed monitoring modes show great potential in accelerating the clinical transformation of nano-probes and biochemical detection methods.

Antioxidant and Anti-Tumor Effects of Dietary Vitamins A, C, and E

Oxidative stress, a condition characterized by an imbalance between pro-oxidant molecules and antioxidant defense systems, is increasingly recognized as a key contributor to cancer development. This is because the reactive oxygen species (ROS) generated during oxidative stress can damage DNA, proteins, and lipids to facilitate mutations and other cellular changes that promote cancer growth. Antioxidant supplementation is a potential strategy for decreasing cancer incidence; by reducing oxidative stress, DNA damage and other deleterious cellular changes may be attenuated. Several clinical trials have been conducted to investigate the role of antioxidant supplements in cancer prevention. Some studies have found that antioxidant supplements, such as vitamin A, vitamin C, and vitamin E, can reduce the risk of certain types of cancer. On the other hand, some studies posit an increased risk of cancer with antioxidant supplement use. In this review, we will provide an overview of the current understanding of the role of oxidative stress in cancer formation, as well as the potential benefits of antioxidant supplementation in cancer prevention. Additionally, we will discuss both preclinical and clinical studies highlighting the potentials and limitations of preventive antioxidant strategies.

Hypothesis: can transfer of primary neoplasm-derived extracellular vesicles and mitochondria contribute to the development of donor cell-derived hematologic neoplasms after allogeneic hematopoietic cell transplantation?

Allogeneic hematopoietic cell transplantation (allo-HCT) is an essential treatment option for various neoplastic and non-neoplastic hematologic diseases. Although its efficacy is modest, a significant proportion of patients experience relapse, graft-versus-host disease, infection or impaired hematopoiesis. Among these, the most frequent cause of post-transplant mortality is relapse, whereas the development of de novo hematologic neoplasms from donor cells after allo-HCT occurs on some occasion as a rare complication. The mechanisms involved in the pathogenesis of the de novo hematologic neoplasms from donor cells are complex, and a multifactorial process contributes to the development of this complication. Recently, extracellular vesicles, particularly exosomes, and mitochondria have been shown to play crucial roles in intercellular communication through the transfer of specific constituents, such as deoxyribonucleic acids, ribonucleic acids, lipids, metabolites and cytosolic and cell-surface proteins. Here, I discuss the potential causative roles of these subcellular components in the development of de novo hematologic neoplasms from donor cells after allo-HCT, in addition to other etiologies.

Possible Synergies of Nanomaterial-Assisted Tissue Regeneration in Plasma Medicine: Mechanisms and Safety Concerns

Cold atmospheric plasma and nanomedicine originally emerged as individual domains, but are increasingly applied in combination with each other. Most research is performed in the context of cancer treatment, with only little focus yet on the possible synergies. Many questions remain on the potential of this promising hybrid technology, particularly regarding regenerative medicine and tissue engineering. In this perspective article, we therefore start from the fundamental mechanisms in the individual technologies, in order to envision possible synergies for wound healing and tissue recovery, as well as research strategies to discover and optimize them. Among these strategies, we demonstrate how cold plasmas and nanomaterials can enhance each other's strengths and overcome each other's limitations. The parallels with cancer research, biotechnology and plasma surface modification further serve as inspiration for the envisioned synergies in tissue regeneration. The discovery and optimization of synergies may also be realized based on a profound understanding of the underlying redox- and field-related biological processes. Finally, we emphasize the toxicity concerns in plasma and nanomedicine, which may be partly remediated by their combination, but also partly amplified. A widespread use of standardized protocols and materials is therefore strongly recommended, to ensure both a fast and safe clinical implementation.

High-efficiency quantitative control of mitochondrial transfer based on droplet microfluidics and its application on muscle regeneration

Mitochondrial transfer is a spontaneous process to restore damaged cells in various pathological conditions. The transfer of mitochondria to cell therapy products before their administration can enhance therapeutic outcomes. However, the low efficiency of previously reported methods limits their clinical application. Here, we developed a droplet microfluidics-based mitochondrial transfer technique that can achieve high-efficiency and high-throughput quantitative mitochondrial transfer to single cells. Because mitochondria are essential for muscles, myoblast cells and a muscle injury model were used as a proof-of-concept model to evaluate the proposed technique. In vitro and in vivo experiments demonstrated that C2C12 cells with 31 transferred mitochondria had significant improvements in cellular functions compared to those with 0, 8, and 14 transferred mitochondria and also had better therapeutic effects on muscle regeneration. The proposed technique can considerably promote the clinical application of mitochondrial transfer, with optimized cell function improvements, for the cell therapy of mitochondria-related diseases.

OGG1 in Lung—More than Base Excision Repair

As the organ executing gas exchange and directly facing the external environment, the lungs are challenged continuously by various stimuli, causing the disequilibration of redox homeostasis and leading to pulmonary diseases. The breakdown of oxidants/antioxidants system happens when the overproduction of free radicals results in an excess over the limitation of cleaning capability, which could lead to the oxidative modification of macromolecules including nucleic acids. The most common type of oxidative base, 8-oxoG, is considered the marker of DNA oxidative damage. The appearance of 8-oxoG could lead to base mismatch and its accumulation might end up as tumorigenesis. The base 8-oxoG was corrected by base excision repair initiated by 8-oxoguanine DNA glycosylase-1 (OGG1), which recognizes 8-oxoG from the genome and excises it from the DNA double strand, generating an AP site for further processing. Aside from its function in DNA damage repairment, it has been reported that OGG1 takes part in the regulation of gene expression, derived from its DNA binding characteristic, and showed impacts on inflammation. Researchers believe that OGG1 could be the potential therapy target for relative disease. This review intends to make an overall summary of the mechanism through which OGG1 regulates gene expression and the role of OGG1 in pulmonary diseases.

Multifunctional DNAzyme-Anchored Metal-Organic Framework for Efficient Suppression of Tumor Metastasis

High mortality and rapid development of metastasis requires the development of more effective antimetastasis strategies. However, conventional therapeutic methods, including surgery, radiation therapy, and chemotherapy, show less effectiveness in curbing the metastatic spread of cancer cells and the formation of metastases. A therapeutic platform, targeting the early stage of metastasis cascade, could effectively prevent metastasis dissemination. Herein, Fe/Mn-based metal-organic frameworks (FMM) were constructed for the delivery of a specific DNAzyme with high catalytic cleavage activity on the metastasis-involved Twist mRNA, thus efficiently inhibiting the invasion of cancer cells through DNAzyme-catalyzed gene silencing. Highly potent combined gene/chemodynamic therapy is achieved from the self-supplied DNAzyme cofactors and efficient glutathione depletion. Importantly, by virtue of the intrinsic photo-to-thermal conversion of the FMM nanocarriers, our combined therapeutic strategy could be further promoted under photothermal stimuli to speed up the Fenton reaction and to accelerate the release of the Twist DNAzyme with efficient gene therapy. Consequently, the effective elimination of tumors and the blockage of metastasis are simultaneously achieved under photothermal/magnetic resonance imaging guidance. This work aims at developing versatile theranostic agents to combat metastatic tumors.

Oncogenic Kras-Mediated Cytokine CCL15 Regulates Pancreatic Cancer Cell Migration and Invasion through ROS

Simple Summary

Oncogenic Kras^G12D and tumor inflammation are critical components of the development and dissemination of pancreatic ductal adenocarcinoma (PDAC). The aim of this study is to investigate a lesser-known cytokine, CCL15, that functions as a new downstream target of Kras^G12D with the purpose of regulating PDAC cell migration and invasion. We showed increased levels of CCL15 as well as the presence of its receptors, including CCR1 and CCR3, in PDAC tissues and cell lines. The knockdown of CCL15 diminished metastatic Panc-1 cell migration, whereas the treatment of CCL15 in non-metastatic BxPC-3 cells promoted BxPC-3 cell motility. Similar results were verified using murine metastatic PDAC KP-2 cells. Furthermore, we demonstrated that CCL15-modulated PDAC cell migration through the upregulation of cellular reactive oxygen species (ROS) levels and the knockdown of Kras^G12D resulted in a decrease in CCL15. Altogether, our data unveiled a new mechanism of oncogenic Kras^G12D in modulating PDAC inflammation and spreading.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is well known for its high death rate due to prompt cancer metastasis caused by cancer cell migration and invasion within the early stages of its development. Here, we reveal a new function of cytokine CCL15, namely the upregulation of PDAC cell migration and invasion. We showed increased levels of CCL15 transcripts and protein expressions in human PDAC tissue samples, as well as in cultured cell lines. Furthermore, PDAC cells also expressed CCL15 receptors, including CCR1 and CCR3. Murine PDAC cell lines and tissues strengthened this finding. The manipulation of CCL15 in metastatic Panc-1 cells through CCL15 knockdown or CCL15 neutralization decreased Panc-1 cell motility and invasiveness. In addition, treating non-metastatic BxPC-3 cells with recombinant CCL15 accelerated the cell migration of BxPC-3. A reduction in the levels of reactive oxygen species (ROS) by either N-Acetyl-L-Cysteine treatment or p22phox knockdown led to a decrease in Panc-1 cell migration and a reversed effect on recombinant CCL15-promoted BxPC-3 cell movement. Importantly, the knockdown of oncogenic Kras in Panc-1 cells abolished CCL15 protein expression and impeded cell migration without affecting PDAC cell growth. Altogether, our work elucidates an additional molecular pathway of oncogenic Kras to promote PDAC metastasis through the upregulation of cell migration and invasion by the Kras downstream CCL15, a lesser-known cytokine within the cancer research field.

Life Entrapped in a Network of Atavistic Attractors: How to Find a Rescue

In view of unified cell bioenergetics, cell bioenergetic problems related to cell overenergization can cause excessive disturbances in current cell fate and, as a result, lead to a change of cell-fate. At the onset of the problem, cell overenergization of multicellular organisms (especially overenergization of mitochondria) is solved inter alia by activation and then stimulation of the reversible Crabtree effect by cells. Unfortunately, this apparently good solution can also lead to a much bigger problem when, despite the activation of the Crabtree effect, cell overenergization persists for a long time. In such a case, cancer transformation, along with the Warburg effect, may occur to further reduce or stop the charging of mitochondria by high-energy molecules. Understanding the phenomena of cancer transformation and cancer development has become a real challenge for humanity. To date, many models have been developed to understand cancer-related mechanisms. Nowadays, combining all these models into one coherent universal model of cancer transformation and development can be considered a new challenge. In this light, the aim of this article is to present such a potentially universal model supported by a proposed new model of cellular functionality evolution. The methods of fighting cancer resulting from unified cell bioenergetics and the two presented models are also considered.

Redox signaling by glutathione peroxidase 2 links vascular modulation to metabolic plasticity of breast cancer

In search of redox mechanisms in breast cancer, we uncovered a striking role for glutathione peroxidase 2 (GPx2) in oncogenic signaling and patient survival. GPx2 loss stimulates malignant progression due to reactive oxygen species/hypoxia inducible factor-α (HIF1α)/VEGFA (vascular endothelial growth factor A) signaling, causing poor perfusion and hypoxia, which were reversed by GPx2 reexpression or HIF1α inhibition. Ingenuity Pathway Analysis revealed a link between GPx2 loss, tumor angiogenesis, metabolic modulation, and HIF1α signaling. Single-cell RNA analysis and bioenergetic profiling revealed that GPx2 loss stimulated the Warburg effect in most tumor cell subpopulations, except for one cluster, which was capable of oxidative phosphorylation and glycolysis, as confirmed by coexpression of phosphorylated-AMPK and GLUT1. These findings underscore a unique role for redox signaling by GPx2 dysregulation in breast cancer, underlying tumor heterogeneity, leading to metabolic plasticity and malignant progression.

Receptor-Tyrosine Kinase Inhibitor Ponatinib Inhibits Meningioma Growth In Vitro and In Vivo

To date, there is no standard-of-care systemic therapy for the treatment of aggressive meningiomas. Receptor tyrosine kinases (RTK) are frequently expressed in aggressive meningiomas and are associated with poor survival. Ponatinib is a FDA- and EMA-approved RTK inhibitor and its efficacy in meningioma has not been studied so far. Therefore, we investigated ponatinib as a potential drug candidate against meningioma. Cell viability and cell proliferation of ponatinib-treated meningioma cells were assessed using crystal violet assay, manual counting and BrdU assay. Treated meningioma cell lines were subjected to flow cytometry to evaluate the effects on cell cycle and apoptosis. Meningioma-bearing mice were treated with ponatinib to examine antitumor effects in vivo. qPCR was performed to assess the mRNA levels of tyrosine kinase receptors after ponatinib treatment. Full-length cDNA sequencing was carried out to assess differential gene expression. IC50 values of ponatinib were between 171.2 and 341.9 nM in three meningioma cell lines. Ponatinib induced G0/G1 cell cycle arrest and subsequently led to an accumulation of cells in the subG1-phase. A significant induction of apoptosis was observed in vitro. In vivo, ponatinib inhibited meningioma growth by 72.6%. Mechanistically, this was associated with downregulation of PDGFRA/B and FLT3 mRNA levels, and mitochondrial dysfunction. Taken together, ponatinib is a promising candidate for targeted therapy in the treatment of aggressive meningioma.

Continuing regular physical activity and maintaining body weight have a synergistic interaction in improving survival: a population-based cohort study including 6.5 million people

AIMS

Continuing physical activity (PA) and maintaining body weight are tightly intertwined; however, no study investigated whether these two factors have interactions in terms of the mortality. The aim of this study is to elucidate whether continuing regular PA and maintaining body weight have interactions in terms of all-cause mortality risk.

METHODS AND RESULTS

Participants with health screening from both 2009 and 2011 without underlying cancer or cardiovascular disease were included. Physical activity change was grouped as remained active, inactive-to-active, active-to-inactive, or remained inactive. Body weight change was categorized as stable (weight change < 5%), weight gain, or loss. Outcome included all-cause mortality. Of 6 572 984 total participants, 91 347 deaths occurred during a median 7.4-year follow-up. Compared with the remained active and stable weight group, most other groups had a higher mortality risk. The weight loss and remained inactive group [adjusted hazard ratio (aHR), 2.30; 95% confidence interval (CI), 2.22-2.38] and the weight gain and remained inactive group (aHR, 2.17; 95% CI, 2.09-2.25) showed the highest mortality risks. Among stable weight participants, the ranking of the groups from highest to lowest in terms of mortality risk was as follows: remained inactive (aHR, 1.46; 95% CI, 1.41-1.50), active-to-inactive (aHR, 1.24; 95% CI, 1.19-1.29), inactive-to-active (aHR, 1.15; 95% CI, 1.11-1.20), and remained active (reference). Remaining active and maintaining a stable body weight had a synergistic interaction on decreasing all-cause mortality risk (multiplicative P for interaction < 0.001; relative excess risk due to interaction, 0.38; 95% CI, 0.31-0.46; attributable proportion, 0.18; 95% CI, 0.15-0.22).

CONCLUSIONS

Continuing regular PA as recommended and maintaining body weight have multiplicative and additive interactions on reducing all-cause mortality. Healthcare providers should emphasize the importance of both regular PA and body weight maintenance for the general public.

Measurement of Advanced Glycation End Products Could Be Used as an Indicator of Unhealthy Nutrition for Colorectal Cancer Risk

The main culprit behind most cancers is the accumulation of reactive oxygen species. Glyoxal (GO) and methylglyoxal (MGO) are reactive intermediates created by food processing and they are precursors of advanced glycation end products (AGE) that cause glycative stress. We aimed to evaluate the relationship between AGE levels of healthy volunteers and treatment-naive patients diagnosed with colorectal cancer. The study consisted of patients diagnosed with colorectal cancer and healthy volunteers who underwent routine colonoscopy. The study was conducted with a total of 42 cases, 47.6% (n = 20) female. The ages of the participants in the study ranged from 41 to 82 years, and the mean was 60.57 ± 10.78 years. The GO and MGO values of the patient group were found to be significantly higher than those of the control group (p = 0.007, p = 0.001, respectively). The risk of colorectal cancer was 22 and 57 times higher in individuals with GO and MGO values above 1.25 μg/mL and 0.0095 μg/mL, respectively. The blood AGE level is closely related to diet, and it can be decreased through the appropriate improvement of diet. Thus, the measurement of AGE can be used to predict whether a person's nutrition is healthy or unhealthy and prevent increased risk of colorectal cancer.

SLC6A8-mediated intracellular creatine accumulation enhances hypoxic breast cancer cell survival via ameliorating oxidative stress

Background

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, with poor prognosis and limited treatment options. Hypoxia is a key hallmark of TNBC. Metabolic adaptation promotes progression of TNBC cells that are located within the hypoxic tumor regions. However, it is not well understood regarding the precise molecular mechanisms underlying the regulation of metabolic adaptions by hypoxia.

Methods

RNA sequencing was performed to analyze the gene expression profiles in MDA-MB-231 cell line (20% O₂ and 1% O₂). Expressions of Slc6a8, which encodes the creatine transporter protein, were detected in breast cancer cells and tissues by quantitative real-time PCR. Immunohistochemistry was performed to detect SLC6A8 protein abundances in tumor tissues. Clinicopathologic correlation and overall survival were evaluated by chi-square test and Kaplan-Meier analysis, respectively. Cell viability assay and flow cytometry analysis with Annexin V/PI double staining were performed to investigate the impact of SLC6A8-mediated uptake of creatine on viability of hypoxic TNBC cells. TNBC orthotopic mouse model was used to evaluate the effects of creatine in vivo.

Results

SLC6A8 was aberrantly upregulated in TNBC cells in hypoxia. SLC6A8 was drastically overexpressed in TNBC tissues and its level was tightly associated with advanced TNM stage, higher histological grade and worse overall survival of TNBC patients. We found that SLC6A8 was transcriptionally upregulated by p65/NF-κB and mediated accumulation of intracellular creatine in hypoxia. SLC6A8-mediated accumulation of creatine promoted survival and suppressed apoptosis via maintaining redox homeostasis in hypoxic TNBC cells. Furthermore, creatine was required to facilitate tumor growth in xenograft mouse models. Mechanistically, intracellular creatine bolstered cell antioxidant defense by reducing mitochondrial activity and oxygen consumption rates to reduce accumulation of intracellular reactive oxygen species, ultimately activating AKT-ERK signaling, the activation of which protected the viability of hypoxic TNBC cells via mediating the upregulation of Ki-67 and Bcl-2, and the downregulation of Bax and cleaved Caspase-3.

Conclusions

Our study indicates that SLC6A8-mediated creatine accumulation plays an important role in promoting TNBC progression, and may provide a potential therapeutic strategy option for treatment of SLC6A8 high expressed TNBC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01933-7.

The F1Fo-ATPase inhibitor, IF1, is a critical regulator of energy metabolism in cancer cells

In the last two decades, IF1, the endogenous inhibitor of the mitochondrial F1Fo-ATPase (ATP synthase) has assumed greater and ever greater interest since it has been found to be overexpressed in many cancers. At present, several findings indicate that IF1 is capable of playing a central role in cancer cells by promoting metabolic reprogramming, proliferation and resistance to cell death. However, the mechanism(s) at the basis of this pro-oncogenic action of IF1 remains elusive. Here, we recall the main features of the mechanism of the action of IF1 when the ATP synthase works in reverse, and discuss the experimental evidence that support its relevance in cancer cells. In particular, a clear pro-oncogenic action of IF1 is to avoid wasting of ATP when cancer cells are exposed to anoxia or near anoxia conditions, therefore favoring cell survival and tumor growth. However, more recently, various papers have described IF1 as an inhibitor of the ATP synthase when it is working physiologically (i.e. synthethizing ATP), and therefore reprogramming cell metabolism to aerobic glycolysis. In contrast, other studies excluded IF1 as an inhibitor of ATP synthase under normoxia, providing the basis for a hot debate. This review focuses on the role of IF1 as a modulator of the ATP synthase in normoxic cancer cells with the awareness that the knowledge of the molecular action of IF1 on the ATP synthase is crucial in unravelling the molecular mechanism(s) responsible for the pro-oncogenic role of IF1 in cancer and in developing related anticancer strategies.

H2O2 enhances the anticancer activity of TMPyP4 by ROS-mediated mitochondrial dysfunction and DNA damage

Cancer is one of the diseases that threatens human health and is a leading cause of mortality worldwide. High levels of reactive oxygen species (ROS) have been observed in cancer tissues compared with normal tissues in vivo, and it is not yet known how this influences chemotherapeutic drug action. Cationic porphyrin 5,10,15,20-tetra-(N-methyl-4-pyridyl) porphyrin (TMPyP4) is a photosensitizer used in photodynamic therapy (PDT) and a telomerase inhibitor used in the treatment of telomerase-positive cancer. Here, we investigated the anticancer activity of TMPyP4 in A549 and PANC cells cultured in H₂O₂. The results showed that compared to TMPyP4 alone, the combination of TMPyP4 and H₂O₂ exhibited sensitization effects on cell viability and colony formation inhibition and apoptosis in A549 and PANC cells, but had no effect in human normal MIHA cells. Mechanistically, the combination of TMPyP4 and H₂O₂ activates high ROS and mitochondrial membrane potential in A549 and PANC cells, resulting in intense DNA damage and DNA damage responses. Consequently, compared to TMPyP4 alone, TMPyP4 and H₂O₂ combined treatment upregulates the expression of BAX, cleaved caspase 3, and p-JNK and downregulates the expression of Bcl-2 in A549 and PANC cells. Taken together, these data suggested that H₂O₂ enhanced the anticancer activity of TMPyP4-mediated ROS-dependent DNA damage and related apoptotic protein regulation, revealing that the high ROS tumor microenvironment plays an important role in chemotherapeutic drug action.

Mitochondrial STAT3 regulates antioxidant gene expression through complex I-derived NAD in triple negative breast cancer

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor with roles in inflammation and tumorigenicity. A fraction of STAT3 localizes in mitochondria, where it augments tumorigenesis via regulation of mitochondrial functions, including modulation of respiration and redox status. We show a novel mechanism for mitochondrial STAT3 regulation of redox homeostasis in triple‐negative breast cancer cells. Loss of STAT3 diminished complex I dehydrogenase activity and impaired NAD+ regeneration, leading to impaired expression of glutathione biosynthetic genes and other antioxidant genes. Expressing mitochondrially restricted STAT3 or replenishment of the cellular NAD pool restored antioxidant gene expression, as did complementation of the NADH dehydrogenase activity by expression of the STAT3‐independent yeast dehydrogenase, NDI1. These NAD‐regulated processes contributed to malignant phenotypes by promoting clonal cell growth and migration. Proximity interaction and protein pull‐down assays identified three components of complex I that associated with mitochondrial STAT3, providing a potential mechanistic basis for how mitochondrial STAT3 affects complex I activity. Our data document a novel mechanism through which mitochondrial STAT3 indirectly controls antioxidant gene regulation through a retrograde NAD+ signal that is modulated by complex I dehydrogenase activity.

Ozone therapy for the treatment of COVID-19 pneumonia: A scoping review

Severe forms of COVID-19 can evolve into pneumonia, featured by acute respiratory failure due to acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In viral diseases, the replication of viruses is seemingly stimulated by an imbalance between pro-oxidant and antioxidant activity as well as by the deprivation of antioxidant mechanisms. In COVID-19 pneumonia, oxidative stress also appears to be highly detrimental to lung tissues. Although inhaling ozone (O3) gas has been shown to be toxic to the lungs, recent evidence suggests that its administration via appropriate routes and at small doses can paradoxically induce an adaptive reaction capable of decreasing the endogenous oxidative stress. Ozone therapy is recommended to counter the disruptive effects of severe COVID-19 on lung tissues, especially if administered in early stages of the disease, thereby preventing the progression to ARDS.

Association of genetic variants of TMEM135 and PEX5 in the peroxisome pathway with cutaneous melanoma-specific survival

Background

Peroxisomes are ubiquitous and dynamic organelles that are involved in the metabolism of reactive oxygen species (ROS) and lipids. However, whether genetic variants in the peroxisome pathway genes are associated with survival in patients with melanoma has not been established. Therefore, our aim was to identify additional genetic variants in the peroxisome pathway that may provide new prognostic biomarkers for cutaneous melanoma (CM).

Methods

We assessed the associations between 8,397 common single-nucleotide polymorphisms (SNPs) in 88 peroxisome pathway genes and CM disease-specific survival (CMSS) in a two-stage analysis. For the discovery, we extracted the data from a published genome-wide association study from The University of Texas MD Anderson Cancer Center (MDACC). We then replicated the results in another dataset from the Nurse Health Study (NHS)/Health Professionals Follow-up Study (HPFS).

Results

Overall, 95 (11.1%) patients in the MDACC dataset and 48 (11.7%) patients in the NHS/HPFS dataset died of CM. We found 27 significant SNPs in the peroxisome pathway genes to be associated with CMSS in both datasets after multiple comparison correction using the Bayesian false-discovery probability method. In stepwise Cox proportional hazards regression analysis, with adjustment for other covariates and previously published SNPs in the MDACC dataset, we identified 2 independent SNPs (TMEM135 rs567403 C>G and PEX5 rs7969508 A>G) that predicted CMSS (P=0.003 and 0.031, respectively, in an additive genetic model). The expression quantitative trait loci analysis further revealed that the TMEM135 rs567403 GG and PEX5 rs7969508 GG genotypes were associated with increased and decreased levels of mRNA expression of their genes, respectively.

Conclusions

Once our findings are replicated by other investigators, these genetic variants may serve as novel biomarkers for the prediction of survival in patients with CM.

Effects of titanium with different micro/nano structures on the ability of osteoblasts to resist oxidative stress

Excessive accumulation of oxidative intermediates in the elderly significantly aggravates bone degradation and hinders the osseointegration of topological titanium (Ti) implants. Thus, it is of great significance to evaluate the antioxidant and osteoinduction capabilities of various nano, micro or micro/nano-composite structures under oxidative stress (OS) microenvironment. In this study, we discovered that 110 nm titania nanotubes (TNTs) enhanced the adsorption of fibronectin (FN) proteins onto smooth and rough titanium surfaces to varying degrees. Compared with Ti and 30 nm TNTs (T₃₀) groups, cells on 110 nm TNTs (T₁₁₀), microstructure/30 nm TNTs (M₃₀) and microstructure/110 nm TNTs (M₁₁₀) had smaller area, lower reactive oxygen species (ROS), and better proliferation/osteogenic differentiation abilities under OS condition, but there was no significant difference among the three groups. In addition, combined with our previous study, we suggested that T₁₁₀, M₃₀ and M₁₁₀ resistance to OS was also strongly associated with the high expression of FN-receptor integrin α5 or β1. All the findings indicated that the micro/nano-composed structures (M₃₀ & M₁₁₀) had similar anti-oxidation and osteogenesis abilities to T₁₁₀, which provided guidance for the application of different titanium implants with different topologies in the elderly.

Unique Cellular and Biochemical Features of Human Mitochondrial Peroxiredoxin 3 Establish the Molecular Basis for Its Specific Reaction with Thiostrepton

A central hallmark of tumorigenesis is metabolic alterations that increase mitochondrial reactive oxygen species (mROS). In response, cancer cells upregulate their antioxidant capacity and redox-responsive signaling pathways. A promising chemotherapeutic approach is to increase ROS to levels incompatible with tumor cell survival. Mitochondrial peroxiredoxin 3 (PRX3) plays a significant role in detoxifying hydrogen peroxide (H₂O₂). PRX3 is a molecular target of thiostrepton (TS), a natural product and FDA-approved antibiotic. TS inactivates PRX3 by covalently adducting its two catalytic cysteine residues and crosslinking the homodimer. Using cellular models of malignant mesothelioma, we show here that PRX3 expression and mROS levels in cells correlate with sensitivity to TS and that TS reacts selectively with PRX3 relative to other PRX isoforms. Using recombinant PRXs 1–5, we demonstrate that TS preferentially reacts with a reduced thiolate in the PRX3 dimer at mitochondrial pH. We also show that partially oxidized PRX3 fully dissociates to dimers, while partially oxidized PRX1 and PRX2 remain largely decameric. The ability of TS to react with engineered dimers of PRX1 and PRX2 at mitochondrial pH, but inefficiently with wild-type decameric protein at cytoplasmic pH, supports a novel mechanism of action and explains the specificity of TS for PRX3. Thus, the unique structure and propensity of PRX3 to form dimers contribute to its increased sensitivity to TS-mediated inactivation, making PRX3 a promising target for prooxidant cancer therapy.

Synthetic Pesticides and Health in Vulnerable Populations: Agricultural Workers

PURPOSE OF REVIEW

This review aims to summarize epidemiological literature published between May 15, 2018, and May 14, 2019, that examines the relationship between exposure to synthetic pesticides and health of agricultural workers.

RECENT FINDINGS

Current research suggests that exposure to synthetic pesticides may be associated with adverse health outcomes. Agricultural workers represent a potentially vulnerable population, due to a combination of unique social and cultural risk factors as well as exposure to hazards inherent in agricultural work. Pesticide exposure among agricultural workers has been linked to certain cancers, DNA damage, oxidative stress, neurological disorders, and respiratory, metabolic, and thyroid effects. This review describes literature suggesting that agricultural workers exposed to synthetic pesticides are at an increased risk of certain cancers and neurological disorders. Recent research on respiratory effects is sparse, and more research is warranted regarding DNA damage, oxidative stress, metabolic outcomes, and thyroid effects.

Miro1-mediated mitochondrial positioning supports subcellular redox status

Mitochondria are strategically trafficked throughout the cell by the action of microtubule motors, the actin cytoskeleton and adapter proteins. The intracellular positioning of mitochondria supports subcellular levels of ATP, Ca²⁺ and reactive oxygen species (ROS, i.e. hydrogen peroxide, H₂O₂). Previous work from our group showed that deletion of the mitochondrial adapter protein Miro1 leads to perinuclear clustering of mitochondria, leaving the cell periphery devoid of mitochondria which compromises peripheral energy status. Herein, we report that deletion of Miro1 significantly restricts subcellular H₂O₂ levels to the perinuclear space which directly affects intracellular responses to elevated mitochondrial ROS. Using the genetically encoded H₂O₂-responsive fluorescent biosensor HyPer7, we show that the highest levels of subcellular H₂O₂ map to sites of increased mitochondrial density. Deletion of Miro1 or disruption of microtubule dynamics with Taxol significantly reduces peripheral H₂O₂ levels. Following inhibition of mitochondrial complex 1 with rotenone we observe elevated spikes of H₂O₂ in the cell periphery and complementary oxidation of mitochondrial peroxiredoxin 3 (PRX3) and cytosolic peroxiredoxin 2 (PRX2). Conversely, in cells lacking Miro1, rotenone did not increase peripheral H₂O₂ or PRX2 oxidation but rather lead to increased nuclear H₂O₂ and an elevated DNA-damage response. Lastly, local levels of HyPer7 oxidation correlate with the size and abundance of focal adhesions (FAs) in MEFs and cells lacking Miro1 have significantly smaller focal adhesions and reduced phosphorylation levels of vinculin and p130Cas compared to Miro1^+/+ MEFs. Together, we present evidence that the intracellular distribution of mitochondria influences subcellular H₂O₂ levels and local cellular responses dependent on mitochondrial ROS.

Development of Cancer in Patients With Heart Failure: How Systemic Inflammation Can Lay the Groundwork

In the last decade, cardiologists and oncologists have provided clinical and experimental evidence that cancer, and not only chemotherapeutic agents, can cause detrimental effects on heart structure and function, a consequence that has serious clinical implications for patient management. In parallel, the intriguing idea that heart failure (HF) may be an oncogenic condition has also received growing attention. A number of epidemiological and clinical studies have reported that patients with HF have a higher risk of developing cancer. Chronic low-grade systemic inflammation has been proposed as a major pathophysiological process linking the failing heart to the multi-step process of carcinogenesis. According to this view, pro-inflammatory mediators secreted by the damaged heart generate a favorable milieu that promotes tumor development and accelerates malignant transformation. HF-associated inflammation synergizes with tumor-associated inflammation, so that over time it is no longer possible to distinguish the effects of one or the other. Experimental studies have just begun to search for the molecular effectors of this process, with the ultimate goal that of identifying mechanisms suitable for anti-cancer target therapy to reduce the risk of incident cancer in patients already affected by HF. In this review we critically discuss strengths and limitations of clinical and experimental studies that support a causal relationship between HF and cancer, and focus on HF-associated inflammation, cardiokines and their endocrine functions linking one and the other disease.

The multifaceted role of reactive oxygen species in tumorigenesis

Redox homeostasis is an essential requirement of the biological systems for performing various normal cellular functions including cellular growth, differentiation, senescence, survival and aging in humans. The changes in the basal levels of reactive oxygen species (ROS) are detrimental to cells and often lead to several disease conditions including cardiovascular, neurological, diabetes and cancer. During the last two decades, substantial research has been done which clearly suggests that ROS are essential for the initiation, progression, angiogenesis as well as metastasis of cancer in several ways. During the last two decades, the potential of dysregulated ROS to enhance tumor formation through the activation of various oncogenic signaling pathways, DNA mutations, immune escape, tumor microenvironment, metastasis, angiogenesis and extension of telomere has been discovered. At present, surgery followed by chemotherapy and/or radiotherapy is the major therapeutic modality for treating patients with either early or advanced stages of cancer. However, the majority of patients relapse or did not respond to initial treatment. One of the reasons for recurrence/relapse is the altered levels of ROS in tumor cells as well as in cancer-initiating stem cells. One of the critical issues is targeting the intracellular/extracellular ROS for significant antitumor response and relapse-free survival. Indeed, a large number of FDA-approved anticancer drugs are efficient to eliminate cancer cells and drug resistance by increasing ROS production. Thus, the modulation of oxidative stress response might represent a potential approach to eradicate cancer in combination with FDA-approved chemotherapies, radiotherapies as well as immunotherapies.

On the Anti-Cancer Effect of Cold Atmospheric Plasma and the Possible Role of Catalase-Dependent Apoptotic Pathways

Cold atmospheric plasma (CAP) is a promising new agent for (selective) cancer treatment, but the underlying cause of the anti-cancer effect of CAP is not well understood yet. Among different theories and observations, one theory in particular has been postulated in great detail and consists of a very complex network of reactions that are claimed to account for the anti-cancer effect of CAP. Here, the key concept is a reactivation of two specific apoptotic cell signaling pathways through catalase inactivation caused by CAP. Thus, it is postulated that the anti-cancer effect of CAP is due to its ability to inactivate catalase, either directly or indirectly. A theoretical investigation of the proposed theory, especially the role of catalase inactivation, can contribute to the understanding of the underlying cause of the anti-cancer effect of CAP. In the present study, we develop a mathematical model to analyze the proposed catalase-dependent anti-cancer effect of CAP. Our results show that a catalase-dependent reactivation of the two apoptotic pathways of interest is unlikely to contribute to the observed anti-cancer effect of CAP. Thus, we believe that other theories of the underlying cause should be considered and evaluated to gain knowledge about the principles of CAP-induced cancer cell death.

iASPP-Mediated ROS Inhibition Drives 5-Fu Resistance Dependent on Nrf2 Antioxidative Signaling Pathway in Gastric Adenocarcinoma

AIMS

Inhibitor for the apoptosis-stimulating protein of p53 (iASPP) has been reported to be correlated with 5-fluorouracil (5-Fu) resistance in renal cell carcinoma. Here, we uncover mechanisms of iASPP-Nrf2-ROS regulation of 5-Fu resistance which are important for the development of alternative treatment strategies for gastric adenocarcinoma treatment.

METHODS

We analyzed iASPP and Nrf2 through TCGA RNA-seq data, UALCAN analysis, and cBioPortal datasets. Intracellular ROS generation was determined by 2',7'-dichloro-fluorescin diacetate staining. Transwell was used to evaluate the invasion. The expression of iASPP, Nrf2, HO-1, and GSTP1 was tested using western blot.

RESULTS

We found that iASPP KD led to an apparent 5-Fu-induced ROS accumulation in MGC803 and SCG790 cells. Accompanied by iASPP KD, Nrf2 was markedly decreased. iASPP-induced ROS inhibition relies on Nrf2, and due to both knocked down iASPP and Nrf2, the level of ROS did not show an obvious difference with Nrf2 KD solely. Similarly, iASPP KD failed to enhance the Nrf2 KD-mediated ROS accumulation after 5-Fu treatment, suggesting that iASPP-induced antioxidative effects related to 5-Fu resistance are partially dependent on Nrf2. Also, the combination of iASPP KD and Nrf2 KD did not show any synergistic effect on apoptosis after 5-Fu treatment in MGC803 and SCG790 cells. Further studies revealed that iASPP KD or Nrf2 KD could decrease the expression of HO-1 and GSTP1.

CONCLUSIONS

Our data highlight that iASPP plays a crucial role in the inhibition of 5-Fu-induced apoptosis resistance by removing ROS accumulation in gastric adenocarcinoma, and that the removal of ROS induced by iASPP is Nrf2 signaling dependent.

p53 isoform Δ113p53 promotes zebrafish heart regeneration by maintaining redox homeostasis

Neonatal mice and adult zebrafish can fully regenerate their hearts through proliferation of pre-existing cardiomyocytes. Previous studies have revealed that p53 signalling is activated during cardiac regeneration in neonatal mice and that hydrogen peroxide (H₂O₂) generated near the wound site acts as a novel signal to promote zebrafish heart regeneration. We recently demonstrated that the expression of the p53 isoform Δ133p53 is highly induced upon stimulation by low-level reactive oxygen species (ROS) and that Δ133p53 coordinates with full-length p53 to promote cell survival by enhancing the expression of antioxidant genes. However, the function of p53 signalling in heart regeneration remains uncharacterised. Here, we found that the expression of Δ113p53 is activated in cardiomyocytes at the resection site in the zebrafish heart in a full-length p53- and ROS signalling-dependent manner. Cell lineage tracing showed that Δ113p53-positive cardiomyocytes undergo cell proliferation and contribute to myocardial regeneration. More importantly, heart regeneration is impaired in Δ113p53^M/M mutant zebrafish. Depletion of Δ113p53 significantly decreases the proliferation frequency of cardiomyocytes but has little effect on the activation of gata4-positive cells, their migration to the edge of the wound site, or apoptotic activity. Live imaging of intact hearts showed that induction of H₂O₂ at the resection site is significantly higher in Δ113p53^M/M mutants than in wild-type zebrafish, which may be the result of reduced induction of antioxidant genes in Δ113p53^M/M mutants. Our findings demonstrate that induction of Δ113p53 in cardiomyocytes at the resection site functions to promote heart regeneration by increasing the expression of antioxidant genes to maintain redox homeostasis.

Recent Advances in Nanostrategies Capable of Overcoming Biological Barriers for Tumor Management

Engineered nanomaterials have been extensively employed as therapeutics for tumor management. Meanwhile, the complex tumor niche along with multiple barriers at the cellular level collectively hinders the action of nanomedicines. Here, the advanced strategies that hold promise for overcoming the numerous biological barriers facing nanomedicines are summarized. Starting from tumor entry, methods that promote tissue penetration of nanomedicine and address the hypoxia issue are also highlighted. Then, emphasis is given to the significance of overcoming both physical barriers, such as membrane-associated efflux pumps, and biological features, such as resistance to apoptosis. The pros and cons for an individual approach are presented. In addition, the associated technical problems are discussed, along with the importance of balancing the therapeutic merits and the additional cost of sophisticated nanomedicine designs.

Lung cancer increases H2O2 concentration in the exhaled breath condensate, extent of mtDNA damage, and mtDNA copy number in buccal mucosa

We have shown that the H2O2 concentration in exhaled breath condensate (EBC) in lung cancer patients increases significantly compared to the EBC of healthy people and revealed the correlation between the H2O2 level in the EBC and amount of mtDNA damage in buccal mucosa cells. The H2O2 hyper-production may trigger mitochondrial biogenesis, thereby resulting in an increase in mtDNA copy number. However, we did not observe a significant difference in the studied parameters between smokers and non-smokers. Overall, our data suggest that H2O2 concentration in the EBC, the extent of mtDNA damage, and mtDNA copy number in buccal mucosa could be potential as an early diagnostic marker of lung cancer.

Dose-dependent regulation of mitochondrial function and cell death pathway by sorafenib in liver cancer cells

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and the fourth most frequent cause of cancer-related death worldwide. Sorafenib is the first line recommended therapy for patients with locally advanced/metastatic HCC. The low response rate is attributed to intrinsic resistance of HCC cells to Sorafenib. The potential resistance to Sorafenib-induced cell death is multifactorial and involves all hallmarks of cancer. However, the presence of sub-therapeutic dose can negatively influence the antitumoral properties of the drug. In this sense, the present study showed that the sub-optimal Sorafenib concentration (10 nM) was associated with activation of caspase-9, AMP-activated protein kinase (AMPK), sustained autophagy, peroxisome proliferator-activated receptor-coactivator 1α (PGC-1α) and mitochondrial function in HepG2 cells. The increased mitochondrial respiration by Sorafenib (10 nM) was also observed in permeabilized HepG2 cells, but not in isolated rat mitochondria, which suggests the involvement of an upstream component in this regulatory mechanism. The basal glycolysis was dose dependently increased at early time point studied (6 h). Interestingly, Sorafenib increased nitric oxide (NO) generation that played an inhibitory role in mitochondrial respiration in sub-therapeutic dose of Sorafenib. The administration of sustained therapeutic dose of Sorafenib (10 µM, 24 h) induced mitochondrial dysfunction and dropped basal glycolysis derived acidification, as well as increased oxidative stress and apoptosis in HepG2. In conclusion, the accurate control of the administered dose of Sorafenib is relevant for the potential prosurvival or proapoptotic properties induced by the drug in liver cancer cells.

Integrated molecular signaling involving mitochondrial dysfunction and alteration of cell metabolism induced by tyrosine kinase inhibitors in cancer

Cancer cells have unlimited replicative potential, insensitivity to growth-inhibitory signals, evasion of apoptosis, cellular stress, and sustained angiogenesis, invasiveness and metastatic potential. Cancer cells adequately adapt cell metabolism and integrate several intracellular and redox signaling to promote cell survival in an inflammatory and hypoxic microenvironment in order to maintain/expand tumor phenotype. The administration of tyrosine kinase inhibitor (TKI) constitutes the recommended therapeutic strategy in different malignancies at advanced stages.

There are important interrelationships between cell stress, redox status, mitochondrial function, metabolism and cellular signaling pathways leading to cell survival/death. The induction of apoptosis and cell cycle arrest widely related to the antitumoral properties of TKIs result from tightly controlled events involving different cellular compartments and signaling pathways. The aim of the present review is to update the most relevant studies dealing with the impact of TKI treatment on cell function. The induction of endoplasmic reticulum (ER) stress and Ca²⁺ disturbances, leading to alteration of mitochondrial function, redox status and phosphatidylinositol 3-kinase (PI3K)-protein kinase B (Akt)-mammalian target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK) signaling pathways that involve cell metabolism reprogramming in cancer cells will be covered. Emphasis will be given to studies that identify key components of the integrated molecular pattern including receptor tyrosine kinase (RTK) downstream signaling, cell death and mitochondria-related events that appear to be involved in the resistance of cancer cells to TKI treatments.

Iodine‑125 seed radiation induces ROS‑mediated apoptosis, autophagy and paraptosis in human esophageal squamous cell carcinoma cells

Iodine-125 (¹²⁵I) seed brachytherapy has been proven to be a safe and effective treatment for advanced esophageal cancer; however, the mechanisms underlying its actions are not completely understood. In the present study, the anti-cancer mechanisms of ¹²⁵I seed radiation in human esophageal squamous cell carcinoma (ESCC) cells (Eca-109 and KYSE-150) were determined, with a particular focus on the mode of cell death. The results showed that ¹²⁵I seed radiation significantly inhibited cell proliferation, and induced DNA damage and G2/M cell cycle arrest in both ESCC cell lines. ¹²⁵I seed radiation induced cell death through both apoptosis and paraptosis. Eca-109 cells were primarily killed by inducing caspase-dependent apoptosis, with 6 Gy radiation resulting in the largest response. KYSE-150 cells were primarily killed by inducing paraptosis, which is characterized by extensive cytoplasmic vacuolation. ¹²⁵I seed radiation induced autophagic flux in both ESCC cell lines, and autophagy inhibition by 3-methyladenine enhanced radiosensitivity. Furthermore ¹²⁵I seed radiation induced increased production of reactive oxygen species (ROS) in both ESCC cell lines. Treatment with an ROS scavenger significantly attenuated the effects of ¹²⁵I seed radiation on endoplasmic reticulum stress, autophagy, apoptosis, paraptotic vacuoles and reduced cell viability. In vivo experiments showed that ¹²⁵I seed brachytherapy induced ROS generation, initiated cell apoptosis and potential paraptosis, and inhibited cell proliferation and tumor growth. In summary, the results demonstrate that in ESCC cells, ¹²⁵I seed radiation induces cell death through both apoptosis and paraptosis; and at the same time initiates protective autophagy. Additionally, ¹²⁵I seed radiation-induced apoptosis, paraptosis and autophagy was considerably mediated by ROS.

Antioxidant Properties and Redox-Modulating Activity of Chitosan and Its Derivatives: Biomaterials with Application in Cancer Therapy

Many studies have shown that mitochondrial metabolism has a fundamental role in induction of carcinogenesis due to the influence of increased levels of reactive oxygen species (ROS) generation in all steps of oncogene transformation and cancer progression. It is widely accepted that the anticancer effect of conventional anticancer drugs is due to induction of oxidative stress and elevated intracellular levels of ROS, which alter the redox homeostasis of cancer cells. On the other hand, the harmful side effects of conventional anticancer chemotherapeutics are also due to increased production of ROS and disruption of redox homeostasis of normal cells and tissues. Therefore, there is a growing interest toward the development of natural antioxidant compounds from various sources, which could impact the redox state of cancer and normal cells by different pathways and could prevent damage from oxidant-mediated reactions. It is known that chitosan exhibits versatile biological properties, including biodegradability, biocompatibility, and a less toxic nature. Because of its antioxidant, antibacterial, anticancer, anti-inflammatory, and immunostimulatory activities, the biopolymer has been used in a wide variety of pharmaceutical, biomedical, food industry, health, and agricultural applications and has been classified as a new physiologically bioactive material.

Finding an efficient tetramethylated hydroxydiethylene of resveratrol analogue for potential anticancer agent

With the improvement and advance in cancer diagnosis and treatment, the cancer is still a major cause of morbidity and mortality throughout the world. Obviously, new breakthroughs in therapies remain be urgent needed. In this work, we designed and synthesized the compound 1-4, namely resveratrol analogues with methylation of hydroxy distyrene, to further explore its new anti-cancer potential. Encouragingly, compound 1 ((E)-4,4'-(ethene-1,2-diyl)bis(3,5-dimethylphenol)) exhibited cytotoxicity superior to resveratrol in MCF 7 cells. More importantly, the compound 1 showed greater toxicity to tumor cells than that to normal cells, which proved that it could selectively kill tumor cells. The favorable results encouraged us to explore the inhibitory mechanism of compound 1 on MCF 7 cells. The research finding indicated the compound 1 inhibited tumor cell proliferation by both arresting cell cycle in S phase and apoptosis via a prooxidant manner. In addition, the results further verified compound 1 caused cell cycle arrest in S phase and apoptosis by down-regulation of the cycling A1/cycling A2 expression and the rise of Bax/Bcl-2 ratio in a p21-dependant pathway in MCF 7 cells. Therefore, these results are helpful for the effective design of anticancer reagents and the better understanding of their mechanism of action.