Selective killing of gastric cancer cells by a small molecule via targeting TrxR1 and ROS-mediated ER stress activation

Exploring the therapeutic potential of diterpenes in gastric cancer: Mechanisms, efficacy, and clinical prospects

Gastric cancer (GC) remains a significant global health challenge, particularly prevalent in East Asia. Despite advancements in various treatment modalities, the prognosis for patients, especially those in advanced stages, remains poor, highlighting the need for innovative therapeutic approaches. This review explores the promising potential of diterpenes, naturally occurring compounds with robust anticancer properties, derived from diverse sources such as plants, marine organisms, and fungi. Diterpenes have shown the ability to influence reactive oxygen species (ROS) generation, ferroptosis, and autophagy, positioning them as attractive candidates for novel cancer therapies. This review explores the mechanisms of action of diterpenes and their clinical implications for the treatment of GC. Additionally, it addresses the challenges in translating these compounds from preclinical studies to clinical applications, emphasizing the need for further research to enhance their therapeutic profiles and minimize potential side effects. The discussion underscores the importance of diterpenes in future anticancer strategies, particularly in the fight against gastric cancer.

Small-molecule redox modulators with anticancer activity: A comprehensive mechanistic update

The pursuit of effective anticancer therapies has led to a burgeoning interest in the realm of redox modulation. This review provides a comprehensive exploration of the intricate mechanisms by which diverse anticancer molecules leverage redox pathways for therapeutic intervention. Redox modulation, encompassing the fine balance of oxidation-reduction processes within cells, has emerged as a pivotal player in cancer treatment. This review delves into the multifaceted mechanisms of action employed by various anticancer compounds, including small molecules and natural products, to disrupt cancer cell proliferation and survival. Beginning with an examination of the role of redox signaling in cancer development and resistance, the review highlights how aberrant redox dynamics can fuel tumorigenesis. It then meticulously dissects the strategies employed by anticancer agents to induce oxidative stress, perturb redox equilibrium, and trigger apoptosis within cancer cells. Furthermore, the review explores the challenges and potential side effects associated with redox-based treatments, along with the development of novel redox-targeted agents. In summary, this review offers a profound understanding of the dynamic interplay between redox modulation and anticancer molecules, presenting promising avenues to revolutionize cancer therapy and enhance patient outcomes.

Rifampicin-induced ER stress and excessive cytoplasmic vacuolization instigate hepatotoxicity via alternate programmed cell death paraptosis in vitro and in vivo

AIMS

Rifampicin-induced hepatotoxicity is a primary cause of drug-induced liver injury (DILI), posing a significant challenge to its continued clinical application. Moreover, the mechanism underlying rifampicin-induced hepatotoxicity remains unclear.

MAIN METHODS

Human hepatocyte line-17 (HHL-17) cells were treated with an increasing dose of rifampicin for 24 h, and male Wistar rats were given rifampicin [150 mg/kg body weight (bw)] orally for 28 days. Viability assay, protein expression, and cell death assays were analyzed in vitro. Moreover, liver serum markers, body/organ weight, H&E staining, protein expression, etc., were assayed in vivo.

KEY FINDINGS

Rifampicin induced a dose-dependent hepatotoxicity in HHL-17 cells (IC50; 600 μM), and increased the serum levels of liver injury markers, e.g., alanine transaminase (ALT) and aspartate transaminase (AST) in rats. Rifampicin-induced cell death was non-apoptotic and non-necroptotic both in vitro and in vivo. Further, excessive cellular vacuolization and reduced expression of Alix protein confirmed the induction of paraptosis both in vitro and in vivo. In addition, a significant increase in the endoplasmic reticulum (ER) stress markers (e.g., BiP, CHOP, and total polyubiquitinated proteins) was detected, demonstrating the induction of ER stress and altered protein homeostasis. Interestingly, rifampicin-induced hepatotoxicity was associated with the inhibition of autophagy and enhanced reactive oxygen species (ROS) generation in HHL-17 cells. Furthermore, inhibition of protein synthesis by cycloheximide (CHX) suppressed paraptosis by alleviating rifampicin-induced ER stress and ROS generation.

SIGNIFICANCE

Rifampicin-induced hepatotoxicity involves ER stress-driven paraptosis as a novel mechanism of its toxicity that may be targeted to protect liver cells from rifampicin toxicity.

Nanotechnology and curcumin: a novel and promising approach in digestive cancer therapy

This study reviews the application of nanotechnology and curcumin, a polyphenol extracted from turmeric, in treating digestive cancers, one of the most common types of malignancies worldwide. Despite curcumin's potential for inhibiting tumor growth, its clinical application is hindered by issues such as poor solubility and bioavailability. Nanomedicine, with its unique ability to enhance drug delivery and reduce toxicity, offers a solution to these limitations. The paper focuses on the development of nanoformulations of curcumin, such as nanoparticles and liposomes, that improve its bioavailability and efficacy in treating digestive cancers, including liver and colorectal cancers. The study serves as a valuable reference for future research and development in this promising therapeutic approach.

Diffractaic acid exhibits thioredoxin reductase 1 inhibition in lung cancer A549 cells

Lung cancer is the leading cause of cancer-related deaths all over the world. Therefore, it has gained importance in the development of new chemotherapeutic strategies to identify anticancer agents with low side effects, reliable, high anticancer potential, and specific to lung cancer cells. Thioredoxin reductase 1 (TrxR1) is an important therapeutic target for lung cancer treatment because of its overexpression in tumor cells. Here, we aimed to examine the anticancer effect of diffractaic acid, a lichen secondary metabolite, in A549 cells by comparing it with the commercial chemotherapeutic drug carboplatin and also to investigate whether the anticancer effect of diffractaic acid occurs via TrxR1-targeting. The IC50 value of diffractaic acid on A549 cells was determined as 46.37 μg/mL at 48 h, and diffractaic acid had stronger cytotoxicity than carboplatin in A549 cells. qPCR results revealed that diffractaic acid promoted the intrinsic apoptotic pathway through the upregulation of the BAX/BCL2 ratio and P53 gene in A549 cells, which is consistent with the flow cytometry results. Furthermore, migration analysis results indicated that diffractaic acid impressively suppressed the migration of A549 cells. While the enzymatic activity of TrxR1 was inhibited by diffractaic acid in A549 cells, no changes were seen in the quantitative expression levels of gene and protein. These findings provide fundamental data on the anticancer effect of diffractaic acid on A549 cells targeting TrxR1 activity, suggesting that it could be considered a chemotherapeutic agent for lung cancer therapy.

Identification of altered metabolic functional components using metabolomics to analyze the different ages of fruiting bodies of Sanghuangporus vaninii cultivated on cut log substrates

Sanghuangporus vaninii is a profitable traditional and medicinal edible fungus with uncommon therapeutic properties and medicinal value. The accumulation of active ingredients in this fungus that is used in traditional Chinese medicine is affected by its years of growth, and their pharmacological activities are also affected. However, the effects of age on the medicinal value of fruiting bodies of S. vaninii cultivated on cut log substrate remain unclear. In this study, an untargeted liquid chromatography mass spectrometry (LC-MS)-based metabolomics approach was performed to characterize the profiles of metabolites from 1-, 2- and 3-year-old fruiting bodies of S. vaninii. A total of, 156 differentially accumulated metabolites (DAMs) were screened based on the criterion of a variable importance projection greater than 1.0 and p < 0.01, including 75% up regulated and 25% down regulated. The results of enrichment of metabolic pathways showed that the metabolites involved the biosynthesis of plant secondary metabolites, biosynthesis of amino acids, central carbon metabolism in cancer, steroid hormone biosynthesis, linoleic acid metabolism, prolactin signaling pathway, and arginine biosynthesis, and so on. The biosynthesis of plant secondary metabolites pathway was significantly activated. Five metabolites were significantly elevated within the growth of fruiting bodies, including 15-keto-prostaglandin F2a, (4S, 5R)-4,5,6-trihydroxy-2-iminohexanoate, adenylsuccinic acid, piplartine, and chenodeoxycholic acid. 15-keto-prostaglandin F2a is related to the pathway of arachidonic acid metabolism and was significantly increased up to 1,320- and 535-fold in the 2- and 3-year-old fruiting bodies, respectively, compared with those in the 1-year-old group. The presence of these bioactive natural products in S. vaninii is consistent with the traditional use of Sanghuang, which prompted an exploration of its use as a source of natural prostaglandin in the form of foods and nutraceuticals. These findings may provide insight into the functional components of S. vaninii to develop therapeutic strategies.

Cancer Metabolism: The Role of ROS in DNA Damage and Induction of Apoptosis in Cancer Cells

Cancer is a huge challenge for people worldwide. High reactive oxygen species (ROS) levels are a recognized hallmark of cancer and an important aspect of cancer treatment research. Abnormally elevated ROS levels are often attributable to alterations in cellular metabolic activities and increased oxidative stress, which affects both the development and maintenance of cancer. Moderately high levels of ROS are beneficial to maintain tumor cell genesis and development, while toxic levels of ROS have been shown to be an important force in destroying cancer cells. ROS has become an important anticancer target based on the proapoptotic effect of toxic levels of ROS. Therefore, this review summarizes the role of increased ROS in DNA damage and the apoptosis of cancer cells caused by changes in cancer cell metabolism, as well as various anticancer therapies targeting ROS generation, in order to provide references for cancer therapies based on ROS generation.

Therapeutic potential of curcumin and its nanoformulations for treating oral cancer

The global incidence of oral cancer has steadily increased in recent years and is associated with high morbidity and mortality. Oral cancer is the most common cancer in the head and neck region, and is predominantly of epithelial origin (i.e. squamous cell carcinoma). Oral cancer treatment modalities mainly include surgery with or without radiotherapy and chemotherapy. Though proven effective, chemotherapy has significant adverse effects with possibilities of tumor resistance to anticancer drugs and recurrence. Thus, there is an imperative need to identify suitable anticancer therapies that are highly precise with minimal side effects and to make oral cancer treatment effective and safer. Among the available adjuvant therapies is curcumin, a plant polyphenol isolated from the rhizome of the turmeric plant Curcuma longa. Curcumin has been demonstrated to have anti-infectious, antioxidant, anti-inflammatory, and anticarcinogenic properties. Curcumin has poor bioavailability, which has been overcome by its various analogues and nanoformulations, such as nanoparticles, liposome complexes, micelles, and phospholipid complexes. Studies have shown that the anticancer effects of curcumin are mediated by its action on multiple molecular targets, including activator protein 1, protein kinase B (Akt), nuclear factor κ-light-chain-enhancer of activated B cells, mitogen-activated protein kinase, epidermal growth factor receptor (EGFR) expression, and EGFR downstream signaling pathways. These targets play important roles in oral cancer pathogenesis, thereby making curcumin a promising adjuvant treatment modality. This review aims to summarize the different novel formulations of curcumin and their role in the treatment of oral cancer.

Beta-catenin knockdown impairs the viability of ovarian cancer cells by modulating YAP-dependent glycolysis

OBJECTIVES

Ovarian cancer (OC) ranks fifth among the main causes of cancer-related deaths in women worldwide. PCLAF/KIAA0101 and Yes-associated protein (YAP) have been linked to several human malignant cancers, including OC. However, the roles of KIAA0101 and YAP in glycolysis-dependent OC cell proliferation remain unknown.

METHODS

qRT-PCR and western blot were performed to analyze the KIAA0101 expression. Short hairpin RNA transfection was performed to silence KIAA0101 expression in cells. Cell viability and apoptosis were assayed by colony formation and flow cytometry, respectively. Glucose uptake, lactate production, and glycolytic enzyme expression were assessed to determine the level of cellular glycolysis. Phosphorylation and the nuclear localization of YAP were assessed to determine YAP activation.

RESULTS

OC tissue and cell lines exhibited higher KIAA0101 expression than the non-cancerous tissues and cells. KIAA0101 silencing reduced the proliferation and increased the apoptosis of both A2780 and ES-2 OC cell lines. Furthermore, KIAA0101 depletion suppressed glycolysis and YAP activation, as evidenced by increased YAP phosphorylation and decreased nuclear localization. Reactivation of YAP was performed by administration of mitochonic acid 5 in both OC cell lines with KIAA0101 knockdown. Glucose uptake, lactate production, phosphofructokinase, pyruvate dehydrogenase beta, pyruvate kinase M2, triosephosphate isomerase 1, glucose-6-phosphate dehydrogenase, enolase 1, and lactate dehydrogenase expression levels in cells recovered after the reactivation of YAP. Additionally, YAP reactivation increased cell proliferation and inhibited apoptosis.

CONCLUSIONS

This study showed that KIAA0101 could promote glycolysis during nasopharyngeal carcinoma development through YAP signaling activation, suggesting that KIAA0101 could serve as a target for OC treatment.

Anti-Cancer Activity of Gedunin by Induction of Apoptosis in Human Gastric Cancer AGS Cells

Currently, gastric cancer is considered one of the major causes of high mortality and morbidity worldwide. Recent advances in therapeutics, clinical treatment, staging procedures, and imaging techniques are high, yet the prevalence of gastric cancer has not been reduced. Usage of the synthetic drug has many side effects that can lead to other ailments. Gedunin, a phytochemical derived from Azadirachta indica (neem tree), exhibits several pharmacological activities including antitumor, anti-inflammatory, antiulcer, antipyretics, antibacterial, antifungal, anti-diabetic, and antimalarial properties. In the current investigation, the effect of gedunin on the cell viability; reactive oxygen species (ROS) generation by DCFH-DA staining; mitochondrial membrane potential (MMP) by Rh-123 staining; apoptosis by AO/EtBr staining; cell migration and wound healing ability by wound scratch assay; and Bcl-2, Bax, caspase-3, and caspase-9 by ELISA techniques were analyzed in the AGS cells. The treatment with gedunin effectively inhibited the cell viability with IC₅₀ = 20µM, increased the ROS generation, and triggered the apoptosis in AGS cells. The gedunin-treated AGS cells also demonstrated a decreased MMP status. The increment in the ROS generation leads to oxidative stress which in turn induce the apoptosis. The activity of Bax gene was upregulated and the activity of Bcl-2 gene was down-regulated in the AGS cells after the treatment with gedunin. In the AGS cells treated with gedunin, the caspase-3 and caspase-9 activities were increased. In overall, these findings suggested that gedunin can be used as a potent chemotherapeutic agent in the future to treat gastric cancer.

The Interplay of the Unfolded Protein Response in Neurodegenerative Diseases: A Therapeutic Role of Curcumin

Abnormal accumulation of misfolded proteins in the endoplasmic reticulum and their aggregation causes inflammation and endoplasmic reticulum stress. This promotes accumulation of toxic proteins in the body tissues especially brain leading to manifestation of neurodegenerative diseases. The studies suggest that deregulation of proteostasis, particularly aberrant unfolded protein response (UPR) signaling, may be a common morbific process in the development of neurodegeneration. Curcumin, the mixture of low molecular weight polyphenolic compounds from turmeric, Curcuma longa has shown promising response to prevents many diseases including current global severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and neurodegenerative disorders. The UPR which correlates positively with neurodegenerative disorders were found affected by curcumin. In this review, we examine the evidence from many model systems illustrating how curcumin interacts with UPR and slows down the development of various neurodegenerative disorders (ND), e.g., Alzheimer's and Parkinson's diseases. The recent global increase in ND patients indicates that researchers and practitioners will need to develop a new pharmacological drug or treatment to manage and cure these neurodegenerative diseases.

Antimetastatic Effects of Curcumin in Oral and Gastrointestinal Cancers

Gastrointestinal (GI) cancers are known as frequently occurred solid malignant tumors that can cause the high rate mortality in the world. Metastasis is a significant destructive feature of tumoral cells, which directly correlates with decreased prognosis and survival. Curcumin, which is found in turmeric, has been identified as a potent therapeutic natural bioactive compound (Curcuma longa). It has been traditionally applied for centuries to treat different diseases, and it has shown efficacy for its anticancer properties. Numerous studies have revealed that curcumin inhibits migration and metastasis of GI cancer cells by modulating various genes and proteins, i.e., growth factors, inflammatory cytokines and their receptors, different types of enzymes, caspases, cell adhesion molecules, and cell cycle proteins. Herein, we summarized the antimetastatic effects of curcumin in GI cancers, including pancreatic cancer, gastric cancer, colorectal cancer, oral cancer, and esophageal cancer.

Perspectives for synthetic curcumins in chemoprevention and treatment of cancer: An update with promising analogues

Curcumin, a pure compound extracted from the flowering plant, turmeric (Curcuma longa. Zingiberaceae), is a common dietary ingredient found in curry powder. It has been studied extensively for its anti-inflammatory, antioxidant, antimicrobial and anti-tumour activities. Evidence is accumulating demonstrating its potential in chemoprevention and as an anti-tumour agent for the treatment of cancer. Despite demonstrated safety and tolerability, the clinical application of curcumin is frustrated by its poor solubility, metabolic instability and low oral bioavailability. Consequently researchers have tried novel techniques of formulation and delivery as well as synthesis of analogues with enhanced properties to overcome these barriers. This review presents the synthetic analogues of curcumin that have proven their anticancer potential from different studies. It also highlights studies that combined these analogues with approved chemotherapies and delivered them via novel techniques. Currently, there are no reports of clinical studies on any of the synthetic congeners of curcumin and this presents an opportunity for future research. This review presents the synthetic analogues of curcumin and makes a compelling argument for their potential application in the management of cancerous disease.

Therapeutic potential of curcumin in diabetic retinopathy (Review)

Diabetic retinopathy (DR) is a type of retinal microangiopathy caused by diabetes mellitus. It has become the leading cause of blindness among working individuals worldwide. DR is becoming increasingly common among younger diabetic patients and there is a need for lifelong treatment. The pathogenic mechanisms of DR are influenced by a number of factors, such as hyperglycemia, hyperlipidemia, inflammatory response and oxidative stress, among others. Currently, the treatment methods for DR mainly include retinal photocoagulation, vitrectomy, or anti‑vascular endothelial growth factor (VEGF) therapy. However, these methods have some disadvantages and limitations. Therefore, it is a matter of great interest and urgency to discover drugs that can target the pathogenesis of DR. Since ancient times, traditional Chinese medicine practitioners have accumulated extensive experiences in the use of Chinese herbal medicine for the prevention and treatment of diseases. In the theory of traditional Chinese medicine, curcumin has the effects of promoting blood circulation and relieving pain. A number of studies have also demonstrated that curcumin has multiple biological activities, including exerting anti‑apoptotic, anti‑inflammatory, antioxidant and antitumor properties. In recent years, studies have also confirmed that curcumin can prevent a variety of diabetic complications, including diabetic nephropathy (DN). However, the preventive and curative effects of curcumin on DR and its mechanisms of action have not yet been fully elucidated. The present review aimed to explore the therapeutic potential of curcumin in diabetes mellitus and DR.

The Thioredoxin System: A Promising Target for Cancer Drug Development

The thioredoxin system is highly conserved system found in all living cells and comprises NADPH, thioredoxin, and thioredoxin reductase. This system plays a critical role in preserving a reduced intracellular environment, and its involvement in regulating a wide range of cellular functions makes it especially vital to cellular homeostasis. Its critical role is not limited to healthy cells, it is also involved in cancer development, and is overexpressed in many cancers. This makes the thioredoxin system a promising target for cancer drug development. As such, over the last decade, many inhibitors have been developed that target the thioredoxin system, most of which are small molecules targeting the thioredoxin reductase C-terminal redox center. A few inhibitors of thioredoxin have also been developed. We believe that more efforts should be invested in developing protein/peptide-based inhibitors against both thioredoxin reductase and/or thioredoxin.

Design, synthesis and bioactivity evaluation of coumarin-chalcone hybrids as potential anticancer agents

The selenoprotein thioredoxin reductases (TrxRs) have been extensively studied as a potential target for the development of anticancer drugs. Herein, we designed, synthesized, and evaluated a series of coumarin-chalcone hybrids as TrxR inhibitors. Most of them exhibited enhancing anticancer activity than Xanthohumol (Xn). The representative Xn-2 (IC₅₀ = 3.6 μM) was a fluorescence agent, wherein drug uptake can be readily monitored in living cells by red fluorescence imaging. Xn-2 down-regulated the expression of TrxR, remarkedly induced ROS accumulation to activate mitochondrial apoptosis pathway. Furthermore, Xn-2 inhibited cancer cell metastasis and abolished the colony formation ability of cancer cells. Taken together, these results highlight that compound Xn-2 may be a promising theranostic TrxR inhibitor for human cancer therapy.

Strategy for improved therapeutic efficiency of curcumin in the treatment of gastric cancer

Gastric cancer is a common oncological disease. Although enormous efforts have been expended, possible therapeutic modalities are still limited. For this reason, new therapeutic approaches and agents are highly requested and intensively developed. One strategy is the application of natural agents, such as curcumin, with proven anticancer effects and low toxicity for patients. Therefore, this review discusses the potential application of curcumin in the therapy of gastric cancer and its potential incorporation in therapeutic regimens. Because one of the largest impediments for widespread curcumin application is its limited bioavailability (caused mainly by its very low water solubility), studied strategies (drug delivery systems and curcumin derivatization) aimed to solve this obstacle are discussed in more detail.

Apoptotic Pathway as the Therapeutic Target for Anticancer Traditional Chinese Medicines

Cancer is a leading cause of morbidity and mortality worldwide. Apoptosis is a process of programmed cell death and it plays a vital role in human development and tissue homeostasis. Mounting evidence indicates that apoptosis is closely related to the survival of cancer and it has emerged as a key target for the discovery and development of novel anticancer drugs. Various studies indicate that targeting the apoptotic signaling pathway by anticancer drugs is an important mechanism in cancer therapy. Therefore, numerous novel anticancer agents have been discovered and developed from traditional Chinese medicines (TCMs) by targeting the cellular apoptotic pathway of cancer cells and shown clinically beneficial effects in cancer therapy. This review aims to provide a comprehensive discussion for the role, pharmacology, related biology, and possible mechanism(s) of a number of important anticancer TCMs and their derivatives mainly targeting the cellular apoptotic pathway. It may have important clinical implications in cancer therapy.

Endoplasmic reticulum proteostasis control and gastric cancer

The endoplasmic reticulum (ER) is the primary organelle responsible for the synthesis, modification, folding and secretion of proteins, especially in specialized secretory cells. It also contributes to the maintenance of cellular functions, such as Ca²⁺ storage, lipogenesis, gluconeogenesis, and organelle biogenesis. Cellular stress conditions, such as glucose deprivation, hypoxia and disturbance of Ca²⁺ homeostasis, may increase the risk of protein misfolding and perturb proteostasis. This activates ER stress and triggers the unfolded protein response (UPR), leading to either the restoration of homeostasis or cell death. ER stress and UPR have been shown to play crucial roles in the pathogenesis, progression and treatment response of various cancers. In gastric cancer (GC), one of the most aggressive cancer types, critical functions of ER stress signaling have also started to emerge. Herein, we summarize the current knowledge linking ER stress and UPR to GC; we also discuss the possible nodes of therapeutic intervention and propose directions of future research.

Curcuminoid B63 induces ROS-mediated paraptosis-like cell death by targeting TrxR1 in gastric cells

Gastric cancer is one of the leading causes of cancer-related deaths. Chemotherapy has improved long-term survival of patients with gastric cancer. Unfortunately, cancer readily develops resistance to apoptosis-inducing agents. New mechanisms, inducing caspase-independent paraptosis-like cell death in cancer cells is presently emerging as a potential direction. We previously developed a curcumin analog B63 as an anti-cancer agent in pre-clinical evaluation. In the present study, we evaluated the effect and mechanism of B63 on gastric cancer cells. Our studies show that B63 targets TrxR1 protein and increases cellular reactive oxygen species (ROS) level, which results in halting gastric cancer cells and inducing caspase-independent paraptotic modes of death. The paraptosis induced by B63 was mediated by ROS-mediated ER stress and MAPK activation. Either overexpression of TrxR1 or suppression of ROS normalized B63-induced paraptosis in gastric cancer cells. Furthermore, B63 caused paraptosis in 5-fluorouracil-resistant gastric cancer cells, and B63 treatment reduced the growth of gastric cancer xenografts, which was associated with increased ROS and paraptosis. Collectively, our findings provide a novel strategy for the treatment of gastric cancer by utilizing TrxR1-mediated oxidative stress generation and subsequent cell paraptosis.

Inhibiting TrxR suppresses liver cancer by inducing apoptosis and eliciting potent antitumor immunity

Liver cancer is one of the most common malignant tumors worldwide. Thioredoxin reductase (TrxR) is highly expressed in liver cancer cells. The present study aimed to investigate the effect of inhibiting TrxR on liver cancer and to better understand the underlying molecular and immuno-logical mechanisms associated with inhibition. It was demonstrated that targeting TrxR inhibited the growth and induced apoptosis of liver cancer cells, which was accompanied by activation of the mitogen associated protein kinase pathway. This inhibition was dependent on the production of reactive oxygen species (ROS). Blockage of ROS production reversed TrxR inhibitor‑induced antitumor effects. Blocking the Trx/TrxR system activated the mammalian target of rapamycin pathway and inhibited autophagy, which occurred in a ROS‑independent manner. TrxR inhibition led to lesions in the mitochondrial membrane, indicated by alterations in membrane potential. Mouse xenograft experiments were highly consistent with in vitro studies. Most importantly, blocking the Trx/TrxR system improved the tumor immune microenvironment. Together, these data demonstrated that TrxR is a potential target for liver cancer therapy, which could inhibit hepatocarcinogenesis and progression, and improve the antitumor immune response.

MiR-155 aggravated septic liver injury by oxidative stress-mediated ER stress and mitochondrial dysfunction via targeting Nrf-2

OBJECTIVE

Liver is uniquely vulnerable during sepsis. MicroRNA-155 (miR-155) is confirmed to play crucial roles in septic liver injury. The present study aims to investigate the mechanisms of miR-155 in septic liver injury.

METHODS

The sepsis model was established by intraperitoneal injection of lipopolysaccharide (LPS) in mice. Mice were divided into four groups: Vehicle, miR-155 antagomir, LPS, LPS+ miR-155 antagomir. The survival rate and body weight were monitored. Liver injury was assessed by H&E staining. The levels of serum ALT and inflammatory cytokines were determined by ELISA kits. Oxidative stress was detected by MDA and SOD detection kits. The miR-155, Nrf-2, and markers related to oxidative stress, endoplasmic reticulum (ER) stress, mitochondrial injury and apoptosis were detected by western blotting and qPCR. Apoptosis in liver tissues was detected by TUNELstaining.

RESULTS

MiR-155 antagomir alleviated liver injury as evidenced by enhancing survival rate and body weight, inhibiting inflammatory cell infiltration, liver cells necrosis and decreasing ALT level. The productions of TNF-α, IL-6 were suppressed, while anti-inflammatory cytokine IL-10 was promoted by miR-155 antagomir. Oxidative stress was inhibited by miR-155 antagomir via enhancing nuclear factor, erythroid 2-like 2 (Nrf-2) expression. ER stress and Cytochrome C (Cyto-C) release were restrained by miR-155 antagomir. Sepsis-induced apoptosis was repressed by miR-155 antagomir as manifested by the decreased levels of Bax, cleaved caspase-12, 9 and 3, and increased levels of Bcl-2 and uncleaved PARP.

CONCLUSION

MiR-155 antagomir relieved septic liver injury through inhibiting oxidative stress-mediated ER stress, mitochondrial dysfunction and apoptosis via targeting Nrf-2, suggesting miR-155 as a therapeutic target for septic liver injury.

The Mutant p53-Targeting Compound APR-246 Induces ROS-Modulating Genes in Breast Cancer Cells

TP53 is the most frequently mutated gene in human cancer and thus an attractive target for novel cancer therapy. Several compounds that can reactive mutant p53 protein have been identified. APR-246 is currently being tested in a phase II clinical trial in high-grade serous ovarian cancer. We have used RNA-seq analysis to study the effects of APR-246 on gene expression in human breast cancer cell lines. Although the effect of APR-246 on gene expression was largely cell line dependent, six genes were upregulated across all three cell lines studied, i.e., TRIM16, SLC7A11, TXNRD1, SRXN1, LOC344887, and SLC7A11-AS1. We did not detect upregulation of canonical p53 target genes such as CDKN1A (p21), 14-3-3σ, BBC3 (PUMA), and PMAIP1 (NOXA) by RNA-seq, but these genes were induced according to analysis by qPCR. Gene ontology analysis showed that APR-246 induced changes in pathways such as response to oxidative stress, gene expression, cell proliferation, response to nitrosative stress, and the glutathione biosynthesis process. Our results are consistent with the dual action of APR-246, i.e., reactivation of mutant p53 and modulation of redox activity. SLC7A11, TRIM16, TXNRD1, and SRXN1 are potential new pharmacodynamic biomarkers for assessing the response to APR-246 in both preclinical and clinical studies.

A mono-carbonyl analog of curcumin induces apoptosis in drug-resistant EGFR-mutant lung cancer through the generation of oxidative stress and mitochondrial dysfunction

Introduction

Targeted therapies using epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) have revolutionized the treatment of non-small cell lung cancer (NSCLC) patients harboring EGFR mutations, leading to the approval of gefitinib and erlotinib as standard first-line clinical treatment. Inevitably, a considerable proportion of patients develop resistance to EGFR-TKIs due to the acquisition of secondary mutations within EGFR. Therefore, alternative strategies to target NSCLC are desperately needed.

Materials and methods

In this study, we have evaluated the effect of a reactive oxygen species (ROS)-inducing agent WZ35, a mono-carbonyl analog of curcumin, to target an inherent biological property of cancer cells, increased oxidative stress. To study whether WZ35 can inhibit NSCLC tumorigenesis, we used gefitinib- and erlotinib-resistant cell line H1975.

Results

In this study, we show that WZ35 treatment dramatically decreases cell viability and induces apoptosis in H1975 cells through the generation of ROS. We also found that the antitumor activity of WZ35 involved ROS-mediated activation of the endoplasmic reticulum stress pathway and mitochondrial dysfunction. Furthermore, WZ35 significantly inhibited H1975 xenograft tumor growth through the inhibition of cell proliferation and induction of apoptosis.

Discussion

These findings show that WZ35 may be a promising candidate for the treatment of EGFR-TKI-resistant NSCLC.

Oxidative stress-modulating drugs have preferential anticancer effects - involving the regulation of apoptosis, DNA damage, endoplasmic reticulum stress, autophagy, metabolism, and migration

To achieve preferential effects against cancer cells but less damage to normal cells is one of the main challenges of cancer research. In this review, we explore the roles and relationships of oxidative stress-mediated apoptosis, DNA damage, ER stress, autophagy, metabolism, and migration of ROS-modulating anticancer drugs. Understanding preferential anticancer effects in more detail will improve chemotherapeutic approaches that are based on ROS-modulating drugs in cancer treatments.

Mechanism of As2O3-Induced Action Potential Prolongation and Using hiPS-CMs to Evaluate the Rescue Efficacy of Drugs With Different Rescue Mechanism

Arsenic trioxide (As2O3) has been verified as a breakthrough in the management of acute promyelocytic leukemia in recent decades. However, cardiotoxicity, especially long QT syndrome (LQTS) has become the most important issue during As2O3 treatment. The characterized mechanisms behind this adverse effect are inhibition of cardiac hERG channel trafficking and increase of cardiac calcium currents. In our study, we found a new pathway underlying As2O3-induced cardiotoxicity that As2O3 accelerates lysosomal degradation of hERG on plasma membrane after using brefeldin A (BFA) to block protein trafficking. Then we explored pharmacological rescue strategies on As2O3-induced LQTS, and found that 4 therapeutic agents exert rescue efficacy via 3 different pathways: fexofenadine and astemizole facilitate hERG trafficking via promotion of channel-chaperone formation after As2O3 incubation; ranolazine slows hERG degradation in the presence of As2O3; and resveratrol shows significant attenuation on calcium current increase triggered by As2O3. Moreover, we used human-induced pluripotent stem cell derived cardiomyocytes (hiPS-CMs) to evaluate the rescue effects of the above agents on As2O3-induced prolongation of action potential duration (APD) and demonstrated that fexofenadine and resveratrol significantly ameliorate the prolonged APD. These observations suggested that pharmacological chaperone like fexofenadine and resveratrol might have the potential to protect against the cardiotoxicity of As2O3.

Proteomic Identification of the Galectin-1-Involved Molecular Pathways in Urinary Bladder Urothelial Carcinoma

Among various heterogeneous types of bladder tumors, urothelial carcinoma is the most prevalent lesion. Some of the urinary bladder urothelial carcinomas (UBUCs) develop local recurrence and may cause distal invasion. Galectin-1 de-regulation significantly affects cell transformation, cell proliferation, angiogenesis, and cell invasiveness. In continuation of our previous investigation on the role of galectin-1 in UBUC tumorigenesis, in this study, proteomics strategies were implemented in order to find more galectin-1-associated signaling pathways. The results of this study showed that galectin-1 knockdown could induce 15 down-regulated proteins and two up-regulated proteins in T24 cells. These de-regulated proteins might participate in lipid/amino acid/energy metabolism, cytoskeleton, cell proliferation, cell-cell interaction, cell apoptosis, metastasis, and protein degradation. The aforementioned dys-regulated proteins were confirmed by western immunoblotting. Proteomics results were further translated to prognostic markers by analyses of biopsy samples. Results of cohort studies demonstrated that over-expressions of glutamine synthetase, alcohol dehydrogenase (NADP⁺), fatty acid binding protein 4, and toll interacting protein in clinical specimens were all significantly associated with galectin-1 up-regulation. Univariate analyses showed that de-regulations of glutamine synthetase and fatty acid binding protein 4 in clinical samples were respectively linked to disease-specific survival and metastasis-free survival.

Curcumin enhances the effects of irinotecan on colorectal cancer cells through the generation of reactive oxygen species and activation of the endoplasmic reticulum stress pathway

Although initially effective against metastatic colorectal cancer (CRC), irinotecan-based chemotherapy leads to resistance and adverse toxicity. Curcumin is well known for its anti-cancer effects in many cancers, including CRC. Here, we describe reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress as important mechanisms by which curcumin enhances irinotecan's effects on CRC cells. CRC cell lines were treated with curcumin and/or irinotecan for 24 h, and then evaluated using cell proliferation assays, cell apoptosis assays, cell cycle analysis, intracellular Ca²⁺ measurements, ROS measurements and immunoblotting for key ER stress-related proteins. We found that cell viability was inhibited and apoptosis was increased, accompanied by ROS generation and ER stress activation in CRC cells treated with curcumin alone or in combination with irinotecan. Blocking ROS production attenuated the expression of two markers of ER stress: binding of immunoglobulin protein (BIP) and CCAAT/enhancer-binding protein homologous protein (CHOP). Blocking CHOP expression using RNA interference also inhibited ROS generation. These results demonstrated that curcumin could enhance the effects of irinotecan on CRC cells by inhibiting cell viability and inducing cell cycle arrest and apoptosis, and that these effects may be mediated, in part, by ROS generation and activation of the ER stress pathway.

Induction of the mitochondria-mediated apoptosis in human esophageal cancer cells by DS2, a newly synthetic diterpenoid analog, is regulated by Bax and caused by generation of reactive oxygen species

Ent-kaurane diterpene compounds have attracted considerable attention in recent years due to its antitumor, antibacterial, and antiviral activities. However, the clinical development of natural kaurane diterpenes, for example, oridonin for cancer therapy has been hampered by its relatively moderate potency, limited bioavailability. Herein, we report a newly synthetic analog of natural ent-kaurane diterpene, DS2, which exhibits significantly improved activity of antiproliferation against various cancer cell lines relative to oridonin. DS2 treatment triggers the mitochondria-mediated apoptosis and cell cycle arrest in human esophageal cancer cell lines (EC9706, EC109). Interestingly, normal human esophageal epithelial cells (HEECs) and normal human liver cells (HL-7702) are both significantly more resistant to the growth inhibition by DS2 compared with esophageal cancer cells. The DS2-induced apoptosis in EC9706 cells correlated with the drop of mitochondrial membrane potential (MMP), release of cytochrome c into the cytosol and activation of caspase-9 and -3. The induction of proapoptotic proteins p21 and Bax were also observed in DS2-treated cells. The DS2-induced apoptosis was significantly attenuated by knockdown of Bax proteins. Meanwhile, the DS2 treatment caused generation of reactive oxygen species (ROS) in human esophageal cancer cells, but not in HEECs, which was attenuated by pretreatment with ROS scavenger N-acetylcysteine (NAC). More interestingly, the antioxidants pretreatment completely attenuated DS2 mediated loss of the MMP and apoptosis, as well as Bax expression and growth inhibition. In conclusion, the present study reveals that the mitochondria-mediated cell death by DS2 is associated with Bax regulation and ROS generation, and understanding the function and mechanism of DS2 will help us to design better anti-cancer drugs.

Cancer-Targeting Functionalization of Selenium-Containing Ruthenium Conjugate with Tumor Microenvironment-Responsive Property to Enhance Theranostic Effects

A mutifunctional ruthenium-based conjugate Ru-BSe was designed and synthesized. The Ru complex with favorable bioimaging function was covalently linked with a cancer-targeted molecule that could be effectively internalized by the tumor to realize enhanced theranostic effects. The pH-response of the Ru conjugate in tumor acidic microenvironment causes ligand substitution and release of therapeutic complex. This activated complex remains inert to the reducing biomolecule-glutathione and terminally locates in mitochondria, in which it triggers oxidative stress, and activates intrinsic apoptosis. Real-time monitoring reveals that this Ru conjugate could selectively accumulate in tumor tissue in vivo, which significantly suppresses tumor progression and alleviate the damage to normal organs, realizing the precise cancer theranosis.

Santamarine Inhibits NF-κB Activation and Induces Mitochondrial Apoptosis in A549 Lung Adenocarcinoma Cells via Oxidative Stress

Santamarine (STM), a sesquiterpene lactone component of Magnolia grandiflora and Ambrosia confertiflora, has been shown to possess antimicrobial, antifungal, antibacterial, anti-inflammatory, and anticancer activities. However, no study has yet been conducted to investigate the molecular mechanism of STM-mediated anticancer activity. In the present study, we found that STM inhibits growth and induces apoptosis in A549 lung adenocarcinoma cells through induction of oxidative stress. STM induces oxidative stress by promoting reactive oxygen species (ROS) generation, depleting intracellular glutathione (GSH), and inhibiting thioredoxin reductase (TrxR) activity in a dose-dependent manner. Further mechanistic study demonstrated that STM induces apoptosis by modulation of Bax/Bcl-2 expressions, disruption of mitochondrial membrane potential, activation of caspase-3, and cleavage of PARP in a dose-dependent manner. Moreover, STM inhibited the constitutive and inducible translocation of NF-κBp65 into the nucleus. IKK-16 (I-κB kinase inhibitor) augmented the STM-induced apoptosis, indicating that STM induces apoptosis in A549 cells at least in part through NF-κB inhibition. Finally, STM-induced apoptosis and expressions of apoptosis regulators were effectively inhibited by thiol antioxidant N-acetyl-L-cysteine (NAC), indicating that STM exerts its anticancer effects mainly through oxidative stress. To the best of our knowledge, this is the first report providing evidence of anticancer activity and molecular mechanism of STM.

Novel allylated monocarbonyl analogs of curcumin induce mitotic arrest and apoptosis by reactive oxygen species-mediated endoplasmic reticulum stress and inhibition of STAT3

Curcumin is a promising active compound from a natural source and is extensively being tested in clinical trials because of its bio-functional properties. However, poor bioavailability has hampered its clinical application. Numerous attempts have been made in our laboratory to discover analogs of curcumin with enhanced bioavailability and superior pharmacological activity. In this study, we have investigated a new series of allylated monocarbonyl analogs of curcumin (MAC) and tested their effect on gastric cancer cells. Our results show six MAC that selectively targeted cancer cell lines to inhibit growth and induce apoptosis. This activity was achieved by generation of reactive oxygen species (ROS) by MAC. We selected one effective MAC (CA10) for further investigation and show that CA10 inhibits cell growth by causing G2/M cell cycle arrest and induction of apoptotic death. CA10 induced ROS generation and subsequent activation of endoplasmic reticulum (ER) stress and inhibition of signal transducer and activator of transcription 3 (STAT3) phosphorylation, inhibits cancer cell proliferation. These anti-tumor activities of CA10 were confirmed in gastric cancer xenografts. CA10 induced ROS, activated the ER stress pathway and inhibited STAT3 phosphorylation and gastric xenografts tumor growth in mice. Our studies provide experimental evidence that MAC CA10 effectively targets gastric cancer in preclinical models by enhancing ROS and ROS-mediated signaling.

Alantolactone induces apoptosis, promotes STAT3 glutathionylation and enhances chemosensitivity of A549 lung adenocarcinoma cells to doxorubicin via oxidative stress

Alantolactone (ALT), a sesquiterpene lactone component of Inula helenium, has been reported to exert anticancer activity in various cancers. However, the cellular targets and underlying mechanism of anticancer activity of ALT in various cancers including lung cancer has not been fully defined. In the present study, we found that ALT effectively inhibits proliferation and triggers oxidative stress mediated-apoptosis in A549 lung adenocarcinoma cells by inducing ER stress and mitochondrial dysfunction. This ALT-mediated apoptosis was inhibited by NAC while diamide potentiated it. Moreover, ALT effectively suppressed both constitutive and inducible STAT3 activation, inhibited its translocation into nucleus and decreased its DNA binding activity. Further mechanistic study revealed that ALT abrogated STAT3 activation by promoting STAT3 glutathionylation. ROS scavenger NAC reverted ALT-mediated STAT3 glutathionylation and inhibition of STAT3 phosphorylation. Finally, ALT enhanced chemosensitivity of A549 cells to doxorubicin and reversed doxorubicin resistance in A549/DR cells by inhibiting STAT3 activation and P-glycoprotein expression and increasing intracellular accumulation of doxorubicin. Suppression of STAT3 activation by targeting ROS metabolism with ALT thus discloses a previously unrecognized mechanism underlying the biological activity of ALT. Taken together; ALT induces oxidative stress-dependent apoptosis, inhibits STAT3 activation and augments doxorubicin toxicity in A549 lung cancer cells. These findings provide an in-depth insight into the molecular mechanism of ALT in the treatment of lung cancer.

M4IDP, a zoledronic acid derivative, induces G1 arrest, apoptosis and autophagy in HCT116 colon carcinoma cells via blocking PI3K/Akt/mTOR pathway

AIMS

The aim of this work was to examine the antitumor effects and mechanisms of M₄IDP, a zoledronic acid derivative, on human colorectal cancer (CRC) HCT116 cells.

MAIN METHODS

The effects of M₄IDP on proliferation, cell cycle and ROS production were determined by CCK-8 and flow cytometry assays. Annexin-V-FITC/PI, Hoechst 33258, MDC staining assays and Ad-mCherry-GFP-LC3B fluorescence assay were performed to investigate apoptosis and autophagy. The effects of M₄IDP on the induction of ER stress as well as the expression of cell cycle, apoptosis and autophagy-related proteins were analyzed by western blot assay.

KEY FINDINGS

M₄IDP exhibited strong and sustained inhibitory effect on the growth of HCT116 cells. G1 arrest caused by M₄IDP might be attributed to the enhancement of p27 and reduction of cyclin D1 expression. Proper-time treatment of M₄IDP activated autophagy and promoted autophagic flux, while long-time treatment might inhibit the autophagic degradation and undermine the autophagy. M₄IDP-induced apoptosis and autophagy were related to the ROS production and subsequent ER stress. M₄IDP treatment increased the expression of PTEN, inhibited the phosphorylation of PDK1, Akt, mTOR, p70S6K, and increased the phosphorylation of GSK-3β and Bad, suggesting that the inhibition of PI3K/Akt/mTOR pathway might be involved in the antitumor activities of M₄IDP.

SIGNIFICANCE

Our study indicates the antitumor properties of M₄IDP and its potential clinical use in CRC therapy by blocking PI3K/Akt/mTOR pathway. This study also provides a better understanding of the antitumor effects and the underlying mechanisms of bisphosphonates in the field of CRC therapy.

Thapsigargin sensitizes human esophageal cancer to TRAIL-induced apoptosis via AMPK activation

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent for esophageal squamous cell carcinoma (ESCC). Forced expression of CHOP, one of the key downstream transcription factors during endoplasmic reticulum (ER) stress, upregulates the death receptor 5 (DR5) levels and promotes oxidative stress and cell death. In this study, we show that ER stress mediated by thapsigargin promoted CHOP and DR5 synthesis thus sensitizing TRAIL treatment, which induced ESCC cells apoptosis. These effects were reversed by DR5 siRNA in vitro and CHOP siRNA both in vitro and in vivo. Besides, chemically inhibition of AMPK by Compound C and AMPK siRNA weakened the anti-cancer effect of thapsigargin and TRAIL co-treatment. Therefore, our findings suggest ER stress effectively sensitizes human ESCC to TRAIL-mediated apoptosis via the TRAIL-DR5-AMPK signaling pathway, and that activation of ER stress may be beneficial for improving the efficacy of TRAIL-based anti-cancer therapy.

Synergistic antitumor activity of rapamycin and EF24 via increasing ROS for the treatment of gastric cancer

Mechanistic/mammalian target of rapamycin (mTOR) has emerged as a new potential therapeutic target for gastric cancer. Rapamycin and rapamycin analogs are undergoing clinical trials and have produced clinical responses in a subgroup of cancer patients. However, monotherapy with rapamycin at safe dosage fails to induce cell apoptosis and tumor regression which has hampered its clinical application. This has led to the exploration of more effective combinatorial regimens to enhance the effectiveness of rapamycin. In our present study, we have investigated the combination of rapamycin and a reactive oxygen species (ROS) inducer EF24 in gastric cancer. We show that rapamycin increases intracellular ROS levels and displays selective synergistic antitumor activity with EF24 in gastric cancer cells. This activity was mediated through the activation of c-Jun N terminal kinase and endoplasmic reticulum stress (ER) pathways in cancer cells. We also show that inhibiting ROS accumulation reverses ER stress and prevents apoptosis induced by the combination of rapamycin and EF24. These mechanisms were confirmed using human gastric cancer xenografts in immunodeficient mice. Taken together, our work provides a novel therapeutic strategy for the treatment of gastric cancer. The work reveals that ROS generation could be an important target for the development of new combination therapies for cancer treatment.