Curcuminoid WZ26, a TrxR1 inhibitor, effectively inhibits colon cancer cell growth and enhances cisplatin-induced cell death through the induction of ROS

Exploring the Thioredoxin System as a Therapeutic Target in Cancer: Mechanisms and Implications

Cells constantly face the challenge of managing oxidants. In aerobic organisms, oxygen (O2) is used for energy production, generating reactive oxygen species (ROS) as byproducts of enzymatic reactions. To protect against oxidative damage, cells possess an intricate system of redox scavengers and antioxidant enzymes, collectively forming the antioxidant defense system. This system maintains the redox equilibrium and enables the generation of localized oxidative signals that regulate essential cellular functions. One key component of this defense is the thioredoxin (Trx) system, which includes Trx, thioredoxin reductase (TrxR), and NADPH. The Trx system reverses oxidation of macromolecules and indirectly neutralizes ROS via peroxiredoxin (Prx). This dual function protects cells from damage accumulation and supports physiological cell signaling. However, the Trx system also shields tumors from oxidative damage, aiding their survival. Due to elevated ROS levels from their metabolism, tumors often rely on the Trx system. In addition, the Trx system regulates critical pathways such as proliferation and neoangiogenesis, which tumors exploit to enhance growth and optimize nutrient and oxygen supply. Consequently, the Trx system is a potential target for cancer therapy. The challenge lies in selectively targeting malignant cells without disrupting the redox equilibrium in healthy cells. The aim of this review article is threefold: first, to elucidate the function of the Trx system; second, to discuss the Trx system as a potential target for cancer therapies; and third, to present the possibilities for inhibiting key components of the Trx system, along with an overview of the latest clinical studies on these inhibitors.

Rosmarinic Acid Potentiates Cytotoxicity of Cisplatin against Colorectal Cancer Cells by Enhancing Apoptotic and Ferroptosis

Rosmarinic acid (RA) has demonstrated anticancer effects on several types of malignancies. However, whether RA promotes the anticancer effect of cisplatin on colorectal cancer cells remains sketchy. This study aimed to explore whether RA potentiates the cytotoxicity of cisplatin against colon cancer cells and the underlying mechanism. Cell viability, cell cycle progression, and apoptosis was evaluated using sulforhodamine B (SRB) assay, flow cytometric analysis, and propidium iodide/Annexin V staining, respectively. Western blotting was utilized to analyze signaling pathways. Our findings showed that RA significantly enhanced the inhibitory effect on cell viability and the induction of apoptosis on the colon cancer cell lines DLD-1 and LoVo. Signaling cascade analysis revealed that the combination of RA and cisplatin jointly induced Bax and caspase activation while downregulating Bcl-2, glutathione peroxidase 4 (GPX4), and SLC7A11 in DLD-1 cells. Moreover, caspase inhibitor and ferroptosis inhibitor significantly reversed the inhibition of cell viability in response to RA combined with cisplatin. Collectively, these findings demonstrate that RA enhances the cytotoxicity of cisplatin against colon cancer cells, attributing to the promotion of apoptosis and ferroptosis.

Oxidative cell death in cancer: mechanisms and therapeutic opportunities

Reactive oxygen species (ROS) are highly reactive oxygen-containing molecules generated as natural byproducts during cellular processes, including metabolism. Under normal conditions, ROS play crucial roles in diverse cellular functions, including cell signaling and immune responses. However, a disturbance in the balance between ROS production and cellular antioxidant defenses can lead to an excessive ROS buildup, causing oxidative stress. This stress damages essential cellular components, including lipids, proteins, and DNA, potentially culminating in oxidative cell death. This form of cell death can take various forms, such as ferroptosis, apoptosis, necroptosis, pyroptosis, paraptosis, parthanatos, and oxeiptosis, each displaying distinct genetic, biochemical, and signaling characteristics. The investigation of oxidative cell death holds promise for the development of pharmacological agents that are used to prevent tumorigenesis or treat established cancer. Specifically, targeting key antioxidant proteins, such as SLC7A11, GCLC, GPX4, TXN, and TXNRD, represents an emerging approach for inducing oxidative cell death in cancer cells. This review provides a comprehensive summary of recent progress, opportunities, and challenges in targeting oxidative cell death for cancer therapy.

Thioredoxin system in colorectal cancer: Its role in carcinogenesis, disease progression, and response to treatment

The thioredoxin system is essential for many physiological processes, including the maintenance of redox signalling pathways. Alterations in the activity, expression and interactions with other signalling pathways can lead to protective or pathophysiological responses. Thioredoxin and thioredoxin reductase, the two main components of this system, are often overexpressed in cancer, including colorectal cancer. This overexpression is often linked with tumour progression and poor outcomes. This review discusses the role of the Trx system in driving colorectal carcinogenesis and disease progression, as well as the challenges of targeting this system. Additionally, the recent advancements in the development of novel and effective thioredoxin inhibitors for colorectal cancer are also explored.

Jolkinolide B synergistically potentiates the antitumor activity of GPX4 inhibitors via inhibiting TrxR1 in cisplatin-resistant bladder cancer cells

Glutathione peroxidase 4 (GPX4) is a promising anticancer therapeutic target; however, the application of GPX4 inhibitors (GPX4i) is limited owing to intrinsic or acquired drug resistance. Hence, understanding the mechanisms underlying drug resistance and discovering molecules that can overcome drug resistance are crucial. Herein, we demonstrated that GPX4i killed bladder cancer cells by inducing lipid reactive oxygen species-mediated ferroptosis and apoptosis, and cisplatin-resistant bladder cancer cells were also resistant to GPX4i, representing a higher half-maximal inhibitory concentration value than that of parent bladder cancer cells. In addition, thioredoxin reductase 1 (TrxR1) overexpression was responsible for GPX4i resistance in cisplatin-resistant bladder cancer cells, and inhibiting TrxR1 restored the sensitivity of these cells to GPX4i. In vitro and in vivo studies revealed that Jolkinolide B (JB), a natural diterpenoid and previously identified as a TrxR1 inhibitor, potentiated the antiproliferative efficacy of GPX4i (RSL3 and ML162) against cisplatin-resistant bladder cancer cells. Furthermore, GPX4 knockdown and inhibition could augment JB-induced paraptosis and apoptosis. Our results suggest that inhibiting TrxR1 can effectively improve GPX4 inhibition-based anticancer therapy. A combination of JB and GPX4i, which is well-tolerated and has several anticancer mechanisms, may serve as a promising therapy for treating bladder cancer.

Thioredoxin (Trx): A redox target and modulator of cellular senescence and aging-related diseases

Thioredoxin (Trx) is a compact redox-regulatory protein that modulates cellular redox state by reducing oxidized proteins. Trx exhibits dual functionality as an antioxidant and a cofactor for diverse enzymes and transcription factors, thereby exerting influence over their activity and function. Trx has emerged as a pivotal biomarker for various diseases, particularly those associated with oxidative stress, inflammation, and aging. Recent clinical investigations have underscored the significance of Trx in disease diagnosis, treatment, and mechanistic elucidation. Despite its paramount importance, the intricate interplay between Trx and cellular senescence-a condition characterized by irreversible growth arrest induced by multiple aging stimuli-remains inadequately understood. In this review, our objective is to present a comprehensive and up-to-date overview of the structure and function of Trx, its involvement in redox signaling pathways and cellular senescence, its association with aging and age-related diseases, as well as its potential as a therapeutic target. Our review aims to elucidate the novel and extensive role of Trx in senescence while highlighting its implications for aging and age-related diseases.

PEG-modified nano liposomes co-deliver Apigenin and RAGE-siRNA to protect myocardial ischemia injury

Ischemic heart disease (IHD) is a cardiac disorder in which myocardial damage occurs as a result of myocardial ischemia and hypoxia. Evidence suggests that oxidative stress and inflammatory responses are critical in the development of myocardial ischemia. Therefore, the combination of antioxidant and anti-inflammatory applications is an effective strategy to combat ischemic heart disease. In this paper, polyethylene glycol (PEG)-modified cationic liposomes were used as carriers to deliver apigenin (Apn) with small interfering RNA (siRNA) targeting the receptor for glycosylation end products (RAGE) (siRAGE) into cardiomyocytes to prevent myocardial ischemic injury through antioxidant and anti-inflammatory effects. Our results showed that we successfully prepared cationic PEG liposomes loaded with Apn and siRAGE (P-CLP-A/R) with normal appearance and morphology, particle size and Zeta potential, and good encapsulation rate, drug loading and in vitro release degree. In vitro, P-CLP-A/R was able to prevent oxidative stress injury in H9C2 cells, downregulate the expression of RAGE, reduce the secretion of cellular inflammatory factors and inhibit apoptosis through the RAGE/NF-κB pathway; In vivo, P-CLP-A/R was able to prevent arrhythmia and myocardial pathological injury, and reduce apoptosis and the area of necrotic myocardium in rats. In conclusion, P-CLP-A/R has a protective effect on myocardial ischemic injury and is expected to be a potential drug for the prevention of ischemic heart disease in the future.

Anti-photoaging effect and mechanism of flexible liposomes co-loaded with apigenin and doxycycline

Prolonged exposure to UV light can lead to photo-ageing of the skin. Therefore, the development and application of anti-photoaging drugs is urgent. In this study, we co-loaded apigenin (Apn) and doxycycline (Doc), a broad-spectrum inhibitor of matrix metalloproteinases (MMPs), into flexible liposomes to exert anti-photoaging effects by combating oxidative stress, anti-inflammation, reducing the activation of MMPs and preventing collagen loss. The results showed that we prepared a flexible liposome (A/D-FLip) containing Apn and Doc. Its appearance, particle size and Zeta potential were normal and it had good encapsulation efficiency, drug loading, in vitro release and transdermal efficiency. In cellular experiments, A/D-FLip could inhibit oxidative stress damage, reduce inflammatory factors and decrease the activation of MMPs in Human immortalized keratinocytes (HaCaT) cells; in animal experiments, A/D-FLip could inhibit skin damage and reduce skin collagen loss by decreasing the activation of MMPs, thus inhibiting skin photoaging in mice. In conclusion, A/D-FLip has good anti-photoaging effects and it has the potential to become an effective skin care product or drug against UV damage and skin photoaging in the future.

LCS-1 inhibition of superoxide dismutase 1 induces ROS-dependent death of glioma cells and degradates PARP and BRCA1

Gliomas are characterized by high morbidity and mortality, and have only slightly increased survival with recent considerable improvements for treatment. An innovative therapeutic strategy had been developed via inducing ROS-dependent cell death by targeting antioxidant proteins. In this study, we found that glioma tissues expressed high levels of superoxide dismutase 1 (SOD1). The expression of SOD1 was upregulated in glioma grade III and V tissues compared with that in normal brain tissues or glioma grade I tissues. U251 and U87 glioma cells expressed high levels of SOD1, low levels of SOD2 and very low levels of SOD3. LCS-1, an inhibitor of SOD1, increased the expression SOD1 at both mRNA and protein levels slightly but significantly. As expected, LCS-1 caused ROS production in a dose- and time-dependent manner. SOD1 inhibition also induced the gene expression of HO-1, GCLC, GCLM and NQO1 which are targeting genes of nuclear factor erythroid 2-related factor 2, suggesting the activation of ROS signal pathway. Importantly, LCS-1 induced death of U251 and U87 cells dose- and time-dependently. The cell death was reversed by the pretreatment of cells with ROS scavenges NAC or GSH. Furthermore, LCS-1 decreased the growth of xenograft tumors formed by U87 glioma cells in nude mice. Mechanistically, the inhibition of P53, caspases did not reverse LCS-1-induced cell death, indicating the failure of these molecules involving in cell death. Moreover, we found that LCS-1 treatment induced the degradation of both PARP and BRCA1 simultaneously, suggesting that LCS-1-induced cell death may be associated with the failure of DNA damage repair. Taking together, these results suggest that the degradation of both PARP and BRCA1 may contribute to cell death induced by SOD1 inhibition, and SOD1 may be a target for glioma therapy.

Curcuminoids as Modulators of EMT in Invasive Cancers: A Review of Molecular Targets With the Contribution of Malignant Mesothelioma Studies

Curcuminoids, which include natural acyclic diarylheptanoids and the synthetic analogs of curcumin, have considerable potential for fighting against all the characteristics of invasive cancers. The epithelial-to-mesenchymal transition (EMT) is a fundamental process for embryonic morphogenesis, however, the last decade has confirmed it orchestrates many features of cancer invasiveness, such as tumor cell stemness, metabolic rewiring, and drug resistance. A wealth of studies has revealed EMT in cancer is in fact driven by an increasing number of parameters, and thus understanding its complexity has now become a cornerstone for defining future therapeutic strategies dealing with cancer progression and metastasis. A specificity of curcuminoids is their ability to target multiple molecular targets, modulate several signaling pathways, modify tumor microenvironments and enhance the host’s immune response. Although the effects of curcumin on these various parameters have been the subject of many reviews, the role of curcuminoids against EMT in the context of cancer have never been reviewed so far. This review first provides an updated overview of all EMT drivers, including signaling pathways, transcription factors, non-coding RNAs (ncRNAs) and tumor microenvironment components, with a special focus on the most recent findings. Secondly, for each of these drivers the effects of curcumin/curcuminoids on specific molecular targets are analyzed. Finally, we address some common findings observed between data reported in the literature and the results of investigations we conducted on experimental malignant mesothelioma, a model of invasive cancer representing a useful tool for studies on EMT and cancer.

Effect and Prognosis Factors of Combining Laparoscopic Radical Resection of Colon Adenocarcinoma with Docetaxel Therapy in Treating Middle and Advanced Colon Adenocarcinoma

Objective. The aim of the study is to explore the clinical efficacy and prognosis factors of joint application of laparoscopic radical resection of colon adenocarcinoma (COAD) and docetaxel therapy in treating COAD of middle and advanced stages. Methods. The clinical data of 103 COAD patients of middle and advanced stages treated in our hospital from July 2016 to July 2018 were selected for the retrospective analysis, all patients received the treatment scheme of combining laparoscopic radical resection of COAD with docetaxel therapy for the observation of short-term efficacy, follow-up was conducted to record their 3-year survival, and relevant factors affecting patient prognosis were analyzed by the logistic regression model. Results. After treatment, the total remission rate of patients was 75.73% (78/103), the total incidence rate of adverse reactions was 16.50% (17/103); patients’ level values of various serum tumor markers after treatment were significantly lower than those before treatment ( $P<0.001$ ); according to the univariate analysis results, for COAD patients with different tumor diameters, differentiated degrees, TNM stages, perineural invasion degrees, pathological types, and depths of invasion, their modality rates were statistically different ( $P<0.05$ ); and the logistic regression analysis showed that tumor diameter ≥5 cm, poor differentiation, TNM stage IV, perineural invasion, pathologically signet-ring cell carcinoma, and T3-invasion were the independent risk factors affecting patient prognosis ( $P<0.05$ ). Conclusion. Combining laparoscopic radical resection of COAD with docetaxel therapy in treating COAD of middle and advanced stages achieves affirmed short-term efficacy, which can reduce patients’ level of serum tumor markers and ensure high safety and good survival prognosis. Tumor diameter, differentiated degree, TNM stage, perineural invasion, pathological type, and T3-invasion are the relevant factors affecting the prognosis of middle and advanced COAD.

Bioactive food components for colorectal cancer prevention and treatment: A good match

Colorectal cancer (CRC) is the third most frequent cancer worldwide, accounts for about 10% of the total cancer cases, and ranks as the second cause of death by cancer. CRC is more prevalent in developed countries in close causal relation with occidental diets. Due to anatomy, the diet has a strong impact on CRC. High contents in meat are acknowledged risk factors whereas a diet rich in fruits and vegetables is an established CRC protective factor. Fruits and vegetables contain numerous Bioactive Food Components (BFCs), physiologically active food compounds, beneficial on health. Preventive and therapeutic benefits of BFCs in cancer have increasingly been reported over the past 20 years. BFCs show both chemopreventive and anti-tumor properties in CRC but more interestingly, abundant research describes BFCs as enhancers of conventional cancer treatments. Despite these promising results, their clinical transferability is slowed down by bioavailability interrogations and their poorly understood hormetic effect. In this review, we would like to reposition BFCs as well-fitted for applications in CRC. We provide a synthetic overview of trustworthy BFC applications in CRC, with a special highlight on combinatory approaches and conventional cancer treatment potentiation strategies.

MiR-15a-3p regulates ferroptosis via targeting glutathione peroxidase GPX4 in colorectal cancer

Colorectal cancer (CRC) is the second most common cancer-related deaths throughout the world. Ferroptosis is a recently regulated form of cell death, lately gains attention. MicroRNA-15a-3p (miR-15a-3p) plays a regulatory role in various kinds of cancers. However, the role of miR-15a-3p in cellular ferroptosis is still unclear. Here, we aimed to clarify whether miR-15a-3p could regulate the ferroptosis of CRC. Here we identified miR-15a-3p positively regulates ferroptosis via directly targeting glutathione peroxidase glutathione peroxidase 4 (GPX4) in CRC. Overexpression of miR-15a-3p repressed GPX4 through binding to the 3'-untranslated region of GPX4, resulting in increased reactive oxygen species level, intracellular Fe²⁺ level, and malondialdehyde accumulation in vitro and in vivo. Correspondingly, suppression of miR-15a-3p reduced the sensitivity of CRC cells to erastin and GPX4. Taken together, these data demonstrate that miR-15a-3p regulates ferroptosis through targeting GPX4 in CRC cells, illustrating the novel role of microRNA in ferroptosis.

Acetylated Thioredoxin Reductase 1 Resists Oxidative Inactivation

Thioredoxin Reductase 1 (TrxR1) is an enzyme that protects human cells against reactive oxygen species generated during oxidative stress or in response to chemotherapies. Acetylation of TrxR1 is associated with oxidative stress, but the function of TrxR1 acetylation in oxidizing conditions is unknown. Using genetic code expansion, we produced recombinant and site-specifically acetylated variants of TrxR1 that also contain the non-canonical amino acid, selenocysteine, which is essential for TrxR1 activity. We previously showed site-specific acetylation at three different lysine residues increases TrxR1 activity by reducing the levels of linked dimers and low activity TrxR1 tetramers. Here we use enzymological studies to show that acetylated TrxR1 is resistant to both oxidative inactivation and peroxide-induced multimer formation. To compare the effect of programmed acetylation at specific lysine residues to non-specific acetylation, we produced acetylated TrxR1 using aspirin as a model non-enzymatic acetyl donor. Mass spectrometry confirmed aspirin-induced acetylation at multiple lysine residues in TrxR1. In contrast to unmodified TrxR1, the non-specifically acetylated enzyme showed no loss of activity under increasing and strongly oxidating conditions. Our data suggest that both site-specific and general acetylation of TrxR1 regulate the enzyme’s ability to resist oxidative damage.

Protective Effects and Mechanisms of Recombinant Human Glutathione Peroxidase 4 on Isoproterenol-Induced Myocardial Ischemia Injury

Ischemic heart disease (IHD) is a cardiovascular disease with high fatality rate, and its pathogenesis is closely related to oxidative stress. Reactive oxygen species (ROS) in oxidative stress can lead to myocardial ischemia (MI) injury in many ways. Therefore, the application of antioxidants may be an effective way to prevent IHD. In recent years, glutathione peroxidase 4 (GPx4) has received increasing attention due to its antioxidant effect. In a previous study, we used the new chimeric tRNA^UTuT6 to express highly active recombinant human GPx4 (rhGPx4) in amber-less Escherichia coli. In this study, we established an isoproterenol- (ISO-) induced MI injury model in rats and an in vitro model to research the protective effect and mechanism of rhGPx4 on MI injury. The results showed that rhGPx4 could reduce the area of myocardial infarction and ameliorate the pathological injury of heart tissue, significantly reduce ISO-induced abnormalities on electrocardiogram (ECG) and cardiac serum biomarkers, protect mitochondrial function, and attenuate cardiac oxidative stress injury. In an in vitro model, the results also confirmed that rhGPx4 could inhibit ISO-induced oxidative stress injury and cardiomyocyte apoptosis. The mechanism of action of rhGPx4 involves not only the inhibition of lipid peroxidation by eliminating ROS but also keeping a normal level of endogenous antioxidant enzymes by eliminating ROS, thereby preventing oxidative stress injury in cardiomyocytes. Additionally, rhGPx4 could inhibit cardiomyocyte apoptosis through a mitochondria-dependent pathway. In short, rhGPx4, a recombinant antioxidant enzyme, can play an important role in the prevention of IHD and may have great potential for application.

MicroRNAs Involved in Oxidative Stress Processes Regulating Physiological and Pathological Responses

Oxidative stress influences several physiological and pathological cellular events, including cell differentiation, excessive growth, proliferation, apoptosis, and the inflammatory response. Therefore, oxidative stress is involved in the pathogenesis of various diseases, including pulmonary fibrosis, epilepsy, hypertension, atherosclerosis, Parkinson's disease, cardiovascular disease, and Alzheimer's disease. Recent studies have shown that several microRNAs (miRNAs) are involved in developing various diseases caused by oxidative stress and that miRNAs may be helpful to determine the inflammatory characteristics of immune responses during infection and disease. This review describes the known effects of miRNAs on reactive oxygen species to induce oxidative stress and the miRNA regulatory mechanisms involved in the uncoupling of Keap1-Nrf2 complexes. Finally, we summarized the functions of miRNAs in several antioxidant genes. Understanding the crosstalk between miRNAs and oxidative stress-inducing factors during physiological and pathological cellular events may have implications for designing more effective treatments for immune diseases.

A Novel Biological Activity of the STAT3 Inhibitor Stattic in Inhibiting Glutathione Reductase and Suppressing the Tumorigenicity of Human Cervical Cancer Cells via a ROS-Dependent Pathway

Introduction

Glutathione reductase (GSR) provides reduced glutathione (GSH) to maintain redox homeostasis. Inhibition of GSR disrupts this balance, resulting in cell damage, which benefits cancer therapy. However, the effect of GSR inhibition on the tumorigenicity of human cervical cancer is not fully understood.

Materials and Methods

Tissue microarray analysis was employed to determine GSR expression in cervical cancer tissues by immunohistochemical staining. Cell death was measured with PI/FITC-annexin V staining. mRNA levels were measured via quantitative RT-PCR. Protein expression was measured by Western blotting and flow cytometry. STAT3 deletion was performed with CRISPR/Cas9 technology. GSR knockdown was achieved by RNA interference. Reactive oxygen species (ROS) levels were measured by DCF staining. GSR enzymatic activity was measured with a GSR assay kit. The effect of GSR inhibition on the growth of tumors formed by cervical cancer cells was investigated using a xenograft model.

Results

The expression of GSR was increased in human cervical cancer tissues, as shown by immunohistochemical staining. GSR knockdown by RNA interference in human cervical cancer cell lines resulted in cell death, suggesting the ability of GSR to maintain cancer cell survival. The STAT3 inhibitor 6-nitrobenzo[b]thiophene 1,1-dioxide (Stattic) also inhibited the enzymatic activity of GSR and induced the death of cervical cancer cells. More importantly, Stattic decreased the growth of xenograft tumors formed by cervical cancer cells in nude mice. Mechanistically, tumor cell death induced by Stattic-mediated GSR inhibition was ROS-dependent, since the ROS scavengers GSH and N-acetyl cysteine (NAC) reversed the effect of Stattic. In contrast, pharmacological and molecular inhibition of STAT3 did not induce the death of cervical cancer cells, suggesting a STAT3-independent activity of Stattic.

Conclusion

Stattic inhibits the enzymatic activity of GSR and induces STAT3-independent but ROS-dependent death of cervical cancer cells, suggesting its potential application as a therapeutic agent for human cervical cancers.

Jolkinolide B targets thioredoxin and glutathione systems to induce ROS-mediated paraptosis and apoptosis in bladder cancer cells

Bladder cancer is a clinically heterogeneous disease with a poor prognosis. In the current study, anti-proliferation assay of a Euphorbiaceae diterpenoid library led to the identification of an anti-bladder cancer agent Jolkinolide B (JB). JB showed significant cytotoxicity against a panel of bladder cancer cell lines and suppressed the growth of cisplatin (CDDP)-resistant bladder cancer xenografts in single or combination treatments. Mechanistic study revealed that, besides inducing mitogen-activated protein kinase (MAPK)-related apoptosis, JB could trigger the paraptosis via activation of reactive oxygen species (ROS)-mediated endoplasmic reticulum (ER) stress and extracellular signal-regulated kinase (ERK) pathway. The excessive production of ROS could be induced by JB via inhibition of thioredoxin reductase 1 (TrxR1) and depletion of glutathione (GSH). Collectively, JB that targets thioredoxin and GSH systems to induce two distinct cell death modes may serve as a promising candidate in future anti-bladder cancer drug development.

Isoalantolactone Increases the Sensitivity of Prostate Cancer Cells to Cisplatin Treatment by Inducing Oxidative Stress

Prostate cancer is the most common malignancy among men worldwide. Platinum (II)-based chemotherapy has been used to treat a number of malignancies including prostate cancer. However, the potential of cisplatin for treating prostate cancer is restricted owing to its limited efficacy and toxic side effects. Combination therapies have been proposed to increase the efficacy and reduce the toxic side effects. In the present study, we investigated how isoalantolactone (IATL), a sesquiterpene lactone extracted from the medicinal plant Inula helenium L., acts synergistically with cisplatin on human prostate cancer cells. We show that IATL significantly increased cisplatin-induced growth suppression and apoptosis in human prostate cancer cells. Mechanistically, the combined treatment resulted in an excessive accumulation of intracellular reactive oxygen species (ROS), which leads to the activation of endoplasmic reticulum (ER) stress and the JNK signaling pathway in human prostate cancer cells. Pretreatment of cells with the ROS scavenger N-acetylcysteine (NAC) significantly abrogated the combined treatment-induced ROS accumulation and cell apoptosis. In addition, the activation of ER stress and the JNK signaling pathway prompted by IATL and cisplatin was also reversed by NAC pretreatment. In vivo, we found that IATL combined with cisplatin showed the strongest antitumor effects compared with single agents. These results support the notion that IATL and cisplatin combinational treatment may be more effective for treating prostate cancer than cisplatin alone.

Curcumin and cancer biology: Focusing regulatory effects in different signalling pathways

Cancer is the second-leading cause of death worldwide. Till date, many such effective treatments are available, for example chemotherapy, surgery, and radiation therapy, but there are severe associated side effects, such as increased infection risk, constipation, hair loss, anaemia, among others. Thus, the need for effective therapeutic strategies and screening methodology arises. Researchers around the world are increasingly trying to discover anticancer therapies with as few side effects as possible and many are now focusing on phytochemicals, like curcumin. Curcumin is a bright yellow substance isolated from the plant rhizomes of Curcuma longa L. To this molecule a high therapeutic benefit has been underlined, being able to alter the development of cancer by different mechanisms, such as regulating multiple microRNA expression, modifying a series of signalling pathways, that is, Akt, Bcl-2, PTEN, p53, Notch, and Erbb. Another major pathway that curcumin targets is the matrix metalloproteinase (MMP) gene expression. In fact, MMPs are responsible for the degradation of the cell-extracellular matrix, which can lead to the diseased condition and many different pathways contribute to its activity, such as JAK/STAT, NF-κB, MAPK/ERK, COX-2, ROS, TGF-β, among others. In this review, we have attempted to describe the curcumin regulatory effect on different cell signalling pathways involved in the progression of different types of cancers.

Compensatory combination of mTOR and TrxR inhibitors to cause oxidative stress and regression of tumors

Background: Cancer is a leading cause of death worldwide. Extensive research over decades has led to the development of therapies that inhibit oncogenic signaling pathways. The mammalian target of rapamycin (mTOR) signaling pathway plays an important role in the development of many cancers. Several mTOR inhibitors are approved for the treatment of cancers. However, the anticancer efficacies of mTOR inhibitor monotherapy are still limited.

Methods: Western blot was used to detect the expression of indicated molecules. Thioredoxin reductase (TrxR) activity in cells was determined by the endpoint insulin reduction assay. Immunofluorescence staining was used to analyze precise location and expression of target proteins. Nude mice were used for xenograft tumor models.

Results: We identified a synergistic lethal interaction of mTOR and TrxR inhibitors and elucidated the underlying molecular mechanisms of this synergism. We demonstrated that mTOR and TrxR inhibitors cooperated to induce cell death by triggering oxidative stress, which led to activation of autophagy, endoplasmic reticulum (ER) stress and c-Jun N-terminal Kinase (JNK) signaling pathway in cancer cells. Remarkably, we found that auranofin (AF) combined with everolimus significantly suppressed tumor growth in HCT116 and SGC-7901 xenograft models with no significant signs of toxicity.

Conclusion: Our findings identify a promising therapeutic combination for cancer and has important implications for developing mTOR inhibitor-based combination treatments.

Berberine accelerated wound healing by restoring TrxR1/JNK in diabetes

The high disability, mortality and morbidity of diabetic ulcers make it urgent to explore effective strategies for diabetic wound repair. TrxR1 plays a vital role in regulating redox homeostasis in various pathologies. In the present study, the effect of berberine (BBR) on diabetic wounds was investigated in streptozotocin (STZ)-induced diabetic rats and a high glucose (HG)-induced cell model, and the mechanism of BBR on TrxR1 was elucidated. BBR treatment remarkably accelerated wound healing and enhanced extracellular matrix (ECM) synthesis and significantly inhibited HG-induced HaCaT cell damage. Further analysis indicated that BBR activated TrxR1, suppressed its downstream JNK signaling, thereby inhibiting oxidative stress and apoptosis, promoted cell proliferation, down-regulated matrix metalloproteinase (MMP) 9 (MMP9) and up-regulated transforming growth factor-β1 (TGF-β1) and tissue inhibitors of MMP 1 (TIMP1), resulting in accelerated wound healing. Importantly, the enhancement of BBR on wound repair was further abolished by TrxR1 inhibitor. Moreover, in diabetic wounds induced by a combination of STZ injection and high-fat diet, BBR significantly increased wound closure rate and TrxR1 expression, and this was reversed by TrxR1 inhibitor. These data indicated that topical BBR treatment accelerated diabetic wound healing by activating TrxR1. Targeting TrxR1 may be a novel, effective strategy for restoring redox homeostasis and promoting diabetic wound healing.

Study on antioxidant effect of recombinant glutathione peroxidase 1

Glutathione peroxidase 1 (GPx1) is an important antioxidant selenium enzyme and has a good prospect for drug development. However, the expression of GPx1 requires a complex expression mechanism, which makes the drug development of recombinant GPx1 (rGPx1) difficult. In the previous study, we expressed highly active rhGPx1 in amber-less Escherichia coli by using a novel chimeric tRNA^UTuT6. However, the antioxidant effect of rhGPx1 at the cellular and animal levels has not been verified. In this study, we established isoproterenol (ISO)-induced oxidative stress injury models to study the antioxidant effect of rhGPx1 at the cellular and animal levels. Meanwhile, in order to more accurately reflect the antioxidant effect of rGPx1 in mice, we used the same method to express recombinant mouse GPx1 (rmGPx1) as a control for rhGPx1. The results of a study showed that rhGPx1 has a good antioxidant effect at the cellular and animal levels. However, due to species differences, rhGPx1 had immunogenicity in mice and antibodies of rhGPx1 could inhibit its antioxidant activity, so the antioxidant effect of rhGPx1 was not as good as rmGPx1 in mice. Nevertheless, this study provides a reliable theoretical basis for the development of rhGPx1 as an antioxidant drug.

The latest automated docking technologies for novel drug discovery

INTRODUCTION

Molecular docking has been consolidated as one of the most important methods in the molecular modeling field. It has been recognized as a prominent tool in the study of protein-ligand complexes, to describe intermolecular interactions, to accurately predict poses of multiple ligands, to discover novel promising bioactive compounds. Molecular docking methods have evolved in terms of their accuracy and reliability; but there are pending issues to solve for improving the connection between the docking results and the experimental evidence.

AREAS COVERED

In this article, the author reviews very recent innovative molecular docking applications with special emphasis on reverse docking, treatment of protein flexibility, the use of experimental data to guide the selection of docking poses, the application of Quantum mechanics(QM) in docking, and covalent docking.

EXPERT OPINION

There are several issues being worked on in recent years that will lead to important breakthroughs in molecular docking methods in the near future These developments are related to more efficient exploration of large datasets and receptor conformations, advances in electronic description, and the use of structural information for guiding the selection of results.

Isodeoxyelephantopin Inactivates Thioredoxin Reductase 1 and Activates ROS-Mediated JNK Signaling Pathway to Exacerbate Cisplatin Effectiveness in Human Colon Cancer Cells

Colon cancer is one of the leading causes of cancer-related death in the world. The development of new drugs and therapeutic strategies for patients with colon cancer are urgently needed. Isodeoxyelephantopin (ESI), a sesquiterpene lactone isolated from the medicinal plant Elephantopus scaber L., has been reported to exert antitumor effects on several cancer cells. However, the molecular mechanisms underlying the action of ESI is still elusive. In the present study, we found that ESI potently suppressed cell proliferation in human colon cancer cells. Furthermore, our results showed that ESI treatment markedly increased cellular reactive oxygen species (ROS) levels by inhibiting thioredoxin reductase 1 (TrxR1) activity, which leads to activation of the JNK signaling pathway and eventually cell death in HCT116 and RKO cells. Importantly, we found that ESI markedly enhanced cisplatin-induced cytotoxicity in HCT116 and RKO cells. Combination of ESI and cisplatin significantly increased the production of ROS, resulting in activation of the JNK signaling pathway in HCT116 and RKO cells. In vivo, we found that ESI combined with cisplatin significantly suppressed tumor growth in HCT116 xenograft models. Together, our study provide a preclinical proof-of-concept for ESI as a potential strategy for colon cancer treatment.

ST1926 inhibits glioma progression through regulating mitochondrial complex II

The antitumor activity of atypical adamantyl retinoid ST1926 has been frequently reported in cancer studies; nevertheless, its effect on glioma has not been fully understood. Mitochondria are critical in regulating tumorigenesis and are defined as a promising target for anti-tumor therapy. In the present study, we found that ST1926 might be a mitochondria-targeting anti-glioma drug. ST1926 showed significantly inhibitory role in the viability of glioma cells mainly through inducing apoptosis and autophagy. The results showed that ST1926 alleviated mitochondria-regulated bioenergetics in glioma cells via reducing ATP production and promoting reactive oxygen species production. Importantly, ST1926 significantly impaired complex II (CII) function, which was associated with the inhibition of succinate dehydrogenase (SDH) activity. In addition, the effects of ST1926 on the induction of apoptosis and ROS were further promoted by the treatment of CII inhibitors, including TTFA and 3-NPA. Furthermore, the in vivo experiments confirmed the role of ST1926 in suppressing xenograft tumor growth with few toxicity. Therefore, ST1926 might be an effective anti-glioma drug through targeting CII.

Hydroethanolic Extract of Solanum paniculatum L. Fruits Modulates ROS and Cytokine in Human Cell Lines

Solanum paniculatum L. or popularly known as “jurubeba” is an herbal medicinal plant. A few studies have investigated its biological effects; however, research aimed at elucidating the redox balance effects from its fruits has not been reported so far. ROS interplays in various fields of medicine such as chemotherapy. Here, we evaluated antioxidant and inflammatory activities of the hydroethanolic extract of Solanum Paniculatum L. (HESPL) fruits in breast cancer cells, as well as its phytochemical profile. The antioxidant profile (carotenoids and phenolic compounds) was obtained by HPLC-DAD-UV and HPLC-APCI-MS. Cancer cell lines and human vein endothelial cells (HUVECs) were cultivated and treated with 1.87-30 μg/mL of HESPL for 24 hrs. Cytotoxicity, oxidative, and inflammation biomarkers were evaluated. The dose of 30 μg/mL of the HESPL extract presented cytotoxicity in the MCF-7 cell line. However, for MDA-MB-231, the cytotoxicity was observed in the dose of 1.87 g/mL. The 1.87 μg/mL and 3.75 μg/mL doses decreased the concentration of IL-6 in MCF-7 cells. In the MDA-MB-231 cells, the HESPL did not decrease the IL-6 concentration; however, in the doses of 15 and 30 μg/mL, an increase in this parameter was observed. The HESPL increased IL-1β concentration in HUVECs. The ROS level in MCF-7 was elevated only at the 30 μg/ml dose. Regarding MDA-MB-231, HESPL promoted increased ROS levels at all doses tested. HUVEC showed no increase in ROS under any dose. HESPL treatment may modulate cytotoxicity, ROS, and cytokine levels due to its phytochemical profile, and it has shown an antioxidant or anti-inflammatory effect.

Epigenetics/epigenomics and prevention by curcumin of early stages of inflammatory-driven colon cancer

Colorectal cancer (CRC) is associated with significant morbidity and mortality in the US and worldwide. CRC is the second most common cancer-related death in both men and women globally. Chronic inflammation has been identified as one of the major risk factors of CRC. It may drive genetic and epigenetic/epigenomic alterations, such as DNA methylation, histone modification, and non-coding RNA regulation. Current prevention modalities for CRC are limited and some treatment regimens such as use the nonsteroidal anti-inflammatory drug aspirin may have severe side effects, namely gastrointestinal ulceration and bleeding. Therefore, there is an urgent need of developing alternative strategies. Recently, increasing evidence suggests that several dietary cancer chemopreventive phytochemicals possess anti-inflammation and antioxidative stress activities, and may prevent cancers including CRC. Curcumin (CUR) is the yellow pigment that is found in the rhizomes of turmeric (Curcuma longa). Many studies have demonstrated that CUR exhibit strong anticancer, antioxidative stress, and anti-inflammatory activities by regulating signaling pathways, such as nuclear factor erythroid-2-related factor 2, nuclear factor-κB, and epigenetics/epigenomics pathways of histones modifications, and DNA methylation. In this review, we will discuss the latest evidence in epigenetics/epigenomics alterations by CUR in CRC and their potential contribution in the prevention of CRC.