Nrf2-dependent suppression of azoxymethane/dextran sulfate sodium-induced colon carcinogenesis by the cinnamon-derived dietary factor cinnamaldehyde

Naturally-derived modulators of the Nrf2 pathway and their roles in the intervention of diseases

Cumulative evidence has verified that persistent oxidative stress is involved in the development of various chronic diseases, including pulmonary, neurodegenerative, kidney, cardiovascular, and liver diseases, as well as cancers. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a pivotal role in regulating cellular oxidative stress and inflammatory reactions, making it a focal point for disease prevention and treatment strategies. Natural products are essential resources for discovering leading molecules for new drug research and development. In this review, we comprehensively outlined the progression of the knowledge on the Nrf2 pathway, Nrf2 activators in clinical trials, the naturally-derived Nrf2 modulators (particularly from 2014-present), as well as their effects on the pathogenesis of chronic diseases.

Cinnamaldehyde: Pharmacokinetics, anticancer properties and therapeutic potential (Review)

Cancer incidence is increasing globally, presenting a growing public health challenge. While anticancer drugs are crucial in treatment, their limitations, including poor targeting ability and high toxicity, hinder effectiveness and patient safety, requiring relentless scientific research and technological advancements to develop safer and more effective therapeutics. Cinnamaldehyde (CA), an active compound derived from the natural plant cinnamon, has garnered attention in pharmacological research due to its diverse therapeutic applications. CA has potential in treating a wide array of conditions, including cardiovascular diseases, diabetes, inflammatory disorders and various forms of cancer. The present review comprehensively summarizes the physicochemical and pharmacokinetic profiles of CA, and delves into the latest advancements in elucidating its potential mechanisms and targets across various cancer types. CA and its derivatives have antitumor effects, which encompass inhibiting cell proliferation, arresting the cell cycle, inducing apoptosis, limiting cell migration and invasion, and suppressing angiogenesis. Additionally, the present review explores targeted formulations of CA, laying a scientific foundation for further exploration of its implications in cancer prevention and treatment strategies.

Antioxidant and Anti-Apoptotic Neuroprotective Effects of Cinnamon in Imiquimod-Induced Lupus

BACKGROUND

Despite accumulating evidence correlating oxidative stress with lupus disease activity, the brain redox pathways are still poorly investigated. Cinnamomum cassia, a widely used spice with powerful antioxidant properties, could be a novel therapeutic candidate in lupus.

METHODS

C57BL/6J female mice were divided into five groups: sham, sham-cinnamon, lupus, lupus-cinnamon starting from induction, and lupus-cinnamon starting two weeks before induction. Lupus was induced by skin application on the right ear with 1.25 mg of 5% imiquimod cream three times per week for six weeks. Cinnamomum cassia was given orally, five days per week, at 200 mg/kg.

RESULTS

Concomitant to TLR7-MYD88 pathway activation, the p-NRF2/NRF2 and p-FOXO3/FOXO3 ratios were increased in the hippocampus and alleviated by cinnamon treatment. BCL-2 positivity was enhanced in hippocampal neurons and reversed only by preventive cinnamon administration. In vitro, exposure of hippocampal cells to the plasma of different groups induced a surge in oxidative stress. This was associated with an increased t-BID/BID ratio. Cinnamon treatment, particularly in the preventive arm, normalized these modifications.

CONCLUSIONS

Our study shows a neuroprotective effect of cinnamon by rescuing brain redox and apoptosis homeostasis in lupus, paving the way for its use as a natural therapeutic compound in the clinical management of lupus.

The role and mechanism of cinnamaldehyde in cancer

As cancer continues to rise globally, there is growing interest in discovering novel methods for prevention and treatment. Due to the limitations of traditional cancer therapies, there has been a growing emphasis on investigating herbal remedies and exploring their potential synergistic effects when combined with chemotherapy drugs. Cinnamaldehyde, derived from cinnamon, has gained significant attention for its potential role in cancer prevention and treatment. Extensive research has demonstrated that cinnamaldehyde exhibits promising anticancer properties by modulating various cellular processes involved in tumor growth and progression. However, challenges and unanswered questions remain regarding the precise mechanisms for its effective use as an anticancer agent. This article aims to explore the multifaceted effects of cinnamaldehyde on cancer cells and shed light on these existing issues. Cinnamaldehyde has diverse anti-cancer mechanisms, including inducing apoptosis by activating caspases and damaging mitochondrial function, inhibiting tumor angiogenesis, anti-proliferation, anti-inflammatory and antioxidant. In addition, cinnamaldehyde also acts as a reactive oxygen species scavenger, reducing oxidative stress and preventing DNA damage and genomic instability. This article emphasizes the promising therapeutic potential of cinnamaldehyde in cancer treatment and underscores the need for future research to unlock novel mechanisms and strategies for combating cancer. By providing valuable insights into the role and mechanism of cinnamaldehyde in cancer, this comprehensive understanding paves the way for its potential as a novel therapeutic agent. Overall, cinnamaldehyde holds great promise as an anticancer agent, and its comprehensive exploration in this article highlights its potential as a valuable addition to cancer treatment options.

Hyaluronic acid-based multifunctional bio-active coating integrated with cinnamaldehyde/hydroxypropyl-β-cyclodextrin inclusion complex for fruit preservation

Natural preservatives such as cinnamaldehyde (CIN) are garnering increasing interest to replace their synthetic counterparts in maintaining fruit freshness and safety. However, their long-term effectiveness and widespread application have been greatly limited due to high volatility and potent aroma. To address these challenges, we developed a viable and simple strategy to prepare a multifunctional active coating for fruit preservation by incorporating host-guest inclusion complex of CIN and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) CIN@HP-β-CD into hyaluronic acid (HA), a natural polysaccharide with exceptional film-forming properties. The as-prepared HA/CIN@HP-β-CD coatings exhibited universal surface affinity, excellent antimicrobial performance, and satisfactory antioxidant properties with no potential toxicity. Release kinetic studies have demonstrated that CIN in the coating is continuously and slowly released. Furthermore, freshness preservation experiments on bananas and fresh-cut apples demonstrated that the developed coating is effective in preserving the color of fruit, decreasing the weight loss rate, preventing the microorganism's growth, and significantly extending the period of freshness, exhibiting the potential for application in fruit preservation.

Huangqin Decoction Delays Progress of Colitis-Associated Carcinogenesis by Regulating Nrf2/HO-1 Antioxidant Signal Pathway in Mice

OBJECTIVE

To investigate the effect of Huangqin Decoction (HQD) on nuclear factor erythroid 2 related-factor 2 (Nrf2)/heme oxygenase (HO-1) signaling pathway by inducing the colitis-associated carcinogenesis (CAC) model mice with azoxymethane (AOM)/dextran sodium sulfate (DSS).

METHODS

The chemical components of HQD were analyzed by liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS/MS) to determine the molecular constituents of HQD. Totally 48 C57BL/6J mice were randomly divided into 6 groups by a random number table, including control, model (AOM/DSS), mesalazine (MS), low-, medium-, and high-dose HQD (HQD-L, HQD-M, and HQD-H) groups, 8 mice in each group. Except for the control group, the mice in the other groups were intraperitoneally injected with AOM (10 mg/kg) and administrated with 2.5% DSS orally for 1 week every two weeks (totally 3 rounds of DSS) to construct a colitis-associated carcinogenesis mouse model. The mice in the HQD-L, HQD-M and HQD-H groups were given HQD by gavage at doses of 2.925, 5.85, and 11.7 g/kg, respectively; the mice in the MS group was given a suspension of MS at a dose of 0.043 g/kg (totally 11 weeks). The serum levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured by enzyme-linked immunosorbent assay. The mRNA and protein expression levels of Nrf2, HO-1, and inhibitory KELCH like ECH-related protein 1 (Keap1) in colon tissue were detected by quantitative real-time PCR, immunohistochemistry, and Western blot, respectively.

RESULTS

LC-Q-TOF-MS/MS analysis revealed that the chemical constituents of HQD include baicalin, paeoniflorin, and glycyrrhizic acid. Compared to the control group, significantly higher MDA levels and lower SOD levels were observed in the model group (P<0.05), whereas the expressions of Nrf2 and HO-1 were significantly decreased, and the expression of Keap1 increased (P<0.01). Compared with the model group, serum MDA level was decreased and SOD level was increased in the HQD-M, HQD-H and MS groups (P<0.05). Higher expressions of Nrf2 and HO-1 were observed in the HQD groups.

CONCLUSION

HQD may regulate the expression of Nrf2 and HO-1 in colon tissue, reduce the expression of MDA and increase the expression of SOD in serum, thus delaying the progress of CAC in AOM/DSS mice.

The role of bixin as antioxidant, anti-inflammatory, anticancer, and skin protecting natural product extracted from Bixa orellana L

Since long, medicinal plants or herbs are being used in different traditional treatment systems as therapeutic agents to treat a variety of illnesses. Bixa orellana L., an medicinal plant (family: Bixaceae), is an Ayurvedic herb used to treat dyslipidemia, diarrhoea, and hepatitis since ancient times. B. orellana L., seeds contain an orange-red coloured component known as bixin (C25H30O4), which constitutes 80% of the extract.Chemically, bixin is a natural apocarotenoid, biosynthesized through the oxidative degradation of C40 carotenoids. Bixin helps to regulate the Nrf2/MyD88/TLR4 and TGF-1/PPAR-/Smad3 pathways, which further give it antifibrosis, antioxidant, and anti-inflammatory properties. This current review article presents a comprehensive review of bixin as an anti-inflammatory, antioxidant, anticancer,and skin protecting natural product. In addition, the biosynthesis and molecular target of bixin, along with bixin extraction techniques, are also presented.

Cinnamaldehyde-Rich Cinnamon Extract Induces Cell Death in Colon Cancer Cell Lines HCT 116 and HT-29

Cinnamon is a natural spice with a wide range of pharmacological functions, including anti-microbial, antioxidant, and anti-tumor activities. The aim of this study is to investigate the effects of cinnamaldehyde-rich cinnamon extract (CRCE) on the colorectal cancer cell lines HCT 116 and HT-29. The gas chromatography mass spectrometry analysis of a lipophilic extract of cinnamon revealed the dominance of trans-cinnamaldehyde. Cells treated with CRCE (10-60 µg/mL) showed significantly decreased cell viability in a time- and dose-dependent manner. We also observed that cell proliferation and migration capacity were inhibited in CRCE-treated cells. In addition, a remarkable increase in the number of sub-G₁-phase cells was observed with arrest at the G₂ phase by CRCE treatment. CRCE also induced mitochondrial stress, and finally, CRCE treatment resulted in activation of apoptotic proteins Caspase-3, -9, and PARP and decreased levels of mu-2-related death-inducing gene protein expression with BH3-interacting domain death agonist (BID) activation.

Reactive Oxygen Species and NRF2 Signaling, Friends or Foes in Cancer?

The imbalance between reactive oxygen species (ROS) production and clearance causes oxidative stress and ROS, which play a central role in regulating cell and tissue physiology and pathology. Contingent upon concentration, ROS influence cancer development in contradictory ways, either stimulating cancer survival and growth or causing cell death. Cells developed evolutionarily conserved programs to sense and adapt redox the fluctuations to regulate ROS as either signaling molecules or toxic insults. The transcription factor nuclear factor erythroid 2-related factor 2 (NRF2)-KEAP1 system is the master regulator of cellular redox and metabolic homeostasis. NRF2 has Janus-like roles in carcinogenesis and cancer development. Short-term NRF2 activation suppresses tissue injury, inflammation, and cancer initiation. However, cancer cells often exhibit constitutive NRF2 activation due to genetic mutations or oncogenic signaling, conferring advantages for cancer cells' survival and growth. Emerging evidence suggests that NRF2 hyperactivation, as an adaptive cancer phenotype under stressful tumor environments, regulates all hallmarks of cancer. In this review, we summarized the source of ROS, regulation of ROS signaling, and cellular sensors for ROS and oxygen (O₂), we reviewed recent progress on the regulation of ROS generation and NRF2 signaling with a focus on the new functions of NRF2 in cancer development that reach beyond what we originally envisioned, including regulation of cancer metabolism, autophagy, macropinocytosis, unfolded protein response, proteostasis, and circadian rhythm, which, together with anti-oxidant and drug detoxification enzymes, contributes to cancer development, metastasis, and anticancer therapy resistance.

Effects of Medicinal Plants and Phytochemicals in Nrf2 Pathways during Inflammatory Bowel Diseases and Related Colorectal Cancer: A Comprehensive Review

Inflammatory bowel diseases (IBDs) are related to nuclear factor erythroid 2-related factor 2 (Nrf2) dysregulation. In vitro and in vivo studies using phytocompounds as modulators of the Nrf2 signaling in IBD have already been published. However, no existing review emphasizes the whole scenario for the potential of plants and phytocompounds as regulators of Nrf2 in IBD models and colitis-associated colorectal carcinogenesis. For these reasons, this study aimed to build a review that could fill this void. The PubMed, EMBASE, COCHRANE, and Google Scholar databases were searched. The literature review showed that medicinal plants and phytochemicals regulated the Nrf2 on IBD and IBD-associated colorectal cancer by amplifying the expression of the Nrf2-mediated phase II detoxifying enzymes and diminishing NF-κB-related inflammation. These effects improve the bowel environment, mucosal barrier, colon, and crypt disruption, reduce ulceration and microbial translocation, and consequently, reduce the disease activity index (DAI). Moreover, the modulation of Nrf2 can regulate various genes involved in cellular redox, protein degradation, DNA repair, xenobiotic metabolism, and apoptosis, contributing to the prevention of colorectal cancer.

Role of NRF2 in Colorectal Cancer Prevention and Treatment

Nuclear factor erythroid 2-related factor 2 (NRF2) is a basic leucine zipper protein that participates in a complex regulatory network in the body. The activation of NRF2 can prevent and treat colorectal cancer (CRC). A variety of natural compounds can activate NRF2 to inhibit oxidative stress and inflammation to prevent the occurrence and development of CRC, inhibit the proliferation of CRC cells and induce their apoptosis. However, some studies have also shown that it also has negative effects on CRC, such as overexpression of NRF2 can promote the growth of colorectal tumors and increase the drug resistance of chemotherapeutic drugs such as 5-fluorouracil and oxaliplatin. Therefore, inhibition of NRF2 can also be helpful in the treatment of CRC. In this study, we analyze the current research progress of NRF2 in CRC from various aspects to provide new ideas for prevention and treatment based on the NRF2 signaling pathway in CRC.

The molecular biology and therapeutic potential of Nrf2 in leukemia

NF-E2-related factor 2 (Nrf2) transcription factor has contradictory roles in cancer, which can act as a tumor suppressor or a proto-oncogene in different cell conditions (depending on the cell type and the conditions of the cell environment). Nrf2 pathway regulates several cellular processes, including signaling, energy metabolism, autophagy, inflammation, redox homeostasis, and antioxidant regulation. As a result, it plays a crucial role in cell survival. Conversely, Nrf2 protects cancerous cells from apoptosis and increases proliferation, angiogenesis, and metastasis. It promotes resistance to chemotherapy and radiotherapy in various solid tumors and hematological malignancies, so we want to elucidate the role of Nrf2 in cancer and the positive point of its targeting. Also, in the past few years, many studies have shown that Nrf2 protects cancer cells, especially leukemic cells, from the effects of chemotherapeutic drugs. The present paper summarizes these studies to scrutinize whether targeting Nrf2 combined with chemotherapy would be a therapeutic approach for leukemia treatment. Also, we discussed how Nrf2 and NF-κB work together to control the cellular redox pathway. The role of these two factors in inflammation (antagonistic) and leukemia (synergistic) is also summarized.

Corylin from Psoralea fructus (Psoralea corylifolia L.) protects against UV-induced skin aging by activating Nrf2 defense mechanisms

Oxidative stress damage can lead to premature skin aging or age-related skin disorders. Therefore, strategies to improve oxidative stress-induced aging are needed to protect the skin and to treat skin diseases. This study aimed to determine whether the flavonoid corylin derived from Psoralea corylifolia can prevent UV-induced skin aging and if so, to explore the potential molecular mechanisms. We found that corylin potently blocked UV-induced skin photoaging in mice by reducing oxidative stress and increasing the nuclear expression of nuclear factor-erythroid factor 2-related factor 2 Nrf2. We also found that corylin stimulated Nrf2 translocation into the nucleus and increased the delivery of its target antioxidant genes together with Kelch-like ECH-associated protein 1 (Keap1) to dissociate Nrf2. These findings indicate that corylin could prevent skin aging by inhibiting oxidative stress via Keap1-Nrf2 in mouse cells. Thus, Nrf2 activation might be a therapeutic target for preventing skin aging or skin diseases caused by aging. Our findings also provided evidence that warrants the further investigation of plant ingredients to facilitate the discovery of novel therapies targeting skin aging.

GSTM3 deficiency impedes DNA mismatch repair to promote gastric tumorigenesis via CAND1/NRF2-KEAP1 signaling

Gastric cancer (GC) is one of the most severe gastric diseases worldwide. However, the molecular basis that drives tumorigenesis and progression is not completely understood, which hinders the efficacy and development of therapeutic options. Glutathione-S-transferases (GSTs) are a group of phase II detoxification enzymes that maintain redox homeostasis; however, their roles in cancers are not well defined. Here, we revealed that the expression of GST family members is significantly impaired in GC tissues. Glutathione-S-transferase mu 3 (GSTM3), a member of GST family, is dramatically downregulated in cancerous tissues and has been identified as an independent prognostic factor in GC associated with tumor differentiation, inhibiting GC cell proliferation and migration in vitro and in vivo. Mechanistically, GSTM3 is transcriptionally activated by NRF2/KEAP1 signaling. As a feedback loop, GSTM3 binds to Cullin-associated and neddylation-dissociated 1 protein (CAND1), an exchange factor for integrating Kelch-like ECH-associated protein 1 (KEAP1) into Cul3-RING ubiquitin ligases (CRL3), to disrupt nuclear factor-erythroid factor 2-related factor 2 (NRF2)/KEAP1 binding and prevent NRF2 ubiquitination and degradation, leading to its activation. A deficiency in glutathione S-Transferase Mu 3 (GSTM3) reduces DNA mismatch repair (MMR) gene expression and increases mutagenesis via CAND1/NRF2 binding. Importantly, GSTM3/NRF2 and KEAP1 were negatively and positively associated with the genomic signature for microsatellite instability, respectively. Clinically, GSTM3, NRF2, and MutS homolog 6 (MSH6) were positively correlated in the GC specimens. This study uncovered a reciprocal regulation between GSTM3 and NRF2 and established a functional and clinical link between GSTM3-NRF2/KEAP1 and MMR during GC cell proliferation and progression, thus providing potential therapeutic targets for GC.

Hepatoprotection of Cinnamomum burmannii ethanolic extract against high-fat and cholesterol diet in Sprague–Dawley rats (Rattus norvegicus)

Background and Aim:

The pathogenesis of non-alcoholic steatohepatitis involves non-alcoholic fatty liver, oxidative stress, inflammation, and fibrosis. Although the long-term use of cinnamon bark in larger doses can negatively affect good health, proper use of its extracts effectively and efficiently improves health. Therefore, this study aimed to determine the minimal dose of Cinnamomum Burmannii extract through its activity in inhibiting oxidative stress in rats’ livers treated with a high-fat and cholesterol diet (HFCD).

Materials and Methods:

Forty-two Sprague–Dawley rats (Rattus norvegicus), weighing 200-250 g body weight (BW), were divided into seven treatment groups with six replications: Normal, HFCD, atorvastatin, quercetin, and C. burmannii ethanol extract group, after which they were administered different dosages (i.e., 100, 200, and 300 mg/kg BW). Except for the normal group, rats were concomitantly administered HFCD with each treatment for 21 days. Then, their malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity were assessed using colorimetry. However, their steatosis levels were determined based on histological preparations with hematoxylin-eosin staining.

Results:

Duncan’s multiple range test (DMRT) results indicated that all treatments had a significantly lower MDA than HFCD and normal rats (a=0.01). DMRT results also showed that treating with the C. burmannii ethanol extract at all dosages resulted in a significantly higher SOD activity level in HFCD rats than those treated with quercetin and atorvastatin (a=0.01). Furthermore, results showed that treatment with C. burmannii extracts at a dosage of 300 mg/kg BW incredibly maintained SOD activity as effective as quercetin, atorvastatin, and normal rats. Besides, while steatohepatitis levels of C. burmannii ethanol extract at dosages of 200 and 300 mg/kg BW commensurated with normal rats, steatohepatitis levels were significantly lower than those administered other concentrations or treatments (a=0.05).

Conclusion:

Ethanolic C. burmannii extracts protected the liver by regulating oxidative stress. Therefore, a 200 mg/kg BW dose is proposed as the minimal hepatoprotection dose to prevent fatty liver formation.

Combinatorial Effects of the Natural Products Arctigenin, Chlorogenic Acid, and Cinnamaldehyde Commit Oxidation Assassination on Breast Cancer Cells

Major obstacles in current breast cancer treatment efficacy include the ability of breast cancer cells to develop resistance to chemotherapeutic drugs and the off-target cytotoxicity of these drugs on normal cells, leading to debilitating side effects. One major difference between cancer and normal cells is their metabolism, as cancer cells acquire glycolytic and mitochondrial metabolism alterations throughout tumorigenesis. In this study, we sought to exploit this metabolic difference by investigating alternative breast cancer treatment options based on the application of phytochemicals. Herein, we investigated three phytochemicals, namely cinnamaldehyde (CA), chlorogenic acid (CGA), and arctigenin (Arc), regarding their anti-breast-cancer properties. These phytochemicals were administered alone or in combination to MCF-7, MDA-MB-231, and HCC1419 breast cancer or normal MCF-10A and MCF-12F breast cells. Overall, our results indicated that the combination treatments showed stronger inhibitory effects on breast cancer cells versus single treatments. However, only treatments with CA (35 μM), CGA (250 μg/mL), and the combination of CA + CGA (35 μM + 250 μg/mL) showed no significant cytotoxic effects on normal mammary epithelial cells, suggesting that Arc was the driver of normal cell cytotoxicity in all other treatments. CA + CGA and, to a lesser extent, CGA alone effectively induced breast cancer cell death accompanied by decreases in mitochondrial membrane potential, increased mitochondrial superoxide, reduced mitochondrial and glycolytic ATP production, and led to significant changes in cellular and mitochondrial morphology. Altogether, the combination of CA + CGA was determined as the best anti-breast-cancer treatment strategy due to its strong anti-breast-cancer effects without strong adverse effects on normal mammary epithelial cells. This study provides evidence that targeting the mitochondria may be an effective anticancer treatment, and that using phytochemicals or combinations thereof offers new approaches in treating breast cancer that significantly reduce off-target effects on normal cells.

miR-196a Upregulation Contributes to Gefitinib Resistance through Inhibiting GLTP Expression

Tyrosine kinase inhibitor (TKI) therapy has greatly improved lung cancer survival in patients with epidermal growth factor receptor (EGFR) mutations. However, the development of TKI-acquired resistance is the major problem to be overcome. In this study, we found that miR-196a expression was greatly induced in gefitinib-resistant lung cancer cells. To understand the role and mechanism of miR-196a in TKI resistance, we found that miR-196a-forced expression alone increased cell resistance to gefitinib treatment in vitro and in vivo by inducing cell proliferation and inhibiting cell apoptosis. We identified the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) bound to the promoter region of miR-196a and induced miR-196a expression at the transcriptional level. NRF2-forced expression also significantly increased expression levels of miR-196a, and was an upstream inducer of miR-196a to mediate gefitinib resistance. We also found that glycolipid transfer protein (GLTP) was a functional direct target of miR-196a, and downregulation of GLTP by miR-196a was responsible for gefitinib resistance. GLTP overexpression alone was sufficient to increase the sensitivity of lung cancer cells to gefitinib treatment. Our studies identified a new role and mechanism of NRF2/miR-196a/GLTP pathway in TKI resistance and lung tumor development, which may be used as a new biomarker (s) for TKI resistance or as a new therapeutic target in the future.

NRF2: KEAPing Tumors Protected

The Kelch-like ECH-associated protein 1 (KEAP1)/nuclear factor erythroid 2-related factor 2 (NRF2) pathway plays a physiologic protective role against xenobiotics and reactive oxygen species. However, activation of NRF2 provides a powerful selective advantage for tumors by rewiring metabolism to enhance proliferation, suppress various forms of stress, and promote immune evasion. Genetic, epigenetic, and posttranslational alterations that activate the KEAP1/NRF2 pathway are found in multiple solid tumors. Emerging clinical data highlight that alterations in this pathway result in resistance to multiple therapies. Here, we provide an overview of how dysregulation of the KEAP1/NRF2 pathway in cancer contributes to several hallmarks of cancer that promote tumorigenesis and lead to treatment resistance. SIGNIFICANCE: Alterations in the KEAP1/NRF2 pathway are found in multiple cancer types. Activation of NRF2 leads to metabolic rewiring of tumors that promote tumor initiation and progression. Here we present the known alterations that lead to NRF2 activation in cancer, the mechanisms in which NRF2 activation promotes tumors, and the therapeutic implications of NRF2 activation.

Traditional Herbal Medicine: A Potential Therapeutic Approach for Adjuvant Treatment of Non-small Cell Lung Cancer in the Future

Lung carcinoma is the primary reason for cancer-associated mortality, and it exhibits the highest mortality and incidence in developed and developing countries. Non-small cell lung cancer (NSCLC) and SCLC are the 2 main types of lung cancer, with NSCLC contributing to 85% of all lung carcinoma cases. Conventional treatment mainly involves surgery, chemoradiotherapy, and immunotherapy, but has a dismal prognosis for many patients. Therefore, identifying an effective adjuvant therapy is urgent. Historically, traditional herbal medicine has been an essential part of complementary and alternative medicine, due to its numerous targets, few side effects and substantial therapeutic benefits. In China and other East Asian countries, traditional herbal medicine is increasingly popular, and is highly accepted by patients as a clinical adjuvant therapy. Numerous studies have reported that herbal extracts and prescription medications are effective at combating tumors. It emphasizes that, by mainly regulating the P13K/AKT signaling pathway, the Wnt signaling pathway, and the NF-κB signaling pathway, herbal medicine induces apoptosis and inhibits the proliferation and migration of tumor cells. The present review discusses the anti-NSCLC mechanisms of herbal medicines and provides options for future adjuvant therapy in patients with NSCLC.

Matlodextrin-cinnamon essential oil nanoformulation as a potent protective against titanium nanoparticles-induced oxidative stress, genotoxicity, and reproductive disturbances in male mice

Recently, bio-nanofabrication becomes one of the widest methods for synthesizing nanoparticles (NPs); however, there is scanty literature exploring the toxicity of these green NPs against living organisms. This study aimed to evaluate the potential protective role of encapsulated cinnamon oil (ECO) against titanium oxide nanoparticle (TiO2NP)-induced oxidative stress, DNA damage, chromosomal aberration, and reproductive disturbances in male mice. Sixty male Balb/c mice were distributed into six groups treated orally for 3 weeks and included control group, TiO2NP-treated group (25 mg/kg b.w), ECO at low or high dose-treated groups (50 or 100 mg/kg b.w), and the groups that received TiO2NPs plus ECO at a low or high dose. The results of GC-MS revealed the isolation of 21 compounds and the majority was cinnamaldehyde. The average size zeta potential of TiO2NPs and ECO were 28.9 and 321 nm and -33.97 and -17.35 mV, respectively. TiO2NP administration induced significant changes in liver and kidney function, decreased antioxidant capacity, and increased oxidative stress markers in liver and kidney, DNA damage in the hepatocytes, the number of chromosomal aberrations in the bone marrow and germ cells, and sperm abnormalities along with histological changes in the liver, kidney, and testis. Co-administration of TiO2NPs and ECO could alleviate these disturbances in a dose-dependent manner. It could be concluded that ECO is a promising and safe candidate for the protection against the health hazards of TiO2NPs.

The intricacies of NRF2 regulation in cancer

The complex role of NRF2 in the context of cancer continues to evolve. As a transcription factor, NRF2 regulates various genes involved in redox homeostasis, protein degradation, DNA repair, and xenobiotic metabolism. As such, NRF2 is critical in preserving cell function and viability, particularly during stress. Importantly, NRF2 itself is regulated via a variety of mechanisms, and the mode of NRF2 activation often dictates the duration of NRF2 signaling and its role in either preventing cancer initiation or promoting cancer progression. Herein, different modes of NRF2 regulation, including oxidative stress, autophagy dysfunction, protein-protein interactions, and epigenetics, as well as pharmacological modulators targeting this cascade in cancer, are explored. Specifically, how the timing and duration of these different mechanisms of NRF2 induction affect tumor initiation, progression, and metastasis are discussed. Additionally, progress in the discovery and development of NRF2 inhibitors for the treatment of NRF2-addicted cancers is highlighted, including modulators that inhibit specific NRF2 downstream targets. Overall, a better understanding of the intricate nature of NRF2 regulation in specific cancer contexts should facilitate the generation of novel therapeutics designed to not only prevent tumor initiation, but also halt progression and ultimately improve patient wellbeing and survival.

Delivery of Cinnamic Aldehyde Antioxidant Response Activating nanoParticles (ARAPas) for Vascular Applications

Selective delivery of nuclear factor erythroid 2-related factor 2 (Nrf2) activators to the injured vasculature at the time of vascular surgical intervention has the potential to attenuate oxidative stress and decrease vascular smooth muscle cell (VSMC) hyperproliferation and migration towards the inner vessel wall. To this end, we developed a nanoformulation of cinnamic aldehyde (CA), termed Antioxidant Response Activating nanoParticles (ARAPas), that can be readily loaded into macrophages ex vivo. The CA-ARAPas-macrophage system was used to study the effects of CA on VSMC in culture. CA was encapsulated into a pluronic micelle that was readily loaded into both murine and human macrophages. CA-ARAPas inhibits VSMC proliferation and migration, and activates Nrf2. Macrophage-mediated transfer of CA-ARAPas to VSMC is evident after 12 h, and Nrf2 activation is apparent after 24 h. This is the first report, to the best of our knowledge, of CA encapsulation in pluronic micelles for macrophage-mediated delivery studies. The results of this study highlight the feasibility of CA encapsulation and subsequent macrophage uptake for delivery of cargo into other pertinent cells, such as VSMC.

Activation of Nrf2 signaling pathway by natural and synthetic chalcones: a therapeutic road map for oxidative stress

Introduction:Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway plays a key role in diverse gene expressions responsible for protection against oxidative stress and xenobiotics. Chalcones with a common chemical scaffold of 1,3-diaryl-2- propen-1-one, are abundantly present in nature with a wide variety of pharmacological properties. This review will discuss the interactions of natural and synthetic chalcones with Nrf2 signaling.Areas covered:Chalcones are reportedly found to activate Nrf2 signaling pathway, expression of Nrf2-regulated antioxidant genes, induce cytoprotective proteins and upregulate multidrug resistance-associated proteins. Chalcones being soft electrophiles are less prone to hostile off-target effects and unlikely to induce carcinogenicity and mutagenicity. Furthermore, their low toxicity, structural diversity, feasibility in structural reorganization and the presence of α,β-unsaturated carbonyl group which makes them suitable drug candidates targeting Nrf2-dependent diseases.Expert opinion:Nrf2-Keap1 signaling pathway plays a central role in redox signaling. However, available therapeutic agents for Nrf2 activation have limited practical applications due to their associated risks, relatively low efficacy and bioavailability. The designing and fabrication of new chemical entities with chalcone scaffold-based Michael acceptor mechanism should be aimed as potential therapeutic Nrf2 activators to target oxidative stress and inflammation-mediated diseases such as atherosclerosis, Parkinson's disease and many more.

Deuterium Oxide (D2O) Induces Early Stress Response Gene Expression and Impairs Growth and Metastasis of Experimental Malignant Melanoma

There are two stable isotopes of hydrogen, protium (1H) and deuterium (2H; D). Cellular stress response dysregulation in cancer represents both a major pathological driving force and a promising therapeutic target, but the molecular consequences and potential therapeutic impact of deuterium (2H)-stress on cancer cells remain largely unexplored. We have examined the anti-proliferative and apoptogenic effects of deuterium oxide (D2O; 'heavy water') together with stress response gene expression profiling in panels of malignant melanoma (A375V600E, A375NRAS, G361, LOX-IMVI), and pancreatic ductal adenocarcinoma (PANC-1, Capan-2, or MIA PaCa-2) cells with inclusion of human diploid Hs27 skin fibroblasts. Moreover, we have examined the efficacy of D2O-based pharmacological intervention in murine models of human melanoma tumor growth and metastasis. D2O-induction of apoptosis was substantiated by AV-PI flow cytometry, immunodetection of PARP-1, and pro-caspase 3 cleavage, and rescue by pan-caspase inhibition. Differential array analysis revealed early modulation of stress response gene expression in both A375 melanoma and PANC-1 adenocarcinoma cells elicited by D2O (90%; ≤6 h) (upregulated: CDKN1A, DDIT3, EGR1, GADD45A, HMOX1, NFKBIA, or SOD2 (up to 9-fold; p < 0.01)) confirmed by independent RT-qPCR analysis. Immunoblot analysis revealed rapid onset of D2O-induced stress response phospho-protein activation (p-ERK, p-JNK, p-eIF2α, or p-H2AX) or attenuation (p-AKT). Feasibility of D2O-based chemotherapeutic intervention (drinking water (30% w/w)) was demonstrated in a severe combined immunodeficiency (SCID) mouse melanoma metastasis model using luciferase-expressing A375-Luc2 cells. Lung tumor burden (visualized by bioluminescence imaging) was attenuated by D2O, and inhibition of invasiveness was also confirmed in an in vitro Matrigel transwell invasion assay. D2O supplementation also suppressed tumor growth in a murine xenograft model of human melanoma, and median survival was significantly increased without causing adverse effects. These data demonstrate for the first time that systemic D2O administration impairs growth and metastasis of malignant melanoma through the pharmacological induction of deuterium (2H)-stress.

Thymoquinone: A Tie-Breaker in SARS-CoV2-Infected Cancer Patients?

Since the beginning of the SARS-CoV-2(severe acute respiratory syndrome-coronavirus-2) pandemic, arace to develop a vaccine has been initiated, considering the massive and rather significant economic and healthcare hits that this virus has caused. The pathophysiology occurring following COVID-19(coronavirus disease-2019) infection has givenhints regarding the supportive and symptomatic treatments to establish for patients, as no specific anti-SARS-CoV-2 is available yet. Patient symptoms vary greatly and range from mild symptoms to severe fatal complications. Supportive treatments include antipyretics, antiviral therapies, different combinations of broad-spectrum antibiotics, hydroxychloroquine and plasma transfusion. Unfortunately, cancer patients are at higher risk of viral infection and more likely to develop serious complications due to their immunocompromised state, the fact that they are already administering multiple medications, as well as combined comorbidity compared to the general population. It may seem impossible to find a drug that possesses both potent antiviral and anticancer effects specifically against COVID-19 infection and its complications and the existing malignancy, respectively. Thymoquinone (TQ) is the most pharmacologically active ingredient in Nigella sativa seeds (black seeds); it is reported to have anticancer, anti-inflammatory and antioxidant effects in various settings. In this review, we will discuss the multiple effects of TQ specifically against COVID-19, its beneficial effects against COVID-19 pathophysiology and multiple-organ complications, its use as an adjuvant for supportive COVID-19 therapy and cancer therapy, and finally, its anticancer effects.

Genomic GLO1 deletion modulates TXNIP expression, glucose metabolism, and redox homeostasis while accelerating human A375 malignant melanoma tumor growth

Glyoxalase 1 (encoded by GLO1) is a glutathione-dependent enzyme detoxifying the glycolytic byproduct methylglyoxal (MG), an oncometabolite involved in metabolic reprogramming. Recently, we have demonstrated that GLO1 is overexpressed in human malignant melanoma cells and patient tumors and substantiated a novel role of GLO1 as a molecular determinant of invasion and metastasis in melanoma. Here, employing NanoString™ gene expression profiling (nCounter™ 'PanCancer Progression Panel'), we report that CRISPR/Cas 9-based GLO1 deletion from human A375 malignant melanoma cells alters glucose metabolism and redox homeostasis, observable together with acceleration of tumorigenesis. Nanostring™ analysis identified TXNIP (encoding thioredoxin-interacting protein), a master regulator of cellular energy metabolism and redox homeostasis, displaying the most pronounced expression change in response to GLO1 elimination, confirmed by RT-qPCR and immunoblot analysis. TXNIP was also upregulated in CRISPR/Cas9-engineered DU145 prostate carcinoma cells lacking GLO1, and treatment with MG or a pharmacological GLO1 inhibitor (TLSC702) mimicked GLO1_KO status, suggesting that GLO1 controls TXNIP expression through regulation of MG. GLO1_KO status was characterized by (i) altered oxidative stress response gene expression, (ii) attenuation of glucose uptake and metabolism with downregulation of gene expression (GLUT1, GFAT1, GFAT2, LDHA) and depletion of related key metabolites (glucose-6-phosphate, UDP-N-acetylglucosamine), and (iii) immune checkpoint modulation (PDL1). While confirming our earlier finding that GLO1 deletion limits invasion and metastasis with modulation of EMT-related genes (e.g. TGFBI, MMP9, ANGPTL4, TLR4, SERPINF1), we observed that GLO1_KO melanoma cells displayed a shortened population doubling time, cell cycle alteration with increased M-phase population, and enhanced anchorage-independent growth, a phenotype supported by expression analysis (CXCL8, CD24, IL1A, CDKN1A). Concordantly, an accelerated growth rate of GLO1_KO tumors, accompanied by TXNIP overexpression and metabolic reprogramming, was observable in a SCID mouse melanoma xenograft model, demonstrating that A375 melanoma tumor growth and metastasis can be dysregulated in opposing ways as a consequence of GLO1 elimination.

NRF2 and the Ambiguous Consequences of Its Activation during Initiation and the Subsequent Stages of Tumourigenesis

NF-E2 p45-related factor 2 (NRF2, encoded in the human by NFE2L2) mediates short-term adaptation to thiol-reactive stressors. In normal cells, activation of NRF2 by a thiol-reactive stressor helps prevent, for a limited period of time, the initiation of cancer by chemical carcinogens through induction of genes encoding drug-metabolising enzymes. However, in many tumour types, NRF2 is permanently upregulated. In such cases, its overexpressed target genes support the promotion and progression of cancer by suppressing oxidative stress, because they constitutively increase the capacity to scavenge reactive oxygen species (ROS), and they support cell proliferation by increasing ribonucleotide synthesis, serine biosynthesis and autophagy. Herein, we describe cancer chemoprevention and the discovery of the essential role played by NRF2 in orchestrating protection against chemical carcinogenesis. We similarly describe the discoveries of somatic mutations in NFE2L2 and the gene encoding the principal NRF2 repressor, Kelch-like ECH-associated protein 1 (KEAP1) along with that encoding a component of the E3 ubiquitin-ligase complex Cullin 3 (CUL3), which result in permanent activation of NRF2, and the recognition that such mutations occur frequently in many types of cancer. Notably, mutations in NFE2L2, KEAP1 and CUL3 that cause persistent upregulation of NRF2 often co-exist with mutations that activate KRAS and the PI3K-PKB/Akt pathway, suggesting NRF2 supports growth of tumours in which KRAS or PKB/Akt are hyperactive. Besides somatic mutations, NRF2 activation in human tumours can occur by other means, such as alternative splicing that results in a NRF2 protein which lacks the KEAP1-binding domain or overexpression of other KEAP1-binding partners that compete with NRF2. Lastly, as NRF2 upregulation is associated with resistance to cancer chemotherapy and radiotherapy, we describe strategies that might be employed to suppress growth and overcome drug resistance in tumours with overactive NRF2.

Natural Nrf2 Activators from Juices, Wines, Coffee, and Cocoa

Juices, wine, coffee, and cocoa are rich sources of natural polyphenolic compounds that have potent antioxidant activities proven by in vitro and in vivo studies. These polyphenolic compounds quench reactive oxygen and nitrogen species (RONS) or reactive free radicals and act as natural antioxidants which are also able to protect against reactive oxygen species (ROS)-mediated oxidative damage, which elevates cellular antioxidant capacity to induce antioxidant defense mechanisms by modulating transcription factors. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a transcription factor encoded in humans. It is activated as a result of oxidative stress and induces the expression of its target genes. This is one of the most important cellular defense mechanisms against oxidative stress. However, the oxidative stress alone is not enough to activate Nrf2. Hence phytochemicals, especially polyphenolics, act as natural Nrf2 activators. Herein, this review discusses the natural products identified in juices, coffee, cocoa and wines that modulate Nrf2 activity in cellular systems.

Promising targets of chrysin and daidzein in colorectal cancer: Amphiregulin, CXCL1, and MMP-9

Colorectal cancer is one of the primary causes of cancer-related mortality worldwide. The tumor microenvironment contains growth factors; inflammatory chemokines, matrix metalloproteinases, and pro-oxidants leading to cancer development and progression. Phytochemicals have been used as the main source of anti-cancer agents. Accordingly, the effect of two natural flavonoids (Chrysin and Daidzein) was investigated on the level of amphiregulin (AREG), chemokine ligand (CXCL1), and matrix metalloproteinase-9 (MMP-9) in 1, 2-dimethylhydrazine dihydrochloride (DMH) induced colorectal cancer. Rats were injected by DMH (40 mg/kg/week S.C.) for 16 weeks concomitantly with 2% dextran sodium sulfate (DSS) in drinking water for three cycles. Rats were orally treated with chrysin (125 and 250 mg/kg) and daidzein (5 and10 mg/kg) three times/week for the last 8 weeks. DMH + DSS group showed a significant (P < 0.05) increase in the levels of AREG (2386 ± 18 vs 1377 ± 10 pg/ml), CXCL1 (18 ± 0.9 vs 6 ± 0.83 <mu>g/ml), MMP-9 (1355 ± 88 vs 452 ± 7 pg/ml) compared to normal rats. These findings were associated with a potent antioxidant activity against cytochrome P450 2E1; (CYP2E1). Histopathological findings of the DMH + DSS group showed focal hyperplasia of the mucosa lining overlying crypts with moderate inflammation, dysplastic epithelial cells, and loss of goblet cells. Chrysin and daidzein treatment significantly (P < 0.05) restored the biochemical alterations and reverted histopathological findings near to the normal status. Moreover, chrysin and daidzein exerted anticancer activity against SW620 cells that were associated with decreased the protein expression of p-ERK/ERK and p-AKT/AKT. In conclusion, this study highlighted the potential anticancer role of chrysin and daidzein in the treatment of colon cancer.

NRF2 as a regulator of cell metabolism and inflammation in cancer

Nuclear factor erythroid 2-related factor 2 (NRF2) is a master transcriptional regulator of genes whose products defend our cells for toxic and oxidative insults. Although NRF2 activation may reduce cancer risk by suppressing oxidative stress and tumor-promoting inflammation, many cancers exhibit elevated NRF2 activity either due to mutations that disrupt the negative control of NRF2 activity or other factors. Importantly, NRF2 activation is associated with poor prognosis and NRF2 has turned out to be a key activator of cancer-supportive anabolic metabolism. In this review, we summarize the diverse roles played by NRF2 in cancer focusing on metabolic reprogramming and tumor-promoting inflammation.

Phytochemical compounds targeting on Nrf2 for chemoprevention in colorectal cancer

Colorectal cancer (CRC) has become one of the major factors of tumor-related morbidity and mortality in the world because of its poor prognosis and consequences of metastatic spread. Currently, chemoprevention has been considered as a way of preventing cancer who takes advantage of plant phytochemicals and synthetic compounds. Phytochemical compounds are receiving much considerable attention for their ability in chemoprevention due to low toxicity and cost. For strategies of chemoprevention, keeping the balance of internal and external environment in cells or tissues is important. Hence, it is particularly important to eliminate overmuch carcinogens and carcinogenic metabolites by phase 2 detoxifying enzymes and antioxidant enzymes such as glutathione S-transferase (GST), heme oxygenase-1(HO-1) and so on. Nuclear factor-erythroid 2-related factor 2 (Nrf2) plays a key role in regulating these enzymes via mediating antioxidant response elements (ARE). In this review, we collected recent studies of phytochemical compounds targeting on Nrf2 in CRC treatment. We summarized the mechanisms of these compounds in activating Nrf2, and their effects on chemotherapeutic agents.

Activation of NRF2 by topical apocarotenoid treatment mitigates radiation-induced dermatitis

Radiation therapy is a frontline treatment option for cancer patients; however, the effects of radiotherapy on non-tumor tissue (e.g. radiation-induced dermatitis) often worsen patient quality of life. Previous studies have implicated the importance of redox balance in preventing dermatitis, specifically in reference to modulation of the nuclear factor (erythroid-derived 2)-like 2 (NRF2) signaling pathway. Due to the cytoprotective functions of transcriptional target genes of NRF2, we investigated how modulation of NRF2 expression could affect DNA damage, oxidative stress, and cell viability in response to radiotherapy. Specifically, it was noted that NRF2 knockdown sensitized human skin keratinocytes to ionizing radiation; likewise, genetic ablation of NRF2 in vivo increased radiosensitivity of murine epidermis. Oppositely, pharmacological induction of NRF2 via the apocarotenoid bixin lowered markers of DNA damage and oxidative stress, while preserving viability in irradiated keratinocytes. Mechanistic studies indicated that topical pretreatment using bixin as an NRF2 activator antagonized initial DNA damage by raising cellular glutathione levels. Additionally, topical application of bixin prevented radiation-induced dermatitis, epidermal thickening, and oxidative stress in the skin of SKH1 mice. Overall, these data indicate that NRF2 is critical for mitigating the harmful skin toxicities associated with ionizing radiation, and that topical upregulation of NRF2 via bixin could prevent radiation-induced dermatitis.

Phytochemical and pharmacological review of Cinnamomum verum J. Presl-a versatile spice used in food and nutrition

Cinnamomum verum is the widely used spice for its medicinal and culinary uses since ages. It is native to Sri Lanka and southern India but also distributed in many Asian, Caribbean, Australian and African countries. It is widely used in food preparations and industrial products like candies, chewing gums, mouthwash and toothpaste. It is also used to treat asthma, bronchitis, diarrhea, headache, inflammation and cardiac disorders. Cinnamaldehyde, eugenol, caryophyllene, cinnamyl acetate and cinnamic acid are the major compounds found in its essential oil. These compounds exhibit a wide range of pharmacological activities including antioxidant, antimicrobial, anti-inflammatory, anticancer, antidiabetic, wound healing, anti-HIV, anti-anxiety and antidepressant, etc. This review highlights its comprehensive and up-to-date information on taxonomy, ethnomedicinal uses, phytochemical composition, pharmacological and toxicity activities. Structure-activity relationship, mechanism of action and some research gaps has also been provided. Owing to its immense medicinal importance, more well-designed in-vivo and clinical studies are required.

The role of natural products in revealing NRF2 function

Covering: up to 2020The transcription factor NRF2 is one of the body's major defense mechanisms, driving transcription of >300 antioxidant response element (ARE)-regulated genes that are involved in many critical cellular processes including redox regulation, proteostasis, xenobiotic detoxification, and primary metabolism. The transcription factor NRF2 and natural products have an intimately entwined history, as the discovery of NRF2 and much of its rich biology were revealed using natural products both intentionally and unintentionally. In addition, in the last decade a more sinister aspect of NRF2 biology has been revealed. NRF2 is normally present at very low cellular levels and only activated when needed, however, it has been recently revealed that chronic, high levels of NRF2 can lead to diseases such as diabetes and cancer, and may play a role in other diseases. Again, this "dark side" of NRF2 was revealed and studied largely using a natural product, the quassinoid, brusatol. In the present review, we provide an overview of NRF2 structure and function to orient the general reader, we will discuss the history of NRF2 and NRF2-activating compounds and the biology these have revealed, and we will delve into the dark side of NRF2 and contemporary issues related to the dark side biology and the role of natural products in dissecting this biology.

p62 promotes bladder cancer cell growth by activating KEAP1/NRF2-dependent antioxidative response

p62 is associated with 2 major cellular defense mechanisms against metabolic and oxidative stress, autophagy and the Kelch-like ECH-associated protein 1 (KEAP1)-nuclear factor-E2-related factor 2 (NRF2) system. Recent studies indicate that the p62-KEAP1-NRF2 pathway promotes tumorigenesis and tumor growth mediated by NRF2-dependent antioxidative response. However, whether p62 is involved in bladder cancer (BCa) development remains unknown. Here, we found that p62 is overexpressed in BCa tissue and several BCa cell lines. The knockdown of p62 inhibits BCa cell growth both in vitro and in vivo, with increased intracellular reactive oxygen species level. Mechanically, p62 activates NRF2 signaling by sequestrating KEAP1, which leads to the upregulation of antioxidant genes (Gclc, Gstm5, and Gpx2), thus protecting BCa cells from oxidative stress. Our findings indicate that p62 might be involved in the development of BCa and serve as a potential therapeutic target.

Metformin Activates the AMPK-mTOR Pathway by Modulating lncRNA TUG1 to Induce Autophagy and Inhibit Atherosclerosis

Background

Metformin has been shown to inhibit the proliferation and migration of vascular wall cells. However, the mechanism through which metformin acts on atherosclerosis (AS) via the long non-coding RNA taurine up-regulated gene 1 (lncRNA TUG1) is still unknown. Thus, this research investigated the effect of metformin and lncRNA TUG1 on AS.

Methods

First, qRT-PCR was used to detect the expression of lncRNA TUG1 in patients with coronary heart disease (CHD). Then, the correlation between metformin and TUG1 expression in vitro and their effects on proliferation, migration, and autophagy in vascular wall cells were examined. Furthermore, in vivo experiments were performed to verify the anti-AS effect of metformin and TUG1 to provide a new strategy for the prevention and treatment of AS.

Results

qRT-PCR results suggested that lncRNA TUG1 expression was robustly upregulated in patients with CHD. In vitro experiments indicated that after metformin administration, the expression of lncRNA TUG1 decreased in a time-dependent manner. Metformin and TUG1 knockdown via small interfering RNA both inhibited proliferation and migration while promoted autophagy via the AMPK/mTOR pathway in vascular wall cells. In vivo experiments with a rat AS model further demonstrated that metformin and sh-TUG1 could inhibit the progression of AS.

Conclusion

Taken together, our data demonstrate that metformin might function to prevent AS by activating the AMPK/mTOR pathway via lncRNA TUG1.

Current and emerging therapeutic targets of alzheimer's disease for the design of multi-target directed ligands

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease, and a major cause of death worldwide. The number of people suffering from this debilitating disorder is rising at an unprecedented rate, with a subsequent surge in healthcare costs. Only four drugs are clinically available for the treatment of AD symptoms, but they are not disease-modifying. Consequently, there is an urgent need for a cure. Although the cause of this debilitating condition remains poorly understood, it is believed that several factors may be involved in combination - including, health and lifestyle, environmental, and genetic factors. In recent years, a number of hallmarks of the disease have also been discovered, and it is believed that these factors may play an important role in the development of AD. Amyloid aggregation is one such factor which has been highly investigated, in addition to cholinesterase enzymes and tau aggregation. In the last decade, multi-target drugs have been increasingly investigated for their application to AD treatment. By combining two or more pharmacophores in a single compound, it is possible to synthesise a drug which can target several factors that are involved in AD development. This is a particularly attractive approach as it would avoid the use of combination therapies. As a result, it could reduce the burden on carers and families, and decrease healthcare and social care costs. Many active pharmacophores have been employed for the development of hybrid drugs, due to their abilities to inhibit the factors currently widely recognised to be involved in AD. These compounds have demonstrated promising results; however, research is still required to optimise the pharmacological profiles of the drugs, in addition to their potencies. Meanwhile, extensive research is continuously being performed into other potential targets for the treatment of AD. Based on the results obtained thus far, it is likely that multi-target compounds will continue to be increasingly studied in the future as potential treatments for AD.

Development of resveratrol-conjugated gold nanoparticles: interrelationship of increased resveratrol corona on anti-tumor efficacy against breast, pancreatic and prostate cancers

Background: As part of our continuing quest to enhance the efficacy of bioactive phytochemicals in cancer therapy, we report an innovative green nanotechnology approach toward the use of resveratrol for the production of biocompatible resveratrol-conjugated gold nanoparticles (Res-AuNPs). Our overarching aim is to exploit the inherent pro-apoptotic properties of gold nanoparticles (AuNPs) through synergistic anti-tumor characteristics of resveratrol, with the aim of developing a new class of green nanotechnology-based phytochemical-embedded AuNPs for applications in oncology.

Method: Resveratrol was used to reduce Au³⁺ to Au⁰ for the synthesis of Res-AuNPs at room temperature and gum arabic (GA) was used to further encapsulate the nanoparticulate surface to increase the overall stability of the AuNPs. This comprehensive study involves the synthesis, full characterization and in vitro stability of Res-AuNPs in various biological media for their ultimate applications as anti-cancer agents against human breast (MDAMB-231), pancreatic (PANC-1) and prostate (PC-3) cancers.

Results: This strategy to systematically increase the corona of resveratrol on AuNPs, in order to gain insights into the interrelationship of the phytochemical corona on the overall anti-tumor activities of Res-AuNPs, proved successful. The increased resveratrol corona on Res-AuNPs showed superior anti-cancer effects, attributed to an optimal cellular uptake after 24-hour incubation, while GA provided a protein matrix support for enhanced trans-resveratrol loading onto the surface of the AuNPs.

Conclusion: The approach described in this study harnesses the benefits of nutraceuticals and nanoparticles toward the development of Res-AuNPs. We provide compelling evidence that the increased corona of resveratrol on AuNPs enhances the bioavailability of resveratrol so that therapeutically active species can be optimally available in vivo for applications in cancer therapy.

Anti-cancer effects of cinnamon: Insights into its apoptosis effects

Cancer is known as a leading cause of death worldwide. In the last two decades, the incidence of cancer has been dramatically increased mostly due to lifestyle changes. The importance of this issue has attracted further attention to discover novel therapies to prevent and treat cancers. According to previous studies, drugs used to treat cancer have shown significant limitations. Therefore, the role of herbal medicines alone or in combination with chemotherapy drugs has been extensively studied in cancer treatment. Cinnamon is a natural component showing a wide range of pharmacological functions including anti-oxidant, anti-microbial and anti-cancer activities. Impaired apoptosis plays critical roles in the initiation and progression of cancer. Increasing evidence indicates that cinnamon, as a therapeutic agent, has anti-cancer effects via affecting numerous apoptosis-related pathways in cancer cells. Here, we highlighted anticancer properties of cinnamon, particularly through targeting apoptosis-related mechanisms.

Protective effects of novel derivatives of vitamin D3 and lumisterol against UVB-induced damage in human keratinocytes involve activation of Nrf2 and p53 defense mechanisms

We tested whether novel CYP11A1-derived vitamin D₃- and lumisterol-hydroxyderivatives, including 1,25(OH)₂D₃, 20(OH)D₃, 1,20(OH)₂D₃, 20,23(OH)₂D₃, 1,20,23(OH)₃D₃, lumisterol, 20(OH)L₃, 22(OH)L₃, 20,22(OH)₂L₃, and 24(OH)L₃, can protect against UVB-induced damage in human epidermal keratinocytes. Cells were treated with above compounds for 24 h, then subjected to UVB irradiation at UVB doses of 25, 50, 75, or 200 mJ/cm², and then examined for oxidant formation, proliferation, DNA damage, and the expression of genes at the mRNA and protein levels. Oxidant formation and proliferation were determined by the DCFA-DA and MTS assays, respectively. DNA damage was assessed using the comet assay. Expression of antioxidative genes was evaluated by real-time RT-PCR analysis. Nuclear expression of CPD, phospho-p53, and Nrf2 as well as its target proteins including HO-1, CAT, and MnSOD, were assayed by immunofluorescence and western blotting. Treatment of cells with the above compounds at concentrations of 1 or 100 nM showed a dose-dependent reduction in oxidant formation. At 100 nM they inhibited the proliferation of cultured keratinocytes. When keratinocytes were irradiated with 50–200 mJ/cm² of UVB they also protected against DNA damage, and/or induced DNA repair by enhancing the repair of 6-4PP and attenuating CPD levels and the tail moment of comets. Treatment with test compounds increased expression of Nrf2-target genes involved in the antioxidant response including GR, HO-1, CAT, SOD1, and SOD2, with increased protein expression for HO-1, CAT, and MnSOD. The treatment also stimulated the phosphorylation of p53 at Ser-15, increased its concentration in the nucleus and enhanced Nrf2 translocation into the nucleus. In conclusion, pretreatment of keratinocytes with 1,25(OH)₂D₃ or CYP11A1-derived vitamin D₃- or lumisterol hydroxy-derivatives, protected them against UVB-induced damage via activation of the Nrf2-dependent antioxidant response and p53-phosphorylation, as well as by the induction of the DNA repair system. Thus, the new vitamin D₃ and lumisterol hydroxy-derivatives represent promising anti-photodamaging agents.

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Vitamin D₃ and lumisterol derivatives stimulate antioxidative responses in skin.

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Vitamin D₃ and lumisterol derivatives protect against UVB-induced DNA damage.

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Vitamin D₃ and lumisterol derivatives target p53 and Nrf2-antioxidant pathways.

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Vitamin D₃ and lumisterol derivatives promise to be skin photoprotectors

Mkp-1 is required for chemopreventive activity of butylated hydroxyanisole and resveratrol against colitis-associated colon tumorigenesis

Many dietary compounds show promising protective activity against colon cancer by activating nuclear factor-erythroid 2 related factor 2 (Nrf2). Recently, we reported that mitogen-activated protein kinase phosphatase 1 (Mkp-1) exhibits crosstalk with the Nrf2 signaling pathway, protecting against intestinal inflammation. Here, we present evidence that Mkp-1 is required for the chemopreventive action of the Nrf2 activators butylated hydroxyanisole (BHA) and resveratrol (RSV). In an azoxymethane/dextran sulfate sodium model of colitis-associated tumorigenesis, Mkp-1^-/- mice exhibited a phenotype similar to Nrf2^-/- mice with significantly more tumors than WT mice. Tumors from Mkp-1^-/- mice exhibited higher levels of macrophage infiltration than those from WT mice. This was accompanied by increased expression of nitrotyrosine and p53BP1, markers of oxidative stress and DNA damage, respectively. Moreover, dietary suppression of tumorigenesis using BHA (0.5%) or RSV (300 ppm) supplementation was achieved in WT but not in Mkp-1^-/- mice. In adenomas from WT mice, the expression of Mkp-1 was markedly lower than in adjacent normal tissue, concomitant with the down-regulation of Nrf2 and its target genes. Our data revealed that Mkp-1 is required in the protective role of Nrf2 signaling against colitis-associated tumorigenesis.

Chemoprevention of Colorectal Cancer by Dietary Compounds

Colorectal cancer is one of the leading causes of death, and the third most diagnosed type of cancer, worldwide. It is most common amongst men and women over 50 years old. Risk factors include smoking, alcohol, diet, physical inactivity, genetics, alterations in gut microbiota, and associated pathologies (diabetes, obesity, chronic inflammatory bowel diseases). This review will discuss, in detail, the chemopreventive properties of some dietary compounds (phenolic compounds, carotenoids, iridoids, nitrogen compounds, organosulfur compounds, phytosterols, essential oil compounds, polyunsaturated fatty acids and dietary fiber) against colorectal cancer. We present recent data, focusing on in vitro, laboratory animals and clinical trials with the previously mentioned compounds. The chemopreventive properties of the dietary compounds involve multiple molecular and biochemical mechanisms of action, such as inhibition of cell growth, inhibition of tumor initiation, inhibition of adhesion, migration and angiogenesis, apoptosis, interaction with gut microbiota, regulation of cellular signal transduction pathways and xenobiotic metabolizing enzymes, etc. Moreover, this review will also focus on the natural dietary compounds' bioavailability, their synergistic protective effect, as well as the association with conventional therapy. Dietary natural compounds play a major role in colorectal chemoprevention and continuous research in this field is needed.

Encapsulation of cinnamon essential oil in whey protein enhances the protective effect against single or combined sub-chronic toxicity of fumonisin B1 and/or aflatoxin B1 in rats

Fumonisin B₁ (FB₁) and aflatoxin B₁ (AFB₁) are fungal metabolites that frequently co-occur in foodstuffs and are responsible for mycotoxicosis and several primary cancers. Cinnamon essential oil (CEO) has a spacious range of benefit effects but also has some limitations owing to its strong taste or its interaction with some drugs. This study aimed to use the cinnamon oil emulsion droplets (COED) for the protection against oxidative stress, cytotoxicity, and reproductive toxicity in male Sprague-Dawley rats sub-chronically exposed to FB₁ and/or AFB₁. The composition of CEO was identified using GC-MS then was encapsulated using whey protein as wall material. Male rats were divided into eight groups and treated orally for 8 weeks as follows: control group, AFB₁-trreated group (80 μg/kg b.w), FB₁-treated group (100 mg/kg b.w), FB₁ plus AFB₁-treated group, and the groups treated with COED plus FB₁ and/or AFB₁. Blood and samples of the kidney, liver, and testis were collected for different analysis and histopathological examination. The GC-MS analysis revealed that cinnamaldehyde, α-copaene, trans-cinnamaldehyde, caryophyllene, and delta-cadinene were the main compounds in COE. The average size of COED was 235 ± 1.4 nm and the zeta potential was - 6.24 ± 0.56. Treatment with FB₁ and/or AFB₁ induced significant disturbances in the serum biochemical analysis, oxidative stress parameters, DNA fragmentation, gene expression, and testosterone and severe pathological changes in the tested organs. Moreover, treatment with both mycotoxins induced synergistic toxic effects. COED did not induce toxic effects and could normalize the majority of the tested parameters and improve the histological picture in rats treated with FB₁ and/or AFB₁. It could be concluded that COED induce potential protective effects against the single or combined exposure to FB₁ and AFB₁.