Natural Forms of Vitamin E as Effective Agents for Cancer Prevention and Therapy

Characterization, phytochemical profiling, antioxidant, and cytotoxicity of underutilized medicinal plants and composite flour

In this investigation, three medicinal plant powders and a composite flour developed from them were analyzed. FESEM/EDS illustrated irregularly shaped particles in the plant powders except for Withania, which had round to oval shape particles. XRD analysis displayed a semi-crystalline nature of powders, except for Asparagus, which showed amorphous behavior. Both methanol and ethanol plant extracts exhibited significantly higher antioxidants, total phenols, and cell viability. Amongst, optimized composite flour (OCF) methanolic extract demonstrated the highest total phenolic content (69.2 ± 0.11 μg GAE/ml), potent cell viability against A549 cells (3.35 ± 0.15% at 50 μg/ml), and strong free-radical scavenging activity (48.89 ± 0.67 at 200 μg/ml). GCMS and FTIR analyses of the methanolic extracts demonstrated the presence of essential phytoconstituents and functional groups. In silico studies of the phytocomponents, ethyl isoallocholate, 3-Deoxy-d-mannoic lactone, and 4,5-Diamino-2-hydroxypyrimidine suggested good binding affinity against BAX, P53, and EGFR proteins with no toxicity and a good drug score.

Different Roles of Tocopherols and Tocotrienols in Chemoprevention and Treatment of Prostate Cancer

The vitamin E family contains α-tocopherol (αT), βT, γT, and δT and α-tocotrienol (TE), βTE, γTE, and δTE. Research has revealed distinct roles of these vitamin E forms in prostate cancer (PCa). The ATBC trial showed that αT at a modest dose significantly decreased PCa mortality among heavy smokers. However, other randomized controlled trials including the Selenium and Vitamin E Cancer Prevention Trial (SELECT) indicate that supplementation of high-dose αT (≥400 IU) does not prevent PCa among nonsmokers. Preclinical cell and animal studies also do not support chemopreventive roles of high-dose αT and offer explanations for increased incidence of early-stage PCa reported in the SELECT. In contrast, accumulating animal studies have demonstrated that γT, δT, γTE, and δTE appear to be effective for preventing early-stage PCa from progression to adenocarcinoma in various PCa models. Existing evidence also support therapeutic roles of γTE and its related combinations against advanced PCa. Mechanistic and cell-based studies show that different forms of vitamin E display varied efficacy, that is, δTE ≥ γTE > δT ≥ γT >> αT, in inhibiting cancer hallmarks and enabling characteristics, including uncontrolled cell proliferation, angiogenesis, and inflammation possibly via blocking 5-lipoxygenase, nuclear factor κB, hypoxia-inducible factor-1α, modulating sphingolipids, and targeting PCa stem cells. Overall, existing evidence suggests that modest αT supplement may be beneficial to smokers and γT, δT, γTE, and δTE are promising agents for PCa prevention for modest-risk to relatively high-risk population. Despite encouraging preclinical evidence, clinical research testing γT, δT, γTE, and δTE for PCa prevention is sparse and should be considered.

Emissions from plastic incineration induce inflammation, oxidative stress, and impaired bioenergetics in primary human respiratory epithelial cells

Inhalation exposure to plastic incineration emissions (PIEs) is a problem of increasing human relevance, as plastic production and waste creation have drastically increased since mainstream integration during the 20th century. We investigated the effects of PIEs on human nasal epithelial cells (HNECs) to understand if such exposures cause damage and dysfunction to respiratory epithelia. Primary HNECs from male and female donors were cultured at air-liquid interface (ALI), and 16HBE cells were cultured on coverslips. Smoke condensates were generated from incineration of plastic at flaming (640°C) and smoldering (500°C) temperatures, and cells were subsequently exposed to these materials at 5-50 μg/cm2 concentrations. HNECs were assessed for mitochondrial dysfunction and 16HBE cells for glutathione oxidation in real-time analyses. HNEC culture supernatants and total RNA were collected at 4-h postexposure for cytokine and gene expression analysis, and results show that PIEs can acutely induce inflammation, oxidative stress, and mitochondrial dysfunction in HNECs, and that incineration temperature modifies biological responses. Specifically, condensates from flaming and smoldering PIEs significantly increased HNEC secretion of cytokines IL-8, IL-1β, and IL-13, as well as expression of xenobiotic metabolism pathways and genes such as CYP1A1 and CYP1B1 at 5 and 20 μg/cm2 concentrations. Only 50 μg/cm2 flaming PIEs significantly increased glutathione oxidation in 16HBEs, and decreased respiration and ATP production in HNEC mitochondria. Impact Statement: Our data reveal the impact of incineration temperatures on biological outcomes associated with PIE exposures, emphasizing the importance of temperature as a factor when evaluating respiratory disease associated with PIEs exposure.

LINC01535 promotes hepatocellular carcinoma proliferation and metastasis by regulating the miR-214-3p/VASP axis

Background: Emerging evidence has indicated that long noncoding RNAs (lncRNAs) are associated with the development and progression of several carcinomas, including hepatocellular carcinoma (HCC). However, the role of LINC01535 in HCC is still unknown. Materials and methods: In this study, RNA-seq, CCK-8, colony formation, wound healing, Transwell and tumor xenograft assays were used to explore the function of LINC01535 in the proliferation and metastasis of HCC in vitro and in vivo. Fluorescence in situ hybridization (FISH) assay, bioinformatics analysis, dual-luciferase assay, quantitative real-time polymerase chain reaction (qRT-PCR), and western blot analysis were used to reveal the interactions of LINC01535, miR-214-3p and VASP. Results: LINC01535 was overexpressed in HCC tissues and HCC cell lines. Gain- and loss-of-function studies revealed that LINC01535 could promote HCC cell proliferation, migration and invasion both in vitro and in vivo. In addition, upregulation of LINC01535 significantly decreased the expression of microRNA-214-3p (miR-214-3p), which was found closely associated with suppressing tumor progression. Moreover, VASP was identified as a direct downstream target gene of miR-214-3p. LINC01535 positively regulated VASP expression by sponging miR-214-3p, and VASP overexpression activated the PI3K/AKT signaling pathway and stimulated epithelial-to-mesenchymal transition (EMT) in HCC. Conclusions: Our study first found that LINC01535 promoted HCC progression by regulating its downstream target, the miR-214-3p/VASP axis, via the PI3K/AKT signaling pathway. The function and novel regulatory mechanism of LINC01535 may provide a valuable target for the diagnosis and treatment of HCC patients.

Chemopreventive effects of α-tocopherol and its long-chain metabolites α-13'-hydroxy- and α-13'-carboxychromanol in LT97 colon adenoma cells

Anticancer effects of vitamin E (tocopherols) have been studied extensively. While in vitro and animal studies showed promising results regarding anticancer effects of tocopherols, human intervention studies failed to reproduce these results. In vivo, α-tocopherol (α-TOH) is metabolized to the long-chain metabolites (LCM) 13'-hydroxychromanol (α-13'-OH) and 13'-carboxychromanol (α-13'-COOH), which likely reach the large intestine. The LCM showed antiproliferative effects in different colon cancer cell lines, but the exact mechanism of action remains unclear. To further clarify the chemopreventive action of the LCM, premalignant LT97 colon adenoma cells were treated with α-TOH, α-13'-OH and α-13'-COOH to study their impact on growth, apoptosis, antigenotoxicity, and ROS-scavenging capacity as well as expression of selected genes involved in detoxification and the cell cycle. Growth inhibitory potential was observed for α-13'-OH (IC50: 37.4 μM) and α-13'-COOH (IC50: 5.8 μM) but not for α-TOH in the tested concentrations. Levels of caspase-3 activity and expression of genes regulating the cell cycle and detoxification remained unchanged. However, α-TOH, α-13'-OH and α-13'-COOH exhibited antigenotoxic and partly ROS-scavenging capacity. The results indicate that the LCM exert chemopreventive effects via ROS-scavenging capacity, the protection against DNA damage and the induction of cell death via caspase-independent mechanisms in premalignant colon cells.

Delta-tocotrienol disrupts PD-L1 glycosylation and reverses PD-L1-mediated immune suppression

PD-L1-mediated immune escape plays an important role in cancer development and progression. Targeting PD-L1 is consider to be an attractive approach for cancer treatment. PD-L1 is a heavily N-linked glycosylated protein, and the glycosylation of PD-L1 is essential for its ability to interact with its receptor PD-1 to mediate immune suppression. In the present study, we demonstrated for the first time that delta-tocotrienol (δ-T3) not any of the other forms of vitamin E was able to disrupt PD-L1 glycosylation mechanistically associated with the suppression of TCF4-STT3a/STT3b axis. The inhibition of PD-L1 glycosylation by δ-T3 resulted in the decrease of PD-L1 expression and its exosomal secretion, leading to the reduction of PD-L1 and PD-1 interaction, and reversing PD-L1-mediated immune suppression, which in turn contributed to the inhibitory effect on tumor growth. The findings of the present study provide a novel mechanistic interpretation for the superior anticancer activity of δ-T3 among 8 isomers of the vitamin E.

Effect of Regular Consumption of a Miraculin-Based Food Supplement on Taste Perception and Nutritional Status in Malnourished Cancer Patients: A Triple-Blind, Randomized, Placebo-Controlled Clinical Trial-CLINMIR Pilot Protocol

Taste disorders are common among cancer patients undergoing chemotherapy, with a prevalence ranging from 20% to 86%, persisting throughout treatment. This condition leads to reduced food consumption, increasing the risk of malnutrition. Malnutrition is associated not only with worse treatment efficacy and poor disease prognosis but also with reduced functional status and quality of life. The fruit of Synsepalum dulcificum (Daniell), commonly known as miracle berry or miracle fruit, contains miraculin, a taste-modifying protein with profound effects on taste perception. The CLINMIR Protocol is a triple-blind, randomized, placebo-controlled clinical trial designed to evaluate the regular consumption of a food supplement containing a miraculin-based novel food, dried miracle berry (DMB), on the taste perception (measured through electrogustometry) and nutritional status (evaluated through the GLIM Criteria) of malnourished cancer patients under active antineoplastic treatment. To this end, a pilot study was designed with 30 randomized patients divided into three study arms (150 mg DMB + 150 mg freeze-dried strawberries, 300 mg DMB, or placebo) for three months. Throughout the five main visits, an exhaustive assessment of different parameters susceptible to improvement through regular consumption of the miraculin-based food supplement will be conducted, including electrical and chemical taste perception, smell perception, nutritional and morphofunctional assessment, diet, quality of life, the fatty acid profile of erythrocytes, levels of inflammatory and cancer-associated cytokines, oxidative stress, antioxidant defense system, plasma metabolomics, and saliva and stool microbiota. The primary anticipated result is that malnourished cancer patients with taste distortion who consume the miraculin-based food supplement will report an improvement in food taste perception. This improvement translates into increased food intake, thereby ameliorating their nutritional status and mitigating associated risks. Additionally, the study aims to pinpoint the optimal dosage that provides maximal benefits. The protocol adheres to the SPIRIT 2013 Statement, which provides evidence-based recommendations and is widely endorsed as an international standard for trial protocols. The clinical trial protocol has been registered at the platform for Clinical Trials (NCT05486260).

Vitamins as regulators of calcium-containing kidney stones - new perspectives on the role of the gut microbiome

Calcium-based kidney stone disease is a highly prevalent and morbid condition, with an often complicated and multifactorial aetiology. An abundance of research on the role of specific vitamins (B6, C and D) in stone formation exists, but no consensus has been reached on how these vitamins influence stone disease. As a consequence of emerging research on the role of the gut microbiota in urolithiasis, previous notions on the contribution of these vitamins to urolithiasis are being reconsidered in the field, and investigation into previously overlooked vitamins (A, E and K) was expanded. Understanding how the microbiota influences host vitamin regulation could help to determine the role of vitamins in stone disease.

The First Physiologically Based Pharmacokinetic (PBPK) Model for an Oral Vaccine Using Alpha-Tocopherol as an Adjuvant

Oral vaccines represent many advantages compared to standard vaccines. They hold a simple method of administration and manufacturing process. In addition to these, the way they can induce immune responses makes these a promising technology for the pharmaceutical industry and represents a new hope to society. Physiologically based pharmacokinetics (PBPK) has been used in support of drug development to predict the pharmacokinetics of the compound, considering the patient's physiology. Despite PBPK studies now being widely used, there are very few models in the literature that support vaccine development. Therefore, the goal of this article was to determine how PBPK could support vaccine development. The first PBPK model for an oral vaccine using alpha-tocopherol as a vaccine adjuvant was built. LogP is the parameter that influences the delivery of alpha-tocopherol into the tissues more. Having a high LogP means it accumulates in adipose tissue and is slowly metabolized. The ideal formulation to include alpha-tocopherol in an oral vaccine would incorporate nanoparticles in a capsule, and the dosage of the compound would be 150 mg in a volume of 200 mL. This article aims to determine if alpha-tocopherol, as a well-known adjuvant for intramuscular injection vaccines, could be used as an adjuvant to oral vaccines. This model was built considering the conditions and requirements needed for designing an oral vaccine. This implies making sure the antigen and adjuvants reach the main target by overcoming the challenges of the gastrointestinal tract. The main parameters that would need to be included in a formulation using alpha-tocopherol as an adjuvant were determined.

Vitamin E and Multiple Health Outcomes: An Umbrella Review of Meta-Analyses

The relationship between vitamin E intake or circulating α-tocopherol and various health outcomes is still debatable and uncertain. We conducted an umbrella review to identify the relationships between vitamin E intake or circulating tocopherol and health outcomes by merging and recalculating earlier meta-analyses. The connections that were found to be statistically significant were then classified into different evidence levels based on p values, between-study heterogeneity, prediction intervals, and small study effects. We finally included 32 eligible meta-analyses with four vitamin E sources and 64 unique health outcomes. Only the association between circulating α-tocopherol and wheeze or asthma in children was substantiated by consistent evidence. Suggestive evidence was suggested for seven results on endothelial function (supplemental vitamin E): serum C-reactive protein (CRP) concentrations (supplemental vitamin E), cervical cancer (dietary vitamin E), esophageal cancer (dietary vitamin E), cervical intraepithelial neoplasia (CIN, dietary vitamin E), pancreatic cancer (total vitamin E intake), and colorectal cancer (circulating α-tocopherol levels); all of these showed a protective effect consistent with the vitamin E source. In conclusion, our work has indicated that vitamin E is protective for several particular health outcomes. Further prospective studies are required when other factors that may contribute to bias are considered.

Vitamin E in the management of pancreatic cancer: A scoping review

Pancreatic cancer is the leading cause of cancer mortality worldwide. Research investigating effective management strategies for pancreatic cancer is ongoing. Vitamin E, consisting of both tocopherol and tocotrienol, has demonstrated debatable effects on pancreatic cancer cells. Therefore, this scoping review aims to summarize the effects of vitamin E on pancreatic cancer. In October 2022, a literature search was conducted using PubMed and Scopus since their inception. Original studies on the effects of vitamin E on pancreatic cancer, including cell cultures, animal models and human clinical trials, were considered for this review. The literature search found 75 articles on this topic, but only 24 articles met the inclusion criteria. The available evidence showed that vitamin E modulated proliferation, cell death, angiogenesis, metastasis and inflammation in pancreatic cancer cells. However, the safety and bioavailability concerns remain to be answered with more extensive preclinical and clinical studies. More in-depth analysis is necessary to investigate further the role of vitamin E in the management of pancreatic cancers.

α-Tocopherol-13'-Carboxychromanol Induces Cell Cycle Arrest and Cell Death by Inhibiting the SREBP1-SCD1 Axis and Causing Imbalance in Lipid Desaturation

α-Tocopherol-13'-carboxychromanol (α-T-13'-COOH) is an endogenously formed bioactive α-tocopherol metabolite that limits inflammation and has been proposed to exert lipid metabolism-regulatory, pro-apoptotic, and anti-tumoral properties at micromolar concentrations. The mechanisms underlying these cell stress-associated responses are, however, poorly understood. Here, we show that the induction of G₀/G₁ cell cycle arrest and apoptosis in macrophages triggered by α-T-13'-COOH is associated with the suppressed proteolytic activation of the lipid anabolic transcription factor sterol regulatory element-binding protein (SREBP)1 and with decreased cellular levels of stearoyl-CoA desaturase (SCD)1. In turn, the fatty acid composition of neutral lipids and phospholipids shifts from monounsaturated to saturated fatty acids, and the concentration of the stress-preventive, pro-survival lipokine 1,2-dioleoyl-sn-glycero-3-phospho-(1'-myo-inositol) [PI(18:1/18:1)] decreases. The selective inhibition of SCD1 mimics the pro-apoptotic and anti-proliferative activity of α-T-13'-COOH, and the provision of the SCD1 product oleic acid (C18:1) prevents α-T-13'-COOH-induced apoptosis. We conclude that micromolar concentrations of α-T-13'-COOH trigger cell death and likely also cell cycle arrest by suppressing the SREBP1-SCD1 axis and depleting cells of monounsaturated fatty acids and PI(18:1/18:1).

The Biochemistry and Effectiveness of Antioxidants in Food, Fruits, and Marine Algae

It is more effective to maintain good health than to regain it after losing it. This work focuses on the biochemical defense mechanisms against free radicals and their role in building and maintaining antioxidant shields, aiming to show how to balance, as much as possible, the situations in which we are exposed to free radicals. To achieve this aim, foods, fruits, and marine algae with a high antioxidant content should constitute the basis of nutritional elements, since natural products are known to have significantly greater assimilation efficiency. This review also gives the perspective in which the use of antioxidants can extend the life of food products, by protecting them from damage caused by oxidation as well as their use as food additives.

Role of Antioxidant Vitamins and Other Micronutrients on Regulations of Specific Genes and Signaling Pathways in the Prevention and Treatment of Cancer

Cancer is an escalating global issue, with 19.3 million new cases and 9.9 million deaths in 2020. Therefore, effective approaches to prevent cancer are urgently required. Diet plays a significant role in determining cancer risk. Nutrients and food bioactives influence specific signaling pathways in the body. Recently, there have been significant advances in cancer prevention research through nutrigenomics or with the effects of dietary components on the genome. Google Scholar, PubMed, and Scopus databases were used to search for peer-reviewed articles between 2017 and 2023. Criteria used were vitamins, minerals, tumors, cancer, genes, inflammation, signaling pathways, and nutrigenomics. Among the total of 1857 articles available, the highest relevant 90 articles that specifically discussed signaling pathways and genes on cancer cell lines and human cancer patients were selected and reviewed. Food sources are rich in antioxidant micronutrients, which are effective in activating or regulating signaling pathways involved in pathogenesis and cancer therapy by activating enzymes such as mitogen-activated protein kinase (MAPK), protein kinase C (PKC), and phosphatidylinositol 3-kinase (PI3K). The micronutrients are involved in the regulation of β-catenin (WNT/β-catenin) including mutations in Kras and epidermal growth factor receptor (EGFR) alongside inhibition of the NF-kB pathway. The most common mechanism of cancer prevention by these micronutrients is their antioxidative, anti-inflammation, and anti-apoptosis effects. This review discusses how nutrigenomics is essential and beneficial for developing cancer prevention and treatment approaches.

Potential Role of Natural Antioxidant Products in Oncological Diseases

Nutrition has a significant effect and a crucial role in disease prevention. Low consumption of fruit and vegetables and a sedentary lifestyle are closely related with the onset and development of many types of cancer. Recently, nutraceuticals have gained much attention in cancer research due to their pleiotropic effects and relatively non-toxic behavior. In fact, although in the past there have been conflicting results on the role of some antioxidant compounds as allies against cancer, numerous recent clinical studies highlight the efficacy of dietary phytochemicals in the prevention and treatment of cancer. However, further investigation is necessary to gain a deeper understanding of the potential anticancer capacities of dietary phytochemicals as well as the mechanisms of their action. Therefore, this review examined the current literature on the key properties of the bioactive components present in the diet, such as carotenoids, polyphenols, and antioxidant compounds, as well as their use in cancer therapy. The review focused on potential chemopreventive properties, evaluating their synergistic effects with anticancer drugs and, consequently, the side effects associated with current cancer treatments.

Protective Effect of alpha-Tocopherol against Ochratoxin A in Kidney Cell Line HK-2

Food safety is a top priority for the protection of infants and young children. Ochratoxin A (OTA) is an emerging concern due to its high toxicity and occurrence in a wide range of agricultural crops and their derived food products including those foods and snacks destined for infants and young children. OTA is considered as a possible human carcinogen and its main target organ is the kidney. The objective of this study was to investigate the protective effect of α-tocopherol against oxidative stress induced by OTA using human proximal tubule epithelial cells (HK-2). OTA showed dose-dependent increase in cytotoxicity (IC₅₀ = 161 nM, p<0.05) at 48 h, while treatment up to 2 mM α-tocopherol did not change cell viability. Levels of the reduced form of glutathione (GSH) were decreased with α-tocopherol treatment, although the ratio of the oxidative form (GSSG) to GSH remained the same. Among several genes associated with oxidative stress, expression of superoxide dismutase 1 (SOD1), catalase (CAT), glutathione reductase (GSR), and kidney injury molecule-1 (KIM-1) were significantly up-regulated by OTA treatment. CAT and GSR showed decreased expression at 0.5 - 2 mM α-tocopherol and OTA at IC₅₀ value, KIM-1 was decreased at 0.5 mM α-tocopherol and OTA at IC₅₀ value, and nuclear factor erythroid 2-related factor 2 (Nrf2) was decreased at 0.5 - 1 mM α-tocopherol and OTA at IC₅₀ value. In addition, the levels of malondialdehyde (MDA) were increased significantly by OTA while significantly decreased by α-tocopherol. The results show that α-tocopherol may alleviate potential OTA-induced renal damage and oxidative stress through reducing cytotoxicity and enhancing the antioxidant defense systems.

A Comprehensive Review of Health-Benefiting Components in Rapeseed Oil

Rapeseed oil is the third most consumed culinary oil in the world. It is well-known for its high content of unsaturated fatty acids, especially polyunsaturated fatty acids, which make it of great nutritional value. There is increasing evidence that a diet rich in unsaturated fatty acids offers health benefits. Although the consumption of rapeseed oil cuts across many areas around the world, the nutritional elements of rapeseed oil and the exact efficacy of the nutrients remain unclear. In this review, we systematically summarized the latest studies on functional rapeseed components to ascertain which component of canola oil contributes to its function. Apart from unsaturated fatty acids, there are nine functional components in rapeseed oil that contribute to its anti-microbial, anti-inflammatory, anti-obesity, anti-diabetic, anti-cancer, neuroprotective, and cardioprotective, among others. These nine functional components are vitamin E, flavonoids, squalene, carotenoids, glucoraphanin, indole-3-Carbinol, sterols, phospholipids, and ferulic acid, which themselves or their derivatives have health-benefiting properties. This review sheds light on the health-benefiting effects of rapeseed oil in the hope of further development of functional foods from rapeseed.

Antioxidant Green Factories: Toward Sustainable Production of Vitamin E in Plant In Vitro Cultures

Vitamin E is a dietary supplement synthesized only by photosynthetic organisms and, hence, is an essential vitamin for human well-being. Because of the ever-increasing demand for natural vitamin E and limitations in existing synthesis modes, attempts to improve its yield using plant in vitro cultures have gained traction in recent years. With inflating industrial production costs, integrative approaches to conventional bioprocess optimization is the need of the hour for multifold vitamin E productivity enhancement. In this review, we briefly discuss the structure, isomers, and important metabolic routes of biosynthesis for vitamin E in plants. We then emphasize its vital role in human health and its industrial applications and highlight the market demand and supply. We illustrate the advantages of in vitro plant cell/tissue culture cultivation as an alternative to current commercial production platforms for natural vitamin E. We touch upon the conventional vitamin E metabolic pathway engineering strategies, such as single/multigene overexpression and chloroplast engineering. We highlight the recent progress in plant systems biology to rationally identify metabolic bottlenecks and knockout targets in the vitamin E biosynthetic pathway. We then discuss bioprocess optimization strategies for sustainable vitamin E production, including media/process optimization, precursor/elicitor addition, and scale-up to bioreactors. We culminate the review with a short discussion on kinetic modeling to predict vitamin E production in plant cell cultures and suggestions on sustainable green extraction methods of vitamin E for reduced environmental impact. This review will be of interest to a wider research fraternity, including those from industry and academia working in the field of plant cell biology, plant biotechnology, and bioprocess engineering for phytochemical enhancement.

Effect of vitamins C and E on cancer survival; a systematic review

PURPOSE

Association between vitamins C (VC)/ E (VE) and cancer survival is inconsistent. This systematic review is aimed to summarize trials for effects of VC/VE on cancer survival.

METHODS

Relevant English trials were retrieved from PubMed, Cochrane Library, Embase, Web of Science, Scopus databases, and Clinicaltrials.gov through 21/June/2022. Inclusion criteria were all trials which assessed sole/combinations intake of VC/VE on survival rate, mortality, or remission of any cancer. Exclusion criteria were observational and animal studies.

RESULTS

We reached 30 trials conducted on 38,936 patients with various cancers. Due to severe methodological heterogeneity, meta-analysis was impossible. High dose VC + chemotherapy or radiation was safe with an overall survival (OS) 182 days - 21.5 months. Sole oral or intravenous high dose VC was safe with non-significant change in OS (2.9-8.2 months). VE plus chemotherapy was safe, resulted in stabling diseases for 5 years in 70- 86.7% of patients and OS 109 months. It was found 60% and 16% non-significant reductions in adjusted hazard ratio (HR) deaths or recurrence by 200 mg/d tocotrienol + tamoxifen in breast cancer, respectively. Sole intake of 200-3200 mg/d tocotrienol before resectable pancreatic cancer was safe and significantly increased cancer cells' apoptosis. Combination VC and VE was non-significantly reduced 7% in rate of neoplastic gastric polyp.

CONCLUSION

Although our study is supported improvement of survival and progression rates of cancers by VC/VE, more high quality trials with large sample sizes are required to confirm.

PROSPERO REGISTRATION NUMBER

CRD42020152795.

Oxidative imbalance increases the risk for colonic polyp and colorectal cancer development

BACKGROUND

The role of oxidative stress in the pathogenesis of colorectal carcinoma (CRC) has garnered considerable interest recently. Specific oxidative factors have been implicated in the pathogenesis of adenomatous polyps and ultimately adenocarcinoma.

AIM

To evaluate the effect of oxidative imbalance as quantified by specific serological markers in the development of sporadic colon adenocarcinoma.

METHODS

A total of 170 patients that underwent endoscopy of the lower gastrointestinal tract in a tertiary center within 3 years were included in the study. They were allocated in three groups; those with sporadic colon adenocarcinoma (n = 56, 32.9%), those with colonic polyps (n = 33, 19.4%) and healthy controls (n = 81, 47.7%). All patients were evaluated for oxidant activity and antioxidant capacity with serum measurements of specific markers such as vitamins A, 25(OH) D3, E, C, B12, folic acid, glutathione, selenium (Se), zinc (Zn), free iron (Fe²⁺), and malondialdehyde and results were compared between groups.

RESULTS

Serum levels of vitamins C, E, D, Se, Zn, vitamin B12 and total antioxidant capacity were significantly lower in the combined neoplasia/polyp group than in the control group (P = 0.002, P = 0.009, P < 0.001, P < 0.001, P < 0.001, P = 0.020 and P < 0.001, correspondingly). Increased levels of vitamin E (P = 0.004), vitamin D (P < 0.001), Se (P < 0.001) and Zn (P < 0.001) seem to bestow a protective effect on the development of CRC. For vitamin D (P < 0.001) and Zn (P = 0.036), this effect seems to extend to the development of colon polyps as well. On the other hand, elevated serum levels of malondialdehyde are associated with a higher risk of CRC (OR = 2.09 compared to controls, P = 0.004). Regarding colonic polyp development, increased concentrations of vitamin Α and Fe²⁺ are associated with a higher risk, whereas lower levels of malondialdehyde with a lower risk.

CONCLUSION

Increased oxidative stress may play an important role in the pathogenesis and progression of CRC. Antioxidants’ presence may exert a protective effect in the very early stages of colon carcinogenesis.

Evaluating Risk: Benefit Ratio of Fat-Soluble Vitamin Supplementation to SARS-CoV-2-Infected Autoimmune and Cancer Patients: Do Vitamin-Drug Interactions Exist?

COVID-19 is a recent pandemic that mandated the scientific society to provide effective evidence-based therapeutic approaches for the prevention and treatment for such a global threat, especially to those patients who hold a higher risk of infection and complications, such as patients with autoimmune diseases and cancer. Recent research has examined the role of various fat-soluble vitamins (vitamins A, D, E, and K) in reducing the severity of COVID-19 infection. Studies showed that deficiency in fat-soluble vitamins abrogates the immune system, thus rendering individuals more susceptible to COVID-19 infection. Moreover, another line of evidence showed that supplementation of fat-soluble vitamins during the course of infection enhances the viral clearance episode by promoting an adequate immune response. However, more thorough research is needed to define the adequate use of vitamin supplements in cancer and autoimmune patients infected with COVID-19. Moreover, it is crucial to highlight the vitamin-drug interactions of the COVID-19 therapeutic modalities and fat-soluble vitamins. With an emphasis on cancer and autoimmune patients, the current review aims to clarify the role of fat-soluble vitamins in SARS-CoV-2 infection and to estimate the risk-to-benefit ratio of a fat-soluble supplement administered to patients taking FDA-approved COVID-19 medications such as antivirals, anti-inflammatory, receptor blockers, and monoclonal antibodies.

Serum Selenium, Vitamin A, and Vitamin E Levels of Healthy Individuals in High- and Low-Risk Areas of Esophageal Cancer

Background: Esophageal cancer is one of the main causes of cancer mortality in the world. Golestan province, in the northern part of Iran, has the highest esophageal cancer rate in the world. The north and south districts of Golestan province can be classified as low and high-risk areas for esophageal cancer. One of the potential risk factors for esophageal cancer in this population is a nutrient-deficient diet. Dietary antioxidant compounds such as selenium, vitamin E, vitamin A, and β-carotene are reactive oxygen species (ROC) scavengers that play a key role in cellular responses to oxidative stress and preventing DNA damage. This study aims to compare the serum levels of selenium, vitamin E, and vitamin A in healthy individuals in high and low-risk areas of esophageal cancer. Methods: This study is a population of 242 healthy individuals. Serum selenium levels were assessed by atomic absorption spectroscopy. Vitamin E and A were assessed by reversed-phase high-performance liquid chromatography. Results: Vitamin E levels of healthy individuals in high-risk areas were significantly lower than in low-risk areas, while there was no significant difference between the selenium and vitamin A levels of healthy individuals in high-risk areas and low-risk areas. Also, there was no significant difference between selenium, vitamin E, and vitamin A levels in urban and rural areas and men and women in Golestan province. Conclusion: High levels of selenium with lower levels of vitamin E, along with other risk factors, may be associated with esophageal squamous cell carcinoma in high-risk areas of Golestan province.

Dietary vitamin E and tocopherol isoforms and incident chronic kidney disease: A 30-y follow-up study from young adulthood to midlife

BACKGROUND

The relationship of dietary vitamin E intake with incident chronic kidney disease (CKD) was not clear as yet. We aimed to examine the associations of dietary total vitamin E and tocopherol isoforms intakes with incident CKD in a 30-year follow-up study from young adulthood to midlife.

METHODS

A total of 4038 American adults aged 18-30 years and without reduced estimated glomerular filtration rate (eGFR) were enrolled from Coronary Artery Risk Development in Young Adults study. Diet was evaluated by a validated dietary-history questionnaire at baseline, and after 7 and 20 years later. The study outcome was incident CKD, defined as an eGFR<60 mL/min/1.73 m² or a urinary albumin to creatinine ratio ≥30 mg/g.

RESULTS

During a 30-year follow-up, 642 (15.9%) participants developed incident CKD. Overall, there was a L-shaped relationship between dietary total vitamin E intake and incident CKD (P for non-linearity<0.001). When total vitamin E intake was assessed as quartiles, compared with those in the first quartile (<4.35 mg α-TE/1000 kcal), the adjusted HRs (95%CI) of incident CKD for participants in the fourth quartile (≥9.61 mg α-TE/1000 kcal) was 0.55 (0.40, 0.75). Moreover, higher intakes of beta-tocopherol and gamma-tocopherol were significantly associated with a lower incident CKD. Higher intake of delta-tocopherol was significantly related to a higher incident CKD. And there was no obvious association of alpha-tocopherol intake with incident CKD.

CONCLUSIONS

There were inverse associations of total vitamin E, beta-tocopherol and gamma-tocopherol intakes, a positive association of delta-tocopherol intake, and no obvious association of alpha-tocopherol intake, with incident CKD among American adults.

Inhibition of PD-L1-mediated tumor-promoting signaling is involved in the anti-cancer activity of β-tocotrienol

Programmed death-ligand 1 (PD-L1), a critical immune checkpoint ligand, is commonly overexpressed on the surface of many tumor types including lung and prostate cancer. PD-L1 can exert cancer-promoting activity through either suppressing T cell-mediated immune response or activating tumor-intrinsic signaling. Here, we demonstrated that β-tocotrienol (β-T3), an isomer of vitamin E, effectively inhibited PD-L1 expression both in vitro and in vivo, which was mechanistically associated inactivating JAK2/STAT3 pathway. Down-regulating PD-L1 expression by β-T3 led to enhanced immune response and inactivation of PD-L1-induced tumor-intrinsic signaling, which in turn contributed to its anticancer activity. This study uncovered a novel mechanism involved in the anticancer effect of β-T3.

Vitamin E Enhances Cancer Immunotherapy by Reinvigorating Dendritic Cells via Targeting Checkpoint SHP1

Despite the popular use of dietary supplements during conventional cancer treatments, their impacts on the efficacies of prevalent immunotherapies, including immune-checkpoint therapy (ICT), are unknown. Surprisingly, our analyses of electronic health records revealed that ICT-treated patients with cancer who took vitamin E (VitE) had significantly improved survival. In mouse models, VitE increased ICT antitumor efficacy, which depended on dendritic cells (DC). VitE entered DCs via the SCARB1 receptor and restored tumor-associated DC functionality by directly binding to and inhibiting protein tyrosine phosphatase SHP1, a DC-intrinsic checkpoint. SHP1 inhibition, genetically or by VitE treatment, enhanced tumor antigen cross-presentation by DCs and DC-derived extracellular vesicles (DC-EV), triggering systemic antigen-specific T-cell antitumor immunity. Combining VitE with DC-recruiting cancer vaccines or immunogenic chemotherapies greatly boosted ICT efficacy in animals. Therefore, combining VitE supplement or SHP1-inhibited DCs/DC-EVs with DC-enrichment therapies could substantially augment T-cell antitumor immunity and enhance the efficacy of cancer immunotherapies.

SIGNIFICANCE

The impacts of nutritional supplements on responses to immunotherapies remain unexplored. Our study revealed that dietary vitamin E binds to and inhibits DC checkpoint SHP1 to increase antigen presentation, prime antitumor T-cell immunity, and enhance immunotherapy efficacy. VitE-treated or SHP1-silenced DCs/DC-EVs could be developed as potent immunotherapies. This article is highlighted in the In This Issue feature, p. 1599.

Cruciferous Vegetables and Their Bioactive Metabolites: from Prevention to Novel Therapies of Colorectal Cancer

The Brassicaceae family, known as cruciferous vegetables, includes many economically important species, mainly edible oil plants, vegetable species, spice plants, and feed plants. Cruciferous vegetables are foods rich in nutritive composition and are also a good source of dietary fiber. Besides, cruciferous vegetables contain various bioactive chemicals known as glucosinolates and S-methyl cysteine sulfoxide, including sulphur-containing cancer-protective chemicals. Numerous studies have reported that daily intake of sulphurous vegetables helps prevent cancer formation and reduces cancer incidence, especially in colorectal cancer, through various mechanisms. The potential mechanisms of these compounds in preventing cancer in experimental studies are as follows: protecting cells against DNA damage, inactivating carcinogenic substances, showing antiviral and antibacterial effects, triggering apoptosis in cells with disrupted structure, inhibiting tumour cell migration causing metastasis and the development of tumour-feeding vessels (angiogenesis). These beneficial anticancer effects of cruciferous vegetables are generally associated with glucosinolates in their composition and some secondary metabolites, as well as other phenolic compounds, seed oils, and dietary fiber in the literature. This review aims to examine to the roles of cruciferous vegetables and their important bioactive metabolites in the prevention and treatment of colorectal cancer.

Exploring the Role of Metabolites in Cancer and the Associated Nerve Crosstalk

Since Otto Warburg's first report on the increased uptake of glucose and lactate release by cancer cells, dysregulated metabolism has been acknowledged as a hallmark of cancer that promotes proliferation and metastasis. Over the last century, studies have shown that cancer metabolism is complex, and by-products of glucose and glutamine catabolism induce a cascade of both pro- and antitumorigenic processes. Some vitamins, which have traditionally been praised for preventing and inhibiting the proliferation of cancer cells, have also been proven to cause cancer progression in a dose-dependent manner. Importantly, recent findings have shown that the nervous system is a key player in tumor growth and metastasis via perineural invasion and tumor innervation. However, the link between cancer-nerve crosstalk and tumor metabolism remains unclear. Here, we discuss the roles of relatively underappreciated metabolites in cancer-nerve crosstalk, including lactate, vitamins, and amino acids, and propose the investigation of nutrients in cancer-nerve crosstalk based on their tumorigenicity and neuroregulatory capabilities. Continued research into the metabolic regulation of cancer-nerve crosstalk will provide a more comprehensive understanding of tumor mechanisms and may lead to the identification of potential targets for future cancer therapies.

Are Vitamin E Supplementation Beneficial for Female Gynaecology Health and Diseases?

Vitamin E is known as an essential vitamin, and many studies had demonstrated the importance of vitamin E throughout the reproductive process, such as miscarriage, premature birth, preeclampsia, and intrauterine growth restriction, which could be caused by a lack of vitamin E during pregnancy. Its potent antioxidant properties can counteract the oxidative stress induced by oxygen free radicals and imbalance of oxidative-antioxidant levels, hence it may play a role in maintaining the normal function of the female reproductive system. Despite the fact that vitamin E is acknowledged as the substance needed for reproduction, its beneficial effects on female fertility, gynaecological health, and diseases are still poorly understood and lacking. Therefore, the goal of this paper is to provide a summary of the known roles of vitamin E supplementation in women for gynaecological health and reproductive-related diseases, as well as its future perspective.

δ-Tocopherol derivatives from the leaves of Muntingia calabura L

From an ethyl acetate-soluble fraction of the leaves of Muntingia calabura, one new trimeric δ-tocopherol derivative named as tocomuntin A (1), together with three known δ-tocopherol derivatives (2-4) were isolated. Their structures were elucidated based on the interpretation of NMR and MS spectroscopic data. In this work, δ-tocopherol (3) was found to have α-glucosidase inhibitory activity for the first time (IC₅₀, 47.3 μM).

Chitosan-Decorated PLGA-NPs Loaded with Tannic Acid/Vitamin E Mitigate Colon Cancer via the NF-κB/β-Cat/EMT Pathway

Colon cancer is the second highest contributor of cancer-related deaths throughout the world. Treatment strategies with tannic acid and vitamin E are envisaged as desirable and safe owing to their robust antioxidative and anti-inflammatory potential. In the present report, these bioactives have been nanoencapsulated in poly(d,l-lactide-co-glycolic acid) (PLGA) formulations for maintaining sustained release and ensuring enhanced bioavailability. Capping of nanoparticles (NPs) with chitosan was done for enhanced anticancer efficacy and tumor targeting. CS-PLGA-TA-E, administered intraperitoneally, significantly inhibited tumor number and tumor volume and normalized colon histology in the colon cancer. Tissue distribution studies showed that TA/E content from CS-PLGA-TA-E was present in a higher concentration in the tumor tissue than the concentration of TA/E content from PLGA-TA-E or free TA or free E. Also, the TA/E content from all of the treatment groups showed its highest concentration in the tumor compared to other organs. Antioxidant enzymes and proinflammatory cytokines (TNF-α, IL-1β, IL-6) were inhibited by CS-PLGA-TA-E. CS-PLGA-TA-E inhibited markers for tumor growth (EGFR-PI3K-AKT), inflammation (NF-κB/Stat3), β-catenin signaling (β-catenin, c-myc, cyclin D1), EMT (E-cadherin, N-cadherin, vimentin), and apoptosis (Bcl-2) in a significantly greater way as compared with PLGA-TA-E, TA, or E. CS-PLGA-TA-E NPs can be considered promising anticancer drugs for colon cancer.

Vitamins as Possible Cancer Biomarkers: Significance and Limitations

The Western-style diet, which is common in developed countries and spreading into developing countries, is unbalanced in many respects. For instance, micronutrients (vitamins A, B complex, C, D, E, and K plus iron, zinc, selenium, and iodine) are generally depleted in Western food (causing what is known as ‘hidden hunger’), whereas some others (such as phosphorus) are added beyond the daily allowance. This imbalance in micronutrients can induce cellular damage that can increase the risk of cancer. Interestingly, there is a large body of evidence suggesting a strong correlation between vitamin intake as well as vitamin blood concentrations with the occurrence of certain types of cancer. The direction of association between the concentration of a given vitamin and cancer risk is tumor specific. The present review summarized the literature regarding vitamins and cancer risk to assess whether these could be used as diagnostic or prognostic markers, thus confirming their potential as biomarkers. Despite many studies that highlight the importance of monitoring vitamin blood or tissue concentrations in cancer patients and demonstrate the link between vitamin intake and cancer risk, there is still an urgent need for more data to assess the effectiveness of vitamins as biomarkers in the context of cancer. Therefore, this review aims to provide a solid basis to support further studies on this promising topic.

Mitigation of late cardiovascular effects of oxygen ion radiation by γ-tocotrienol in a mouse model

PURPOSE

While there is concern about degenerative tissue effects of exposure to space radiation during deep-space missions, there are no pharmacological countermeasures against these adverse effects. γ-Tocotrienol (GT3) is a natural form of vitamin E that has anti-oxidant properties, modifies cholesterol metabolism, and has anti-inflammatory and endothelial cell protective properties. The purpose of this study was to test whether GT3 could mitigate cardiovascular effects of oxygen ion (¹⁶O) irradiation in a mouse model.

MATERIALS AND METHODS

Male C57BL/6 J mice were exposed to whole-body ¹⁶O (600 MeV/n) irradiation (0.26-0.33 Gy/min) at doses of 0 or 0.25 Gy at 6 months of age and were followed up to 9 months after irradiation. Animals were administered GT3 (50 mg/kg/day s.c.) or vehicle, on Monday - Friday starting on day 3 after irradiation for a total of 16 administrations. Ultrasonography was used to measure in vivo cardiac function and blood flow parameters. Cardiac tissue remodeling and inflammatory infiltration were assessed with histology and immunoblot analysis at 2 weeks, 3 and 9 months after radiation.

RESULTS

GT3 mitigated the effects of ¹⁶O radiation on cardiac function, the expression of a collagen type III peptide, and markers of mast cells, T-cells and monocytes/macrophages in the left ventricle.

CONCLUSIONS

GT3 may be a potential countermeasure against late degenerative tissue effects of high-linear energy transfer radiation in the heart.

Different forms of vitamin E and metabolite 13'-carboxychromanols inhibit cyclooxygenase-1 and its catalyzed thromboxane in platelets, and tocotrienols and 13'-carboxychromanols are competitive inhibitors of 5-lipoxygenase

Cyclooxygenase (COX-1 and COX-2)- and 5-lipoxygenase (5-LOX)-catalyzed biosynthesis of eicosanoids play important roles in inflammation and chronic diseases. The vitamin E family has four tocopherols and tocotrienols. We have shown that the metabolites of δ-tocopherol (δT) and δ-tocotrienol (δTE), i.e., δT-13'-carboxychromanol (COOH) and δTE-13'-COOH, respectively, inhibit COX-1/-2 and 5-LOX activity, but the nature of how they inhibit 5-LOX is not clear. Further, the impact of tocopherols and tocotrienols on COX-1/-2 or 5-LOX activity has not been fully delineated. In this study, we found that tocopherols and tocotrienols inhibited human recombinant COX-1 with IC50s of 1-12 µM, and suppressed COX-1-mediated formation of thromboxane in collagen-stimulated rat's platelets with IC50s of 8-50 µM. None of the vitamin E forms directly inhibited COX-2 activity. 13'-COOHs inhibited COX-1 and COX-2 enzyme activity with IC50s of 3-4 and 4-10 µM, respectively, blocked thromboxane formation in collagen- and ionophore-stimulated rats' platelets with IC50s of 1.5-2.5 µM, and also inhibited COX-2-mediated prostaglandins in stimulated cells. Using enzyme kinetics, we observed that δT-13'-COOH, δTE-13'-COOH and δTE competitively inhibited 5-LOX activity with Ki of 1.6, 0.8 and 2.2 µM, respectively. These compounds decreased leukotriene B₄ from stimulated neutrophil-like cells without affecting translocation of 5-LOX from cytosol to the nucleus. Our study reveals inhibitory effects of vitamin E forms and 13'-COOHs on COX-1 activity and thromboxane formation in platelets, and elucidates mechanisms underlying their inhibition of 5-LOX. These observations are useful for understanding the role of these compounds in disease prevention and therapy.

Nutrients and bioactives in citrus fruits: Different citrus varieties, fruit parts, and growth stages

Citrus fruits are consumed in large quantities worldwide due to their attractive aromas and taste, as well as their high nutritional values and various health-promoting effects, which are due to their abundance of nutrients and bioactives. In addition to water, carbohydrates, vitamins, minerals, and dietary fibers are important nutrients in citrus, providing them with high nutritional values. Citrus fruits are also rich in various bioactives such as flavonoids, essential oils, carotenoids, limonoids, and synephrines, which protect from various ailments, including cancer and inflammatory, digestive, and cardiovascular diseases. The composition and content of nutrients and bioactives differ significantly among citrus varieties, fruit parts, and growth stages. To better understand the nutrient and bioactive profiles of citrus fruits and provide guidance for the utilization of high-value citrus resources, this review systematically summarizes the nutrients and bioactives in citrus fruit, including their contents, structural characteristics, and potential health benefits. We also explore the composition variation in different citrus varieties, fruits parts, and growth stages, as well as their health-promoting effects and applications.

Tocotrienols as an Anti-Breast Cancer Agent

In the past few years, breast cancer has become the most prevalent type of cancer. The majority of patients receive combinatorial chemotherapy treatments, which may result in increased risk of developing drug resistance, a reduced quality of life, and substantial side effects. Treatment modalities that could lessen the physical toll of standard treatments or act in synergy with chemotherapeutic treatments would benefit women worldwide. Research into tocotrienols has thus far demonstrated their potential to be such an agent, with tocotrienols surpassing the pharmacological potential of tocopherols. Further research using in vitro and preclinical breast cancer models to support clinical trials is needed. This review uses bibliometric analysis to highlight this gap in research and summarizes the current and future landscape of tocotrienols as an anti-breast cancer agent.

Role of Vitamin E in Selected Malignant Neoplasms in Women

Vitamin E, which is actually a mixture of eight isoforms (four tocopherols and four tocotrienols), is a powerful antioxidant that protects polyunsaturated fatty acids against oxidation and has the ability to break the chain lipid peroxidation, which is used in the treatment of heart disease, atherosclerosis, muscle disorders or infertility among men. Studies in-vitro show that one of the effects of tocopherol is the reduction of cancer stem cell activity which is connected to poor clinical course. In the scientific literature, reports on the participation of vitamin E not only in protection against the mutagenic effects of reactive oxygen species, but also in its anti-angiogenic activity and the ability to inhibit the invasion and metastasis of neoplastic cells are increasingly common. In this context, the role of vitamin E in preventing the neoplastic process and selected malignant neoplasms among women seems to be of particular interest. In this article, we present the results of research on the potential anticancer effects of vitamin E in the fight against breast, cervical, endometrial and ovarian cancer.

Histopathological prognosis of papillary thyroid carcinoma associated with nutritional status of vitamins A and E

BACKGROUND/OBJECTIVES

Experimental and clinical studies have shown that vitamins A and E can inhibit cancer formation and progression. The unfavourable status of these vitamins can represent risk factors for the disease. This study aimed to evaluate the associations between the nutritional status of vitamins A and E (serum levels and dietary intake) and histopathological outcomes in Papillary Thyroid Carcinoma (PTC) patients.

SUBJECTS/METHODS

We applied a cross-sectional study (2017-2018) and quantified retinol (ROH) and α-tocopherol (TOH) serum levels and vitamins dietary intake of 46 PTC patients. Serum vitamins were quantified by high efficiency liquid chromatography and vitamins dietary intake was analyzed by 24-hr dietary recalls.

RESULTS

Patients with lower ROH serum levels were more likely to present lymph node metastasis and/or angiolymphatic invasion (p = 0.025). In addition, higher vitamin A and vitamin E intake are related to the absence of extrathyroidal extension (p = 0.013) and lymph node metastasis (p = 0.007), respectively. Our findings suggest that a ROH serum level greater than 2.65 μmol/L in PTC patients may be a protective factor against the presence of lymph node metastasis and angiolymphatic invasion. In addition, vitamin A and E intake may protect against extrathyroidal extension and lymph node metastasis.

CONCLUSIONS

A favourable nutritional status (higher serum levels and/or intake) of vitamin A and E may be associated with less aggressive tumours in PTC patients.

Phytocompounds Targeting Metabolic Reprogramming in Cancer: An Assessment of Role, Mechanisms, Pathways, and Therapeutic Relevance

The metabolism of cancer is remarkably different from that of normal cells and confers a variety of benefits, including the promotion of other cancer hallmarks. As the rewired metabolism is a near-universal property of cancer cells, efforts are underway to exploit metabolic vulnerabilities for therapeutic benefits. In the continued search for safer and effective ways of cancer treatment, structurally diverse plant-based compounds have gained substantial attention. Here, we present an extensive assessment of the role of phytocompounds in modulating cancer metabolism and attempt to make a case for the use of plant-based compounds in targeting metabolic vulnerabilities of cancer. We discuss the pharmacological interactions of phytocompounds with major metabolic pathways and evaluate the role of phytocompounds in the regulation of growth signaling and transcriptional programs involved in the metabolic transformation of cancer. Lastly, we examine the potential of these compounds in the clinical management of cancer along with limitations and challenges.

Tocopherols and Tocotrienols-Bioactive Dietary Compounds; What Is Certain, What Is Doubt?

Tocopherols and tocotrienols are natural compounds of plant origin, available in the nature. They are supplied in various amounts in a diet, mainly from vegetable oils, some oilseeds, and nuts. The main forms in the diet are α- and γ-tocopherol, due to the highest content in food products. Nevertheless, α-tocopherol is the main form of vitamin E with the highest tissue concentration. The α- forms of both tocopherols and tocotrienols are considered as the most metabolically active. Currently, research results indicate also a greater antioxidant potential of tocotrienols than tocopherols. Moreover, the biological role of vitamin E metabolites have received increasing interest. The aim of this review is to update the knowledge of tocopherol and tocotrienol bioactivity, with a particular focus on their bioavailability, distribution, and metabolism determinants in humans. Almost one hundred years after the start of research on α-tocopherol, its biological properties are still under investigation. For several decades, researchers' interest in the biological importance of other forms of vitamin E has also been growing. Some of the functions, for instance the antioxidant functions of α- and γ-tocopherols, have been confirmed in humans, while others, such as the relationship with metabolic disorders, are still under investigation. Some studies, which analyzed the biological role and mechanisms of tocopherols and tocotrienols over the past few years described new and even unexpected cellular and molecular properties that will be the subject of future research.

Utilization of redox modulating small molecules that selectively act as pro-oxidants in cancer cells to open a therapeutic window for improving cancer therapy

There is a rapidly growing body of literature supporting the notion that differential oxidative metabolism in cancer versus normal cells represents a metabolic frailty that can be exploited to open a therapeutic window into cancer therapy. These cancer cell-specific metabolic frailties may be amenable to manipulation with non-toxic small molecule redox active compounds traditionally thought to be antioxidants. In this review we describe the potential mechanisms and clinical applicability in cancer therapy of four small molecule redox active agents: melatonin, vitamin E, selenium, and vitamin C. Each has shown the potential to have pro-oxidant effects in cancer cells while retaining antioxidant activity in normal cells. This dichotomy can be exploited to improve responses to radiation and chemotherapy by opening a therapeutic window based on a testable biochemical rationale amenable to confirmation with biomarker studies during clinical trials. Thus, the unique pro-oxidant/antioxidant properties of melatonin, vitamin E, selenium, and vitamin C have the potential to act as effective adjuvants to traditional cancer therapies, thereby improving cancer patient outcomes.

Vitamin E Derivative with Modified Side Chain Induced Apoptosis by Modulating the Cellular Lipids and Membrane Dynamics in MCF7 Cells

The vitamin E derivative with side chain modification (TC6OAc) has been shown to possess anticancer activity in our earlier in vivo studies. It was hypothesized that, as Vitamin E (VE) and VE derivative are fat soluble lipophilic molecules, they exert their function by modulating the lipid metabolism and related pathways. This study aimed to evaluate the cellular impact of this VE derivative (2,5,7,8-Tetramethyl-2-(4'-Methyl-3'-Pentenyl)-6-Acetoxy Chromane-TC6OH), using α-tocopherol as a reference compound throughout the experiments. Their effects on the cellular metabolism, the biophysical properties of cellular lipids and the functional characteristics of cells were monitored in human estrogen receptor (ER) positive breast cancer cells. It has been documented that TC6OH treatment induces tumor cell apoptosis by dissipating the mitochondrial membrane potential, modulating the lipid, transportation and degradation as well as downregulating certain anti-apoptotic and growth factor related proteins. Due to resistance of ER positive cells to the established therapies, the findings of this study are of translational value.

γ-Tocotrienol reverses multidrug resistance of breast cancer cells through the regulation of the γ-Tocotrienol-NF-κB-P-gp axis

The problem of multidrug resistance (MDR) presents a major obstacle in the chemotherapy of cancer. The MDR phenotype is often linked to the overexpression of ATP-binding cassette (ABC) transporters, that pumps out and decreased intracellular drug accumulation. γ-Tocotrienol, an unsaturated tocopherol belonging to the vitamin E family, has been shown to reverse the MDR of MCF-7/Adr cell. To reveal the role of γ-tocotrienol-NF-κB-P-gp axis in the reversal process, the expression level of mdr1/P-gp was determined by real-time PCR and western blot, while NF-κB activity was detected by immunofluorescence and NF-κB transcriptional activity reporter assay. Besides, mdr1 promoter activity and P-gp transport capacity were measured with the effect of γ-tocotrienol and NF-κB agonist/antagonist. Results showed that γ-tocotrienol effectively inhibited the expression levels of mdr1 mRNA and P-gp protein. It is demonstrated that γ-tocotrienol also suppressed mdr1 promoter activity and the efflux activity of P-gp. In addition, the activation of NF-κB signaling pathway and the transcriptional activity of NF-κB were both reduced by γ-tocotrienol. Evidences also showed that the NF-κB pathway is really involved in the regulation of the expression and function of mdr1/P-gp. Taken together, we confirmed that γ-tocotrienol reversed the MDR of MCF-7/Adr through the signaling pathway of NF-κB and P-gp.

A Potential Role of IL-6/IL-6R in the Development and Management of Colon Cancer

Colorectal cancer (CRC) is the third most frequent cancer worldwide and the second greatest cause of cancer deaths. About 75% of all CRCs are sporadic cancers and arise following somatic mutations, while about 10% are hereditary cancers caused by germline mutations in specific genes. Several factors, such as growth factors, cytokines, and genetic or epigenetic alterations in specific oncogenes or tumor-suppressor genes, play a role during the adenoma-carcinoma sequence. Recent studies have reported an increase in interleukin-6 (IL-6) and soluble interleukin-6 receptor (sIL-6R) levels in the sera of patients affected by colon cancer that correlate with the tumor size, suggesting a potential role for IL-6 in colon cancer progression. IL-6 is a pleiotropic cytokine showing both pro- and anti-inflammatory roles. Two different types of IL-6 signaling are known. Classic IL-6 signaling involves the binding of IL-6 to its membrane receptor on the surfaces of target cells; alternatively, IL-6 binds to sIL-6R in a process called IL-6 trans-signaling. The activation of IL-6 trans-signaling by metalloproteinases has been described during colon cancer progression and metastasis, involving a shift from membrane-bound interleukin-6 receptor (IL-6R) expression on the tumor cell surface toward the release of soluble IL-6R. In this review, we aim to shed light on the role of IL-6 signaling pathway alterations in sporadic colorectal cancer and the development of familial polyposis syndrome. Furthermore, we evaluate the possible roles of IL-6 and IL-6R as biomarkers useful in disease follow-up and as potential targets for therapy, such as monoclonal antibodies against IL-6 or IL-6R, or a food-based approach against IL-6.

Vitamin E beyond Its Antioxidant Label

Vitamin E, comprising tocopherols and tocotrienols, is mainly known as an antioxidant. The aim of this review is to summarize the molecular mechanisms and signaling pathways linked to inflammation and malignancy modulated by its vitamers. Preclinical reports highlighted a myriad of cellular effects like modulating the synthesis of pro-inflammatory molecules and oxidative stress response, inhibiting the NF-κB pathway, regulating cell cycle, and apoptosis. Furthermore, animal-based models have shown that these molecules affect the activity of various enzymes and signaling pathways, such as MAPK, PI3K/Akt/mTOR, JAK/STAT, and NF-κB, acting as the underlying mechanisms of their reported anti-inflammatory, neuroprotective, and anti-cancer effects. In clinical settings, not all of these were proven, with reports varying considerably. Nonetheless, vitamin E was shown to improve redox and inflammatory status in healthy, diabetic, and metabolic syndrome subjects. The anti-cancer effects were inconsistent, with both pro- and anti-malignant being reported. Regarding its neuroprotective properties, several studies have shown protective effects suggesting vitamin E as a potential prevention and therapeutic (as adjuvant) tool. However, source and dosage greatly influence the observed effects, with bioavailability seemingly a key factor in obtaining the preferred outcome. We conclude that this group of molecules presents exciting potential for the prevention and treatment of diseases with an inflammatory, redox, or malignant component.

Nutritional supplements in the management of oral mucositis in patients with head and neck cancer: Narrative literary review

BACKGROUND AND AIMS

Oral mucositis is the most common side effect in response to anticancer therapies in the head and neck region. It has a debilitating potential for the health of affected individuals, negatively interfering with nutritional status and quality of life. Due to the great complexity of its pathogenicity, different forms of interventions for prevention and treatment are being studied, including nutritional supplements with vitamin E, zinc and glutamine. This study aimed to review the literature on the influence of nutrients, in supplement form, for prevention and/or treatment of mucositis in patients with head and neck cancer.

METHODS

A survey of studies related to the definition, treatment and prevention of mucositis with nutrients was carried out between January 2018 and July 2019, using the Pubmed, Cochrane Library and Scielo databases. In the end, 61 relevant scientific publications were selected between the years 2004 and 2019.

RESULTS

Nutrients such as vitamin E, glutamine and zinc are forms of supplementation that have positive effects on the manifestation and severity of oral mucositis due to their antioxidant and immunomodulatory properties. However, some studies reveal that antioxidant properties may reduce the effectiveness of antineoplastic therapy.

CONCLUSIONS

This study suggests the effectiveness of vitamin E, zinc and glutamine in preventing and treating oral mucositis. However, the importance of new clinical researches to clarify possible doubts is highlighted, as well as the creation of a protocol that includes the dose, route and time of administration, for greater safety in use.

The Role of Vitamin E in Breast Cancer Treatment and Prevention: Current Perspectives

Background:

Regarding the multifactorial etiology of breast cancer, food choices, as well as dietary intake, are the main modified factors in cancer prevention. In this sense, understanding molecular pathways involved in breast cancer proliferation can help determine the mechanisms of action of organic compounds such as antioxidant vitamins that are known to protect against cancer.

Objective:

Assess the mechanism of action of vitamin E in breast cancer modulation, with emphasis on important markers of tumor development.

Methods:

It is a systematic review carried out in PubMed and Web of Science databases, from the last 5 years, in Portuguese, English and Spanish. The following terms were selected according to The Medical Subject Headings (MeSH): “breast cancer” OR “breast neoplasms”, “tocopherol” OR “tocotrienols” OR “vitamin E”, as equated terms.

Results:

A total of 595 articles were found and 25 were selected according to inclusion criteria. Vitamin E has been related to suppression/overexpression of important tumorigenic pathways, mainly associated with proliferation, energy metabolism, chemosensitivity and invasion/metastasis. Clinical studies of vitamin E supplementation are needed to assess the dose/response effect on breast cancer patients.

Conclusion:

The safety of vitamin E supplementation is still controversial due to current studies design available. However, when vitamin E is supplemented, the dose and therapeutic regimen must be carefully decided, including the route of administration and breast cancer subtypes to enhance desired effects and minimize unwanted side effects.