Vitamin C - A new player in regulation of the cancer epigenome

Vitamin C enhances co-localization of novel TET1 nuclear bodies with both Cajal and PML bodies in colorectal cancer cells

Deregulation of ten-eleven Translocation protein 1 (TET1) is commonly reported to induce imbalances in gene expression and subsequently to colorectal cancer development (CRC). On the other hand, vitamin C (VitC) improves the prognosis of colorectal cancer by reprogramming the cancer epigenome and limiting chemotherapeutic drug resistance events. In this study, we aimed to characterize TET1-specific subcellular compartments and evaluate the effect of VitC on TET1 compartmentalization in colonic tumour cells. We demonstrated that TET1 is concentrated in coarse nuclear bodies (NB) and 5-hydroxymethylcytosine (5hmC) in foci in colorectal cancer cells (HCT116, Caco-2, and HT-29). To our knowledge, this is the first report of a novel intracellular localization profile of TET1 and its demethylation marker, 5hmC, in CRC cells. Interestingly, we found that TET1-NBs frequently interacted with Cajal bodies, but not with promyelocytic leukaemia (PML) bodies. In addition, we report that VitC treatment of HCT116 cells induces 5hmC foci biogenesis and triggers 5hmC marks to form active complexes with nuclear body components, including both Cajal and PML proteins. Our data highlight novel NB-concentrating TET1 in CRC cells and demonstrate that VitC modulates TET1-NBs' interactions with other nuclear structures. These findings reveal novel TET1-dependent cellular functions and potentially provide new insights for CRC management.

Empowering γδ T-cell functionality with vitamin C

Vitamin C (ascorbic acid) is a potent antioxidant and a cofactor for various enzymes including histone demethylases and methylcytosine dioxygenases. Vitamin C also exerts direct cytotoxicity toward selected tumor cells including colorectal carcinoma. Moreover, vitamin C has been shown to impact immune cell differentiation at various levels including maturation and/or functionality of T cells and their progenitors, dendritic cells, B cells, and NK cells. γδ T cells have recently attracted great interest as effector cells for cell-based cancer immunotherapy, due to their HLA-independent recognition of a large variety of tumor cells. While γδ T cells can thus be also applied as an allogeneic off-the-shelf product, it is obvious that the effector function of γδ T cells needs to be optimized to ensure the best possible clinical efficacy. Here we review the immunomodulatory mechanisms of vitamin C with a special focus on how vitamin C enhances the effector function of γδ T cells. We also discuss future directions of how vitamin C can be used in the clinical setting to boost the efficacy of adoptive cell therapies.

Vitamin C Inhibits Lipopolysaccharide-Induced Hyperinflammatory State of Chronic Myeloid Leukemia Cells through Purinergic Signaling and Autophagy

Background: Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by the overproduction of white blood cells, leading to symptoms such as fatigue, infections, and other complications. CML patients must take measures to prevent infections to mitigate the exacerbation of cancer cell proliferation and comorbidities. Methods: This study investigated whether vitamin C can suppress the hyperinflammatory activation of K-562 cells induced by lipopolysaccharide (LPS) and whether purinergic signaling (ATP and P2X7 receptor) and autophagy play a role in it. Two different doses of vitamin C (5 µg/mL and 10 µg/mL) were employed, along with the lysosome inhibitor chloroquine (CQ; 100 µM), administered 2 h prior to LPS stimulation (10 ng/mL) for a duration of 22 h in K-562 cells (3 × 105 cells/mL/well). Results: Both doses of vitamin C reduced the release of interleukin-6 (IL-6) (5 µg/mL, p < 0.01 and 10 µg/mL, p < 0.01) and tumor necrosis factor (TNF) (5 µg/mL, p < 0.01 and 10 µg/mL, p < 0.01) induced by LPS. Furthermore, in LPS + CQ-stimulated cells, vitamin C at a concentration of 10 µg/mL inhibited the expression of LC3-II (p < 0.05). Conversely, both doses of vitamin C led to the release of the anti-inflammatory cytokine interleukin-10 (IL-10) (5 µg/mL, p < 0.01 and 10 µg/mL, p < 0.01), while only the 10 µg/mL dose of vitamin C induced the release of Klotho (10 µg/mL, p < 0.01). In addition, both doses of vitamin C reduced the accumulation of ATP (5 µg/mL, p < 0.01 and 10 µg/mL, p < 0.01) and decreased the expression of the P2X7 receptor at the mRNA level. Conclusions: Vitamin C inhibits the hyperinflammatory state induced by LPS in K-562 cells, primarily by inhibiting the ATP accumulation, P2X7 receptor expression, and autophagy signaling.

Modulatory Effect of Vitamin C on Hypoxia Induced Breast Cancer Stem Cells

Purpose

Eliminating cancer stem cells (CSCs) is a challenge because of their enhanced resistance to anti-cancer drugs. Vitamin C, which is insufficient in patients with higher stages of cancer, has been gaining attention as a potential treatment for human malignancies. Hence this study aimed to analyze the effect of high-dose vitamin C treatment on the gene expression level of HIF-1α, NF-κB1, BAX, and DNMT1 in the MCF7 cells undergoing hypoxia, as an inducer of CSCs characteristics. As a result, vitamin C could be possibly used as a promising therapeutic adjuvant.

Methods

Here we first analyzed the breast CSC population alteration in MCF7 cells following hypoxia induction. Then, we evaluated the impact of vitamin C treatment on the gene expression level of four stemness-related genes in hypoxic MCF7 cells.

Results

Our results indicate that vitamin C could reduce proliferation and stemness states in CSCs possibly by induction of apoptotic markers such as BAX, along with attenuating stemness markers, including NF-κB1, and DNMT1 gene expressions.

Conclusion

According to our findings, vitamin C administration would become a new approach to avoiding the stimulation of CSCs during cancer therapies.

Nano-engineered vitamins as a potential epigenetic modifier against environmental air pollutants

Air pollution has emerged as a serious threat to human health due to close association with spectrum of chronic ailments including cardiovascular disorders, respiratory diseases, nervous system dysfunctions, diabetes and cancer. Exposure to air-borne pollutants along with poor eating behaviours and inferior dietary quality irreversibly impacts epigenomic landscape, leading to aberrant transcriptional control of gene expression which is central to patho-physiology of non-communicable diseases. It is assumed that nutriepigenomic interventions such as vitamins can control such adverse effects through their immediate action on mitochondrial epigenomic-axis. Importantly, the exhaustive clinical utility of vitamins-interceded epigenetic synchronization is not well characterized. Therefore, improving the current limitations linked to stability and bioavailability issues in vitamin formulations is highly warranted. The present review not only sums up the available data on the role of vitamins as potential epigenetic modifiers but also discusses the importance of nano-engineered vitamins as potential epidrugs for dietary and pharmacological intervention to mitigate the long-term effects of air pollution toxicity.

Metabolo-epigenetic interplay provides targeted nutritional interventions in chronic diseases and ageing

Epigenetic modifications are chemical modifications that affect gene expression without altering DNA sequences. In particular, epigenetic chemical modifications can occur on histone proteins -mainly acetylation, methylation-, and on DNA and RNA molecules -mainly methylation-. Additional mechanisms, such as RNA-mediated regulation of gene expression and determinants of the genomic architecture can also affect gene expression. Importantly, depending on the cellular context and environment, epigenetic processes can drive developmental programs as well as functional plasticity. However, misbalanced epigenetic regulation can result in disease, particularly in the context of metabolic diseases, cancer, and ageing. Non-communicable chronic diseases (NCCD) and ageing share common features including altered metabolism, systemic meta-inflammation, dysfunctional immune system responses, and oxidative stress, among others. In this scenario, unbalanced diets, such as high sugar and high saturated fatty acids consumption, together with sedentary habits, are risk factors implicated in the development of NCCD and premature ageing. The nutritional and metabolic status of individuals interact with epigenetics at different levels. Thus, it is crucial to understand how we can modulate epigenetic marks through both lifestyle habits and targeted clinical interventions -including fasting mimicking diets, nutraceuticals, and bioactive compounds- which will contribute to restore the metabolic homeostasis in NCCD. Here, we first describe key metabolites from cellular metabolic pathways used as substrates to "write" the epigenetic marks; and cofactors that modulate the activity of the epigenetic enzymes; then, we briefly show how metabolic and epigenetic imbalances may result in disease; and, finally, we show several examples of nutritional interventions - diet based interventions, bioactive compounds, and nutraceuticals- and exercise to counteract epigenetic alterations.

Redox Signaling Modulates Activity of Immune Checkpoint Inhibitors in Cancer Patients

Although immunotherapy is already a staple of cancer care, many patients may not benefit from these cutting-edge treatments. A crucial field of research now focuses on figuring out how to improve treatment efficacy and assess the resistance mechanisms underlying this uneven response. For a good response, immune-based treatments, in particular immune checkpoint inhibitors, rely on a strong infiltration of T cells into the tumour microenvironment. The severe metabolic environment that immune cells must endure can drastically reduce effector activity. These immune dysregulation-related tumour-mediated perturbations include oxidative stress, which can encourage lipid peroxidation, ER stress, and T regulatory cells dysfunction. In this review, we have made an effort to characterize the status of immunological checkpoints, the degree of oxidative stress, and the part that latter plays in determining the therapeutic impact of immunological check point inhibitors in different neoplastic diseases. In the second section of the review, we will make an effort to assess new therapeutic possibilities that, by affecting redox signalling, may modify the effectiveness of immunological treatment.

Cell signaling pathways based on vitamin C and their application in cancer therapy

Vitamin C, a small organic molecule, is widely found in fruits and vegetables and is an essential nutrient in the human body. Vitamin C is closely associated with some human diseases such as cancer. Many studies have shown that high doses of vitamin C have anti-tumor ability and can target tumor cells in multiple targets. This review will describe vitamin C absorption and its function in cancer treatment. We will review the cellular signaling pathways associated with vitamin C against tumors depending on the different anti-cancer mechanisms. Based on this, we will further describe some applications of the use of vitamin C for cancer treatment in preclinical and clinical trials and the possible adverse events that can occur. Finally, this review also assesses the prospective advantages of vitamin C in oncology treatment and clinical applications.

An overview of vitamins as epidrugs for colorectal cancer prevention

Gene expression altering epigenomic modifications such as DNA methylation, histone modification, and chromosome remodeling is crucial to regulating many biological processes. Several lifestyle factors, such as diet and natural, bioactive food compounds, such as vitamins, modify epigenetic patterns. However, epigenetic dysregulation can increase the risk of many diseases, including cancer. Various studies have provided supporting and contrasting evidence on the relationship between vitamins and cancer risk. Though there is a gap in knowledge about whether dietary vitamins can induce epigenetic modifications in the context of colorectal cancer (CRC), the possibility of using them as epidrugs for CRC treatment is being explored. This is promising because such studies might be informative about the most effective way to use vitamins in combination with DNA methyltransferase inhibitors and other approved therapies to prevent and treat CRC. This review summarizes the available epidemiological and observational studies involving dietary, circulating levels, and supplementation of vitamins and their relationship with CRC risk. Additionally, using available in vitro, in vivo, and human observational studies, the role of vitamins as potential epigenetic modifiers in CRC is discussed. This review is focused on the action of vitamins as modifiers of DNA methylation because aberrant DNA methylation, together with genetic alterations, can induce the initiation and progression of CRC. Although this review presents some studies with promising results, studies with better study designs are necessary. A thorough understanding of the underlying molecular mechanisms of vitamin-mediated epigenetic regulation of CRC genes can help identify effective therapeutic targets for CRC prevention and treatment.

Vitamin C Suppresses Pancreatic Carcinogenesis through the Inhibition of Both Glucose Metabolism and Wnt Signaling

Cumulative studies have indicated that high-dose vitamin C has antitumor effects against a variety of cancers. However, the molecular mechanisms underlying these inhibitory effects against tumorigenesis and metastasis, particularly in relation to pancreatic cancer, are unclear. Here, we report that vitamin C at high concentrations impairs the growth and survival of pancreatic ductal adenocarcinoma (PDAC) cells by inhibiting glucose metabolism. Vitamin C was also found to trigger apoptosis in a caspase-independent manner. We further demonstrate that it suppresses the invasion and metastasis of PDAC cells by inhibiting the Wnt/β-catenin-mediated epithelial-mesenchymal transition (EMT). Taken together, our results suggest that vitamin C has therapeutic effects against pancreatic cancer.

The role of nutrition in harnessing the immune system: a potential approach to prevent cancer

Cancer is a vital barrier to increase the life expectancy and the foremost cause of death globally. The initial diagnosis and proper management of cancer can expand the survival rate of individuals. This review provides an in-depth investigation of cancer causes symptoms, types of cancer, and worldwide distribution of cancer. The relation between nutrition (i.e., various food items) and cancer is also emphasized to offer a framework of nutrition management in different cancer types. The microbiota is closely associated with the occurrence of cancer. Thus, genomics of intestinal microbes and nutrigenomics have been discussed based on the reported meta-analysis studies. A dramatic increase in cancer rates has been observed due to intake of alcohol, microbial infections, and deficiency of nutrition. Malnutrition is a substantial problem in cancer patients linked with improper treatment and increased morbidity. The detail studies of cancer and nutrigenomics are an eminent approach to comprehend the relation between microbes and the consumption of certain food types which can further reduce the cancer risk. The incorporation of specific nutrients and probiotics improved the gut microbial health, increased life expectancy, and also decreased the incidence of tumorigenesis in individuals.

The Burden of Cancer, Government Strategic Policies, and Challenges in Pakistan: A Comprehensive Review

Cancer is a severe condition characterized by uncontrolled cell division and increasing reported mortality and diagnostic cases. In 2040, an estimated 28.4 million cancer cases are expected to happen globally. In 2020, an estimated 19.3 million new cancer cases (18.1 million excluding non-melanoma skin cancer) had been diagnosed worldwide, with around 10.0 million cancer deaths. Breast cancer cases have increased by 2.26 million, lung cancer by 2.21 million, stomach by 1.089 million, liver by 0.96 million, and colon cancer by 1.93 million. Cancer is becoming more prevalent in Pakistan, with 19 million new cancer cases recorded in 2020. Food adulteration, gutkha, paan, and nutritional deficiencies are major cancer risk factors that interplay with cancer pathogenesis in this country. Government policies and legislation, cancer treatment challenges, and prevention must be revised seriously. This review presents the current cancer epidemiology in Pakistan to better understand cancer basis. It summarizes current cancer risk factors, causes, and the strategies and policies of the country against cancer.

The Anti-Leukemia Effect of Ascorbic Acid: From the Pro-Oxidant Potential to the Epigenetic Role in Acute Myeloid Leukemia

Data derived from high-throughput sequencing technologies have allowed a deeper understanding of the molecular landscape of Acute Myeloid Leukemia (AML), paving the way for the development of novel therapeutic options, with a higher efficacy and a lower toxicity than conventional chemotherapy. In the antileukemia drug development scenario, ascorbic acid, a natural compound also known as Vitamin C, has emerged for its potential anti-proliferative and pro-apoptotic activities on leukemic cells. However, the role of ascorbic acid (vitamin C) in the treatment of AML has been debated for decades. Mechanistic insight into its role in many biological processes and, especially, in epigenetic regulation has provided the rationale for the use of this agent as a novel anti-leukemia therapy in AML. Acting as a co-factor for 2-oxoglutarate-dependent dioxygenases (2-OGDDs), ascorbic acid is involved in the epigenetic regulations through the control of TET (ten-eleven translocation) enzymes, epigenetic master regulators with a critical role in aberrant hematopoiesis and leukemogenesis. In line with this discovery, great interest has been emerging for the clinical testing of this drug targeting leukemia epigenome. Besides its role in epigenetics, ascorbic acid is also a pivotal regulator of many physiological processes in human, particularly in the antioxidant cellular response, being able to scavenge reactive oxygen species (ROS) to prevent DNA damage and other effects involved in cancer transformation. Thus, for this wide spectrum of biological activities, ascorbic acid possesses some pharmacologic properties attractive for anti-leukemia therapy. The present review outlines the evidence and mechanism of ascorbic acid in leukemogenesis and its therapeutic potential in AML. With the growing evidence derived from the literature on situations in which the use of ascorbate may be beneficial in vitro and in vivo, we will finally discuss how these insights could be included into the rational design of future clinical trials.

Vitamin C Deficiency in Patients With Acute Myeloid Leukemia

Vitamin C has been shown to play a significant role in suppressing progression of leukemia through epigenetic mechanisms. We aimed to study the role of vitamin C in acute myeloid leukemia (AML) biology and clinical course. To this purpose, the plasma levels of vitamin C at diagnosis in 62 patients with AML (including 5 cases with acute promyelocytic leukemia, APL),7 with myelodysplastic syndrome (MDS), and in 15 healthy donors (HDs) were studied. As controls, vitamins A and E levels were analysed. Expression of the main vitamin C transporters and of the TET2 enzyme were investigated by a specific RQ-PCR while cytoplasmic vitamin C concentration and its uptake were studied in mononuclear cells (MNCs), lymphocytes and blast cells purified from AML samples, and MNCs isolated from HDs. There were no significant differences in vitamin A and E serum levels between patients and HDs. Conversely, vitamin C concentration was significantly lower in AML as compared to HDs (p&lt;0.0001), inversely correlated with peripheral blast‐counts (p=0.029), significantly increased at the time of complete remission (CR) (p=0.04) and further decreased in resistant disease (p=0.002). Expression of the main vitamin C transporters SLC23A2, SLC2A1 and SLC2A3 was also significantly reduced in AML compared to HDs. In this line, cytoplasmic vitamin C levels were also significantly lower in AML-MNCs versus HDs, and in sorted blasts compared to normal lymphocytes in individual patients. No association was found between vitamin C plasma levels and the mutation profile of AML patients, as well as when considering cytogenetics or 2017 ELN risk stratification groups. Finally, vitamin C levels did not play a predictive role for overall or relapse-free survival. In conclusion, our study shows that vitamin C levels are significantly decreased in patients with AML at the time of initial diagnosis, further decrease during disease progression and return to normal upon achievement of CR. Correspondingly, low intracellular levels may mirror increased vitamin C metabolic consumption in proliferating AML cells.

Prognostic Ability of Enhancer RNAs in Metastasis of Non-Small Cell Lung Cancer

(1) Background: Non-small cell lung cancer (NSCLC) is the most common lung cancer. Enhancer RNA (eRNA) has potential utility in the diagnosis, prognosis and treatment of cancer, but the role of eRNAs in NSCLC metastasis is not clear; (2) Methods: Differentially expressed transcription factors (DETFs), enhancer RNAs (DEEs), and target genes (DETGs) between primary NSCLC and metastatic NSCLC were identified. Prognostic DEEs (PDEEs) were screened by Cox regression analyses and a predicting model for metastatic NSCLC was constructed. We identified DEE interactions with DETFs, DETGs, reverse phase protein arrays (RPPA) protein chips, immunocytes, and pathways to construct a regulation network using Pearson correlation. Finally, the mechanisms and clinical significance were explained using multi-dimensional validation unambiguously; (3) Results: A total of 255 DEEs were identified, and 24 PDEEs were selected into the multivariate Cox regression model (AUC = 0.699). Additionally, the NSCLC metastasis-specific regulation network was constructed, and six key PDEEs were defined (ANXA8L1, CASTOR2, CYP4B1, GTF2H2C, PSMF1 and TNS4); (4) Conclusions: This study focused on the exploration of the prognostic value of eRNAs in the metastasis of NSCLC. Finally, six eRNAs were identified as potential markers for the prediction of metastasis of NSCLC.

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.

Impact of Diets on Response to Immune Checkpoint Inhibitors (ICIs) Therapy against Tumors

Immunotherapy has revolutionized the established therapeutics against tumors. As the major immunotherapy approach, immune checkpoint inhibitors (ICIs) achieved remarkable success in the treatment of malignancies. However, the clinical gains are far from universal and durable, because of the primary and secondary resistance of tumors to the therapy, or side effects induced by ICIs. There is an urgent need to find safe combinatorial strategies that enhance the response of ICIs for tumor treatment. Diets have an excellent safety profile and have been shown to play pleiotropic roles in tumor prevention, growth, invasion, and metastasis. Accumulating evidence suggests that dietary regimens bolster not only the tolerability but also the efficacy of tumor immunotherapy. In this review, we discussed the mechanisms by which tumor cells evade immune surveillance, focusing on describing the intrinsic and extrinsic mechanisms of resistance to ICIs. We also summarized the impacts of different diets and/or nutrients on the response to ICIs therapy. Combinatory treatments of ICIs therapy with optimized diet regimens own great potential to enhance the efficacy and durable response of ICIs against tumors, which should be routinely considered in clinical settings.

The Epigenetic Role of Vitamin C in Neurodevelopment

The maternal diet during pregnancy is a key determinant of offspring health. Early studies have linked poor maternal nutrition during gestation with a propensity for the development of chronic conditions in offspring. These conditions include cardiovascular disease, type 2 diabetes and even compromised mental health. While multiple factors may contribute to these outcomes, disturbed epigenetic programming during early development is one potential biological mechanism. The epigenome is programmed primarily in utero, and during this time, the developing fetus is highly susceptible to environmental factors such as nutritional insults. During neurodevelopment, epigenetic programming coordinates the formation of primitive central nervous system structures, neurogenesis, and neuroplasticity. Dysregulated epigenetic programming has been implicated in the aetiology of several neurodevelopmental disorders such as Tatton-Brown-Rahman syndrome. Accordingly, there is great interest in determining how maternal nutrient availability in pregnancy might affect the epigenetic status of offspring, and how such influences may present phenotypically. In recent years, a number of epigenetic enzymes that are active during embryonic development have been found to require vitamin C as a cofactor. These enzymes include the ten-eleven translocation methylcytosine dioxygenases (TETs) and the Jumonji C domain-containing histone lysine demethylases that catalyse the oxidative removal of methyl groups on cytosines and histone lysine residues, respectively. These enzymes are integral to epigenetic regulation and have fundamental roles in cellular differentiation, the maintenance of pluripotency and development. The dependence of these enzymes on vitamin C for optimal catalytic activity illustrates a potentially critical contribution of the nutrient during mammalian development. These insights also highlight a potential risk associated with vitamin C insufficiency during pregnancy. The link between vitamin C insufficiency and development is particularly apparent in the context of neurodevelopment and high vitamin C concentrations in the brain are indicative of important functional requirements in this organ. Accordingly, this review considers the evidence for the potential impact of maternal vitamin C status on neurodevelopmental epigenetics.

Multiple vitamin co-exposure and mortality risk: A prospective study

BACKGROUND & AIMS

Existing epidemiological studies explored the associations of circulating vitamins and mortality focusing on individual vitamin effects, and controversial findings were obtained. The joint effects of multiple vitamin co-exposure are worth studying. The study aimed to elucidate the associations of circulating vitamins and the joint effects of these vitamins' co-exposure with all-cause and cause-specific mortality risks.

METHODS

We prospectively evaluated the associations of the concentrations of six kinds of vitamins (A, D, E, C, B12 and B9) in serum with risks for all-cause and cause-specific mortalities among U.S. adults. Mortality status and cause of death were determined by NHANES-linked public available files dated up to 31 December 2015. An unsupervised K-means clustering method was used to cluster the participants into several vitamin co-exposure patterns. The Cox proportional hazards model was used for statistical analysis.

RESULTS

A total of 1404 deaths occurred during a median of 10.9 years follow-up among 8295 participants. In multivariable adjustment, increasing levels of vitamin D were associated with reduced all-cause and cause-specific mortality risks. A J-shaped nonlinear exposure-response relationship was observed between all studied vitamins (except for vitamin D) and all-cause mortality risk. Four co-exposure patterns were generated based on the studied vitamins, as follows: low-level exposure (cluster 1), vitamin A/D exposure (cluster 2), water-soluble vitamin exposure (cluster 3) and high-level exposure (cluster 4). Compared with those in cluster 1, participants in cluster 2 had lower all-cause and cancer mortality risks, with hazard ratios (95% confidence intervals [CIs]) of 0.67 (0.53, 0.85) and 0.45 (0.29, 0.71), respectively.

CONCLUSIONS

The findings in this study indicated that high circulating vitamin D levels were associated with reduced mortality risk among U.S. adults. Vitamin co-exposure at moderate levels appropriately contributed to low all-cause and cancer mortality risks. Our findings provided a novel perspective for exploring the joint health effects of multivitamin co-exposure. Future investigations are needed to further unravel the underlying mechanisms of possible vitamin interactions.

The role of vitamin C in epigenetic cancer therapy

The role of vitamin C in the treatment of cancer has been subject to controversy for decades. Within the past 10 years, mechanistic insight into the importance of vitamin C in epigenetic regulation has provided a new rationale for its potential anti-cancer effects. At physiological concentrations, vitamin C is a potent antioxidant and thereby co-factor for a range of enzymes including the Fe(II)- and α-ketoglutarate-dependent dioxygenases that represent some of the most important epigenetic regulators; the ten-eleven translocation (TET) methylcytosine dioxygenases and the Jumonji-C domain-containing histone demethylases. Epigenetic deregulation is a hallmark of many cancers and reduced activity of these enzymes or somatic loss-of-function mutations in the genes encoding them, are observed in many cancer types. The present review outlines the growing literature on the role of vitamin C in epigenetic therapy of cancer. In the vast majority of in vitro, animal and clinical studies included in this review, vitamin C showed ability across cancer types to increase the hydroxylation of 5-methylcytosine to 5-hydroxymethylcytosine catalyzed by the TET enzymes - the first step in DNA demethylation. Most consistently, vitamin C in combination with the class of epigenetic drugs, DNA methyltransferase inhibitors, has demonstrated efficacy in the treatment of hematological malignancies in both preclinical and the limited number of available clinical studies. Yet, the pertinent question of what is the optimal dose of vitamin C in cancer studies remains to be answered. High-quality randomized placebo-controlled trials are needed to determine whether supplementation with vitamin C may benefit subgroups of patients with (pre-)cancer.

Ascorbate is a multifunctional micronutrient whose synthesis is lacking in primates

Ascorbate (vitamin C) is an essential micronutrient in primates, and exhibits multiple physiological functions. In addition to antioxidative action, ascorbate provides reducing power to α-ketoglutarate-dependent non-heme iron dioxygenases, such as prolyl hydroxylases. Demethylation of histones and DNA with the aid of ascorbate results in the reactivation of epigenetically silenced genes. Ascorbate and its oxidized form, dehydroascorbate, have attracted interest in terms of their roles in cancer therapy. The last step in the biosynthesis of ascorbate is catalyzed by l-gulono-γ-lactone oxidase whose gene Gulo is commonly mutated in all animals that do not synthesize ascorbate. One common explanation for this deficiency is based on the increased availability of ascorbate from foods. In fact, pathways for ascorbate synthesis and the detoxification of xenobiotics by glucuronate conjugation share the metabolic processes up to UDP-glucuronate, which prompts another hypothesis, namely, that ascorbate-incompetent animals might have developed stronger detoxification systems in return for their lack of ability to produce ascorbate, which would allow them to cope with their situation. Here, we overview recent advances in ascorbate research and propose that an enhanced glucuronate conjugation reaction may have applied positive selection pressure on ascorbate-incompetent animals, thus allowing them to dominate the animal kingdom.

Metabolic Classification and Intervention Opportunities for Tumor Energy Dysfunction

A comprehensive view of cell metabolism provides a new vision of cancer, conceptualized as tissue with cellular-altered metabolism and energetic dysfunction, which can shed light on pathophysiological mechanisms. Cancer is now considered a heterogeneous ecosystem, formed by tumor cells and the microenvironment, which is molecularly, phenotypically, and metabolically reprogrammable. A wealth of evidence confirms metabolic reprogramming activity as the minimum common denominator of cancer, grouping together a wide variety of aberrations that can affect any of the different metabolic pathways involved in cell physiology. This forms the basis for a new proposed classification of cancer according to the altered metabolic pathway(s) and degree of energy dysfunction. Enhanced understanding of the metabolic reprogramming pathways of fatty acids, amino acids, carbohydrates, hypoxia, and acidosis can bring about new therapeutic intervention possibilities from a metabolic perspective of cancer.

Are the oxidative stress levels in the tumor center and tumor boundary different from those in healthy tissue?

PURPOSE

This study aimed to investigate the relationship between oxidative stress levels in the tumor center, tumor edge, and healthy tissue.

METHODS

This study included a total of 53 patients with head and neck cancer. Samples of 5 × 5 × 5 mm were collected from the tumor center, tumor edge, and the healthy tissue. Total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) values were evaluated. (1) Oxidative stress values in the center and edge of all tumors and in healthy tissues were compared according to localization. (2) Tumors were divided into two groups as malignant (Group 1 [n = 28]: Laryngeal and tongue squamous cell cancers) and benign (Group 2 [n = 25]: Pleomorphic adenoma and Warthin tumors). The groups were compared according to the localization of the tissues.

RESULTS

The TOS value in the tumor edge was significantly higher than those in the tumor center and the healthy tissue. The TAS value in tissue located in the tumor edge was significantly higher than in the healthy tissue. The OSI value in the tumor edge was significantly higher than those in the tumor center and the healthy tissue. In all three localizations (tumor center, tumor edge, and healthy tissue), TOS and OSI values in Group 1 were significantly higher than Group 2.

CONCLUSION

Oxidative stress values in the tumor edge are significantly higher than the center of the tumor and healthy tissue. In malignant tumors, oxidative stress values are significantly higher in all localizations compared to benign tumors.

High-Dose Vitamin C: Preclinical Evidence for Tailoring Treatment in Cancer Patients

Simple Summary

Vitamin C is an indispensable micronutrient in the human diet due to the multiple functions it carries out in the body. Reports of clinical studies have indicated that, when administered at high dosage by the intravenous route, vitamin C may exert beneficial antitumor effects in patients with advanced stage cancers, including those refractory to previous treatment with chemotherapy. The aim of this article is to provide an overview of the current scientific evidence concerning the different mechanisms of action by which high-dose vitamin C may kill tumor cells. A special focus will be given to those mechanisms that provide the rationale basis for tailoring vitamin C treatment according to specific molecular alterations present in the tumor and for the selection of the most appropriate companion drugs.

Abstract

High-dose vitamin C has been proposed as a potential therapeutic approach for patients with advanced tumors who failed previous treatment with chemotherapy. Due to vitamin C complex pharmacokinetics, only intravenous administration allows reaching sufficiently high plasma concentrations required for most of the antitumor effects observed in preclinical studies (>0.250 mM). Moreover, vitamin C entry into cells is tightly regulated by SVCT and GLUT transporters, and is cell type-dependent. Importantly, besides its well-recognized pro-oxidant effects, vitamin C modulates TET enzymes promoting DNA demethylation and acts as cofactor of HIF hydroxylases, whose activity is required for HIF-1α proteasomal degradation. Furthermore, at pharmacological concentrations lower than those required for its pro-oxidant activity (<1 mM), vitamin C in specific genetic contexts may alter the DNA damage response by increasing 5-hydroxymethylcytosine levels. These more recently described vitamin C mechanisms offer new treatment opportunities for tumors with specific molecular defects (e.g., HIF-1α over-expression or TET2, IDH1/2, and WT1 alterations). Moreover, vitamin C action at DNA levels may provide the rationale basis for combination therapies with PARP inhibitors and hypomethylating agents. This review outlines the pharmacokinetic and pharmacodynamic properties of vitamin C to be taken into account in designing clinical studies that evaluate its potential use as anticancer agent.

TET family dioxygenases and the TET activator vitamin C in immune responses and cancer

Vitamin C serves as a cofactor for Fe(II) and 2-oxoglutarate-dependent dioxygenases including TET family enzymes, which catalyze the oxidation of 5-methylcytosine into 5-hydroxymethylcytosine and further oxidize methylcytosines. Loss-of-function mutations in epigenetic regulators such as TET genes are prevalent in hematopoietic malignancies. Vitamin C deficiency is frequently observed in cancer patients. In this review, we discuss the role of vitamin C and TET proteins in cancer, with a focus on hematopoietic malignancies, T regulatory cells, and other immune system cells.

Molecular mechanism for vitamin C-derived C5-glyceryl-methylcytosine DNA modification catalyzed by algal TET homologue CMD1

C⁵-glyceryl-methylcytosine (5gmC) is a novel DNA modification catalyzed by algal TET homologue CMD1 using vitamin C (VC) as co-substrate. Here, we report the structures of CMD1 in apo form and in complexes with VC or/and dsDNA. CMD1 exhibits comparable binding affinities for DNAs of different lengths, structures, and 5mC levels, and displays a moderate substrate preference for 5mCpG-containing DNA. CMD1 adopts the typical DSBH fold of Fe²⁺/2-OG-dependent dioxygenases. The lactone form of VC binds to the active site and mono-coordinates the Fe²⁺ in a manner different from 2-OG. The dsDNA binds to a positively charged cleft of CMD1 and the 5mC/C is inserted into the active site and recognized by CMD1 in a similar manner as the TET proteins. The functions of key residues are validated by mutagenesis and activity assay. Our structural and biochemical data together reveal the molecular mechanism for the VC-derived 5gmC DNA modification by CMD1.

Functional benefit and molecular mechanism of vitamin C against perfluorooctanesulfonate-associated leukemia

Perfluorooctanesulfonate (PFOS) is a persistent pollutant that can induce toxic effects, including leukemia, on blood cells. Vitamin C (VC), a functional nutrient, has been found to possess potent cytoprotective effects. However, there are currently no reports on its ability to treat PFOS-associated leukemia. This study used a molecular networking analysis to reveal the functional action and pharmacological mechanism of VC against PFOS-associated leukemia. The biological informatics findings revealed a total of 17 intersection targets against PFOS-associated leukemia. In addition, seven core-functional targets, including tumor protein p53 (TP53), mitogen-activated protein kinase 1 (MAPK1), estrogen receptor 1 (ESR1), sirtuin 1 (SIRT1), nitric oxide synthase 3 (NOS3), myeloid cell leukemia-1 (MCL1), and telomerase reverse transcriptase (TERT), were screened and identified. Notably, the molecular docking findings indicated that TP53, MAPK1, and ESR1 were potent pharmacological targets of VC against PFOS-associated leukemia. Moreover, the pharmacological functions including biological processes, cell components, and molecular pathways of VC against PFOS-associated leukemia were determined. According to the computational findings, we conclude that VC protects against PFOS-associated leukemia action by suppressing leukemia-associated cell proliferation and tumor growth. The validated genes of TP53, MAPK1, ESR1 may become potential biomarkers for monitoring and treating PFOS-associated leukemia.

Emerging epigenetic therapeutics for myeloid leukemia: modulating demethylase activity with ascorbate

The past decade has seen a proliferation of drugs that target epigenetic pathways. Many of these drugs were developed to treat acute myeloid leukemia, a condition in which dysregulation of the epigenetic landscape is well established. While these drugs have shown promise, critical issues persist. Specifically, patients with the same mutations respond quite differently to treatment. This is true even with highly specific drugs that are designed to target the underlying oncogenic driver mutations. Furthermore, patients who do respond may eventually develop resistance. There is now evidence that epigenetic heterogeneity contributes, in part, to these issues. Cancer cells also have a remarkable capacity to ‘rewire’ themselves at the epigenetic level in response to drug treatment, and thereby maintain expression of key oncogenes. This epigenetic plasticity is a promising new target for drug development. It is therefore important to consider combination therapy in cases in which both driver mutations and epigenetic plasticity are targeted. Using ascorbate as an example of an emerging epigenetic therapeutic, we review the evidence for its potential use in both of these modes. We provide an overview of 2-oxoglutarate dependent dioxygenases with DNA, histone and RNA demethylase activity, focusing on those which require ascorbate as a cofactor. We also evaluate their role in the development and maintenance of acute myeloid leukemia. Using this information, we highlight situations in which the use of ascorbate to restore 2-oxoglutarate dependent dioxygenase activity could prove beneficial, in contrast to contexts in which targeted inhibition of specific enzymes might be preferred. Finally, we discuss how these insights could be incorporated into the rational design of future clinical trials.

Maize bHLH55 functions positively in salt tolerance through modulation of AsA biosynthesis by directly regulating GDP-mannose pathway genes

Ascorbic acid (AsA) is an antioxidant and enzyme co-factor that is vital to plant development and abiotic stress tolerance. However, the regulation mechanisms of AsA biosynthesis in plants remain poorly understood. Here, we report a basic helix-loop-helix 55 (ZmbHLH55) transcription factor that regulates AsA biosynthesis in maize. Analysis of publicly available transcriptomic data revealed that ZmbHLH55 is co-expressed with several genes of the GDP-mannose pathway. Experimental data showed that ZmbHLH55 forms homodimers localized to the cell nuclei, and it exhibits DNA binding and transactivation activity in yeast. Under salt stress conditions, knock down mutant (zmbhlh55) in maize accumulated lower levels of AsA compared with wild type, accompanied by lower antioxidant enzymes activity, shorter root length, and higher malondialdehyde (MDA) level. Gene expression data from the WT and zmbhlh55 mutant, showed that ZmbHLH55 positively regulates the expression of ZmPGI2, ZmGME1, and ZmGLDH, but negatively regulates ZmGMP1 and ZmGGP. Furthermore, ZmbHLH55-overexpressing Arabidopsis, under salt conditions, showed higher AsA levels, increased rates of germination, and elevated antioxidant enzyme activities. In conclusion, these results have identified previously unknown regulation mechanisms for AsA biosynthesis, indicating that ZmbHLH55 may be a potential candidate to enhance plant salt stress tolerance in the future.

A Study on the Effect of Vitamins A and C to Modulate the Expression of NKG2D Ligands in Hepatic and Colon Cancer Cells

Recently, vitamins have been shown to act as epigenetic modifier. Cancer cells exhibit transcriptional downregulation of NK group 2D ligands (NKG2DLs) through repressive methylation and are largely resistant to NK cell-mediated eradication. We herein investigated the potential of recently reported epigenome modifying vitamins A, C, and E in inducing the expression of epigenetically silenced NKG2DLs in cancer cells. Based on the cell viability assay three concentrations, i.e., 25, 50, and 100 µg/ml of all vitamins were selected for treatment. Results showed that treatment of both vitamin A and C significantly upregulates expression of two major NKG2DLs namely MICA and MICB. Simultaneously, both, vitamin A and C significantly reduces the methylation process by downregulating DNA methyltransferases (DNMTs) expression level. Vitamin C, but not vitamin A, significantly upregulates TETs (DNA demethylases) expression. Further, we assessed the impact of both vitamins A and C on S-adenosylmethionine/S-adenosylhomocysteine (SAM/SAH) ratio levels and found no significant changes in SAM/SAH ratio. Overall, we clearly found that both vitamin A and C induces NKG2DLs mostly through repressing the expression of DNMTs, suggesting their potential role in improving the targeting of tumor cells by promoting the engagement and clearance of tumor cells with NK cells.

Methylomic Signatures of High Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) harbours aberrant epigenetic features, including DNA methylation. In this study we delineate pathways and networks altered by DNA methylation and associated with HGSOC initiation and progression to a platinum-resistant state. By including tumours from patients who had been treated with the hypomethylating agent (HMA) guadecitabine, we also addressed the role of HMAs in treatment of HGSOC. Tumours from patients with primary (platinum-naïve) HGSOC (n = 20) were compared to patients with recurrent platinum-resistant HGSOC and enrolled in a recently completed clinical trial (NCT01696032). Human ovarian surface epithelial cells (HOSE; n = 5 samples) served as normal controls. Genome-wide methylation profiles were determined. DNA methyltransferase (DNMT) expression levels were examined by immunohistochemistry and correlated with clinical outcomes. Cancer-related and tumorigenesis networks were enriched among differentially methylated genes (DMGs) in primary OC vs. HOSE. When comparing platinum-resistant and primary tumours, 452 CpG island (CGI)-containing gene promoters acquired DNA methylation; of those loci, decreased (P < 0.01) methylation after HMA treatment was observed in 42% (n = 189 CGI). Stem cell pluripotency and cytokine networks were enriched in recurrent platinum-resistant OC tumours, while drug metabolism and transport-related networks were downregulated in tumours from HMA-treated patients compared to HOSE. Lower DNMT1 and 3B protein levels in pre-treatment tumours were associated with improved progression-free survival. The findings provide important insight into the DNA methylation landscape of HGSOC tumorigenesis, platinum resistance and epigenetic resensitization. Epigenetic reprogramming plays an important role in HGSOC aetiology and contributes to clinical outcomes.

Micronutrients and Breast Cancer Progression: A Systematic Review

Epidemiological studies on micronutrient consumption have reported protective associations in the incidence and/or progression of various cancer types. Supplementation with some of these micronutrients has been analyzed, showing chemoprotection, low toxicity, antiproliferation, and the ability to modify epigenetic signatures in various cancer models. This review investigates the reported effects of micronutrient intake or supplementation in breast cancer progression. A PubMed search was conducted with the keywords "micronutrients breast cancer progression", and the results were analyzed. The selected micronutrients were vitamins (C, D, and E), folic acid, metals (Cu, Fe, Se, and Zn), fatty acids, polyphenols, and iodine. The majority of in vitro models showed antiproliferative, cell-cycle arrest, and antimetastatic effects for almost all the micronutrients analyzed, but these effects do not reflect animal or human studies. Only one clinical trial with vitamin D and one pilot study with molecular iodine showed favorable overall survival and disease-free interval.

Context dependent effects of ascorbic acid treatment in TET2 mutant myeloid neoplasia

Loss-of-function TET2 mutations (TET2^MT) are common in myeloid neoplasia. TET2, a DNA dioxygenase, requires 2-oxoglutarate and Fe(II) to oxidize 5-methylcytosine. TET2^MT thus result in hypermethylation and transcriptional repression. Ascorbic acid (AA) increases dioxygenase activity by facilitating Fe(III)/Fe(II) redox reaction and may alleviate some biological consequences of TET2^MT by restoring dioxygenase activity. Here, we report the utility of AA in the prevention of TET2^MT myeloid neoplasia (MN), clarify the mechanistic underpinning of the TET2-AA interactions, and demonstrate that the ability of AA to restore TET2 activity in cells depends on N- and C-terminal lysine acetylation and nature of TET2^MT. Consequently, pharmacologic modulation of acetyltransferases and histone deacetylases may regulate TET dioxygenase-dependent AA effects. Thus, our study highlights the contribution of factors that may enhance or attenuate AA effects on TET2 and provides a rationale for novel therapeutic approaches including combinations of AA with class I/II HDAC inhibitor or sirtuin activators in TET2^MT leukemia.

Using TET2- and ascorbic acid deficient model systems Guan et al show that long term treatment with ascorbic acid delays myeloid neoplasia in mice and reveal a complex interplay of post-translational modification of lysine residues that modulate TET2 activity in neoplastic evolution.

Mechanisms and Applications of the Anti-cancer Effect of Pharmacological Ascorbic Acid in Cervical Cancer Cells

In recent years, L-ascorbic acid (L-AA), or vitamin C, has been attracting attention as a potential anticancer drug that mediates hydrogen peroxide-induced oxidation and ten-eleven translocation 2-catalyzed DNA demethylation. However, the precise mechanism by which L-AA acts remains unclear. We examined the cytotoxic effects of L-AA or sodium ascorbate in human cervical carcinoma cells by assessing cell viability, expression of cell cycle-related mRNAs and proteins, and mitochondrial functions, and by performing flow cytometric analyses of cell cycle profiles, apoptosis, cell proliferation, and production of reactive oxygen species (ROS). We later tested the effects of ascorbates in combination with two first-line chemotherapeutic drugs, cisplatin, and doxorubicin. At pharmacological concentrations (1–10 mM), L-AA increased ROS levels; decreased levels of several cell cycle-related proteins, including p53, p21, cyclin D1, and phosphorylated histone 3 at serine residue 10; induced DNA damage, as indicated by changes in γH2A.x; decreased levels of the anti-oxidative transcription factor Nrf2; and increased levels of catalase, superoxide dismutase 1, and endoplasmic reticulum stress-related indicators, such as the p-eIF2α/eIF2α ratio and CHOP levels. L-AA also promoted cell proliferation and induced apoptosis and mitochondrial dysfunction. Finally, L-AA increased the susceptibility of HeLa cells to cisplatin and doxorubicin. These findings provide insight into how the adjustment of the cellular ROS status through L-ascorbate (L-AA or sodium ascorbate) administration could potentially synergistically enhance the efficacy of cancer therapies.

Vitamin C: A stem cell promoter in cancer metastasis and immunotherapy

Vitamin C is an electron donor and is involved in a variety of biochemical reactions in stem cell and cancer stem cell, as well as collagen synthesis and the regulation of hypoxia-inducible factor synthesis, which two affect extracellular matrix remodelling and hence cancer metastasis. Specific doses of vitamin C can stop cancer cell glycolysis and block nitroso synthesis, indicating the potential of vitamin C in cancer treatment. Recent studies preliminary revealed Vitamin C enhance the cancer's immune response to anti PD-L1 therapy through multiple indirect approaches. Herein we reviewed the recent function of vitamin C for further research in sequential aspects of cancer stem cell, extracellular matrix remodeling, cancer metastasis and cancer immunotherapy.

Labile iron affects pharmacological ascorbate-induced toxicity in osteosarcoma cell lines

Vitamin C and iron are both important nutrients for humans and involved in several physiological processes. The biological activities of vitamin C and iron are based on their abilities to accept or donate electrons. Although vitamin C is well known as an excellent electron donor in physiological conditions, it also has pro-oxidant properties, especially with catalytic metal iron. Cancer cells have a higher iron requirement than normal cells, which allows pharmacological ascorbate to kill cancer cells selectively. In this study, we demonstrated that the levels of H₂O₂ in cells were significantly raised after treated with pharmacological ascorbate, and intracellular labile iron could increase pharmacological ascorbate-mediated oxidative stress by Fenton reaction. Catalytic metal iron plays opposite roles in and outside cells. Intracellular excess labile iron improved ascorbate-induced toxicity, while the excess labile iron in the medium abolished ascorbate-induced toxicity. Fe³⁺ and Fe²⁺ have the same effect on ascorbate-induced toxicity, but Fe³⁺ chelator deferoxamine (DFO) has a profound inhibition effect than Fe²⁺ chelator 2,2'-bipyridyl (BIP) on ascorbate-induced toxicity. The influence of intracellular labile iron and ascorbate on the ferritin expression may cause selective sensitivity in osteosarcoma cell lines on pharmacological ascorbate. High iron requirement of many cancer cells facilitates pharmacological ascorbate on cancer treatment. In addition, increasing iron content in tumour tissue may be effective strategies to improve the effects of pharmacological ascorbate.

Vitamin C Inhibits Metastasis of Peritoneal Tumors By Preventing Spheroid Formation in ID8 Murine Epithelial Peritoneal Cancer Model

High mortality is associated with exclusively metastasis within the peritoneal cavity among patients with epithelial ovarian cancer that is the most lethal gynecologic cancer. There is an unmet need to develop more effective therapies to prevent metastasis of peritoneal cancer. Multicellular spheroid formation, during which cancer cells migrate and adhere to tumor-associated macrophages, is a critical step of ovarian cancer metastasis. Here, we showed that vitamin C inhibited spheroid formation and metastasis in ID8 ovarian cancer-bearing mice. We further found that vitamin C treatment decreased the levels of M2 macrophages in tumor nodules and suppressed the epithelial-mesenchymal transition (EMT). In vitro studies revealed that vitamin C inhibited proliferation, arrested cell cycle, attenuated migration, and prevented the spheroid formation of ID8 ovarian cancer cells. Vitamin C induced apoptosis of ID8 cells, which was confirmed by membrane potential collapse, cytosolic calcium overload, ATP depletion, and caspase-3 activation in vitamin C-treated cells. Intriguingly, vitamin C treatment caused striking morphological change and apoptosis of macrophages. The presented proof of concept study strategically identifies new anticancer mechanisms of vitamin C.

Rinsing with L-Ascorbic Acid Exhibits Concentration-Dependent Effects on Human Gingival Fibroblast In Vitro Wound Healing Behavior

Vitamin C or L-ascorbic acid has diverse functions in the body, especially healing promotion in tissue injury via participating in the hydroxylation reactions required for collagen formation. Systemic administration of vitamin C plays an important role on gingival fibroblast proliferation and functions. Whether local or rinsing administration of vitamin C alters gingival fibroblast wound healing behavior remains unclear. The aim of this study was to investigate the rinsing effect of vitamin C on gingival fibroblast behavior utilizing an in vitro wound healing model. Primary human gingival fibroblasts isolated from gingival tissue were rinsed with medium containing various concentrations of vitamin C. The rinsing effect of vitamin C on in vitro wound healing was assessed using a scratch test assay. Cell migration, cell viability, and extracellular matrix gene expression were analyzed by transwell migration assay, MTT assay, and real-time RT-PCR, respectively. We found that rinsing with 10 or 20 µg/ml vitamin C significantly increased fibroblast migration (p ≤ 0.05). However, no significant effect was found in the cell viability or in vitro wound healing assays. In contrast, rinsing with 50 µg/ml vitamin C significantly delayed wound closure (p ≤ 0.05). Real-time PCR demonstrated that 50 µg/ml vitamin C significantly increased fibroblast expression of COL1, FN, IL-6, and bFGF. The data demonstrate that rinsing with vitamin C (10/20 µg/ml) accelerates fibroblast migration. However, 50 µg/ml of vitamin C increases the expression of COL1, FN, IL-6, and bFGF, which are related to fibroblast wound healing activity. Prescribing vitamin C with the appropriate duration and drug administration method should be determined to maximize its benefit.

PHLPP2 is a novel biomarker and epigenetic target for the treatment of vitamin C in pancreatic cancer

Epigenetic dysregulations are closely associated with the development of pancreatic ductal adenocarcinoma (PDAC), which is one of the most aggressive malignancies and currently has limited treatment options. Vitamin C (VC), an epigenetic mediator, exerts antitumor effects on several types of cancer. However, the clinical application of VC is limited, particularly in PDAC. Thus, to investigate the antitumor effects and explore the potential clinical application of VC in PDAC, the survival of patients from The Cancer Genome Atlas database were analyzed, and proliferation, apoptosis and migration assays were performed in the present study. It was first established that high expression levels of the sodium‑dependent VC transporter 2, a critical VC transporter, predicted a good prognosis in patients with pancreatic adenocarcinoma. It was further confirmed that VC directly inhibited proliferation, induced apoptosis and suppressed migration of human pancreatic cancer cells. Global 5‑hydroxymethylcytosine (5hmC) content was significantly upregulated in pancreatic cancer cells following VC treatment, predominantly relying on ten‑eleven translocation 2. Furthermore, VC could specifically increase 5hmC levels at the promotor region on PH domain leucine‑rich repeat protein phosphatase 2 (PHLPP2) and enhance PHLPP2 expression levels. When PHLPP2 expression levels were knocked down, VC was able to partially overcome the inhibition of pancreatic cancer cells. These results illustrated a novel and precise mechanism of action of epigenetic alterations that underly the inhibition of VC in pancreatic cancer, and emphasized that PHLPP2 may be a new biomarker and epigenetic target for the clinical treatment of VC in PDAC.

Combination Therapy with Vitamin C Could Eradicate Cancer Stem Cells

Cancer remains one of the most feared and dreaded diseases in this era of modern medicine, claiming the lives of many, and affecting the quality of life of several others around the globe despite major advances in the diagnosis, treatment, palliative care and the immense resources invested into cancer research. While research in cancer has largely focused on the neoplasm/tumor and the cancerous cells that make up the tumor, more recently, the existence, proliferation, differentiation, migration and invasion of cancer stem cells (CSCs) and the role that CSCs play in tumor initiation, progression, metastasis, drug resistance and relapse/recurrence of the disease has gained widespread interest in cancer research. Although the conventional therapeutic approaches such as surgery, chemotherapy and radiation therapy are effective cancer treatments, very often these treatment modalities fail to target the CSCs, which then later become the source of disease recurrence. A majority of the anti-cancer agents target rapidly dividing cancer cells and normal cells and hence, have side effects that are not expected. Targeting CSCs remains a challenge due to their deviant nature with a low proliferation rate and increased drug resistance mechanism. Ascorbic acid/Vitamin C (Vit.C), a potent antioxidant, is a cofactor for several biosynthetic and gene regulatory enzymes and a vital contributor to immune defense of the body, and was found to be deficient in patients with advanced stages of cancer. Vit.C has gained importance in the treatment of cancer due to its ability to modulate the redox status of the cell and influence epigenetic modifications and significant roles in HIF1α signaling. Studies have reported that intravenous administration of Vit.C at pharmacological doses selectively kills tumor cells and targets CSCs when administered along with chemotherapeutic drugs. In the current article, we provide an in-depth review of how Vit.C plays an important role in targeting CSCs and its possible use as an adjuvant, neoadjuvant or co-treatment in the treatment of cancers.

Enhanced Anticancer Effect of Adding Magnesium to Vitamin C Therapy: Inhibition of Hormetic Response by SVCT-2 Activation

l-Ascorbic acid (vitamin C, AA) is known as an antioxidant, but at high concentrations, AA can kill cancer cells through a prooxidant property. Sodium-dependent vitamin C transporter family-2 (SVCT-2) determines the cellular uptake of AA, and the activity of SVCT-2 is directly related to the anticancer activity of AA. Cancer cells that showed high SVCT-2 expression levels were more sensitive to AA treatment than cancer cells with low SVCT-2 expression levels. Cells with low SVCT-2 expression showed a hormetic response to a low dose of AA. Magnesium ions, which are known to activate SVCT-2, could increase the V_max value of SVCT-2, so we investigated whether providing magnesium supplements to cancer cells with low SVCT-2 expression that had shown a hormetic response to AA would elevate the V_max value of SVCT-2, allowing more AA to accumulate. To evaluate the effects of magnesium on cancer cells, MgSO₄ and MgCl₂ were screened as magnesium supplements; both forms showed synergistic anticancer effects with AA. Taken together, the results of this study suggest that magnesium supplementation enhanced the anticancer effect of AA by inhibiting the hormetic response at a low dose. This study has also demonstrated that AA treatment with magnesium supplementation provided more effective anticancer therapy than AA treatment alone.

An integrated spectroscopic strategy to trace the geographical origins of emblic medicines: Application for the quality assessment of natural medicines

Emblic medicine is a popular natural source in the world due to its outstanding healthcare and therapeutic functions. Our preliminary results indicated that the quality of emblic medicines might have an apparent regional variation. A rapid and effective geographical traceability system has not been designed yet. To trace the geographical origins so that their quality can be controlled, an integrated spectroscopic strategy including spectral pretreatment, outlier diagnosis, feature selection, data fusion, and machine learning algorithm was proposed. A featured data matrix (245 × 220) was successfully generated, and a carefully adjusted RF machine learning algorithm was utilized to develop the geographical traceability model. The results demonstrate that the proposed strategy is effective and can be generalized. Sensitivity (SEN), specificity (SPE) and accuracy (ACC) of 97.65%, 99.85% and 97.63% for the calibrated set, as well as 100.00% predictive efficiency, were obtained using this spectroscopic analysis strategy. Our study has created an integrated analysis process for multiple spectral data, which can achieve a rapid, nondestructive and green quality detection for emblic medicines originating from seventeen geographical origins.

Oral vitamin C supplementation to patients with myeloid cancer on azacitidine treatment: Normalization of plasma vitamin C induces epigenetic changes

Background

Patients with haematological malignancies are often vitamin C deficient, and vitamin C is essential for the TET-induced conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), the first step in active DNA demethylation. Here, we investigate whether oral vitamin C supplementation can correct vitamin C deficiency and affect the 5hmC/5mC ratio in patients with myeloid cancers treated with DNA methyltransferase inhibitors (DNMTis).

Results

We conducted a randomized, double-blinded, placebo-controlled pilot trial (NCT02877277) in Danish patients with myeloid cancers performed during 3 cycles of DNMTi-treatment (5-azacytidine, 100 mg/m²/d for 5 days in 28-day cycles) supplemented by oral dose of 500 mg vitamin C (n = 10) or placebo (n = 10) daily during the last 2 cycles. Fourteen patients (70%) were deficient in plasma vitamin C (< 23 μM) and four of the remaining six patients were taking vitamin supplements at inclusion. Global DNA methylation was significantly higher in patients with severe vitamin C deficiency (< 11.4 μM; 4.997 vs 4.656% 5mC relative to deoxyguanosine, 95% CI [0.126, 0.556], P = 0.004). Oral supplementation restored plasma vitamin C levels to the normal range in all patients in the vitamin C arm (mean increase 34.85 ± 7.94 μM, P = 0.0004). We show for the first time that global 5hmC/5mC levels were significantly increased in mononuclear myeloid cells from patients receiving oral vitamin C compared to placebo (0.037% vs − 0.029%, 95% CI [− 0.129, − 0.003], P = 0.041).

Conclusions

Normalization of plasma vitamin C by oral supplementation leads to an increase in the 5hmC/5mC ratio compared to placebo-treated patients and may enhance the biological effects of DNMTis. The clinical efficacy of oral vitamin C supplementation to DNMTis should be investigated in a large randomized, placebo-controlled clinical trial.

Trial registration

ClinicalTrials.gov, NCT02877277. Registered on 9 August 2016, retrospectively registered.

Association of Leukemia Target Genes Tet2, Bcl2, and Slc23a2 in Vitamin C Pathways

BACKGROUND

Vitamin C has been used in combination with several target genes in the treatment of leukemia. Tet methylcytosine dioxygenase (Tet2), B-cell lymphoma 2 (Bcl2), and solute carrier family 23 member 2 (Slc23a2) are the major target genes in the treatment of leukemia and are relevant to vitamin C.

MATERIALS AND METHODS

Using whole-genome expression profiles from mouse livers, the expression quantitative trait locus (eQTL), correlation matrix, and gene network graph were constructed with probes from each of these three genes and with their relative genes. The function of key genes was examined by their pathways and reported information. The results indicated that although direct correlations among their expression levels were not strong, alternative connecting pathways were discovered. By comparing the expression levels of one probe with known sequences from each of the three genes, we identified several key genes, induced myeloid leukemia cell differentiation protein (Mcl1), far upstream element-binding protein 1 (Fubp1), and tumor protein D52-like 2 (Tpd52l2), which play important roles in acute lymphocytic leukemia and acute myelocytic leukemia. In conclusion, Alternative pathways and key genes that connect Tet2, Bcl2, and Slc23a2 for their therapeutic applications with vitamin C were identified.

Novel Strategies for Cancer Treatment: Highlights from the 55th IACR Annual Conference

While conventional cancer treatments, such as surgery, radiotherapy and chemotherapy, have been combined for decades in an effort to treat cancer patients, the emergence of novel fields of cancer research have led to a renewed interest in combining conventional treatments with more innovative approaches. The realisation that cancer progression is not exclusively due to changes in the cancer epithelial cells, but also involves changes in the tumour microenvironment, has opened new avenues for combination treatments. Here we discuss the use of combination therapies presented at the 55th Irish Association for Cancer Research (IACR) Annual Conference, highlighting examples of novel therapeutic strategies which, combined with conventional therapies, may greatly enhance not only the overall outcome for patients, but also the quality of life for cancer survivors. Among the novel treatment strategies, immune metabolism, epigenetic therapies and physical exercise are presented. In addition, novel technologies in the field of precision medicine, which will be useful to discover new therapeutics and to stratify patients for combination treatments, are also discussed.

Biomarkers of Nutrition and Health: New Tools for New Approaches

A main challenge in nutritional studies is the valid and reliable assessment of food intake, as well as its effects on the body. Generally, food intake measurement is based on self-reported dietary intake questionnaires, which have inherent limitations. They can be overcome by the use of biomarkers, capable of objectively assessing food consumption without the bias of self-reported dietary assessment. Another major goal is to determine the biological effects of foods and their impact on health. Systems analysis of dynamic responses may help to identify biomarkers indicative of intake and effects on the body at the same time, possibly in relation to individuals' health/disease states. Such biomarkers could be used to quantify intake and validate intake questionnaires, analyse physiological or pathological responses to certain food components or diets, identify persons with specific dietary deficiency, provide information on inter-individual variations or help to formulate personalized dietary recommendations to achieve optimal health for particular phenotypes, currently referred as "precision nutrition." In this regard, holistic approaches using global analysis methods (omics approaches), capable of gathering high amounts of data, appear to be very useful to identify new biomarkers and to enhance our understanding of the role of food in health and disease.

Targeting cancer vulnerabilities with high-dose vitamin C

Over the past century, the notion that vitamin C can be used to treat cancer has generated much controversy. However, new knowledge regarding the pharmacokinetic properties of vitamin C and recent high-profile preclinical studies have revived interest in the utilization of high-dose vitamin C for cancer treatment. Studies have shown that pharmacological vitamin C targets many of the mechanisms that cancer cells utilize for their survival and growth. In this Opinion article, we discuss how vitamin C can target three vulnerabilities many cancer cells share: redox imbalance, epigenetic reprogramming and oxygen-sensing regulation. Although the mechanisms and predictive biomarkers that we discuss need to be validated in well-controlled clinical trials, these new discoveries regarding the anticancer properties of vitamin C are promising to help identify patient populations that may benefit the most from high-dose vitamin C therapy, developing effective combination strategies and improving the overall design of future vitamin C clinical trials for various types of cancer.