Vitamin B₆ activates p53 and elevates p21 gene expression in cancer cells and the mouse colon

Comparative Analysis of Breast Cancer Metabolomes Highlights Fascin's Central Role in Regulating Key Pathways Related to Disease Progression

Omics technologies provide useful tools for the identification of novel biomarkers in many diseases, including breast cancer, which is the most diagnosed cancer in women worldwide. We and others have reported a central role for the actin-bundling protein (fascin) in regulating breast cancer disease progression at different levels. However, whether fascin expression promotes metabolic molecules that could predict disease progression has not been fully elucidated. Here, fascin expression was manipulated via knockdown (fascinKD+NORF) and rescue (fascinKD+FORF) in the naturally fascin-positive (fascinpos+NORF) MDA-MB-231 breast cancer cells. Whether fascin dysregulates metabolic profiles that are associated with disease progression was assessed using untargeted metabolomics analyses via liquid chromatography-mass spectrometry. Overall, 12,226 metabolic features were detected in the tested cell pellets. Fascinpos+NORF cell pellets showed 2510 and 3804 significantly dysregulated metabolites compared to their fascinKD+NORF counterparts. Fascin rescue (fascinKD+FORF) revealed 2710 significantly dysregulated cellular metabolites compared to fascinKD+NORF counterparts. A total of 101 overlapped cellular metabolites between fascinKD+FORF and fascinpos+NORF were significantly dysregulated in the fascinKD+NORF cells. Analysis of the significantly dysregulated metabolites by fascin expression revealed their involvement in the metabolism of sphingolipid, phenylalanine, tyrosine, and tryptophan biosynthesis, and pantothenate and CoA biosynthesis, which are critical pathways for breast cancer progression. Our findings of fascin-mediated alteration of metabolic pathways could be used as putative poor prognostic biomarkers and highlight other underlying mechanisms of fascin contribution to breast cancer progression.

Vitamin B6 regulates IL-33 homeostasis to alleviate type 2 inflammation

Interleukin-33 (IL-33) is a crucial nuclear cytokine that induces the type 2 immune response and maintains immune homeostasis. The fine-tuned regulation of IL-33 in tissue cells is critical to control of the type 2 immune response in airway inflammation, but the mechanism is still unclear. Here, we found that healthy individuals had higher phosphate-pyridoxal (PLP, an active form of vitamin B6) concentrations in the serum than asthma patients. Lower serum PLP concentrations in asthma patients were strongly associated with worse lung function and inflammation. In a mouse model of lung inflammation, we revealed that PLP alleviated the type 2 immune response and that this inhibitory effect relied on the activity of IL-33. A mechanistic study showed that in vivo, pyridoxal (PL) needed to be converted into PLP, which inhibited the type 2 response by regulating IL-33 stability. In mice heterozygous for pyridoxal kinase (PDXK), the conversion of PL to PLP was limited, and IL-33 levels were increased in the lungs, aggravating type 2 inflammation. Furthermore, we found that the mouse double minute 2 homolog (MDM2) protein, an E3 ubiquitin-protein ligase, could ubiquitinate the N-terminus of IL-33 and sustain IL-33 stability in epithelial cells. PLP reduced MDM2-mediated IL-33 polyubiquitination and decreased the level of IL-33 through the proteasome pathway. In addition, inhalation of PLP alleviated asthma-related effects in mouse models. In summary, our data indicate that vitamin B6 regulates MDM2-mediated IL-33 stability to constrain the type 2 response, which might help develop a potential preventive and therapeutic agent for allergy-related diseases.

Relationship between structure and cytotoxicity of vanadium and molybdenum complexes with pyridoxal derived ligands

In this work four vanadium complexes (compounds 1, 2, 3 and 4) and one molybdenum complex (compound 5) with hydrazone ligands derived from pyridoxal were synthesized and characterized. All compounds are mononuclear species, two of them (compounds 3 and 5) are dioxide complexes and the other three (compounds 1, 2 and 4) monoxide complexes. The vanadium atom of the compound 3 is five-coordinated and all the other compounds have a six coordinated environment polyhedron. The poses for the potential intercalation of the compounds 2 and 3 with DNA were obtained by using AutoDock software. Optimizations were also performed at PM6-D3H4 semi-empirical level whereas the study of the nature of the interaction was carried out by means of the Energy Decomposition Analysis and the Non-Covalent Interaction index by using in both cases Density Functional Theory computations. The cytotoxicity in lung cancer cells (A549 cell line) of all the compounds was also evaluated. After 24 h of treatment, vanadium complexes showed high values of IC₅₀, between 419.93 ± 22.58 and 685.88 ± 46.55 μM. After 48 h, the results showed that the compound 3 had the lowest IC₅₀ value, 65.32 ± 9.95 μM, and the compound 2 the highest value, 375.28 ± 32.09 μM. The molybdenum complex showed the lowest IC₅₀ value at 48 h (11.22 ± 1.34 μM). The toxicity of the compounds 3, 4 and 5 was tested in vivo, using zebrafish model, and the molybdenum complex showed higher toxic effects than the studied vanadium complexes.

Pyridoxine deficiency modulates benzene inhalation-induced hematotoxicity associated with hepatic CYP2E1 activity in B6C3F1 mice

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Modifying effects of pyridoxine deficiency on benzene toxicity were assessed in B6C3F1 mice.

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The mice were fed either a pyridoxine-deficient diet or control diet.

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Pyridoxine deficiency was combined with nose-only benzene inhalation exposure (100 ppm).

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Pyridoxine deficiency and benzene inhalation led to lower body, thymus and spleen weights.

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The treatment combination also led to higher hepatic CYP2E1 protein expression and activity.

Pyridoxine is a co-factor in many enzymatic reactions and impacts of deficiency have been observed in affected populations. A possible modifying effect of pyridoxine deficiency on benzene toxicity was assessed in male B₆C₃F₁ mice fed either a pyridoxine-deficient diet or a control diet. This treatment was combined with benzene inhalation exposure (100 ppm) or no benzene treatment. Pyridoxine-deficient mice exposed to 100 ppm benzene had significantly lower body, thymus and spleen weights. While total white blood cell counts, percentage of lymphocytes, hematocrit and hemoglobin levels were lower, the percentage of neutrophils was significantly higher in deficient and benzene-exposed mice compared to non-exposed controls. Hepatic CYP2E1 protein expression and activity in the deficient and exposed mice were also significantly higher compared to the non-exposed controls. A significant correlation between CYP2E1 activity and several hematological parameters was observed. These results demonstrated that pyridoxine deficiency significantly impacted benzene-induced hematotoxicity. Moreover, the observed agonistic effect of pyridoxinedeficiency and benzene inhalation exposure on CYP2E1 would seem to indicate an involvement of metabolism, but this needs to be further assessed.

Role of Dietary Antioxidants in p53-Mediated Cancer Chemoprevention and Tumor Suppression

Cancer arises through a complex interplay between genetic, behavioral, metabolic, and environmental factors that combined trigger cellular changes that over time promote malignancy. In terms of cancer prevention, behavioral interventions such as diet can promote genetic programs that may facilitate tumor suppression; and one of the key tumor suppressors responsible for initiating such programs is p53. The p53 protein is activated by various cellular events such as DNA damage, hypoxia, heat shock, and overexpression of oncogenes. Due to its role in cell fate decisions after DNA damage, regulatory pathways controlled by p53 help to maintain genome stability and thus “guard the genome” against mutations that cause cancer. Dietary intake of flavonoids, a C₁₅ group of polyphenols, is known to inhibit cancer progression and assist DNA repair through p53-mediated mechanisms in human cells via their antioxidant activities. For example, quercetin arrests human cervical cancer cell growth by blocking the G₂/M phase cell cycle and inducing mitochondrial apoptosis through a p53-dependent mechanism. Other polyphenols such as resveratrol upregulate p53 expression in several cancer cell lines by promoting p53 stability, which in colon cancer cells results in the activation of p53-mediated apoptosis. Finally, among vitamins, folic acid seems to play an important role in the chemoprevention of gastric carcinogenesis by enhancing gastric epithelial apoptosis in patients with premalignant lesions by significantly increased expression of p53. In this review, we discuss the role of these and other dietary antioxidants in p53-mediated cell signaling in relation to cancer chemoprevention and tumor suppression in normal and cancer cells.

B Vitamins and Their Role in Immune Regulation and Cancer

B group vitamins represent essential micronutrients for myriad metabolic and regulatory processes required for human health, serving as cofactors used by hundreds of enzymes that carry out essential functions such as energy metabolism, DNA and protein synthesis and other critical functions. B vitamins and their corresponding vitamers are universally essential for all cellular life forms, from bacteria to humans. Humans are unable to synthesize most B vitamins and are therefore dependent on their diet for these essential micronutrients. More recently, another source of B vitamins has been identified which is derived from portions of the 10¹³ bacterial cells inhabiting the gastrointestinal tract. Here we review the expanding literature examining the relationship between B vitamins and the immune system and diverse cancers. Evidence of B vitamin’s role in immune cell regulation has accumulated in recent years and may help to clarify the disparate findings of numerous studies attempting to link B vitamins to cancer development. Much work remains to be carried out to fully clarify these relationships as the complexity of B vitamins’ essential functions complicates an unequivocal assessment of their beneficial or detrimental effects in inflammation and cancers.

The multifaceted role of vitamin B6 in cancer: Drosophila as a model system to investigate DNA damage

A perturbed uptake of micronutrients, such as minerals and vitamins, impacts on different human diseases, including cancer and neurological disorders. Several data converge towards a crucial role played by many micronutrients in genome integrity maintenance and in the establishment of a correct DNA methylation pattern. Failure in the proper accomplishment of these processes accelerates senescence and increases the risk of developing cancer, by promoting the formation of chromosome aberrations and deregulating the expression of oncogenes. Here, the main recent evidence regarding the impact of some B vitamins on DNA damage and cancer is summarized, providing an integrated and updated analysis, mainly centred on vitamin B₆. In many cases, it is difficult to finely predict the optimal vitamin rate that is able to protect against DNA damage, as this can be influenced by a given individual's genotype. For this purpose, a precious resort is represented by model organisms which allow limitations imposed by more complex systems to be overcome. In this review, we show that Drosophila can be a useful model to deeply understand mechanisms underlying the relationship between vitamin B₆ and genome integrity.

One-carbon metabolites, B vitamins and associations with systemic inflammation and angiogenesis biomarkers among colorectal cancer patients: results from the ColoCare Study

B vitamins involved in one-carbon metabolism have been implicated in the development of inflammation- and angiogenesis-related chronic diseases, such as colorectal cancer (CRC). Yet, the role of one-carbon metabolism in inflammation and angiogenesis among CRC patients remains unclear. The objective of this study was to investigate associations of components of one-carbon metabolism with inflammation and angiogenesis biomarkers among newly diagnosed CRC patients (n 238) in the prospective ColoCare Study, Heidelberg. We cross-sectionally analysed associations between twelve B vitamins and one-carbon metabolites and ten inflammation and angiogenesis biomarkers from pre-surgery serum samples using multivariable linear regression models. We further explored associations among novel biomarkers in these pathways with Spearman partial correlation analyses. We hypothesised that pyridoxal-5'-phosphate (PLP) is inversely associated with inflammatory biomarkers. We observed that PLP was inversely associated with C-reactive protein (CRP) (r -0·33, Plinear < 0·0001), serum amyloid A (SAA) (r -0·23, Plinear = 0·003), IL-6 (r -0·39, Plinear < 0·0001), IL-8 (r -0·20, Plinear = 0·02) and TNFα (r -0·12, Plinear = 0·045). Similar findings were observed for 5-methyl-tetrahydrofolate and CRP (r -0·14), SAA (r -0·14) and TNFα (r -0·15) among CRC patients. Folate catabolite acetyl-para-aminobenzoylglutamic acid (pABG) was positively correlated with IL-6 (r 0·27, Plinear < 0·0001), and pABG was positively correlated with IL-8 (r 0·21, Plinear < 0·0001), indicating higher folate utilisation during inflammation. Our data support the hypothesis of inverse associations between PLP and inflammatory biomarkers among CRC patients. A better understanding of the role and inter-relation of PLP and other one-carbon metabolites with inflammatory processes among colorectal carcinogenesis and prognosis could identify targets for future dietary guidance for CRC patients.

Epigenetic Regulation of Gene Expression Induced by Butyrate in Colorectal Cancer: Involvement of MicroRNA

Colorectal cancer (CRC) is the third most common cause of cancer mortality globally. Development of CRC is closely associated with lifestyle, and diet may modulate risk. A Western-style diet is characterised by a high intake of red meat but low consumption of fruit, vegetables, and whole cereals. Such a diet is associated with CRC risks. It has been demonstrated that butyrate, produced by the fermentation of dietary plant fibre, can alter both genetic and epigenetic expressions. MicroRNAs (miRNAs) are small non-coding RNAs that are commonly present in both normal and tumour cells. Aberrant miRNA expression is associated with CRC initiation, progression, and metastasis. In addition, butyrate can modulate cell proliferation, differentiation, apoptosis, and miRNA expression in CRC. In this review, the effects of butyrate on modulating miRNA expression in CRC will be discussed. Furthermore, evidence on the effect of butyrate on CRC risk through reducing oncogenic miRNA expression will be presented.

Endoplasmic reticulum targeting tumour selective photocytotoxic oxovanadium(IV) complexes having vitamin-B6 and acridinyl moieties

Oxovanadium(iv) complexes of vitamin-B6 Schiff base, viz., [VO(HL(1)/L(2)/L(3))(B)]Cl (), where B is 2,2'-bipyridine (bpy in and ), 11-(9-acridinyl)dipyrido[3,2-a:2',3'-c]phenazine (acdppz in and ), H2L(1)·HCl is 3-hydroxy-5-(hydroxymethyl)-4-(((2-hydroxyphenyl)imino)methyl)-2-methylpyridin-1-ium chloride (in and ), HL(2) is 2-(((2-(1H-imidazol-4-yl)ethyl)imino)methyl)phenol (in ) and HL(3) is 4-(((2-(1H-imidazol-4-yl)ethyl)imino)methyl)-5-(hydroxymethyl)-2-methylpyridin-3-ol (in ) were synthesized, characterized and their cellular uptake, photo-activated cytotoxicity and intracellular localization were studied. Complexes , as the perchlorate salt of , and , as the hexafluorophosphate salt of , were structurally characterized. Vitamin-B6 transporting membrane carrier (VTC) mediated entry into tumour cells in preference to the normal ones seems to be responsible for the higher cellular uptake of the complexes into HeLa and MCF-7 cells over MCF-10A cells. Complexes and having acdppz as the photosensitizer exhibit remarkable photocytotoxicity in these cancer cells giving IC50 of <0.9 μM. The complexes remain non-toxic in the dark. The complexes show photo-induced apoptotic cell death via singlet oxygen ((1)O2) generation. Fluorescence microscopy reveals specific localization of complex to endoplasmic reticulum (ER) and generation of (1)O2 possibly leads to apoptotic cell death by triggering ER stress response (ERSR).

Understanding Metabolic Regulation at a Systems Level: Metabolite Sensing, Mathematical Predictions, and Model Organisms

Metabolic networks are extensively regulated to facilitate tissue-specific metabolic programs and robustly maintain homeostasis in response to dietary changes. Homeostatic metabolic regulation is achieved through metabolite sensing coupled to feedback regulation of metabolic enzyme activity or expression. With a wealth of transcriptomic, proteomic, and metabolomic data available for different cell types across various conditions, we are challenged with understanding global metabolic network regulation and the resulting metabolic outputs. Stoichiometric metabolic network modeling integrated with "omics" data has addressed this challenge by generating nonintuitive, testable hypotheses about metabolic flux rewiring. Model organism studies have also yielded novel insight into metabolic networks. This review covers three topics: the feedback loops inherent in metabolic regulatory networks, metabolic network modeling, and interspecies studies utilizing Caenorhabditis elegans and various bacterial diets that have revealed novel metabolic paradigms.

Metabolic network rewiring of propionate flux compensates vitamin B12 deficiency in C. elegans

Metabolic network rewiring is the rerouting of metabolism through the use of alternate enzymes to adjust pathway flux and accomplish specific anabolic or catabolic objectives. Here, we report the first characterization of two parallel pathways for the breakdown of the short chain fatty acid propionate in Caenorhabditis elegans. Using genetic interaction mapping, gene co-expression analysis, pathway intermediate quantification and carbon tracing, we uncover a vitamin B12-independent propionate breakdown shunt that is transcriptionally activated on vitamin B12 deficient diets, or under genetic conditions mimicking the human diseases propionic- and methylmalonic acidemia, in which the canonical B12-dependent propionate breakdown pathway is blocked. Our study presents the first example of transcriptional vitamin-directed metabolic network rewiring to promote survival under vitamin deficiency. The ability to reroute propionate breakdown according to B12 availability may provide C. elegans with metabolic plasticity and thus a selective advantage on different diets in the wild.

Manipulating miRNA Expression: A Novel Approach for Colon Cancer Prevention and Chemotherapy

Small non-coding RNA has been implicated in the control of various cellular processes such as proliferation, apoptosis, and differentiation. About 50% of the miRNA genes are positioned in cancer-associated genomic regions. Several studies have shown that miRNA expression is deregulated in cancer and modulating their expression has reversed the cancer phenotype. Therefore, mechanisms to modulate microRNA (miRNA) activity have provided a novel opportunity for cancer prevention and therapy. In addition, a common cause for development of colorectal cancers is environmental and lifestyle factors. One such factor, diet has been shown to modulate miRNA expression in colorectal cancer patients. In this chapter, we will summarize the work demonstrating that miRNAs are novel promising drug targets for cancer chemoprevention and therapy. Improved delivery, increased stability and enhanced regulation of off-target effects will overcome the current challenges of this exciting approach in the field of cancer prevention and therapy.

Significant photocytotoxic effect of an iron(iii) complex of a Schiff base ligand derived from vitamin B6and thiosemicarbazide in visible light

An iron(iii)–Schiff base complex derived from vitamin B₆and thiosemicarbazide is significantly photocytotoxic to HeLa cancer cells in visible light (400 nm–700 nm) but non-toxic in the absence of light.