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Maity J, Majumder S, Pal R, Saha B, Mukhopadhyay PK. Ascorbic acid modulates immune responses through Jumonji-C domain containing histone demethylases and Ten eleven translocation (TET) methylcytosine dioxygenase. Bioessays 2023; 45:e2300035. [PMID: 37694689 DOI: 10.1002/bies.202300035] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 08/29/2023] [Accepted: 08/31/2023] [Indexed: 09/12/2023]
Abstract
Ascorbic acid is a redox regulator in many physiological processes. Besides its antioxidant activity, many intriguing functions of ascorbic acid in the expression of immunoregulatory genes have been suggested. Ascorbic acid acts as a co-factor for the Fe+2 -containing α-ketoglutarate-dependent Jumonji-C domain-containing histone demethylases (JHDM) and Ten eleven translocation (TET) methylcytosine dioxygenasemediated epigenetic modulation. By influencing JHDM and TET, ascorbic acid facilitates the differentiation of double negative (CD4- CD8- ) T cells to double positive (CD4+ CD8+ ) T cells and of T-helper cells to different effector subsets. Ascorbic acid modulates plasma cell differentiation and promotes early differentiation of hematopoietic stem cells (HSCs) to NK cells. These findings indicate that ascorbic acid plays a significant role in regulating both innate and adaptive immune cells, opening up new research areas in Immunonutrition. Being a water-soluble vitamin and a safe micro-nutrient, ascorbic acid can be used as an adjunct therapy for many disorders of the immune system.
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Affiliation(s)
- Jeet Maity
- Department of Life Sciences, Presidency University, Kolkata, India
| | | | - Ranjana Pal
- Department of Life Sciences, Presidency University, Kolkata, India
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2
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Rashid MA, Lin-Moshier Y, Gunaratne GS, Subramanian S, Marchant JS, Subramanian VS. Vitamin C transport in neurons and epithelia is regulated by secretory carrier-associated membrane protein-2 (SCAMP2). Int J Biol Macromol 2023; 230:123205. [PMID: 36632962 DOI: 10.1016/j.ijbiomac.2023.123205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/28/2022] [Accepted: 01/05/2023] [Indexed: 01/11/2023]
Abstract
The human sodium-dependent vitamin C transporter-1 (hSVCT1) is localized at the apical membrane domain of polarized intestinal and renal epithelial cells to mediate ascorbic acid (AA) uptake. Currently, little is known about the array of interacting proteins that aid hSVCT1 trafficking and functional expression at the cell surface. Here we used an affinity tagging ('One-STrEP') and proteomic approach to identify hSVCT1 interacting proteins, which resolved secretory carrier-associated membrane protein-2 (SCAMP2) as a novel accessary protein partner. SCAMP2 was validated as an accessory protein by co-immunoprecipitation with hSVCT1. Co-expression of hSVCT1 and SCAMP2 in HEK-293 cells revealed both proteins co-localized in intracellular structures and at the plasma membrane. Functionally, over-expression of SCAMP2 potentiated 14C-AA uptake, and reciprocally silencing endogenous SCAMP2 decreased 14C-AA uptake. Finally, knockdown of endogenous hSVCT1 or SCAMP2 impaired differentiation of human-induced pluripotent stem cells (hiPSCs) toward a neuronal fate. These results establish SCAMP2 as a novel hSVCT1 accessary protein partner that regulates AA uptake in absorptive epithelia and during neurogenesis.
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Affiliation(s)
- Mohammad A Rashid
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, WI 53226, United States
| | - Yaping Lin-Moshier
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, WI 53226, United States
| | - Gihan S Gunaratne
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, WI 53226, United States
| | - Sreya Subramanian
- Department of Medicine, University of California, Irvine, CA 92697, United States
| | - Jonathan S Marchant
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, WI 53226, United States
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Rosa TG. The Effect of Ascorbic Acid Supplementation on the Time of Healing of Rats Submitted to Neurosurgical Procedures. ARQUIVOS BRASILEIROS DE NEUROCIRURGIA: BRAZILIAN NEUROSURGERY 2022. [DOI: 10.1055/s-0041-1740618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Abstract
Introduction Vitamin C is an essential nutrient for both humans and rats and has been noted for its beneficial properties, among them, healing.
Objective To verify the effect of oral and subcutaneous vitamin C supplementation on the healing time of surgical wounds of rats skulls.
Statistical Methodology Thirty male Wistar rats were divided into 3 groups: 10 from the control group (GI), 10 from the group treated with oral vitamin C (GII), and 10 from the group treated with subcutaneous vitamin C (GIII). Vitamin C was administered to GI and GIII animals from the 3rd to the 7th postoperative day, totaling 10 days of administration at a dose of 100 mg/kg/day. On the 4th day of the study, the rats were submitted to a surgical procedure consisting of a 2-cm incision of the skin of the animals' heads and suturing with single stitches. After a determined period, the rats were killed and submitted to the collection of material for study by the picrosirius red technique for the evaluation of collagen types I and III, the degree of hematoxylin and eosin healing, and the rate of contraction of the wound on subsequent days. The results were described in averages, medians, minimum and maximum values, and standard deviations. For the comparison of the three groups, the analysis of variance with one factor (one-way ANOVA) or Kruskal-Wallis non-parametric test was used. The normality of the variables was evaluated by the Shapiro-Wilk test. Values of p < 0.05 indicated statistical significance. The data were analyzed using the IBM SPSS Statistics for Windows, v.20.0. software. (IBM Corp., Armonk, NY, USA).
Results The amount of collagen type III was higher in the groups that received vitamin C, however, without significant difference (n = 0.292). In relation to the rate of contraction of the surgical wound, it was higher in the groups treated with vitamin C, with a significant difference between groups I and II (p = 0.001), and between groups I and III (p < 0.001). No significant difference was found between the groups that were treated with vitamin C (p = 0.227).
Conclusion Healing was more effective in the groups treated with vitamin C than in the group that did not receive vitamin supplementation. There was no significant difference in healing between the groups receiving oral or subcutaneous vitamin C.
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Teafatiller T, Subramanian S, Marquez FE, Kitazawa M, Subramanian VS. Valproic acid upregulates sodium-dependent vitamin C transporter-2 functional expression in neuronal cells. Life Sci 2022; 308:120944. [PMID: 36096242 DOI: 10.1016/j.lfs.2022.120944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 08/29/2022] [Accepted: 09/06/2022] [Indexed: 01/19/2023]
Abstract
Neuronal uptake of ascorbic acid (AA) in humans occurs via the human sodium-dependent vitamin C transporter-2 (hSVCT2). Recent studies show that a significantly lower level of vitamin C is present in the blood of epileptic patients. Consequently, focused studies investigating the involved molecular mechanisms for hSVCT2 regulation are vital to enhance vitamin C body homeostasis. Currently, little is known about the role of valproic acid (VPA), a drug utilized to treat epilepsy and a class I histone deacetylase inhibitor (HDACi), on AA uptake in neuronal systems. Thus, this study aims to examine the effect of VPA on hSVCT2 functional expression in neuronal cells. VPA treatment upregulated the AA uptake and this increased AA uptake was associated with a significant increase in hSVCT2 expression and SLC23A2 promoter activity in SH-SY5Y cells. Knockdown of HDAC2, a predominant isoform in neuronal systems, significantly increased hSVCT2 functional expression. VPA treatment in mice displayed increased mouse (m)SVCT2 protein, mRNA and heterogenous nuclear RNA (hnRNA) expression in the brain. In addition, Yin Yang-1 (YY1), a transcription factor that drives the SLC23A2 promoter activity, protein and mRNA expression levels were markedly upregulated in VPA-treated SH-SY5Y cells and mice brain. Together, our findings suggest that VPA upregulates the functional expression of SVCT2 via HDAC2 and transcriptional mechanism(s).
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Affiliation(s)
- Trevor Teafatiller
- Department of Medicine, University of California, Irvine, CA 92697, United States of America
| | - Sreya Subramanian
- Department of Medicine, University of California, Irvine, CA 92697, United States of America
| | - Felerico E Marquez
- Department of Medicine, University of California, Irvine, CA 92697, United States of America
| | - Masashi Kitazawa
- Department of Medicine, University of California, Irvine, CA 92697, United States of America; Department of Environmental and Occupational Health, University of California, Irvine, CA 92697, United States of America
| | - Veedamali S Subramanian
- Department of Medicine, University of California, Irvine, CA 92697, United States of America.
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Inference on the structure of gene regulatory networks. J Theor Biol 2022; 539:111055. [PMID: 35150721 DOI: 10.1016/j.jtbi.2022.111055] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 01/29/2022] [Accepted: 02/03/2022] [Indexed: 11/20/2022]
Abstract
In this paper, we conduct theoretical analyses on inferring the structure of gene regulatory networks. Depending on the experimental method and data type, the inference problem is classified into 20 different scenarios. For each scenario, we discuss the problem that with enough data, under what assumptions, what can be inferred about the structure. For scenarios that have been covered in the literature, we provide a brief review. For scenarios that have not been covered in literature, if the structure can be inferred, we propose new mathematical inference methods and evaluate them on simulated data. Otherwise, we prove that the structure cannot be inferred.
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Subramanian VS, Teafatiller T, Vidal J, Gunaratne GS, Rodriguez-Ortiz CJ, Kitazawa M, Marchant JS. Calsyntenin-3 interacts with the sodium-dependent vitamin C transporter-2 to regulate vitamin C uptake. Int J Biol Macromol 2021; 192:1178-1184. [PMID: 34673103 PMCID: PMC9842108 DOI: 10.1016/j.ijbiomac.2021.10.058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 01/19/2023]
Abstract
Ascorbic acid (AA) uptake in neurons occurs via a Na+-dependent carrier-mediated process mediated by the sodium-dependent vitamin C transporter-2 (SVCT2). Relatively little information is available concerning the network of interacting proteins that support human (h)SVCT2 trafficking and cell surface expression in neuronal cells. Here we identified the synaptogenic adhesion protein, calsyntenin-3 (CLSTN3) as an hSVCT2 interacting protein from yeast two-hybrid (Y2H) screening of a human adult brain cDNA library. This interaction was confirmed by co-immunoprecipitation, mammalian two-hybrid (M2H), and co-localization in human cell lines. Co-expression of hCLSTN3 with hSVCT2 in SH-SY5Y cells led to a marked increase in AA uptake. Reciprocally, siRNA targeting hCLSTN3 inhibited AA uptake. In the J20 mouse model of Alzheimer's disease (AD), mouse (m)SVCT2 and mCLSTN3 expression levels in hippocampus were decreased. Similarly, expression levels of hSVCT2 and hCLSTN3 were markedly decreased in hippocampal samples from AD patients. These findings establish CLSTN3 as a novel hSVCT2 interactor in neuronal cells with potential pathophysiological significance.
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Affiliation(s)
- Veedamali S. Subramanian
- Department of Medicine, University of California, Irvine, CA 92697, United States of America,Corresponding author. (V.S. Subramanian)
| | - Trevor Teafatiller
- Department of Medicine, University of California, Irvine, CA 92697, United States of America
| | - Janielle Vidal
- Department of Medicine, University of California, Irvine, CA 92697, United States of America,Department of Environmental and Occupational Health, University of California, Irvine, CA 92697, United States of America
| | - Gihan S. Gunaratne
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, United States of America
| | - Carlos J. Rodriguez-Ortiz
- Department of Medicine, University of California, Irvine, CA 92697, United States of America,Department of Environmental and Occupational Health, University of California, Irvine, CA 92697, United States of America
| | - Masashi Kitazawa
- Department of Medicine, University of California, Irvine, CA 92697, United States of America,Department of Environmental and Occupational Health, University of California, Irvine, CA 92697, United States of America
| | - Jonathan S. Marchant
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, United States of America
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Subramanian VS, Teafatiller T, Moradi H, Marchant JS. Histone deacetylase inhibitors regulate vitamin C transporter functional expression in intestinal epithelial cells. J Nutr Biochem 2021; 98:108838. [PMID: 34403723 DOI: 10.1016/j.jnutbio.2021.108838] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 06/04/2021] [Accepted: 07/08/2021] [Indexed: 02/06/2023]
Abstract
Intestinal absorption of vitamin C in humans is mediated via the sodium-dependent vitamin C transporters (hSVCT1 and hSVCT2). hSVCT1 and hSVCT2 are localized at the apical and basolateral membranes, respectively, of polarized intestinal epithelia. Studies have identified low plasma levels of vitamin C and decreased expression of hSVCT1 in patients with several inflammatory conditions including inflammatory bowel disease (IBD). Investigating the underlying mechanisms responsible for regulating hSVCT1 expression are critical for understanding vitamin C homeostasis, particularly in conditions where suboptimal vitamin C levels detrimentally affect human health. Previous research has shown that hSVCT1 expression is regulated at the transcriptional level, however, little is known about epigenetic regulatory pathways that modulate hSVCT1 expression in the intestine. In this study, we found that hSVCT1 expression and function were significantly decreased in intestinal epithelial cells by the histone deacetylase inhibitors (HDACi), valproic acid (VPA), and sodium butyrate (NaB). Further, expression of transcription factor HNF1α, which is critical for SLC23A1 promoter activity, was significantly down regulated in VPA-treated cells. Chromatin immunoprecipitation (ChIP) assays showed significantly increased enrichment of tetra-acetylated histone H3 and H4 within the SLC23A1 promoter following VPA treatment. In addition, knockdown of HDAC isoforms two, and three significantly decreased hSVCT1 functional expression. Following VPA administration to mice, functional expression of SVCT1 in the jejunum was significantly decreased. Collectively, these in vitro and in vivo studies demonstrate epigenetic regulation of SVCT1 expression in intestinal epithelia partly mediated through HDAC isoforms two and three.
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Affiliation(s)
| | - Trevor Teafatiller
- Department of Medicine, University of California, Irvine, California, USA
| | - Hamid Moradi
- Department of Medicine, University of California, Irvine, California, USA; Tibor Rubin VA Medical Center, Long Beach, California, USA
| | - Jonathan S Marchant
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Effect of Lipopolysaccharide and TNF α on Neuronal Ascorbic Acid Uptake. Mediators Inflamm 2021; 2021:4157132. [PMID: 34285658 PMCID: PMC8275400 DOI: 10.1155/2021/4157132] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 06/22/2021] [Indexed: 01/14/2023] Open
Abstract
Vitamin C (ascorbic acid: AA) uptake in neurons occurs via the sodium-dependent vitamin C transporter-2 (SVCT2), which is highly expressed in the central nervous system (CNS). During chronic neuroinflammation or infection, CNS levels of lipopolysaccharide (LPS) and LPS-induced tumor necrosis factor-α (TNFα) are increased. Elevated levels of LPS and TNFα have been associated with neurodegenerative diseases together with reduced levels of AA. However, little is known about the impacts of LPS and TNFα on neuronal AA uptake. The objective of this study was to examine the effect of LPS and TNFα on SVCT2 expression and function using in vitro and in vivo approaches. Treatment of SH-SY5Y cells with either LPS or TNFα inhibited AA uptake. This reduced uptake was associated with a significant decrease in SVCT2 protein and mRNA levels. In vivo exposure to LPS or TNFα also decreased SVCT2 protein and mRNA levels in mouse brains. Both LPS and TNFα decreased SLC23A2 promoter activity. Further, the inhibitory effect of LPS on a minimal SLC23A2 promoter was attenuated when either the binding site for the transcription factor Sp1 was mutated or cells were treated with the NF-κB inhibitor, celastrol. We conclude that inflammatory signals suppress AA uptake by impairing SLC23A2 transcription through opposing regulation of Sp1 and NF-κB factors.
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Enteropathogenic Escherichia coli Infection Inhibits Intestinal Ascorbic Acid Uptake via Dysregulation of Its Transporter Expression. Dig Dis Sci 2021; 66:2250-2260. [PMID: 32556816 PMCID: PMC7744340 DOI: 10.1007/s10620-020-06389-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 06/03/2020] [Indexed: 02/04/2023]
Abstract
BACKGROUND Enteropathogenic Escherichia coli (EPEC) infection causes prolonged, watery diarrhea leading to morbidity and mortality. Although EPEC infection impacts nutrient transporter function and expression in intestinal epithelial cells, the effects of EPEC infection on intestinal absorption of ascorbic acid (AA) have not yet been investigated. AIMS To investigate the effect of EPEC infection on intestinal AA uptake process and expression of both AA transporters. METHODS We used two experimental models: human-derived intestinal epithelial Caco-2 cells and mice. 14C-AA uptake assay, Western blot, RT-qPCR, and promoter assay were performed. RESULTS EPEC (WT) as well as ΔespF and ΔespG/G2 mutant-infected Caco-2 cells showed markedly inhibited AA uptake, while other mutants (ΔescN, ΔespA, ΔespB, and ΔespD) did not affect AA uptake. Infection also reduced protein and mRNA expression levels for both hSVCT1 and hSVCT2. EPEC-infected mice showed marked inhibitory effect on AA uptake and decreased protein and mRNA expression levels for both mSVCT1 and mSVCT2 in jejunum and colon. MicroRNA regulators of SVCT1 and SVCT2 (miR103a, miR141, and miR200a) were upregulated significantly upon EPEC infection in both Caco-2 and mouse jejunum and colon. In addition, expression of the accessory protein glyoxalate reductase/hydroxypyruvate reductase (GRHPR), which regulates SVCT1 function, was markedly decreased by EPEC infection in both models. CONCLUSIONS These findings suggest that EPEC infection causes inhibition in AA uptake through a multifactorial dysregulation of SVCT1 and SVCT2 expression in intestinal epithelial cells.
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Teafatiller T, Heskett CW, Agrawal A, Marchant JS, Baulch JE, Acharya MM, Subramanian VS. Upregulation of Vitamin C Transporter Functional Expression in 5xFAD Mouse Intestine. Nutrients 2021; 13:nu13020617. [PMID: 33672967 PMCID: PMC7918291 DOI: 10.3390/nu13020617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 02/05/2021] [Accepted: 02/11/2021] [Indexed: 01/14/2023] Open
Abstract
The process of obtaining ascorbic acid (AA) via intestinal absorption and blood circulation is carrier-mediated utilizing the AA transporters SVCT1 and SVCT2, which are expressed in the intestine and brain (SVCT2 in abundance). AA concentration is decreased in Alzheimer’s disease (AD), but information regarding the status of intestinal AA uptake in the AD is still lacking. We aimed here to understand how AA homeostasis is modulated in a transgenic mouse model (5xFAD) of AD. AA levels in serum from 5xFAD mice were markedly lower than controls. Expression of oxidative stress response genes (glutathione peroxidase 1 (GPX1) and superoxide dismutase 1 (SOD1)) were significantly increased in AD mice jejunum, and this increase was mitigated by AA supplementation. Uptake of AA in the jejunum was upregulated. This increased AA transport was caused by a marked increase in SVCT1 and SVCT2 protein, mRNA, and heterogeneous nuclear RNA (hnRNA) expression. A significant increase in the expression of HNF1α and specific protein 1 (Sp1), which drive SLC23A1 and SLC23A2 promoter activity, respectively, was observed. Expression of hSVCT interacting proteins GRHPR and CLSTN3 were also increased. SVCT2 protein and mRNA expression in the hippocampus of 5xFAD mice was not altered. Together, these investigations reveal adaptive up-regulation of intestinal AA uptake in the 5xFAD mouse model.
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Affiliation(s)
- Trevor Teafatiller
- Department of Medicine, University of California, Irvine, CA 92697, USA; (T.T.); (C.W.H.); (A.A.)
| | - Christopher W. Heskett
- Department of Medicine, University of California, Irvine, CA 92697, USA; (T.T.); (C.W.H.); (A.A.)
| | - Anshu Agrawal
- Department of Medicine, University of California, Irvine, CA 92697, USA; (T.T.); (C.W.H.); (A.A.)
| | - Jonathan S. Marchant
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA;
| | - Janet E. Baulch
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (J.E.B.); (M.M.A.)
| | - Munjal M. Acharya
- Department of Radiation Oncology, University of California, Irvine, CA 92697, USA; (J.E.B.); (M.M.A.)
| | - Veedamali S. Subramanian
- Department of Medicine, University of California, Irvine, CA 92697, USA; (T.T.); (C.W.H.); (A.A.)
- Correspondence: ; Tel.: +1-949-824-3084
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Enhanced Anticancer Effect of Adding Magnesium to Vitamin C Therapy: Inhibition of Hormetic Response by SVCT-2 Activation. Transl Oncol 2019; 13:401-409. [PMID: 31901552 PMCID: PMC6940627 DOI: 10.1016/j.tranon.2019.10.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 10/24/2019] [Accepted: 10/29/2019] [Indexed: 12/17/2022] Open
Abstract
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 Vmax 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 Vmax 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.
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Srinivasan P, Ramesh V, Wu J, Heskett C, Chu BD, Said HM. Pyridoxine and pancreatic acinar cells: transport physiology and effect on gene expression profile. Am J Physiol Cell Physiol 2019; 317:C1107-C1114. [PMID: 31483702 DOI: 10.1152/ajpcell.00225.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Pyridoxine (vitamin B6), an essential micronutrient for normal cell physiology, plays an important role in the function of the exocrine pancreas. Pancreatic acinar cells (PACs) obtain vitamin B6 from circulation, but little is known about the mechanism involved in the uptake process; limited information also exists on the effect of pyridoxine availability on the gene expression profile in these cells. We addressed both these issues in the current investigation using mouse-derived pancreatic acinar 266-6 cells (PAC 266-6) and human primary PACs (hPACs; obtained from organ donors), together with appropriate physiological and molecular (RNA-Seq) approaches. The results showed [3H]pyridoxine uptake to be 1) pH and temperature (but not Na+) dependent, 2) saturable as a function of concentration, 3) cis-inhibited by unlabeled pyridoxine and its close structural analogs, 4) trans-stimulated by unlabeled pyridoxine, 5) regulated by an intracellular Ca2+/calmodulin-mediated pathway, 6) adaptively-regulated by extracellular substrate (pyridoxine) availability, and 7) negatively impacted by exposure to cigarette smoke extract. Vitamin B6 availability was found (by means of RNA-Seq) to significantly (FDR < 0.05) modulate the expression profile of many genes in PAC 266-6 cells (including those that are relevant to pancreatic health and development). These studies demonstrate, for the first time, the involvement of a regulatable and specific carrier-mediated mechanism for pyridoxine uptake by PACs; the results also show that pyridoxine availability exerts profound effects on the gene expression profile in mammalian PACs.
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Affiliation(s)
- Padmanabhan Srinivasan
- Department of Medicine, University of California, Irvine, California.,Department of Physiology/Biophysics, University of California, Irvine, California.,Department of Medical Research, Veterans Affairs Medical Center, Long Beach, California
| | - Vignesh Ramesh
- Department of Medicine, University of California, Irvine, California.,Department of Physiology/Biophysics, University of California, Irvine, California.,Department of Medical Research, Veterans Affairs Medical Center, Long Beach, California
| | - Jie Wu
- Department of Biological Chemistry, University of California, Irvine, California
| | - Christopher Heskett
- Department of Medicine, University of California, Irvine, California.,Department of Physiology/Biophysics, University of California, Irvine, California.,Department of Medical Research, Veterans Affairs Medical Center, Long Beach, California
| | - Brian D Chu
- Department of Medicine, University of California, Irvine, California.,Department of Physiology/Biophysics, University of California, Irvine, California.,Department of Medical Research, Veterans Affairs Medical Center, Long Beach, California
| | - Hamid M Said
- Department of Medicine, University of California, Irvine, California.,Department of Physiology/Biophysics, University of California, Irvine, California.,Department of Medical Research, Veterans Affairs Medical Center, Long Beach, California
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13
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Subramanian VS, Sabui S, Marchant JS, Said HM. MicroRNA-103a regulates sodium-dependent vitamin C transporter-1 expression in intestinal epithelial cells. J Nutr Biochem 2019; 65:46-53. [PMID: 30616065 PMCID: PMC6420349 DOI: 10.1016/j.jnutbio.2018.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 11/04/2018] [Accepted: 12/03/2018] [Indexed: 12/31/2022]
Abstract
Intestinal absorption of ascorbic acid (AA) occurs via a Na+-dependent carrier-mediated process facilitated through the human sodium-dependent vitamin C transporters-1 &-2 (hSVCT1 and hSVCT2). Many studies have shown that hSVCT1 (product of the SLC23A1 gene) is expressed on the apical membrane of polarized enterocytes where it mediates AA absorption. hSVCT1 expression levels are therefore an important determinant of physiological vitamin C homeostasis. However, little is known about posttranscriptional mechanisms that regulate hSVCT1 expression in intestinal epithelia. In this study, we investigated regulation of hSVCT1 by microRNA (miRNA). A pmirGLO-SLC23A1-3'-UTR construct transfected into human intestinal cell lines (Caco-2 and NCM460 cells) showed markedly reduced luciferase activity. Bioinformatic analysis of the SLC23A1-3'-UTR predicted five miRNA binding sites (miR-103a, miR-107, miR-328, miR-384, and miR-499-5p) in the 3'-UTR. Expression of mature miR-103a was markedly higher compared to the other four putative miRNA regulators in both intestinal cell lines and mouse jejunal mucosa. Addition of a miR-103a mimic, but not a miR-103a mutant construct, markedly reduced the luminescence of the pmirGLO-SLC23A1-3'-UTR reporter. Reciprocally, addition of a miR-103a inhibitor significantly increased luciferase reporter activity. Addition of the miR-103a mimic led to a significant inhibition in AA uptake, associated with decreased hSVCT1 mRNA and protein expression in Caco-2 cells. In contrast, the miR-103a inhibitor increased AA uptake, associated with increased levels of hSVCT1 mRNA and protein. These findings provide the first evidence for posttranscriptional regulation of hSVCT1 by miRNA in intestinal epithelial cells.
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Affiliation(s)
- Veedamali S Subramanian
- Department of Medicine, University of California, Irvine, CA 92697; Department of Physiology/Biophysics, University of California, Irvine, CA 92697; VA Medical Center, Long Beach, CA 90822.
| | - Subrata Sabui
- Department of Medicine, University of California, Irvine, CA 92697; Department of Physiology/Biophysics, University of California, Irvine, CA 92697; VA Medical Center, Long Beach, CA 90822
| | - Jonathan S Marchant
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, WI 53226
| | - Hamid M Said
- Department of Medicine, University of California, Irvine, CA 92697; Department of Physiology/Biophysics, University of California, Irvine, CA 92697; VA Medical Center, Long Beach, CA 90822
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Subramenium GA, Sabui S, Marchant JS, Said HM, Subramanian VS. Enterotoxigenic Escherichia coli heat labile enterotoxin inhibits intestinal ascorbic acid uptake via a cAMP-dependent NF-κB-mediated pathway. Am J Physiol Gastrointest Liver Physiol 2019; 316:G55-G63. [PMID: 30285481 PMCID: PMC6383388 DOI: 10.1152/ajpgi.00259.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Vitamin C is an antioxidant and acts as a cofactor for many enzymatic reactions. Humans obtain vitamin C from dietary sources via intestinal absorption, a process that involves the sodium-dependent vitamin C transporters-1 and -2 (SVCT1 and SVCT2). Enterotoxigenic Escherichia coli (ETEC) infection impacts intestinal absorption/secretory functions, but nothing is known about its effect on ascorbic acid (AA) uptake. Here we demonstrate that infection of Caco-2 cells with ETEC led to a significant inhibition in intestinal AA uptake. This inhibition was associated with a marked reduction in hSVCT1 and hSVCT2 protein, mRNA, and heterogeneous nuclear RNA (hnRNA) expression levels as well as significant inhibition in the activity of both the SLC23A1 and SLC23A2 promoters. Similarly, exposure of mice to ETEC led to a significant inhibition in intestinal AA uptake and reduction in mSVCT1 and mSVCT2 protein, mRNA, and hnRNA expression levels. Inhibition was caused by the action of heat labile enterotoxin (LT), since infecting Caco-2 cells with LT-deficient ETEC (ΔLT) failed to impact AA uptake. Because LT activates adenylate cyclase, we also examined the effect of dibutyryl-cAMP in AA uptake by Caco-2 cells and observed a significant inhibition. Furthermore, treating the cells with celastrol, a specific NF-κB inhibitor, significantly blocked the inhibition of AA uptake caused by ETEC infection. Together, these data demonstrate that ETEC infection impairs intestinal AA uptake through a cAMP-dependent NF-κB-mediated pathway that regulates both SLC23A1 and SLC23A2 transcription. NEW & NOTEWORTHY Our findings demonstrate that heat-labile enterotoxin produced by enterotoxigenic Escherichia coli inhibits AA uptake in intestinal epithelial cells and mouse intestine. This effect is mediated through transcriptional repression of SLC23A1 (SVCT1) and SLC23A2 (SVCT2) via a cAMP-dependent NF-κB signaling pathway.
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Affiliation(s)
- Ganapathy A. Subramenium
- 1Department of Medicine, University of California, Irvine, California,3Department of Veterans Affairs Medical Center, Long Beach, California
| | - Subrata Sabui
- 1Department of Medicine, University of California, Irvine, California,2Department of Physiology and Biophysics, University of California, Irvine, California,3Department of Veterans Affairs Medical Center, Long Beach, California
| | - Jonathan S. Marchant
- 4Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Hamid M. Said
- 1Department of Medicine, University of California, Irvine, California,2Department of Physiology and Biophysics, University of California, Irvine, California,3Department of Veterans Affairs Medical Center, Long Beach, California
| | - Veedamali S. Subramanian
- 1Department of Medicine, University of California, Irvine, California,2Department of Physiology and Biophysics, University of California, Irvine, California,3Department of Veterans Affairs Medical Center, Long Beach, California
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Stsiapura VI, Bederman I, Stepuro II, Morozkina TS, Lewis SJ, Smith L, Gaston B, Marozkina N. S-Nitrosoglutathione formation at gastric pH is augmented by ascorbic acid and by the antioxidant vitamin complex, Resiston. PHARMACEUTICAL BIOLOGY 2018; 56:86-93. [PMID: 29298528 PMCID: PMC6130629 DOI: 10.1080/13880209.2017.1421674] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
CONTEXT Exogenous nitrogen oxides must be made bioavailable to sustain normal physiology because nitric oxide synthase (NOS) deficient mice are viable. In the stomach, S-nitrosoglutathione (GSNO) is formed from ingested nitrite and high levels of airway glutathione (GSH) that are cleared and swallowed. However, gastric GSNO may be broken down by nutrients like ascorbic acid (AA) before it is absorbed. OBJECTIVE To study the effect of AA on GSNO formation and stability. MATERIALS AND METHODS GSH and nitrite were reacted with or without 5 mM AA or Resiston (5 mM AA with retinoic acid and α-tocopherol). GSNO was measured by reduction/chemiluminescence and HPLC. AA and reduced thiols were measured colorimetrically. O-Nitrosoascorbate and AA were measured by gas chromatography-mass spectrometry (GC-MS). RESULTS GSNO was formed in saline and gastric samples (pH ∼4.5) from physiological levels of GSH and nitrite. Neither AA nor Resiston decreased [GSNO] at pH >3; rather, they increased [GSNO] (0.12 ± 0.19 μM without AA; 0.42 ± 0.35 μM with AA; and 0.43 ± 0.23 μM with Resiston; n = 4 each; p ≤ 0.05). However, AA compounds decreased [GSNO] at lower pH and with incubation >1 h. Mechanistically, AA, but not dehydroascorbate, increased GSNO formation; and the O-nitrosoascorbate intermediate was formed. CONCLUSIONS AA, with or without other antioxidants, did not deplete GSNO formed from physiological levels of GSH and nitrite at pH >3. In fact, it favoured GSNO formation, likely through O-nitrosoascorbate. Gastric GSNO could be a NOS-independent source of bioavailable nitrogen oxides.
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Affiliation(s)
| | - Ilya Bederman
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Ivan I. Stepuro
- Department of Biochemistry, Yanka Kupala State University, Grodno, Belarus
| | | | - Stephen J. Lewis
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Laura Smith
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Benjamin Gaston
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
- Divisions of Pediatrics Pulmonology, Allergy, Immunology and Sleep Medicine and Gastroenterology and Nutrition, Rainbow Babies and Children’s Hospital, Cleveland, OH, USA
| | - Nadzeya Marozkina
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
- CONTACT Nadzeya MarozkinaCase Western Reserve University, 10900 Euclid Ave, BRB 722, Cleveland, OH44106, USA
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Subramanian VS, Sabui S, Subramenium GA, Marchant JS, Said HM. Tumor necrosis factor alpha reduces intestinal vitamin C uptake: a role for NF-κB-mediated signaling. Am J Physiol Gastrointest Liver Physiol 2018; 315:G241-G248. [PMID: 29631379 PMCID: PMC6139644 DOI: 10.1152/ajpgi.00071.2018] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Sodium-dependent vitamin C transporter-1 (SVCT-1) is the major transporter mediating intestinal vitamin C uptake. Intestinal inflammation and prolonged infection are associated with increased serum and intestinal mucosa levels of tumor necrosis factor-α (TNF-α), which also exerts profound effects on the intestinal absorption process. Elevated levels of TNF-α have been linked to the pathogenesis of inflammatory bowel disease (IBD) and malabsorption of nutrients, and patients with this condition have low levels of vitamin C. To date, little is known about the effect of TNF-α on intestinal absorption of vitamin C. We studied the impact of TNF-α on ascorbic acid (AA) transport using a variety of intestinal preparations. The expression level of human SVCT-1 mRNA is significantly lower in patients with IBD. TNF-α treated Caco-2 cells and mice showed a significant inhibition of intestinal 14C-AA uptake. This inhibition was associated with significant decreases in SVCT-1 protein, mRNA, and heterogeneous nuclear RNA levels in TNF-α treated Caco-2 cells, mouse jejunum, and enteroids. Also, TNF-α caused a significant inhibition in the SLC23A1 promoter activity. Furthermore, treatment of Caco-2 cells with celastrol (NF-κB inhibitor) blocked the inhibitory effect caused by TNF-α on AA uptake, SVCT-1 protein, and mRNA expression, as well as the activity of SLC23A1 promoter. Treatment of TNF-α also led to a significant decrease in the expression of hepatocyte nuclear factor-1-α, which drives the basal activity of SLC23A1 promoter, and this effect was reversed by celastrol. Together, these findings show that TNF-α inhibits intestinal AA uptake, and this effect is mediated, at least in part, at the level of transcription of the SLC23A1 gene via the NF-κB pathway. NEW & NOTEWORTHY Our findings show that tumor necrosis factor-α inhibits intestinal ascorbic acid uptake in both in vitro and in vivo systems, and this inhibitory effect is mediated, at least in part, at the level of transcription of the SLC23A1 (sodium-dependent vitamin C transporter-1) gene via the NF-κB pathway.
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Affiliation(s)
- Veedamali S. Subramanian
- 1Department of Medicine, University of California, Irvine, California,2Department of Physiology and Biophysics, University of California, Irvine, California,3Department of Veterans Affairs Medical Center, Long Beach, California
| | - Subrata Sabui
- 1Department of Medicine, University of California, Irvine, California,2Department of Physiology and Biophysics, University of California, Irvine, California,3Department of Veterans Affairs Medical Center, Long Beach, California
| | - Ganapathy A. Subramenium
- 1Department of Medicine, University of California, Irvine, California,2Department of Physiology and Biophysics, University of California, Irvine, California,3Department of Veterans Affairs Medical Center, Long Beach, California
| | - Jonathan S. Marchant
- 4Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Hamid M. Said
- 1Department of Medicine, University of California, Irvine, California,2Department of Physiology and Biophysics, University of California, Irvine, California,3Department of Veterans Affairs Medical Center, Long Beach, California
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Differentiation of Promonocytic U937 Cells to Monocytes Is Associated with Reduced Mitochondrial Transport of Ascorbic Acid. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:4194502. [PMID: 29576847 PMCID: PMC5822789 DOI: 10.1155/2018/4194502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 11/30/2017] [Accepted: 12/26/2017] [Indexed: 12/20/2022]
Abstract
Growth of promonocytic U937 cells in the presence of DMSO promotes their differentiation to monocytes. After 4 days of culture in differentiating medium, these cells ceased to proliferate, displayed downregulated ryanodine receptor expression, and responded to specific stimuli with enhanced NADPH-oxidase-derived superoxide formation or cytosolic phospholipase A2-dependent arachidonic acid release. We found that the 4-day differentiation process is also associated with downregulated SVCT2 mRNA expression, in the absence of apparent changes in SVCT2 protein expression and transport rate of ascorbic acid (AA). Interestingly, under the same conditions, these cells accumulated lower amounts of the vitamin in their mitochondria, with an ensuing reduced response to external stimuli sensitive to the mitochondrial fraction of AA. Further analyses demonstrated an unexpected increase in mitochondrial SVCT2 protein expression, however, associated with reduced SVCT2-dependent AA uptake in isolated mitochondria. A decrease in the transporter Vmax, with no change in affinity, was found to account for this response. Differentiation of promonocytic cells to monocytes is therefore characterized by decreased SVCT2 mRNA expression that, even prior to the onset of SVCT2 protein downregulation or apparent changes in plasma membrane transport activity, impacts on the mitochondrial accumulation of the vitamin through a decreased Vmax of the transporter.
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Vitamin C preferentially kills cancer stem cells in hepatocellular carcinoma via SVCT-2. NPJ Precis Oncol 2018; 2:1. [PMID: 29872720 PMCID: PMC5871898 DOI: 10.1038/s41698-017-0044-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 11/07/2017] [Accepted: 11/16/2017] [Indexed: 12/24/2022] Open
Abstract
Vitamin C (L-ascorbic acid, ascorbate, VC) is a potential chemotherapeutic agent for cancer patients. However, the anti-tumor effects of pharmacologic VC on hepatocellular carcinoma (HCC) and liver cancer stem cells (CSCs) remain to be fully elucidated. Panels of human HCC cell lines as well as HCC patient-derived xenograft (PDX) models were employed to investigate the anti-tumor effects of pharmacologic VC. The use of VC and the risk of HCC recurrence were examined retrospectively in 613 HCC patients who received curative liver resection as their initial treatment. In vitro and in vivo experiments further demonstrated that clinically achievable concentrations of VC induced cell death in liver cancer cells and the response to VC was correlated with sodium-dependent vitamin C transporter 2 (SVCT-2) expressions. Mechanistically, VC uptake via SVCT-2 increased intracellular ROS, and subsequently caused DNA damage and ATP depletion, leading to cell cycle arrest and apoptosis. Most importantly, SVCT-2 was highly expressed in liver CSCs, which promoted their self-renewal and rendered them more sensitive to VC. In HCC cell lines xenograft models, as well as in PDX models, VC dramatically impaired tumor growth and eradicated liver CSCs. Finally, retrospective cohort study showed that intravenous VC use was linked to improved disease-free survival (DFS) in HCC patients (adjusted HR = 0.622, 95% CI 0.487 to 0.795, p < 0.001). Our data highlight that pharmacologic VC can effectively kill liver cancer cells and preferentially eradicate liver CSCs, which provide further evidence supporting VC as a novel therapeutic strategy for HCC treatment. Pharmacologic doses of vitamin C preferentially eradicate liver cancer stem cells and are associated with improved outcomes in patients. A team led by Hong-Yang Wang and Wen Yang from the Second Military Medical University in Shanghai, China, showed that clinically achievable concentrations of vitamin C effectively killed liver cancer cells and preferentially eradicated cancer stem cells in culture and in mouse transplant models. Cells with higher expression levels of a vitamin C transporter protein were more susceptible to the treatment, which explains why cancer stem cells, which highly express this transportor and use it for their own self-renewal, were especially sensitive to take in vitamin C, which led to a cascade that resulted in DNA damage, energy depletion, and ultimately cell death. A retrospective analysis of 613 patients with liver cancer showed that those who received intravenous vitamin C lived longer without disease relapse.
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Subramanian VS, Sabui S, Moradi H, Marchant JS, Said HM. Inhibition of intestinal ascorbic acid uptake by lipopolysaccharide is mediated via transcriptional mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:556-565. [PMID: 29030247 DOI: 10.1016/j.bbamem.2017.10.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/14/2017] [Accepted: 10/08/2017] [Indexed: 12/28/2022]
Abstract
Ascorbic acid (AA) accumulation in intestinal epithelial cells is an active transport process mainly mediated by two sodium-dependent vitamin C transporters (SVCT-1 and SVCT-2). To date, little is known about the effect of gut microbiota generated lipopolysaccharide (LPS) on intestinal absorption of water-soluble vitamins. Therefore, the objective of this study was to investigate the effects of bacterially-derived LPS on AA homeostasis in enterocytes using Caco-2 cells, mouse intestine and intestinal enteroids models. Pre-treating Caco-2 cells and mice with LPS led to a significant decrease in carrier-mediated AA uptake. This inhibition was associated with a significant reduction in SVCT-1 and SVCT-2 protein, mRNA, and hnRNA expression. Furthermore, pre-treating enteroids with LPS also led to a marked decrease in SVCT-1 and SVCT-2 protein and mRNA expression. Inhibition of SVCT-1 and SVCT-2 occurred at least in part at the transcriptional level as promoter activity of SLC23A1 and SLC23A2 was attenuated following LPS treatment. Subsequently, we examined the protein and mRNA expression levels of HNF1α and Sp1 transcription factors, which are needed for basal SLC23A1 and SLC23A2 promoter activity, and found that they were significantly decreased in the LPS treated Caco-2 cells and mouse jejunum; this was reflected on level of the observed reduction in the interaction of these transcription factors with their respective promoters in Caco-2 cells treated with LPS. Our findings indicate that LPS inhibits intestinal carrier- mediated AA uptake by down regulating the expression of both vitamin C transporters and transcriptional regulation of SLC23A1 and SLC23A2 genes.
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Affiliation(s)
- Veedamali S Subramanian
- Departments of Medicine, Physiology and Biophysics, University of California, Irvine, CA 92697, United States; Department of Veterans Affairs Medical Center, Long Beach, CA 90822, United States.
| | - Subrata Sabui
- Departments of Medicine, Physiology and Biophysics, University of California, Irvine, CA 92697, United States; Department of Veterans Affairs Medical Center, Long Beach, CA 90822, United States
| | - Hamid Moradi
- Departments of Medicine, Physiology and Biophysics, University of California, Irvine, CA 92697, United States; Department of Veterans Affairs Medical Center, Long Beach, CA 90822, United States
| | - Jonathan S Marchant
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, United States
| | - Hamid M Said
- Departments of Medicine, Physiology and Biophysics, University of California, Irvine, CA 92697, United States; Department of Veterans Affairs Medical Center, Long Beach, CA 90822, United States
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Karim MR, Kadowaki M. Effect and proposed mechanism of vitamin C modulating amino acid regulation of autophagic proteolysis. Biochimie 2017; 142:51-62. [PMID: 28804003 DOI: 10.1016/j.biochi.2017.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 08/09/2017] [Indexed: 10/19/2022]
Abstract
Autophagy is an intracellular bulk degradation process, induced under nutrient starvation. Failure of autophagy has been recognized as a contributor to aging and multiple age related neurodegenerative diseases. Improving autophagy is a beneficial anti-aging strategy, however very few physiological regulators have been identified. Here, we demonstrate that vitamin C is a nutritional stimulator of autophagy. Supplementation of fresh hepatocytes with vitamin C increased autophagic proteolysis significantly in the presence of amino acids in a dose- and time-dependent manner, although no effect was observed in the absence of amino acids. In addition, inhibitor studies with 3-methyladenine, chloroquine, leupeptin and β-lactone confirmed that vitamin C is active through the lysosomal autophagy and not the proteasome pathway. Furthermore, the autophagy marker LC3 protein was significantly increased by vitamin C, suggesting its possible site of action is at the formation step. Both the reduced (ascorbic acid, AsA) and oxidized form (dehydroascorbic acid, DHA) of vitamin C exhibited equal enhancing effect, indicating that the effect does not depend on the anti-oxidation functionality of vitamin C. To understand the mechanism, we established that the effective dose (50 μM) was 15× lower than the intracellular content suggesting these would be only a minor influx from the extracellular pool. Moreover, transporter inhibitor studies in an AsA deficient ODS model rat revealed more accurately that the enhancing effect on autophagic proteolysis still existed, even though the intracellular influx of AsA was blocked. Taken together, these results provide evidence that vitamin C can potentially act through extracellular signaling.
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Affiliation(s)
- Md Razaul Karim
- Department of Applied Biological Chemistry, Graduate School of Science and Technology, Niigata University, Nishi-Ku, Niigata, 950-2181, Japan.
| | - Motoni Kadowaki
- Department of Applied Biological Chemistry, Graduate School of Science and Technology, Niigata University, Nishi-Ku, Niigata, 950-2181, Japan; Center for Transdisciplinary Research, Niigata University, Nishi-Ku, Niigata, 950-2181, Japan
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Maldonado M, Inostroza E, Peña E, Moncada N, Mardones L, Medina JL, Muñoz A, Gatica M, Villagrán M, Escobar E, Mendoza P, Roa FJ, González M, Guzmán P, Gutiérrez-Castro FA, Sweet K, Muñoz-Montesino C, Vera JC, Rivas CI. Sustained blockade of ascorbic acid transport associated with marked SVCT1 loss in rat hepatocytes containing increased ascorbic acid levels after partial hepatectomy. Free Radic Biol Med 2017; 108:655-667. [PMID: 28419867 DOI: 10.1016/j.freeradbiomed.2017.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 03/20/2017] [Accepted: 04/06/2017] [Indexed: 11/22/2022]
Abstract
The liver has an extraordinary regenerative capacity in response to partial hepatectomy (PHx), which develops with neither tissue inflammation response nor alterations in the whole organism. This process is highly coordinated and it has been associated with changes in glutathione (GSH) metabolism. However, there are no reports indicating ascorbic acid (AA) levels after partial hepatectomy. AA and GSH act integrally as an antioxidant system that protects cells and tissues from oxidative damage and imbalance observed in a variety of diseases that affect the liver. Although rat hepatocytes are able to synthesize AA and GSH, which are the providers of AA for the whole organism, they also acquire AA from extracellular sources through the sodium-coupled ascorbic acid transporter-1 (SVCT1). Here, we show that hepatocytes from rat livers subjected to PHx increase their GSH and AA levels from 1 to 7 days post hepatectomy, whose peaks precede the peak in cell proliferation observed at 3 days post-hepatectomy. The increase in both antioxidants was associated with higher expression of the enzymes involved in their synthesis, such as the modifier subunit of enzyme glutamine cysteine ligase (GCLM), glutathione synthetase (GS), gulonolactonase (GLN) and gulonolactone oxidase (GULO). Importantly, rat hepatocytes, that normally exhibit kinetic evidence indicating only SVCT1-mediated transport of AA, lost more than 90% of their capacity to transport it at day 1 after PHx without evidence of recovery at day 7. This observation was in agreement with loss of SVCT1 protein expression, which was undetectable in hepatocytes as early as 2h after PHx, with partial recovery at day 7, when the regenerated liver weight returns to normal. We conclude that after PHx, rat hepatocytes enhance their antioxidant capacity by increasing GSH and AA levels prior to the proliferative peak. GSH and AA are increased by de novo synthesis, however paradoxically hepatocytes from rat subjected to PHx also suppress their capacity to acquire AA from extracellular sources through SVCT1.
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Affiliation(s)
- Mafalda Maldonado
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile.
| | - Eveling Inostroza
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Eduardo Peña
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Natacha Moncada
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Lorena Mardones
- Departamento de Ciencias Básicas, Facultad de Medicina, Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción, Chile
| | - José Luis Medina
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Alejandra Muñoz
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Marcell Gatica
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Marcelo Villagrán
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile; Departamento de Ciencias Básicas, Facultad de Medicina, Universidad Católica de la Santísima Concepción, Alonso de Ribera 2850, Concepción, Chile
| | - Elizabeth Escobar
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Pamela Mendoza
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Francisco J Roa
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Mauricio González
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Paula Guzmán
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | | | - Karen Sweet
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Carola Muñoz-Montesino
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Juan Carlos Vera
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Coralia I Rivas
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile.
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SVCT-2 determines the sensitivity to ascorbate-induced cell death in cholangiocarcinoma cell lines and patient derived xenografts. Cancer Lett 2017; 398:1-11. [PMID: 28385602 DOI: 10.1016/j.canlet.2017.03.039] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 12/21/2022]
Abstract
Cholangiocarcinoma (CC) is a devastating malignancy with late diagnosis and poor response to conventional chemotherapy. Recent studies have revealed anti-cancer effect of vitamin C (l-ascorbic acid, ascorbate) in several types of cancer. However, the effect of l-ascorbic acid (AA) in CC remains elusive. Herein, we demonstrated that AA induced cytotoxicity in CC cells by generating intracellular reactive oxygen species (ROS), and subsequently DNA damage, ATP depletion, mTOR pathway inhibition. Moreover, AA worked synergistically with chemotherapeutic agent cisplatin to impair CC cells growth both in vitro and in vivo. Intriguingly, sodium-dependent vitamin C transporter 2 (SVCT-2) expression was inversely correlated with IC50 values of AA. Knockdown of SVCT-2 dramatically alleviated DNA damage, ATP depletion, and inhibition of mTOR pathway induced by AA. Furthermore, SVCT-2 knockdown endowed CC cells with the resistance to AA treatment. Finally, the inhibitory effects of AA were further confirmed in patient-derived CC xenograft models. Thus, our results unravel therapeutic potential of AA alone or in combination with cisplatin for CC. SVCT2 expression level may serve as a positive outcome predictor for AA treatment in CC.
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Subramanian VS, Srinivasan P, Wildman AJ, Marchant JS, Said HM. Molecular mechanism(s) involved in differential expression of vitamin C transporters along the intestinal tract. Am J Physiol Gastrointest Liver Physiol 2017; 312:G340-G347. [PMID: 27932501 PMCID: PMC5407060 DOI: 10.1152/ajpgi.00369.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 12/06/2016] [Accepted: 12/06/2016] [Indexed: 01/31/2023]
Abstract
Mammalian cells utilize two transporters for the uptake of ascorbic acid (AA), Na+-dependent vitamin C transporter SVCT-1 and SVCT-2. In the intestine, these transporters are involved in AA absorption and are expressed at the apical and basolateral membrane domains of the polarized epithelia, respectively. Little is known about the differential expression of these two transporters along the anterior-posterior axis of the intestinal tract and the molecular mechanism(s) that dictate this pattern of expression. We used mouse and human intestinal cDNAs to address these issues. The results showed a significantly lower rate of carrier-mediated AA uptake by mouse colon than jejunum. This was associated with a significantly lower level of expression of SVCT-1 and SVCT-2 at the protein, mRNA, and heterogeneous nuclear RNA (hnRNA) levels in the colon than the jejunum, implying the involvement of transcriptional mechanism(s). Similarly, expression levels of SVCT-1 and SVCT-2 mRNA and hnRNA were significantly lower in human colon. We also examined the levels of expression of hepatocyte nuclear factor 1α and specificity protein 1, which drive transcription of the Slc23a1 and Slc23a2 promoters, respectively, and found them to be markedly lower in the colon. Furthermore, significantly lower levels of the activating markers for histone (H3) modifications [H3 trimethylation of lysine 4 (H3K4me3) and H3 triacetylation of lysine 9 (H3K9ac)] were observed in the Slc23a1 and Slc23a2 promoters in the colon. These findings show, for the first time, that SVCT-1 and SVCT-2 are differentially expressed along the intestinal tract and that this pattern of expression is, at least in part, mediated via transcriptional/epigenetic mechanisms.NEW & NOTEWORTHY Our findings show, for the first time, that transporters of the water-soluble vitamin ascorbic acid (i.e., the vitamin C transporters SVCT-1 and SVCT-2) are differentially expressed along the length of the intestinal tract and that the pattern of expression is mediated, at least in part, by transcriptional and epigenetic mechanism(s) affecting both Slc23a1 and Slc23a2 genes.
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Affiliation(s)
- Veedamali S. Subramanian
- 1Departments of Medicine, Physiology, and Biophysics, University of California, Irvine, California; ,2Department of Veterans Affairs Medical Center, Long Beach, California; and
| | - Padmanabhan Srinivasan
- 1Departments of Medicine, Physiology, and Biophysics, University of California, Irvine, California; ,2Department of Veterans Affairs Medical Center, Long Beach, California; and
| | - Alexis J. Wildman
- 2Department of Veterans Affairs Medical Center, Long Beach, California; and
| | - Jonathan S. Marchant
- 3Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Hamid M. Said
- 1Departments of Medicine, Physiology, and Biophysics, University of California, Irvine, California; ,2Department of Veterans Affairs Medical Center, Long Beach, California; and
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Ascorbic acid, but not dehydroascorbic acid increases intracellular vitamin C content to decrease Hypoxia Inducible Factor -1 alpha activity and reduce malignant potential in human melanoma. Biomed Pharmacother 2016; 86:502-513. [PMID: 28012930 DOI: 10.1016/j.biopha.2016.12.056] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 12/09/2016] [Accepted: 12/14/2016] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Accumulation of hypoxia inducible factor-1 alpha (HIF-1α) in malignant tissue is known to contribute to oncogenic progression and is inversely associated with patient survival. Ascorbic acid (AA) depletion in malignant tissue may contribute to aberrant normoxic activity of HIF-1α. While AA supplementation has been shown to attenuate HIF-1α function in malignant melanoma, the use of dehydroascorbic acid (DHA) as a therapeutic means to increase intracellular AA and modulate HIF-1α function is yet to be evaluated. Here we compared the ability of AA and DHA to increase intracellular vitamin C content and decrease the malignant potential of human melanoma by reducing the activity of HIF-1α. METHODS HIF-1α protein accumulation was evaluated by western blot and transcriptional activity was evaluated by reporter gene assay using a HIF-1 HRE-luciferase plasmid. Protein expressions and subcellular localizations of vitamin C transporters were evaluated by western blot and confocal imaging. Intracellular vitamin C content following AA, ascorbate 2-phosphate (A2P), or DHA supplementation was determined using a vitamin C assay. Malignant potential was accessed using a 3D spheroid Matrigel invasion assay. Data was analyzed by One or Two-way ANOVA with Tukey's multiple comparisons test as appropriate with p<0.05 considered significant. RESULTS Melanoma cells expressed both sodium dependent vitamin C (SVCT) and glucose (GLUT) transporters for AA and DHA transport respectively, however advanced melanomas responded favorably to AA, but not DHA. Physiological glucose conditions significantly impaired intracellular vitamin C accumulation following DHA treatment. Consequently, A2P and AA, but not DHA treated cells demonstrated lower HIF-1α protein expression and activity, and reduced malignant potential. The ability of AA to regulate HIF-1α was dependent on SVCT2 function and SVCT2 was not significantly inhibited at pH representative of the tumor microenvironment. CONCLUSIONS The use of ascorbic acid as an adjuvant cancer therapy remains under investigated. While AA and A2P were capable of modulating HIF-1α protein accumulation/activity, DHA supplementation resulted in minimal intracellular vitamin C activity with decreased ability to inhibit HIF-1α activity and malignant potential in advanced melanoma. Restoring AA dependent regulation of HIF-1α in malignant cells may prove beneficial in reducing chemotherapy resistance and improving treatment outcomes.
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Eid W, Abdel-Rehim W. Vitamin C promotes pluripotency of human induced pluripotent stem cells via the histone demethylase JARID1A. Biol Chem 2016; 397:1205-1213. [DOI: 10.1515/hsz-2016-0181] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/22/2016] [Indexed: 01/06/2023]
Abstract
Abstract
Somatic cells can be reprogramed into induced pluripotent stem (iPS) cells by defined factors, which provide a powerful basis for personalized stem-cell based therapies. However, cellular reprograming is an inefficient and metabolically demanding process commonly associated with obstacles that hamper further use of this technology. Spontaneous differentiation of iPS cells cultures represents a significant hurdle that hinder obtaining high quality iPS cells for further downstream experimentation. In this study, we found that a natural compound, vitamin C, augmented pluripotency in iPS cells and reduced unwanted spontaneous differentiation during iPS cells maintenance. Gene expression analysis showed that vitamin C increased the expression of the histone demethylase JARID1A. Furthermore, through gain- and loss-of-function approaches, we show that JARID1A is a key effector in promoting pluripotency and reducing differentiation downstream of vitamin C. Our results therefore highlight a straightforward method for improving the pluripotency and quality of iPS cells; it also shows a possible role for H3K4me2/3 in cell fate determination and establishes a link between vitamin C and epigenetic regulation.
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26
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Hong JM, Kim JH, Kang JS, Lee WJ, Hwang YI. Vitamin C is taken up by human T cells via sodium-dependent vitamin C transporter 2 (SVCT2) and exerts inhibitory effects on the activation of these cells in vitro. Anat Cell Biol 2016; 49:88-98. [PMID: 27382510 PMCID: PMC4927435 DOI: 10.5115/acb.2016.49.2.88] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/08/2016] [Accepted: 04/06/2016] [Indexed: 01/11/2023] Open
Abstract
Vitamin C is an essential micronutrient that affects immune responses. T cells are one of the main players in acquired immunity and have been reported to be influenced by in vivo vitamin C supplementation. Yet, the way by which T cells uptake vitamin C and what direct effects vitamin C exerts on the cells are not known. To elucidate, we isolated human peripheral blood T cells and analyzed the expression of sodium-dependent vitamin C transporters (SVCT). T cells were activated in vitro in the absence or presence of vitamin C, before or after activation. As results, human T cells expressed SVCT2, but not SVCT1, and the expression level increased following activation. Vitamin C added in the culture media generally did not affect T-cell behaviors following activation, such as proliferation, apoptosis, expression of CD25 and CD69, and interleukin 2 secretion, regardless whether it was added before or after activation. However, exceptionally, high concentration vitamin C, when it was added before activation, but not after activation, did exert toxic effects on cell activation with respect to the above-mentioned parameters. In conclusion, we showed the expression of SVCT2 in human T cells for the first time. Vitamin C exerted toxic effects, at least in vitro, when the concentration was high and when it was given before activation. These toxic effects are not thought to be via anti-oxidant effects of vitamin C.
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Affiliation(s)
- Jun-Man Hong
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Korea
| | - Jin-Hee Kim
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Korea
| | - Jae Seung Kang
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Korea
| | - Wang Jae Lee
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Korea
| | - Young-Il Hwang
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Korea
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27
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Jung SA, Lee DH, Moon JH, Hong SW, Shin JS, Hwang IY, Shin YJ, Kim JH, Gong EY, Kim SM, Lee EY, Lee S, Kim JE, Kim KP, Hong YS, Lee JS, Jin DH, Kim T, Lee WJ. L-Ascorbic acid can abrogate SVCT-2-dependent cetuximab resistance mediated by mutant KRAS in human colon cancer cells. Free Radic Biol Med 2016; 95:200-8. [PMID: 27012422 DOI: 10.1016/j.freeradbiomed.2016.03.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 03/03/2016] [Accepted: 03/09/2016] [Indexed: 01/05/2023]
Abstract
Colon cancer patients with mutant KRAS are resistant to cetuximab, an antibody directed against the epidermal growth factor receptor, which is an effective clinical therapy for patients with wild-type KRAS. Numerous combinatorial therapies have been tested to overcome the resistance to cetuximab. However, no combinations have been found that can be used as effective therapeutic strategies. In this study, we demonstrate that L-ascorbic acid partners with cetuximab to induce killing effects, which are influenced by sodium-dependent vitamin C transporter 2 (SVCT-2) in human colon cancer cells with a mutant KRAS. L-Ascorbic acid treatment of human colon cancer cells that express a mutant KRAS differentially and synergistically induced cell death with cetuximab in a SVCT-2-dependent manner. The ectopic expression of SVCT-2 induced sensitivity to L-ascorbic acid treatment in human colon cancer cells that do not express SVCT-2, whereas the knockdown of endogenous SVCT-2 induced resistance to L-ascorbic acid treatment in SVCT-2-positive cells. Moreover, tumor regression via the administration of L-ascorbic acid and cetuximab in mice bearing tumor cell xenografts corresponded to SVCT-2 protein levels. Interestingly, cell death induced by the combination of L-ascorbic acid and cetuximab resulted in both apoptotic and necrotic cell death. These cell death mechanisms were related to a disruption of the ERK pathway and were represented by the impaired activation of RAFs and the activation of the ASK-1-p38 pathway. Taken together, these results suggest that resistance to cetuximab in human colon cancer patients with a mutant KRAS can be bypassed by L-ascorbic acid in an SVCT-2-dependent manner. Furthermore, SVCT-2 in mutant KRAS colon cancer may act as a potent marker for potentiating L-ascorbic acid co-treatment with cetuximab.
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Affiliation(s)
- Soo-A Jung
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Dae-Hee Lee
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Jai-Hee Moon
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Seung-Woo Hong
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Jae-Sik Shin
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Ih Yeon Hwang
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Yu Jin Shin
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Jeong Hee Kim
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Eun-Yeung Gong
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Seung-Mi Kim
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Eun Young Lee
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Seul Lee
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Jeong Eun Kim
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Kyu-Pyo Kim
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Yong Sang Hong
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Jung Shin Lee
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea
| | - Dong-Hoon Jin
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea; Department of Convergence Medicine, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea.
| | - TaeWon Kim
- Innovative Cancer Research, Asan Institute for Life Science, Republic of Korea; Department of Oncology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympicro-43gil, Songpa-gu, Seoul, Republic of Korea.
| | - Wang Jae Lee
- Department of Anatomy and Tumor Immunity Medical Research Center, Seoul National University College of Medicine, Seoul 110-744, Republic of Korea
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28
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Song B, Ye Z, Yang Y, Ma H, Zheng X, Jin D, Yuan J. Background-free in-vivo Imaging of Vitamin C using Time-gateable Responsive Probe. Sci Rep 2015; 5:14194. [PMID: 26373894 PMCID: PMC4570993 DOI: 10.1038/srep14194] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 08/17/2015] [Indexed: 11/23/2022] Open
Abstract
Sensitive optical imaging of active biomolecules in the living organism requires both a molecular probe specifically responsive to the target and a high-contrast approach to remove the background interference from autofluorescence and light scatterings. Here, a responsive probe for ascorbic acid (vitamin C) has been developed by conjugating two nitroxide radicals with a long-lived luminescent europium complex. The nitroxide radical withholds the probe on its “off” state (barely luminescent), until the presence of vitamin C will switch on the probe by forming its hydroxylamine derivative. The probe showed a linear response to vitamin C concentration with a detection limit of 9.1 nM, two orders of magnitude lower than that achieved using electrochemical methods. Time-gated luminescence microscopy (TGLM) method has further enabled real-time, specific and background-free monitoring of cellular uptake or endogenous production of vitamin C, and mapping of vitamin C in living Daphnia magna. This work suggests a rational design of lanthanide complexes for background-free small animal imaging of biologically functional molecules.
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Affiliation(s)
- Bo Song
- State Key Laboratory of Fine Chemicals, School of Chemistry,Dalian University of Technology, Dalian 116024, P. R. China
| | - Zhiqing Ye
- State Key Laboratory of Fine Chemicals, School of Chemistry,Dalian University of Technology, Dalian 116024, P. R. China
| | - Yajie Yang
- State Key Laboratory of Fine Chemicals, School of Chemistry,Dalian University of Technology, Dalian 116024, P. R. China
| | - Hua Ma
- State Key Laboratory of Fine Chemicals, School of Chemistry,Dalian University of Technology, Dalian 116024, P. R. China
| | - Xianlin Zheng
- Advanced Cytometry Labs, ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP),Macquarie University, NSW 2109, Sydney, Australia
| | - Dayong Jin
- Advanced Cytometry Labs, ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP),Macquarie University, NSW 2109, Sydney, Australia
| | - Jingli Yuan
- State Key Laboratory of Fine Chemicals, School of Chemistry,Dalian University of Technology, Dalian 116024, P. R. China
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Rahman F, Al Frouh F, Bordignon B, Fraterno M, Landrier JF, Peiretti F, Fontes M. Ascorbic acid is a dose-dependent inhibitor of adipocyte differentiation, probably by reducing cAMP pool. Front Cell Dev Biol 2014; 2:29. [PMID: 25364736 PMCID: PMC4207035 DOI: 10.3389/fcell.2014.00029] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/29/2014] [Indexed: 12/14/2022] Open
Abstract
Ascorbic acid (AA) is the active component of vitamin C and antioxidant activity was long considered to be the primary molecular mechanism underlying the physiological actions of AA. We recently demonstrated that AA is a competitive inhibitor of adenylate cyclase, acting as a global regulator of intracellular cyclic adenosine monophosphate (cAMP) levels. Our study, therefore, aimed to determine new targets of AA that would account for its potential effect on signal transduction, particularly during cell differentiation. We demonstrated that AA is an inhibitor of pre-adipocyte cell line differentiation, with a dose-dependent effect. Additionally, we describe the impact of AA on the expression of genes involved in adipogenesis and/or the adipocyte phenotype. Moreover, our data suggest that treatment with AA partially reverses lipid accumulation in mature adipocytes. These properties likely reflect the function of AA as a global regulator of the cAMP pool, since an analog of AA without any antioxidant properties elicited the same effect. Additionally, we demonstrated that AA inhibits adipogenesis in OP9 mesenchymal cell line and drives the differentiation of this line toward osteogenesis. Finally, our data suggest that the intracellular transporter SVCT2 is involved in these processes and may act as a receptor for AA.
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Affiliation(s)
- Fryad Rahman
- Nutrition, Obesity and Risk of Thrombosis, INSERM U 1062, INRA 1260, Aix-Marseille University Marseille, France
| | - Fadi Al Frouh
- Nutrition, Obesity and Risk of Thrombosis, INSERM U 1062, INRA 1260, Aix-Marseille University Marseille, France
| | - Benoit Bordignon
- Nutrition, Obesity and Risk of Thrombosis, INSERM U 1062, INRA 1260, Aix-Marseille University Marseille, France
| | - Marc Fraterno
- Service of Electron Microscope, Faculté de Médecine, Aix-Marseille University Marseille, France
| | - Jean-François Landrier
- Nutrition, Obesity and Risk of Thrombosis, INSERM U 1062, INRA 1260, Aix-Marseille University Marseille, France
| | - Franck Peiretti
- Nutrition, Obesity and Risk of Thrombosis, INSERM U 1062, INRA 1260, Aix-Marseille University Marseille, France
| | - Michel Fontes
- Nutrition, Obesity and Risk of Thrombosis, INSERM U 1062, INRA 1260, Aix-Marseille University Marseille, France
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Vitamin C facilitates pluripotent stem cell maintenance by promoting pluripotency gene transcription. Biochimie 2013; 95:2107-13. [PMID: 23954801 DOI: 10.1016/j.biochi.2013.08.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Accepted: 08/01/2013] [Indexed: 02/08/2023]
Abstract
Vitamin C has recently received attention because of its ability to improve induced pluripotent stem cells (iPSCs) generation [1-3] and maintain a blastocyst-like state in ES cells [4]. However, the underlying mechanisms are not fully understood. In this study, we found that vitamin C maintained the morphology of mouse embryonic stem cell (mESC) colonies and inhibited mESC differentiation. Gene expression profiling revealed that the genes down-regulated by vitamin C were grouped in the regulation of differentiation and development, while most of the up-regulated genes were enriched in the regulation of transcription involving numerous pluripotency factors, which was further confirmed by real time quantitative PCR. For the key pluripotency factor Nanog, vitamin C increased its promoter activity and protein level. In addition, pathway screening indicated that vitamin C may affect various signaling pathways. Our study provides new insights into vitamin C-mediated pluripotency maintenance of mESCs.
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31
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Subramanian VS, Nabokina SM, Patton JR, Marchant JS, Moradi H, Said HM. Glyoxalate reductase/hydroxypyruvate reductase interacts with the sodium-dependent vitamin C transporter-1 to regulate cellular vitamin C homeostasis. Am J Physiol Gastrointest Liver Physiol 2013; 304:G1079-86. [PMID: 23599041 PMCID: PMC3680717 DOI: 10.1152/ajpgi.00090.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The human sodium-dependent vitamin C transporter 1 (hSVCT1) contributes to cellular uptake of ascorbic acid (AA). Although different aspects of hSVCT1 cell biology have been extensively studied, nothing is currently known about the broader hSVCT1 interactome that modulates its role in cellular physiology. Here, we identify the enzyme human glyoxalate reductase/hydroxypyruvate reductase (hGR/HPR) as an hSVCT1 associated protein by yeast two-hybrid (Y2H) screening of a human liver cDNA library. The interaction between hSVCT1 and hGR/HPR was further confirmed by in vitro GST pull-down assay, in vivo coimmunoprecipitation and mammalian two-hybrid firefly luciferase assays. This interaction had functional significance as coexpression of hGR/HPR with hSVCT1 led to an increase in AA uptake. Reciprocally, siRNA-mediated knockdown of endogenous hGR/HPR led to an inhibition of AA uptake. Given that oxalate is a degradation product of vitamin C and hGR/HPR acts to limit cellular oxalate levels, this association physically couples two independent regulators of cellular oxalate production. Furthermore, confocal imaging of human liver HepG2 cells coexpressing GFP-hSVCT1 and hGR/HPR-mCherry demonstrated that these two proteins colocalize within a subpopulation of intracellular organelles. This provides a possible molecular basis for organellar AA transport and regulation of local glyoxylate/glycolate concentration in the vicinity of organelle membranes.
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Affiliation(s)
- Veedamali S. Subramanian
- 1Departments of Medicine, Physiology and Biophysics, University of California, Irvine, California; ,2Department of Veterans Affairs Medical Center, Long Beach, California; and
| | - Svetlana M. Nabokina
- 1Departments of Medicine, Physiology and Biophysics, University of California, Irvine, California; ,2Department of Veterans Affairs Medical Center, Long Beach, California; and
| | - Joseph R. Patton
- 3Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Jonathan S. Marchant
- 3Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Hamid Moradi
- 1Departments of Medicine, Physiology and Biophysics, University of California, Irvine, California; ,2Department of Veterans Affairs Medical Center, Long Beach, California; and
| | - Hamid M. Said
- 1Departments of Medicine, Physiology and Biophysics, University of California, Irvine, California; ,2Department of Veterans Affairs Medical Center, Long Beach, California; and
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32
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Chothe PP, Chutkan N, Sangani R, Wenger KH, Prasad PD, Thangaraju M, Hamrick MW, Isales CM, Ganapathy V, Fulzele S. Sodium-coupled vitamin C transporter (SVCT2): expression, function, and regulation in intervertebral disc cells. Spine J 2013; 13:549-57. [PMID: 23415019 DOI: 10.1016/j.spinee.2013.01.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 11/16/2012] [Accepted: 01/13/2013] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Vitamin C (ascorbic acid [AA]) is essential for the synthesis of collagen and also acts as an antioxidant in the intervertebral disc (IVD). However, there is very little information currently available on the identity of the transporter that facilitates AA entry into IVD cells and the factors that mediate the transport process. PURPOSE To investigate the expression of the two known isoforms of Na+ -coupled vitamin C transporter, SVCT1 and SVCT2, in IVD cells and its regulation by insulin-like growth factor 1 (IGF-1) and the steroid hormone dexamethasone. STUDY DESIGN To identify the expression and functional activity of the sodium-dependent vitamin C transporter (SVCT) in the IVD. METHODS Uptake studies were carried out with rabbit annulus fibrosis and nucleus pulposus cells in 24-well plates using [14C]-AA. To characterize SVCT transporter, uptake was done in the presence and absence of Na+ in the uptake buffer. Time dependency, Na+ activation kinetics, saturation kinetics, and substrate selectivity studies were performed. Regulatory studies were performed in the presence of IGF-1 and the steroid hormone dexamethasone. Gene expression was analyzed by quantitative polymerase chain reaction. RESULTS Our real-time polymerase chain reaction results showed the presence of SVCT2 but not SVCT1 in IVD cells. Uptake of vitamin C in IVD cells is Na+ dependent and saturable. The Michaelis constant for the process is 96±11 μM. The activation of vitamin C uptake by Na+ exhibits a sigmoidal relationship, indicating involvement of more than one Na+ in the activation process. The uptake system does not recognize any other water-soluble vitamin as a substrate. Immunocytochemical analysis shows robust expression of SVCT2 protein in IVD cells. The growth factors IGF-1 and the steroid hormone dexamethasone upregulate the expression of SVCT2 in IVD cells. CONCLUSIONS Our studies demonstrate that the active SVCT2 is expressed in IVD cells and that the expression of this transporter is regulated by growth factors IGF-1 and dexamethasone.
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Affiliation(s)
- Paresh P Chothe
- Department of Biochemistry and Molecular Biology, Georgia Health Science University, 1459 Laney Walker Blvd, Augusta, GA 30912, USA
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Bürzle M, Suzuki Y, Ackermann D, Miyazaki H, Maeda N, Clémençon B, Burrier R, Hediger MA. The sodium-dependent ascorbic acid transporter family SLC23. Mol Aspects Med 2013; 34:436-54. [PMID: 23506882 DOI: 10.1016/j.mam.2012.12.002] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 11/16/2012] [Indexed: 12/31/2022]
Affiliation(s)
- Marc Bürzle
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
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Subramanian VS, Subramanya SB, Ghosal A, Marchant JS, Harada A, Said HM. Modulation of function of sodium-dependent vitamin C transporter 1 (SVCT1) by Rab8a in intestinal epithelial cells: studies utilizing Caco-2 cells and Rab8a knockout mice. Dig Dis Sci 2013; 58:641-9. [PMID: 23014846 PMCID: PMC3547156 DOI: 10.1007/s10620-012-2388-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 08/24/2012] [Indexed: 01/19/2023]
Abstract
BACKGROUND Ascorbic acid (AA) is required for normal human health and development. Human intestine expresses two sodium-dependent vitamin C transporters (hSVCT-1 and -2) that mediate cellular AA transport, with hSVCT1 targeting to the apical membrane of polarized epithelia. Studies have shown a role for the Rab8a in the apical membrane targeting of transporters in intestinal cells. AIMS The purpose of this study was to determine whether Rab8a impacts the function and/or targeting of hSVCT1, and intestinal AA uptake. METHODS We used human intestinal cells and cells from a Rab8a knockout mouse. (14)C-AA uptake was performed to determine functionality. PCR and western blotting were performed to determine RNA and protein expression, respectively. Confocal imaging was performed to determine co-localization. RESULTS We show that hSVCT1 co-localized with Rab8a in intestinal cells. Knockdown of Rab8a lead to a significant inhibition in AA uptake and cell surface biotinylation studies revealed a lower cell surface expression of hSVCT1 in Rab8a siRNA-treated cells. Similarly, in the small intestine of a Rab8a knockout mouse, AA uptake was significantly inhibited. This effect again resulted from a decreased expression level of mSVCT1 protein, even though mRNA expression of SVCT1 was similar in intestinal cells from Rab8a knockout and wild-type litter-mates. The latter data are suggestive of enhanced lysosomal degradation of hSVCT1 protein in Rab8a-deficient cells; indeed, confocal imaging of Rab8a siRNA-treated intestinal cells revealed a strong overlap between hSVCT1-YFP and LAMP1-RFP. CONCLUSIONS These findings show a role for Rab8a in the physiological function of hSVCT1 in intestinal epithelia.
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Affiliation(s)
- Veedamali S. Subramanian
- Departments of Medicine, Physiology and Biophysics, University of California, Irvine, CA 92697
,Department of Veterans Affairs Medical Center, Long Beach, CA 90822
,To whom correspondence may be addressed: , Phone: 562-826-5803; Fax: 562-826-5018
| | - Sandeep B. Subramanya
- Departments of Medicine, Physiology and Biophysics, University of California, Irvine, CA 92697
,Department of Veterans Affairs Medical Center, Long Beach, CA 90822
| | - Abhisek Ghosal
- Departments of Medicine, Physiology and Biophysics, University of California, Irvine, CA 92697
,Department of Veterans Affairs Medical Center, Long Beach, CA 90822
| | | | | | - Hamid M. Said
- Departments of Medicine, Physiology and Biophysics, University of California, Irvine, CA 92697
,Department of Veterans Affairs Medical Center, Long Beach, CA 90822
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Du J, Cullen JJ, Buettner GR. Ascorbic acid: chemistry, biology and the treatment of cancer. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1826:443-57. [PMID: 22728050 PMCID: PMC3608474 DOI: 10.1016/j.bbcan.2012.06.003] [Citation(s) in RCA: 478] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 06/11/2012] [Accepted: 06/13/2012] [Indexed: 12/14/2022]
Abstract
Since the discovery of vitamin C, the number of its known biological functions is continually expanding. Both the names ascorbic acid and vitamin C reflect its antiscorbutic properties due to its role in the synthesis of collagen in connective tissues. Ascorbate acts as an electron-donor keeping iron in the ferrous state thereby maintaining the full activity of collagen hydroxylases; parallel reactions with a variety of dioxygenases affect the expression of a wide array of genes, for example via the HIF system, as well as via the epigenetic landscape of cells and tissues. In fact, all known physiological and biochemical functions of ascorbate are due to its action as an electron donor. The ability to donate one or two electrons makes AscH(-) an excellent reducing agent and antioxidant. Ascorbate readily undergoes pH-dependent autoxidation producing hydrogen peroxide (H(2)O(2)). In the presence of catalytic metals this oxidation is accelerated. In this review, we show that the chemical and biochemical nature of ascorbate contribute to its antioxidant as well as its prooxidant properties. Recent pharmacokinetic data indicate that intravenous (i.v.) administration of ascorbate bypasses the tight control of the gut producing highly elevated plasma levels; ascorbate at very high levels can act as prodrug to deliver a significant flux of H(2)O(2) to tumors. This new knowledge has rekindled interest and spurred new research into the clinical potential of pharmacological ascorbate. Knowledge and understanding of the mechanisms of action of pharmacological ascorbate bring a rationale to its use to treat disease especially the use of i.v. delivery of pharmacological ascorbate as an adjuvant in the treatment of cancer.
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Affiliation(s)
- Juan Du
- Department of Radiation Oncology, University of Iowa College of Medicine, Iowa City, IA, USA
| | - Joseph J. Cullen
- Department of Radiation Oncology, University of Iowa College of Medicine, Iowa City, IA, USA
- Department of Surgery, University of Iowa College of Medicine, Iowa City, IA, USA
- Holden Comprehensive Cancer Center, USA
- Veterans Affairs Medical Center, Iowa City, IA, USA
| | - Garry R. Buettner
- Department of Radiation Oncology, University of Iowa College of Medicine, Iowa City, IA, USA
- Holden Comprehensive Cancer Center, USA
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Minegaki T, Takara K, Hamaguchi R, Tsujimoto M, Nishiguchi K. Factors affecting the sensitivity of human-derived esophageal carcinoma cell lines to 5-fluorouracil and cisplatin. Oncol Lett 2012; 5:427-434. [PMID: 23420099 PMCID: PMC3573136 DOI: 10.3892/ol.2012.1014] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/26/2012] [Indexed: 02/04/2023] Open
Abstract
Effective chemotherapy against esophageal carcinoma is considered achievable with a combination of 5-fluorouracil (5-FU) and cisplatin (CDDP). However, chemo-therapy remains ineffective in certain patients. The aim of this study was to clarify the factors which affect sensitivity to 5-FU and CDDP. The effects of factors known to influence sensitivity to 5-FU and CDDP, namely transporters, DNA repair enzymes and metabolic enzymes, were examined. mRNA levels of four transporters, SLC22A2, SLC23A2, ABCB1 and ABCC2, two DNA repair-related enzymes, Rad51 and MSH2, and one metabolic enzyme, dihydropyrimidine dehydrogenase (DPYD), showed a strong correlation (|r|>0.7) with IC50 values for 5-FU. In addition, the mRNA levels of ABCC2, MSH2 and DPYD showed a strong correlation (|r|>0.7) with the IC50 values for CDDP. Gimeracil, a DPYD inhibitor, enhanced the sensitivity of some cells to 5-FU but decreased the sensitivity of all the cells to CDDP. The inhibitory effects of ABCC2 with MK571 did not correspond to those observed in the correlation analysis. In conclusion, mRNA levels of SLC22A2, SLC23A2, ABCB1, ABCC2, Rad51, MSH2 and DPYD were confirmed to be strongly correlated with IC50 values for 5-FU, and mRNA levels of ABCC2, MSH2 and DPYD were confirmed to be strongly correlated with IC50 values for CDDP. In addition, the inhibition of DPYD appeared to affect the cytotoxicity of CDDP.
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Affiliation(s)
- Tetsuya Minegaki
- Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414
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Mardones L, Zúñiga FA, Villagrán M, Sotomayor K, Mendoza P, Escobar D, González M, Ormazabal V, Maldonado M, Oñate G, Angulo C, Concha II, Reyes AM, Cárcamo JG, Barra V, Vera JC, Rivas CI. Essential role of intracellular glutathione in controlling ascorbic acid transporter expression and function in rat hepatocytes and hepatoma cells. Free Radic Biol Med 2012; 52:1874-87. [PMID: 22348976 DOI: 10.1016/j.freeradbiomed.2012.02.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 02/07/2012] [Accepted: 02/09/2012] [Indexed: 01/21/2023]
Abstract
Although there is in vivo evidence suggesting a role for glutathione in the metabolism and tissue distribution of vitamin C, no connection with the vitamin C transport systems has been reported. We show here that disruption of glutathione metabolism with buthionine-(S,R)-sulfoximine (BSO) produced a sustained blockade of ascorbic acid transport in rat hepatocytes and rat hepatoma cells. Rat hepatocytes expressed the Na(+)-coupled ascorbic acid transporter-1 (SVCT1), while hepatoma cells expressed the transporters SVCT1 and SVCT2. BSO-treated rat hepatoma cells showed a two order of magnitude decrease in SVCT1 and SVCT2 mRNA levels, undetectable SVCT1 and SVCT2 protein expression, and lacked the capacity to transport ascorbic acid, effects that were fully reversible on glutathione repletion. Interestingly, although SVCT1 mRNA levels remained unchanged in rat hepatocytes made glutathione deficient by in vivo BSO treatment, SVCT1 protein was absent from the plasma membrane and the cells lacked the capacity to transport ascorbic acid. The specificity of the BSO treatment was indicated by the finding that transport of oxidized vitamin C (dehydroascorbic acid) and glucose transporter expression were unaffected by BSO treatment. Moreover, glutathione depletion failed to affect ascorbic acid transport, and SVCT1 and SVCT2 expression in human hepatoma cells. Therefore, our data indicate an essential role for glutathione in controlling vitamin C metabolism in rat hepatocytes and rat hepatoma cells, two cell types capable of synthesizing ascorbic acid, by regulating the expression and subcellular localization of the transporters involved in the acquisition of ascorbic acid from extracellular sources, an effect not observed in human cells incapable of synthesizing ascorbic acid.
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Affiliation(s)
- Lorena Mardones
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160C, Concepción, Chile
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Bürzle M, Hediger MA. Functional and Physiological Role of Vitamin C Transporters. CO-TRANSPORT SYSTEMS 2012. [DOI: 10.1016/b978-0-12-394316-3.00011-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Bioavailability of vitamin C from mashed potatoes and potato chips after oral administration in healthy Japanese men. Br J Nutr 2011; 107:885-92. [DOI: 10.1017/s0007114511003643] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Potato (Solanum tuberosum) tubers contain vitamin C (VC) and commercial potato chips have more VC content per wet weight by dehydration during frying. However, intestinal absorption of VC from orally ingested potatoes and its transfer to the blood remains questionable. The present study was designed to determine whether the dietary consumption of potatoes affects VC concentration in plasma and urinary excretion of VC in human subjects. After overnight fasting, five healthy Japanese men between 22 and 27 years of age consumed 87 g mashed potatoes and 282 g potato chips. Each portion contained 50 mg of VC, 50 mg VC in mineral water and mineral water. Before and after a single episode of ingestion, blood and urine samples were collected every 30 min or 1 h for 8 h. When measured by subtraction of the initial baseline value before administration of potatoes from the values measured throughout the 8 h test period, plasma VC concentrations increased almost linearly up to 3 h. Subsequently, the values of potato-fed subjects were higher than those of water, but did not differ significantly from those of VC in water (P = 0·14 andP = 0·5). Less VC tended to be excreted in urine during the 8 h test than VC in water alone (17·0 (sem7·5) and 25·9 (sem8·8)v.47·9 (sem17·9) μmol/mmol creatinine). Upon human consumption, mashed potatoes and potato chips provide VC content that is effectively absorbed in the intestine and transferred to the blood. Clearly, potatoes are a readily available source of dietary VC.
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Ghosal A, Subramanian VS, Said HM. Role of the putative N-glycosylation and PKC-phosphorylation sites of the human sodium-dependent multivitamin transporter (hSMVT) in function and regulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2073-80. [PMID: 21570947 DOI: 10.1016/j.bbamem.2011.04.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 04/16/2011] [Accepted: 04/22/2011] [Indexed: 10/18/2022]
Abstract
The sodium-dependent multivitamin transporter (SMVT) is a major biotin transporter in a variety of tissues including the small intestine. The human SMVT (hSMVT) polypeptide is predicted to have four N-glycosylation sites and two putative PKC phosphorylation sites but their role in the function and regulation of the protein is not known and was examined in this investigation. Our results showed that the hSMVT protein is glycosylated and that this glycosylation is important for its function. Studies utilizing site-directed mutagenesis revealed that the N-glycosylation sites at positions Asn(138) and Asn(489) are important for the function of hSMVT and that mutating these sites significantly reduces the V(max) of the biotin uptake process. Mutating the putative PKC phosphorylation site Thr(286) of hSMVT led to a significant decrease in the PMA-induced inhibition in biotin uptake. The latter effect was not mediated via changes in the level of expression of the hSMVT protein and mRNA or in its level of expression at the cell membrane. These findings demonstrate that the hSMVT protein is glycosylated, and that glycosylation is important for its function. Furthermore, the study shows a role for the putative PKC-phosphorylation site Thr(286) of hSMVT in the PKC-mediated regulation of biotin uptake.
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Affiliation(s)
- Abhisek Ghosal
- Department of Medicine and Physiology/Biophysics, University of California, Irvine, CA 92697, USA
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Petroianu A, Alberti LR. Efeito da suplementação oral de vitamina C na resistência anastomótica intestinal. Rev Col Bras Cir 2011; 38:54-8. [DOI: 10.1590/s0100-69912011000100010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2001] [Accepted: 03/12/2001] [Indexed: 11/22/2022] Open
Abstract
OBJETIVO: Comparar a resistência cicatricial de anastomoses e de segmentos íntegros jejunais de ratos, submetidos à administração de vitamina C, em distintos períodos pós-operatórios. MÉTODOS: Foram estudados 50 ratos Wistar, submetidos a enterotomia seguida de anastomose término-terminal de segmento jejunal, a 10 cm da flexura duodenojejunal. Os animais foram distribuídos em dois grupos (n=25): Grupo I - controle; Grupo II - administração de vitamina C oral 100 mg/kg. Avaliaram-se as pressões de ruptura anastomótica e do segmento íntegro jejunal nos 3º, 5º, 7º, 21º E 28º dias do pós-peratório. RESULTADOS: Os ratos que receberam vitamina C apresentaram pressão de ruptura anastomótica maior nos 5º, 7º, e 28º dias pós-operatórios. O mesmo ocorreu com as pressões de ruptura do segmento íntegro jejunal dos ratos. CONCLUSÃO: A vitamina C aumentou a resistência das anastomoses jejunais dos ratos, tanto no pós-operatório imediato quanto no tardio. Além disso, a resistência final dos segmentos jejunais íntegros dos ratos submetidos à administração de vitamina C foi significativamente maior do que no Grupo Controle.
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Corti A, Casini AF, Pompella A. Cellular pathways for transport and efflux of ascorbate and dehydroascorbate. Arch Biochem Biophys 2010; 500:107-15. [PMID: 20494648 DOI: 10.1016/j.abb.2010.05.014] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 05/13/2010] [Accepted: 05/14/2010] [Indexed: 11/17/2022]
Abstract
The mechanisms allowing the cellular transport of ascorbic acid represent a primary aspect for the understanding of the roles played by this vitamin in pathophysiology. Considerable research effort has been spent in the field, on several animal models and different cell types. Several mechanisms have been described to date, mediating the movements of different redox forms of ascorbic acid across cell membranes. Vitamin C can enter cells both in its reduced and oxidized form, ascorbic acid (AA) and dehydroascorbate (DHA), utilizing respectively sodium-dependent transporters (SVCT) or glucose transporters (GLUT). Modulation of SVCT expression and function has been described by cytokines, steroids and post-translational protein modification. Cellular uptake of DHA is followed by its intracellular reduction to AA by several enzymatic and non-enzymatic systems. Efflux of vitamin C has been also described in a number of cell types and different pathophysiological functions were proposed for this phenomenon, in dependence of the cell model studied. Cellular efflux of AA is mediated through volume-sensitive (VSOAC) and Ca(2+)-dependent anion channels, gap-junction hemichannels, exocytosis of secretory vesicles and possibly through homo- and hetero-exchange systems at the plasma membrane level. Altogether, available data suggest that cellular efflux of ascorbic acid - besides its uptake - should be taken into account when evaluating the cellular homeostasis and functions of this important vitamin.
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Affiliation(s)
- Alessandro Corti
- Dipartimento di Patologia Sperimentale, Università di Pisa, Italy.
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Reidling JC, Rubin SA. Promoter analysis of the human ascorbic acid transporters SVCT1 and 2: mechanisms of adaptive regulation in liver epithelial cells. J Nutr Biochem 2010; 22:344-50. [PMID: 20471816 DOI: 10.1016/j.jnutbio.2010.03.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 02/22/2010] [Accepted: 03/02/2010] [Indexed: 11/28/2022]
Abstract
Ascorbic acid, the active form of vitamin C, is a vital antioxidant in the human liver, yet the molecular mechanisms involved in the regulation of ascorbic acid transporters [human sodium-dependent vitamin C transporters (hSVCT) 1 and 2] in liver cells are poorly understood. Therefore, we characterized the minimal promoter regions of hSVCT1 and 2 in cultured human liver epithelial cells (HepG2) and examined the effects of ascorbic acid deprivation and supplementation on activity and regulation of the transport systems. Identified minimal promoters required for basal activity were found to include multiple cis regulatory elements, whereas mutational analysis demonstrated that HNF-1 sites in the hSVCT1 promoter and KLF/Sp1 sites in the hSVCT2 promoter were essential for activities. When cultured in ascorbic acid deficient or supplemented media, HepG2 cells demonstrated significant (P<.01) and specific reciprocal changes in [(14)C]-Ascorbic acid uptake, and in hSVCT1 mRNA and protein levels as well as hSVCT1 promoter activity. However, no significant changes in hSVCT2 expression or promoter activity were observed during ascorbic acid deficient or supplemented conditions. We mapped the ascorbic acid responsive region in the hSVCT1 promoter and determined that HNF-1 sites are important for the adaptive regulation response. The results of these studies further characterize the hSVCT1 and 2 promoters establish that ascorbic acid uptake by human liver epithelial cells is adaptively regulated and show that transcriptional mechanisms via HNF-1 in the hSVCT1 promoter may, in part, be involved in this regulation.
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Ascorbic acid depletion enhances expression of the sodium-dependent vitamin C transporters, SVCT1 and SVCT2, and uptake of ascorbic acid in livers of SMP30/GNL knockout mice. Arch Biochem Biophys 2010; 496:38-44. [DOI: 10.1016/j.abb.2010.01.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 01/23/2010] [Accepted: 01/25/2010] [Indexed: 11/23/2022]
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Subramanian VS, Marchant JS, Said HM. Molecular determinants dictating cell surface expression of the human sodium-dependent vitamin C transporter-2 in human liver cells. Am J Physiol Gastrointest Liver Physiol 2010; 298:G267-74. [PMID: 19926816 PMCID: PMC2822508 DOI: 10.1152/ajpgi.00435.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The human sodium-dependent vitamin C transporter-2 (hSVCT2) plays an important role in cellular accumulation of ascorbic acid in liver cells. However, little is known about the molecular determinants that direct hSVCT2 to the cell surface in hepatocytes. We addressed this issue using live cell imaging methods to resolve the distribution and trafficking of truncated or mutated hSVCT2 constructs in a cellular model of human hepatocytes, HepG2 cells. Whereas a full-length hSVCT2-yellow fluorescent protein (YFP) fusion protein was functionally expressed at the cell surface in HepG2 cells, serial truncation and mutation analysis demonstrated an essential role for both NH(2)- and COOH-terminal sequence(s) for cell surface expression and function. Video-rate confocal imaging showed evidence of dynamic hSVCT2-YFP containing intracellular trafficking vesicles, the motility of which was impaired following disruption of microtubules using nocodazole. However, in a HepG2 cell line stably expressing hSVCT2-YFP at the cell surface, plasma membrane levels of hSVCT2 were unaffected by inhibition of microtubule-associated motor proteins; rather, surface expression of hSVCT2-YFP was increased following treatment with myosin inhibitors. Together, these results show that 1) both NH(2)- and COOH-terminal sequences are essential for proper localization of hSVCT2, 2) cell surface delivery is dependent on intact microtubules, and 3) peripheral microfilaments regulate insertion and retrieval of hSVCT2 into the plasma membrane.
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Affiliation(s)
- Veedamali S. Subramanian
- Departments of 1Medicine, ,2Department of Physiology and Biophysics, University of California, Irvine, California; ,4Department of Veterans Affairs Medical Center, Long Beach, California
| | - Jonathan S. Marchant
- 3Department of Pharmacology, University of Minnesota Medical School, Minnesota; and
| | - Hamid M. Said
- Departments of 1Medicine, ,2Department of Physiology and Biophysics, University of California, Irvine, California; ,4Department of Veterans Affairs Medical Center, Long Beach, California
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Rivas CI, Zúñiga FA, Salas-Burgos A, Mardones L, Ormazabal V, Vera JC. Vitamin C transporters. J Physiol Biochem 2008; 64:357-75. [DOI: 10.1007/bf03174092] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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