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Clinical Trials |
Cancer Center Karolinska, Immune and Gene Therapy Laboratory, and Radiumhemmet, Department of Oncology and Pathology, Karolinska Institutet, S-17176 Stockholm, Sweden [K-J. M., M. P., T. O., F. I., B. G., J-E. F., G. M., R. K.], and CALAB Research /NOVA Medical Flow Cytometry Laboratory, 11281 Stockholm, Sweden [R. L.]
| ABSTRACT |
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Experimental Design: This hypothesis was here tested in twelve patients with colorectal cancer (Dukes C and D) who, prior to intervention with chemo- or radiotherapy, received a daily dose of 750 mg of vitamin E during a period of 2 weeks.
Results: Short-term supplementation with high doses of dietary vitamin E leads to increased CD4:CD8 ratios and to enhanced capacity by their T cells to produce the T helper 1 cytokines interleukin 2 and IFN-
. In 10 of 12 patients, an increase of 10% or more (average, 22%) in the number of T cells producing interleukin 2 was seen after 2 weeks of vitamin E supplementation, as compared with peripheral blood monocyte samples taken before treatment (P = 0.02). Interestingly, there seemed to be a more pronounced stimulatory effect by vitamin E on naïve (CD45RA+) T helper cells as compared with T cells with a memory/activated phenotype.
Conclusions: Dietary vitamin E may be used to improve the immune functions in patients with advanced cancer, as a supplement to more specific immune interventions.
| INTRODUCTION |
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Multiple factors may contribute to tumor-induced immune suppression. These include Fas-FasL interaction leading to T-cell apoptosis, shown to involve caspase 3-mediated cleavage of CD3
(23)
, as well as tumor-derived gangliosides inducing defective nuclear factor-
B activation in renal cell carcinoma lines (24)
. Recently several observations indicate that a chronic inflammatory condition develops in patients with advanced cancer, causing oxidative stress that can shut off immune functions, including those of T and NK cells. Free oxygen radicals produced by macrophages isolated from metastatic lymph nodes or from mice with experimental tumors were able to inhibit nonspecific and tumor-specific cytotoxicity and down-regulate signal transduction molecules (25, 26, 27)
. Monocytes recovered from human PBMCs can inhibit autologous NK cell-mediated cytotoxicity via secretion of H2O2, leading to the induction of apoptosis (28)
. In addition, macrophage-derived nitric oxide reduces the phosphorylation and activation of JAK3/STAT5 signal transduction proteins, thus inhibiting the proliferative responses of T cells to IL-2 (29)
. Furthermore we recently reported that micromolar levels of hydrogen peroxide selectively inhibited Th1 cytokine production in memory/activated T cells and that this inhibition correlated with the blocking of nuclear factor-
B activation (30)
.
Therapeutic interventions aimed to protect the immune system in cancer patients from damage caused by oxidative stress may, therefore, enhance their immune competence. This hypothesis was here tested in patients with advanced colorectal cancer, a patient group known to have defects in their capacity to produce Th1 cytokines in response to mitogen stimulation (14
, 15
, 31) . Twelve patients with colorectal cancer [Dukes C (2 patients) or D (10 patients)] were given high doses of dietary vitamin E in combination with vitamin C and selenium at RDA levels during a period of 2 weeks. Vitamin C and selenium were included for their capacity to recycle vitamin E, thus allowing vitamin E to function optimally (32, 33, 34, 35)
. Changes in the capacity of patients lymphocytes to respond to mitogen stimulation were evaluated. It was demonstrated that all subsets of T cells (CD4+, CD8+, CD45RO+, and CD45RO-) had enhanced capacity to produce IL-2 after 2 weeks of vitamin E treatment. Furthermore, significantly more cytotoxic T cells (CD8+) were capable of IFN-
production after treatment. Possible mechanisms behind the immunostimulatory effect of vitamin E and the role of the Th1 cytokines in tumor immunity are discussed. It is suggested that vitamin E may be used as an adjuvant to more specific immunotherapy that is dependent on a functional Th1 response.
| PATIENTS AND METHODS |
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Treatment Plan.
All of the patients were treated as outpatients. They received a total daily dose of 750 mg of vitamin E (RDA, 810 mg), 60ug selenium, and 90 mg vitamin C. This dose was distributed as follows: (100 mg vitamin E; ACO AB, Sweden), 3 tablets in the morning and 4 in the evening, OxiGard (50 mg vitamin E, 60 µg selenium, and 90 mg vitamin C; ACO AB, Sweden) 1 tablet every morning. Treatment period was 15 days. Patients underwent physical examinations on day 1 and 15.
Cells.
Patients PBLs were isolated by Ficoll Paque (Pharmacia Biotech AB; Uppsala, Sweden) gradient centrifugation for 20 min at 20°C before and after vitamin E treatment and were frozen in FCS 10% DMSO (Sigma, Stockholm, Sweden) for later analyses of their capacity to produce cytokines. Coded samples obtained before and after vitamin E treatment were analyzed in parallel.
Lymphocyte Activation for the Cytokine-staining Experiments.
PBMCs were thawed and washed, and the lymphocyte concentration was adjusted to 1 x 106 cells/ml. The cellular viability in all of the experiments was higher than 97% as determined with 7-aminoactinomycin D (Sigma). The lymphocytes were stimulated for 4 h at 37°C with PMA and Ionomycin (Sigma) in the presence of 10 µg/ml Brefeldin (Sigma; Ref. 36
).
Measurements of Plasma
-Tocopherol.
Plasma was collected after the gradient centrifugation as described above and was frozen at -20°C. Plasma was protected from daylight until measurements were performed. The
-tocopherol quantification was performed by a reverse-phase high-performance liquid chromatography method as described elsewhere (37)
.
FACS Analysis.
A four-color method was used. The cells were first stained for surface antigens (30 min at 4°C) with anti-CD45RO-FITC (Dakopatts), anti-CD8-PerCP, and anti-CD3-APC (BDIS Biosciences, Stockholm, Sweden). Thereafter, the lymphocytes were permeabilized with FACS-lysing solution and with FACS permeabilizing solution (BDIS Biosciences), and were stained for 10 min at room temperature in the dark with PE-conjugated mAbs directed to IL-2, IFN-
, IL-10, and TNF-
, (BDIS Biosciences). The staining protocol included isotype controls for both surface and cytoplasmic staining. The stimulation and permeabilization procedures were checked by cytoplasmic staining for CD69 (BDIS Biosciences) and vimentin (Serotec, Oslo, Norway). After staining, the cells were fixed with CellFix (BDIS Biosciences). Acquisition was performed in less than 2 h. The flow cytometric measurements were performed on a FACS Calibur (Becton Dickinson, Stockholm, Sweden). The instrument performance was checked daily with bead calibrators QC Windows, CaliBRITE, and Q1000, and monthly with both beads and cells as described previously (38)
. Data of at least 10,000 cells/sample were collected. Data analysis was done with Cell Quest software (BDIS Biosciences) according to a standardized pattern-protocol. The background fluorescence was determined with markers applied on the isotype control cytograms and was in all cases <1%. Because all analyzed cells were T cells (CD3+), the CD8- lymphocytes were considered CD4+, and the CD45RO- lymphocytes were considered CD45RA+.
IFN-
ELISA.
PBMCs were thawed and washed, and the lymphocyte concentration was adjusted to 1 x 106 cells/ml. Cells were seeded in triplicate cultures in 24-well plates (Costar, Corning Incorporated) and stimulated for 24 h by OKT-3 or control antibody at 100 ng/ml. Supernatants were harvested and the IFN-
content was measured by an ELISA. Briefly, 96-well plates (Maxisorp; Nalge Nunc International, Taastrup, Denmark) were coated with 4 µg/ml of capturing antibody, antihuman IFN-
(mAb 1-D1K; Mabtech AB, Stockholm, Sweden) at 4°C for 18 h and then washed two times in wash buffer (PBS with 0.05% Tween 20) and blocked in blocking solution (PBS with 1% BSA and 0.05% Tween) for 1 h at 37°C. Sample and standard were added to wells in triplicate (100 µl/well) and incubated for 2 h at 37°C. Plates were washed and secondary antibody (7-B6-1-Biotin; Mabtech AB) was added at 0.75 µg/ml and incubated for 2 h at 37°C. Next, streptavidin-ALP (Mabtech AB, Stockholm) was added and plates were incubated for 30 min at 37°C. After washing, substrate (alkaline phosphatase pNPP; Sigma, Stockholm, Sweden) was added and incubated for 20 min before plates were read at 405 nm in an ELISA reader.
Statistical Analysis.
Statistical analysis was performed using two-tailed, paired Students t test. Significance was accepted at P < 0.05.
| RESULTS |
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Increased Plasma
-Tocopherol Levels.
As a result of the treatment, patients enhanced their plasma levels of
-tocopherol from 16.9 (range, 13.622.8) to 39.5 µmol/liter (23.357.7), the reference interval for tocopherol being 13.536.8 µmol/liter (Fig. 1)
. The increase in plasma
-tocopherol levels was statistically significant (P < 0.001). This analysis also served as a quantitative test for the treatment compliance among patients ensuring adequate intake of prescribed vitamins.
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There also seemed to be a diverse effect of vitamin E on Th1 versus Th2 responses, inasmuch as no statistically significant changes could be observed for IL-10 production. The average percentage of T cells that produced IL-10 in response to PMA/Ionomycin before vitamin E treatment was 16%; and after vitamin E treatment, it remained low (17%).
Increased Number of IFN-
-producing CD8+ CD45RO+ T Cells after Vitamin E Treatment.
The increases in IFN-
responses after vitamin E administration were more variable and of less magnitude than for IL-2. Statistically significant increases in the number of IFN-
-producing cells were seen in CD8+ T cells with a memory/activated phenotype as defined by expression of CD45RO (P < 0.05; Fig. 5A
). In 6 of 6 randomly selected donors, the increased number of IFN-
-producing cells correlated with an enhanced IFN-
release by PBMCs, stimulated by anti-CD3 as measured by ELISA (P = 0.014; Fig. 5B
). Changes in TNF-
production were not statistically significant (data not shown).
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| DISCUSSION |
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in response to stimulation. Vitamin E is a lipid-soluble antioxidant that stimulates T-helper cell activity in a dose-dependent manner in mice immunized with a hapten-carrier conjugate (40) . Also, increased proliferative responses and IL-2 production has been described in old rats (41) . Furthermore, vitamin E counteracts the age-related decline of the cellular immune response, both in humans and in mice, by lowering macrophage prostaglandin E2 production (42, 43, 44, 45) . Vitamin E may decrease the incidence of prostate cancer in smoking men, as shown in a large primary prevention trial that is being followed up in the recently launched SELECT trial (the study of Selenium and Vitamin E Cancer Prevention Trial; Refs. 46 , 47 ). Whether this effect is mediated via influence on the immune system or by other mechanisms is unknown.
In our study, vitamin E promoted both IL-2 and IFN-
production by T cells. This was shown by staining for intracellular cytokines after stimulation with PMA/Ionomycin (Figs. 3
, 4
, and 5
) and was confirmed in six randomly selected patients by ELISA experiments on supernatants from cultures stimulated with PMA/Ionomycin (data not shown) or OKT-3 (anti-CD3 mAb; Fig. 5B
). In contrast, no significant induction of IL-10 production was observed as a result of vitamin E supplementation, favoring a Th1 response in these patients. We also describe a tendency toward a more pronounced effect of vitamin E in naïve T cells as compared with memory/activated T cells. These observations are supported by a recent study showing that vitamin E supplementation to old mice leads to increased IL-2 production only in naïve T cells (39)
.
The mechanisms behind the selective targeting of Th1 cytokine production and naïve T cells by vitamin E remain elusive. Hydrogen peroxide was reported to inhibit specifically the activity of memory/activated T cells (30) . Furthermore, it was shown that IL-10 production was particularly sensitive to oxidative stress. If this would occur also in patients with colorectal cancer, a more pronounced stimulatory effect on the memory/activated T cell subset and on IL-10 production would be expected as a result of the scavenging properties of vitamin E. Because this was not the case, the positive effect of vitamin E on Th1 cytokine production by naïve T cells, described here, may involve other mechanisms, including the previously described inhibition of prostaglandin production (32 , 44) or via a direct stimulatory effect on T cell function (39 , 48) . In the study of Adolfsson et al. (39) , it is suggested that the direct effect of vitamin E on T cells is a result of the enhanced IL-2 production in naïve T cells leading to proliferation and maturation of surrounding cells via an auto-paracrine loop.
The significance of IL-2 for cellular immunity is evident by its role in mediating clonal expansion of activated T cells (49)
. The induction of IL-2 production by activated T cells results in the up-regulation of high-affinity IL-2 receptors on T cells and, thus, in the responsiveness to IL-2 and progression through the cell cycle, as well as the differentiation of naïve T cells into effectors. IL-2 alone or in combination with other cytokines has, in various protocols against murine and human tumors, resulted in objective tumor regression and even in complete responses in a few patients (reviewed in Ref. 50
). The importance of IFN-
in relation to tumor immunity has been clearly demonstrated in STAT1 and IFN-
-receptor knockout mice. Mice that are deficient in IFN-
signaling components develop carcinogen-induced sarcomas at a higher frequency than do wild-type mice (51)
. Furthermore, the antitumor immunity is dependent on CD8+ T cells, which produce high amounts of IFN-
but no IL-4 and/or IL-5 (Tc1 cells; Ref. 52
). Tc1 cells, but not cells producing high amounts of IL-4 and/or IL-5 and low amounts of IFN-
(Tc2 cells), were capable of protecting against tumor challenges when adoptively transferred to syngeneic mice. These studies, together, support an active role of the immune system against tumors and suggest that IFN-
is one of the most important components in this process, in part by modulating the immunogenicity of the tumor cells (53)
.
Vitamin E supplementation was also shown to increase CD4:CD8 ratios. It was previously reported that colorectal cancer patients with advanced disease have reduced numbers of CD4+ T cells leading to a decreased CD4:CD8 ratio (12)
. In our study 5 of 12 patients had CD4:CD8 ratios below the reference interval. Analysis of these patients revealed that vitamin E resulted in statistically significant increases and almost normalized CD4:CD8 ratios (Fig. 6
; P < 0.05). CD4:CD8 ratios were, however, also increased significantly in patients with normal ratios before treatment, which indicated a generalized recruitment of T helper cells.
Apart from changes in CD4:CD8 ratios, no significant changes in subsets expressing other phenotypic markers, including CD62L, HLA-DR, and CD25, were observed (Data not shown). Thus, the stimulatory effect of vitamin E on Th1 cytokine production was not a result of an altered number of regulatory T cells (CD4+, CD25+), known to suppress T-cell function (54) .
Most work on the positive effects of vitamin E on T-cell functions have been focused on the reversal of immune senescence in aging humans (32 , 42) . We found no correlation between age and increased IL-2 production in our trial, which included patients from 47 to 74 years of age (median 66, years). Thus, our data demonstrates that Th1 cytokine production can be enhanced by vitamin E in patients with colorectal cancer regardless of their age. It remains to be seen whether these effects would also sustain over longer time intervals of vitamin E supplementation, as would be necessary if combined with other immune interventions, such as specific vaccination with tumor antigens.
In closing, our results suggest that enhancing lymphocyte functions by dietary supplementation with vitamin E could precede more specific immune interventions, which may be dependent on a functional Th1 response. Finally, increased Th1 responses and, thus, enhanced antitumor activity by the immune system may be one molecular explanation for a beneficial role of vitamin E as primary prevention against cancer.
| ACKNOWLEDGMENTS |
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| FOOTNOTES |
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1 Supported by grants from the Swedish Cancer Society, the Cancer Society of Stockholm, the King Gustaf V Jubilee Fund, a gene therapy grant from the Swedish Research Council (to R. K.), the Wallenberg Foundation, the Swedish Cancer Society, and the "Strategic Foundation." ![]()
2 To whom requests for reprints should be addressed, at Cancer Center Karolinska, R8:01, Karolinska Hospital, S-17176. Stockholm, Sweden. Phone: 46-8-51776857; Fax: 46-8-309195; E-mail: rolf.kiessling{at}mtc ki.se. ![]()
3 The abbreviations used are: PBL, peripheral blood lymphocyte; PMA, phorbol 12-myristate 13-acetate; PBMC, peripheral blood monocyte; RDA, recommended dietary allowance; mAb, monoclonal antibody; NK, natural killer; IL, interleukin; Th1, T helper 1. ![]()
Received 12/20/01; revised 3/ 1/02; accepted 3/ 4/02.
| REFERENCES |
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chain in peripheral T cells and natural killer cells in patients with cervical cancer. Clin. Cancer Res., 2: 1825-1828, 1996.[Abstract]
B activation in T lymphocytes of patients with renal cell carcinoma. J. Natl. Cancer Inst. (Bethesda), 91: 718-721, 1999.
B in T cells from a subset of renal cell carcinoma patients is mediated by inhibition of phosphorylation and degradation of the inhibitor, I
B
. Blood, 92: 1334-1341, 1998.
chain expression in peripheral blood lymphocytes of patients with head and neck cancer. Clin. Cancer Res., 5: 329-334, 1999.
chain in T cells at the tumor site correlates with poor survival in patients with oral carcinoma. Cancer Res., 58: 5344-5347, 1998.
chain expression and apoptosis in CD3+ peripheral blood T lymphocytes of patients with melanoma. Clin. Cancer Res., 7: 947s-957s, 2001.
-chain. Cancer Res., 59: 1422-1427, 1999.
B activation in T cells. J. Clin. Investig., 104: 769-776, 1999.[Medline]
molecules and inhibits tumor-specific T-cell- and natural killer cell-mediated cytotoxicity. Eur. J. Immunol., 26: 1308-1313, 1996.[Medline]
chain of T-cell receptor complex and antigen-specific T-cell responses. Proc. Natl. Acad. Sci. USA, 93: 13119-13124, 1996.
B activation. J. Immunol., 167: 2595-2601, 2001.
-tocopherol in cultured liver cell lines under oxidant stress. FEBS Lett., 508: 489-492, 2001.[CrossRef][Medline]
-tocopherol in human erythrocytes by intracellular ascorbic acid. Arch. Biochem. Biophys., 349: 281-289, 1998.[CrossRef][Medline]
-tocopherol-enriched HDL and erythrocytes: application to asymptomatic hypercholesterolemic men. Free Radic. Biol. Med., 28: 815-823, 2000.[CrossRef][Medline]
-tocopherol and ß-carotene: incidence and mortality in a controlled trial. J. Natl. Cancer Inst. (Bethesda), 90: 440-446, 1998.
and lymphocytes prevent primary tumour development and shape tumour immunogenicity. Nature (Lond.), 410: 1107-1111, 2001.[CrossRef][Medline]
-dependent tumor surveillance system in immunocompetent mice. Proc. Natl. Acad. Sci. USA, 95: 7556-7561, 1998.This article has been cited by other articles:
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