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Query: UNIPROT:P04179 (
MnSOD
)
2,777
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Intracellular superoxide (O(2)*- was manipulated in M14 melanoma cells by overexpression or repression of Cu/Zn SOD using a tetracycline-inducible expression system. Scavenging intracellular O(2)*- increased
tumor
cell sensitivity to daunorubicin, etoposide, and pMC540, whereas expression of the antisense
SOD mRNA
significantly decreased cell sensitivity to drug treatment. Whereas Cu/Zn SOD overexpressing cells exhibited higher activation of the executioner caspase 3 upon drug exposure, caspase 3 activation was significantly lower when Cu/Zn SOD was repressed by antisense expression. These data show that intracellular O(2)*- regulates
tumor
cell response to drug-induced cell death via a direct or indirect effect on the caspase activation pathway.
...
PMID:Superoxide anion inhibits drug-induced tumor cell death. 1052 62
We have shown that the loss of p53 function contributed to resistance of
tumor
cells to TNF-induced cytotoxicity. In the present study, we evaluated the effect of wild-type p53 (wt-p53) expression on TNF sensitivity, by introducing wt-p53 into MCF7/Adr cells in which p53 was deleted, via a recombinant adenovirus encoding p53 (Ad-p53). Our results indicate that infection with Ad-p53 (50-100 viral particles per cell) resulted in pronounced cytotoxicity, whereas infection with 10 viral particles per cell, which was weakly toxic for the MCF7/Adr cells, sensitized these cells to TNF-induced cell death. Moreover, expression of wt-p53 in MCF7/Adr cells induced the production of reactive oxygen intermediates (ROIs) and caused glutathione (GSH) depletion, indicating disturbances in the cellular redox state. Additional treatment of cells with the anti-oxidant and glutathione (GSH) precursor N-acetylcysteine (NAC) resulted in inhibition of p53-induced ROIs production and in partial restoration of intracellular GSH levels, which was associated with the ability of NAC to inhibit p53-modulated TNF-induced cytotoxicity. Interestingly, Ad-p53 was able to inhibit TNF-induced
MnSOD
mRNA expression in MCF7/Adr cells, which might contribute to the sensitization of cells to the cytotoxic action of TNF. Taken together, our data strongly suggest that wt-p53 expression sensitizes TNF-resistant MCF7 cells with p53 deletion to TNF-induced cell death by a pathway that is dependent on ROIs production.
...
PMID:Adenovirus-mediated wild-type-p53-gene expression sensitizes TNF-resistant tumor cells to TNF-induced cytotoxicity by altering the cellular redox state. 1058 90
To determine whether intratracheal (IT) lung protective manganese superoxide-plasmid/liposomes (MnSOD-PL) complex provided 'bystander' protection of thoracic tumors, mice with orthotopic Lewis lung carcinoma-bacterial beta-galactosidase gene (3LL-LacZ) were studied. There was no significant difference in irradiation survival of 3LL-LacZ cells irradiated, then cocultured with
MnSOD
-PL-treated compared with control lung cells (D0 2.022 and 2.153, respectively), or when irradiation was delivered 24 h after coculture (D0 0.934 and 0.907, respectively).
Tumor
-bearing control mice showed 50% survival at 18 days and 10% survival at 21 days. Mice receiving liposomes with no insert or LacZ-PL complex plus 18 Gy had 50% survival at 22 days, and a 20% and 30% survival at day 50, respectively. Mice receiving
MnSOD
-PL complex followed by 18 Gy showed prolonged survival of 45% at 50 days after irradiation (P < 0.001). Nested RT-PCR assay for the human
MnSOD
transgene demonstrated expression at 24 h in normal lung, but not in orthotopic tumors. Decreased irradiation induction of TGF-beta1, TGF-beta2, TGF-beta3, MIF, TNF-alpha, and IL-1 at 24 h was detected in lungs, but not orthotopic tumors from
MnSOD
-PL-injected mice (P < 0.001). Thus, pulmonary radioprotective
MnSOD
-PL therapy does not provide detectable 'bystander' protection to thoracic tumors.
...
PMID:Intratracheal injection of manganese superoxide dismutase (MnSOD) plasmid/liposomes protects normal lung but not orthotopic tumors from irradiation. 1087 49
Cancer cells are in general low in the enzymatic activities of both manganese-containing (
MnSOD
) and copper- and zinc-containing superoxide dismutase. We have hypothesized that part of the
tumor
cell phenotype is due to this loss of enzymatic activity. To test this hypothesis, we have overexpressed
MnSOD
via plasmid and adenovirus transfection in various cancer cell types and have shown
tumor
suppression. This
tumor
suppression is via a noncytotoxic mechanism and probably occurs due to cell-cycle perturbations. We have also shown that
MnSOD
overexpression causes the anticancer drug 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) to have increased cytotoxicity. Our hypothesis for the mechanism of action of this combination is that overexpression of
MnSOD
leads to increased peroxide levels and that BCNU inhibits peroxide removal. We currently are investigating the use of adenovirus
MnSOD
plus BCNU in the treatment of cancer. Results thus far are consistent with the idea that we can use the alterations in antioxidant enzymes observed in cancer cells to therapeutic advantage.
...
PMID:Anticancer therapy by overexpression of superoxide dismutase. 1149 57
To test the hypothesis that carcinogen exposure and oxidative stress are involved in pancreatic carcinogenesis in susceptible individuals, aromatic DNA adducts and 8-hydroxyguanosine (8-OH-dG) were measured by (32)P-postlabeling and HPLC-EC, respectively, in 31 pancreatic tumors and 13 normal tissues adjacent to the
tumor
from patients with pancreatic cancer. Normal pancreatic tissues from 24 organ donors, from six patients with non-pancreatic cancers, and from five patients with chronic pancreatitis served as controls. It was found that tissue samples from patients with pancreatic cancer had significantly higher levels of both aromatic DNA adducts and 8-OH-dG compared with control samples. The mean (+/-S.D.) levels of aromatic DNA adducts were 101.8+/-74.6, 26.9+/-26.6, and 11.2+/-6.6 per 10(9) nucleotides in adjacent tissues, tumors, and controls, respectively. The mean (+/-S.D.) levels of 8-OH-dG were 11.9+/-9.6, 10.8+/-10.6, and 6.7+/-4.6 per 10(5) nucleotides in adjacent tissues, tumors, and controls, respectively. Polymorphisms of the CYP1A1, CYP2E1, NAT1, NAT2, GSTM1,
MnSOD
, and hOGG1 genes were determined in these patients. The level of aromatic DNA adducts was significantly associated with polymorphism of the CYP1A1 gene. No significant correlation was found between the level of 8-OH-dG and the
MnSOD
, GSTM1, and hOGG1 polymorphisms. However, one novel polymorphism/mutation of the hOGG1 gene was found in a pancreatic
tumor
. Mutation at codon 12 of the K-ras gene was found in 25 (81%) of 31 pancreatic tumors, including three G-to-A transitions and 22 G-to-T transversions. Patients with the G-to-T mutation had a significantly higher level of aromatic DNA adducts than those with G-to-A or wild-type codon (P=0.02). On the other hand, the K-ras mutation profile was not related to the level of 8-OH-dG. Given the limitation of sample size, these preliminary data lend further support the hypothesis that carcinogen exposure and oxidative stress are involved in pancreatic carcinogenesis.
...
PMID:DNA adducts, genetic polymorphisms, and K-ras mutation in human pancreatic cancer. 1171 88
ROIs and their scavengers are associated with apoptosis induction by anticancer drugs and gamma-rays, but the details have not been clarified. We examined the effect of transfection of
Mn-SOD
antisense on apoptosis by 5-FU, PLM, CDDP and gamma-rays using nu/nu mice. After inoculation of
Mn-SOD
antisense-transfected SCC cells into the subcutis of each mouse's back, they slowly multiplied to form tumors sized 1,460 +/- 70 mm(3) at day 60, while control vector-transfected SCC cells rapidly multiplied, with a mean
tumor
size of 2,330 +/- 220 mm(3). Inversely, mice in the
Mn-SOD
antisense group survived longer (mean survival duration 94.4 +/- 12.7 days) compared to those in the empty vector group (67.3 +/- 6.8 days). After treatment with 5-FU (5 microg/day), PLM (50 microg/day), CDDP (10 microg/day) and gamma-rays (2 Gy/day), mean survival times were largely prolonged, to 126.3 +/- 22.7, 123.0 +/- 22.1, 136.3 +/- 24.0 and 143.0 +/- 20.8 days, respectively, while mean survival times in the empty vector group were 91.7 +/- 14.8, 85.7 +/- 13.3, 97.5 +/- 16.0 and 100.7 +/- 17.1 days, respectively. Immunohistologically, tumors in the
Mn-SOD
antisense group revealed additional nick end-labeled cells compared to those in the empty vector group. In comparison, strong expression of Bax, Bak and p21(waf1/cip1) and suppressed expression of Bcl-2, Bcl-X(L) and COX-2 were observed in the
Mn-SOD
antisense group and the expression pattern of these proteins was the inverse in the empty vector group. The increased expression of these proapoptotic proteins appeared to be p53-independent because p53 protein expression was not increased in the antisense group. These immunohistologic results were supported by Western blotting of each protein. In conclusion,
Mn-SOD
antisense transfection is advantageous for apoptosis induction of SCC cells by anticancer drugs and gamma-rays through induction of proapoptotic Bcl-2 family proteins and suppression of antiapoptotic protein expression.
...
PMID:Mn-SOD antisense upregulates in vivo apoptosis of squamous cell carcinoma cells by anticancer drugs and gamma-rays regulating expression of the BCL-2 family proteins, COX-2 and p21. 1174 42
SA-NH mouse sarcoma cells were grown to confluence and then exposed to either 40 microM or 4 mM of WR-1065, i.e. the active thiol form of amifostine, for 30 min and then washed. Total RNA and protein were isolated at various times up to 24 h after exposure. Both concentrations of WR-1065 were equally effective in affecting Sod2 (also known as
MnSOD
) gene expression and protein levels. Northern blot analysis using a mouse cDNA probe revealed three Sod2 transcripts of 1, 4 and 6 kb. Expression of both the 4- and 6-kb transcripts increased by 20 and 60%, respectively, and remained elevated over a period of 4 to 20 h. Sod2 protein levels, as determined by Western blot analysis, increased 15-fold over background control levels over the same interval. Sod2 protein was evaluated using activity gels and was found to be active. SA-NH cells were irradiated with X rays either in the presence of 40 microM or 4 mM WR-1065 or 24 h later after its removal, when Sod2 protein levels were most elevated. No protection was observed for cells irradiated in the presence of 40 microM WR-1065. In contrast, survival after a dose of 2 Gy was elevated 1.27-, 1.14- and 1.20-fold in SA-NH cells irradiated in the presence of 4 mM WR-1065 or 24 h after exposure of the cells to 40 microM and 4 mM WR-1065, respectively. The increased survival levels observed 24 h after exposure to WR-1065 represents a delayed radioprotective effect of WR-1065 and corresponds to the time at which Sod2 protein levels are most elevated. These data demonstrate a novel mechanism for radioprotection by WR-1065 and suggest a new potential concern regarding the issue of
tumor
protection.
...
PMID:Delayed cytoprotection after enhancement of Sod2 (MnSOD) gene expression in SA-NH mouse sarcoma cells exposed to WR-1065, the active metabolite of amifostine. 1207 9
In adrenal glands, oxidative free radicals are synthesized in the course of hormonal production, and enzyme superoxide dismutase (SOD) is considered to scavenge these harmful superoxide radicals and, subsequently, to protect the cells. We studied immunohistochemical localization of Mn (manganese)-SOD and Cu,Zn (copper-zinc)-SOD in human adrenal and its disorders from fetus to adult obtained from autopsy or surgery in order to examine the possible biological significance of these two enzymes. In fetal adrenal (n = 4), Cu,Zn-SOD and
Mn-SOD
were detected only in the fetal cortex. In adrenal glands from children (n = 21) to adults (n = 15),
Mn-SOD
immunoreactivity was exclusively detected in adrenal medulla, whereas Cu,Zn-SOD immunoreactivity was present only in adrenocortical parenchymal cells, weakly in the zona glomerulosa, and markedly in the zona reticularis. There were no differences in relative immunointensity and/or patterns of immunolocalization of these two SODs among different age groups. Both Cu,Zn-SOD and
Mn-SOD
immunoreactivity were detected in compact
tumor
cells of adrenocortical adenoma (n = 16). Marked immunoreactivity of both Cu,Zn-SOD and
Mn-SOD
was detected in adrenocortical carcinoma (n = 11) and pheochromocytoma (n = 5). These results indicate that Cu,Zn-SOD and Mu-SOD may play different roles as a scavenger or antioxidants in normal human adrenal glands, i.e., Cu,Zn-SOD as a scavenger of toxic superoxide radicals generated during steroidogenesis and
Mn-SOD
during catecholamine production. Cu,Zn-SOD and
Mn-SOD
immunoreactivities detected in adrenal neoplasms are also considered to represent altered expression of these enzymes associated with neoplastic transformation, as reported in other human malignancies.
...
PMID:Superoxide Dismutase in Human Adrenal and its Disorders: A Correlation with Development and Neoplastic Changes. 1211 69
Photodynamic therapy (PDT), a promising therapeutic modality for the management of solid tumors, is a two-phase treatment consisting of a photosensitizer and visible light. Increasing evidence indicates that
tumor
cells in regions exposed to sublethal doses of PDT can respond by rescue responses that lead to insufficient cell death. We decided to examine the role of superoxide dismutases (SODs) in the effectiveness of PDT and to investigate whether 2-methoxyestradiol (2-MeOE(2)), an inhibitor of SODs, is capable of potentiating the antitumor effects of this treatment regimen. In the initial experiment we observed that PDT induced the expression of
MnSOD
but not Cu,Zn-SOD in cancer cells. Pretreatment of cancer cells with a cell-permeable SOD mimetic, Mn(II)-tetrakis(4-benzoic acid)porphyrin chloride, and transient transfection with the
MnSOD
gene resulted in a decreased effectiveness of PDT. Inhibition of SOD activity in
tumor
cells by preincubation with 2-MeOE(2) produced synergistic antitumor effects when combined with PDT in 3 murine and 5 human
tumor
cell lines. The combination treatment was also effective in vivo producing retardation of the tumor growth and prolongation of the survival of
tumor
-bearing mice. We conclude that inhibition of
MnSOD
activity by 2-MeOE(2) is an effective treatment modality capable of potentiating the antitumor effectiveness of PDT.
...
PMID:Antitumor effects of photodynamic therapy are potentiated by 2-methoxyestradiol. A superoxide dismutase inhibitor. 1240 96
BACKGROUND: d-alpha-tocopherol is a naturally occurring form of vitamin E not previously known to have antitumor activity. Synthetic vitamin E (sE) is a commonly used dietary supplement consisting of a mixture of d-alpha-tocopherol and 7 equimolar stereoisomers. To test for antilipid peroxidation and for antitumor activity of sE supplementation, two groups of nude mice bearing a MDA-MB 231 human breast cancer
tumor
were fed an AIN-76 diet, one with and one without an additional 2000 IU/kg dry food (equivalent to 900 mg of all-rac-alpha-tocopherol or sE). This provided an intake of about 200 mg/kg body weight per day. The mice were killed at either 2 or 6 weeks after the start of dietary intervention. During necropsy,
tumor
and host tissues were excised for histology and for biochemical analyses. RESULTS:
Tumor
growth was significantly reduced by 6 weeks of sE supplementation. Thiobarbituric acid reactive substances, an indicator of lipid peroxidation, were suppressed in
tumor
and in host tissues in sE supplemented mice. In the sE treated mice, the fatty acid composition of microsomal and mitochondrial membranes of
tumor
and host tissues had proportionately less linoleic acid (n-6 C 18-2), similar levels of arachidonic acid (n-6 C 20-4), but more docosahexanoic acid (n-3 C 22-6). The sE supplementation had no significant effect on blood counts or on intestinal histology but gave some evidence of cardiac toxicity as judged by myocyte vacuoles and by an indicator of oxidative stress (increased ratio of Mn
SOD mRNA
over GPX1 mRNA). CONCLUSIONS: At least one of the stereoisomers in sE has antitumor activity. Synthetic vitamin E appears to preferentially stabilize membrane fatty acids with more double bonds in the acyl chain. Although sE suppressed tumor growth and lipid peroxidation, it may have side-effects in the heart.
...
PMID:High dietary level of synthetic vitamin E on lipid peroxidation, membrane fatty acid composition and cytotoxicity in breast cancer xenograft and in mouse host tissue. 1269 31
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