Suppression of manganese superoxide dismutase augments sensitivity to radiation, hyperthermia and doxorubicin in colon cancer cell lines by inducing apoptosis

Increased expression of manganese superoxide dismutase (Mn-SOD), one of the mitochondrial enzymes involved in the redox system, has been shown to diminish the cytotoxic effects of several anti-cancer modalities, including tumour necrosis factor-alpha, ionizing radiation, certain chemotherapeutic agents and hyperthermia. We asked if Mn-SOD is a potential target to augment the sensitivity of cancer cells to various anti-cancer treatments and for this we established stable Mn-SOD antisense RNA expressing cell clones from two human colon cancer cell lines, HCT116 (p53 wild-type) and DLD1 (p53 mutant-type). Suppression of Mn-SOD in HCT116 was accompanied by an increased sensitivity to radiation, hyperthermia and doxorubicin, as compared with findings in controls. The mitochondrial permeability transition, as measured by a decrease of the mitochondrial transmembrane potential was more intensely induced by radiation in HCT116 antisense clones than in the control, an event followed by a greater extent of DNA fragmentation. Apoptosis was also induced by hyperthermia more intensely in HCT116 antisense clones than in the control. On the other hand, DLD1 antisense clones did not exhibit any enhancement of sensitivity to any of these treatments. These data support the possibility that inhibition of Mn-SOD activity renders colon cancer cells with wild-type p53 susceptible to apoptosis induced by radiation, hyperthermia and selected anti-cancer drugs. Therefore, we suggest that Mn-SOD could be a target molecule to overcome the resistance to anti-cancer treatments in some colon cancer cells carrying wild-type p53.     

RNA干扰RelB基因对小鼠RM-1前列腺癌细胞株放射敏感性的影响及其机制

目的:探讨RNA干扰RelB基因对鼠RM-1前列腺癌细胞株放射敏感性的影响及其机制。方法:利用靶向RelB基因的慢病毒载体(pLentilox-sh-RelB),脂质体介导转染RM-1细胞后进行放射(2,4,6,和8Gy剂量)处理培养,分别采用RT-PCR、Western印迹法及流式细胞术等方法检测RelB的mRNA和蛋白表达,锰超氧化物歧化酶(Mn-SOD)活力及细胞放射敏感性的变化。结果:转染后放射处理培养,siRelB-RM-1组RelB的mRNA和蛋白表达水平明显低于siVector-RM-1组和nontrans-RM-1组(P<0.05);放射处理培养后siRelB-RM-1组细胞凋亡百分率明显高于siVector-RM-1组和nontrans-RM-1组(P<0.05);培养后siRelB-RM-1组细胞Mn-SOD活力下降,放射增敏比为5.13。结论:RNA干扰RelB基因可增强鼠RM-1前列腺癌细胞株放射后的放射敏感性,其机制可能与RNA干扰RelB基因,抑制细胞增殖,降低Mn-SOD活力和诱导凋亡有关。     

血液中血管内皮生长因子和锰超氧化物歧化酶检测对肺癌的意义

目的 :探讨血液中血管内皮生长因子 (VEGF)及锰超氧化物歧化酶 (Mn -SOD)水平与原发性肺癌的关系。方法 :检测了 5 8例原发性肺癌、38例肺良性疾病、2 5例健康人血液中VEGF含量和Mn -SOD活力。同时测定了 10例原发性肺癌治疗后血液中VEGF和Mn -SOD水平的变化并与治疗前作了对比观察。结果 :与健康人和肺良性疾病相比 ,原发性肺癌患者血液中VEGF含量、Mn -SOD活力均明显升高 (P <0 .0 1) ,VEGF、Mn -SOD的阳性检出率和诊断正确率分别是 86 .2 %、90 .1%和 79.3%、84 .3%。二者对各型肺癌均有较高的检出率 ,VEGF及Mn -SOD水平与肺癌病期进展有关。 10例肺癌患者VEGF及Mn -SOD水平治疗后显著下降 (P <0 .0 1)。结论 :肺癌外周血液中VEGF含量及Mn -SOD活力异常升高 ,可作为肺癌的诊断、鉴别诊断、临床分期及疗效监测的参考指标。     

Pharmacokinetic and anti-inflammatory properties in the rat of superoxide dismutases (Cu SODs and Mn SOD) from various species

The comparison of the anti-inflammatory properties (carrageenan paw edema in the rat) of exogenous Cu SODs from various species and human Mn SOD administered at doses corresponding to clinical schedules, shows that human and bovine Cu SOD are fully active, whereas rat Cu SOD and Mn SOD are inefficient. This difference does not correspond to the similarity of pharmacokinetic properties (blood levels, subcellar location in kidney cortex) of the Cu proteins or to the increased circulating life time of Mn SOD. The pharmacological activity of exogenous SOD is limited to heterologous Cu SODs in the rat. A similar problem may occur in man. The true mechanism of action Cu SOD remains to be elucidated.     

maspin、Mn-SOD表达与鼻咽癌组织放疗敏感相关性研究

目的 研究maspin及Mn-SOD在放射治疗鼻咽癌中的表达,探讨其在放射治疗鼻咽癌中的意义.方法 取60例2006年第1次入院放射治疗鼻咽癌,运用原位杂交方法检测放射治疗鼻咽癌中maspin及Mn-SOD mRNA的表达.结果 在放疗敏感及放疗抗拒鼻咽癌中,maspin mRNA中度及强阳性表达率分别为70.00％和42.50％,Mn-SOD mRNA中度及强阳性表达率分别为55.00％和40.00％,差异有统计学意义.在放疗抗拒鼻咽癌中,maspin及Mn-SOD mRNA中度及强阳性表达率均与T分期呈正相关,T3和T4期中表达率分别为63.16％和63.16％,T1和T2期中表达率分别为23.81％和19.05％.在有、无远处转移中,maspin mRNA中度及强阳性的表达率分别为72.73％和31.03％,Mn-SOD mRNA中度及强阳性表达率分别为81.82％和24.14％,差异有统计学意义.结论 maspin、Mn-SOD参与了放射抗拒鼻咽癌的发展.     

磷脂酰肌醇3激酶-蛋白激酶B-叉头框蛋白信号通路在盆腔脏器脱垂中的表达

目的探讨磷脂酰肌醇3激酶(phosphatidylinositol 3 kinase,PI3K)-蛋白激酶B(protein kinase B,Akt)-叉头框蛋白(forkhead box O1,FOXO1)信号通路在盆腔脏器脱垂(pelvic organ prolapse,POP)中的表达及其在POP中的发病机制。方法选取2013年1月至2015年1月因POPⅢ度、Ⅳ度于武汉大学人民医院行全子宫切除术的患者20例(POP组)和同期因其他良性妇科疾病行全子宫切除术的患者20例(对照组),采用蛋白质免疫印记检测骶韧带组织中Akt、磷酸化蛋白激酶B(phosphorylation protein kinase B,p-Akt)、FOXO1、磷酸化(phosphorylation,p-)FOXO1、谷胱甘肽过氧化物酶(glutathione peroxidase1,GPX1)、锰超氧化物歧化酶(manganesesuperoxidedismutase,Mn-SOD)蛋白表达情况。结果 POP组较对照组,骶韧带组织中p-Akt/Akt、p-FOXO1/FOXO1表达比例明显上调,抗氧化蛋白GPX1、Mn-SOD表达下调。结论POP组织中PI3K-Akt-FOXO1信号通路被激活,并下调抗氧化蛋白GPX1、Mn-SOD表达,这一分子机制可能参与POP发生发展。     

Metabolic oxidative stress induced by a combination of 2-DG and 6-AN enhances radiation damage selectively in malignant cells via non-coordinated expression of antioxidant enzymes

Our earlier studies have shown that simultaneous inhibition of glycolysis and pentose phosphate pathway using 2-deoxy-d-glucose (2-DG, an inhibitor of glycolysis) and 6-aminonicotinamide (6-AN, an inhibitor of pentose phosphate pathway) lead to metabolic oxidative stress (MOS), resulting in radiosensitization in malignant cells. Present study was carried out to investigate the effects of 2-DG and 6-AN on intricately regulated endogenous antioxidant defense against MOS during radiosensitization by this combination. Two human tumor cell lines {Head and Neck Squamous carcinoma (KB) and Glioma (BMG-1)} and one non-malignantly transformed cell line (human embryonic kidney, HEK) were used in this study. The presence of 2-DG and 6-AN (added just before irradiation) for 4 h, significantly decreased the clonogenicity and metabolic viability of KB and BMG-1 cell lines, while no significant change was seen in HEK cells. Accumulation of ROS was observed only in malignant cell lines, which displayed a compromised redox status evident from enhanced NADP⁺/NADPH and GSSG/GSH ratios and a concomitant decrease in glutathione reductase level and activity at 24 h following treatment. The levels and activities of Cu, Zn-SOD and Mn-SOD increased with MOS and were accompanied by a decreased GPx and unaltered catalase activity and level. These results suggest that non-coordinated expression of antioxidant defense, besides compromised redox status, led to selective radiosensitization in the malignant cells.     

Resveratrol accelerates wound healing by attenuating oxidative stress-induced impairment of cell proliferation and migration

BackgroundImpaired wound healing, which is due to various external and internal factors that are involved in wound pathophysiology, leads to high rates of morbidity and mortality worldwide. Oxidative stress injury is an important factor that affects wound healing by changing the whole healing process. So, resveratrol, a dietary fruits polyphenol, which is known for its antioxidant properties, maybe the candidate to accelerate the wound-healing process.MethodsThe Human Umbilical Vein Endothelial Cells (HUVECs) was used for in vitro experiments to evaluate the effect of resveratrol on hyperglycemia-induced gene expression, oxidative stress and cell proliferation. The diabetic rat model was used to evaluate the effect of resveratrol on cutaneous burn injury healing process.ResultsIncreases in H₂O₂ decreased cell viability with the 0?800 μM concentration range, and resveratrol could protect HUVECs against H₂O₂-induced injury. The scratched wound closed rate in H₂O₂ group was significantly smaller than the Control group (p < 0.05) and Resveratrol + H₂O₂ group (p < 0.05). The fluorescence intensity of ROS was lower in Control and Resveratrol + H₂O₂ groups than H₂O₂ group. Correspondingly, compared to H₂O₂ group, the expressions of Mn-SOD and nuclear Nrf2 (N-Nrf2) was up-regulated in Resveratrol + H₂O₂ group (p < 0.05). In vivo, compared with the saline group, using resveratrol could significantly accelerate wound healing of rats on Day 14 (p < 0.05) and make the regenerated skin structure more complete and inflammatory response lower. Moreover, the expressions of Mn-SOD was significantly up-regulated after using resveratrol.ConclusionsResveratrol has the positive effects on promoting the acceleration and quality of skin wound healing, which maybe at least in part caused by the up-regulation of nuclear Nrf2 and Mn-SOD that subsequently attenuated oxidative stress.     

TNFAIP3､Mn-SOD在放射治疗鼻咽癌中的意义

目的 :研究肿瘤坏死因子α诱导蛋白3(tumor necrosis factor alpha induced protein 3,TNFAIP3)、锰超氧化物歧化酶(Manganese superoxide dismutase,Mn-SOD)m RNA在放射治疗后鼻咽癌中的表达,探讨其在鼻咽癌放射治疗中的意义。方法 :运用原位杂交方法检测放射治疗后鼻咽癌中TNFAIP3及Mn-SOD m RNA的表达。结果:TNFAIP3 m RNA中度及强阳性表达率在放疗敏感鼻咽癌中为15.00%,在放疗抗拒鼻咽癌中为45.00%;Mn-SOD m RNA中度及强阳性表达率在放疗敏感鼻咽癌中为55.00%,在放疗抗拒鼻咽癌中为40.00%,差异均有统计学意义(P均<0.05)。在放疗抗拒鼻咽癌中,TNFAIP3 m RNA中度及强阳性表达率与TNM分期呈正相关,Ⅲ~Ⅳ期表达率为48.28%,Ⅰ~Ⅱ期表达率为36.36%,Mn-SOD m RNA中度及强阳性表达率与T分期呈正相关,T3~T4期中表达率为63.16%,T1~T2期中表达率为19.05%;TNFAIP3 m RNA中度及强阳性表达率在有远处转移的放疗抗拒鼻咽癌中为81.81%,在无远处转移的放疗抗拒鼻咽癌中为31.03%,Mn-SOD m RNA中度及强阳性表达率在有远处转移的放疗抗拒鼻咽癌中为81.82%,在无远处转移的放疗抗拒鼻咽癌中为24.14%,差异均有统计学意义(P均<0.05)。结论:TNFAIP3参与了放疗抗拒鼻咽癌的发生、发展;Mn-SOD能增加鼻咽癌的放射敏感性,增强放疗鼻咽癌的抗氧化作用。     

Long term treatment with ACE inhibitor enalapril decreases body weight gain and increases life span in rats

Renin-angiotensin system is involved in homeostasis processes linked to renal and cardiovascular system and recently has been linked to metabolic syndrome. We analyzed the influence of long term angiotensin I converting enzyme (ACE) inhibitor enalapril treatment in normotensive adult Wistar rats fed with standard or palatable hyperlipidic diets. Our results show that long term enalapril treatment decreases absolute food intake, serum leptin concentration and body weight gain. Moreover, in adipose tissue, enalapril treatment led to decreased ACE activity, enhanced the expression of peroxisome proliferator activated receptor gamma, adiponectin, hormone-sensitive lipase, fatty acid synthase, catalase and superoxide dismutase resulting in prolonged life span. On the other hand, the ACE inhibitor was not able to improve the transport of leptin through the blood brain barrier or to alter the sensitivity of this hormone in the central nervous system. The effect of enalapril in decreasing body weight gain was also observed in older rats. In summary, these results extend our previous findings and corroborate data from the literature regarding the beneficial metabolic effects of enalapril and show for the first time that this ACE inhibitor prolongs life span in rats also fed with palatable hyperlipidic diet, an action probably correlated with adipose tissue metabolic modulation and body weight reduction.