DHA在人乳腺癌中对阿霉素细胞毒活性的影响与脂质过氧化作用的关系

目的　探讨廿二碳六烯酸 (DHA)影响阿霉素 (ADM)对人乳腺癌DMA MB 435s细胞毒活性的机理是否通过DHA的脂质过氧化作用。方法　在培养的人乳腺癌DMA MB 435s细胞株中加入不同配伍的细胞毒药物、多不饱和脂肪酸 (PUFAs)、前氧化剂VitC和VitK3混合物及抗氧化剂VitE等 ,在细胞的抽提物中以TBA法每 2 4小时测定脂质过氧化产物丙二醛 (MDA)及用亚硝酸盐分光光度法测定一氧化氮 (NO)的含量 ,并作出MDA、NO含量与细胞毒性间的剂量 -效应相关直线。结果　从细胞培养的第三天开始 ,出现明显的细胞活力变化 ,同时伴有脂质过氧化物 (MDA)水平的增加及NO含量的降低。细胞抽提物中MDA及NO含量与细胞毒性之间存在直线相关关系。结论　DHA能明显增加ADM对MDA MB 435s细胞株的细胞毒活性 ,机理之一是DHA增强了瘤细胞内的脂质过氧化作用。     

DAC－树脂血液灌流对肝血管输注阿霉素心肌脂质过氧化的影响

ＤＡＣ－树脂ＤＨＰ与肝血管持续输注ＡＤＲ联合应用结果显示，体内心肌丙二醛（ＭＤＡ）含量与ＡＤＲ投入量呈正相关（ｒ＝０．８９７７），ＤＡＣ－树脂ＤＨＰ较对照灌流组能明显降低ＡＤＲ（５ｍｇ／ｋｇ和１０ｍｇ／ｋｇ）急性期心肌ＭＤＡ含量，分别为０．４０５４±０．０４９７对０．７１２９±０．０１６３１ｎｍｏｌ／ｍｇＣｐｒｏｔ（Ｐ＜０．００５）和０．６８９２±０．０９６８对０．９９２２±０．２０７０ｎｍｏｌ／ｍｇＣｐｒｏｔ（Ｐ＜０．０１）；也能显著降低ＡＤＲ（５ｍｇ／ｋｇ）亚急性期（第８天）心肌ＭＤＡ含量（０．５５０４±０．０６２８对０．７４５２±０．０６１２ｎｍｏｌ／ｍｇＣｐｒｏｔ；Ｐ＜０．００５）。表明ＡＤＲ心肌脂质过氧化具有剂量和时间依赖性，ＤＡＣ－树脂ＤＨＰ能明显降低急性期和亚急性期ＡＤＲ刺激产生自由基导致心肌膜结构脂质过氧化的程度，可认为能减轻ＡＤＲ所致心肌急性期和亚急性期的损害程度。     

电离辐射后阿霉素对大肠癌HCT-8细胞毒活性的影响

[目的]研究不同剂量电离辐射后阿霉素对大肠癌细胞株HCT-8细胞毒活性的影响,旨在探讨逆转大肠癌多药耐药性的方法。[方法]体外培养大肠癌细胞株HCT-8,以400ng/ml阿霉素做为实验模型刺激浓度。实验模型分为以下5组:对照组;大剂量组(2Gy);0.05Gy 2Gy组;0.1Gy 2Gy组;0.2Gy 2Gy组。采用MTT法测定给予阿霉素后大肠癌细胞株HCT-8毒活性。[结果]与假照射组相比,2Gy照射组及0.2Gy 2Gy组照射后HCT-8细胞存活率明显降低(P<0.05),先给予低剂量照射(0.05Gy,0.1Gy)后,再给予大剂量照射,HCT-8细胞存活率降低更明显(P<0.01)。与单纯2Gy照射组比较,0.05Gy 2Gy组及0.1Gy 2Gy组HCT-8细胞生存率明显降低(P<0.05)。[结论]先给予低剂量照射后,再给予大剂量照射,阿霉素对HCT-8细胞存活率明显降低,提示低剂量照射可增强大肠癌细胞株对阿霉素的敏感性。     

互隔交链孢酚单甲醚对脂质过氧化的影响

本文观察了互隔交链隔孢霉的产物之一－－交链孢酚单甲醚（ＡＭＥ）对小鼠体内脂质过氧化的影响。给小鼠腹腔内注射不同浓度的ＡＭＥ，结果表明，低浓度的ＡＭＥ（５４．５ｍｇ／ｋｇ体重）降低了脂质过氧化物的生成，随着ＡＭＥ浓度的增加，脂质过氧化物的含量显著增加。     

二甲基亚硝胺对鼠体脂质过氧化的影响

目的：亚硝胺是四大食品污染物之一，大量流行病学资料显示人类的食管癌、古癌和胃癌等与之有关，基致癌机理，尚无成熟看法，有人提出可能与自由基反应有关，为探讨亚硝胺的致癌机制及与自由基的关系。方法：本研究用不同剂量的二甲基亚硝胺观察其对鼠体脂质过氧化反应的影响。结果：二甲基亚硝胺可使大鼠血清和肝肾ＭＤＡ产生增加；血红细胞的肝肾ＳＯＤ活性下降；全血ＧＳＨ－Ｐｘ活性下降。结论：自由基和脂质过氧休反应可能是二     

甲基丙烯酸环氧丙酯对大鼠脂质过氧化与抗氧化作用的研究

甲基丙烯酸环氧丙酯（Glycidylmethacrylate,GMA）系一种高强度粘合剂的单体,其结构式为：在军事和民用工业中有其广泛用途。本课题组以往研究表明：GMA能诱发鼠伤寒抄门氏菌碱基置换型突变,并能诱发小鼠骨髓多染红细胞微核率升高、小鼠精子畸变和人淋巴细胞程序外DNA合成,从而证明GMA是一个新诱变剂。进一步研究发现,在体外GMA也可诱导动物和人细胞恶性转化【’一则Z转化细胞能在裸鼠体内形成分化程度较低的纤维瘤,这些结果均表明GMA对生物体具有致癌的潜在危险性。本试验拟观察GMA在大鼠亚慢性毒性实验过程中对动物的影响…     

维生素B6对实验性肝癌大鼠脂质过氧化的影响

目的：探讨维生素Ｂ６对大鼠实验性肝癌形成过程中脂质过氧化的影响。方法：雄性ＳＤ大鼠随机分为三组，正常组大鼠喂普通饲料；ＤＡＢ组大鼠饲料中含０．０６％３’－甲基－４－双甲氨基偶氮苯（３‘－ＭｅＤＡＢ），１０周后改喂普遍饲料；Ｂ６组大鼠饲料中除含有０．０６％，３’－ＭｅＤＡＢ外，另加Ｖｉｔ，Ｂ６８００ｍｇ／ｋｇ，１０周后停喂３‘－ＭｅＤＡＢ，改喂加入８００ｍｇ／ｋｇ，ｖｉｔ，Ｂ６的普通饲料。     

AX2对鼠肝脂质过氧化及谷胱甘肽过氧化物酶的影响

近年来,霉菌及其毒素与肿瘤的关系日益受关注,互隔交链孢霉是从林县粮食中分离的,对粮食的污染程度,高发区与低发区差异显著。用该霉菌发霉食物喂大鼠,诱发了前胃和食管乳头状瘤及前胃癌。人们认为化学致癌物的致癌过程与自由基有关。而谷胱甘肽过氧化物酶(GSHPX)则是清除自由基的酶类之一。     

煤焦油烟对作业工人血中超氧化物歧化酶活性及脂质过氧化产物含量影响的研究

本文通过对武钢焦比厂４０名炼焦作业工人和４０名健康人血中ＳＯＤ和ＬＰＯ水平进行研究，结果表明炼焦工人血中ＳＯＤ活性明显低于对照组．差异非常显著（Ｐ＜０．０ｌ）．血清中ＬＰＯ含量明显高于对照组，差异极显著（Ｐ＜０．０ｌ）。同时分析了作业工人的工龄和烟酒嗜好与ＳＯＤ及ＬＰＯ之间的关系．结果都未见有明显差异。     

Opposing effects of dietary n-3 and n-6 fatty acids on mammary carcinogenesis: The Singapore Chinese Health Study

We investigated the effects of individual fatty acids on breast cancer in a prospective study of 35,298 Singapore Chinese women aged 45-74 years, who were enrolled during April 1993 to December 1998 (The Singapore Chinese Health Study). At recruitment, each study subject was administered, in-person, a validated, semiquantitative food frequency questionnaire consisting of 165 food and beverage items. As of December 31, 2000, 314 incident cases of breast cancer had occurred. We used the Cox regression methods to examine individual fatty acids in relation to breast cancer risk, with adjustment for age at baseline interview, year of interview, dialect group, level of education, daily alcohol drinking, number of live births, age when menstrual periods became regular, and family history of breast cancer. Consumption of saturated, monounsaturated or polyunsaturated fat overall was unrelated to risk. On the other hand, high levels of dietary n-3 fatty acids from fish/shellfish (marine n-3 fatty acids) were significantly associated with reduced risk. Relative to the lowest quartile of intake, individuals in the higher three quartiles exhibited a 26% reduction in risk (relative risk (RR)=0.74, 95% confidence interval (CI)=0.58, 0.94)); RRs were similar across the top three quartiles of intake (0.75, 0.75, 0.72, respectively). Overall, there was no association between n-6 fatty acids and breast cancer risk. However, among subjects who consumed low levels of marine n-3 fatty acids (lowest quartile of intake), a statistically significant increase in risk was observed in individuals belonging to the highest vs the lowest quartile of n-6 fatty acid consumption (RR=1.87, 95% CI=1.06-3.27); the corresponding RR for advanced breast cancer was 2.45 (95% CI=1.20-4.97, P for trend=0.01). To our knowledge, these are the first prospective findings linking the intake of marine n-3 fatty acids to breast cancer protection.     

5-Fu和α干扰素抗肿瘤血管形成协同效应的实验研究

目的: 研究fat-1基因在人乳腺癌细胞内的表达、功能及其对乳腺癌细胞增殖的影响.方法: 把fat-1 基因插入到腺病毒的穿梭载体中,与骨架载体同源重组,构建腺病毒重组载体 (Ad.GFP.fat1),将通过包装细胞系(293)产生的腺病毒感染人乳腺癌株QMR2细胞.提取细胞的总RNA,以fat-1的反义mRNA 作探针,用Northern Blot检测fat-1 基因在人乳腺癌株QMR2细胞内的表达.流式细胞仪分析n-3脂肪酸脱氢酶对人乳腺癌株QMR2细胞增殖的影响.气象色谱仪分析n-3脂肪酸脱氢酶对人乳腺癌株QMR2细胞的n-6 PUFAs/n-3 PUFAs含量影响.结果: fat-1 基因在人乳腺癌株QMR2细胞中能有效异源表达,2 d后检测到fat-1mRNA的条带.fat-1基因抑制了人乳腺癌株QMR2细胞的增殖,降低了20%(P<0.05);同时降低了人乳腺癌株QMR2细胞n-6 PUFAs/n-3 PUFAs含量降低.结论: 腺病毒介导的fat-1 基因能在人乳腺癌株QMR2细胞内有效异源表达,且抑制人乳腺癌株QMR2细胞的增殖.     

Intake of n-3 and n-6 polyunsaturated fatty acids and development of colorectal cancer by subsite: Japan Public Health Center-based prospective study

To date, epidemiologic studies investigating intake of n-3 and n-6 polyunsaturated fatty acids and risk of colorectal cancer are limited, and results remain inconsistent. This is the first prospective study to show the association by subsite (proximal colon, distal colon, rectum). To clarify the role of n-3 and n-6 polyunsaturated fatty acids intake in colon carcinogenesis, we conducted a large, population-based prospective study, characterized by high fish consumption and a wide range of n-3 polyunsaturated fatty acids intakes. Subjects were followed from response to a lifestyle questionnaire in 1995-1999 through 2006. During 827,833 person-years of follow-up (average 9.3 years), we identified 1,268 new colorectal cancer cases (521 colon and 253 rectal for men; 350 colon and 144 rectal for women). Compared to the lowest quintile, the relative risk and 95% confidence interval of developing cancer among the fifth quintile of marine n-3 polyunsaturated fatty acids intake were 0.60 and 0.31-1.14, respectively (p for trend = 0.04) in the colon in women and 0.35 and 0.14-0.88 (p for trend = 0.05) and 1.82 and 0.79-4.20 (p for trend = 0.16) in the proximal and distal colon, respectively, in men. For rectal cancer, the dose response for marine n-3 polyunsaturated fatty acids s was unclear; rather, we observed U-shaped associations in men and women. We found no evidence that n-6 polyunsaturated fatty acids increases or the n-3/n-6 ratio decreases the risk of colorectal cancer. Our results suggest that intake of marine n-3 polyunsaturated fatty acids may be inversely related to the risk of cancer in the proximal site of the large bowel.     

Breast cancer risk and erythrocyte compositions of n-3 highly unsaturated fatty acids in Japanese

Dietary intake of fish rich in n-3 highly unsaturated fatty acids (HUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been proposed to decrease cancer risk. In contrast to results from laboratory studies, however, protective effects for breast cancer have proved equivocal in epidemiological studies. In the present case-control study, we examined associations between breast cancer risk and fatty acid compositions in erythrocyte membranes as biomarkers for those intakes. Dietary information and blood samples were collected from 103 incident breast cancer cases and 309 non-cancer controls (matched by age and season) and erythrocyte fatty acids were measured using accelerated solvent extraction and gas-liquid chromatography. Dietary intake of n-3 HUFAs demonstrated a negative association with risk (the highest to the lowest tertile, odds ratio (OR), 0.51; 95% confidence interval (CI), 0.27-0.98; p(trend)<0.05), but there was no association with those of saturated fatty acids (SFAs) and meat. Moreover, risk was inversely associated with erythrocyte compositions of EPA (OR, 0.27; 95% CI, 0.14-0.53; p(trend)<0.0001), DHA (OR, 0.06; 95% CI, 0.02-0.16; p(trend)<0.0001) and n-3 HUFAs (OR, 0.11; 95% CI, 0.05-0.24; p(trend)<0.0001), and positively with that of SFAs (OR, 12.29; 95% CI, 4.94-30.57; p(trend)<0.0001) and the ratio of SFAs/n-3 HUFAs (OR, 14.65; 95% CI, 5.67-37.82; p(trend)<0.0001). In conclusion, we showed that erythrocyte compositions of specific fatty acids derived from fish intake, as biomarkers, are associated with lower risk of breast cancer, but further studies are needed to investigate mechanisms linked to the etiology.     

The 8-epimer of prostaglandin F(2alpha), a marker of lipid peroxidation and oxidative stress, is decreased in the nipple aspirate fluid of women with breast cancer

Breast cancer (BC), a worldwide disease with increasing incidence, develops from ductal/lobular epithelium. Nipple aspirate fluid (NAF), secreted from the breast ducts and lobules, can be analyzed to assess breast metabolic activity. Whether lipid peroxidation in the mammary gland promotes or prevents tumorigenesis is unclear. Malondialdehyde (MDA) and the 8-epimer of Prostaglandin F(2alpha) (8-iso-PGF(2alpha)), two lipid peroxidation markers, were studied in milk (n = 10), NAF (n = 140) and plasma (n = 35) samples. MDA was detected in all plasma, in 80% of milk samples and in 95% of NAF samples. MDA levels in NAF and plasma were significantly higher than in milk (p = 0.016 and p = 0.029, respectively). We found no significant difference between levels of MDA in NAF samples from BC patients compared to healthy controls. 8-iso-PGF(2alpha) was detectable in all samples. 8-iso-PGF(2alpha) median levels in NAF were significantly higher than in both milk and plasma (p < 0.0001). The highest 8-iso-PGF(2alpha) levels were found in NAF from healthy women, significantly higher than in women with BC (p < 0.0001). No significant differences were found in both markers after the age-adjustment. High levels of lipid peroxidation products in NAF suggest their in situ production in the nonlactating breast. Active lipid peroxidation may have a physiologic role in the normal mammary gland. Lower levels of 8-iso-PGF(2alpha) in NAF from BC patients suggest altered production of arachidonic acid metabolites during breast carcinogenesis.     

Do both heterocyclic amines and omega‐6 polyunsaturated fatty acids contribute to the incidence of breast cancer in postmenopausal women of the Malmö diet and cancer cohort?

Heterocyclic amines (HAs), formed when meat and fish are cooked at high temperatures, have been linked to mammary gland cancer in rats, and some epidemiological studies indicate increased breast cancer risk by consumption of well-done meat. The epidemiological evidence linking HAs per se to breast cancer is however sparse, especially from prospective studies. Moreover, high-fat diets rich in omega-6 polyunsaturated fatty acids (PUFAs) have produced higher frequencies of HA-induced mammary gland tumors in rats compared to those fed low-fat diets. The aim was to evaluate prospectively if intake of HAs is associated with breast cancer incidence, and if the association is independent of omega-6 PUFA intakes. Among women 50 years or older at baseline from the population-based prospective Malm? Diet and Cancer cohort (n = 11,699), 430 women were diagnosed with incident invasive breast cancer during a mean follow-up of 10.4 years. Information on dietary habits was collected by a modified diet history method. Cox proportional hazards regression estimated hazard ratios (HRs) and 95% confidence intervals (CIs) of breast cancer associated with energy-adjusted intakes of HAs and omega-6 PUFA. Intakes of HAs were not associated with breast cancer incidence (HR, 0.94; 95% CI, 0.69-1.28, for highest compared to lowest quintile). In individuals with low HA intakes, a significant increased risk was observed among those with high intakes of omega-6 PUFAs. In conclusion, intakes of HAs are not associated with breast cancer incidence in this Swedish cohort, but dietary patterns very high in omega-6 PUFA may promote breast cancer development.     

Effect of dietary modulation of membrane lipid composition on the thermostability of HTC cells and of a membrane enzyme

Growth of hepatoma tissue culture (HTC) cells in the presence of linoleic (18:2) or arachidonic (20:4) acids for 36 h caused an increased cell thermosensitivity. Plasma membrane-rich fractions were purified (15–20–fold) with high yield (30%) from control and fatty acid-supplemented cells. Contamination with membranes from mitochondria, lysosomes and endoplasmic reticulum was low. Supplementation significantly increased the level of the supplemented fatty acid and decreased the level of oleic acid (18:l) in plasma membrane phospholipids (PL), causing a significant decrease in the oleic acid:PUFA(polyunsaturated fatty acid) ratio. No significant changes occurred in other parameters such as cholesterol:PL, cholesterol:protein or PL:protein ratios. Plasma membranes from PUFA-supplemented cells exhibited a lower membrane order, compared with control cell membranes, as determined by DPH fluorescence polarization over the temperature range 4–40°C. Isothermal inactivation of alkaline phosphodiesterase I in plasma membranes from control and supplemented cells showed curvilinear kinetics. The change in membrane composition and order following supplementation with arachidonic acid was associated with increased thermosensitivity of this enzyme. These data are discussed with respect to the suggestion that the plasma membrane may be a target for cellular thermal injury and death.     

Influence of n-3 fatty acids on the growth of human breast cancer cellsin vitro: Relationship to peroxides and Vitamin-E

Epidemiological studies suggest a causal relationship of dietary polyunsaturated fatty acids (PUFA's) with the morbidity and mortality from breast cancer. In order to reveal possible underlying mechanisms of these findings, we studied the influence of n-3 and n-6 PUFA's in comparison to oleic acid on the proliferation of well characterized estrogen dependent (MCF-7, ZR-75, T-47-D) and estrogen independent (MDA-MB-231, HBL-100) breast cancer cells in culture. The cell growth inhibitory effect was related to the formation of lipid peroxidation products. Normal human skin fibroblasts served as a control. In fibroblasts, the addition of 20 µg/ml of exogenous fatty acids either had no effect or caused an insignificant increase of proliferation. Similar results were obtained with MCF-7 cells. In all other breast cancer cell types, n-3 long-chain PUFA's, eicosapentaenoic and docosahexaenoic acids, were the most effective fatty acids in arresting the cell growth. Alpha-linolenic and gamma-linolenic acid exerted a variable effect on cell proliferation depending on the cell line investigated. Oleic acid significantly stimulated the proliferation of hormone-independent breast cancer cells while it had no effect on the proliferation of hormone-dependent cells. Viability studies by trypan blue excretion indicated that the arrest in cell growth was not due to major cytotoxic effects.The addition of PUFA's to breast cancer cells caused a significant increase in the formation of conjugated dienes and lipid hydroperoxides in the cellular lipids; their content was significantly correlated with the capacity of arresting cell growth. In contrast, the addition of PUFA's to fibroblasts did not increase lipid hydroperoxide formation. The addition of Vitamin E to cancer cells at a concentration of 10 µM to the PUFA-supplemented medium almost completely restored cell growth.Our data indicate that PUFA's significantly interfere with cell proliferation of breast cancer cellsin vitro due to the formation of oxidation products. In addition to that, there must be other factors involved, most probably related to the differential metabolism of PUFA's in tumor cells. Our findings may have some impact on treatment and prevention of breast cancer.Abbreviations ALA Alpha-Linolenic Acid - GLA Gamma-Linolenic Acid - DHA Docosahexaenoic Acid - EPA Eicosapentaenoic Acid - ER Estrogen Receptor - OA Oleic Acid - PUFA's Polyunsaturated Fatty Acids     

Polyunsaturated fatty acids and risk of melanoma: A Mendelian randomisation analysis

Melanoma is the deadliest form of skin cancer, mainly affecting populations of European ancestry. Some observational studies suggest that particular diets reduce melanoma risk, putatively through an increase in polyunsaturated fatty acid (PUFA) consumption. However, interpretation of these observational findings is difficult due to residual confounding or reverse causality. To date, a randomized controlled trial has not been carried out to examine the relationship between PUFAs and melanoma. Hence, we performed a Mendelian randomisation (MR) study to evaluate the link between PUFAs and melanoma. To perform MR, we used summary results from the largest risk genome‐wide association study (GWAS) meta‐analysis of melanoma, consisting of 12,874 cases and 23,203 controls. As instrumental variables we selected SNPs associated with PUFA levels from a GWAS meta‐analysis of PUFA levels, from the CHARGE consortium. We used the inverse variance weighted method to estimate a causal odds ratio. To aid interpretation, we established a benchmark “large” predicted change in PUFAs in which, for example, an increase in docosahexaenoic acid (DPA) of 0.17 units (equal to 1 standard deviation) moves a person from the 17^th percentile to the median. Raising PUFA levels by a large amount (increasing DPA by 0.17 units) only negligibly changed melanoma risk: odds ratio [OR] = 1.03 (95% confidence interval [CI] = 0.96–1.10). Other PUFAs yielded similar results as DPA. Our MR analysis suggests that the effect of PUFA levels on melanoma risk is either zero or very small.