Expression of human apolipoprotein A-I/C-III/A-IV gene cluster in mice reduces atherogenesis in response to a high fat-high cholesterol diet

We have previously generated transgenic (Tg) mice expressing the human apolipoprotein (apo) A-I/C-III/A-IV gene cluster. This expression induced hyperlipidemia but reduced atherosclerotic lesions in genetically modified mice lacking apoE. Atherosclerosis is a multifactorial process and environmental factors such as diet play significant roles in its development. We examined here how an atherogenic diet influences the expression of the human genes and the characteristics of the Tg mice. Our results indicate that a high fat-high cholesterol diet up-regulates the intestinal expression of the three genes and the concentration of the three proteins in plasma. Cholesterol concentration was highly increased in the non-high density lipoprotein (HDL) fraction, and less, although significantly, in the HDL fraction. Tgs showed a 65% reduction in diet-induced aortic lesions compared with non-Tg mice. Atherogenic diet increases the expression of the genes encoding the scavenger receptor class B type I (SR-BI) and ATP binding cassette transporter 1 (ABCA1) proteins. As cholesterol efflux mediated by SR-BI or by ABCA1 was enhanced in Tg mice fed an atherogenic diet, we can hypothesize that increased reverse cholesterol transport is the basis of the protective mechanism observed in these animals. In conclusion, we present evidence that the expression of the human gene cluster in mice protects against atherogenesis in response to an atherogenic diet.

Antioxidative and antiatherosclerotic effects of human apolipoprotein A-IV in apolipoprotein E-deficient mice

Mice expressing human apolipoprotein A-IV (apoA-IV) mainly in the intestine were obtained in an apolipoprotein E-deficient (apoE(0)) background (apoA-IV/E(0) mice). Quantification of aortic lesions and plasma lipid determination showed that compared with their control apoE(0) counterparts, the apoA-IV/E(0) mice are protected against atherosclerosis without an increase in HDL cholesterol. Because oxidized lipoproteins play an important role in atherogenesis, we tested whether the protection observed in these animals is accompanied by an in vivo reduction of the oxidation parameters. The lag time in the formation of conjugated dienes during copper-mediated oxidation, the aggregation state of LDL, and the presence of anti-oxidized LDL antibodies were measured. The presence of oxidized proteins in tissues and the presence of oxidation-specific epitopes in heart sections of atherosclerotic lesions were also analyzed. Except for lag time, the results showed that the oxidation parameters were reduced in the apoA-IV/E(0) mice compared with the apoE(0) mice. This suggests that human apoA-IV acts in vivo as an antioxidant. In addition, human apoA-IV accumulation was detected in the atherosclerotic lesions of apoA-IV/E(0) mice, suggesting that apoA-IV may inhibit oxidative damage to local tissues, thus decreasing the progression of atherosclerosis.

Effect of ethyl esterification of phenolic acids on low-density lipoprotein oxidation

Inhibition of copper-induced low-density lipoprotein (LDL) oxidation by phenolic acids and their ethyl esters was investigated. LDL oxidation was evaluated by the hydroperoxide concentration and the chromatographic pattern of apoprotein fractions after fast protein liquid chromatography (FPLC). Antiradical properties against 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical and 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH) were also investigated, and lipophilicity determined by thin-layer chromatography. Caffeic acid at 5 microM and sinapic acid at 10 microM protected LDL against oxidation, inhibiting both hydroperoxide formation and the increase of apoprotein negative charge. Ferulic, gallic and p-hydroxy cinnamic acids were ineffective. Ethyl esterification increased the lipophilicity of the five acids, and enhanced the antioxidant properties of caffeic, sinapic and ferulic acids. Ethyl caffeate was protective at 1 microM. In contrast, gallic and p-hydroxy cinnamic ethyl esters were ineffective. Our results indicate that ethyl esterification of phenolic acids increases lipophilicity of their ethyl esters and may enable a better incorporation into the lipid layer of the LDL particle and the exertion of their antioxidant effect in the true site of lipoperoxidation. However, increasing lipophilicity is not the only mechanism able to potentiate preexisting antioxidant properties of molecules, and probably other mechanisms are implicated.

Expression of human apolipoprotein A-I/C-III/A-IV gene cluster in mice induces hyperlipidemia but reduces atherogenesis

The apolipoprotein (apo)A-I/C-III/A-IV gene cluster is involved in lipid metabolism and atherosclerosis. Overexpression of apoC-III in mice causes hypertriglyceridemia and induces atherogenesis, whereas overexpression of apoA-I or apoA-IV increases cholesterol in plasma high density lipoprotein (HDL) and protects against atherosclerosis. Each gene has been studied alone in transgenic mice but not in combination as the entire cluster. To determine which phenotype is produced by the expression of the entire gene cluster, transgenic mice were generated with a 33-kb human DNA fragment. The results showed that the transgene contained the necessary elements to direct hepatic and intestinal expression of the 3 genes. In the pooled data, plasma concentrations were 257+/-9, 7.1+/-0.5, and 1.0+/-0.2 mg/dL for human apoA-I, apoC-III, and apoA-IV, respectively (mean+/-SEM). Concentrations of these apolipoproteins were higher in males than in females. Human apoA-I and apoC-III concentrations were positively correlated, suggesting that they are coregulated. Transgenic mice exhibited gross hypertriglyceridemia and accumulation of apoB(48)-containing triglyceride-rich lipoproteins. Plasma triglyceride and cholesterol concentrations were correlated positively with human apoC-III concentration, and HDL cholesterol was correlated with apoA-I concentration. In an apoE-deficient background, despite being markedly hypertriglyceridemic, cluster transgenic animals compared with nontransgenic animals showed a 61% reduction in atherosclerosis. This suggests that apoA-I and/or apoA-IV can protect against atherosclerosis even in the presence of severe hyperlipidemia. These mice provide a new model for studies of the regulation of the 3 human genes in combination.

Human apolipoprotein A-IV reduces gastric acid secretion and diminishes ulcer formation in transgenic mice

We have investigated the involvement of human apolipoprotein A-IV (apoA-IV) in gastric acid secretion and ulcer formation in recently generated apoA-IV transgenic mice. Compared to control littermates, transgenic animals showed a gastric acid secretion decreased by 43-77% whereas only slight variations were observed in the different cell population densities within the gastric mucosa. In addition, no variation in gastrin levels was observed. Transgenics were protected against indomethacin-induced ulcer formation, with lesions diminishing by 45 to 64% compared to controls. These results indicate that endogenous apoA-IV expression can regulate gastric acid secretion and ulcer development.

Regulation of the human apolipoprotein AIV gene expression in transgenic mice

The apolipoprotein (Apo) AI-CIII-AIV gene cluster has a complex pattern of gene expression that is modulated by both gene- and cluster-specific cis-acting elements. In particular the regulation of Apo AIV expression has been previously studied in vivo and in vitro including several transgenic mouse lines but a complete, consistent picture of the tissue-specific controls is still missing. We have analysed the role of the Apo AIV 3' flanking sequences in the regulation of gene expression using both in vitro and in vivo systems including three lines of transgenic mice. The transgene consisted of a human fragment containing 7 kb of the 5' flanking region, the Apo AIV gene itself and 6 kb of the 3' flanking region (-7+6 Apo AIV). Accurate analysis of the Apo AIV mRNA levels using quantitative PCR and Northern blots showed that the 7+6 kb Apo AIV fragment confers liver-specific regulation in that the human Apo AIV transgene is expressed at approximately the same level as the endogenous mouse Apo AIV gene. In contrast, the intestinal regulation of the transgene did not follow, the pattern observed with the endogenous gene although it produced a much higher intestinal expression following the accepted human pattern. Therefore, this animal model provides an excellent substrate to design therapeutic protocols for those metabolic derangements that may benefit from variations in Apo AIV levels and its anti-atherogenic effect.

Curcumin and curcumin derivatives inhibit Tat-mediated transactivation of type 1 human immunodeficiency virus long terminal repeat

The transcription of HIV1 provirus is regulated by both cellular and viral factors. Various evidence suggests that Tat protein secreted by HIV1-infected cells may have additional action in the pathogenesis of AIDS because of its ability to also be taken up by non-infected cells. Curcumin [diferuloylmethane or 1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] is the yellow pigment in turmeric Curcuma longa (Linn). It exhibits a variety of pharmacological effects including antiinflammatory and antiretroviral activities. Here, we demonstrated that curcumin used at 10 to 100 nM inhibited Tat transactivation of HIV1-LTR lacZ by 70 to 80% in HeLa cells. In order to develop more efficient curcumin derivatives, we synthesized and tested in the same experimental system the inhibitory activity of reduced curcumin (C1), which lacks the spatial structure of curcumin; allyl-curcumin (C2), which possesses a condensed allyl derivative on curcumin that plays the role of metal chelator; and tocopheryl-curcumin (C3), which enhances the antioxidant activity of the molecule. Results obtained with C1, C2 and C3 curcumin derivatives showed a significant inhibition (70 to 85%) of Tat transactivation. Despite the fact that tocopheryl-curcumin (C3) failed to scavenge O2.-, this curcumin derivative exhibited the most activity; 70% inhibition was obtained at 1 nM, while only 35% inhibition was obtained with the curcumin.

Protective effects of the lipophilic redox conjugate tocopheryl succinyl-ethyl ferulate on HIV replication

Previously, we demonstrated that ferulate ethyl and tocopherol reduced HIV replication. In this study, we investigate whether the conjugation of both compounds (O-tocopheryl succinyl O-ethyl ferulate) can increase HIV inhibition. We show here for the first time that O-tocopheryl succinyl O-ethyl ferulate inhibits 80% of HIV replication (HIV-1 acute infection and HIV transmission), inhibits cell lipoperoxidation and prevents cellular glutathione consumption. Compared to ferulate ethyl and tocopheryl succinyl, O-tocopheryl succinyl O-ethyl ferulate inhibits more HIV replication. This may be due in part to the great increase in the lipophilicity of this compound.

The apolipoprotein A-I/C-III/A-IV gene cluster: ApoC-III and ApoA-IV expression is regulated by two common enhancers

Genetic, epidemiological and clinical evidence have clearly demonstrated the importance of the human apolipoprotein (apo) A-I/C-III/A-IV gene cluster in lipid metabolism and heart attack. The transcriptional regulation of these genes determines the level of the encoded proteins and therefore influences the concentration of triglycerides and cholesterol. Here, we analyze the existence of transcription control elements in the 6.6 kb apoC-III/A-IV intergenic region and their influence on the expression of both genes. Two main positive common control elements were found to modulate apoC-III and apoA-IV expression in HepG2 and in Caco-2 cells: the previously described apoC-III enhancer, located 0.8 kb upstream from the cap site of the gene, and a newly detected activating region located in the center of the intergenic sequence. The activity of both elements is highly increased by the hepatic and intestinal transcription factor HNF-4. Analysis of a 641 bp fragment containing the central element showed that it has the properties of a tissue-specific enhancer. Liver nuclear proteins interact with seven DNA binding sites present in this enhancer and HNF-4 specifically interacts with one of these sites. A third positive element, situated immediately upstream from the apoA-IV minimal promoter, is also activated by HNF-4; however, this element is not involved in apoC-III expression. In addition, two negative regions were identified, one located near the apoA-IV gene and the other one between the apoC-III enhancer and the newly identified central enhancer. In conclusion, negative and positive control elements are located in the apoC-III/A-IV intergenic region, including two enhancers important for the expression of the two genes. These results add new evidence that common regulatory elements for the expression of the apoA-I, apoC-III and apoA-IV genes are interspersed throughout the cluster.

The apolipoprotein AICIII-AIV gene cluster: sequence of the ApoCIII-ApoAIV intergenic region

The genes coding for human apolipoproteins AI, CIII and AIV are tandemly organised in a cluster on chromosome 11. The sequence of 4 kb of the 6.6-kb ApoCIII-ApoAIV intergenic region was unknown until now. Since different elements involved in the transcriptional regulation of the three genes of the cluster were previously identified in this region, we decided to sequence it. We present here the complete sequence of the region. Its availability will allow study of the transcriptional regulation of ApoCIII and ApoAIV at the molecular level. In addition, the use of PCR to study the polymorphic sites detected in the ApoCIII-ApoAIV intergenic region will now be possible. Some of these sites have been associated with lipid disorders and coronary heart disease.

Induction chemotherapy in head and neck cancer: results of a phase III trial

Between December 1982 and October 1986, 131 patients with stage II-III-IV squamous cell carcinoma of the oropharynx or oral cavity were randomized to induction chemotherapy, consisting of bleomycin (10 mg/m2/day in continuous infusion from day 1 to day 5), methotrexate (120 mg/m2 on day 2) followed by folinic acid, 5-fluorouracil (5 FU) (600 mg/m2 on day 2), and cisplatin (120 mg/m2 on day 4) every 4 weeks for a total of three cycles followed by definitive locoregional treatment versus locoregional treatment alone. The modalities of definitive treatment (radiotherapy +/- surgery) were chosen prior to randomization. A total of 116 patients were evaluable. Of 55 patients in the chemotherapy arm, four (7%) had a complete response (CR) and 23 (42%) a partial response (PR) following the induction regimen. At the completion of locoregional treatment, 76% (42 of 55) of patients in the experimental group were in CR compared to 89% (54 of 61) in the control group. There was no difference in survival, cause-specific survival, and pattern of relapse between both groups. The median survival was 22 months in the chemotherapy group and 29 months in the control group. Responders to chemotherapy did not fare better than nonresponders. Chemotherapy-related toxicities were few and most of them related to cisplatin which was reduced to 100 mg/m2 for 35 patients. There were no treatment-related deaths and, in the experimental arm of the trial, no increased morbidity from locoregional treatment. This induction regimen does not offer any advantages over standard treatment.

Randomized study of 5 fluorouracil and cis platin as neoadjuvant therapy in head and neck cancer: a preliminary report

A randomized prospective study of 5 fluorouracil (5-FU) and Cis platin preceding definitive local treatment for squamous cell carcinoma of the head and neck region was initiated in September 1986. Seventy-five patients were stratified by site (oral cavity-12, oropharynx-28, larynx-16, hypopharynx-19), and by Stage (Stage II-20, Stage III-43, Stage IV-12) and randomized to receive definitive local treatment (surgery and post-operative radiation or radiation alone) or chemotherapy followed by definitive local treatment. Chemotherapy consisted of three cycles of 120 hr 5-FU infusion 1 g/m2/day plus Cis platin 100 mg/m2 on day 1 on each cycle. Response to chemotherapy was complete in 17 patients (46%) for an overall response rate of 68%. All the patients have completed therapy with a median follow-up of more than 12 months. After local treatment, the complete response rate is 84% for the control group and 86% in the chemotherapy group. Actuarial disease-free survival at 1 year is 61% in the control group and 73% in the chemotherapy group (p = 0.25). These preliminary results show that in spite of initial tumor response, neoadjuvant chemotherapy does not improve long-term control and survival.

[Malignant mixed mesodermal tumor detected by uterine inversion. Apropos of a case. Review of the literature]

The authors report the anatomoclinical observation of an 82-year old patient presenting a mixed malignant mesodermal tumour (MMMT) revealed by a uterine inversion. The histological examination revealed sarcomatous and carcinomatous lesions with zones of chondroid metaplasia infiltrating largely the myometrium. A total vaginal hysterectomy, accompanied by radiotherapy, got the better of an early local relapse. The histogenetic hypotheses of MMMTs, the particular circumstances of the tumour revelation, as well as the methods of treatment are reviewed.