Angiotensin 1-7 formation in breast tissue is attenuated in breast cancer - a study on the metabolism of angiotensinogen in breast cancer cell lines.

The tissue renin-angiotensin system (RAS) plays an important role in the development and progression of many diseases. It has been confirmed that angiotensin II (ANG II) participates in the proliferation and angiogenesis of breast cancer. Moreover, some RAS dysregulations in cancer have been observed. Recent studies on the role of two opposite axes of angiotensinogen metabolism - ACE (angiotensin-converting enzyme)/ANGII/AT1R (angiotensin receptor type 1) and ACE-2/ANG 1-7/MAS (mitochondrial assembly) - indicate their importance in tumor growth and invasion, but studies describing the metabolic pathways in breast cancer and the role of newer angiotensins, such as ANG 1-12, remain lacking. In this study, the metabolism of angiotensinogen fragments in three breast cancer lines, namely, MDA-MB-231, MCF-7, and T-47D, compared with normal breast tissue cells (PCS-600) was estimated. Incubation of the cancer cells with angiotensinogen resulted in the prevalent formation of ANG 1-7. A difference in the ability to form ANG II was observed between cell lines. In normal breast cells, the strong predominance of the ACE-2/ANG 1-7/MAS pathway was detected. In cancer cells, differences in angiotensinogen metabolism depending on cancer line were observed; the prevalence of the ACE/ANG II/AT1R pathway was shown. Expressions of the RAS component were dysregulated in cancer cells and differed between cell lines. In conclusion, the ability of breast cancer cells to produce numerous angiotensin peptide metabolites was demonstrated. The metabolism of angiotensinogen differed between various types of breast cancer cells. The obtained results indicate the greater importance of the classical pathway - ACE/ANG II/AT1R - in breast cancer cells. The production of ANG 1-12 seems to be marginal in breast tissue, but a tendency for the higher formation of this peptide in cancer cells was observed. The production of ANG 1-7 was significantly lower in cancer cells, whereas the expression of MAS receptor was higher than that in the control. This finding suggests that substances with MAS receptor agonist activity could be useful in the treatment of breast cancer, but this requires further investigations.

Polymorphism in the chemokine receptor 7 gene (CCR7) is associated with previous myocardial infarction in patients undergoing elective coronary angiography.

Coronary artery disease (CAD) remains a major cause of death in developed countries. Both environmental and, less known, genetic factors contribute to progression of CAD to myocardial infarction (MI). Immune system is activated in patients with CAD through dendritic cells (DCs), which present plaque antigens to T lymphocytes. Production of proinflammatory cytokines by activated T cells contributes to plaque rupture in MI. Chemokine receptor 7 (CCR7) on DCs is required for their chemotaxis from plaque to lymph nodes. This makes possible an interaction of DCs with T lymphocytes and initiation of specific immune response. We hypothesized that single nucleotide polymorphisms (SNPs) in CCR7 gene locus are associated with previous MI in patients with CAD. To test this hypothesis, we genotyped six SNPs from the CCR7 gene locus in 300 consecutive patients, admitted for elective coronary angiography. We performed univariate-, multivariate- (including potential confounders) and haplotype-based tests of association of SNPs with previous MI and results of angiography. Allele A of rs17708087 SNP was associated with previous MI. This association remained significant after adjustment for age, sex, smoking, hypercholesterolaemia and drugs used by patients (odds ratio 2.13, 95% confidence interval: 1.13-3.86). Therefore, we conclude that CCR7 gene locus harbours a polymorphism that modifies risk of MI in patients with CAD. Replication of this association could be sought in a prospective cohort of initially healthy individuals.

Significant deterioration of anti-atherogenic efficacy of nebivolol in a double (apolipoprotein E and endothelial nitric oxide synthase) knockout mouse model of atherosclerosis in comparison to single (apolipoprotein E) knockout model.

Anti-atherogenic action of nebivolol in apolipoprotein E (apoE)-single knockout mouse model can be explained by its beneficial effect on endothelium, especially on endothelial nitric oxide synthase (eNOS). We, therefore, decided to use apoE and eNOS-double knockout mouse model to confirm that mechanism of nebivolol beneficial action. In apoE-single knockout mice, lesion area measured by "cross-section" of aortic roots was 79,244 ± 6,143 µm(2) in the control group versus 65,347 ± 6,152 µm(2) in nebivolol-treated group (P<0.05). However, in apoE and eNOS-double knockout mice, lesion area measured by "cross-section" of aortic roots was 92,319 ± 8,876 µm(2) in the control group versus 98,609 ± 9,164 µm(2) in nebivolol-treated group (P>0.05). The comparison between apoE-single knockout mice and apoE & eNOS-double knockout mice without treatment also showed statistically significant difference: 81,232 ± 8,264 µm(2) versus 92,319 ± 8,876 µm(2) (P<0.05). This is the first report that describes the effect of nebivolol on atherogenesis in apoE and eNOS-double knockout mice, proving directly the necessity of the presence of eNOS in endothelium for nebivolol to show its an anti-atherogenic potency.

The influence of angiotensin-(1-7) peptidomimetic (AVE 0991) and nebivolol on angiotensin I metabolism in aorta of apoE-knockout mice.

The detrimental role of over activation of renin-angiotensin system (RAS) in atherogenesis is widely recognized. Recently, we have demonstrated that Ang-(1-7) peptidomimetic - AVE0991, as well as known beta-adrenolytic agent nebivolol, exert anti-atherogenic actions in mouse model of atherosclerosis - apoE-knockout mice. Here, using LC-ESI-MS ex vivo system, we tested whether prolonged treatment of apoE-knockout mice by these drugs can influence RAS in aorta of apoE-knockout mice in regard to generation of most active metabolites of Ang I-Ang II and Ang-(1-7). As compared to wild type animals there was increased generation of Ang II in aorta of apoE-knockout mice, while the formation of Ang-(1-7) did not differ between both groups. Either treatment with AVE0991 or nebivolol resulted in significant attenuation of Ang II production in aorta of apoE-knockout mice. In conclusion, for the first time we directly demonstrated that there is increase in ability of aortic tissue to generate Ang II in mouse model of atherosclerosis of apoE knockout mice, and that such effect could be efficiently attenuated either by treatment of nebivolol or Ang-(1-7) peptidomimetic - AVE0991. The exact mechanism(s) responsible for interference of both drugs with RAS require further investigation.

Angiotensin-(1-7) receptor Mas agonist ameliorates progress of atherosclerosis in apoE-knockout mice.

Our interest focused on an open question whether AT-(1-7), nonpeptide receptor agonist: AVE 0991, is able to ameliorate atherosclerosis. We used an apolipoprotein E (apoE) - knockout mice model of atherosclerosis. Experimental groups received the same diet as control, mixed with: AVE 0991 at a dose of 0.58 µmol/kg b.w./day, perindopril at a dose of 0.4 mg/kg b.w./day or with tiorphan at a dose of 2.5 mg/kg b.w./day. A-779 [(D-alanine)-angiotensin (1-7)] was given at a dose of 3.3 mg/kg b.w., 3 times a week i.p. Measured by "en face" method, the percentage of occupied by Sudan IV-stained surfaces were as follows: 14.2±1.9 % in control group, whereas in AVE 0991-treated as well as in perindopril-treated groups percentages were statistically significantly lower. In tiorphan group there was no change comparing to control group, whereas in A-779 group percentage was statistically significantly higher. "Cross-section" of aortic roots revealed also the difference in atherosclerotic lesions. The mean surfaces, occupied by oil red O-stained changes were: 91.213±8.123 µm(2) in control group, while in AVE 0991-treated as well as in perindopril-treated groups lesions were statistically significantly lower. In tiorphan group there was no change; however, in A-779 group lesions were statistically significantly higher. Measured by real time RT-PCR relative p22phox (submit of NADPH oxidase) expression was significantly decreased in AVE 0991-treated mice. As revealed by flow cytometry, the expression of co-stimulatory molecules: CD86, CD80 and CD40 on both dendritic cells (CD11c+) and macrophages (F4/80+) was reduced in AVE 0991-treated group, which correlated with decreased expression of CD69 activation marker on CD4+T cells. In our report we showed the beneficial effect of AVE 0991 on atherogenesis in gene-targeted mice.

The effect of doxycycline on atherogenesis in apoE-knockout mice.

Doxycycline at subantimicrobial doses inhibits matrix metalloproteinases (MMPs) activity, and is the only MMP inhibitor which is widely available in clinical practice. The aim of the study was to reveal whether non-specific MMPs inhibition by tetracycline could ameliorate development of atherosclerosis in apolipoprotein E (apoE)-knockout mice. Doxycycline (1.5 mg/ kg b.w./day) administered orally attenuated atherogenesis, measured both by "en face" method (10.25±1.7% vs. 15.7±2.0%, p<0.05) and "cross-section" method (66,254±7,468 µm(2) vs. 90,687±8,521 µm(2), p<0.05). In-situ zymography showed decrease of the extent of non-specific gelatinase activity in doxycycline-treated mice This is the first report to date describing the effect of doxycycline on atherogenesis in apoE-targeted mice.

AVE 0991-angiotensin-(1-7) receptor agonist, inhibits atherogenesis in apoE-knockout mice.

Recent evidence shows that the renin-angiotensin system is a crucial player in atherosclerotic processes. It was also proved that Ang II promotes atherogenesis. Angiotensin-(1-7) [Ang-(1-7)] opposites Ang II action. Therefore, we would like to find out whether Ang-(1-7) receptor agonist: AVE 0991, could ameliorate atherosclerosis progression in an experimental model of atherosclerosis: apolipoprotein E (apoE) - knockout mice. AVE 0991 inhibited atherogenesis, measured both by "en face" method (7.63+/-1.6% vs. 14.6+/-2.1%) and "cross-section" method (47 235+/-7 546 microm(2) vs. 91 416+/-8 357 microm(2)). This is the first report showing the effect of AVE 0991 on atherogenesis in gene-targeted mice.

The effect of nebivolol on atherogenesis in apoE-knockout mice.

Nebivolol is a novel beta1-blocker with a nitric oxide (NO)--potentiating, vasodilatory effect that is unique among beta-blockers. It was already shown that nebivolol ameliorates atherosclerosis in cholesterol-fed rabbits. We, therefore, wanted to investigate whether this is the case in the fine experimental model of atherosclerosis: apolipoprotein E (apoE)-knockout mice. Nebivolol attenuated atherogenesis, measured both by "en face" method (9.23+/-1.8% vs. 14.6+/-2.1%) and "cross-section" method (63125+/-8455 microm(2) vs. 91416+/-8357 m(2)). This is the first report showing the effect of nebivolol on atherogenesis in gene-targeted mice.