Key result
Treatment with Ang-(1-7) for 28 days reduced lung tumor xenograft volume by 30% compared to baseline, whereas saline-treated tumors increased 2.5-fold in size.
Why the study?
Does Angiotensin-(1-7) reduce tumor growth in athymic mice with human lung cancer xenografts?
Does Angiotensin-(1-7) reduce tumor growth in athymic mice with human lung cancer xenografts?
Angiotensin-(1-7) inhibits lung tumor growth in a xenograft model, potentially through reduction of COX-2 activity.
Answers are grounded in this paper and cite their sources.
Hypothesis-generating in lung cancer xenografts; leaves open clinical translation pending human trials.
Angiotensin-(1-7) [Ang-(1-7)] is an endogenous peptide of the renin-angiotensin system with vasodilator and antiproliferative properties. Our previous studies showed that Ang-(1-7) reduced serum-stimulated growth of human lung cancer cells in vitro through activation of a unique AT((1-7)) receptor. The current study investigates the effect of Ang-(1-7) on lung tumor growth in vivo, using a human lung tumor xenograft model. Athymic mice with tumors resulting from injection of A549 human lung cancer cells were treated for 28 days with either i.v. saline or Ang-(1-7), delivered by implanted osmotic mini-pumps. Treatment with Ang-(1-7) reduced tumor volume by 30% compared with the size before treatment; in contrast, tumor size in the saline-treated animals increased 2.5-fold. These results correlate with a reduction in the proliferation marker Ki67 in the Ang-(1-7)-infused tumors when compared with the saline-infused tumor tissues. Treatment with Ang-(1-7) significantly reduced cyclooxygenase-2 (COX-2) mRNA and protein in tumors of Ang-(1-7)-infused mice when compared with mice treated with saline as well as in the parent A549 human lung cancer cells in tissue culture. These results suggest that Ang-(1-7) may decrease COX-2 activity and proinflammatory prostaglandins to inhibit lung tumor growth. In contrast, the heptapeptide had no effect on COX-1 mRNA in xenograft tumors or A549 cells. Because Ang-(1-7), a peptide with antithrombotic properties, reduces growth through activation of a selective AT((1-7)) receptor, our results suggest that the heptapeptide represents a novel treatment for lung cancer by reducing COX-2.
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Menon et al. (2007) studied Human lung adenocarcinoma xenografts. Angiotensin-(1-7) vs. i.v. saline was evaluated on Tumor volume. Treatment with Ang-(1-7) for 28 days reduced lung tumor xenograft volume by 30% compared to baseline, whereas saline-treated tumors increased 2.5-fold in size.
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