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Regulator of G-protein signaling 5 (RGS5) protein: a novel marker of cancer vasculature elicited and sustained by the tumor's proangiogenic microenvironment.

Silini A, Ghilardi C, Figini S, Sangalli F, Fruscio R, Dahse R, Pedley RB, Giavazzi R, Bani M - Cell. Mol. Life Sci. (2011)

Bottom Line: Supporting these findings, we show elevated levels of Rgs5 mRNA in the stroma from strongly (as opposed to weakly) angiogenic ovarian carcinoma xenografts and accordingly, we also show more of the protein associated to the abnormal vasculature.RGS5 protein predominantly colocalizes with the endothelium expressing platelet/endothelial cell adhesion molecule-1 (PECAM-1/CD31) and to a much lesser extent with perivascular/mural cells expressing platelet-derived growth factor receptor-beta (PDGFR-β) or alpha smooth muscle actin (αSMA).To toughen the relevance of the findings, we demonstrate RGS5 in the blood vessels of other cancer models endowed with a proangiogenic environment, such as human melanoma and renal carcinoma xenografts; to the contrary, it was undetectable in the vasculature of normal mouse tissues.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology, Laboratory of Biology and Treatment of Metastases, MarioNegri Institute for Pharmacological Research, Milan, Italy.

ABSTRACT
We previously identified regulator of G-protein signaling 5 (RGS5) among several genes expressed by tumor-derived endothelial cells (EC). In this study, we provide the first in vivo/ex vivo evidence of RGS5 protein in the vasculature of ovarian carcinoma clinical specimens and its absence in human ovaries. Consistent with this, we show higher amounts of Rgs5 transcript in EC isolated from human cancers (as opposed to normal tissues) and demonstrate that expression is sustained by a milieu of factors typical of the proangiogenic tumor environment, including vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF-2). Supporting these findings, we show elevated levels of Rgs5 mRNA in the stroma from strongly (as opposed to weakly) angiogenic ovarian carcinoma xenografts and accordingly, we also show more of the protein associated to the abnormal vasculature. RGS5 protein predominantly colocalizes with the endothelium expressing platelet/endothelial cell adhesion molecule-1 (PECAM-1/CD31) and to a much lesser extent with perivascular/mural cells expressing platelet-derived growth factor receptor-beta (PDGFR-β) or alpha smooth muscle actin (αSMA). To toughen the relevance of the findings, we demonstrate RGS5 in the blood vessels of other cancer models endowed with a proangiogenic environment, such as human melanoma and renal carcinoma xenografts; to the contrary, it was undetectable in the vasculature of normal mouse tissues. RGS5 expression by the cancer vasculature triggered and retained by the proangiogenic microenvironment supports its exploitation as a novel biomarker and opens the path to explore new possibilities of therapeutic intervention aimed at targeting tumor blood vessels.

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RGS5 expression by human endothelial cells (EC). a Rgs5 mRNA is much more expressed in tumor-than in normal tissue-derived EC. EC—isolated from human carcinomas or normal tissue specimens—were grown in presence of the proangiogenic factors VEGF, FGF-2 and EGF and investigated to assess Rgs5 mRNA by real-time PCR. Statistical analysis evaluated the dCt values. The y-axis indicates the relative expression: tumor-EC = black circles, normal tissue-EC = white circles, lines = median values. Fibroblasts (white squares) and uaSMC (white triangle) performed as the normal tissue EC. b Rgs5 mRNA expression by tumor-derived EC is fueled by angiogenic growth factors. Rgs5 mRNA was evaluated in tumor-derived EC grown in presence of a tumor/angiogenic microenvironment (as in a) and subsequent to its withdrawal. The arrows indicate the declining of expression. c RGS5 protein is expressed by tumor-EC growing in vitro. RGS5 protein (green, first panel) in representative EC isolated from an ovarian carcinoma specimen whose endothelial origin was verified by positive staining for CD31 (green) and vWF (red), by LDL uptake (red), by morphology (brightfield) and cord formation
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Fig1: RGS5 expression by human endothelial cells (EC). a Rgs5 mRNA is much more expressed in tumor-than in normal tissue-derived EC. EC—isolated from human carcinomas or normal tissue specimens—were grown in presence of the proangiogenic factors VEGF, FGF-2 and EGF and investigated to assess Rgs5 mRNA by real-time PCR. Statistical analysis evaluated the dCt values. The y-axis indicates the relative expression: tumor-EC = black circles, normal tissue-EC = white circles, lines = median values. Fibroblasts (white squares) and uaSMC (white triangle) performed as the normal tissue EC. b Rgs5 mRNA expression by tumor-derived EC is fueled by angiogenic growth factors. Rgs5 mRNA was evaluated in tumor-derived EC grown in presence of a tumor/angiogenic microenvironment (as in a) and subsequent to its withdrawal. The arrows indicate the declining of expression. c RGS5 protein is expressed by tumor-EC growing in vitro. RGS5 protein (green, first panel) in representative EC isolated from an ovarian carcinoma specimen whose endothelial origin was verified by positive staining for CD31 (green) and vWF (red), by LDL uptake (red), by morphology (brightfield) and cord formation

Mentions: Our previous microarray analysis investigation—aimed at finding novel markers of tumor vasculature—listed RGS5 among the genes highly expressed by tumor-derived EC [6]. In the present study, primary cultures of endothelial cells were investigated by real-time PCR. We demonstrate a statistically significant higher level of Rgs5 transcript in EC isolated from human carcinomas (mostly ovarian) in comparison to EC isolated from non-neoplastic tissue (adrenal glands and skin). As shown in Fig. 1a, the relative expression of Rgs5 mRNA is at least ten times higher in respect to normal tissue-derived EC, and also to commercially available human smooth muscle cells and fibroblasts (that performed as the normal tissue-derived EC).Fig. 1


Regulator of G-protein signaling 5 (RGS5) protein: a novel marker of cancer vasculature elicited and sustained by the tumor's proangiogenic microenvironment.

Silini A, Ghilardi C, Figini S, Sangalli F, Fruscio R, Dahse R, Pedley RB, Giavazzi R, Bani M - Cell. Mol. Life Sci. (2011)

RGS5 expression by human endothelial cells (EC). a Rgs5 mRNA is much more expressed in tumor-than in normal tissue-derived EC. EC—isolated from human carcinomas or normal tissue specimens—were grown in presence of the proangiogenic factors VEGF, FGF-2 and EGF and investigated to assess Rgs5 mRNA by real-time PCR. Statistical analysis evaluated the dCt values. The y-axis indicates the relative expression: tumor-EC = black circles, normal tissue-EC = white circles, lines = median values. Fibroblasts (white squares) and uaSMC (white triangle) performed as the normal tissue EC. b Rgs5 mRNA expression by tumor-derived EC is fueled by angiogenic growth factors. Rgs5 mRNA was evaluated in tumor-derived EC grown in presence of a tumor/angiogenic microenvironment (as in a) and subsequent to its withdrawal. The arrows indicate the declining of expression. c RGS5 protein is expressed by tumor-EC growing in vitro. RGS5 protein (green, first panel) in representative EC isolated from an ovarian carcinoma specimen whose endothelial origin was verified by positive staining for CD31 (green) and vWF (red), by LDL uptake (red), by morphology (brightfield) and cord formation
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3299962&req=5

Fig1: RGS5 expression by human endothelial cells (EC). a Rgs5 mRNA is much more expressed in tumor-than in normal tissue-derived EC. EC—isolated from human carcinomas or normal tissue specimens—were grown in presence of the proangiogenic factors VEGF, FGF-2 and EGF and investigated to assess Rgs5 mRNA by real-time PCR. Statistical analysis evaluated the dCt values. The y-axis indicates the relative expression: tumor-EC = black circles, normal tissue-EC = white circles, lines = median values. Fibroblasts (white squares) and uaSMC (white triangle) performed as the normal tissue EC. b Rgs5 mRNA expression by tumor-derived EC is fueled by angiogenic growth factors. Rgs5 mRNA was evaluated in tumor-derived EC grown in presence of a tumor/angiogenic microenvironment (as in a) and subsequent to its withdrawal. The arrows indicate the declining of expression. c RGS5 protein is expressed by tumor-EC growing in vitro. RGS5 protein (green, first panel) in representative EC isolated from an ovarian carcinoma specimen whose endothelial origin was verified by positive staining for CD31 (green) and vWF (red), by LDL uptake (red), by morphology (brightfield) and cord formation
Mentions: Our previous microarray analysis investigation—aimed at finding novel markers of tumor vasculature—listed RGS5 among the genes highly expressed by tumor-derived EC [6]. In the present study, primary cultures of endothelial cells were investigated by real-time PCR. We demonstrate a statistically significant higher level of Rgs5 transcript in EC isolated from human carcinomas (mostly ovarian) in comparison to EC isolated from non-neoplastic tissue (adrenal glands and skin). As shown in Fig. 1a, the relative expression of Rgs5 mRNA is at least ten times higher in respect to normal tissue-derived EC, and also to commercially available human smooth muscle cells and fibroblasts (that performed as the normal tissue-derived EC).Fig. 1

Bottom Line: Supporting these findings, we show elevated levels of Rgs5 mRNA in the stroma from strongly (as opposed to weakly) angiogenic ovarian carcinoma xenografts and accordingly, we also show more of the protein associated to the abnormal vasculature.RGS5 protein predominantly colocalizes with the endothelium expressing platelet/endothelial cell adhesion molecule-1 (PECAM-1/CD31) and to a much lesser extent with perivascular/mural cells expressing platelet-derived growth factor receptor-beta (PDGFR-β) or alpha smooth muscle actin (αSMA).To toughen the relevance of the findings, we demonstrate RGS5 in the blood vessels of other cancer models endowed with a proangiogenic environment, such as human melanoma and renal carcinoma xenografts; to the contrary, it was undetectable in the vasculature of normal mouse tissues.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology, Laboratory of Biology and Treatment of Metastases, MarioNegri Institute for Pharmacological Research, Milan, Italy.

ABSTRACT
We previously identified regulator of G-protein signaling 5 (RGS5) among several genes expressed by tumor-derived endothelial cells (EC). In this study, we provide the first in vivo/ex vivo evidence of RGS5 protein in the vasculature of ovarian carcinoma clinical specimens and its absence in human ovaries. Consistent with this, we show higher amounts of Rgs5 transcript in EC isolated from human cancers (as opposed to normal tissues) and demonstrate that expression is sustained by a milieu of factors typical of the proangiogenic tumor environment, including vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF-2). Supporting these findings, we show elevated levels of Rgs5 mRNA in the stroma from strongly (as opposed to weakly) angiogenic ovarian carcinoma xenografts and accordingly, we also show more of the protein associated to the abnormal vasculature. RGS5 protein predominantly colocalizes with the endothelium expressing platelet/endothelial cell adhesion molecule-1 (PECAM-1/CD31) and to a much lesser extent with perivascular/mural cells expressing platelet-derived growth factor receptor-beta (PDGFR-β) or alpha smooth muscle actin (αSMA). To toughen the relevance of the findings, we demonstrate RGS5 in the blood vessels of other cancer models endowed with a proangiogenic environment, such as human melanoma and renal carcinoma xenografts; to the contrary, it was undetectable in the vasculature of normal mouse tissues. RGS5 expression by the cancer vasculature triggered and retained by the proangiogenic microenvironment supports its exploitation as a novel biomarker and opens the path to explore new possibilities of therapeutic intervention aimed at targeting tumor blood vessels.

Show MeSH
Related in: MedlinePlus