Early vascular deficits are correlated with delayed mammary tumorigenesis in the MMTV-PyMT transgenic mouse following genetic ablation of the NG2 proteoglycanReportar como inadecuado




Early vascular deficits are correlated with delayed mammary tumorigenesis in the MMTV-PyMT transgenic mouse following genetic ablation of the NG2 proteoglycan - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Breast Cancer Research

, 14:R67

First Online: 24 April 2012Received: 17 August 2011Revised: 16 March 2012Accepted: 24 March 2012

Abstract

IntroductionThe neuron-glial antigen 2 NG2 proteoglycan promotes pericyte recruitment and mediates pericyte interaction with endothelial cells. In the absence of NG2, blood vessel development is negatively impacted in several pathological models. Our goal in this study was to determine the effect of NG2 ablation on the early development and function of blood vessels in mammary tumors in the mammary tumor virus-driven polyoma middle T MMTV-PyMT transgenic mouse, and to correlate these vascular changes with alterations in mammary tumor growth.

MethodsThree different tumor paradigms spontaneous tumors, transplanted tumors, and orthotopic allografts of tumor cell lines were used to investigate the effects of NG2 ablation on breast cancer progression in the MMTV-PyMT transgenic mouse. In addition to examining effects of NG2 ablation on mammary tumor growth, we also investigated effects on the structure and function of tumor vasculature.

ResultsAblation of NG2 led to reduced early progression of spontaneous, transplanted, and orthotopic allograft mammary tumors. NG2 was not expressed by the mammary tumor cells themselves, but instead was found on three components of the tumor stroma. Microvascular pericytes, myeloid cells, and adipocytes were NG2-positive in both mouse and human mammary tumor stroma. The effect of NG2 on tumor progression therefore must be stromal in nature. Ablation of NG2 had several negative effects on early development of the mammary tumor vasculature. In the absence of NG2, pericyte ensheathment of endothelial cells was reduced, along with reduced pericyte maturation, reduced sprouting of endothelial cells, reduced assembly of the vascular basal lamina, and reduced tumor vessel diameter. These early deficits in vessel structure are accompanied by increased vessel leakiness, increased tumor hypoxia, and decreased tumor growth. NG2 ablation also diminishes the number of tumor-associated and TEK tyrosine kinase endothelial Tie2 expressing macrophages in mammary tumors, providing another possible mechanism for reducing tumor vascularization and growth.

ConclusionsThese results emphasize the importance of NG2 in mediating pericyte-endothelial cell communication that is required for proper vessel maturation and function. In the absence of normal pericyte-endothelial cell interaction, poor vascular function results in diminished early progression of mammary tumors.

AbbreviationsBSAbovine serum albumin

EGFPenhanced green fluorescent protein

FACSfluorescence activated cell sorting

FCSfetal calf serum

FGF2fibroblast growth factor-2

FITCfluorescein isothiocyanate

H and Ehematoxylin and eosin

LNlymph node

MINmammary intraepithelial neoplasia

MMTV-PyMTmammary tumor virus-driven polyoma middle T

NG2nerve-glial antigen 2

PBS: phosphate-buffered saline

SEstandard error

αSMAα-smooth muscle actin

VEGFvascular endothelial growth factor

VEGFR-3vascular endothelial growth factor receptor-3.

Electronic supplementary materialThe online version of this article doi:10.1186-bcr3174 contains supplementary material, which is available to authorized users.

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Autor: Krissa Gibby - Weon-Kyoo You - Kuniko Kadoya - Hildur Helgadottir - Lawrence JT Young - Lesley G Ellies - Yunchao Chang -

Fuente: https://link.springer.com/article/10.1186/bcr3174







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