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RUNX2 correlates with subtype-specific breast cancer in a human tissue microarray, and ectopic expression of Runx2 perturbs differentiation in the mouse mammary gland.

McDonald L, Ferrari N, Terry A, Bell M, Mohammed ZM, Orange C, Jenkins A, Muller WJ, Gusterson BA, Neil JC, Edwards J, Morris JS, Cameron ER, Blyth K - Dis Model Mech (2014)

Bottom Line: Using a human tumour tissue microarray, we show that high RUNX2 expression is significantly associated with oestrogen receptor (ER)/progesterone receptor (PR)/HER2-negative breast cancers and that patients with high RUNX2 expression have a poorer survival rate than those with negative or low expression.We show that ectopic Runx2 perturbs normal development in pubertal and lactating animals, delaying ductal elongation and inhibiting lobular alveolar differentiation.We also show that the Runx2 transgene elicits age-related, pre-neoplastic changes in the mammary epithelium of older transgenic animals, suggesting that elevated RUNX2 expression renders such tissue more susceptible to oncogenic changes and providing further evidence that this gene might have an important, context-dependent role in breast cancer.

View Article: PubMed Central - PubMed

Affiliation: Cancer Research UK Beatson Institute, Switchback Road, Bearsden, Glasgow, G61 1BD, UK.

ABSTRACT
RUNX2, a master regulator of osteogenesis, is oncogenic in the lymphoid lineage; however, little is known about its role in epithelial cancers. Upregulation of RUNX2 in cell lines correlates with increased invasiveness and the capacity to form osteolytic disease in models of breast and prostate cancer. However, most studies have analysed the effects of this gene in a limited number of cell lines and its role in primary breast cancer has not been resolved. Using a human tumour tissue microarray, we show that high RUNX2 expression is significantly associated with oestrogen receptor (ER)/progesterone receptor (PR)/HER2-negative breast cancers and that patients with high RUNX2 expression have a poorer survival rate than those with negative or low expression. We confirm RUNX2 as a gene that has a potentially important functional role in triple-negative breast cancer. To investigate the role of this gene in breast cancer, we made a transgenic model in which Runx2 is specifically expressed in murine mammary epithelium under the control of the mouse mammary tumour virus (MMTV) promoter. We show that ectopic Runx2 perturbs normal development in pubertal and lactating animals, delaying ductal elongation and inhibiting lobular alveolar differentiation. We also show that the Runx2 transgene elicits age-related, pre-neoplastic changes in the mammary epithelium of older transgenic animals, suggesting that elevated RUNX2 expression renders such tissue more susceptible to oncogenic changes and providing further evidence that this gene might have an important, context-dependent role in breast cancer.

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Ectopic RUNX2 expression leads to delayed differentiation and a lactation defect. (A) Whole-mount and histological analysis of MMTV-Runx2 glands (n=11) during late pregnancy (D17 pregnant) reveals a reduction in side-branching and alveolar expansion compared with WT (n=14), and failure to form mature alveolar units during lactation (WT n=13; Runx2 n=11). (B) Ki67 staining of WT and MMTV-Runx2 glands at day 12 (D12) pregnancy (n=4 each), late pregnancy (D17P; n=6 each) and day 1 of lactation (D1; WT n=6; Runx2 n=7). (C) Immunohistochemistry of whey acidic protein (WAP) and RUNX2 on serial sections at day 1 lactation in WT (n=6) and MMTV-Runx2 (n=7) glands illustrates their reciprocal expression pattern. (D) Quantification of Wap mRNA with dramatically less Wap in Runx2 glands at late pregnancy (d17P) and lactation (d1L); data are means ± s.d. normalised to HPRT relative to WT virgin. Whole-mounts, 8× magnification; H&Es, 200× magnification; IHC images, 100× magnification in B and 200× magnification in C.
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f3-0070525: Ectopic RUNX2 expression leads to delayed differentiation and a lactation defect. (A) Whole-mount and histological analysis of MMTV-Runx2 glands (n=11) during late pregnancy (D17 pregnant) reveals a reduction in side-branching and alveolar expansion compared with WT (n=14), and failure to form mature alveolar units during lactation (WT n=13; Runx2 n=11). (B) Ki67 staining of WT and MMTV-Runx2 glands at day 12 (D12) pregnancy (n=4 each), late pregnancy (D17P; n=6 each) and day 1 of lactation (D1; WT n=6; Runx2 n=7). (C) Immunohistochemistry of whey acidic protein (WAP) and RUNX2 on serial sections at day 1 lactation in WT (n=6) and MMTV-Runx2 (n=7) glands illustrates their reciprocal expression pattern. (D) Quantification of Wap mRNA with dramatically less Wap in Runx2 glands at late pregnancy (d17P) and lactation (d1L); data are means ± s.d. normalised to HPRT relative to WT virgin. Whole-mounts, 8× magnification; H&Es, 200× magnification; IHC images, 100× magnification in B and 200× magnification in C.

Mentions: Although MMTV-Runx2 transgenic females developed normally, were fertile and had normal litter sizes, mothers consistently failed to nurse their pups, which then died with little or no milk in their stomachs. WT and transgenic glands appeared phenotypically similar at mid-pregnancy, with comparable levels of proliferation (D12, Fig. 3B). However, defects in mammary gland architecture were observed by late pregnancy, with reduced ductal side-branching and alveolar expansion, and a failure of terminal differentiation resulting in a significant reduction in mature alveolar units (Fig. 3A). There was no difference in apoptosis of glands as assessed by caspase-3; however, inappropriate cell cycling (Fig. 3B) was seen in what should be a fully differentiated organ at lactation, exemplifying the delayed development of the post-parturient gland. The differentiation marker whey acidic protein (WAP; a constitutive milk protein) was detected at much lower levels compared with in WT (Fig. 3C,D) and was absent from areas showing high transgene expression (Fig. 3C), demonstrating a block in terminal alveolar differentiation.


RUNX2 correlates with subtype-specific breast cancer in a human tissue microarray, and ectopic expression of Runx2 perturbs differentiation in the mouse mammary gland.

McDonald L, Ferrari N, Terry A, Bell M, Mohammed ZM, Orange C, Jenkins A, Muller WJ, Gusterson BA, Neil JC, Edwards J, Morris JS, Cameron ER, Blyth K - Dis Model Mech (2014)

Ectopic RUNX2 expression leads to delayed differentiation and a lactation defect. (A) Whole-mount and histological analysis of MMTV-Runx2 glands (n=11) during late pregnancy (D17 pregnant) reveals a reduction in side-branching and alveolar expansion compared with WT (n=14), and failure to form mature alveolar units during lactation (WT n=13; Runx2 n=11). (B) Ki67 staining of WT and MMTV-Runx2 glands at day 12 (D12) pregnancy (n=4 each), late pregnancy (D17P; n=6 each) and day 1 of lactation (D1; WT n=6; Runx2 n=7). (C) Immunohistochemistry of whey acidic protein (WAP) and RUNX2 on serial sections at day 1 lactation in WT (n=6) and MMTV-Runx2 (n=7) glands illustrates their reciprocal expression pattern. (D) Quantification of Wap mRNA with dramatically less Wap in Runx2 glands at late pregnancy (d17P) and lactation (d1L); data are means ± s.d. normalised to HPRT relative to WT virgin. Whole-mounts, 8× magnification; H&Es, 200× magnification; IHC images, 100× magnification in B and 200× magnification in C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4007404&req=5

f3-0070525: Ectopic RUNX2 expression leads to delayed differentiation and a lactation defect. (A) Whole-mount and histological analysis of MMTV-Runx2 glands (n=11) during late pregnancy (D17 pregnant) reveals a reduction in side-branching and alveolar expansion compared with WT (n=14), and failure to form mature alveolar units during lactation (WT n=13; Runx2 n=11). (B) Ki67 staining of WT and MMTV-Runx2 glands at day 12 (D12) pregnancy (n=4 each), late pregnancy (D17P; n=6 each) and day 1 of lactation (D1; WT n=6; Runx2 n=7). (C) Immunohistochemistry of whey acidic protein (WAP) and RUNX2 on serial sections at day 1 lactation in WT (n=6) and MMTV-Runx2 (n=7) glands illustrates their reciprocal expression pattern. (D) Quantification of Wap mRNA with dramatically less Wap in Runx2 glands at late pregnancy (d17P) and lactation (d1L); data are means ± s.d. normalised to HPRT relative to WT virgin. Whole-mounts, 8× magnification; H&Es, 200× magnification; IHC images, 100× magnification in B and 200× magnification in C.
Mentions: Although MMTV-Runx2 transgenic females developed normally, were fertile and had normal litter sizes, mothers consistently failed to nurse their pups, which then died with little or no milk in their stomachs. WT and transgenic glands appeared phenotypically similar at mid-pregnancy, with comparable levels of proliferation (D12, Fig. 3B). However, defects in mammary gland architecture were observed by late pregnancy, with reduced ductal side-branching and alveolar expansion, and a failure of terminal differentiation resulting in a significant reduction in mature alveolar units (Fig. 3A). There was no difference in apoptosis of glands as assessed by caspase-3; however, inappropriate cell cycling (Fig. 3B) was seen in what should be a fully differentiated organ at lactation, exemplifying the delayed development of the post-parturient gland. The differentiation marker whey acidic protein (WAP; a constitutive milk protein) was detected at much lower levels compared with in WT (Fig. 3C,D) and was absent from areas showing high transgene expression (Fig. 3C), demonstrating a block in terminal alveolar differentiation.

Bottom Line: Using a human tumour tissue microarray, we show that high RUNX2 expression is significantly associated with oestrogen receptor (ER)/progesterone receptor (PR)/HER2-negative breast cancers and that patients with high RUNX2 expression have a poorer survival rate than those with negative or low expression.We show that ectopic Runx2 perturbs normal development in pubertal and lactating animals, delaying ductal elongation and inhibiting lobular alveolar differentiation.We also show that the Runx2 transgene elicits age-related, pre-neoplastic changes in the mammary epithelium of older transgenic animals, suggesting that elevated RUNX2 expression renders such tissue more susceptible to oncogenic changes and providing further evidence that this gene might have an important, context-dependent role in breast cancer.

View Article: PubMed Central - PubMed

Affiliation: Cancer Research UK Beatson Institute, Switchback Road, Bearsden, Glasgow, G61 1BD, UK.

ABSTRACT
RUNX2, a master regulator of osteogenesis, is oncogenic in the lymphoid lineage; however, little is known about its role in epithelial cancers. Upregulation of RUNX2 in cell lines correlates with increased invasiveness and the capacity to form osteolytic disease in models of breast and prostate cancer. However, most studies have analysed the effects of this gene in a limited number of cell lines and its role in primary breast cancer has not been resolved. Using a human tumour tissue microarray, we show that high RUNX2 expression is significantly associated with oestrogen receptor (ER)/progesterone receptor (PR)/HER2-negative breast cancers and that patients with high RUNX2 expression have a poorer survival rate than those with negative or low expression. We confirm RUNX2 as a gene that has a potentially important functional role in triple-negative breast cancer. To investigate the role of this gene in breast cancer, we made a transgenic model in which Runx2 is specifically expressed in murine mammary epithelium under the control of the mouse mammary tumour virus (MMTV) promoter. We show that ectopic Runx2 perturbs normal development in pubertal and lactating animals, delaying ductal elongation and inhibiting lobular alveolar differentiation. We also show that the Runx2 transgene elicits age-related, pre-neoplastic changes in the mammary epithelium of older transgenic animals, suggesting that elevated RUNX2 expression renders such tissue more susceptible to oncogenic changes and providing further evidence that this gene might have an important, context-dependent role in breast cancer.

Show MeSH
Related in: MedlinePlus