Limits...
Oestrogen increases the activity of oestrogen receptor negative breast cancer stem cells through paracrine EGFR and Notch signalling.

Harrison H, Simões BM, Rogerson L, Howell SJ, Landberg G, Clarke RB - Breast Cancer Res. (2013)

Bottom Line: CSC-enriched populations (ESA+CD44+CD24low) sorted from ER positive patient derived and established cell lines have low or absent ER expression.This effect was abrogated by the anti-oestrogen tamoxifen or ER siRNA.We demonstrate that gefitinib (epidermal growth factor receptor (EGFR) inhibitor) and gamma secretase inhibitors (Notch inhibitor) block oestrogen-induced CSC activity in vitro and in vivo but GSIs more efficiently reduce CSC frequency.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Introduction: Although oestrogen is essential for the development of the normal breast, adult mammary stem cells are known to be oestrogen receptor alpha (ER) negative and rely on paracrine signals in the mammary epithelium for mediation of developmental cues. However, little is known about how systemic oestrogen regulates breast cancer stem cell (CSC) activity.

Methods: Here, we tested the effects of oestrogen on CSC activity in vitro and in vivo and investigated which paracrine signalling pathways locally mediate oestrogen effects.

Results: CSC-enriched populations (ESA+CD44+CD24low) sorted from ER positive patient derived and established cell lines have low or absent ER expression. However, oestrogen stimulated CSC activity demonstrated by increased mammosphere and holoclone formation in vitro and tumour formation in vivo. This effect was abrogated by the anti-oestrogen tamoxifen or ER siRNA. These data suggest that the oestrogen response is mediated through paracrine signalling from non-CSCs to CSCs. We have, therefore, investigated both epidermal growth factor (EGF) and Notch receptor signals downstream of oestrogen. We demonstrate that gefitinib (epidermal growth factor receptor (EGFR) inhibitor) and gamma secretase inhibitors (Notch inhibitor) block oestrogen-induced CSC activity in vitro and in vivo but GSIs more efficiently reduce CSC frequency.

Conclusions: These data establish that EGF and Notch receptor signalling pathways operate downstream of oestrogen in the regulation of ER negative CSCs.

Show MeSH

Related in: MedlinePlus

In vivo assessment of oestrogenic effect on breast cancer stem cells. (A) Growth curves for xenografts produced from 1,000 cells pre-treated ± 17β-estradiol, ± inhibitors. *P = 0.01 (B) In vivo tumour formation in each group represented as mice positive for growth/mice tested displayed for each cell number tested. Tumour initiating cell frequency (95% CI) estimates calculated from limiting dilution analysis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3672803&req=5

Figure 5: In vivo assessment of oestrogenic effect on breast cancer stem cells. (A) Growth curves for xenografts produced from 1,000 cells pre-treated ± 17β-estradiol, ± inhibitors. *P = 0.01 (B) In vivo tumour formation in each group represented as mice positive for growth/mice tested displayed for each cell number tested. Tumour initiating cell frequency (95% CI) estimates calculated from limiting dilution analysis.

Mentions: The effect of 17β-estradiol on CSC activity and frequency, and its inhibition using tamoxifen, gefitinib and GSI, was assessed with limiting dilution of cells injected into NSG mice. The human cell origin of xenografts was verified using human specific pan-cytokeratin staining (see Additional file 5, Figure S4). A total of 1,000 injected cells pre-treated with 17β-estradiol initiated tumours (> 100 mm3) more quickly, and these tumours grew at a significantly faster rate than those formed from control cells or those treated with inhibitors (P < 0.001, Figure 5A).


Oestrogen increases the activity of oestrogen receptor negative breast cancer stem cells through paracrine EGFR and Notch signalling.

Harrison H, Simões BM, Rogerson L, Howell SJ, Landberg G, Clarke RB - Breast Cancer Res. (2013)

In vivo assessment of oestrogenic effect on breast cancer stem cells. (A) Growth curves for xenografts produced from 1,000 cells pre-treated ± 17β-estradiol, ± inhibitors. *P = 0.01 (B) In vivo tumour formation in each group represented as mice positive for growth/mice tested displayed for each cell number tested. Tumour initiating cell frequency (95% CI) estimates calculated from limiting dilution analysis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672803&req=5

Figure 5: In vivo assessment of oestrogenic effect on breast cancer stem cells. (A) Growth curves for xenografts produced from 1,000 cells pre-treated ± 17β-estradiol, ± inhibitors. *P = 0.01 (B) In vivo tumour formation in each group represented as mice positive for growth/mice tested displayed for each cell number tested. Tumour initiating cell frequency (95% CI) estimates calculated from limiting dilution analysis.
Mentions: The effect of 17β-estradiol on CSC activity and frequency, and its inhibition using tamoxifen, gefitinib and GSI, was assessed with limiting dilution of cells injected into NSG mice. The human cell origin of xenografts was verified using human specific pan-cytokeratin staining (see Additional file 5, Figure S4). A total of 1,000 injected cells pre-treated with 17β-estradiol initiated tumours (> 100 mm3) more quickly, and these tumours grew at a significantly faster rate than those formed from control cells or those treated with inhibitors (P < 0.001, Figure 5A).

Bottom Line: CSC-enriched populations (ESA+CD44+CD24low) sorted from ER positive patient derived and established cell lines have low or absent ER expression.This effect was abrogated by the anti-oestrogen tamoxifen or ER siRNA.We demonstrate that gefitinib (epidermal growth factor receptor (EGFR) inhibitor) and gamma secretase inhibitors (Notch inhibitor) block oestrogen-induced CSC activity in vitro and in vivo but GSIs more efficiently reduce CSC frequency.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Introduction: Although oestrogen is essential for the development of the normal breast, adult mammary stem cells are known to be oestrogen receptor alpha (ER) negative and rely on paracrine signals in the mammary epithelium for mediation of developmental cues. However, little is known about how systemic oestrogen regulates breast cancer stem cell (CSC) activity.

Methods: Here, we tested the effects of oestrogen on CSC activity in vitro and in vivo and investigated which paracrine signalling pathways locally mediate oestrogen effects.

Results: CSC-enriched populations (ESA+CD44+CD24low) sorted from ER positive patient derived and established cell lines have low or absent ER expression. However, oestrogen stimulated CSC activity demonstrated by increased mammosphere and holoclone formation in vitro and tumour formation in vivo. This effect was abrogated by the anti-oestrogen tamoxifen or ER siRNA. These data suggest that the oestrogen response is mediated through paracrine signalling from non-CSCs to CSCs. We have, therefore, investigated both epidermal growth factor (EGF) and Notch receptor signals downstream of oestrogen. We demonstrate that gefitinib (epidermal growth factor receptor (EGFR) inhibitor) and gamma secretase inhibitors (Notch inhibitor) block oestrogen-induced CSC activity in vitro and in vivo but GSIs more efficiently reduce CSC frequency.

Conclusions: These data establish that EGF and Notch receptor signalling pathways operate downstream of oestrogen in the regulation of ER negative CSCs.

Show MeSH
Related in: MedlinePlus