Table 3.

Regulation of ER expression via co-culture with different cell types

Cell type	Breast cancer cell line(s)	Co-culture method	Δ ESR1 mRNA	Δ ER protein	Reference
Macrophages	MCF-7	CM	↓	↓	[156]
Primary human mammary fibroblasts (normal)	MCF-7, HMEC	Indirect (3D), direct (3D), CM	↓	N/A	[200]
Adipocytes	MCF-7	Indirect (transwell)	↓	N/A	[157]
Human mesenchymal stem cells	MDA-MB-231, T47D	Indirect (transwell), direct (in vivo mouse study)	Potential ↓(miR-221/222)	N/A	[201]
HS-5, HS-27a, primary human fibroblasts (CD146−/+ cancer-associated breast cancer tissues)	MCF-7	CM	↓	↓	[162]
HS-5, HS-27a, KM101, hFOB	MCF-7, T47D, BT-474	CM	↓	↓	[161]
HS-5, MDA-MB-231, MEF, MDA-MB-468, HS578T, HEK293, RMF/EG, MRC-5, THP-1, SK-BR-3, CV-1, MCF10A, BT-20	MCF-7, T47D	Direct	↓(HS-5)	↓(HS-5, RMF/EG, MRC-5, MDA-MB-231, CV-1, MCF10A, MDA-MB-468, HS-578T, THP-1)	[155]
HMF cell line	MCF-7	Indirect (3D)	↓	↓	[202]
Primary human fibroblasts (cancer-associated breast cancer tissues)	MCF-7	CM	↓(CAF derived from basal tumor)	↓(CAF derived from basal tumor)	[203]
Primary bone marrow stroma (normal donors)	T47D, MDA-MB-231	Direct	Potential ↓(miR-221/222)	N/A	[204]
Primary bone marrow stroma (normal and cancer-associated), HS-5	MCF-7, T47D	CM	↓	↓	[163]