Correction: Associations and Interactions between Ets-1 and Ets-2 and Coregulatory Proteins, SRC-1, AIB1, and NCoR in Breast Cancer

Western blot analysis of Ets-1 and Ets-2 protein levels in breast cancer cells. Illustrative blots of breast cancer cells. Responder (endocrine sensitive MCF7) and Non Responder (endocrine insensitive SKBR3 cells) response to stimulation (Stim) with EGF (10 ng/mL) for 24 hours. Immunoblot carried out using rabbit anti-human Ets-1 (1 μg/mL) or rabbit anti-human Ets-2 (1 μg/mL) followed by corresponding horseradish peroxidase (1:2,000).

Note: The original work used primary breast cancer cultures and was carried out in 2002–2004, when surgical practices were different and wide local excision of primary tumors was common, which enabled collection of sufficient material to conduct functional molecular studies. Patients now undergo routine screening and present with smaller tumors. This, in combination with breast conserving surgery, means that primary tumor material is no longer available to undertake these studies. The cell lines used here provide a similar model of patients who respond (MCF7, endocrine sensitive) or not (SKBR3, endocrine insensitive) to therapy. These studies faithfully represent the original findings in the patient primary cells.

Western blot analysis of SRC-1 protein levels in breast cancer cells. Illustrative blots of breast cancer cells Responder (endocrine sensitive MCF7) and Non Responder (endocrine insensitive SKBR3 cells) response to stimulation (Stim) with EGF (10 ng/mL) for 24 hours. Immunoblot carried out using rabbit anti-human SRc-1 (2 μg/mL) followed by corresponding horseradish peroxidase (1:2,000).

Note: In the original manuscript a small increase was detected between control and stimulated in the non-responder cells. In this repeated experiment, higher levels of the protein were detected. However, greater differences were seen between control and stimulated in the sensitive cells in line with the original findings. Additionally, the original work used primary breast cancer cultures and was carried out in 2002–2004, when surgical practices were different and wide local excision of primary tumors was common, which enabled collection of sufficient material to conduct functional molecular studies. Patients now undergo routine screening and present with smaller tumors. This, in combination with breast conserving surgery, means that primary tumor material is no longer available to undertake these studies. The cell lines used here provide a similar model of patients who respond (MCF7, endocrine sensitive) or not (SKBR3, endocrine insensitive) to therapy. These studies faithfully represent the original findings in the patient primary cells.

Ets-1 and Ets-2 interaction with SRC-1 and N-CoR in the SKBR3 cell line under control conditions and after stimulation with bFGF (5 ng/mL) or EGF (10 ng/L) was determined by coimmunoprecipitation. Cell pellets were immunoprecipitated with either anti-SRC-1 or anti-N-CoR and subsequently immunoblotted with anti Ets-1 or anti-Ets-2.