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. Author manuscript; available in PMC: 2016 May 18.
Published in final edited form as: Oncogene. 2015 Jul 6;35(9):1143–1152. doi: 10.1038/onc.2015.169

Figure 6. LRIG1 down-regulation drives fulvestrant-mediated ErbB3 up-regulation.

Figure 6

A. Western analysis of whole cell lysates harvested form cells stably expressing pcDNA3.1 or LRIG1-WT. Cells cultured in 10% serum and with fulvestrant (1μM) or DMSO for 24 h.

B. Western analysis of whole cell lysates or avidin-biotin pull-downs from cells labeled with or without biotin for 30 minutes following 24 h treatment with fulvestrant or DMSO.

C. Cells expressing pcDNA3, LRIG1-WT, LRIG1-ΔEcto, or LRIG1-ΔCyto were cultured in 10% serum with fulvestrant (1μM) or DMSO for 7 d. Cells were collected by trypsinization and counted. Average cell number (± S.D.) is shown. N = 5, each counted in duplicate. Student’s T-test.

D. Western analysis of whole cell lysates harvested form cells stably expressing pcDNA3.1 or LRIG1-WT. Cells cultured in 10% serum for 7 days, and with fulvestrant (1μM) for the final 3 days or 7 days, or cultured with DMSO for 7 days.

E. Schematic of how ERα-induced expression of LRIG1 maintains ErbB3 at low levels in luminal breast cancer cells. Endocrine inhibitors, such as fulvestrant, tamoxifen, or aromatase inhibitors would cause reduced LRIG1 expression levels, thus allowing ErbB3 accumulation at the cell surface.