6KR-EGFR expressing MCF7 following EGF or HRG stimulation

EGF and HRG, growth factor ligands for EGFR and ErbB3/4 receptor, induce transient and sustained ERK activity associated with cellular proliferation and differentiation of MCF-7 cells, respectively. To rigorously analyze the effect of ERK signal duration for mRNA expression dynamics and its relationship with cell determination, we modified the EGF-triggered ERK signal duration by changing the EGFR activation dynamics by impairing the ubiquitination and degradation process. Mutation of the six lysine residues (6KR; K692, K713, K730, K843, K905 and K946) of the EGFR responsible for ubiquitin conjugation has shown sustained phosphorylation of the receptor (Huang et al, 2006; Goh et al, 2010). Therefore we constructed the MCF-7 cell lines that stably express 6KR EGFR (6KR), and analyzed signaling and mRNA expression dynamics in response to EGF and HRG. 6KR-EGFR (6KR) expressing MCF7 human breast cancer cells were stimulated by the growth hormone (epidermal growth factor (EGF) or heregulin (HRG)). Control was set as non-treated cells.