Figure 3

Perhexiline treatment inhibits neuregulin-mediated activation of downstream signaling and cell proliferation. (A) MDA-MB-468 cells were cultured in the absence or presence of perhexiline (10 μM) for 6 hours, and subsequently stimulated with DMSO or NRGβ1 (10 ng/ml) for 10 minutes. Cell lysates were analyzed for the phosphorylation of HER3 (Tyr1289), Akt and ERK1/2 as well as total HER3 expression. (B) Perhexiline inhibits NRGβ1-induced cell growth. MB-MDA-468 cells were treated for 72 hours with vehicle (0.2% BSA in PBS) or NRGβ1 (10 ng/ml) in the presence of DMSO or perhexiline (2 μm). Cell growth was measured using the MTS assay. NRGβ1 treatment resulted in 33.5% increase of cell proliferation. Perhexiline inhibits 11.5% cells in vehicle media and 36.3% cell growth in NRGβ1 media. Data are presented as the mean ± SEM (n = 3). The statistical significance between DMSO control and perhexiline treatment in vehicle media or NRGβ1 media was analyzed by a two-tailed Student’s t test, (with ^* P <0.05 defined as significant compared to the control group with only NRGβ1 treatment). BSA, bovine serum albumin; DMSO, dimethyl sulfoxide; ERK, extracellular signal-regulated protein kinase; HER3, human epidermal growth factor receptor 3; NRGβ1, neuregulin β1; PBS, phosphate-buffered saline; SEM, standard error of the mean.