Figure 4

ARTEMIN (ARTN) regulates expression of TWIST1 in estrogen receptor (ER) negative mammary carcinoma (ER-MC). (a) Western blot analyses for TWIST1 in BT549 and MDA-MB-231 cells with forced expression or depletion of ARTN. β-ACTIN was used as loading control for cell lysates. The sizes of detected protein bands in kiloDalton (kDa) are shown on the right. (b) TWIST1 expression in BT549-vector (VEC) and BT549-ARTN cells determined by immunofluorescent microscopy. Bar, 62.7 μm. (c) ARTN and TWIST1 messenger RNA (mRNA) levels were detected in two immortal but otherwise normal mammary epithelial cell lines and 10 different human mammary carcinoma cell lines with different invasive potential. Quantitative PCR (qPCR) was performed to measure the mRNA expression of TWIST1 and ARTN. Relative expression was calculated compared with the level of expression in MCF7 cells. (d) Pearson's correlation coefficient was determined between the mRNA expression of ARTN and TWIST1 in two immortal but otherwise normal mammary epithelial cell lines and 10 different human mammary carcinoma cell lines. TWIST1 expression was positively correlated with ARTN expression (rho = 0.68).