Figure 4

Breast tumor kinase expression in breast cancer cell lines. (a) Total RNA was isolated from the breast cancer cell lines using the RNeasy kit (Qiagen), and the cDNA was generated using iScript cDNA synthesis (Bio-Rad). The cDNA was amplified using primers specifically for breast tumor kinase (Brk) or β-actin. The relative level of Brk mRNA was determined using densitometric analysis and was normalized to the amount of β-actin. The level of Brk mRNA in the MDA-MB-468 cell line was set to 1; numbers indicate the fold increase compared with the 468 cells. (b) Whole-cell lysates were prepared from the breast cancer cell lines. Lysates were immunoblotted with anti-Brk antibody (top) and with anti-Ran antibody (bottom). The relative expression of Brk protein was determined using densitometric analysis and was normalized to the amount of Ran. The expression of Brk protein in the MDA-MB-468 cell line was set to 1; numbers indicate the fold increase compared with the 468 cells.