Figure 6
Ectopic expression of PDZK1 stimulates growth and enhances E2-promoted growth of MCF-7 cells. (A) MCF-7 cells were transfected with an expression vector encoding human PDZK1 or control empty vector (pcDNA3.1). Protein extracts from these cells were subjected to immunoblot analysis with antibodies to PDZK1 or GAPDH. (B) Growth rates of PDZK1-expressing or control vector transfected MCF-7 cells were determined 24 or 48 h after plating in the absence of E2 by using the MTT assay. Data are expressed as percentage of growth at time 0. *Difference from control vector-transfected cells; p < 0.05. (C) Exponentially growing PDZK1-expressing or control vector transfected MCF-7 cells were collected, and protein extracts were prepared and subjected to immunoblot analysis with antibodies to c-Myc, PDZK1 or GAPDH. (D) Growth rates of the cells assessed in the presence of 1 nmol/L E2. Data are expressed as percentage of growth of untreated cells. *Difference from control vector-transfected cells; p < 0.05. (E) PDZK1-expressing or control vector transfected MCF-7 cells were treated with 1 nmol/L E2 or left untreated for 24 h. Cells were collected and total RNA was prepared and subjected to conventional RT-PCR with primers specific to human PDZK1 or β-actin.