Figure 4
G i α proteins are critical for breast cancer cell invasion in response to EGF, bFGF and IGF - 1. MB231 cells were transfected with scrambled or siRNA duplexes (combination of Gi1α and Gi3α, or Gi1α, Gi2α and Gi3α). After 24 hours, cells were trypsinized. (A-B) Cells were seeded in 6-well plates, grown in DMEM containing 5% or 10% FBS and followed for up to 6 days. (C-D) Cells were seeded in new plates for another 48 hours. Cells were re-trypsinized, seeded into 8 μm transwells pre-coated with matrigel and exposed to EGF (100 ng/ml), bFGF (25 ng/ml), IGF-1 (20 ng/ml), 10% FBS or left untreated (with serum free medium) for 36 hours. Penetrated cells were stained and recorded by an Olympus CKX41 microscopy with an Infinity 2 camera. *P value <0.01 (invaded breast cancer cells transfected with Gi1α, Gi2α and Gi3α siRNA duplexes were compared with cells transfected with scrambled siRNA duplexes). The experiments were repeated three times and similar results were obtained.