FIG. 3.

Periostin secreted by tumor cells promotes angiogenic activities of HMVEC. (A) The conditioned media from parental, vector-transfected, or periostin-producing MCF-7 cells were collected, and periostin expression was determined by immunoblotting. (B) Tumor cell-derived periostin enhances HMVEC migration. The three types of cells indicated in panel A were grown in serum-free media for 48 h in the lower chamber of transwells. HMVEC were transferred onto the upper chamber, and trapped cells were counted 4 h later. (C) Tumor cell-derived periostin enhances proliferation of HMVEC. HMVEC were incubated with conditioned media derived from the three types of cells described in panel A for 12 h, and [³H]thymidine incorporation was measured following a labeling period of 6 h. *, P was <0.05 compared with parental or control cells.