Fig. 8.

B7-H1 was required in the activation of p38 MAPK through DNA-PKcs in breast cancer cells. (A–B) The levels of phospho-ERK or phospho-p38 MAPK and total ERK or total p38 MAPK in WT or B7-H1 KO MDA-MB-231 cells were analyzed by Western blotting (A) and flow cytometry (B). *P < 0.01 compared between B7-H1 WT and KO MDA-MB-231 cells. The whole gel images of (A) were provided as supplemental material. (C) The expression of phospho-p38 MAPK after incubation with NU7026 (10 μM, 24 hours). **P < 0.01 compared between NU7026 treated or not treated WT MDA-MB-231 cells. (D) Bcl-2 expression decreased in B7-H1 KO MDA-MB-231 cells compared to WT cells (**P < 0.01). Numbers of independent experiments (n = 3 in B, n = 6 in C, n = 3 in D). (E) B7-H1 wild type MDA-MB-231 cancer cells were incubated with DNA-PKcs inhibitor (NU7026 at 10 μM) or p38 MAPK inhibitor (SB203580 at 10 μM). Bar graph showed the expression of B7-H1 by MDA-MB-231 cells after 24–72 hours of culture with inhibitors or carrier control DMSO.