Regulation of C/EBPα through p38 MAP kinase.

<p>(A): Double immunofluorescence of C/EBPα and proSP-C. Alveolar type II cells and alveolar macrophages in vehicle-injected mice were positive for C/EBPα expression, while p38 MAP kinase inhibitor, SB203580, suppressed C/EBPα expression only in alveolar type II cells. Arrow head: alveolar macrophage. Arrow: alveolar type II cells. (B): qRT-PCR analysis of <i>Cebpa</i> mRNA expression. SB203580 significantly suppressed <i>Cebpa</i> mRNA expression in whole lung samples (n = 3, *p<0.05). C/EBPα expression is regulated by p38 MAP kinase <i>in vivo</i>. ((C): qRT-PCR for tumor tissue gene expression. The data were normalized to the expression in whole lung tissues from 6 wk old mice (n = 4, solid circles). Open circles represent tumor samples. <i>Cebpa</i> and <i>MAPK14</i> mRNA expressions in tumors were significantly correlated (n = 13, r² = 0.832, p<0.0001, <i>Spearman's</i> correlation). (D): Double immunofluorescence of C/EBPα and p38 in C/EBPα partially positive tumors. In white rectangle in upper row, a high magnification clearly shows double-positive or –negative for C/EBPα and p38 expressions in tumor cells.