FIG. 6.
LIF/JAK/STAT3 signaling in small cell lung cancer cell lines. (A) Production and secretion of LIF was analyzed by Western hybridization of cell culture media from H209 and H209Raf cells or DMS53 and DMS53Raf cells treated with estradiol for 2 days. (B) H209 or DMS53 cells were treated for 2 days with LIF or Raf-E2-CM produced from TTRaf cells, and phosphorylation of tyrosine 705 residue of STAT3 was analyzed. (C) H209 or DMS53 cells were treated for 2 days with LIF, and activation of STAT3 was analyzed. The data presented are fold increases of activity upon LIF treatment. Data (means ± standard deviations) are from a representative experiment performed in triplicate. Experiments were repeated at least three times with similar results.