Signaling pathways involved in BMP4-promoted autophagy in HCC. A. HepG2 and HCCLM3 cells were treated with BMP4 (100 ng/mL) or Noggin for 24 h, the protein expression and JNK and phosphorylation of JNK (p-JNK) were determined by Western blot. HepG2 and HCCLM3 cells were pretreated with JNK inhibitor SP600125 (20 μM) or for 30 min, followed by addition of BMP4, Western blot was performed to detect the expression of Beclin1 and LC3-II. JNK pathway inhibition by SP600125 significantly attenuated the BMP4-activated autophagy in HepG2 and HCCLM3 cells. B. HCC cells were pretreated with JNK pathway inhibitor by SP600125 (20 μM) for 6 h, then co-cultured with BMP4 for 24 h, cell invasion ability was analyzed by Transwell assay. SP600125 significantly attenuated cell invasion both in HepG2 and HCCLM3. Data are shown as mean ± SD and from three independent experiments. **: P < 0.01, ***: P < 0.001.