Figure 4.
p38 controls MICA and PVR ligand upregulation on drug-treated MM cells through E2F1 transcription factor. (A) SKO-007(J3) cells were treated with VCR for 24 h at 37°C. Cell lysates were immunoblotted with phospho-E2F1-Ser364, anti-E2F1, or with anti β-actin, used as loading control. Where indicated cells were pre-treated with SB203580 or Caffeine. Data shown are representative of 1 out of 2 independent experiments. (B) ULBP-1, MICA, and PVR surface expression was analyzed by flow cytometry on shRNA-Scr or shRNA-E2F1 lentivirus-infected SKO-007(J3) cells, treated with VCR for 48 h. Data are representative of 1 out of 3 independent experiments. The light gray histogram represents the isotype control antibody, dark gray histogram represents the basal expression of specific ligands, while full line represents VCR-treated cells. (C) shRNA-Scr or shRNA-E2F1 lentivirus-infected SKO-007(J3) cells were treated with VCR for 24 h, and mRNA ligand expression was evaluated by real-time PCR. Data represent the mean of at least three independent experiments. *p ≤ 0.05.