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. 2013 Nov 19;8(11):e79843. doi: 10.1371/journal.pone.0079843

Figure 1. MDM2 inhibition stabilizes p53 and induces apoptosis and p53 signaling pathways in neuroblastoma cells.

Figure 1

(A) Consistent with our previously data [11], Western blotting showed an increase in p53 levels within 4 hours exposure to Nutlin-3a in p202, p218, and IMR32 cells, confirming that the p53 signaling pathway is active in our system. (B) Apoptosis induction was tested in five established neuroblastoma lines (JF, IMR32), early passage neuroblastoma tumor cultures (p202, p218, H), and four non-neuroblastoma human solid tumors including colorectal (HCT116), breast (MCF7) and osteosarcoma (SJSA-1). SJSA-1 line differs by the level of MDM2 expression, being amplified 25 fold. A p53 mutant neuroblastoma line (SJ3-12), which lacks part of the DNA binding domain, was used as control. Proliferating cells were treated with Nutlin-3a for 24 hours and TdT-positive fraction was measured by flow cytometry. (C) Pathways enriched upon Nutlin-3a treatment: p53 signaling (GSEA ID: M6370), DNA damage (GSEA ID: M8378), and chemotherapy response (bleo_human_lymph) genes. Vertical columns separate Nutlin-3a versus Nutlin-3b at 3, 8, and 16 hours, horizontal rows indicate genes.