Fig. 6: High activity of YAP signaling correlates with low baseline MITF expression and potential for decreased MITF transcription upon tankyrase inhibition.
a Expression of YAP signaling target transcripts (Ccn1, Ccn2, and Amotl2) for untreated human and murine B16-F10 melanoma cell lines. Seven of 19 samples displayed high relative transcription of YAP signaling target genes (YAPhigh) when compared to samples with less transcription (YAPlow). YAPhigh is highlighted by orange branches in the dendrogram and arrows. Scale bar indicates differences in Z-score (standard deviations < or > mean) values for log2 transcripts per millions (TPMs) within each row. Cancer stages: Metastatic in blue, radial growth phase (RGP) in pink and vertical growth phase (VGP) in green. b Baseline MITF expression in untreated samples (grey bars, log2-transformed TPMs × 10−1) and change upon treatment with G007-LK (1 µM) for 24 h (black dots sorted descending from left to right, log2 values from treated versus untreated TPMs). Samples with increased (MITF increased, left) or decreased (MITF decreased, right) expression of MITF upon tankyrase inhibitor treatment are separated by scattered vertical line. *Indicates that no value for untreated sample is inserted. For b, d B16-F10 WNT3a = WNT3a + G007-LK relative to WNT3a-stimulated control. YAPhigh cell lines are highlighted by orange arrows. c Real-time RT-qPCR analysis of Mitf expression in G007-LK-treated B16-F10 s.c. tumors versus control tumors (n = 8). Two-tailed Mann-Whitney rank sum test is indicated by ‡(P < 0.01). Boxplot shows median, first and third quartiles and maximum and minimum whiskers for data from two repeated measurements. d Changes in gene expression for WNT/β-catenin (Axin2 and Tcf7) and YAP (Ccn1, Ccn2, and Amotl2) signaling target genes for 18 G007-LK-treated (1 µM) human and murine B16-F10 melanoma cell lines. Downregulated signaling activity is indicated by ↓ (log2 < −0.2, highlighted in blue), upregulated activity is indicated by ↑ (log2 > 0.2, highlighted in pink), and inconclusive or lack of regulation is indicated by − . e Venn diagram depicting the cell lines intersecting profiles for pre-treatment (YAPhigh and MITF low) and response to G007-LK treatment (MITF decreased and YAP or WNTdecreased).
