Fig. 6: The PSPC1-CT131 is a dual inhibitor of oncogenic PSPC1 and PTK6.

a A cartoon of the primary domain structures of aligned DBHS family proteins with PSPC1-CT131 and Mut-NLS-CT131 (nuclear localization sequence (NLS) mutation of PSPC1-CT-131). b Top: PSPC1-CT131, but not Mut-NLS-CT131, colocalized with PSPC1 in the nucleus in Mahlavu cells shown by IF images. Middle: the line graphics of colocalization of PSPC1 (red) and EGFP-PSPC1-CT131 (green). Bottom: summary of merged color intensities of EGFP, EGFP-PSPC1-CT131, and EGFP-Mut-NLS-CT131 (green) with PSPC1 (red) and DAPI (blue for DNA) expressed in Mahlavu cells. The merged color intensities were calculated based on areas marked with dashed circles and confocal immunofluorescence analysis of data representing the mean ± SEM (n = 4). The scale bar represents 10 µm. c PSPC1-CT131 but not Mut-NLS-CT131 sequestered the active form of p-PTK6 in the nucleus of Mahlavu cells demonstrated by IF analysis. Colors are active PTK6 (p-PTK6) and PTK6 in red, EGFP for PSPC1-CT131 and Mut-NLS-CT131 in green, and nuclei stained with DAPI in blue. The scale bar represents 10 µm. d–f Cell migration (d), invasion (e), and spheroid formation (f). Data represent the mean ± SEM (n = 6). All data statistics were based on *p < 0.05, **p < 0.01, and ***p < 0.001 calculated by one-way ANOVA with Brown–Forsythe test. g Expression of PSPC1-CT131 but not Mut-NLS-CT131 altered the subcellular localization of PTK6, p-PTK6, and β-catenin determined by Western blotting analysis in Mahlavu cells. h Comparison of statistical significance based on the expression intensity of PSPC1 and PTK6 downstream genes in gene set enrichment signatures after transcriptome analysis (GSE114856) of indicated proteins in SK-hep1 cells and PSPC1-CT131 in Mahlavu cells in heatmap displays. Red and green colors indicate upregulation and downregulation of matched gene sets, respectively. The deeper the color, the lower the P-value, as shown in the scale bar. i Western blotting analysis indicated that the expression of EGFP-PSPC1-CT131 induced the upregulation of E-cadherin but decreased the expression of N-cadherin, Snail, Slug, Nanog, Oct4, p-PTK6, β-catenin, C-myc, PSPC1, and p-Smad2/3 in a dose-dependent manner. Source data are provided as a Source Data file.