Fig. 6
High PRKD2 suppresses antigen-presentation pathways yet confers axitinib sensitivity. (A) ssGSEA comparing PRKD2-high vs. -low marrows: APC signalling, HLA machinery, CCR axis and type-II IFN response are all down-regulated in the high group. (B,C) HLA gene expression under PRKD2 manipulation: over-expression has little impact, whereas PRKD2 knock-down markedly elevates HLA-E. (D) RNA-seq of PRKD2-knockout myeloma cells. Loss of PRKD2 in RPMI-8226 cells lowers CD80 and FCGR1A while raising VEGFA (log2 FC ± SD, n = 3 replicates). (E) RNA-seq of PRKD2-over-expressing myeloma cells. Conversely, PRKD2 over-expression increases IL-6 and MERTK in the same cell lines (log2 FC ± SD, n = 3). (F) PD-L1 mRNA shows no difference between PRKD2 strata. (G) GDSC mining links rising PRKD2 to greater in-vitro sensitivity to the VEGFR/PDGFR inhibitor axitinib (Pearson r = 0.68). (H) Boxplot confirms higher axitinib sensitivity (lower IC50 index) in the PRKD2-high cohort. (I) Representative Annexin V/7-AAD density plots of vector control (LV3-vector, LV5-vector), PRKD2 knock-down (1965-PRKD2-KD) and PRKD2 over-expression (HOMO-PRKD2-OE) cells after 48 h exposure to DMSO or axitinib (1.25, 2.5, 5, 10 µM). Quadrants: Q1, necrotic; Q2, late apoptotic; Q3, early apoptotic; Q4, viable. (J) Quantification of total apoptosis (Q2 + Q3) from three independent experiments (mean ± SD). PRKD2-OE cells show significantly higher apoptosis than the LV5 control at every dose, whereas PRKD2-KD cells are intrinsically pro-apoptotic and further sensitised by axitinib. (K) Relative cell proliferation measured by CCK-8 after the same 48 h treatments. PRKD2 loss reduces basal growth and slightly lowers viability at 10 µM, while axitinib abolishes the proliferative advantage of PRKD2-OE cells. Statistical analysis: two-way ANOVA with Tukey’s multiple-comparison test; P < 0.05 versus corresponding vector control at the same concentration; *P < 0.05 versus DMSO within the same cell line. Error bars denote SD (n = 3).
