Fig 1: Meningeal cells display KLF4K409Q-dependent FGF3 transcription and proliferate in response to FGF3(A) FGF3 and TRH mRNA expression in HBL-52 meningioma cells transfected with KLF4- or KLF4K409Q-expressing plasmids. Total RNA was purified 48 h posttransfection, and mRNA was amplified by RT-qPCR using GAPDH as internal control. Copy numbers were calculated per 106 copies of GAPDH mRNA in the same sample.(B) PCA Plot of RNA-seq meta-analysis in HMCs transduced with virus expressing KLF4 or KLF4K409Q proteins (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE156211. Clustering of samples shows batch effect: instead of clustering by conditions, the samples clustered by their Sample ID (i.e., 1, 2, 3, 4). See also Figure S5A.(C) Scatter plot showing activated and repressed DE genes in meta-analysis of RNA-seq in HMCs. FGF3 and TRH are marked by arrows. See also Venn diagrams in Figure S5B.(D) Proliferation response of meningioma cell line HBL-52 to recombinant FGF3, FGF1, and EGF. Cells were treated with human recombinant FGF3 or FGF1 at 0.1 µg/mL in the presence of 1 µg/mL of heparin or EGF at 5 ng/mL final concentrations in complete medium. Cell proliferation was measured on different days poststimulation (as marked) by Absorbance (OD value at 450 nm) using a Cell Counting Kit-8 [CCK-8] as described in Method details. Assay was set up in 96-well plates (starting at 1,000 cells/well), with eight replicates for each condition and repeated three times. Data are represented as mean ± SD (see also Figure S5, Tables S4 and S5).