Fig. 2: SOX2, ASCL1 and INSM1 expression in the ASCL1-induced pulmonary neuroendocrine carcinoma and SCLC cell lines.
From: Distinct transcriptional programs of SOX2 in different types of small cell lung cancers
a WB analysis showed that the transfection of ASCL1 in A549 ADC cells increased SOX2, INSM1, and WNT11 expression. β-ACTIN served as an internal control. b Tumor tissues by the xenotransplantation of mock A549 cells and ASCL1-transfected A549 cells in immunodeficient mice. Using immunohistochemistry (IHC), ASCL1 transfection induced SOX2 protein expression in tumor cell nuclei. Representative images are shown. Scale bar = 200 μm. c Changes in transcriptional regulation driven by SOX2 between ASCL1-transfected A549 and A549 mock cells. ChIP- and RNA-seq combined data showed 35 specific SOX2-bound genes in ASCL1-transfected A549. INSM1 was newly detected after the transfection of ASCL1. Five genes, INSM1, SV2B, ADORA2A, OTULINL, and ACAP3, were shared with 346 SOX2-bound genes that were specific for SCLC-A subtype cell lines (red color). d An integrated genome viewer snapshot showed SOX2 binding at the overlapping region of the transcription starting site of the INSM1 and ASCL1 gene in SCLC cell lines. The fold enrichment values of SOX2 peak on INSM1 loci calculated by MACS2 are 23.79 in H69, 19.1 in H889, 8.79 in A549 ASCL1-TF, and no enrichment in SBC3 and A549 cells. The fold enrichment value on ASCL1 loci is 7.17 in H889 cells. These values are calculated against random Poisson distribution with local lambda. e The suppression of SOX2 by RNAi for ASCL1 was confirmed in H889 and SBC1 cells by WB analysis. f IHC images of surgically resected SCLC tissues for SOX2, ASCL1, and INSM1. These proteins were strongly expressed in tumor cell nuclei. Representative images are shown. Scale bar = 200 μm. g Expression levels of ASCL1, INSM1, and SOX2 in the RNA-seq dataset of SCLC tissues. The GSE60052 (n = 79) dataset [20] was analyzed. NT nontreated, si small interfering.
