SETD4 Confers Cancer Stem Cell Chemoresistance in Nonsmall Cell Lung Cancer Patients via the Epigenetic Regulation of Cellular Quiescence

Figure 1

Characterization and enrichment of SETD4 in quiescent lung cancer stem cells (qLCSCs) from clinical nonsmall cell lung cancer (NSCLC) specimens. Representative immunofluorescence (IF) images of SETD4/Ki67 (a), SETD4/ALDH1 (b), and SETD4/CD133 (c) in tumor tissues from NSCLC patients. White arrow indicated SETD4-positive cells. DAPI, nuclear counterstaining. Scale bar, 20 μm. (d) Isolation of qLCSCs and A-qLCSCs from clinical lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) specimens. The left panel shows representative trypan blue staining images of primary patient-derived lung cancer cells after treatment with chemotherapy and radiotherapy. Dead cells were stained with trypan blue. Red arrows indicate surviving cells, which we referred to as qLCSCs. Then, qLCSCs were activated in tumorsphere formation medium after drug withdrawal for 48 hours. The middle panel shows a representative bright field image of A-qLCSCs. The right panel shows the tumorspheres formed by A-qLCSCs after cultivation for 7 days. Scale bar, 100 μm. Representative IF images of SETD4/Ki67 (e) and SETD4/ALDH1 (f) in qLCSCs and A-qLCSCs derived from clinical LUAD and LUSC specimens. DAPI, nuclear counterstaining. Scale bar, 50 μm. (g) Protein levels of SETD4, Ki67 and PCNA in qLCSCs and A-qLCSCs derived from the H1299 cell line, as detected by WB analysis. . GAPDH was used as an internal reference. The data are presented as the . ; .

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