Figure 1.

USP4 promotes lung cancer cell stemness and its high expression is correlated with human lung cancer patients. (A) The Oncomine dataset “Bhattacharjee Lung” was used to analyze Pearson correlation of USP4 and Oct4/Sox2 expression. (B–E) H1975 cells stably expressing shRNA against USP4 (shUSP4-#1 or shUSP4-#2) were subjected to (B) Western blot analyses, (C–D) FACS analyses for CD133-stained cells or (E) tumorsphere formation assay. Respective images and quantitation were shown. Data from three independent experiments in triplicates were presented as means ± SD. *** p < 0.001. Scale bar = 100 μm. (F–I) H1975 cells stably expressing Flag-USP4 or Flag-USP4^C311A were subjected to (F) Western blot analyses, (G) FACS analyses for CD133-stained cells or (H–I) tumorsphere formation assay. Respective images and quantitation were shown. Data from three independent experiments in duplicates were presented as means ± SD. ** p < 0.01, *** p < 0.001. Scale bar = 100 μm. (J) The Oncomine dataset “Gaber lung” was used to analyze USP4 mRNA levels in normal human lung tissues and lung cancers. (K) The Oncomine dataset “Bild lung” was used to analyze USP4 mRNA levels in stage I or stage II-IV human lung cancers. (L) The Oncomine dataset “Raponi lung” was used to analyze USP4 mRNA levels in 3 year-alive or 3 year-dead human lung cancer patients.