Fig. 1: Abolishment of the NELF complex impairs tumorigenic properties.

a Western blot analysis of NELF-A and NELF-E in non-tumorigenic breast epithelial cell line MCF10A, as well as in different breast cancer cell lines T-47D (ER⁺, PR⁺), SK-BR-3 (HER2⁺), MCF7 (ER⁺), BT-474 (HER2⁺), BT-549 (triple-negative), MDA-MB-231 (triple-negative), and SUM159 (triple-negative). β-actin was used as the loading control. b, c Left: MCF7 cells (n = 3) and BT-549 cells (n = 4) were transfected with non-targeting siRNA (‘scrambled, siSCR’) and siRNAs targeting NELF-A and NELF-E, respectively, followed by western blot analysis. GAPDH was used as the loading control. Right: Representative images and quantification of soft agar assays. d Left: Western blot analysis of NELF-A, NELF-E, NELF-B, and NELF-C/D in WT and NELF-A/NELF-E KO SUM159 cells. β-actin was used as the loading control. Right: Representative images and quantification of soft agar assays (n = 4). e 5 × 10⁶ WT, NELF-A KO, and NELF-E KO SUM159 cells were injected into the mammary fat pads of NOD/SCID mice, respectively. Tumor volume was measured every 3 days after the tumor was palpable; mean ± SEM, n = 4/group. f Left: Tumors harvested from WT, NELF-A KO, and NELF-E KO groups; Right: Quantification of tumor weights; mean ± SEM, n = 4/group. Blots and images are representative of at least three independent experiments. Data in (b–d) are presented as mean ± SD. p-values are determined by a two-tailed Student’s t-test. Source data are provided as a Source Data file.