Journal: Redox Biology
Article Title: SMURF2 attenuates NRF2-driven tumor progression by acting as a nuclear brake on NRF2 during cellular stress
doi: 10.1016/j.redox.2026.104102
Figure Lengend Snippet: SMURF2 promotes cell apoptosis through NRF2 inactivation. (A) LN229 cells were transfected with HA, HA-SMURF2, Myc-NRF2 or HA-SMURF2 + Myc-NRF2 and subsequent treatment with MG132 (10 μM, 12 h), H 2 O 2 (200 μM, 2 h), or LPS (100 ng/mL, 12 h). Representative IF images of the colocalization of ub and p62. Nuclei stained with DAPI. (B and C) HEK293T cells were transfected with empty vector or Myc-NRF2, followed by Flag or Flag-SMURF2 expression. Western blotting was performed using indicated antibodies (B). qRT-PCR was performed using primers specific for indicated genes (C). The fold change in expression in Flag-SMURF2 overexpressing samples was calculated relative to control samples. (D) HEK293T cells were first transfected with NRF2 siRNA for 48 h, followed by transfection with either Myc-NRF2-WT or Myc-NRF2-K555R, and subsequently transfected with Flag or Flag-SMURF2.Western blotting was performed using indicated antibodies. (E) LN229 cells were transfected with SMURF2 siRNA or scramble siRNA oligos for 48 h, followed by treatment with PBS or H 2 O 2 (200 μM, 2 h). Cells were then stained with 2,7-Dichlorodihydrofluorescein diacetate (DCFH-DA, 10 μM) and the ROS level was detected by flow cytometry. (F) Quantification of relative ROS fluorescence intensity in LN229 cells with SMURF2 knockdown or HA-SMURF2 overexpression. (G and H) LN229 cells were transfected with SMURF2 siRNA or scramble siRNA oligos for 48 h or transfected with HA or HA-SMURF2, followed by treatment with PBS or H 2 O 2 (200 μM, 2 h). Cells were then stained with Annexin-V/propidium iodide (PI), and apoptotic cells were detected by flow cytometry (G). Quantification of apoptosis in LN229 cells with SMURF2 knockdown or HA-SMURF2 overexpression (H). (I) HEK293T cells were transfection with Flag or Flag-SMURF2, and subsequent treatment with or without MG132 (10 μM, 12 h), H 2 O 2 (200 μM, 2 h), or LPS (100 ng/ml, 12 h). Western blotting was performed using indicated antibodies. (J and K) HEK293T cells were transfected with empty vector and Myc-NRF2 (J) or Myc-NRF2-WT, Myc-NRF2-K555R (K), followed by Flag or Flag-SMURF2 expression. Cells were subsequently treated with MG132 (10 μM, 12 h), H 2 O 2 (200 μM, 2 h), or LPS (100 ng/mL, 12 h). Western blotting was performed using indicated antibodies. (L) The shSMURF2 and shPLKO cells were treated with or without LPS (100 ng/mL, 12 h) and cultured for 14 days. Colony formation assay was performed for cells. (M) The representative images of shSMURF2 and shPLKO patient-derived cells formed tumors in nude mice with or without LPS (10 mg/kg). (N) The graph showed the quantified data of tumor weight. (O) Immunohistochemistry (IHC) analysis of tumor tissue slides with antibodies against Ki67. Nucleus was stained by hematoxylin. Scale bar, 50 μm (P) The proposed model indicates that SMURF2 promotes cell apoptosis through NRF2 inactivation. Data were presented as the mean ± SD from three independent experiments. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001. Scale bar: 10 μm, Scale bar, 50 μm.
Article Snippet: The human glioblastoma cell lines LN229 and human embryonic kidney 293T (HEK293T) cell lines were purchased from the American Type Culture Collection (ATCC).
Techniques: Transfection, Staining, Plasmid Preparation, Expressing, Western Blot, Quantitative RT-PCR, Control, Flow Cytometry, Fluorescence, Knockdown, Over Expression, Cell Culture, Colony Assay, Derivative Assay, Immunohistochemistry