Fig. 7. DIAPH1-AS1 confers NPC progression via MTDH-LASP1 complex.

A, B The expression levels of MTDH, LASP1, and DIAPH1-AS1 in NPC cells with or without DIAPH1-AS1 (A) or MTDH (B) silencing were detected using western blotting (left) and qRT-PCR (right). C Western blotting analysis of MTDH and LASP1 levels in HONE-1 cells with or without DIAPH1-AS1 silencing, and treated with MG132 (10 mmol/l) for 24 h or transfected with MTDH overexpression vectors. D SUNE-1 and HONE-1 cells co-transfected with DIAPH1-AS1 overexpressing vector and si-MTDH or the corresponding negative control, were treated with 50 µg/ml cycloheximide (CHX) for the indicated time points and harvested for western blotting analysis to assess the protein stability and half-life of LASP1. E The immunoprecipitation (IP) experiment with anti-LASP1 antibodies, followed by western blotting with anti-ubiquitin antibodies to detect ubiquitinated LASP1 in HONE-1 cells co-transfected as indicated. F–I The effect of the ectopic expression of LASP1 to rescue the si-DIAPH1-AS1-mediated downregulation of NPC cell proliferation and metastasis. SUNE-1 and HONE-1 cells were co-transfected with si-DIAPH1-AS1 and LASP1 overexpressing vectors or the corresponding negative control. Then CCK-8 assays (F) and colony formation assays (G) for cell proliferation and Transwell assays for cell invasion (H, I) were performed. Scale bar: 200 μm. J A graphic illustration of WTAP promoting tumor growth and metastasis of NPC by modulating lncRNA DIAPH1-AS1 m6A modification and disrupting its RNA decay. Data are presented as the mean ± SD. *P < 0.05, **P < 0.01. The experiments were repeated at least three times independently.