Journal: Cancer letters
Article Title: SIRPA enhances osteosarcoma metastasis by stabilizing SP1 and promoting SLC7A3-mediated arginine uptake.
doi: 10.1016/j.canlet.2023.216412
Figure Lengend Snippet: Fig. 7. SP1 regulates SLC7A3 expression. A-B. mRNA expression (A) and protein level (B) of SLC7A3 in OS cells with SP1 knockdown or overexpression (n = 3). C. Arginine uptake ratio in OS cells with/without SP1 knockdown upon SLC7A3 overexpression (n = 3). D. Schematic diagram showing possible regulatory sites for SP1 in the SLC7A3 promoter predicted by the JASPAR database (top). Construction of the SLC7A3 luciferase plasmids: wild-type SLC7A3 promoter (WT) and deletion mutants lacking region 1 (ΔRegion 1), region 2 (ΔRegion 2), or both (ΔRegion 1 + 2) (bottom). E. Homology analysis of region 1 and region 2 in the SLC7A3 promoter. F. 143B cells with/without SIRPA knockdown were transfected with plasmids encoding SP1(-500/0)-Luc WT, ΔRegion1, ΔRegion2, and ΔRegion1+2. Then, luciferase levels were measured in extracts after 48 h. G-H. ChIP assay of DNA fragments containing putative region 1 and region 2 within the SLC7A3 promoter region followed by PCR. The SLC7A3 promotor region beyond SP1 regulation (CTR) and the β-actin region (ACTB) were used as negative controls; an anti- histone antibody and rabbit IgG were used as assay controls (G). The histogram shows the relative amount of each DNA fragment binding to SP1 (H). The data are presented as the means±SDs. *P < 0.05, **P < 0.01 by one-way ANOVA.
Article Snippet: The membranes were then incubated with diluted (1:1000) primary antibodies against human ACTB (4970; Cell Signaling Technology), SIRPA (47027; Cell Signaling Technology), SLC7A3 (PA5-103721; Invitrogen), RNF4 (12187; Cell Signaling Technology), ubiquitin (3936; Cell Signaling Technology), SP1 (9389; Cell Signaling Technology), p-Thr278-SP1 (PA5-106039; Invitrogen), p-Thr739-SP1 (PA5-104771; Invitrogen), ERK (4695; Cell Signaling Technology), p-ERK (9101; Cell Signaling Technology), AKT (4691; Cell Signaling Technology), p-AKT (4060; Cell Signaling Technology), β-catenin (8480; Cell Signaling Technology), and p-β-catenin (9567; Cell Signaling Technology).
Techniques: Expressing, Knockdown, Over Expression, Luciferase, Transfection, Binding Assay