Fig 2: LMO4 is a direct target gene of miR-139-5p. (a) Schematic diagram showing miR-139-5p putative binding sites in LMO4 3'-UTR. (b) Interaction between the miR-139-5p and LMO4 3'-UTR was determined using a dual-luciferase reporter assay. (c) Reverse transcription-quantitative PCR was used to estimate LMO4 mRNA expression in ARPE-19 cells under NG or HG during various time points. (d) Western blotting was used to assess LMO4 protein expression in ARPE-19 cells treated with HG at different hours. A total of three independent experiments were carried out. Error bars represent the mean ± SD of =3 experiments. *P < 0.05. miR: microRNA; LMO4: LIM-only factor 4; UTR: untranslated region.

Fig 3: LMO4 is a target gene of miR-573 in breast cancer cells. (A) A putative seed sequence between LMO4 mRNA 3'UTR and miR-573 was predicted using miRanda software. (B) Expression of LMO4 was analyzed by immunohistochemistry (IHC) in 10 breast cancer specimens. Positive LMO4 expression was observed in 9 out of 10 tumors. (C) Association between LMO4 expression and overall survival of patients with breast cancer was analyzed using GSE42958 dataset (n=104). (D) Transfection of miR-573 inhibitor increased LMO4 mRNA levels and miR-573 mimic decreased LMO4 mRNA levels. (E) Transfection of miR-573 inhibitor increased LMO4 protein levels and miR-573 mimic decreased LMO4 protein levels. (F) Quantification of LMO4 protein expression in E. (G) Dual luciferase assay showed that relative luciferase activity was reduced in MDA-MB-231 cells co-transfected with LMO4 3'UTR-WT and miR-573 mimic. (H) Dual luciferase assay showed that relative luciferase activity was reduced in MDA-MB-468 cells co-transfected with LMO4 3'UTR-WT and miR-573 mimic. **P<0.01; ***P<0.001. LMO4, LIM domain only 4; WT, wild-type; Mut, mutant-type.

Fig 4: LMO4 is a target of miR-637, and circLDLR regulates LMO4 via miR-637 in PTC cells. (a) The predicted binding sites of miR-637 on LMO4 sequences. (b) Luciferase activity detection in TPC-1 and IHH-4 cells cotransfected with the reporter plasmid and the indicated miRNAs using the dual-luciferase reporter assay. (c) qRT-PCR analysis of miR-637 and LMO4 expression in TPC-1 and IHH-4 cells pulled down by Anti-Ago2 or Anti-IgG. (d) Western blot analysis of LMO4 level in TPC-1 and IHH-4 cells transfected with NC, miR-637, circ-NC + miR-637, and circLDLR + miR-637. (e, f) Level detection of LMO4 in 45 PTC tissues and matched normal tissues with qRT-PCR and western blot. (g, h) Correlation analysis between LMO4 and circLDLR or miR-637 in PTC tissues with Pearson correlation analysis. (i) Level detection of LMO4 in PTC cell lines (TPC-1 and IHH-4) and normal Nthy-ori 3-1 cell lines with western blot. ***P < 0.001.

Fig 5: CircLDLR knockdown impedes the growth of xenograft tumors in vivo. TPC-1 cells stably transfected with sh-circLDLR or sh-NC were subcutaneously injected into the flanks of the nude mice to establish xenograft models. (a, b) The detection of the size and weight of xenograft tumors. (c, d) qRT-PCR analysis of circLDLR and miR-637 levels in tumor masses. (e) Western blot analysis of LMO4, PCNA, and C-caspase3 levels in in tumor masses. **P < 0.01, ***P < 0.001.