Figure 3.

circDCUN1D4 suppresses the invasion and metastasis of cancer cells in vitro and in vivo

(A and B) Representative images (upper panel) and quantification (lower panel) of Transwell and Matrigel assays, respectively, showing the invasion of A549 cells stably transfected with empty vector (mock) and circDCUN1D4 (mean ± SD, n = 4). Scale bars, 100 μm. (C) Cell migration in real time was analyzed by the xCELLigence RTCA (mean ± SD, n = 4). (D) Representative images of the wound-healing assay showing the metastasis of A549 cells stably transfected with empty vector (mock) and circDCUN1D4 (mean ± SD, n = 4). Scale bar, 100 μm. (E) Representative images (left panel) and quantification (right panel) of the immunofluorescence staining assay showing the expression of E-cadherin (E-cad) in A549 and H1299 cells stably transfected with mock, circDCUN1D4, scramble shRNA (sh-scb), or sh-circDCUN1D4 vectors (mean ± SD, n = 4). (F) Western blot indicating the expression of N-cadherin (N-cad), E-cad, vimentin, and GAPDH in total lysates of A549 and H1299 cells stably transfected with mock, circDCUN1D4, sh-scb, or sh-circDCUN1D4 vectors. (G) Images of dissected mouse lungs after tail-vein injection of A549 cells stably transfected with mock and circDCUN1D4 vectors (n = 4 for each group). (H) H&E staining of pathological sections (left panel) and the quantification of metastasis count (right panel). Student’s t test and analysis of variance compared the differences in (A–D) and (H). ∗p < 0.05 versus mock or sh-scb.