Figure 1.
Effects of CEACAM6 on cell morphology and cytoskeleton in GC cells.
(A) Stable overexpression and suppression of CEACAM6 in GC cells. (B) CEACAM6 expression was analyzed by immunofluorescence, and more CEACAM6 expression was detected in CEACAM6-overexpressing cells than that in control cells (200×). Blue: DAPI; red: CEACAM6. (C) Overexpression of CEACAM6 in SGC-7901 and MKN-45 cells induced a mesenchymal morphology, whereas knockdown of CEACAM6 in MKN-28 cells induced an epithelial morphology (200×). (D) Immunostaining of F-actin in CEACAM6-overexpressing cells and control cells (400×). Red: F-actin; blue: DAPI.
Figure 2.
Expression of CEACAM6 and E-cadherin in gastric tissues.
(A) Negative CEACAM6 expression in non-tumor gastric mucosa. (B, C) Positive or negative CEACAM6 expression in GC samples. (D) Strong positive E-cadherin expression in non-tumorous gastric mucosa. (E, F) Negative or positive E-cadherin expression in GC samples. (G) Negative correlation between CEACAM6 and E-cadherin expression was detected in GC tissues (R = −0.636, P<0.01) (200×).
Table 1.
Association between E-cadherin expression and clinicopathological factors of gastric cancer patients.
Figure 3.
(A, C) The protein levels of EMT markers were assayed by western blot analysis in GC cells with CEACAM6 overexpression or knockdown. (B, D) Relative EMT marker expression in CEACAM6-overexpressing and -silenced GC cells were calculated by gray scale ratio. The results are means of three independent experiments in the bar graphs. *P<0.05, **P<0.01.
Figure 4.
Effect of CEACAM6 on MMP-9 activity, and cell migratory and invasive ability in GC cells.
(A) The supernatant of GC cells was collected after 24 h. Then the MMP-9 activity was examined by gelatin zymography. (B) Relative MMP-9 expression in GC cells. (C, E) Transwell assay. Images show cells that had traveled through the micropore membrane with or without matrigel (200×). (D, F) Histograms showed the numbers of migrating cells and invading cells. The results are means of three independent experiments in the bar graphs. *P<0.05, **P<0.01.
Figure 5.
Effect of CEACAM6 on AKT activity in GC cells.
(A) Western blot analysis showed that overexpression of CEACAM6 increased p-AKT (Ser473) phosphorylation. GAPDH and total AKT were used as loading controls. (B) The quantification of p-AKT (Ser473) expression in GC cells. (C) E-cadherin expression was increased while N-cadherin expression was decreased in CEACAM6-overexpressing GC cells treated with LY294002, a PI3K inhibitor. (D) Relative E-cadherin and N-cadherin expression in CEACAM6-overexpressing and LY294002-treated GC cells were calculated by gray scale ratio. The results are means of three independent experiments in the bar graphs. *P<0.05.
Figure 6.
Effect of CEACAM6 overexpression on peritoneal spread and metastasis.
(A) Increased numbers of metastatic nodules were observed in the SGC-7901-CEACAM6 group than the control group, as indicated by the black arrows. (B) Average number of peritoneal nodules in two groups. More nodules occurred in the SGC-7901-CEACAM6 group than the SGC-7901-NC group.