Figure 11.

PTK7 overexpression promotes extrahepatic metastasis to the lung of liver-engrafted HCC cells, and PTK7 knockout suppresses the ability of cells to extravasate into the lung. (A) In vivo detection of luciferase-induced luminescence of tumor nodules and images of livers dissected from nude mice 8 weeks after orthotopic liver injection of MHCC97L overexpressing cells. (B) External morphology of HCC nodules formed in the livers of nude mice 8 weeks after orthotopic liver injection of MHCC97L-overexpressing cells. (C) H&E-stained tissue sections of lungs dissected from the orthotopic injection model showing the formation of lung metastases (indicated by white arrows). The number of discernible metastases formed in the lungs of mice injected with MHCC97L-overexpressing cells was counted and compared using the Student t test. (D) H&E-stained tissue sections of livers dissected from the orthotopic injection model showing different features of the tumor boundary. The presence of microsatellites is indicated by black arrows. (E) A summary table of the parameters related to metastatic aggressiveness of the tumors in the orthotopic injection model. (F) Murine RIL175 cells with Ptk7 depleted by CRISPR-Cas9–mediated knockout were injected into nude mice through the tail vein to observe lung metastasis formation. Luciferase-induced luminescence of tumor nodules developed from RIL175 cells was detected using in vivo imaging 7 days after tail vein injection. The total detectable radiance was compared between the control and Ptk7-knockout groups using 1-way analysis of variance. Ctrl, control; OE, overexpression. P values (∗P < .05, ∗∗P < .01, ∗∗∗P < .001).