Figure 3.

Co-overexpression of activated forms of Notch1 intracellular domain (Nicd) and Ras (NRasV12) or Yes-associated protein (Yap) (YAPS127A) cooperates for the formation of intrahepatic cholangiocarcinoma (iCCA) in mice. A: Experimental study design. B: Survival curve of the various mouse models tested. C: Liver weight/body weight ratio of the mouse models investigated. D: Representative histopathologic features of cholangiocellular lesions developed by a Nicd/Ras mouse 23 weeks post injection (w.p.i.). The lesions are indistinguishable from those developing in Nicd mice. Indeed, both invasive cystadenocarcinomas (CAK) and intrahepatic cholangiocarcinoma (iCCA, also shown in the top middle panel at higher magnification) can be concomitantly observed. The lesions display immunoreactivity for the injected Nicd plasmid (Myc tagged), phosphorylated/activated extracellular signal-regulated kinase (a surrogate marker of Ras/mitogen-activated protein kinase pathway activation), and the biliary markers cytokeratin (CK) 19 and 7. E: Proliferation rate of the tumor lesions developed in Nicd, Nicd/Ras, and Nicd/Yap mice, as assessed by Ki-67 index. Representative Ki-67 staining in the various models is also shown. Data are expressed as means ± SD. ∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001, and ∗∗∗∗P < 0.0001. Scale bars = 100 μm. Original magnification: ×40 (D, top left panel); ×200 (D, all other panels, and E); HE, hematoxylin and eosin.