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Co-activation of PIK3CA and Yap promotes development of hepatocellular and cholangiocellular tumors in mouse and human liver.

Li X, Tao J, Cigliano A, Sini M, Calderaro J, Azoulay D, Wang C, Liu Y, Jiang L, Evert K, Demartis MI, Ribback S, Utpatel K, Dombrowski F, Evert M, Calvisi DF, Chen X - Oncotarget (2015)

Bottom Line: Activation of the PI3K and Yes-associated protein (Yap) signaling pathways has been independently reported in human hepatocellular carcinoma (HCC).At the molecular level, PIK3CA/Yap tumors were characterized by activation of the mTORC1/2, ERK/MAPK, and Notch pathways.Simultaneous activation of PI3K and Yap pathways frequently occurred in human liver tumor specimens and their combined suppression was highly detrimental for the growth of HCC and CCA cell lines.

View Article: PubMed Central - PubMed

Affiliation: Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China.

ABSTRACT
Activation of the PI3K and Yes-associated protein (Yap) signaling pathways has been independently reported in human hepatocellular carcinoma (HCC). However, the oncogenic interactions between these two cascades in hepatocarcinogenesis remain undetermined. To assess the consequences of the crosstalk between the PI3K and Yap pathways along liver carcinogenesis, we generated a mouse model characterized by combined overexpression of activated mutant forms of PIK3CA (PIK3CAH1047R) and Yap (YapS127A) in the mouse liver using hydrodynamic transfection (PIK3CA/Yap). In addition, suppression of PI3K and Yap pathways was conducted in human HCC and cholangiocarcinoma (CCA) cell lines. We found that concomitant activation of PI3K and Yap pathways triggered rapid liver tumor development in mice. Histologically, tumors were pure HCC, CCA, or mixed HCC/CCA. At the molecular level, PIK3CA/Yap tumors were characterized by activation of the mTORC1/2, ERK/MAPK, and Notch pathways. Simultaneous activation of PI3K and Yap pathways frequently occurred in human liver tumor specimens and their combined suppression was highly detrimental for the growth of HCC and CCA cell lines. In conclusion, our study demonstrates the oncogenic cooperation between PI3K and Yap pathways along liver carcinogenesis. The PIK3CA/Yap mouse represents an important preclinical liver tumor model for the development of novel therapeutics against this malignancy.

No MeSH data available.


Related in: MedlinePlus

Histologic features of liver tumors developed in PIK3CA/Yap mice as assessed by H&E staining(A) Macroscopic appearance of livers from mice injected wih PIK3CAH1047R and YapS127A (PIK3CA/Yap) mice. (B) Kaplan Meier survival curve of wild-type (WT), PIK3CA1047R and PIK3CA/Yap mouse cohort. (C) Preneoplastic lesion consisting of lipid-rich ballooned hepatocytes located around a hepatic vein (V). (D) Pure hepatocellular carcinoma (HCC) characterized by solid and trabecular growth of mildly atypical lipid-rich neoplastic hepatocytes. The arrow indicates a mitosis. (E) Small mixed tumor consisting of both hepatocellular and cholangiocellular components. The hepatocellular part of the tumor consists of large, lipid-rich cells, mainly situated in the outer part of the tumor. Smaller cells with a high nuclear:cytoplasmic ratio, located in the core of the lesion, constitute the cholangiocellular part of the tumor. (F) Mixed HCC/cholangiocarcinoma (CCA) tumor displaying the presence of the hepatocellular component (left part of the picture) that is adjacent to the cholangiocellular component (right part of the picture). (G) Mixed HCC/CCA tumor with hepatocellular and cholangiocellular constituents intermingled with each other, showing moderate cellular atypia and a limited stroma component. The cholangiocellular component forms duct-like structures (asterisks), whereas the hepatocellular component consists of altered, lipid-rich hepatocytes (indicated by arrows). (H) Pure CCA showing significant cellular atypia. Original magnification: 400X.
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Figure 1: Histologic features of liver tumors developed in PIK3CA/Yap mice as assessed by H&E staining(A) Macroscopic appearance of livers from mice injected wih PIK3CAH1047R and YapS127A (PIK3CA/Yap) mice. (B) Kaplan Meier survival curve of wild-type (WT), PIK3CA1047R and PIK3CA/Yap mouse cohort. (C) Preneoplastic lesion consisting of lipid-rich ballooned hepatocytes located around a hepatic vein (V). (D) Pure hepatocellular carcinoma (HCC) characterized by solid and trabecular growth of mildly atypical lipid-rich neoplastic hepatocytes. The arrow indicates a mitosis. (E) Small mixed tumor consisting of both hepatocellular and cholangiocellular components. The hepatocellular part of the tumor consists of large, lipid-rich cells, mainly situated in the outer part of the tumor. Smaller cells with a high nuclear:cytoplasmic ratio, located in the core of the lesion, constitute the cholangiocellular part of the tumor. (F) Mixed HCC/cholangiocarcinoma (CCA) tumor displaying the presence of the hepatocellular component (left part of the picture) that is adjacent to the cholangiocellular component (right part of the picture). (G) Mixed HCC/CCA tumor with hepatocellular and cholangiocellular constituents intermingled with each other, showing moderate cellular atypia and a limited stroma component. The cholangiocellular component forms duct-like structures (asterisks), whereas the hepatocellular component consists of altered, lipid-rich hepatocytes (indicated by arrows). (H) Pure CCA showing significant cellular atypia. Original magnification: 400X.

Mentions: To investigate the genetic crosstalk between the PI3K and Yap signaling pathways in vivo, we overexpressed commonly activated mutant forms of PIK3CA (PIK3CAH1047R, with a HA tag) and Yap1 (YapS127A, with a Flag tag) in the mouse liver using hydrodynamic transfection. As we reported previously [22], overexpression of YapS127A alone did not result in any liver anomaly even after 22.5 weeks post injection (data not shown), whereas overexpression of PIK3CAH1047R (which will be referred to as PIK3CA mouse) resulted in the occurrence of lipid-rich hepatocytes forming clusters throughout the liver parenchyma. Morphologically, these hepatocytes resembled the altered hepatocytes occurring in the livers of mice injected with the myristylated/activated form of AKT1 [23]. However, no tumors developed up to 40 weeks post injection in PIK3CA mice (Supplementary Figure 1A-C). A more detailed description of PIK3CAH1047R mice will be presented elsewhere. In striking contrast, co-expression of PIK3CAH1047R and YapS127A (which will be referred to as PIK3CA/Yap mouse) led to rapid liver tumor development within 12-13 weeks post injection (Figure 1A and B). At the histological level, ~80% of the liver parenchyma from PIK3CA/Yap mice was occupied by tumor lesions, with the remaining liver tissue consisting of lipid-rich hepatocytes (morphologically identical to those detected in PIK3CA mice) and normal liver tissue (Figure 1C-H). Of note, three distinct tumor types were detected in PIK3CA/Yap mice: (i) pure hepatocellular (~40% of all detected tumors), characterized by a solid or macrotrabecular growth pattern, often accompanied by cytoplasmic lipid accumulation and mild cytological atypia; (ii) pure cholangiocellular (~10%), forming primitive ducts and exhibiting stromal reaction; (iii) mixed HCC/CCC (~50% of the tumor lesions), with a hepatocellular component and the other component consisting of spindle-like or oval-cell-like small basophilic cells that resembled CCA-cells (although only rarely forming ductular structures and often lacking desmoplastic stroma) (Figure 1C-H). While pure hepatocellular tumors were generally well-differentiated and rarely showed areas of moderate cellular atypia or necrosis, mixed HCC/CCA and pure cholangiocellular tumors displayed diffuse and moderate to severe atypia. As multiple tumors developed in each PIK3CA/Yap mouse, the three distinct tumor types were detected in each animal investigated.


Co-activation of PIK3CA and Yap promotes development of hepatocellular and cholangiocellular tumors in mouse and human liver.

Li X, Tao J, Cigliano A, Sini M, Calderaro J, Azoulay D, Wang C, Liu Y, Jiang L, Evert K, Demartis MI, Ribback S, Utpatel K, Dombrowski F, Evert M, Calvisi DF, Chen X - Oncotarget (2015)

Histologic features of liver tumors developed in PIK3CA/Yap mice as assessed by H&E staining(A) Macroscopic appearance of livers from mice injected wih PIK3CAH1047R and YapS127A (PIK3CA/Yap) mice. (B) Kaplan Meier survival curve of wild-type (WT), PIK3CA1047R and PIK3CA/Yap mouse cohort. (C) Preneoplastic lesion consisting of lipid-rich ballooned hepatocytes located around a hepatic vein (V). (D) Pure hepatocellular carcinoma (HCC) characterized by solid and trabecular growth of mildly atypical lipid-rich neoplastic hepatocytes. The arrow indicates a mitosis. (E) Small mixed tumor consisting of both hepatocellular and cholangiocellular components. The hepatocellular part of the tumor consists of large, lipid-rich cells, mainly situated in the outer part of the tumor. Smaller cells with a high nuclear:cytoplasmic ratio, located in the core of the lesion, constitute the cholangiocellular part of the tumor. (F) Mixed HCC/cholangiocarcinoma (CCA) tumor displaying the presence of the hepatocellular component (left part of the picture) that is adjacent to the cholangiocellular component (right part of the picture). (G) Mixed HCC/CCA tumor with hepatocellular and cholangiocellular constituents intermingled with each other, showing moderate cellular atypia and a limited stroma component. The cholangiocellular component forms duct-like structures (asterisks), whereas the hepatocellular component consists of altered, lipid-rich hepatocytes (indicated by arrows). (H) Pure CCA showing significant cellular atypia. Original magnification: 400X.
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Related In: Results  -  Collection

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Figure 1: Histologic features of liver tumors developed in PIK3CA/Yap mice as assessed by H&E staining(A) Macroscopic appearance of livers from mice injected wih PIK3CAH1047R and YapS127A (PIK3CA/Yap) mice. (B) Kaplan Meier survival curve of wild-type (WT), PIK3CA1047R and PIK3CA/Yap mouse cohort. (C) Preneoplastic lesion consisting of lipid-rich ballooned hepatocytes located around a hepatic vein (V). (D) Pure hepatocellular carcinoma (HCC) characterized by solid and trabecular growth of mildly atypical lipid-rich neoplastic hepatocytes. The arrow indicates a mitosis. (E) Small mixed tumor consisting of both hepatocellular and cholangiocellular components. The hepatocellular part of the tumor consists of large, lipid-rich cells, mainly situated in the outer part of the tumor. Smaller cells with a high nuclear:cytoplasmic ratio, located in the core of the lesion, constitute the cholangiocellular part of the tumor. (F) Mixed HCC/cholangiocarcinoma (CCA) tumor displaying the presence of the hepatocellular component (left part of the picture) that is adjacent to the cholangiocellular component (right part of the picture). (G) Mixed HCC/CCA tumor with hepatocellular and cholangiocellular constituents intermingled with each other, showing moderate cellular atypia and a limited stroma component. The cholangiocellular component forms duct-like structures (asterisks), whereas the hepatocellular component consists of altered, lipid-rich hepatocytes (indicated by arrows). (H) Pure CCA showing significant cellular atypia. Original magnification: 400X.
Mentions: To investigate the genetic crosstalk between the PI3K and Yap signaling pathways in vivo, we overexpressed commonly activated mutant forms of PIK3CA (PIK3CAH1047R, with a HA tag) and Yap1 (YapS127A, with a Flag tag) in the mouse liver using hydrodynamic transfection. As we reported previously [22], overexpression of YapS127A alone did not result in any liver anomaly even after 22.5 weeks post injection (data not shown), whereas overexpression of PIK3CAH1047R (which will be referred to as PIK3CA mouse) resulted in the occurrence of lipid-rich hepatocytes forming clusters throughout the liver parenchyma. Morphologically, these hepatocytes resembled the altered hepatocytes occurring in the livers of mice injected with the myristylated/activated form of AKT1 [23]. However, no tumors developed up to 40 weeks post injection in PIK3CA mice (Supplementary Figure 1A-C). A more detailed description of PIK3CAH1047R mice will be presented elsewhere. In striking contrast, co-expression of PIK3CAH1047R and YapS127A (which will be referred to as PIK3CA/Yap mouse) led to rapid liver tumor development within 12-13 weeks post injection (Figure 1A and B). At the histological level, ~80% of the liver parenchyma from PIK3CA/Yap mice was occupied by tumor lesions, with the remaining liver tissue consisting of lipid-rich hepatocytes (morphologically identical to those detected in PIK3CA mice) and normal liver tissue (Figure 1C-H). Of note, three distinct tumor types were detected in PIK3CA/Yap mice: (i) pure hepatocellular (~40% of all detected tumors), characterized by a solid or macrotrabecular growth pattern, often accompanied by cytoplasmic lipid accumulation and mild cytological atypia; (ii) pure cholangiocellular (~10%), forming primitive ducts and exhibiting stromal reaction; (iii) mixed HCC/CCC (~50% of the tumor lesions), with a hepatocellular component and the other component consisting of spindle-like or oval-cell-like small basophilic cells that resembled CCA-cells (although only rarely forming ductular structures and often lacking desmoplastic stroma) (Figure 1C-H). While pure hepatocellular tumors were generally well-differentiated and rarely showed areas of moderate cellular atypia or necrosis, mixed HCC/CCA and pure cholangiocellular tumors displayed diffuse and moderate to severe atypia. As multiple tumors developed in each PIK3CA/Yap mouse, the three distinct tumor types were detected in each animal investigated.

Bottom Line: Activation of the PI3K and Yes-associated protein (Yap) signaling pathways has been independently reported in human hepatocellular carcinoma (HCC).At the molecular level, PIK3CA/Yap tumors were characterized by activation of the mTORC1/2, ERK/MAPK, and Notch pathways.Simultaneous activation of PI3K and Yap pathways frequently occurred in human liver tumor specimens and their combined suppression was highly detrimental for the growth of HCC and CCA cell lines.

View Article: PubMed Central - PubMed

Affiliation: Department of Hepatobiliary Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, P.R. China.

ABSTRACT
Activation of the PI3K and Yes-associated protein (Yap) signaling pathways has been independently reported in human hepatocellular carcinoma (HCC). However, the oncogenic interactions between these two cascades in hepatocarcinogenesis remain undetermined. To assess the consequences of the crosstalk between the PI3K and Yap pathways along liver carcinogenesis, we generated a mouse model characterized by combined overexpression of activated mutant forms of PIK3CA (PIK3CAH1047R) and Yap (YapS127A) in the mouse liver using hydrodynamic transfection (PIK3CA/Yap). In addition, suppression of PI3K and Yap pathways was conducted in human HCC and cholangiocarcinoma (CCA) cell lines. We found that concomitant activation of PI3K and Yap pathways triggered rapid liver tumor development in mice. Histologically, tumors were pure HCC, CCA, or mixed HCC/CCA. At the molecular level, PIK3CA/Yap tumors were characterized by activation of the mTORC1/2, ERK/MAPK, and Notch pathways. Simultaneous activation of PI3K and Yap pathways frequently occurred in human liver tumor specimens and their combined suppression was highly detrimental for the growth of HCC and CCA cell lines. In conclusion, our study demonstrates the oncogenic cooperation between PI3K and Yap pathways along liver carcinogenesis. The PIK3CA/Yap mouse represents an important preclinical liver tumor model for the development of novel therapeutics against this malignancy.

No MeSH data available.


Related in: MedlinePlus