Wnt-pathway activation in two molecular classes of hepatocellular carcinoma and experimental modulation by sorafenib.
OBJECTIVE
Hepatocellular carcinoma (HCC) is a heterogeneous cancer with active Wnt signaling. Underlying biologic mechanisms remain unclear and no drug targeting this pathway has been approved to date. We aimed to characterize Wnt-pathway aberrations in HCC patients, and to investigate sorafenib as a potential Wnt modulator in experimental models of liver cancer.


METHODS
The Wnt-pathway was assessed using mRNA (642 HCCs and 21 liver cancer cell lines) and miRNA expression data (89 HCCs), immunohistochemistry (108 HCCs), and CTNNB1-mutation data (91 HCCs). Effects of sorafenib on Wnt signaling were evaluated in four liver cancer cell lines with active Wnt signaling and a tumor xenograft model.


RESULTS
Evidence for Wnt activation was observed for 315 (49.1%) cases, and was further classified as CTNNB1 class (138 cases [21.5%]) or Wnt-TGFβ class (177 cases [27.6%]). CTNNB1 class was characterized by upregulation of liver-specific Wnt-targets, nuclear β-catenin and glutamine-synthetase immunostaining, and enrichment of CTNNB1-mutation-signature, whereas Wnt-TGFβ class was characterized by dysregulation of classical Wnt-targets and the absence of nuclear β-catenin. Sorafenib decreased Wnt signaling and β-catenin protein in HepG2 (CTNNB1 class), SNU387 (Wnt-TGFβ class), SNU398 (CTNNB1-mutation), and Huh7 (lithium-chloride-pathway activation) cell lines. In addition, sorafenib attenuated expression of liver-related Wnt-targets GLUL, LGR5, and TBX3. The suppressive effect on CTNNB1 class-specific Wnt-pathway activation was validated in vivo using HepG2 xenografts in nude mice, accompanied by decreased tumor volume and increased survival of treated animals.


CONCLUSIONS
Distinct dysregulation of Wnt-pathway constituents characterize two different Wnt-related molecular classes (CTNNB1 and Wnt-TGFβ), accounting for half of all HCC patients. Sorafenib modulates β-catenin/Wnt signaling in experimental models that harbor the CTNNB1 class signature.
Mount Sinai Liver Cancer Program, Mount Sinai School of Medicine, New York, NY 10029, USA.
Anja
A
Lachenmayer
Clara
C
Alsinet
Radoslav
R
Savic
Laia
L
Cabellos
Sara
S
Toffanin
Yujin
Y
Hoshida
Augusto
A
Villanueva
Beatriz
B
Minguez
Philippa
P
Newell
Hung-Wen
HW
Tsai
Jordi
J
Barretina
Swan
S
Thung
Stephen C
SC
Ward
Jordi
J
Bruix
Vincenzo
V
Mazzaferro
Myron
M
Schwartz
Scott L
SL
Friedman
Josep M
JM
Llovet
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D016000:Cluster Analysis; D005260:Female; D020869:Gene Expression Profiling; D023281:Genomics; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D010671:Phenylurea Compounds / Q000494:pharmacology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D015203:Reproducibility of Results; D000077157:Sorafenib; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism*; D060449:Wnt Signaling Pathway / Q000187:drug effects*; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; C495270:CTNNB1 protein, human; D010671:Phenylurea Compounds; D047428:Protein Kinase Inhibitors; D016212:Transforming Growth Factor beta; D051153:Wnt Proteins; D051176:beta Catenin; D009536:Niacinamide; D000077157:Sorafenib