Epithelial-Mesenchymal Transition (EMT) of K19 Structures within the Stromal Compartment of HCV Cirrhosis Parallels Hepatocarcinogenesis
JK Lennerz, WC Chapman, EM Brunt. Washington University, St.Louis; Massachusetts General Hospital, Boston
Background: The stromal compartment of cirrhosis harbors vascular channels, inflammatory and fibrogenic cells, and K19 positive epithelial structures. We documented progressive loss of K19 ductular structures in progression from cirrhotic (CN) to dysplastic (DN) to hepatocellular carcinoma (HCC) [LabInv 2009; 89:314A]. The aim is to assess possible EMT.
Design: Sections from 36 HCV cirrhotic explants with HCC were studied for features diagnostic of EMT: a) co-expression of S100A4 or SNAIL with loss of membranous ECadh, or b) nuclear pSMAD concurrent with cytoplasmic SMAD2/3 and TGFß1R. Marker quantification of K19 profiles was performed in randomly chosen perinodular sectors that covered at least 25% of the stromal circumference.
Results: Quantification of K19 structures shows significant differences (*P<0.001; Mann-Whitney U test) between CN and DN (Table). Co-localized EMT markers were found within single cells of most K19 structures surrounding CN. EMT markers decreased in conjunction with both loss of stromal K19 structures as well as malignant progression of the nodule itself. Correlating with the fewer K19 cells in stroma around DN several marker proportions are reversed (ECadh>Smad2/3>S100A4>pSmad>Snail>TGFßR1) compared to CN (ECadh>Smad2/3>TGFßR1>Snail>pSmad>S100A4).
Conclusions: Perinodular stromal K19 loss is associated with alterations of TGFß1R, Smad2/3 and other markers of EMT. K19 loss parallels the progression of intranodular hepatocyte transformation from cirrhosis to DN to HCC. Together, these findings strongly suggest altered paracrine signaling at the interface of hepatocellular nodules and surrounding stroma.
|CN (n=71)||DN (n=45)||HCC (n=54)|
|K19 profiles (s)||408.9±23.7* (36)||106.3±14.6* (27)||1.52±0.2 (30)|
|K19 cells (in n sectors)||2088±262* (27)||300±44* (30)||2.4±0.3 (27)|
|Ecadh+ (%;s)||51±4 (∼80%;54)||7±0.6 (∼78%;54)||(-) (-;20)|
|S100A4+ (%;s)||5.2±0.4 (∼10%;27)||3.9±0.3 (∼65%;27)||(-) (-;20)|
|Snail+ (%;s)||25.8±2.3 (∼34%;27)||5.9±0.6 (∼52%;27)||(-) (-;20)|
|TGFβR1+ (%;s)||40.6±3.6 (∼48%;27)||1.4±0.2 (∼15%;27)||(-) (-;20)|
|Smad2/3+ (%;s)||58.3±5 (∼68%;27)||6.8±0.5 (∼74%;27)||(-) (-;20)|
|pSmad+ (%;s)||22.9±2 (∼27%;27)||9.2±0.8 (∼60%;27)||(-) (-;20)|