• BRAF and epithelial-mesenchymal transition in papillary thyroid carcinoma - challenging the roles of Snail and E-Cadherin

      Mitchell, Brendon; Leone, Dominick; Yang, Shi; Khan, Ashraf; Mahalingam, Meera; Dhingra, Jagdish (2016-11-15)
      OBJECTIVE: In papillary thyroid carcinoma (PTC), while the role of BRAF is well established, the contribution of BRAF to epithelial-mesenchymal transition is not. STUDY DESIGN/SETTING: To elucidate the relationship between BRAF, surrogates of epithelial-mesenchymal transition (Snail, E-cadherin) and established histopathologic prognosticators in papillary thyroid carcinoma. SUBJECTS/METHODS: In this IRB approved cross-sectional study, 50 cases of archived annotated PTC samples were retrieved and immunohistochemically stained for Snail and E-cadherin protein. A semi-quantitative scoring system (incorporating proportion and intensity) was utilized. RESULTS: Snail and E-cadherin expression were noted in 44% and 84% of BRAF mutant and, in 29% and 95% of BRAFWT samples, respectively. No statistically significant correlations were noted between Snail, E-cadherin and histopathologic prognosticators. However, a trend was noted between Snail expression and tumor size < 5 cm (P=0.07). Statistically significant differences between BRAF mutant and BRAFWT samples were noted in the following groups: conventional (68% vs. 5%) and tall cell (32% vs. 0%) histopathologic variants, extrathyroidal extension (32% vs. 5%), infiltrative growth pattern (80% vs. 48%), presence of desmoplasia (72% vs. 29%), psammona bodies (48% vs. 10%), and cystic change (32% vs. 5%). Among follicular variant of papillary thyroid carcinoma compared to BRAF mutant samples, BRAFWT samples were more commonly of the encapsulated variety (52% vs. 4%), and microcarcinomas (29% vs. 0%) (P < 0.001 and =0.007, respectively). CONCLUSION: Our findings, supporting the utility of BRAF as a putative therapeutic target in PTC, suggest that the interaction between BRAF and epithelial-mesenchymal transition in papillary thyroid carcinoma is not through induction of the Snail/E-cadherin pathway.
    • Hepatocellular carcinoma is accelerated by NASH involving M2 macrophage polarization mediated by hif-1alphainduced IL-10

      Ambade, Aditya; Satishchandran, Abhishek; Saha, Banishree; Gyongyosi, Benedek; Lowe, Patrick; Kodys, Karen; Catalano, Donna; Szabo, Gyongyi (2016-09-26)
      Obesity-related inflammation promotes cancer development. Tissue resident macrophages affect tumor progression and the tumor micro-environment favors polarization into alternatively activated macrophages (M2) that facilitate tumor invasiveness. Here, we dissected the role of western diet-induced NASH in inducing macrophage polarization in a carcinogen initiated model of hepatocellular carcinoma (HCC). Adult C57BL/6 male mice received diethyl nitrosamine (DEN) followed by 24 weeks of high fat-high cholesterol-high sugar diet (HF-HC-HSD). We assessed liver MRI and histology, serum ALT, AFP, liver triglycerides, and cytokines. Macrophage polarization was determined by IL-12/TNFalpha (M1) and CD163/CD206 (M2) expression using flow cytometry. Role of hif-1alpha-induced IL-10 was dissected in hepatocyte specific hif-1alphaKO and hif-1alphadPA (over-expression) mice. The western diet-induced features of NASH and accelerated HCC development after carcinogen exposure. Liver fibrosis and serum AFP were significantly increased in DEN + HF-HC-HSD mice compared to controls. Western diet resulted in macrophage (F4/80+CD11b+) infiltration to liver and DEN + HF-HC-HSD mice showed preferential increase in M2 macrophages. Isolated hepatocytes from western diet fed mice showed significant upregulation of the hypoxia-inducible transcription factor, hif-1alpha, and livers from hif-1alpha over-expressing mice had increased proportion of M2 macrophages. Primary hepatocytes from wild-type mice treated with DEN and palmitic acid in vitro showed activation of hif-1alpha and induction of IL-10, a M2 polarizing cytokine. IL-10 neutralization in hepatocyte-derived culture supernatant prevented M2 macrophage polarization and silencing hif-1alpha in macrophages blocked their M2 polarization. Therefore, our data demonstrate that NASH accelerates HCC progression via upregulation of hif-1alpha mediated IL-10 polarizing M2 macrophages.
    • Transient RUNX1 Expression during Early Mesendodermal Differentiation of hESCs Promotes Epithelial to Mesenchymal Transition through TGFB2 Signaling

      VanOudenhove, Jennifer J.; Medina, Ricardo F.; Ghule, Prachi N. University of Vermont College of Medicine; Lian, Jane B.; Stein, Janet L.; Zaidi, Sayyed K.; Stein, Gary S. (2016-11-08)
      The transition of human embryonic stem cells (hESCs) from pluripotency to lineage commitment is not fully understood, and a role for phenotypic transcription factors in the initial stages of hESC differentiation remains to be explored. From a screen of candidate factors, we found that RUNX1 is selectively and transiently upregulated early in hESC differentiation to mesendodermal lineages. Transcriptome profiling and functional analyses upon RUNX1 depletion established a role for RUNX1 in promoting cell motility. In parallel, we discovered a loss of repression for several epithelial genes, indicating that loss of RUNX1 impaired an epithelial to mesenchymal transition during differentiation. Cell biological and biochemical approaches revealed that RUNX1 depletion specifically compromised TGFB2 signaling. Both the decrease in motility and deregulated epithelial marker expression upon RUNX1 depletion were rescued by reintroduction of TGFB2, but not TGFB1. These findings identify roles for RUNX1-TGFB2 signaling in early events of mesendodermal lineage commitment.