Cell plasticity regulated by the balance between the mesenchymal to epithelial transition (MET) and the opposite program, EMT, is critical in the metastatic cascade. Several transcription factors (TFs) are known to regulate EMT, though the mechanisms of MET remain unclear. We demonstrate a novel function of two TFs, OVOL1 and OVOL2, as critical inducers of MET in human cancers. Our findings indicate that the OVOL-TFs control MET through a regulatory feedback loop with EMT-inducing TF ZEB1, and the regulation of mRNA splicing by inducing Epithelial Splicing Regulatory Protein 1 (ESRP1). Using mouse prostate tumor models we show that expression of OVOL-TFs in mesenchymal prostate cancer cells attenuates their metastatic potential. The role of OVOL-TFs as inducers of MET is further supported by expression analyses in 917 cancer cell lines, suggesting their role as crucial regulators of epithelial-mesenchymal cell plasticity in cancer.

Proliferation and migration are important biological responses of mesangial cells to injury. Platelet-derived growth factor (PDGF) is a prime candidate to mediate these responses in glomerular disease. PDGF and its receptor (PDGFR) are upregulated in the mesangium during glomerular injury. We have recently shown that PDGF activates phosphatidylinositol 3-kinase (PI-3-kinase) in cultured mesangial cells. The role of this enzyme and other more distal signaling pathways in regulating migration and proliferation of mesangial cells has not yet been addressed. In this study, we used two inhibitors of PI-3-kinase, wortmannin (WMN) and LY-294002, to investigate the role of this enzyme in these processes. Pretreatment of mesangial cells with WMN and LY-294002 dose-dependently inhibited PDGF-induced PI-3-kinase activity assayed in antiphosphotyrosine immunoprecipitates. WMN pretreatment also inhibited the PI-3-kinase activity associated with anti-PDGFRβ immunoprecipitates prepared from mesangial cells treated with PDGF. Pretreatment of the cells with different concentrations of WMN resulted in a dose-dependent inhibition of PDGF-induced DNA synthesis. Both WMN and LY-294002 inhibited PDGF-stimulated migration of mesangial cells in a dose-dependent manner. It has recently been shown that PI-3-kinase physically interacts with Ras protein. Because Ras is an upstream regulator of the kinase cascade leading to the activation of mitogen-activated protein kinase (MAPK), we determined whether activation of PI-3-kinase is necessary for activation of MAPK. Pretreatment of mesangial cells with WMN and LY-294002 significantly inhibited PDGF-induced MAPK activity as measured by immune complex kinase assay of MAPK immunoprecipitates. Furthermore, PD-098059, an inhibitor of MAPK-activating kinase inhibited PDGF-induced MAPK activity and resulted in significant reduction of mesangial cell migration in response to PDGF. These data indicate that MAPK is a downstream target of PI-3-kinase and that both these enzymes are involved in regulating proliferation and migration of mesangial cells.

The ability of a cancer cell to detach from the primary tumor and move to distant sites is fundamental to a lethal cancer phenotype. Metabolic transformations are associated with highly motile aggressive cellular phenotypes in tumor progression. Here, we report that cancer cell motility requires increased utilization of the glycolytic pathway. Mesenchymal cancer cells exhibited higher aerobic glycolysis compared to epithelial cancer cells while no significant change was observed in mitochondrial ATP production rate. Higher glycolysis was associated with increased rates of cytoskeletal remodeling, greater cell traction forces and faster cell migration, all of which were blocked by inhibition of glycolysis, but not by inhibition of mitochondrial ATP synthesis. Thus, our results demonstrate that cancer cell motility and cytoskeleton rearrangement is energetically dependent on aerobic glycolysis and not oxidative phosphorylation. Mitochondrial derived ATP is insufficient to compensate for inhibition of the glycolytic pathway with regard to cellular motility and CSK rearrangement, implying that localization of ATP derived from glycolytic enzymes near sites of active CSK rearrangement is more important for cell motility than total cellular ATP production rate. These results extend our understanding of cancer cell metabolism, potentially providing a target metabolic pathway associated with aggressive disease.

The benefit of liver transplantation (LT) is determined not only by the severity of illness, but also by the likelihood of posttransplantation survival. Current models are unable to accurately predict which patients will have the best posttransplant survival. We hypothesized that the Charlson Comorbidity Index (CCI), which includes nine comorbidities, could be used to predict survival after LT. We performed a retrospective study of 624 patients undergoing LT, with a median follow-up time of 4.3 yr. Data on pretransplant comorbidities were collected, along with potential confounders such as age, gender, etiology, and severity of liver disease. Proportional hazards analysis was performed to determine the independent effect of each variable on posttransplantation survival, and to recalibrate the CCI for use in the liver transplant population. A total of 40% of patients had 1 or more comorbidities prior to transplantation. In the multivariate analysis, CCI was an independent predictor of posttransplantation survival (hazard ratio [HR] 1.21 per unit, P Ͻ 0.001). When the individual components of the CCI were analyzed, coronary disease (HR 2.33), diabetes (HR 1.38), chronic obstructive pulmonary disease (COPD) (HR 2.67), connective tissue disease (HR 2.32), and renal insufficiency (HR 1.61) were all independent predictors of posttransplant survival. The CCI was recalibrated using a simplified weighting system to create the CCI-orthotopic LT (OLT), which improved the likelihood ratio chi-squared value from 15 to 24 for predicting posttransplantation survival. In conclusion, survival after LT is diminished in patients with pretransplantation coronary disease, diabetes, COPD, connective tissue disease, and renal insufficiency. We demonstrate the usefulness of a modified comorbidity index, the CCI-OLT, for predicting posttransplantation survival. Liver Transpl 13:1515Transpl 13: -1520Transpl 13: , 2007