The topographical environment, which mimics the stem cell niche, provides mechanical cues to regulate the differentiation of mesenchymal stem cells (MSC). Diverse topographical variations have been engineered to investigate cellular responses; however, the types of mechanical parameters that affect cells, and their underlying mechanisms remain largely unknown. In this study, we screened nanotopological pillars with size gradient to activate transcriptional coactivator with PDZ binding motif (TAZ), which stimulates osteogenesis of MSC. We observed that a nanotopological plate, 70 nm in diameter, significantly induces osteogenic differentiation with the activation of TAZ. TAZ activation via the nanotopological plate was mediated by actin polymerization and Rho signaling, as evidenced by the cytosolic localization of TAZ under F-actin or Rho kinase inhibitor. The FAK and MAPK pathways also play a role in TAZ activation by the nanotopological plate because the inhibitor of ERK and JNK blocked nanopattern plate induced osteogenic differentiation. Taken together, these results indicate that nanotopology regulates cell differentiation through TAZ activation.
Insulin regulates blood glucose levels by binding its receptor and stimulating downstream proteins through the insulin receptor substrate (IRS). Impaired insulin signalling leads to metabolic syndrome, but the regulation of this process is not well understood. Here, we describe a novel insulin signalling regulatory pathway involving TAZ. TAZ upregulates IRS1 and stimulates Akt- and Glut4-mediated glucose uptake in muscle cells. Muscle-specific TAZ-knockout mice shows significantly decreased Irs1 expression and insulin sensitivity. Furthermore, TAZ is required for Wnt signalling-induced Irs1 expression, as observed by decreased Irs1 expression and insulin sensitivity in muscle-specific APC- and TAZ-double-knockout mice. TAZ physically interacts with c-Jun and Tead4 to induce Irs1 transcription. Finally, statin administration decreases TAZ, IRS1 level and insulin sensitivity. However, in myoblasts, the statin-mediated decrease in insulin sensitivity is counteracted by the expression of a constitutively active TAZ mutant. These results suggest that TAZ is a novel insulin signalling activator that increases insulin sensitivity and couples Hippo/Wnt signalling and insulin sensitivity.
Purpose: The present study evaluated the prognostic significance of apoptosis-related proteins, p53, Bcl-2, Bax, and galectin-3 in patients with locally advanced esophageal cancer treated with definitive chemoradiotherapy. Experimental Design: A total of 63 patients with locally advanced esophageal cancer (squamous cell carcinoma: 62; adenocarcinoma: 1; stages II-IV) were treated with definitive chemoradiotherapy using 5-fluorouracil and cisplatin combined with radiotherapy. Pretreatment tumor biopsy specimens were analyzed for p53, Bcl-2, Bax, and galectin-3 expression by immunohistochemistry. Results: High expression of Bax, p53, Bcl-2, and galectin-3 was observed in 67%, 47%, 24%, and 29% of patients, respectively. The median overall survival (OS) of total patients was 14 months with 16% of 3-year OS. High expression of p53, Bcl-2, and galectin-3 did not show correlation with clinicopathologic characteristics, including patient outcome. Low expression of Bax was significantly correlated with lack of clinical complete response (P = 0.023). Low expression of Bax was also associated with poor OS (median, 8 months versus 16 months; P = 0.0008) in univariate analysis. In multivariate analysis, low expression of Bax was the most significant independent predictor of poor OS (P = 0.009), followed by low dose intensity of cisplatin and lack of clinical complete response. Conclusions: Low expression of Bax was significantly associated with the poor survival of patients with locally advanced esophageal cancer treated with chemoradiotherapy using 5-fluorouracil and cisplatin. Immunohistochemical staining for Bax with a pretreatment biopsy specimen might be useful to select the optimal treatment options for these patients.
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