Purpose EMT has been associated with metastatic spread and EGFR inhibitor resistance. We developed and validated a robust 76-gene EMT signature using gene expression profiles from four platforms using NSCLC cell lines and patients treated in the BATTLE study. Methods We conducted an integrated gene expression, proteomic, and drug response analysis using cell lines and tumors from NSCLC patients. A 76-gene EMT signature was developed and validated using gene expression profiles from four microarray platforms of NSCLC cell lines and patients treated in the BATTLE (Biomarker-integrated Approaches of Targeted Therapy for Lung Cancer Elimination) study, and potential therapeutic targets associated with EMT were identified. Results Compared with epithelial cells, mesenchymal cells demonstrated significantly greater resistance to EGFR and PI3K/Akt pathway inhibitors, independent of EGFR mutation status, but more sensitivity to certain chemotherapies. Mesenchymal cells also expressed increased levels of the receptor tyrosine kinase Axl and showed a trend towards greater sensitivity to the Axl inhibitor SGI-7079, while the combination of SGI-7079 with erlotinib reversed erlotinib resistance in mesenchymal lines expressing Axl and in a xenograft model of mesenchymal NSCLC. In NSCLC patients, the EMT signature predicted 8-week disease control in patients receiving erlotinib, but not other therapies. Conclusion We have developed a robust EMT signature that predicts resistance to EGFR and PI3K/Akt inhibitors, highlights different patterns of drug responsiveness for epithelial and mesenchymal cells, and identifies Axl as a potential therapeutic target for overcoming EGFR inhibitor resistance associated with the mesenchymal phenotype

Mesenchymal stem cells (MSCs) have been considered as an attractive tool for the therapy of diseases. Exosomes excreted from MSCs can reduce myocardial ischemia/reperfusion damage and protect against acute tubular injury. However, whether MSC-derived exosomes can relieve liver fibrosis and its mechanism remain unknown. Previous work showed that human umbilical cord-MSCs (hucMSCs) transplanted into acutely injured and fibrotic livers could restore liver function and improve liver fibrosis. In this study, it was found that transplantation of exosomes derived from hucMSC (hucMSC-Ex) reduced the surface fibrous capsules and got their textures soft, alleviated hepatic inflammation and collagen deposition in carbon tetrachloride (CCl 4 )-induced fibrotic liver. hucMSC-Ex also significantly recovered serum aspartate aminotransferase (AST) activity, decreased collagen type I and III, transforming growth factor (TGF)-b1 and phosphorylation Smad2 expression in vivo. In further experiments, we found that epithelial-to-mesenchymal transition (EMT)-associated markers E-cadherin-positive cells increased and N-cadherin-and vimentin-positive cells decreased after hucMSC-Ex transplantation. Furthermore, the human liver cell line HL7702 underwent typical EMT after induction with recombinant human TGF-b1, and then hucMSC-Ex treatment reversed spindle-shaped and EMT-associated markers expression in vitro. Taken together, these results suggest that hucMSC-Ex could ameliorate CCl 4 -induced liver fibrosis by inhibiting EMT and protecting hepatocytes. This provides a novel approach for the treatment of fibrotic liver disease.

Low environmental temperatures promote anthocyanin accumulation and fruit colouration by up-regulating the expression of genes involved in anthocyanin biosynthesis and regulation in many fruit trees. However, the molecular mechanism by which fruit trees regulate this process in response to low temperature (LT) remains largely unknown. In this study, the cold-induced bHLH transcription factor gene MdbHLH3 was isolated from an apple tree and was found to interact physically and specifically through two regions (amino acids 1-23 and 186-228) at the N terminus with the MYB partner MdMYB1 (allelic to MdMYB10). Subsequently, MdbHLH3 bound to the promoters of the anthocyanin biosynthesis genes MdDFR and MdUFGT and the regulatory gene MdMYB1 to activate their expression. Furthermore, the MdbHLH3 protein was post-translationally modified, possibly involving phosphorylation following exposure to LTs, which enhanced its promoter-binding capacity and transcription activity. Our results demonstrate the molecular mechanism by which MdbHLH3 regulates LT-induced anthocyanin accumulation and fruit colouration in apple.