title: STAT3 is Overactivated in Gastric Cancer Stem-Like Cells.
abstract: OBJECTIVE
  Gastric cancer (GC) is widely associated with chronic inflammation. The pro inflammatory microenvironment provides conditions that disrupt stem/progenitor cell proliferation and differentiation. The signal transducer and activator of transcrip- tion-3 (STAT3) signaling pathway is involved in inflammation and also contributes to the maintenance of embryonic stem cell (ESCs) pluripotency. Here, we have investi- gated the activation status of STAT3 in GC stem-like cells (GCSLCs).
  
  
  METHODS
  In this experimental research, CSLCs derived from the human GC cell line MKN-45 and patient specimens, through spheroid body formation, character- ized and then assayed for the STAT3 transcription factor expression in mRNA and protein level further to its activation.
  
  
  RESULTS
  Spheroid cells showed higher potential for spheroid formation than the pa- rental cells. Furthemore, stemness genes NANOG, c-MYC and SOX-2 were over expressed in spheroids of MKN-45 and in patient samples. In MKN-45 spheroid cells, epithelial mesenchymal transition (EMT) related markers CDH2, SNAIL2, TWIST and VIMENTIN were upregulated (P<0.05), but we observed no change in expression of the E-cadherin epithelial marker. These cells exhibited more resistance to docetaxel (DTX) when compared with parental cells (P<0.05) according to the MTS assay. Al- though immunostaining and Western blotting showed expression of the STAT3 pro- tein in both spheroids and parents, the mRNA level of STAT3 in spheroids was higher than the parents. Nuclear translocation of STAT3 was accompanied by more intensive phospho-STAT3 (p-STAT3) in spheroid structures relative to the parent cells accord- ing to flow cytometry analysis (P<0.05).
  
  
  CONCLUSIONS
  The present findings point to STAT3 over activation in GCSLCs. Com- plementary experiments are required to extend the role of STAT3 in stemness fea- tures and invasion properties of GCSCs and to consider the STAT3 pathway for CSC targeted therapy.
authors: Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors: Monireh
authors: M
authors: Hajimoradi
authors: Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors: Zuhair
authors: Z
authors: Mohammad Hassan
authors: Department of Stem Cells and Developmental Biology, Cell Sciences Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran.
authors: Marzieh
authors: M
authors: Ebrahimi
authors: Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors: Masoud
authors: M
authors: Soleimani
authors: Department of Molecular Medicine, Faculty of Advanced Medical Technologies, Gorgan University of Medical Sciences, Gorgan, Iran.
authors: Mahdieh
authors: M
authors: Bakhshi
authors: Department of Stem Cells and Developmental Biology, Cell Sciences Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran.
authors: Javad
authors: J
authors: Firouzi
authors: Department of Stem Cells and Developmental Biology, Cell Sciences Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran.
authors: Fazel Sahraneshin
authors: FS
authors: Samani
keywords: Cancer Stem Cells; EMT; Gastric Cancer; STAT3; Spheroid