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]
Materials and Methods: In this experimental research, CSLCs derived from the human GC cell line MKN-45 and patient specimens, through spheroid body formation, characterized 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 parental 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. Although immunostaining and Western blotting showed expression of the STAT3 protein 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 according to flow cytometry analysis [P<0.05]
Conclusion: The present findings point to STAT3 over activation in GCSLCs. Complementary experiments are required to extend the role of STAT3 in stemness features and invasion properties of GCSCs and to consider the STAT3 pathway for CSC targeted therapy
ABSTRACT
Pancreatic stroma plays an important role in the induction of pancreatic cells by the use of close range signaling. In this respect, we presume that pancreatic mesenchymal cells [PMCs] as a fundamental factor of the stromal niche may have an effective role in differentiation of umbilical cord blood cluster of differentiation 133[+] [UCB-CD133[+]] cells into newly-formed beta-cells in vitro. This study is an experimental research. The UCB-CD133[+] cells were purified by magnetic activated cell sorting [MACS] and differentiated into insulin producing cells [IPCs] in co-culture, both directly and indirectly with rat PMCs. Immunocytochemistry and enzyme linked immune sorbent assay [ELISA] were used to determine expression and production of insulin and C-peptide at the protein level. Our results demonstrated that UCB-CD133[+] differentiated into IPCs. Cells in islet-like clusters with [out] co-cultured with rat pancreatic stromal cells produced insulin and C-peptide and released them into the culture medium at the end of the induction protocol. However they did not respond well to glucose challenges. Rat PMCs possibly affect differentiation of UCB-CD133[+] cells into IPCs by increasing the number of immature beta-cells
ABSTRACT
Objective: Genetic modification of human embryonic stem cells [hESCs] is critical for their extensive use as a fundamental tool for cell therapy and basic research. Despite the fact that various methods such as lipofection and electroporation have been applied to transfer the gene of interest [GOI] into the target cell line, however, there are few reports that compare all parameters, which influence transfection efficiency. In this study, we examine all parameters that affect the efficiency of electroporation and lipofection for transient and long-term gene expression in three different cell lines to introduce the best method and determinant factor
Materials and Methods: In this experimental study, both electroporation and lipofection approaches were employed for genetic modification. pCAG-EGFP was applied for transient expression of green fluorescent protein in two genetically different hESC lines, Royan H5 [XX] and Royan H6 [XY], as well as human foreskin fibroblasts [hFF]. For long-term EGFP expression VASA and OLIG2 promoters [germ cell and motoneuron specific genes, respectively], were isolated and subsequently cloned into a pBluMAR5 plasmid backbone to drive EGFP expression. Flow cytometry analysis was performed two days after transfection to determine transient expression efficiency. Differentiation of drug resistant hESC colonies toward primordial germ cells [PGCs] was conducted to confirm stable integration of the transgene
Results: Transient and stable expression suggested a variable potential for different cell lines against transfection. Analysis of parameters that influenced gene transformation efficiency revealed that the vector concentrations from 20-60 Mug and the density of the subjected cells [5×105 and 1×106 cells] were not as effective as the genetic background and voltage rate. The present data indicated that in contrast to the circular form, the linearized vector generated more distinctive drug resistant colonies
Conclusion: Electroporation was an efficient tool for genetic engineering of hESCs compared to the chemical method. The genetic background of the subjected cell line for transfection seemed to be a fundamental factor in each gene delivery method. For each cell line, optimum voltage rate should be calculated as it has been shown to play a crucial role in cell death and rate of gene delivery
ABSTRACT
Hepatitis C virus [HCV] is one of the most relevant persistent infections afflicting the human population. Control of viral replication in HCV infection has been associated with the cellular component of the host immune response. Several mechanisms have been proposed to explain this abnormal immune response, among them an altered activity of regulatory T cells [Tregs] being the most recently postulated. As the first report, in the present study the ability of HCV-core antigen in increase the frequency of natural Tregs [nTregs] in the mixed population of PBMCs was evaluated. Peripheral blood mononuclear cells [PBMCs] from chronic HCV infected patients [n=19] and normal controls [n=6] were analyzed to study the effect of HCV-core antigen in frequency of HCV specific nTregs. For this, PBMCs of different groups were isolated, cultured and stimulated with core antigen. Then an in-house triple-stain flowcytometric method was used to investigate the frequency of nTregs. The results showed that, following incubation with HCV-core Ag, a population of nTregs was increased but, in negative controls the number of nTregs did not increase. The present data supporting the idea that nTregs are able to respond specifically to HCV antigen suggests that Tregs could contribute to an inadequate response against the HCV infection, leading to chronic infection and supports the view that specific natural Tregs may be implicated in host immune tolerance during HCV infection. It is reasonable that HCV vaccine candidates avoid epitopes that lead to strong nTregs stimulation