The octamer-binding transcription factor 4 (OCT4) is involved in regulating pluripotency and self-renewal maintenance of embryonic stem cells. Recently, misexpression of OCT4 has been also reported in some adult stem as well as cancer cells; a finding which is still controversial. In addition to the previously described spliced variants of the gene (e.g., OCT4A and OCT4B), we have recently identified a novel variant of the gene, designated as OCT4-B1. In this study, we investigated a potential expression and function of OCT4B1 in a series of gastric cancer tissues and a gastric adenocarcinoma cell line, AGS. Using the Taqman real-time PCR approach, we have detected the expression of OCT4B1 in tumors with no or much lower expression in marginal samples of the same patients (p < 0.002). We have also analyzed the effects of OCT4B1 knock-down in AGS cell line treated with specific siRNA directed toward OCT4B1. Our data revealed that interfering with the expression of OCT4B1 caused profound changes in the morphology and cell cycle distribution of the cells. Furthermore, down-regulation of OCT4B1 significantly elevated the relative activity of caspase-3/caspase-7 and the rate of apoptosis in the cells (more than 30%). All together, our findings suggest that OCT4B1 has a potential role in tumorigenesis of gastric cancer and candidates the variant as a new tumor marker with potential value in diagnosis and treatment of gastric cancer.On the basis of the cancer stem cell (CSC) hypothesis, a subpopulation of cells within tumors is responsible for the sustained growth and propagation of tumors. CSCs are also believed to be the main reason for the tumor relapse and resistance to therapy. These cells share various characteristics with normal tissue-specific adult stem cells, including selfrenewal potential. Based on this hypothesis, CSCs are originating either from the dysregulated self-renewal control in normal adult stem cells or through reprogramming of the somatic progenitor or differentiated cells within the tissue. [1][2][3][4][5] The octamer-binding transcription factor 4 (OCT4, also known as OCT3 and POU5F1) belongs to a family of transcription factors containing the POU DNA-binding domain. The encoded protein acts as a master self-renewal regulator in embryonic stem cells and plays a critical role in maintaining the pluripotent state of stem cells. OCT4 expression is strongly repressed following stem cell differentiation. 6-10 Several recent studies have demonstrated the unexpected expression of the OCT4 gene in some human cancer cell lines and tissues, 11-18 including gastric cancer. 19 The human OCT4 gene can potentially encode three spliced variants, designated as OCT4A, OCT4B and the newly discovered OCTB1. 20,21 OCT4A is primarily localized within the nucleus of the embryonic stem cells, where it sustains the selfrenewal and pluripotency properties of the cells. In contrast, OCT4B is mainly located within the cytoplasm of somatic cancer cell lines and apparently lacks any self-renewal regulatory role. 21,22 In ...
Pancreatic duodenum homeobox protein-1 (PDX1) is a master regulatory gene in pancreatic development. Reprogramming of mesenchymal stem cells (MSCs) is a promising tool for producing insulin-producing cells. In this study, lentivirus harboring PDX1 (LV-PDX1) has been used for persistence gene expression in MSCs. The objective of this study was to evaluate the potential of lentivirus to introduce the PDX1 gene into MSCs to produce insulin-secreting cells and apply it for treatment of hyperglycemia in diabetic rats. MSCs were isolated from rat bone marrow, characterized, and transduced by LV-PDX1. Significant expressions of PDX1, neurogenin3, glucagon, glucose transporter2 (Glut2), and insulin were detected by quantitative reverse transcription-polymerase chain reaction (P < 0.05). PDX1 and insulin were detected at the protein level by immunofluorescence analysis. PDX1 could trigger a gene expression cascade that involved pancreatic endocrine differentiation and also revealed the glucose sensing ability by expressing Glut2 in high-glucose medium. The insulin secretion of MSCs(PDX1+) in the high-glucose medium was 1.75-fold higher than that secreted in the low-glucose medium (P < 0.05). MSCs(PDX1+) implanted into diabetic rats could decrease the blood glucose level from 485 mg/dL to the normal level in 3 days. This study showed MSCs(PDX1+) have the potential to be used as a viable resource in cell-based gene therapy of type 1 diabetes.
Purpose The length of GT-repeats polymorphic region in the promoter of human Heme oxygenase-1 gene (HO-1) alters the level of its transcriptional activity in response to oxidative stresses. Decreased level of HO-1 protein in the seminal plasma has been reported to be associated with oligospermia and azoospermia in male infertility. This is the first study to investigate the association between GT-repeats expansion in the promoter of the HO-1 gene and male infertility. Methods The frequencies of different GT-repeats alleles in the promoter of HO-1 gene were determined in 100 cases and 100 normal controls using PCR-PAGE, ABI fragment analysis genotyping and sequencing analysis.Results All alleles were classified into S and L alleles. S alleles were specified as number 0 to 3 with <27 GT-repeats and L alleles were specified as number 4 to 6 with >27 repeats. The L allele frequency was significantly higher among case group (54.5%) than that was obtained in the normal control group (37.5%). Statistical analysis provided a significant relationship between L allele and male infertility (P<0.001). Conclusions This study shows for the first time that GTrepeats expansion in promoter of the HO-1 gene is associated with oligospermia and azoospermia among Iranian infertile cases.
Diabetes mellitus is characterized by autoimmune destruction of pancreatic beta cells, leading to decreased insulin production. Differentiation of mesenchymal stem cells (MSCs) into insulin-producing cells offers novel ways of diabetes treatment. MSCs can be isolated from the human umbilical cord tissue and differentiate into insulin-secreting cells. Human umbilical cord-derived stem cells (hUDSCs) were obtained after birth, selected by plastic adhesion, and characterized by flow cytometric analysis. hUDSCs were transduced with nonintegrated lentivirus harboring PDX1 (nonintegrated LV-PDX1) and was cultured in differentiation medium in 21 days. Pancreatic duodenum homeobox protein-1 (PDX1) is a transcription factor in pancreatic development. Significant expressions of PDX1, neurogenin3 (Ngn3), glucagon, glucose transporter2 (Glut2), and somatostatin were detected by quantitative RT-PCR (P < 0.05). PDX1 and insulin proteins were shown by immunocytochemistry analysis. Insulin secretion of hUDSCs(PDX1+) in the high-glucose medium was 1.8 μU/mL. They were used for treatment of diabetic rats and could decrease the blood glucose level from 400 mg/dL to a normal level in 4 days. In conclusion, our results demonstrated that hUDSCs are able to differentiate into insulin-producing cells by transduction with nonintegrated LV-PDX1. These hUDSCs(PDX1+) have the potential to be used as a viable resource in cell-based gene therapy of type 1 diabetes.
Down syndrome critical region 1 gene (DSCR1) is an anti-angiogenesis gene that inhibits the growth of tumor cells. In this study, the role of autophagy and apoptosis in DSCR1-induced cytotoxicity were investigated in MDA-MB-468 breast cancer cells. Lentivirus vector harboring DSCR1 (LV-DSCR1 + ) was constructed in HEK 293 cells and the optimal dosage of lentivirus vector for infection was determined by the MTT assay. After infection of cells using LV-DSCR1 + , acridine orange and ethidium bromide staining was performed to investigation of apoptosis and autophagy. Expression of DSCR1 and marker genes for angiogenesis (VEGF), apoptosis (Bax and Bcl2) and autophagy (LC3 and Beclin) were determined by Real time PCR. The cellular morphological changes related to apoptosis and autophagy was happened after 48 hours of viral infection. Fragmented bright orange nucleuses and vacuoles were observed due to the cell apoptosis and autophagy after acridine orange and ethidium bromide staining. Upregulation of Bax, Lc3, DSCR1 and Beclin1 and downregulation of Bcl2 and VEGF was detected due to treatment with LV-DSCR1 + . These results demonstrated that LV-DSCR1 + can induce apoptosis and autophagy, therefore suggesting that it may serves as an efficient tool to breast cancer treatment.
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