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Summary Hydroxyurea (HU) is a drug used for the treatment of haemoglobinopathies. Hydroxyurea functions by upregulating γ‐globin transcription and fetal haemoglobin (HbF) production in erythroid cells. The K562 erythroleukaemia cell line is widely used as a model system in which to study the mechanism of γ‐globin induction by HU. However, the transcription factors required for the upregulation of γ‐globin expression by HU in K562 cells have not been identified. Similarities between the HU and sodium butyrate (SB) pathways suggest cAMP response element‐binding protein (CREB) 1 as a potential candidate. Thus, the aim of the present study was to investigate the possible role of CREB1 in the HU pathway. Experiments were performed using transient and stable RNA interference (RNAi) to show that CREB1 is necessary for HU‐mediated induction of γ‐globin expression and haemoglobin production in K562 cells. Furthermore, western blot analyses demonstrated that CREB1 becomes phosphorylated in a dose‐dependent manner after HU (100–400 µmol/L) treatment of K562 cells for 72 h. We also investigated role of a Gγ promoter CREB1 response element (G‐CRE) in this pathway. Quantitative amplification refractory mutation system–polymerase chain reaction experiments were performed to demonstrate that HU induces the expression of both Gγ and Aγ in this cell line. In addition, electrophoretic mobility shift assays were used to show that levels of CREB1 complexes binding to the G‐CRE site are increased following HU treatment and are decreased in CREB1‐knockdown cells. The results suggest that CREB1 is necessary for γ‐globin induction by HU in K562 cells, a role that may be mediated, in part, through the G‐CRE element.

Background and Objective: As the second cause of cancer-related death, gastric cancer (GC) is a major health challenge worldwide. Today, numerous efforts are underway to discover cancer biomarkers and drugs that affect these biomarkers. One of these biomarkers is the β-catenin protein, the expression of which has recently been shown to increase in GC. In addition, many ongoing efforts have focused on finding organic and natural medicines without the side effects of chemotherapy. One of these natural substances is honeybee propolis. In the present study, the effect of this extract was investigated on β-catenin gene expression in AGS cells.Materials and Methods: Propolis extract was applied to AGS cells at doses of 800, 1200, and 2000 μg/ml at intervals of 48 and 72 h. Next, the expression of this gene was evaluated by extracting RNA using the GAPDH as the reference gene. Finally, the difference in the β-catenin expression between the treatment and control groups was examined by data analysis.Results: A significant decrease was observed in the expression of the β-catenin gene in cells treated within 48 h, but no significant difference in the expression was found in the treatment at 72 h. However, the results are promising for the future use of honeybee propolis in cancer treatment in further studies.