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AIM: To scrutinize the role of the Wnt/β-catenin signaling pathway in the epithelial-mesenchymal transition(EMT)of lens epithelial cells under hypoxic conditions, and to further analyze the effect of Dickkopf-1(DKK-1)expression on EMT of lens epithelial cells.METHODS: Human lens epithelial cells(HLEB3 cells)were propagated in vitro and then separated into two groups: one exposed to standard oxygen levels, added DMEM culture solution containing 10% FBS(normoxic group)and another subjected to low oxygen levels(hypoxic group). The hypoxic condition was emulated by applying a concentration of 100 μmol/L cobalt chloride(CoCl2)for 6, 12, 24, and 48h. The utilization of immunofluorescence staining enabled the detection of Wnt3a and DKK-1 expressions, along with the expression and localization of β-catenin protein in these groups. The expression of DKK-1 mRNA was discerned by quantitative real-time polymerase chain reaction(qRT-PCR).RESULTS: Immunofluorescence assays indicated an escalating trend in the Wnt3a and DKK-1 protein expression, which corresponded with the increasing duration of hypoxia. Likewise, an intensified nuclear accumulation of β-catenin protein was observed to be directly proportional to the length of hypoxia treatment. The qRT-PCR demonstrated that the difference in DKK-1 mRNA expression between the normoxic group and the group exposed to hypoxia for 6h was not statistically significant(P>0.05), whereas the DKK-1 mRNA expression of the 12, 24, and 48h hypoxia groups were significantly increased(P<0.001).CONCLUSION: Hypoxia can activate Wnt/β-catenin pathway in lens epithelial cells and induce the expression of DKK-1, thus regulating the Wnt/β-catenin pathway and affecting the EMT process.
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@#[Abstract] Objective: To explore the expression and regulation mechanism of Dickkopf-1 (DKK1) in head and neck squamous cell carcinoma (HNSCC) tissues. Methods: Based on the TCGA database, the relationship of DKK1 expression in HNSCC tissues and its methylation site with patients’prognosis was analyzed. GO and KEGG gene enrichment method were used to analyze the signaling pathways of DKK1 enrichment. STRING was used to analyze the interaction between DKK1 protein and other proteins. TargetScan was used to analyze the miRNAs that regulate the expression of DKK1, and the transcription factors of DKK1 were analyzed with the TRRUST website. Results: DKK1 gene was highly expressed in HNSCC tissues (P<0.01), and its expression level was significantly correlated with the HPV status, age, pathological grade, and clinical stage of patients (all P<0.05); the prognosis of HNSCC patients with high DKK1 expression was poorer than those with low DKK1 expression (P<0.01). There were 19 methylation sites in DKK1, 12 of which were significantly different between cancer tissues and normal tissues (P<0.05), and 11 sites were significantly related to the prognosis of HNSCC (P<0.05). In addition, miRNA, circRNA, lincRNA and transcription factors, etc. also participated in the regulation of DKK1. A total of 5 DKK1-related PPI networks that may involve in the occurrence, development, invasion and metastasis of HNSCC were obtained. Conclusion: DKK1 is highly expressed in HNSCC tissues and is a risk factor for poor prognosis of HNSCC patients. DKK1 plays an important role in the pathogenesis of HNSCC and is expected to become a potential target for HNSCC treatment.
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@# Objective： ：To study the effect of silencing DKK1 (Dickkopf1) gene on the proliferation, cell cycle and apoptosis of gastric cancer AGS cells and the action mechanism. Methods： ：The DKK1-shRNA vector was constructed and transfected into AGS cells. The stably transfected cell lines were screened. The total protein and RNAof the transfected cells were extracted and the mRNAand protein expressions of DKK1 were detected by qPCR and WB, respectively. The experiment was divided into blank control group (Control), negative control group (shNC) and DKK1 silence group (DKK1-shRNA). CCK8 assay was used to detect the proliferation ofAGS cells of each group cultured for 0, 24, 48, 72, 96, 120 and 144 h, and flow cytometry was used to analyze the cell cycle and apoptosis in each group. The relationship between DKK1 and clinicopathological features of gastric cancer was analyzed after searching HPA database. Results：The gastric cancer AGS cells with stable DKK1 gene knockdown was successfully established, and it was confirmed that the mRNA and proteinexpressions of DKK1 in DKK1-shRNA group decreased by 72% and 47%, respectively, compared to shNC group (all P<0.05). The cell proliferation curve showed that, the cell proliferation in DKKl-shRNAgroup significantly decreased after 72 hour of culture compared with that in control and shNC groups (P<0.05). The cell number of S phase decreased from 32.06% to 25.87%, while the number of G2/M phase increased from 8.49% to 21.26% compared with shNC group (all P<0.05). The number of apoptotic cells also statistically increased from 10.34% to 20.65% (all P<0.05). The data of HPAdatabase showed that DKK1 mRNAlevel in gastric cancer tissues was significantly higher than that in normal tissues, and the high expression of DKK1 mRNAwas negatively correlat ed with the survival rate of gastric cancer patients. Conclusion: : Silencing DKK1 gene can inhibit the proliferation of gastric cancer cells, arrest cells in G2/M phase and promote cell apoptosis. DKK1 plays a pro-carcinogenic effect in gastric cancer.