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AIM:To investigate the effect of suppression of mel18 gene on the differentiation of human acute myeloid leukemia cell line HL 60 induced by cinnamaldehyde ( CA) .METHODS:HL60 cells were treated with low con-centration of CA or all-trans retinoic acid (ATRA).shRNAmel18 vector and shRNALuc control vector were employed to package lentiviruses which were then used to infect HL 60 cells.The virus-infected HL60 cells were treated with low con-centration of CA , and ATRA was used as a positive control of differentiation-inducing agent .The differentiation markers on the cell surface and cell cycle of virus-infected HL60 cells were analyzed by flow cytometry .Western blot was used to deter-mine the expression of MEL18, cyclin D1 and p27, as well as the phosphorylation level of Akt .RESULTS:Low concen-tration of CA and ATRA increased the expression of granulocytic differentiation marker CD 11b on the HL60 cells, with the decreased expression of MEL 18 in the HL60 cells.The expression of MEL18 decreased in shmel18 virus-infected HL60 cells (shmel18-HL60 cells), but did not change in shLuc-HL60 cells.The expression of CD11b on shmel18-HL60 cells increased with G 1-phase arrest , which went even higher after treatment with CA .The phosphorylation level of Akt and the expression of cyclin D1 decreased in shmel18-HL60 cells with the increase in the expression of p27.CONCLUSION:In-hibition of mel18 gene leads HL60 cell granulocytic differentiation .mel18 gene may affect the differentiation of HL 60 cells by regulating cyclin D1 and p27 via PI3K/Akt signaling pathway.PI3K/Akt signaling pathway is also involved in CA-in-duced differentiation of HL60 cells by suppressing mel18 gene expression.
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AIM:To investigate the effect of suppression of mel18 gene on the differentiation of human acute myeloid leukemia cell line HL 60 induced by cinnamaldehyde ( CA) .METHODS:HL60 cells were treated with low con-centration of CA or all-trans retinoic acid (ATRA).shRNAmel18 vector and shRNALuc control vector were employed to package lentiviruses which were then used to infect HL 60 cells.The virus-infected HL60 cells were treated with low con-centration of CA , and ATRA was used as a positive control of differentiation-inducing agent .The differentiation markers on the cell surface and cell cycle of virus-infected HL60 cells were analyzed by flow cytometry .Western blot was used to deter-mine the expression of MEL18, cyclin D1 and p27, as well as the phosphorylation level of Akt .RESULTS:Low concen-tration of CA and ATRA increased the expression of granulocytic differentiation marker CD 11b on the HL60 cells, with the decreased expression of MEL 18 in the HL60 cells.The expression of MEL18 decreased in shmel18 virus-infected HL60 cells (shmel18-HL60 cells), but did not change in shLuc-HL60 cells.The expression of CD11b on shmel18-HL60 cells increased with G 1-phase arrest , which went even higher after treatment with CA .The phosphorylation level of Akt and the expression of cyclin D1 decreased in shmel18-HL60 cells with the increase in the expression of p27.CONCLUSION:In-hibition of mel18 gene leads HL60 cell granulocytic differentiation .mel18 gene may affect the differentiation of HL 60 cells by regulating cyclin D1 and p27 via PI3K/Akt signaling pathway.PI3K/Akt signaling pathway is also involved in CA-in-duced differentiation of HL60 cells by suppressing mel18 gene expression.
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Mel-18 gene is one of the core members of the PcG (polycomb group) family,which plays an important role in embryogenesis,cell growth and proliferation and self-renewal of stem cells.Mel-18 gene expressing abnormally has been related to human tumorigenesis,development process.Mel-18 serves as a tumor suppressor gene and inhibits tumor growth through transcriptional repression of Bmi-1 and c-myc.Mel-18 expression is decreased at transcriptional and translational levels in most human cancers including breast cancer,prostate cancer,and gastric cancer and other tumors.Mel-18 is expected to become a prognostic marker for human cancers.
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Background and purpose: Mel-18 is one of the mammalian polycomb group members. A number of related researches have implied that Mel-18 may play a role in human tumorigenesis.In this study, we measured the expression of Mel-18 in gastric carcinoma cells in vivo to explore the expression and clinical significance of Mel-18 in gastric carcinoma. Methods: Real time RT-PCR was used to detect the expression of Mel-18 in cancer tissue and corresponding normal tissue in 52 cases of gastric carcinoma. The association between Mel-18 expression and the clinicopathological parameters of the tumors was analyzed. Results: The analysis revealed that there was significantly decreased expression of Mel-18 in 18 (34.62%)carcinoma tissues in comparison with para-cancer normal tissue. There was no correlation between Mel-18 expression and clinicopathological parameters, such as age, gender, tumor size and histological differentiation (P>0.05).The decrease of Mel-18 expression was significantly negatively correlated with lymph node metastasis and clinical stage (P<0.05). The expression levels of Mel-18 evaluated by the ratios of gene expression were 1.357,0.453,0.183 and 0.170 in stage Ⅰ, Ⅱ,Ⅲ and Ⅳ gastric carcinoma, respectively. They were 0.634 and 0.210 in patients without lymph node metastasis and in patients with lymph node metastasis, respectively. Expression of Mel-18,lymph node metastasis, and clinical stage were significant covariates, respectively (P<0.05). Conclusion: Our results showed that Mel-18 might play a crucial role in tumorigenesis and progression of gastric carcinoma. It is possible that Mel-18 could be used as one of the biomarkers for predicting the prognosis of gastric carcinoma.
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0.05).The decrease of Mel-18 expression was signifi cantly negatively correlated with lymph node metastasis and clinical stage(P