Objective To investigate the molecular mechanism by which super enhancers(SEs)regulate the expression of the genetic suppressor element 1(GSE1)and influence the proliferation of breast cancer cell line MCF-7.Methods The oncogene GSE1,driven by SEs,was identified through analysis of the ChIP-seq dataset of MCF-7 cells obtained from the GEO database.The protein expression level of GSE1 was assessed via Western blot following treatment with the bromodomain-containing protein 4(BRD4)inhibitor JQ1.The expression of GSE1 across various cancers and different breast cancer subtypes was analyzed using the Human Protein Atlas(HPA)and The Cancer Genome Atlas(TCGA)databases,respectively.Overall survival(OS)of breast cancer patients was compared between the GSE1 high-expression and low-expression groups using the GEPIA database.Immunohis-tochemistry(IHC)was performed to evaluate GSE1 expression in breast cancer tissue samples.The mRNA expres-sion levels of GSE1 in different breast cancer cell lines were validated by RT-qPCR.A GSE1 interference vector was constructed and transfected into MCF-7 cells,and the knockdown efficiency was assessed using Western blot.Cell proliferation and migration were evaluated using CCK-8 assay,colony formation assay,wound healing assay,and Transwell migration assay.Potential GSE1-interacting proteins were predicted using the STRING database.Finally,Western blot analysis was conducted to assess changes in epithelial-mesenchymal transition(EMT)-related proteins and key components of the Wnt/β-catenin signaling pathway.Results The integrative genomics viewer(IGV)was used to visualize ChIP-seq data from MCF-7 cells,and the rank ordering of super enhancers(ROSE)algorithm was applied to predict the SE region of GSE1 in the MCF-7 genome.GSE1 and BRD4 expression levels were significantly reduced following JQ1 treatment(P<0.05).High expression levels of GSE1 in breast cancer were confirmed through analyses using the HPA,TCGA,and GEPIA databases,as well as IHC,and these find-ings were associated with poor prognostic outcomes in breast cancer patients(P<0.05).RT-qPCR results further demonstrated that GSE1 is significantly upregulated in breast cancer cells(P<0.05).Analysis of the STRING database revealed a strong correlation between GSE1 and Snail(Snai1).Transfection of a GSE1-specific interference vector significantly inhibited the proliferation and migration of MCF-7 cells compared to the control group,upregu-lated E-cadherin and Occludin expression,and downregulated N-cadherin and Snail expression(P<0.05).Addi-tionally,knockdown of GSE1 resulted in decreased expression of Wnt/β-catenin signaling pathway-related proteins,including β-catenin,Wnt-5a,and Cyclin-D1,along with increased Axin1 expression(P<0.05).Conclusion SE driven GSE1 promotes the proliferation,migration and EMT of MCF-7 cells via the Wnt/β-catenin signaling pathway.

BACKGROUND:THZ1,an inhibitor of cyclin-dependent kinase 7,has been shown to inhibit the proliferation of a variety of tumor cells,but whether THZ1 can affect the stemness of glioma stem cells through the Wnt/β-catenin signaling pathway remains unclear.OBJECTIVE:To investigate the effect of THZ1 on stemness of glioma cell U87 and its mechanism.METHODS:U87 adherent cells were cultured to form stem cell mammospheres.The expressions of stemness related proteins were verified by western blot assay.The effect of THZ1 on half maximal inhibitory concentration(IC50)of U87 cells was determined by Cell Counting Kit-8(CCK-8)assays.The effects of THZ1 on proliferation and migration of U87 cells were determined by cell colony-formation assays,cell wound healing assays,and Transwell migration assays.The effect of THZ1 treatment on mammosphere forming rate and mammosphere size of U87 stem cells was analyzed.Stemness associated proteins CD133,ABCG2,Nanog,OCT4,SOX2,epithelial-mesenchymal transformation-related proteins E-cadherin,N-cadherin,Occludin,Snail,and Wnt/β-catenin pathway associated proteins Axin1,β-Catenin,WNT-5A,GSK3β,Cyclind-1,and C-myc were measured by western blot assay.RESULTS AND CONCLUSION:(1)Compared with adherent cells,the expressions of stemness related proteins Nestin,CD133,ABCG2,Nanog,OCT4,and SOX2 were significantly increased.(2)Compared with the control group,THZ1 decreased the proliferation and migration of U87 cells.(3)THZ1 inhibited the mammosphere forming rate and mammosphere size of U87 stem cells.(4)After THZ1 treatment,the expression of N-cadherin and Snail decreased,while the protein expression of E-cadherin and Occludin increased.(5)THZ1 treatment decreased the expression of Wnt/β-catenin pathway related proteins Axin1,β-Catenin,Wnt-5A,GSK3β,Cyclind-1,and C-myc in U87 stem cells.It is concluded that THZ1 can suppress the proliferation and migration of U87 cells,and inhibit the mammosphere forming ability,stemness related protein expression,and epithelial-mesenchymal transformation ability of U87 stem cells by down-regulating the expression of Wnt/β-catenin signaling pathway related molecules.

BACKGROUND:THZ1,an inhibitor of cyclin-dependent kinase 7,has been shown to inhibit the proliferation of a variety of tumor cells,but whether THZ1 can affect the stemness of glioma stem cells through the Wnt/β-catenin signaling pathway remains unclear.OBJECTIVE:To investigate the effect of THZ1 on stemness of glioma cell U87 and its mechanism.METHODS:U87 adherent cells were cultured to form stem cell mammospheres.The expressions of stemness related proteins were verified by western blot assay.The effect of THZ1 on half maximal inhibitory concentration(IC50)of U87 cells was determined by Cell Counting Kit-8(CCK-8)assays.The effects of THZ1 on proliferation and migration of U87 cells were determined by cell colony-formation assays,cell wound healing assays,and Transwell migration assays.The effect of THZ1 treatment on mammosphere forming rate and mammosphere size of U87 stem cells was analyzed.Stemness associated proteins CD133,ABCG2,Nanog,OCT4,SOX2,epithelial-mesenchymal transformation-related proteins E-cadherin,N-cadherin,Occludin,Snail,and Wnt/β-catenin pathway associated proteins Axin1,β-Catenin,WNT-5A,GSK3β,Cyclind-1,and C-myc were measured by western blot assay.RESULTS AND CONCLUSION:(1)Compared with adherent cells,the expressions of stemness related proteins Nestin,CD133,ABCG2,Nanog,OCT4,and SOX2 were significantly increased.(2)Compared with the control group,THZ1 decreased the proliferation and migration of U87 cells.(3)THZ1 inhibited the mammosphere forming rate and mammosphere size of U87 stem cells.(4)After THZ1 treatment,the expression of N-cadherin and Snail decreased,while the protein expression of E-cadherin and Occludin increased.(5)THZ1 treatment decreased the expression of Wnt/β-catenin pathway related proteins Axin1,β-Catenin,Wnt-5A,GSK3β,Cyclind-1,and C-myc in U87 stem cells.It is concluded that THZ1 can suppress the proliferation and migration of U87 cells,and inhibit the mammosphere forming ability,stemness related protein expression,and epithelial-mesenchymal transformation ability of U87 stem cells by down-regulating the expression of Wnt/β-catenin signaling pathway related molecules.

Objective To investigate the molecular mechanism by which super enhancers(SEs)regulate the expression of the genetic suppressor element 1(GSE1)and influence the proliferation of breast cancer cell line MCF-7.Methods The oncogene GSE1,driven by SEs,was identified through analysis of the ChIP-seq dataset of MCF-7 cells obtained from the GEO database.The protein expression level of GSE1 was assessed via Western blot following treatment with the bromodomain-containing protein 4(BRD4)inhibitor JQ1.The expression of GSE1 across various cancers and different breast cancer subtypes was analyzed using the Human Protein Atlas(HPA)and The Cancer Genome Atlas(TCGA)databases,respectively.Overall survival(OS)of breast cancer patients was compared between the GSE1 high-expression and low-expression groups using the GEPIA database.Immunohis-tochemistry(IHC)was performed to evaluate GSE1 expression in breast cancer tissue samples.The mRNA expres-sion levels of GSE1 in different breast cancer cell lines were validated by RT-qPCR.A GSE1 interference vector was constructed and transfected into MCF-7 cells,and the knockdown efficiency was assessed using Western blot.Cell proliferation and migration were evaluated using CCK-8 assay,colony formation assay,wound healing assay,and Transwell migration assay.Potential GSE1-interacting proteins were predicted using the STRING database.Finally,Western blot analysis was conducted to assess changes in epithelial-mesenchymal transition(EMT)-related proteins and key components of the Wnt/β-catenin signaling pathway.Results The integrative genomics viewer(IGV)was used to visualize ChIP-seq data from MCF-7 cells,and the rank ordering of super enhancers(ROSE)algorithm was applied to predict the SE region of GSE1 in the MCF-7 genome.GSE1 and BRD4 expression levels were significantly reduced following JQ1 treatment(P<0.05).High expression levels of GSE1 in breast cancer were confirmed through analyses using the HPA,TCGA,and GEPIA databases,as well as IHC,and these find-ings were associated with poor prognostic outcomes in breast cancer patients(P<0.05).RT-qPCR results further demonstrated that GSE1 is significantly upregulated in breast cancer cells(P<0.05).Analysis of the STRING database revealed a strong correlation between GSE1 and Snail(Snai1).Transfection of a GSE1-specific interference vector significantly inhibited the proliferation and migration of MCF-7 cells compared to the control group,upregu-lated E-cadherin and Occludin expression,and downregulated N-cadherin and Snail expression(P<0.05).Addi-tionally,knockdown of GSE1 resulted in decreased expression of Wnt/β-catenin signaling pathway-related proteins,including β-catenin,Wnt-5a,and Cyclin-D1,along with increased Axin1 expression(P<0.05).Conclusion SE driven GSE1 promotes the proliferation,migration and EMT of MCF-7 cells via the Wnt/β-catenin signaling pathway.