The Roles And Mechanism Of FOXO1 In Glioblastoma Tumorigenesis

Objective: Glioblastoma(GM)has been become the most aggressive and popular central nervous system malignancy in the world.However,the causes of glioblastoma carcino-genesis and progression are still unknown.The occur of cancer,including Glioblastoma,is a cascade of linked sequential steps involving multiple regulated genes and multiple steps,including the regulation by various of transcription factor.FOXO members consist of a conserved domain which bind DNA sequence TTGTTTAC at target genes.FOXO family plays crucial function in gene transcription,thereby mediate cell process,such as DNA damage repair,apoptotic cell death,glucose metabolism,cell cycle control and car-cinogenesis.In this paper,we focus on the roles and molecular mechanism of FOXO1(FOXO member)in the pathologic process of glioblastoma.Methods: 1.In this paper,we investigated the effectiveness of overexpression or knock down FOXO1 plasmids by q RT-PCR and Western blot.We investigated the effects on cell pro-liferation and cell cycle in glioblastoma cells by MTT assay,colony formation assay and flow cytometry.Subcutaneous tumor in nude mice,Western blot and immunohistochem-istry were used to detect the effects of FOXO1 on proliferation and cell cycle in vivo.2.In this paper,q RT-PCR and Western blot were used to detect the effect of FOXO1 on the process of EMT in glioblastoma cells.Transwell migration assay was used to detect the effect of FOXO1 on the migration in glioblastoma.3.q RT-PCR and Western blot were used to detect the effects of FOXO1 on several pro-tein associated with cell senescence.Ch IP assay was used to detect the interaction be-tween FOXO1 and SIRT1.4.q RT-PCR and Western blot were used to detect the expression of FOXO1 in glioblas-toma cells and clinical tissues.Immunohistochemistry was used to detect the expression of FOXO1 in glioblastoma clinical tissues.The correlation of FOXO1 with differentia-tion,age,gender,pathological grade,tumor size,neck lymph node metastasis and prog-nosis.Results: 1.Overexpression or knock down FOXO1 plasmids were constructed sucessfully.Over-expression of FOXO1 inhibited proliferation and the process of cell cycle in glioblas-toma cells.Knocking down of FOXO1 promoted proliferation and the process of cell cycle in glioblastoma cells.Overexpression of FOXO1 inhibited the subcutaneous tu-morigenic ability and the process of cell cycle in nude mice.2.Overexpression of FOXO1 inhibited EMT process and metastasis in glioblastoma cells.Knocking down of FOXO1 promoted EMT process and metastasis in glioblastoma cells.3.FOXO1 promoted the expression of protein associated with cell senescence,SIRT1 and p16INK4a..FOXO1 and SIRT1 has negative interaction.4.Compared with normal human astrocytes,the expression of FOXO1 was decreased.In clinical tissues,the expression of FOXO1 in human glioblastoma tissues was decreased than adjacent normal tissue.FOXO1 expression negative correlated with pathological grade,tumor size and neck lymph node metastasis.But,differentiation,age and gender has no correlation with FOXO1.Survival curve indicated that patients with high expres-sion of FOXO1 was dramatically longer than that with low expression of FOXO1.Conclusions:1.FOXO1 inhibited cells proliferation by inhibiting the process of cell cycle in gli-oblastoma.2.FOXO1 inhibited EMT and metastasis in glioblastoma cells.3.FOXO1 promotes senescence via transcriptional inhibition SIRT1.4.Compared with the control group,FOXO1 was decreased in glioblastoma cells and tissues.FOXO1 expression negative correlated with pathological grade,tumor size,neck lymph node metastasis and prognosis.