The Effect And Possible Mechanism Of Silencing ABCE1 Gene On Proliferation In Human Glioma Cells

Glioma is the most common primary brain tumor,accounting for about 40% of all intracranial nervous system tumors and 80% of all malignant tumors.Gliomas have the characteristics of rapid growth,malignant infiltration,high recurrence rate,high mortality,and low cure rate,the patient's survival period of malignant glioma is only one year.The current treatment of gliomas has great limitations.Therefore,the hot spot of researches of gliomas is exploring the key molecular targets of glioma treatments and seeking effective drugs and methods.In the study of cancer,the expression of ATP-binding cassette E1(ABCE1)is higher in a wide variety of tumor.ABCE1 codes a protein,which contains 599 amino acid residues and the molecular weight of ABCE1 is about 68 KD.ABCE1 gene is a member of the ABC multigene family,and it mainly exists in the cytoplasm and mitochondria,widely distributed in the archaea and eukaryotes.It encodes a protein originally identified for its inhibition of ribonuclease.Other studies have shown that ABCE1 plays an important role in the assembly of viral capsid,protein synthesis and ribosome recirculation.The studies in tumor cells showed that the overexpression of ABCE1 in cells could enhance the ability of cell clone formation.ABCE1 could interact with a variety of factors which play an important role in tumor proliferation.So,ABCE1 is a crucial gene for tumor proliferation,but the role of ABCE1 in glioma cells has not been reported.This study focused on the mechanism of ABCE1 in the proliferation,migration and apoptosis of glioma cells and obtained the following main results.In this study,we tested the expression of mRNA and protein of ABCE1 by qRT-PCR and Western blot in three kinds of glioma cell lines and one normal glial cell line,respectively.The results showed that mRNA and protein of ABCE1 are expressed in different glioma and normal glial cells,but the expression in glioma cells was higher than that in normal glial cells.According to characteristics of transfectionefficiency of these three glioma cell,we chose U251 glioma cell as the research object.We designed and synthesized interference fragment specific for ABCE1 mRNA(ABCE1-siRNA),and transfected the experimental group(ABCE1-siRNA)and the negative control group(ABCE1-NC)into U251 glioma cells by liposome transfer,respectively.The results of qRT-PCR and Western blot confirmed that the expression of mRNA and protein in glioma cells were significantly inhibited.Cell growth situation tested by MTT indicated that the ability of cell proliferation in experimental group was significantly inhibited.Cell cycle and apoptosis by flow cytometry confirmed that the amount of cells in S phase was significantly increased in experimental group compared with control group,which indicated that the cell cycle is blocked in S phase.Apoptosis in experimental group is significantly higher than the other controls.The cell scratch assays showed that the ability of cell migration of glioma was significantly inhibited.Temozolomide(TMZ)has become the first choice for treatment of glioma,and have certain characterized as its effect and safety.The treatment mechanism of TMZ is to make the transalkylation O6-methylguanine DNA alkyltransferase inactivated,causing DNA damage,eventually leading to cell apoptosis.Despite the clinical studies have confirmed that TMZ could improve the prognosis of patients with malignant glioma,but the survival time of patients is only 17-19 months.And with lengthening duration of treatment,drug curative effect has been reduced.Therefore,improving the sensitivity of tumor cells to drugs is also a hot topic.In order to increase the sensitivity of glioma cells to TMZ,we first combined low concentration of TMZ with ABCE1-siRNA in this study.The results showed that the ability of cell proliferation in combination group(ABCE1-siRNA + TMZ)was significantly inhibited compared with the single action group(ABCE1-siRNA and TMZ),the amount of cells in S phase was significantly increased,and apoptosis is also significantlyhigher than the control group.These results suggested that silence ABCE1 could improve the sensitivity of glioma cells for TMZ,and could more effectively induced glioma cell cycle arrest and apoptosis.In conclusion,the expression of ABCE1 in glioma cells was higher than that in normal glial,and silencing of ABCE1 the proliferation and migration of cell was inhibited,and cell apoptosis was promoted,and cell cycle was blocked in S phase.On the other hand,silencing of ABCE1 the sensitivity of glioma cells to TMZ was enhanced.These results suggest that ABCE1 is closely related to the proliferation and migration of glioma.So,ABCE1 is expected as an effective therapeutic target to provide the experimental data for further exploring the new way and method for the treatment of gliomas.