Ferroptosis And Related Drugs In Glioblastoma

Glioblastoma,as the most malignant glioma and one of the most difficult problems in neurosurgery,has been a hot topic in the relevant field.Current treatment methods are maximal surgical resection combined with radiotherapy and chemotherapy.However,the methods still have shortcomings such as incomplete resection,large dose of radiotherapy and tolerance of chemotherapy.Therefore,to clarify the pathogenesis and pathophysiological process of glioblastoma,to search for new treatment methods and to improve the prognosis of patients have become an urgent and important issue,which are also the research focus of neurosurgeons and relevant scholars.Ferroptosis,as a newly discovered mechanism of cell death in recent years,is distinguished from other ways by its characteristics of iron dependence and lipid peroxides accumulation.At present,the relationship between glioblastoma and ferroptosis has not been widely studied.It is still unknown whether the grade and development of glioma can be predicted or judged,and the treatment of tumor can be guided by the relevant indicators of ferroptosis.It has been demonstrated from previous studies about the killing effect of artemisinin on glioblastoma cells.Artemisinin is characterized by low toxicity,selective killing and low drug resistance to normal cells,which makes it one of the popular anti-tumor research directions.It is shown that artemisinin and its derivatives can activate ferroptosis.However,there is little research on artemisinin and glioblastoma,and whether artemisinin can activate ferroptosis in glioblastoma has not been investigated.It is examined in this paper that:(1)By measuring the expression of ferroptosis-related genes in tumor and normal tissues,the study found,in glioblastoma,GPX4 expression increased dramatically,while ACSL4 rise was lower than in low-grade glioma(no significant difference).It was proved that there was low level of ferroptosis activation in glioblastoma,but it did not cause obvious killing effect.The level of ATF4 was up-regulated and it was believed to be involved in tumor resistance to ferroptosis.P53 is also upregulated,but the evidence supporting the correlation between P53 and GPX4 is weak.(2)Through the cell proliferation assay,it was determined that dihydroartemisinin(DHA)had a significantly stronger killing effect on glioblastoma cell lines U87 and A172 than on normal human astrocyte.To explain the selective killing effect of DHA,the expression of transferrin receptor(Tf R)in NHA,U87 and A172 was measured by western blot assay and significant differences were found.The expression of Tf R in U87 and A172 was significantly higher than that in NHA,which may be one of the explanations for the selective killing effect of DHA considering that DHA is closely related to ferrous ions.(3)Through the determination of total peroxides and lipid peroxides in U87 and A172 cell lines treated by DHA,this study found that DHA caused the increase of peroxides,especially lipid peroxides,which meant the activation of ferroptosis.By measuring the expression of ferroptosisrelated proteins,a significant decrease in GPX4 was found,suggesting that GPX4 is a key target for DHA to cause ferroptosis with non-reactive oxygen dependent pathways in glioblastoma cells.The results of immunofluorescence and transmission electron microscopy also confirmed the above conclusions.The use of ferrostatin-1,a ferroptosis inhibitor,significantly reversed the lipid peroxides accumulation and killing effect caused by DHA,suggesting that ferroptosis is one of the key mechanisms responsible for the glioblastoma cell death caused by DHA.Based on the experimental results above,this study draws the following conclusions:(1)The activation level of ferroptosis in glioblastoma is low,which is not enough to produce a killing effect,and the relevant indicators have obvious changes compared with normal tissues,which can be used as the research direction of targeted therapy.(2)Dihydroartemisinin has a selective killing effect,and one of the reasons is that transferrin receptor expression levels of glioblastoma compared to normal tissue increased.(3)Dihydroartemisinin can activate ferroptosis by causing reactive oxygen accumulation and inhibiting GPX4 in glioblastoma,and then produce obvious cytotoxic effects.