Effect Of Mitochondrial Calcium Uniporter On Proliferation And Self-renewal Of Glioma Stem Cells

Glioma is a highly malignant primary tumor in the central nervous system,and the current treatment can only play a palliative role.It has the characteristics of therapeutic resistance,easy to relapse,high mortality,and the median survival of patients is only 12 to 15 months.Glioma stem cells(GSC)are a class of glioma cells with self-renewal,multidirectional differentiation and tumorigenesis.More and more evidences show that GSC promotes tumor resistance to chemoradiotherapy,and eventually leads to cancer recurrence.How to regulate glioma stem cells will be the key to high-level glioma therapy.Tumor cells require superior adaptations to survive,metastasize,and resist treatment,and for this they rely on a variety of molecular processes,including the biological activity of mitochondria.Mitochondria are not only the source of energy,but also the hub of signal transduction and control of cell fate.It can quickly absorb intracellular calcium ions and promote the activity of intracellular calcium signal.The mitochondrial calcium uniporter(MCU)and its related regulatory factors are responsible for transporting calcium to the mitochondrial matrix.Due to its central role in mitochondrial calcium ion transport and its ability to influence the fate of cell behavior,MCU is being studied in different tumor models.However,there are still few studies on the influence of MCU on tumor genesis and development,and whether MCU affects the function of glioma stem cells has not been reported.This project will explore the regulation of MCU on glioma stem cells,clarify the influence of MCU on the proliferation and self-renewal ability of brain glioma stem cells,and verify whether MCU affects the tumorigenesis ability of glioma stem cells,so as to provide some basis for MCU to become a potential therapeutic target of brain glioma.It was found that MCU could regulate the energy generation during cell mitosis,while some articles reported that GSC specifically relied on aerobic respiration to provide energy.Therefore,our scientific question is to explore whether MCU plays an important role in GSC.In this study,we found that in mice and human glioma tissue samples,MCU was highly expressed in glioma stem cells,and knocking down MCU in GSC could inhibit the self-renewal ability and proliferation of GSC,and affect the tumorigenesis ability of GSC.At the cellular level,we found that MCU was highly expressed in glioma stem cells,and we expressed mitochondrial calcium fluorescent probe 4mt-GCaMP6 in T387 and 387NSTC.The changes of mitochondrial calcium levels in T387 and 387NSTC were monitored by living cell dynamic observation system,and it was found that the maximum mitochondrial calcium absorption capacity of T387 was stronger than387NSTC.We infected GSC with a virus containing the MCU knockdown sequence.After further screening,the interference effect of MCU was detected,and we found that the cell viability of GSC decreased significantly.The size and number of tumor spheres were also significantly inhibited,and promote the apoptosis of GSC.GSC,normal glial cells(NHA),and neural progenitor cells(16157)were treated with DS16570511,an inhibitor of MCU,we found that low concentration of the inhibitor inhibited the cell viability and tumor ball size of GSC and 16157,and showed a small inhibitory effect on normal cells,indicating that low concentration of DS16570511 had a specific inhibitory effect on stem cells,while normal brain cells were less sensitive to DS16570511.These experiments preliminarily suggest that MCU can inhibit the function of glioma stem cells,and MCU as a therapeutic target for glioma may have minor side effects.We construct a mouse model of in situ glioma,found that the tumor size of the tumor-bearing mice was significantly inhibited and the survival time of the mice was significantly prolonged after knocking down the MCU,compared with the tumor-bearing mice in the control group.In summary,we found that MCU was highly expressed in glioma stem cells,and the maximum mitochondrial calcium absorption capacity of GSC was stronger than that of NSTC,indicating that MCU had a stronger function in GSC.We also found that MCU regulates the self-renewal and proliferation of GSC,and affects the tumorigenesis ability of GSC.MCU inhibitor DS16570511 has a specific killing effect on GSC,but has little cytotoxicity on normal brain tissues.Inoculating GSC with MCU knockdown into mouse brain can significantly inhibit the size of tumor formation,delay the development of tumor,and significantly prolong the survival time of tumor-bearing mice.The above experimental results prove that MCU can be used as a specific regulatory target of glioma stem cells,which may provide a new strategy for the treatment of glioma.