| Glioma is a type of the invasive primary tumor and clinical treatmentincluding tsurgical therapy, radiotherapy and chemotherapy doesn’t get a bettereffect on it. Compared with other kinds of tumor, targeted treatment didn’timprove long-term survival of glioma.The proteasome as antitumor target research and its clinical applicationgets great attention. Ubiquitin-proteasome system is one of the importantprotein degradation pathways. The combination of ubiquitin molecules and thesubstrate protein lysine side chain was mediated by the ubiquitin ligase and thenthe ubiquitin polymerization helps to locate it to the proteasome for degradation.This process can keep the level of intracellular proteins and its functionsrelatively stable. Once the proteasome is inhibited, can it significantly reducethe activiey of proteins related to cell growth and cell apoptosis,also it canaggregate intracellular protein and cause multiple cascade reaction, eventuallyto lead to tumor cell apoptosis. Therefore, proteasome inhibitor has been a newchoice for antitumor.The Bcl-2protein family plays an important role for the tumor cellapoptosis. Recent studies show that Mcl-1, members of Bcl-2family, has a closecontact with resistance of tumor cells. Except for inducing tumor cell apoptosis,proteasome inhibitors may increase anti-tumor protein expression levels,thereby to weaken its anti-tumor effect. Thus, when giving antitumor drugs, theexpression of antiapoptotic proteins will increase, that may improve thesensitivity of tumor cells to anti-tumour drugs.Proteasome inhibitors such as Bortezomib (BTZ) has been used for clinic, many studies show that BTZ has a good curative effect on multiple myeloma,leukemia, lymphoma cells. This research chooses glioma as the object; firstly toexplore the influence of BTZ to glioma cell survival and apoptosis, and thenaccording to related articles to introduce antiapoptotic proteins Mcl–1to cellapoptosis induced by BTZ, finally to discuss the effect for it.Methods1. To detect the cell survival rate for U251and U87after BTZ by MTT.2. To detect cell apoptosis for U251and U87after BTZ by Flow cytometry.3. To detect the effect for the expressions of the apoptotic related proteinsCleaved Caspase-3, PARP and Cytochrome C in U251and U87after BTZ byWestern Blot, including the expressions of Mcl-1.4. To detect the cell survival rate with BTZ after Mcl-1siRNA by MTT.5. After Mcl-1siRNA inhibit Mcl-1, Flow cytometry detected the effect ofBTZ on U251and U87cell apoptosis6. The expressions of the apoptotic related proteins Cleaved Caspase-3,PARP and Cytochrome C was detected by Western Blot in the Mcl-1siRNAU251and U87cell treated with BTZ.Result1. BTZ can decrease the viability of U251and U87cells in dose-dependenttrends.2. Through flow cytometry, BTZ can significantly increase the apoptosisrate in U251and U87cells.3. The expressions of apoptotic related proteins Cleaved Caspase-3, PARPand Cytochrome C remarkably is increased in U251and U87cells, which aretreated by BTZ. Meanwhile, it leads to the expression of Mcl-1increase.4. Compared with the BTZ, the cell viability of U251and U87cells significantly is decreased in the group of siRNA Mcl-1, which inhibit theexpression of Mcl-1.5. Compared to the group of Control siRNA, the group of siRNA Mcl-1can further enhance the apoptosis induced by BTZ.6. Compared to the group of siRNA group, the expression of Mcl-1wasinhibited and it could further increase the expressions of apoptotic relatedproteins Cleaved Caspase-3, PARP and Cytochrome C induced by BTZ.Conclusion1. The U251and U87glioma cells were chosen as the object and researchresults show that BTZ can induce U251and U87glioma cells apoptosis, also itupregulates the expression of anti-apoptosis protein Mcl-1.2. When using siRNA Mcl-1to inhibit the expression of Mcl-1, we foundthat it could increase the cell apoptosis in the U251and U87glioma cellsinduced by BTZ. By the same time, we found that the suppression of Mcl-1canenhance the sensitivity of U251and U87glioma cells for BTZ. |
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