Research Of Culture, Identification, Character Of Different Sites And Radiosensitivity For Brain Tumor Stem Cells

Bankground and ObjectiveIntracranial tumours that originate from neuroepithelial tissue is the mostcommon brain tumours. Although a large amout of basic and clinical research have been made, prognosis of patients is not still satisfying.Brain tumours are typically comprised of morphologically diverse cells that express a variety of neural lineage markers. Study of brain tumours by traditional histopathology has only yielded a limited amount of knowledge of the clinical behavior of the tumour. It is recognized that tumours with vastly different histology have a different prognosis, but often brain tumours that share similar morphology and phenotype can have a very different prognosis and response to treatment. Brain tumours of the same type histologically can also have a very different behaviour in patients of different ages. Although major advances have been made in the understanding of the molecular genetic alterations of some types of brain tumours, particularly medulloblastomas and malignant gliomas, they are not yet applied to clinic simultaneously, the total therapeutic efficacy have a significant difference.Cancer stem cells theory occurring from Leucocythemia and breast cancer suggests that not all the cells in the tumour have the same ability to proliferate and maintain the growth of the tumour. Only a relatively small fraction of cells in the tumour, termed cancer stem cells, possess an ability to extensively proliferate and self renew. Most of tile tumour cells lose the ability to proliferate and self renew and they differentiate into tumour cells that become the phenotypic signature of the tumour. Finding tile key cells in the rumour population that are able to maintain the tumour will give insight into the mechanism of tumorigenesis.Brain rumour stem cells theory suggest that cells similar to NSC existed in brain tumor and maybe participate in formation of brain tumor. They can form brain tumor sphere(BTS) in vitro and have ablities of self-renewal, abnormal proliferation. They can differentiate into neural and galotinous similar to cell proportion of primarily tumor in certain environment. They are a little fraction expressed CD133 in brain tumour and termed brain tumor stem cell(BTSC).Brain of nude mice injected with CD133+ cell may produce tumour similar to primarily tumor; tumor similar to phenotype occur in another nude mice on repeatability operation. These suggest that brain tumor stem cell may be one of important sources that lead to occurrence, generation, recrudescence and infiltration of brain tumor.Design of experiment's is carried out based on above theory and clinical reality apply. To isolate, cultivate and identificate brain tumor stem cells(BTSC) in glioma, to observe the growing pattern of BTSC, to establish foundation for further research of BTSC; to explore individual localizational treatment plan.MethodsGlioma cells from five deferent sites were dissociated immediately, triturated into single cells in sterile DMEM-F12 medium and then filtered. Tumor cells were seeded into serum-free DMEM-F12 medium for proliferation of BTSCs. Expression of CD133 and Nestin can be detected with cell immunofluorescence. In order to determine concrete target for radiotherapy, we examined growth of cells from different sites in glioma with MTT , flow cytometry; We used 2Gy 3Gy 5GY 8GY 12Gy 15Gy irradiation dosage to irradiate Cells of Brain tumor sphere(BTS) from the activest cell site. Manipulating data with SPSS10.0, checking the index about different place or different dose after the radiation of the X line, analyzing statistical significance with analysis of variance(One Way ANOVA), and making multiple comparison with the least significant difference(LSD).ResultsCells which were extracted from glioma can not only survive and grow by means of suspension in serum free medium but proliferate into the clonal sphere. The clonal sphere still maintained strong ability of self-renewal and proliferation after passage. The specific marker CD133 , nestin can be expressed by BTSC in vitro. Distinct activities of proliferation can be found among BTSCs from different sites of glioma. Different irradiation dosage had different influence on BTSC. X line dosages above 8 Gy have notable effect killing brain tumour stem cells.ConclusionBTSC can be found in glioma and can be isolated and cultivated in vitro. BTSCs express nestin and CD133. Glioma had heterogeneity and may have different proliferational activity of BTSCs in different sites. Different X dosage to kill BTSCs should be chosen on radiotherapy.