Comparative Protectics Analyses Of Neural Stem Cell And Brain Tumor Stem Cell

Stem cells are defined as cells that have the ability to perpetuate themselves through self renewal and to generate mature cells of a particular tissue through differentiation. All stem cells must self-renew and regulate the relative balance between self-renewal and differentiation. Recently, several groups have deseribed the existence of a cancer stem cell population in human gliomas, which raises fundamental issues concering their actual ability to drive cancer growth and recurrence. The BTSC hypothesis suggests that not all the cells in gliomas have the same ability to proliferate and maintain the growth of the tumor. Only a relatively small fraction of cells in the tumor possess the ability to proliferate and self-renew extensively. Most of the tumor cells lose the ability to proliferate and self-renew and they differentiate in to tumor cells that become the phenotypic signature of the tumor. The presence of BTSC will have important implications for investigating the tumorigenic process in the central nervous system. However, there are many questions about BTSC remains unclear, many definitive answers may have to wait for. (1) BTSCs are lack of specific surface markers. It is critical to stress the distinction between NSC and BTSC. (2) The pathogenesis of BTSC differentiation is still unknown, which is very important to tumorigenic. In the present study, we have extended the gel-based proteomic investigations by performing both non-gel based and gel-based proteomic analyses on neural stem cell and tumor stem cell. These studies provide the first comprehensive, comparative, and quantitative analysis of neural stem cell and tumor stem cell total proteome alterations. Two-dimensional gel electrophoresis (2D) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry is used in gel-based approach. The technology with its high throughput, high sensitivity, high resolution, relative repeatability and its good match with mass spectrometry, is now the most common and basic method in protein separation. To complement and confirm our proteomic findings obtained via gel-based proteomic approach, we conducted simultaneous nongel-based proteomic analyses using isobaric tags for relative and absolute quantitation (iTRAQ) and quadrupole time-of-flight (Q-TOF). This approach combines the ability of iTRAQ to facilitate simultaneous protein abundance determination between different experimental conditions with the specificity of mass spectrometry for protein identification. The combined iTRAQ and 2D experiments identified a total of 244 altered expression proteins, including 116 differential expression proteins identified in 2-D PAGE,190 differential expression proteins identified in iTRAQ. There are 62 differential protein identified in both 2-D PAGE and iTRAQ. These proteins were mainly involved in protein synthesis, structural proteins, connexins, transcription and other processes.