| Neurospongioma, also called gliocytoma, referred to as glioma, neuroectodermalorigin, is the most common primary malignant brain tumor. According to2007WHOclassification of tumors of the central nervous system and Chinese central nervoussystem glioma diagnosis and treatment guidelines (2012version), common types ofgliomas included low-grade astrocytomas (LGA), anaplastic astrocytoma (AA),Oligodendroglioma tumors (OG) and glioblastomas multiforme (GBM). There arereports in the literature on the efficacy of glioma, even in modern growing medicaltechnology, the use of systemic chemotherapy+surgery+radiotherapy (orradiosurgery); the average survival time of patients with gliomas is only12-18months. Therefore, extending time of survival and improving quality of life ofpatients have become a serious problem.Basic research of glioma chemotherapy is one of the most important internationalresearches. Biological treatment is an important aspect of chemotherapy. Biologicaltreatment has increasingly become a hot spot of the glioma study at present. Themain goal of Glioma biological treatment is to suppress replication of glioma DNAand the formation of RNA.The synthesis process of RNA includes the transcription process andpost-transcriptional processing&modification (e.g.: RNA editing and RNA splicing,etc.). HOX genes (homeobox genes) are master genes of transcription process. HOXgenes involve in formation and development of many tumor of human beings.Researches on HOX genes in the formation and development of glioma havereceived increasing attention, but the relationship between39HOX genes and glioma is not quite clear. RNA editing process is the cause of the different expressionof protein levels and gene level of DNA genetic information. Thus, during the past10years, scholars have been studying the relationship between RNA editing and avariety of tumors. RNA editing process is mainly regulated by RNA editing enzyme(adenosine deaminase acting on RNA, ADAR). In the human brain, ADAR is mainlyADAR1, ADAR2and ADAR3; ADAR2plays a main role in glioma. According tothe current literatures, the relationship between ADAR2expression as well as theoccurrence and development of gliomas is unclear. Therefore, to further explore newgenes of the HOX gene family associated with gliomas and discusses the mechanismof ADAR2working on the occurrence and development of gliomas, is helpful toprovide a new theoretical basis for the biological treatment of glioma patients.The first part of the experiment is to study expression of ADAR2mRNA innormal human brain astrocytes lines (NHA), human glioma cell lines and gliomatissue especially GBM tissue, and the patient’s clinical and characteristics forcomparison. The purpose is to observe RNA editing process, the mechanism ofADAR2mRNA abnormal expression and the relationship among abnormalexpression of ADAR2mRNA, peritumoral edema and invasiveness. We determinedADAR2mRNA expression in NHA, in astrocytoma cell line SHG44and in humanglioblastoma cell lines U251and BT325by quantitative real-time RT-PCR(qRT-PCR). Analyzed the alternative splicing variant (ASV) of ADAR2in gliomas.We then use malignant features of glioblastomas to observe the relationship amongabnormal expression of ADAR2mRNA, peritumoral edema and invasiveness. Theresults are as follows:(1) there are all expressions of ADAR2mRNA in NHA, inastrocytoma cell line SHG44and in human glioblastoma cell lines U251and BT325.There is relatively high expression in U251. There is relatively low expression inSHG44. Differences of expression of ADAR2mRNA among the groups were notsignificant. The difference of expression of ADAR2mRNA in human glioma tissueand normal brain tissue was not significant.(2) The total RNA extracted from humanbrain glioblastoma line U251and BT325were amplified by RT-PCR which showed that there was an ASV in the brain tumor glioblastoma line U251and BT325. Theanalysis showed that the ASV was inserted after the first28nucleotides of thecoding region, and was a length of47nucleotide bases (bp).(3) Analysis therelationship among the expression of ADAR2ASV and patients with GBMperitumoral edema, tumor invasion and survival period, the peritumoral edema andtumor invasiveness of patients with ADAR2ASV (+) was significantly higher thanpatients with ADAR2ASV (-), the survival period of patients with ADAR2ASV (+)was significantly lower than patients with ADAR2ASV (-).The second part of the experiment is to study the expression of HOXA10mRNA,HOXB1mRNA, HOXC6mRNA and HOXD13mRNA in normal brain tissue,different glioma cell lines and glioma tissues. The purpose is to observe therelationship between4HOX genes and occurrence and malignancy of gliomas. Wedetermined the expression of HOXA10, HOXB1and HOXD13in HA1800, U87andU251by qRT-PCR. We analyzed the expressions of HOXA10mRNA, HOXB1mRNA, HOXC6mRNA and HOXD13mRNA in normal human astrocytes HA1800,normal brain tissue (parietal, frontal and gliosis tissues), glioma cell lines and gliomatissues of different grades by RT-PCR and image analysis. The results are:(1) thereare high expressions of HOXA10mRNA in U87and U251, the difference was moresignificant than in normal human astrocytes HA1800(P<0.01). There are highexpressions of HOXA10mRNA in glioma tissues, and the difference was moresignificant than in normal brain tissue (parietal, frontal and gliosis tissues)(P<0.05).The difference was not significant between glioma I-II and glioma III-IV (P>0.05).(2) There are high expressions of HOXB1mRNA in U87and U251, the differencewas significant compared with normal human astrocytes HA1800(P<0.01). Thereare high expressions of HOXB1mRNA in glioma tissues, and the difference wassignificant compared with normal brain tissue (parietal, frontal and gliosis tissues)(P<0.05). The difference was not significant between glioma I-II and glioma III-IV(P>0.05).(3) There are high expressions of HOXC6mRNA in glioma tissues, thedifference was significant compared with normal brain tissue (parietal and gliosis tissues)(P<0.05). The difference was not significant compared within normal brainfrontal tissue (P>0.05). The difference was not significant between glioma I-II andglioma III-IV (P>0.05).(4) There are high expressions of HOXD13mRNA in U87and U251, the difference was significant compared with normal human astrocytesHA1800(P<0.01). The difference was not significant compared with normal braintissue (parietal, frontal and gliosis tissues)(P>0.05). The difference was notsignificant between glioma I-II and glioma III-IV (P>0.05).With comprehensive the results of two parts, the experimental conclusions are:(1)in glioma cells and tissues, ADAR2produces a length of47ASV in the precursormRNA editing process itself; the ASV may be related to the grade of gliomamalignancy and may become a new target for individualized treatment.(2) HOXB1is a novel HOX gene, which maybe have a correlation with the occurrence anddevelopment of gliomas. |
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