Expression And Significance Of CRY1 In Human Brain Gliomas

PrefaceGliomas are the most common familiar tumors in the central nervous system, accounting for 40%-43% of primary tumors. Currently, several promising genes relating to the generation and progression of tumor cells and the prognosis of patients have been identified with the development of molecular biology and molecular genetics. Gene therapy is being pursed in preclinical investigations in order to increase the efficiency of glioma cure. Circadian rhythm exists ubiquitously in all most all organisms. Breakthrough has made in the investigation of circadian rhythm because of the discovery of circadian rhythm genes and its regulating mechanisms. Circadian rhythm genes play an important role in the tumor generation and progression by regulating oncogenes, anti-oncogenes, cell cycle, vascular endothelial growth factor and endocrine pathway.The generation of tumor involves many genes, including the inactivation of anti-oncogenes and activation of oncogenes. CRY1 gene was found in the process of studying the DNA repairing photolyase in mammals. It belongs to vegetative blue light receptors and photolyase family. CRY1 gene, the major circadian rhythm gene, is the exclusive negative regulating factor in the feedback loop, which determines the gene expression in certain time, especially ensuring the homeostasis pathway to work properly. CRY1 protein, a kind of nucleoprotein, can stabilize the structure of per protein and also can combine it directly and then transmit it from plasma to the core. CRY1 gene participates in the negative feedback loop of circadian rhythm by inhibiting Clock-Bmall dependent gene transcription through affecting Clock-Bmall-Ebox pathway directly or indirectly. The latter can induce cell carcinogenesis by down-regulating anti-oncoge expression and up-regulating oncogene expression. Further investigation in CRY1 gene may predict the effects of this gene in the generation and progression of glioma, so the objective of this study is to analyze the gene and protein of CRY1 in human glioma in order to identify the effects of CRY1 gene in the generation and progression of glioma.Materials and MethodsSixty two cases of gliomas and normal brain tissues were derived from clinical operation. None of the patients had received radiotherapy or chemotherapy before operation. All specimens were kept under -70 centigrade degrees. Western-blot and semi-quantity RT-PCR analysis were used to detect mRNA and protein expression of CRY1.ResultsThe expression value of CRY1 protein and mRNA is statistically higher than those in normal brain tissues. The CRY1 mRNA expression value in human gliomas is 2.77±0.16 while in normal brain tissue is 1.91±0.23 detected by RT-PCR method. The CRY1 protein expression value in human glioma is 2.94±0.46 while in normal brain tissue is 1.87±0.33 detected by Western-blot method. The lower expression of CRY1 gene in human glioma has a correlation with the pathological grades of glioma. The expression of CRY1 gene in high grades of gliomas (III,IV) is statistically lower than that in low grades of gliomas (I, II). So the expression of CRY1 gene in gliomas is decreasing with the increasing of tumor malignance.ConclusionsThe expression value of CRY1 in human glioma is statistically lower than that in normal brain tissue both in mRNA and protein level. The lower expression has a correlation with the pathological grades of glioma. So CRY1 gene may be the important factor of carcinogenesis and it may participate in the generation and progression of glioma.