Dissertation > Excellent graduate degree dissertation topics show

Transcriptional Regulation Mechanism of the Radiation-induced Hepatoma HepG2 Cells on IER5 Gene

Author: YinLingLing
Tutor: YangChuanJie；DingKuKe
School: Hebei Medical University
Course: Internal Medicine
Keywords: IER5 Primary liver cancer Radiation GCF Transcriptional regulation
CLC: R735.7
Type: Master's thesis
Year: 2011
Downloads: 20
Quote: 0
Read: Download Dissertation

Abstract

Primary hepatocellular carcinoma (HCC) is one of the common malignant tumors in China, the global HCC occurred in 55% of newly issued annually, the annual mortality accounted for a third of cancer mortality in China, a very severe form of liver cancer diagnosis and treatment ; common liver cancer non-surgical therapy: hepatic artery embolization, intratumoral ethanol injection, radiofrequency ablation, the effects are not ideal. Radiotherapy is one of the three means of cancer treatment, the recent years, with the development of three-dimensional conformal radiotherapy and intensity-modulated radiotherapy techniques, radiotherapy has become a powerful weapon of the treatment of liver cancer. One of the key issues of the sensitivity of tumor cells to radiation influence the effects of cancer radiotherapy, radiation sensitivity to radiation-induced expression of gene regulation, looking for tumor radiation-sensitive genes, clarify mechanism of radiation on the induction of gene expression and tumor radiation-sensitive the relationship between, for improving the effect of cancer radiotherapy and prolong the survival period of cancer patients is important. IER5 Immediate early response 5 short for belonging to the the early slow response gene family, the activation of early response genes to cells and chromosomes reaction to external stimuli first and most important step. Studies have shown the IER5 gene is present in a number of tumor and normal tissue, and its expression changes will affect the cell cycle and apoptosis. In 2005, we and Kis almost simultaneously using gene chip technology screening of the radiation effects of a number of genes, the IER5 gene upregulation was found after radiation. Therefore, we began to focus on the gene, gene silencing and overexpression has the use of technology to conduct research on the radiation effects of IER5 genes and their biological functions, and also to determine the radiation response of IER5 gene promoter region. It was found that radiation induced IER5 mRNA levels were up-regulated; gene silencing (RNAi) to promote cell growth, and radiation showed antagonistic; overexpression can inhibit cell growth, and promoting radiation-induced apoptosis, bioinformatics analysis of the most likely range of prediction IER5 gene promoter-408bp-238bp. These experiments showed that IER5 gene is a cancer radiotherapy-related gene, its biological function similar to tumor suppressor genes in the radiation case. Because of this, we do in-depth exploration decided on IER5 gene, intends to adopt the methods of bioinformatics, molecular and cellular biology, the use of HepG2 cells to study IER5 gene transcriptional regulation mechanism, designed to reveal IER5 gene transcription in liver cancer radiotherapy regulatory mechanism, to provide a theoretical basis for future clinical liver cancer radiosensitization and drug development. The above findings prompted us IER5 genes may be liver cancer radiation sensitive gene, should carry out more in-depth research. The Objective: IER5 the belong to the early response genes, whose role is similar to tumor suppressor genes upregulated and promote apoptosis after radiation. Currently, little research at home and abroad IER5 genes the retrieved literature mostly elaborate IER5 gene structure information and biological function. The purpose of this study is the analysis of transcription factor the IER5 promoter transcriptional activity, designed to reveal the mechanism of the IER5 the transcriptional regulation of genes in liver cancer radiotherapy, the theoretical basis for future clinical liver cancer radiosensitization and drug development. Method: First of all, according to the website http://thr.cit.nih.gov/molbio/proscan potential cis-acting elements contained the IER5 gene promoter analysis results build IER5 gene luciferase reporter vector using promoter mutation analysis of experimentally determined IER5 gene promoter cis-acting element within the sub-types and distribution. Second, co-transfected HepG2 cell lines using the method of analysis of the transcriptional activity of radiation before and after the transcription factor IER5 gene promoter; utilization the EMSA method of analysis corresponding transcription factor GCF in vitro whether and IER5 the gene promoter binding sites and radiation before and after the corresponding binding sites for transcription within the factor with IER5 gene promoter binding with or without changes; CHIP method to determine the corresponding binding sites of the transcription factor GCF body whether with IER5 the gene promoter binding and radiation before and after the transcription factor IER5 gene promoter corresponding binding site whether the change. Results: 1 IER5 gene promoter -388 to -382 region, the binding sites within the -274 to -270 region GCF mutation can cause the promoter transcription activity was significantly increased (P LT; 0.05) before and after irradiation, the transcription activity significantly ( P lt; 0.05); NFI binding sites within the -362 to -357 region mutations can cause promoter transcriptional activity was significantly decreased (P lt; 0.05), and transcriptional activity changes before and after irradiation significantly (P lt; 0.05); - TTR inverted-repeat binding sites in the region of 351 to -345 mutation promoter transcription activity of small (P gt; 0.05) and did not change significantly (P gt; 0.05) before and after irradiation. 2 transcription factor GCF in vitro with IER5 of gene promoter -388 to -382 region, the binding sites within the -274 to -270 region GCF bonded to each other, and under irradiation with the radiation dose increases (0Gy, 2Gy, 4Gy ), transcription factor GCF promoter corresponding binding region combined with diminished capacity. 3 transcription factor the GCF and IER5 gene in HepG2 cells and to start sub -388 to -382 region GCF binding sites within the -274 to -270 region combined with each other, and with the increase of radiation dose (0Gy 2Gy 4Gy) The transcription factor GCF corresponding promoter binding regions combined with diminished capacity. Conclusion: 1 IER5 gene promoter -388 to -382 and -274 to -270 region exist from the negative regulatory role of the transcription factor GCF cis-acting elements and inhibition reduced with the increase of radiation dose transcription factor GCF; -362 ~ -357 regional presence to play a positive role in regulation of transcription factors NFI cis-acting elements, and to promote the enhanced role of transcription factor NFI with the increase of radiation dose. Interaction of the cis-acting elements within the 2 transcription factor the GCF through with IER5 of gene promoter and inhibiting expression of the gene, further in transcriptional regulation IER5 play negative regulatory role to play a negative regulatory role, and the transcription factor GCF with significantly weakened by the increase in the radiation dose.

Transcriptional Regulation Mechanism of the Radiation-induced Hepatoma HepG2 Cells on IER5 Gene

Abstract

Related Dissertations