靶向泛素交联酶UBE2D3调控肿瘤放射敏感性的机制研究

Our previous study showed that telomeres and telomerase were related to the cancer radiosensitivity. UBE2D3 was found as interaction protein with hTERT by yeast two-hybrid system, which was could down regulate hTERT and enhance cancer radiosensitivity in MCF-7 cells. Thus, we speculate that UBE2D3 may play a vital role in cancer radiosensitivity. To confirm this hypothesis，the project intends to study relationship between the UBE2D3 and radiosensitivity by measuring the expression of UBE2D3 in cell lines with different radiosensitivity, and then investigate the effect of UBE2D3 on the cancer radiosensitivity by the model with overexpression and silence of gene UBE2D3 in human cancer cells. We will explore the mechanism of UBE2D3 regulating the radiosensitivity of cancer cells through detecting hTERT ubiquitination, telomere homeostasis related pathways, cell growth and apoptosis signaling pathway. Meanwhile, we use animal tumor models, tumor specimens library data and follow-up data analysis to further study the effect of UBE2D3 on the radiotherapy in vivo, and to clarify the key role of ubiquitination mediated by UBE2D3 in regulation of radiosensitivity. These will enrich the theory of radiosensitivity regulation and provide radiosensitization targets and predictors of radiosensitivity in clinical radiotherapy, which will provide a basis for decision making and experimental support for individualized treatment.

我们前期研究发现端粒、端粒酶和放射敏感性有关，应用酵母双杂交系统筛选出与端粒酶亚单位hTERT相关的泛素交联酶UBE2D3 ,发现UBE2D3与hTERT直接相互作用，干扰UBE2D3能上调hTERT表达,同时乳腺癌细胞MCF-7放射抗拒；故推测UBE2D3可能是调节肿瘤放射敏感性的靶点。本项目拟研究UBE2D3在不同放射敏感性细胞株中的表达差异，并建立过表达或基因沉默UBE2D3的稳定转染株，研究UBE2D3对放射敏感性的影响；通过分析UBE2D3对hTERT的泛素化水平、端粒稳态维持与调节通路、DNA损伤修复通路及细胞生长凋亡等通路的调节，探索UBE2D3调节肿瘤细胞放射敏感性的可能机制；建立动物移植瘤模型并结合肿瘤标本库数据和随访数据分析，明确UBE2D3与放疗疗效的关系，阐明UBE2D3在放射敏感性泛素化调节中的作用，为临床放疗提供新的增敏靶点和放射敏感性预测指标。

我们前期研究发现端粒、端粒酶和放射敏感性有关，应用酵母双杂交系统筛选出与端粒酶亚单位hTERT 相关的泛素交联酶UBE2D3 ,发现UBE2D3 与hTERT 直接相互作用，干扰UBE2D3 能上调hTERT 表达,同时乳腺癌细胞MCF-7 放射抗拒；故推测UBE2D3 可能是调节肿瘤放射敏感性的靶点。本项目拟研究UBE2D3 在不同放射敏感性细胞株中的表达差异，并建立过表达或基因沉默UBE2D3 的稳定转染株，研究UBE2D3 对放射敏感性的影响；通过分析UBE2D3 对hTERT 的泛素化水平、端粒稳态维持与调节通路、DNA 损伤修复通路及细胞生长凋亡等通路的调节，探索UBE2D3 调节肿瘤细胞放射敏感性的可能机制；建立动物移植瘤模型并结合肿瘤标本库数据和随访数据分析，明确UBE2D3 与放疗疗效的关系，阐明UBE2D3 在放射敏感性泛素化调节中的作用，为临床放疗提供新的增敏靶点和放射敏感性预测指标。