TNF-a调控lncRNA-UTHC/NF-κB正反馈环路促进肝癌索拉非尼耐药的机制研究

Sorafenib is the first-line choice in the targeting therapy for hepatocellular carcinoma (HCC), However, the treatment efficiency of sorafenib is limited because of drug resistance. Our previous experiments have demonstrated that TNF-a is related with sorafenib resistance in HCC, but the regulating mechanisms remains unclear. To explore the molecular mechanisms, we applicated the lncRNAs microarray technology and screened the differential expressions of lncRNAs between sorafenib-resistant and sorafenib-sensitive HCC tissues. Results showed that the expression level of lncRNA-UTHC is higher in sorafenib-resistant HCC tissues than that in sorafenib-sensitive HCC tissues, accompanied with the high-expression of TNF-a. Further experiments indicated that sorafenib stimulates the TNF-a secretion, and subsequently up-regulates the expression of lncRNA-UTHC. Then, lncRNA-UTHC activates NF-κB signal pathway and prompts HCC cell proliferation and metastasis, thus causes drug resistance to sorafenib. Moreover, our experiments also suggested that inhibition of the NF-κB activation may down-regulate the expression of lncRNA-UTHC, and causes drug sensitive to sorafenib. On the basis of our previous studies, the current study will further confirm that TNF-a regulates lncRNA-UTHC/NF-κB positive-feedback signal pathway and prompts sorafenib resistance in hepatocellular carcinoma. This study will help to clarify the molecular mechanism of sorafenib resistance in the treatment of HCC, thus provide more scientific basis for the targeting therapy of HCC.

索拉非尼是治疗肝癌的一线靶向药物，但是由于肝癌对其耐药而影响疗效。我们前期研究显示，肝癌索拉非尼耐药与炎症因子TNF-a高表达相关，但机制不清。结合lncRNA芯片结果，我们发现索拉非尼耐药肝癌组织中TNF-a和lncRNA-UTHC（UTHC）表达水平均显著高于索拉非尼敏感肝癌组织；索拉非尼可刺激肝癌细胞中TNF-a分泌，进而上调UTHC表达，通过激活NF-κB通路促进细胞增殖和迁移，导致肝癌对索拉非尼耐药；而抑制NF-κB活性可下调UTHC表达，改善肝癌对索拉非尼敏感性。这提示，UTHC和NF-κB可能以正反馈环路的形式，参与了肝癌索拉非尼耐药。本项目拟在前期基础上，进一步从分子、细胞和动物水平，通过siRNA、RNA-CHIP、RIP等方法阐明TNF-a调控 UTHC/NF-κB正反馈环路介导肝癌索拉非尼耐药的具体机制及克服策略，项目的实施有望为提高肝癌靶向疗效提供新的科学依据。

索拉非尼是治疗肝癌的一线靶向药物，但是由于肝癌对其耐药而影响疗效。我们前期研究显示，肝癌索拉非尼耐药与炎症因子TNF-a高表达相关，但机制不清。结合lncRNA芯片结果， 我们发现索拉非尼耐药肝癌组织中TNF-a和lncRNA-UTHC(UTHC)表达水平均显著高于索拉非尼敏感肝癌组织;索拉非尼可刺激肝癌细胞中TNF-a分泌，进而上调UTHC表达，通过激活NF-κB 通路促进细胞增殖和迁移，导致肝癌对索拉非尼耐药;而抑制NF-κB活性可下调UTHC表达，改善肝癌对索拉非尼敏感性。这提示，UTHC和NF-κB可能以正反馈环路的形式，参与了肝癌索拉非尼耐药。.本项目在前期研究基础上，进一步从分子、细胞和动物水平，通过siRNA、RNA-CHIP、RIP等方法探索了TNF-a调控 UTHC/NF-κB正反馈环路介导肝癌索拉非尼耐药的具体机制及克服策略。首先，为明确TNF-α参与调控HCC细胞索拉非尼耐药及其相关的机制，本项目检测了HCC组织以及细胞中TNF-α的表达水平及其与索拉非尼耐药的相关性，并通过细胞以及动物实验明确了抑制TNF-α的表达与索拉非尼联合处理对HCC细胞增殖、凋亡以及侵袭转移等特征的影响；进而，本项目探索了TNF-a调控 UTHC/NF-κB正反馈环路介导肝癌索拉非尼耐药的具体机制及克服策略。与此同时，在项目实施期间，为更充分的探索非编码RNA参与调控HCC靶向耐药的相关机制，课题组通过生物信息学分析筛选与索拉非尼耐药密切相关的miRNA，并证实了miR-126-3p和miR-1226-3p两种miRNA与HCC索拉非尼耐药相关。上述研究发现为从非编码RNA角度探索HCC靶向治疗耐药机制，以及治疗新靶点的选择和提高靶向治疗疗效提供了新的科学依据。