肝炎-肝癌恶性转化中肝癌干细胞干性调控的炎性因子和调控网络

It is hypothesized that a rare subset of cancer cells, often operationally referred to as cancer stem cells (CSCs) or tumor-initiating cells, are responsible for sustaining tumor growth and recurrence. It is well established that many inflammation-related molecules are actively involved in the malignant transformation process during the progress of hepatitis-cirrhosis-hepatocellular carcinoma resulting from hepatitis B infection. However, how these inflammation-related molecules activate cancer stem cells remains elusive. We have previously identified a population of liver CSCs that expressing the isoform 5 of α2δ1, which is encoded by CACNA2D1, a composing subunit of a voltage-gated calcium channel. The α2δ1-positive liver CSC population was found to be a subset with the highest tumorigenic potential of known liver cancer stem cell population defined by the marker CD13, CD133, or EpCAM. Overexpression α2δ1 in non-liver CSCs could result in enhanced hepatosphere-forming ability of these cells with elevated intracellular calcium level, suggesting the acquirement of self-renewal property. Furthermore, α2δ1 is essential in Ca2+ signaling and maintenance of CSC properties including the self-renewal capability, suggesting that α2δ1 could serve as a therapeutic target in the treatment of hepatocellular carcinoma. Compared with α2δ1-negative hepatocellular carcinoma cells, a lot of cytokines and chemokines related to inflammation such as CXCL11, IL12A, and TNFSF13B were found to be highly expressed in α2δ1-positive liver CSCs as revealed by RNA-seq. Furthermore, the expression of these molecules was controlled by α2δ1, which suggest that these molecules might be involved in the CSC properties’ regulation of α2δ1-positive liver CSCs. In this project, we are going to investigate how the expression of these molecules was correlated with the progression of hepatitis-cirrhosis-hepatocellular carcinoma and what the regulation mechanism(s) is underlying their expression. Furthermore, the roles and underlying molecular mechanism(s) in the acquirement and maintenance of liver CSC properties are also to be determined. Hopefully, we can reveal the signaling network and some key points involved in the determination and maintenance of the self-renewal property of these liver CSCs during the transition from hepatitis B infection to hepatocellular carcinoma. This study would contribute to the understanding of the malignant transformation molecular mechanisms resulting from the nonresolving inflammation with hepatitis B infection and would advance the development of prognostic and therapeutic strategies.

癌干细胞（CSC）被认为是支持肿瘤发生发展的源动力，乙肝病毒感染所致肝炎-肝硬化-肝细胞癌的恶性转化涉及大量炎性因子的分泌，这些炎性因子如何在演变过程中活化CSC并维持其干性尚存大量未知。我们前期工作发现电压依赖性钙通道α2δ1（亚型5）是肝CSC的功能性标志物和治疗靶点，α2δ1阳性CSC是多个已报道肝CSC共有的细胞亚群。与非CSC相比，α2δ1阳性CSC高表达CXCL11、IL12A、TNFSF13B等炎性相关分子且表达受α2δ1调控。本课题拟探讨这些因子在肝炎-肝硬化-肝细胞癌的恶性转化过程中表达调控的规律、在α2δ1阳性CSC干性获得与维持中的作用、机制和调控网络，以期从肝癌干细胞的活化角度揭示乙型肝炎病毒感染所致的非可控性炎症在向肝细胞癌恶性转化中的关键分子，并阐明其作用的机制和调控网络，为恶性转化预警标志物和干预治疗靶点研究提供线索。

癌干细胞（CSC）被认为是支持肿瘤发生发展的源动力，乙肝病毒感染所致肝炎-肝硬化-肝细胞癌的恶性转化涉及大量炎性因子的分泌，这些炎性相关因子如何在演变过程中活化CSC并维持其干性尚存大量未知。我们前期工作发现电压依赖性钙通道α2δ1（亚型5）是肝CSC的功能性标志物和治疗靶点。与非CSC相比，α2δ1阳性CSC高表达CXCL11等炎性相关分子。本课题对CXCL11在α2δ1阳性CSC的干性获得与维持中的作用和调控的分子网络进行了研究。研究结果表明，α2δ1阳性CSC自分泌CXCL11,通过其受体CXCR3激活ERK1/2信号通路，调控包括ISL1、LOX、CACNA2D1等与干性调控相关的基因的表达，从而在α2δ1阳性CSC自我更新和成瘤能力的获得与维持中发挥重要作用。ISL1作为超增强子激活CACNA2D1等干性相关基因的表达在肝癌CSC干性获得与维持中发挥作用。本课题还揭示了LOX可以通过交联胶原形成僵硬的微环境参与α2δ1阳性CSC干性的获得与维持。该研究从肝癌干细胞的活化角度揭示了乙肝病毒感染所致的非可控性炎症向肝细胞癌恶性转化的关键分子，阐明了作用的机制和调控网络，为恶性转化预警标志物和干预治疗靶点研究提供了线索。