TP63α/Sonic Hedgehog调控慢性N-二甲基亚硝胺暴露诱导肝癌干细胞的分子机制及大蒜活性成分二烯丙基三硫化物的干预作用

Nitrosocompounds are critical dietary risk factor of liver cancer. Cancer stem cells (CSCs) play crucial role in the formation and development of cancer. To date, the action of nitrosocompounds on the induction of liver CSCs, the underlying mechanisms as well as diallyltrisulfede (DATS) intervention has not been defined. In our preliminary studies we found that chronic N-nitrosodimethylamine (NDMA) exposure induced malignant transformation of human normal liver cells (LO2), among which liver CSCs activity existed, along with upregulation of TAp63α, downregulation of ΔNp63α, and activation of Sonic Hedgehog signaling pathway. We also showed that DATS inhibited sphere formation capacity of malignant transformated LO2 cells cultured in serum-free-medium, reduced liver CSCs markers’ expression, suppressed TAp63α expression, upregulated ΔNp63α level, and prevented the activation of Sonic Hedgehog pathway. However, the role and regulation of TP63α/Sonic Hedgehog axis in chronic NDMA-induced liver CSCs and DATS intervention is unknown. Using both in vitro and nude mouse models, the present research will for the first time investigate the role of TP63α/Sonic Hedgehog in NDMA -induced liver CSCs and its regulatory mechanism. Furthermore, this research will illustrate the function of TP63α/Sonic Hedgehog in the interventional effects of DATS on NDMA-induced liver CSCs. Finding from this research will provide new insights into the molecular mechanisms of TP63α/Sonic Hedgehog in regulating NDMA-induced liver CSCs and search for new approach for its target intervention

亚硝基化合物是引起肝癌的关键膳食因素。肿瘤干细胞对肿瘤的发生、发展起决定性作用。目前从肝癌干细胞角度探讨亚硝基化合物诱发肝癌的分子机制及其干预研究未见报道。我们前期研究发现慢性N-二甲基亚硝胺暴露能诱导人正常肝细胞恶性转化且具有肝癌干细胞特性，此表型与上调TAp63α、下调ΔNp63α及激活Sonic Hedgehog通路有关；大蒜主要活性成分二烯丙基三硫化物（DATS）可抑制恶转的肝癌干细胞活性。然TP63α/Sonic Hedgehog是否真正调控慢性N-二甲基亚硝胺诱导肝癌干细胞的活性及DATS的干预效应尚属未知。本课题采用体外细胞模型和动物模型相结合，创新性地探讨TP63α/Sonic Hedgehog通路调控N-二甲基亚硝胺诱导肝癌干细胞的作用机制，并在此基础上研究DATS的干预作用。旨在从肝癌干细胞视角探索亚硝基化合物诱发肝癌的分子机制并为其靶向干预提供新的重要科学依据。

亚硝基化合物是引起肝癌的关键膳食因素。肿瘤干细胞对肿瘤的发生、发展起决定性作用。二烯丙基三硫化物（DATS）是大蒜中具有抗癌作用的主要活性成分。迄今从肿瘤干细胞角度探讨亚硝基化合物诱发肝癌的分子机制及其干预研究尚无研究报道。本课题采用二甲基亚硝胺(NDMA) 慢性暴露诱导人正常肝细胞恶性转化模型，研究探讨TP63α/Sonic Hedgehog轴对慢性NDMA暴露诱导肝癌干细胞的调控作用及其调控机制，并在此基础上研究DATS对NDMA诱导恶转肝癌干细胞的干预作用以及TP63α/Sonic Hedgehog轴在DATS干预效应中的作用。本研究发现慢性NDMA暴露诱导恶转肝癌细胞具有肝癌干细胞特性，高表达TAp63α及低表达ΔNp63α，且Sonic Hedgehog信号通路异常激活。TP63α及Sonic Hedgehog信号对维持NDMA恶转肝癌干细胞活性具有重要作用。TAp63α激活而ΔNp63α抑制Sonic Hedgehog信号通路。我们在干预研究中首次探讨了TP63α/Sonic Hedgehog信号在DATS抑制NDMA恶转肝癌干细胞活性中的作用。结果表明DATS具有显著抑制NDMA恶转肝癌干细胞活性的效应；DATS下调TAp63α表达、上调ΔNp63α表达、抑制Sonic Hedgehog信号通路。 进一步研究表明，TP63α/Sonic Hedgehog轴介导DATS对NDMA恶转肝癌干细胞的干预作用。我们同时拓展研究了PEITC对NDMA恶转肝癌干细胞的干预作用机制。综上所述，本项目研究为深入探讨亚硝基化合物诱发肝癌干细胞的调控机制和其关键靶点，进而为以机制为导向的干预研究提供了新的重要科学依据和策略。