淋巴细胞特异性转录因子Aiolos在肺癌转移中的功能和调控研究

逃逸失巢凋亡是实体肿瘤细胞转移过程中的重要分子生物学事件之一，我们前期工作表明，正常表皮细胞中定位于粘附斑的衔接蛋白p66Shc能够在细胞脱离基质时感受张力变化启动失巢凋亡，该蛋白在肺癌细胞中的表达缺失是导致肺癌细胞发生转移的主要因素，而生理状态下仅表达于淋巴细胞的转录因子Aiolos在肺癌细胞中的异位表达是抑制p66Shc转录的原因，这一发现暗示着实体肿瘤细胞很可能通过获得造血细胞特有蛋白而改变自身的特性包括对失巢凋亡的敏感性，进而影响肿瘤的发生发展和侵袭转移。本项目将利用细胞三维培养、单细胞RT-PCR、3C等多种技术研究Aiolos在肺癌发生发展中的功能和调控，包括Aiolos异位表达对细胞粘附相关特性的影响及机理以及与临床肺癌远端转移的相关性、并探讨导致Aiolos在肺癌细胞中异位表达的表观遗传机制。研究结果将有助于理解实体肿瘤转移的分子机制,为实体肿瘤的靶向诊疗提供实验基础。

Parenchymal cells have strong anchorage requirements which prevent tissue disorganization and restrict long-range movement of differentiated cells. Pathologic loss of such requirements is required for metastatic behavior in transformed cancer cells. Our preliminary data showed that adaptor protein, p66Shc, localizes to focal adhesions, reports cell detachment and induces anoikis. p66Shc is frequently repressed in metastatic human lung cancer cells and when re-expressed, it completely blocks metastasis of Lewis Lung Carcinoma cells （which do not express p66Shc） in mice, indicating its ability to act as a powerful metastasis suppressor in vivo. Interestingly, the lymphocyte specific zinc finger transcription factor Aiolos, which is coded by IKZF3, is ectopically expressed in solid tumors and plays a critical role in suppressing p66Shc expression. In addition, the expression of Aiolos in human lung cancer tissues predicts survival disadvantage. These preliminary data provide a potential link between hematopoietic specific regulatory network and anchorage independent behavior in metastatic cancer. Here, the objective of this proposal is to systematically focus on the function and regulation of Aiolos in human solid tumors derived from lung using multiple techniques including RNA interference, immunohistochemistry, 3C, matrigel 3D culture, single cell RT-PCR and CHIP. Specifically, we will dissect the role of ectopic expression of Aiolos in cell adhesion related behavior and its mechanism, the connection between Aiolos expression level with distal metastasis of lung cancer, and the environmental factors that contribute to the ectopic expression of Aiolos. Hopefully we may gain significant insight into the change of regulatory network associated with tumorigenesis and metastasis in solid tumors. Also, a better understanding of the mechanisms underlying anoikis resistance could help to prevent solid tumor progression and metastasis.