结肠癌细胞核内S100P转录调控POTEE表达对促进肿瘤增殖的作用机制

Transcriptional regulation of cancer-related gene expression is an important way to affect the tumor biological function, and a key step to explain the process of cancer development. In our previous study, we found that S100P was an overexpressed protein in colon cancer. High expression of S100P regulated by the transcription factor SOX9, activated RAGE/ERK pathway, promoted the proliferation, invasion and metastasis of colon cancer. And we also found that S100P was expressed in abundance in the nucleus, besides distributed in the cytoplasm of colon cancer cells. We used ChIP-sequencing to explore the function of intranuclear S100P in transcriptional regulation. It showed that intranuclear S100P could be combined with POTEE promoter. To analyse the role of POTEE transcriptional regulated by S100P in the colon cancer, this study will validate the relationship between S100P and POTEE, detect the effect of POTEE in proliferation and apoptosis of colon cancer cells, clarify the meaning of POTEE in S100P-mediated proliferation of colon cancer, and discover POTEE-related pathways by constructing S100P or POTEE interfered and overexpressed colon cancer cell lines. In the end, the gene expression regulating function of S100P in the nucleus would be verified. The biological function of POTEE and related mechanisms in the colon cancer would be clarified. The results of this study could enrich the molecular theories of S100P in colon cancer, and might offers a new strategy for targeted cancer therapy against the proliferation.

肿瘤相关基因表达的转录调控是影响肿瘤生物学功能的关键环节。在前期研究中，我们发现结肠癌中高表达的S100P受转录因子SOX9调控，通过激活RAGE/ERK通路，促进肿瘤的增殖与侵袭转移。同时，S100P除分布于结肠癌细胞细胞浆中，在细胞核内也有丰富的表达。为探索肿瘤细胞核内的S100P是否具备转录调控功能，我们通过ChIP-sequencing分析及筛选发现核内S100P可与POTEE启动子相结合。为进一步分析核内S100P转录调控POTEE在结肠癌增殖凋亡中所发挥的作用，本项目将通过构建S100P、POTEE干扰及过表达结肠癌细胞株，验证结肠癌细胞核内S100P的基因表达调控功能，阐述受核内S100P转录调控的POTEE基因在结肠癌增殖中的作用及其分子机制，阐明POTEE在S100P促结肠癌增殖中的意义与地位，补充及完善结肠癌中S100P分子作用理论，为对抗结肠癌的增殖提供新的治疗策略。

第一部分：异常基因表达在结直肠癌（CRC）的发展中起关键作用。在本研究中，我们证实了POTEE-POTE锚蛋白域家族E成员，在结直肠肿瘤中显著上调，并可作为结直肠癌患者生存预后的预测因子。在CRC细胞中，POTEE作为原癌基因，可以促进细胞生长，促进细胞周期进程，抑制细胞凋亡并提高异种移植肿瘤的生长。在机制研究上，我们使用三代测序基因芯片证明了POTEE/SPHK1/p65信号转导轴可作为影响CRC细胞的生物学功能的下游。 进一步的评估表明，POTEE的过表达可以增加SPHK1的蛋白合成，进而促进p65蛋白的磷酸化。综上所述，我们的研究结果表明，POTEE/SPHK1/p65信号轴可以促进结直肠癌的发生发展，而POTEE可能可以作为诊断和干预结直肠癌的新型生物标志物。.第二部分：SNX1是sorting nexin家族的成员，与肿瘤的发展有关。但是，尚无结直肠癌（CRC）NX16功能报道。在本研究中，CRC组织中SNX16的表达明显上调。 SNX16的mRNA水平上调预示了CRC患者的不良生存预后。功能实验表明，SNX16可以在体外和体内促进CRC细胞的生长。敲低SNX16会诱导细胞周期停滞和凋亡SNX16-eEF1A2的相互作用可以抑制eEF1A2的降解和泛素化，然后激活下游c-Myc信号传导。通过研究表明，SNX16/eEF1A2/c-Myc信号轴可以促进结直肠肿瘤的发生，而SNX16可能潜在地成为诊断和干预结直肠癌的新型生物标志物。.第三部分：CD36在结直肠癌发生发展中所发挥的作用仍不明确。我们前期研究促癌基因S100P的过程中，在应用大数据分析、基因芯片筛选、组织验证过程中额外发现，CD36在结直肠癌中表达显著下调，并对结直肠癌的进展起到抑制作用。