CCDC65与MYH9相互作用调控GSK3β去泛素化抑制鼻咽癌生长、转移和化疗抵抗性的研究

CCDC65 is one member of the coiled-coil domain family and its role is never reported in tumors. Our preliminarily study indicated that CCDC65 as a potential tumor suppressor reduced cell proliferation,migration,and invasion by suppressing cell cycle and EMT signals in Nasopharyngeal carcinoma(NPC). Further, Mass Spectrometry and CoIP assays revealed that MYH was a potential protein interacting with CCDC65.Furthermore, MYH9 was antagonized by CCDC65 possible via suppressing PTEN/PI3K/AKT/c-Jun signal. In subsequent study, MYH9 was observed to the combination with GSK3β. In addition, MYH9 increased the GSK3βubiquitination level and suppressed its protein expression. Subsequent studies will confirm that CCDC65 not only interacts with MYH9, but it suppresses the expression of MYH9 through PTEN/PI3K/AKT/c-Jun signal, which reduces the combination of MYH9 with GSK3β and the GSK3βubiquitination level and further decreases the transition of β-catenin-mediated cell cycle and EMT and thus suppresses cell growth,metastasis, and chemotherapy resistance. Our study firstly reveals CCDC65 as a potential tumor suppressor, which will provide the new clue for further understanding the mechanism of NPC. pathogenesis.

CCDC65为卷曲螺旋蛋白家族成员之一，其在肿瘤中尚未有报导。我们初步发现CCDC65作为抑癌候选基因抑制细胞周期和EMT信号，从而降低了鼻咽癌细胞增殖、游走和侵袭能力。进一步质谱及免疫共沉淀分析揭示MYH9为CCDC65候选直接作用蛋白，且CCDC65可能通过调节PTEN/PI3K/AKT/c-Jun信号拮抗其表达。随后研究发现MYH9能与GSK3β结合并在蛋白水平上促进其降解，激活下游β-catenin的表达。后续研究将进一步明确：CCDC65在鼻咽癌中不但直接与MYH9相互作用，而且通过调控PTEN/PI3K/AKT/c-Jun信号抑制其表达，从而降低MYH9与GSK3β的结合及其泛素化水平，通过抑制β-catenin所介导的细胞周期和EMT转化，降低了鼻咽癌细胞生长、转移和化疗抵抗能力。我们将首次揭示CCDC65作为候选抑癌基因在鼻咽癌中的机制， 为探索鼻咽癌发病机理提供了新线索。

在本研究中，我们阐明CCDC65抑制鼻咽癌（NPC）发生发展的机理及其分子机制。首先，我们发现CCDC65在体外和体内均有效抑制了肿瘤的增殖能力。机理研究表明，CCDC65通过下调β-catenin，抑制了鼻咽癌细胞的G1/S转化。此外，我们观察到CCDC65与MYH9及FBXW7相互作用，促进了β-catenin的泛素化降解，从而阻断了下游细胞周期转化，抑制鼻咽癌细胞的增殖能力。进一步，我们明确MYH9作为候选癌基因能拮抗FOXO1和MAP2K4对鼻咽癌肿瘤干性和EMT信号抑制的潜能，从而诱导鼻咽癌生长、转移和顺铂化疗抵抗。. 在随后的研究中，我们也发现CCDC65在肺腺癌中呈现出显著下调，体内外实验发现CCDC65能够有效抑制肺腺癌的增值能力。分子机制显示CCDC65通过与FBXW7及c-Myc相互作用，促进c-Myc的泛素化降解。我们还发现c-Myc作为转录因子，能够结合到ENO1的启动子区，调节ENO1的转录。下调的c-Myc减弱了ENO1/AKT1信号的激活，降低了细胞周期转化，抑制肺腺癌细胞的增殖。