亚甲基四氢叶酸脱氢酶2是异质性细胞叠套结构形成的负调控分子

MTHFD2 Is a Negative Regulatory Molecule for the Formation of Heterotypic Cell-in-Cell Structures

异质性细胞叠套结构(heterotypic cell-in-cell structure,heCICs)介导独特的非自主性细胞死亡,广泛参与肿瘤发生、发展和临床预后等多种重要的病理学过程。亚甲基四氢叶酸脱氢酶2(methylenetetrahydrofolata dehydrogenase 2,MTHFD2)作为一碳代谢的关键酶之一,在多种肿瘤细胞中高表达。在本研究中,为了探究MTHFD2对heCICs形成能力的影响,首先应用活细胞染料对肝癌细胞和免疫细胞分别进行标记,利用荧光显微镜对细胞进行拍摄分析建立heCICs模型。进一步通过RNAi技术瞬时敲低细胞中的MTHFD 2,结果显示,MTHFD 2敲低后,PLC/PRF/5和Hep3B分别与免疫细胞形成heCICs的能力显著升高(均P<0.01)。通过同源重组方法构建MTHFD2重组表达质粒,进一步构建MTHFD2过表达细胞系;将过表达细胞系与免疫细胞共培养检测MTHFD2过表达对heCICs形成能力的影响,结果显示,过表达MTHFD2后heCICs形成率显著降低(均P<0.001)。综上,本研究表明,MTHFD2是heCICs形成的负调控因子,为靶向MTHFD2促进heCICs形成增强免疫细胞胞内杀伤提供了研究基础。

Heterotypic cell-in-cell structures(heCICs)mediate unique non-autonomous cell death,which are widely involved in a variety of important pathological processes,such as tumorigenesis,progression and clinical prognosis.Methylenetetrahydrofolata dehydrogenase 2(MTHFD2),one of the key enzymes of one-carbon metabolism,is highly expressed in a variety of tumor cells.In this study,in order to investigate the effect of MTHFD2 on the formation of heCICs,liver cancer cells and immune cells were first labeled separately by live cell dyes,and the heCIC model was established by using fluorescence microscopy for cell imaging and analysis.After transiently knocking down MTHFD 2 in cells by RNAi,we found that the ability of PLC/PRF/5 and Hep3B to form heCICs with immune cells was significantly increased(all P<0.01).MTHFD2 recombinant expression plasmid was constructed by the homologous recombination method,and MTHFD2 overexpression cell lines were further constructed.Then,the effect of MTHFD2 overexpression on the ability to form heCICs was detected by co-culturing the overexpression cell lines with immune cells.The results showed that the rate of heCIC formation was significantly reduced after overexpression of MTHFD2(all P<0.001).In conclusion,this study demonstrated that MTHFD2 is a negative regulator of heCIC formation,providing a research basis for targeting MTHFD2 to promote heCIC formation and enhance the in-cell killing of immune cells.