[摘 要] 目的：探究β-1, 4-半乳糖基转移酶2（B4GALT2）对人乳腺癌MCF-7、MDA-MB-231细胞增殖、迁移和侵袭能力的影 响及其作用机制。方法： 用TCGA数据库和CPTAC蛋白组学数据库数据分析B4GALT2 mRNA和蛋白在乳腺癌组织中的表达， 并用免疫组织化学法检测中国人乳腺癌组织中B4GALT2蛋白的表达加以验证。采用Kaplan-Meier Plotter数据库数据分析乳腺 癌组织中 B4GALT2 mRNA 表达水平与患者预后的相关性。常规培养MCF-7、MDA-MB-231细胞，用转染试剂将 siNC、siRNA#1、 siRNA#2、空载体和 B4GALT2 过表达载体转染至 MCF-7、MDA-MB-231 细胞中，分为 NC 、siRNA#1 、siRNA#2 、空 载体和 OE-B4GALT2组。用CCK-8法、克隆形成实验检测敲减B4GALT2对MCF-7、MDA-MB-231细胞增殖能力的影响，划痕愈合实验 和 Transwell 小室实验检测敲减 B4GALT2 对 MCF-7、MDA-MB-231 细胞迁移及侵袭能力的影响。WB 法检测敲减或过表达 B4GALT2对MCF-7、MDA-MB-231细胞中PI3K/AKT信号通路磷酸化水平的影响。结果：在乳腺癌组织中B4GALT2 mRNA和 蛋白质均呈高表达（P < 0.01），B4GALT2 蛋白在中国人乳腺癌组织中也呈高表达（P < 0.000 1），进一步验证了上述结果。 B4GALT2高表达与患者总生存期（OS）、无复发生存期（PFS）和进展后生存期（PPS）缩短明显相关（P < 0.01，P < 0.05，P < 0.001）。 敲减B4GALT2表达后MCF-7、MDA-MB-231细胞的增殖、迁移及侵袭能力被明显抑制（均P < 0.01），PI3K/AKT信号通路被明显 抑制（均P < 0.01）；过表达B4GALT2后PI3K/AKT信号通路被明显激活（均P < 0.01）。结论： B4GALT2在乳腺癌组织中呈高表 达，其可通过调控PI3K/AKT信号通路促进MCF-7、MDA-MB-231细胞的恶性生物学行为。

[Abstract] Objective: To investigate the effects of β -1, 4-galactosyltransferase 2 (B4GALT2) on the proliferation, migration and invasion of human breast cancer MCF-7 and MDA-MB-231 cells, and to explore its underlying mechanism. Methods: The mRNA and protein expression of B4GALT2 in breast cancer tissues was analyzed using data from TCGA database and the CPTAC proteomics database. Immunohistochemical staining was used to validate the expression of B4GALT2 protein in breast cancer tissues of Chinese population. The correlation between B4GALT2 mRNA expression in breast cancer tissues and patient prognosis was analyzed using data from the Kaplan-Meier Plotter database. MCF-7 and MDA-MB-231 cells were routinely cultured and transfected with siNC, siRNA#1, siRNA#2, empty vector, and B4GALT2 overexpression plasmids using transfection reagents. The transfected cells were classified as NC group, siRNA#1 group, siRNA#2 group, empty vector group, and OE-B4GALT2 group accordingly. CCK-8 assay and clone formation assay were used to detect the effects of B4GALT2 knockdown on proliferation of transfected cells. Scratch healing assay and Transwell chamber assay were applied to evaluate the effects of B4GALT2 knockdown on cell migration and invasion. WB assay was used to detect the phosphorylation levels of the PI3K/AKT signaling pathway in MCF-7, MDA-MB-231 cells after B4GALT2 knockdown or overexpression. Results: B4GALT2 was highly expressed in breast cancer tissues at both mRNA and protein levels (both P < 0.01), and B4GALT2 protein was also highly expressed in Chinese breast cancer tissues (P < 0.000 1), confirming the initial findings. High B4GALT2 expression was significantly associated with shorter overall prognosis (OS), recurrence-free survival (RFS), and post-progression survival (PPS) (P < 0.01, P < 0.05, P < 0.001) in patients. After B4GALT2 knockdown, the proliferation, migration and invasion of MCF-7 and MDA-MB-231 cells were significantly suppressed (all P < 0.01), and the PI3K/AKT signaling pathway was significantly inhibited (all P < 0.01). The PI3K/AKT signaling pathway was significantly activated after B4GALT2 overexpression (all P < 0.01). Conclusion: B4GALT2 is highly expressed in breast cancer tissues. It promotes the malignant biological behaviors of MCF-7 and MDA-MB-231 cells by regulating the PI3K/AKT signaling pathway.

国家自然科学基金（No. 82071789）