目的:探究敲低NSD2基因对三阴性乳腺癌（triple negative breast cancer，TNBC）细胞基因表达谱及紫杉醇（paclitaxel，PTX）化疗敏感性的影响。 方法:利用慢病毒shRNA载体介导敲低MDA‑MB‑231细胞中NSD2基因，使用基因表达谱芯片筛选差异表达基因，进行聚类分析、GO和KEGG富集分析。采用Realtime PCR和Western blot检测NSD2的mRNA及蛋白表达水平，在PTX作用条件下，Hoechst染色观察细胞的凋亡形态特征，Annexin V‑FITC/PI法检测细胞的凋亡率，Western blot检测程序性细胞死亡通路相关差异基因的蛋白表达水平。利用TIMER2.0、UALCAN和Kaplan‑Meier Plotter数据库分析乳腺癌组织、TNBC组织和正常乳腺组织中NSD2、程序性细胞死亡通路相关差异基因的表达以及在接受过化疗的TNBC患者中的预后评估价值。 结果:基因芯片共筛选483个差异基因，包括324个上调基因和159个下调基因（P<0.01）；GO和KEGG富集分析发现差异表达基因与坏死性凋亡、凋亡等程序性细胞死亡信号通路显著相关（P<0.05）。敲低NSD2基因显著增加PTX作用下MDA‑MB‑231细胞的凋亡率，程序性细胞死亡相关蛋白TNFSF10、TNFRSF10B、FAS、CASP1以及Cleaved PARP1表达也明显增强（P<0.05）。与正常乳腺组织相比，乳腺癌和TNBC中NSD2和PARP1表达显著上调，而TNFSF10、FAS、CASP1表达均显著下调（P<0.001）；接受过化疗的TNBC患者中，NSD2高表达患者无复发生存率低于低表达患者，而TNFRSF10B、FAS、CASP1高表达患者预后优于低表达患者（P<0.05）。 结论:敲低NSD2改变TNBC细胞的基因表达谱，并通过诱导程序性死亡增强细胞对PTX化疗的敏感性，为寻找TNBC化疗耐药的分子靶标提供了新的见解。

Objective:To investigate the effects of NSD2 knockdown on gene expression profile and the chemosensitivity to paclitaxel （PTX） in triple negative breast cancer （TNBC） cells. Methods:Lentviral shRNA vector was used to mediate NSD2 gene knockdown in MDA‑MB‑231 cells. Gene expression microarrays were used to screen for differentially expressed genes and cluster analysis， GO and KEGG enrichment analysis were performed. Realtime PCR and Western blot were used to determine the amount of NSD2 mRNA and protein expression. Upon the treatment of PTX， the morphology of apoptotic cells was observed by Hoechst staining， and the apoptosis rate was assessed by Annexin V‑FITC/PI staining. Western blot analysis was performed to detect the protein expression levels of differential genes associated with programmed cell death pathway. TIMER2.0， UALCAN， and Kaplan‑Meier Plotter databases were used to analyze the expression of NSD2 and differential genes associated with programmed cell death pathway in breast cancer， TNBC， and normal breast tissues， as well as their prognostic value in TNBC patients who had received chemotherapy. Results:A total of 483 differentially expressed genes were screened by microarray， including 324 up‑regulated genes and 159 down‑regulated genes （P<0.01）. GO and KEGG enrichment analysis showed that differentially expressed genes were significantly involved in programmed cell death signaling pathways such as apoptosis and necroptosis （P<0.05）. Knockdown of NSD2 significantly increased the apoptosis rate of MDA‑MB‑231 cells upon PTX treatment， and the expression levels of proteins related to programmed cell death， including TNFSF10， TNFRSF10B， FAS， CASP1， and Cleaved PARP1， were also significantly enhanced （P<0.05）. Compared to normal breast tissues， the expression levels of NSD2 and PARP1 in breast cancer and TNBC were significantly up‑regulated， while the expression levels of TNFSF10， FAS and CASP1 were significantly down‑regulated （P<0.001）. Among TNBC patients who had received chemotherapy， the relapse‑free survival rate of patients with high NSD2 expression was lower than that of patients with low expression， whereas patients with high expression of TNFRSF10B， FAS， or CASP1 had a better prognosis than those with low expression （P<0.05）. Conclusion:Knockdown of NSD2 changes the gene expression profile of TNBC cells and increases the chemosensitivity to PTX by inducing programmed death， providing a novel insight into the molecular targets of chemotherapy resistance in TNBC.

R737.9

国家自然科学基金资助项目（82160582）；云南省科技厅基础研究计划面上项目（202201AT070003）；大理市科研基金资助项目（2021KBG036）；大理大学第一附属医院学科建设骨干项目（DFYGG2022?01）；大理大学第一附属医院临床医学研究中心项目（DFYXY009）