目的:研究运动神经元和胰腺同源盒1(n MNX1)在乳腺癌组织中的表达，通过构建n MNX1沉默的MDA-MB-231细胞株，检测n MNX1对乳腺癌细胞增殖、凋亡、迁移和侵袭等生物学功能的作用。n 方法:收集广西医科大学第一附属医院乳腺癌73例患者的73对乳腺癌组织和邻近正常组织进行回顾性研究，采用qRT-PCR检测n MNX1在组织和细胞中的相对表达，使用Western blotting检测组织中n MNX1的蛋白质水平。我们设计了n MNX1的n shRNA，构建了低表达的n MNX1病毒载体。病毒载体进一步用于感染三阴性乳腺癌细胞。设计沉默效果最好的n MNX1靶向沉默乳腺癌细胞株MDAMB-231作为沉默组(n shMNX1)，设计空载体慢病毒感染的阴性对照组(Control)以进行后续的细胞功能实验。采用CCK-8实验检测细胞增殖能力，Transwell实验检测细胞迁移和侵袭能力，用流式细胞仪检测细胞凋亡，每个实验至少有3次独立实验，正态分布的计量资料以均数±标准差(n Mean±n SD)表示，组间比较采用n t检验。n 结果:qRT-PCR结果显示，在乳腺癌组织中n MNX1基因的表达水平高于癌旁组织(n P<0.05)。Western blotting显示乳腺癌组织中n MNX1基因的蛋白表达水平明显高于邻近组织(n P<0.01)。CCK-8实验结果显示，沉默组乳腺癌细胞在24、48和72 h的外径(450 nm)低于阴性对照组(n P<0.05)，可以认为沉默n MNX1基因可抑制乳腺癌细胞的增殖。Transwell结果显示，迁移实验中，沉默组和阴性对照组通过跨室的细胞数分别为217.00±33.23和490.00±45.56；侵袭实验中，沉默组和阴性对照组通过跨室的细胞数分别为91.00±12.79和419.00±49.37，可以认为沉默n MNX1基因可以抑制乳腺癌细胞株MDA-MB-231的迁移和侵袭能力。在流式细胞术检测细胞凋亡中，沉默组乳腺癌细胞凋亡率为(3.81±0.41)%，阴性对照组为(2.13±0.16)%。沉默组乳腺癌细胞凋亡率高于阴性对照组，说明沉默n MNX1基因促进乳腺癌细胞株MDA-MB-231的的凋亡。n 结论:MNX1在乳腺癌组织中高表达，沉默n MNX1基因的表达抑制乳腺癌细胞的增殖、迁移和侵袭，促进细胞凋亡。n “,”Objective:Our study investigates the expression of Motor neuron and pancreatic homeobox 1 (n MNX1) in breast cancer tissues, and the effects of n MNX1 on the proliferation, cell cycle, apoptosis, migration and invasion of MDA-MB-231 cells were studied by constructing the n MNX1 knockdown MDA-MB-231 cell line.n Methods:A retrospective study was conducted on 73 breast cancer tissues and adjacent normal tissues from 73 breast cancer patients in the First Affiliated Hospital of Guangxi Medical University. qRT-PCR was used to detect the relative expression of n MNX1 in tissues and cells. Western blot detects the protein level of n MNX1 in the tissue. We designed the n shRNA MNX1 and constructed the n MNX1 viral vector with low expression. The viral vector was further used to infect triple-negative breast cancer cells. The n MNX1 with the best silencing effect was designed to silence the breast cancer cell line MDA-MB-231 as the silence group (n shMNX1), and the negative control group (Control) of lentivirus infection was designed to carry out follow-up cell function tests.CCK-8 method was used to detect cell proliferation ability. Transwell method was used to detect cell migration and invasion ability. Use flow cytometry to detect apoptosis. Each experiments at least 3 times independent experiments and measurement data with normal distribution were represented as the (n Mean±n SD). The n t-test was used for the comparison of two sample means.n Results:The qRT-PCR showed that the expression level of n MNX1 mRNA in breast cancer tissue was higher than that in adjacent tissues (n P<0.05). WB showed that the expression level ofn MNX1 protein in breast cancer tissue was significantly higher than that in adjacent tissues (n P<0.01) . CCK-8 experiment results showed that the OD (450 nm) of breast cancer cells in the silence group at 24, 48 and 72 h was lower than that of the negative control group (n P<0.05). The results showed that silencing then MNX1 gene can inhibit the proliferation of breast cancer cells MDA-MB-231. The results of Transwell migration experiment showed that the number of cells passing through the Transwell chamber in the silent group and the negative control group were 217.00±33.23 and 490.00±45.56, respectively, and the difference was significant (n P<0.05). The results of Transwell invasion experiment showed that the number of cells in the silent group and the negative control group passing through the Transwell chamber were (91.00±12.79)and (419.00±49.37), respectively, and the difference was statistically significant (n P<0.05). Our results show that silencing then MNX1 gene can inhibit the migration and invasion ability of breast cancer cell line MDA-MB-231. The results showed that the apoptosis rate of breast cancer cells in the silent group was (3.81±0.41)%, and the negative control group was (2.13±0.16)%. The apoptosis rate of breast cancer cells in the silent group was higher than that in the negative control group, and the result was statistically significant (n P<0.05).n MNX1 promotes the apoptosis of triple-negative breast cancer cells.n Conclusion:MNX1 is a new breast cancer gene, silencing the expression of n MNX1 gene inhibits the proliferation, migration and invasion of breast cancer cells and promotes cell apoptosis, which provides a new regulatory mechanism and therapeutic target for breast cancer.n