Expression and functional study of MNX1 in breast cancer / 国际外科学杂志

ABSTRACT

Objective:Our study investigates the expression of Motor neuron and pancreatic homeobox 1 ( MNX1) in breast cancer tissues, and the effects of MNX1 on the proliferation, cell cycle, apoptosis, migration and invasion of MDA-MB-231 cells were studied by constructing the MNX1 knockdown MDA-MB-231 cell line. 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 MNX1 in tissues and cells. Western blot detects the protein level of MNX1 in the tissue. We designed the shRNA MNX1 and constructed the MNX1 viral vector with low expression. The viral vector was further used to infect triple-negative breast cancer cells. The MNX1 with the best silencing effect was designed to silence the breast cancer cell line MDA-MB-231 as the silence group ( 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 ( Mean± SD). The t-test was used for the comparison of two sample means. Results:The qRT-PCR showed that the expression level of MNX1 mRNA in breast cancer tissue was higher than that in adjacent tissues ( P<0.05). WB showed that the expression level of MNX1 protein in breast cancer tissue was significantly higher than that in adjacent tissues ( 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 ( P<0.05). The results showed that silencing the 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 ( 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 ( P<0.05). Our results show that silencing the 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 ( P<0.05). MNX1 promotes the apoptosis of triple-negative breast cancer cells. Conclusion:MNX1 is a new breast cancer gene, silencing the expression of 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.