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

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.

Spectrum of MNX1 Pathogenic Variants and Associated Clinical Features in Korean Patients with Currarino Syndrome

BACKGROUND: The major genetic cause of Currarino syndrome (CS), a congenital malformation syndrome typically characterized by sacral agenesis, anorectal malformation, and presence of a pre-sacral mass, is known to be pathogenic variants in motor neuron and pancreas homeobox 1 (MNX1), which exist in almost all familial cases and 30% of sporadic cases. Less commonly, a large deletion or a complex rearrangement involving the 7q36 region is associated with CS. We investigated the spectrum of MNX1 pathogenic variants and associated clinical features in the Korean patients with CS. METHODS: We enrolled 25 patients with CS, including 24 sporadic cases and one familial case. Direct sequencing of MNX1 and multiplex ligation-dependent probe amplification were performed. We also analyzed clinical phenotypes and evaluated genotype-phenotype correlations. RESULTS: We identified six novel variants amongst a total of six null variants, one missense variant, and one large deletion. The null variants included four frameshift variants (p.Gly98Alafs*124, p.Gly145Alafs*77, p.Gly151Leufs*67, and p.Ala216Profs*5) and two nonsense variants (p.Tyr186* and p.Gln212*). The missense variant, p.Lys295Gln, was located in the highly-conserved homeobox domain and was predicted to be deleterious. A large deletion involving the 7q36 region was detected in one patient. Pathogenic variants in MNX1 were detected in 28% of all CS cases and 25% of sporadic cases. The clinical phenotype was variable in patients with and without pathogenic variants; no significant genotype-phenotype correlation was observed. CONCLUSIONS: This study revealed the spectrum and phenotypic variability of MNX1 pathogenic variants in the Korean population.

Currarino triad with Mullerian duct anomaly in mother and daughter without MNX1 gene mutation

The Currarino triad is a unique complex of congenital caudal anomalies, including anorectal malformation, sacral bony defect and presacral mass. This triad may be associated with Mullerian duct anomalies, such as duplication of the vagina and uterus. Each of these diseases has a familial tendency and sometimes coexist within families. But, when coexisting in familial cases, nearly all reported cases revealed mutations of the motor neuron and pancreas homeobox 1 (MNX1) gene. Familial cases of Currarino triad combined with Mullerian duct anomaly without MNX1 gene mutation are very rare. Here we report cases of mother and daughter, who had Currarino triad and Mullerian duct anomaly without MNX1 gene mutation, along with a brief literature review.