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Background: BRD7 is a tumor suppressor known to inhibit cell proliferation and cell cycle progression and initiate apoptosis in breast cancer. However, the function and underlying molecular events of BRD7 in tumor invasion and metastasis in breast cancer are not fully understood.Methods: BRD7 expression was assessed in two stable cell lines MDA231 and MCF7 with BRD7 overexpression and one stable cell line MDA231 with BRD7 interference using qRT-PCR and western blotting. CCK8 assay was used to examine the proliferation ability of MDA231 and MCF7 cells. Scratch wound healing assay was used to evaluate cell migration in MDA231 and MCF7 cells. Both Matrigel and three-dimensional invasion assays were performed to investigate the cell invasion ability after BRD7 overexpression or silencing or YB1 restoration in MDA231 and MCF7 cells. The potential interacting proteins of BRD7 were screened using co-immunoprecipitation combined with mass spectrometry and verified by co-immunoprecipitation in HEK293T cells. Additionally, we confirmed the specific binding region between BRD7 and YB1 in HEK293T cells by constructing a series of deletion mutants of BRD7 and YB1 respectively. Finally, xenograft and metastatic mouse models using MDA231 cells were established to confirm the effect of BRD7 on tumor growth and metastasis.Results: Here, the results of a series of assays in vitro indicated that BRD7 has the ability to inhibit the mobility, migration and invasion of breast cancer cells. In addition, YB1 was identified as a novel interacting protein of BRD7, and BRD7 was found to associate with the C-terminus of YB1 via its N-terminus. BRD7 decreases the expression of YB1 through negatively regulating YB1 phosphorylation at Ser102, thereby promoting its proteasomal degradation. Furthermore, gene set enrichment analysis revealed that epithelial-mesenchymal transition (EMT) is the common change occurring with altered expression of either BRD7 or YB1 and that BRD7 represses mesenchymal genes and activates epithelial genes. Moreover, restoring the expression of YB1 antagonized the inhibitory effect of BRD7 on tumorigenicity, EMT, invasiveness and metastasis through a series of in vitro and in vivo experiments. Additionally, BRD7 expression was negatively correlated with the level of YB1 in breast cancer patients. The combination of low BRD7 and high YB1 expression was significantly associated with poor prognosis, distant metastasis and advanced TNM stage.

BRD7 functions as a crucial tumor suppressor in numerous malignancies. However, the effects of BRD7 on colorectal cancer (CRC) progression are still unknown. Here, based on the BRD7 knockout (BRD7–/–) and BRD7flox/flox (BRD7+/+) mouse models constructed in our previous work, we established an azoxymethane/dextran sodium sulfate (AOM/DSS)-induced mouse model. BRD7+/+ mice were found to be highly susceptible to AOM/DSS-induced colitis-associated CRC, and BRD7 significantly promoted cell proliferation and cell cycle G1/S transition but showed no significant effect on cell apoptosis. Furthermore, BRD7 interacted with c-Myc and stabilized c-Myc by inhibiting its ubiquitin–proteasome-dependent degradation. Moreover, restoring the expression of c-Myc in BRD7-silenced CRC cells restored cell proliferation, cell cycle progression, and tumor growth in vitro and in vivo. In addition, BRD7 and c-Myc were both significantly upregulated in CRC patients, and high expression of these proteins was associated with clinical stage and poor prognosis in CRC patients. Collectively, BRD7 functions as an oncogene and promotes CRC progression by regulating the ubiquitin–proteasome-dependent stabilization of c-Myc protein. Targeting the BRD7/c-Myc axis could be a potential therapeutic strategy for CRC.

Edited by Xiao-Fan WangYin Yang 1 (YY1) is a zinc-finger protein that plays critical roles in various biological processes by interacting with DNA and numerous protein partners. YY1 has been reported to play dual biological functions as either an oncogene or tumor suppressor in the development and progression of multiple cancers, but its role in human nasopharyngeal carcinoma (NPC) has not yet been revealed. In this study, we found that YY1 overexpression significantly inhibits cell proliferation and cell-cycle progression from G 1 to S and promotes apoptosis in NPC cells. Moreover, we identified YY1 as a component of the c-Myc complex and observed that ectopic expression of YY1 inhibits c-Myc transcriptional activity, as well as the promoter activity and expression of the c-Myc target gene microRNA-141 (miR-141). Furthermore, restoring miR-141 expression could at least partially reverse the inhibitory effect of YY1 on cell proliferation and tumor growth and on the expression of some critical c-Myc targets, such as PTEN/AKT pathway components both in vitro and in vivo.We also found that YY1 expression is reduced in NPC tissues, negatively correlates with miR-141 expression and clinical stages in NPC patients, and positively correlates with survival prognosis. Our results reveal a previously unappreciated mechanism in which the YY1/c-Myc/miR-141 axis plays a critical role in NPC progression and may provide some potential and valuable targets for the diagnosis and treatment of NPC.

ObjectivesTo explore the risk factors related to regional lymph node metastasis in cervical cancer and analyze the value of independent risk factors in predicting regional lymph node metastasis.MethodsWe retrospectively analyzed the clinical data of 699 patients who underwent surgery for stage IB1–IIA2 cervical cancer in Quanzhou First Hospital affiliated to Fujian Medical University from 2010 to 2016. The patients were divided into metastasis (n = 92) and non-metastasis (n = 607) groups based on the postoperative pathology of regional lymph node status. The relevant clinicopathological features of the metastasis and non-metastasis groups were compared through variance analysis and chi-square tests. Logistic regression was adopted to screen relevant independent risk factors of regional lymph node metastasis.ResultsIn univariate analysis, International Federation of Gynecology and Obstetrics (FIGO) stages, serum squamous cell carcinoma antigen (SCC-Ag), histological type of squamous carcinoma and maximal tumor diameter were related factors for lymphatic metastasis in patients with cervical cancer. In multivariate analysis, SCC-Ag and histological type of squamous carcinoma were independent prognostic factors for lymphatic metastasis in patients with cervical cancer. Pre-treatment SCC-Ag serum levels, as a predictor of lymph node metastasis of cervical cancer, revealed a sensitivity of 62.07% (95% confidence interval (CI): 51.03–72.62%), specificity of 65.15% (59.07–70.89%), and area under the receiver operating characteristic (ROC) curve of 0.69 (95% CI: 0.61–0.76).ConclusionsCervical cancer patients whose pathological type is squamous carcinoma with high levels of SSC-Ag pre-operation are more likely to be diagnosed with regional lymph node metastasis. Standardized lymph node dissection should be implemented during operation.

Hot Deformation Behavior and Constitutive Model of the nickel-base alloy Nimonic Alloy as–forged are investigated by hot compression tests in the ranges of strain rate (0.001-1s−1) and temperature 1323-1423K, at intervals 50K. During the process of compression deformation, with the increase of true strain, the flow stress first increases rapidly to the peak value. Then, the flow stress decreases with the increase of true strain. Flow curves show dynamic recrystallization occurs at low strain rate (0.001-0.1 s−1) and temperature (1323-1423K). The softening mechanism at high strain rate (1 s−1) is dynamic recovery. According to the values of the ture stress and strain, the material constants of constitutive model are calculated and Arrhenius-type equation is given.