Expression and clinical prognostic value of CYB561 in breast cancer

Role of the human cytochrome b561 family in iron metabolism and tumors (Review)

The human cytochrome b561 (hCytb561) family consists of electron transfer transmembrane proteins characterized by six conserved α-helical transmembrane domains and two β-type heme cofactors. These proteins contribute to the regulation of iron metabolism and numerous different physiological and pathological processes by recycling ascorbic acid and maintaining iron reductase activity. Key members of this family include cytochrome b561 (CYB561), duodenal CYB561 (Dcytb), lysosomal CYB561 (LCytb), stromal cell-derived receptor 2 (SDR2) and 101F6, which are widely expressed in human tissues and participate in the pathogenesis of several diseases and tumors. They are associated with the promotion or inhibition of tumor growth and progression in various malignancies and are potential therapeutic targets for malignant tumors. The present review summarizes the existing literature regarding the structure of the Cytb561 family, the basic functional characteristics of hCytb561 family members, and the roles of the CYB561, Dcytb, LCytb, SDR2 and 101F6 in various diseases and tumors.

ITGB4/GNB5 axis promotes M2 macrophage reprogramming in NSCLC metastasis

OBJECTIVE

Metastasis of non-small cell lung cancer (NSCLC) is a leading cause of high mortality. In recent years, the role of M2 macrophages in promoting tumor metastasis within the tumor microenvironment has garnered increasing attention. This study aims to investigate the role and potential mechanisms of the ITGB4/GNB5 axis in regulating M2 macrophage reprogramming and influencing NSCLC metastasis.

METHODS

This study first used single-cell sequencing technology to reveal the diverse subpopulation structure of NSCLC tumor tissues. Data analysis then identified the correlation between M2 macrophages and the malignant phenotype of NSCLC. Flow cytometry and immunohistochemistry were used to detect changes in M2 macrophages in NSCLC tissues. The impact of the ITGB4/GNB5 axis on M2 macrophage function was assessed through RNA sequencing and proteomic analysis. Finally, in vitro cell experiments and in vivo mouse models were used to validate the function and regulatory mechanisms of this axis.

RESULTS

Our study found diverse cellular subpopulations in NSCLC tumor tissues, with M2 macrophages closely associated with the malignant phenotype of NSCLC. We identified ITGB4 as a characteristic gene of NSCLC and predicted GNB5 as an interacting gene through database analysis. Activation of the ITGB4/GNB5 axis was shown to enhance M2 macrophage polarization, promoting their accumulation in the tumor microenvironment. This change further facilitated NSCLC invasion and metastasis by modulating related cytokines and signaling pathways. Animal experiments demonstrated that inhibition of the ITGB4/GNB5 axis significantly reduced tumor growth and metastasis.

CONCLUSION

The ITGB4/GNB5 axis reshapes the TME by promoting M2 macrophage polarization and functional enhancement, thereby facilitating tumor invasion and metastasis in NSCLC. This research provides new insights into the molecular mechanisms of NSCLC and offers potential molecular targets for future targeted therapies.

CYB561 is a potential therapeutic target for breast cancer and is associated with immune cell infiltration

BACKGROUND

Breast cancer (BC), a common malignant tumor originating from the terminal ductal lobular unit of the breast, poses a substantial health risk to women. Previous studies have associated cytochrome b561 (CYB561) with a poor prognosis in BC; however, its underlying mechanism of this association remains unclear.

METHODS

We investigated the expression of CYB561 mRNA in BC using databases such as The Cancer Genome Atlas, Gene Expression Omnibus, Tumor-Normal-Metastatic plot, and Kaplan-Meier plotter databases. The prognostic value of CYB561 protein in BC was assessed in relation to its expression levels in tumor tissue samples from 158 patients with BC. The effect of CYB561 on BC progression was confirmed using in vivo and in vitro experiments. The biological functions and related signaling pathways of CYB561 in BC were explored using gene microarray, Innovative Pathway, Gene Ontology enrichment, and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. The correlation between CYB561 and the BC tumor immune microenvironment was evaluated using the CIBERSORT algorithm and single-cell analysis and further validated through immunohistochemistry of serial sections.

RESULTS

Our study demonstrated that upregulation of CYB561 expression predicted poor prognosis in patients with BC and that CYB561 knockdown inhibited the proliferation, migration, and invasive ability of BC cells in vitro. CYB561 knockdown inhibited BC tumor formation in vivo.CYB561 was observed to modulate downstream tropomyosin 1 expression. Furthermore, CYB561 expression was associated with macrophage M2 polarization in the BC immune microenvironment.

CONCLUSIONS

Elevated CYB561 expression suggests a poor prognosis for patients with BC and is associated with macrophage M2 polarization in the BC microenvironment. Therefore, CYB561 could potentially serve as a therapeutic target for BC treatment.

CYB561 promotes HER2+ breast cancer proliferation by inhibiting H2AFY degradation

Breast cancer (BRCA) has a high incidence and mortality rate among women. Different molecular subtypes of breast cancer have different prognoses and require personalized therapies. It is imperative to find novel therapeutic targets for different molecular subtypes of BRCA. Here, we demonstrated for the first time that Cytochromeb561 (CYB561) is highly expressed in BRCA and correlates with poor prognosis, especially in HER2-positive BRCA. Overexpression of CYB561 could upregulate macroH2A (H2AFY) expression in HER2-positive BRCA cells through inhibition of H2AFY ubiquitination, and high expression of CYB561 in HER2-positive BRCA cells could promote the proliferation and migration of cells. Furthermore, we have demonstrated that CYB561 regulates H2AFY expression, thereby influencing the expression of NF-κB, a downstream molecule of H2AFY. These findings have been validated through in vivo experiments. In conclusion, we propose that CYB561 may represent a novel therapeutic target for the treatment of HER2-positive BRCA. Graphical abstract CYB561 promotes the proliferation of HER2+ BRCA cells: CYB561 enhances the expression of H2AFY by inhibiting its ubiquitination, which leads to an increase expression of NF-κB in the nucleus. H2AFY, together with NF-κB, promotes the proliferation of HER2+ BRCA cells.

Cytochrome b561 regulates iron metabolism by activating the Akt/mTOR pathway to promote Breast Cancer Cells proliferation

Breast cancer (BC) is the leading cause of cancer-related mortality in women, necessitating the development of novel therapeutic targets. While cytochrome b561 (CYB561) expression is associated with poor prognosis in BC, the precise role of CYB561 in BC and its potential mechanisms remain unclear. In the present study, we found that CYB561 plays an essential role in BC growth. CYB561 expression was up-regulated in surgically resected cancerous tissues and in six BC cell lines. Lentivirus-mediated CYB561 knockdown in BC cells significantly reduced their proliferation, migration, and invasiveness. CYB561 participates in the regulation of iron metabolism in BC. CYB561 knockdown reduced total iron content, increased ferrous iron content, and down-regulated the expression of proteins associated with iron metabolism (transferrin receptor 1, divalent metal transporter 1, and ferritin heavy chain 1). Conversely, up-regulation of CYB561 through co-incubation with exogenous iron (ferric ammonium citrate) produced contrary outcomes. Additionally, CYB561 activated the protein kinase B/mammalian target of rapamycin (Akt/mTOR) signaling pathway in BC cells. Down-regulation of CYB561 expression inhibited the Akt/mTOR signaling pathway activity. The application of an mTOR agonist (MHY1485) rescued this negative effect, as well as the inhibitory effect of CYB561 knockdown on cell proliferation. Importantly, the dual mTOR inhibitor MLN0128 (50 nM, 48 h) down-regulated CYB561 expression and the iron metabolism-related proteins transferrin receptor, divalent metal transporter 1, and ferritin heavy chain 1, whereas the mTOR agonist MHY1485 rescued the down-regulation of CYB561 knockdown on iron metabolism-related proteins. We conclude that CYB561 promotes the proliferation of BC cells by regulating iron metabolism through the activation of the Akt/mTOR signaling pathway.

The Prognostic Value of lncRNA MCM3AP-AS1 on Clinical Outcomes in Various Cancers: A Meta- and Bioinformatics Analysis

Background. MCM3AP antisense RNA 1 (MCM3AP-AS1) is a newly identified potential tumor biomarker. Nevertheless, the prognostic value of MCM3AP-AS1 in cancer has been inconsistent in the available studies. We performed this meta-analysis to identify the prognostic role of MCM3AP-AS1 in various cancers. Methods. We searched PubMed, Web of Science, EMBASE, and the Cochrane Library databases to screen relevant studies. Hazard ratios (HR) or odds ratios (OR) and corresponding 95% confidence intervals (CI) were used to evaluate the relationship between aberrant MCM3AP-AS1 expression and survival and clinicopathological features (CFS) of cancer patients. A meta-analysis was performed using STATA 12.0 software. Additionally, results were validated by an online database based on The Cancer Genome Atlas (TCGA). Subsequently, we analyzed the MCM3AP-AS1-related genes and molecular mechanisms based on the MEM database. Results. Our results showed that overexpression of MCM3AP-AS1 was related to poor overall survival (OS) ( $\text{HR}=2.00$ , 95% CI, 1.52–2.64, $P<0.001$ ) and relapse-free survival (RFS) ( $\text{HR}=3.28$ , 95% CI 1.56–6.88, $P=0.002$ ). In addition, MCM3AP-AS1 overexpression was associated with TNM stage, differentiation grade, and lymph node metastasis, but not significantly with age, gender, and tumor size. In addition, MCM3AP-AS1 overexpression was verified by the GEPIA online database to be associated with poorer survival. The further functional investigation suggested that MCM3AP-AS1 may be involved in several cancer-related pathways. Conclusions. The overexpression of MCM3AP-AS1 was related to poor survival and CFS. MCM3AP-AS1 may be considered a novel prognostic marker and therapeutic target in various cancers.