BarH-like homeobox 2 represses the transcription of keratin 16 and affects Ras signaling pathway to suppress nasopharyngeal carcinoma progression

Restoring BARX2 in OSCC reverses partial EMT and suppresses metastasis through miR-186-5p/miR-378a-3p-dependent SERPINE2 inhibition

Tumor cells undergoing partial epithelial-mesenchymal transition (pEMT) are pivotal in local invasion and lymphatic metastasis of oral squamous cell carcinoma (OSCC), yet the mechanisms behind pEMT reversal remain poorly understood. In this study, the loss of BARX2 expression was revealed during the process of oral epithelial carcinogenesis and identified to activate the pEMT program, facilitate metastasis, and be associated with poor prognosis. Restoring BARX2 expression in OSCC cell lines effectively reversed tumor pEMT, evident in E/N-Cadherin switching, reduced cell invasion, proliferation, and stemness, and inhibited murine lung metastasis. BARX2 re-expression negatively correlated with several pEMT markers, notably SERPINE2, which was enriched in the invasive OSCC front, enhancing stemness and promoting metastasis, particularly in cervical lymph nodes. Furthermore, rescuing SERPINE2 impaired the inhibitory effect of BARX2 on the pEMT programs and reconstructed ECM through re-expression of MMP1. Mechanistically, we identified that BARX2 inhibited SERPINE2 through activating miR-186-5p and miR-378a-3p. These miRNAs, upregulated by BARX2, post-transcriptionally degraded SERPINE2 mRNA via targeting specific sequences. Blocking miR-186-5p and miR-378a-3p effectively abolished the negative regulatory effect of BARX2 on SERPINE2. Overall, our findings highlight BARX2 as a partial EMT-reverser in OSCC, providing fresh therapeutic prospects for restoring BARX2 signaling to inhibit invasion and metastasis.

Pancancer analysis of oncogenic BARX2 identifying its prognostic value and immunological function in liver hepatocellular carcinoma

The transcription factor BarH-like homeobox 2 (BARX2), a member of the Bar-like homeobox gene family, is involved in cell proliferation, differentiation, immune responses and tumorigenesis. However, the potential role of BARX2 in the development of liver hepatocellular carcinoma (LIHC) remains unclear. Therefore, we aimed to study the biological role of BARX2 in hepatocellular carcinoma. Through the UALCAN, GTEx PORTAL, TIMER 2.0, LinkedOmics, SMART, MethSurv, Metascape, GSEA and STRING public databases, the BARX2 mRNA level, prognostic value, coexpressed genes, associated differentially expressed genes, DNA methylation and functional enrichment of LIHC patients were studied. The relationships between BARX2 expression and various clinical or genetic parameters of LIHC patients were determined using data from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and BEAT LIHC databases. In addition, the biological function of BARX2 in LIHC was studied in vitro. Through large-scale data mining, our study showed that BARX2 was differentially expressed between different normal and tumour tissues.BARX2 expression in LIHC tissues was significantly lower than that in corresponding controls, especially in patients with T2-4 stage disease. In patients with LIHC, overexpression of BARX2 was an independent poor prognostic factor associated with poor cytogenetic risk and gene mutations. Genomic hypermethylation of the BARX2 gene was associated with upregulated BARX2 expression and poor overall survival (OS) in LIHC. Functional enrichment analysis showed that BARX2 had an immunomodulatory role and was involved in the inflammatory response in LIHC occurrence. In conclusion, the oncogene BARX2 may serve as a new biomarker and prognostic factor for patients with LIHC. The immunomodulatory function of BARX2 deserves further validation in LIHC.

A Kaleidoscope of Keratin Gene Expression and the Mosaic of Its Regulatory Mechanisms

Keratins are a family of intermediate filament-forming proteins highly specific to epithelial cells. A combination of expressed keratin genes is a defining property of the epithelium belonging to a certain type, organ/tissue, cell differentiation potential, and at normal or pathological conditions. In a variety of processes such as differentiation and maturation, as well as during acute or chronic injury and malignant transformation, keratin expression undergoes switching: an initial keratin profile changes accordingly to changed cell functions and location within a tissue as well as other parameters of cellular phenotype and physiology. Tight control of keratin expression implies the presence of complex regulatory landscapes within the keratin gene loci. Here, we highlight patterns of keratin expression in different biological conditions and summarize disparate data on mechanisms controlling keratin expression at the level of genomic regulatory elements, transcription factors (TFs), and chromatin spatial structure.

Molecular mechanism of FBXW7-mediated ubiquitination modification in nasopharyngeal carcinoma cell proliferation in vitro and in vivo

OBJECTIVES

Nasopharyngeal carcinoma (NPC) is a type of keratinizing squamous cell malignancy. Ubiquitination, a common protein posttranslational modification, participates in cancer development. This study sought to investigate the mechanism of F-box and WD repeat domain containing 7 (FBXW7) in NPC cell proliferation in vivo and in vitro.

METHODS

FBXW7, Homeobox A10 (HOXA10), and bone morphogenetic protein-2 (BMP2) expression levels in NPC tissues and cells were detected by RT-qPCR and Western blotting. Cell proliferation was assessed by cell counting kit-8 and colony formation assays. The binding of FBXW7 to HOXA10 and HOXA10 ubiquitination level were detected via co-immunoprecipitation and ubiquitination assay. Cells were treated with MG132 (the proteasome inhibitor), followed by the determination of HOXA10 ubiquitination and protein levels. The binding of HOXA10 to BMP2 was testified via dual-luciferase and chromatin immunoprecipitation assays. Collaborative experiments were performed to confirm the role of HOXA10 or BMP2 in FBXW7-mediated NPC cell proliferation. Xenograft tumor assay was performed to confirm the role of FBXW7/HOXA10/BMP2 in vivo.

RESULTS

FBXW7 was under-expressed, while HOXA10 and BMP2 were up-expressed in NPC tissues and cells. FBXW7 overexpression restricted NPC cell proliferation. Mechanically, FBXW7 bound to HOXA10 to promote ubiquitination-based degradation of HOXA10 and further reduced the binding of HOXA10 to the BMP2 promoter and inhibited BMP2 transcription. Overexpression of HOXA10 or BMP2 attenuated the role of FBXW7 overexpression in inhibiting NPC cell proliferation. FBXW7 overexpression reduced Ki67 positive rate and repressed tumor growth.

CONCLUSION

FBXW7 overexpression promoted HOXA10 ubiquitination-based degradation and further inhibited BMP2 transcription, consequently restricting NPC cell proliferation in vitro and in vivo.