Hypermethylation of the ADIRF promoter regulates its expression level and is involved in NNK-induced malignant transformation of lung bronchial epithelial cells

E2F2(E2F transcription factor 2) as a potential therapeutic target in meibomian gland carcinoma: evidence from functional and epigenetic studies

BACKGROUND

Meibomian Gland Carcinoma (MGC) is a highly malignant eyelid tumor with a poor prognosis. This study investigates the molecular mechanisms underlying MGC, focusing on the abnormal expression of E2F transcription factor 2 (E2F2), often observed in tumors and potentially linked to DNA methylation.

METHODS

E2F2 expression was measured in MGC cells and tissues. Tissue samples from 3 normal meibomian glands (MG) and 36 MGC patients were used to construct a tissue microarray. Functional assays were performed by modifying E2F2 expression, including CCK8, wound healing, Transwell, and analysis of epithelial-mesenchymal transition (EMT)-related markers. Flow cytometry was used to assess cell apoptosis and cell cycle. RNA sequencing was conducted to identify differential genes after treating MGC cells with the methylation inhibitor 5-aza-2'-deoxycytidine (5-aza-2-dc), to explore the relationship between E2F2 downregulation in MGC and methylation.

RESULTS

E2F2 expression was significantly lower in MGC cells compared to normal MG cells. Immunohistochemical analysis showed low E2F2 expression in MGC. Specifically, immunohistochemical staining results have revealed a negative correlation trend between E2F2 and Ki-67 expression, as well as a positive correlation trend between E2F2 and P21, P27 expression. E2F2 knockdown increased MGC cell proliferation, migration, and invasion. Flow cytometry revealed that E2F2 knockdown reduced apoptosis, decreased the G0/G1 phase, and increased the S phase, while E2F2 overexpression produced opposite effects. RNA sequencing revealed that a total of 87 genes were differentially expressed in the 5-aza-2-dc experimental group compared to the control group, with 72 mRNAs showing upregulated expression and 15 mRNAs showing downregulated expression. Bioinformatics analysis results indicated that the functions of these differentially expressed genes were concentrated, and the biological processes mainly involved DNA replication, among others. The signaling pathways associated with these genes primarily included DNA replication and the cell cycle. RNA sequencing identified differential gene expression after methylation inhibition in MGC cells with 5-aza-2-dc, demonstrating that demethylation significantly upregulated E2F2. MSP assays confirmed reduced methylation levels. Additionally, inhibiting gene methylation in MGC cells suppressed proliferation, migration, and invasion.

CONCLUSION

E2F2 presents a promising therapeutic target for MGC. Overexpression of E2F2 and methylation inhibition in MGC cells may reverse E2F2 gene silencing, inhibiting malignant progression. These findings provide new perspectives for targeted therapies and precise, individualized treatment in MGC.

Effect of Seminal Plasma on the Freezability of Boar Sperm

BACKGROUND

Seminal plasma is an important component of semen and has a significant effect on sperm function. However, the relationship between seminal plasma and sperm freezing capacity has not been fully studied.

PURPOSE

Exploring metabolites and proteins related to the boar sperm freezing capacity in seminal plasma, by metabolomic and proteomic approaches, and directly verifying the protective effect of seminal plasma on the cryopreservation of boar sperm using high and low freezability seminal plasma as base freezing extender.

METHODS

Semen samples were collected from 30 different boars, 11 high and 11 low freezing-resistant boars were selected after freezing 2~4 times, and seminal plasma was selected at the same time. Sperm motility and movement parameters were analyzed using a CASA system. Reproductive hormones (Testosterone, progesterone, estradiol, prolactin, prostaglandin F2α, luteinoid hormone) in seminal plasma were detected by ELISA. Analysis of proteins and metabolites in high and low freezing-resistant seminal plasma by proteomics and metabolomics techniques.

RESULTS

The six reproductive hormones tested were not significantly associated with sperm freezing resistance. A total of 13 differentially expressed metabolites (DEMs) and 38 differentially expressed proteins (DEPs) were identified, while a total of 348 metabolites and 1000 proteins were identified. These DEMs were related to energy metabolism, drugs, or environmental pollutants, while the DEPs were mainly involved in the cytoskeletal dynamics and cell adhesion processes. There were 33 metabolites and 70 proteins significantly associated with mean progress motility (PM) at 10 min and 2 h after thawing. The 70 related proteins were associated with cell division and cycle regulation in gene ontology (GO) terms, as well as KEGG pathways, thermogeneration, and pyruvate metabolism. Using highly freezable boar SP as a base freezing extender made no difference from using lowly freezable boar SP, and both were not as good as the commercial control.

CONCLUSION

There were significant differences in seminal plasma with different freezability, but the similarity was much greater than the difference. The protection effect of seminal plasma is not remarkable, and it does not exhibit superior cryoprotective properties compared to commercial semen cryoelongators.

SIGNIFICANCE

This study provides a deeper understanding of how seminal plasma composition affects sperm freezabilty. It provides potential biomarkers and targets for improving sperm cryopreservation techniques.

TNFRSF19 within the 13q12.12 Risk Locus Functions as a Lung Cancer Suppressor by Binding Wnt3a to Inhibit Wnt/β-Catenin Signaling

Cancer risk loci provide special clues for uncovering pathogenesis of cancers. The TNFRSF19 gene located within the 13q12.12 lung cancer risk locus encodes TNF receptor superfamily member 19 (TNFRSF19) protein and has been proved to be a key target gene of a lung tissue-specific tumor suppressive enhancer, but its functional role in lung cancer pathogenesis remains to be elucidated. Here we showed that the TNFRSF19 gene could protect human bronchial epithelial Beas-2B cells from pulmonary carcinogen nicotine-derived nitrosamine ketone (NNK)-induced malignant transformation. Knockout of the TNFRSF19 significantly increased NNK-induced colony formation rate on soft agar. Moreover, TNFRSF19 expression was significantly reduced in lung cancer tissues and cell lines. Restoration of TNFRSF19 expression in A549 lung cancer cell line dramatically suppressed the tumor formation in xenograft mouse model. Interestingly, the TNFRSF19 protein that is an orphan membrane receptor could compete with LRP6 to bind Wnt3a, thereby inhibiting the Wnt/β-catenin signaling pathway that is required for NNK-induced malignant transformation as indicated by protein pulldown, site mutation, and fluorescence energy resonance transfer experiments. Knockout of the TNFRSF19 enhanced LRP6-Wnt3a interaction, promoting β-catenin nucleus translocation and the downstream target gene expression, and thus sensitized the cells to NNK carcinogen. In conclusion, our study demonstrated that the TNFRSF19 inhibited lung cancer carcinogenesis by competing with LRP6 to combine with Wnt3a to inhibit the Wnt/β-catenin signaling pathway.

IMPLICATIONS

These findings revealed a novel anti-lung cancer mechanism, highlighting the special significance of TNFRSF19 gene within the 13q12.12 risk locus in lung cancer pathogenesis.