Hypoxia-induced RBBP7 promotes esophagus cancer progression by inducing CDK4 expression

Identification of a chromatin regulator signature and potential candidate drugs for primary open-angle glaucoma

AIMS

This research aims to establish a chromatin regulator (CR) signature to provide new epigenetic insights into the pathogenesis of primary open-angle glaucoma (POAG).

MATERIALS & METHODS

The expression profile of CRs in trabecular meshwork (TM) tissues was analyzed by bioinformatics analysis; The selected hub CRs were further verified by cell experiments.

RESULTS

We found the immune microenvironment of the TMwas changed in POAG patients and identified 3 differentially expressed CRs that were relevant to immunity. Then, we successfully constructed and proved a predicted signature based on these 3 CRs, which could effectively predict the risk of POAG. The genes co-expressed with these 3 CRs and miRNAs with are gulatory relationship were identified, and a miRNA-hub CR network was successfully constructed. The results of the Gene Set Enrichment analysis indicated that these 3 hub CRs were all associated with neurodegenerative diseases. Moreover, the human trabecular meshwork cell (HTMC) oxidative stress model was constructed, and KDM5B was significantly down-regulated in this cell model. Finally, we found 10 agents that might be helpful for patients with POAG.

CONCLUSIONS

Dysregulation of CR expression in TM tissues may be involved in the occurrence and progression of POAG through multiple mechanisms.

IKZF1 promotes pyroptosis and prevents M2 macrophage polarization by inhibiting JAK2/STAT5 pathway in colon cancer

Pyroptosis and macrophage pro-inflammatory activation play an important role in hepatocellular carcinoma (HCC) progression. However, the specific regulatory mechanisms remain unclear. We identified pyroptosis-related differentially expressed genes (DEGs) based on the GSE4183 and GSE44861 datasets as well as EVenn database. Expression levels of key genes were detected by qRT-PCR. IKZF1 was overexpressed in colon cancer cells and tumor-bearing mice, and its functions were assessed by various cell biology assays in vitro and in vivo. To investigate the interactions between IKZF1 and macrophages, a co-culture system was constructed. The activator RO8191 or inhibitor ruxolitinib of the JAK/STAT pathway was employed to confirm whether IKZF1 inhibited colon cancer development by regulating JAK2/STAT5 pathway. Pyroptosis-related hub genes RBBP7, HSP90AB1, and RBBP4 were highly expressed, while IKZF1, NLRP1, and PYCARD were lowly expressed. These hub genes had good performance in distinguishing colon cancer from controls. Furthermore, overexpression of IKZF1 inhibited tumor growth and promoted pyroptosis. Overexpression of IKZF1 suppressed cell proliferation, metastasis, and inactivated JAK2/STAT5 signaling pathway in colon cancer cells. Furthermore, upregulation of IKZF1 promoted M1 macrophage polarization while inhibiting M2 macrophage polarization in vivo and in vitro by inhibiting the JAK2/STAT5 signaling pathway. This study identifies IKZF1 as a potential biomarker inactivating JAK2/STAT5 pathway for colon cancer.

HADHA promotes esophageal cancer progression by activating mTOR signaling and the SP1/MDM2 axis

Esophageal cancer (EC) is one of the most recalcitrant cancers, with a 5-year survival rate of < 30%. The hydroxyacyl-CoA dehydrogenase alpha subunit (HADHA) plays an essential role in long-chain fatty acid metabolism, and dysregulation of HADHA has been demonstrated to be involved in a series of metabolic diseases and cancers. However, its role in cancers remains controversial. HADHA has seldom been investigated in EC, and little is known about how HADHA regulates the malignant progression of EC. In this study, we find that HADHA is significantly upregulated in EC tissues and is correlated with poor survival. HADHA knockdown markedly inhibits EC cell proliferation both in vitro and in vivo. The loss of HADHA also induces EC cell apoptosis, causes cell cycle arrest and inhibits cell migration. Additionally, RNA profiling reveals that mTOR signaling is significantly suppressed after HADHA knockdown. Mechanistically, HADHA interacts with SP1 and induces MDM2 expression. In conclusion, both mTOR signaling and the SP1-MDM2 axis participate in the HADHA-induced malignant behavior of EC cells.

Hypoxia exposure induces lactylation of Axin1 protein to promote glycolysis of esophageal carcinoma cells

The hypoxic microenvironment in esophageal carcinoma is an important factor promoting the rapid progression of malignant tumor. This study was to investigate the lactylation of Axin1 on glycolysis in esophageal carcinoma cells under hypoxia exposure. Hypoxia treatment increases pan lysine lactylation (pan-kla) levels of both TE1 and EC109 cells. Meanwhile, ECAR, glucose consumption and lactate production were also upregulated in both TE1 and EC109 cells. The expression of embryonic stem cell transcription factors NANOG and SOX2 were enhanced in the hypoxia-treated cells. Axin1 overexpression partly reverses the induction effects of hypoxia treatment in TE1 and EC109 cells. Moreover, lactylation of Axin1 protein at K147 induced by hypoxia treatment promotes ubiquitination modification of Axin1 protein to promote glycolysis and cell stemness of TE1 and EC109 cells. Mutant Axin1 can inhibit ECAR, glucose uptake, lactate secretion, and cell stemness in TE1 and EC109 cells under normal or hypoxia conditions. Meanwhile, mutant Axin1 further enhanced the effects of 2-DG on inhibiting glycolysis and cell stemness. Overexpression of Axin1 also inhibited tumor growth in vivo, and was related to suppressing glycolysis. In conclusion, hypoxia treatment promoted the glycolysis and cell stemness of esophageal carcinoma cells, and increased the lactylation of Axin1 protein. Overexpression of Axin1 functioned as a glycolysis inhibitor, and suppressed the effects of hypoxia exposure in vitro and inhibited tumor growth in vivo. Mechanically, hypoxia induces the lactylation of Axin1 protein and promotes the ubiquitination of Axin1 to degrade the protein, thereby exercising its anti-glycolytic function.

Hypoxia-associated autophagy flux dysregulation in human cancers

A general feature of cancer is hypoxia, determined as low oxygen levels. Low oxygen levels may cause cells to alter in ways that contribute to tumor growth and resistance to treatment. Hypoxia leads to variations in cancer cell metabolism, angiogenesis and metastasis. Furthermore, a hypoxic tumor microenvironment might induce immunosuppression. Moreover, hypoxia has the potential to impact cellular processes, such as autophagy. Autophagy refers to the catabolic process by which damaged organelles and toxic macromolecules are broken down. The abnormal activation of autophagy has been extensively recorded in human tumors and it serves as a regulator of cell growth, spread to other parts of the body, and resistance to treatment. There is a correlation between hypoxia and autophagy in human malignancies. Hypoxia can regulate the activity of AMPK, mTOR, Beclin-1, and ATGs to govern autophagy in human malignancies. Furthermore, HIF-1α, serving as an indicator of low oxygen levels, controls the process of autophagy. Hypoxia-induced autophagy has a crucial role in regulating the growth, spread, and resistance to treatment in human malignancies. Hypoxia-induced regulation of autophagy can impact other mechanisms of cell death, such as apoptosis. Chemoresistance and radioresistance have become significant challenges in recent years. Hypoxia-mediated autophagy plays a crucial role in determining the response to these therapeutic treatments.

Identification of cytokines in benign and malignant thymus tumors: based on Mendelian randomization and proteomics

Objective

The aim of this study was to identify potential causal cytokines in thymic malignancies and benign tumors from the FinnGen database using Mendelian randomization (MR).

Methods

In this study, data from genome-wide association studies (GWAS) of 91 cytokines were used as exposure factors, and those of thymic malignant tumors and thymic benign tumors were the outcome variables. Two methods were used to determine the causal relationship between exposure factors and outcome variables: inverse variance weighting (IVW) and MR-Egger regression. Sensitivity analysis was performed using three methods, namely, the heterogeneity test, the pleiotropy test, and the leave-one-out test.

Results

There was a causal relationship between the expression of fibroblast growth factor 5, which is a risk factor for thymic malignant tumors, and thymic malignant tumors. C-C motif chemokine 19 expression, T-cell surface glycoprotein CD5 levels, and interleukin-12 subunit beta levels were causally related to thymic malignant tumors and were protective. Adenosine deaminase levels, interleukin-10 receptor subunit beta expression, tumor necrosis factor (TNF)-related apoptosis-inducing ligand levels, and TNF-related activation-induced cytokine levels showed a causal relationship with thymic benign tumors, which are its risk factors. Caspase 8 levels, C-C motif chemokine 28 levels, interleukin-12 subunit beta levels, latency-associated peptide transforming growth factor beta 1 levels, and programmed cell death 1 ligand 1 expression showed a causal relationship with thymic benign tumors, which are protective factors. Sensitivity analysis showed no heterogeneity.

Conclusion

Cytokines showed a causal relationship with benign and malignant thymic tumors. Interleukin-12 subunit beta is a common cytokine that affects malignant and benign thymic tumors.

Interpreting the molecular mechanisms of RBBP4/7 and their roles in human diseases (Review)

Histone chaperones serve a pivotal role in maintaining human physiological processes. They interact with histones in a stable manner, ensuring the accurate and efficient execution of DNA replication, repair and transcription. Retinoblastoma binding protein (RBBP)4 and RBBP7 represent a crucial pair of histone chaperones, which not only govern the molecular behavior of histones H3 and H4, but also participate in the functions of several protein complexes, such as polycomb repressive complex 2 and nucleosome remodeling and deacetylase, thereby regulating the cell cycle, histone modifications, DNA damage and cell fate. A strong association has been indicated between RBBP4/7 and some major human diseases, such as cancer, age‑related memory loss and infectious diseases. The present review assesses the molecular mechanisms of RBBP4/7 in regulating cellular biological processes, and focuses on the variations in RBBP4/7 expression and their potential mechanisms in various human diseases, thus providing new insights for their diagnosis and treatment.

Analysis of weighted gene co-expression networks and clinical validation identify hub genes and immune cell infiltration in the endometrial cells of patients with recurrent implantation failure

Background

About 10% of individuals undergoing in vitro fertilization encounter recurrent implantation failure (RIF), which represents a worldwide social and economic concern. Nevertheless, the critical genes and genetic mechanisms underlying RIF are largely unknown.

Methods

We first obtained three comprehensive microarray datasets "GSE58144, GSE103465 and GSE111974". The differentially expressed genes (DEGs) evaluation, enrichment analysis, as well as efficient weighted gene co-expression network analysis (WGCNA), were employed for distinguishing RIF-linked hub genes, which were tested by RT-qPCR in our 30 independent samples. Next, we studied the topography of infiltration of 22 immune cell subpopulations and the association between hub genes and immune cells in RIF using the CIBERSORT algorithm. Finally, a novel ridge plot was utilized to exhibit the potential function of core genes.

Results

The enrichment of GO/KEGG pathways reveals that Herpes simplex virus 1 infection and Salmonella infection may have an important role in RIF. After WGCNA, the intersected genes with the previous DEGs were obtained using both variance and association. Notably, the subsequent nine hub genes were finally selected: ACTL6A, BECN1, SNRPD1, POLR1B, GSK3B, PPP2CA, RBBP7, PLK4, and RFC4, based on the PPI network and three different algorithms, whose expression patterns were also verified by RT-qPCR. With in-depth analysis, we speculated that key genes mentioned above might be involved in the RIF through disturbing endometrial microflora homeostasis, impairing autophagy, and inhibiting the proliferation of endometrium. Furthermore, the current study revealed the aberrant immune infiltration patterns and emphasized that uterine NK cells (uNK) and CD4+ T cells were substantially altered in RIF endometrium. Finally, the ridge plot displayed a clear and crucial association between hub genes and other genes and key pathways.

Conclusion

We first utilized WGCNA to identify the most potential nine hub genes which might be associated with RIF. Meanwhile, this study offers insights into the landscape of immune infiltration status to reveal the underlying immune pathogenesis of RIF. This may be a direction for the next study of RIF etiology. Further studies would be required to investigate the involved mechanisms.

RBBP7, regulated by SP1, enhances the Warburg effect to facilitate the proliferation of hepatocellular carcinoma cells via PI3K/AKT signaling

BACKGROUND

Hepatocellular carcinoma (HCC) is characterized by aggressive progression and elevated mortality rates. This study aimed to investigate the regulatory effects of RBBP7 on HCC pathogenesis and the underlying mechanisms.

METHODS

The expression and clinical feature of RBBP7 were evaluated using bioinformatics analysis and the assessment of clinical HCC samples. CCK8 and colony formation were employed to estimate cell proliferation function of RBBP7. Aerobic glycolysis levels of RBBP7 were evaluated by measuring ATP levels, lactic acid production, glucose uptake capacity, and the expression of relevant enzymes (PFKM, PKM2, and LDHA). The phosphorylation levels in PI3K/AKT signaling were measured by western blotting. The regulatory effect of transcription factors of specificity protein 1 (SP1) on RBBP7 mRNA expression was confirmed in dual-luciferase reporter assays and chromatin immunoprecipitation experiments. The proliferation- and glycolysis-associated proteins were assessed using immunofluorescence staining in vivo.

RESULTS

We found that RBBP7 is expressed at high levels in HCC and predicts poor survival. Functional assays showed that RBBP7 promoted HCC proliferation and glycolysis. Mechanistically, it was demonstrated that RBBP7 activates the PI3K/AKT pathway, a crucial pathway in glycolysis, contributing to the progression of HCC. The outcomes of the dual-luciferase assay further confirmed that SP1 is capable of activating the promoter of RBBP7.

CONCLUSIONS

RBBP7, which is up-regulated by SP1, promotes HCC cell proliferation and glycolysis through the PI3K/AKT pathway. The findings of this study suggest that RBBP7 is a potential biomarker for HCC.

Unveiling the molecular structure and role of RBBP4/7: implications for epigenetic regulation and cancer research

Retinoblastoma-binding protein (RBBP) family is a class of proteins that can interact with tumor suppressor retinoblastoma protein (pRb). RBBP4 and RBBP7 are the only pair of homologous proteins in this family, serving as scaffold proteins whose main function is to offer a platform to indirectly connect two proteins. This characteristic allows them to extensively participate in the binding of various proteins and epigenetic complexes, indirectly influencing the function of effector proteins. As a result, they are often highlighted in organism activities involving active epigenetic modifications, such as embryonic development and cancer activation. In this review, we summarize the structural characteristics of RBBP4/7, the complexes they are involved in, their roles in embryonic development and cancer, as well as potential future research directions, which we hope to inspire the field of epigenetic research in the future.