GADD45G Interacts with E-cadherin to Suppress the Migration and Invasion of Esophageal Squamous Cell Carcinoma

The role of GADD45G methylation in endometrial cancer: Insights into CDK1/CCNB1 activation and therapeutic opportunities

INTRODUCTION

Accumulating evidence suggests the significant involvement of GADD45G in the development of various cancers. This study investigates GADD45G's involvement and methylation status in endometrial cancer (EC), along with molecular mechanisms and potential therapies.

METHODS

The expression of GADD45G in EC tissues and controls was evaluated using RNA-seq, quantitative real-time polymerase chain reaction (qRT-PCR), and western blotting (WB). Methylation-specific PCR (MSP) evaluated GADD45G's methylation status. Protein-protein interaction (PPI) prediction identified potential interactors of GADD45G, and co-immunoprecipitation (co-IP) confirmed GADD45G interact with Cyclin-dependent kinase 1 (CDK1) and cyclin B1 (CCNB1). Several cell behavior assays were conducted in both in vitro and in vivo settings to comprehensively understand the impact of GADD45G dysregulation in EC.

RESULTS

Our findings revealed a significant decrease in the expression of GADD45G in endometrial cancer tissues and cells, which was attributed to its methylation status. Reduced GADD45G expression correlated with increased invasive behaviors in EC cells. Furthermore, GADD45G negatively regulated CDK1 and CCNB1, promoting invasive behaviors at transcript and protein levels.

CONCLUSION

This study demonstrated that the downregulation of GADD45G, mediated by methylation, facilitates the invasive behaviors of EC cells through interaction with the CDK1/CCNB1. These findings enhance understanding of the molecular mechanisms underlying endometrial cancer and suggest potential therapeutic strategies targeting GADD45G for treatment.

Identify GADD45G as a potential target of 4-methoxydalbergione in treatment of liver cancer: bioinformatics analysis and in vivo experiment

BACKGROUND

The growth arrest and DNA damage-inducible gene gamma (GADD45G), an important member of GADD45 family, has been connected to the development of certain human cancers. Our previous studies have confirmed that GADD45G expression could be upregulated by 4-methoxydalbergione (4MOD) in liver cancer cells, but its potential pathological role in hepatocellular carcinoma (HCC) has not been fully understood. This study aimed to determine potential role of GADD45G in HCC, and the effects of 4-methoxydalbergione (4MOD) on the regulation of GADD45G expression in vivo were also analyzed.

METHODS

Publicly available data and in-house immunohistochemistry (IHC) experiments were utilized to explore the expression profiles and clinical significance of GADD45G in HCC samples. Functional enrichment analysis based on GADD45G co-expression genes was used to excavate the molecular mechanism of GADD45G in HCC. We also conducted in vivo experiment on BALB/c nude mice to excavate the inhibitory effect of 4MOD on HCC and to evaluate the differences in the expression of GADD45G in xenograft tissues between the 4MOD-treated and untreated groups.

RESULTS

GADD45G displayed significant low expression in HCC tissues. Downregulated expression of GADD45G was positively correlated with some high risk factors in HCC patients and predicted worse prognosis of HCC patients. There was a close association of GADD45G mRNA expression and immune cells, including neutrophils, NK cells, CD8 T cells, and macrophages. Co-expressed genes of GADD45G were involved in several pathways including cell cycle, carbon metabolism, and peroxisome. 4MOD could significantly suppress the growth of HCC in vivo, and this inhibitory effect was dependent on the upregulation of GADD45G expression.

CONCLUSION

GADD45G expression can be used as a new clinical biomarker for HCC and GADD45G may be a potential target for the anti-cancer effect of 4MOD in liver cancer.

4-Methoxydalbergione Elicits Anticancer Effects by Upregulation of GADD45G in Human Liver Cancer Cells

Background

4-Methoxydalbergione (4MOD) is a flavonoid isolated from the heartwood of Dalbergia. Studies have demonstrated that 4MOD exerts anticancer activities on bladder cancer and astrocytoma. However, the anticancer activity of 4MOD in hepatocellular carcinoma (HCC) remains unknown. This study aims to examine its anticancer activities and mechanisms in human liver cancer cells.

Methods

CCK-8, colony forming, wound healing, transwell migration, and AnnexinV/PI assays were used to assess the anticancer effects of 4MOD in HCC cells. RNA sequencing (RNA-Seq) was selected to explore the possible mechanisms underlying the anti-HCC activity of 4MOD. The mRNA expression levels of target genes were verified through quantitative real-time PCR (qRT-PCR). A lentiviral shRNA interference technique was used to silence GADD45G expression. GADD45G knockdown was employed to confirm the crucial role of GADD45G in the 4MOD-mediatedanti-HCC effects.

Results

4MOD inhibited HCC cells' proliferation and migration and promoted tumor cell apoptosis. RNA-Seq and qRT-PCR analyses revealed that 4MOD treatment increased GADD45G expression. Silencing GADD45G reversed 4MOD-mediated inhibition of proliferation, migration, and promotion of apoptosis.

Conclusions

Our findings show that 4MOD elicits anti-HCC effects by upregulating GADD45G expression and could be a valuable anticancer agent for liver cancer.

Simulated Microgravity Modulates Focal Adhesion Gene Expression in Human Neural Stem Progenitor Cells

We analyzed the morphology and the transcriptomic changes of human neural stem progenitor cells (hNSPCs) grown on laminin in adherent culture conditions and subjected to simulated microgravity for different times in a random positioning machine apparatus. Low-cell-density cultures exposed to simulated microgravity for 24 h showed cell aggregate formation and significant modulation of several genes involved in focal adhesion, cytoskeleton regulation, and cell cycle control. These effects were much more limited in hNSPCs cultured at high density in the same conditions. We also found that some of the genes modulated upon exposure to simulated microgravity showed similar changes in hNSPCs grown without laminin in non-adherent culture conditions under normal gravity. These results suggest that reduced gravity counteracts the interactions of cells with the extracellular matrix, inducing morphological and transcriptional changes that can be observed in low-density cultures.

GADD45 in Stress Signaling, Cell Cycle Control, and Apoptosis

GADD45 is a gene family consisting of GADD45A, GADD45B, and GADD45G that is often induced by DNA damage and other stress signals associated with growth arrest and apoptosis. Many of these roles are carried out via signaling mediated by p38 mitogen-activated protein kinases (MAPKs). The GADD45 proteins can contribute to p38 activation either by activation of upstream kinase(s) or by direct interaction, as well as suppression of p38 activity in certain cases. In vivo, there are important tissue and cell type specific differences in the roles for GADD45 in MAPK signaling. In addition to being p53-regulated, GADD45A has also been found to contribute to p53 activation via p38. Like other stress and signaling proteins, GADD45 proteins show complex regulation and numerous effectors. More recently, aberrant GADD45 expression has been found in several human cancers, but the mechanisms behind these findings largely remain to be understood.

Changes in gene expression in rat placenta at gestational day 16.5 in response to hyperglycemia

Gestational diabetes mellitus (GDM) is a serious pregnancy complication. Hyperglycemia induces abnormal placental development and function. However, the mechanism is unclear. Previous research showed streptozocin (STZ) injection sustained hyperglycemia throughout pregnancy in rodents. Our current results showed that the placenta from hyperglycemic STZ-treated rats was about 20% heavier than that of controls. The relative thickness of each layer of the placenta was also significantly different on gestational day (GD) 16.5. Gene expression was analyzed by RNA sequencing to explore reasons for the abnormal placenta. In total, 2100 differential expressed genes (DEGs), including 1327 up-regulated and 773 down-regulated genes, were identified. Gene ontogeny (GO) analysis revealed DEGs involved in developmental process, growth, metabolic process, cell junction, molecular transducer activity and signaling. By KEGG analysis, DEGs were mainly related to the endocrine system, development, signal transduction and cell growth and death. The KEGG results were partly consistent with GO results, with DEGs mainly focused on biochemical signal pathways such as cell growth and death (e.g., Abl1, Bbc3 and Camk2d), and signal transduction (e.g., Abl1, Ceacam1 and Arnt). These genes may play a dominant role in abnormal cell proliferation and signaling disorders. These results suggest that DEGs play a role in diabetic-induced placental abnormalities. One or more of these DEGs may be involved in the etiology of placental weight increase caused by hyperglycemia.

MicroRNAs and Corresponding Targets in Esophageal Cancer as Shown In Vitro and In Vivo in Preclinical Models

Squamous cell carcinoma of the esophagus is associated with a dismal prognosis. Therefore, identification of new targets and implementation of new treatment modalities are issues of paramount importance. Based on a survey of the literature, we identified microRNAs conferring antitumoral activity in preclinical in vivo experiments. In the category of miRs targeting secreted factors and transmembrane receptors, four miRs were up-regulated and 10 were down-regulated compared with five out of nine in the category transcription factors, and six miRs were down-regulated in the category enzymes, including metabolic enzymes. The down-regulated miRs have targets which can be inhibited by small molecules or antibody-related entities, or re-expressed by reconstitution therapy. Up-regulated miRs have targets which can be reconstituted with small molecules or inhibited with antagomirs.

Gadd45g initiates embryonic stem cell differentiation and inhibits breast cell carcinogenesis

Many self-renewal-promoting factors of embryonic stem cells (ESCs) have been implicated in carcinogenesis, while little known about the genes that direct ESCs exit from pluripotency and regulate tumor development. Here, we show that the transcripts of Gadd45 family genes, including Gadd45a, Gadd45b, and Gadd45g, are gradually increased upon mouse ESC differentiation. Upregulation of Gadd45 members decreases cell proliferation and induces endodermal and trophectodermal lineages. In contrast, knockdown of Gadd45 genes can delay mouse ESC differentiation. Mechanistic studies reveal that Gadd45g activates MAPK signaling by increasing expression levels of the positive modulators of this pathway, such as Csf1r, Igf2, and Fgfr3. Therefore, inhibition of MAPK signaling with a MEK specific inhibitor is capable of eliminating the differentiation phenotype caused by Gadd45g upregulation. Meanwhile, GADD45G functions as a suppressor in human breast cancers. Enforced expression of GADD45G significantly inhibits tumor formation and breast cancer metastasis in mice through limitation of the propagation and invasion of breast cancer cells. These results not only expand our understanding of the regulatory network of ESCs, but also help people better treatment of cancers by manipulating the prodifferentiation candidates.

A Prognostic DNA Damage Repair Genes Signature and Its Impact on Immune Cell Infiltration in Glioma

Objective

Glioma is the most frequent type of malignant cerebral tumors. DNA damage repair genes (DDRGs) play a crucial role in the development of cancer. In this study, we constructed a DDRGs signature and investigated the potential mechanisms involved in this disease.

Methods

RNA sequence data, microarray data, and corresponding clinical information of gliomas were downloaded from The Cancer Genome Atlas (TCGA), Chinese Glioma Genome Atlas (CGGA), and Gene Expression Omnibus (GEO). Subsequently, we identified candidate genes by differential analysis and Cox regression analysis. The least absolute shrinkage and selection operator Cox regression model was utilized to construct a DDRGs signature using TCGA training dataset. According to this signature, patients with glioma were divided into low- and high-risk groups. The predictive ability of the signature was validated by prognostic analysis, receiver operating characteristic curves, principal component analysis, and stratification analysis in TCGA testing and CGGA verification datasets. CIBERSORT and single-sample gene set enrichment analysis (ssGSEA) were used to evaluate the immune microenvironment of glioma. Moreover, we conducted GSEA to determine the functions and pathways in the low- and high-risk groups. Finally, a nomogram was constructed by combining the signature and other clinical features.

Results

A total of 1,431 samples of glioma (592 from TCGA, 686 from the CGGA, and 153 from the GEO) and 23 samples of normal brain tissue from the GEO were analyzed in this study. There were 51 prognostic differentially expressed DDRGs. Additionally, five DDRGs (CDK4、HMGB2、WEE1、SMC3 and GADD45G) were selected to construct a DDRGs signature for glioma, stratifying patients into low- and high-risk groups. The survival analysis showed that the DDRGs signature could differentiate the outcome of the low- and high-risk groups, showing that high-risk gliomas were associated with shorter overall survival. The immune microenvironment analysis revealed that more immunosuppressive cells, such as tumor associated macrophages and regulatory T cells, were recruited in the high-risk group. GSEA also showed that high-risk glioma was correlated with the immune and extracellular matrix pathways.

Conclusion

The five DDRGs signature and its impact on the infiltration of immunosuppressive cells could precisely predict the prognosis and provide guidance on the treatment of glioma.

Construction and analysis of competing endogenous RNA network of MCF-7 breast cancer cells based on the inhibitory effect of 6-thioguanine on cell proliferation

Previous research has proven that 6-thioguanine (6-TG) inhibits the growth of MCF-7 breast cancer cells. Accumulating evidence indicates that long non-coding (lnc)RNAs are involved in the development of various cancer types as competitive endogenous (ce)RNA molecules. The present study was conducted to investigate the regulatory mechanism underlying the function of lncRNAs as ceRNA molecules in MCF-7 cells and to identify more effective prognostic biomarkers for breast cancer treatment. The expression profiles of lncRNAs in untreated MCF-7 cells and 6-TG-treated MCF-7 cells were compared by RNA-seq. The regulatory associations among lncRNAs, micro (mi)RNAs and mRNAs were analyzed and verified by the TargetScan, miRDB and miRTarBas databases. The ceRNA networks were constructed by Cytoscape. The expression levels of two lncRNAs and two miRNAs in the ceRNA network were measured by reverse transcription-quantitative PCR. The OncoLnc and Kaplan-Meier plotter network databases were utilized to determine the effects of lncRNA and miRNA expression on the survival of patients with breast cancer. A ceRNA network was constructed for MCF-7 breast cancer cells treated with 6-TG, and this network may provide valuable information for further research elucidating the molecular mechanism underlying the effects of 6-TG on breast cancer. Moreover, LINC00324, MIR22HG, miR-370-3p and miR-424-5p were identified as potential prognostic and therapeutic biomarkers for breast cancer.