Functional role of SGK3 in PI3K/Pten driven liver tumor development

Role of Protein Tyrosine Phosphatase Receptor Type E (PTPRE) in Chemoresistant Retinoblastoma

Protein tyrosine phosphatase receptor type E (PTPRE) is a member of the "classical" protein tyrosine phosphatase subfamily and regulates a variety of cellular processes in a tissue-specific manner by antagonizing the function of protein tyrosine kinases. PTPRE plays a tumorigenic role in different human cancer cells, but its role in retinoblastoma (RB), the most common malignant eye cancer in children, remains to be elucidated. Etoposide-resistant RB cell lines and RB patients display significant higher PTPRE expression levels compared to chemosensitive counterparts and the healthy human retina, respectively. PTPRE promotor methylation analyses revealed that PTPRE expression in RB is not regulated via this mechanism. Lentiviral PTPRE knockdown (KD) induced a significant decrease in growth kinetics, cell viability, and anchorage-independent growth of etoposide-resistant Y79 and WERI RB cells. Caspase-dependent apoptosis rates were significantly increased and a re-sensitization for etoposide could be observed after PTPRE depletion. In vivo chicken chorioallantoic membrane (CAM) assays revealed decreased tumor formation capacity as well as reduced tumor size and weight following PTPRE KD. Expression levels of miR631 were significantly downregulated in etoposide-resistant RB cells and patients. Transient miR631 overexpression resulted in significantly decreased PTPRE levels and concomitantly decreased proliferation and increased apoptosis levels in etoposide-resistant RB cells. These impacts mirror PTPRE KD effects, indicating a regulation of PTPRE via this miR. Additionally, PTPRE KD led to altered phosphorylation of protein kinase SGK3 and-dependent on the cell line-AKT and ERK1/2, suggesting potential PTPRE downstream signaling pathways. In summary, these results indicate an oncogenic role of PTPRE in chemoresistant retinoblastoma.

The SGK3-Catalase antioxidant signaling axis drives cervical cancer growth and therapy resistance

Cancer cells frequently exhibit aberrant redox homeostasis and adaptation to oxidative stress. Hence abrogation of redox adaptation in cancer cells can be exploited for therapeutic benefit. Here we report SGK3 functions as an anti-oxidative factor to promote cell growth and drug resistance in cervical cancers harboring PIK3CA helical domain mutations. Mechanistically, SGK3 is activated upon oxidative stress and exerts anti-ROS activity by stabilizing and activating the antioxidant enzyme catalase. SGK3 interacts with and phosphorylates catalase, promoting its tetrameric state and activity. Meanwhile, SGK3 phosphorylates GSK3β and protects catalase from GSK3β-β-TrCP mediated ubiquitination and proteasomal degradation. Furthermore, SGK3 inhibition not only potentiates CDK4/6 inhibitor Palbociclib-mediated cytotoxicity, but also overcomes cisplatin resistance through ROS-mediated mechanisms. These data uncover the role of SGK3 in maintaining redox homeostasis and suggest that the SGK3-catalase antioxidant signaling axis may be therapeutically targeted to improve treatment efficacy for cervical cancers carrying PIK3CA helical domain mutations.

SGK3 overexpression correlates with a poor prognosis in endoscopically resected superficial esophageal squamous cell neoplasia: A long-term study

BACKGROUND

The expression status of serum and glucocorticoid-induced protein kinase 3 (SGK3) in superficial esophageal squamous cell neoplasia (ESCN) remains unknown.

AIM

To evaluate the SGK3 overexpression rate in ESCN and its influence on the prognosis and outcomes of patients with endoscopic resection.

METHODS

A total of 92 patients who had undergone endoscopic resection for ESCN with more than 8 years of follow-up were enrolled. Immunohistochemistry was used to evaluate SGK3 expression.

RESULTS

SGK3 was overexpressed in 55 (59.8%) patients with ESCN. SGK3 overexpression showed a significant correlation with death (P = 0.031). Overall survival and disease-free survival rates were higher in the normal SGK3 expression group than in the SGK3 overexpression group (P = 0.013 and P = 0.004, respectively). Cox regression analysis models demonstrated that SGK3 overexpression was an independent predictor of poor prognosis in ESCN patients (hazard ratio 4.729; 95% confidence interval: 1.042-21.458).

CONCLUSION

SGK3 overexpression was detected in the majority of patients with endoscopically resected ESCN and was significantly associated with shortened survival. Thus, it might be a new prognostic factor for ESCN.

Cortisol controls endoplasmic reticulum stress and hypoxia dependent regulation of insulin receptor and related genes expression in HEK293 cells

Objective. Glucocorticoids are important stress-responsive regulators of insulin-dependent metabolic processes realized through specific changes in genome function. The aim of this study was to investigate the impact of cortisol on insulin receptor and related genes expression in HEK293 cells upon induction the endoplasmic reticulum (ER) stress by tunicamycin and hypoxia. Methods. The human embryonic kidney cell line HEK293 was used. Cells were exposed to cortisol (10 µM) as well as inducers of hypoxia (dimethyloxalylglycine, DMOG; 0.5 mM) and ER stress (tunicamycin; 0.2 µg/ml) for 4 h. The RNA from these cells was extracted and reverse transcribed. The expression level of INSR, IRS2, and INSIG2 and some ER stress responsive genes encoding XBP1n, non-spliced variant, XBP1s, alternatively spliced variant of XBP1, and DNAJB9 proteins, was measured by quantitative polymerase chain reaction and normalized to ACTB. Results. We showed that exposure of HEK293 cells to cortisol elicited up-regulation in the expression of INSR and DNAJB9 genes and down-regulation of XBP1s, XBP1n, IRS2, and INSIG2 mRNA levels. At the same time, induction of hypoxia by DMOG led to an up-regulation of the expression level of most studied mRNAs: XBP1s and XBP1n, IRS2 and INSIG2, but did not change significantly INSR and DNAJB9 gene expression. We also showed that combined impact of cortisol and hypoxia introduced the up-regulation of INSR and suppressed XBP1n mRNA expression levels. Furthermore, the exposure of HEK293 cells to tunicamycin affected the expression of IRS2 gene and increased the level of XBP1n mRNA. At the same time, the combined treatment of these cells with cortisol and inductor of ER stress had much stronger impact on the expression of all the tested genes: strongly increased the mRNA level of ER stress dependent factors XBP1s and DNAJB9 as well as INSR and INSIG2, but down-regulated IRS2 and XBP1n. Conclusion. Taken together, the present study indicates that cortisol may interact with ER stress and hypoxia in the regulation of ER stress dependent XBP1 and DNAJB9 mRNA expression as well as INSR and its signaling and that this corticosteroid hormone modified the impact of hypoxia and especially tunicamycin on the expression of most studied genes in HEK293 cells. These data demonstrate molecular mechanisms of glucocorticoids interaction with ER stress and insulin signaling at the cellular level.

scBPGRN: Integrating single-cell multi-omics data to construct gene regulatory networks based on BP neural network

The deterioration and metastasis of cancer involve various aspects of genomic changes, including genomic DNA changes, epigenetic modifications, gene expression, and other complex interactions. Therefore, integrating single-cell multi-omics data to construct gene regulatory networks containing more omics information is of great significance for understanding the pathogenesis of cancer. In this article, an algorithm integrating single-cell RNA sequencing data and DNA methylation data to construct a gene regulatory network based on the back-propagation (BP) neural network (scBPGRN) is proposed. This algorithm uses biweight extreme correlation coefficients to measure the correlation between factors and uses neural networks to calculate generalized weights to construct gene regulation networks. Finally, the node strength is calculated to identify the genes associated with cancer. We apply the scBPGRN algorithm to hepatocellular carcinoma (HCC) data. We construct a regulatory network and identify top-ranked genes, such as MYCBP, KLHL35, PRKCZ, and SERPINA6, as the key HCC-related genes. We analyze the top 100 genes, and the HCC-related genes are concentrated in the top 20. In addition, the single cell data is found to consist of two subpopulations. We also apply scBPGRN to two subpopulations. We analyze the top 50 genes in them, and the HCC-related genes are concentrated in the top 20. The consequences of functional enrichment analysis indicate that the gene regulatory network we have constructed is valid. Our results have been verified in several pieces of literature. This study provides a reference for the integration of single-cell multi-omics data to construct gene regulatory networks.

Metabolic recycling of storage lipids promotes squalene biosynthesis in yeast

BACKGROUND

Metabolic rewiring in microbes is an economical and sustainable strategy for synthesizing valuable natural terpenes. Terpenes are the largest class of nature-derived specialized metabolites, and many have valuable pharmaceutical or biological activity. Squalene, a medicinal terpene, is used as a vaccine adjuvant to improve the efficacy of vaccines, including pandemic coronavirus disease 2019 (COVID-19) vaccines, and plays diverse biological roles as an antioxidant and anticancer agent. However, metabolic rewiring interferes with inherent metabolic pathways, often in a way that impairs the cellular growth and fitness of the microbial host. In particular, as the key starting molecule for producing various compounds including squalene, acetyl-CoA is involved in numerous biological processes with tight regulation to maintain metabolic homeostasis, which limits redirection of metabolic fluxes toward desired products.

RESULTS

In this study, focusing on the recycling of surplus metabolic energy stored in lipid droplets, we show that the metabolic recycling of the surplus energy to acetyl-CoA can increase squalene production in yeast, concomitant with minimizing the metabolic interferences in inherent pathways. Moreover, by integrating multiple copies of the rate-limiting enzyme and implementing N-degron-dependent protein degradation to downregulate the competing pathway, we systematically rewired the metabolic flux toward squalene, enabling remarkable squalene production (1024.88 mg/L in a shake flask). Ultimately, further optimization of the fed-batch fermentation process enabled remarkable squalene production of 6.53 g/L.

CONCLUSIONS

Our demonstration of squalene production via engineered yeast suggests that plant- or animal-based supplies of medicinal squalene can potentially be complemented or replaced by industrial fermentation. This approach will also provide a universal strategy for the more stable and sustainable production of high-value terpenes.

O2-(2,4-dinitrophenyl) diazeniumdiolate derivative induces G2/M arrest via PTEN-mediated inhibition of PI3K/Akt pathway in hepatocellular carcinoma cells

OBJECTIVES

The study aimed to investigate whether G2/M arrest caused by O2-(2,4-dinitrophenyl) diazeniumdiolate derivative (JS-K) was related to PTEN-mediated inhibition of PI3K/Akt pathway in hepatocellular carcinoma cells.

METHODS

The cell apoptosis was detected by DAPI staining and Annexin V-FITC/PI dual staining. The cell cycle was analysed by PI staining. The expressions of cell cycle-related proteins, PTEN and PI3K/AKT pathway were measured by Western blot. The rat model of primary hepatic carcinoma was established with diethylnitrosamine to verify the antitumour effects of JS-K.

KEY FINDINGS

The morphological features of apoptosis were obviously reversed when the cells were pre-treated with bpv(pic), followed by treatment with JS-K. JS-K mediated G2/M arrest and down-regulated expressions of cyclin B1. Meanwhile, it up-regulated the expression of p-Cdk1, p-Chk2 and p-CDC25C while down-regulated that of Cdk1 and CDC25C. Furthermore, JS-K also enhanced the expressions of p21 and p27, PTEN and p53 while decreased the expressions of p-PTEN, PI3K and p-AKT. However, bpv(pic) and Carboxy-PTIO could reverse JS-K-induced G2/M cell arrest and PTEN-mediated inhibition of the PI3K/AKT pathway. The same results were also testified in the rat model of primary hepatic carcinoma.

CONCLUSIONS

JS-K caused G2/M arrest through PTEN-mediated inhibition of the PI3K/AKT pathway involving Chk2/CDC25C/Cdk1 checkpoint.

RNA sequencing identified novel target genes for Adansonia digitata in breast and colon cancer cells

Adansonia digitata exhibits numerous beneficial effects. In the current study, we investigated the anti-cancer effects of four different extracts of A. digitata (polar and non-polar extracts of fruit powder and fibers) on the proliferation of human colon cancer (HCT116), human breast cancer (MCF-7), and human ovarian cancer (OVCAR-3 and OVCAR-4) cell lines. RNA sequencing revealed the influence of the effective A. digitata fraction on the gene expression profiles of responsive cells. The results indicated that only the polar extract of the A. digitata fibers exhibited anti-proliferative activities against HCT116 and MCF-7 cells, but not ovarian cancer cells. Moreover, the polar extract of the fibers resulted in the modulation of the expression of multiple genes in HCT116 and MCF-7 cells. We propose that casein kinase 2 alpha 3 (CSNK2A3) is a novel casein kinase 2 (CSNK2) isoform in HCT116 cells and report, for the first time, the potential involvement of FYVE, RhoGEF, and PH domain-containing 3 (FGD3) in colon cancer. Together, these findings provide evidence supporting the anti-cancer potential of the polar extract of A. digitata fibers in this experimental model of breast and colon cancers.

Oxymatrine inhibits the development of non-small cell lung cancer through miR-367-3p upregulation and target gene SGK3 downregulation

Oxymatrine (OM), an important active ingredient extracted from sophora flavescens, has attracted more attention for its anti-tumor effect in recent years, with pronounced effects on the development of multiple tumors, acting as a potential effective low toxic drug in clinical tumor treatment. In this study, CCK-8 and transwell experiments were applied to detect cell proliferation and migration. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used to test the expression of miR-367-3p and serum and glucocorticoid regulated kinase 3 (SGK3). The function of oxymatrine in non-small cell lung cancer (NSCLC) progression was also confirmed in vivo. Then, CCK-8 and transwell assays revealed that oxymatrine could repress NSCLC cell migration and proliferation. qRT-PCR showed the striking promotion roles of oxymatrine in cancer suppressor gene miR-367-3p expression. The results of further dual luciferase reporter gene experiment demonstrated that SGK3 was a target gene of miR-367-3p and under the regulation of oxymatrine. The rescue experiments indicated that OM functioned via miR-367-3p, while miR-367-3p exerted its function by action on SGK3. Finally, in vivo studies showed that OM could also inhibit tumor growth. As a result, this study found that OM inhibited the development of NSCLC through reducing the expression of a downstream target gene SGK3 by promoting miR-367-3p expression.

Genetically Engineered Mouse Models of Liver Tumorigenesis Reveal a Wide Histological Spectrum of Neoplastic and Non-Neoplastic Liver Lesions

Genetically engineered mouse models (GEMM) are an elegant tool to study liver carcinogenesis in vivo. Newly designed mouse models need detailed (histopathological) phenotyping when described for the first time to avoid misinterpretation and misconclusions. Many chemically induced models for hepatocarcinogenesis comprise a huge variety of histologically benign and malignant neoplastic, as well as non-neoplastic, lesions. Such comprehensive categorization data for GEMM are still missing. In this study, 874 microscopically categorized liver lesions from 369 macroscopically detected liver "tumors" from five different GEMM for liver tumorigenesis were included. The histologic spectrum of diagnosis included a wide range of both benign and malignant neoplastic (approx. 82%) and non-neoplastic (approx. 18%) lesions including hyperplasia, reactive bile duct changes or oval cell proliferations with huge variations among the various models and genetic backgrounds. Our study therefore critically demonstrates that models of liver tumorigenesis can harbor a huge variety of histopathologically distinct diagnosis and, depending on the genotype, notable variations are expectable. These findings are extremely important to warrant the correct application of GEMM in liver cancer research and clearly emphasize the role of basic histopathology as still being a crucial tool in modern biomedical research.

Screening of significant biomarkers with poor prognosis in hepatocellular carcinoma via bioinformatics analysis

Hepatocellular carcinoma (HCC) is a malignant tumor with unsatisfactory prognosis. The abnormal genes expression is significantly associated with initiation and poor prognosis of HCC. The aim of the present study was to identify molecular biomarkers related to the initiation and development of HCC via bioinformatics analysis, so as to provide a certain molecular mechanism for individualized treatment of hepatocellular carcinoma.Three datasets (GSE101685, GSE112790, and GSE121248) from the GEO database were used for the bioinformatics analysis. Differentially expressed genes (DEGs) of HCC and normal liver samples were obtained using GEO2R online tools. Gene ontology term and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analysis were conducted via the Database for Annotation, Visualization, and Integrated Discovery online bioinformatics tool. The protein-protein interaction (PPI) network was constructed by the Search Tool for the Retrieval of Interacting Genes database and hub genes were visualized by Cytoscape. Survival analysis and RNA sequencing expression were conducted by UALCAN and Gene Expression Profiling Interactive Analysis.A total of 115 shared DEGs were identified, including 30 upregulated genes and 85 downregulated genes in HCC samples. P53 signaling pathway and cell cycle were the major enriched pathways for the upregulated DEGs whereas metabolism-related pathways were the major enriched pathways for the downregulated DEGs. The PPI network was established with 105 nodes and 249 edges and 3 significant modules were identified via molecular complex detection. Additionally, 17 candidate genes from these 3 modules were significantly correlated with HCC patient survival and 15 of 17 genes exhibited high expression level in HCC samples. Moreover, 4 hub genes (CCNB1, CDK1, RRM2, BUB1B) were identified for further reanalysis of KEGG pathway, and enriched in 2 pathways, the P53 signaling pathway and cell cycle pathway.Overexpression of CCNB1, CDK1, RRM2, and BUB1B in HCC samples was correlated with poor survival in HCC patients, which could be potential therapeutic targets for HCC.

Glucose Metabolism and Oxidative Stress in Hepatocellular Carcinoma: Role and Possible Implications in Novel Therapeutic Strategies

Hepatocellular carcinoma (HCC) metabolism is redirected to glycolysis to enhance the production of metabolic compounds employed by cancer cells to produce proteins, lipids, and nucleotides in order to maintain a high proliferative rate. This mechanism drives towards uncontrolled growth and causes a further increase in reactive oxygen species (ROS), which could lead to cell death. HCC overcomes the problem generated by ROS increase by increasing the antioxidant machinery, in which key mechanisms involve glutathione, nuclear factor erythroid 2-related factor 2 (Nrf2), and hypoxia-inducible transcription factor (HIF-1α). These mechanisms could represent optimal targets for innovative therapies. The tumor microenvironment (TME) exerts a key role in HCC pathogenesis and progression. Various metabolic machineries modulate the activity of immune cells in the TME. The deregulated metabolic activity of tumor cells could impair antitumor response. Lactic acid-lactate, derived from the anaerobic glycolytic rate of tumor cells, as well as adenosine, derived from the catabolism of ATP, have an immunosuppressive activity. Metabolic reprogramming of the TME via targeted therapies could enhance the treatment efficacy of anti-cancer immunotherapy. This review describes the metabolic pathways mainly involved in the HCC pathogenesis and progression. The potential targets for HCC treatment involved in these pathways are also discussed.

Effect of glucose deprivation on the expression of genes encoding glucocorticoid receptor and some related factors in ERN1-knockdown U87 glioma cells

OBJECTIVE

The aim of the present study was to examine the effect of glucose deprivation on the expression of genes encoded glucocorticoid receptor (NR3C1) and some related proteins (NR3C2, AHR, NRIP1, NNT, ARHGAP35, SGK1, and SGK3) in U87 glioma cells in response to inhibition of endoplasmic reticulum stress signaling mediated by ERN1/IRE1 (endoplasmic reticulum to nucleus signaling 1/inositol requiring enzyme 1) for evaluation of their possible significance in the control of glioma growth through endoplasmic reticulum stress signaling mediated by IRE1 and glucose deprivation.

METHODS

The expression of NR3C1, NR3C2, AHR, NRIP1, NNT, ARHGAP35, SGK1, and SGK3 genes in U87 glioma cells transfected by empty vector pcDNA3.1 (control cells) and cells without ERN1 signaling enzyme function (transfected by dnERN1) under glucose deprivation was studied by real time quantitative polymerase chain reaction.

RESULTS

It was shown that the expression level of NR3C2, AHR, SGK1, SGK3, and NNT genes was up-regulated in control U87 glioma cells under glucose deprivation condition in comparison with the control cells growing with glucose. At the same time, the expression of NRIP1 gene is down-regulated in these glioma cells under glucose deprivation, but NR3C1 and ARHGAP35 genes was resistant to this experimental condition. We also showed that inhibition of ERN1 signaling enzyme function significantly modified the response of most studied gene expressions to glucose deprivation condition. Thus, effect of glucose deprivation on the expression level of NR3C2, AHR, and SGK1 genes was significantly stronger in ERN1 knockdown U87 glioma cells since the expression of NNT gene was resistant to glucose deprivation condition. Moreover, the inhibition of ERN1 enzymatic activities in U87 glioma cells led to up-regulation of ARHGAP35 gene expression and significant down-regulation of the expression of SGK3 gene in response to glucose deprivation condition.

CONCLUSIONS

Results of this study demonstrated that glucose deprivation did not change the expression level of NR3C1 gene but it significantly affected the expression of NR3C2, AHR, NRIP, SGK1, SGK3, and NNT genes in vector-transfected U87 glioma cells in gene specific manner and possibly contributed to the control of glioma growth since the expression of most studied genes in glucose deprivation condition was significantly dependent on the functional activity of IRE1 signaling enzyme.

CDK1, CCNB1, CDC20, BUB1, MAD2L1, MCM3, BUB1B, MCM2, and RFC4 May Be Potential Therapeutic Targets for Hepatocellular Carcinoma Using Integrated Bioinformatic Analysis

Hepatocellular carcinoma (HCC) is a malignant tumor with high mortality. The abnormal expression of genes is significantly related to the occurrence of HCC. The aim of this study was to explore the differentially expressed genes (DEGs) of HCC and to provide bioinformatics basis for the occurrence, prevention and treatment of HCC. The DEGs of HCC and normal tissues in GSE102079, GSE121248, GSE84402 and GSE60502 were obtained using R language. The GO function analysis and KEGG pathway enrichment analysis of DEGs were carried out using the DAVID database. Then, the protein–protein interaction (PPI) network was constructed using the STRING database. Hub genes were screened using Cytoscape software and verified using the GEPIA, UALCAN, and Oncomine database. We used HPA database to exhibit the differences in protein level of hub genes and used LinkedOmics to reveal the relationship between candidate genes and tumor clinical features. Finally, we obtained transcription factor (TF) of hub genes using NetworkAnalyst online tool. A total of 591 overlapping up-regulated genes were identified. These genes were related to cell cycle, DNA replication, pyrimidine metabolism, and p53 signaling pathway. Additionally, the GEPIA database showed that the CDK1, CCNB1, CDC20, BUB1, MAD2L1, MCM3, BUB1B, MCM2, and RFC4 were associated with the poor survival of HCC patients. UALCAN, Oncomine, and HPA databases and qRT-PCR confirmed that these genes were highly expressed in HCC tissues. LinkedOmics database indicated these genes were correlated with overall survival, pathologic stage, pathology T stage, race, and the age of onset. TF analysis showed that MYBL2, KDM5B, MYC, SOX2, and E2F4 were regulators to these nine hub genes. Overexpression of CDK1, CCNB1, CDC20, BUB1, MAD2L1, MCM3, BUB1B, MCM2, and RFC4 in tumor tissues predicted poor survival in HCC. They may be potential therapeutic targets for HCC.

Experimental Models to Define the Genetic Predisposition to Liver Cancer

Hepatocellular carcinoma (HCC) is a frequent human cancer and the most frequent liver tumor. The study of genetic mechanisms of the inherited predisposition to HCC, implicating gene-gene and gene-environment interaction, led to the discovery of multiple gene loci regulating the growth and multiplicity of liver preneoplastic and neoplastic lesions, thus uncovering the action of multiple genes and epistatic interactions in the regulation of the individual susceptibility to HCC. The comparative evaluation of the molecular pathways involved in HCC development in mouse and rat strains differently predisposed to HCC indicates that the genes responsible for HCC susceptibility control the amplification and/or overexpression of c-Myc, the expression of cell cycle regulatory genes, and the activity of Ras/Erk, AKT/mTOR, and of the pro-apoptotic Rassf1A/Nore1A and Dab2IP/Ask1 pathways, the methionine cycle, and DNA repair pathways in mice and rats. Comparative functional genetic studies, in rats and mice differently susceptible to HCC, showed that preneoplastic and neoplastic lesions of resistant mouse and rat strains cluster with human HCC with better prognosis, while the lesions of susceptible mouse and rats cluster with HCC with poorer prognosis, confirming the validity of the studies on the influence of the genetic predisposition to hepatocarinogenesis on HCC prognosis in mouse and rat models. Recently, the hydrodynamic gene transfection in mice provided new opportunities for the recognition of genes implicated in the molecular mechanisms involved in HCC pathogenesis and prognosis. This method appears to be highly promising to further study the genetic background of the predisposition to this cancer.