The role of tazarotene-induced gene 1 in carcinogenesis:is it a tumor suppressor gene or an oncogene?

Tazarotene-induced gene 1(TIG1)is induced by a derivative of vitamin A and is known to regulate many important biological processes and control the development of cancer.TIG1 is widely expressed in various tissues;yet in many cancer tissues,it is not expressed because of the methylation of its promoter.Additionally,the expression of TIG1 in cancer cells inhibits their growth and invasion,suggesting that TIG1 acts as a tumor suppressor gene.However,in some cancers,poor prognosis is associated with TIG1 expression,indicating its protumor growth characteristics,especially in promoting the invasion of inflammatory breast cancer cells.This review comprehensively summarizes the roles of the TIG1 gene in cancer development and details the mechanisms through which TIG1 regulates cancer development,with the aim of understanding its various roles in cancer development.

Downregulation of Astrocyte Elevated Gene-1 Expression Combined with All-Trans Retinoic Acid Inhibits Development of Vasculogenic Mimicry and Angiogenesis in Glioma

Objective This study aimed to investigate the effects of downregulating astrocyte elevated gene-1(AEG-1)expression combined with all-trans retinoic acid(ATRA)on vasculogenic mimicry(VM)formation and angiogenesis in glioma.Methods U87 glioma cells were transfected with AEG-1 shRNA lentiviral vectors(U87-siAEG-1)and incubated in a medium containing 20µmol/L ATRA.Matrigel-based tube formation assay was performed to evaluate VM formation,and the cell counting kit-8(CCK-8)assay was used to analyze the proliferation of glioma cells in vitro.Reverse transcription-quantitative polymerase chain reaction and Western blot analysis were used to investigate the mRNA and protein expression of related genes,respectively.Glioma xenograft models were generated via subcutaneous implantation of glioma cells in nude mice.Tumor-bearing mice received an intraperitoneal injection of ATRA(10 mg/kg per day).Immunohistochemistry was used to evaluate the expression of related genes and the microvessel density(MVD)in glioma xenograft models.CD34/periodic acid-Schiff double staining was performed to detect VM channels in vivo.The volume and weight of tumors were measured,and a tumor growth curve was drawn to evaluate tumor growth.Results A combination of ATRA intervention and downregulation of AEG-1 expression significantly inhibited the proliferation of glioma cells in vitro and glioma VM formation in vitro and in vivo.It also significantly decreased MVD and inhibited tumor growth.Further,the expression levels of matrix metalloproteinase(MMP)-2,MMP-9,vascular endothelial-cadherin(VE-cadherin),and vascular endothelial growth factor(VEGF)in glioma significantly decreased in vivo and in vivo.Conclusion Hence,a combinatorial approach might be effective in treating glioma through regulating MMP-2,MMP-9,VEGF,and VE-cadherin expression.

Expression of hypoxia-inducible factor 1 alpha and oligodendrocyte lineage gene-1 in cultured brain slices after oxygen-glucose deprivation

Oligodendrocyte lineage gene-1 expressed in oligodendrocytes may trigger the repair of neuronal myelin impairment, and play a crucial role in myelin repair. Hypoxia-inducible factor la, a transcription factor, is of great significance in premature infants with hypoxic-ischemic brain damage There is little evidence of direct regulatory effects of hypoxia-inducible factor le on oligodendrocyte lineage gene-l. In this study, brain slices of Sprague-Dawley rats were cultured and subjected to oxygen-glucose deprivation. Then, slices were transfected with hypoxia-inducible factor la or oligodendrocyte lineage gene-1. The expression levels of hypoxia-inducible factor la and oligodendrocyte lineage gene-1 were significantly up-regulated in rat brains prior to transfection, as detected by immunohistochemical staining. Eight hours after transfection of slices with hypoxia-inducible factor la, oligodendrocyte lineage gene-1 expression was upregulated, and reached a peak 24 hours after transfection. Oligodendrocyte lineage gene-1 transfection induced no significant differences in hypoxia-inducible factor la levels in rat brain tissues with oxygen-glucose deprivation. These experimental findings indicate that hypoxia-inducible factor la can regulate oligodendrocyte lineage gene-1 expression in hypoxic brain tissue, thus repairing the neural impairment.

Metadherin-driven promotion of cancer stem cell phenotypes and its effect on immunity in hepatocellular carcinoma

In this editorial we provide commentary on the article published by Wang et al,featured in the recent issue of the World Journal of Gastroenterology in 2024.We focus on the metadherin(MTDH),also known as astrocyte elevated gene-1 or lysine rich CEACAM1,and its effects on cancer stem cells(CSCs)and immunity in hepatocellular carcinoma(HCC).HCC is the most common primary liver cancer and one of the leading causes of cancer-related deaths worldwide.Most HCC cases develop in the context of liver cirrhosis.Among the pivotal mechanisms of carcinogenesis are gene mutations,dysregulation of diverse signaling pathways,epigenetic alterations,hepatitis B virus-induced hepatocarcinogenesis,chronic inflammation,impact of tumor microenvironment,oxidative stress.Over the years,extensive research has been conducted on the MTDH role in various tumor pathologies,such as lung,breast,ovarian,gastric,hepatocellular,colorectal,renal carcinoma,neuroblastoma,melanoma,and leukemias.Specifically,its involvement in tumor development processes including transformation,apoptosis evasion,angiogenesis,invasion,and metastasis via multiple signaling pathways.It has been demonstrated that knockdown or knockout of MTDH disrupt tumor development and metastasis.In addition,numerous reports have been carried out regarding the MTDH influence on HCC,demonstrating its role as a predictor of poor prognosis,aggressive tumor phenotypes prone to metastasis and recurrence,and exhibiting significant potential for therapy resistance.Finally,more studies finely investigated the influence of MTDH on CSCs.The CSCs are a small subpopulation of tumor cells that sharing traits with normal stem cells like self-renewal and differentiation abilities,alongside a high plasticity that alters their phenotype.Beyond their presumed role in tumor initiation,they can drive also disease relapse,metastasis,and resistance to chemo and radiotherapy.

AEG-1 participates in high glucose-induced activation of Rho kinase and epithelial-mesenchymal transition in proximal tubular epithelial cells

Objective:To prove whether astrocyte elevated gene-1(AEG-1) plays a role in high glucosestimulated Rho kinase activation and epithelial-mesenchymal transition(EMT) in human renal tubular epithelial(HK-2) cells.Methods:The protein levels of AEG-1,alpha-smooth muscle actin,E-cadherin and MYPT1 were determined by Western blot.Results:AEG-1 protein level was upregulated in HK-2 cells stimulated with high glucose.AEG-1 siRNA downregulated Rho kinase protein expression and blocked high glucose-induced EMT.Conclusions:Our results show that AEG-1 acts a key role in high glucoseinduced activation of Rho kinase and EMT in HK-2 cells.

Expression of Egr-1 in the liver of mice following hemorrhagic shock and resuscitation

Objective: To investigate the expression of early growth response gene-1(Egr-1) in the liver following hemorrhagic shock with or without resuscitation(HS or HSR). Methods: Mice were subjected to HS or HSR.Liver expression of Egr-1 mRNA was detected by Northern blotting.DNA binding activity of the Egr-1 protein in liver nuclear extracts(NE) was determined by electrophoretic mobility shift assay(EMSA).Western blot analysis was used to assess the induction of Egr-1 protein in the liver tissue,cytoplasma and NE. Results: Egr-1 mRNA was strongly expressed as early as 1 h after HS,and its level was decreased in the following 2.5 h but still higher than that in 1 h HS group.The Egr-1 DNA binding activity elevated in the liver NE of 2.5 h HS group and 2.5 h HS + 4 h R group,so did the Egr-1 protein in the liver and the liver NE of the same two groups.However,the maximal Egr-1 protein expression was found in the cytoplasma of liver following 2.5 h HS. Conclusion: Our data suggest that both Egr-1 mRNA and protein are strongly elevated and the binding activity of Egr-1 to its cognate DNA site is increased in the liver following HSR,indicating the increases of Egr-1 transcriptional and translational levels.This study provides evidence that Egr-1 gene is activated in the liver during HS and HSR.

A novel mutation of SGK-1 gene in central serous chorioretinopathy

AIM: To investigate the association of serum glucocorticoid kinase gene-1(SGK-1) DNA variants with chronic central serous chorioretinopathy(CSC).METHODS: We enrolled 32 eyes of 32 patients who were diagnosed with chronic CSC and composed 32 normal eyes as a control group. Peripheral blood was used for DNA extraction and polymerase chain reaction amplification. SGK1 gene was sequenced by using Big Dye Terminator v3.1 cycle sequencing Kit(Applied Biosystems, Foster City, CA, USA). The SGK-1 gene and its variants were investigated in CSC patient group and control group.RESULTS: We identified a new polymorphism M32 V in two person in the patient group [Minor allele frequency(MAF) =0.009] on the region of 1-60 amino acids. The rs1057293 was located in the encoder region of the SGK- 1 gene but not associated with CSC(P =0.68). An intrinsic rs1743966 is also not associated(P =0.28).CONCLUSION: The new polymorphism M32 V is located on the region of 1-60 amino acids which is necessary for localization to the mitochondria in CSC patient. This mutation is probably important for the energy metabolism and plays an important role in the cellular response to hyperosmotic stress and other stress stimuli. Both rs1057293 and rs1743966 are not associated with CSC.

Correlation of serum sLAG-3, PARP-1 and CA50 levels with oncogene expression in surgically removed lesions in patients with gastric cancer

Objective:To study the correlation of serum sLAG-3, PARP-1 and CA50 levels with oncogene expression in surgically removed lesions in patients with gastric cancer.Methods: A total of 98 patients who were diagnosed with gastric cancer in Zhouzhi County People's Hospital between June 2015 and March 2017 were selected as the gastric cancer group of the research, and 60 healthy volunteers who received physical examination during the same period were selected as control group of the research. The serum was collected from the two groups to determine sLAG-3, PARP-1 and CA50 levels;gastric cancer lesions and adjacent lesions were collected from gastric cancer group to determine the protein expression of PDCD4, RASSF1A, p16ink4a, Kiss-1, Eaf-2, CDC4, UHRF1, OCT4, Zeb-1 and c-jun.Results:Serum sLAG-3, PARP-1 and CA50 levels of gastric cancer group were significantly higher than those of control group, and the higher the TNM stage, the higher the serum sLAG-3, PARP-1 and CA50 levels;PDCD4, RASSF1A, p16ink4a, Kiss-1, Eaf-2 and CDC4 protein levels in gastric cancer lesions were significantly lower than those in adjacent lesions and negatively correlated with serum sLAG-3, PARP-1 and CA50 levels, while UHRF1, OCT4, Zeb-1 and c-jun protein levels in gastric cancer lesions were significantly higher than those in adjacent lesions and positively correlated with serum sLAG-3, PARP-1 and CA50 levels.Conclusions:The increase in serum sLAG-3, PARP-1 and CA50 levels in patients with gastric cancer is closely related to the pathological process of gastric cancer, deletion of tumor suppressor gene expression and increase of proto-oncogene expression.

Astrocyte elevated gene-1 induces breast cancer proliferation and invasion through upregulating HER2/neu expression

Background Astrocyte elevated gene-1 （AEG-1）, primarily identified as a late response gene induced by HIV-1 infection, plays multiple roles in the process of oncogenesis. This novel gene has been demonstrated to be involved in the several potent carcinogenic pathways, including PI3K/Akt pathway, nuclear factor （NF）-KB pathway, and Wnt/13-catenin pathway. Although the function of AEG-1 has been intensively investigated in recent years, the molecular mechanism underlying its oncogenic role is largely unknown. The aim of this research was to explore the potential function of AEG-1 in breast cancer development and progression. Methods AEG-1 was ectopically overexpressed in breast cancer MCF-7 cells and its biological effects on the proliferation and invasion of MCF-7 cells were studied by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） and invasion assays. The expression of HER2/neu, a crucial oncogene involving in breast cancer carcinogenesis, was also determined. Results Overexpression of the AEG-1 promoted the proliferation and invasion ability of breast cancer cells, and upregulated the expression of HER2/neu, a crucial oncogene involving in breast cancer carcinogenesis. Conclusion AEG-1 might facilitate the proliferation and invasion of breast cancer cells by upregulating HER2/neu expression, which provides a potential target for breast cancer therapy.

Lipoxin A4 Ameliorates Lipopolysaccharide-lnduced A549 Cell Injury through Upregulation of N-myc Downstream-Regulated Gene-1

Background： Lipoxin A4 （LXA4） can alleviate lipopolysaccharide （LPS）-induced acute lung injury （ALl） and acute respiratory distress syndrome through promoting epithelial sodium channel （ENaC） expression in lung epithelial cells. However, how LXA4 promote ENaC expression is still largely elusive. The present study aimed to explore genes and signaling pathway involved in regulating ENaC expression induced by LXA4. Methods： A549 cells were incubated with LPS and LXA4, or in combination, and analyzed by quantitative real-time polymerase chain reaction （qRT-PCR） of ENaC-α/γ. Candidate genes affected by LXA4 were explored by transcriptome sequencing ofA549 cells. The critical candidate gene was validated by qRT-PCR and Western blot analysis ofA549 cells treated with LPS and LXA4 at different concentrations and time intervals. LXA4 receptor （ALX） inhibitor BOC-2 was used to test induction of candidate gene by LXA4. Candidate gene siRNA was adopted to analyze its influence on A549 viability and ENaC-α expression. Phosphoinositide 3-kinase （PI3K） inhibitor LY294002 was utilized to probe whether the PI3K signaling pathway was involved in LXA4 induction of candidate gene expression. Results： The A549 cell models of ALl were constrticted and subjected to transcriptome sequencing. Among candidate genes, N-myc downstream- regulated gent- 1 （NDRG 1 ） was validated by real-time-PCR and Western blot. NDRG 1 mRNA was elevated in a dose-dependent manner of LXA4, whereas BOC-2 antagonized NDRG 1 expression induced by LXA4. NDRG I siRNA suppressed viability of LPS-treated A549 cells （treatment vs. control, 0.605± 0.063 vs. 0.878 ± 0.083, P = 0.040） and ENaC-α expression （treatment vs. control, 0.458 ± 0.038 vs. 0.711 ± 0.035, P = 0.008）. LY294002 inhibited NDRG 1 （treatment vs. control, 0.459 ± 0.023 vs. 0.726 ± 0.020, P 0.001 ） and ENaC-α （treatment vs. control, 0.236 ± 0.021 vs. 0.814 ±0.025, P 〈 0.001 ） expressions and serum- and glucocorticoid-inducible kinase I phosphorylation （treatment vs. control, 0.442± 0.024 vs. 1.046 ± 0.082, P = 0.002）, indicating the PI3K signaling pathway was involved in regulating NDRG 1 expression induced by LXA4. Conclusion： Our research uncovered a critical role of NDRG1 in LXA4 alleviation of LPS-induced A549 cell injury through mediating PI3K signaling to restore ENaC expression.

NDRG1 promotes endothelial dysfunction and hypoxia-induced pulmonary hypertension by targeting TAF15

Background:Pulmonary hypertension(PH)represents a threatening pathophysiologic state that can be induced by chronic hypoxia and is characterized by extensive vascular remodeling.However,the mechanism underlying hypoxia-induced vascular remodeling is not fully elucidated.Methods and Results:By using quantitative polymerase chain reactions,western blotting,and immunohistochemistry,we demon-strate that the expression of N-myc downstream regulated gene-1(NDRG1)is markedly increased in hypoxia-stimulated endothelial cells in a time-dependent manner as well as in human and rat endothelium lesions.To determine the role of NDRG1 in endothelial dysfunction,we performed loss-of-function studies using NDRG1 short hairpin RNAs and NDRG1 over-expression plasmids.In vitro,silencing NDRG1 attenuated proliferation,migration,and tube formation of human pulmonary artery endothelial cells(HPAECs)un-der hypoxia,while NDRG1 over-expression promoted these behaviors of HPAECs.Mechanistically,NDRG1 can directly interact with TATA-box binding protein associated factor 15(TAF15)and promote its nuclear localization.Knockdown of TAF15 abrogated the effect of NDRG1 on the proliferation,migration and tube formation capacity of HPAECs.Bioinformatics studies found that TAF15 was involved in regulating PI3K-Akt,p53,and hypoxia-inducible factor 1(HIF-1)signaling pathways,which have been proved to be PH-related pathways.In addition,vascular remodeling and right ventricular hypertrophy induced by hypoxia were markedly alleviated in NDRG1 knock-down rats compared with their wild-type littermates.Conclusions:Taken together,our results indicate that hypoxia-induced upregulation of NDRG1 contributes to endothelial dysfunction through targeting TAF15,which ultimately contributes to the development of hypoxia-induced PH.

Relationship between MDR1 polymorphism and blood concentration of cyclosporine A

Ithough renal grafts＇ survival and functioning have been improved with the introduction of cyclosporine A （CsA） into the immunosuppression treatment, its long-term results are still failing to meet treatment expectations. One of the important reasons is that the bioavailability of CsA varies largely among different patients but the use of CsA is not individualized. The human multidrug resistance gene-1 （MDR1） encodes P-glycoprotein （P-gp） that is responsible for resistance to foreign body and plays important roles in the absorption,

Inhibition of osteosarcoma growth and metastasis using a polysaccharide derivative of Amy-g-PLLD for the delivery of AEG-1 siRNA

Osteosarcoma is the most common primary malignant neoplasm of the bone in children and adolescents and has a high risk of relapse and metastasis. Of the various methods to treat osteosarcoma, the use of genetic approaches to inhibit the rapid growth of osteosarcoma while limiting tumor metastasis has presented a challenge in its implementation. Here, we successfully synthesized a polysaccharide derivative （Amy-g-PLLD） for delivery of astrocyte elevated gene-1 （AEG-1） small-interfering RNA （siRNA） （siAEG-1）, and used it for the first time to suppress osteosarcoma tumors in vitro and in vivo. Amy-g-PLLD/ siAEG-1 complexes were delivered into 143B human osteosarcoma cells with low resultant cytotoxicity. Osteosarcoma tumor proliferation and invasion were inhibited in vitro. Intratumoral injection of Amy-g-PLLD/siAEG-1 complexes markedly inhibited tumor growth and lung metastasis in 143B tumor-bearing mice. This biocompatible and effective approach employing a natural material- siRNA complex should pave the way for more genetic research in treating osteosarcoma.

Tumor immune checkpoints and their associated inhibitors

Immunological evasion is one of the defining characteristics of cancers,as the immune modification of an immune checkpoint(IC)confers immune evasion capabilities to tumor cells.Multiple ICs,such as programmed cell death protein-1(PD-1)and cytotoxic T-lymphocyte-associated antigen-4(CTLA-4),can bind to their respective receptors and reduce tumor immunity in a variety of ways,including blocking immune cell activation signals.IC blockade(ICB)therapies targeting these checkpoint molecules have demonstrated significant clinical benefits.This is because antibody-based IC inhibitors and a variety of specific small molecule inhibitors can inhibit key oncogenic signaling pathways and induce durable tumor remission in patients with a variety of cancers.Deciphering the roles and regulatory mechanisms of these IC molecules will provide crucial theoretical guidance for clinical treatment.In this review,we summarize the current knowledge on the functional and regulatory mechanisms of these IC molecules at multiple levels,including epigenetic regulation,transcriptional regulation,and post-translational modifications.In addition,we provide a summary of the medications targeting various nodes in the regulatory pathway,and highlight the potential of newly identified IC molecules,focusing on their potential implications for cancer diagnostics and immunotherapy.