Docking and molecular dynamic simulations of Mithramycin-A and Tolfenamic acid against Sp1 and survivin.

Therapeutic targeting of Sp1 transcription factor and survivin, are studied in various cancers due to their consistent overexpression. These markers result in poorer cancer prognoses and their downregulation has been investigated as an effective treatment approach. Mithramycin-A and Tolfenamic acid are two drugs with innate anti-cancer properties and are suggested to be able to target Sp1 through GC/GT DNA binding interference, however in-depth binding and mechanistic studies are lacking. Through docking analysis, we investigated Mithramycin-A and Tolfenamic acid in terms of their specific binding interactions with Sp1 and survivin. Through further molecular dynamics simulations including Root Mean Square (RMS) Fluctuation and RMS Deviation, rGYr, and H-bond analysis, we identified critical residues involved in drug interactions with each protein in question. We show Mithramycin-A as the superior binding candidate to each protein and found that it exhibited stronger binding with Sp1, and then survivin. Subsequent molecular dynamics simulations followed the same trend as initial binding energy calculations and showed crucial amino acids involved in each Mithramycin-A-protein complex. Our findings warrant further investigation into Mithramycin-A and its specific interaction with Sp1 and their downstream targets giving a better understanding of Mithramycin-A and its potential as an effective cancer treatment.

SP1­mediated ADAMTS5 transcription promotes IL­1ß­induced chondrocyte injury via Wnt/ß­catenin pathway in osteoarthritis.

Osteoarthritis (OA) is a chronic disease that involves chondrocyte injury. ADAMTS5 has been confirmed to mediate chondrocyte injury and thus regulate OA progression, but its underlying molecular mechanisms remain unclear. In the present study, interleukin­1ß (IL­1ß)­induced chondrocytes were used to mimic OA in vitro. Cell proliferation and apoptosis were assessed by MTT assay, EdU assay and flow cytometry, and protein levels of ADAMTS5, specificity protein 1 (SP1), matrix­related markers and Wnt/ß­catenin pathway­related markers were examined using western blotting. In addition, ELISA was performed to measure the concentrations of inflammation factors, and oxidative stress was evaluated by detecting SOD activity and MDA levels. The mRNA expression levels of ADAMTS5 and SP1 were determined by reverse transcription­quantitative PCR, and the interaction between SP1 and ADAMTS5 was analyzed using a dual­luciferase reporter assay and chromatin immunoprecipitation assay. IL­1ß suppressed proliferation, but promoted apoptosis, extracellular matrix degradation, inflammation and oxidative stress in chondrocytes. ADAMTS5 was upregulated in IL­1ß­induced chondrocytes, and its knockdown alleviated IL­1ß­induced chondrocyte injury. SP1 could bind to the ADAMTS5 promoter region to promote its transcription, and SP1 knockdown relieved IL­1ß­induced chondrocyte injury by reducing ADAMTS5 expression. The SP1/ADAMTS5 axis activated the Wnt/ß­catenin pathway, and the Wnt/ß­catenin pathway agonist, SKL2001, reversed the protective effect of ADAMTS5 knockdown on chondrocyte injury induced by IL­1ß. To the best of our knowledge, the present study was the first to reveal the interaction between SP1 and ADAMTS5 in OA progression and indicated that the SP1/ADAMTS5 axis mediates OA progression by regulating the Wnt/ß­catenin pathway.

Specificity protein 1/3 regulate T-cell acute lymphoblastic leukemia cell proliferation and apoptosis through ß-catenin by acting as targets of miR-495-3p.

T-cell acute lymphoblastic leukemia (T-ALL) is a hematologic heterogeneous disease. This study explored the mechanism of specificity protein 1/3 (Sp1/3) in T-ALL cells through ß-catenin by acting as targets of miR-495-3p. Expression levels of miR-495-3p, Sp1, Sp3, and ß-catenin in the serum from T-ALL children patients, healthy controls, and the T-ALL cell lines were measured. The cell proliferation ability and apoptosis rate were detected. Levels of proliferation-related proteins proliferating cell nuclear antigen (PCNA)/cyclinD1 and apoptosis-related proteins B-cell lymphoma-2 associated X protein (Bax)/B-cell lymphoma-2 (Bcl-2) were determined. The binding of Sp1/3 and ß-catenin promoter and the targeted relationship between miR-495-3p with Sp1/3 were analyzed. Sp1/3 were upregulated in CD4+ T-cells in T-ALL and were linked with leukocyte count and risk classification. Sp1/3 interference prevented proliferation and promoted apoptosis in T-ALL cells. Sp1/3 transcription factors activated ß-catenin expression. Sp1/3 enhanced T-ALL cell proliferation by facilitating ß-catenin expression. miR-495-3p targeted and repressed Sp1/3 expressions. miR-495-3p overexpression inhibited T-ALL cell proliferation and promoted apoptosis. Conjointly, Sp1/3, as targets of miR-495-3p limit apoptosis and promote proliferation in T-ALL cells by promoting ß-catenin expression.

Exposure to nickel chloride induces epigenetic modification on detoxification enzyme glutathione S-transferase M2.

Nickel (Ni) is a human carcinogen with genotoxic and epigenotoxic effects. Environmental and occupational exposure to Ni increases the risk of cancer and chronic inflammatory diseases. Our previous findings indicate that Ni alters gene expression through epigenetic regulation, specifically impacting E-cadherin and angiopoietin-like 4 (ANGPTL4), involved in epithelial-mesenchymal transition and migration. GST-M2, a member of the glutathione S-transferase (GST) enzyme family, plays a crucial role in cellular defense against oxidative damage and has been increasingly associated with cancer. GST-M2 overexpression inhibits lung cancer invasion and metastasis in vitro and in vivo. Hypermethylation of its promoter in cancer cells reduces gene expression, correlating with poor prognosis in non-small-cell lung cancer patients. The impact of Ni on GST-M2 remains unclear. We will investigate whether nickel exerts regulatory effects on GST-M2 through epigenetic modifications. Additionally, metformin, an antidiabetic drug, is being studied as a chemopreventive agent against nickel-induced damage. Our findings indicate that nickel chloride (NiCl2 ) exposure, both short-term and long-term, represses GST-M2 expression. However, the expression can be restored by demethylation agent 5-aza-2'-deoxycytidine and metformin. NiCl2 promotes hypermethylation of the GST-M2 promoter, as confirmed by methylation-specific PCR and bisulfite sequencing. Additionally, NiCl2 also influences histone acetylation, and metformin counteracts the suppressive effect of NiCl2 on histone H3 expression. Metformin reestablishes the binding of specificity protein 1 to the GST-M2 promoter, which is otherwise disrupted by NiCl2 . These findings elucidate the mechanism by which Ni reduces GST-M2 expression and transcriptional activity, potentially contributing to Ni-induced lung carcinogenesis.

Inhibition of cisplatin-induced Acsl4-mediated ferroptosis alleviated ovarian injury.

Given that the severity of the chemotherapy-induced ovarian damage, effective fertility preservation is a necessary part of the treatment process. Ferroptosis is a regulated cell death triggered by excessive phospholipid peroxidation caused by iron and the role of ferroptosis in chemotherapy-induced ovarian damage remains unclear. In this study, we demonstrated that cisplatin treatment caused the accumulation of iron ions which induced ferroptosis in ovarian tissue. And our results show that ferrostatin-1 was able to suppress the ovarian injury and granulosa cell death caused by cisplatin (Cis) in vivo and in vitro. At the same time, we observed significant changes in the expression levels of Acyl-CoA synthetase long-chain family member 4 (Acsl4) and glutathione peroxidase 4 (GPX4). Similarly, Rosiglitazone, an inhibitor of Acsl4, administration alleviated the ovary damage of the mice undergoing chemotherapy. Further mechanistic investigation showed that cisplatin increased the expression level of specificity protein 1 (SP1), and SP1 could bind to the promoter of Acsl4 to increased Acsl4 transcription. Overall, ferroptosis plays an important role in Cis induced ovarian injury, and inhibition of ferroptosis protects ovarian tissues from damage caused by cisplatin, and for the first time, we have identified the potential of Fer-1 and Rosi to protect ovarian function in female mice undergoing chemotherapy.

KLF6 activates Sp1-mediated prolidase transcription during TGF-ß1 signaling.

Prolidase (PEPD) is the only hydrolase that cleaves the dipeptides containing C-terminal proline or hydroxyproline-the rate-limiting step in collagen biosynthesis. However, the molecular regulation of prolidase expression remains largely unknown. In this study, we have identified overlapping binding sites for the transcription factors Krüppel-like factor 6 (KLF6) and Specificity protein 1 (Sp1) in the PEPD promoter and demonstrate that KLF6/Sp1 transcriptionally regulate prolidase expression. By cloning the PEPD promoter into a luciferase reporter and through site-directed deletion, we pinpointed the minimal sequences required for KLF6 and Sp1-mediated PEPD promoter-driven transcription. Interestingly, Sp1 inhibition abrogated KLF6-mediated PEPD promoter activity, suggesting that Sp1 is required for the basal expression of prolidase. We further studied the regulation of PEPD by KLF6 and Sp1 during transforming growth factor ß1 (TGF-ß1) signaling, since both KLF6 and Sp1 are key players in TGF-ß1 mediated collagen biosynthesis. Mouse and human fibroblasts exposed to TGF-ß1 resulted in the induction of PEPD transcription and prolidase expression. Inhibition of TGF-ß1 signaling abrogated PEPD promoter-driven transcriptional activity of KLF6 and Sp1. Knock-down of KLF6 as well as Sp1 inhibition also reduced prolidase expression. Chromatin immunoprecipitation assay supported direct binding of KLF6 and Sp1 to the PEPD promoter and this binding was enriched by TGF-ß1 treatment. Finally, immunofluorescence studies showed that KLF6 co-operates with Sp1 in the nucleus to activate prolidase expression and enhance collagen biosynthesis. Collectively, our results identify functional elements of the PEPD promoter for KLF6 and Sp1-mediated transcriptional activation and describe the molecular mechanism of prolidase expression.

Evening Primrose Extract Modulates TYMS Expression via SP1 Transcription Factor in Malignant Pleural Mesothelioma.

PURPOSE: To determine the mechanism of EPE in downregulating TYMS in MPM cancer. METHODS: The TYMS mRNA expression with epithelial-to-mesenchymal transition biomarkers and nuclear factor SP1 was assessed using the GEO database in a data set of MPM patients (GSE51024). Invasive MPM cell lines were in vitro models for the investigation of TYMS expression after EPE treatment. The tyms promoter SP1 binding sequences were determined using Genomatix v 3.4 software Electrophoretic mobility shift and dual-luciferase reporter assays revealed specific SP1 motifs in the interaction of EPE and reference compounds. Chromatin immunoprecipitation and Re-ChIP were used for the co-occupancy study. RESULTS: In MPM patients, a positive correlation of overexpressed TYMS with mesenchymal TWIST1, FN1 and N-cadherin was observed. EPE and its major components, gallic and ellagic acid (GA and EA, respectively), downregulated TYMS in invasive MPM cells by interacting with particular SP1 motifs on the tyms promoter. The luciferase constructs confirmed the occupation of two SP1 regulatory regions critical for the promotion of TYMS expression. Both EPE and reference standards influenced SP1 translocation into the nucleus. CONCLUSION: EPE components reduced TYMS expression by occupation of SP1 motifs on the tyms promoter and reversed the EMT phenotype of invasive MPM cells. Further in-depth analysis of the molecular docking of polyphenol compounds with SP1 regulatory motifs is required.

N-terminal domain of classical swine fever virus Npro induces proteasomal degradation of specificity protein 1 with reduced HDAC1 expression to evade from innate immune responses.

IMPORTANCE: Of the flaviviruses, only CSFV and bovine viral diarrhea virus express Npro as the non-structural protein which is not essential for viral replication but functions to dampen host innate immunity. We have deciphered a novel mechanism with which CSFV uses to evade the host antiviral immunity by the N-terminal domain of its Npro to facilitate proteasomal degradation of Sp1 with subsequent reduction of HDAC1 and ISG15 expression. This is distinct from earlier findings involving Npro-mediated IRF3 degradation via the C-terminal domain. This study provides insights for further studies on how HDAC1 plays its role in antiviral immunity, and if and how other viral proteins, such as the core protein of CSFV, the nucleocapsid protein of porcine epidemic diarrhea virus, or even other coronaviruses, exert antiviral immune responses via the Sp1-HDAC1 axis. Such research may lead to a deeper understanding of viral immune evasion strategies as part of their pathogenetic mechanisms.

Sp1 promotes tumour progression by remodelling the mitochondrial network in cervical cancer.

BACKGROUND: Cervical cancer remains one of the most prevalent cancers worldwide. Accumulating evidence suggests that specificity protein 1 (Sp1) plays a pivotal role in tumour progression. The underlying role and mechanism of Sp1 in tumour progression remain unclear. METHODS: The protein level of Sp1 in tumour tissues was determined by immunohistochemistry. The effect of Sp1 expression on the biological characteristics of cervical cancer cells was assessed by colony, wound healing, transwell formation, EdU, and TUNEL assays. Finally, the underlying mechanisms and effects of Sp1 on the mitochondrial network and metabolism of cervical cancer were analysed both in vitro and in vivo. RESULTS: Sp1 expression was upregulated in cervical cancer. Sp1 knockdown suppressed cell proliferation both in vitro and in vivo, while overexpression of Sp1 had the opposite effects. Mechanistically, Sp1 facilitated mitochondrial remodelling by regulating mitofusin 1/2 (Mfn1/2), OPA1 mitochondrial dynamin-like GTPase (Opa1), and dynamin 1-like (Drp1). Additionally, the Sp1-mediated reprogramming of glucose metabolism played a critical role in the progression of cervical cancer cells. CONCLUSIONS: Our study demonstrates that Sp1 plays a vital role in cervical tumorigenesis by regulating the mitochondrial network and reprogramming glucose metabolism. Targeting Sp1 could be an effective strategy for the treatment of cervical cancer.

Regulation of USP25 by SP1 Associates with Amyloidogenesis.

BACKGROUND: Trisomy 21, an extra copy of human chromosome 21 (HSA21), causes most Down's syndrome (DS) cases. Individuals with DS inevitably develop Alzheimer's disease (AD) neuropathological phenotypes after middle age including amyloid plaques and tau neurofibrillary tangles. Ubiquitin Specific Peptidase 25 (USP25), encoding by USP25 gene located on HSA21, is a deubiquitinating enzyme, which plays an important role in both DS and AD pathogenesis. However, the regulation of USP25 remains unclear. OBJECTIVE: We aimed to determine the regulation of USP25 by specificity protein 1 (SP1) in neuronal cells and its potential role in amyloidogenesis. METHODS: The transcription start site and promoter activity was identified by SMART-RACE and Dual-luciferase assay. Functional SP1-responsive elements were examined by EMSA. USP25 expression was examined by RT-PCR and immunoblotting. Student's t-test or one-way ANOVA were applied or statistical analysis. RESULTS: The transcription start site of human USP25 gene was identified. Three functional SP1 responsive elements in human USP25 gene were revealed. SP1 promotes USP25 transcription and subsequent USP25 protein expression, while SP1 inhibition significantly reduces USP25 expression in both non-neuronal and neuronal cells. Moreover, SP1 inhibition dramatically reduces amyloidogenesis. CONCLUSION: We demonstrates that transcription factor SP1 regulates USP25 gene expression, which associates with amyloidogenesis. It suggests that SP1 signaling may play an important role in USP25 regulation and contribute to USP25-mediated DS and AD pathogenesis.

GATA-binding protein 4 promotes neuroinflammation and cognitive impairment in Aß1-42 fibril-infused rats through small nucleolar RNA host gene 1/miR-361-3p axis.

Aging with dysregulated metabolic and immune homeostasis stimulates pyroptosis, neuroinflammation, and cellular senescence, thus contributing to etiopathogenesis of Alzheimer's disease. GATA-binding protein 4 (GATA4) functions as a transcriptional factor in response to DNA damage, and is associated with neuroinflammation and cellular senescence. The role of GATA4 in Alzheimer's disease was investigated. GATA4 was elevated in hippocampus of Aß1-42 fibril-infused rats. Injection with shRNA targeting GATA4 reduced escape latency with increase of time in target quadrant and number of platform crossings in Aß1-42 fibril-infused rats. Moreover, knockdown of GATA4 ameliorated morphological changes of hippocampus and reduced amyloid plaque deposition in Aß1-42 fibril-infused rats. Silence of GATA4 repressed neuroinflammation and apoptosis in Aß1-42 fibril-infused rats. Loss of GATA4 in Aß1-42 fibril-infused rats reduced the expression of specificity protein 1 (Sp1) to downregulate long noncoding RNA small nucleolar RNA host gene 1 (SNHG1) and upregulated miR-361-3p. Loss of SNHG1 ameliorated learning and memory impairments in Aß1-42 fibril-infused rats. Overexpression of Sp1 attenuated GATA4 silence-induced decrease of escape latency, increase of time in target quadrant, and number of platform crossings in Aß1-42 fibril-infused rats. In conclusion, silence of GATA4 ameliorated cognitive dysfunction and inhibited hippocampal inflammation and cell apoptosis through regulation of Sp1/SNHG1/miR-361-3p.

UCHL1 regulated by Sp1 ameliorates cochlear hair cell senescence and oxidative damage.

Age-related hearing loss (ARHL) is the most common cause of hearing loss in the elderly. Ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) is a deubiquitinating enzyme involved in several types of human disease. The present study aimed to investigate the effect of UCHL1 on a hydrogen peroxide (H2O2)-induced ARHL model in cochlear hair cells and uncover its underlying mechanism. Reverse transcription-quantitative (RT-q)PCR and western blot analysis were used to assess UCHL1 expression in HEI-OC1 cells exposed to H2O2. Following UCHL1 overexpression in H2O2-induced HEI-OC1 cells, cell activity was assessed by Cell Counting Kit-8 assay. The content of oxidative stress-associated markers including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and reactive oxygen species (ROS ) was measured using corresponding commercial kits. Cell apoptosis was evaluated by TUNEL assay and western blot analysis. Cell senescence was assessed by senescence-associated ß-galactosidase staining and western blot analysis. RT-qPCR and western blot analysis were applied to measure mRNA and protein expression levels, respectively, of specificity protein 1 (Sp1) in H2O2-treated HEI-OC1 cells. In addition, the association between UCHL1 and Sp1 was verified by luciferase reporter and chromatin immunoprecipitation (ChIP) assay. The mRNA and protein expression levels of UCHL1 were also determined in Sp1-overexpressing cells by RT-qPCR and western blot analysis, respectively. Following Sp1 overexpression in UCHL1-overexpressing H2O2-treated HEI-OC1 cells, cell activity, oxidative stress, apoptosis and senescence were assessed. Finally, the expression levels of NF-κB signaling-related proteins p-NF-κB p65 and NF-κB p65 were detected using western blot analysis. The results showed that UCHL1 was downregulated in H2O2-treated HEI-OC1 cells. In addition, UCHL1 overexpression enhanced cell viability and promoted oxidative damage, apoptosis and senescence in H2O2-induced HEI-OC1 cells. Furthermore, Sp1 was upregulated in H2O2-treated HEI-OC1 cells. Additionally, luciferase reporter and ChIP assays demonstrated that Sp1 interacted with the UCHL1 promoter to inhibit UCHL1 transcription. Sp1 overexpression reversed the effect of UCHL1 overexpression on cell viability, oxidative stress, apoptosis, senescence and activation of the NF-κB signaling pathway in H2O2-exposed HEI-OC1 cells. Collectively, the results suggested that UCHL1 transcriptional suppression by Sp1 protected cochlear hair cells from H2O2-triggered senescence and oxidative damage.

Sevoflurane Postconditioning Attenuates Cerebral Ischemia-Reperfusion Injury by Inhibiting SP1/ACSL4-Mediated Ferroptosis.

Sevoflurane is the most commonly used anesthetic in clinical practice and exerts a protective effect on cerebral ischemia-reperfusion (I/R) injury. This study aims to elucidate the molecular mechanism by which sevoflurane postconditioning protects against cerebral I/R injury. Oxygen-glucose deprivation/reperfusion (OGD/R) model in vitro and the middle cerebral artery occlusion (MCAO) model in vivo were established to simulate cerebral I/R injury. Sevoflurane postconditioning reduced neurological deficits, cerebral infarction, and ferroptosis after I/R injury. Interestingly, sevoflurane significantly inhibited specificity protein 1 (SP1) expression in MACO rats and HT22 cells exposed to OGD/R. SP1 overexpression attenuated the neuroprotective effects of sevoflurane on OGD/R-treated HT22 cells, evidenced by reduced cell viability, increased apoptosis, and cleaved caspase-3 expression. Furthermore, chromatin immunoprecipitation and luciferase experiments verified that SP1 bound directly to the ACSL4 promoter region to increase its expression. In addition, sevoflurane inhibited ferroptosis via SP1/ACSL4 axis. Generally, our study describes an anti-ferroptosis effect of sevoflurane against cerebral I/R injury via downregulating the SP1/ASCL4 axis. These findings suggest a novel sight for cerebral protection against cerebral I/R injury and indicate a potential therapeutic approach for a variety of cerebral diseases.

Mechanism of Transcription Factor SP1 Regulates Expression of Tripartite Motif-containing Protein 7 in Hepatocellular Carcinoma / 中国生物化学与分子生物学报

Tripartite motif containing protein 7 (TRIM7), as a member of the E3 ubiquitin ligase TRIM family, plays an important regulatory role in immune regulation, metabolism and other physiological processes. The aberrant expression of TRIM7 is closely related to the development and progression of hepatocellular carcinoma (HCC) and it shows a complex regulatory role. However, the regulatory mechanism for the expression of TRIM7 in HCC remains unknown. In this study, multiple online databases were used to analyze the expression of TRIM7 in HCC and data indicated that TRIM7 expression was upregulated in HCC and correlated to poor prognosis. Subsequently, the transcription factor binding sites in the TRIM7 promoter region were analyzed using UCSC and JASPAR databases, and the results showed that TRIM7 promoter contains four SP1 binding sites. In this work, we demonstrated that SP1 could directly bind to its binding sites in TRIM7 promoter and positively regulate the transcriptional activity driven by the TRIM7 promoter using dual luciferase reporter experiments and the ChIP-PCR method. Moreover, our results also showed SP1 overexpression upregulated the expression of TRIM7 at both mRNA and protein levels (P<0. 01),and SP1 inhibitor, mithramycin A, could reverse the activated effect of SP1 on TRIM7 expression (P<0. 01). In conclusion, this study preliminarily reveals the regulatory mechanism of TRIM7 upregulation in HCC, which provides an important theoretical basis for further study of the gene function, early diagnosis and targeted therapy.

Natural carbazole alkaloid murrayafoline A displays potent anti-neuroinflammatory effect by directly targeting transcription factor Sp1 in LPS-induced microglial cells.

Neuroinflammation is a leading cause for neurological disorders. Carbazole alkaloids, isolated from the medicinal plants of Murraya species (Rutaceae), have exhibited wide pharmacological activities particularly for neuroinflammation. However, its underlying cellular targets and molecular mechanisms still remain unclear. In current study, we found that murrayafoline A (MA), a carbazole alkaloid obtained from Murraya tetramera, potently inhibited the production of neuroinflammation mediators, such as nitric oxide (NO), TNF-α, IL-6 and IL-1ß in LPS-induced BV-2 microglial cells. Then, we performed thermal proteome profiling (TPP) strategy to identify Specificity protein 1 (Sp1) as a potential cellular target of MA. Moreover, we performed surface plasmon resonance (SPR), cellular thermal shift assay (CETSA) and drug affinity responsive target stability (DRATS) assays to confirm the direct interaction between MA and Sp1. Furthermore, we downregulated Sp1 expression in BV2 cells using siRNA transfection, and observed that Sp1 knockdown significantly antagonized MA-mediated inhibition of neuroinflammation mediator production. Meanwhile, Sp1 knockdown also markedly reversed MA-mediated inactivation of IKKß/NF-κB and p38/JNK MAPKs pathways. Finally, in vivo studies revealed that MA significantly suppressed the expression of Iba-1, TNF-α, and IL-6, while increased the number of Nissl bodies in the brains of LPS-induced mice. Taken together, our study demonstrated that MA exerted obvious anti-neuroinflammation effect by directly targeting Sp1, thereby inhibiting NF-κB and MAPK signaling pathways. Our findings also provided a promising direction of pharmacological targeting Sp1 for anti-neuroinflammation therapeutics as well as novel agent development.

Transcription factor SP1 regulates haptoglobin fucosylation via induction of GDP-fucose transporter 1 in the hepatoma cell line HepG2.

Fucosylation is involved in cancer and inflammation, and several fucosylated proteins, such as AFP-L3 for hepatocellular carcinoma, are used as cancer biomarkers. We previously reported an increase in serum fucosylated haptoglobin (Fuc-Hp) as a biomarker for several cancers, including pancreatic and colon cancer and hepatocellular carcinoma. The regulation of fucosylated protein production is a complex cellular process involving various fucosylation regulatory genes. In this report, we investigated the molecular mechanisms regulating Fuc-Hp production in cytokine-treated hepatoma cells using a partial least squares (PLS) regression model. We found that SLC35C1, which encodes GDP-fucose transporter 1 (GFT1), is the most responsible factor for Fuc-Hp production among various fucosylation regulatory genes. Furthermore, the transcription factor SP1 was essential in regulating SLC35C1 expression. We also found that an SP1 inhibitor was able to suppress Fuc-Hp production without affecting total Hp levels. Taken together, Fuc-Hp production was regulated by SP1 via induction of GFT1 in the hepatoma cell line HepG2.

The miR-548d-5p/SP1 signaling axis regulates chondrocyte proliferation and inflammatory responses in osteoarthritis.

Chondrocyte apoptosis and dysfunction play an important role in osteoarthritis (OA), a chronic progressive arthropathy. Non-coding RNAs have been implicated in OA pathogenesis. In this study, microRNA (miR)-548d-5p was found to be downregulated in OA samples and IL-1ß-stimulated chondrocytes. miR-548d-5p overexpression partially reversed IL-1ß-induced chondrocyte damage in vitro, evidenced by the promotion of cell growth, the inhibition of apoptosis and inflammatory cytokine release, and the improvement in extracellular matrix (ECM) deposition. Furthermore, miR-548d-5p overexpression partially reversed papain-induced damages on OA rat's knee articular cartilage. Specificity protein 1 (SP1) was inhibited by miR-548d-5p and identified as its direct downstream target. In IL-1ß-stimulated chondrocytes, SP1 overexpression significantly attenuated the protective effects of miR-548d-5p overexpression against chondrocyte damage. In conclusion, miR-548d-5p was abnormally downregulated in OA samples and IL-1ß-stimulated chondrocytes. miR-548d-5p protects against IL-1ß-induced chondrocyte damage via direct inhibition of SP1.

SP1 Promotes HDAC4 Expression and Inhibits HMGB1 Expression to Reduce Intestinal Barrier Dysfunction, Oxidative Stress, and Inflammatory Response after Sepsis.

As a serious and elusive syndrome caused by infection, sepsis causes a high rate of mortality around the world. Our investigation aims at exploring the role and possible mechanism of specificity protein-1 (SP1) in the development of sepsis. A mouse model of sepsis was established by cecal ligation perforation, and a cellular model was stimulated by lipopolysaccharide (LPS), followed by determination of the SP1 expression. It was determined that SP1 was poorly expressed in the intestinal tissues of septic mice and LPS-treated cells. Next, we examined the interactions among SP1, histone deacetylase 4 (HDAC4), and high mobility group box 1 (HMGB1) and found that SP1 bound to the HDAC4 promoter to upregulate its expression, thereby promoting the deacetylation of HMGB1. Meanwhile, gain- or loss-of-function approaches were applied to evaluate the intestinal barrier dysfunction, oxidative stress, and inflammatory response. Overexpression of SP1 or underexpression of HMGB1 was observed to reduce intestinal barrier dysfunction, oxidative stress, and inflammatory injury. Collectively, these experimental data provide evidence reporting that SP1 could promote the HDAC4-mediated HMGB1 deacetylation to reduce intestinal barrier dysfunction, oxidative stress, and inflammatory response induced by sepsis, providing a novel therapeutic target for sepsis prevention and treatment.

Sodium selenite promotes neurological function recovery after spinal cord injury by inhibiting ferroptosis.

Ferroptosis is a recently discovered form of iron-dependent cell death, which occurs during the pathological process of various central nervous system diseases or injuries, including secondary spinal cord injury. Selenium has been shown to promote neurological function recovery after cerebral hemorrhage by inhibiting ferroptosis. However, whether selenium can promote neurological function recovery after spinal cord injury as well as the underlying mechanism remain poorly understood. In this study, we injected sodium selenite (3 µL, 2.5 µM) into the injury site of a rat model of T10 vertebral contusion injury 10 minutes after spinal cord injury modeling. We found that sodium selenite treatment greatly decreased iron concentration and levels of the lipid peroxidation products malondialdehyde and 4-hydroxynonenal. Furthermore, sodium selenite increased the protein and mRNA expression of specificity protein 1 and glutathione peroxidase 4, promoted the survival of neurons and oligodendrocytes, inhibited the proliferation of astrocytes, and promoted the recovery of locomotive function of rats with spinal cord injury. These findings suggest that sodium selenite can improve the locomotive function of rats with spinal cord injury possibly through the inhibition of ferroptosis via the specificity protein 1/glutathione peroxidase 4 pathway.

[Retracted] MicroRNA­760 inhibits cell proliferation and invasion of colorectal cancer by targeting the SP1­mediated PTEN/AKT signalling pathway.

Following the publication of this paper, it was drawn to the Editors' attention by a concerned reader that certain of the cell migration and invasion assay data shown in Figs. 2C and 5C were strikingly similar to data appearing in different form in other articles by different authors. Owing to the fact that the contentious data in the above article had already been published elsewhere, or were already under consideration for publication, prior to its submission to Molecular Medicine Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a satisfactory reply. The Editor apologizes to the readership for any inconvenience caused. [the original article was published in Molecular Medicine Reports 16: 9692­9700, 2017; DOI: 10.3892/mmr.2017.7814].