Translation regulatory long non-coding RNA 1 negatively regulates cell radiosensitivity via the miR-22-3p/SP1 axis in non-small cell lung cancer.

OBJECTIVE: Non-small cell lung cancer (NSCLC) occupies 85% of lung cancer. Long non-coding RNAs (LncRNAs) can regulate the radiosensitivity of cancers. This study explored the mechanism of lncRNA TRERNA1 in the radiosensitivity of NSCLC cells. METHODS: LncRNA TRERNA1 level in NSCLC cell lines was determined. NSCLC cell radiation tolerance was measured. TRERNA1 expression was silenced or overexpressed in A549/HCC827 cells with the highest/lowest radiation tolerance, respectively. The contents of γ-H2AX and SA-ß-gal in NSCLC cells after radiation induction were detected. The targeted binding of TRERNA1 to miR-22-3p and miR-22-3p to SP1 were verified by dual-luciferase assay. SP1 expression were detected. Functional rescue experiments were implemented to confirm the roles of miR-22-3p and SP1 in the regulatory mechanism of TRERNA1. RESULTS: TRERNA1 was upregulated in NSCLC cells. TRERNA1 silencing enhanced radiosensitivity of NSCLC cells. TRERNA1 silencing elevated the contents of γ-H2AX and SA-ß-gal in A549 cells after radiation induction, while TRERNA1 overexpression showed an opposite trend in HCC827 cells. There were targeting relationships between TRERNA1 and miR-22-3p, and miR-22-3p and SP1. miR-22-3p repression or SP1 overexpression abolished the effects of TRERNA1 silencing. CONCLUSION: TRERNA1 silencing enhanced radiosensitivity of NSCLC cells via the miR-22-3p/SP1 axis. This study may offer new targets for NSCLC treatment.

Structure of a DNA G-quadruplex that Modulates SP1 Binding Sites Architecture in HIV-1 Promoter.

Nucleic acid sequences containing guanine tracts are able to form non-canonical DNA or RNA structures known as G-quadruplexes (or G4s). These structures, based on the stacking of G-tetrads, are involved in various biological processes such as gene expression regulation. Here, we investigated a G4 forming sequence, HIVpro2, derived from the HIV-1 promoter. This motif is located 60 nucleotides upstream of the proviral Transcription Starting Site (TSS) and overlaps with two SP1 transcription factor binding sites. Using NMR spectroscopy, we determined that HIVpro2 forms a hybrid type G4 structure with a core that is interrupted by a single nucleotide bulge. An additional reverse-Hoogsteen AT base pair is stacked on top of the tetrad. SP1 transcription factor is known to regulate transcription activity of many genes through the recognition of Guanine-rich duplex motifs. Here, the formation of HIVpro2 G4 may modulate SP1 binding sites architecture by competing with the formation of the canonical duplex structure. Such DNA structural switch potentially participates to the regulation of viral transcription and may also interfere with HIV-1 reactivation or viral latency.

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.

MiR-29b Downregulation by p53/Sp1 Complex Plays a Critical Role in Bleb Scar Formation After Glaucoma Filtration Surgery.

Purpose: To investigate the function and mechanism of tumor protein p53 in pathological scarring after glaucoma filtration surgery (GFS) using human Tenon's fibroblasts (HTFs) and a rabbit GFS model. Methods: The expression of p53 in bleb scarring after GFS and transforming growth factor-ß (TGF-ß)-induced HTFs (myofibroblasts [MFs]) was examined by western blot and immunochemical analysis. The interaction between p53 and specificity protein 1 (Sp1) was investigated by immunoprecipitation. The role of p53 and Sp1 in the accumulation of collagen type I alpha 1 chain (COL1A1) and the migration of MFs was evaluated by western blot, quantitative real-time polymerase chain reaction (qRT-PCR), wound healing, and Transwell assay. The regulatory mechanisms among p53/Sp1 and miR-29b were detected via qRT-PCR, western blot, luciferase reporter assay, and chromatin immunoprecipitation assay. The therapeutic effect of mithramycin A, a specific inhibitor of Sp1, on scarring formation was evaluated in a rabbit GFS model. Results: p53 was upregulated in bleb scar tissue and MFs. p53 and Sp1 form a transcription factor complex that induces the accumulation of COL1A1 and promotes the migration of MFs through downregulation of miR-29b, a known suppressor of COL1A1. The p53/Sp1 axis inhibits miR-29b expression by the direct binding promoter of the miR-29b gene. Mithramycin A treatment attenuated bleb scar formation in vivo. Conclusions: The p53/Sp1/miR-29b signaling pathway plays a critical role in bleb scar formation after GFS. This pathway could be targeted for therapeutic intervention of pathological scarring after GFS. Translational Relevance: Our research indicates that inhibition of p53/Sp1/miR-29b is a promising therapeutic strategy for preventing post-GFS pathological scarring.

Over-expression of cFos by the Transcription Factors NFATc2 and Sp1 in Pancreatic Cancer Cells.

BACKGROUND/AIM: The transcription factors NFATc2 and Sp1 play a key role in the progression of pancreatic cancer because they interact inside the cells and exert their carcinogenic effect through transcriptional modification. Drugs can also induce a variety of oncogenic signalling cascades. The risk of tumour progression and metastasis seems to be significantly increased in the perioperative period. Our research group has previously demonstrated the function of the interaction between NFATc2 and Sp1 in pancreatic cancer and has identified the proto-oncogene cFos as a target gene. We also found that the anaesthetic drug propofol has anti-tumour properties. The aim of the present study was to investigate the effect of propofol on the expression of the transcription factors NFATc2, Sp1 and cFos in the pancreatic cancer cell lines PaTu 8988t and PANC-1 and to analyse the relevance of this effect for the cells. MATERIALS AND METHODS: Stimulation with propofol and its effects on the expression of NFATc2, Sp1 and cFos were assessed by immunoblot. Cell cycle distribution was analysed by flow cytometry, and cell proliferation was measured with the ELISA BrdU assay. Propofol and siRNA against cFos were used for stimulation. RESULTS: Propofol regulated the expression of NFATc2, Sp1 and cFos. Stimulation with 250 µM or 500 µM propofol decreased NFATc2, Sp1 and cFos signalling in the Western blot analysis. At the same time, propofol significantly inhibited proliferation and activated cell cycle. The same proliferation behaviour was observed after transient cFos inhibition. These effects were potentiated by simultaneous stimulation with propofol and transient inhibition of cFos, further inhibiting cell proliferation. Interestingly, the cell cycle activation observed after stimulation with propofol alone was reversed in both cell lines. CONCLUSION: Anaesthetists only see oncological patients in a short time window. However, the perioperative period is increasingly recognised as a very vulnerable time with a major impact on tumour progression. Further studies are needed to identify the underlying mechanisms and to verify their clinical relevance, especially in anaesthesia.

Effect of NFATc2- and Sp1-mediated TNFalpha Regulation on the Proliferation and Migration Behavior of Pancreatic Cancer Cells.

BACKGROUND/AIM: One in two people will develop a tumor during their lifetime. Adenocarcinoma of the pancreas is one of the most aggressive types of cancer in humans with very poor long-term survival. A central role in the carcinogenesis of pancreatic cancer has been attributed to NFAT transcription factors. Previous studies have identified the transcription factor Sp1 as a binding partner of NFATc2 in pancreatic cancer. Using expression profile analysis, our group was able to identify the tumor necrosis factor TNFalpha as a target gene of the interaction between NFATc2 and Sp1. The present study investigated the effect of TNFalpha over-expression via the transcription factors NFATc2 and Sp1 on the pancreatic cancer cell lines PaTu 8988t and PANC-1. MATERIALS AND METHODS: Transient transfection of NFATc2, Sp1, and TNFalpha siRNAs and their effects on the expression were investigated with immunoblot. Cell proliferation was measured with the ELISA BrdU assay. Cell migration was assayed with a Cell Migration Assay Kit using a Boyden chamber. RESULTS: Inhibition of the transfection factors NFATc2, Sp1, or TNFalpha by siRNA significantly inhibited proliferation, which was exacerbated when using the combination of NFATc2 and Sp1. TNFalpha was able to counterbalance this effect. In contrast to proliferation, migration of pancreatic cancer cells was increased by inhibiting these transfection factors. CONCLUSION: Tumor progression is strongly influenced by transcriptional changes in signaling cascades and oncogene mutations as well as by changes in tumor suppressor genes. Further studies are needed to understand the underlying mechanisms of these processes.

SP1 transcriptionally upregulates the expression of APOC3 in KGN cells to promote disease progression by regulating TLR2/NF-κB signalling pathway.

INTRODUCTION: Apolipoprotein C3 (APOC3) is known for its important functions in metabolism-related diseases. However, the function and molecular mechanism of APOC3 in polycystic ovarian syndrome (PCOS) have not been reported. MATERIAL AND METHODS: Quantitative polymerase chain reaction and western blot assays were used to detect the expression of APOC3 in KGN cells. Small interference APOC3 (siAPOC3) was applied to reduce APOC3 expression, and the proliferation ability of human granulosa cell line (KGN cells) was measured by cell counting kit-8 and colony formation assays. The protein levels of key genes related to apoptosis were detected by western blot assay. The transcriptional regulator of APOC3 was predicted by the UCSC and PROMO website, and verified by dual luciferase assay. siAPOC3 and pcDNA3.1-specific protein 1 (SP1) vector were co-transfected into KGN cells to detect the function of SP1 and APOC3 in KGN cells. RESULTS: APOC3 was overexpressed in KGN cells, and siAPOC3 transfection significantly reduced the growth ability of KGN cells and increased the apoptosis ability of KGN cells. SP1 directly bound to the promoter of APOC3 and transcriptional regulated APOC3 expression. Overexpression of SP1 increased the growth ability of KGN cells and decreased the apoptosis ability of KGN cells, which were reversed after siAPOC3 transfection. The increased levels of toll-like receptor 2 (TLR2) and p65 phosphorylation (p-P65) nuclear factor kappa B (NF-κB) caused by SP1 overexpression were inhibited by siAPOC3 transfection. APOC3, transcriptionally regulated by SP1, promoted the growth of KGN cells, and inhibited the apoptosis by regulating TLR2/NF-κB signalling pathway.

LINC00955 suppresses colorectal cancer growth by acting as a molecular scaffold of TRIM25 and Sp1 to Inhibit DNMT3B-mediated methylation of the PHIP promoter.

BACKGROUND: Long non-coding RNAs play an important role in the development of colorectal cancer (CRC), while many CRC-related lncRNAs have not yet been identified. METHODS: The relationship between the expression of LINC00955 (Long Intergenic Non-protein Coding RNA 955) and the prognosis of colorectal cancer patients was analyzed using the sequencing results of the TCGA database. LINC00955 expression levels were measured using qRT-PCR. The anti-proliferative activity of LINC00955 was evaluated using CRC cell lines in vitro and xenograft models in nude mice in vivo. The interaction of TRIM25-Sp1-DNMT3B-PHIP-CDK2 was analyzed by western blotting, protein degradation experiment, luciferase, RNA-IP, RNA pull-down assays and immunohistochemically analysis. The biological roles of LINC00955, tripartite motif containing 25 (TRIM25), Sp1 transcription factor (Sp1), DNA methyltransferase 3 beta (DNMT3B), pleckstrin homology domain interacting protein (PHIP), cyclin dependent kinase 2 (CDK2) in colorectal cancer cells were analyzed using ATP assays, Soft agar experiments and EdU assays. RESULTS: The present study showed that LINC00955 is downregulated in CRC tissues, and such downregulation is associated with poor prognosis of CRC patients. We found that LINC00955 can inhibit CRC cell growth both in vitro and in vivo. Evaluation of its mechanism of action showed that LINC00955 acts as a scaffold molecule that directly promotes the binding of TRIM25 to Sp1, and promotes ubiquitination and degradation of Sp1, thereby attenuating transcription and expression of DNMT3B. DNMT3B inhibition results in hypomethylation of the PHIP promoter, in turn increasing PHIP transcription and promoting ubiquitination and degradation of CDK2, ultimately leading to G0/G1 growth arrest and inhibition of CRC cell growth. CONCLUSIONS: These findings indicate that downregulation of LINC00955 in CRC cells promotes tumor growth through the TRIM25/Sp1/DNMT3B/PHIP/CDK2 regulatory axis, suggesting that LINC00955 may be a potential target for the therapy of CRC.

Sp1 mediated the inhibitory effect of glutamate on pulmonary surfactant synthesis.

BACKGROUND: Studies have shown that the release of endogenous glutamate (Glu) participates in lung injury by activating N-methyl-D-aspartate receptor (NMDAR), but the mechanism is still unclear. This study was to investigate the effects and related mechanisms of Glu on the lipid synthesis of pulmonary surfactant (PS) in isolated rat lung tissues. METHODS: The cultured lung tissues of adult SD rats were treated with Glu. The amount of [3H]-choline incorporation into phosphatidylcholine (PC) was detected. RT-PCR and Western blot were used to detect the changes of mRNA and protein expression of cytidine triphosphate: phosphocholine cytidylyltransferase alpha (CCTα), a key regulatory enzyme in PC biosynthesis. Western blot was used to detect the expression of NMDAR1, which is a functional subunit of NMDAR. Specific protein 1 (Sp1) expression plasmids were used. After transfected with Sp1 expression plasmids, the mRNA and protein levels of CCTα were detected by RT-PCR and Western blot in A549 cells. After treated with NMDA and MK-801, the mRNA and protein levels of Sp1 were detected by RT-PCR and Western blot in A549 cells. RESULTS: Glu decreased the incorporation of [3H]-choline into PC in a concentration- and time- dependent manner. Glu treatment significantly reduced the mRNA and protein levels of CCTα in lungs. Glu treatment up-regulated NMDAR1 protein expression, and the NMDAR blocker MK-801 could partially reverse the reduction of [3H]-choline incorporation induced by Glu (10-4 mol/L) in lungs. After transfected with Sp1 plasmid for 30 h, the mRNA and protein expression levels of CCTα were increased and the protein expression of Sp1 was also up-regulated. After A549 cells were treated with NMDA, the level of Sp1 mRNA did not change significantly, but the expression of nucleus protein in Sp1 was significantly decreased, while the expression of cytoplasmic protein was significantly increased. However, MK-801could reverse these changes. CONCLUSIONS: Glu reduced the biosynthesis of the main lipid PC in PS and inhibited CCTα expression by activating NMDAR, which were mediated by the inhibition of the nuclear translocation of Sp1 and the promoter activity of CCTα. In conclusion, NMDAR-mediated Glu toxicity leading to impaired PS synthesis may be a potential pathogenesis of lung injury.

Sp1 Upregulation Bolsters the Radioresistance of Glioblastoma Cells by Promoting Double Strand Breaks Repair.

Radioresistance remains a critical obstacle in the clinical management of glioblastoma (GBM) by radiotherapy. Therefore, it is necessary to explore the molecular mechanisms underlying radioresistance to improve patient response to radiotherapy and increase the treatment efficacy. The present study aimed to elucidate the role of specificity protein 1 (Sp1) in the radioresistance of GBM cells. Different human GBM cell lines and tumor-bearing mice were exposed to ionizing radiation (IR). Cell survival was determined by the colony formation assay. The expression of genes and proteins in the cells and tissues was analyzed by RT-PCR and western blotting, respectively. The γ-H2AX, p-Sp1 and dependent protein kinase catalytic subunit (DNA-PKcs phospho S2056) foci were analyzed by immunofluorescence. Apoptotic rates were measured by flow cytometry. Sp1 was upregulated after IR in vitro and in vivo and knocking down Sp1-sensitized GBM cells to IR. Sp1 activated the DNA-PKcs promoter and increased its expression and activity. Furthermore, the loss of Sp1 delayed double-strand breaks (DSB) repair and increased IR-induced apoptosis of GBM cells. Taken together, IR upregulates Sp1 expression in GBM cells, enhancing the activity of DNA-PKcs and promoting IR-induced DSB repair, thereby leading to increased radioresistance.

Stroke by inducing HDAC9-dependent deacetylation of HIF-1 and Sp1, promotes TfR1 transcription and GPX4 reduction, thus determining ferroptotic neuronal death.

Background: The inhibition of histone deacetylase 9 (HDAC9) represents a promising druggable target for stroke intervention. Indeed, HDAC9 is overexpressed in neurons after brain ischemia where exerts a neurodetrimental role. However, mechanisms of HDAC9-dependent neuronal cell death are not yet well established. Methods: Brain ischemia was obtained in vitro by primary cortical neurons exposed to glucose deprivation plus reoxygenation (OGD/Rx) and in vivo by transient middle cerebral artery occlusion. Western blot and quantitative real-time polymerase chain reaction were used to evaluate transcript and protein levels. Chromatin immunoprecipitation was used to evaluate the binding of transcription factors to the promoter of target genes. Cell viability was measured by MTT and LDH assays. Ferroptosis was evaluated by iron overload and 4-hydroxynonenal (4-HNE) release. Results: Our results showed that HDAC9 binds to hypoxia-inducible factor 1 (HIF-1) and specificity protein 1 (Sp1), two transcription activators of transferrin 1 receptor (TfR1) and glutathione peroxidase 4 (GPX4) genes, respectively, in neuronal cells exposed to OGD/Rx. Consequently, HDAC9 induced: (1) an increase in protein level of HIF-1 by deacetylation and deubiquitination, thus promoting the transcription of the pro-ferroptotic TfR1 gene; and (2) a reduction in Sp1 protein levels by deacetylation and ubiquitination, thus resulting in a down-regulation of the anti-ferroptotic GPX4 gene. Supporting these results, the silencing of HDAC9 partially prevented either HIF-1 increase and Sp1 reduction after OGD/Rx. Interestingly, silencing of the neurodetrimental factors, HDAC9, HIF-1, or TfR1 or the overexpression of the prosurvival factors Sp1 or GPX4 significantly reduced a well-known marker of ferroptosis 4-HNE after OGD/Rx. More important, in vivo, intracerebroventricular injection of siHDAC9 reduced 4-HNE levels after stroke by preventing: (1) HIF-1 and TfR1 increase and thus the augmented intracellular iron overload; and (2) a reduction of Sp1 and its target gene GPX4. Conclusions: Collectively, results obtained suggest that HDAC9 mediates post-traslational modifications of HIF-1 and Sp1 that, in turn, increases TfR1 and decreases GPX4 expression, thus promoting neuronal ferroptosis in in vitro and in vivo models of stroke.

Sp1-mediated miR-193b suppresses atopic dermatitis by regulating HMGB1.

Atopic dermatitis (AD) is a chronic and recurrent inflammatory skin disease. Keratinocyte dysfunction plays a central role in AD development. MicroRNA is a novel player in many inflammatory and immune skin diseases. In this study, we investigated the potential function and regulatory mechanism of miR-193b in AD. Inflamed human keratinocytes (HaCaT) were established by tumor necrosis factor (TNF)-α/interferon (IFN)-γ stimulation. Cell viability was measured using MTT assay, while the cell cycle was analyzed using flow cytometry. The cytokine levels were examined by enzyme-linked immunosorbent assay. The interaction between Sp1, miR-193b, and HMGB1 was analyzed using dual luciferase reporter and/or chromatin immunoprecipitation (ChIP) assays. Our results revealed that miR-193b upregulation enhanced the proliferation of TNF-α/IFN-γ-treated keratinocytes and repressed inflammatory injury. miR-193b negatively regulated high mobility group box 1 (HMGB1) expression by directly targeting HMGB1. Furthermore, HMGB1 knockdown promoted keratinocyte proliferation and inhibited inflammatory injury by repressing nuclear factor kappa-B (NF-κB) activation. During AD progression, HMGB1 overexpression abrogated increase of keratinocyte proliferation and repression of inflammatory injury caused by miR-193b overexpression. Moreover, transcription factor Sp1 was identified as the biological partner of the miR-193b promoter in promoting miR-193b expression. Therefore, Sp1 upregulation promotes keratinocyte proliferation and represses inflammatory injury during AD development via promoting miR-193b expression and repressing HMGB1/NF-κB activation.

Astragalus polysaccharide ameliorates steroid-induced osteonecrosis of the femoral head by regulating miR-200b-3p-mediated Wnt/ß-catenin signaling pathway via inhibiting SP1 expression : Astragalus polysaccharide regulates SONFH via SP1.

BACKGROUND: Steroid-induced osteonecrosis of the femoral head (SONFH) is the necrosis of the femur bone caused by prolonged and massive use of corticosteroids. The present study probed into the significance of Astragalus polysaccharide (APS) in SONFH progression. METHODS: SONFH cell model was constructed using murine long bone osteocyte Y4 (MLO-Y4) cells and then treated with APS. mRNA microarray analysis selected differentially expressed genes between control group and SONFH group. RT-qPCR determined SP1 and miR-200b-3p expression. Levels of SP1, ß-catenin, autophagy-related proteins (LC3II/LC3I, Beclin1, p62) and apoptosis-related proteins (Bax, C-caspase3, C-caspase9, Bcl-2) were tested by Western blot. ChIP and luciferase reporter assays confirmed relationship between SP1 and miR-200b-3p. Fluorescence intensity of LC3 in cells was detected by immunofluorescence. Flow cytometry assessed cell apoptosis. Osteonecrosis tissues from SONFH mice were examined by HE and TRAP staining. RESULTS: APS induced autophagy and suppressed apoptosis in SONFH cell model. APS inhibited SP1 expression and SP1 overexpression reversed effects of APS on SONFH cell model. Mechanistically, SP1 targeted miR-200b-3p to inhibit Wnt/ß-catenin pathway. MiR-200b-3p depletion rescued the promoting effect of SP1 on SONFH cell model by activating Wnt/ß-catenin pathway. HE staining showed that APS treatment reduced the empty lacunae and alleviated inflammation in trabecular bone of SONFH mice. TRAP staining revealed decreased osteoclasts number in SONFH mice after APS treatment. CONCLUSION: APS regulated osteocyte autophagy and apoptosis via SP1/miR-200b-3p axis and activated Wnt/ß-catenin signaling, thereby alleviating SONFH, shedding new insights for therapy of SONFH.

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.

JWA inhibits nicotine-induced lung cancer stemness and progression through CHRNA5/AKT-mediated JWA/SP1/CD44 axis.

Cigarette smoking is an independent risk factor for lung cancer. Nicotine, as an addictive substance in tobacco and e-cigarettes, is known to promote tumor progression and metastasis despite being a non-carcinogen. As a tumor suppressor gene, JWA is widely involved in the inhibition of tumor growth and metastasis and the maintenance of cellular homeostasis, including in non-small cell lung cancer (NSCLC). However, the role of JWA in nicotine-induced tumor progression remains unclear. Here, we reported for the first time that JWA was significantly downregulated in smoking-related lung cancer and associated with overall survival. Nicotine exposure reduced JWA expression in a dose-dependent manner. Gene Set Enrichment Analysis (GSEA) analysis showed the tumor stemness pathway was enriched in smoking-related lung cancer, and JWA was negatively associated with stemness molecules CD44, SOX2, and CD133. JWA also inhibited nicotine-enhanced colony formation, spheroid formation, and EDU incorporation in lung cancer cells. Mechanically, nicotine downregulated JWA expression via the CHRNA5-mediated AKT pathway. Lower JWA expression enhanced CD44 expression through inhibition of ubiquitination-mediated degradation of Specificity Protein 1 (SP1). The in vivo data indicated that JAC4 through the JWA/SP1/CD44 axis inhibited nicotine-triggered lung cancer progression and stemness. In conclusion, JWA via down-regulating CD44 inhibited nicotine-triggered lung cancer cell stemness and progression. Our study may provide new insights to develop JAC4 for the therapy of nicotine-related cancers.

Copper induces liver lipotoxicity disease by up-regulating Nrf2 expression via the activation of MTF-1 and inhibition of SP1/Fyn pathway.

Excessive copper (Cu) intake leads to hepatic lipotoxicity disease, which has adverse effects on health, but the underlying mechanism is unclear. We found that Cu increased lipotoxicity by promoting Nrf2 recruitment to the ARE site in the promoters of five lipogenic genes (g6pd, 6pgd, me, icdh and pparγ). We also found that Cu affected the Nrf2 expression via different pathways: metal regulatory transcription factor 1 (MTF-1) mediated the Cu-induced Nrf2 transcriptional activation; Cu also enhanced the expression of Nrf2 by inhibiting the SP1 expression, which was achieved by inhibiting the negative regulator Fyn of Nrf2. These promoted the enrichment of Nrf2 in the nucleus and ultimately affected lipotoxicity. Thus, for the first time, we elucidated that Cu induced liver lipotoxicity disease by up-regulating Nrf2 expression via the MTF-1 activation and the inhibition of SP1/Fyn pathway. Our study elucidates the Cu-associated obesity and NAFLD for fish and possibly humans.

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.

X-ray inhibits FUT4-mediated proliferation in A549 cells by downregulating SP1 expression.

Objective: To identify the mechanism of down-regulation of Lewis Y antigen caused by X-ray irradiation. METHODS: The present original research study was conducted at Zhejiang University City College, Hangzhou, Republic of China, from 2020 to 2022. Western blotting, Co-immunoprecipitation (CO-IP), electrophoretic mobility shift assay and Cell Counting Kit-8 (CCK8) were performed to confirm the effect of X-ray irradiation on A549 cell proliferation and its mechanism. Data was analysed using Statistical Package for Social Sciences (SPSS) 11.5. RESULTS: The expressions of fucosyltransferase IV and Lewis Y were decreased after X-ray irradiation, thus inhibiting the proliferation of A549 lung cancer cells. Deoxyribonucleic acid damage caused by the irradiation caused higher level of poly- adenosinediphosphate-ribosylated Specific Protein 1(SP1), and translocation of SP1 from the nucleus, decreasing the expression of fucosyltransferase IV and Lewis Y. Conclusion: There was a significant role of glycosylation in radiation therapy for lung cancer.

Specificity Proteins (Sp) and Cancer.

The specificity protein (Sp) transcription factors (TFs) Sp1, Sp2, Sp3 and Sp4 exhibit structural and functional similarities in cancer cells and extensive studies of Sp1 show that it is a negative prognostic factor for patients with multiple tumor types. In this review, the role of Sp1, Sp3 and Sp4 in the development of cancer and their regulation of pro-oncogenic factors and pathways is reviewed. In addition, interactions with non-coding RNAs and the development of agents that target Sp transcription factors are also discussed. Studies on normal cell transformation into cancer cell lines show that this transformation process is accompanied by increased levels of Sp1 in most cell models, and in the transformation of muscle cells into rhabdomyosarcoma, both Sp1 and Sp3, but not Sp4, are increased. The pro-oncogenic functions of Sp1, Sp3 and Sp4 in cancer cell lines were studied in knockdown studies where silencing of each individual Sp TF decreased cancer growth, invasion and induced apoptosis. Silencing of an individual Sp TF was not compensated for by the other two and it was concluded that Sp1, Sp3 and Sp4 are examples of non-oncogene addicted genes. This conclusion was strengthened by the results of Sp TF interactions with non-coding microRNAs and long non-coding RNAs where Sp1 contributed to pro-oncogenic functions of Sp/non-coding RNAs. There are now many examples of anticancer agents and pharmaceuticals that induce downregulation/degradation of Sp1, Sp3 and Sp4, yet clinical applications of drugs specifically targeting Sp TFs are not being used. The application of agents targeting Sp TFs in combination therapies should be considered for their potential to enhance treatment efficacy and decrease toxic side effects.

Tra2ß Enhances Cell Proliferation by Inducing the Expression of Transcription Factor SP1 in Cervical Cancer.

Objective: In this study, the role and potential mechanism of transformer 2ß (Tra2ß) in cervical cancer were explored. Methods: The transcriptional data of Tra2ß in patients with cervical cancer from Gene Expression Profiling Interactive Analysis (GEPIA) and cBioPortal databases were investigated. The functions of Tra2ß were evaluated by using Western blot, MTT, colony formation, Transwell assays, and nude mouse tumor formation experiments. Target genes regulated by Tra2ß were studied by RNA-seq. Subsequently, representative genes were selected for RT-qPCR, confocal immunofluorescence, Western blot, and rescue experiments to verify their regulatory relationship. Results: The dysregulation of Tra2ß in cervical cancer samples was observed. Tra2ß overexpression in Siha and Hela cells enhanced cell viability and proliferation, whereas Tra2ß knockdown showed the opposite effect. Alteration of Tra2ß expression did not affect cell migration and invasion. Furthermore, tumor xenograft models verified that Tra2ß promoted cervical cancer growth. Mechanically, Tra2ß positively regulated the mRNA and protein level of SP1, which was critical for the proliferative capability of Tra2ß. Conclusion: This study demonstrated the important role of the Tra2ß/SP1 axis in the progression of cervical cancer in vitro and in vivo, which provides a comprehensive understanding of the pathogenesis of cervical cancer.