miR-493-5p Silenced by DNA Methylation Promotes Angiogenesis via Exosomes and VEGF-A-Mediated Intracellular Cross-Talk Between ESCC Cells and HUVECs.

Background: Exosomal microRNAs (miRNAs) in the tumor microenvironment play crucial roles in tumorigenesis and tumor progression by participating in intercellular cross-talk. However, the functions of exosomal miRNAs and the mechanisms by which they regulate esophageal squamous cell carcinoma (ESCC) progression are unclear. Methods: RNA sequencing and GEO analysis were conducted to identify candidate exosomal miRNAs involved in ESCC development. Receiver operating characteristic curve analysis was performed to assess the diagnostic value of plasma exosomal miR-493-5p. EdU, tube formation and Transwell assays were used to investigate the effects of exosomal miR-493-5p on human umbilical vein endothelial cells (HUVECs). A subcutaneous xenograft model was used to evaluate the antitumor effects of miR-493-5p and decitabine (a DNA methyltransferase inhibitor). The relationship between miR-493-5p and SP1/SP3 was revealed via a dual-luciferase reporter assay. A series of rescue assays were subsequently performed to investigate whether SP1/SP3 participate in exosomal miR-493-5p-mediated ESCC angiogenesis. Results: We found that miR-493-5p expression was notably reduced in the plasma exosomes of ESCC patients, which showed the high potential value in early ESCC diagnosis. Additionally, miR-493-5p, as a candidate tumor suppressor, inhibited the proliferation, migration and tube formation of HUVECs by suppressing the expression of VEGFA and exerted its angiostatic effect via exosomes. Moreover, we found that SP1/SP3 are direct targets of miR-493-5p and that re-expression of SP1/SP3 could reverse the inhibitory effects of miR-493-5p. Further investigation revealed that miR-493-5p expression could be regulated by DNA methyltransferase 3A (DNMT3A) and DNMT3B, and either miR-493-5p overexpression or restoration of miR-493-5p expression with decitabine increased the antitumor effects of bevacizumab. Conclusion: Exosomal miR-493-5p is a highly valuable ESCC diagnosis marker and inhibits ESCC-associated angiogenesis. miR-493-5p can be silenced via DNA methylation, and restoration of miR-493-5p expression with decitabine increases the antitumor effects of bevacizumab, suggesting its potential as a therapeutic target for ESCC treatment.

SP1 promotes high glucose-induced lens epithelial cell viability, migration and epithelial-mesenchymal transition via regulating FGF7 and PI3K/AKT pathway.

BACKGROUND: Diabetic cataract (DC) is a common complication of diabetes and its etiology and progression are multi-factorial. In this study, the roles of specific protein 1 (SP1) and fibroblast growth factor 7 (FGF7) in DC development were explored. METHODS: DC cell model was established by treating SRA01/04 cells with high glucose (HG). MTT assay was conducted to evaluate cell viability. Transwell assay and wound-healing assay were performed to assess cell migration and invasion. Western blot assay and qRT-PCR assay were conducted to measure the expression of N-cadherin, E-cadherin, Collagen I, Fibronectin, SP1 and FGF7 expression. CHIP assay and dual-luciferase reporter assay were conducted to analyze the combination between FGF7 and SP1. RESULTS: FGF7 was upregulated in DC patients and HG-induced SRA01/04 cells. HG treatment promoted SRA01/04 cell viability, migration, invasion and epithelial-mesenchymal transition (EMT), while FGF7 knockdown abated the effects. Transcription factor SP1 activated the transcription level of FGF7 and SP1 overexpression aggravated HG-induced SRA01/04 cell injury. SP1 silencing repressed HG-induced SRA01/04 cell viability, migration, invasion and EMT, but these effects were ameliorated by upregulating FGF7. Additionally, SP1 knockdown inhibited the PI3K/AKT pathway by regulating the transcription level of FGF7. CONCLUSION: Transcription factor SP1 activated the transcription level of FGF7 and the PI3K/AKT pathway to regulate HG-induced SRA01/04 cell viability, migration, invasion and EMT.

Role of Specificity Protein 1 (SP1) in Cardiovascular Diseases: Pathological Mechanisms and Therapeutic Potentials.

In mammals, specificity protein 1 (SP1) was the first Cys2-His2 zinc finger transcription factor to be isolated within the specificity protein and Krüppel-like factor (Sp/KLF) gene family. SP1 regulates gene expression by binding to Guanine-Cytosine (GC)-rich sequences on promoter regions of target genes, affecting various cellular processes. Additionally, the activity of SP1 is markedly influenced by posttranslational modifications, such as phosphorylation, acetylation, glycosylation, and proteolysis. SP1 is implicated in the regulation of apoptosis, cell hypertrophy, inflammation, oxidative stress, lipid metabolism, plaque stabilization, endothelial dysfunction, fibrosis, calcification, and other pathological processes. These processes impact the onset and progression of numerous cardiovascular disorders, including coronary heart disease, ischemia-reperfusion injury, cardiomyopathy, arrhythmia, and vascular disease. SP1 emerges as a potential target for the prevention and therapeutic intervention of cardiac ailments. In this review, we delve into the biological functions, pathophysiological mechanisms, and potential clinical implications of SP1 in cardiac pathology to offer valuable insights into the regulatory functions of SP1 in heart diseases and unveil novel avenues for the prevention and treatment of cardiovascular conditions.

SP1 regulates BMSC osteogenic differentiation through the miR-133a-3p/MAPK3 axis : SP1 regulates osteogenic differentiation of BMSCs.

BACKGROUND: The progression of osteoporosis (OP) can dramatically increase the risk of fractures, which seriously disturb the life of elderly individuals. Specific protein 1 (SP1) is involved in OP progression. However, the mechanism by which SP1 regulates OP progression remains unclear. OBJECTIVE: This study investigated the mechanism underlying the function of SP1 in OP. METHODS: SAMP6 mice were used to establish an in vivo model of age-dependent OP, and BALB/c mice were used as controls. BMSCs were extracted from two subtypes of mice. Hematoxylin and eosin staining were performed to mark the intramedullary trabecular bone structure to evaluate histological changes. ChIP assay was used to assess the targeted regulation between SP1 and miR-133a-3p. The binding sites between MAPK3 and miR-133a-3p were verified using a dual-luciferase reporter assay. The mRNA levels of miR-133a-3p and MAPK3 were detected using quantitative reverse transcription polymerase chain reaction (RT-qPCR). The protein expression of SP1, MAPK3, Colla1, OCN, and Runx2 was examined using Western blotting. Alkaline phosphatase (ALP) kit and Alizarin Red S staining were used to investigate ALP activity and mineralized nodules, respectively. RESULTS: The levels of SP1 and miR-133a-3p were upregulated, whereas the expression of MAPK3 was downregulated in BMSCs from SAMP6 mice, and miR-133a-3p inhibitor accelerated osteogenic differentiation in BMSCs. SP1 directly targeted miR-133a-3p, and MAPK3 was the downstream mRNA of miR-133a-3p. Mechanically, SP1 accelerated osteogenic differentiation in BMSCs via transcriptional mediation of the miR-133a-3p/MAPK3 axis. CONCLUSION: SP1 regulates osteogenic differentiation by mediating the miR-133a-3p/MAPK3 axis, which would shed new light on strategies for treating senile OP.

Discovery of a novel hybrid coumarin-hydroxamate conjugate targeting the HDAC1-Sp1-FOSL2 signaling axis for breast cancer therapy.

BACKGROUND: Breast cancer is one of the most lethal cancers in women. Despite significant advances in the diagnosis and treatment of breast cancer, many patients still succumb to this disease, and thus, novel effective treatments are urgently needed. Natural product coumarin has been broadly investigated since it reveals various biological properties in the medicinal field. Accumulating evidence indicates that histone deacetylase inhibitors (HDACIs) are promising novel anti-breast cancer agents. However, most current HDACIs exhibit only moderate effects against solid tumors and are associated with severe side effects. Thus, to develop more effective HDACIs for breast cancer therapy, hydroxamate of HDACIs was linked to coumarin core, and coumarin-hydroxamate hybrids were designed and synthesized. METHODS: A substituted coumarin moiety was incorporated into the classic hydroxamate HDACIs by the pharmacophore fusion strategy. ZN444B was identified by using the HDACI screening kit and cell viability assay. Molecular docking was performed to explore the binding mode of ZN444B with HDAC1. Western blot, immunofluorescent staining, cell viability, colony formation and cell migration and flow cytometry assays were used to analyze the anti-breast cancer effects of ZN444B in vitro. Orthotopic studies in mouse models were applied for preclinical evaluation of efficacy and toxicity in vivo. Proteomic analysis, dual-luciferase reporter assay, chromatin immunoprecipitation, co-immunoprecipitation, immunofluorescent staining assays along with immunohistochemical (IHC) analysis were used to elucidate the molecular basis of the actions of ZN444B. RESULTS: We synthesized and identified a novel coumarin-hydroxamate conjugate, ZN444B which possesses promising anti-breast cancer activity both in vitro and in vivo. A molecular docking model showed that ZN444B binds to HDAC1 with high affinity. Further mechanistic studies revealed that ZN444B specifically decreases FOS-like antigen 2 (FOSL2) mRNA levels by inhibiting the deacetylase activity of HDAC1 on Sp1 at K703 and abrogates the binding ability of Sp1 to the FOSL2 promoter. Furthermore, FOSL2 expression positively correlates with breast cancer progression and metastasis. Silencing FOSL2 expression decreases the sensitivity of breast cancer cells to ZN444B treatment. In addition, ZN444B shows no systemic toxicity in mice. CONCLUSIONS: Our findings highlight the potential of FOSL2 as a new biomarker and therapeutic target for breast cancer and that targeting the HDAC1-Sp1-FOSL2 signaling axis with ZN444B may be a promising therapeutic strategy for breast cancer.

RNA demethylase FTO participates in malignant progression of gastric cancer by regulating SP1-AURKB-ATM pathway.

Gastric cancer (GC) is the 5th most prevalent cancer and the 4th primary cancer-associated mortality globally. As the first identified m6A demethylase for removing RNA methylation modification, fat mass and obesity-associated protein (FTO) plays instrumental roles in cancer development. Therefore, we study the biological functions and oncogenic mechanisms of FTO in GC tumorigenesis and progression. In our study, FTO expression is obviously upregulated in GC tissues and cells. The upregulation of FTO is associated with advanced nerve invasion, tumor size, and LNM, as well as the poor prognosis in GC patients, and promoted GC cell viability, colony formation, migration and invasion. Mechanistically, FTO targeted specificity protein 1 and Aurora Kinase B, resulting in the phosphorylation of ataxia telangiectasia mutated and P38 and dephosphorylation of P53. In conclusion, the m6A demethylase FTO promotes GC tumorigenesis and progression by regulating the SP1-AURKB-ATM pathway, which may highlight the potential of FTO as a diagnostic biomarker for GC patients' therapy response and prognosis.

SP1 undergoes phase separation and activates RGS20 expression through super-enhancers to promote lung adenocarcinoma progression.

Lung adenocarcinoma (LUAD) is the leading cause of cancer-related death worldwide, but the underlying molecular mechanisms remain largely unclear. The transcription factor (TF) specificity protein 1 (SP1) plays a crucial role in the development of various cancers, including LUAD. Recent studies have indicated that master TFs may form phase-separated macromolecular condensates to promote super-enhancer (SE) assembly and oncogene expression. In this study, we demonstrated that SP1 undergoes phase separation and that its zinc finger 3 in the DNA-binding domain is essential for this process. Through Cleavage Under Targets & Release Using Nuclease (CUT&RUN) using antibodies against SP1 and H3K27ac, we found a significant correlation between SP1 enrichment and SE elements, identified the regulator of the G protein signaling 20 (RGS20) gene as the most likely target regulated by SP1 through SE mechanisms, and verified this finding using different approaches. The oncogenic activity of SP1 relies on its phase separation ability and RGS20 gene activation, which can be abolished by glycogen synthase kinase J4 (GSK-J4), a demethylase inhibitor. Together, our findings provide evidence that SP1 regulates its target oncogene expression through phase separation and SE mechanisms, thereby promoting LUAD cell progression. This study also revealed an innovative target for LUAD therapies through intervening in SP1-mediated SE formation.

HMGA1 promotes the progression of esophageal squamous cell carcinoma by elevating TKT-mediated upregulation of pentose phosphate pathway.

Esophageal squamous cell carcinoma (ESCC) possesses a poor prognosis and treatment outcome. Dysregulated metabolism contributes to unrestricted growth of multiple cancers. However, abnormal metabolism, such as highly activated pentose phosphate pathway (PPP) in the progression of ESCC remains largely unknown. Herein, we report that high-mobility group AT-hook 1 (HMGA1), a structural transcriptional factor involved in chromatin remodeling, promoted the development of ESCC by upregulating the PPP. We found that HMGA1 was highly expressed in ESCC. Elevated HMGA1 promoted the malignant phenotype of ESCC cells. Conditional knockout of HMGA1 markedly reduced 4-nitroquinoline-1-oxide (4NQO)-induced esophageal tumorigenesis in mice. Through the metabolomic analysis and the validation assay, we found that HMGA1 upregulated the non-oxidative PPP. With the transcriptome sequencing, we identified that HMGA1 upregulated the expression of transketolase (TKT), which catalyzes the reversible reaction in non-oxidative PPP to exchange metabolites with glycolytic pathway. HMGA1 knockdown suppressed the PPP by downregulating TKT, resulting in the reduction of nucleotides in ESCC cells. Overexpression of HMGA1 upregulated PPP and promoted the survival of ESCC cells by activating TKT. We further characterized that HMGA1 promoted the transcription of TKT by interacting with and enhancing the binding of transcription factor SP1 to the promoter of TKT. Therapeutics targeting TKT with an inhibitor, oxythiamine, reduced HMGA1-induced ESCC cell proliferation and tumor growth. Together, in this study, we identified a new role of HMGA1 in ESCCs by upregulating TKT-mediated activation of PPP. Our results provided a new insight into the role of HMGA1/TKT/PPP in ESCC tumorigenesis and targeted therapy.

Microglial Sp1 induced LRRK2 upregulation in response to manganese exposure, and 17ß-estradiol afforded protection against this manganese toxicity.

Chronic exposure to elevated levels of manganese (Mn) causes a neurological disorder referred to as manganism, presenting symptoms similar to those of Parkinson's disease (PD), yet the mechanisms by which Mn induces its neurotoxicity are not completely understood. 17ß-estradiol (E2) affords neuroprotection against Mn toxicity in various neural cell types including microglia. Our previous studies have shown that leucine-rich repeat kinase 2 (LRRK2) mediates Mn-induced inflammatory toxicity in microglia. The LRRK2 promoter sequences contain three putative binding sites of the transcription factor (TF), specificity protein 1 (Sp1), which increases LRRK2 promoter activity. In the present study, we tested if the Sp1-LRRK2 pathway plays a role in both Mn toxicity and the protection afforded by E2 against Mn toxicity in BV2 microglial cells. The results showed that Mn induced cytotoxicity, oxidative stress, and tumor necrosis factor-α production, which were attenuated by an LRRK2 inhibitor, GSK2578215A. The overexpression of Sp1 increased LRRK2 promoter activity, mRNA and protein levels, while inhibition of Sp1 with its pharmacological inhibitor, mithramycin A, attenuated the Mn-induced increases in LRRK2 expression. Furthermore, E2 attenuated the Mn-induced Sp1 expression by decreasing the expression of Sp1 via the promotion of the ubiquitin-dependent degradation pathway, which was accompanied by increased protein levels of RING finger protein 4, the E3-ligase of Sp1, Sp1 ubiquitination, and SUMOylation. Taken together, our novel findings suggest that Sp1 serves as a critical TF in Mn-induced LRRK2 expression as well as in the protection afforded by E2 against Mn toxicity through reduction of LRRK2 expression in microglia.

Deciphering the TCF19/miR-199a-5p/SP1/LOXL2 pathway: Implications for breast cancer metastasis and epithelial-mesenchymal transition.

Globally, breast cancer (BC) is the predominant malignancy with a significant death rate due to metastasis. The epithelial-mesenchymal transition (EMT) is a fundamental initiator for metastatic progression. Through advanced computational strategies, TCF19 was identified as a critical EMT-associated gene with diagnostic and prognostic significance in BC, based on a novel EMT score. Molecular details and the pro-EMT impact of the TCF19/miR-199a-5p/SP1/LOXL2 axis were explored in BC cell lines through in vitro validations, and the oncogenic and metastatic potential of TCF19 and LOXL2 were investigated using subcutaneous and tail-vein models. Additionally, BC-specific enrichment of TCF19 and LOXL2 was measured using a distribution landscape driven by diverse genomic analysis techniques. Molecular pathways revealed that TCF19-induced LOXL2 amplification facilitated migratory, invasive, and EMT activities of BC cells in vitro, and promoted the growth and metastatic establishment of xenografts in vivo. TCF19 decreases the expression of miR-199a-5p and alters the nuclear dynamics of SP1, modulating SP1's affinity for the LOXL2 promoter, leading to increased LOXL2 expression and more malignant characteristics in BC cells. These findings unveil a novel EMT-inducing pathway, the TCF19/miR-199a-5P/SP1/LOXL2 axis, highlighting the pivotal role of TCF19 and suggesting potential for novel therapeutic approaches for more focused BC interventions.

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.

Exposure to coal dust exacerbates cognitive impairment by activating the IL6/ERK1/2/SP1 signaling pathway.

Coal dust (CD) is a common pollutant, and epidemiological surveys indicate that long-term exposure to coal dust not only leads to the occurrence of pulmonary diseases but also has certain impacts on cognitive abilities. However, there is little open-published literature on the effects and specific mechanisms of coal dust exposure on the cognition of patients with Mild Cognitive Impairment (MCI) and Alzheimer's Disease (AD). An animal model has been built in this study with clinical population samples to explore the changes in neuroinflammation and cognitive abilities with coal dust exposure. In the animal model, compared to C57BL/6 mice, APP/PS1 mice exposed to coal dust exhibited more severe cognitive impairment, accompanied by significantly elevated levels of neuroinflammatory factors Apolipoprotein E4 (AOPE4) and Interleukin-6 (IL6) in the hippocampus, and more severe neuronal damage. In clinical sample sequencing, it was found that there is significant upregulation of AOPE4, neutrophils, and IL6 expression in the peripheral blood of MCI patients compared to normal individuals. Mechanistically, cell experiments revealed that IL6 could promote the phosphorylation of ERK1/2 and enhance the expression of transcription factor SP1, thereby promoting AOPE4 expression. The results of this study suggest that coal dust can promote the upregulation of IL6 and AOPE4 in patients, exacerbating cognitive impairment.

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.

LKB1 inhibits telomerase activity resulting in cellular senescence through histone lactylation in lung adenocarcinoma.

Despite the confirmed role of LKB1 in suppressing lung cancer progression, its precise effect on cellular senescence is unknown. The aim of this research was to clarify the role and mechanism of LKB1 in restraining telomerase activity in lung adenocarcinoma. The results showed that LKB1 induced cellular senescence and apoptosis either in vitro or in vivo. Overexpression of LKB1 in LKB1-deficient A549 cells led to the inhibition of telomerase activity and the induction of telomere dysfunction by regulating telomerase reverse transcriptase (TERT) expression in terms of transcription. As a transcription factor, Sp1 mediated TERT inhibition after LKB1 overexpression. LKB1 induced lactate production and inhibited histone H4 (Lys8) and H4 (Lys16) lactylation, which further altered Sp1-related transcriptional activity. The telomerase inhibitor BIBR1532 was beneficial for achieving the optimum curative effect of traditional chemotherapeutic drugs accompanied by the glycolysis inhibitor 2DG. These data reveal a new mechanism by which LKB1 regulates telomerase activity through lactylation-dependent transcriptional inhibition, and therefore, provide new insights into the effects of LKB1-mediated senescence in lung adenocarcinoma. Our research has opened up new possibilities for the creation of new cancer treatments.

GBP1 promotes cutaneous squamous cell carcinoma proliferation and invasion through activation of STAT3 by SP1.

Cutaneous squamous cell carcinoma (cSCC) ranks as the second most prevalent skin tumour (excluding melanoma). However, the molecular mechanisms driving cSCC progression remain elusive. This study aimed to investigate GBP1 expression in cSCC and elucidate its potential molecular mechanisms underlying cSCC development. GBP1 expression was assessed across public databases, cell lines and tissue samples. Various assays, including clone formation, CCK8 and EdU were employed to evaluate cell proliferation, while wound healing and transwell assays determined cell migration and invasion. Subcutaneous tumour assays were conducted to assess in vivo tumour proliferation, and molecular mechanisms were explored through western blotting, immunofluorescence and immunoprecipitation. Results identified GBP1 as an oncogene in cSCC, with elevated expression in both tumour tissues and cells, strongly correlating with tumour stage and grade. In vitro and in vivo investigations revealed that increased GBP1 expression significantly enhanced cSCC cell proliferation, migration and invasion. Mechanistically, GBP1 interaction with SP1 promoted STAT3 activation, contributing to malignant behaviours. In conclusion, the study highlights the crucial role of the GBP1/SP1/STAT3 signalling axis in regulating tumour progression in cSCC. These findings provide valuable insights into the molecular mechanisms of cSCC development and offer potential therapeutic targets for interventions against cSCC.

P4HA2 promotes tumor progression and is transcriptionally regulated by SP1 in colorectal cancer.

P4HA2 has been implicated in various malignant tumors; however, its expression and functional role in colorectal cancer (CRC) remain poorly elucidated. This study aims to investigate the involvement of P4HA2 in CRC metastasis and progression, uncovering the underlying mechanisms. In colorectal cancer (CRC), P4HA2 exhibited overexpression, and elevated levels of P4HA2 expression were associated with an unfavorable prognosis. Functional assays demonstrated P4HA2's regulation of cell proliferation, and epithelial-mesenchymal transition (EMT) both in vitro and in vivo. Additionally, the AGO1 expression was correlated with P4HA2, and depletion of AGO1 reversed the proliferation and EMT function induced by P4HA2. Chromatin immunoprecipitation (ChIP) and luciferase assays suggested that the transcription factor SP1 binds to the promoter sequence of P4HA2, activating its expression in CRC. This study unveiled SP1 as a transcriptional regulator of P4HA2 in CRC and AGO1 is a probable target of P4HA2. In conclusion, P4HA2 emerges as a potential prognostic biomarker and promising therapeutic target in colorectal cancer.

Regulation of the RhoA exchange factor GEF-H1 by profibrotic stimuli through a positive feedback loop involving RhoA, MRTF, and Sp1.

RhoA and its effectors, the transcriptional coactivators myocardin-related transcription factor (MRTF) and serum response factor (SRF), control epithelial phenotype and are indispensable for profibrotic epithelial reprogramming during fibrogenesis. Context-dependent control of RhoA and fibrosis-associated changes in its regulators, however, remain incompletely characterized. We previously identified the guanine nucleotide exchange factor GEF-H1 as a central mediator of RhoA activation in renal tubular cells exposed to inflammatory or fibrotic stimuli. Here we found that GEF-H1 expression and phosphorylation were strongly elevated in two animal models of fibrosis. In the Unilateral Ureteral Obstruction mouse kidney fibrosis model, GEF-H1 was upregulated predominantly in the tubular compartment. GEF-H1 was also elevated and phosphorylated in a rat pulmonary artery banding (PAB) model of right ventricular fibrosis. Prolonged stimulation of LLC-PK1 tubular cells with tumor necrosis factor (TNF)-α or transforming growth factor (TGF)-ß1 increased GEF-H1 expression and activated a luciferase-coupled GEF-H1 promoter. Knockdown and overexpression studies revealed that these effects were mediated by RhoA, cytoskeleton remodeling, and MRTF, indicative of a positive feedback cycle. Indeed, silencing endogenous GEF-H1 attenuated activation of the GEF-H1 promoter. Of importance, inhibition of MRTF using CCG-1423 prevented GEF-H1 upregulation in both animal models. MRTF-dependent increase in GEF-H1 was prevented by inhibition of the transcription factor Sp1, and mutating putative Sp1 binding sites in the GEF-H1 promoter eliminated its MRTF-dependent activation. As the GEF-H1/RhoA axis is key for fibrogenesis, this novel MRTF/Sp1-dependent regulation of GEF-H1 abundance represents a potential target for reducing renal and cardiac fibrosis.NEW & NOTEWORTHY We show that expression of the RhoA regulator GEF-H1 is upregulated in tubular cells exposed to fibrogenic cytokines and in animal models of kidney and heart fibrosis. We identify a pathway wherein GEF-H1/RhoA-dependent MRTF activation through its noncanonical partner Sp1 upregulates GEF-H1. Our data reveal the existence of a positive feedback cycle that enhances Rho signaling through control of both GEF-H1 activation and expression. This feedback loop may play an important role in organ fibrosis.

LINC08148 promotes the caveola-mediated endocytosis of Zika virus through upregulating transcription of Src.

Long non-coding RNAs (lncRNAs) represent a new group of host factors involved in viral infection. Current study identified an intergenic lncRNA, LINC08148, as a proviral factor of Zika virus (ZIKV) and Dengue virus 2 (DENV2). Knockout (KO) or silencing of LINC08148 decreases the replication of ZIKV and DENV2. LINC08148 mainly acts at the endocytosis step of ZIKV but at a later stage of DENV2. RNA-seq analysis reveals that LINC08148 knockout downregulates the transcription levels of five endocytosis-related genes including AP2B1, CHMP4C, DNM1, FCHO1, and Src. Among them, loss of Src significantly decreases the uptake of ZIKV. Trans-complementation of Src in the LINC08148KO cells largely restores the caveola-mediated endocytosis of ZIKV, indicating that the proviral effect of LINC08148 is exerted through Src. Finally, LINC08148 upregulates the Src transcription through associating with its transcription factor SP1. This work establishes an essential role of LINC08148 in the ZIKV entry, underscoring a significance of lncRNAs in the viral infection. IMPORTANCE: Long non-coding RNAs (lncRNAs), like proteins, participate in viral infection. However, functions of most lncRNAs remain unknown. In this study, we performed a functional screen based on microarray data and identified a new proviral lncRNA, LINC08148. Then, we uncovered that LINC08148 is involved in the caveola-mediated endocytosis of ZIKV, rather than the classical clathrin-mediated endocytosis. Mechanistically, LINC08148 upregulates the transcription of Src, an initiator of caveola-mediated endocytosis, through binding to its transcription factor SP1. This study identifies a new lncRNA involved in the ZIKV infection, suggesting lncRNAs and cellular proteins are closely linked and cooperate to regulate viral infection.

The Loss of an Orphan Nuclear Receptor NR2E3 Augments Wnt/ß-catenin Signaling via Epigenetic Dysregulation that Enhances Sp1-ß catenin-p300 Interactions in Hepatocellular Carcinoma.

The orphan nuclear receptor NR2E3 (Nuclear receptor subfamily 2 group E, Member 3) is an epigenetic player that modulates chromatin accessibility to activate p53 during liver injury. Nonetheless, a precise tumor suppressive and epigenetic role of NR2E3 in hepatocellular carcinoma (HCC) development remains unclear. HCC patients expressing low NR2E3 exhibit unfavorable clinical outcomes, aligning with heightened activation of the Wnt/ß-catenin signaling pathway. The murine HCC models utilizing NR2E3 knockout mice consistently exhibits accelerated liver tumor formation accompanied by enhanced activation of Wnt/ß-catenin signaling pathway and inactivation of p53 signaling. At cellular level, the loss of NR2E3 increases the acquisition of aggressive cancer cell phenotype and tumorigenicity and upregulates key genes in the WNT/ß-catenin pathway with increased chromatin accessibility. This event is mediated through increased formation of active transcription complex involving Sp1, ß-catenin, and p300, a histone acetyltransferase, on the promoters of target genes. These findings demonstrate that the loss of NR2E3 activates Wnt/ß-catenin signaling at cellular and organism levels and this dysregulation is associated with aggressive HCC development and poor clinical outcomes. In summary, NR2E3 is a novel tumor suppressor with a significant prognostic value, maintaining epigenetic homeostasis to suppress the Wnt/ß-catenin signaling pathway that promotes HCC development.