Overexpression Of Fibroblast Growth Factor Research Articles

Clinical advances and challenges in targeting FGF/FGFR signaling in lung cancer.

Fibroblast growth factors (FGFs) and their receptors regulate numerous cellular processes, such as metabolism and signal transduction, but can also drive tumorigenesis. Specifically, in lung cancer, the overexpression of FGFs, as well as the amplification, mutation and fusion of FGFR genes, are closely linked to the initiation, progression and resistance of the disease, suggesting that targeting FGF/FGFR is an attractive therapeutic strategy for lung cancer treatment. Nintedanib, a multitarget tyrosine kinase inhibitor (TKI) used in combination with docetaxel, has shown some success as a second-line therapy for lung cancer. However, clinical trials evaluating other FGFR inhibitors have yielded mixed results, indicating substantial complexity in targeting aberrant FGF/FGFR signaling. In this review, we describe the aberrations in FGF/FGFR signaling in lung cancer and summarize the clinical efficacy of FGFR inhibitors, such as multitarget TKIs, selective FGFR-TKIs and biological agents. We also discuss various challenges associated with FGFR targeting in lung cancer, including precision patient selection, toxicity and resistance. Finally, we provide perspectives on future directions, namely, developing novel FGFR-targeting drugs, such as FGFR degraders and more specific FGFR-TKIs, adopting combination therapy and targeting FGFs.

Overexpression of Fibroblast Growth Factor 8 Is a Predictor of Impaired Survival in Esophageal Squamous Cell Carcinoma and Correlates with ALK/EML4 Alteration.

FGF8, ALK, and EML4 have been identified as promising biomarkers in a number of malignancies. The aim of this study was to examine the prognostic role of FGF8, ALK, and EML4 in esophageal squamous cell carcinoma (ESCC). Methods: Consecutive patients with ESCC who underwent upfront resection were included in this study. ALK and EML4 gene status was evaluated by fluorescence in situ hybridization (FISH) using a triple-color break-apart single-fusion probe and a probe against 2p11. FGF8, ALK, and EML4 protein expression was determined by immunohistochemistry. Results: A total of 122 patients were included in this study. Multivariate analysis revealed that FGF8 overexpression is an independent negative prognostic factor for patients' overall survival (OS) (p = 0.04). Furthermore, a significant correlation between the expression of FGF8, and ALK (p = 0.04) and EML4 (p = 0.01) alteration was found. Conclusions: FGF8 overexpression is an adverse independent prognostic factor in patients with upfront resected ESCC. Furthermore, FGF8 expression significantly correlates with ALK and EML4 amplification and may therefore qualify as a future therapeutic target.

LTBP2 down-regulated FGF2 to repress vascular smooth muscle cell proliferation and vascular remodeling in a rat model of intracranial aneurysm

This work probed into the role of latent transforming growth factor beta binding protein 2 (LTBP2) in intracranial aneurysm (IA). The rats underwent IA modeling and then stereotactic injection of short hairpin RNA against LTBP2 (shLTBP2). Hematoxylin-eosin (HE) staining was employed to assess IA model and vascular remodeling. Rat vascular smooth muscle cells (VSMCs) were transfected with shLTBP2, LTBP2 overexpression plasmid and fibroblast growth factor 2 (FGF2) overexpression plasmid. The mRNA and protein expressions of LTBP2, FGF2 and mitochondrial apoptosis-related factors (Caspase-3, Cyt-c, Mcl-1) were tested through qRT-PCR and Western blot. Cell viability, proliferation and apoptosis were examined by cell counting kit-8, EdU assay and flow cytometry. The up-regulated LTBP2 and down-regulated FGF2 were detected in IA rats. LTBP2 knockdown promoted vascular remodeling and Mcl-1 level, and restrained cell apoptosis and expressions of Caspase-3 and Cyt-c in IA model rats. Moreover, LTBP2 knockdown potentiated cell viability, proliferation and FGF2 level, and repressed apoptosis in rat VSMCs, while overexpressed LTBP2 exerted opposite effects. FGF2 overexpression promoted proliferation and Mcl-1 level, and inhibited apoptosis and expressions of Caspase-3 and Cyt-c in rat VSMCs, which also reversed the effects of overexpressed LTBP2 on these aspects. Collectively, LTBP2 down-regulates FGF2 to repress VSMCs proliferation and vascular remodeling in an IA rat model.

Phosphorylation of LSD1 at serine 54 regulates genes involved in follicle selection by enhancing demethylation activity in chicken ovarian granulosa cells

Follicle selection in chicken refers to the process of selecting a follicle to enter hierarchy from a cohort of small yellow follicles (SY) with a diameter of 6 to 8 mm. The follicle being selected will develop rapidly and ovulate. Follicle selection is a key stage affecting chicken egg-laying performance. Our previous study showed that the phosphorylation level of lysine (K)-specific demethylase 1A (LSD1) at serine 54 (LSD1Ser54p) was significantly increased in F6 follicles compared to prehierarchal SY follicles, but its function was unclear. Here, the mechanism of this modification, the effect of LSD1Ser54p dephosphorylation on gene expression profile of chicken hierarchal granulosa cells and the function of fibroblast growth factor 9 (FGF9) that is regulated by LSD1Ser54p were further investigated. The modification of LSD1Ser54p was predicted to be mediated by cyclin-dependent kinase 5 (CDK5) and glycogen synthase kinase 3 (GSK3). Treatment of chicken hierarchal granulosa cells with CDK5 inhibitor significantly decreased LSD1Ser54p level (P < 0.05) and LSD1Ser54p interacted with CDK5, suggesting that, in the granulosa cells of chicken hierarchal follicles, LSD1Ser54p modification was carried out by CDK5. When the LSD1Ser54p level decreased in the granulosa cells of chicken hierarchal follicles, both the mRNA expression of FGF9 and α-actinin 2 (ACTN2) and the H3K4me2 level in their promoter regions significantly increased (P < 0.05), indicating that this phosphorylation modification enhanced the demethylation activity of LSD1. Moreover, in chicken hierarchal granulosa cells, overexpression of chicken FGF9 stimulated their proliferation and increased the mRNA expression of hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1 (Hsd3b) and steroidogenic acute regulatory protein (StAR). This study collectively revealed that phosphorylation of LSD1 at serine 54 by CDK5 enhanced its demethylation activity in chicken ovarian granulosa cells and regulated genes including FGF9 that is engaged in chicken follicle selection.

MiR-129-5p/FGF2 Axis is Associated with Homocysteine-induced Human Umbilical Vein Endothelial Cell Injury.

Homocysteine (Hcy)-induced endothelial cell injury is a key event in atherosclerosis pathogenesis. In this study, we aimed to explore the mechanisms underlying Hcy-induced endothelial injury by assessing the effects of Hcy on endothelial cell proliferation and the microRNA (miR)-129-5p/fibroblast growth factor 2 (FGF2) axis. Human umbilical vein endothelial cells (HUVECs) were treated with Hcy to construct an endothelial cell injury model. Expression levels of FGF2 in Hcy-induced HUVECs were determined using quantitative real-time polymerase chain reaction and western blotting. An FGF2 overexpression lentiviral vector was constructed to upregulate FGF2 expression in HUVECs via lentivirus transduction. A cell counting kit-8 assay was used to explore the effects of FGF2 overexpression on HUVEC proliferation. An upstream regulatory miRNA was predicted, and its targetbinding relationship with FGF2 was evaluated using a dual-luciferase reporter assay. We found that FGF2 expression in HUVECs was inhibited by Hcy treatment. Lentivirus transduction led to the overexpression of FGF2 in HUVECs, which significantly reversed the effect of Hcy on endothelial cell proliferation. miR-129-5p was experimentally validated as an upstream regulator of FGF2, and its decreased levels in HUVECs led to increased FGF2 expression. In addition, HUVEC proliferation was enhanced by the knockdown of miR-129-5p, and this effect was reversed by Hcy treatment. Taken together, the results of this study revealed that Hcy inhibits FGF2 expression in HUVECs, and FGF2 is regulated by upstream miR-129-5p to improve the effect of Hcy on endothelial cell proliferation.

Co-exposure to fluoride and sulfur dioxide induces abnormal enamel mineralization in rats via the FGF9-mediated MAPK signaling pathway

Fluoride (F) and sulfur dioxide (SO2) contamination is recognized as a public health concern worldwide. Our previous research has shown that Co-exposure to F and SO2 can cause abnormal enamel mineralization. Ameloblastin (AMBN) plays a crucial role in the process of enamel mineralization. However, the process by which simultaneous exposure to F and SO2 influences enamel formation by regulating AMBN expression still needs to be understood. This study aimed to establish in vivo and in vitro models of F–SO2 Co-exposure and investigate the relationship between AMBN and abnormal enamel mineralization. By overexpressing/knocking out the Fibroblast Growth Factor 9 (FGF9) gene, we investigated the impact of FGF9-mediated Mitogen-Activated Protein Kinase (MAPK) signaling on AMBN synthesis to elucidate the mechanism underlying the induction of abnormal enamel mineralization by F–SO2 Co-exposure in rats. The results showed that F–SO2 exposure damaged the structure of rat enamel and ameloblasts. When exposed to F or SO2, gradual increases in the protein expression of FGF9 and phosphorylated p38 mitogen-activated protein kinase (p-P38) were observed. Conversely, the protein levels of AMBN, phosphorylated extracellular signal-regulated kinase (p-ERK), and phosphorylated c-Jun N-terminal kinase (p-JNK) were decreased. AMBN expression was significantly correlated with FGF9, p-ERK, and p-JNK expression in ameloblasts. Interestingly, FGF9 overexpression reduced the levels of p-ERK and p-JNK, worsening the inhibitory effect of F–SO2 on AMBN. Conversely, FGF9 knockout increased the phosphorylation of ERK and JNK, partially reversing the F–SO2-induced downregulation of AMBN. Taken together, these findings strongly demonstrate that FGF9 plays a critical role in F–SO2-induced abnormal enamel mineralization by regulating AMBN synthesis through the JNK and ERK pathways.

Quercetin relieves coronary atherosclerosis via regulating fibroblast growth factor 2.

This study aims to investigate the role of quercetin in coronary atherosclerosis and explore its possible mechanisms. Hematoxylin-eosin (H&E), immunohistochemical (IHC), and aniline blue staining were used to analyze the pathological changes in the cross-section of the aorta. Traditional Chinese Medicine Systems Pharmacology Database (TCMSP), Swiss Target Prediction, and PubChem were utilized to predict and screen the bioactive ingredients of traditional Chinese medicine (Huanglian, Yuxingcao, and Jinyinhua) for coronary atherosclerosis. Inflammatory factors and vascular protection parameters were quantitatively detected using ELISA and western blot. The proliferation and migration of vascular smooth muscle cells (VSMC) were evaluated using the Cell Counting Kit-8 (CCK-8), 5-ethynyl-2-deoxyuridine (EdU), and wound healing assays. The targets of quercetin were predicted using DisGeNET, Matascape, SWISSMODEL, cellular thermal shift assay (CETSA), and fluorescence titrimetric methods. Based on our findings, quercetin was identified as the active component of Huanglian, Yuxingcao, and Jinyinhua that exerted a positive effect on coronary atherosclerosis. In vivo and in vitro data demonstrated that quercetin improved the pathological changes in model mice and inhibited the proliferation, migration, and inflammatory response of VSMC cells. Specifically, we found that fibroblast growth factor 2 (FGF2) is a direct target of quercetin, and overexpression of FGF2 attenuated the anti-atherosclerosis function of quercetin. Overall, our study confirms the functional role of the quercetin-FGF2 axis in the progression of coronary atherosclerosis, providing a potential target for its treatment.

Molecular features of gastrointestinal stromal tumors “wild-type” (&lt;i&gt;KIT/PDGFRA&lt;/i&gt; WT)

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. Their main features are the expression of CD117 (KIT) and mutations of KIT or PDGFRA in 85 % of patients. however, 10–15 % of adult GIST and 85 % of pediatric GIST do not have KIT/PDGFRA mutations (KIT/PDGFRA WT GIST or “wild-type” GIST). The prognosis and clinical course of these tumors and GIST with KIT/PDGFRA mutations differ. “Wild-type” GIST are quite heterogeneous group of tumors in terms of clinical phenotype, genetic etiology, and molecular pathways. Gastrointestinal stromal tumors are divided into SDH-deficient and SDH-competent based on the succinate dehydrogenase (SDH) complex. SDH-deficient GIST occur predominantly in children and young patients with Carney–Stratakis syndrome and Carney triad; there are also sporadic tumors. More than half of SDH-deficient GIST contain mutations in SDHA, SDHB, SDHD or SDHC, while the rest are caused by hypermethylation of the SDHC promoter. SDH-competent “wild-type” GIST include tumors with BRAF, RAS, or NF1 mutations that activate the RAS-RAF-MAPK pathway and KIT/PDGFRA/SDH/RAS-P WT GIST subtype or “quadruple wild type” GIST. The genomic profiles of these tumors and GIST with KIT/PDGFRA mutation or SDH deficiency differ significantly. One of the features of “quadruple wild type” GIST is activation of the FGFR (fibroblast growth factor receptors) signaling pathway due to chimeric FGFR, FGFR mutations, or overexpression of FGF (fibroblast growth factor). Another feature is chimeric genes containing fragments of NTRK, BRAF, FGFR and other genes that behave as oncogene drivers. In “quadruple wild-type” GIST the somatic mutations in TP53, MAX, MEN1, CTNND2, CHD4, ARIDIA and other genes were revealed as well as in the cell cycle genes RB1, CDK4, CDKN1B. There is no specific treatment for patients with “wild-type” GIST; the choice of drug is determined by the genetic disorder. There is a need to improve our understanding of the molecular mechanisms underlying the different GIST subtypes to develop more effective therapeutic approaches.

FGF2 drives osteosarcoma metastasis through activating FGFR1-4 receptor pathway-mediated ICAM-1 expression

Osteosarcoma is a malignant tumor with high metastatic potential, such that the overall 5-year survival rate of patients with metastatic osteosarcoma is only 20%. Therefore, it is necessary to unravel the mechanisms of osteosarcoma metastasis to identify predictors of metastasis by which to develop new therapies. Fibroblast growth factor 2 (FGF2) is a growth factor involved in embryonic development, cell migration, and proliferation. The overexpression of FGF2 and FGF receptors (FGFRs) has been shown to enhance cancer cell proliferation in lung, breast, gastric, and prostate cancers as well as melanoma. Nonetheless, the roles of FGF2 and FGFRs in human osteosarcoma cells remain unknown. In the present study, we found that FGF2 was overexpressed in human osteosarcoma sections and correlated with lung metastasis. Treatment of FGF2 induced migration activity, invasion activity, and intercellular adhesion molecule (ICAM)-1 expression in osteosarcoma cells. In particular, the downregulation or antagonism of FGFR1-4 suppressed FGF2-induced ICAM-1 expression and cancer cell migration. Furthermore, FGFR1, FGFR2, FGFR3, and FGFR4 were involved in FGF2-induced the phospholipase Cβ/protein kinase Cα/proto-oncogene c-Src signaling pathway and triggered c-Jun nuclear translocation. Subsequent c-Jun upregulation of activator protein-1 transcription activity on the ICAM-1 promoter led to an increased migration of osteosarcoma cells. Moreover, the knockdown of endogenous FGF2 suppressed ICAM-1 expression and migration of osteosarcoma cells. These findings suggest that FGF2/FGFR1-4 signaling promotes metastasis via its direct downstream target gene ICAM-1, revealing a novel potential therapeutic target for osteosarcoma.

Fibroblast growth factor 9 (FGF9)-mediated neurodegeneration: Implications for progressive multiple sclerosis?

Fibroblast growth factor (FGF) signalling is dysregulated in multiple sclerosis (MS) and other neurological and psychiatric conditions, but there is little or no consensus as to how individual FGF family members contribute to disease pathogenesis. Lesion development in MS is associated with increased expression of FGF1, FGF2 and FGF9, all of which modulate remyelination in a variety of experimental settings. However, FGF9 is also selectively upregulated in major depressive disorder (MDD), prompting us to speculate it may also have a direct effect on neuronal function and survival. Transcriptional profiling of myelinating cultures treated with FGF1, FGF2 or FGF9 was performed, and the effects of FGF9 on cortical neurons investigated using a combination of transcriptional, electrophysiological and immunofluorescence microscopic techniques. The in vivo effects of FGF9 were explored by stereotactic injection of adeno-associated viral (AAV) vectors encoding either FGF9 or EGFP into the rat motor cortex. Transcriptional profiling of myelinating cultures after FGF9 treatment revealed a distinct neuronal response with a pronounced downregulation of gene networks associated with axonal transport and synaptic function. In cortical neuronal cultures, FGF9 also rapidly downregulated expression of genes associated with synaptic function. This was associated with a complete block in the development of photo-inducible spiking activity, as demonstrated using multi-electrode recordings of channel rhodopsin-transfected rat cortical neurons in vitro and, ultimately, neuronal cell death. Overexpression of FGF9 in vivo resulted in rapid loss of neurons and subsequent development of chronic grey matter lesions with neuroaxonal reduction and ensuing myelin loss. These observations identify overexpression of FGF9 as a mechanism by which neuroaxonal pathology could develop independently of immune-mediated demyelination in MS. We suggest targeting neuronal FGF9-dependent pathways may provide a novel strategy to slow if not halt neuroaxonal atrophy and loss in MS, MDD and potentially other neurodegenerative diseases.

Targeting hepatic serine-arginine protein kinase 2 ameliorates alcohol-associated liver disease by alternative splicing control of lipogenesis.

Lipid accumulation induced by alcohol consumption is not only an early pathophysiological response but also a prerequisite for the progression of alcohol-associated liver disease (ALD). Alternative splicing regulates gene expression and protein diversity; dysregulation of this process is implicated in human liver diseases. However, how the alternative splicing regulation of lipid metabolism contributes to the pathogenesis of ALD remains undefined. Serine-arginine-rich protein kinase 2 (SRPK2), a key kinase controlling alternative splicing, is activated in hepatocytes in response to alcohol, in mice with chronic-plus-binge alcohol feeding, and in patients with ALD. Such induction activates sterol regulatory element-binding protein 1 and promotes lipogenesis in ALD. Overexpression of FGF21 in transgenic mice abolishes alcohol-mediated induction of SRPK2 and its associated steatosis, lipotoxicity, and inflammation; these alcohol-induced pathologies are exacerbated in FGF21 knockout mice. Mechanistically, SRPK2 is required for alcohol-mediated impairment of serine-arginine splicing factor 10, which generates exon 7 inclusion in lipin 1 and triggers concurrent induction of lipogenic regulators-lipin 1β and sterol regulatory element-binding protein 1. FGF21 suppresses alcohol-induced SRPK2 accumulation through mammalian target of rapamycin complex 1 inhibition-dependent degradation of SRPK2. Silencing SRPK2 rescues alcohol-induced splicing dysregulation and liver injury in FGF21 knockout mice. These studies reveal that (1) the regulation of alternative splicing by SRPK2 is implicated in lipogenesis in humans with ALD; (2) FGF21 is a key hepatokine that ameliorates ALD pathologies largely by inhibiting SRPK2; and (3) targeting SRPK2 signaling by FGF21 may offer potential therapeutic approaches to combat ALD.

Inhibition of miR-182-5p Targets FGF9 to Alleviate Osteoarthritis.

The pathogenesis of osteoarthritis (OA) is complex and there is no specific drug for treatment. The aim of this study was to identify the molecular targets of OA therapy, focusing on the expression and biological functions of miR-182-5p and its target genes in OA. miR-182-5p and fibroblast growth factor 9 (FGF9) were overexpressed or knocked down in IL-1β-induced chondrocytes. An OA knee model was performed by surgically destroying the medial meniscus. The gene expression of miR-182-5p and FGF9 was calculated. The protein FGF9 was tested by western blotting. Cell counting kit-8 (CCK8), plate cloning assay, and flow cytometry were conducted to evaluate cell proliferation and apoptosis. The expression of inflammatory factors, tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and interleukin (IL)-8, was evaluated using enzyme-linked immunosorbent assay (ELISA). Dual-luciferase reporter assays validated the targeting relationship between miR-182-5p and FGF9. Hematoxylin-eosin (HE) and safranin O-fast Green (S-O) staining were utilized to access cartilage damage. Ki67 expression in cartilage was detected using immunohistochemistry (IHC). TdT-mediated dUTP nick-end labeling (TUNEL) assays were used to calculate the apoptosis rate of cartilage. The expression of miR-182-5p was upregulated, and FGF9 was downregulated in the IL-1β-induced chondrocytes. OA chondrocytes proliferation ability in the miR-182-5p mimics group was decreased, and the apoptosis rate and inflammatory factor were increased. Transfection with miR-182-5p inhibitor increased the proliferative ability and decreased the apoptosis rate in the IL-1β-induced chondrocytes. Transfection with miR-182-5p inhibitor reversed IL-1β-induced inflammatory factor release in chondrocytes. Targeted binding sites existed between miR-182-5p and FGF9. After overexpression of FGF9, the miR-182-5p effect on OA chondrocytes was reversed. The hyaline cartilage thickness and proteoglycan content decreased in OA rats, and this was reversed by miR-182-5p inhibitor treatment. miR-182-5p expression levels were increased in OA chondrocytes and regulated chondrocyte proliferation, apoptosis, and inflammation by targeting FGF9. miR-182-5p is a potential gene for OA treatment.

Overexpression of fibroblast growth factor 13 ameliorates amyloid-β-induced neuronal damage.

Previous studies have shown that fibroblast growth factor 13 is downregulated in the brain of both Alzheimer's disease mouse models and patients, and that it plays a vital role in the learning and memory. However, the underlying mechanisms of fibroblast growth factor 13 in Alzheimer's disease remain unclear. In this study, we established rat models of Alzheimer's disease by stereotaxic injection of amyloid-β (Aβ1-42)-induced into bilateral hippocampus. We also injected lentivirus containing fibroblast growth factor 13 into bilateral hippocampus to overexpress fibroblast growth factor 13. The expression of fibroblast growth factor 13 was downregulated in the brain of the Alzheimer's disease model rats. After overexpression of fibroblast growth factor 13, learning and memory abilities of the Alzheimer's disease model rats were remarkably improved. Fibroblast growth factor 13 overexpression increased brain expression levels of oxidative stress-related markers glutathione, superoxide dismutase, phosphatidylinositol-3-kinase, AKT and glycogen synthase kinase 3β, and anti-apoptotic factor BCL. Furthermore, fibroblast growth factor 13 overexpression decreased the number of apoptotic cells, expression of pro-apoptotic factor BAX, cleaved-caspase 3 and amyloid-β expression, and levels of tau phosphorylation, malondialdehyde, reactive oxygen species and acetylcholinesterase in the brain of Alzheimer's disease model rats. The changes were reversed by the phosphatidylinositol-3-kinase inhibitor LY294002. These findings suggest that overexpression of fibroblast growth factor 13 improved neuronal damage in a rat model of Alzheimer's disease through activation of the phosphatidylinositol-3-kinase/AKT/glycogen synthase kinase 3β signaling pathway.

Circ_ARHGAP32 acts as miR-665 sponge to upregulate FGF2 to promote ox-LDL induced vascular smooth muscle cells proliferation and migration.

Circular RNA (circRNA) is considered to be an important regulator of human diseases, including atherosclerosis (AS). However, the role of circ_ARHGAP32 in AS formation needs further confirmation. To explore the role of circ_ARHGAP32 in AS formation. Oxidized low density lipoprotein (ox-LDL) was used to treat vascular smooth muscle cells (VSMCs) to mimic AS cell models in vitro. The expression of circ_ARHGAP32, microRNA (miR)-665, and fibroblast growth factor 2 (FGF2) was analyzed by quantitative real-time PCR. VSMCs function was measured by EdU assay, cell counting kit 8 assay and transwell assay. Protein expression was determined using western blot analysis. Dual-luciferase reporter assay and RNA pull-down assay were performed to verify RNA interaction. Circ_ARHGAP32 was highly expressed in AS patients and ox-LDL-induced VSMCs. Knockdown of circ_ARHGAP32 repressed ox-LDL-induced proliferation and migration in VSMCs. Circ_ARHGAP32 sponged miR-665 to positively regulate FGF2. MiR-665 inhibitor reversed the regulation of sh-circ_ARHGAP32 on ox-LDL-induced VSMCs proliferation and migration. MiR-665 also had a suppressive effect on the proliferation and migration of ox-LDL-induced VSMCs, and this effect could be reversed by FGF2 overexpression. Circ_ARHGAP32 might be a potential target for AS treatment, which promoted ox-LDL-induced VSMCs proliferation and migration by regulating miR-665/FGF2 network.

Silencing of long non-coding RNA TUC338 inhibits the malignant phenotype of nasopharyngeal cancer cells via modulating the miR-1226-3p/FGF2 axis

Long noncoding RNAs (lncRNAs) have been suggested as essential regulators in the cancer progression. LncRNA TUC338 was found to promote the malignancy of various cancers, however, the involvement of TUC338 in nasopharyngeal cancer (NPC) has not been well characterized. Here, our results found the significant overexpression of TUC338 in NPC tissues. Higher level of TUC338 was also observed in NPC cells. Interestingly, NPC patients harboring overexpressed TUC338 have worse prognosis. Functional study indicated that down-regulated TUC338 remarkably suppressed the NPC cell proliferation and cell migration. Notably, depletion of TUC338 significantly inhibited the in vivo tumor growth. Mechanistically, TUC338 acted as molecular sponge of miR-1226-3p and attenuated the negative regulation of miR-1226-3p on the expression of fibroblast growth factor 2 (FGF2). Down-regulation of TUC338 inhibited FGF2 expression in NPC cells and tumor tissues. Overexpression of FGF2 attenuated the suppressed NPC proliferation upon the depletion of TUC338. Our results demonstrated the novel function of TUC338/miR-1226-3p/FGF2 axis in NPC progression, suggesting the potential diagnosis and therapeutics significance of TUC338 in NPC.

Fibroblast Growth Factor-2 (FGF-2) Expression in Pterygia Using Cell Spot Arrays.

Fibroblast growth factor (FGF) is a main regulator of cell differentiation, cell migration and angiogenesis in normal and abnormal conjunctiva epithelia, but specific mechanisms of its aberrant expression are yet to be investigated. In the present study, we investigated FGF-2 protein expression within several pterygia. Using a liquid-based cytology assay, we obtained cell specimens from pterygia and healthy tissues directly from patients. A combination of immunocytochemistry followed by digital image analysis showed significant overexpression of FGF-2 in all the examined pterygia. In 30/60 (50%) cases there were high levels of staining intensity, whereas in the remaining 30/60 (50%) cases there were moderate levels of expression. FGF-2 levels of the control group were significantly lower in comparison with the pterygia group. There was no significant correlation between FGF-2 levels and either sex or location of the pterygium. FGF-2 levels had a significant correlation with morphological characteristics of the pterygia. More specifically, FGF-2 levels were significantly higher in the pterygia with a fleshy morphology. Interestingly, recurrent lesions demonstrated high expression levels. An overexpression of FGF-2 has been observed frequently in pterygia, where it may play a crucial role in determining the lesion’s progression. FGF-2 upregulation correlates with the morphology of pterygia and its tendency to recur. Cell spot analysis based on liquid-based cytology is a simple, yet effective, method for detecting a broad spectrum of protein markers and could be useful in analyzing potential pterygia patient samples.

Alternative polyadenylation writer CSTF2 forms a positive loop with FGF2 to promote tubular epithelial-mesenchymal transition and renal fibrosis

Effective therapies for renal fibrosis, the common endpoint for most kidney diseases, are lacking. We previously reported that alternative polyadenylation (APA) drives transition from acute kidney injury to chronic kidney disease, suggesting a potential role for APA in renal fibrogenesis. Here, we found that among canonical APA writers, CSTF2 expression was upregulated in tubular epithelial cells (TEC) of fibrotic kidneys. CSTF2 was also identified as a TGF-β-inducible pro-fibrotic gene. Further analysis revealed that CSTF2 promoted epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) overproduction in TEC by inducing 3’UTR shortening and upregulation of the expression of basic fibroblast growth factor 2 (FGF2). Additionally, 3’UTR shortening stabilised FGF2 mRNA through miRNA evasion. Interestingly, FGF2 enhanced CSTF2 expression, leading to the forming of a CSTF2-FGF2 positive loop in TEC. Furthermore, CSTF2 knockdown alleviated unilateral ureteral obstruction-induced renal fibrosis in vivo. Finally, we developed a CSTF2-targeted antisense oligonucleotide (ASO) and validated its effectiveness in vitro. These results indicate that the expression of the APA writer, CSTF2, is upregulated by TGF-β and CSTF2 facilitates TGF-β-induced FGF2 overexpression, forming a TGF-β-CSTF2-FGF2 pro-fibrotic axis in TEC. CSTF2 is a potentially promising target for renal fibrosis that does not directly disrupt TGF-β.

Identification of the regulatory role of the circ_0004788/miR-515-5p/FGF2 network in nasopharyngeal carcinoma development.

CircularRNAs (circRNAs) played vital roles in nasopharyngeal carcinoma (NPC). However, the impacts of circ_0004788 on the development of NPC have not been explored. Cell counting kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU) and colony formation assays were applied to determine cell proliferation. Wound healing, transwell invasion assay, tube formation assay, and flow cytometry were employed for the detection of cell migration, invasion, angiogenesis, and apoptosis, respectively. Xenograft tumor experiment was used to explore the biological role of circ_0004788 in NPC in vivo. Circ_0004788 and fibroblast growth factor 2 (FGF2) were significantly elevated, and microRNA-515-5p (miR-515-5p) was dramatically decreased in NPC tissues and cells. The impacts of circ_0004788 knockdown on cell progression in NPC cells were reversed by miR-515-5p inhibitor, and FGF2 overexpression could block the suppressive effect of miR-515-5p on cell progression in NPC cells. Circ_0004788 knockdown restrained the progression of NPC via the miR-515-5p/FGF2 axis.

CircSLC16A12 Absence Inhibits High Glucose-Induced Dysfunction in Retinal Microvascular Endothelial Cells through Mediating miR-140-3p/FGF2 Axis in Diabetic Retinopathy

PurposeDiabetic retinopathy (DR) is a common microvascular complication of diabetes mellitus which can cause irreversible visual impairment and blindness. We intended to investigate the function of circular RNA (circRNA) solute carrier family 16 member 12 (SLC16A12) in DR progression.MethodsReverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were applied to measure RNA and protein expression. Cell apoptosis was analyzed by flow cytometry (FCM) analysis. The angiogenesis ability was assessed by tube formation assay. Enzyme-linked immunosorbent assay (ELISA) was performed to analyze the release of inflammatory cytokines. Cell oxidative stress status was evaluated using commercial kits. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay, and RNA-pull down assay were conducted to confirm the intermolecular interactions.ResultsCircSLC16A12 level was enhanced in the serum samples of DR patients and high glucose (HG)-treated HRECs. CircSLC16A12 absence protected HRECs from HG-induced apoptosis, blood-retinal barrier (BRB) injury, tube formation, inflammatory response, and oxidative stress. CircSLC16A12 acted as a sponge for microRNA-140-3p (miR-140-3p), and circSLC16A12 knockdown-mediated effects were largely reversed by the absence of miR-140-3p in HRECs under HG condition. miR-140-3p interacted with the 3’ untranslated region (3’UTR) of fibroblast growth factor 2 (FGF2), and the overexpression of FGF2 largely overturned miR-140-3p overexpression-mediated effects in HRECs. CircSLC16A12 interference reduced the expression of FGF2 by up-regulating miR-140-3p in HRECs.ConclusionCircSLC16A12 silencing suppressed HG-induced dysfunction in HRECs partly by targeting miR-140-3p/FGF2 axis.

FGF-2–dependent signaling activated in aged human skeletal muscle promotes intramuscular adipogenesis

Aged skeletal muscle is markedly affected by fatty muscle infiltration, and strategies to reduce the occurrence of intramuscular adipocytes are urgently needed. Here, we show that fibroblast growth factor-2 (FGF-2) not only stimulates muscle growth but also promotes intramuscular adipogenesis. Using multiple screening assays upstream and downstream of microRNA (miR)-29a signaling, we located the secreted protein and adipogenic inhibitor SPARC to an FGF-2 signaling pathway that is conserved between skeletal muscle cells from mice and humans and that is activated in skeletal muscle of aged mice and humans. FGF-2 induces the miR-29a/SPARC axis through transcriptional activation of FRA-1, which binds and activates an evolutionary conserved AP-1 site element proximal in the miR-29a promoter. Genetic deletions in muscle cells and adeno-associated virus-mediated overexpression of FGF-2 or SPARC in mouse skeletal muscle revealed that this axis regulates differentiation of fibro/adipogenic progenitors in vitro and intramuscular adipose tissue (IMAT) formation in vivo. Skeletal muscle from human donors aged >75 y versus <55 y showed activation of FGF-2-dependent signaling and increased IMAT. Thus, our data highlights a disparate role of FGF-2 in adult skeletal muscle and reveals a pathway to combat fat accumulation in aged human skeletal muscle.