Analysis and Investigation of Bioinformatics and Epigenetics Reveal the Underlying Mechanisms by which FLOT2 Modulates the Progression of Diffuse Large B-cell Lymphoma.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) poses a significant threat to the quality of life for people worldwide. Regrettably, effective treatment strategies for this disease remain elusive in clinical practice due to the unclear understanding of its molecular mechanisms. Therefore, this study was devised to address these issues and identify novel diagnostic, therapeutic, and prognostic biomarkers for DLBCL. METHODS: Gene expression and clinical data for DLBCL patients were retrieved from The Cancer Genome Atlas (TCGA) database, and relevant clinical data, tumor mutational burden (TMB), and gene expression levels were extracted. Bioinformatics analysis was conducted to screen for differentially expressed genes (DEGs). The prognostic significance of flotillin-2 (FLOT2) was assessed using Kaplan-Meier survival analysis. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analyses were employed to evaluate mRNA and protein levels of the genes. Cell proliferation, apoptosis, and invasion were assessed using cell counting kit-8 (CCK-8) assay, flow cytometry analysis, and Transwell assay, respectively. RESULTS: Our bioinformatics analysis revealed that FLOT2 was significantly overexpressed in DLBCL tissues compared to normal tissues, a finding corroborated by subsequent immunohistochemistry staining, qRT-PCR, and Western blot analyses. To elucidate its biological functions, shRNAs targeting FLOT2 were transfected into DLBCL cell lines (LY-3 and U2932), resulting in suppressed cell proliferation and invasion, while promoting apoptosis. Furthermore, a positive correlation between TMB and FLOT2 expression in DLBCL was observed. Subsequently, quanTIseq was utilized to calculate the immune score and assess FLOT2 gene expression. In DLBCL, FLOT2 gene expression was found to be associated with T cell CD4+ (non-regulatory) (p < 0.01), monocytes (p < 0.05), and uncharacterized cells (p < 0.05). Regarding immune checkpoint markers, including the cluster of differentiation 274 (CD274), cytotoxic T lymphocyte-associated antigen-4 (CTLA4), hepatitis A virus cellular receptor 2 (HAVCR2), lymphocyte activation gene-3 (LAG3), programmed cell death protein 1 (PDCD1), programmed cell death 1 ligand 2 (PDCD1LG2), Siglec-15 (SIGLEC15), and T cell immunoreceptor with Ig and ITIM domains (TIGIT), our analysis indicated that in DLBCL, FLOT2 exhibited a relationship only with TIGIT (p < 0.05). CONCLUSIONS: In summary, FLOT2 functions as an oncogene and is linked to DLBCL prognosis and the tumor microenvironment. Targeting FLOT2 deletion emerges as a novel strategy to impede DLBCL aggressiveness by inhibiting cell proliferation and invasion, ultimately inducing apoptotic cell death.

Flot2 deficiency facilitates B cell-mediated inflammatory responses and endotoxic shock.

Sepsis is a life-threatening disease characterized by multiple organ dysfunction. B cells play a pivotal role in sepsis. Here, we first observed the significantly reduced Flot2 gene expression in B cells from patients with bacterial sepsis and endotoxin-induced septic mice. However, the effects of Flot2 on sepsis and B-cell immunity remain unknown. Thus, we sorted B cells from Flot2 knockout (Flot2-/- ) mice, RNA-seq revealed significantly upregulated effector B cell (Beff) cytokines such as Il6, Il1b and Cxcl10 after Flot2 deficiency, while it showed no effect on the expression of regulatory B cell (Breg) cytokines such as Il10, Tgfb. Consistently, elevated Beff cytokine IL-6 and unchanged Breg cytokine IL-10 were shown in B cells from Flot2-/- mice. Similar results were subsequently observed in B cell-specific Flot2 knockout chimeric mice. Notably, Flot2 deficiency aggravated sepsis with increased lung injury and shortened survival time in vivo by facilitating Beffs but not Bregs. Taken together, our data identify Flot2 as a novel controller of B cells, Flot2 deficiency amplifies inflammation by affecting Beffs to participate in the pathogenesis and progression of sepsis.

Knockdown of PAF1 reduces cervical cancer cell proliferation, migration and invasion via retarding FLOT2-mediated MEK/ERK1/2 pathway.

Cervical cancer (CC) is a very usual reproductive malignant tumor in women. RNA polymerase II-associated factor 1 (PAF1) and flotillin-2 (FLOT2) both have been discovered to key participators in cancers' progression. However, the effects of PAF1/FLOT2 axis on CC development have not been probed. In this study, PAF1 and FLOT2 exhibited higher expression, and silencing of PAF1 down-regulated FLOT2 expression in CC. In addition, the regulatory effects of PAF1 suppression on CC progression were reversed after FLOT2 overexpression. Next, inhibition of PAF1 slowed the tumor growth in vivo through modulating FLOT2. Besides, down-regulation of PAF1 reduced FLOT2 expression to retard the MEK/ERK1/2 pathway. In conclusion, knockdown of PAF1 suppressed CC progression via retarding FLOT2-mediated MEK/ERK1/2 pathway. Our findings illustrated that the PAF1/FLOT2 axis may be useful bio-targets for CC treatment.

Loss of Flot2 expression in deep cerebellar nuclei neurons of mice with Niemann-Pick disease type C.

Niemann-Pick disease type C (NPC) is caused by a deficiency of the NPC1 or NPC2 gene, leading to storages of unesterified cholesterol and sphingolipids. Cerebellar ataxia is a main symptom of NPC and the deep cerebellar nuclei (DCN) is the sole signal output of the cerebellum. In this study, we explored the pathological changes in DCN neurons of Npc1 knockout mice (Npc1-). We first demonstrated that DCN neurons of Npc1- mice had prominent ganglioside GM2 accumulation in the late endosomes but not in the lysosomes. More importantly, Flot2 expression, a marker for the lipid rafts, was lost. Single-nucleus RNA sequencing analysis revealed a generalized reduction in gene expression in DCN neurons, though Camk1d, encoding one of the Ca2+/calmodulin-dependent protein kinases (CaMKs), increased in expression. We treated Npc1- mice with CaMK inhibitor KN-93, but CaMK1D expression increased further. We also fed Npc1- mice with two medications for NPC. We found that miglustat, a sphingolipid synthesis inhibitor, increased the expression of Flot2. Moreover, N-acetyl l-leucine (NALL), an experimental medicine for NPC, recovered Flot2 expression. Therefore, our data suggest that in Npc1- mice, GM2 sequestration and the loss of lipid rafts lead to cell dysfunction and symptoms of NPC.

Flot2 acts as a novel mediator of podocyte injury in proteinuric kidney disease.

Podocyte injury is a common hallmark of chronic kidney disease (CKD). The podocin-nephrin complex localized in lipid rafts of podocyte is vital to reduce podocyte injury and proteinuria, however, the mechanism underlying its localization remains unclear. This study uncovers an important role of Flot2 in stabilizing the podocin-nephrin complex localized in lipid rafts. We first confirmed that Flot2 was expressed in podocyte and demenstrated that podocyte-specific Flot2 deletion worsen albuminuria, podocyte injury and glomerular pathology in LPS/ADR-induced nephropathy mouse models. Meanwhile, podocyte injury, albuminuria and pathologic aberrance were prevented in podocyte-specific Flot2 overexpression transgenic mice when challenged with LPS or ADR. Further found that Flot2 was vital to recruit podocin and nephrin into rafts and ameliorated podocyte injury. Flot2 and podocin directly interacted with each other via their SPFH domain. Meanwhile, we also showed that Flot-2 is a direct target of Krüppel-like factor (KLF15). Importanly, we observed that Flot2 was downregulated in renal biopsies from patients with podocytopathies and its expression negatively correlated with proteinuria and positively correlated with eGFR, indicating that Flot2 may be a novel therapeutic target for proteinuric kidney disease.

Flotillin-2 regulates epidermal growth factor receptor activation, degradation by Cbl-mediated ubiquitination, and cancer growth.

Epidermal growth factor receptor (EGFR) signaling is frequently dysregulated in various cancers. The ubiquitin ligase Casitas B-lineage lymphoma proto-oncogene (Cbl) regulates degradation of activated EGFR through ubiquitination and acts as an adaptor to recruit proteins required for trafficking. Here, we used stable isotope labeling with amino acids in cell culture mass spectrometry to compare Cbl complexes with or without epidermal growth factor (EGF) stimulation. We identified over a hundred novel Cbl interactors, and a secondary siRNA screen found that knockdown of Flotillin-2 (FLOT2) led to increased phosphorylation and degradation of EGFR upon EGF stimulation in HeLa cells. In PC9 and H441 cells, FLOT2 knockdown increased EGF-stimulated EGFR phosphorylation, ubiquitination, and downstream signaling, reversible by EGFR inhibitor erlotinib. CRISPR knockout (KO) of FLOT2 in HeLa cells confirmed EGFR downregulation, increased signaling, and increased dimerization and endosomal trafficking. Furthermore, we determined that FLOT2 interacted with both Cbl and EGFR. EGFR downregulation upon FLOT2 loss was Cbl dependent, as coknockdown of Cbl and Cbl-b restored EGFR levels. In addition, FLOT2 overexpression decreased EGFR signaling and growth. Overexpression of wildtype (WT) FLOT2, but not the soluble G2A FLOT2 mutant, inhibited EGFR phosphorylation upon EGF stimulation in HEK293T cells. FLOT2 loss induced EGFR-dependent proliferation and anchorage-independent growth. Lastly, FLOT2 KO increased tumor formation and tumor volume in nude mice and NSG mice, respectively. Together, these data demonstrated that FLOT2 negatively regulated EGFR activation and dimerization, as well as its subsequent ubiquitination, endosomal trafficking, and degradation, leading to reduced proliferation in vitro and in vivo.

TBL1X and Flot2 form a positive feedback loop to promote metastasis in nasopharyngeal carcinoma.

Metastasis is the main cause of death in patients with nasopharyngeal carcinoma (NPC). The molecular mechanisms underlying the metastasis of NPC remain to be elucidated. TBL1X has been shown abnormally expressed in diverse cancers. However, the role and mechanism of TBL1X in NPC remain unknown. Here, we showed TBL1X expression was significantly higher in metastatic NPC tissues compared to non-metastatic tissues and significantly correlated with TNM stage and metastasis of NPC patients. In addition, NPC patients with high TBL1X expression had a poor prognosis. TBL1X interacted with TCF4 to trans-activate Flot2 expression. TBL1X promoted NPC cell migration and invasion in vitro and in vivo through Flot2. Moreover, Flot2 increased the expression of TBL1X by upregulating c-myc, which was identified to be a positively regulatory transcription factor of TBL1X. TBL1X could restore the functional changes of NPC cells resulting from Flot2 alteration. TBL1X and Flot2 were positively correlated in NPC. Patients with high expression of both TBL1X and Flot2 possessed poorer overall survival (OS) and disease-free survival (DFS) compared to patients with high expression of any single one of the two proteins. Our findings demonstrate that TBL1X and Flot2 positively regulate each other to promote NPC metastasis, which provides novel potential molecular targets for NPC treatment.

N6-methyladenosine Demethylase FTO Induces the Dysfunctions of Ovarian Granulosa Cells by Upregulating Flotillin 2.

Polycystic ovarian syndrome (PCOS) is often accompanied by overweight/obesity and insulin resistance. The dysfunctions of ovarian granulosa cells (GCs) are closely linked with the pathogenesis of PCOS. Fat mass and obesity-associated gene (FTO), an N6-methyladenosine (m6A) demethylase, has been reported to be implicated in the risks and insulin resistance of PCOS. However, the roles of FTO in the development of GCs along with its m6A-related regulatory mechanisms are poorly defined. Cell proliferative ability was detected by MTT assay. Cell apoptotic rate was measured via flow cytometry. Insulin resistance was assessed by GLUT4 transport potential. The mRNA and protein levels of FTO and flotillin 2 (FLOT2) were determined by RT-qPCR and western blot assays, respectively. FLOT2 was screened out to be a potential FTO target through differential expression analysis for the GSE95728 dataset and target prediction analysis by POSTAR2 and STARBASE databases. The interaction between FTO and FLOT2 was analyzed by RNA immunoprecipitation (RIP) assay. The effect of FTO upregulation on FLOT2 m6A level was measured by methylated RIP (meRIP) assay. FLOT2 mRNA stability was examined by actinomycin D assay. FTO overexpression facilitated cell proliferation, hindered cell apoptosis, and induced insulin resistance in GCs. FTO promoted FLOT2 expression by reducing m6A level on FLOT2 mRNA and increasing FLOT2 mRNA stability. FLOT2 loss weakened the effects of FTO overexpression on cell proliferation/apoptosis and insulin resistance in GCs. FTO induced the dysfunctions of GCs by upregulating FLOT2, suggesting that FTO/FLOT2 might play a role in the pathophysiology of PCOS.

miR-34a-5p functions as a tumor suppressor in head and neck squamous cell cancer progression by targeting Flotillin-2.

While a number of therapeutic advances have been made in recent years, the overall survival of patients with head and neck squamous cell cancer (HNSCC) remains poor. MicroRNAs (miRNAs) are key drivers of oncogenic progression, with miR-34a-5p downregulation having been observed in many different tumor types. Here, we assessed the link between miR-34a-5p and HNSCC progression and the mechanistic basis for this relationship. Levels of miR-34a-5p in HNSCC tumors and cell lines were assessed via qPCR, after which we explored the functional importance of this miRNA in this oncogenic setting. Through luciferase reporter assays, the ability of miR-34a-5p to regulate flotillin-2 (FLOT-2) was further clarified. Overall, these analyses revealed that HNSCC tumors and cells exhibited marked miR-34a-5p downregulation that was linked to the progression of this tumor type. At a functional level, miR-34a-5p constrained the proliferation, migratory/invasive activity, and epithelial-mesenchymal transition induction in HNSCC cells. At the mechanistic level, miR-34a-5p was found to suppress FLOT-2 expression and to activate the MEK/ERK1/2 pathway. Overall, these results suggest that miR-34a-5p can function as a tumor suppressor miRNA in HNSCC owing to its ability to target FLOT-2, highlighting the promise of targeting this regulatory axis to treat HNSCC.

Flotillin-2 promotes cell proliferation via activating the c-Myc/BCAT1 axis by suppressing miR-33b-5p in nasopharyngeal carcinoma.

Previously, we elucidated the function of flotilin-2 (FLOT2) and branched-chain amino acid transaminase 1(BCAT1) in nasopharyngeal carcinoma (NPC). However, the relationship between FLOT2 and BCAT1 in promoting NPC progression remains unknown. Here, we observed that FLOT2 upregulated BCAT1 expression in NPC cells. Ectopic expression of BCAT1 significantly antagonized the inhibitory effects on NPC cell proliferation induced by FLOT2 depletion. Consequently, BCAT1 knockdown markedly inhibited the pro-proliferative effects of FLOT2 overexpression in NPC cells. FLOT2 expression was positively correlated with BCAT1 expression in NPC tissues and was inversely correlated with the prognosis of NPC patients. Mechanistically, FLOT2 maintains the expression level of c-Myc, a positive transcription factor of BCAT1, and subsequently promote BCAT1 transcription. FLOT2 inhibited miR-33b-5p in NPC cells and attenuated its inhibitory effects on c-Myc. Further, experimental validation of the function of the FLOT2/miR-33b-5p/c-Myc/BCAT1 axis in regulating NPC cell proliferation was performed. Our results revealed that FLOT2 promotes NPC cell proliferation by suppressing miR-33b-5p, to maintain proper levels of c-Myc, and upregulate BCAT1trancription. Therefore, the FLOT2/miR-33b-5p/c-Myc/BCAT1 axis is a potential therapeutic target for NPC.

FLOT2 upregulation promotes growth and invasion by interacting and stabilizing EphA2 in gliomas.

The expression and roles of FLOT2, especially for its underlying mechanism, in gliomas have been rarely revealed. In this study, upregulations of both FLOT2 and EphA2 in gliomas tissues were validated by immunohistochemistry (IHC) staining and Western blot. FLOT2 silencing notably inhibited the growth and invasion of gliomas cells. Simultaneously, FLOT2 depletion suppressed Akt and NF-κB activities, induced apoptosis, cell cycle arrest, and epithelial-mesenchymal transition (EMT) inhibition, demonstrated by expression alterations of key proteins of the above processes. Mechanistically, FLOT2 could maintain EphA2 stability viainteraction, and restoration of EphA2 could remarkably release the suppressive effects on gliomas cells induced by FLOT2 knockdown. Lastly, FLOT2 and EphA2, whose protein and mRNA levels are both positively correlated in gliomas, shows significant association with clinical characteristics like Ki67 intensity, p53 expression, and tumor stage in patients with gliomas. In conclusion, our results reveal the upregulation, oncogenic roles of FLOT2, and the corresponding underlying mechanism in gliomas, highlighting that the FLOT2-EphA2 axis is served as a promising therapeutic target for gliomas.

NFKB1-mediated downregulation of microRNA-106a promotes oxidative stress injury and insulin resistance in mice with gestational hypertension.

This study intended to investigate the role of NFKB1 in oxidative stress injury and insulin resistance in gestational hypertension (GH) mice. Following establishment of a GH mouse model by high-fat diet, NFKB1, miR-106a, and FLOT2 expression was detected in liver of mice. After NFKB1, miR-106a, and FLOT2 were altered in GH mice by lentiviral vector, oxidative stress markers in liver tissues were examined by colorimetry, and insulin resistance was assessed by fasting blood glucose and fasting insulin levels. Next, hepatocytes were isolated from GH mice and treated with miR-106a mimic, inhibitor or siRNA, followed by determination of hepatocyte apoptosis and the expression of inflammation- and apoptosis-related factors. Evaluation of the correlations among NFKB1, miR-106a, and FLOT2 were conducted. Liver of GH mice harbored NFKB1 and FLOT2 upregulation and miR-106a downregulation. miR-106a was transcriptionally inhibited by NFKB1, and negatively targeted FLOT2. Oxidative stress injury and insulin resistance in GH mice and apoptosis and inflammation of hepatocytes from GH mice were decreased after silencing NFKB1 or FLOT2 or overexpressing miR-106a. These findings provided evidence demonstrating the inhibitory effect of NFKB1 silencing on oxidative stress injury and insulin resistance in GH mice via miR-106a upregulation and FLOT2 downregulation.

Circ-FOXM1 contributes to cell proliferation, invasion, and glycolysis and represses apoptosis in melanoma by regulating miR-143-3p/FLOT2 axis.

BACKGROUND: Numerous literatures have demonstrated that circular RNAs (circRNAs) are involved in multiple types of tumors. However, the effects of circRNAs in melanoma are not very clear. In this study, we aimed to investigate the roles and mechanisms of circ-FOXM1 in melanoma. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to determine the expression of circ-FOXM1, microRNA-143-3p (miR-143-3p), and Flotillin 2 (FLOT2) mRNA. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, flow cytometry analysis, and transwell assay were employed to test cell proliferation, apoptosis, and invasion, respectively. The glucose consumption and lactate production were examined by specific kits. Western blot assay was utilized for the detection of hexokinase2 (HK2), pyruvate kinase isozyme type M2 (PKM2), and FLOT2. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were employed to verify the targeting association between miR-143-3p and circ-FOXM1 or FLOT2. A murine xenograft model was established to explore the effect of circ-FOXM1 in vivo. RESULTS: Circ-FOXM1 was elevated and miR-143-3p was reduced in melanoma tissues and cells. Circ-FOXM1 deficiency impeded cell proliferation, invasion, and glycolysis and facilitated cell apoptosis in melanoma in vitro and tumorigenesis in vivo. Circ-FOXM1 acted as a sponge of miR-143-3p and the impacts of circ-FOXM1 silencing on cell proliferation, apoptosis, invasion, and glycolysis were overturned by miR-143-3p deletion. Moreover, FLOT2 was a target gene of miR-143-3p and FLOT2 overexpression rescued the inhibitory effect of miR-143-3p on melanoma progression. CONCLUSION: Circ-FOXM1 facilitated the development of melanoma by upregulating FLOT2 through miR-143-3p.

Circ_001569 regulates FLOT2 expression to promote the proliferation, migration, invasion and EMT of osteosarcoma cells through sponging miR-185-5p.

Osteosarcoma (OS) is a common malignant tumor in the world. Circular RNAs are endogenous non-coding RNAs that have been linked to the development of cancer. However, the role of circ_001569 in OS progression is still unclear. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of circ_001569, microRNA-185-5p (miR-185-5p) and flotillin-2 (FLOT2). The abilities of cell proliferation, migration and invasion were evaluated by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and Transwell assays, respectively. Also, western blot analysis was performed to assess the levels of epithelial-mesenchymal transition (EMT)-related proteins and FLOT2 protein. Besides, the dual-luciferase reporter assay was used to verify the interactions among circ_001569, miR-185-5p and FLOT2. Circ_001569 expression was increased in OS tissues and cells, and its knockdown reduced the proliferation, migration, invasion and EMT of OS cells. MiR-185-5p could interact with circ_001569. Inhibition of miR-185-5p could recover the suppression effects of silenced-circ_001569 on the proliferation and metastasis of OS cells. Furthermore, FLOT2 was a target of miR-185-5p. Overexpressed FLOT2 could restore the inhibition effects of miR-185-5p mimic on the proliferation and metastasis of OS cells. Also, FLOT2 expression was regulated by circ_001569 and miR-185-5p. In addition, circ_001569 knockdown also reduced the OS tumor growth in vivo. Circ_001569 might act as an oncogene in OS progression by regulating the miR-185-5p/FLOT2 axis, which provided a reliable new approach for the treatment of OS patients.

The Flot2 component of the lipid raft changes localization during neural differentiation of P19C6 cells.

BACKGROUND: Flotillin-2 (Flot2) is a lipid raft scaffold protein that is thought to be related to neural differentiation. Flot2 is phosphorylated by Fyn, a Src kinase, and causes raft-dependent endocytosis; however, the exact role of Flot2 in neural differentiation remains unclear. To reveal the roles of lipid raft-associated proteins during neural differentiation, we tried to analyze the expression and localization. RESULTS: In this study, we found that the expression levels of the Flot2 and Fyn proteins increased in whole-cell lysates of P19C6 cells after neural differentiation. In addition, sucrose density fractionation and immunofluorescence experiments revealed an increase in the localization of Flot2 and Fyn to lipid rafts after neural differentiation. We also found that Fyn partially colocalized with Flot2 lipid rafts in neural cells. CONCLUSION: The observed distribution of Fyn and level of inactivated Fyn and/or c-Src in detergent-resistant membrane (DRM) fractions suggests that the amount of activated Fyn might increase in DRM fractions after neural differentiation. Overall these findings suggest that Flot2 lipid rafts are associated with Fyn, and that Fyn phosphorylates Flot2 during neural differentiation of P19C6 cells.

The study of mechanism of miR-34c-5p targeting FLOT2 to regulate proliferation, migration and invasion of osteosarcoma cells.

Objective: Osteosarcoma is one of the most common malignancies in children and adolescents. Studies have shown that miR-34c-5p is involved in the progression of various cancers. To explore the effects of miR-34c-5p on the proliferation, migration and invasion of osteosarcoma cells and its potential mechanism. Methods: qRT-PCR was used to detect the expression levels of miR-34c-5p and FLOT2 mRNA in osteosarcoma tissues and cells. Western Blot was used to detect protein expression. MTT assay used to detect cell viability. Transwell was used to detect cell migration and invasion in each group. Dual luciferase reporter gene assay was used to detect luciferase activity. Results: The expression of miR-34c-5pwas significantly decreased in osteosarcoma tissues and cells and the expression level of FLOT2 mRNA was significantly increased. Overexpression of miR-34c-5p and inhibition of FLOT2 inhibited the proliferation, migration and invasion of osteosarcoma cells and inhibited the expression of Cyclin D1, MMP-2 and MMP-9 proteins and promoted the expression of p21 protein. miR-34c-5p targeted to regulate the expression of FLOT2. Overexpression of FLOT2 reversed the inhibitory effect of miR-34c-5p overexpression on proliferation, migration and invasion of osteosarcoma cell lines. Conclusion: miR-34c-5p can inhibit the proliferation, migration and invasion of osteosarcoma cells. The mechanism may be related to targeting FLOT2, which will provide a new target for the prevention and treatment of osteosarcoma.

MicroRNA-351 eases insulin resistance and liver gluconeogenesis via the PI3K/AKT pathway by inhibiting FLOT2 in mice of gestational diabetes mellitus.

Gestational diabetes mellitus (GDM) is known as different degree glucose intolerance that is initially identified during pregnancy. MicroRNAs (miRs) may be a potential candidate for treatment of GDM. Herein, we suggested that miR-351 could be an inhibitor in the progression of GDM via the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) pathway. Microarray analysis was used to identify differentially expressed genes and predict miRs regulating flotillin 2 (FLOT2). Target relationship between miR-351 and FLOT2 was verified. Gestational diabetes mellitus mice were treated with a series of mimic, inhibitor and small interfering RNA to explore the effect of miR-351 on insulin resistance (IR), cell apoptosis in pancreatic tissues and liver gluconeogenesis through evaluating GDM-related biochemical indexes, as well as expression of miR-351, FLOT2, PI3K/AKT pathway-, IR- and liver gluconeogenesis-related genes. MiR-351 and FLOT2 were reported to be involved in GDM. FLOT2 was the target gene of miR-351. Gestational diabetes mellitus mice exhibited IR and liver gluconeogenesis, up-regulated FLOT2, activated PI3K/AKT pathway and down-regulated miR-351 in liver tissues. Additionally, miR-351 overexpression and FLOT2 silencing decreased the levels of FLOT2, phosphoenolpyruvate carboxykinase, glucose-6-phosphatase, fasting blood glucose, fasting insulin, total cholesterol, triglyceride, glyeosylated haemoglobin and homeostasis model of assessment for IR index (HOMA-IR), extent of PI3K and AKT phosphorylation, yet increased the levels of HOMA for islet ß-cell function, HOMA for insulin sensitivity index and glucose transporter 2 expression, indicating reduced cell apoptosis in pancreatic tissues and alleviated IR and liver gluconeogenesis. Our results reveal that up-regulation of miR-351 protects against IR and liver gluconeogenesis by repressing the PI3K/AKT pathway through regulating FLOT2 in GDM mice, which identifies miR-351 as a potential therapeutic target for the clinical management of GDM.

MicroRNA-485-5p suppresses the proliferation, migration and invasion of small cell lung cancer cells by targeting flotillin-2.

This study is aimed to elucidate the mechanisms underlying the role of miR-485-5p in small cell lung cancer (SCLC). The expression of miR-485-5p were quantified with real time quantitative PCR and it was found that the level of miR-485-5p was lower in SCLC tissues than normal tissues. In cultured SCLC cell lines, overexpression of miR-485-5p reduced cell proliferation, migration, and invasion in vitro, whereas knockdown of miR-485-5p performed contrary. FLOT2 expression was obviously upregulated and negatively correlated with miR-485-5p expression level in SCLC tissues. Overexpression of miR-485-5p significantly inhibited the protein expression of flotillin-2 (FLOT2) in cultured SCLC cells. Luciferase reporter assay confirmed that FLOT2 was a direct target of miR-485-5p in SCLC cells. It is concluded that miR-485-5p, as a tumor suppressor, inhibits the growth and metastasis in SCLC by targeting FLOT2. Upregulation of miR-485-5p expression may be an attractive strategy for SCLC therapy.

Flot2 targeted by miR-449 acts as a prognostic biomarker in glioma.

Flotillin-2 (FLOT2) was reported as oncogene and involves in the pathogenic process of several cancers, yet the precise mechanism of FLOT2 in glioma is still limited. In this study, we demonstrated that FLOT2 expression levels were greatly upregulated in glioma tissues and cell lines, and the FLOT2 expression in glioma tissue was markedly associated with tumour stage and size. Overexpression of FLOT2 was correlated with poor prognosis of glioma patients. The functional assay revealed that silenced FLOT2 repressed the viability, migration, and invasion of glioma cells. And then, we detected the relationship between miR-449 and FLOT2. Luciferase reporter assay and Western blot results showed that miR-449 directly binding the 3'UTR sequence of FLOT2 and regulated FLOT2 expression in glioma cells. Finally, we detected the expression levels of miR-449 in glioma tissue and cell lines and found that miR-449 was significantly downregulated in glioma tissues and cell lines. In conclusion, we demonstrated that overexpression FLOT2 was associated with poor prognosis of glioma patients and involved in the progression of glioma, identifying a novel prognostic biomarker and therapeutic target for glioma progression.