Oncogenic and Immunological Roles of FRS2 and its Potential Value in Retroperitoneal Liposarcoma: from Bioinformatics Analysis to Clinicopathological Evidence.

The plasma membrane is not homogeneous but contains specific subcompartments characterized by their unique lipid and protein composition. Based on their enrichment in various signaling molecules, these membrane microdomains are recognized to be sites of localized signal transduction for a number of extracellular stimuli. We have previously shown that fibroblast growth factor-2 (FGF2) induced a specific signaling response within a lipid raft membrane microdomain in human neuroblastoma cells characterized by the tyrosine phosphorylation of a p80 phosphoprotein. Herein, we show that this protein is the signaling adaptor FRS2 and that it is localized exclusively to lipid rafts in vitro and in vivo. We have examined how the tyrosine phosphorylation and serine-threonine phosphorylation of FRS2 within lipid rafts affect the response of cells to FGF2 signaling. Our data suggest that activation of protein kinase C, Src family kinases, and MEK1/2 are involved in regulating serine-threonine phosphorylation of FRS2, which can indirectly affect FRS2 phosphotyrosine levels. We also show that Grb2 is recruited to lipid rafts during signaling events and that activation of MEK1/2 by different mechanisms within lipid rafts may lead to different cellular responses. This work suggests that compartmentalized signaling within lipid rafts may provide a level of specificity for growth factor signaling.

BackgroundThe fibroblast growth factor receptor substrate 2 (FRS2) gene is located close to MDM2 and CDK4 within the 12q13-15 chromosomal region. FRS2 gene was recently found to be consistently amplified in atypical lipomatous tumor (ALT)/well-differentiated liposarcoma (WDL) and dedifferentiated liposarcoma (DDL), suggesting the detection of FRS2 amplification could be a diagnostic tool for ALT/WDL/DDLs. However, the expression of FRS2 protein and diagnostic value of FRS2 immunohistochemistry (IHC) has not been evaluated in a large cohort of ALT/WDL/DDLs.MethodsA SNOMED search of hospital surgical pathology files from January 2007 to July 2020 identified 182 ALT/WDL/DDLs with available materials. FRS2 fluorescence in situ hybridization (FISH) and IHC were performed on 182 ALT/WDL/DDLs and 64 control samples. The expression of FRS2 was also compared with that of classic immunomarkers (MDM2 and CDK4) of this tumor entity.ResultsThis study included 91 ALT/WDLs and 91 DDLs. The FISH results showed 172 of 182 (94.5%) cases were FRS2-amplified, and 10 cases were FRS2-nonamplified. Immunostaining results showed 171 (94.0%) ALT/WDL/DDLs were positive for FRS2 and 11 cases (6.0%) were FRS2-immunonegative. In 172 FRS2-amplified cases, 166 (96.5%) were FRS2-immunopositive, and 6 (3.5%) were negative. Among 10 FRS2-nonamplified ALT/WDL/DDL cases, 5 cases were FRS2-immunonegative, and 5 tumors displayed 1+ staining for this marker. In 64 control cases, none of them exhibited FRS2 amplification. Forty-seven (73.5%) control cases were negative for FRS2 immunostaining, while 17 cases (26.5%) were FRS2-immunopositive. Fifteen of these false positive samples (15/17, 88.2%) showed 1+ positivity and only 2 cases (2/17, 11.8%) displayed 2+ positivity. In ALT/WDL/DDLs, the sensitivity of FRS2 immunostaining was slightly lower than MDM2 (FRS2 vs. MDM2: 94.0% vs 100.0%) and CDK4 (FRS2 vs. CDK4: 94.0% vs 97.0%). However, the specificity of FRS2 (73.5%) was slightly higher than that of MDM2 (67.8%) and CDK4 (64.4%).ConclusionThis study indicated that FRS2 IHC had relatively good consistency with FRS2 FISH, suggesting that FRS2 immunostaining could be utilized as an additional screening tool for the diagnosis of ALT/WDL/DDL. It must be emphasized that MDM2/CDK4/FRS2 especially MDM2 FISH remains the gold standard and the most recommended method to diagnose this entity.

BackgroundAdaptor proteins bridge the gap between cell surface receptors and their downstream signaling elements. The clinicopathological and prognostic values of adaptor proteins remain poorly understood. The purpose of the present study was to explore the expression and prognostic value of three adaptor proteins: GRB2-associated binding protein 2 (GAB2), CRK-like protein (CRKL) and fibroblast growth factor receptor substrate 2 (FRS2) in pancreatic ductal adenocarcinoma (PDAC).MethodsThe expression of GAB2, CRKL, and FRS2 in 77 formalin fixed paraffin embedded (FFPE) samples from 77 PDAC patients, along with three paired fresh PDAC and matched normal tissues from 3 PDAC patients was analyzed by immunohistochemistry and western blot, respectively. The association between the expression of the three proteins and the clinicopathological factors of PDAC was assessed by χ2 test. The correlation between the expression levels of the three proteins was analyzed by Spearman rank correlation analyses; Kaplan-Meier survival analyses were also performed.ResultsIHC was successful in 75, 76, and 77 cases for GAB2, CRKL, and FRS2, respectively. Of which, the positive rate of GAB2, CRKL, and FRS2 protein expression was 40.00% (30/75), 53.95% (41/76) and 35.06% (27/77), respectively. The positive rate of GAB2, CRKL and FRS2 co-expression was 16.88% (13/77). Though there was no association between GAB2 expression, CRKL expression, FRS2 expression, GAB2/CRKL/FRS2 co-expression and the clinicopathological parameters of PDAC, positive correlations were observed between the expressions of the three proteins. Further, univariate survival analysis showed that positive expression of GAB2, CRKL and FRS2 and co-expression of GAB2/CRKL/FRS2 of PDAC predicted poor clinical outcomes, and multivariate survival analysis suggested that positive expression of GAB2 and positive co-expression of GAB2/CRKL/FRS2 were independent prognostic factors for disease-free survival (DFS) and overall survival (OS), respectively.ConclusionIn conclusion, GAB2, CRKL, and FRS2 may be potential prognosticators and therapeutic targets for PDAC patients.

The aim of this study was to investigate the expression level of fibroblast growth factor receptor substrate 2 (FRS2) in tissues of patients with primary retroperitoneal liposarcoma (PRPLS) and its correlation with recurrence and prognosis. The pathological specimens, medical records, and follow-up information of patients with PRPLS who underwent radical surgery for the first time in our hospital from January 2013 to December 2016 were retrospectively analyzed. FRS2 protein expression in tissues was determined by immunohistochemistry staining, and the FRS2 protein positive rates in patients with different clinicopathological features were compared. Factors influencing patients' recurrence and survival were determined using the multivariate Cox stepwise regression model. This research enrolled 87 patients with PRPLS, with the number of cases presenting FRS2 protein positive rate and positive rate in pathological tissues accounting for 62.07% (54/87) and 37.93% (33/87), respectively. The positive expression of FRS2 protein varied markedly among patients with different pathological types, FNCC, LCC grade, number of tumors, positive margin, and recurrence and metastasis (with vs. without) (all p<0.05). The 87 patients were followed up for 3.5-102 months (median, 27.5 months), with a postoperative 5-year overall disease-free survival (DFS) rate of 17.24% [median progression-free survival (PFS): 24.7 months] and a 5-year overall survival (OS) rate of 44.83% (median OS: 47.3 months). Kaplan-Meier survival curves revealed significantly shorter PFS and OS in patients with positive FRS2 protein expression vs. those with negative FRS2 protein expression (χ2=6.396, 5.032, p<0.05). According to the univariate analysis, the 5-year overall DFS rate varied significantly among patients with different pathological types, Fédération Nationale des Centres De Lutte Contre le Cancer (FNCLCC) grades, number of tumors, positive margin, and FRS2 protein expression (all p<0.05). Pathological type, FNCLCC grading, tumor number, recurrence and metastasis, positive margin, and FRS2 protein expression were significantly correlated with the 5-year OS rate of patients (all p<0.05). Furthermore, pathological type, FNCLCC grading, multiple tumors, positive margin, and FRS2 protein expression were identified by multivariate Cox regression analysis to be independent factors that affected patients' 5-year DFS and OS rates (all p<0.05), and that relapsed and metastasized patients had a 4.586-fold risk of death than those without recurrence and metastasis. FRS2 shows a high positive rate in the tissues of PRPLS patients and is significantly related to the prognostic recurrence and survival of patients, with potential value in judging the prognosis of patients.

Background: There are two members – FRS2α and FRS2β – in the fibroblast growth factor receptor substrate 2 (FRS2) family of docking/scaffolding adaptor proteins. These proteins function downstream of certain kinds of receptor tyrosine kinases (RTKs) that are important for tumorigenesis. FRS2α acts as a control centre for fibroblast growth factor receptor signalling and encourages tumorigenesis, while FRS2β regulates EGFR signalling negatively, and might have a tumour suppressive role. Therefore, both proteins could be good therapeutic targets for the treatment of cancer. Objective: To examine the physiological and pathological roles of FRS2, especially in cancer, and describe their potential value as therapeutic targets. Methods: A review of relevant literature. Results/conclusions: Although it is still difficult to develop small compounds to modify functions of FRS2 adaptor proteins, such compounds may be useful as the next generation of molecular targeting drugs. Combination therapy with RTK-targeting drugs and FRS2-targeting drugs may be useful for cancer treatment in the near future.

Atherosclerosis (AS) is a pivotal pathological basis of cardiovascular and cerebrovascular diseases, and circular RNAs (circRNAs) has been disclosed to exert a vital part in the progression of AS. However, the functions of circ_0004872 in the progression of AS is indistinct. In this context, we aimed to elucidate the role of circ_0004872 and the potential mechanism in AS. The level of circ_0004872, miR-424-5p and fibroblast growth factor receptor substrate 2 (FRS2) was detected using quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was monitored by Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine (EDU) assays. The invasion and migration capabilities of VSMCs were tested by transwell assays and wound-healing assay, respectively. Western blot was adopted to check the protein levels of CyclinD1, Vimentin and FRS2. Dual-luciferase reporter and RNA immunoprecipitation assay were executed to manifest the interaction between miR-424-5p and circ_0004872 or FRS2. The level of circ_0004872 was increased in the serum samples of AS patients and ox-LDL-exposed VSMCs. Ox-LDL exposure triggered cell proliferation, invasion and migration ability of VSMCs. depletion of circ_0004872 partly weakened ox-LDL-mediated effects in VSMCs. Mechanistically, circ_0004872 functioned as a sponge of miR-424-5p, and miR-424-5p inhibition partly alleviated circ_0004872 deficiency-mediated influences in VSMCs. Additionally, miR-424-5p interacted with FRS2, and miR-424-5p constrained dysfunction in ox-LDL-stimulated VSMCs via reducing FRS2 level. Notably, circ_0004872 functioned as a sponge of miR-424-5p to elevate FRS2 expression. Circ_0004872 accelerated ox-LDL-induced damage via mediating miR-424-5p/FRS2 axis.

Brain-derived neurotrophic factor (BDNF) and other neurotrophins induce a unique prolonged activation of mitogen-activated protein kinase (MAPK) compared with growth factors. Characterization and kinetic and spatial modeling of the signaling pathways underlying this prolonged MAPK activation by BDNF will be important in understanding the physiological role of BDNF in many complex systems in the nervous system. In addition to Shc, fibroblast growth factor receptor substrate 2 (FRS2) is required for the BDNF-induced activation of MAPK. BDNF induces phosphorylation of FRS2. However, BDNF does not induce phosphorylation of FRS2 in cells expressing a deletion mutant of TrkB (TrkBDeltaPTB) missing the juxtamembrane NPXY motif. This motif is the binding site for SHC. NPXY is the consensus sequence for phosphotyrosine binding (PTB) domains, and notably, FRS2 and SHC contain PTB domains. This NPXY motif, which contains tyrosine 484 of TrkB, is therefore the binding site for both FRS2 and SHC. Moreover, the proline containing region (VIENP) of the NPXY motif is also required for FRS2 and SHC phosphorylation, which indicates this region is an important component of FRS2 and SHC recognition by TrkB. Previously, we had found that the phosphorylation of FRS2 induces association of FRS2 and growth factor receptor binding protein 2 (Grb2). Now, we have intriguing data that indicates BDNF induces association of the SH2 domain containing protein tyrosine phosphatase, Shp2, with FRS2. Moreover, the PTB association motif of TrkB containing tyrosine 484 is required for the BDNF-induced association of Shp2 with FRS2 and the phosphorylation of Shp2. These results imply that FRS2 and Shp2 are in a BDNF signaling pathway. Shp2 is required for complete MAPK activation by BDNF, as expression of a dominant negative Shp2 in cells attenuates BDNF-induced activation of MAPK. Moreover, expression of a dominant negative Shp2 attenuates Ras activation showing that the protein tyrosine phosphatase is required for complete activation of MAPKs by BDNF. In conclusion, Shp2 regulates BDNF signaling through the MAPK pathway by regulating either Ras directly or alternatively, by signaling components upstream of Ras. Characterization of MAPK signaling controlled by BDNF is likely to be required to understand the complex physiological role of BDNF in neuronal systems ranging from the regulation of neuronal growth and survival to the regulation of synapses.

Long non-coding RNAs (lncRNAs) play crucial roles in human diseases. However, the detailed role of lncRNAs in hypertrophic scar fibroblasts (HSFs) is inadequately understood. This study aimed to investigate the potential role of lncRNA nuclear enriched abundant transcript 1 (NEAT1) in hypertrophic scarring. Expression of lncRNAs, miRNAs, and genes were detected by polymerase chain reaction; protein expression was evaluated using western blotting. Cellular function was determined using the CCK-8 assay. The interaction between microRNA (miR)-29-3p and NEAT1 or fibroblast growth factor receptor substrate 2 (FRS2) was verified by luciferase and RNA pull-down assays. The results showed that NEAT1 was overexpressed in the hypertrophic dermis and in HSFs. However, knockdown of NEAT1 suppressed the proliferation and extracellular matrix (ECM) production of HSFs. Moreover, NEAT1 functioned as a competing endogenous RNA to upregulate FRS2 by sponging miR-29-3p. Downregulation of miR-29-3p or overexpression of FRS2 antagonized the effects of NEAT1 knockdown and promoted HSF proliferation and ECM release. In conclusion, NEAT1 knockdown protected against hypertrophic scarring by modulating the miR-29-3p/FRS2 axis, which is a viable target in scar treatment.

The components of the extracellular signal-regulated kinase (ERK) pathway are involved in the regulation of epididymal cellular processes. Interestingly, our previous studies showed that there are two different activity levels of the ERK pathway components in the epididymal epithelium: a basal level in most regions and a higher level in the differentiated initial segment (IS). In this study we analyzed the role of fibroblast growth factor receptor substrate 2 (FRS2) in the regulation of these two levels. Two mouse models were generated. In the first model, Frs2 was deleted from epithelial cells of most epididymal regions except for the IS from the embryonic period onward. Loss of Frs2 dampened the basal activity level of the ERK pathway components, which resulted in an increase in apoptosis along the epididymal duct. This was observed during the period when FRS2 expression level was highest in wild-type epididymides. In the second model, Frs2 was deleted from the proximal epididymal epithelium from Postnatal Day 17 onward. Most of the epididymides in this model exhibited normal morphology. Loss of Frs2 in these epididymides did not affect the high activity level of the ERK pathway components in the IS. However, a subgroup of epididymides in the second model showed increased apoptosis which resulted in an abnormally shaped proximal region or development of granulomas. Therefore, data from these two models showed that FRS2 played different roles in the regulation of two activity levels of the ERK pathway components in the epididymis.

Brain-derived neurotrophic factor (BDNF) promotes neuronal survival. Gaining an understanding of how BDNF, via the tropomyosin-related kinase B (TRKB) receptor, elicits specific cellular responses is of contemporary interest. Expression of mutant TrkB in fibroblasts, where tyrosine 484 was changed to phenylalanine, abrogated Shc association with TrkB, but only attenuated and did not block BDNF-induced phosphorylation of mitogen-activated protein kinase (MAPK). This suggests there is another BDNF-induced signaling mechanism for activating MAPK, which compelled a search for other TrkB substrates. BDNF induces phosphorylation of fibroblast growth factor receptor substrate 2 (FRS2) in both fibroblasts engineered to express TrkB and human neuroblastoma (NB) cells that naturally express TrkB. Additionally, BDNF induces phosphorylation of FRS2 in primary cultures of cortical neurons, thus showing that FRS2 is a physiologically relevant substrate of TrkB. Data are presented demonstrating that BDNF induces association of FRS2 with growth factor receptor-binding protein 2 (GRB2) in cortical neurons, fibroblasts, and NB cells, which in turn could activate the RAS/MAPK pathway. This is not dependent on Shc, since BDNF does not induce association of Shc and FRS2. Finally, the experiments suggest that FRS2 and suc-associated neurotrophic factor-induced tyrosine-phosphorylated target are the same protein.

Wilms' tumor (WT) is the most common malignant renal tumor in children. MicroRNAs (MiRNAs) function in the progression of various cancers. Recent reports have reported that miR-140-5p and miR-92a-3p are dysregulated in WT tissues, but the potential mechanisms of the two miRNAs in modulating WT progression are still poorly understood. Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was conducted to detect the expression levels of miR-140-5p, miR-92a-3p, and fibroblast growth factor receptor substrate 2 (FRS2) in WT tissues and cells, as well as matched controls. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and flow cytometry assay were employed to check cell proliferation and apoptosis, respectively. The abilities of cell migration and invasion were evaluated by transwell assay. The protein level of FRS2 in samples was measured by Western blot. The starBase was used to predict the binding sites between FRS2 and miR-140-5p or miR-92a-3p and the Dual-Luciferase reporter assay was performed to verify the interaction. Xenograft tumor model was established to investigate the biological roles of the two miRNAs in WT in vivo. The levels of miR-140-5p and miR-92a-3p were significantly downregulated in WT tissues and cells, while the expression of FRS2 was significantly upregulated. The two miRNAs both inhibited proliferation, migration, invasion, and induced apoptosis of WT cells. Besides, FRS2 was a target of the two miRNAs and its overexpression reversed the effects of the two miRNAs-mediated suppression on WT progression. Moreover, the upregulation of the two miRNAs repressed tumor growth in vivo. MiR-140-5p and miR-92a-3p attenuated the aggressive progression of WT via targeting FRS2.

Circular RNAs (circRNAs) have been reported to play vital roles in atherosclerosis. However, the precise roles of circUBR4 in atherosclerosis remain unclear. The purpose of this study is to investigate the regulatory roles of circUBR4 in atherosclerosis. The expression levels of circUBR4, miR-185-5p, and Fibroblast growth factor receptor substrate 2 (FRS2) were analyzed by real-time quantitative polymerase chain reaction (RT-qPCR) assay. Human vascular smooth muscle cells (VSMCs) were treated with oxidized low-density lipoprotein (ox-LDL) to mimic atherosclerosis condition in vitro. Cell proliferation was determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-2H-tetrazol-3-ium bromide (MTT), colony-forming, and 5-ethynyl-2'-deoxyuridine (EdU) assays. Wound healing and transwell assays were used to assess cell migration. The interaction relationship between miR-185-5p and circUBR4 or FRS2 was confirmed by dual-luciferase reporter and RNA pull-down assays. CircUBR4 was overexpressed in atherosclerosis patients and VSMCs treated with ox-LDL, and the knockdown of circUBR4 abolished ox-LDL-induced enhanced effects on the proliferation and migration of VSMCs. MiR-185-5p, interacted with FRS2, was a target of circUBR4 in VSMCs. The silencing of miR-185-5p reversed the effects caused by circUBR4 knockdown on ox-LDL-induced VSMCs. In addition, overexpression of miR-185-5p suppressed the proliferation and migration of VSMCs by targeting FRS2. CircUBR4 contributed to ox-LDL-induced VSMC proliferation and migration through up-regulating FRS2 via miR-185-5p.

The accumulation of vascular smooth muscle cells (VSMCs) is considered to play important roles in atherosclerosis (AS) development and progression. Circ_0002984 was found to be increased in oxidized low-density lipoprotein (ox-LDL) human VSMCs (HVSMCs). However, the function and mechanism of circ_0002984 in VSMC dysfunction remain unknown. In this study, the expression of circ_0002984, microRNA (miR)-379-5p, and fibroblast growth factor receptor substrate 2 (FRS2) was detected using quantitative real-time polymerase chain reaction and western blot. Cell proliferation, cell cycle, migration, and invasion were detected using Cell Counting Kit-8, flow cytometry, and transwell assays. The binding interaction between miR-379-5p and circ_0002984 or FRS2 was confirmed by the dual-luciferase reporter assay. Collectively, this study found that circ_0002984 was elevated in platelet-derived growth factor type bb (PDGF-bb)-induced HVSMCs. Circ_0002984 knockdown abrogated PDGF-bb-induced proliferation, migration, and invasion in HVSMCs. Mechanistically, circ_0002984 was confirmed to target miR-379-5p, and miR-379-5p upregulation reversed the protective effects of circ_0002984 knockdown on PDGF-bb-induced HVSMCs. Besides, when FRS2 was a target of miR-379-5p, miR-379-5p restoration abolished PDGF-bb-evoked HVSMC dysfunction, which was attenuated by the overexpression of FRS2. Moreover, circ_0002984 could regulate FRS2 expression through sponging miR-379-5p in HVSMCs. Collectively, these results demonstrated that circ_0002984 promoted PDGF-bb-induced VSMC proliferation, migration, and invasion through the regulation of miR-379-5p/FRS2 axis, suggesting a new insight into the pathogenesis of AS and the potential application of circ_0002984 in AS treatment.

Vascular endothelial growth factor (VEGF) activates endothelial cells, in part, by interacting with the kinase insert domain-containing receptor (KDR) receptor tyrosine kinase. Although progress has been made in the identification of cell-signaling proteins that participate in the VEGF-induced response, questions remain concerning the molecular interactions that allow coupling of receptor activation with an increased cellular response. Evidence is provided in this manuscript that indicates a role for the fibroblast growth factor receptor substrate 2 (FRS2) in VEGF-induced signal transduction. VEGF treatment of human umbilical vein endothelial cells (HUVECs) and KDR-transfected porcine aortic endothelial cells leads to the rapid tyrosine phosphorylation of FRS2. FRS2 is associated constitutively with KDR, and VEGF treatment has no effect on this interaction. VEGF treatment of KDR-expressing cells leads to the recruitment of Nck, p21-activated kinase, Crk, Grb2, and protein kinase C l to FRS2. The ability of FRS2 to recruit cell-signaling proteins to the cell is significant because it provides a mechanism for enhancing the repertoire of VEGF-induced signaling pathways.

Circular RNA (circRNAs) has been confirmed to participate in atherosclerosis (AS) progression. However, the role and mechanism of hsa_circ_0032389 in AS process still need to be further revealed. This study evaluates the role and mechanism of hsa_circ_0032389 in AS process. Platelet-derived growth factor-BB (PDGF-BB) was used to induce human aortic vascular smooth muscle cells (HA-VSMCs). The expression levels of hsa_circ_0032389, microRNA (miR)-513a-5p, and fibroblast growth factor receptor substrate 2 (FRS2) were examined by quantitative real-time PCR. Cell proliferation and migration were analyzed using cell counting kit 8 assay, flow cytometry, EdU assay, transwell assay, and wound healing assay. Protein expression was assessed using western blot analysis. Dual-luciferase reporter and RIP assays were used to confirm RNA interaction. Hsa_circ_0032389 was overexpressed in PDGF-BB-induced HA-VSMCs, and its downregulation inhibited HA-VSMC viability, cell cycle, EdU positive cell rate, migratory cell number, and wound closure rate under PDGF-BB treatment. The luciferase activity of hsa_circ_0032389wt could be reduced by miR-513a-5p mimic, and both hsa_circ_0032389 and miR-513a-5p were enriched in anti-Ago2, confirming that miR-513a-5p could be sponged by hsa_circ_0032389. MiR-513a-5p inhibitor reversed the effect of hsa_circ_0032389 knockdown on PDGF-BB-induced HA-VSMC viability, cell cycle, EdU positive cell rate, migratory cell number, and wound closure rate. Moreover, the luciferase activity of FRS2wt was reduced by miR-513a-5p mimic, and both FRS2 and miR-513a-5p were enriched in anti-Ago2, verifying that FRS2 was targeted by miR-513a-5p. MiR-513a-5p suppressed PDGF-BB-induced HA-VSMC viability, cell cycle, EdU positive cell rate, migratory cell number, and wound closure rate by targeting FRS2. Our results indicated that hsa_circ_0032389 enhanced PDGF-BB-induced HA-VSMC proliferation and migration via regulating miR-513a-5p/FRS2 axis.