SFRP5 Partially Inhibits the Proliferation and Migration of Airway Smooth Muscle Cells in Children with Asthma by Regulating the Wnt/β-Catenin Signaling Pathway

BACKGROUND

Childhood asthma is a chronic inflammatory disease of the respiratory tract characterized by bronchial inflammation, airway hyperresponsiveness, airflow disorder, and obstruction. Secreted frizzled-related protein 5 (SFRP5) may be associated with respiratory inflammatory diseases. This study investigated the effect of SFRP5 on human airway smooth muscle cells (HASMCs) to provide new ideas for treating asthma.

METHODS

A total of 30 children with asthma and 30 children who had a physical examination at the same time were selected and divided into asthma and healthy groups. Serum SFRP5 levels were determined by enzyme-linked immunosorbent assay (ELISA) and real-time quantitative polymerase chain reaction (RT-qPCR). Lipofectamine 2000™ regent was used to transfect the SFRP5 overexpression plasmid (pc-SFRP5) or corresponding negative control (pc-NC) into HASMCs. HASMCs were treated with 10 μg/L platelet-derived growth factor-BB (PDGF-BB), which is an inducer to mimic the asthma-like condition at the cellular level of childhood asthma. HASMCs were divided into control, PDGF-BB (PDGF-BB treatment), PDGF-BB+pc-NC (pc-NC transfection and PDGF-BB treatment), and PDGF-BB+pc-SFRP5 (pc-SFRP5 transfection and PDGF-BB treatment) groups. Cell proliferation was measured by 5-ethynyl-2'-deoxyuridine (EdU) and cell counting kit-8 (CCK-8) assay. Cell migration was detected by Transwell assay. The protein expression was detected by western blot.

RESULTS

Serum SFRP5 expression in the asthmatic group was decreased versus the healthy group (p < 0.0001). Induction of PDGF-BB decreased SFRP5 expression in HASMCs (p < 0.01). SFRP5 expression in the pc-SFRP5 group was increased (p < 0.01). The proliferation and migration of HASMCs increased after PDGF-BB treatment (p < 0.001, p < 0.0001), indicating that the asthma model was successfully inducted in vitro. Moreover, the expression of β-catenin, cellular-myelocytomatosis viral oncogene (c-Myc), and cyclinD1 proteins in HASMCs increased after PDGF-BB treatment (p < 0.0001). SFRP5 overexpression partly inhibited PDGF-BB-induced proliferation, migration, and expressions of β-catenin, c-Myc, and cyclinD proteins in HASMCs (p < 0.01, p < 0.001, p < 0.0001).

CONCLUSIONS

Serum SFRP5 expression decreases in children with asthma. SFRP5 overexpression partially inhibits PDGF-BB-induced HASMC proliferation and migration by regulating the wingless-type mouse mammary tumor virus (MMTV) integration site family (Wnt)/β-catenin pathway.

Concentration of Secreted Frizzled-Related Proteins (SFRPs) in Non-Small Cell Lung Carcinoma Subtypes-A Preliminary Study

Non-small cell lung carcinoma (NSCLC) is the most common lung cancer worldwide. Secreted frizzled-related proteins (SFRPs) are important tumour suppressors and antagonists of the Wnt signalling pathway, which is linked with cancer development. The aim of this study was to evaluate the concentrations of SFRP1, SFRP2, and SFRP5 proteins in tumour and non-tumour (NT) samples obtained from 65 patients with primary NSCLC. An enzyme-linked immunosorbent assay (ELISA) was used to measure the concentrations of SFRPs in the tissue homogenates. A significantly lower SFRP2 protein concentration was found in the total NSCLC tumour samples and the following NSCLC subtypes: squamous cell carcinoma (SCC) and adenocarcinoma (AC) (p > 0.05, p = 0.028 and p = 0.001, respectively). AC tumour samples had a higher SFRP1 level than NT samples (p = 0.022), while the highest SFRP1 concentration was found in NSCLC samples from patients with clinical stage T4 cancer. Increased concentrations of SFRP1 and SFRP5 were present in stage III NSCLC samples, while the tumour samples with high pleural invasion (PL2) had an increased level of SFRP2. The results from this study suggest that the tumour suppressor or oncogenic roles of SFRPs could be connected with the NSCLC subtype. The levels of SFRPs varied according to the clinicopathological parameters of NSCLC.

The synergy of serum SFRP5 levels and the TyG index in predicting coronary artery disease and prognosing major adverse cardiovascular events

BACKGROUND AND AIMS

Secreted frizzled-related protein 5 (SFRP5) is a member of the SFRP family that is known for its potent anti-inflammatory properties. Nevertheless, little is known regarding the relevance of SFRP5 in coronary artery disease (CAD). The current study examined the correlation between serum levels of SFRP5 and the triglyceride-glucose (TyG) index in patients who underwent coronary angiography (CAG) as a component of cardiovascular assessment and for the purpose of prognosis evaluation.

METHODS

A total of 310 hospitalized patients were enrolled in this study between May 2021 and March 2022 and were divided into three groups based on their CAG results and SYNTAX (synergy between PCI with TAXUS drug-eluting stent and cardiac surgery) scores: the control group, mild lesion group, and moderate-severe lesion group. Univariate and multivariate analyses were employed to investigate the relationships between changes in patients and clinical variables. To investigate the impact of the TyG index and serum SFRP5 levels on the occurrence of major adverse cardiovascular events (MACEs), Kaplan‒Meier curves were plotted. Serum SFRP5 levels were measured utilizing an enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

The serum SFRP5 levels significantly decreased with the increasing severity and complexity of CAD, while the TyG index significantly increased (P < 0.001). Moreover, a significant negative correlation was observed between the serum SFRP5 levels and the TyG index (r = -0.312, P < 0.001). SFRP5 exerts a protective role in different groups of patients. The area under the receiver operating characteristic (ROC) curve indicated that an SFRP5 concentration > 115.58 pg/mL was the best predictive value for CAD (OR:0.87, P < 0.001). MACEs were significantly associated with serum SFRP5 levels and the TyG index, as indicated by both univariate and multivariate Cox regression analyses (P < 0.001). Furthermore, Kaplan‒Meier analysis indicated that as the TyG index decreased and SFRP5 levels increased, the occurrence of MACEs decreased (P < 0.001). Patients with a concentration of SFRP5 > 115.58 pg/mL and a TyG index < 8.49 exhibited a better prognosis for avoiding MACEs (P < 0.001).

CONCLUSION

These results suggest that the collaboration between serum SFRP5 levels and the TyG index holds promise in predicting CAD and its prognosis.

Secreted frizzled-related protein 5: A promising therapeutic target for metabolic diseases via regulation of Wnt signaling

Metabolic diseases pose a significant global health challenge, characterized by an imbalance in metabolism and resulting in various complications. Secreted frizzled-related protein 5 (SFRP5), an adipokine known for its anti-inflammatory properties, has gained attention as a promising therapeutic target for metabolic diseases. SFRP5 acts as a key regulator in the Wnt signaling pathway, exerting its influence on critical cellular functions including proliferation, differentiation, and migration. Its significance extends to the realm of adipose tissue biology, where it plays a central role in regulating inflammation, insulin resistance, adipogenesis, lipid metabolism, glucose homeostasis, and energy balance. By inhibiting Wnt signaling, SFRP5 facilitates adipocyte growth, promotes lipid accumulation, and contributes to a decrease in oxidative metabolism. Lifestyle interventions and pharmacological treatments have shown promise in increasing SFRP5 levels and protecting against metabolic abnormalities. SFRP5 is a pivotal player in metabolic diseases and presents itself as a promising therapeutic target. An overview of SFRP5 and its involvement in metabolic disorders and metabolism is provided in this comprehensive review. By elucidating these aspects, valuable insights can be gained to foster the development of effective strategies in combating metabolic diseases.

Cumulative effects of exercise training and consumption of propolis on managing diabetic dyslipidemia in adult women: a single-blind, randomized, controlled trial with pre-post-intervention assessments

Dyslipidemia is an imbalance of various lipids, and propolis, as a natural resinous viscos mixture made by Apis mellifera L. could improve in this condition. In this single-blind, randomized trial, 60 women with type 2 diabetes and dyslipidemia were divided into four groups: (1) the patients who did not apply the combined training and 500 mg propolis capsules supplement (Control group); (2) subjects performed combined training, including aerobic and resistance training (EXR); (3) subjects received the 500 mg propolis supplement capsules (SUPP); (4) Subjects performed combined training along with receiving the 500 mg propolis supplement capsules (EXR + SUPP). We evaluated the concentration of CTRP12, SFRP5, interleukin-6 (IL6), superoxide dismutase (SOD), malondialdehyde (MDA), adiponectin, and total antioxidant capacity (TAC) before and after the intervention. MDA, TAC, IL6, CTRP12, SFRP5 IL6, adiponectin, and lipid profile levels ameliorated in the EXR + SUPP group. We found that 8 weeks of treatment by combined exercise training and propolis supplement decreased inflammation activity and increased antioxidant defense in women with diabetic dyslipidemia.Trial registration This study was registered in the Iranian Registry of Clinical Trials; IRCT code: IRCT20211229053561N1.

TFAP2C inhibits cell autophagy to alleviate myocardial ischemia/reperfusion injury by regulating miR-23a-5p/SFRP5/Wnt5a axis

Myocardial ischemia/reperfusion (MI/R) injury contributes to severe injury for cardiomyocytes. In this study, we aimed to explore the underlying mechanism of TFAP2C on cell autophagy in MI/R injury. MTT assay measured cell viability. The cells injury was evaluated by commercial kits. IF detected the level of LC3B. Dual luciferase reporter gene assay, ChIP or RIP assay were performed to verify the interactions between crucial molecules. We found that TFAP2C and SFRP5 expression were decreased while miR-23a-5p and Wnt5a increased in AC16 cells in response to H/R condition. H/R induction led to cell injury and induced autophagy, which were reversed by TFAP2C overexpression or 3-MA treatment (an autophagy inhibitor). Mechanistically, TFAP2C suppressed miR-23a expression through binding to miR-23a promoter, and SFRP5 was a target gene of miR-23a-5p. Moreover, miR-23a-5p overexpression or rapamycin reversed the protective impacts of TFAP2C overexpression on cells injury and autophagy upon H/R condition. In conclusion, TFAP2C inhibited autophagy to improve H/R-induced cells injury by mediating miR-23a-5p/SFRP5/Wnt5a axis.

Pinostrobin induces acute leukemia cell apoptosis via the regulation of miR-410-5p and SFRP5

AIMS

This study attempted to explore the mechanisms involved in pinostrobin (PN)-mediated acute leukemia cell apoptosis regulated by miR-410-5p.

MATERIAL AND METHODS

NB4 and MOLT-4 cells were cultured and treated with PN at the IC50 concentration. Apoptosis was examined by Annexin V-FITC/PI staining. RT-qPCR was used to measure the expression of caspase-3, BAK, BCL-W, and MCL-1. The target protein of PN was identified using LC-MS/MS followed by bioinformatic analysis. TargetScan, DIANA, and miRDB were used for the prediction of miRNAs involved in the PN-induced apoptosis mechanism. miRNA mimic transfection, RT-qPCR, and western blot analysis were performed to evaluate the regulatory effect of miRNA on its target and the involvement of miRNA in apoptosis induction by PN. In addition, the synergistic effect of PN and daunorubicin (DNR) were investigated by using the MTT assay.

KEY FINDINGS

The results showed that PN reduced cell viability and induced apoptosis in both leukemia cell lines. From the LC-MS/MS and bioinformatics analysis, SFRP5 and miR-410-5p were selected as a potential PN target protein and miRNA, respectively. After miRNA mimic transfection, miR-410-5p, which is an onco-miRNA, was decreased and led to increased apoptosis in both cell lines, indicating that this miRNA is involved in PN-mediated apoptosis mechanisms. Moreover, PN demonstrated a synergistic effect with DNR, suggesting that PN may be used in combination with conventional chemotherapy drugs.

SIGNIFICANCE

PN regulates the expression of miR-410-5p and SFRP5 to promote apoptosis in acute leukemia cells. It could be developed as an alternative treatment for leukemia in the future.

Frizzled receptors and SFRP5 in lipid metabolism: Current findings and potential applications

Lipid metabolism plays a very important role as the central metabolic process of the body. Lipid metabolism interruptions may cause many chronic diseases, for example, non-alcoholic fatty liver disease (NAFLD), diabetes, and obesity. Secreted Frizzled Related Protein 5 (SFRP5) and Frizzled receptors (FZD) are two newly discovered adipokines that are involved in lipid metabolism as well as lipogenesis. Both of these adipokines affect lipid metabolism and adipogenesis through three WNT signaling pathways (WNTSP): WNT/β-catenin, WNT/Ca²⁺, and WNT/JNK. FZD consists of 10 species, which have a cysteine-rich domain (CRD) to bind to the WNT protein for signal transduction. Depending on the type of ligand or co-receptor, they can stimulate or inhibit adipogenesis. In lipid metabolism, they play a role in recognizing fatty acids. In obesity, gene expression of the WNT/FZD receptors is significantly increased. In contrast, SFPR5 serves as an antagonist that can compete with FZD for inhibition of WNTSP. It is believed to have anti-inflammatory potential in obesity and diseases related to abnormal lipid metabolism. In these cases, the expression of SFRP5 is found to be very low leading to the promoted production of proinflammatory cytokines (PICS). Some methods that include using recombinant SFRP5 to improve non-alcoholic steatohepatitis (NASH), using secreted Ly-6/uPAR-related protein 1 (Slurp1) to regulate fat accumulation in the liver through SFRP5, and dietary and lifestyle interventions to improve overweight/obesity have been studied. However, understandings of the molecular mechanisms of these two adipokines and their interactions are very limited. Therefore, more in-depth studies are needed in the future.

Secreted frizzled-related protein 5 promotes angiogenesis of human umbilical vein endothelial cells and alleviates myocardial injury in diabetic mice with myocardial infarction by inhibiting Wnt5a/JNK signaling

The purpose of this study is to investigate whether secreted frizzled-related protein 5 (SFRP5) affects the proliferation, migration and angiogenesis of human umbilical vein endothelial cells (HUVECs) induced by high glucose (HG). HUVECs were treated with different concentrations of glucose. MTT, wound healing, angiogenesis, and ELISA assays were used to detect cell cytotoxicity, migration, tube formation, and VEGF165 and VEGF165b levels, respectively. The mice model of type 2 diabetes mellitus (T2DM) complicated with myocardial infarction (MI) was established. SFRP5 was injected intrabitoneally for 2 weeks. cardiac output (CO), left ventricular ejection fraction (LVEF) and left ventricular shortening fraction (LVSF) were detected by echocardiography. Western blot was used to detect the protein levels of SFRP5, Wnt5a, JNK1/2/3, p-JNK1/2/3, TGF-β1, Caspase3, Bax, and Bcl-2. The expression of SFRP5 was declined in HG-induced HUVECs and T2DM-MI. Intervention of SFRP5 promoted the migration of HUVECs and angiogenesis, as evidenced by a lower expression of Bax and caspase3, but a higher expression of Bcl-2. Meanwhile, SFRP5 inhibition repress Wnt5a and p-JNK expression. Howerver, The JNK inhibitor (SP600125) enhanced the down-regulation of Wnt5a/JNK pathway proteins by SFRP5. SFRP5 intervention increased the levels of CO, LVSF, and LVEF in T2DM-MI mice. SFRP5 inhibited myocardial pathological injury and fibrosis in T2DM-MI mice and SFRP5 could down-regulate Wnt5a and p-JNK1/2/3 activation. SFRP5 promotes the proliferation, migration and angiogenesis of HUVECs induced by HG, and inhibits cardiac dysfunction, pathological damage, fibrosis, and myocardial angiogenesis in diabetic myocardial ischemia mice, which is achieved by inhibiting Wnt5a/JNK signaling.

The Role of Anti-Inflammatory Adipokines in Cardiometabolic Disorders: Moving beyond Adiponectin

The global burden of obesity has multiplied owing to its rapidly growing prevalence and obesity-related morbidity and mortality. In addition to the classic role of depositing extra energy, adipose tissue actively interferes with the metabolic balance by means of secreting bioactive compounds called adipokines. While most adipokines give rise to inflammatory conditions, the others with anti-inflammatory properties have been the novel focus of attention for the amelioration of cardiometabolic complications. This review compiles the current evidence on the roles of anti-inflammatory adipokines, namely, adiponectin, vaspin, the C1q/TNF-related protein (CTRP) family, secreted frizzled-related protein 5 (SFRP5), and omentin-1 on cardiometabolic health. Further investigations on the mechanism of action and prospective human trials may pave the way to their clinical application as innovative biomarkers and therapeutic targets for cardiovascular and metabolic disorders.

Serum secreted frizzled-related protein 5 in relation to insulin sensitivity and its regulation by insulin and free fatty acids

PURPOSE

Secreted frizzled-related protein 5 (SFRP5) is an adipokine, which acts as an inhibitor of noncanonical WNT signaling pathway. It has been suggested to exert anti-inflammatory and insulin-sensitizing effects, however, contradictory data has also been reported. The aim of this study was to assess serum SFRP5 concentration in a young healthy population in relation to insulin sensitivity and its regulation by hyperinsulinemia and/or serum free fatty acids (FFA) elevation.

METHODS

We examined 150 healthy subjects (83 normal-weight and 67 overweight/obese). Insulin sensitivity (M) was measured with hyperinsulinemic-euglycemic clamp. In 20 male subjects, clamp was prolonged to 6 h and after 1 week another clamp with the concurrent Intralipid/heparin infusion was performed. Independent group of 10 male subjects received infusions of Intralipid/heparin or saline in 1-week interval.

RESULTS

Baseline SFRP5 was lower in the overweight/obese group (p = 0.01) and was positively associated with M (r = 0.23, p = 0.006) and serum adiponectin (r = 0.55, p < 0.001) and negatively with BMI (r = -0.18, p = 0.03). In multiple regression analysis, adiponectin was independently associated with SFRP5. Insulin infusion resulted in a decrease in serum SFRP5, both at 120' (p = 0.02) and 360' (p = 0.031). This effect was not observed during the clamp with Intralipid/heparin as well as during Intralipid/heparin alone or saline infusions.

CONCLUSIONS

The relation between SFRP5 and insulin sensitivity is mainly dependent on adiponectin. FFA abolish a decrease in circulating SFRP5 caused by insulin, but Intralipid/heparin infusion alone does not regulate SFRP5 concentration. Insulin seems to be more important factor in the regulation of circulating SFRP5 levels than FFA.

Elevated Serum SFRP5 Levels During Preeclampsia and Its Potential Association with Trophoblast Dysfunction via Wnt/β-Catenin Suppression

Preeclampsia (PE) is a life-threatening pregnancy complication associated with diminished trophoblast migration and invasion. Wnt signalling is one of the most important regulators of placentation. Secreted frizzled-related protein 5 (SFRP5) is an anti-inflammatory adipokine that may inhibit Wnt signalling. In this study, we aimed to investigate the relationship between SFRP5 and PE and its effect on trophoblast function, as well as the underlying signalling pathways. SFRP5 levels in the serum and placental tissues were detected using enzyme-linked immunosorbent assay and immunohistochemistry, respectively. To evaluate the effect of SFRP5 on Wnt signalling, the human trophoblast cell line HTR8/SVneo was treated with recombinant human SFRP5 and Dickkopf-related protein 1 (Dkk-1, canonical Wnt inhibitor) proteins and lithium chloride (LiCl, canonical Wnt agonist). The migration and invasion ability of HTR8/SVneo cells was evaluated using wound-healing and Matrigel Transwell assays. The activities of multiple matrix metalloproteinases (MMP)-2/9 were detected using gelatin zymography. Expression of glycogen synthase kinase-3 beta (GSK3β) and β-catenin proteins was investigated using western blotting. The serum SFRP5 levels were elevated in patients with PE, but SFRP5 expression was not detected in the placental tissues. Furthermore, SFRP5 inhibited the migration and invasion of HTR8/SVneo cells in vitro, increased GSK3β, and decreased β-catenin expression and MMP-2/9 activity in HTR8/SVneo cells. In conclusion, this study suggests that SFRP5 inhibits trophoblast migration and invasion potentially via the inhibition of Wnt/β-catenin signalling, which might be involved in the development of PE. However, the primary cause of the increased SFRP5 levels needs to be investigated.

The Emerging Role of Sfrp5 and Wnt5a in the Pathogenesis of Obesity: Implications for a Healthy Diet and Lifestyle

In recent decades, the prevalence of obesity has risen dramatically worldwide among all age groups. Obesity is characterized by excess fat accumulation and chronic low-grade inflammation. The adipose tissue functions as a metabolically active endocrine organ secreting adipokines. A novel duo of adipokines, the anti-inflammatory secreted frizzled-related protein 5 (Sfrp5) and the proinflammatory wingless type mouse mammary tumor virus (MMTV) integration site family member 5A (Wnt5a), signal via the non-canonical Wnt pathway. Recent evidence suggests that Sfpr5 and Wnt5a play a key role in the pathogenesis of obesity and its metabolic complications. This review summarizes the current knowledge on the novel regulatory system of anti-inflammatory Sfrp5 and pro-inflammatory Wnt5a, and their relation to obesity and obesity-related complications. Future studies are required to investigate the potential role of Sfrp5 and Wnt5a as biomarkers for monitoring the response to lifestyle interventions and for predicting the development of cardiometabolic risk factors. These adipokines may also serve as novel therapeutic targets for obesity-related disorders.

Deregulation of Secreted Frizzled-Related Protein 5 in Nonalcoholic Fatty Liver Disease Associated with Obesity

Secreted frizzled-related protein 5 (SFRP5), an antagonist of the noncanonical WNT pathway, has a controversial role in liver disease. The aim of this study was to analyze the role of SFRP5 and the noncanonical WNT pathway in nonalcoholic fatty liver disease (NAFLD). Plasma SFRP5 levels were determined by ELISA in women with normal weight (NW; n = 20) and morbid obesity (MO; n = 69). Women with MO were subclassified according to hepatic histology into normal liver (NL; n = 28), NAFLD (n = 41) (simple steatosis (SS; n = 24), and nonalcoholic steatohepatitis (NASH; n = 17)). We used RT-qPCR to evaluate the hepatic mRNA expression of SFRP5, WNT5A, and JNK in women with MO. SFRP5 levels were lower in NW than in MO patients who underwent a very low-calorie diet before surgery. Hepatic SFRP5 mRNA expression was higher in SS than in NL or NASH; additionally, patients with hepatic inflammation or ballooning presented lower SFRP5 abundance. WNT5A and JNK expression was enhanced in NAFLD compared with NL. In conclusion, circulating SFRP5 levels depend on the diet, and hepatic SFRP5 seems to have a protective role in the first steps of NAFLD; however, SFRP5 could be deregulated in an advanced stage while WNT5A and JNK are activated, promoting liver damage.

The PPAR-γ/SFRP5/Wnt/β-catenin signal axis regulates the dexamethasone-induced osteoporosis

BACKGROUND

The inhibition of glucocorticoid (GC) on osteoblastic differentiation of bone marrow stromal stem cells (BMSC) is an important pathway for GC to reduce bone formation. Recent studies implicated an important role of peroxisome proliferator-activated receptor-gamma (PPAR-γ) in GC-mediated cell proliferation and differentiation. Thus, our purpose is to investigate the role of PPAR-γ in regulating rat BMSC (rBMSC) osteoblastic differentiation.

METHODS

The rBMSC treated with dexamethasone (Dex) was used to construct an in vitro cell model of GC-induced osteoporosis. The expressions of PPAR-γ, RUNX2, ALP, OPN and SFRP5 in cells were detected by RT-qPCR and western blot assays. Osteogenic differentiation of rBMSC was measured by Alizarin Red S (ARS) staining analysis. Lentivirus-delivered shRNA was used to knock down PPAR-γ or SFRP5, and lentivirus-delivered constructs were used to overexpress SFRP5 in rBMSC to verify the effect of PPAR-γ or SFRP5 on cell osteogenic differentiation.

RESULTS

Dex significantly reduced rBMSC osteoblastic differentiation. The expression of PPAR-γ was enhanced in Dex treated rBMSC. PPAR-γ down-regulation improved Dex inhibition of rBMSC osteogenic differentiation. Moreover, PPAR-γ knockdown promoted protein levels of RUNX2, ALP, OPN and Dex-decreased rBMSC osteogenic differentiation. The expression of SFRP5 was reduced while Wnt and β-catenin were increased in PPAR-γ knockdown and Dex treated rBMSC. Moreover, the up-regulation of SFRP5 reversed the osteogenic differentiation of rBMSC induced by PPAR-γ knockdown.

CONCLUSION

These data indicated that in GC-induced osteoporosis, PPAR-γ/SFRP5 affects osteogenic differentiation by regulating the Wnt/β-catenin signaling pathway.

SFRP5 mediates downregulation of the wnt5a/caveolin-1/JNK signaling pathway

This study investigated the effects of Wnt5a/caveolin/JNK signaling pathway and SFRP5 protein on ox-LDL-induced apoptosis of HUVEC cells. The difference of serological indexes between healthy average weight and obese children and the expression of Wnt 5a and SFRP5 was detected by clinical examination, and the correlation between serum SFRP5, Wnt 5a and the vascular endothelial injury was detected. HUVEC cells were induced by ox-LDL to construct an endothelial injury model, siRNA-transfected cells were used to construct downregulated SFRP5 and Wnt 5a expression groups, and recombination methods were used to construct upregulated Wnt5a and SFRP5 expression groups. The expression of Wnt 5a, caveolin-1, JNK and apoptosis-related proteins under different treatments were detected by the Western blot method, and apoptosis was detected by flow cytometry. Serological results showed that the level of Sfrp5 in obese children was significantly lower than that in healthy children, and the level of Wnt5a was significantly higher than that in healthy children. Moreover, Ln Sfrp5 was significantly negatively correlated with Ang-2 in blood circulation, ICAM-1 and E-selectin selectin, but not with VCAM-1. When Wnt5a was upregulated, the expression of caveolin-1 and JNK increased significantly, Bcl-2 decreased significantly, and the apoptotic rate increased significantly. Nevertheless, when Sfrp5 expression was upregulated, the result was the opposite. SFRP5 and Wnt5a are involved in the vascular endothelial injury. Wnt5a can promote apoptosis of HUVEC cells through Wnt5a/JNK/Caveolin-1 pathway, while SFRP5 can inhibit apoptosis by interfering with this pathway.

SFRP5 inhibits melanin synthesis of melanocytes in vitiligo by suppressing the Wnt/β-catenin signaling

Secreted frizzled-related protein 5 (SFRP5) plays a pivotal role in regulating the development of many tissues and organs, however, as an inhibitor of Wnt signaling, the role of SFRP5 in vitiligo remains unknown. Hence, we speculated that SFRP5 might be associated with melanogenesis in melanocytes by regulating Wnt signaling in vitiligo. In this study, we found that SFRP5 was overexpressed in the skin lesions of patients with vitiligo. Compared with that in normal epidermal melanocytes (PIG1), the expression of SFRP5 was increased in vitiligo melanocytes (PIG3V). To investigate the effect of SFRP5 on melanin synthesis, PIG1 cells were infected with recombinant SFRP5 adenovirus (AdSFRP5), and PIG3V cells were infected with recombinant siSFRP5 adenovirus (AdsiSFRP5). The results showed that SFRP5 overexpression inhibited melanin synthesis in PIG1 cells through downregulation of microphthalmia-associated transcription factor (MITF) and its target proteins via suppression of the Wnt/β-catenin signaling pathway. Accordingly, SFRP5 silencing increased melanin synthesis and activated the Wnt signaling pathway in PIG3V cells. Moreover, SFRP5 overexpression also downregulated the transcriptional activity of T cell factor/lymphoid enhancer factor (TCF/LEF) in PIG1 cells. Furthermore, this inhibitory effect of SFRP5 on melanin synthesis was reversed by treatment with the β-catenin agonist, SKL2001. The inhibitory action of SFRP5 in pigmentation was further confirmed in vivo using a nude mouse model. Hence, our results indicate that SFRP5 can inhibit melanogenesis in melanocytes. Additionally, our findings showed that SFRP5 plays a vital role in the development of vitiligo, and thus may serve as a potential therapeutic target for vitiligo.

Research update on the association between SFRP5, an anti-inflammatory adipokine, with obesity, type 2 diabetes mellitus and coronary heart disease

Secreted frizzled-related protein 5 (SFRP5), an anti-inflammatory adipokine secreted by adipocytes, has been demonstrated to exert its anti-inflammatory effect via antagonizing the non-canonical wingless-type family member 5A (WNT5A) signalling pathways. The WNT5A protein, as a potent pro-inflammatory signalling molecule, is strongly involved in a variety of inflammatory disorders such as obesity, type 2 diabetes mellitus (T2DM) and atherosclerosis. In this review, we systematically outlined the current understanding on the roles of SFRP5 in the pathogenesis of three inflammatory diseases including obesity, T2DM and coronary heart disease (CHD). Our review might stimulate future research using SFRP5 as a promising novel therapeutic target for the treatment of obesity, T2DM and CHD.

Association of Adipocytokines With Carotid Intima Media Thickness and Arterial Stiffness in Obstructive Sleep Apnea Patients

Objective: Obstructive sleep apnea (OSA) results in increased carotid intima-media thickness (IMT) and arterial stiffness; however, the association between adipocytokines and IMT/arterial stiffness in OSA patients is unclear. Methods: We enrolled 95 normal weight and overweight, not obese, participants from May 2018 to December 2018 in this study. All subjects underwent a carotid artery ultrasound examination and polysomnography. Blood samples were used to determine serum chemerin, adiponectin, SFRP5, and apelin levels. Correlations between two quantitative variables were assessed using the Pearson or Spearman coefficient. Stepwise models of multiple linear regression analysis were performed to assess the independent relationships. Result: IMT in OSA patients was significantly higher than in the non-snorers. There were significant differences in the arterial stiffness parameters such as distensibility coefficient (DC), compliance coefficient (CC), and pulse wave velocity (PWV). SFRP5 level was lower in OSA patients than in non-snorers. Adiponectin correlated with CC, DC, and PWV among OSA patients; however, the relationship disappeared after a multivariable adjustment. Age was independently associated with all quantitative IMT and stiffness indices. AHI and minimum oxygen saturation (Mini SaO₂) were independently related to arterial stiffness. Conclusion: The quantitative IMT and carotid arterial elasticity were significantly worse among OSA patients. Age was the main independent factor correlated with quantitative IMT and arterial stiffness, and AHI and mini SaO₂ were associated factors. There were no relationships between aforementioned adipocytokines and quantitative IMT/carotid arterial stiffness.

Adipocyte-derived SFRP5 inhibits breast cancer cells migration and invasion through Wnt and epithelial-mesenchymal transition signaling pathways

Objective

Obesity is closely associated with metastasis in breast cancer patients. Secreted frizzled-related protein 5 (SFRP5), one of the novel adipokines with anti-inflammatory properties, is associated with obesity. This study aims to study the role of SFRP5 in the crosstalk between obesity and breast cancer metastasis and identify the underlying mechanism.

Methods

3T3-L1 pre-adipocytes were differentiated to mature adipocytes and a hypertrophic adipocyte model was induced with palmitic acid (PA). Cell motility was measured in MDA-MB-231 and MCF-7 breast cancer cells co-cultured with adipocytes conditioned medium (CM) with or without SFRP5 protein. Wnt and epithelial-mesenchymal transition (EMT) signal pathways were investigated by western blot. Circulating SFRP5 level in 218 breast cancer patients and the association with clinicopathologic characteristics of breast cancer were further determined. Online databases ENCORI and PREDICT Plus were used to exam the link between SFRP5 and prognosis.

Results

Reduced SFRP5 level was detected in the hypertrophic adipocyte model. Recombinant SFRP5 protein inhibited MDA-MB-231 and MCF-7 cells invasion and migration induced by PA-treated adipocyte CM, and SFRP5 inhibition by specific antibody reversed the effect of SFRP5. Furthermore, SFRP5 significantly inhibited Wnt and downstream EMT in breast cancer cells. Low circulating SFRP5 level correlated with body mass index (BMI), lymph node (LN) metastasis, TNM stage and high Ki67 expression in breast cancer patients. Increased SFRP5 level was associated with favorable predicted survival. Kaplan-Meier curves showed high SFRP5 level in tumor tissue was associated with better outcome of breast cancer patients.

Conclusions

Our findings demonstrated SFRP5 is a vital adipokine that mediates the crosslink between obesity and the metastatic potential of breast cancer. Promotion of SFRP5 expression in the adipose microenvironment may represent a novel approach for preventing breast cancer metastasis.

Raloxifene inhibits adipose tissue inflammation and adipogenesis through Wnt regulation in ovariectomized rats and 3 T3-L1 cells

BACKGROUND

Loss of ovarian function, as in menopause or after ovariectomy (OVX), is closely associated with obesity and white adipose tissue (WAT) inflammation. Estrogen replacement protects against postmenopausal obesity but increases the risks of carcinogenesis. In the present study, we investigated the effects of long-term treatment of raloxifene (RAL), a selective estrogen receptor modulator, on the features of estrogen deficiency-induced obesity and explored the involvement of canonical and non-canonical Wnt regulation in vivo and in vitro.

METHODS

Adult female rats received bilateral OVX and divided into 5 groups: (1) Sham, (2) OVX, (3) OVX + E₂: OVX rats were administered with E₂ (50 μg/kg, s.c., 3 times/week), (4) OVX + RAL: OVX rats were treated with RAL (gavage, 1 mg/kg/day) suspended in 0.8% carboxymethylcellulose (CMC), (5) OVX + CMC: 0.8% CMC as vehicle control. All treatments were given for 8 weeks beginning at 1 week after OVX. In 3 T3-L1 cells, the effects of RAL on adipogenesis and lipopolysaccharide (LPS)-induced inflammation were evaluated.

RESULTS

Treatment with RAL significantly decreased body weight, visceral fat pad mass, adipocyte size and plasma levels of glucose but increased plasma adiponectin. RAL reduced the elevation of HIF-1α, VEGF-A and proinflammatory cytokines (MCP-1 and TNF-α) expression by inhibition of NF-κB p65 and JNK cascades in retroperitoneal WAT. This anti-inflammatory capacity of RAL may result from upregulation of secreted frizzle-related protein 5 (SFRP5), an adipokine that repressed Wnt5a signaling. Furthermore, RAL inhibited adipogenic factors such as PPAR-γ, C/EBP-α, and FABP4, and preserved canonical Wnt10b/β-catenin protein expression. In 3 T3-L1 adipocytes, RAL (20 μM) diminished lipid accumulation and inhibited adipogenic factors accompanied with the induction of β-catenin, which were effectively reversed by the β-catenin inhibitor IWR-1-endo. In addition, RAL reduced LPS-induced NF-κB p65 and p-IκB expression as well as TNF-α secretion. Suppression of SFRP5 by small interfering RNA significantly abrogated the anti-inflammatory effects of RAL.

CONCLUSIONS

Distinct activation of canonical β-catenin on inhibition of adipogenesis and non-canonical SFRP5 on suppression of WAT inflammation may contribute to the beneficial effects of RAL. Therefore, this study provides a rationale for the therapeutic potential of RAL for postmenopausal obesity.

Vitamin D3 supplementation improves serum SFRP5 and Wnt5a levels in patients with type 2 diabetes: A randomized, double-blind, placebo-controlled trial

Objective: To explore the effect of vitamin D3 on novel serum adipokines, secreted frizzled-related protein 5 (SFRP5) and Wingless-Type MMTV Integration Site Family Member 5a (Wnt5a) levels in Type 2 Diabetes Mellitus (T2DM) patients. Methods: Forty patients (16 women and 24 men) with type 2 diabetes participated in this double-blind, randomized, placebo-controlled clinical trial study. Participants were randomly assigned to receive 4000 IU vitamin D₃ (n = 20) or placebo (n = 20) daily for 2 months. Anthropometric indices, fasting blood glucose (FBS), hemoglobin A1c (HbA1c), insulin, serum tumor necrosis factor (TNF)-α, Wnt5a, SFRP5, physical activity, lipid profile, dietary intake, and serum calcidiol were assessed at the baseline and after 8 weeks. Results: In the group receiving Vitamin D, a significant increase in Calicidiol (15.03 ± 10.44 vs. 27.33 ± 11.2 ng/dl; P = < 0.001), SFRP5 (3.6 ± 0.46 vs. 3.98 ± 0.59 ng/ml; P = 0.01), and Wnt5a (0.33 ± 0.129 vs. 0.29 ± 0.047; P = 0.03) was observed. After two months supplementation, there were significant between-group differences in Calicidiol (27.33 ± 11.2 vs. 17.9 ± 12.95 ng/dl; P = 0.01), TNF-α (89.22 ± 34.28 vs. 164.93 ± 120.45 ng/ml; P = 0.006), Wnt5a (0.29 ± 0.047 vs. 0.33 ± 0.09; P = 0.04), and HbA1c (6.6 ± 0.96 % vs. 7.64 ± 1.15 %; p = 0.002). Moreover, the net changes (end - baseline) of Calicidiol (P = < 0.001), SFRP5 (P = 0.04), Wnt5a (P = 0.005), TNF-α (P = 0.01), insulin (P = 0.03), and QUICKI (P = 0.01) was significant between the groups. There were no significant effects on FBS and homeostasis model of assessment-estimated insulin resistance (HOMA-IR). Conclusion: 8 weeks of vitamin D3 supplementation for patients with type 2 diabetes may increase serum anti-inflammatory adipokine SFRP5 but decrease serum pro-inflammatory Wnt5a and TNF-α.

Cinnamon extract combined with high-intensity endurance training alleviates metabolic syndrome via non-canonical WNT signaling

OBJECTIVES

The incidence of metabolic syndrome (MetS) in menopausal women is one of the main health care concerns. MetS clusters are related to an imbalance in pro- and anti-inflammatory adipokines such as secreted frizzled-related protein 5 (SFRP5) and wingless-type mammary tumor virus integration site family, member 5A (WNT5A). WNT5A induces an inflammatory state to induce insulin resistance and further pathologic consequences. Recent strategies to prevent progression of MetS to diabetes have focused on conservative treatments such as exercise and herbal medicine. The aim of this study was to investigate the mechanistic effects of cotreatment with cinnamon extract and 12-wk high-intensity endurance training on MetS components considering the non-canonical WNT5A signaling.

METHOD

Thirty-two female ovariectomized Wistar rats were divided into the following four groups (n = 8/group): exercise (Ova+Exe), cinnamon extract (Ova+Cin), exercise with cinnamon extract (Ova+Exe+Cin) and saline (Ova+Sal). One group of rats undergoing surgery without removal of the ovaries was considered as a sham. After 3 mo of experimental intervention, waist circumference, serum concentrations of glucose, insulin, lipid profile, tumor necrosis factor-α, WNT5A, and SFRP5 were measured.

RESULTS

Data showed a significant reduction in serum glucose, low-density lipoprotein, homeostasis model assessment estimate of insulin resistance, and tumor necrosis factor-α, but an increase in SFRP5 level in Ova+Exe, Ova+Cin and Ova +Exe+Cin groups compared with Ova+Sal group (P < 0.05). Serum WNT5A significantly was reduced only in Ova+Exe+Cin group (P = 0.02).

CONCLUSION

The present study indicated that high-endurance training combined with aqueous cinnamon extract supplementation for 12 wk more efficiently alleviated insulin resistance and metabolic dysfunctions via reduction in noncanonical WNT signaling in ovariectomized rats.

SFRP5 inhibits the migration and invasion of melanoma cells through Wnt signaling pathway

Background

Secreted frizzled-related protein 5 (SFRP5) plays a key role in the development and progression of multiple tumors. However, the role and underlying mechanisms of SFRP5 in melanoma cells remain unknown.

Materials and methods

We used immunohistochemistry and Western blot analysis to detect the expression of SFRP5 in melanoma tissues and melanoma cells, respectively. Furthermore, both in vitro and in vivo assays were used to determine the effect of SFRP5 on malignant behavior in melanoma cells.

Results

We found that SFRP5 was markedly downregulated in melanoma tissues and cell lines. The SFRP5 overexpression exhibited no effect on the proliferation and apoptosis of melanoma cells but markedly suppressed the migration and invasion of melanoma cells in vitro. Regarding mechanisms, the SFRP5 overexpression inhibited the migration and invasion of melanoma cells by suppressing the epithelial–mesenchymal transition process and decreasing the matrix metalloproteinase-2/9 expression through the Wnt signaling pathway. Finally, in a xenograft animal model, we illustrated that the SFRP5 overexpression suppressed the tumor growth by decreasing angiogenesis and declined lung metastasis.

Conclusion

This study suggests that SFRP5 expression could be potentially useful in the invasion and metastasis of melanoma and serve as a putative promising target for human melanoma therapy.

CDH1, DLEC1 and SFRP5 methylation panel as a prognostic marker for advanced epithelial ovarian cancer

AIM

To investigate the CDH1, DLEC1 and SFRP5 gene methylation panel for advanced epithelial ovarian carcinoma (EOC).

MATERIALS & METHODS

One hundred and seventy-seven advanced EOC specimens were evaluated by methylation-specific PCR. We also used The Cancer Genome Atlas dataset to evaluate the panel.

RESULTS

The presence of two or more methylated genes was significant in recurrence (hazard ratio [HR]: 1.91 [1.33-2.76]; p = 0.002) and death (HR: 1.96 [1.26-3.06]; p = 0.006) in our cohort. In The Cancer Genome Atlas dataset, the presence of two or three methylated genes was significant in death (HR: 1.59 [1.15-2.18]; p = 0.0047) and close to the significance level in recurrence (HR: 1.37 [0.99-1.88]; p = 0.058).

CONCLUSION

The CDH1, DLEC1 and SFRP5 methylation panel is a potential prognostic biomarker for advanced EOC.

Epigenetic silencing of SFRP5 promotes the metastasis and invasion of chondrosarcoma by expression inhibition and Wnt signaling pathway activation

BACKGROUD/AIMS

Abnormal activation of the Wnt/β-catenin signaling, which may be antagonized by the members of secreted frizzled-related proteins family (SFRPs), is implicated in tumor occurrence and development. However, the function of SFRP5 relating to Wnt/β-catenin pathway in chondrosarcoma is not clear yet. This study was undertaken to investigate the potential role of SFRP5 promoter methylation in chondrosarcoma metastasis and invasion through activating canonical Wnt signaling pathway.

METHODS AND RESULTS

The results demonstrated that SFRP5 promoter was hypermethylated and SFRP5 expression was significantly reduced in chondrosarcoma cell lines at the mRNA and protein levels. The canonical Wnt/β-catenin signaling was observably activated with β-catenin stabilization by dephosphorylation and translocation into the nuclear. 5-Aza-2'-deoxycytidine (5-Aza-dC), the DNA methyltransferase inhibitor, significantly inhibited the proliferation of chondrosarcoma cells by cell cycle arrest through repressing the methylation of SFRP5 and promoting its expression. Both 5-Aza-dC treatment and SFRP5 overexpression could significantly inhibited the metastasis and invasion of chondrosarcoma cells by inactivating Wnt/β-catenin signaling pathway and promoting chondrosarcoma cells mesenchymal-epithelial transition (MET). 5-Aza-dC also inhibited the xenograft growth and lung metastasis of chondrosarcoma cells in vivo via suppressing SFRP5 promotor methylation, inactivating Wnt/β-catenin pathway and inducing epithelial markers expression.

CONCLUSION

All of our results revealed the epigenetic silencing of SFRP5 by promoter methylation plays pivotal roles in chondrosarcoma development and metastasis through SFRP5/Wnt/β-catenin signaling axis. Modulation of their levels may serve as potential targets and diagnostic tools for novel therapeutic strategies of chondrosarcoma.

Secreted frizzled-related protein 5 protects against oxidative stress-induced apoptosis in human aortic endothelial cells via downregulation of Bax

This study was undertaken to determine the role of secreted frizzled-related protein 5 (SFRP5) in endothelial oxidative injury. Human aortic endothelial cells (HAECs) were exposed to different oxidative stimuli and examined for SFRP5 expression. The effects of SFRP5 overexpression and knockdown on cell viability, apoptosis, and reactive oxygen species production were measured. HAECs treated with angiotensin (Ang) II (1 μM) or oxidized low-density lipoprotein (oxLDL) (150 μg/mL) showed a significant increase in SFRP5 expression. Overexpression of SFRP5 significantly attenuated the viability suppression and apoptosis induction by Ang II and oxLDL, whereas the knockdown of SFRP5 exerted opposite effects. Overexpression of SFRP5 prevented ROS formation and β-catenin activation and reduced Bax expression. Co-expression of Bax significantly reversed the anti-apoptotic effect of SFRP5 overexpression, whereas knockdown of Bax restrained Ang II- and oxLDL-induced apoptosis in HAECs. Taken together, SFRP5 confers protection against oxidative stress-induced apoptosis through inhibition of β-catenin activation and downregulation of Bax.

Recombinant SFRP5 protein significantly alleviated intrahepatic inflammation of nonalcoholic steatohepatitis

Background

Secreted frizzled-related protein 5 (SFRP5) is an anti-inflammatory adipokine modulating metabolism dysfunction. This study aims to observe the effect of recombinant SFRP5 protein on nonalcoholic steatohepatitis (NASH).

Methods

We set up a prokaryotic expression system and purified the recombinant SFRP5 protein. Recombinant SFRP5 protein was further identified by SDS-PAGE, western blot, high performance liquid chromatography (HPLC), protein mass spectrometry and in vitro Wnt5a-binding test. NASH mouse model was induced by methionine and choline deficient diet (MCDD) for 2 weeks. SFRP5 treatment group received intraperitoneal injection with a dosage of 10μg/kg SFRP5 twice a day for 2 weeks. Saline was used as control. Inflammation and fatty lesion score of liver tissue pathology and serum transaminase level were compared.

Results

The purity of recombinant SFRP5 protein is 90% identified by HPLC. Its molecule size is 36,096.08 tested by mass spectrometry. Recombinant SFRP5 can specifically bind with Wnt5a which verifies its activity in vitro. The endotoxin level of this recombinant protein is 0.01EU/μg-0.1EU/μg and is suitable for animal experiment. SFRP5 can significantly improve liver inflammation (SFRP5 vs. control, 1.40 ± 0.70 vs. 2.00 ± 0.47, P < 0.05) as well as fatty lesion scores (SFRP5 vs. control, 1.40 ± 0.97 vs. 2.20 ± 0.63, P < 0.05), and lower ALT and AST levels. The mRNA expression of proinflammatory adipokines (IL-1β, IL-6, TNFα and MCP-1) in liver was down-regulated significantly after SFRP5 intervention. Immunohistochemistry and quantitative PCR revealed a dramatically down-regulation of F4/80 in liver after SFRP5 treatment.

Conclusions

Recombinant SFRP5 protein significantly alleviated NASH induced by MCDD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-017-0208-0) contains supplementary material, which is available to authorized users.

Cloning and Expression of SFRP5 in Tibetan Chicken and its Relationship with IMF Deposition

Secreted frizzled related protein 5 (SFRP5), an anti-inflammatory adipokine, is relevant to the adipocyte differentiation. In order to clarify its role in regulating intramuscular fat (IMF) deposition in Tibetan chicken, the full-length sequence of the Tibetan chicken SFRP5 gene was cloned. The relative expression of SFRP5 gene was detected using quantitative RT-PCR in various tissues of 154 days old Tibetan chicken, as well as in breast muscle, thigh muscle, and adipose tissue at different growth stages. The results showed that SFRP5 gene was expressed in all examined tissues but highly enriched in adipose tissue. Temporal expression profile showed that the expression of SFRP5 was gradually decreased in breast muscle, but was fluctuated in thigh muscle and adipose tissue with the growth of Tibetan chicken. Furthermore, correlation analysis demonstrated that the expression of SFRP5 in breast muscle, thigh muscle and adipose tissue was correlated with IMF content at different levels. The results indicated that Tibetan chicken SFRP5 is involved in IMF deposition.

Gene methylation profiles as prognostic markers in ovarian clear cell and endometrioid adenocarcinomas

Ovarian cancer is a cancer of high mortality. Aberrant gene methylation of tumor suppressor genes has been shown to be related to the development of malignancy. This study aimed to investigate the methylation of various genes in ovarian clear cell adenocarcinoma (OCCA) and ovarian endometrioid adenocarcinoma (OEA) and evaluate methylation biomarkers in terms of patient chemo-response and outcome. Eight candidate genes from 66 OCCA and 51 OEA patients were evaluated by methylation-specific polymerase chain reaction and capillary electrophoresis. Clinico-pathological parameters and patient outcomes were analyzed. The frequencies of gene methylation in RASSF1A (79% vs. 59%, p=0.025), E-cadherin (30% vs. 10%, p=0.011), and DLEC1 (71% vs. 43%, p=0.003) were higher in the patients with OCCA than in those with OEA. The chemo-resistant group had a significantly higher percentage of E-cadherin methylation (36.7% vs. 16.1%, p=0.036) than the chemo-sensitive group. In multivariate analysis (log-rank test), advanced stage (4.79 [2.10-10.94], p<0.001) was the only risk factor for mortality. Those with methylation of more than two out of three genes (E-cadherin, DLEC1, and SFRP5) had a shorter disease-free survival (1.89 [1.07-3.32], p=0.028) and overall survival (3.29 [1.57-6.87], p=0.002) than those with methylation of one or no gene. In advanced-stage malignancies, those with more than two out of the three gene methylations also had a shorter overall survival (3.86 [1.63-9.09], p=0.002) than those with methylation of only one or no gene. Patients with OCCA have different patterns of gene methylation than those with OEA. Methylation of the E-cadherin, DLEC1 and SFRP5 genes can be a prognostic biomarker for OCCA and OEA.

Gene methylation in gastric cancer

Gastric cancer is one of the most common malignancies and remains the second leading cause of cancer-related death worldwide. Over 70% of new cases and deaths occur in developing countries. In the early years of the molecular biology revolution, cancer research mainly focuses on genetic alterations, including gastric cancer. Epigenetic mechanisms are essential for normal development and maintenance of tissue-specific gene expression patterns in mammals. Disruption of epigenetic processes can lead to altered gene function and malignant cellular transformation. Recent advancements in the rapidly evolving field of cancer epigenetics have shown extensive reprogramming of every component of the epigenetic machinery in cancer, including DNA methylation, histone modifications, nucleosome positioning, noncoding RNAs, and microRNAs. Aberrant DNA methylation in the promoter regions of gene, which leads to inactivation of tumor suppressor and other cancer-related genes in cancer cells, is the most well-defined epigenetic hallmark in gastric cancer. The advantages of gene methylation as a target for detection and diagnosis of cancer in biopsy specimens and non-invasive body fluids such as serum and gastric washes have led to many studies of application in gastric cancer. This review focuses on the most common and important phenomenon of epigenetics, DNA methylation, in gastric cancer and illustrates the impact epigenetics has had on this field.