Effects Of Apigenin Research Articles

Apigenin suppresses PD-L1 expression in melanoma and host dendritic cells to elicit synergistic therapeutic effects

BackgroundThe PD-L1/PD-1 pathway blockade-mediated immune therapy has shown promising efficacy in the treatment of multiple cancers including melanoma. The present study investigated the effects of the flavonoid apigenin on the PD-L1 expression and the tumorigenesis of melanoma.MethodsThe influence of flavonoids on melanoma cell growth and apoptosis was investigated using cell proliferation and flow cytometric analyses. The differential IFN-γ-induced PD-L1 expression and STAT1 activation were examined in curcumin and apigenin-treated melanoma cells using immunoblotting or immunofluorescence assays. The effects of flavonoid treatment on melanoma sensitivity towards T cells were investigated using Jurkat cell killing, cytotoxicity, cell viability, and IL-2 secretion assays. Melanoma xenograft mouse model was used to assess the impact of flavonoids on tumorigenesis in vivo. Human peripheral blood mononuclear cells were used to examine the influence of flavonoids on PD-L1 expression in dendritic cells and cytotoxicity of cocultured cytokine-induced killer cells by cell killing assays.ResultsCurcumin and apigenin showed growth-suppressive and pro-apoptotic effects on melanoma cells. The IFN-γ-induced PD-L1 upregulation was significantly inhibited by flavonoids, especially apigenin, with correlated reductions in STAT1 phosphorylation. Apigenin-treated A375 cells exhibited increased sensitivity towards T cell-mediated killing. Apigenin also strongly inhibited A375 melanoma xenograft growth in vivo, with enhanced T cell infiltration into tumor tissues. PD-L1 expression in dendritic cells was reduced by apigenin, which potentiated the cytotoxicity of cocultured cytokine-induced killer cells against melanoma cells.ConclusionsApigenin restricted melanoma growth through multiple mechanisms, among which its suppression of PD-L1 expression exerted a dual effect via regulating both tumor and antigen presenting cells. Our findings provide novel insights into the anticancer effects of apigenin and might have potential clinical implications.

Apigenin exerts anticancer effects on human cervical cancer cells via induction of apoptosis and regulation of Raf/MEK/ERK signalling pathway

Purpose: To investigate the anticancer activity of apigenin on human cervical cancer cells. Methods: The anti-proliferative effects of apigenin on HeLa cervical cancer cells were determined by 3-(4,5-dimethylthiazol-2-yl)- )-2,5-diphenyltetrazolium bromide (MTT) and clonogenic assays, while its effect on apoptosis was assayed by DAPI and annexin V/PI double staining. Expression of proteins was assessed by immunoblotting. Results: Apigenin exerted anticancer effects on HeLa cervical cancer cells with an IC 50 of 15 μM, and also reduced the colony formation of HeLa cells. These antiproliferative effects were due to induction of apoptosis as indicated by DAPI and annexin V/PI staining. Apigenin altered Bax/Bcl-2 ratio, thereby triggering apoptosis, and also inhibited the Raf/MEK/ERK signalling pathway. Conclusion: These results indicate that apigenin suppresses the growth of cervical cancer cells and may prove to be an important molecule for the treatment of cervical cancer. Keywords: Cervical cancer, Apigenin, Apoptosis, Bax

Effect of apigenin on apoptosis induced by renal ischemia/reperfusion injury in vivo and in vitro

Objectives: This study aims to investigate the effects and molecular mechanisms of apigenin (ApI) on renal ischemia/reperfusion (I/R) injury in vivo and in vitro. Methods: In vivo, the left renal artery was clamped for 45 min and the right kidney was removed to study renal I/R injury on Sprague-Dawley (SD) rats. ApI was injected at 60 min before renal ischemia. In vitro, renal tubular epithelial cells (HK-2) were pretreated with or without ApI (20 uM) for 60 min and then treated with hypoxia/reoxygenation (H/R). Renal function, histology, cells apoptosis, and cell viability were tested. Furthermore, the potential molecular mechanisms were assessed. Results: ApI pretreatment could significantly alleviated the renal function and the pathological damage as well as cells apoptosis after I/R injury. Meanwhile, ApI treatment protects H/R induced HK-2 cell apoptosis in vitro. The results of Western blot showed that ApI significantly increased the expressions of B-cell lymphoma 2 (Bcl-2) and phosphor-AKt (p-AKt), Phosphoinositide 3-kinase (PI3K), while down-regulated the expressions of Caspase3 and Bax induced by H/R injury. Conclusions: ApI pretreatment can protect renal function against I/R injury and prevent renal tubular cells from apoptosis in vivo and in vitro which might through PI3K/Akt mediated mitochondria-dependent apoptosis signaling pathway.

A1935 Modulation of TRPV4 by apigenin ameliorates renal fibrosis in DOCA salt hypertensive rats

Objectives: Hypertension contributes to chronic renal damage. Apigenin, an effective anti-hypertensive flavone, acts as antagonist of transient receptor potential vanilloid 4 (TRPV4). Here, we aimed to investigate whether apigenin ameliorates hypertension-induced renal fibrosis and its underlying mechanism. Methods: Male Sprague-Dawley rats, 2-month-old TRPV4 knockout mice (TRPV4−/−) and their wild-type littermates were used to established deoxycorticosterone acetate (DOCA)–salt-induced hypertension model and received 0.2% apigenin diet for 4 weeks. The tail-cuff blood pressure (BP) was measured. Renal fibrosis was assessed by Histological staining and protein levels of fibrotic markers TGF-β1, p-Smad2/3, CTGF, COL1a1, and COL3a1 detected by western blot. Expression of TRPV4 was analyzed in kidney and renal mesangial cell. Cytosolic free Ca2+ was measured by fluorospectrometers. Results: Apigenin signifcantly attenuated hypertension-induced renal fibrosis, which was accompanied by reduced expression of TGF-β1/Smad2/3 signaling proteins. The inhibitory effect of apigenin on renal fibrosis is independent of blood pressure reduction. Immunochemistry, cell-attached patch clamp and fluorescent Ca2+ imaging results indicated that TRPV4 was expressed and activated by apigenin in both the kidney and renal cells. Importantly, knockout of TRPV4 in mice abolished the beneficial effects of apigenin that were observed in the DOCA–salt hypertensive rats. Additionally, apigenin directly inhibited activation of the TGF-β1/Smad2/3 signaling pathway in different renal tissues through activation of TRPV4 regardless of the type of pro-fibrotic stimulus. Conclusion: Dietary apigenin ameliorates hypertension-induced renal fibrosis through directly inhibiting the TGF-β1/Smad2/3 pathway in a TRPV4-dependent manner.

The significant impact of apigenin on different aspects of autoimmune disease.

Autoimmune diseases are among the highest diseases to diagnose and treat. The current "gold standard" of care for these diseases is immunosuppressive drugs which interfere with overall immune responses; their long-term high-dose treatments would expose the patient to opportunistic, life-threatening and long-term malignant infections. Considering the side effects and toxicity of these drug and also the beneficial effects of herbal compounds among their consumers, the professional investigation on the exact mechanism of the plant's major element has grown much attention in the last years. Apigenin as an extracting compound of plants, such as parsley and celery, which has a variety of biological effects, such as anti-inflammatory, anti-cancer and antioxidant effects. This review is intended to summarize the various effects of Apigenin on several autoimmune diseases which have been worked on so far. The pluralization of the obtained results has revealed Apigenin's effects on pro-inflammatory cytokines such as IL-1β, chemokines such as ICAM-1, immune cells proliferation such as T cells, apoptosis, and various signaling pathways. According to these preclinical findings, we recommend that further robust unbiased studies should be done to use Apigenin as a supplementary or therapeutic element in autoimmune disease.

Apigenin alleviates TGF-β1-induced nasal mucosa remodeling by inhibiting MAPK / NF-kB signaling pathways in chronic rhinosinusitis.

BackgroundChronic rhinosinusitis is involved in tissue remodeling of nasal mucosa such as nasal myofibroblast differentiation and extracellular matrix production. Apigenin (4’,5,7-trihydroxyflavone) is a bioflavonoid compound and has anti-tissue remodeling characteristics. The aims of this study were to evaluate the effect of apigenin on TGF-β1-induced myofibroblast differentiation and extracellular matrix accumulation and to determine the underlying mechanism.MethodsNasal fibroblasts and ex vivo nasal inferior turbinate tissues were stimulated with TGF-β1 with or without apigenin. The expression levels of α-SMA, fibronectin and collagen type I were determined by real-time PCR, western blot and immunocytochemical staining. Mitogen-activated protein kinase (MAPK) phosphorylation induced by TGF-β1 were determined by western blot analysis. The transcriptional activity of NF-κB was measured by luciferase assay. Migration effects of fibroblasts were evaluated by wound scratch and transwell migration assay. Contractile activity was determined by collagen gel contraction assay.ResultsThe expression levels of α-SMA, fibronectin, and collagen type I significantly increased in TGF-β1-stimulated nasal fibroblasts. In TGF-β1-stimulated nasal fibroblasts, apigenin inhibited the expressions of α-SMA, fibronectin, and collagen type I. Inhibitors of MAPK (p-38, JNK) and NF-κB blocked the expression of α-SMA, fibronectin and collagen type I. Apigenin suppressed the activation of MAPK (p-38, JNK) and NF-κB induced by TGF-β1 treatment. Apigenin also inhibited the functional activity of fibroblasts by reducing the migration and collagen contractile activities.ConclusionsThese results suggests the possible use of apigenin as a chronic rhinosinusitis therapeutic agent which can suppress tissue remodeling in nasal mucosa.

Preventive effect of apigenin against isoproterenol-induced apoptosis in cardiomyoblasts.

We investigated the effect of apigenin, a dietary flavonoid, on isoproterenol hydrochloride (ISO)-induced apoptotic signaling in cardiomyoblast H9C2 cells. The results showed that apigenin treatment (10 µM) prevented ISO (31.25 μM)-induced lipid peroxidative levels and antioxidants status in H9C2 cells. Furthermore, apigenin inhibited expression of inflammatory markers in ISO-treated cells. In addition, apigenin prevented ISO-induced DNA damage and apoptotic signaling through modulating the expression of Bax, caspase-3, -8 and -9, cytochrome c, and Fas proteins in H9C2 cells. It is concluded that apigenin prevents ISO-induced antioxidants depletion, oxidative DNA damage, inflammatory, and apoptotic signaling in H9C2 cells. Thus, the present results demonstrated that apigenin has a cardioprotective effect on cardiomyoblasts cells.

Apigenin Inhibits UVB-Induced Skin Carcinogenesis: The Role of Thrombospondin-1 as an Anti-Inflammatory Factor

We have previously demonstrated that apigenin promotes the expression of antiangiogenic protein thrombospondin-1 (TSP1) via a mechanism driven by mRNA-binding protein HuR. Here, we generated a novel mouse model with whole-body THBS-1 gene knockout on SKH-1 genetic background, which allows studies of UVB-induced acute skin damage and carcinogenesis and tests TSP1 involvement in apigenin's anticancer effects. Apigenin significantly inhibited UVB-induced carcinogenesis in the wild-type (WT) animals but not in TSP1 KO (TKO) mice, suggesting that TSP1 is a critical component of apigenin's chemopreventive function in UVB-induced skin cancer. Importantly, TKO mice presented with the elevated cutaneous inflammation at baseline, which was manifested by increased inflammatory infiltrates (neutrophils and macrophages) and elevated levels of the two key inflammatory cytokines, IL-6 and IL-12. In agreement, maintaining normal TSP1 expression in the UVB-irradiated skin of WT mice using topical apigenin application caused a marked decrease of circulating inflammatory cytokines. Finally, TKO mice showed an altered population dynamics of the bone marrow myeloid progenitor cells (CD11b+), with dramatic expansion of the population of neutrophil progenitors (Ly6ClowLy6Ghigh) compared to the WT control. Our results indicate that the cutaneous tumor suppressor TSP1 is a critical mediator of the in vivo anticancer effect of apigenin in skin, specifically of its anti-inflammatory action.

Protective effects of apigenin against 3-MCPD-induced renal injury in rat

Apigenin (API) is a kind of important flavonoid present in temperate and tropical fruit and vegetables, especially the celery. It exerts anticancer, anti-bacterial, anti-viral, anti-inflammatory, anti-oxidation properties. In the present study, the mechanism of protective action of apigenin on 3-chloro-1, 2-propanediol (3-MCPD)-induced renal injury was investigated in rat. Sprague-Dawley (SD) rats were divided into five groups: control group (ultrapure water treated), CMC group (sodium carboxymethylcellulose treated), 3-MCPD treatment group (30 mg/kg body weight/day), 3-MCPD plus API co-treatment group (20, 40 mg/kg body weight/day). The results showed that API significantly reduced renal function markers, serum creatinine and urea nitrogen content. Besides, the renal tissue lesion in 3-MCPD treatment group was restored by API to some extent. We indicated that API exerted renoprotective effect by modulating oxidative phosphorylation especially up-regulated the expressions of ATP6 and ATP8, re-establishing mitochondrial membrane potential (MMP), relieving the increase of Bax/Bcl2 ratio, reducing cytochrome c release, thus inhibiting the activation of Caspase 9 and Caspase 3. In conclusion, apigenin possesses excellent protective effect against 3-MCPD-induced renal injury by modulating mitochondria dependent Caspase cascade pathway.

Apigenin suppresses mouse peritoneal fibrosis by down-regulating miR34a expression

Peritoneal fibrosis is a severe side-effect of chronic peritoneal dialysis in patients with end-stage renal disease, but not enough effective therapeutic drugs are currently available in clinics. The aim of this study was to evaluate the effects of apigenin and miRNA on the progression of peritoneal fibrosis. We treated isolated mouse mesothelial peritoneal cells (MMCs) with high glucose (HG), to induce fibrosis. We used qRT-PCR and Western blotting to measure the expressions of multiple epithelial-mesenchymal transition (EMT) biomarkers, like E-cadherin, transcription termination factor (TTF), N-cadherin and vimentin, as well as several apoptosis and autophagy biomarkers. We determined the IC50 of apigenin on MMC fibrosis. We also used qRT-PCR to assess the expressions of miRNAs in MMC fibrosis. In addition, we by used the CCK8 assay, Hoechest staining and flow cytometry, to measure cell viability and proliferation rates. We successfully induced fibrosis using high glucose (HG) treatment in MMCs. This was further validated by the observed changes in E-cadherin, TTF, N-cadherin and vimentin expression levels. We also observed highly elevated expression levels of miR34a during HG-induced MMC fibrosis. Apigenin treatment induced a significant decrease in miR34a expression levels in HG-treated MMCs. Moreover, both apigenin treatment and miR34a depletion, as well as their combination, significantly promoted proliferation and suppressed apoptosis of MMCs treated with high glucose. This was accompanied with a corresponding alteration in expressions of EMT, apoptosis and autophagy biomarkers. In summary, apigenin effectively inhibits mouse mesothelial peritoneal cell fibrosis induced by high glucose, and this is, at least partially mediated by the suppression of miR34a expression.

Apigenin Suppresses the IL-1β-Induced Expression of the Urokinase-Type Plasminogen Activator Receptor by Inhibiting MAPK-Mediated AP-1 and NF-κB Signaling in Human Bladder Cancer T24 Cells.

The urokinase-type plasminogen activator receptor (uPAR), a glycoprotein localized on the cell surface with a glycosylphosphatidylinositol anchor, plays a crucial role in cell invasion, and the metastasis of several cancers, including bladder cancer, and its expression are significantly negatively correlated with patient survival rates. Apigenin, a naturally produced phytochemical compound found in fruits, vegetables, and plant leaves, has been shown to mediate a variety of cancer-metastasis-related molecules in various cancers. The effect of apigenin on uPAR expression is still unknown. In this study, we examined the effects of apigenin on IL-1β-induced uPAR expression and investigated its potential mechanisms. We discovered in this study that IL-1β could remarkably induce uPAR expression in bladder cancer T24 cells and that apigenin-inhibited IL-1β could induce uPAR expression concentration-dependently. Interestingly, NF-κB and AP-1 transcription factors were critically required for IL-1β-induced high uPAR expression. Apigenin suppressed the transcriptional activity of both AP-1 and NF-κB by inhibiting ERK1/2 and JNK signaling pathways. These results suggest that apigenin can exert anti-invasion effects by inhibiting uPAR expression via mediating (ERK1/2, JNK)/AP-1 and (ERK1/2, JNK)/NF-κB signaling pathways in human T24 cells. Our present study generated novel and valuable biological insight into anti-invasion through treatment with a small native compound.

Co-administrating apigenin in a high-cholesterol diet prevents hypercholesterolaemia in golden hamsters.

Hypercholesterolaemia is a major risk factor for developing atherosclerosis. Increased consumption of fruits and vegetables is recommended to hypercholesterolaemic patients. In this study, the hypocholesterolaemic effect of apigenin and luteolin was evaluated in a hamster model. Hamsters were put on a high-cholesterol diet for 9weeks, and apigenin or luteolin was administered in the diet at 60 and 300ppm. Both apigenin and luteolin supplementations could attenuate the aorta plaque formation by 30% and 20%, respectively. Apigenin-fed hamsters at both dosages displayed a 1.5-fold increase in hepatic Ldlr expression and a 40% reduction in non-HDL cholesterol level as compared with those in the control fed a high-cholesterol (HC) diet. Besides, faecal elimination of cholesterol was facilitated by 20% in the hamsters with high apigenin consumption. Suppressing the expression of the cholesterol transporter ncp1l1 in the intestinal mucosa could block the cholesterol absorption and promote its elimination. The differential regulations of ncp1l1 and Ldlr appeared to be the underlying hypocholesterolaemic mechanism of apigenin in this model system. Luteolin supplementation, on the other hand, had no effect on the blood cholesterol. This study illustrated that dietary administration of apigenin attenuated HC feeding-induced hypercholesterolemia in hamsters.

Apigenin prevents metabolic syndrome in high-fructose diet-fed mice by Keap1-Nrf2 pathway.

Chronic dietary high fructose leads to various kinds of undesirable metabolic effects. Apigenin, a naturally occurring plant flavone, is plentiful in fruits and vegetables. The aim of this study was to identify the protective effects of apigenin on metabolic syndrome and elucidate potential underlying mechanisms. The animal model was established by 4-weeks high fructose feeding. Insulin resistance was estimated by oral glucose tolerance test and homeostasis model assessment-insulin resistance index. Liver function was evaluated by serum AST and ALT, hepatic histopathological alternation, and lipid accumulation in the liver. The alterations of lipid profile was evaluated by TG, TC, LDL-C and HDL-C levels in serum. Administration of apigenin exerted beneficial effects through improving insulin resistance, alleviating liver injury, and inhibiting the alterations of lipid profile in high fructose-fed mice. In addition, apigenin potently facilitated the accumulation of Nrf2 nuclear translocation and accompanied by increasing HO-1 and NQO1 protein expressions, which are responsible for attenuating oxidative stress. Molecular docking results demonstrated that potential interaction of apigenin with the Nrf2-binding site in the Keap1 protein. In summary, we demonstrated that apigenin prevented high fructose-induced metabolic syndrome probably by inhibiting binding of Keap1 to Nrf2, and thus Nrf2 nuclear translocation, subsequently resulting in increased the expressions of anti-oxidative genes including HO-1 and NQO1.

Apigenin suppresses the apoptosis of H9C2 rat cardiomyocytes subjected to myocardial ischemia‑reperfusion injury via upregulation of the PI3K/Akt pathway.

Apigenin, a flavonoid with multiple physiological and pharmacological activities, is associated with the prevention of cardiovascular diseases. The present study aimed to examine the roles and mechanisms of apigenin in the apoptosis of H9C2 rat cardiomyocytes, which were subjected to myocardial ischemia-reperfusion (MI/R) injury. Cell viability, reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and cellular apoptosis were evaluated using cell counting kit-8 assays and flow cytometry. The content/activity of oxidative stress markers was determined using commercial kits. Western blot analysis and reverse transcription-quantitative polymerase chain reaction assays were used to measure protein and mRNA expression, respectively. The results demonstrated that apigenin had limited cytotoxicity on the viability of H9C2 rat cardiomyocytes. Apigenin reduced the oxidative stress, ROS production and cellular apoptotic capacity of MI/R-induced H9C2 cells. Apigenin additionally increased the MMP level of MI/R-induced H9C2 cells. Furthermore, apigenin modulated apoptosis-associated protein expression and phosphatidylinositol 3′-kinase (PI3K)/RAC-α serine/threonine-protein kinase (Akt) signaling in MI/R-induced H9C2 cells. Treatment with LY294002 reversed the anti-apoptotic effect of apigenin. In conclusion, apigenin suppressed the apoptosis of H9C2 cells that were subjected to MI/R injury by activating the PI3K/Akt pathway. It was suggested that apigenin may be effective as an MI/R therapy.

Effects of Apigenin and Apigenin- Loaded Nanogel on Induction of Apoptosis in Human Chronic Myeloid Leukemia Cells.

Background: Diet plays an important role in cancer prevention. Apigenin, a flavonoid with thechemical formula C15H10O5 , is abundantly present in vegetables. Vegetarian foods containing flavonoids are rich sources of bioactive compounds. Flavonoids have been utilized in herbal treatment. Nanogels are drug delivery systems based on polymers and are used in tissue engineering and for drug delivery. This study was conducted to compare the effects of apigenin and a nanodrug on the viability of the K562 cell line of chronic myeloid leukemia at different durations under laboratory conditions. Materials and Methods: Chitosan was first dissolved in 1% acetic acid, and ethylene dichloride EDC and NHS were added to the solution. Then, the nanodrug was prepared by loading apigenin into stearate–chitosan nanogel (scs nanogel), and its physical and morphological characteristics were evaluated by TEM, DLS, and FTIR. Trypan blue staining, MTT assay, and flow cytometry were used to analyze the effects of various concentrations of apigenin and apigenin-loaded chitosan–stearate nanogel (APG–SCS) at 24, 48, and 72 h after they were applied to the K562 cell line. Results: The diameter of the nanodrug particles was measured using DLS and confirmed by TEM. The K562 cells treated with APG–SCS and with apigenin exhibited significant differences compared with the control (P < 0.05). Apoptosis was detected by flow cytometry. Conclusion: This study showed that the toxic effects of apigenin and the nanodrug improved with increasing concentrations and exposure durations compared to those in the control.The toxic effect of apigenin loaded into the stearate-chitosan nanogel was greater than apigenin, and the toxic effects of both materials were greater compared to the control under laboratory conditions.

Effects of Apigenin and Apigenin- Loaded Nanogel on Induction of Apoptosis in Human Chronic Myeloid Leukemia Cells

Background: Diet plays an important role in cancer prevention. Apigenin, a flavonoid with thechemical formula C15H10O5, is abundantly present in vegetables. Vegetarian foods containing flavonoids are rich sources of bioactive compounds. Flavonoids have been utilized in herbal treatment. Nanogels are drug delivery systems based on polymers and are used in tissue engineering and for drug delivery. This study was conducted to compare the effects of apigenin and a nanodrug on the viability of the K562 cell line of chronic myeloid leukemia at different durations under laboratory conditions. Materials and Methods: Chitosan was first dissolved in 1% acetic acid, and ethylene dichloride EDC and NHS were added to the solution. Then, the nanodrug was prepared by loading apigenin into stearate–chitosan nanogel (scs nanogel), and its physical and morphological characteristics were evaluated by TEM, DLS, and FTIR. Trypan blue staining, MTT assay, and flow cytometry were used to analyze the effects of various concentrations of apigenin and apigenin-loaded chitosan–stearate nanogel (APG–SCS) at 24, 48, and 72 h after they were applied to the K562 cell line. Results: The diameter of the nanodrug particles was measured using DLS and confirmed by TEM. The K562 cells treated with APG–SCS and with apigenin exhibited significant differences compared with the control (P &lt; 0.05). Apoptosis was detected by flow cytometry. Conclusion: This study showed that the toxic effects of apigenin and the nanodrug improved with increasing concentrations and exposure durations compared to those in the control.The toxic effect of apigenin loaded into the stearate-chitosan nanogel was greater than apigenin, and the toxic effects of both materials were greater compared to the control under laboratory conditions.[GMJ.2018;7:e1008]

Apigenin inhibits C5a-induced proliferation of human nasopharyngeal carcinoma cells through down-regulation of C5aR.

Complement 5a (C5a) is able to induce the proliferation of human nasopharyngeal carcinoma (NPC) cells. Therefore, an effective method or drug that can specifically inhibit C5a-induced proliferation of human NPC cells needs to be developed. Reportedly, Apigenin has antiproliferative effects on a variety of cancer cells. However, the effect of Apigenin on NPC cell proliferation and its underlying mechanism are still unclear. Herein, the present study aimed to evaluate the effect of Apigenin on C5a-induced proliferation of human NPC cells and its possible mechanism through down-regulation of C5aR. We revealed that Apigenin in vitro could not only inhibit proliferation of NPC cells and but also reduce the expression of C5aR and P300/CBP-associated factor (PCAF) as well as the activation of signal transducer and activator of transcription 3 (STAT3) in NPC cells. Furthermore, Apigenin reduced the proliferation of human NPC cells triggered by C5a through negative regulation of C5aR/PCAF/STAT3 axis. These might provide a new insight into the function of Apigenin in cancer treatment, and also provide a potential strategy for treating human NPC through inhibition of C5aR expression on cancer cells.

Combined effect of apigenin and ferulic acid on frozen-thawed boar sperm quality.

The main aim of the present study was to evaluate the cryoprotective effect of apigenin (AP) and ferulic acid (FA) on boar sperm during cryopreservation. AP and FA were both demonstrated to be high-efficiency antioxidants and had not previously been used to protect sperm from cryodamage. As boar sperm is sensitive to oxidative stress, suitable antioxidants are still needed for improving frozen-thawed sperm quality. With this purpose, semen samples coming from five boars were used in this study. Ejaculates of five boars were mixed and split into 16 aliquots, in which different doses of AP and FA were added separately or together. The motility, the plasma membrane integrity, the mitochondrial activity, the acrosomal integrity, the antioxidase activities and the malondialdehyde concentration of the frozen-thawed boar sperm were assessed. The results suggested that both AP and FA significantly improved the frozen-thawed boar sperm quality in all these aspects when they were added to the freezing extender separately, while the highest improvement was recorded when the extender was supplemented with 0.1mmol/L AP plus 0.15mmol/L FA. These findings demonstrated that supplementation of freezing extender with both AP and FA had a combined, beneficial effect on frozen-thawed boar sperm.

Inhibition of PI3K/Akt/mTOR pathway by apigenin induces apoptosis and autophagy in hepatocellular carcinoma cells

Apigenin is a dietary flavonoid with known antioxidant and antitumor effects against several types of cancers by promoting cell death and inducing cell cycle arrest. Apigenin also regulates a variety of intracellular signal transduction pathways during apoptosis or autophagy. However, the precise mechanism underlying the anticancer effects of apigenin in liver cancer remains poorly understood. In this study, we demonstrated that apigenin has anticancer activity against hepatocellular carcinoma cells. Apigenin inhibited the cell growth and induced cell death in a dose- and time-dependent manner in HepG2 cells. We found that apigenin treatment increased the expression of LC3-II and the number of GFP-LC3 puncta. Moreover, inhibition of autophagy with 3-MA and Atg5 gene silencing strengthened apigenin-induced proliferation inhibition and apoptosis. Our data has indicated that apigenin-induced autophagy has a protective effect against cell death. Additionally, apigenin induced apoptosis and autophagy through inhibition of PI3K/Akt/mTOR pathway. Most importantly, in vivo data showed that administration of apigenin decreased tumor growth and autophagy inhibition by 3-MA significantly enhanced the anticancer effect of apigenin. Collectively, our results reveal that apigenin inhibits cell proliferation and induces autophagy via suppressing the PI3K/Akt/mTOR pathway. Our results also suggest combination of autophagy inhibitors and apigenin would be a potential chemotherapeutic strategy against hepatocellular carcinoma.

Protective Effect of Apigenin on Acrylonitrile-Induced Inflammation and Apoptosis in Testicular Cells via the NF-κB Pathway in Rats.

Apigenin (AP) as a plant flavonoid is found to attenuate acrylonitrile (ACN) toxicity by reducing ROS production and inhibiting apoptosis. Therefore, the present study aimed to evaluate the role of AP on ACN-induced inflammation and apoptosis in germ cells and whether it is through the NF-κB signaling pathway. AP increased the concentrations of lactate dehydrogenase isozyme (LDH) and sorbitol dehydrogenase (SDH), while the concentrations of interleukin β (IL-1β), tumor-necrosis factor-α (TNF-α), and interleukin-6 (IL-6) were significantly reduced. AP could downregulate the expression of the nuclear factor of kappa B (NF-κB) and inhibit phosphorylation of the inhibitory κBα (IκBα). Cleaved caspase-3 was also upregulated by AP, and the apoptotic were less than those in the ACN group. These results suggest that AP might improve maturation and energy metabolism of testes, inhibit NF-κB activation. Then AP could further downregulate NF-κB signal and inhibit the germ cell apoptosis and reduce inflammatory caused by ACN.