Reactive oxygen species involved in prenylflavonoids, icariin and icaritin, initiating cardiac differentiation of mouse embryonic stem cells

Natural STAT3 Inhibitors for Cancer Treatment: A Comprehensive Literature Review

Cancer is one of the leading causes of mortality and morbidity worldwide, affecting millions of people physically and financially every year. Over time, many anticancer treatments have been proposed and studied, including synthetic compound consumption, surgical procedures, or grueling chemotherapy. Although these treatments have improved the daily life quality of patients and increased their survival rate and life expectancy, they have also shown significant drawbacks, including staggering costs, multiple side effects, and difficulty in compliance and adherence to treatment. Therefore, natural compounds have been considered a possible key to overcoming these problems in recent years, and thorough research has been done to assess their effectiveness. In these studies, scientists have discovered a meaningful interaction between several natural materials and signal transducer and activator of transcription 3 molecules. STAT3 is a transcriptional protein that is vital for cell growth and survival. Mechanistic studies have established that activated STAT3 can increase cancer cell proliferation and invasion while reducing anticancer immunity. Thus, inhibiting STAT3 signaling by natural compounds has become one of the favorite research topics and an attractive target for developing novel cancer treatments. In the present article, we intend to comprehensively review the latest knowledge about the effects of various organic compounds on inhibiting the STAT3 signaling pathway to cure different cancer diseases.

Icaritin: A phytomolecule with enormous pharmacological values

Pharmacological studies on flavonoids have always drawn much interest for many years. Icaritin (ICT), a representative flavone containing an 8-prenyl group, is a principal compound detected in medicinal plants of the genus Epimedum, the family Berberidaceae. Experimental results in the phytochemistry and pharmacology of this molecule are abundant now, but a deep overview has not been carried out. The goal of this review is to provide an insight into the natural observation, biosynthesis, biotransformation, synthesis, pharmacology, and pharmacokinetics of prenyl flavone ICT. The relevant data on ICT was collected from bibliographic sources, like Google Scholar, Web of Science, Sci-Finder, and various published journals. "Icaritin" alone or in combination is the main keyword to seek for references, and references have been updated till now. ICT is among the characteristic phytomolecules of Epimedum plants. Bacteria monitored its biosynthesis and biotransformation, while this agent was rapidly synthesized from phloroglucinol by microwave-assistance Claisen rearrangement. ICT is a potential agent in numerous in vitro and in vivo pharmacological records, which demonstrated its role in cancer treatments via apoptotic-related mechanisms. It also brings in various health benefits since it reduced harmful effects on the liver, lung, heart, bone, blood, and skin, and improved immune responses. Pharmacokinetic outcomes indicated that its metabolic pathway involved hydration, hydroxylation, dehydrogenation, glycosylation, and glucuronidation. Molecule mechanisms of action at a cellular level are predominant, but clinical studies are expected to get more. Structure-activity relationship records seem insufficient, and the studies on nano-combined approaches to improve its soluble property in living bodied medium are needed.

Icaritin inhibits PLK1 to activate DNA damage response in NK/T cell lymphoma and increases sensitivity to GELOX regime

Natural killer/T cell lymphoma (NKTCL) is a highly aggressive subtype of non-Hodgkin lymphoma. Gemcitabine, oxaliplatin, and L-asparaginase (GELOX) is one of the first-line chemotherapy regimens of NKTCL. Yet, the prognosis of NKTCL is poor. Icaritin is an herb-derived monomer from icariin with antitumor effects. We found that icaritin induced proliferation inhibition and apoptosis of NKTCL both in vitro and in vivo. Moreover, icaritin inhibited the dissemination of NKTCL in vivo. RNA sequencing revealed the Polo-like kinase 1 (PLK1) gene and DNA damage response (DDR) as the targets of icaritin. Mechanistically, icaritin inhibited PLK1 to promote checkpoint kinase 2 (Chk2) homodimerization and its T387 phosphorylation, which further activated p53, leading to the activation of the DDR pathway. Moreover, inhibiting PLK1 increased Forkhead box O3a nuclear localization, the latter of which activated ataxia telangiectasia mutated (ATM), an early sensor of DNA damage. Then ATM phosphorylated Chk2 T68 and initiated Chk2 activation. Remarkably, the combined treatment of icaritin and GELOX achieved better antitumor efficacy than single treatment in vivo. In summary, our results proved the efficacy of icaritin treating NKTCL, provided insights into its antitumor molecular mechanism, and revealed the application value of icaritin in facilitating clinical NKTCL treatment.

Antiosteoporosis Effects, Pharmacokinetics, and Drug Delivery Systems of Icaritin: Advances and Prospects

Osteoporosis is a systemic skeletal disorder affecting over 200 million people worldwide and contributes dramatically to global healthcare costs. Available anti-osteoporotic drug treatments including hormone replacement therapy, anabolic agents, and bisphosphonates often cause adverse events which limit their long-term use. Therefore, the application of natural products has been proposed as an alternative therapy strategy. Icaritin (ICT) is not only an enzyme-hydrolyzed product of icariin but also an intestinal metabolite of eight major flavonoids of the traditional Chinese medicinal plant Epimedium with extensive pharmacological activities, such as strengthening the kidney and reinforcing the bone. ICT displays several therapeutic effects, including osteoporosis prevention, neuroprotection, antitumor, cardiovascular protection, anti-inflammation, and immune-protective effect. ICT inhibits bone resorption activity of osteoclasts and stimulates osteogenic differentiation and maturation of bone marrow stromal progenitor cells and osteoblasts. As for the mechanisms of effect, ICT regulates relative activities of two transcription factors Runx2 and PPARγ, determines the differentiation of MSCs into osteoblasts, increases mRNA expression of OPG, and inhibits mRNA expression of RANKL. Poor water solubility, high lipophilicity, and unfavorable pharmacokinetic properties of ICT restrict its anti-osteoporotic effects, and novel drug delivery systems are explored to overcome intrinsic limitations of ICT. The paper focuses on osteogenic effects and mechanisms, pharmacokinetics and delivery systems of ICT, and highlights bone-targeting strategies to concentrate ICT on the ideal specific site of bone. ICT is a promising potential novel therapeutic agent for osteoporosis.

Icariin Promotes In Vitro Cardiomyocyte Proliferation and Differentiation in Human Bone Marrow-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are the excellent candidates in myocardial regeneration given their easy accessibility, low immunogenicity and high potential for cardiomyocyte differentiation. This work focused on investigating the role of icariin, a main active component of the Traditional Chinese herb epimedium, in human bone marrow-derived MSCs (BMSCs) proliferation and differentiation into cardiomyocytes In Vitro. Human BMSCs were cultivated In Vitro, and MTT assay was conducted to measure their proliferation. On this basis, we selected the optimal icariin dose for promoting the proliferation to induce cardiomyocyte differentiation of MSCs, which were pretreated with or without 5-azacytidine (5-Aza). Cardiac-specific cardiac troponin I (cTnI) and connexin 43 (Cx43)-positive cells were detected by immunofluorescent staining. The differentiation ratio of MSCs was examined by flow cytometry. This study measured early cardiac transcription factors (TFs) Nkx2.5 and GATA4 levels through RT-PCR and Western blotting (WB). As a result, icariin increased MSC proliferation dependent on its dose, and the optimal dose was determined to be 80 μg/l. Furthermore, MSCs showed minimal cardiomyogenic differentiation when induced by icariin alone as confirmed by the expression of cardiac-related markers. Moreover, a synergic interaction was observed when icariin and 5-Aza cooperated to induce cardiomyocyte differentiation of MSCs. In conclusion, Icariin stimulates proliferation and facilitates cardiomyocyte differentiation of MSCs In Vitro and may be potentially used as a new method for enhancing the MSCs efficacy in cardiovascular disease.

Anticancer effects of Traditional Chinese Medicine on epithelial-mesenchymal transition（EMT） in breast cancer: Cellular and molecular targets

Breast cancer is a malignant epithelial tumor of ductal or lobular origin. Breast cancer remains the most frequently diagnosed invasive cancer in women and is the leading cause of cancer-associated mortality worldwide. Epithelial-mesenchymal transition (EMT), a phenotypic process of conversion from epithelial to mesenchymal cells, allows tumor cells to acquire infiltration and metastasization properties. Therapies directed at pathways, which are primarily involved in malignant transformation, can lead to clinical implications. In recent years, EMT has gained increasing attention as a potential therapeutic target in cancer therapy. Moreover, for the past few decades, increasing numbers of studies have suggested that Traditional Chinese Medicine(TCM) compounds can significantly inhibit the growth and development of breast cancer cells through the inhibition of EMT in breast cancer cells. This review discusses some essential signaling pathways associated with EMT and summarizes the effects and mechanism of TCM components on that inhibit EMT in breast cancer therapy.

Icaritin inhibits lung cancer-induced osteoclastogenesis by suppressing the expression of IL-6 and TNF-a and through AMPK/mTOR signaling pathway

Bone metastasis is one of the common phenomena in the late stage of lung cancer. Inhibition of bone metastasis can improve the survival of lung cancer patients. However, the current drugs for the treatment of bone metastasis have shown little effect on overall survival. Therefore, there is an urgent necessity to identify novel drugs capable of preventing and treating bone metastasis of lung cancer. Our study determined that icaritin (ICT) can inhibit lung cancer-mediated osteoclastogenesis and induce the apoptosis of osteoclasts. Exposure to ICT increased the activation of adenosine 5'-monophosphate-activated protein kinase (AMPK), reduced the activation of mammalian target of rapamycin (mTOR) and decreased the expression of bcl-2. The bioactivity of ICT on osteoclastogenesis was associated with the regulation of the AMPK/mTOR signaling pathway. Blocking AMPK significantly increased osteoclast differentiation, decreased osteoclast apoptosis and canceled the effects of ICT on the phosphorylation of AMPK as well as the inhibition of mTOR and bcl-2. Furthermore, ICT decreased the levels of IL-6 and TNF-α in osteoclasts, while the AMPK inhibitor compound C significantly abolished the inhibitory effects of ICT on IL-6 and TNF-α. Thus, the present study demonstrated that ICT may be a potential natural agent for the treatment of bone metastasis in patients with lung cancer.

A comparative study on the in vitro and in vivo antitumor efficacy of icaritin and hydrous icaritin nanorods

Icaritin (ICT) and hydrous icaritin (HICT) are two similar flavonoids compounds isolated from Epimedium Genus. This is the first comparative study on their in vitro and in vivo antitumor effects. Nanorods (NRs) were prepared for ICT and HICT by anti-solvent precipitation method using D-alpha tocopherol acid polyethylene glycol succinate (TPGS) as a stabilizer. The prepared ICT-NRs and HICT-NRs had similar diameter (155.5 nm and 201.7 nm), high drug loading content (43.30 ± 0.22% and 41.08 ± 0.19%), excellent stability and a similar sustaining drug release manner. Nanorods improved the in vitro toxicity against 4 different cancer cells in contrast to free ICT or free HICT; however, no significant difference was observed in this regard between ICT-NRs and HICT NRs. In the in vivo study on the anticancer efficacy on MCF-7 and PLC/PRE/5 tumor-bearing mice model, HICR-NRs displayed certain advantage over ICT NRs with higher tumor inhibition rate.

MAFG-driven osteosarcoma cell progression is inhibited by a novel miRNA miR-4660

Osteosarcoma (OS) is the most common primary bone malignancy in the adolescent population. MAFG (v-maf avian musculoaponeurotic fibrosarcoma oncogene homolog G) forms a heterodimer with Nrf2 (NF-E2-related factor 2), binding to antioxidant response element (ARE), which is required for Nrf2 signaling activation. We found that MAFG mRNA and protein expression is significantly elevated in human OS tissues as well as in established and primary human OS cells. In human OS cells, MAGF silencing or knockout (KO) largely inhibited OS cell growth, proliferation, and migration, simultaneously inducing oxidative injury and apoptosis activation. Conversely, ectopic overexpression of MAFG augmented OS cell progression in vitro. MicroRNA-4660 (miR-4660) directly binds the 3′ untranslated region (UTR) of MAFG mRNA in the cytoplasm of OS cells. MAFG 3′ UTR luciferase activity and expression as well as OS cell growth were largely inhibited with forced miR-4660 overexpression but augmented with miR-4660 inhibition. In vivo, MAGF short hairpin RNA (shRNA) or forced overexpression of miR-4660 inhibited subcutaneous OS xenograft growth in severe combined immunodeficient mice. Furthermore, MAFG silencing or miR-4660 overexpression inhibited OS xenograft in situ growth in proximal tibia of the nude mice. In summary, MAFG overexpression-driven OS cell progression is inhibited by miR-4660. The miR-4660-MAFG axis could be novel therapeutic target for human OS.

The Potential Properties of Natural Compounds in Cardiac Stem Cell Activation: Their Role in Myocardial Regeneration

Cardiovascular diseases (CVDs), which include congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, and many other cardiac disorders, cause about 30% of deaths globally; representing one of the main health problems worldwide. Among CVDs, ischemic heart diseases (IHDs) are one of the major causes of morbidity and mortality in the world. The onset of IHDs is essentially due to an unbalance between the metabolic demands of the myocardium and its supply of oxygen and nutrients, coupled with a low regenerative capacity of the heart, which leads to great cardiomyocyte (CM) loss; promoting heart failure (HF) and myocardial infarction (MI). To date, the first strategy recommended to avoid IHDs is prevention in order to reduce the underlying risk factors. In the management of IHDs, traditional therapeutic options are widely used to improve symptoms, attenuate adverse cardiac remodeling, and reduce early mortality rate. However, there are no available treatments that aim to improve cardiac performance by replacing the irreversible damaged cardiomyocytes (CMs). Currently, heart transplantation is the only treatment being carried out for irreversibly damaged CMs. Hence, the discovery of new therapeutic options seems to be necessary. Interestingly, recent experimental evidence suggests that regenerative stem cell medicine could be a useful therapeutic approach to counteract cardiac damage and promote tissue regeneration. To this end, researchers are tasked with answering one main question: how can myocardial regeneration be stimulated? In this regard, natural compounds from plant extracts seem to play a particularly promising role. The present review will summarize the recent advances in our knowledge of stem cell therapy in the management of CVDs; focusing on the main properties and potential mechanisms of natural compounds in stimulating and activating stem cells for myocardial regeneration.

Roles of Reactive Oxygen Species in Cardiac Differentiation, Reprogramming, and Regenerative Therapies

Reactive oxygen species (ROS) have been implicated in mechanisms of heart development and regenerative therapies such as the use of pluripotent stem cells. The roles of ROS mediating cell fate are dependent on the intensity of stimuli, cellular context, and metabolic status. ROS mainly act through several targets (such as kinases and transcription factors) and have diverse roles in different stages of cardiac differentiation, proliferation, and maturation. Therefore, further detailed investigation and characterization of redox signaling will help the understanding of the molecular mechanisms of ROS during different cellular processes and enable the design of targeted strategies to foster cardiac regeneration and functional recovery. In this review, we focus on the roles of ROS in cardiac differentiation as well as transdifferentiation (direct reprogramming). The potential mechanisms are discussed in regard to ROS generation pathways and regulation of downstream targets. Further methodological optimization is required for translational research in order to robustly enhance the generation efficiency of cardiac myocytes through metabolic modulations. Additionally, we highlight the deleterious effect of the host's ROS on graft (donor) cells in a paracrine manner during stem cell-based implantation. This knowledge is important for the development of antioxidant strategies to enhance cell survival and engraftment of tissue engineering-based technologies. Thus, proper timing and level of ROS generation after a myocardial injury need to be tailored to ensure the maximal efficacy of regenerative therapies and avoid undesired damage.

Natural and herbal compounds targeting breast cancer, a review based on cancer stem cells

Cancer stem cells (CSCs) are known as the major reason for therapy resistance. Recently, natural herbal compounds are suggested to have a significant role in inhibiting the breast cancer stem cells (BCSCs). The aim of this study was to explore the effective natural herbal compounds against BCSCs.This review article was designed based on the BCSCs, mechanisms of therapy resistance and natural herbal compounds effective to inhibit their activity. Therefore, Science direct, PubMed and Scopus databases were explored and related original articles were investigated from 2010 to 2019. BCSCs use different mechanisms including special membrane transporters, anti-apoptotic, pro-survival, and self-renewal- related signaling pathways. Natural herbal compounds could disturb these mechanisms, therefore may inhibit or eradicate the BCSCs. Studies show that a broad range of plants, either as a food or medicine, contain anti-cancer agents that phenolic components and their different derivatives share a large quantity. Natural herbal compounds play a pivotal role in the eradication of BCSCs, through the inhibition of biological activities and induction of apoptosis. Although it is necessary to conduct more clinical investigation.

Roles of vitamins in stem cells

Stem cells can differentiate to diverse cell types in our body, and they hold great promises in both basic research and clinical therapies. For specific stem cell types, distinctive nutritional and signaling components are required to maintain the proliferation capacity and differentiation potential in cell culture. Various vitamins play essential roles in stem cell culture to modulate cell survival, proliferation and differentiation. Besides their common nutritional functions, specific vitamins are recently shown to modulate signal transduction and epigenetics. In this article, we will first review classical vitamin functions in both somatic and stem cell cultures. We will then focus on how stem cells could be modulated by vitamins beyond their nutritional roles. We believe that a better understanding of vitamin functions will significantly benefit stem cell research, and help realize their potentials in regenerative medicine.

Anticancer effect of icaritin on prostate cancer via regulating miR-381-3p and its target gene UBE2C

Prostate cancer (PCa) is one of the most common health-related issues in the male individuals of western countries. Icaritin (ICT) is a traditional Chinese herbal medicine that exhibits antitumor efficacy in variety of cancers including PCa. However, the precise function and detailed molecular mechanism of ICT in the regression of PCa remain unclear. Ubiquitin-conjugating enzyme E2C (UBE2C) is an anaphase-promoting complex/cyclosome (APC/C)-specific ubiquitin conjugating enzyme, which acts as an oncogene in PCa progression. The function of ICT in PCa was investigated in transgenic adenocarcinoma mouse prostate (TRAMP) mice using survival analysis, hematoxylin and eosin (HE) staining, TUNEL assay, and immunohistochemistry and in human PCa cell lines using various molecular techniques and functional assays including plasmid construction and transfection. Bioinformatic analyses were performed to identify the interaction between miRNA and UBE2C via the TargetScan algorithm. We demonstrated that ICT inhibited the development and progression of PCa in TRAMP mice by improving the survival rate and tumor differentiation. Furthermore, we found that ICT could significantly inhibit cell proliferation and invasion and induce apoptosis in PCa cells. Consistently, downregulation of UBE2C suppressed the proliferation and invasion of PCa cells. Moreover, a luciferase reporter assay confirmed that UBE2C was a direct target of miR-381-3p. Meanwhile, ICT simultaneously downregulated UBE2C expression and upregulated miR-381-3p levels in human PCa cells. Altogether, our findings provide a strong rationale for the clinical application of ICT as a potential oncotherapeutic agent against PCa via a novel molecular mechanism of regulating the miR-381-3p/UBE2C pathway.

Reactive oxygen species induced by icaritin promote DNA strand breaks and apoptosis in human cervical cancer cells

Increased production of reactive oxygen species (ROS) is a distinct feature of various types of cancer. ROS drive tumor progression and render cancer cells vulnerable to additional oxidative insult. The various natural herb compounds have been shown to induce additional production of ROS in cancer cells, although the physiological implications of ROS under these conditions are not fully determined. In the present study, icaritin, a natural compound derived from the medicinal plants Epimedium, was demonstrated to potently suppresses the proliferation of human HeLa and SiHa cervical cancer cells, without similar affects on non-cancerous CCD-1095Sk fibroblasts and 293 cells, as measured by MTT and colony formation assays. Icaritin treatment caused a rapid increase in ROS in HeLa and SiHa cells, which was followed by a prominent increase in the number of DNA strand breaks. Consequently, the levels of the pro-apoptotic protein Bax and activated caspase 3 and 9 enzymes were increased, while the levels of the anti-apoptotic proteins Bcl-2 and XIAP were downregulated. These protein expression changes were accompanied by marked induction of apoptosis in icaritin-treated cancer cells. The results suggested that the icaritin-induced ROS overload promoted cancer cell death via induction of extensive oxidative DNA damage, which subsequently resulted in large numbers of DNA strand breaks and the activation of the intrinsic apoptotic pathway.

The cardioprotective effect of thymoquinone on ischemia-reperfusion injury in isolated rat heart via regulation of apoptosis and autophagy

Thymoquinone (TQ), as the active constituents of black cumin (Nigella sativa) seed oil, has been reported to have potential protective effects on the cardiovascular system. This study aimed to investigate the effects and the underlying mechanisms of TQ on myocardial ischemia-reperfusion (I/R) injury in Langendorff-perfused rat hearts. Wister rat hearts were subjected to I/R and the experimental group were pretreated with TQ prior to I/R. Hemodynamic parameters, myocardial infarct size, cardiac marker enzymes, superoxide dismutase (SOD), malondialdehyde (MDA) content, and cardiomyocyte apoptosis were assayed. Compared with the untreated group, TQ preconditioning significantly improved cardiac function, reduced infarct size, decreased cardiac lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) levels, suppressed enedoxidative stress, and apoptosis. In addition, TQ treatment promoted autophagy, which was partially reversed by chloroquine (CQ), a kind of autophagy blocker. Our study suggests that TQ can protect heart against I/R injury, which is associated with anti-oxidative and anti-apoptotic effects through activation of autophagy.

Antitumoral action of icaritin in LNCaP prostate cancer cells by regulating PEA3/HER2/AR signaling

Human epidermal growth factor receptor type 2 (HER2) and androgen receptor (AR) are critical factors for prostate cancer (PCa) progression. These factors regulate tumor cell survival and proliferation, and remain as crucial drivers of castration-resistant PCa progression. Icaritin (ICT) is a prenyl flavonoid derived from the Epimedium genus, which has many biological and pharmacological effects. Using androgen-sensitive human prostate carcinoma LNCaP cell lines, we found that 35 μg/ml of ICT could inhibit more than 50% of cell proliferation, induce cell apoptosis, and lead to a strong G1 phase arrest by targeting cyclin-related proteins and suppressing the ability of cell invasion. Moreover, ICT exerts its potent anticancer efficacy by inducing polyomavirus enhancer activator 3 (PEA3) to inhibit the aberrantly activated HER2/AR signaling. In addition, after PEA3 expression was silenced by specific small-interference RNA, we found that both the ICT-inhibited effect on LNCaP cell proliferation and the ICT-induced cell apoptosis rate decreased. These results provide alternative mechanisms for the antitumor actions of ICT, indicating that ICT might be a promising therapeutic agent, as well as a preventive agent, for hormone therapy-resistant PCa.

Icaritin induces MC3T3-E1 subclone14 cell differentiation through estrogen receptor-mediated ERK1/2 and p38 signaling activation

Icaritin (ICT), a hydrolytic product of icariin from the genus Epimedium, has many indicated pharmacological and biological activities. Several studies have shown that ICT has potential osteoprotective effects, including stimulation of osteoblast differentiation and inhibition of osteoclast differentiation. However, the molecular mechanism for this anabolic action of ICT remains largely unknown. Here, we found that ICT could enhance MC3T3-E1 subclone 14 preosteoblastic cell differentiation associated with increased mRNA levels and protein expression of the differentiation markers alkaline phosphatase (ALP), type 1 collagen (COL1), osteocalcin (OC), osteoponin (OPN) and runt-related transcription factor 2 (RUNX2), and improved mineralization, confirmed by bone nodule formation and collagen synthesis. To characterize the underlying mechanisms, we examined the effect of ICT on estrogen receptor (ER) and mitogen-activated protein kinase (MAPK) signaling. ICT treatment induced p38 kinase and extracellular signal-regulated kinase 1/2 (ERK1/2) activation, but it demonstrated at the same time point no effect on activation of c-Jun N-terminal kinase (JNK). ER antagonist ICI182780, p38 antagonist SB203580 and ERK1/2 antagonist PD98059 markedly inhibited the ICT-induced the mRNA expression of ALP, COL1, OC and OPN. ICI182780 attenuated the ICT-induced phosphorylation of p38 and ERK1/2. These observations indicate a potential mechanism of osteogenic effects of ICT involving the ERK1/2 and p38 pathway activation through the ER.

Mitochondrial toxicity of perfluorooctane sulfonate in mouse embryonic stem cell-derived cardiomyocytes

Perfluorooctane sulfonate (PFOS) is a persistent organic contaminant that may cause cardiotoxicity in animals and humans. However, little is known about the underlying mechanism by which it affects the organelle toxicity in cardiomyocytes during the cardiogenesis. Our previous proteomic study showed that differences of protein expression mainly existed in mitochondria of cardiomyocytes differentiated from embryonic stem (ES) cells after exposure to PFOS. Here, we focused on mitochondrial toxicity of PFOS in ES cell-derived cardiomyocytes. The cardiomyogenesis from ES cells in vitro was inhibited, and the expression of L-type Ca²⁺ channel (LTCC) was decreased to interrupt [Ca²⁺]_c transient amplitude in cardiomyocytes after PFOS treatment. Transmission electron microscope revealed that swollen mitochondrion with vacuole in PFOS-treated cells. Meanwhile, mitochondrial transmembrane potential (ΔΨm) was declined and ATP production was lowered. These changes were related to the increased EGFR phosphorylation, activated Rictor signaling, then mediated HK2 binding to mitochondrial membrane. Furthermore, PFOS reduced the interaction of IP3R-Grp75-VDAC and accumulated intracellular fatty acids by activating Rictor, thereby attenuating PGC-1α and Mfn2 expressions, then destroying mitochondria-associated endoplasmic reticulum membrane (MAM), which resulted in the decrease of [Ca²⁺]_mito transient amplitude triggered by ATP. In conclusion, mitochondrial structure damages and abnormal Ca²⁺ shuttle were the important aspects in PFOS-induced cardiomyocytes toxicity from ES cells by activating Rictor signaling pathway.

Arsenic Trioxide and Icariin Show Synergistic Anti-leukemic Activity

Although As2O3 (ATO) has been recommended as the front-line agent for treatment of acute promyelocytic leukemia (APL), particularly for relapsed or refractory APL, it has been associated with profound toxicity. Icariin is a natural compound with activity against a variety of cancers. This study was designed to investigate the effect of Icariin on APL cells and to determine whether Icariin can potentiate the antitumor activity of ATO in APL cells. Cell proliferation and apoptosis were measured using MTT assay and flow cytometry, respectively. The expression of apoptosis and proliferation-related molecules was detected by Western blotting. Reactive oxygen species (ROS) and mitochondrial membrane potential were determined with florescence staining. Icariin inhibited proliferation in a dose-dependent manner and induced apoptosis in both of the tested APL cell lines. Icariin enhanced the in vitro antitumor activity of ATO against APL. The antitumor activity of Icariin and its enhancement of the antitumor activity of ATO correlated with the increase in accumulation of intracellular ROS. Our results showed that Icariin, by increasing intracellular ROS, exhibited antitumor activity and potentiated the antitumor activity of ATO against APL. Therefore, combination treatment with Icariin and ATO might offer a novel therapeutic option for patients with APL, although further studies are needed.

Icaritin enhances mESC self-renewal through upregulating core pluripotency transcription factors mediated by ERα

Utilization of small molecules in modulation of stem cell self-renewal is a promising approach to expand stem cells for regenerative therapy. Here, we identify Icaritin, a phytoestrogen molecule enhances self-renewal of mouse embryonic stem cells (mESCs). Icaritin increases mESCs proliferation while maintains their self-renewal capacity in vitro and pluripotency in vivo. This coincides with upregulation of key pluripotency transcription factors OCT4, NANOG, KLF4 and SOX2. The enhancement of mESCs self-renewal is characterized by increased population in S-phase of cell cycle, elevation of Cylin E and Cyclin-dependent kinase 2 (CDK2) and downregulation of p21, p27 and p57. PCR array screening reveals that caudal-related homeobox 2 (Cdx2) and Rbl2/p130 are remarkably suppressed in mESCs treated with Icaritin. siRNA knockdown of Cdx2 or Rbl2/p130 upregulates the expression of Cyclin E, OCT4 and SOX2, and subsequently increases cell proliferation and colony forming efficiency of mESCs. We then demonstrate that Icaritin co-localizes with estrogen receptor alpha (ERα) and activates its nuclear translocation in mESCs. The promotive effect of Icaritin on cell cycle and pluripotency regulators are eliminated by siRNA knockdown of ERα in mESCs. The results suggest that Icaritin enhances mESCs self-renewal by regulating cell cycle machinery and core pluripotency transcription factors mediated by ERα.

Involvement of Rictor/mTORC2 in cardiomyocyte differentiation of mouse embryonic stem cells in vitro

Rictor is a key regulatory/structural subunit of the mammalian target of rapamycin complex 2 (mTORC2) and is required for phosphorylation of Akt at serine 473. It plays an important role in cell survival, actin cytoskeleton organization and other processes in embryogenesis. However, the role of Rictor/mTORC2 in the embryonic cardiac differentiation has been uncovered. In the present study, we examined a possible link between Rictor expression and cardiomyocyte differentiation of the mouse embryonic stem (mES) cells. Knockdown of Rictor by shRNA significantly reduced the phosphorylation of Akt at serine 473 followed by a decrease in cardiomyocyte differentiation detected by beating embryoid bodies. The protein levels of brachyury (mesoderm protein), Nkx2.5 (cardiac progenitor cell protein) and α-Actinin (cardiomyocyte biomarker) decreased in Rictor knockdown group during cardiogenesis. Furthermore, knockdown of Rictor specifically inhibited the ventricular-like cells differentiation of mES cells with reduced level of ventricular-specific protein, MLC-2v. Meanwhile, patch-clamp analysis revealed that shRNA-Rictor significantly increased the number of cardiomyocytes with abnormal electrophysiology. In addition, the expressions and distribution patterns of cell-cell junction proteins (Cx43/Desmoplakin/N-cadherin) were also affected in shRNA-Rictor cardiomyocytes. Taken together, the results demonstrated that Rictor/mTORC2 might play an important role in the cardiomyocyte differentiation of mES cells. Knockdown of Rictor resulted in inhibiting ventricular-like myocytes differentiation and induced arrhythmias symptom, which was accompanied by interfering the expression and distribution patterns of cell-cell junction proteins. Rictor/mTORC2 might become a new target for regulating cardiomyocyte differentiation and a useful reference for application of the induced pluripotent stem cells.

Icaritin Reduces Oral Squamous Cell Carcinoma Progression via the Inhibition of STAT3 Signaling

Icaritin, a traditional Chinese medicine, possesses antitumor activity. The current study aimed to investigate icaritin effect and potential mechanism on oral squamous cell carcinoma (OSCC) development. OSCC cells proliferation, apoptosis, and autophagy were analyzed after incubation with icaritin at different concentrations and incubation times. The expressions of proteins related to proliferation, apoptosis, and autophagy, as well as signal transducer and activator of transcription 3 (STAT3) signal network, were also evaluated by western blot. Furthermore, STAT3 was knocked down by siRNA transfection to determine STAT3 role in OSCC cell proliferation and apoptosis. An oral specific carcinogenesis mouse model was used to explore icaritin effect on OSCC in vivo. Icaritin significantly inhibited OSCC proliferation in vitro and reduced the expression of both the cell-cycle progression proteins cyclin A2 and cyclin D1. Besides, icaritin increased cleaved caspase 3 and cleaved poly-(ADP-ribose) polymerase expression leading to apoptosis, and it activated autophagy. Icaritin significantly inhibited the expression of phospho-STAT3 (p-STAT3) in a dose- and time-dependent manner. In the in vivo experiment, the number of malignant tumors in the icaritin-treated group was significantly lower than the control. Overall, icaritin suppressed proliferation, promoted apoptosis and autophagy, and inhibited STAT3 signaling in OSCC in vitro and in vivo. In conclusion, icaritin might be a potential therapeutic agent against OSCC development.

Anhydroicaritin improves diet-induced obesity and hyperlipidemia and alleviates insulin resistance by suppressing SREBPs activation

SREBPs play important roles in the regulation of lipid metabolism, and are closely related to the occurrence and development of many metabolic diseases. Small molecular inhibitors of SERBPs are important tools in developing efficient treatment of metabolic diseases. However, there are no listing drug targeting SREBPs. Therefore, there is an urgent need to develop highly specific small molecules that inhibit SREBPs. In this study, using a hepatocyte-based high-throughput screening, we identified anhydroicaritin (AHI) as a novel inhibitor of SREBPs. HepG2, HL-7702, and human primary hepatocytes were used to verify the effects of AHI. We explored the mechanism by which AHI blocks the binding of SCAP/SREBPs complex with Sec23α/24D via regulating LKB1/AMPK/mTOR pathway. AHI reduced liver cell lipid level by preventing de novo lipogenesis. In diet induced obese mice, AHI ameliorated obesity, insulin resistance, fatty accumulation in liver and hyperlipemia. In conclusion, AHI improves diet-induced obesity and alleviates insulin resistance by suppressing SREBPs maturation which is dependent on LKB1/AMPK/mTOR pathway. Thus, AHI can serve as a leading compound for pharmacological control of metabolic diseases.

A novel anti-cancer agent Icaritin suppresses hepatocellular carcinoma initiation and malignant growth through the IL-6/Jak2/Stat3 pathway

Tumor-initiating cell (TIC) is a subpopulation of cells in tumors that are responsible for tumor initiation and progression. Recent studies indicate that hepatocellular carcinoma-initiating cells (HCICs) confer the high malignancy, recurrence and multi-drug resistance in hepatocellular carcinoma (HCC). In this study, we found that Icaritin, a prenylflavonoid derivative from Epimedium Genus, inhibited malignant growth of HCICs. Icaritin decreased the proportion of EpCAM-positive (a HCICs marker) cells, suppressed tumorsphere formation in vitro and tumor formation in vivo. We also found that Icaritin reduced expression of Interleukin-6 Receptors (IL-6Rs), attenuated both constitutive and IL-6-induced phosphorylation of Janus-activated kinases 2 (Jak2) and Signal transducer and activator of transcription 3 (Stat3), and inhibited Stat3 downstream genes, such as Bmi-1 and Oct4. The inhibitory activity of Icaritin in HCICs was augmented by siRNA-mediated silencing of Stat3 but attenuated by constitutive activation of Stat3. Taken together, our results indicate that Icaritin is able to inhibit malignant growth of HCICs and suggest that Icaritin may be developed into a novel therapeutic agent for effective treatment of HCC.

A novel anticancer agent icaritin inhibited proinflammatory cytokines in TRAMP mice

PURPOSE

We aimed to investigate whether icaritin (ICT) would inhibit serum proinflammatory cytokines and postpone prostate cancer (PCa) development and progression in both normal diet and high-fat diet (HFD) transgenic adenocarcinoma mouse prostate (TRAMP) mice.

METHODS

TRAMP mice were randomly divided into four groups: normal diet with/without ICT group and HFD with/without ICT group. Each TRAMP mouse received intraperitoneal injection of ICT solution at the dose of 30 mg/kg 5 times per week.

RESULTS

ICT treatment could significantly increase the survival when compared with those in normal diet group (P = 0.015, log-rank test) and HFD group (P = 0.009, log-rank test). Proinflammatory cytokine levels, including IL-1α, IL-1β, IL-6, and TNF-α, were decreased more or less in ICT-treated TRAMP mice. Moreover, significant higher inflammation scores were detected in normal diet group and HFD group compared with their relevant ICT treatment groups (P = 0.026 and P = 0.006, respectively). Meanwhile, the incidences of well-differentiated tumor tissue in two ICT treatment groups (39.13 and 31.82 %) were moderately higher than control groups (29.41 and 20.00 %, respectively), though no significant difference was observed.

CONCLUSIONS

Taken together, our findings indicate that ICT could inhibit the development and progression of PCa in TRAMP mice via inhibiting proinflammatory cytokines.

Protein profiles of cardiomyocyte differentiation in murine embryonic stem cells exposed to perfluorooctane sulfonate

Perfluorooctane sulfonate (PFOS) is a persistent organic contaminant that may affect diverse systems in animals and humans, including the cardiovascular system. However, little is known about the mechanism by which it affects the biological systems. Herein, we used embryonic stem cell test procedure as a tool to assess the developmental cardiotoxicity of PFOS. The differentially expressed proteins were identified by quantitative proteomics that combines the stable isotope labeling of amino acids with high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. Results of the embryonic stem cell test procedure suggested that PFOS was a weak embryotoxic chemical. Nevertheless, a few marker proteins related to cardiovascular development (Brachyury, GATA4, MEF2C, α-actinin) were significantly reduced by exposure to PFOS. In total, 176 differential proteins were identified by proteomics analysis, of which 67 were upregulated and 109 were downregulated. Gene ontology annotation classified these proteins into 13 groups by molecular functions, 12 groups by cellular locations and 10 groups by biological processes. Most proteins were mainly relevant to either catalytic activity (25.6%), nucleus localization (28.9%) or to cellular component organization (19.8%). Pathway analysis revealed that 32 signaling pathways were affected, particularly these involved in metabolism. Changes in five proteins, including L-threonine dehydrogenase, X-ray repair cross-complementing 5, superoxide dismutase 2, and DNA methyltransferase 3b and 3a were confirmed by Western blotting, suggesting the reliability of the technique. These results revealed potential new targets of PFOS on the developmental cardiovascular system.

Icaritin suppresses multiple myeloma, by inhibiting IL-6/JAK2/STAT3

Icaritin is an active prenylflavonoid derived from Epimedium genus, a traditional Chinese medicine. Icaritin has a wide range of pharmacological and biological activities, including cardiovascular function improvement, hormone regulation and antitumor activity. Here, we investigated the effect of icaritin on multiple myeloma (MM) in vitro and in vivo. Icaritin inhibited cell growth of MM cell line and primary MM cells. In contrast, icaritin had low or no cytotoxic effect on normal hematopoiesis. We also demonstrated that in MM xenograft mouse models, icaritin suppressed tumor growth and decreased serum IL-6 and IgE levels, but did not show adverse reactions such as body weight loss. The anti-MM activity of icaritin was mainly mediated by inhibiting IL-6/JAK2/STAT3 signaling. We suggest that icaritin can be further tested in clinical trials in MM.

The Cardioprotective Effect of Icariin on Ischemia-Reperfusion Injury in Isolated Rat Heart: Potential Involvement of the PI3K-Akt Signaling Pathway

AIMS

Icariin (ICA), a flavonoid isolated from epimedii, has been reported to have potential protective effects on the cardiovascular system. This study is to investigate the effect and the underlying mechanisms of ICA on ischemia/reperfusion (I/R) injury.

METHODS

Wister rat hearts were subjected to I/R using Langendorff perfusion system. Cardiac function, myocardial infarct size, lactate dehydrogenase (LDH), and creatine kinase-MB (CK-MB) activities in coronary effluent, and superoxide dismutase (SOD) and malondialdehyde (MDA) content in heart tissue and cardiomyocyte apoptosis were assayed.

RESULTS

Compared with the I/R group, ICA treatment significantly improved cardiac function, decreased myocardial infarct size, enzyme activity, oxidative stress, and apoptosis. In addition, ICA treatment lead to an increased p-Akt level, which was partially reversed by LY294002, a PI3K pathway inhibitor.

CONCLUSION

Our study suggests that ICA has a cardioprotective effect against I/R injury, which is associated with its antioxidative and anti-apoptotic effect, at least partially, through the activation of PI3K-Akt signaling pathway.

Icaritin acts synergistically with epirubicin to suppress bladder cancer growth through inhibition of autophagy

Bladder cancer is one of the most commonly diagnosed urological malignancies. Acquired resistance to chemotherapy is a great barrier for achieving successful treatment of bladder cancer. In the present study, we investigated the effect and mechanisms of icaritin, a flavonol glycoside derived from genus Epimedium, against human bladder cancer cells. It was found that despite the low cytotoxicity in normal human HEK293 cells, icaritin significantly inhibited the proliferation and colony formation of BT5637 and T24 bladder cancer cells time- and dose-dependently compared to the DMSO vehicle control. Moreover, cell viability monitored through mitochondrial membrane potential was inhibited markedly after icaritin treatment. Further investigation indicated that icaritin may inhibit epirubicin (EPI)-induced autophagy, and acted synergistically with EPI to suppress the proliferation of BT5637 and T24 cells. These findings suggest that icaritin may prove to be a novel potent therapeutic agent for the treatment of bladder cancer.

Icaritin Attenuates Myocardial Ischemia and Reperfusion Injury Via Anti-Inflammatory and Anti-Oxidative Stress Effects in Rats

Icaritin (ICT) is a traditional Chinese medicinal herb proved to be neuroprotective and exerts promoting effects on cardiac differentiation. However, its role in cardioprotection against myocardial ischemia/reperfusion (MI/R) injury remains largely unknown. This study aimed to investigate the effects of ICT treatment on MI/R injury and the underlying mechanisms. Rats were subjected to 30 min of myocardial ischemic insult followed by 3 h of reperfusion. ICT (3, 10, and 30 mg/kg) was administered intraperitoneally 10 min before reperfusion. ICT treatment at the dose of 10 and 30 mg/kg improved cardiac function and limited infarct size following MI/R. Meanwhile, ICT reduced plasma creatine kinase (CK), lactate dehydrogenase (LDH) activities and cardiomyocyte apoptosis in I/R heart tissue. Moreover, ICT treatment not only inhibited the pro-inflammatory cytokine TNF-α production and increased the anti-inflammatory cytokine IL-10 level in myocardium but also reduced the increase in the generation of superoxide content and malondialdehyde (MDA) formation and simultaneously increased the anti-oxidant capability in I/R hearts. Furthermore, ICT treatment increased Akt phosphorylation and inhibited PTEN expression in I/R hearts. PI3K inhibitor wortmannin inhibited ICT-enhanced Akt phosphorylation, and blunted ICT-mediated anti-oxidative and anti-inflammatory effects and cardioprotection. Our study indicated for the first time that ICT reduces inflammation and oxidative stress and protects against MI/R injury in rats, which might be via a PI3K–Akt-dependent mechanism.

Pharmacological effects and pharmacokinetic properties of icariin, the major bioactive component in Herba Epimedii

Herba Epimedii is an important medicinal plant which has been used in various traditional Chinese formulations for thousands of years as well as in modern proprietary traditional Chinese medicine products. It has extensive clinical indications, especially for the treatment of sexual dysfunction and osteoporosis. There have been more than 260 chemical moieties identified in the genus Epimedium most of which belong to flavonoids. Icariin is the most abundant constituent in Herba Epimedii. Icariin is pharmacologically bioactive and demonstrates extensive therapeutic capacities such as osteoprotective effect, neuroprotective effect, cardiovascular protective effect, anti-cancer effect, anti-inflammation effect, immunoprotective effect and reproductive function. Particularly, the significant osteogenic effect of icariin made it a promising drug candidate in bone tissue engineering. The current review paper aims to summarize the literatures reporting the pharmacological effects of icariin. The pharmacokinetic properties of bioactive ingredients in Herba Epimedii have also been discussed.

Anticancer agent icaritin induces apoptosis through caspase-dependent pathways in human hepatocellular carcinoma cells

Icaritin is an active ingredient derived from the plant Herba epimedium, which exhibits various pharmacological and biological activities. However, the function, and the underlying mechanisms of icaritin on the growth of SMMC‑7721 human hepatoma cells have yet to be elucidated. The present study aimed to investigate the function and underlying mechanisms of icaritin in the growth of SMMC‑7721 cells. The cells were treated with varying concentrations of icaritin for 12, 24 and 48 h, respectively, prior to cytotoxic analysis. Apoptosis of SMMC‑7721 cells following treatment with icaritin was measured using flow cytometry. The gene expression of mitochondria‑ and Fas‑mediated caspase‑dependent pathways was detected by reverse transcription‑quantitative polymerase chain reaction and western blotting. Statistical analysis was performed by Student's t‑test and one‑way analysis or variance. The present study demonstrated that treatment with icaritin significantly inhibited growth, and induced apoptosis of SMMC‑7721 cells, in a time‑ and dose‑dependent manner. In addition, icaritin triggered the mitochondrial/caspase apoptotic pathway, by decreasing the Bcl‑2/Bax protein ratio and increasing activation of caspase‑3. Icaritin also activated the Fas‑mediated apoptosis pathway, as was evident by the increased expression levels of Fas and activation of caspase‑8. These data suggest that icaritin may be a potent growth inhibitor and induce apoptosis of SMMC‑7721 cells through the mitochondria‑ and Fas‑mediated caspase‑dependent pathways. The present study may provide experimental evidence for preclinical and clinical evaluations of icaritin for HCC therapy.

Biodistribution evaluation of icaritin in rats by ultra-performance liquid chromatography-tandem mass spectrometry

ETHNOPHARMACOLOGICAL RELEVANCE

Icaritin (ICT) is a major bioactive prenylflavonoid derivative contained in the Epimedium which is a widely used herbal medicine for the treatment of infertility, impotence, cardiovascular and skeletal diseases listed in the Chinese Pharmacopoeia. The aim of this study is to investigate the tissue distribution of ICT in rats by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) MATERIALS AND METHODS: ICT was intraperitoneally administrated to rats for 7 consecutive days at dose levels of 20, 40 and 60 mg/kg/day, respectively. Various tissue homogenates were pretreated by protein precipitation with acetonitrile. ICT and internal standard coumestrol were separated on a BEH C18 column with a gradient mobile phase and detected using precursor-product ion transitions of m/z 367.1→297.1 for ICT and 267.0→211.1 for coumestrol at the negative ionization mode, respectively.

RESULTS

ICT was widely distributed in rat's various tissues and its concentrations in tissues increased with elevated doses. A sensitive and reliable UPLC-MS/MS method was firstly established to quantify ICT in rat tissues. The lower limit of quantification was 0.5 ng/mL based on 100 μL of tissue homogenates. The intra- and inter-day accuracy at all levels fell in the ranges of 90.8-103.4% and 91.6-100.3%, and the intra- and inter-day precision (RSD) were in the ranges of 2.9-10.5% and 2.6-9.1%, respectively.

CONCLUSIONS

The UPLC-MS/MS showed good accuracy, precision and recovery and was suitable for the quantification of ICT in rat tissues. Wide distribution of ICT could helpfully elucidate systemic effects and various functions of ICT.

Icaritin suppresses the proliferation of human osteosarcoma cells in vitro by increasing apoptosis and decreasing MMP expression

AIM

To explore whether icaritin, a prenylflavonoid derivative of the Chinese tonic herb Epimedium, could suppress the proliferation of human osteosarcoma cells in vitro, and to elucidate the mechanisms of the action.

METHODS

Human osteosarcoma SaOS2 cell line was used in the present study. The proliferation of the cells was examined using MTT assay and immunofluorescence DAPI staining. Cell motility was studied with the scratch assay. Cell apoptosis was determined by Annexin V-FITC and PI double staining using flow cytometry. Western blotting and RT-PCR were used to measure the expression of mRNAs and proteins in the cells.

RESULTS

Icaritin (5-15 μmol/L) suppressed the proliferation of SaOS2 cells in vitro in a dose-dependent manner. Furthermore, the cell motility was significantly decreased after exposure to icaritin. Moreover, icaritin (5 μmol/L) time-dependently induced the apoptosis of SaOS2 cells, markedly suppressed MMP-2 and MMP-9 expression, upregulated caspase-3 and caspase-9 expression, and increased the level of cleaved caspase-3 in the cells. Co-exposure to the caspase-3 inhibitor zVAD-fmk (10 μmol/L) compromised the icaritin-induced caspase-3 expression and apoptosis in SaOS2 cells.

CONCLUSION

Icaritin suppresses the proliferation of SaOS2 human osteosarcoma cells by increasing apoptosis and downregulating MMP expression.

Icaritin inhibits JAK/STAT3 signaling and growth of renal cell carcinoma

Signal transducer and activator of transcription-3 (STAT3) is critical for cancer progression by regulating tumor cell survival, proliferation, and angiogenesis. Herein, we investigated the regulation of STAT3 activation and the therapeutic effects of Icaritin, a prenyl flavonoid derivative from Epimedium Genus, in renal cell carcinoma (RCC). Icaritin showed significant anti-tumor activity in the human and mouse RCC cell lines, 786-O and Renca, respectively. Icaritin inhibited both constitutive and IL-6-induced phospho-STAT3 (STAT3(Y705)) and reduced the level of STAT3-regulated proteins Bcl-xL, Mcl-1, Survivin, and CyclinD1 in a dose-dependent manner. Icaritin also inhibited activation of Janus-activated kinase-2 (JAK2), while it showed minimal effects on the activation of other key signaling pathways, including AKT and MAPK. Expression of the constitutively active form of STAT3 blocked Icaritin-induced apoptosis, while siRNA directed against STAT3 potentiated apoptosis. Finally, Icaritin significantly blunted RCC tumor growth in vivo, reduced STAT3 activation, and inhibited Bcl-xL and Cyclin E, as well as VEGF expression in tumors, which was associated with reduced tumor angiogenesis. Overall, these results suggest that Icaritin strongly inhibits STAT3 activation and is a potentially effective therapeutic option for the treatment of renal cell carcinoma.

Icaritin reverses multidrug resistance of HepG2/ADR human hepatoma cells via downregulation of MDR1 and P‑glycoprotein expression

Multidrug resistance (MDR) of tumor cells is a serious obstacle encountered in cancer treatment. In the current study a multiple drug‑resistant HepG2/adriamycin (HepG2/ADR) cell line was established and its MDR was characterized. Icaritin, an active ingredient isolated from the medical plant Herba Epimedium, was observed to reverse MDR in the present model. Icaritin significantly increased the intracellular accumulation of ADR and decreased the expression of the MDR1 gene in HepG2/ADR cells compared with drug‑sensitive HepG2 cells. In addition, the present results showed that icaritin may significantly downregulate the expression of P‑glycoprotein. These results indicate that icaritin is a novel and potent MDR reversal agent and may be a promising drug for tumor chemotherapy.

Icaritin synergistically enhances the radiosensitivity of 4T1 breast cancer cells

Icaritin (ICT) is a hydrolytic form of icariin isolated from plants of the genus Epimedium. This study was to investigate the radiosensitization effect of icaritin and its possible underlying mechanism using murine 4T1 breast cancer cells. The combination of Icaritin at 3 µM or 6 µM with 6 or 8 Gy of ionizing radiation (IR) in the clonogenic assay yielded an ER (enhancement ratio) of 1.18 or 1.28, CI (combination index) of 0.38 or 0.19 and DRI (dose reducing index) of 2.51 or 5.07, respectively. These strongly suggest that Icaritin exerted a synergistic killing (?) effect with radiation on the tumor cells. This effect might relate with bioactivities of ICT: 1) exert an anti-proliferative effect in a dose- and time-dependent manner, which is different from IR killing effect but likely work together with the IR effect; 2) suppress the IR-induced activation of two survival paths, ERK1/2 and AKT; 3) induce the G2/M blockage, enhancing IR killing effect; and 4) synergize with IR to enhance cell apoptosis. In addition, ICT suppressed angiogenesis in chick embryo chorioallantoic membrane (CAM) assay. Taken together, ICT is a new radiosensitizer and can enhance anti-cancer effect of IR or other therapies.

Phytoestrogenic molecule desmethylicaritin suppressed adipogenesis via Wnt/β-catenin signaling pathway

Epimedium flavonoids inhibit extravascular lipid deposition during prevention of steroid-associated osteonecrosis. Desmethylicaritin is a bioactive metabolite of Epimedium flavonoids in serum. As it is well known that estrogen inhibits aidpogenesis, so we hypothesized that desmethylicaritin as a phytoestrogen might have the potential to inhibit lipid deposition. This study was designed to investigate the effect of desmethylicaritin on adipogenesis and its underlying mechanism in vitro. Adipogenesis was assessed by Oil Red O staining in 3T3-L1 preadipocytes. Bromodeoxyuridine was used to test the clonal expansion. Further, the mRNA level and protein expression of adipgenic and related factors were detected by qRT-PCR and western blot, respectively. The nuclear location of β-catenin was identified using immunofluoresence assay. Our results showed that desmethylicaritin suppressed the adipogenesis in 3T3-L1 cells in a dose-dependent manner. In addition, desmethylicaritin inhibited clonal expansion during adipogenesis. Desmethylicaritin did not affect CCAAT/enhancer binding protein δ and β mRNA expression, but decreased the mRNA expression of CCAAT/enhancer binding protein α, peroxisome proliferator-activated receptor γ, adipocyte lipid-binding protein and lipoprotein lipase. Desmethylicaritin up-regulated the mRNA expression of Wnt10b that was however down-regulated after adipogenic induction. Desmethylicaritin increased the protein expression of β-catenin both in the cytoplasm and nuclei and immunofluorescence results confirmed that desmethylicaritin increased nuclear translocation of β-catenin. Above findings implied that desmethylicaritin was able to inhibit adipogenesis and Wnt/β-catenin signaling pathway was regulated by desmethylicaritin in the process of suppression of adipogenesis. Above findings supported desmethylicaritin as a novel phytochemical agent for potential prevention of disorders involving lipid metabolism.

Activating glucocorticoid receptor-ERK signaling pathway contributes to ginsenoside Rg1 protection against β-amyloid peptide-induced human endothelial cells apoptosis

The deposition of β-amyloid (Aβ) in neurons and vascular cells of the brain has been characterized in Alzheimer's disease. Ginsenoside Rg1 (Rg1) is an active components in Panax ginseng, a famous traditional Chinese medicines recorded in Compendium of Materia Medica. Present study attempted to evaluate the potential mechanisms of Aβ-mediated insult and the protective effects of Rg1 on human endothelial cells. Rg1 attenuated the Aβ25-35-associated mitochondrial apoptotic events, accompanied by inhibiting HIF-1α expression followed by intracellular reactive nitrogen species generation, and protein nitrotyrosination. These protective effects were abolished by glucocorticoid receptor (GR) antagonist RU486 or p-ERK inhibitor U0126 rather than estrogen receptor α antagonist ICI 82,780. Taken together, our results suggested that Rg1 protected against Aβ25-35-induced apoptosis at least in part by two complementary GR-dependent ERK phosphorylation pathways: (1) down-regulating HIF-1α initiated protein nitrotyrosination, and (2) inhibiting mitochondrial apoptotic cascades. These data provided a novel insight to the mechanisms of Rg1protective effects on Aβ25-35-induced endothelial cells apoptosis, suggesting that GR-ERK signaling pathway might play an important role in it.

mGluR5 stimulating Homer-PIKE formation initiates icariin induced cardiomyogenesis of mouse embryonic stem cells by activating reactive oxygen species

Icariin (ICA) has been reported to facilitate cardiac differentiation of mouse embryonic stem (ES) cells; however, the mechanism by which ICA induced cardiomyogenesis has not been fully elucidated yet. Here, an underlying signaling network including metabotropic glutamate receptor 5 (mGluR5), Homer, phosphatidylinositol 3-Kinase Enhancer (PIKE), phosphatidylinositol 3-Kinase (PI3K), reactive oxygen species (ROS) and nuclear factor-kappaB (NF-κB) was investigated in ICA induced cardiomyogenesis. Our results showed that the co-expression of mGluR5 together with α-actinin or Troponin T in embryoid bodies (EBs) treated with ICA was elevated to 10.86% and 9.62%, compared with the case in the control (4.04% and 3.45%, respectively). Exposure of EBs to ICA for 2 h remarkably increased the dimeric form of mGluR5, which was inhibited by small interfering RNA targeting mGluR5 (si-mGluR5). Moreover, the extracellular glutamate concentration in ICA treatment medium was elevated to 28.9±3.5 μM. Furthermore, the activation of mGluR5 by ICA triggered the formation of Homer-PIKE complex and activated PI3K, stimulating ROS generation and NF-κB nuclear translocation. Knockdown of mGluR5 or inhibition of PI3K by LY294002 blocked ICA induced cardiomyogenesis via repressing mGluR5 pathway, reducing ROS and NF-κB activation. These results revealed that the inducible mechanisms of ICA were related to activate mGluR5 pathway.

The expression of calcium-sensing receptor in mouse embryonic stem cells (mESCs) and its influence on differentiation of mESC into cardiomyocytes

The calcium-sensing receptor (CaSR), a G protein coupled receptor, is involved in a number of physiological and pathological processes. Embryonic stem cells (ESCs) have a potential role to differentiate into all types of cells. Whether CaSR is functionally expressed in ESCs is unclear. In this study, the expression and distribution of CaSR in 129 mouse ES-D3 cell lines were detected by Western blotting and immunofluorescence; and the intracellular calcium concentration ([Ca(2+)]i) was measured using Laser Confocal Scanning Microscopy. Mouse embryonic stem cells (mESCs) were cultured to embryoid bodies (EBs) and the differentiation of EBs into cardiomyocytes was induced by icariin (ICA). The cardiac specific proteins, a-Actinin and cardiac troponin-I (cTnI), were analyzed by immunofluorescence, and the differentiation rate was analyzed by flow cytometry. The expression of cardiac-specific transcription factors, Nkx2.5 and GATA-4, was detected by Western blotting. We found that the CaSR protein exists in both mESCs and mESC-derived cardiomyocytes (mESC-CMs). Increasing extracellular calcium or neomycin (an agonist of CaSR) increased [Ca(2+)]i and the differentiation rate. These effects were abolished by inhibition of CaSR, phospholipase C, IP3 receptor and Ca(2+) ATPase, or by depletion of the sarcoplasmic reticulum Ca(2+) store, respectively. Activation of CaSR up-regulated protein expression of Nkx2.5 and GATA4 in EBs at an early stage of ICA-induced differentiation. In conclusion, CaSR is functionally expressed in mESCs, and activation of CaSR is involved in the differentiation of mESCs into cardiomyocytes by facilitating the expression of NKx2.5 and GATA-4.