Lanatoside C protects mice against bleomycin-induced pulmonary fibrosis through suppression of fibroblast proliferation and differentiation.

It has been established that lanatoside C, a FDA-approved cardiac glycoside, reduces proliferation of cancer cell lines. The proliferation of fibroblasts is critical to the pathogenesis of pulmonary fibrosis (PF), a progressive and fatal fibrotic lung disease lacking effective treatment. In this study we have investigated the impact of lanatoside C on a bleomycin (BLM)-induced mouse model of PF and through the evaluation of fibroblast proliferation and activation in vitro. We evaluated explanted lung tissue by histological staining, western blot analysis, qRT-PCR and survival analysis, demonstrating that lanatoside C was able to protect mice against BLM-induced pulmonary fibrosis. The proliferation of cultured pulmonary fibroblasts isolated from BLM-induced PF mice was suppressed by lanatoside C, as hypothesized, through the induction of cell apoptosis and cell cycle arrest at the G2/M phase. The Akt signalling pathway was involved in this process. Interestingly, the production of α-SMA, fibronectin, and collagen I and III in response to TGF-ß1 in healthy mouse fibroblasts was suppressed following lanatoside C administration by inhibition of TGF-ß1/Smad signalling. In addition, TGF-ß1-induced migration in lung fibroblasts was also impeded after lanatoside C treatment. Together, our data revealed that lanatoside C alleviated BLM-induced pulmonary fibrosis in mice via attenuation of growth and differentiation of fibroblasts, suggesting that it has potential as a candidate therapy for PF patients.

Systemic anticancer neural stem cells in combination with a cardiac glycoside for glioblastoma therapy.

The tumor-tropic properties of neural stem cells (NSCs) have been shown to serve as a novel strategy to deliver therapeutic genes to tumors. Recently, we have reported that the cardiac glycoside lanatoside C (Lan C) sensitizes glioma cells to the anticancer agent tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Here, we engineered an FDA-approved human NSC line to synthesize and secrete TRAIL and the Gaussia luciferase (Gluc) blood reporter. We showed that upon systemic injection, these cells selectively migrate toward tumors in the mice brain across the blood-brain barrier, target invasive glioma stem-like cells, and induce tumor regression when combined with Lan C. Gluc blood assay revealed that 30% of NSCs survived 1 day postsystemic injection and around 0.5% of these cells remained viable after 5 weeks in glioma-bearing mice. This study demonstrates the potential of systemic injection of NSCs to deliver anticancer agents, such as TRAIL, which yields glioma regression when combined with Lan C.

Suppression of ER-stress induction of GRP78 as an anti-neoplastic mechanism of the cardiac glycoside Lanatoside C in pancreatic cancer: Lanatoside C suppresses GRP78 stress induction.

The 78 kilodalton glucose-regulated protein (GRP78) is a major endoplasmic reticulum (ER) molecular chaperone with antiapoptotic properties and a key regulator of the unfolded protein response (UPR). ER-stress induction of GRP78 in cancer cells represents a major pro-survival branch of the UPR. Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal disease and high level of GRP78 is associated with aggressive disease and poor survival. Recently, we reported that PDAC exhibited high level of ER stress and that GRP78 haploinsufficiency is sufficient to suppress pancreatic tumorigenesis in mice, suggesting the utility of inhibitors of GRP78 expression in combating pancreatic cancer. Screening of clinically relevant compound libraries revealed that cardiac glycosides (CGs) can inhibit ER-stress induction of GRP78 in pancreatic and other types of human cancers. Using the FDA-approved CG compound Lanatoside C (LanC) and human pancreatic cancer cell lines as model systems, we discovered that LanC preferably suppressed ER stress induction of GRP78 and to a lesser extent GRP94. The suppression is at the post-transcriptional level and dependent on the Na+/K+-ATPase ion pump. Overexpression of GRP78 mitigates apoptotic activities of LanC in ER stressed cells. Our study revealed a new function of CGs as inhibitor of stress induction of GRP78, and that this suppression at least in part contributes to the apoptotic activities of CGs in human pancreatic cancer cells in vitro. These findings support further investigation into CGs as potential antineoplastic agents for pancreatic and other cancers which depend on GRP78 for growth and survival.

Combination of 131I-trastuzumab and lanatoside C enhanced therapeutic efficacy in HER2 positive tumor model.

Lanatoside C has a promising anti-tumor activity and is a potential candidate for radiosensitizers. In this study, we have investigated the therapeutic efficacy of the combination of 131I-trastuzumab and lanatoside C for inhibition of human epidermal growth factor receptor 2 (HER2) positive tumor progression in NCI-N87 xenograft model. The combination treatment (131I-trastuzumab and lanatoside C) showed highest cytotoxicity when compared to non-treated control or trastuzumab alone or 131I alone or 131I-trastuzumab alone in vitro. Biodistribution studies using 131I-trastuzumab or combination of 131I-trastuzumab and lanatoside C showed tumor uptake in BALB/c nude mice bearing HER2 positive NCI-N87 tumor xenograft model. The higher tumor uptake was observed in 131I-trastuzumab (19.40 ± 0.04% ID/g) than in the combination of 131I-trastuzumab and lanatoside C (14.02 ± 0.02% ID/g) at 24 h post-injection. Most importantly, an antitumor effect was observed in mice that received the combination of 131I-trastuzumab and lanatoside C (p = 0.009) when compared to control. In addition, mice received lanatoside C alone (p = 0.085) or 131I-trastuzumab alone (p = 0.160) did not significantly inhibit tumor progression compared with control. Taken together, our data suggest that combination of 131I-trastuzumab and lanatoside C might be a potential synergistic treatment for radioimmunotherapy to control the HER2 positive tumor.

Cardiac glycosides target barrier inflammation of the vasculature, meninges and choroid plexus.

Neuroinflammation is a key component of virtually all neurodegenerative diseases, preceding neuronal loss and associating directly with cognitive impairment. Neuroinflammatory signals can originate and be amplified at barrier tissues such as brain vasculature, surrounding meninges and the choroid plexus. We designed a high content screening system to target inflammation in human brain-derived cells of the blood-brain barrier (pericytes and endothelial cells) to identify inflammatory modifiers. Screening an FDA-approved drug library we identify digoxin and lanatoside C, members of the cardiac glycoside family, as inflammatory-modulating drugs that work in blood-brain barrier cells. An ex vivo assay of leptomeningeal and choroid plexus explants confirm that these drugs maintain their function in 3D cultures of brain border tissues. These results suggest that cardiac glycosides may be useful in targeting inflammation at border regions of the brain and offer new options for drug discovery approaches for neuroinflammatory driven degeneration.

Lanatoside C Induces G2/M Cell Cycle Arrest and Suppresses Cancer Cell Growth by Attenuating MAPK, Wnt, JAK-STAT, and PI3K/AKT/mTOR Signaling Pathways.

Cardiac glycosides (CGs) are a diverse family of naturally derived compounds having a steroid and glycone moiety in their structures. CG molecules inhibit the α-subunit of ubiquitous transmembrane protein Na+/K+-ATPase and are clinically approved for the treatment of cardiovascular diseases. Recently, the CGs were found to exhibit selective cytotoxic effects against cancer cells, raising interest in their use as anti-cancer molecules. In this current study, we explored the underlying mechanism responsible for the anti-cancer activity of Lanatoside C against breast (MCF-7), lung (A549), and liver (HepG2) cancer cell lines. Using Real-time PCR, western blot, and immunofluorescence studies, we observed that (i) Lanatoside C inhibited cell proliferation and induced apoptosis in cell-specific and dose-dependent manner only in cancer cell lines; (ii) Lanatoside C exerts its anti-cancer activity by arresting the G2/M phase of cell cycle by blocking MAPK/Wnt/PAM signaling pathways; (iii) it induces apoptosis by inducing DNA damage and inhibiting PI3K/AKT/mTOR signaling pathways; and finally, (iv) molecular docking analysis shows significant evidence on the binding sites of Lanatoside C with various key signaling proteins ranging from cell survival to cell death. Our studies provide a novel molecular insight of anti-cancer activities of Lanatoside C in human cancer cells.

Lanatoside C inhibits cell proliferation and induces apoptosis through attenuating Wnt/ß-catenin/c-Myc signaling pathway in human gastric cancer cell.

Gastric cancer is the third common cause of cancer mortality in the world with poor prognosis and high recurrence due to lack of effective medicines. Our studies revealed that lanatoside C, a FDA-approved cardiac glycoside, had an anti-proliferation effect on different human cancer cell lines (MKN-45; SGC-7901; HN4; MCF-7; HepG2) and gastric cell lines MKN-45 and SGC-7901 were the most sensitive cell lines to lanatoside C. MKN-45 cells treated with lanatoside C showed cell cycle arrest at G2/M phase and inhibition of cell migration. Meanwhile, upregulation of cleaved caspase-9 and cleaved PARP and downregulation of Bcl-xl were accompanied with the loss of mitochondrial membrane potential (MMP) and induction of intracellular reactive oxygen species (ROS). Lanatoside C inhibited Wnt/ß-catenin signaling with downregulation of c-Myc, while overexpression of c-Myc reversed the anti-tumor effect of lanatoside C, confirming that c-Myc is a key drug target of lanatoside C. Furthermore, we discovered that lanatoside C prompted c-Myc degradation in proteasome-ubiquitin pathway with attenuating the binding of USP28 to c-Myc. These findings indicate that lanatoside C targeted c-Myc ubiquitination to inhibit MKN-45 proliferation and support the potential value of lanatoside C as a chemotherapeutic candidate.

Lanatoside C, a cardiac glycoside, acts through protein kinase Cδ to cause apoptosis of human hepatocellular carcinoma cells.

Recent studies have revealed that cardiac glycosides, such as digitalis and digoxin, have anticancer activity and may serve as lead compounds for the development of cancer treatments. The poor prognosis of hepatocellular carcinoma (HCC) patients reflects the development of resistance to current chemotherapeutic agents, highlighting the need for discovering new small-molecule therapeutics. Here, we found that lanatoside C, an anti-arrhythmic agent extracted from Digitalis lanata, inhibited the growth of HCC cells and dramatically decreased tumor volume as well as delayed tumor growth without obvious body weight loss. Moreover, lanatoside C triggered mitochondrial membrane potential (MMP) loss, activation of caspases and translocation of apoptosis-inducing factor (AIF) into the nucleus, which suggests that lanatoside C induced apoptosis through both caspase-dependent and -independent pathways. Furthermore, we discovered that lanatoside C activated protein kinase delta (PKCδ) via Thr505 phosphorylation and subsequent membrane translocation. Inhibition of PKCδ reversed lanatoside C-induced MMP loss and apoptosis, confirming that lanatoside C caused apoptosis through PKCδ activation. We also found that the AKT/mTOR pathway was negatively regulated by lanatoside C through PKCδ activation. In conclusion, we provide the first demonstration that the anticancer effects of lanatoside C are mainly attributable to PKCδ activation.

Liver cancer cells are sensitive to Lanatoside C induced cell death independent of their PTEN status.

BACKGROUND: Hepatocellular carcinoma is the second deadliest cancer with limited treatment options. Loss of PTEN causes the P13K/Akt pathway to be hyperactive which contributes to cell survival and resistance to therapeutics in various cancers, including the liver cancer. Hence molecules targeting this pathway present good therapeutic strategies for liver cancer. HYPOTHESIS: It was previously reported that Cardiac glycosides possessed antitumor activity by inducing apoptosis of multiple cancer cells through oxidative stress. However, whether Cardiac glycoside Lanatoside C can induce oxidative stress in liver cancer cells and induce cell death both in vitro and in vivo remains unknown. METHODS: Cell viability was measured by SRB assay. Cell death analysis was investigated by propidium iodide staining with flow cytometry and PARP cleavage. DCFH-DA staining and cytometry were used for intracellular ROS measurement. Protein levels were analyzed by western blot analysis. Antitumor activity was investigated on mice xenografts in vivo. RESULTS: In this study, we found that Cardiac glycosides, particularly Lanatoside C from Digitalis ferruginea could significantly inhibit PTEN protein adequate Huh7 and PTEN deficient Mahlavu human liver cancer cell proliferation by the induction of apoptosis and G2/M arrest in the cells. Lanatoside C was further shown to induce oxidative stress and alter ERK and Akt pathways. Consequently, JNK1 activation resulted in extrinsic apoptotic pathway stimulation in both cells while JNK2 activation involved in the inhibition of cell survival only in PTEN deficient cells. Furthermore, nude mice xenografts followed by MRI showed that Lanatoside C caused a significant decrease in the tumor size. In this study apoptosis induction by Lanatoside C was characterized through ROS altered ERK and Akt pathways in both PTEN adequate epithelial and deficient mesenchymal liver cancer cells. CONCLUSION: The results indicated that Lanatoside C could be contemplated in liver cancer therapeutics, particularly in PTEN deficient tumors. This is due to Lanatoside C's stress inducing action on ERK and Akt pathways through differential activation of JNK1 and JNK2 by GSK3ß.

Lanatoside C suppressed colorectal cancer cell growth by inducing mitochondrial dysfunction and increased radiation sensitivity by impairing DNA damage repair.

Cardiac glycosides are clinically used for cardiac arrhythmias. In this study, we investigated the mechanism responsible for anti-cancer and radiosensitizing effects of lanatoside C in colorectal cancer cells. Lanatoside C-treated cells showed classic patterns of autophagy, which may have been caused by lanatoside C-induced mitochondrial aggregation or degeneration. This mitochondrial dysfunction was due to disruption of K+ homeostasis, possibly through inhibition of Na+/K+-ATPase activity. In addition, lanatoside C sensitized HCT116 cells (but not HT-29 cells) to radiation in vitro. γ-H2AX, a representative marker of DNA damage, were sustained longer after combination of irradiation with lanatoside C, suggesting lanatoside C impaired DNA damage repair processes. Recruitment of 53BP1 to damaged DNA, a critical initiation step for DNA damage repair signaling, was significantly suppressed in lanatoside C-treated HCT116 cells. This may have been due to defects in the RNF8- and RNF168-dependent degradation of KDM4A/JMJD2A that increases 53BP1 recruitment to DNA damage sites. Although lanatoside C alone reduced tumor growth in the mouse xenograft tumor model, combination of lanatoside C and radiation inhibited tumor growth more than single treatments. Thus, lanatoside C could be a potential molecule for anti-cancer drugs and radiosensitizing agents.

Intracranial AAV-sTRAIL combined with lanatoside C prolongs survival in an orthotopic xenograft mouse model of invasive glioblastoma.

Glioblastoma (GBM) is the most common malignant brain tumor in adults. We designed an adeno-associated virus (AAV) vector for intracranial delivery of secreted, soluble tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) to GBM tumors in mice and combined it with the TRAIL-sensitizing cardiac glycoside, lanatoside C (lan C). We applied this combined therapy to two different GBM models using human U87 glioma cells and primary patient-derived GBM neural spheres in culture and in orthotopic GBM xenograft models in mice. In U87 cells, conditioned medium from AAV2-sTRAIL expressing cells combined with lan C induced 80% cell death. Similarly, lan C sensitized primary GBM spheres to sTRAIL causing over 90% cell death. In mice bearing intracranial U87 tumors treated with AAVrh.8-sTRAIL, administration of lan C caused a decrease in tumor-associated Fluc signal, while tumor size increased within days of stopping the treatment. Another round of lan C treatment re-sensitized GBM tumor to sTRAIL-induced cell death. AAVrh.8-sTRAIL treatment alone and combined with lanatoside C resulted in a significant decrease in tumor growth and longer survival of mice bearing orthotopic invasive GBM brain tumors. In summary, AAV-sTRAIL combined with lanatoside C induced cell death in U87 glioma cells and patient-derived GBM neural spheres in culture and in vivo leading to an increased in overall mice survival.

Modification of the baroreceptor control of atrio-ventricular conduction induced by digitalis in man.

Several studies in animals and in man have suggested that the inhibitory influence of baroreceptors on heart rate and peripheral circulation is enhanced by digitalis. Because the atrio-ventricular node represents a key site for the clinical action of digitalis we studied how baroreceptor control of atrio-ventricular conduction is modified by digitalis at therapeutical doses. In eight subjects heart rate was kept constant by atrial pacing to assess neural influences on atrio-ventricular conduction rate without the modifications caused by simultaneous changes in cardiac cycle length. Arterial baroreceptors were stimulated by increasing or reducing blood pressure (intra-arterial recording), via an iv bolus of phenylephrine or nitroglycerine. The baroreflex sensitivity was assessed in ms . mmHg-1 as the slope of the linear regressions relating the rise or fall in systolic blood pressure to the lengthening or shortening in St- (atrial stimulus artifact) Q interval (ECG recording). The study was performed before and 45 min after iv administration of digitalis (0.8 mg of Lanatoside C). Baroreflex sensitivity during baroreceptor stimulation was 2.9 +/- 1.1 ms . mmHg-1 (mean +/- SE) before digitalis, whereas after digitalis a significantly and markedly greater value of 5.6 +/- 1.5 ms . mmHg-1 was found. Baroreflex sensitivity during baroreceptor deactivation was 0.9 +/- 0.1 ms . mmHg-1 before digitalis, and was not significantly affected by the drug. Thus in man the baroreceptor control of atrio-ventricular conduction is strikingly potentiated by digitalis although this potentiation is only evident in the upper portion of the stimulus-response curve of the reflex.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of cedilanid-D in combination with metoprolol on exercise tolerance and systolic time intervals in angina pectoris.

The interaction between cedilanid-D and metoprolol, a selective beta receptor blocking agent, on exercise tolerance and systolic intervals was studied in 15 patients with angina pectoris. The patients had been treated with metoprolol for several months in a dose of 50 mg, three times daily (one patient received 25 mg three times daily). Each patient participated in two studies separated by at least 1 week. After arriving at the laboratory each received 50 mg of metoprolol orally; thereafter, either cedilanid-D or placebo was infused intravenously in a double-blind study performed in randomized order. When the effect of the drugs was maximal, the systolic intervals and the heart volume were recorded at rest, and the exercise tolerance was tested with a bicycle ergometer. The mean maximal value of plasma concentrations of metoprolol assessed during the study was about 50 ng/ml but the variation among subjects was great (20 to 187 ng/ml). After administration of cedilanid-D there was a shortening of the pre-ejection period and left ventricular ejection time compared with results after placebo; the reduction was similar to that found after administration of cedilanid-D without beta blocking drugs. The total heart volume decreased by an average of 55 ml, but the individual variation was great. The patients' average work capacity, expressed as total work, was not altered by cedilanid-D when compared with results after placebo. No relation was found between initial heart size and the effect of cedilanid-D on capacity for physical work. It therefore appears that there is no indication for the routine use of digitalis during beta blocking therapy in patients with angina pectoris who do not have cardiac failure.

Deleterious effects of taurine in cats with digitalis-induced arrhythmias.

An established model of digitalis toxicity was used to investigate the antiarrhythmic properties of taurine. I.v. doses of taurine ranging from 0.01 to 4.0 mmole/kg were ineffective in converting a deslanoside-induced arrhythmia to sinus rhythm. Indeed, taurine was found to aggravate the arrhythmia and in three experiments precipitated ventricular fibrillation. In addition, pretreatment with 5 mmole/kg taurine i.v. had no significant effect on the doses of deslanoside to produce ventricular arrhythmia and fibrillation.

Interaction of serotonin and deslanoside on cardiac rhythm in the cat.

The present study was performed to determine whether increases in the tissue content of serotonin creatinine SO4 in the periphery would influence the arrhythmogenic effect of deslanoside. This was accomplished by infusing serotonin into anesthetized cats exposed to a subarrhythmic dose of deslanoside, determining doses of deslanoside required to produce ventricular tachycardia and ventricular fibrillation, and determining ventricular pacemaker rate (obtained during vagal-induced sinus node suppression). It was found that animals receiving serotonin creatinine SO4 plus deslanoside exhibited a greater increase in ventricular rate during sinus node suppression than with 5-HT infusion alone. No corresponding increase in ventricular pacemaker rate during sinus node suppression was observed with creatinine SO4 plus deslanoside. In addition, the dose of deslanoside to produce ventricular fibrillation in these animals was significantly correlated with the increase in ventricular pacemaker rate seen during th 5-HT infusion in the presence of deslanoside. Studies were also performed to determine whether the arrhythmogenic interaction of serotonin with deslanoside was associated with alterations in either cardiac tissue, blood or plasma levels of serotonin and 5-hydroxyindoleacetic acid. The data revealed a significant correlation between serotonin content in the left ventricle and the dose of deslanoside required to produce ventricular fibrillation. These results suggest that exogenous serotonin interacts with deslanoside to enhance the arrhythmogenic action of deslanoside.

Effect of arrhythmogenic doses of deslanoside on the uptake of monoamines in brain tissue and in cardiac tissue.

The purpose of our study was to determine whether a toxic arrhythmogenic dose of digitalis administered to an in vivo preparation would affect the neuronal uptake of norepinephrine, serotonin and dopamine in brain tissue and norepinephrine in cardiac tissue. This was investigated by intoxicating anesthetized cats with deslanoside, removing cardiac and brain tissue at the onset of ventricular fibrillation, and examining the ability of brain tissue to accumulate [3H]-NE, [3H]-T-HT and [3H]-DA and cardiac tissue to accumulate [3H]-NE. It was found that deslanoside inhibited uptake of [3H]-NE into the left ventricle and [3H]5-HT into the area postrema. These selective effects may reflect greater blood flow to these regions or different sensitivities of the transport mechanisms for these amines. This inhibition of uptake into both left ventricular tissue and area postrema may contribute to some of the cardiovascular and emetic effects seen with digitalis drugs.

Influence of digitalis on cardiac function before and after autonomic blockade.

The influence of Deslanoside C (D), 1.2 mg intravenously on the systolic time intervals (STI) was assessed in 15 individuals with right ventricular pacemakers, who were studied on two occasions, ten days apart. In the first case D was given under basal conditions, and in the second after autonomic blockade (with practolol 20 mg intravenously and atropine 1.5 and 1.0 mg intravenously) at 1 hour's interval. There were similar changes of the STI with digitalis administration both before and after automic blockade. Autonomic blockade is not necessary for full expression of digitalis action on the human heart, as advocated by some authors to be the case in experimental animals.

[Dromotropic effects of drug combinations. Initial results bearing on a combination of deslanoside and ajmaline]. / Effets dromotropes des associations médicamenteuses. Premiers résultats portant sur l'association deslanoside - ajmaline.

The electrophysiological effects of the cardiotropic drugs have been studied in man by the agency of endocavitary electrocardiography. The effects of drug combinations, which are often prescribed therapeutically, have been studied less often. The authors report the results of a preliminary study of the combination of deslanoside with ajmaline in 26 patients; its effects were compared with those using each drug separately. This combination seems to have true dromotropic effects; although deslanoside alone, in the doses used, does not modify conduction below the bundle of His, it can still act synergistically with ajmaline at this level. A detailed study of the pharmacological effects as a function of the original status of conduction shows that at the level above the bundle His, the dromotropic action is quantitively less on healthy conducting tissue than on abnormal tissue. The effects of ajmaline on the conduction times below the bundle seem to be similar whether or not there is any conduction defect under basal conditions. The difficulties in obtaining and interpreting such measurements in man are discussed in the hope of arriving at a general protocol for studying drug combinations.

[Comparative study of the effect of cycloartane and cardiac glycosides on various parameters of myocardial metabolism in animals]. / Sravnitel'noe izuchenie vliianiia tsikloartanovykh i serdechnykh glikozidov na nekotorye pokazateli metabolizma miokarda u zhivotnykh.

Administration of cycloartane (askendoside D-10 mg/kg, cyclosiversioside F-25 mg/kg) and heart glycosides (strophanthin K-0.36 mg/kg, celanide-1 mg/kg) for 3-10 days is found to exert unidirectional effect on the indices of carbon, lipid and adenine nucleotide metabolism in animal myocardium under study. Glycogen and ATP content increases under parallel decrease of lactate and nonesterified fatty acid content. Differences in the effect of cycloorthane and heart glycosides and especially on the indices of myocardial carbon metabolism were registered under more prolonged administration. Administration of heart glycosides in contrast to cycloorthane ones promotes a decrease of glycogen level and redox potential and increase of lactate content.

Antiviral activity of lanatoside C against dengue virus infection.

Dengue infection poses a serious threat globally due to its recent rapid spread and rise in incidence. Currently, there is no approved vaccine or effective antiviral drug for dengue virus infection. In response to the urgent need for the development of an effective antiviral for dengue virus, the US Drug Collection library was screened in this study to identify compounds with anti-dengue activities. Lanatoside C, an FDA approved cardiac glycoside was identified as a candidate anti-dengue compound. Our data revealed that lanatoside C has an IC50 of 0.19µM for dengue virus infection in HuH-7 cells. Dose-dependent reduction in dengue viral RNA and viral proteins synthesis were also observed upon treatment with increasing concentrations of lanatoside C. Time of addition study indicated that lanatoside C inhibits the early processes of the dengue virus replication cycle. Furthermore, lanatoside C can effectively inhibit all four serotypes of dengue virus, flavivirus Kunjin, alphavirus Chikungunya and Sindbis virus as well as the human enterovirus 71. These findings suggest that lanatoside C possesses broad spectrum antiviral activity against several groups of positive-sense RNA viruses.