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Molecules (Basel, Switzerland) Mar 2021Maintenance of Na and K gradients across the cell plasma membrane is an essential process for mammalian cell survival. An enzyme responsible for this process,... (Review)
Review
Maintenance of Na and K gradients across the cell plasma membrane is an essential process for mammalian cell survival. An enzyme responsible for this process, sodium-potassium ATPase (NKA), has been currently extensively studied as a potential anticancer target, especially in lung cancer and glioblastoma. To date, many NKA inhibitors, mainly of natural origin from the family of cardiac steroids (CSs), have been reported and extensively studied. Interestingly, upon CS binding to NKA at nontoxic doses, the role of NKA as a receptor is activated and intracellular signaling is triggered, upon which cancer cell death occurs, which lies in the expression of different NKA isoforms than in healthy cells. Two major CSs, digoxin and digitoxin, originally used for the treatment of cardiac arrhythmias, are also being tested for another indication-cancer. Such drug repositioning has a big advantage in smoother approval processes. Besides this, novel CS derivatives with improved performance are being developed and evaluated in combination therapy. This article deals with the NKA structure, mechanism of action, activity modulation, and its most important inhibitors, some of which could serve not only as a powerful tool to combat cancer, but also help to decipher the so-far poorly understood NKA regulation.
Topics: Animals; Antineoplastic Agents; Brain Neoplasms; Clinical Trials as Topic; Digitoxin; Digoxin; Drug Repositioning; Enzyme Inhibitors; Glioblastoma; Humans; Isoenzymes; Lung Neoplasms; Models, Molecular; Ouabain; Protein Binding; Protein Conformation; Sodium-Potassium-Exchanging ATPase
PubMed: 33800655
DOI: 10.3390/molecules26071905 -
Inhibitory Effects of Digoxin and Digitoxin on Cell Growth in Human Ovarian Cancer Cell Line SKOV-3.Integrative Cancer Therapies 2021Cardiac glycosides (CGs) possess a chemical structure similar to steroids, and are inhibitors of the sodium potassium pump. An anti-tumor effect of CGs in breast and...
BACKGROUND
Cardiac glycosides (CGs) possess a chemical structure similar to steroids, and are inhibitors of the sodium potassium pump. An anti-tumor effect of CGs in breast and prostate cancers has been reported, but the effect of CGs on ovarian cancer is still unclear.
AIMS
In this study, the effects of CGs on proliferation, cytotoxicity and cell cycle of ovarian cancer cell line (SKOV-3) have been investigated.
PROCEDURE
The cell proliferation and cytotoxicity were detected by MTT assay and LDH activity assay, respectively. CGs, at concentrations higher than IC50, decreased cell proliferation and showed increased cytotoxicity toward SKOV-3 cells. The colony-formation ability was reduced after treatment with digoxin and digitoxin for 10 days. Furthermore, we explored the effect of digoxin and digitoxin on the distribution of cell cycle by flow cytometry.
RESULTS
Results revealed that both digoxin and digitoxin led to cell cycle arrest in G/G phase with 24 or 48 hours, but the arrest of G/G phase was not observed at 72 hours. We evaluated the percentage of hypodiploid cell population as an index of the cellular fragments through flow cytometry. The data indicated that cellular fragments were significantly increased by treating with digitoxin at the concentrations of IC50 and 10 M for 72 hours.
CONCLUSION
Taken together, these data suggest that CGs decreased cell proliferation and increased cytotoxicity through cell cycle arrest at the G/G phase. CGs have anti-tumor effect in SKOV-3 cells and might be a potential therapeutic drug for ovarian cancer. Since this study is a preliminary investigation of CGs on SKOV-3 cells, more experiments might be performed in the future. Furthermore, more ovarian cancer cell lines might also be employed in the future studies to confirm the effect of CGs in ovarian cancer.
Topics: Cell Cycle; Cell Line; Cell Proliferation; Digitoxin; Digoxin; Female; Humans; Male; Ovarian Neoplasms
PubMed: 33736483
DOI: 10.1177/15347354211002662 -
Biomaterials Mar 2021Cancer immunotherapy, particularly the inhibition of immune checkpoints with neutralizing antibodies, has revolutionized the treatment of some cancer patients. However,...
Cancer immunotherapy, particularly the inhibition of immune checkpoints with neutralizing antibodies, has revolutionized the treatment of some cancer patients. However, immune checkpoint blockade has not provided survival benefits to most patients with colorectal and ovarian cancers. This work reports the design of acid-sensitive core-shell nanoscale coordination polymer particles (NCP) comprising a carboplatin prodrug and an siRNA against PD-L1 (siPD-L1) in the core and digitoxin on the shell for tri-modality cancer therapy. Upon cellular uptake, NCP particles rapidly burst in acidic organelles to release carboplatin for apoptosis, digitoxin for inducing immunogenicity, and siPD-L1 for PD-L1 knockdown. With long blood circulation and high tumor accumulation, NCP particles efficiently suppress the growth and metastasis of syngeneic cancers through reactivating innate and adaptive immune responses. NCP particles thus provide a promising platform to synergistically combine chemotherapy and immunotherapy for the treatment of advanced and aggressive cancers.
Topics: Carboplatin; Humans; Immunotherapy; Nanoparticles; Neoplasms; Polymers
PubMed: 33561626
DOI: 10.1016/j.biomaterials.2021.120690 -
Molecular Pharmacology Mar 2021Recent studies have revealed that Na/K-ATPase (NKA) can transmit signals through ion-pumping-independent activation of pathways relayed by distinct intracellular...
Recent studies have revealed that Na/K-ATPase (NKA) can transmit signals through ion-pumping-independent activation of pathways relayed by distinct intracellular protein/lipid kinases, and endocytosis challenges the traditional definition that cardiotonic steroids (CTS) are NKA inhibitors. Although additional effects of CTS have long been suspected, revealing its agonist impact through the NKA receptor could be a novel mechanism in understanding the basic biology of NKA. In this study, we tested whether different structural CTS could trigger different sets of NKA/effector interactions, resulting in biased signaling responses without compromising ion-pumping capacity. Using purified NKA, we found that ouabain, digitoxigenin, and somalin cause comparable levels of NKA inhibition. However, although endogenous ouabain stimulates both protein kinases and NKA endocytosis, digitoxigenin and somalin bias to protein kinases and endocytosis, respectively, in LLC-PK1 cells. The positive inotropic effects of CTS are traditionally regarded as NKA inhibitors. However, CTS-induced signaling occurs at concentrations at least one order of magnitude lower than that of inotropy, which eliminates their well known toxic actions on the heart. The current study adds a novel mechanism that CTS could exert its biased signaling properties through the NKA signal transducer. SIGNIFICANCE STATEMENT: Although it is now well accepted that NKA has an ion-pumping-independent signaling function, it is still debated whether direct and conformation-dependent NKA/effector interaction is a key to this function. Therefore, this investigation is significant in advancing our understanding of the basic biology of NKA-mediated signal transduction and gaining molecular insight into the structural elements that are important for cardiotonic steroid's biased action.
Topics: Animals; Cardiac Glycosides; Cell Survival; Digitoxigenin; Gene Expression Regulation; Glycosides; LLC-PK1 Cells; Ouabain; Signal Transduction; Sodium-Potassium-Exchanging ATPase; Swine
PubMed: 33495275
DOI: 10.1124/molpharm.120.000101 -
Biomedicine & Pharmacotherapy =... Apr 2021Cancer is one of the main causes of death in the world and thus a global public health problem. Among the treatments available for cancer are surgery, radiotherapy, and...
Cancer is one of the main causes of death in the world and thus a global public health problem. Among the treatments available for cancer are surgery, radiotherapy, and chemotherapy. Currently, there is increased interest in the combination of two or more antitumor agents to achieve a synergistic effect in cancer therapy. Doxorubicin (DOX), a chemotherapeutic which has a potent antineoplastic action, has been used in the treatment of various tumors. However, the use of DOX is limited, mainly due to the cardiotoxicity. Therefore, nanostructured systems, such as liposomes, have been developed to carry this drug and target the tumor region, since tumor tissues present enhanced permeability and retention for nanosystems. Cardiac glycosides, such as digitoxin, have recently shown great antitumor potential despite the low therapeutic index which may limit their use. Furthermore, some compounds of this class have low water solubility, which makes their in vivo administration difficult. In this context, liposomes represent a valid strategy to carry simultaneously antitumor drugs allowing their intravenous administration. In this study, liposomes loaded with glucoevatromonoside containing peracetylated glucose hydroxyl groups (GEVPG) and DOX at molar ratio of 1:1 (SpHL-GEVPG:DOX 1:1) were developed, and their chemical and physicochemical properties were evaluated. This formulation presented a combination index (CI) lower than 1 at inhibitory concentration of 90 % growth (IC) for three human breast tumor lines evaluated (0.52 ± 0.39 for MDA-MB-231, 0.19 ± 0.13 for MCF-7, and 0.99 ± 0.09 for SKBR-3). These results indicate a synergistic cytotoxic effect of the GEVPG and DOX combination encapsulated in liposomes. In addition, SpHL-GEVPG:DOX 1:1 presented selectivity towards these cancer cells. Long-term in vitro cytotoxicity studies demonstrated that MDA-MB-231 surviving cells after treatment with SpHL-GEVPG:DOX 1:1 did not recover proliferation capacity after 21 d. From the studies of cell cycle and death pathway evaluation, it was observed that SpHL-GEVPG:DOX 1:1 arrested the cell cycle in the G2/M phase and similarly induced apoptosis and necrosis. However, SpHL-GEVPG:DOX at molar ratio of 1:1 showed lower induction of both apoptotic and necrotic pathways compared to free DOX and SpHL-DOX, suggesting that the mechanism of death involved may not be related to necrosis or apoptosis. Lastly, SpHL-GEVPG:DOX 1:1 showed a good storage stability for 90 d at 4 °C. Therefore, the results of the present work indicate the potential use of SpHL-GEVPG:DOX 1:1 as a new anticancer formulation.
Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Breast Neoplasms; Cardenolides; Cell Proliferation; Cell Survival; Dose-Response Relationship, Drug; Doxorubicin; Drug Compounding; Drug Synergism; Female; Humans; Lipids; Liposomes; MCF-7 Cells; Necrosis; Time Factors
PubMed: 33486211
DOI: 10.1016/j.biopha.2020.111123 -
Foods (Basel, Switzerland) Jan 2021Cardiac glycosides (CGs) represent a group of sundry compounds of natural origin. Most CGs are potent inhibitors of Na/K-ATPase, and some are routinely utilized in the...
Cardiac glycosides (CGs) represent a group of sundry compounds of natural origin. Most CGs are potent inhibitors of Na/K-ATPase, and some are routinely utilized in the treatment of various cardiac conditions. Biological activities of other lesser known CGs have not been fully explored yet. Interestingly, the anticancer potential of some CGs was revealed and thereby, some of these compounds are now being evaluated for drug repositioning. However, high systemic toxicity and low cancer cell selectivity of the clinically used CGs have severely limited their utilization in cancer treatment so far. Therefore, in this study, we have focused on two poorly described CGs: hyrcanoside and deglucohyrcanoside. We elaborated on their isolation, structural identification, and cytotoxicity evaluation in a panel of cancerous and noncancerous cell lines, and on their potential to induce cell cycle arrest in the G2/M phase. The activity of hyrcanoside and deglucohyrcanoside was compared to three other CGs: ouabain, digitoxin, and cymarin. Furthermore, by in silico modeling, interaction of these CGs with Na/K-ATPase was also studied. Hopefully, these compounds could serve not only as a research tool for Na/K-ATPase inhibition, but also as novel cancer therapeutics.
PubMed: 33440629
DOI: 10.3390/foods10010136 -
Frontiers in Pharmacology 2020Female hormones and sex-specific factors are established determinants of endothelial function, yet their relative contribution to human endothelium phenotypes has not...
Female hormones and sex-specific factors are established determinants of endothelial function, yet their relative contribution to human endothelium phenotypes has not been defined. Using human umbilical vein endothelial cells (HUVECs) genotyped by donor's sex, we investigated the influence of sex and estrogenic agents on the main steps of the angiogenic process and on key proteins governing HUVEC metabolism and migratory properties. HUVECs from female donors (fHUVECs) showed increased viability ( < 0.01) and growth rate ( < 0.01) compared with those from males (mHUVECs). Despite higher levels of G-protein coupled estrogen receptor (GPER) in fHUVECs ( < 0.001), treatment with 17β-estradiol (E2) and the selective GPER agonist G1 (both 1-100 nM) did not affect HUVEC viability. Migration and tubularization under physiological conditions were higher in fHUVECs than in mHUVECs ( < 0.05). E2 treatment (1-100 nM) upregulated the glycolytic activator PFKFB3 with higher potency in fHUVECs than in mHUVECs, despite comparable baseline levels. Moreover, Y576/577 phosphorylation of focal adhesion kinase (FAK) was markedly enhanced in fHUVECs ( < 0.001), despite comparable Src activation levels. While the PI3K inhibitor LY294002 (25 µM) inhibited HUVEC migration ( < 0.05), Akt phosphorylation levels in fHUVECs and mHUVECs were comparable. Finally, digitoxin treatment, which inhibits Y576/577 FAK phosphorylation, abolished sexual dimorphism in HUVEC migration. These findings unravel complementary modulation of HUVEC functional phenotypes and signaling molecules involved in angiogenesis by hormone microenvironment and sex-specific factors, and highlight the need for sex-oriented pharmacological targeting of endothelial function.
PubMed: 33390959
DOI: 10.3389/fphar.2020.587221 -
Journal of Experimental Pharmacology 2020Over the past 15 years, investigators have reported on the utility and safety of cardiac glycosides for numerous health benefits including those as treatments for... (Review)
Review
Over the past 15 years, investigators have reported on the utility and safety of cardiac glycosides for numerous health benefits including those as treatments for malignant disease, stroke-mediated ischemic injury and certain neurodegenerative diseases. In addition to those, there is a growing body of evidence for novel antiviral effects of selected cardiac glycoside molecules. One unique cardiac glycoside, oleandrin derived from , has been reported to have antiviral activity specifically against 'enveloped' viruses including HIV and HTLV-1. Importantly, a recent publication has presented in vitro evidence for oleandrin's ability to inhibit production of infectious virus particles when used for treatment prior to, as well as after infection by SARS-CoV-2/COVID-19. This review will highlight the known in vitro antiviral effects of oleandrin as well as present previously unpublished effects of this novel cardiac glycoside against Ebola virus, , and Herpes simplex viruses.
PubMed: 33262663
DOI: 10.2147/JEP.S273120 -
IScience Nov 2020Selecting appropriate cell lines to represent a disease is crucial for the success of biomedical research, because the usage of less relevant cell lines could deliver...
Selecting appropriate cell lines to represent a disease is crucial for the success of biomedical research, because the usage of less relevant cell lines could deliver misleading results. However, systematic guidance on cell line selection is unavailable. Here we developed a clinical Genomics-guided Prioritizing Strategy for Cancer Cell Lines (CCL-cGPS) and help to guide this process. Statistical analyses revealed CCL-cGPS selected cell lines were among the most appropriate models. Moreover, we observed a linear correlation between the drug response and CCL-cGPS score of cell lines for breast and thyroid cancers. Using RT4 cells selected by CCL-GPS, we identified mebendazole and digitoxin as candidate drugs against bladder cancer and validate their promising anticancer effect through and experiments. Additionally, a web tool was developed. In conclusion, CCL-cGPS bridges the gap between tumors and cell lines, presenting a helpful guide to select the most suitable cell line models.
PubMed: 33225250
DOI: 10.1016/j.isci.2020.101748 -
Parasitology Research Jan 2021Treatment for visceral leishmaniasis (VL) is hampered mainly by drug toxicity, their high cost, and parasite resistance. Drug development is a long and pricey process,...
Treatment for visceral leishmaniasis (VL) is hampered mainly by drug toxicity, their high cost, and parasite resistance. Drug development is a long and pricey process, and therefore, drug repositioning may be an alternative worth pursuing. Cardenolides are used to treat cardiac diseases, especially those obtained from Digitalis species. In the present study, cardenolide digitoxigenin (DIGI) obtained from a methanolic extract of Digitalis lanata leaves was tested for its antileishmanial activity against Leishmania infantum species. Results showed that 50% Leishmania and murine macrophage inhibitory concentrations (IC and CC, respectively) were of 6.9 ± 1.5 and 295.3 ± 14.5 μg/mL, respectively. With amphotericin B (AmpB) deoxycholate, used as a control drug, values of 0.13 ± 0.02 and 0.79 ± 0.12 μg/mL, respectively, were observed. Selectivity index (SI) values were of 42.8 and 6.1 for DIGI and AmpB, respectively. Preliminary studies suggested that the mechanism of action for DIGI is to cause alterations in the mitochondrial membrane potential, to increase the levels of reactive oxygen species and induce accumulation of lipid bodies in the parasites. DIGI was incorporated into Pluronic® F127-based polymeric micelles, and the formula (DIGI/Mic) was used to treat L. infantum-infected mice. Miltefosine was used as a control drug. Results showed that animals treated with either miltefosine, DIGI, or DIGI/Mic presented significant reductions in the parasite load in their spleens, livers, bone marrows, and draining lymph nodes, as well as the development of a specific Th1-type response, when compared with the controls. Results obtained 1 day after treatment were corroborated with data corresponding to 15 days after therapy. Importantly, treatment with DIGI/Mic induced better parasitological and immunological responses when compared with miltefosine- and DIGI-treated mice. In conclusion, DIGI/Mic has the potential to be used as a therapeutic agent to protect against L. infantum infection, and it is therefore worth of consideration in future studies addressing VL treatment.
Topics: Amphotericin B; Animals; Antiprotozoal Agents; Deoxycholic Acid; Digitoxigenin; Drug Combinations; Drug Repositioning; Female; Leishmania infantum; Leishmaniasis, Visceral; Liver; Macrophages; Membrane Potential, Mitochondrial; Mice; Mice, Inbred BALB C; Micelles; Parasite Load; Poloxamer; Reactive Oxygen Species; Spleen
PubMed: 33191446
DOI: 10.1007/s00436-020-06971-2