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Toxins May 2021Cardiac glycosides (CGs), toxins well-known for numerous human and cattle poisoning, are natural compounds, the biosynthesis of which occurs in various plants and... (Review)
Review
Cardiac glycosides (CGs), toxins well-known for numerous human and cattle poisoning, are natural compounds, the biosynthesis of which occurs in various plants and animals as a self-protective mechanism to prevent grazing and predation. Interestingly, some insect species can take advantage of the CG's toxicity and by absorbing them, they are also protected from predation. The mechanism of action of CG's toxicity is inhibition of Na/K-ATPase (the sodium-potassium pump, NKA), which disrupts the ionic homeostasis leading to elevated Ca concentration resulting in cell death. Thus, NKA serves as a molecular target for CGs (although it is not the only one) and even though CGs are toxic for humans and some animals, they can also be used as remedies for various diseases, such as cardiovascular ones, and possibly cancer. Although the anticancer mechanism of CGs has not been fully elucidated, yet, it is thought to be connected with the second role of NKA being a receptor that can induce several cell signaling cascades and even serve as a growth factor and, thus, inhibit cancer cell proliferation at low nontoxic concentrations. These growth inhibitory effects are often observed only in cancer cells, thereby, offering a possibility for CGs to be repositioned for cancer treatment serving not only as chemotherapeutic agents but also as immunogenic cell death triggers. Therefore, here, we report on CG's chemical structures, production optimization, and biological activity with possible use in cancer therapy, as well as, discuss their antiviral potential which was discovered quite recently. Special attention has been devoted to digitoxin, digoxin, and ouabain.
Topics: Animals; Antineoplastic Agents; Cardiac Glycosides; Cattle; Digitoxin; Digoxin; Humans; Molecular Targeted Therapy; Neoplasms; Ouabain; Sodium-Potassium-Exchanging ATPase
PubMed: 34064873
DOI: 10.3390/toxins13050344 -
Journal of Oral Pathology & Medicine :... Apr 2020Oral submucous fibrosis (OSF) is a chronic, insidious, and progressive oral mucosal disease that affects entire oral cavity and sometimes pharynx. This oral potentially... (Review)
Review
Oral submucous fibrosis (OSF) is a chronic, insidious, and progressive oral mucosal disease that affects entire oral cavity and sometimes pharynx. This oral potentially malignant disorder has a high rate of malignant transformation (7%-30%) to oral squamous cell carcinoma (OSCC), posing global problems for public health. Due to enormous efforts dedicated to this disease in the past decades, there have been significant advances in identification of its etiology and pathogenesis as well as development of corresponding therapeutic approaches, in spite of several challenges. This study reviewed the existing literature concerning OSF in Asian countries, encompassing its etiology, histopathology, pathogenesis, clinical manifestations, diagnosis and differential diagnosis, and treatments. For improving treatment of OSF, the multifactorial etiology analysis, incorporation of effective molecular pathways, cytokines and cells for mechanism illustration, and integration of multidisciplinary modalities were also expounded to guide future research and clinical practice.
Topics: Carcinoma, Squamous Cell; Cell Transformation, Neoplastic; Digitoxigenin; Humans; Mouth Neoplasms; Oral Submucous Fibrosis
PubMed: 31310693
DOI: 10.1111/jop.12924 -
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 -
Global Cardiology Science & Practice Apr 2021We present the case of a 34-year-old woman with recurrent depressive disorder who ingested purple foxglove with suicidal intent. She bought a foxglove plant over the... (Review)
Review
We present the case of a 34-year-old woman with recurrent depressive disorder who ingested purple foxglove with suicidal intent. She bought a foxglove plant over the internet and used all of its leaves to make a tea that she then drank over a period of a few hours. Seventeen hours later, she developed abdominal pain, emesis and bradycardia and was admitted via the emergency department to the intensive care unit for further treatment and monitoring. The plasma digoxin concentration measured 3.53 nmol/l (therapeutic reference range 0.77-1.50 nmol/l) 21 hours after ingestion of the tea. She remained heamodynamically and neurologically stable, was treated with antiemetics and simple analgesia and did not require digoxin-specific antibodies. Despite normal renal function, her plasma digoxin half-life was prolonged (estimated 76 h), reflecting the long half-life of the parent compound digitoxin which is the main cardiac glycoside in . She was transferred to psychiatric care 48 h after admission. In this report, we compare this case to other similar cases, which to date have only been rarely reported in the literature.
PubMed: 34036088
DOI: 10.21542/gcsp.2021.2 -
Chemico-biological Interactions Jan 2022Colon cancer patients with mutant KRAS are resistant to cetuximab, an antibody directed against the epidermal growth factor receptor. New treatment options are needed to...
Colon cancer patients with mutant KRAS are resistant to cetuximab, an antibody directed against the epidermal growth factor receptor. New treatment options are needed to improve survival in patients with KRAS mutated colorectal cancer. Digitoxin is a cardiotonic drug, which has been demonstrated to exhibit anticancer effects in a number of cancers. However, the anticancer mechanisms of digitoxin in KRAS mutant human colon cancer cells remain elusive. Our result demonstrated that digitoxin but not cetuximab markedly decreased the expression of hypoxia-inducible factor-1α (HIF-1α), signal transducer and activator of transcription 3 (STAT3) and p-STAT3 protein in KRAS mutant colon cancer cells. Further analysis revealed that digitoxin inhibited HIF-1α protein synthesis, without affecting the expression level of HIF-1α mRNA or degradation of HIF-1α protein. The phosphorylation levels of ribosomal protein S6 kinase (p70S6K) and eIF4E binding protein-1 (4E-BP1) were significantly suppressed by digitoxin. Digitoxin inhibited the expression and activation of STAT3 through upregulation of phosphatase and tensin homolog deleted on chromosome ten (PTEN), SHP1 and protein inhibitors of activated STAT3 (PIAS3) and direct binding to STAT3. Meanwhile, digitoxin inhibited HIF-1α in STAT3-independent manner in KRAS mutant colon cancer cells. Moreover, digitoxin promoted apoptosis and inhibited proliferation and migration, which was potentially mediated by suppression of HIF-1α and STAT3. We also found that digitoxin administration inhibited tumor growth in a mouse xenograft model. Taken together, our findings highlight the therapeutic potential of digitoxin for the treatment of cetuximab-resistant human colon cancer.
Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Movement; Cell Proliferation; Digitoxin; Down-Regulation; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Mice; Mutation; Neoplasms; Proto-Oncogene Proteins p21(ras); STAT3 Transcription Factor; Signal Transduction; Xenograft Model Antitumor Assays
PubMed: 34717917
DOI: 10.1016/j.cbi.2021.109729 -
Biochemical Pharmacology Apr 2024We previously showed that digitoxin inhibits angiogenesis and cancer cell proliferation and migration and these effects were associated to protein tyrosine kinase 2...
We previously showed that digitoxin inhibits angiogenesis and cancer cell proliferation and migration and these effects were associated to protein tyrosine kinase 2 (FAK) inhibition. Considering the interactions between FAK and Rho GTPases regulating cell cytoskeleton and movement, we investigated the involvement of RhoA and Rac1 in the antiangiogenic effect of digitoxin. Phalloidin staining of human umbilical vein endothelial cells (HUVECs) showed the formation of stress fibers in cells treated with 10 nM digitoxin. By Rhotekin- and Pak1- pull down assays, detecting the GTP-bound form of GTPases, we observed that digitoxin (10-25 nM) induced sustained (0.5-6 h) RhoA activation with no effect on Rac1. Furthermore, inhibition of HUVEC migration and capillary-like tube formation by digitoxin was counteracted by hindering RhoA-ROCK axis with RhoA silencing or Y-27632 treatment. Digitoxin did not decrease p190RhoGAP phosphorylation at Tyr1105 (a site targeted by FAK), suggesting that RhoA activation was independent from FAK inhibition. Because increasing evidence points to a redox regulation of RhoA, we measured intracellular ROS and found that digitoxin treatment enhanced ROS levels in a concentration-dependent manner (1-25 nM). Notably, the flavoprotein inhibitor DPI or the pan-NADPH oxidase (NOX) inhibitor VAS-2870 antagonized both ROS increase and RhoA activation by digitoxin. Our results provide evidence that inhibition of HUVEC migration and tube formation by digitoxin is dependent on ROS production by endothelial NOX, which leads to the activation of RhoA/ROCK pathway. Digitoxin effects on proteins regulating cytoskeletal organization and cell motility could have a wider impact on cancer progression, beyond the antiangiogenic activity.
Topics: Humans; Reactive Oxygen Species; Digitoxin; Human Umbilical Vein Endothelial Cells; Focal Adhesion Kinase 1; Phosphorylation; Cell Movement; NADPH Oxidases; rhoA GTP-Binding Protein; rho-Associated Kinases
PubMed: 38342347
DOI: 10.1016/j.bcp.2024.116049 -
Frontiers in Immunology 2022Osteoarthritis (OA) is a common orthopedic degenerative disease, leading to high disability in activities of daily living. There remains an urgent need to identify the...
Osteoarthritis (OA) is a common orthopedic degenerative disease, leading to high disability in activities of daily living. There remains an urgent need to identify the underlying mechanisms and identify new therapeutic targets in OA diagnosis and treatment. Circular RNAs (circRNAs) play a role in the development of multiple diseases. Many studies have reported that circRNAs regulate microRNAs (miRNAs) through an endogenous competitive mechanism. However, it remains unclear if an interplay between circRNAs, miRNAs, and target genes plays a deeper regulatory role in OA. Four datasets were downloaded from the GEO database, and differentially expressed circRNAs (DECs), differentially expressed miRNAs (DEMs), and differentially expressed genes (DEGs) were identified. Functional annotation and pathway enrichment analysis of DEGs and DECs were carried out to determine the main associated mechanism in OA. A protein-protein network (PPI) was constructed to analyze the function of, and to screen out, hub DEGs in OA. Based on the artificial intelligence prediction of protein crystal structures of two hub DEGs, TOP2A and PLK1, digitoxin and oxytetracycline were found to have the strongest affinity, respectively, with molecular docking. Subsequently, overlapping DEMs and miRNAs targeted by DECs obtained target DEMs (DETMs). Intersection of DEGs and genes targeted by DEMs obtained target DEGs (DETGs). Thus, a circRNA-miRNA-mRNA regulatory network was constructed from 16 circRNAs, 32 miRNAs, and 97 mRNAs. Three hub DECs have the largest number of regulated miRNAs and were verified through experiments. In addition, the expression level of 16 DECs was validated by RT-PCR. In conclusion, we constructed a circRNA-miRNA-mRNA regulatory network in OA and three new hub DECs, hsa_circ_0027914, hsa_circ_0101125, and hsa_circ_0102564, were identified as novel biomarkers for OA.
Topics: Humans; RNA, Messenger; MicroRNAs; RNA, Circular; Molecular Docking Simulation; Artificial Intelligence; Activities of Daily Living; Gene Regulatory Networks; Gene Expression Profiling; Osteoarthritis
PubMed: 36700234
DOI: 10.3389/fimmu.2022.1050743 -
Biomedicine & Pharmacotherapy =... Sep 2020Nerium oleander L., commonly known as oleander, is a toxic shrub and also a medicinal plant. All parts of oleander are rich in cardiac glycosides that inhibits... (Review)
Review
Nerium oleander L., commonly known as oleander, is a toxic shrub and also a medicinal plant. All parts of oleander are rich in cardiac glycosides that inhibits Na/K-ATPase and induce inotropic effect on the cardiomyocytes. Several pre-clinical and clinical reports indicate acute toxicity due to intentional, accidental and suicidal oleander consumption. Contrarily, oleander is used for the treatment of diverse ailments in traditional medicinal practices around the globe and several evidence-based pre-clinical studies indicated metabolic and immunological health benefits of polyphenol-rich oleander extracts. Thus, the current review aims to address this pharmaco-toxicological conundrum of oleander by addressing the possible role of gut microflora in the differential oleander toxicity. Additionally, a comprehensive account of ethnopharmacological usage, metabolic and immunological health benefits has been documented that supplement the conflicting arguments of pharmaco-toxicological properties of oleander. Finally, by addressing the gap of knowledge of ethnomedicinal, pharmacological and toxicological reports of oleander, the current review is expected to pave the way to address the differential pharmaco-toxicological effects of oleander.
Topics: Animals; Bacteria; Biotransformation; Ethnopharmacology; Gastrointestinal Microbiome; Humans; Intestines; Nerium; Plant Extracts; Plants, Medicinal; Risk Assessment
PubMed: 32563990
DOI: 10.1016/j.biopha.2020.110422 -
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