Disruption of cellular energy balance by suramin in intact human prostatic carcinoma cells, a likely antiproliferative mechanism.

The antiparasitic drug, suramin, has antiproliferative effects in human carcinoma cells. It has been suggested that this occurs through blockade of growth factor-receptor interactions. Three types of evidence that suramin rapidly inhibits cellular respiration or disrupts cellular energy balance in intact cells of the human prostate carcinoma cell line, DU145, are presented. Beginning at approximately 10(-4) M, suramin rapidly causes dose-dependent inhibition of tetrazolium conversion by mitochondrial dehydrogenases in intact cells, demonstrating an inhibition of respiration. This effect is reversed by exchange with suramin-free media but not by pretreatment with serum, epidermal growth factor, insulin-like growth factor I, acidic and basic fibroblast growth factors, or calcium. Rhodamine 123 (10 micrograms/ml) uptake by mitochondria in intact DU145 cells is inhibited in the presence of 10(-3) M suramin. Treatment with 10(-4)-10(-3) M suramin causes the loss of rhodamine 123 from cells with mitochondria prestained with rhodamine 123, indicating that suramin is acting as an ionophore or respiratory poison. Also shown by electron microscopy are progressive toxic changes in mitochondria of DU145 cells within 1 h after treatment with 10(-4) M suramin. These data indicate that in intact DU145 cells 10(-4) M suramin rapidly disrupts cellular energy balance or respiration as seen by three studies of mitochondrial state. Disruption of energy balance or respiration represents a likely antiproliferative mechanism, as is thought to be a primary mechanism for the action of suramin in parasitic diseases. This proposed mechanism of action for suramin can explain the most prominent observed clinical toxicities of nephrotoxicity, adrenal toxicity, coagulopathy, and demyelinating neuropathy.     

Synergistic and inhibitory interactions in the in vitro control of murine megakaryocyte colony formation

The formation of megakaryocyte colonies in agar cultures of murine bone marrow or spleen cells can be stimulated by the addition of interleukin-3 (IL-3), erythropoietin (EPO), thrombopoietin (TPO), or IL-6. However, greater numbers of colonies developed if combinations of two or more of these stimuli were used, particularly combinations including stem cell factor, with maximal numbers of colonies developing with the combination of stem cell factor plus IL-3 plus EPO. The data indicate that most committed progenitor cells in the megakaryocyte lineage were unusual in that they required stimulation by two or more hematopoietic growth factors. In tests using a range of growth factors, G-CSF was exceptional in that it consistently specifically inhibited megakaryocyte colony formation stimulated by EPO, TPO, or IL-6 but not that stimulated by IL-3. The mechanisms involved in this inhibitory action of G-CSF are unknown, but the inhibitory action could be of relevance for the dose-dependent lowering of platelet levels observed in some subjects injected with G-CSF.     

Oleuropein Counteracts Both the Proliferation and Migration of Intra- and Extragonadal Seminoma Cells

Recent and growing literature has reported that oleuropein (OLE), the main polyphenol in olive leaf extract, inhibits tumor cell proliferation and reduces the invasiveness properties of cancer cells; therefore, OLE may play a significant role in the development of new drugs for cancer treatment. These antineoplastic properties have been reported in many experimental cancer models, but the effect of OLE on seminoma cells is yet to be evaluated. In the present study, we demonstrate, for the first time, that OLE reduces cell viability in both intra- and extragonadal TCAM-2 and SEM-1 seminoma cells, respectively, in a dose-dependent manner. As shown by Western-blot analysis, OLE exposure reduced cyclin-D1 expression and upregulated p21^Cip/WAF1, concomitantly affecting the upstream pathway of NF-κB, leading to the reduction of its nuclear content, thereby suggesting that OLE could modulate cell-cycle regulators by inhibiting NF-κB. Moreover, Annexin V staining revealed that OLE induced apoptosis in cancer cells and upregulated the pro-apoptotic factor BAX. Through wound-healing scratch and transmigration assays, we also demonstrated that OLE significantly reduced the migration and motility of TCAM-2 and SEM-1 cells, and downregulated the expression of TGFβ-1, which is known to be the main pro-fibrotic factor involved in the acquisition of the migratory and invasive properties of cancer cells. Collectively, our results indicate that OLE reduces seminoma cell proliferation, promotes apoptosis, and counteracts cell migration and motility. Further studies are needed to explore the molecular mechanisms underlying these observed effects.     

Direct Current Cardioversion in Atrial Fibrillation Patients on Edoxaban Therapy Versus Vitamin K Antagonists: a Real-world Propensity Score–Matched Study

Cardiovascular Drugs and Therapy - The purpose of the present study was to compare the long-term effectiveness and safety of newly initiated anticoagulation with edoxaban (EDO) versus uninterrupted...     

A systematic investigation of forensic hair decontamination procedures and their limitations

The effectiveness of decontamination procedures used for the removal of external drug contamination in forensic hair analysis is an ongoing debate. This investigation evaluated wash methods complying with Society of Hair Testing (SoHT) guidelines and their capacity to remove cocaine (COC) and methamphetamine (MA) from artificially contaminated hair. The most effective decontamination method was determined using a systematic approach, involving (1) an initial washing solvent screen, (2) optimization of wash duration, (3) comparison of sequential wash methods, and (4) reanalysis of clinical hair samples. For analysis, hair was subjected to micro‐pulverized methanolic extraction prior to quantitation by ultra‐high performance liquid chromatography?tandem mass spectrometry (UHPLC?MS/MS). Methanol (MeOH) and 0.1 M phosphate buffer (pH 6) were the most effective organic and aqueous solvents, respectively, removing 28%–38% of COC and 16%–31% of MA. Wash durations longer than 30–60 minutes did not remove additional amounts, and a more efficient sequential wash method was subsequently developed. Despite this, the interpretation of reportable results relative to the SoHT cut‐off levels was unchanged for most clinical hair samples reanalyzed after washing by agitation for 30 minutes with MeOH. These findings highlight the inability of decontamination solvents to completely remove external COC and MA contamination from hair, including wash methods adhering to SoHT guidelines.     

Characterization of thrombopoietin (TPO)-responsive progenitor cells in adult mouse bone marrow with in vivo megakaryocyte and erythroid potential

Hematopoietic progenitor cells are the progeny of hematopoietic stem cells that coordinate the production of precise numbers of mature blood cells of diverse functional lineages. Identification of cell-surface antigen expression associated with hematopoietic lineage restriction has allowed prospective isolation of progenitor cells with defined hematopoietic potential. To clarify further the cellular origins of megakaryocyte commitment, we assessed the in vitro and in vivo megakaryocyte and platelet potential of defined progenitor populations in the adult mouse bone marrow. We show that megakaryocytes arise from CD150(+) bipotential progenitors that display both platelet- and erythrocyte-producing potential in vivo and that can develop from the Flt3(-) fraction of the pregranulocyte-macrophage population. We define a bipotential erythroid-megakaryocyte progenitor population, the CD150(+)CD9(lo)endoglin(lo) fraction of Lin(-)cKit(+)IL7 receptor alpha(-)FcγRII/III(lo)Sca1(-) cells, which contains the bulk of the megakaryocyte colony-forming capacity of the bone marrow, including bipotential megakaryocyte-erythroid colony-forming capacity, and can generate both erythrocytes and platelets efficiently in vivo. This fraction is distinct from the CD150(+)CD9(hi)endoglin(lo) fraction, which contains bipotential precursors with characteristics of increased megakaryocytic maturation, and the CD150(+)CD9(lo)endoglin(hi) fraction, which contains erythroid lineage-committed cells. Finally, we demonstrate that bipotential erythroid-megakaryocyte progenitor and CD150(+)CD9(hi)endoglin(lo) cells are TPO-responsive and that the latter population specifically expands in the recovery from thrombocytopenia induced by anti-platelet serum.