Synthesis of (1,3,4-thiadiazol-2-yl)-acrylamide derivatives as potential antitumor agents against acute leukemia cells

A lead compound with the (1,3,4-thiadiazol-2-yl)-acrylamide scaffold was discovered to have significant cytotoxicity on several tumor cell lines in an in-house cell-based screening. A total of 60 derivative compounds were then synthesized and tested in a CCK-8 cell viability assay. Some of them exhibited improved cytotoxic activities. The most potent compounds had IC₅₀ values of 1–5 μM on two acute leukemia tumor cell lines, i.e. RS4;11 and HL-60. Flow cytometry analysis of several active compounds and detection of caspase activation indicated that they induced caspase-dependent apoptosis. It was also encouraging to observe that these compounds did not have obvious cytotoxicity on normal cells, i.e. IC₅₀ > 50 μM on HEK-293T cells. Although the molecular targets of this class of compound are yet to be revealed, our current results suggest that this class of compound represents a new possibility for developing drug candidates against acute leukemia.     

Rutin decreases lipopolysaccharide-induced acute lung injury via inhibition of oxidative stress and the MAPK–NF-κB pathway

Acute lung injury (ALI) is a serious disease with unacceptably high mortality and morbidity rates. Up to now, no effective therapeutic strategy for ALI has been established. Rutin, quercetin-3-rhamnosyl glucoside, expresses a wide range of biological activities and pharmacological effects, such as anti-inflammatory, antihypertensive, anticarcinogenic, vasoprotective, and cardioprotective activities. Pretreatment with rutin inhibited not only histopathological changes in lung tissues but also infiltration of polymorphonuclear granulocytes into bronchoalveolar lavage fluid in lipopolysaccharide (LPS)-induced ALI. In addition, LPS-induced inflammatory responses, including increased secretion of proinflammatory cytokines and lipid peroxidation, were inhibited by rutin in a concentration-dependent manner. Furthermore, rutin suppressed phosphorylation of NF-κB and MAPK and degradation of IκB, an NF-κB inhibitor. Decreased activities of antioxidative enzymes such as superoxide dismutase, catalase, glutathione peroxidase, and heme oxygenase-1 caused by LPS were reversed by rutin. At the same time, we found that ALI amelioration by chelation of extracellular metal ions with rutin is more efficacious than with deferoxamine. These results indicate that the protective mechanism of rutin is through inhibition of MAPK–NF-κB activation and upregulation of antioxidative enzymes.     

Studies of the proliferation and differentiation of immature myeloid cells in vitro: 4: Preculture proto-oncogene expression and the behaviour of myeloid leukemia cells in vitro

Studies were conducted to determine the relationship between the pretherapy characteristics of leukemia cells and their behaviour during culture in vitro. Leukemia cells which proliferated well in vitro also proliferated well in vivo. Cells which manifested myeloid or monocytic differentiation in vivo tended to manifest differentiation along these lines in vitro. Cells which manifested high levels of expression of c-fms, c-fes, or triose phosphate isomerase prior to culture were likely to differentiate in vitro, with high levels of c-fes expression being related to myeloid maturation. These observations suggest that differentiation at the molecular level prior to culture is a requisite for leukemia cell differentiation in vitro. The same may be true for differentiation in vivo under the influence of exogenously administered agents such as cytotoxic chemotherapy or recombinant growth factors.     

Effect of cocaine and morphine on neutral endopeptidase activity of human peripheral blood mononuclear cells cultured with lectins

We have tested the effect of alkaloids (cocaine, morphine) and enkephalins on neutral endopeptidase of peripheral blood mononuclear cells activated by lectins. When treated with concanavalin A and cocaine, peripheral blood mononuclear cells showed an enhanced activity (+110 per cent) of the membrane neutral endopeptidase, which was not related to the expression of the common acute lymphoblastic leukemia antigen at the cell surface, although both molecules have the identical amino acid sequence. Phytohemagglutinin-P, morphine and synthetic enkephalins did not induce the activity of neutral endopeptidase nor the expression of common acute lymphoblastic leukemia antigen. Our findings suggested that the drugs of abuse, cocaine and morphine, affected specific membrane constituents without altering proliferation, subcellular localization of membrane enzymes or the surface immune phenotype of peripheral blood mononuclear cells.     

Genome-wide CRISPR Screens Reveal Host Factors Critical for SARS-CoV-2 Infection

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Thymidine kinase isoenzymes in human acute monocytic leukemia

Summary Two thymidine kinase isoenzymes, TK 3 and TK 4, from mononuclear leucocytes from a patient with acute monocytic leukemia, were purified and characterized in regard to the molecular weights and kinetic properties.The molecular weights of TK 3 and TK 4 were 60 000 and 45 000, respectively. In the presence of 2 mM ATP, the molecular weight of TK 3 increased to 200 000, whereas the molecular weight of TK 4 was unchanged.Studies of the kinetic properties showed clear differences between TK 3 and TK 4. With thymidine as substrate, TK 3 showed biphasic kinetics with a K_m of 22 µM, and TK 4 showed Michaelis-Menten kinetics with a K_m of 0.33 µM With ATP as substrate, TK 3 showed Michaelis-Menten kinetics with a K_m of 100 µM, and TK 4 showed biphasic kinetics with a Km of 3.5 µM. With dTTP as inhibitor, TK 3 showed cooperative inhibition kinetics, and TK 4 showed non-cooperative competitive inhibition kinetics. The dTTP concentration at 50% inhibition was 75 µM for TK 3 but 380 µM for TK 4.Comparison of the molecular weights and the kinetic properties of TK 3 and TK 4 with the corresponding data previously obtained for TK 1 and TK 2 from normal human lymphocytes indicate the existence of four thymidine kinase isoenzymes in human leucocytes.     

Deoxycytidylate deaminase activity in non-stimulated and phytohemagglutinin-stimulated human lymphocytes,and in leukemic cells

Deoxycytidylate deaminase isolated from normal human lymphocytes and from mononuclear leucocytes from patients with acute lymphoblastic leukemia, chronic lymphocytic leukemia and acute monocytic leukemia has been characterized in regard to the substrate, dAMP and the allosteric regulators dCTP and dTTP. The enzymes exhibited sigmoidal initial velocity versus dCMP concentration whereas in the presence of the activator, dCTP, Michaelis-Menten kinetics were obtained.At saturating substrate concentrations dTTP acted as an allosteric inhibitor of the enzyme isolated from non-stimulated as well as from stimulated lymphocytes. However, the enzymes isolated from the leukemic cells had lost the allosteric regulation by dTTP.At low substrate concentrations the competitive inhibitor, dAMP, activated all the enzymes. This activation was abolished in the presence of dCTP which indicates that dAMP might be involved in the regulation of dCMP deaminase activity and thus influence the dCTP and dTTP pools under physiological conditions.Abbreviations dCMP deaminase deoxycytidylate deaminase - PHA Phytohemagglutinin - ALL acute lymphoblastic leukemia - CLL chronic lymphocytic leukemia - AMOL acute monocytic leukemia - WBC white blood cells     

Impact of preconditioning stem cells with all-trans retinoic acid signaling pathway on cisplatin-induced nephrotoxicity by down-regulation of TGFβ1, IL-6, and caspase-3 and up-regulation of HIF1α and VEGF

The survival reduction after transplantation limited the clinical uses of stem cells so the current study explored preconditioning adipose-derived stem cells (ADMSCs) and all-trans retinoic acid (ATRA) effects on cisplatin that caused acute kidney injury (AKI). One hundred and fifty Sprague–Dawley male rats were distributed into five groups: control group; Cisplatin (CIS) group; CIS and ATRA group; CIS and ADMSC group, and CIS, ATRA, and ADMSCs group. Ten rats were euthanized after 3rd, 7th, and 11th days from CIS injection. Renal function, molecular studies, and histopathological analysis were studied. The preconditioning of ADMSCs with ATRA increased the viability of the cells which was reflected in the amelioration of kidney functions after CIS injection by the significant reduction of serum creatinine, microalbuminuria, as well as NO, and the significant rise of creatinine clearance, as well as SOD compared to the group of cisplatin. ATRA also supported ADMSCs by a significant down-regulation of caspase-3, il-6 and TGFβ1, and a significant up-regulation of HIF1, VEGF and CD31 compared to group of cisplatin which reversed the cisplatin effect. ATRA increased renoprotective properties of ADMSCs against cisplatin- induced AKI by reducing the apoptosis, inflammation, and stimulating angiogenesis.