Synthesis of oxovanadium complexes and their apoptosis-inducing activity in leukemia cells

Vanadium complexes with different ligands were synthesized and evaluated for antiproliferative activity on U937 cells. The alkyl chain length of the ligands affected the antiproliferative activity, and two complexes-3b and 4-exhibited strong activities with IC(50) values of 6.02 and 3.90 μM respectively. Annexin V staining and DNA ladder formation indicated that these complexes induced apoptosis in U937 cells.     

Photo-activation of hypericin with low doses of light promotes apparent photo-resistance in human histiocytic lymphoma U937 cells

We have observed that exposure of U937 cells, pre-incubated for 18 h with 0.2 μM hypericin, to 599 nm laser radiation with a fluence of 2.5 J/cm² renders them insensitive to higher light doses. In fact, pre-sensitized cells appear to be fully resistant to light doses that normally determine massive cellular apoptosis in experimental photo-dynamic therapy. The appearance of the photo-resistance, as measured by evaluating the changes in levels of expression of pro and anti apoptotic proteins, PARP fragmentation and cell viability is exclusively observed with exposure to light doses not exceeding 5–6 J/cm². Above this energy, necrosis replaces apoptosis upon photo-stimulation of U937 cells. Here, we describe the appearance of photo-resistance in hypericin-loaded U937 cells, but could not fully unravel the molecular mechanism underlying this process. However, the observed stimulation of the expression of the HSP-70 protein upon photo-induced stress may suggest its involvement in this process.     

2',5,7-Trihydroxy-4',5'-(2,2-dimethylchromeno)-8-(3-hydroxy-3-methylbutyl) flavanone purified from Cudrania tricuspidata induces apoptotic cell death of human leukemia U937 cells

Cellular DNA topoisomerase I is an important target in cancer chemotherapy. A chloroform extract of the root barks of Cudrania tricuspidata showed an inhibitory effect on mammalian DNA topoisomerase I. The topoisomerase I inhibitory compound was purified and identified as 2',5,7-trihydroxy-4',5'-(2,2-dimethylchromeno)-8-(3-hydroxy-3-methylbutyl) flavanone. The compound, temporarily designated as PKH-3, was shown to inhibit the activity of topoisomerase I with IC50 about 1.0 mM. Concentration of 10 microM PKH-3 caused 50% growth inhibition of human cancer cell U937. PKH-3-induced cell death was characterized with the cleavage of poly(ADP-ribose) polymerase (PARP) and pro-caspase 3. Furthermore, PKH-3 induced the fragmentation of DNA into multiples of 180 b.p. (an apoptotic DNA ladder), indicating that the inhibitor triggered apoptosis. This induction of apoptosis by PKH-3 was also confirmed using flow cytometry analysis. Taken together, these results suggest that PKH-3 may function by inhibiting oncogenic disease, at least in part, through the inhibition of topoisomerase I activity.     

Combined inhibition of HDAC and DNMT1 induces p85α/MEKmediated cell cycle arrest by dual target inhibitor 208 in U937 cells

Herein we reported an efficient dual DNMT and HDAC inhibitor 208 with great antiproliferative activity against U937 cells. Further studies revealed 208 affected the whole proteome profile and could induce G1 cell cycle arrest and apoptosis in U937 cells through upregulating CDK inhibitor p16 and downregulating cyclin-dependent kinases and their activators.     

JNK inhibitor SP600125 promotes the formation of polymerized tubulin, leading to G2/M phase arrest, endoreduplication, and delayed apoptosis

The JNK inhibitor SP600125 strongly inhibits cell proliferation in many human cancer cells by blocking cell-cycle progression and inducing apoptosis. Despite extensive study, the mechanism by which SP600125 inhibits mitosis-related effects in human leukemia cells remains unclear. We investigated the effects of SP600125 on the inhibition of cell proliferation and the cell cycle, and on microtubule dynamics in vivo and in vitro. Treatment of synchronized leukemia cells with varying concentrations of SP600125 results in significant G₂/M cell cycle arrest with elevated p21 levels, phosphorylation of histone H3 within 24 h, and endoreduplication with elevated Cdk2 protein levels after 48 h. SP600125 also induces significant abnormal microtubule dynamics in vivo. High concentrations of SP600125 (200 µM) were required to disorganize microtubule polymerization in vitro. Additionally, SP600125-induced delayed apoptosis and cell death was accompanied by significant poly ADP-ribose polymerase (PARP) cleavage and caspase-3 activity in the late phase (at 72 h). Endoreduplication showed a greater increase in ectopic Bcl-2-expressing U937 cells at 72 h than in wild-type U937 cells without delayed apoptosis. These results indicate that Bcl-2 suppresses apoptosis and SP600125-induced G₂/M arrest and endoreduplication. Therefore, we suggest that SP600125 induces mitotic arrest by inducing abnormal spindle microtubule dynamics.     

Synthesis and Cytotoxicity of 6‐Pyrrolidinyl‐2‐(2‐Substituted Phenyl)‐4‐Quinazolinones

In our continuing search for potential anticancer candidates, 2‐(3‐methoxyphenyl)‐6‐pyrrolidinyl‐4‐quinazolinone ( JJC‐1 ) was selected as the lead compound. Starting 5‐pyrrolidinyl‐2‐aminobenzamide was prepared using standard methodology from 5‐chloro‐2‐nitrobenzoic acid by reaction with SOCl₂, NH₃, pyrrolidine, and H₂. The starting benzamide then was reacted with 2‐substituted benzaldehyde or benzoyl chloride in N,N‐dimethylacetamide (DMAC) in the presence of NaHSO₃ at 150 °C. Thermal cyclodehydration/dehydrogenation gave the target 6‐pyrrolidinyl‐2‐(2‐substituted phenyl)‐4‐quinazolinones ( 15–22 ). These target compounds were assayed for their cytotoxicity in vitro against six cancer cell lines, including human monocytic leukemia cells (U937), mouse monocytic leukemia cells (WEHI‐3), human hepatoma cells (HepG2, Hep3B) and human lung carcinoma cells (A549, CH27). Most of them exhibited significant cytotoxic effect toward U937 and WEHI‐3 cells, with EC₅₀ values ranging from 0.30 to 10.10 μM. Compound 19 was investigated further for its action mechanisms. Preliminary findings indicated that compound 19 induced G2/M arrest and apoptosis on U937 cells.     

Association of Ceramide Accumulation with Photodynamic Treatment-Induced Cell Death

Abstract— Ceramide, a stress-induced second messenger, has been associated with apoptosis in several malignant and non-malignant cell lines. We have shown that photodynamic treatment (PDT), using the phthalocyanine photosensitiz-er Pc 4 (HOSiPcOSi[CH₃]₂[CH₂]₃N[CH₃]₂), causes increased ceramide generation and subsequent induction of apoptosis in L5178Y-R (LY-R) mouse lymphoma cells. To test further if ceramide generation accompanies photocytotoxicity, we treated various cell lines with a PDT dose producing a 99-99.9% loss of clonogenicity. Like LY-R cells, human leukemia (U937) cells underwent rapid DNA fragmentation initiating within 1 h after PDT. Similarly, Chinese hamster ovary (CHO) cells showed rapid DNA laddering, beginning 1 h following the treatment. In contrast, mouse radiation-induced fibrosarcoma (RIF-1) cells showed no apoptosis within 24 h post-PDT, as judged by the absence of 50 kbp and oligonucleosome-size DNA fragments, as well as no annexin V binding to cells with preserved membrane integrity. Using the same doses of PDT, we observed a time-dependent ceramide accumulation in all three cell lines. While a significant increase in ceramide levels was reached within 1 and 10 min in U937 and CHO cells, respectively, elevated ceramide production was measured only after 30 min in RIF-1 cells. In addition, exogenous N-acetyl-sphingosine was able to mimic PDT-induced apoptosis in U937 and CHO cells. We suggest that ceramide accumulation is associated with PDT-induced apoptosis and photocytotox-icity.     

Ultrasound-assisted synthesis and anticancer evaluation of new pyrazole derivatives as cell cycle inhibitors

We designed new pyrazole derivatives as inhibitors of the cell cycle kinases and developed a simple environmentally sustainable synthesis process. We synthesized the pyrazolyl thiourea derivatives using rapid ultrasound mediated methods and confirmed their structures by NMR and IR spectra. The apoptosis and necrosis inducing effects of the new compounds were investigated. Cell cycle analysis and expression of genes involved in apoptosis, cell cycle and xenobiotic metabolism were studied. The compounds presented modest apoptotic effects in human cancer cells. The N-[[3-(4-bromophenyl)-1H-pyrazol-5-yl]carbamothioyl]-4-chloro-benzamide compound (4e) induced a significant increase of cells in G2/M phases in conjunction with an increased expression of cyclin A and cyclin B, emerging as a promising anticancer drug, to be further developed in animal models of cancer.     

电场或电磁场和光动力的协同效应对癌细胞失活和坏死的作用(英文)

应用弱正弦波电磁场改变细胞膜的穿透性并引起其失活和坏死.研究中,将人类癌细胞U 937和K 562放置于强度为10mT和39mT(50Hz)的正弦波电磁场内,并依次结合细胞毒素放线菌素 C以及其独特的光动力活性分别进行试验.     

Furocoumarins photolysis products induce differentiation of human erythroid cells

Psoralens, also known as furocoumarins, are a well-known class of photosensitizers largely used in the therapy of various skin disease. In this study we have evaluated the effects of crude pre-irradiated solutions of furocoumarins derivatives on (a) erythroid differentiation and apoptosis of human leukemic K562 cells and (b) hemoglobin synthesis in cultures of human erythroid progenitors derived from the peripheral blood. To prove the activity of a mixture of photoproducts generated by UVA irradiation of the three psoralen derivatives 5-methoxypsoralen (5-MOP) 8-methoxypsoralen (8-MOP), and angelicin (ANG), we employed the human leukemic K562 cell line and the two-phase liquid culture procedure for growing erythroid progenitors. The results obtained demonstrate that pre-irradiated solutions of psoralen derivatives significantly induce erythroid differentiation of K562 cells irrespective of the type of derivative used, suggesting that the active photoproduct(s) share a common structure. Interestingly, solutions of psoralens irradiated in anaerobic conditions do not exhibits erythroid inducing ability, indicating that the effect is mostly due to photooxidized psoralen products. In erythroid precursor cells, psoralens photolysis products stimulates at low concentrations an increase of hemoglobin A and hemoglobin F. Altogether, these data suggest that photoproducts of psoralen warrant further evaluation as potential therapeutic drugs in beta-thalassaemia and sickle cell anaemia.     

Cu(II) complexes with heterocyclic substituted thiosemicarbazones: the case of 5-formyluracil. Synthesis,characterization, x-ray structures,DNA interaction studies,and biological activity

Two new 5-formyluracil thiosemicarbazone (H(3)ut) derivatives, Me-H(3)ut (1) and Me(2)-H(3)ut (2), were synthesized by reacting thiosemicarbazides, mono- and dimethylated on the aminic nitrogen, with 5-formyluracil and were subsequently characterized. These ligands, treated with copper chloride and nitrate, afforded three complexes: [Cu(Me-H(3)ut)Cl(2)].H(2)O (3), [Cu(Me(2)-H(3)ut)Cl(2)].H(2)O (4), and [Cu(Me-H(3)ut)(NO(3))(OH(2))(2)]NO(3) (5). The crystal structures of these complexes have been determined by single-crystal X-ray diffraction. In 3 and 4, a similar pentacoordination is present; the copper atom is surrounded by the ligand SNO donor atoms and by two chloride ions. The structure of 5 consists of [Cu(Me-H(3)ut)(NO(3))(OH(2))(2)](+) cations and nitrate anions. The copper coordination (4 + 2) involves the SNO ligand atoms and a water oxygen in the basal plane; the apical positions are occupied by a second water oxygen and by an oxygen of a monodentate nitrate group. Two biochemical techniques, namely DNA titration in the UV-vis region and thermal denaturation, have been employed to probe the details of DNA binding of these compounds. Analysis of the results suggests that our compounds are able to interact with DNA by electrostatic and groove binding but not by intercalation. The compounds have been also tested in vitro on human leukemic cell line U937, but they are not able to inhibit significantly cell proliferation.     

CD36 signaling inhibits the translation of heat shock protein 70 induced by oxidized low density lipoprotein through activation of peroxisome proliferators-activated receptor ��

Oxidized LDL (OxLDL), a causal factor in atherosclerosis, induces the expression of heat shock proteins (Hsp) in a variety of cells. In this study, we investigated the role of CD36, an OxLDL receptor, and peroxisome proliferator-activated receptor γ (PPARγ) in OxLDL-induced Hsp70 expression. Overexpression of dominant-negative forms of CD36 or knockdown of CD36 by siRNA transfection increased OxLDL-induced Hsp70 protein expression in human monocytic U937 cells, suggesting that CD36 signaling inhibits Hsp70 expression. Similar results were obtained by the inhibition of PPARγ activity or knockdown of PPARγ expression. In contrast, overexpression of CD36, which is induced by treatment of MCF-7 cells with troglitazone, decreased Hsp70 protein expression induced by OxLDL. Interestingly, activation of PPARγ through a synthetic ligand, ciglitazone or troglitazone, decreased the expression levels of Hsp70 protein in OxLDL-treated U937 cells. However, major changes in Hsp70 mRNA levels were not observed. Cycloheximide studies demonstrate that troglitazone attenuates Hsp70 translation but not Hsp70 protein stability. PPARγ siRNA transfection reversed the inhibitory effects of troglitazone on Hsp70 translation. These results suggest that CD36 signaling may inhibit stress-induced gene expression by suppressing translation via activation of PPARγ in monocytes. These findings reveal a new molecular basis for the anti-inflammatory effects of PPARγ.     

Synthesis and biological evaluations of mono‐ and bis‐ferrocene uracil derivatives

Mono‐ ( 3a – 3e and 4a – 4e ) and bis‐ferrocene ( 5a – 5e and 6a – 6e ) conjugated 5‐substituted uracil derivatives that are bridged by 1,2,3‐triazole linker were synthesized. The impact of ferrocene unit and spacer between ferrocene and triazole on radical scavenging potency was observed. Bis‐ferrocenyl uracil derivatives exhibited better antiproliferative activities than their mono‐ferrocenyl analogs. Bis‐ferrocenyl methyl‐ ( 5b ) and halogen‐substituted ( 5e , 6c , and 6d ) uracil derivatives showed pronounced and selective cytostatic activities on colon adenocarcinoma (CaCo‐2) and Burkitt lymphoma (Raji) cells, with higher potency and selectivity than the reference drug 5‐fluorouracil. Generation of reactive oxygen species (ROS) in CaCo‐2 and Raji cells when treated with compounds 5b , 5e , and 6d was observed. Bis‐ferrocenyl 5‐chlorouracil 6c induced significant disruption in mitochondrial membrane potential that is accompanied by activation of apoptosis in CaCo‐2, Raji, and acute lymphoblastic leukemia (CCRF‐CEM) cells, while 6d caused mitochondrial dysfunction and apoptosis induction in CaCo‐2 and Raji cells. Potent antiproliferative activity of 6c and 6d could be associated with mitochondrial membrane potential disruption accompanied by apoptosis induction. Our findings highlighted 6c and 6d with potent and selective antiproliferative activity on CaCo‐2, Raji, and CCRF‐CEM cells that may be associated with targeting cancer cell mitochondria, as a molecular target.     

Novel 1,3-Thiazole Analogues with Potent Activity against Breast Cancer: A Design,Synthesis, In Vitro,and In Silico Study

Breast cancer is the most common cancer in women, responsible for over half a million deaths in 2020. Almost 75% of FDA-approved drugs are mainly nitrogen- and sulfur-containing heterocyclic compounds, implying the importance of such compounds in drug discovery. Among heterocycles, thiazole-based heterocyclic compounds have demonstrated a broad range of pharmacological activities. In the present study, a novel set of 1,3-thiazole derivatives was designed and synthesized based on the coupling of acetophenone derivatives, and phenacyl bromide was substituted as a key reaction step. The activity of synthesized compounds was screened against the proliferation of two breast cancer cell lines (MCF-7 and MDA-MB-231). Almost all compounds exhibited a considerable antiproliferative activity toward the breast cancer cells as compared to staurosporine, with no significant cytotoxicity toward the epithelial cells. Among the synthesized compounds, compound 4 exhibited the most potent antiproliferative activity, with an IC₅₀ of 5.73 and 12.15 µM toward MCF-7 and MDA-MB-231 cells, respectively, compared to staurosporine (IC₅₀ = 6.77 and 7.03 µM, respectively). Exploring the mechanistic insights responsible for the antiproliferative activity of compound 4 revealed that compound 4 possesses a significant inhibitory activity toward the vascular endothelial growth factor receptor-2 (VEGFR-2) with (IC₅₀ = 0.093 µM) compared to Sorafenib (IC₅₀ = 0.059 µM). Further, compound 4 showed the ability to induce programmed cell death by triggering apoptosis and necrosis in MCF-7 cells and to induce cell cycle arrest on MCF-7 cells at the G1 stage while decreasing the cellular population in the G2/M phase. Finally, detailed in silico molecular docking studies affirmed that this class of compounds possesses a considerable binding affinity toward VEGFR2 proteins. Overall, these results indicate that compound 4 could be a promising lead compound for developing potent anti-breast cancer compounds.     

Synthesis and in vitro biological evaluation of farnesylthiosalicylic acid derivatives as anti-tumor carcinoma agents

Novel farnesylthiosahcylic acid(FTA) derivatives 5a-m with different substituted 1,3,4-thiadiazoles were synthesized. Compounds 5b,5c,5e and 5f displayed anti-tumor activities superior to FTA in most cancer cells tested.Furthermore,5e induced tumor cell apoptosis,which was accompanied by lower Bcl-2 expression,but with higher Bax and caspase 3 expression activities in cancer cells.     

Betulinic Acid Restricts Human Bladder Cancer Cell Proliferation In Vitro by Inducing Caspase-Dependent Cell Death and Cell Cycle Arrest,and Decreasing Metastatic Potential

Betulinic acid (BA) is a naturally occurring pentacyclic triterpenoid and generally found in the bark of birch trees (Betula sp.). Although several studies have been reported that BA has diverse biological activities, including anti-tumor effects, the underlying anti-cancer mechanism in bladder cancer cells is still lacking. Therefore, this study aims to investigate the anti-proliferative effect of BA in human bladder cancer cell lines T-24, UMUC-3, and 5637, and identify the underlying mechanism. Our results showed that BA induced cell death in bladder cancer cells and that are accompanied by apoptosis, necrosis, and cell cycle arrest. Furthermore, BA decreased the expression of cell cycle regulators, such as cyclin B1, cyclin A, cyclin-dependent kinase (Cdk) 2, cell division cycle (Cdc) 2, and Cdc25c. In addition, BA-induced apoptosis was associated with mitochondrial dysfunction that is caused by loss of mitochondrial membrane potential, which led to the activation of mitochondrial-mediated intrinsic pathway. BA up-regulated the expression of Bcl-2-accociated X protein (Bax) and cleaved poly-ADP ribose polymerase (PARP), and subsequently activated caspase-3, -8, and -9. However, pre-treatment of pan-caspase inhibitor markedly suppressed BA-induced apoptosis. Meanwhile, BA did not affect the levels of intracellular reactive oxygen species (ROS), indicating BA-mediated apoptosis was ROS-independent. Furthermore, we found that BA suppressed the wound healing and invasion ability, and decreased the expression of Snail and Slug in T24 and 5637 cells, and matrix metalloproteinase (MMP)-9 in UMUC-3 cells. Taken together, this is the first study showing that BA suppresses the proliferation of human bladder cancer cells, which is due to induction of apoptosis, necrosis, and cell cycle arrest, and decrease of migration and invasion. Furthermore, BA-induced apoptosis is regulated by caspase-dependent and ROS-independent pathways, and these results provide the underlying anti-proliferative molecular mechanism of BA in human bladder cancer cells.     

Copper(II) complexes with substituted thiosemicarbazones of alpha-ketoglutaric acid: synthesis, X-ray structures, DNA binding studies, and nuclease and biological activity

New alpha-ketoglutaric acid thiosemicarbazone (H(3)ct) derivatives and their copper complexes were synthesized and characterized by analytical and spectroscopic (IR and NMR) methods. For two of the ligands, Me-H(3)ct and Allyl-H(3)ct, and for a complex, [Cu(Me-Hct)(OH(2))](n) x 2nH(2)O, the X-ray structures were also determined. In the latter the copper atom shows a 4 + 1 pyramidal coordination, a water oxygen appears in the apical position, and three of the basal positions are occupied by the SNO tridentate ligand and the fourth by a carboxylic oxygen of an adjacent molecule that gives rise to a polymeric chain. DNA binding constants were determined, and studies of thermal denaturation profiles and nuclease activity were also performed. Tests in vitro on human leukemia cell line U937 were carried out on cell growth inhibition, cell cycle, and apoptosis induction.     

1,3,4-噁二唑和1,3,4-噻二唑衍生物的设计、合成和生物活性研究

为了寻求新型抗肿瘤药物,设计并合成了一系列新型1,3,4-噁二唑和1,3,4-噻二唑衍生物,对这些化合物在人类四种癌细胞:B-16(皮肤黑色素瘤细胞)、PC-3(人前列腺癌细胞)、U87(人原发性胶质母细胞瘤细胞)和A549(人非小细胞肺癌细胞)进行抗肿瘤活性评价.结果显示部分化合物具有较好的抗肿瘤活性,尤其是5-{6-[4-(2-羟基乙基)哌嗪-1-基]-2-甲基嘧啶-4-基氨基}-[1,3,4-噻二唑-2-羧酸(2-甲氧基苯基)酰胺(8b)]和5-{6-[4-(2-羟基乙基)哌嗪-1-基]-2-甲基嘧啶-4-基氨基}-[1,3,4-噻二唑-2-羧酸(4-甲氧基苯基)酰胺(8c)],对四种癌细胞都显示出较高的抗肿瘤活性,其抑制活性均优于阳性对照达沙替尼,随后对这类化合物抑制肿瘤的可能靶点开展了进一步研究.     

Unusual cycloartane glycosides from Astragalus eremophilus

Eleven new cycloartane-type glycosides, named eremophilosides A-K have been isolated from the aerial parts of Astragalus eremophilus. Their structures were elucidated by MS and NMR experiments and the relative configurational analysis of eremophilosides C and D was carried out on the basis of the recently reported J-based method. Additionally, the cytotoxic activity of these compounds in MCF7 and U937 cell lines was evaluated. All tested compounds, except eremophilosides B, C, and J were found to inhibit slightly the growth (controlling the cell cycle) and/or to induce death processes in U937 cell line, the most susceptible cell line. Eremophilosides A and K resulted the most effective to induce cell death, the first by necrosis while the latter by apoptosis.