SAR studies of brasilicardin A for immunosuppressive and cytotoxic activities

Eleven derivatives (5-13, 15, and 16) of an immunosuppressive and cytotoxic tricyclic terpenoid, brasilicardin A (1), were prepared and assayed for inhibitory effects to the mouse mixed lymphocyte reaction (MLR) and seven human tumor cell lines. The 17N-methyl form (8) of 1 showed the most potent immunosuppressive activity in mouse MLR, while induction of more bulky group for N-17 resulted in significant decrease of the activity. Compound 8 also showed potent cytotoxic activity against DLD-1, Lu-65, A549, K562, and MOLT-4 cells, while the benzyl ester (13) of 1 exhibited potent cytotoxicity against K562, MOLT-4, and jarkat leukemia cell lines. The 17N-acetyl derivative (11) of 1 selectively inhibited the cell growth of DLD-1 cells. The methyl ester (5) of 1 showed potent cytotoxic activity against K562, MOLT-4, and Ball-1 cell lines, the last of which was resistant to 1, 8, and 13.     

Detection of 300-kilodalton membrane protein in adriamycin-resistant human tumor cells by a monoclonal antibody MRK18

To characterize the membrane changes related to adriamycin (ADM) resistance in tumor cells, we have developed monoclonal antibodies against an ADM-resistant subline of human myelogenous leukemia K562 (K562/ADM), and reported the overexpression of P-glycoprotein and 85-kDa protein as determined by the antibodies. In the present study, we have established a monoclonal antibody, MRK18, with higher reactivity to K562/ADM than to K562. MRK18 also showed higher reactivity to other human ADM-resistant lines, 2780AD and Hattori/ADM, than the corresponding parental lines. MRK18 also reacted to human breast cancer MCF-7 and human T-lymphoma CCRF-CEM which have never been exposed to anticancer agents in culture. MRK18 recognized a 300-kDa membrane protein of K562/ADM and MCF-7 and inhibited the growth of these cell lines in culture. These results indicate an induction of the 300-kDa protein during the development of ADM resistance.     

Benzothiazole thiourea derivatives as anticancer agents: Design,synthesis, and biological screening

In a systematic effort to identify a potent anticancer agent, we synthesized benzothiazole thiourea derivatives and examined their cytotoxic activity against five different human and animal cancer cell lines. Benzothiazolylthiocarbamides have been prepared in excellent yields by reaction of substituted 2-amino benzothiazoles with carbon disulfide and dimethyl sulfate followed by their ammonolysis. Cytotoxicity of the four compounds were screened for antitumor activity against human breast cancer cells (MCF-7), human cervix epithelial carcinoma (HeLa), human colon cancer cell line (HT-29), human leukemia cell line (K-562), and mouse neuroblastoma cell line (Neuro-2a) using cisplatin as a reference by MTT assay. Our results presented herein provide experimental evidence that benzothiazolylthiocarbamides induce apoptosis in cancer cell lines. According to flow cytometry results, treatment of HT-29 cells with 1-(6-ethoxy-1,3-benzothiazol- 2-yl)thiourea produced a large population of apoptotic cell (79.45%), which was 1.2-fold higher than that produced by cisplatin (65.28%) at the same concentration.     

Synthesis and hypoxic-cytotoxic activity of some 3-amino-1,2,4-benzotriazine-1,4-dioxide derivatives

A series of 3-amino-1,2,4-benzotriazine-1,4-dioxide derivatives 1 have been synthesized and evaluated for their cytotoxic activity in vitro against human leukemia cell lines: Molt-4, K562, HL60, human liver cancer cell Hep-G2, human prostate cancer cell PC-3 in hypoxia. Most of the compounds showed more potent activity than TPZ. Compounds 1i and 1m displayed encouraging superior activity against Molt-4 and HL-60 cell lines. Three potential derivatives received the test of the activity in hypoxia and in normoxia against Molt-4 and HL-60 cell lines and showed obvious hypoxia selectivity. Further mechanism study revealed that the cytotoxic activities of compounds 1i and 1k in Molt-4 cells might be mediated by modulation of p53 protein expression and mitochondrial membrane potential (DeltaPsi(m)).     

Synthesis, crystal structures, in vitro biological evaluation of zinc(II) and bismuth(III) complexes of 2-acetylpyrazine N(4)-phenylthiosemicarbazone

Two metal complexes formulated as [Zn(L)(2)](2)·H(2)O (1) and [Bi(L)(NO(3))(2)(CH(3)OH)] (2), where HL=2-acetylpyrazine N(4)-phenylthiosemicarbazone, have been synthesized and characterized by elemental analysis, IR, MS, NMR and single-crystal X-ray diffraction studies. Biological studies, carried out in vitro against selected bacteria and the K562 leukemia cell lines, respectively, have shown that the free ligand and its two complexes may be endowed with important biological properties, especially HL with MIC=3.90 μg/mL against Pseudomonas aeruginosa, the zinc(II) complex 1 with IC(50)=1.0 μM against K562 leukemia cell lines, respectively. The compounds HL and 1 may exert their cytotoxicity activity via induced loss of mitochondria membrane potential (MMP).     

Xanthones from Polygala alpestris (Rchb.)

Bioactivity-guided fractionation of Polygala alpestris L. (Rchb.) extracts led to the identification of two new xanthones, 1,3,7-trihydroxy-2,6-dimethoxyxanthone (1) and 2,3-methylenedioxy-4,7-dihydroxyxanthone (2). In addition five known compounds 3,4-dimethoxy-1,7-dihydroxyxanthone (3), 1,3-dihydroxy-7-methoxyxanthone (4), 1,7-dihydroxy-2,3-dimethoxyxanthone (5), 3',6-O-disinapoyl sucrose (6) and 3',5'-dimethoxybiphenyl-4-olo (7) were isolated. The structures of the isolated compounds were established by means of high resolution mass spectrometry, mono- and bi-dimensional NMR spectroscopy. All isolated compounds were tested for cytotoxic activity against three tumor cell lines (LoVo, HL-60, K 562).     

A pair of novel cytotoxic polyprenylated xanthone epimers from gamboges

Two new polyprenylated xanthone epimers were isolated from gamboges of Garcinia hanburyi, and identified by detailed spectroscopic analysis as 30-hydroxygambogic acid (2a) and its (2S)-epimer 30-hydroxyepigambogic acid (2b). Both compounds exhibited significant cytotoxicities against the human leukemia K562/S and the corresponding doxorubicin-resistant K562/R cell lines (Table 2).     

Overexpression of sorcin in multidrug resistant human leukemia cells and its role in regulating cell apoptosis

In an attempt to identify novel proteins involved in the emergence of multidrug resistance (MDR) in leukemia cells, we adopted a proteomics approach to analyze protein expression patterns in leukemia cell lines, K562, and its MDR counterpart, K562/A02. Combining high-resolution two-dimensional gel electrophoresis and mass spectrometry, we compared the protein expression profiles between K562 and K562/A02. A total number of 22 protein spots with altered abundances of more than 2-fold were detected and 14 proteins were successfully identified. Consistent with our previous observations by cDNA microarray, sorcin, a 22-kDa calcium-binding protein, was also identified by this proteomic approach with a 10.4-fold up-regulation in K562/A02 cells. Overexpression of sorcin protein in K562 cells by gene transfection led to significantly reduced cytosolic calcium level and increased resistance to cell apoptosis. Further, leukemia cell lines over-expressing sorcin also showed up-regulation of Bcl-2, along with decreased level of Bax. Taken together, our results suggest that sorcin plays an important role in the emergence of MDR in leukemia cells via regulating cell apoptosis pathways, thus may represent both a new MDR marker for prognosis and a good target for anti-MDR drug development.     

Effects of theanine on growth of human lung cancer and leukemia cells as well as migration and invasion of human lung cancer cells

The aim of this study is to investigate the effects of theanine, a tea characteristic amino acid, on human lung cancer and leukemia cells. In the present study, we have demonstrated that theanine suppressed the in vitro and ex vivo growth of human non-small cell lung cancer A549 and leukemia K562 cell lines in dose- and time-dependant manners. In addition, theanine displayed the inhibitory effect on the migration of A549 cells. More importantly, theanine enhanced the anticancer activity of anticancer agents such as trichostatin A (the histone deacetylase inhibitor), berbamine and norcantharidin (the anticancer drugs in China) by strongly reducing the viability and/or migration rate in A549 cells. In addition, theanine significantly suppressed A549 cell invasion. Suppression of A549 cell migration may be one of the important mechanisms of action of theanine against the A549 cell invasion. Our present results suggest that theanine may have the wide therapeutic and/or adjuvant therapeutic application in the treatment of human lung cancer and leukemia.     

α-Tomatine-Mediated Anti-Cancer Activity In Vitro and In Vivo through Cell Cycle- and Caspase-Independent Pathways

α-Tomatine, a tomato glycoalkaloid, has been reported to possess antibiotic properties against human pathogens. However, the mechanism of its action against leukemia remains unclear. In this study, the therapeutic potential of α-tomatine against leukemic cells was evaluated in vitro and in vivo. Cell viability experiments showed that α-tomatine had significant cytotoxic effects on the human leukemia cancer cell lines HL60 and K562, and the cells were found to be in the Annexin V-positive/propidium iodide-negative phase of cell death. In addition, α-tomatine induced both HL60 and K562 cell apoptosis in a cell cycle- and caspase-independent manner. α-Tomatine exposure led to a loss of the mitochrondrial membrane potential, and this finding was consistent with that observed on activation of the Bak and Mcl-1 short form (Mcl-1s) proteins. Exposure to α-tomatine also triggered the release of the apoptosis-inducing factor (AIF) from the mitochondria into the nucleus and down-regulated survivin expression. Furthermore, α-tomatine significantly inhibited HL60 xenograft tumor growth without causing loss of body weight in severe combined immunodeficiency (SCID) mice. Immunohistochemical test showed that the reduced tumor growth in the α-tomatine-treated mice was a result of increased apoptosis, which was associated with increased translocation of AIF in the nucleus and decreased survivin expression ex vivo. These results suggest that α-tomatine may be a candidate for leukemia treatment.     

Synthesis and Evaluation of Novel Isoindoline-1,3-dione Derivatives as Anticancer Agents

Russian Journal of Bioorganic Chemistry - N-Substituted imides, isoindoline-1,3-dione derivatives, were synthesized, characterized, and investigated against blood cancer using K562 and Raji cell...     

动物源杂合肽P18对白血病K562细胞的致死作用研究

通过其致死白血病K562细胞过程,对动物源杂合肽P18的分子结构与功能进行了研究.MTT实验表明P18显著致死K562细胞;Western blot实验和流式细胞分析提示P18导致 K562细胞坏死,而非依赖于caspases的传统凋亡;荧光探针标记后,观察到P18显著增加K562细胞的膜通透性;圆二(CD)图谱分析,在模拟细胞膜环境的溶液中,P18分子出现α-螺旋.综上所述,P18肽分子可能在细胞膜微环境的介导下产生α-螺旋,产生或暴露了肽分子的破膜结构,导致膜通透性显著增加,最终导致K562细胞的坏死.     

Synthesis, characterization, electrochemical studies and antitumor activity of some new chalcone analogues containing ferrocenyl pyrazole moiety

A series of new α,β-unsaturated conjugated ketones containing ferrocenyl pyrazole unit were synthesized and fully characterized by IR and NMR spectroscopy. Electrochemical characterization of subject compounds was performed by means of cyclic voltametry. The in vitro cytotoxic activity of all the synthesized compounds was studied against cervix adenocarcinoma HeLa, melanoma Fem-x and myelogenous leukemia K562 cell lines by the MTT method. Derivative 1l containing 3-pyridyl moiety exhibited a better cytotoxic activity in the cell growth inhibition of K562 cell lines in comparison with cisplatin as a reference compound.     

Thymosin alpha1 suppresses proliferation and induces apoptosis in human leukemia cell lines

Thymosin alpha1 (Talpha1), a 28-amino acid peptide, is a well-known immune system enhancer for the treatment of various diseases. In the present investigation, the effects of Talpha1 on the proliferation and apoptosis of human leukemia cell lines (HL-60, K562 and K562/ADM) were studied. The proliferation was significantly depressed after 96 h of treatment with Talpha1, and obvious signs of apoptosis, i.e., cell morphology, nuclei condensation and Annexin V binding, were observed thereafter. Moreover, the up-regulation of Fas/Apol (CD95) and decrease in bcl-2 anti-apoptotic gene expression were observed in apoptotic cells. The expression and the function of P-glycoprotein (P-gp) can be slightly inhibited by Talpha1. It is noteworthy that K562 and K562/ADM were more sensitive than HL-60 cells when subjected to Talpha1. Furthermore, HepG-2, the human hepatoma cell line, displayed significant less sensitivity to Talpha1 than all the human leukemia cell lines. D-Tubocurarine (TUB), a nicotinic acetylcholine receptors (nAChRs) antagonist, significantly antagonized the inhibition effects induced by Talpha1, whereas atropine, a muscarinic acetylcholine receptor antagonist, did not exhibit such effects. All the results indicate that Talpha1 was able to significantly suppress proliferation and induce apoptosis in human leukemia cell lines.     

Natural killer (NK)-resistant human lung cancer cells are lysed by recombinant interleukin-2-activated NK cells

Natural killer (NK) cells are active in host defence against tumors. In order to determine if NK cells have the capacity to lyse human lung cancer cells, we evaluated blood NK cell activity against human lung carcinoma lines representing each of the commonest histological types of lung cancer, NCI-H157 (large cell), LICM107 and NCI-H146 (small cell), NCI-H226 (squamous cell), and LICM26 (adeno), and compared the results to their activity against a standard NK-sensitive target, K562, using a 16-hr 51Cr-release assay. At effector to target (E:T) ratios up to 50:1, NK activity was very low against each of the lung cancer cell lines compared to the K562 cells (NCI-H157 10 +/- 2%, LICM107 12 +/- 2%, NCI-H146 14 +/- 5%, NCI-H226 8 +/- 5%, and LICM26 7 +/- 3%, compared to K562 60 +/- 3%, P less than 0.001, for each compared to K562 cells). Recombinant interleukin 2 (IL-2) produced a dose-dependent augmentation of NK activity against each of the lung cancer cell lines, with doses as low as 0.25 U/ml being effective. The highest level of boosting was seen against NCI-H157 cells where NK activity (E:T, 50:1, IL-2, 250 U/ml) increased from 9 +/- 2 to 56 +/- 7%, P less than 0.001). Only brief exposure to IL-2 was necessary for augmentation to occur, with as little as 5 min being required for activation, although increased exposure times produced increased levels of augmentation. NK cells appeared to be the IL-2-responsive lytic cell population in these experiments as Leu 11b-depleted lymphocytes expressed little IL-2-mediated augmentation of activity against these target cells, and most of this IL-2-mediated augmentation of activity was located in the large granular lymphocyte-enriched fraction of the lymphocyte population. We conclude that normal blood NK cell activity against human lung cancer cell lines is low but that this activity can be markedly augmented by brief exposure of NK cells to low doses of recombinant IL-2, suggesting a potential role for IL-2 in the immunotherapy of human lung cancer.     

Modulation of natural cytotoxicity by alloantibodies. I. Alloantisera enhancement of cytotoxicity of mouse spleen cells toward a human myeloid cell line.

Natural killer activity of spleen cells obtained from different strains of mice against the human myeloid leukemia cell line, K562, and two mouse cell lines P815 and L1210 was measured by using the 4-hr chromium release assay. The level of cytotoxic activity of spleen cells against the K562 target was usually less than 4% lysis. However, treatment of the spleen cells with a specific anti-H-2 antiserum resulted in a dose-dependent augmentation of the degree of lysis of K562 cells. The augmentation of cytotoxic activity could be obtained by pretreatment of the spleen cells with antisera or by directly adding the antisera to the cytotox-incubation medium. Anti-thy-1 and anti-immunoglobulin antisera had no enhancing effect under similar conditions. The specific alloantisera-treated spleen cells did not show any increase in cytotoxicity against P815 and L1210 target cells. Spleen cells responsible for the alloantiserum-mediated augmentation of cytotoxicity against K562 cells appear to be different from T or B cells as indicated by their resistance to anti-thy-1 and complement treatment and lack of adherence to nylon wool columns.     

New gemacranolides from Eupatorium hualienense

Phytochemical investigation of Eupatorium hualienense (C. H. Ou, S. W. Chung, C. I. Peng) has resulted in the isolation of the new sesquiterpene lactones 1-5, named eupahualins A-E, along with the known heliangolide eupasimplicin B (6). The structures of the isolated compounds were established through detailed spectral analyses, especially by means of 2D-NMR techniques. Compounds 1-4 and 6 showed significant activities against cell lines of human chronic myelogenous leukemia (K562) and human bone cancer (U2OS).     

Design, synthesis, and in vitro antiproliferative activity of novel Dasatinib derivatives

Two series of novel Dasatinib derivatives have been designed and synthesized, with their in vitro cytostatic effect screened on human chronic myeloid leukemia cell line K562 and human myeloid leukemia cell line U937. Some target compounds demonstrated significant inhibitory activities against both cell lines. Compared to the contrast drug Dasatinib, 1b, 1c, 1d, 1e and 1f were found to demonstrate more potent antitumor activities. The structures of all the newly synthesized compounds were determined by (1)H NMR and (13)C NMR.     

Externalization and binding of galectin-1 on cell surface of K562 cells upon erythroid differentiation

Galectin 1 (GAL1) is a β-galactoside-binding lectin involvedin cell cycle progression. GAL1 overexpression is associatedwith neoplastic transformation and loss of differentiation.The gene encoding for human GAL1 resides on chromosome 22(ql2;ql3), and its expression is devel-opmentally regulated. Althoughdevoid of signal peptide GAL1 can be externalized from cellsby a mechanism independent of the normal secretory process.We report here on a study of the effects of erythroid differentiationof the human leukemia cell line K562 on GAL1 protein expression.In undifferentiated K562 cells, GAL1 was expressed into thecytosol. However, the amount of GAL1 was surprisingly weakerin K562 cells than in other leukemia cell lines such as TF-1or KGla. Treatment of K562 cells with erythropoietin (EPO) orwith aphidicolin (APH), an inhibitor for DNA polymerase , inducedan erythroid pheno-type and led to the externalization of cytosolicGAL1 which was then bound to ligands on cell surface in a galactoside-inhibitablefashion. Our results demonstrate that acquisition of an erythroidphenotype is associated with an exter-nalization of GALL Theautocrine binding of GAL1 to cell surface ligands of non adherentcells such as K562 suggest that GAL1 is implicated rather insignal transduction than in cell-cell or cell-matrix interaction.Moreover, the reciprocal translocation involving chromosomes9 and 221(9;22) present in K562 cells might explain the weakexpression of GAL1 in K562 leukemia cells. galectin-l K562 cells differentiation glycoconjugates