L1210 Murine Leukemia Cells Research Articles

Autophagic and Apoptotic Response to Sonodynamic Therapy Induced Cell Damage in Leukemia L1210 CellsIn Vitro

The present study was initiated to study the autophagic and apoptotic response to sonodynamic therapy (SDT) in murine leukemia L1210 cells in vitro. L1210 cells were examined after 6 hours of incubation following SDT induction with ultrasound at a frequency of 1.1 MHz and an intensity of 3 W/cm(2) in the presence of 1 μg/mL protoporphyrin IX. Apoptosis rate and cell survival rate were assessed through double fluorescent staining with Annexin V-PE and 7-amino-actinomycin D as determined by flow cytometry. Transmission electron microscope and fluorescence microscope were used to identify the formation of acidic vesicular organelles (autophagic vacuoles) during autophagy. Western blots were used to examine the processing of light chain 3 (LC3)-I to LC3-II and Atg5 expression levels. This study showed that SDT treatment reduced the numbers of viable cells to 30.17% and enhanced the apoptotic cells to 19.37% (p < 0.05 compare with control). Additionally, autophagic vacuoles formation clearly occurred after SDT and simultaneously accompanied by obvious LC3 processing and increased Atg5 expression levels. In L1210 cells, both apoptosis and autophagy were involved in cell damage induced by SDT treatment at the experimental conditions.

Pyrinodemins E and F, new 3-alkylpyridine alkaloids from sponge Amphimedon sp.

Two new 3-alkylpyridine alkaloids, pyrinodemins E (1) and F (2), were isolated from an Okinawan marine sponge Amphimedon sp. and the structures of 1 and 2 were elucidated on the basis of spectroscopic data. Pyrinodemins E (1) and F (2) were novel 3-alkylpyridine alkaloids possessing a 4-(methoxyamino)piperidinone moiety and an indol-3-glyoxylamide moiety, respectively. Pyrinodemin E (1) showed cytotoxicity against P388 and L1210 murine leukemia cells.

Synthesis and cytostatic evaluation of some 2-(5-substituted-2-oxoindolin-3-ylidene)-N-substituted hydrazine carbothioamide

Various substituted 2-(5-substituted-2-oxoindolin-3-ylidene)-N-substituted hydrazine carbothioamide 4a–g and 2-(5-substituted-1-(4-substituted benzyl)-2-oxoindolin-3-ylidene)-N-substituted hydrazine carbothioamide 5a–k were synthesized. The compounds were evaluated for their cytostatic activity against human Molt4/C8 and CEM T-lymphocytes as well as murine L1210 leukemia cells. Several of these compounds were endowed with low micromolar 50%-inhibitory concentration (IC50) values, and some were virtually equally potent as melphalan. The most potent inhibitors against the murine leukemia cells were also most inhibitory against human T-lymphocyte tumor cells. 2-(5-fluoro-1-(4-fluorobenzyl)-2-oxoindolin-3-ylidene)-N-p-tolylhydrazine carbothioamide (5b) emerged as the most potent cytostatic compound among the tested compounds. The encouraging cytostatic data provide an adequate rationale for further modification of these molecular scaffolds.

Photochemical and phototoxic properties of ethyl 1,4-dihydro-8-nitro-4-oxoquinoline-3-carboxylate, a new quinoline derivative

The present study demonstrates photoinduced generation of superoxide radical anion and singlet oxygen upon UVA irradiation of ethyl 1,4-dihydro-8-nitro-4-oxoquinoline-3-carboxylate ( DNQC), and its cytotoxic/phototoxic effects on murine leukemia L1210 cells. The formation of reactive oxygen species (ROS) was investigated by EPR spectroscopy using in situ spin trapping technique and 4-hydroxy-2,2,6,6-piperidine (TMP) for singlet oxygen ( 1O 2) detection. The EPR spectra monitored upon photoexcitation of aerated solutions of DNQC in dimethylsulfoxide evidenced the efficient activation of molecular oxygen via Types I and II mechanisms. The cytotoxic/phototoxic effects of DNQC, analysis of cell cycle, induction of apoptosis/necrosis, DNA damage and molecular mechanism of apoptotic death of L1210 cells in dark and in the presence of UVA irradiation were compared. DNQC induced a different cytotoxic/phototoxic effect, which was concentration- and time-dependent. The four highest tested concentrations of non-photoactivated and photoactivated DNQC induced immediate cytotoxic/phototoxic effect after 24 h cultivation of L1210 cells. This effect decreased with the time of treatment. The irradiation increased the sensitivity of leukemia cell line on DNQC, but the cell sensitivity decreased with time of processing. Quinolone derivative DNQC significantly induced direct DNA strand breaks in L1210 cells, which were increased with the irradiation of cells. The DNA damage generated by DNQC alone/with combination of UVA irradiation induced cell arrest in G 0/G 1 and G 2/M phases, decrease in the number of L1210 cells in S phase and apoptotic cell death of certain part of cell population after 24 h of influence. DNQC alone/with combination of UVA irradiation induced apoptosis in L1210 cells through ROS-dependent mitochondrial pathway.

Synthesis, biological evaluation and docking studies of 4-amino-tetrahydroquinazolino[3,2- e]purine derivatives

The synthesis of new 4-amino-tetrahydroquinazolino[3,2- e]purine derivatives along with their activity in cell-free enzymatic assays on Src is reported. Some compounds emerged as moderately active inhibitors of the enzyme and showed antiproliferative effects on the murine leukemia L1210 cell line. Docking studies have been also performed to analyze the binding mode of compounds under study and to identify the structural determinants of their interaction. Therefore, this study provides a new promising scaffold with moderate enzymatic inhibitory activities for further development of new anticancer drugs targeting Src tyrosine kinase.

Induction of apoptosis and cell cycle arrest in L-1210 murine lymphoblastic leukaemia cells by (2E)-3-(2-naphthyl)-1-(3′-methoxy-4′-hydroxy-phenyl)-2-propen-1-one

New compounds with biological targets and less cytotoxicity to normal cells are necessary for cancer therapy. In this work ten synthetic chalcones derived from 2-naphtaldehyde were evaluated for their cytotoxic effect in murine acute lymphoblastic leukemia cells L-1210. A series of ten chalcones derived from 2-naphtaldehyde and corresponding acetophenones were prepared by aldolic condensation, using methanol as solvent under basic conditions, at room temperature for 24 h. The cell viability was determined by MTT colorimeter method. The cell cycle phase analysis was carried out by flow cytometry after propidium iodide staining. The apoptosis induction was assessed by exposure to phosphatidylserine (ANNEXIN V-FITC). Cytometric analysis was performed to evaluate the expression of p53, Bcl-2 and Bax protein. The caspase-3 expression was studied by immunoblotting analysis. A preliminary screening of a series of ten chalcones derived from 2-naphtaldehyde showed that chalcone 8, (2E)-3-(2-naphtyl)-1-(3'-methoxy-4'-hydroxy-phenyl)-2-propen-1-one, had the highest cytotoxic effect (IC50 of 54 microM), but not in normal human lymphocytes. To better understand the cytotoxic mechanism of chalcone 8, its effect on cell cycle and apoptosis was assessed. Our results showed that chalcone 8 caused cell cycle arrest in the G2/M phase and a significant increase in the proportion of cells in the subG0/G1 phase. Our results also demonstrated that chalcone 8 promoted a modification in Bax:Bcl-2 ratio and increased p53 expression and caspase-3 activation. The studied chalcone 8 has cytotoxic effect against L-1210 lymphoblastic leukaemic cells, and this effect is associated with increase of p-53 and Bax expression.

Synthesis and Evaluation of Haloacetyl, &amp;#945;-Bromoacryloyl and Nitrooxyacetyl Benzo[b]furan and Benzo[b]thiophene Derivatives as Potent Antiproliferative Agents Against Leukemia L1210 and K562 Cells

Identification of novel and selective anticancer agents remains an important and challenging goal in pharmacological research. In search of new compounds with strong antiproliferative activity and simple molecular structure, we have synthesized three different series of compounds in which different substituents were linked to the 3-amino position of the 2-(3', 4', 5'-trimethoxybenzoyl)-benzo[b]furan or benzo[b]thiophene ring system. These substituents, corresponding to acetyl/haloacetyl, α-bromoacryloyl and nitrooxyacetyl moieties had different electrophilic properties. The benzoheterocycle parent structures were selected because of their reported bioactivities. Compounds bearing a methoxy group at the 6-position of the benzo[b]furan skeleton, were identified as potent antiproliferative agents against the human chronic myelogenous K562 and murine L1210 leukemia cell lines. Comparison of positional isomers indicated that moving the methoxy group from the 6- to the 5- or 7-position yielded inactive compounds. The effects of a selected series of compounds on cell cycle progression correlated well with their strong antiproliferative activity and inhibition of tubulin polymerization. The analysis of structure-activity relationships observed in the series of compounds described here may represent a platform for the design of more active molecules.

The anti-invasive activity of synthetic alkaloid ethoxyfagaronine on L1210 leukemia cells is mediated by down-regulation of plasminogen activators and MT1-MMP expression and activity

Quaternary benzo[c]phenanthridines such as fagaronine are natural substances which have been reported to exhibit anticancer and anti-leukemic properties. However, the therapeutic use of these molecules is limited due to the high dose required to exhibit anti-tumor activity and subsequent toxicity. In this study, we describe the therapeutic potential of a new derivative of fagaronine, Ethoxyfagaronine (N-methyl-12-ethoxy-2hydroxy-3, 8, 9-trimethoxybenzo[c]-phenanthridiniumchlorhydrate) as an anti-leukemic agent. Cytotoxic activity and cell growth inhibition of Ethoxyfagaronine (Etxfag) was tested on murine L1210 leukemia cells using trypan blue assay and MTT assay. At the concentration of 10(-7) M, Etxfag induced less than 10% of cell death. Etxfag (10(-7) M) was tested on L1210 cell invasiveness using matrigel™ precoated transwell chambers and efficiently reduces the invasive potential of L1210 cells by more than 50% as compared with untreated cells. Western blot and immunofluorescence experiments showed that Etxfag decreased both MT1-MMP expression and activation at the cell surface, decreased plasmin activity by down-regulating u-PAR and uPA expression at the cell surface and increasing PAI-1 secretion in conditioned media. The set of our findings underscore the therapeutic potential of ethoxyfagaronine as a new potential anticancer agent able to prevent leukemic cell dissemination.

Synthesis, Antitumor Evaluation and Crystal Structure of Hydroxyurea Derivatives

A series of hydroxyurea derivatives have been synthesized and elucidated by means of FT-IR, (1)H-, (13)C-NMR and MS. The exact stereostructures of representative compounds have been determined by X-ray crystal structure analysis. In the crystals, inversion dimers linked by pairs of N-H...O hydrogen bonds occurred, and further N-H...O links led to chains of molecules. In vitro antitumor activities against Tca8113 human tongue cancer cells and L1210 murine leukemia cells were evaluated. A total of 8 of the 12 compounds had higher inhibitory activities than hydroxyurea against L1210 cells. Among them, the most promising compounds were 3e, 3d, 3a and 2d.

3,5‐Bis(benzylidene)‐4‐oxo‐1‐phosphonopiperidines and Related Diethyl Esters: Potent Cytotoxins with Multi‐Drug‐Resistance Reverting Properties

A series of 3,5-bis(benzylidene)-4-piperidones 3 were converted into the corresponding 3,5-bis(benzylidene)-1-phosphono-4-piperidones 5 via diethyl esters 4. The analogues in series 4 and 5 displayed marked growth inhibitory properties toward human Molt 4/C8 and CEM T-lymphocytes as well as murine leukemia L1210 cells. In general, the N-phosphono compounds 5, which are more hydrophilic than the analogues in series 3 and 4, were the most potent cluster of cytotoxins, and, in particular, 3,5-bis-(2-nitrobenzylidene)-1-phosphono-4-piperidone 5 g had an average IC(50) value of 34 nM toward the two T-lymphocyte cell lines. Four of the compounds displayed potent cytotoxicity toward a panel of nearly 60 human tumor cell lines, and nanomolar IC(50) values were observed in a number of cases. The mode of action of 5 g includes the induction of apoptosis and inhibition of cellular respiration. Most of the members of series 4 as well as several analogues in series 5 are potent multi-drug resistance (MDR) reverting compounds. Various correlations were noted between certain molecular features of series 4 and 5 and cytotoxic properties, affording some guidelines in expanding this study.

Synthesis and cytotoxicity of 1-phenylethanolamine carboxamide derivatives: effects on the cell cycle

Seven novel analogues of 1-phenylethanolamine carboxamide derivatives, 3a–3g, related to carboxamides isolated from Isodon excisus were synthesized and evaluated for their cytotoxic and apoptosis-induction properties against murine B16 and leukemia L1210 cell lines. Compounds containing no substitution at the 4′-position (3a–3d) or containing a 4′-amino (3e–3g) group were investigated. Generally, the amino-containing compounds were slightly more active than their unsubstituted congeners. Also, the indole-containing compounds 3c and 3f gave the strongest cytotoxic activity (IC50 = 25–87 μM) against the growth of L1210 and B16 cancer cells. Compound 3f was subjected to flow cytometry studies and it was found to induce L1210 cells grown in culture to undergo apoptosis.

Effects of extracellular purines on cytotoxicity of methotrexate

Nucleoside and base modulation of the cytotoxicity of nucleic acid and folate antimetabolite drugs has been widely discussed. Many investigators have observed reduced toxicity due to circumvention of drug-induced inhibition of de novo purine and pyrimidine synthesis. However, exogenous purine nucleosides and bases may also enhance the cytotoxicity of even moderate concentrations of antifolate drugs (MTX and PTX) which inhibit dihydrofolate reductase. In this study, the effects of nucleosides in the medium on the cytotoxicity and deoxyribonucleoside triphosphate pools after brief exposure of cultured cells to methotrexate have been studied in cultured L1210 murine leukaemia cells. Cell viability was determined by trypan blue exclusion assay. Colony formation was assessed by microtitration cloning assay. The deoxyribonucleotides were measured by a modification of the DNA polymerase assay. Purines were extracted with trioctylamine and 1,1,2-trichlorotrifluoroethane buffer and concentrations of purine bases were determined by HPLC. Subculture of drug-treated cells in fresh medium containing 10% FCS led to greater toxicity than sub culture in 'conditioned' medium, i.e. fresh medium in which logarithmically growing cells had been cultured for 24 h before separation. Cells resuspended in fresh medium had increased dATP and sustained inhibition of dTTP levels, while cells subcultured in 'conditioned' medium had no elevation of dATP. Hypoxanthine concentration determined by HPLC in 'conditioned' medium was 0.9 microM compared to 6.7 microM in fresh medium. Resuspension of drug-treated cells in conditioned medium supplemented with 10 or 100 microM HX enhanced cytotoxicity and increased the dATP levels. These results add further evidence that purines present in normal culture conditions are important determinants of methotrexate cytotoxicity. Elevation of dATP levels after methotrexate treatment is an important modulator of cytotoxicity.

Design, synthesis and bioevaluation of novel maleamic amino acid ester conjugates of 3,5-bisarylmethylene-4-piperidones as cytostatic agents

A novel series of maleamic amino acid ester conjugates of 3,5-bisarylmethylene-4-piperidones were prepared to investigate the efficacy of micronutrient conjugation in enhancing cytotoxic potency by improving selectivity and delivery. These compounds, prepared as anticancer agents, were expected to demonstrate enhanced selectivity towards malignant cells through the inhibition of topoisomerase IIα via protein thiolation. The cytostatic effects of these compounds were evaluated against three cell lines, namely murine L1210 leukemia cells, human Molt 4/C8 and CEM T-lymphocyte cells. All compounds were found to have greater potency than the reference drug melphalan. Several compounds were found to potently inhibit topoisomerase IIα and displayed cytostatic activity in the nanomolar range.

Lissoclibadins 8–14, polysulfur dopamine-derived alkaloids from the colonial ascidian Lissoclinum cf. badium

Seven new polysulfur alkaloids, lissoclibadins 8 ( 1)–14 ( 7), were isolated from an ascidian, Lissoclinum cf. badium, collected in Indonesia. The structures were assigned on the basis of their spectroscopic data and computational modeling study. Lissoclibadin 8 ( 1) had four identical dopamine-derived units, and this is the first instance of a tetramer. Lissoclibadin 9 ( 2) was the second example of trimers next to lissoclibadin 1 ( 8). Lissoclibadins 10 ( 3)–12 ( 5) were symmetric dimers, and 13 ( 6) had a dopamine and ethyl units connected by sulfide and disulfide bonds. Lissoclibadin 14 ( 7) was a varacin-type monomer. These compounds inhibited the colony formation of Chinese hamster V79 cells and cell proliferation of murine leukemia L1210 cells.

3-(5-Nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline induces ROS-mitochondrial mediated death signaling and activation of p38 MAPK in murine L1210 leukemia cells

Quinazoline derivatives are multitarget agents with a broad spectrum of biological activity. 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline (NTCHMTQ) is a new synthetically prepared derivative, which in our previous studies showed antiproliferative and apoptosis inducing activities towards murine L1210 leukemia cells. The aim of this study was to provide the insight into the molecular mechanism regulating NTCHMTQ-induced apoptosis in L1210 cells. The activity of caspases 3, 8 and 9, generation of reactive oxygen species (ROS), mitochondrial membrane potential changes, release of cytochrome c, degradation of PARP and activation of c-Jun N-terminal kinase 1/2 (JNK1/2), p38 MAPK and extracellular-regulated kinase 1/2 (ERK1/2) were investigated. NTCHMTQ induced production of ROS, activation of caspases 3 and 9, cytochrome c release, PARP cleavage and activation of p38 MAPK, with no activation of JNK1/2 and ERK1/2. Our resuls clearly demonstrate that NTCHMTQ induces apoptosis of L1210 leukemia cells through ROS-mitochondrial mediated death signaling and activation of p38 MAPK.

Synthesis, anticancer and cytostatic activity of some 6H-indolo[2,3-b]quinoxalines

Various 6-aralkyl-9-substituted-6H-indolo[2,3-b]quinoxalines were synthesized by reaction of 1,5-disubstituted 2,3-dioxo-2,3-dihydroindole and orthophenylene diamine. Appreciable anticancer activity of compounds 5b, 5d, 5g and 5l at various cell lines among 59 human tumor cell panels was observed. All the synthesized compounds were evaluated for cytostatic activity against human Molt 4/C8 and CEM T-lymphocytes as well as for murine L1210 leukemia cells. Compound 5h exhibited an I C50 of 23 micromol L(-1) against Molt 4/C8 and 38 micromol L(-1) against CEM compared to melphalan 3.2 micromol L(-1) and 2.5 micromol L(-1), respectively. The IC(50) for compound 7i against L1210 was 7.2 micromol L(-1) compared to melphalan 2.1 micromol L(-1).

1-Arylmethyl-2,3-dioxo-2,3-dihydroindole thiosemicarbazones as leads for developing cytotoxins and anticonvulsants

Various substituted 1-arylmethyl-2,3-dioxo-2,3-dihydroindole thiosemicarbazones 3a-h, 1-benzyl-2,3-dioxo-2,3-dihydroindole N4-aryl thiosemicarbazones 4a-i and 1-benzyl-2,3-dioxy-2,3-dihydroindole N4-cyclohexylthiocarbazone 5 were synthesized. All of these compounds were evaluated against human Molt 4/C8 and CEM T-lymphocytes as well as murine L1210 leukemia cells. Nearly 40% of these compounds possess low micromolar IC50 values and some are either more potent than, or equipotent with, melphalan. Various correlations between the structures of these compounds and cytotoxic potencies were obtained which included the use of QSAR and molecular modeling techniques. Representative compounds displayed anticonvulsant properties in rats and were well tolerated by these animals. The encouraging biodata noted affords adequate rationale for outlining guidelines for further development of these molecular scaffolds.

4‐Amino‐3‐acetylquinoline‐induced apoptosis of murine L1210 leukemia cells involves ROS‐mitochondrial‐mediated death signaling and activation of p38 MAPK

Quinolines are known to be multitarget agents with a broad spectrum of biological activity. In a previous study, we showed that newly prepared 4-amino-3-acetylquinoline (AAQ) possesses strong anticancer activities. In this study, we investigated whether AAQ has cytotoxicity in murine L1210 leukemia cells. Results from cell proliferation assays showed that AAQ caused significant decrease in cell number in a dose-dependent manner. The cell death induced by AAQ appeared to involve apoptosis, based on evidence from apoptotic DNA fragmentation, flow cytometry, fluorescence microscopy, and Western blot analyses. We found that AAQ-treated cells had activated p38 MAPK and that apoptosis was processed through a reactive oxygen species (ROS)-dependent mitochondrial pathway. In summary, our results suggest that AAQ can induce apoptosis, at least in part, through the activation of the p38 MAPK pathway in L1210 leukemia cells.

H2S and HS− donor NaHS releases nitric oxide from nitrosothiols, metal nitrosyl complex, brain homogenate and murine L1210 leukaemia cells

Nitrosoglutathione [(GSNO), 500 nmol/l] relaxed the norepinephrine precontracted rat aortic rings. The relaxation effect was pronouncedly enhanced by H(2)S- and HS(-)-donor NaHS (30 micromol/l) at 7.5 pH but not at 6.3 pH. To study molecular mechanism of this effect, we investigated whether NaHS can release NO from NO donors. Using an electron paramagnetic resonance spectroscopy method of spin trap and by measuring the NO oxidation product, which is nitrite, by the Griess reaction, we report that NaHS released NO from nitrosothiols, namely from GSNO, S-nitroso-N-acetyl-DL: -penicillamine (SNAP), from metal nitrosyl complex nitroprusside (SNP) and from rat brain homogenate and murine L1210 leukaemia cells. From the observation that the releasing effect was more pronounced at 8.0 pH than 6.0 pH, we suppose that HS(-), rather than H(2)S, is responsible for the NO-releasing effect. Since in mammals, H(2)S and HS(-) are produced endogenously, we assume that their effect to release NO from nitrosothiols and from metal nitrosyl complexes are responsible for some of their biological activities and that this mechanism may be involved in S-nitrosothiol-signalling reactions.

AMID: new insights on its intracellular localization and expression at apoptosis

AMID (apoptosis-inducing factor (AIF)-like mitochondrion-associated inducer of death) is a poorly studied member of the AIF family; despite the given name AMID, predicting its association with mitochondria, its real cellular localization, as well as its role and changes during apoptosis are currently unclear. By means of MALDI-TOF mass spectrometry, we have identified as AMID (accession number AAH38129, sequence coverage 31%) the protein isolated by Pisum sativum lectin-affinity chromatography from the plasma membrane fraction of apoptotic murine leukemia L1210 cells, lacking in the intact cells. The obtained results suggest its possible glycosylation that was further suggested by finding N-glycosylation sequon in the signal peptide of AMID protein (in silica), and by predicting transmembrane localization of its N-terminal part. Using monoclonal antibodies to AMID, we demonstrated an increased expression of AMID in human leukemia Jurkat T-cells after apoptosis induction. Immunocytochemical study suggested its association to the plasma membrane.