Human Chronic Myelogenous Leukemia K562 Research Articles

A label free chemoproteomic-based platform to disclose cannabidiol molecular mechanism of action on chronic myelogenous leukemia cancer cells

The discovery of the interactome of cannabidiol (CBD), a non-psychoactive cannabinoid from Cannabis sativa L., has been here performed on chronic myelogenous leukemia cancer cells, using an optimized chemo-proteomic stage, which links Drug Affinity Responsive Target Stability with Limited Proteolysis Multiple Reaction Monitoring approaches. The obtained results showed the ability of CBD to target simultaneously some potential protein partners, corroborating its well-known poly-pharmacology activity. In human chronic myelogenous leukemia K562 cancer cells, the most fascinating protein partner was identified as the 116 kDa U5 small nuclear ribonucleoprotein element called EFTUD2, which fits with the spliceosome complex. The binding mode of this oncogenic protein with CBD was clarified using mass spectrometry-based and in silico analysis.

Metal Complexes of Schiff Bases Prepared from Quinoline-3-Carbohydrazide with 2-Nitrobenzaldehyde, 2-Chlorobenzaldehyde and 2,4-Dihydroxybenzaldehyde: Structure and Biological Activity

Three Schiff base ligands, NQ, CQ and HQ, were prepared from the reaction of quinoline-3-carbohydrazide with 2-nitrobenzaldehyde, 2-chlorobenzaldehyde and 2,4-dihydroxybenzaldehyde, respectively, and were investigated for their coordination to Cu (II), Ni(II), Co(II), Cd(II), Cr(III) and Fe(III) chlorides. The NQ preparation and the X-ray structure of NQ and CQ, as well as the transition metal complexes of NQ, CQ and HQ, were reported for the first time. FTIR, 1H-NMR, magnetic susceptibility and elemental analysis were used to study the coordination of ligands to the metal ions. Based on the magnetic susceptibility and elemental analysis results, octahedral structures of the complexes such as [CuL2Cl(OH)], [FeL2Cl2(OH)] and [CoL2Cl(OH)] were proposed for L = NQ, CQ and HQ. The relatively large Cd(II) exhibited [CdL3(OH)2]. The FTIR study revealed that NQ and CQ are coordinated to the metal ions via azomethine nitrogen and carbonyl oxygen while HQ through azomethine nitrogen and phenolic oxygen. Despite the high solvation power of DMSO solvent in 1H-NMR experiments, the azomethine HC=N peak at 9.3 ppm is the most affected by complexation with metal ions. On the other hand, quinoline nitrogen seems to be a weaker coordinating site than the azomethine nitrogen. The HQ ligand, containing phenolic groups, and its complexes with Cu and Ni were found to have inhibitory effects on human breast adenocarcinoma MCF-7 and human chronic myelogenous leukemia K562. Nevertheless, metal ions did not exhibit a significant synergistic effect on the antiproliferative activity of the ligands investigated.

Profiling the polyadenylated transcriptome of extracellular vesicles with long-read nanopore sequencing

BackgroundWhile numerous studies have described the transcriptomes of extracellular vesicles (EVs) in different cellular contexts, these efforts have typically relied on sequencing methods requiring RNA fragmentation, which limits interpretations on the integrity and isoform diversity of EV-targeted RNA populations. It has been assumed that mRNA signatures in EVs are likely to be fragmentation products of the cellular mRNA material, and the extent to which full-length mRNAs are present within EVs remains to be clarified.ResultsUsing long-read nanopore RNA sequencing, we sought to characterize the full-length polyadenylated (poly-A) transcriptome of EVs released by human chronic myelogenous leukemia K562 cells. We detected 443 and 280 RNAs that were respectively enriched or depleted in EVs. EV-enriched poly-A transcripts consist of a variety of biotypes, including mRNAs, long non-coding RNAs, and pseudogenes. Our analysis revealed that 10.58% of all EV reads, and 18.67% of all cellular (WC) reads, corresponded to known full-length transcripts, with mRNAs representing the largest biotype for each group (EV = 58.13%, WC = 43.93%). We also observed that for many well-represented coding and non-coding genes, diverse full-length transcript isoforms were present in EV specimens, and these isoforms were reflective-of but often in different ratio compared to cellular samples.ConclusionThis work provides novel insights into the compositional diversity of poly-A transcript isoforms enriched within EVs, while also underscoring the potential usefulness of nanopore sequencing to interrogate secreted RNA transcriptomes.

Synthesis and Biological Evaluation of Novel Paracetamol-Triazole Conjugates

Some new triazole containing acetamide derivatives 9-20 using paracetamol as starting material were synthesized and their structure were characterized by FTIR, 1H-NMR, 13C-NMR and MS data. In vitro cytotoxic activities of all synthesized molecules against five cancer cell lines (human lung cancer A549, human chronic myelogenous leukemia K562, human breast cancer MCF-7, human prostate cancer PC-3, human neuroblastoma SH-SY5Y cell lines) were examined and were also tested their cytotoxic effect on mouse embryonic fibroblast cells (NIH/3T3) to define selectivity. MTT assay were used these in vitro activity studies. Additionally, twelve target compounds 9-20 were screened for their mPGES-1 and COX-1/2 inhibitory activities. While none of the synthesized compounds showed a significant inhibition against both cancer cells and mPGES-1 as well as COX-1/2, it was determined that they were not cytotoxic against healthy cells, too. Finally, ADMET data were presented by predicting the drug-like properties of newly synthesized compounds using computational methods.

Anticancer Activity of 3,5-Bis(dodecyloxy)Benzoate-PAMAM Conjugates with Indomethacin or Mefenamic Acid.

The synthesis of conjugates with nonsteroidal anti-inflammatory drugs could improve their activity with less toxicity and these compounds could be used for the treatment of cancer. The aim of the present investigation was the synthesis of 3,5-bis(dodecyloxy)benzoate - PAMAM conjugates with indomethacin and mefenamic acid to examine their anticancer activity. The anticancer activity was studied of the conjugates against six human cancer cells U- 251, PC-3, K-562, HCT-15, MCF-7, SKLU-1, and the COS-7 (as a control) cell lines. The conjugates with indomethacin and mefenamic acid were characterized by 1H, 13C NMR one- and twodimension spectroscopy. All the conjugates synthetized with indomethacin or mefenamic acid showed anticancer activity against all the human cancer cell lines. The first generation of indomethacin conjugates showed better activity against the PC-3 (human prostatic adenocarcinoma) cell line than the second generation. But the second generation with indomethacin showed better activity against PC-3 than the first generation. The second-generation conjugate with mefenamic acid had strong selectivity to PC-3 cells with an IC50 value of 10.23 ± 1.2 μM in vitro. In the paper, we report the synthesis and spectroscopic analyses of new indomethacin or mefenamic acid conjugates. The overall results showed that the conjugate of the second generation with mefenamic acid could be a potential nanocarrier for human prostatic adenocarcinoma cancer treatment, our research will be continued.

Anti-Cancer Effects of Oxygen-Atom-Modified Derivatives of Wasabi Components on Human Leukemia Cells.

1-Isothiocyanato-6-(methylsulfinyl)-hexanate (6-MITC) is a natural compound found in Wasabia japonica. The synthetic derivatives 1-Isothiocyanato-6-(methylsulfenyl)-hexane (I7447) and 1-Isothiocyanato-6-(methylsulfonyl)-hexane (I7557) were obtained from 6-MITC by deleting and adding an oxygen atom to the sulfone group, respectively. We previously demonstrated that extensive mitotic arrest, spindle multipolarity, and cytoplasmic vacuole accumulation were induced by 6-MITC and inhibited the viability of human chronic myelogenous leukemia K562 cells. In this study, we examined the anti-cancer effects of 6-MITC derivatives on human chronic myelogenous leukemia (CML) cells. Autophagy was identified as the formation of autophagosomes with double-layered membranes using transmission electron microscopy. Cell cycle and differentiation were analyzed using flow cytometry. Apoptosis was detected by annexin V staining. After treatment with I7447 and I7557, the G2/M phase of cell cycle arrest was revealed. Cell death can be induced by a distinct mechanism (the simultaneous occurrence of autophagy and aberrant mitosis). The expression levels of acridine orange were significantly affected by lysosomal inhibitors. The natural wasabi component, 6-MITC, and its synthetic derivatives have similar effects on human chronic myelogenous leukemia cells and may be developed as novel therapeutic agents against leukemia.

Synthesis of Dendrimer Conjugates with Naproxen and their Anticancer Activity

Abstract: Here we report the easy synthesis of dendrimer conjugates with four and eight naproxen moieties at the periphery. The synthesis involved two steps protection-deprotection sequence joined with triethylene glycol. A comparison was made between the cytotoxicity of dendron-naproxen conjugates and that of G1.0 G2.0 dendrimer-naproxen conjugates. Cytotoxicity studies showed that dendron conjugates were toxic towards all cancer cell lines studied, and their toxicity was significantly lower than that of dendrimer conjugates. However, dendrimer conjugates showed higher cytotoxicity and selectivity against K-562 and SKLU- 1 than dendron conjugates.

NI-BODIPY-GO Nanocomposites for Targeted PDT.

Three multifunctional targeted NI-BODIPYs (10-12) and GO-(10-12) nanocarriers were fabricated. NI-BODIPYs are designed to facilitate non-covalent interaction with graphene oxide (GO) and target toward cancer cells for specific recognition with glucose moieties while efficiently producing singlet oxygen. We probed detailed characterization, fundamental photophysical/photochemical properties, and interactions with GO of such triplet photosensitizers and nanocarriers. The effect of the formation of nanohybrids with GO on singlet oxygen formation as well as on the efficacies of the molecules in terms of in vitro killing of cancer cells was evaluated with K562 human chronic myelogenous leukemia cells. Amazingly, it was observed that GO exhibited favorable interactions with the NI-BODIPY dyads and promoted the formation of singlet oxygen, while not showing any dark toxicity.

Pyrrole-type compounds from the flowers of Calotropis gigantea

Calotropis gigantea, a large shrub, has been used in traditional folk medicines for the treatment of fever, cough, swellings, bronchitis or dyspepsia. Previous studies on C. gigantea reported that its main constituents, specifically cardenolides and pregnanes, had cytotoxic activity against A549 human lung, Hela human cervical cancer cell lines and K562 human chronic myelogenous leukemia. This paper presents the isolation of chemical constituents from the flowers of C. gigantea (Apocynaceae) in order to provide more information about its chemical compounds to the database on medical plants in Vietnam. By using silica gel column chromatography, preparative TLC and eluting with organic solvents of different polarity, results showed that five pyrroles, including pollenopyrroside B (1), epi-acortatarin A (2), shensongine A (3), 5-methoxymethyl-1H-pyrrole-2-carbaldehyde (4), 1-[2-(furan-2-yl)-2-oxoethyl]pyrrolidin-2-one (5), were isolated from the CHCl3 extract of the flowers of C. gigantea (Apocynaceae), collected at Binh Thuan province in March, 2020. Their chemical structures were elucidated by HR-MS and 1D, 2D NMR spectra analysis and comparison with published data. All compounds were the first reported from C. gigantea.

Novel 1,2,4-triazoles derived from Ibuprofen: synthesis and in vitro evaluation of their mPGES-1 inhibitory and antiproliferative activity.

Some novel triazole-bearing ketone and oxime derivatives were synthesized from Ibuprofen. In vitro cytotoxic activities of all synthesized molecules against five cancer lines (human breast cancer MCF-7, human lung cancer A549, human prostate cancer PC-3, human cervix cancer HeLa, and human chronic myelogenous leukemia K562 cell lines) were evaluated by MTT assay. In addition, mouse embryonic fibroblast cells (NIH/3T3) were also evaluated to determine the selectivity. Compounds 18, 36, and 45 were found to be the most cytotoxic, and their IC50 values were in the range of 17.46-68.76µM, against the tested cancer cells. According to the results, compounds 7 and 13 demonstrated good anti-inflammatory activity against the microsomal enzyme prostaglandin E2 synthase-1 (mPGES-1) enzyme at IC50 values of 13.6 and 4.95µM. The low cytotoxicity and non-mutagenity of these compounds were found interesting. Also, these compounds significantly prevented tube formation in angiogenesis studies. In conclusion, the anti-inflammatory and angiogenesis inhibitory activities of these compounds without toxicity suggested that they may be promising agents in anti-inflammatory treatment and they may be supportive agents for the cancer treatment.

6,7-Dimethoxycoumarin Influences the Erythroid Differentiation of Human Chronic Myelogenous Leukemia K562 Cells through Regulating FOXO3/p27 Signal Pathway.

Objective To study the pharmacological activity and the mechanism of action of natural compounds derived from 6,7-dimethoxycoumarin on the differentiation of human chronic myeloid leukemia K562 cells. Methods We use MTT assay (Sigma-Aldrich, USA) to detect cell viability; use flow cytometry to analyze DNA content for cell cycle analysis; use benzidine staining to synthesize hemoglobin to determine K562 cell differentiation; use western blot analysis and qPCR to detect the expression levels of FOX03, P27, CDK4, and their phosphorylation; and use the AOBS laser scanning confocal system (Leica, Wetzlar, Germany) to analyze and quantify the number of positive green spots. The statistical methods used are one-way analysis of variance (ANOVA) and Dunnett's test to analyze within and between groups. Results In order to explore the effect of 6,7-dimethoxycoumarin on the differentiation of K562 cell erythrocytes, it was concluded that 6,7-dimethoxycoumarin promotes the differentiation of K562 cell erythrocytes; the proliferation of K562 cells was detected by MTT method, and the results showed that 6,7-dimethoxycoumarin can inhibit the proliferation of K562 cells; to evaluate the effect of 6,7-dimethoxycoumarin on the proliferation of K562 cells, the results showed that 6,7-dimethoxycoumarin increased the expression of FOXO3, P27, CDK4, and CDK65, and decreased the phosphorylation of CDK4 and CDK6 proteins. To further explore the effect of knocking out FOXO3 on cell differentiation, the results show that 6,7-dimethoxycoumarin can reduce the differentiation and proliferation of K562 cells by increasing the expression of FOXO3. Conclusion This study extended the understanding of the pharmacological activity of 6,7-dimethoxycoumarin and may provide a potential new target for the treatment of chronic myelogenous leukemia. However, we still need to further study the specific molecular capabilities of 6.7 dimethylcoumarin to understand their possible capture mechanism.

Restriction-Assembly: A Solution to Construct Novel Adenovirus Vector.

Gene therapy and vaccine development need more novel adenovirus vectors. Here, we attempt to provide strategies to construct adenovirus vectors based on restriction-assembly for researchers with little experience in this field. Restriction-assembly is a combined method of restriction digestion and Gibson assembly, by which the major part of the obtained plasmid comes from digested DNA fragments instead of PCR products. We demonstrated the capability of restriction-assembly in manipulating the genome of simian adenovirus 1 (SAdV-1) in this study. A PCR product of the plasmid backbone was combined with SAdV-1 genomic DNA to construct an infectious clone, plasmid pKSAV1, by Gibson assembly. Restriction-assembly was performed repeatedly in the steps of intermediate plasmid isolation, modification, and restoration. The generated adenoviral plasmid was linearized by restriction enzyme digestion and transfected into packaging 293 cells to rescue E3-deleted replication-competent SAdV1XE3-CGA virus. Interestingly, SAdV1XE3-CGA could propagate in human chronic myelogenous leukemia K562 cells. The E1 region was similarly modified to generate E1/E3-deleted replication-defective virus SAdV1-EG. SAdV1-EG had a moderate gene transfer ability to adherent mammalian cells, and it could efficiently transduce suspension cells when compared with the human adenovirus 5 control vector. Restriction-assembly is easy to use and can be performed without special experimental materials and instruments. It is highly effective with verifiable outcomes at each step. More importantly, restriction-assembly makes the established vector system modifiable, upgradable and under sustainable development, and it can serve as the instructive method or strategy for the synthetic biology of adenoviruses.

Semi-Synthesis, Cytotoxic Evaluation, and Structure-Activity Relationships of Brefeldin A Derivatives with Antileukemia Activity.

Brefeldin A (1), a potent cytotoxic natural macrolactone, was produced by the marine fungus Penicillium sp. (HS-N-29) from the medicinal mangrove Acanthus ilicifolius. Series of its ester derivatives 2–16 were designed and semi-synthesized, and their structures were characterized by spectroscopic methods. Their cytotoxic activities were evaluated against human chronic myelogenous leukemia K562 cell line in vitro, and the preliminary structure–activity relationships revealed that the hydroxy group played an important role. Moreover, the monoester derivatives exhibited stronger cytotoxic activity than the diester derivatives. Among them, brefeldin A 7-O-2-chloro-4,5-difluorobenzoate (7) exhibited the strongest inhibitory effect on the proliferation of K562 cells with an IC50 value of 0.84 µM. Further evaluations indicated that 7 induced cell cycle arrest, stimulated cell apoptosis, inhibited phosphorylation of BCR-ABL, and thereby inactivated its downstream AKT signaling pathway. The expression of downstream signaling molecules in the AKT pathway, including mTOR and p70S6K, was also attenuated after 7-treatment in a dose-dependent manner. Furthermore, molecular modeling of 7 docked into 1 binding site of an ARF1–GDP-GEF complex represented well-tolerance. Taken together, 7 had the potential to be served as an effective antileukemia agent or lead compound for further exploration.

Amphiphilic Fullerene-BODIPY Photosensitizers for Targeted Photodynamic Therapy.

Nanotheranostic tailor-made carriers are potent platforms for the treatment of cancer that propound a number of advantages over conventional agents for photodynamic therapy (PDT). Herein, four new heavy atom free amphiphilic glucose-BODIPY-fullerene dyads (14-17) endowed with carbohydrate units in the styryl units, which can also form nanomicelles (14-17NM) with Tween 80 for PDT are reported. Glucose-BODIPY-fullerene systems (14-17) and related nanomicelles (14-17NM) have been prepared to emcee efficient singlet oxygen generation upon light irradiation. In vitro anti-tumor effects of the compounds 14-17 and 14-17NM in the presence of light and in darkness have been investigated with K562 human chronic myelogenous leukemia suspension cells. Anti-tumor toxicity upon light irradiation was due to the formation of singlet oxygen and reactive oxygen species (ROS). This study may provide an accomplished example of efficient PDT applications based on nanovehicles fabricated with universal spin converter, fullerene, light harvesting unit, BODIPY dyes conjugated with targeting units to fight against cancer.

Flow Cytometric Quantification of Cytotoxic Activity in Whole Blood Samples.

Current methods for the determination of cell-mediated cytotoxic activity in blood samples usually isolate peripheral blood mononuclear cells by density gradient centrifugation or alternatively use erythrocyte lysis. Both centrifugation and red cell lysis can cause cellular depletion and cell dysfunction, resulting in erroneous measurements. To address limitations of current assays, we developed an improved strategy to determine cellular cytotoxicity using flow cytometry. Viable nucleic acid stains are used to identify live nucleated cells and discriminate them from non-nucleated erythrocytes, platelets, and debris while avoiding lysing and washing steps to maintain cell functionality. To detect target cells, we have used two different labeling approaches. In the first approach, EGFP-labeled K562 human chronic myelogenous leukemia cells provide a "ready-to-use" target without the need of additional for labeling or staining. For the second approach, we perform parallel cytotoxicity assays in the presence of wild-type K562 cells previously loaded with a fluorescent dye that has spectral properties similar to those of EGFP. Given the importance of cytotoxic assays and the deleterious effects of current sample preparation methods, the aim of this study was to adapt this "untouched cells" flow cytometry method to study cytotoxic activity using unlysed whole blood samples and fluorescent target cells. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Sample preparation for cell-mediated cytotoxic activity determination in unlysed whole blood Basic Protocol 2: Protocol preparation, sample acquisition, and gating strategy for flow cytometric identification of cell-mediated cytotoxic activity using unlysed whole blood samples Support Protocol 1: Optimization of the performance of target cell labeling approaches Support Protocol 2: Assessment of the linearity and reproducibility of cytotoxicity assays.

Bis-Bibenzyls from the Liverwort Pellia endiviifolia and Their Biological Activity.

Based on previous investigations where bis-bibenzyls isolated from liverworts showed various biological activities (cytotoxic, antimicrobial, and antiviral), we investigated their cytotoxic activity in several human cancer cell lines. From the methylene-chloride/methanol extract of the liverwort Pellia endiviifolia, three bis-bibenzyls of the perrottetin type were isolated, namely perrottetin E, 10′-hydroxyperrottetin E, and 10,10′-dihydroxyperrottetin E. The last two were found for the first time in this species. Their structures were resolved using 1D and 2D NMR, as well as by comparison with data in the literature. Cytotoxic activity of the isolated compounds was tested on three human leukemia cell lines, HL-60 (acute promyelocytic leukemia cells), U-937 (acute monocytic leukemia cells), and K-562 (human chronic myelogenous leukemia cells), as well as on human embryonal teratocarcinoma cell line (NT2/D1) and human glioblastoma cell lines A-172 and U-251, and compared to the previously isolated bis-bibenzyls (perrottetins) of similar structure. The isolated compounds exhibited modest activity against leukemia cells and significant activity against NT2/D1 and A-172. Overall, the most active cytotoxic compounds in this investigation were perrottetin E (1), isolated in this work from Pellia endiviifolia, and perrottetin F phenanthrene derivative (7), previously isolated from Lunularia cruciata and added for a comparison of their cytotoxic activity.

Quantification of Intracellular Thiols by HPLC-Fluorescence Detection.

Biothiols, such as cysteine and glutathione, play important roles in various intracellular reactions represented by the redox equilibrium against oxidative stress. In this study, a method for intracellular thiol quantification using HPLC-fluorescence detection was developed. Thiols were derivatized with a thiol-specific fluorescence derivatization reagent, viz. ammonium 7-fluoro-2,1,3-benzoxadiazole-4-sulfonate (SBD-F), followed by reversed-phase separation on an InertSustain AQ-C18 column. Six different SBD-thiols (homocysteine, cysteine, cysteinylglycine, γ-glutamylcysteine, glutathione, and N-acetylcysteine as an internal standard) were separated within 30 min using a citric buffer (pH 3.0)/MeOH mobile phase. The calibration curves of all the SBD-thiols had strong linearity (R2 > 0.999). Using this developed method, the thiol concentrations of human chronic myelogenous leukemia K562 cell samples were found to be 5.5–153 pmol/1 × 106 cells. The time-dependent effect of a thiol scavenger, viz. N-ethyl maleimide, on intracellular thiol concentrations was also quantified. This method is useful for elucidating the role of intracellular sulfur metabolism.

Increased ERK phosphorylation and caveolin-1 expression on K562 human chronic myelogenous leukemia cells by jacalin, a dietary plant lectin.

The potential antitumor effects of jacalin, the plant lectin that specifically recognizes the tumor-associated Thomsen-Friedenreich antigen has been extensively studied. We had earlier reported jacalin to be mitogenic to K562, the Bcr-Abl expressing erythroleukemia cell line. The dearth of studies highlighting the proliferative effects of jacalin and other lectins motivated us to unveil the mechanism underlying the mitogenic effects of jacalin. Caveolin-1 (cav-1) is an integral membrane protein, known to play a crucial role in cell signaling, lipid transport, and membrane trafficking. The role of cav-1 in tumorigenesis is considered to be controversial as it can suppress as well as promote tumor growth, depending on the cellular context. In the present study, we propose that cav-1 plays the central role in the mitogenic effects of jacalin on the K562 cells. In accordance, the mRNA, as well as protein expression of cav-1 was found to be upregulated in the jacalin-treated K562 cells as compared to the untreated control. Further, jacalin stimulation also increased the phosphorylation of ERK and Akt. The rationale that leads to the initial conjecture about cav-1 was that the sequence of jacalin possesses a cav-1-binding site.

9-(2-Phosphonyl-methoxyethyl)-adenine promotes erythrocytic differentiation and disrupts cell replication in chronic myelogenous leukemia K562 cells

Disruption during cellular differentiation can cause hematopoietic stem cells to proliferate uncontrollably, resulting in the development of cancer. Differentiation therapies are being investigated as a type of cancer treatment which involve inducing agents that promote the differentiation of cancer cells into those with similar properties to normal blood cells. These cells can then undergo apoptosis at an accelerated and controlled rate compared to cancer cells, making this a potential therapeutic technique. In this study, the ability of human chronic myelogenous leukemia K562 cells to undergo cellular differentiation in response to the inducing agent 9-(2-Phosphonyl-methoxy ethyl)-adenine (PMEA) is investigated. PMEA has previously been shown to disrupt cell replication, and promote erythrocytic differentiation in K562 cells. In order to further test the effectiveness of this inducer, cell proliferation was measured with a cell growth curve, hemoglobin presence was measured with benzidine staining, and gamma-globin expression (a protein subunit of fetal hemoglobin) was measured in both induced and uninduced K562 cell cultures via RT-qPCR and western blotting. The results indicate that PMEA slows cell replication, and promotes hemoglobin (and subsequently gamma-globin) expression in treated cells. In summary, the findings support the conclusion that PMEA is able to promote erythrocytic differentiation in K562 cells, and provides information that supports differentiation therapies as a method for cancer treatment.

Structure and in vitro antiproliferative activity of the acidic capsular polysaccharide from the deep-sea bacterium Psychrobacter submarinus KMM 225T

Psychrobacter submarinus KMM 225T is a Gram-negative bacterium isolated from a sea-water sample collected at a depth of 300 m in the Northwest Pacific Ocean. Here we report the structure of the capsular polysaccharide from P. submarinus KMM 225T and its effect on the viability and colony formation of cancer cells. The glycopolymer was purified by ultracentrifugation and chromatography methods, and the structure was elucidated using NMR spectroscopy and composition analyses. The following structure of the acidic capsular polysaccharide, containing 2-acetamido-2,4,6-trideoxy-4-[(S)-3-hydroxybutyramido]-d-glucose [d-QuipNAc4N(S-Hb)] and 4,6-O-[(S)-1-carboxyethylidene]-2-acetamido-2-deoxy-d-glucose [d-GlcpNAc4,6(S-Pyr)] was established:The capsular polysaccharide slightly reduced the viability but effectively suppressed the colony formation of different types of cancer cells, of which the most pronounced inhibition was shown for the human chronic myelogenous leukemia K-562 cells. [Display omitted]