Human Leukemia Cell Line K562 Research Articles

Design, synthesis, molecular docking and biological evaluation of novel 1,5-diarylpyrazole-N,O-dimethyl hydroxamate derivatives as antiproliferative agents.

A series of novel hybrid of 1,5-diarylpyrazole-N,O-dimethylhydroxamate derivatives were designed and synthesised in synthetically acceptable yields. All the new synthesized compounds were biologically evaluated for their in vitro cytotoxicity against a panel of five cell lines namely human colorectal adenocarcinoma cell line DLD1, human cervical cancer cell line Hela, human leukemia cell line K562, human pancreatic cancer cell line Suit-2 and human hepatocellular carcinoma cell line HepG2. Compound 7a showed a significant cytotoxicity against Hela cell line with IC50 value of 16 µM and a good cytotoxicity against DLD1 and HepG2 with IC50 values of 69.9 µM and 78.8µM. Also, compound 7a displayed a potent EGFR inhibitory activity with IC50= 4.00 µM, which was comparable to positive reference drug sorafenib (IC50 = 3.5 µM). Moreover, in-silico studies showed that compound 7a has excellent binding affinity to the active site of EGFR with binding score better than a multitarget kinase drug sorafenib and good binding affinity to JNK-2, which explains the anticancer activity of compound 7a.

HPRep: Quantifying Reproducibility in HiChIP and PLAC-Seq Datasets

HiChIP and PLAC-Seq are emerging technologies for studying genome-wide long-range chromatin interactions mediated by the protein of interest, enabling more sensitive and cost-efficient interrogation of protein-centric chromatin conformation. However, due to the unbalanced read distribution introduced by protein immunoprecipitation, existing reproducibility measures developed for Hi-C data are not appropriate for the analysis of HiChIP and PLAC-Seq data. Here, we present HPRep, a stratified and weighted correlation metric derived from normalized contact counts, to quantify reproducibility in HiChIP and PLAC-Seq data. We applied HPRep to multiple real datasets and demonstrate that HPRep outperforms existing reproducibility measures developed for Hi-C data. Specifically, we applied HPRep to H3K4me3 PLAC-Seq data from mouse embryonic stem cells and mouse brain tissues as well as H3K27ac HiChIP data from human lymphoblastoid cell line GM12878 and leukemia cell line K562, showing that HPRep can more clearly separate among pseudo-replicates, real replicates, and non-replicates. Furthermore, in an H3K4me3 PLAC-Seq dataset consisting of 11 samples from four human brain cell types, HPRep demonstrated the expected clustering of data that could not be achieved by existing methods developed for Hi-C data, highlighting the need for a reproducibility metric tailored to HiChIP and PLAC-Seq data.

Selective Chemical Activation of Piezo1 in Leukemia Cell Membrane: Single Channel Analysis.

Piezo1/2 are mechanosensitive calcium-permeable channels that can be activated by various modes of membrane deformation. The identification of the small molecule Yoda1, a synthetic Piezo1 agonist, revealed the possibility of chemical activation of the channel. Stimulating effects of Yoda1 on Piezo1 have been mainly documented using over-expressing cellular systems or channel proteins incorporated in artificial lipid bilayers. However, the activating effect of Yoda1 on native Piezo1 channels in the plasma membrane of living cells remains generally undefined, despite the increasing number of studies in which the agonist is utilized as a functional tool to reveal the contribution of Piezo1 to cellular reactions. In the current study, we used the human myeloid leukemia K562 cell line as a suitable model to examine chemically induced Piezo1 activity with the use of the patch-clamp technique in various specific modes. The functional expression of Piezo1 in leukemia cells was evidenced using a combinative approach, including single channel patch-clamp measurements. Utilizing our established single-current whole-cell assay on K562 cells, we have shown, for the first time, the selective real-time chemical activation of endogenously expressed Piezo1. Extracellular application of 0.5–1 µM Yoda1 effectively stimulated single Piezo1 currents in the cell membrane.

The WASP P460S Mutation Causes a New Phenotype of WASP Mutations Related Disorder: X-Linked Pancytopenia

Mutations of the Wiskott-Aldrich Syndrome Protein (WASP) are responsible for a rare and severe disease: Wiskott-Aldrich Syndrome (WAS), including classic Wiskott-Aldrich Syndrome (WAS), X-linked thrombocytopenia (XLT), and congenital X-linked neutropenia (XLN). Classic WAS patients present typical WAS manifestation: eczema, thrombocytopenia, small platelet and recurrent infection, while XLT patients present thrombocytopenia, and XLN patients present congenital neutropenia. Bone marrow failure (BMF) is a series diseases characterized by pancytopenia in peripheral-blood(PB), different degree of bone marrow hypocellularity. In this study, we present two unrelated boys with pancytopenia who were admitted to our hospital on account of declining blood cells and different degree of hematopoietic failure. We identified a new WAS gene mutation C1378T inducing the WASP P460S mutation in both penitents by the second generation sequencing. Furthermore, one case developed T cell acute lymphoblastic leukemia (T-ALL) after severe pancytopenia recovered for 4 years and relapsed in mediastinum transplanted with cord blood for 1 year, another case recovered after haploidentical transplantation and kept stable for 1 year. To date, the role of WAS gene mutation in aplastic anemia-like hematopoietic failure remains unknown. We further verified WASP P460S mutation in these two patients by Sanger sequencing. In patient's PB cells, normal expression level of total WASP proteins was detected. This notion was different from general WASP deficiency classic WAS or XLT patients. To test the function of WASP P460S mutation in pancytopenia, we examined the effect of WASP P460S mutation on cell proliferation. Human myelogenous leukemia K562 cell line, which lacks endogenous WASP, was transfected with lentivirus vectors carrying mutant or wild type of WAS gene. We found that the cells expressing WASP P460S grew significantly slower than the cells expressing the wild type. Moreover, actin polymerization assay showed that increased actin polymerization function in WASP P460S mutation compared with wild type. In addition, P460S mutation had no obvious effect on Daunorubicin-induced apoptosis response. Our findings revealed that the WASP P460S mutation played a role in the inhibition of cell proliferation and actin polymerization which may lead to a new phenotype for WASP mutation related X-linked pancytopenia. DisclosuresNo relevant conflicts of interest to declare.

Histone Deacetylase Inhibitor Depsipeptide (FK228) Induces Apoptosis in Leukemic Cells by Facilitating Mitochondrial Translocation of Bax, Which Is Enhanced by Proteasome Inhibitor Bortezomib.

Histone deacetylase (HDAC) inhibitors are a promising candidate for molecular-targeted therapy for leukemia. In this study, we investigated the mechanisms of cytotoxic effects of depsipeptide (FK228), one of the most effective HDAC inhibitors against leukemia, using human myeloid leukemic cell lines HL-60 and K562. We found that FK228 activated caspase-9 and a subsequent caspase cascade by perturbing the mitochondrial membrane to release cytochrome c, which was almost completely blocked by overexpression of Bcl-2. The mitochondrial damage was caused by the translocation of Bax but not other proapoptotic Bcl-2 family proteins to the mitochondria. FK228 did not affect the interaction between Bax and Bax-adaptor proteins such as 14–3–3 theta and Ku70. FK228-induced apoptosis and mitochondrial translocation of Bax were markedly enhanced by the proteasome inhibitor bortezomib. The synergistic action of FK228 and Bortezomib was at least partly mediated through conformational changes of Bax, which facilitate its translocation to the mitochondria. These results suggest that the combination of HDAC inhibitors and proteasome inhibitors is useful for the treatment of leukemia especially in the context of molecular-targeted therapy. The status of Bcl-2 and Bax may influence the sensitivity of tumors to this combination, and thus, can be a target of further therapeutic intervention.

S100 Calcium-Binding Protein P Secreted from Megakaryocytes Promotes Osteoclast Maturation.

Megakaryocytes (MKs) differentiate from hematopoietic stem cells and produce platelets at the final stage of differentiation. MKs directly interact with bone cells during bone remodeling. However, whether MKs are involved in regulating bone metabolism through indirect regulatory effects on bone cells is unclear. Here, we observed increased osteoclast differentiation of bone marrow-derived macrophages (BMMs) cultured in MK-cultured conditioned medium (MK CM), suggesting that this medium contains factors secreted from MKs that affect osteoclastogenesis. To identify the MK-secreted factor, DNA microarray analysis of the human leukemia cell line K562 and MKs was performed, and S100 calcium-binding protein P (S100P) was selected as a candidate gene affecting osteoclast differentiation. S100P was more highly expressed in MKs than in K562 cells, and showed higher levels in MK CM than in K562-cultured conditioned medium. In BMMs cultured in the presence of recombinant human S100P protein, osteoclast differentiation was promoted and marker gene expression was increased. The resorption area was significantly larger in S100P protein-treated osteoclasts, demonstrating enhanced resorption activity. Overall, S100P secreted from MKs promotes osteoclast differentiation and resorption activity, suggesting that MKs indirectly regulate osteoclast differentiation and activity through the paracrine action of S100P.

DNA binding ability and cytotoxicity, cell cycle arrest and apoptosis inducing properties of a benzochromene derivative against K562 human leukemia cells

Chromene and its derivatives are generally spread in nature. Heterocylic-based compounds like chromenes have displayed pharmacological activities. Chromene derivatives are critical due to some biological features such as anticancer activity. CML, chronic myelogenous leukemia, is a fatal malignancy determined by resistance to apoptosis and contains the Philadelphia chromosome. Induction of apoptosis is one of the main approaches in cancer therapy. In this research, benzochromene derivative, 2-amino-4-(4-methoxy phenyl)-4H-benzochromene-3-carbonitrile (4-MC) was tested for cytotoxic and apoptotic induction activities in the human leukemic K562 cell line. The MTT growth inhibition assay was used to determine the cellular growth and survival. Moreover, the binding attribute of 4-MC with double helix DNA was assessed by some spectroscopic and viscosity measurement, and also for docking analysis. 4-MC exhibited good cytotoxicity on K562 cell line and the IC50 value was calculated to be 30 µM. Furthermore, the mechanisms of apoptosis induction were determined morphologically by fluorescence dual staining with acridine orange and ethidium bromide and cell cycle analysis was based on DNA content, as well as the presence of phosphatidyl serine on the outside of the cells by the flow cytometric method. The results showed that 4-MC had potent cytotoxic activity via sub-G1 cell cycle arrest and induction of apoptosis. The experimental and simulation studies reported that 4-MC binds to ctDNA through groove binding mode with the binding constant (K b) of 2.5 × 103 M−1. These data represent a considerable anticancer potential of 4-MC and could be suggested for further pharmacological studies.

Anti-chronic myeloid leukemia activity and quantitative structure-activity relationship of novel thiazole aminobenzamide derivatives

The anti-chronic myeloid leukemia activity of thiazole aminobenzamide derivatives in vitro was tested by a methanethiosulfonate (MTS)-based viability assay method, and the result showed that some compounds exhibited good inhibitory activities against human chronic myeloid leukemia cell line K562, imatinib-resistant strain K562/R and T135I mutant cell line BaF3-ABL-BCR-T315I. Comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) methods were used to analyze the relationship between the structure of thiazole aminobenzamide derivatives and the inhibition of K562/R cell activity. In CoMFA, Q2 was 0.899 and R2 was 0.963; in CoMSIA, Q2 and R2 were 0.840 and 0.903, respectively. These data indicated that the selected test set showed suitable external predictive ability. Combined with the contour map results, we further analyzed the three-dimensional quantitative structure (3D-QSAR) model. The results demonstrated that in the backbone of the thiazole aminobenzamide derivative, the substitution of a small group at R1 position, or the introduction of a hydrophilic group at R2 position, or the introduction of a large-volume amino acid at R3 position may be beneficial to improve the anti-CML activity of the compound.

Induction of apoptosis by Kola nut extract as a recent and promising treatment strategy for Leukemia

Kola nut extracts have recently been reported to contain chemopreventive compounds providing several pharmacological benefits. This study investigated Kola nut extracts' anti-cancer activity on human immortalized myelogenous leukemia cell line K562 through apoptosis and cell cycle arrest. Fresh Kola nuts were prepared as powder and dissolved in DMSO. Different concentrations (50, 100, 150, 200, and 250 μg/ml) of working solutions were prepared. The K562 cells were treated with the different concentrations of Kola nut extract or vehicle control (10% DMSO) followed by incubation at 37°C for 24, 48, and 72 hours, respectively. Treatment activity was investigated in K562 cells; by Resazurin, and FITC/Propidium Iodide and 7-AAD stained cells to evaluate apoptotic cells and the cell cycle's progression. Inhibition of leukemia cell proliferation was observed. The extract effectively induced cell death, early and late apoptosis by approximately 30% after 24 and 48 hours incubation, and an increase in the rate of dead cells by 50% was observed after 72 hours of incubation. Also, cell growth reduction was seen at high dose concentrations (150 and 200 µg/ml), as evident by cell count once treated with Kola nut extract. The total number of apoptotic cells increased from 5.8% of the control group to 27.4% at 250 µg/ml concentration. Moreover, Kola nut extracts' effects on K562 cells increased gradually in a dose and time-dependent manner. It was observed that Kola nut extracts could arrest the cell cycle in the G2/M phase as an increase in the number of cells by 29.8% and 14.6 % were observed from 9.8% and 5.2% after 24 and 48 hours of incubation, respectively. This increase was detected in a dose and time-dependent manner. Kola nut extracts can be used as a novel anti-cancer agent in Leukemia treatment as it has shown significant therapeutic potential and therefore provides new insights in understanding the mechanisms of its action. Keywords: Kola nut extracts, Leukemia, K562 cell line, Apoptosis, Cancer.

Appraisal of pyrrole as connecting unit in hydroxamic acid based histone deacetylase inhibitors: Synthesis, anticancer evaluation and molecular docking studies

Pyrrole is a biologically active scaffold, which itself possess noticeable anticancer activity against several types of cancer specially leukemia, lymphoma, and myelofibrosis. SAHA and its synthetic analogs has demonstrated potent antitumor activity against numerous human cancer lines and different classes of HDACs. The HDAC inhibitor possessing pyrrole as linker moiety has been developed for anticancer property. The objective of present studies was to incorporate pyrrole as connecting unit in hydroxamic acid based HDAC inhibitors for their anticancer evaluation and molecular docking studies. A series of novel 4-substituted methyl 6-(3-acetyl-2-methyl-1H-pyrrol-1-yl)hexanoate [3(a-z)] and 4-substituted 6-(3-acetyl-2-methyl-1H-pyrrol-1-yl)-N-hydroxyhexanamide [4(a-z)] were synthesized. These analogs were evaluated for their anticancer activity using in-vitro method against leukemia (K-562), lung (A-549), breast (MCF-7), and cervical (HeLa) human cancer cell lines using Sulforhodamine B (SRB) assay method, HDAC1 and HDAC6 inhibitory assay and binding mode analysis using molecular docking studies. The in-vitro studies of 3(a-z) indicated that substitution with electron donating groups produces active or moderately active compounds. Interestingly, p-nitro-substituted molecule produced a most active derivative in the series. The in-vitro anticancer study of 4(a-z) indicated that the unsubstituted phenyl derivative, 6-(3-acetyl-2-methyl-4-phenyl-1H-pyrrol-1-yl)-N-hydroxy-hexanamide (4a) have moderate antitumor activity against K-562 human leukemia cell line. Substitution at 4-phenyl ring with weak and moderate electron withdrawing groups, such as fluoro, chloro, and bromo potentiated the cytotoxic activity. The 4(a-z)] were docked against different HDAC proteins to determine the exact binding mode and orientation. These synthetic analogs have similar binding mode as SAHA on the active pocket. The pyrrole based novel SAHA analogs 3(a-z) and 4(a-z) displayed promising anticancer activity. These studies can be further employed for the design and development of novel SAHA analogs with promising anticancer activity.

Evaluation of Anticancer Action of Martynia annua Linn Root Extract on Different Human Cancer Cell Lines

Background: In the last few decades, plants have been playing a vital role in treating cancer and infectious diseases. Natural products have been rediscovered as effective methods of drug production amid advances in combinatorial chemistry. Roots of Martynia annua are being used as a folklore remedy for the treatment of cancer and rheumatism successfully.
 Aims of the Study: In the present study, ethanolic, aqueous and hydro-ethanolic root extracts of Martynia annua were screened for in vitro cytotoxicity activity using different cell lines.
 Settings and Design: In the experiment, lung cancer cell lines (A549), leukemia cancer cell lines (K562), oral cancer cell lines (SCC-40), breast cancer cell lines (MCF-7) & cervix cancer cell lines (SiHa) were studied on the extracts.
 Materials and Methods: The method used was Sulforhodamine B (SRB) assay technique in which growth inhibition of 50% (GI50) was analyzed by comparing it with standard drug Adriamycin (ADR) (doxorubicin).
 Results: Aqueous & ethanolic extract of Martynia annua root had shown high anticancer activity with GI50 value 11.3µg/ml and 20.4µg/ml respectively on human leukemia cell line K-562 but for human breast cancer cell line MCF-7, human lung cancer cell line A-549, human squamous cell carcinoma SCC-40 and human cervical cancer cell line SiHa the extracts showed activity in more than 80µg/ml.
 Conclusion: The anticancer activity of aqueous extract of Martynia annua root was found superior than the ethanolic extract in Human Leukemia Cell Line K-562. The study indicates that the Martynia annua root extracts are most effective against the fast proliferative cells (Leukemic cells) and possibly a cell cycle arrest (needed to be proved as future perspective) is the mode of action of the extract. To study its effect on targeted cancers, specific in vivo scientific studies and clinical trials should be carried out by further researchers.

Human Wharton's Jelly Stem Cell Secretions Inhibit Human Leukemic Cell Line K562 in vitro by Inducing Cell Cycle Arrest and Apoptosis.

Emerging resistance to the tyrosine kinase inhibitors that target the BCR-ABL1 oncoprotein has prompted research for novel therapeutics against chronic myeloid leukemia (CML). Herein, we evaluated the tumor inhibitory properties of the human Wharton’s jelly stem cells (hWJSCs) co-culture (hWJSC-CC) and their extracts, namely, the hWJSC-conditioned medium (hWJSC-CM; 100%) and hWJSC-lysate (hWJSC-L; 15 μg/ml), on a CML cell line K562 in vitro. The hWJSCs expressed mesenchymal stem cell (MSC)-related cluster of differentiation (CD) markers and demonstrated mesodermal tissue differentiation potential. The cell metabolic activity showed a mean maximal decrease in the K562 cells by 49.12, 41.98, and 68.80% following treatment with the hWJSC-CC, hWJSC-CM, and hWJSC-L, respectively, at 72 h. The sub-G1 population in the cell cycle was decreased by 3.2, 4.5, and 3.8% following treatment with the hWJSC-CC, hWJSC-CM, and hWJSC-L, whereas the G2/M cell population was increased by 13.7 and 12.5% with the hWJSC-CM and hWJSC-L, respectively, at 48 h. Annexin V–allophycocyanin (APC) assay showed an increase in the apoptotic cells by 4.0, 3.9, and 4.5% at 48 h. The expression of pro-apoptotic BAX and CASP3 genes were increased, whereas BIRC5 (Survivin) was decreased compared with the control. The pro-inflammation-related genes, namely, IFN-γ, TNF-α, IL-1β, IL-6, IL-8, and IL-12A, were decreased, whereas the anti-inflammatory genes, namely, IL-4 and IL-10, were increased following treatment with the hWJSC-CC, hWJSC-CM, and hWJSC-L at 48 h. Multiplex bead-based cytokine assay also demonstrated decreases in the pro-inflammatory cytokines (IFN-γ, TNF-α, IL-1β, IL-6, and IL-12) and an increase in the anti-inflammatory cytokine (IL-10) compared with the control. The pro-inflammatory cytokine IL-8 showed an increase with the hWJSC-CC and decreases with both the hWJSC-CM and the hWJSC-L. The hWJSCs and their extracts inhibited the K562 cells by causing cell cycle arrest and inducing apoptosis via the soluble cellular factors. However, an in vivo evaluation is necessary to unravel the true potential of the hWJSCs and their extracts before its use in CML inhibition.

Design, synthesis, and biological evaluation of novel bromo-pyrimidine analogues as tyrosine kinase inhibitors

In the present investigation we designed, synthesized and evaluated a novel series of bromo-pyrimidine analogues (6a-j,7a-e,9a-f,and10a-f) as anticancer agents. The compounds were characterized using spectroscopic studies and elemental analysis and screened for theirin vitrocytotoxic activity by MTT assay against four cancer cell lines including HCT116 (human colon cancer cell line), A549 (human lung cancer cell line), K562 (human chronic myeloid leukemia cell line), U937 (human acute monocytic myeloid leukemia cell line) as well as the normal human liver cell line, L02. Most of the compounds showed potent activity on K562 cells. Considering this, the compounds were evaluated for Bcr/Abl tyrosine kinase inhibitory activity by ADP-Glo assay. Dasatinib was used as standard drug for both cytotoxicity and tyrosine kinase inhibition studies. The compounds,6g,7d,9c,and10eemerged as potent Bcr/Abl kinase inhibitors. Hence, the potent compounds that arose out of this investigation are potential lead molecules to develop as an alternative to existing dasatinib therapy.

Sesquiterpene Alcohol Cedrol Chemosensitizes Human Cancer Cells and Suppresses Cell Proliferation by Destabilizing Plasma Membrane Lipid Rafts.

Chemosensitization of cancer cells with small molecules may improve the therapeutic index of antitumoral agents by making tumor cells sensitive to the drug regimen and thus overcome the treatment resistance and side effects of single therapy. Cell membrane lipid rafts are known to transduce various signaling events in cell proliferation. Sensitizing cancer cells may cause modulation of membrane lipid rafts which may potentially be used in improving anticancer drug response. Cedrol, a natural sesquiterpene alcohol, was used to treat human leukemia K562 and colon cancer HT-29 cell lines, and effects were observed. Cedrol decreased the cell viability by inducing apoptosis in both cell lines by activation of pro-apoptosis protein BID and inhibition of anti-apoptosis proteins Bcl-XL, Bcl-2, and XIAP. Cedrol activated the caspase-9-dependent mitochondrial intrinsic pathway of apoptosis. Furthermore, cedrol inhibited the levels of pAKT, pERK, and pmTOR proteins as well as nuclear and cytoplasmic levels of the p65 subunit of NF-κB. Cedrol caused redistribution of cholesterol and sphingomyelin contents from membrane lipid raft, which was confirmed by a combined additive effect with methyl-β-cyclodextrin (lipid raft-disrupting agent). Lipid raft destabilization by cedrol led to the increased production of ceramides and inhibition of membrane-bound NADPH oxidase 2 enzyme activity. Cholesterol/sphingomyelin-redistributing abilities of cedrol appear as a novel mechanism of growth inhibition of cancer cells. Cedrol can be classified as a natural lipid raft-disrupting agent with possibilities to be used in general studies involving membrane lipid raft modifications.

Synthesis, characterization and cytotoxicity evaluation of a novel magnetic nanocomposite with iron oxide deposited on cellulose nanofibers with nickel (Fe3O4@NFC@ONSM-Ni).

A heterogeneous, magnetically recoverable nanocomposite, Fe3O4@NFC@ONSM-Ni(ii) was prepared by immobilization of a novel Ni(ii) Schiff base complex on Fe3O4@NFC nanoparticles followed by treatment with melamine. This trinuclear catalyst has been characterized using several analytical techniques including FT-IR, TEM, Fe-SEM, EDX, DLS, ICP, TGA, VSM, and XRD. It was used as an efficient catalyst for one-pot solvent-free synthesis of 1,4-dihydropyridine and poly-hydro quinoline derivatives through Hantzsch reaction. This catalyst showed remarkable advantage over previously reported catalysts due to suitable conditions, short reaction time, high efficiency and lower catalyst load and timely recovery of the magnetic catalyst. Moreover, the effects of Fe3O4@NFC@ONSM-Ni(ii) nanoparticles on the in vitro proliferation of human leukemia cell line (k562) and human breast cancer cells (MDA-MB-231) were investigated. The results of MTT and Hochest assays suggested that the nanoparticles could effectively inhibit the proliferation of these cancer cells in a time- and concentration-dependent manner.

GC-MS analysis and in vitro Antioxidant, Cytotoxicity study of DCM-ME extract of Dendrophthoe falcata (L.F) Ettingsh leave against human lung carcinoma (A-549) and human Chronic Myelogenous leukemia (k-562) cell Line

GC-MS analysis and in vitro Antioxidant, Cytotoxicity study of DCM-ME extract of Dendrophthoe falcata (L.F) Ettingsh leave against human lung carcinoma (A-549) and human Chronic Myelogenous leukemia (k-562) cell Line

Transferrin-Bound Doxorubicin Enhances Apoptosis and DNA Damage through the Generation of Pro-Inflammatory Responses in Human Leukemia Cells.

Doxorubicin (DOX) is an effective antineoplastic drug against many solid tumors and hematological malignancies. However, the clinical use of DOX is limited, because of its unspecific mode of action. Since leukemia cells overexpress transferrin (Tf) receptors on their surface, we proposed doxorubicin–transferrin (DOX–Tf) conjugate as a new vehicle to increase drug concentration directly in cancer cells. The data obtained after experiments performed on K562 and CCRF-CEM human leukemia cell lines clearly indicate severe cytotoxic and genotoxic properties of the conjugate drug. On the other hand, normal peripheral blood mononuclear cells (PBMCs) were more resistant to DOX–Tf than to DOX. In comparison to free drug, we observed that Tf-bound DOX induced apoptosis in a TRAIL-dependent manner and caused DNA damage typical of programmed cell death. These fatal hallmarks of cell death were confirmed upon morphological observation of cells incubated with DOX or DOX–Tf. Studies of expression of TNF-α, IL-4, and IL-6 at the mRNA and protein levels revealed that the pro-inflammatory response plays an important role in the toxicity of the conjugate. Altogether, the results demonstrated here describe a mechanism of the antitumor activity of the DOX–Tf conjugate.

Down-regulation of Survivin and Bcl-2 concomitant with the activation of caspase-3 as a mechanism of apoptotic death in KG1a and K562 cells upon exposure to a derivative from ciprofloxacin family

Ciprofloxacin derivatives belong to a family of antibiotics called fluoroquinolones. Recently, these compounds have been recommended for the treatment of cancer. In the present study, we assessed the cytotoxicity of several new synthetic ciprofloxacin derivatives and the apoptosis-inducing activity of the most efficient derivative in two human myeloid leukemia K562 and KG1-a cell lines. Among the prepared ciprofloxacin derivatives, 1-cyclopropyl-7-(4-(2-((3,7-dimethyloct-6-en-1-yl)oxy)-2-oxoethyl)piperazin-1-yl)-6-fluoro-4-oxo-1,4dihydroquinoline-3-carboxylic acid (4-DMOCP) was more active compound with IC50 of 19.56 and 22.13 μM for K562 and KG1-a, respectively. Apoptotic activity of the 4-DMOCP was examined morphologically through Hoechst 33258 staining, Annexin V/PI double staining, and caspase-3 activity assays. Changes in the expression level of some apoptosis-related genes and protein, including Bcl-2, Bax, Survivin, p53, Caspase-8 and Caspase-9 were evaluated by the real-time quantitative PCR (qRT PCR) and western blotting. The qRT PCR analysis showed that 4-DMOCP induces apoptosis in both cell lines via the down-regulation of Survivin and Bcl2, up-regulation of caspase-8 and -9, as well as a time-dependent increase in the Bax/Bcl2 transcripts. The mRNA level of p53 was also increased in both cell lines. In addition, western blot analysis revealed that treatment with the compound, down-regulated the protein expression levels of Bcl2 and Survivin and up-regulated the protein level of Bax in both cell lines. These findings suggest that these new compounds can be good candidates for the treatment of acute and chronic myeloid leukemia.

In vitro antiproliferative activity of Amaryllidaceae species against the K562 human leukaemia cell line

Acute lymphocytic leukaemia is the most common leukemic cancer reported in children. Chemotherapy is the preferred treatment even though it continues to pose negative side effects of toxicity. Medicinal plants are reported to provide alternative treatment with lower toxicity levels. The three Amaryllidaceae species; Crinum bulbispermum, Boophone disticha, and Amaryllis belladonna Linnaeus have been reported for their anti-leukemic properties. These claims, however, lack supporting scientific data. The study aimed to investigate the anti-proliferative activity of the three Amaryllidaceae species against the human K562 leukaemia cells, as well as their phytochemical composition. The plants’ roots, bulbs and leaves were extracted with water, and sequentially with selected organic solvents. Cell antiproliferation was investigated using the SRB assay. Thin Layer Chromatography was performed to compare chemical profiles of different plant parts, and of plant samples collected from different geographic areas. Most plant parts tested positive for terpenoids and flavonoids. Only the bulbs contained phytosterols and alkaloids. Plant samples of C. bulbispermum obtained from two geographic areas had similar chemical profiles. Water bulb extract of C. bulbispermum and B. disticha showed over 70% cell growth inhibition at concentration of 10 µg/ml, while their methanol extracts showed over 50% cell growth inhibition at 100 µg/ml and 10 µg/ml. Methanol root extract of A. belladonna L exhibited 100% cell growth inhibition at the concentration of 50 µg/ml and over 80% at 25 µg/ml concentration. In general, the polar extracts exhibited highest activity. The cell antiproliferation results obtained in this study support the use of the selected Amaryllidaceae species to treat leukemia as currently practiced in traditional medicine. The consistency of the constituents of the species, despite of their collection points, could enable standardization of traditional medicines.

Novel N-4-Piperazinyl Ciprofloxacin-Ester Hybrids: Synthesis, Biological Evaluation, and Molecular Docking Studies

A series of novel N-4-piperazinyl ciprofloxacin-ester hybrids has been synthesized and the structures confirmed by1H and 13C NMR, FT-IR spectral data, and elemental analysis. The products have been tested in vitro for their antibacterial activity against six bacterial strains (MRSA, Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli,Salmonella enterica, and Klebsiella pneumoniae) and have demonstrated good antibacterial activity with MIC values range 6.25–200 µg/mL. Antifungal and cytotoxic activities of the products have been tested against Candida kefyr and human leukemia K562 cell line, respectively. All compounds inhibit growth of K562 cells more efficiently than the parent ciprofoxacin in a dose- and duration-dependent way. Molecular docking studies performed for the compound 3i indicates that similarly to ciprofloxacin it can act as an inhibitor of S. aureus DNA gyrase.