Chronic Myelogenous Leukemia Cells Research Articles

Extracellular vesicles enhance the in vivo antitumor effects of millettia species-derived compounds in chronic myelogenous leukemia therapy.

Several Millettia species are being investigated as medicinal ingredients due to their promising anti-cancer and anti-inflammatory properties. However, the application of Millettia species-derived compounds has been severely hindered by their poor aqueous solubility, rapid metabolism, and low bioavailability. Extracellular vesicles (EVs), which as membrane-bound phospholipid vesicle initiatively secreted through a variety of mammalian cells, are increasingly recognized as promising drug delivery vehicles. Therefore, EVs are with great potential to enhance both the stability and efficacy of the Millettia species-derived compounds in treatment. In this study, extracellular vesicles derived from chronic myelogenous leukemia cells are developed for delivering the extracts of Millettia speciosa Champ and Millettia pachyloba Drake-derived Homobutein. Notably, Homobutein-loaded EV (hEV) formed a stable and homogenous nanosized particle with high entrapment efficiency up to 55.7%. Moreover, EVs loaded with Homobutein were significantly more potent than free drugs in inhibiting K562 cell proliferation. The results demonstrated that intravenous injection of EV loaded with Homobutein effectively inhibits tumor growth in tumor-bearing mice compared to free Homobutein. Hence, this strategy can effectively enhance the efficacy of Millettia species-derived drugs in chronic myelogenous leukemia therapy.

P-373 Melatonin and chemotherapy: does the proposed fertoprotective agent impair the anti-tumor effects of cancer therapy?

Abstract Study question Does the proposed fertoprotective agent melatonin interfere with the anti-cancer activity of imatinib chemotherapy in a chronic myelogenous leukemia (CML) cell line? Summary answer At low concentrations, melatonin demonstrates mild inhibition of imatinib activity, however this is overcome at therapeutic concentrations. Melatonin also shows anti-tumor activity against CML. What is known already A harmful consequence of cancer therapy is a resultant loss of fertility. Pharmacologic interventions that reduce radiation or chemotherapy-induced gonadotoxicity are a major unmet medical need. Several ‘fertoprotective’ agents have shown promise in protecting the gonads from injury during treatment, including melatonin. However, melatonin is not currently applied in humans for this purpose. Key safety and efficacy data are needed to move potential fertoprotective agents into clinical trials. Study design, size, duration We evaluated the interaction of varying combined concentrations of melatonin and imatinib, a tyrosine kinase inhibitor, within an in-vitro matrix experiment. The interaction was be evaluated within K562, a cell line derived from human chronic myelogenous leukemia (CML). This chemotherapy and cell line were selected due to CML’s dependence on BCR-ABL for survival, which is inhibited by imatinib, permitting direct evaluation of melatonin-imatinib cross-interaction. Participants/materials, setting, methods K562 were seeded in 384-well plates into which increasing concentrations of imantinib and melatonin were progressively dispensed. The cells were cultured for 48 hours. Viable cell concentrations were then determined using a cell luminescent assay. Drug interaction was then determined using drug synergy analysis software.The expected drug combination responses were calculated based on ZIP reference model using SynergyFinder 3.0. Deviations between observed and expected responses with positive and negative values denote synergy and antagonism respectively. Main results and the role of chance Melatonin demonstrated toxicity to K562 CML cell lines independent of imatinib, with a mean inhibition of cell growth of 74.7% at 1uM, CI [69.6%, 79.7%]. This anti-tumor activity was progressively seen at concentrations >0.1 uM. At low imatinib concentrations (<0.2 uM), melatonin decreased the anti-cancer potency of imatinib. This effect was overcome at higher concentrations of imatinib. The overall mean synergy score was -5.87, CI [-7.145, -4.588]. Limitations, reasons for caution These experiments were carried out in an in-vitro setting in a tightly controlled environment. In a clinical setting, the complexity of potential interactions between melatonin and chemotherapy will increase (i.e. metabolism, distribution), thus animal models will be a necessary next step of evaluation before clinical safety trials may proceed. Wider implications of the findings Melatonin may serve as an inexpensive, well-tolerated adjuvant to help protect the gonad from chemotherapy, while additionally exhibiting its own anti-cancer effects in certain settings. Our preliminary data suggests that the risk of melatonin to impair active imatinib treatment may be low, however continued investigation is necessary. Trial registration number Not applicable

Polyimidazole ligands: Copper(II) complexes and antiproliferative activity in cancer cells

The design of novel chelators for therapeutic applications has been the subject of extensive research to address various diseases. Many chelators can manipulate the levels of metal ions within cells and effectively modulate the metal excess. In some cases, chelators show significant toxicity to cells.We investigated polyimidazole ligands by potentiometry and UV–Vis spectroscopy for their ability to form copper(II) complexes. We also compared the antiproliferative activity of the polyimidazole ligands and their copper(II) complexes with polypyridine ligands in CaCo-2 (colorectal adenocarcinoma), SH-SY5Y (neuroblastoma) and K562 (chronic myelogenous leukemia) cells and normal HaCaT (keratinocyte) cells.Polyimidazole ligands are less cytotoxic than their analogous polypyridine ligands. All polyimidazole ligands, except the tetraimidazole ligand for K562 cells, did not show any significant effect on the viability of cancer and normal cells. In contrast, the cytotoxic activity of polypiridine ligands was also observed in normal cells with IC50 values similar to those of cancer cells.Tetra imidazole ligand, the only ligand active on the leukemic K562 cell line, induced caspase-dependent apoptosis and increased intracellular reactive oxygen species production with mitochondrial damage.The low cytotoxicity of the polyimidazole ligands, even if it limits their use as anticancer agents, could make them useful in other medical applications, such as in the treatment of metal overload, microbial infections, inflammation or neurodegenerative disorders.

Optimizing Coreopsis tinctoria Flower Extraction and Inhibiting CML Activity: Box-Behnken Design.

Chronic myelogenous leukemia (CML) is an uncommon type of cancer of the bone marrow associated with high mortality. Although several effective therapies have been developed to reduce symptoms in patients with CML, many of these methods are associated with side effects. Coreopsis tinctoria Nutt. (C. tinctoria) is a natural medicinal material that possesses antioxidant and anticancer activities. Yet, its effect in treating leukemia has still not been fully explored. To optimize the C. tinctoria flower extraction process and investigate whether these extracts can impair CML cell survival. The extraction process of C. tinctoria was optimized by the Box-Behnken design response surface method. K562 cells were treated with different volumes (0, 10, 25, 50, and 100 µL) of C. tinctoria flower extracts. The effect of C. tinctoria extract on cell morphology and cell apoptosis was assessed by light microscopy, laser confocal microscopy, and flow cytometry. We established the following optimized C. tinctoria flower extraction conditions: temperature of 84.4 °C, extraction period of 10 mins, solid-liquid ratio of 1:65, and times 4. These conditions were applied for C. tinctoria flower extraction. Pre-incubation of extracts prepared under the aforementioned optimal conditions with K562 cells induced cell cytotoxicity and cell apoptosis. C. tinctoria flower extracts exert obvious anti-leukemia effects in vitro and may be a potential drug candidate for leukemia treatment.

ASP210: a potent oligonucleotide-based inhibitor effective against TKI-resistant CML cells.

Clinical experience with tyrosine kinase inhibitors (TKIs) over the past two decades has shown that, despite the apparent therapeutic benefit, nearly 30% of patients with chronic myelogenous leukemia (CML) display primary resistance or intolerance to TKIs, and approximately 25% of those treated are forced to switch TKIs at least once during therapy due to acquired resistance. Safe and effective treatment modalities targeting leukemic clones that escape TKI therapy could hence be game changers in the professional management of these patients. Here, we aimed to investigate the efficacy of a novel therapeutic oligonucleotide of unconventional design, called ASP210, to reduce BCR-ABL1 mRNA levels in TKI-resistant CML cells, with the assumption of inducing their apoptosis. Imatinib- and dasatinib-resistant sublines of BCR-ABL1-positive MOLM-7 and CML-T1 cells were established and exposed to 0.25 and 2.5 µM ASP210 for 10 days. RT-qPCR showed a remarkable reduction of the target mRNA level by >99% after a single application. Cell viability was monitored daily by trypan blue staining. In response to the lack of driver oncoprotein BCR-ABL1, TKI-resistant CML cells underwent apoptosis regardless of the presence of the clinically relevant T315I mutation by day 5 after redosing with ASP210. The effect was selective for cancer cells, indicating a favorable safety profile for this therapeutic modality. Furthermore, the spontaneous uptake and high intracellular concentrations of ASP210 suggest its potential to be effective at relatively low doses. The present findings suggest that ASP210 is a promising therapeutic avenue for patients with CML who fail to respond to TKI therapy.NEW & NOTEWORTHY Effective treatment modalities targeting leukemic clones that escape tyrosine kinase inhibitor (TKI) therapy could be game changers in the professional management of patients displaying primary resistance, intolerance, or acquired resistance to TKIs. Although delivering authentic innovations today is more complex than ever, we developed a highly potent and safe oligonucleotide-based modality against BCR-ABL1 mRNA named ASP210 that effectively induces cell death in BCR-ABL1-positive TKI-resistant cells while sparing BCR-ABL1-negative healthy cells.

Liver X receptor activation in chronic myelogenous leukemia cells yields distinct mass fingerprints by whole cell MALDI-TOF MS, which correspond to changes in cell viability, gene expression, and differentiation markers

Liver X receptor (LXR) agonists, including synthetic ligands or naturally-occurring oxysterols, exert promising lipid-modulating, anti-inflammatory, and anti-tumor effects. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) whole cell mass spectrometry (MS) shows promise in chronic disease and food science research, clinical diagnostics of cancer cells and bacterial pathogens, and drug/nutraceutical discovery due to its relatively low-cost, rapid, reliable, and high-throughput ability to identify unique cell phenotypes and differentiation states of immune cells that play essential roles in chronic metabolic and inflammatory disease pathophysiology. However, optimization of whole cell MALDI-TOF MS-based methods to assess cellular changes in response to pharmaceutical and/or nutraceutical treatment warrants further study. Thus, we investigated whether whole cell MALDI-TOF MS could detect cellular phenotype changes of human stem-like erythroleukemia K562 cells – a model for chronic myelogenous leukemia (CML) – induced by the LXR agonist TO-901317, a synthetic ligand that mimics effects of naturally-occurring oxysterols, which are oxidized cholesterol derivatives formed under conditions of high cellular cholesterol concentrations and in food products. TO-901317 dose- and time-dependently altered mRNA expression of cholesterol flux genes, including ATP-binding cassette transporter A1 (ABCA1), LDL-receptor (LDLR), HMG-CoA reductase (HMGCR), and reduced cellular cholesterol content by 22.9% at 24 h. TO-901317 additionally dose- and time-dependently impacted K562 cell viability, number, size, and reduced mRNA expression of the anti-apoptotic gene BCL2L1 by 43.3%. These effects corresponded to induced gene expression of erythroid markers and hemoglobin content, suggesting that LXR activation may promote erythroid lineage differentiation. Whole cell MALDI-TOF MS mass fingerprinting revealed distinct proteomic phenotypes between TO-901317 vs. untreated cells, and identified histone 2 A and histone H4 as uniquely expressed proteins. These findings not only elucidate a novel role for LXR agonists in a model of CML, but demonstrate that mass fingerprints obtained by whole cell MALDI-TOF mass spectrometry effectively distinguish between treatment-induced cell phenotypes.

Crystal structure and in vitro biological studies of a Pt(II) complex based on gallic acid and triphenylphosphine

Gallic acid is a natural polyphenol found in a variety of fruits, plants and nuts that has several biological properties, such as anti-oxidant, anti-inflammatory, and antitumor, among other activities. Some studies have proven that metal complexation could be an interesting strategy to enhance its pharmacological activities. Taking that into account, we report here the synthesis, spectral characterization (FTIR, 1H, 13C{1H}, 31P{1H} and 195Pt{1H} NMR), structural analysis, and biological activities of a new platinum(II) complex bearing gallic acid (ga) and triphenylphosphine (PPh3) as ligands. Spectral data suggest that a gallic acid molecule chelates the metal via two deprotonated phenolic oxygen atoms and two monodentate triphenylphosphines complete the coordination sphere. Furthermore, X-ray data support that the platinum(II) ion adopts a slightly distorted square-planar coordination environment. Time-dependent 1H NMR spectra at room temperature suggest that the complex is very stable in DMSO for at least 48 h. Subsequently, the cytotoxic activity of the platinum(II) complex was assessed against chronic myelogenous leukemia cells (k562) and in a non-cancerous cell line (LLCMK2). The complex was more active than gallic acid, cisplatin and carboplatin against the K562 cell line, exhibiting outstanding activity (IC50 = 0.75 μM). When tested against Mycobacterium tuberculosis, the complex showed good activity with a MIC value of 3.75 μg/mL. The results reported here reinforce the antitumor and antimycobacterial potential of metal complexes containing gallic acid and derivatives.

Herpesvirus Entry Mediator as an Immune Checkpoint Target and a Potential Prognostic Biomarker in Myeloid and Lymphoid Leukemia.

Herpesvirus entry mediator (HVEM) is a molecular switch that can modulate immune responses against cancer. The significance of HVEM as an immune checkpoint target and a potential prognostic biomarker in malignancies is still controversial. This study aims to determine whether HVEM is an immune checkpoint target with inhibitory effects on anti-tumor CD4+ T cell responses in vitro and whether HVEM gene expression is dysregulated in patients with acute lymphocytic leukemia (ALL). HVEM gene expression in tumor cell lines and peripheral blood mononuclear cells (PBMCs) from ALL patients and healthy controls was measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Tumor cells were left untreated (control) or were treated with an HVEM blocker before co-culturing with CD4+ T cells in vitro in a carboxyfluorescein succinimidyl ester (CFSE)-dependent proliferation assay. HVEM expression was upregulated in the chronic myelogenous leukemia cell line (K562) (FC = 376.3, p = 0.086) compared with normal embryonic kidney cells (Hek293). CD4+ T cell proliferation was significantly increased in the HVEM blocker-treated K562 cells (p = 0.0033). Significant HVEM differences were detected in ALL PBMCs compared with the controls, and these were associated with newly diagnosed ALL (p = 0.0011) and relapsed/refractory (p = 0.0051) B cell ALL (p = 0.0039) patients. A significant differentiation between malignant ALL and the controls was observed in a receiver operating characteristic (ROC) curve analysis with AUC = 0.78 ± 0.092 (p = 0.014). These results indicate that HVEM is an inhibitory molecule that may serve as a target for immunotherapy and a potential ALL biomarker.

Association of poly(rC)-binding protein-2 with sideroflexin-3 through TOM20 as an iron entry pathway to mitochondria

Iron is essential for all the lives and mitochondria integrate iron into heme and Fe-S clusters for diverse use as cofactors. Here, we screened mitochondrial proteins in KU812 human chronic myelogenous leukemia cells by glutathione S-transferase pulldown assay with PCBP2 to identify mitochondrial receptors for PCBP2, a major cytosolic Fe(II) chaperone. LC–MS analyses identified TOM20, sideroflexin-3 (SFXN3), SFXN1 and TOM70 in the affinity-score sequence. Stimulated emission depletion microscopy and proteinase-K digestion of mitochondria in HeLa cells revealed that TOM20 is located in the outer membrane of mitochondria whereas SFXN3 is located in the inner membrane. Although direct association was not observed between PCBP2 and SFXN3 with co-immunoprecipitation, proximity ligation assay demonstrated proximal localization of PCBP2 with TOM20 and there was a direct binding between TOM20 and SFXN3. Single knockdown either of PCBP2 and SFXN3 in K562 leukemia cells significantly decreased mitochondrial catalytic Fe(II) and mitochondrial maximal respiration. SFXN3 but not MFRN1 knockout (KO) in mouse embryonic fibroblasts decreased FBXL5 and heme oxygenase-1 (HO-1) but increased transferrin uptake and induced ferritin, indicating that mitochondrial iron entry through SFXN3 is distinct. MFRN1 KO revealed more intense mitochondrial Fe(II) deficiency than SFXN3 KO. Insufficient mitochondrial heme synthesis was evident under iron overload both with SFXN3 and MFRN KO, which was partially reversed by HO-1 inhibitor. Conversely, SFXN3 overexpression caused cytosolic iron deficiency with mitochondrial excess Fe(II), which further sensitized HeLa cells to RSL3-induced ferroptosis. In conclusion, we discovered a novel pathway of iron entry into mitochondria from cytosol through PCBP2-TOM20-SFXN3 axis.

Novel Mn(II) and Cu(II) metal complexes with sulfa drug-derived ligands as potent antimicrobial and anticancer agents: In vitro studies, ADMET profile and molecular docking

The present work deals with the synthesis, characterization, and pharmaceutical potential evaluation of new biologically active Mn(II) and Cu(II) complexes with Schiff bases derived from sulfamethoxazole. The coordination mode of the complexes, geometry, and general formula were determined using elemental analysis, emission atomic spectroscopy, molar conductance, magnetic measurements, TGA, FTIR, electronic absorption spectroscopy, SEM-EDX, and EPR spectroscopy. The results indicate that the Schiff base act as bidentate ligands binding to the metal ions via the nitrogen atoms of the sulfonamide and oxazole groups which leads to a distorted octahedral geometry around the central metals.The in vitro antimicrobial properties of the Schiff base ligands and their respective Mn(II) and Cu(II) complexes were evaluated against Gram-negative and Gram-positive (Escherichia coli klebsiella pneumoniae, Staphylococcus aureus, and Bacillus subtilis)) bacteria, and two fungal strains (Candida albicans, Aspergillus niger). The results assert that the complexes display excellent antimicrobial properties with low MIC values. Additionally, DPPH-scavenging assay results suggest that the coordination compounds could act as efficient antioxidant species.The in vitro cytotoxicity assay conducted on chronic myelogenous leukaemia cell lines (K562) showed that the coordination compounds exhibit potent anticancer activities. Furthermore, the pharmaceutical properties, including pharmacokinetics and toxicity, were examined by ADMET simulations and molecular docking studies were employed to assess interactions between the complexes and drug targets. The in vitro experimental data and in silico computational analysis revealed that the ligands and their respective coordination compounds as noteworthy candidates for drug development.

Hydroxychavicol sensitizes imatinib-resistant chronic myelogenous leukemia cells to TRAIL-induced apoptosis by ROS-mediated IAP downregulation: Erratum.

Hydroxychavicol sensitizes imatinib-resistant chronic myelogenous leukemia cells to TRAIL-induced apoptosis by ROS-mediated IAP downregulation: Erratum.

Biochips to measure ultraviolet light absorption by leukemia cells

During the treatment of leukemia, side effects create a great burden for patients. Therefore, new therapies to replace conventional chemotherapy and hematopoietic stem cell transplantation are highly desirable. In a previous study, I found that UV irradiation at 365 nm induced apoptosis in 98% of leukemia (Jurkat T) cells. To determine the most suitable wavelength for such treatments, it is necessary to measure the UV light absorption of cancer cells. In this study, a biochip was fabricated and evaluated for this purpose. Three types of leukemic cells (human acute myelogenous leukemia cells, human acute lymphoblastic leukemia cells, and human chronic myelogenous leukemia cells) were injected into the biochip, and light absorption was measured, revealing that individual leukemic cells have different light absorption characteristics. This variation is important in order to develop an implant care device to treat leukemia more effectively.

Evaluation the Anti-leukemia effect of Methanol extracts of Camellia cuongiana on the K562 cell line

This study aims to examine the anti-proliferation effects of Camellia cuongiana methanolic extracts on the K562 chronic myelogenous leukaemia cell line. The crude extract was obtained by soaking the sample with methanol, following concentration using a rotary evaporator. Trypan blue exclusion test was performed in five concentrations of extract to detect the anti-cancer characteristic of Camellia cuongiana. Morphological changes in the treatment cell were observed using a phase-contrast microscope. After 72 hours of treatment, the extracts inhibited cell proliferation, with IC50 values of 72.26±5.75µg/mL. Increasing the extract concentration decreased the number of living cells. The most frequently observed abnormal morphology was cell shrinkage. Evidently, Camellia cuongiana could inhibit cancer cell proliferation and induce programmed cell death.

Inhibition of LATS kinases reduces tumorigenicity and increases the sensitivity of human chronic myelogenous leukemia cells to imatinib

Chronic myelogenous leukemia (CML) is a clonal hematologic malignancy of the myeloid lineage caused by the oncogenic BCR/ABL fusion protein that promotes CML cell proliferation and protects them against drug-induced apoptosis. In this study, we determine LATS1 and LATS2 expression in CML cells derived from patients who are resistant to imatinib (IM) treatment. Significant upregulation of LATS1 and LATS2 was found in these CML patients compared to healthy donors. To further explore whether the expression of LATS1/2 contributes to the IM-resistant phenotype, IM-resistant CML cell lines generated by culturing CML-derived erythroblastic K562 cells in increasing concentrations of IM were used as in vitro models. Up-regulation of LATS1 and LATS2 was observed in IM-resistant K562 cells. Reduction of LATS using either Lats-IN-1 (TRULI), a specific LATS inhibitor, or shRNA targeting LATS1/2 significantly reduced clonogenicity, increased apoptosis and induced differentiation of K562 cells to late-stage erythroid cells. Furthermore, depletion of LATS1 and LATS2 also increased the sensitivity of K562 cells to IM. Taken together, our results suggest that LATS could be one of the key factors contributing to the rapid proliferation, reduced apoptosis, and IM resistance of CML cells. Targeting LATS could be a promising treatment to enhance the therapeutic effect of a conventional BCR/ABL tyrosine kinase inhibitor such as IM.

Effect of Extracellular Vesicles Derived From Peripheral Blood Mononuclear Cells on K562 Leukemia Cell Line

Recently, extracellular vesicles (EVs) are generating considerable interest in terms of their ability. EVs defined themselves as a route for intercellular communication between the origin cells and the recipient ones by transferring information. This paper investigates the influence of peripheral blood mononuclear cells derived EVs on proliferation and apoptosis of the chronic myelogenous leukemia cell line k562. Trypan blue staining was used to detect cell viability subsequently, metabolic activity was assessed by the MTT assay. Cell apoptosis and cell cycle progression were evaluated using flowcytometric assay after treatment of k562 cell line with MNC derived EVs. Our results showed that MNC-EVs have no inhibitory effect on k562 cell growth and proliferation. Our data did not reveal any significant variations in the case of enhancing k562 cell line growth following treatment with MNC derived EVs. It seems tumour-derived extracellular vesicles support tumour cells growth by communicating with each other through their extracellular vesicles.

SiRNA-mediated downregulation of BATF3 diminished proliferation and induced apoptosis through downregulating c-Myc expression in chronic myelogenous leukemia cells.

Despite considerable improvement in therapeutic approaches to chronic myeloid leukemia (CML) treatment, this malignancy is considered incurable due to resistance. However, investigating the molecular mechanism of CML may give rise to the development of extremely efficient targeted therapies that improve the prognosis of patients. Basic leucine zipper transcription factor ATF-like3 (BATF3), as transcription factor, is considered a key regulator of cellular activities and its function has been evaluated in tumor development and growth in several cancer types. This study aimed to evaluate the potential of the cellular impact of siRNA-mediated downregulation of BATF3 on CML cancer cells through cell proliferation, induction of apoptosis, and cell cycle distribution. The transfection of BATF3 siRNA to K562 CML cells was performed by electroporation device. To measure cellular viability and apoptosis, MTT assay and Annexin V/PI staining were carried out, respectively. Also, cell cycle assay and flow cytometry instrument were applied to assess cell cycle distribution of K562 cells. For more validation, mRNA expression of correlated genes was relatively evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). The data indicated that siRNA-mediated BATF3 inactivating severely promoted the cell apoptosis. Also, the targeted therapy led to high expression of Caspase-3 gene and Bax/Bcl-2 ratio. Silenced BATF3 also induced cell cycle arrest in phase sub-G1 compared to control. Finally, a noticeable decrement was obtained in c-Myc gene expression through suppression of BATF3 in CML cells. The findings of this research illustrated the suppression of BATF3 as an effective targeted therapy strategy for CML.

L‐lysine Janus Dendrimer Conjugate with Naproxen and Mefenamic Acid and its Anticancer Activity

AbstractDendritic architectures have potential use as excellent carriers for drug delivery due to their multifunctionality, biopermeability, and biodegradability properties. Furthermore, their conjugation with non‐steroidal anti‐inflammatory drugs (NSAIDs) results in a synergetic effect improving their anticancer activity. Here we report the synthesis and cytotoxic activity of novel Janus dendrimer conjugates with naproxen and mefenamic acid moieties at the periphery. Diethanolamine dendrons were convergently synthesized through a protection‐deprotection sequence with naproxen as a terminal group and finally coupled to triethylene glycol as a linker. On the other hand, mefenamic acid was covalently joined to the L‐lysine. The dendron and dendrimer‐conjugates with naproxen and mefenamic acid showed high inhibition and selectivity against PC‐3 (human prostatic adenocarcinoma), and K‐562 (human chronic myelogenous leukemia) cell lines, but low cytotoxicity against normal cell lines. To explain the molecular mechanisms involved in the anticancer activity of dendrimer conjugates, our research will be continued.

Apoptotic effect of Bulbine Natalensis and Chlorophytum Comosum in myelogenous Leukemia K562 cell line.

Bulbine natalensis and Chorophytum comosum are potential medicinal source for the treatment of cancers. Chronic myeloid leukaemia is a hematopoietic stem cells disorder treated by tyrosine kinase inhibitors but often cause recurrence of the leukaemia after cessation of therapy, hence require alternative treatment. This study determines the anti-cancer effect of leaf, root and bulb methanolic and aqueous extracts of B. natalensis and C. comosum in chronic human myelogenous leukaemia (K562) cell line by MTT, Hoechst bis-benzimide nuclear and annexin V stain assays. The root methanolic extract of B. natalensis and C. comosum showed a high cytotoxicity of 8.6% and 16.7% respectively on the K562 cell line at 1,000 μg/ml concentration. Morphological loss of cell membrane integrity causing degradation of the cell and fragmentation were observed in the root methanolic extract of both plants. A high apoptosis (p < 0.0001) was induced in the K562 cells by both leaf and root extracts of the C. comosum compared to the B. natalensis. This study shows both plants possess apoptotic effect against in vitro myelogenous leukaemia which contributes to the overall anti-cancer properties of B. natalensis and C. comosum to justify future therapeutic applications against chronic myelogenous leukaemia blood cancer.

Heteroleptic Copper(II) Complexes Containing an Anthraquinone and a Phenanthroline as Synthetic Nucleases and Potential Anticancer Agents

Two ternary copper(II) complexes with an anthraquinone and a N,N-heterocyclic donor, [Cu(dmp)(L)(H2O)](ClO4) (1), [Cu(bpy)(L)(dmso)](ClO4) (2), in which dmp = 2,9-dimethyl-1,10-phenanthroline, bpy = 2,2′-bipyridine, and HL = 1-hydroxyanthracene-9,10-dione were synthesized and fully characterized by conductivity, elemental, and spectral analyses (FTIR and UV-Vis; EPR and ESI-MS). The structure of 1 reveals that Cu(II) is bound to two oxygens of L, two nitrogens of dmp, and a molecule of water in the fifth position. In complex 2.1, Cu(II) is also pentacoordinated with an O-bonded dmso in the axial position. The presence of the heteroleptic complexes in solution was evidenced by ESI-MS, EPR in dmso solution and UV-Vis spectrophotometry. All complexes bind to CT-DNA with affinity constants of approximately 104. Complex 2 can nick plasmid DNA but no cleavage was performed by complex 1. The investigation of DNA interactions by spectrofluorimetry using ethidium bromide (EB) showed that it was displaced from DNA sites by the addition of the complexes. The complexes inhibited the growth of chronic myelogenous leukemia and human squamous carcinoma cells with low IC50 values, complex 1 being the most effective.

Hydroquinone-selected chronic myelogenous leukemia cells are sensitive to chloroquine-induced cytotoxicity via MCL1 suppression and glycolysis inhibition

Previous studies have provided evidence that repeated exposure to the benzene metabolite hydroquinone (HQ) induces malignant transformation and increases basal autophagy in the chronic myeloid leukemia (CML) cell line K562. This study explored the cytotoxicity of the autophagy inhibitor chloroquine (CQ) on parental and HQ-selected K562 (K562/HQ) cells. CQ triggered apoptosis in these cells independently of inhibiting autophagic flux; however, in K562/HQ cells, CQ-induced cytotoxicity was higher than in K562 cells. Mechanistically, CQ-induced NOXA upregulation led to MCL1 downregulation and mitochondrial depolarization in K562/HQ cells. MCL1 overexpression or NOXA silencing attenuated CQ-mediated cytotoxicity in K562/HQ cells. CQ triggered ERK inactivation to increase Sp1, NFκB, and p300 expression, and co-assembly of Sp1, NFκB, and p300 in the miR-29a promoter region coordinately upregulated miR-29a transcription. CQ-induced miR-29a expression destabilized tristetraprolin (TTP) mRNA, which in turn reduced TTP-mediated NOXA mRNA decay, thereby increasing NOXA protein expression. A similar mechanism explained the CQ-induced downregulation of MCL1 in K562 cells. K562/HQ cells relied more on glycolysis for ATP production than K562 cells, whereas inhibition of glycolysis by CQ was greater in K562/HQ cells than in K562 cells. Likewise, CQ-induced MCL1 suppression and glycolysis inhibition resulted in higher cytotoxicity in CML KU812/HQ cells than in KU812 cells. Taken together, our data confirm that CQ inhibits MCL1 expression through the ERK/miR-29a/TTP/NOXA pathway, and that inhibition of glycolysis is positively correlated to higher cytotoxicity of CQ on HQ-selected CML cells.