Chronic Myelogenous Leukemia Cells Research Articles

MiR-124-3p Enhances the Sansitivity of Chronic Myelogenous Leukemia Cell K562-R to Imatinib by Targeting ABCA2

To investigate the effect and mechanism of miR-124-3p-targeing regulating ABCA2 on chronic myelogenous leukemia cell K562-R. CML cells with miR-124-3p-overexpression and ABCA2-over-expression as well as subcutaneoustrans planted tumor nude mice were used as study objects. And the CML cells were divided into four groups: K562-R blank control, miR-124-3p mimic control, ABCA2-overexpression and mimic+PC ABCA2. The effects of miR-124-3p and ABCA2 on CML cells were analyzed. The levels of proliferation-, apoptosis- and autophagy- related protein were determined by Western blot. qRT-PCR was employed to detect the levels of miR-124-3p and ABCA2 in K562-R cells. The relationship between miR-124-3p and ABCA2 was validated by luciferase reporter system assays and bioinformatics. Hoechst/immunohistochemical staining and CCK-8 assay were performed to investigate the function involved. miR-124-3p highly expressed in K562-S cells and lowly expressed in K562-R cells, however, ABCA2 lowly expressed in K562-S cells and highly expressed in K562-R cells. Over-expression of miR-124-3p significantly decreased ABCA2 level and cell growth, but increased autophagy and apoptosis in K562-R cells (P＜0.01). When ABCA2 was over-expressed, the K562-R cell growth was promoted and autophagy and apoptosis were inhibited (P＜0.01). The miR-124-3p promoted cell autophagy and apoptosis but inhibited cell growth in nude mice transplant tumor model (P＜0.01). miR-124-3p can target ABCA2 to inhibit the growth of CML cells and promote the cell autophagy and apoptosis of CML cells.

ABL Genomic Editing Sufficiently Abolishes Oncogenesis of Human Chronic Myeloid Leukemia Cells In Vitro and In Vivo.

Chronic myelogenous leukemia (CML) is the most common type of leukemia in adults, and more than 90% of CML patients harbor the abnormal Philadelphia chromosome (Ph) that encodes the BCR-ABL oncoprotein. Although the ABL kinase inhibitor (imatinib) has proven to be very effective in achieving high remission rates and improving prognosis, up to 33% of CML patients still cannot achieve an optimal response. Here, we used CRISPR/Cas9 to specifically target the BCR-ABL junction region in K562 cells, resulting in the inhibition of cancer cell growth and oncogenesis. Due to the variety of BCR-ABL junctions in CML patients, we utilized gene editing of the human ABL gene for clinical applications. Using the ABL gene-edited virus in K562 cells, we detected 41.2% indels in ABL sgRNA_2-infected cells. The ABL-edited cells reveled significant suppression of BCR-ABL protein expression and downstream signals, inhibiting cell growth and increasing cell apoptosis. Next, we introduced the ABL gene-edited virus into a systemic K562 leukemia xenograft mouse model, and bioluminescence imaging of the mice showed a significant reduction in the leukemia cell population in ABL-targeted mice, compared to the scramble sgRNA virus-injected mice. In CML cells from clinical samples, infection with the ABL gene-edited virus resulted in more than 30.9% indels and significant cancer cell death. Notably, no off-target effects or bone marrow cell suppression was found using the ABL gene-edited virus, ensuring both user safety and treatment efficacy. This study demonstrated the critical role of the ABL gene in maintaining CML cell survival and tumorigenicity in vitro and in vivo. ABL gene editing-based therapy might provide a potential strategy for imatinib-insensitive or resistant CML patients.

Quantum dots functionalized with 3-mercaptophenylboronic acids as novel nanoplatforms to evaluate sialic acid content on cell membranes

Sialic acids (SAs) modulate essential physiological and pathological conditions, including cell-cell communication, immune response, neurological disorders, and cancer. Besides, SAs confer negative charges to cell membranes, also contributing to hemorheology. Phenylboronic acids, called as mimetic lectins, have been highlighted to study SA profiles. The association of these interesting molecules with the optical properties of quantum dots (QDs) can provide a deeper/complementary understanding of mechanisms involving SAs. Herein, we explored the thiol affinity to the QD surface to develop a simple, fast and direct attachment procedure to functionalize these nanocrystals with 3-mercaptophenylboronic acids (MPBAs). The functionalization was confirmed by fluorescence correlation spectroscopy and inductively coupled plasma spectrometry. The conjugate specificity/efficiency was proved in experiments using red blood cells (RBCs). A labeling >90% was found for RBCs incubated with conjugates, which reduced to 17% after neuraminidase pretreatment. Moreover, QDs-MPBA conjugates were applied in a comparative study using acute (KG-1) and chronic (K562) myelogenous leukemia cell lines. Results indicated that KG-1 membranes have a greater level of SA, with 100% of cells labeled and a median of fluorescence intensity of ca. 2.5-fold higher when compared to K562 (94%). Therefore, this novel QDs-MPBA conjugate can be considered a promising nanoplatform to evaluate SA contents in a variety of biological systems.

Complex transcriptional regulation of the BCL2L12 gene: Novel, active promoter in K562 cells.

The BCL2L12, one of the latest discovered members of the BCL2 family, has both pro- and anti-apoptotic roles that are cell-type-dependent. Its role in tumorigenesis is highly implicated. Sixty-three splice variants of this gene have been identified so far, with significant differences in expression patterns between various cancer cell lines. Presently, little is known regarding the regulation of expression of the BCL2L12 gene. For the vast majority of BCL2L12 gene splice variants, the 5'- and 3'-untranslated regions as well as their transcriptional regulation have not been determined yet. The aim of this study was to get insight into the regulation of the BCL2L12 gene transcription in human chronic myelogenous leukemia (K562) cell line. Our results point to the activity of novel transcription start site of the BCL2L12 gene and indicate that Sp1 and GATA-1 transcription factors could be involved in the regulation of BCL2L12 gene expression in K562 cells. The previously reported active promoter of BCL2L12 gene differs from the one we described in our study. If this novel BCL2L12 promoter is confirmed to be active in other malignancies, transcripts generated from this region could be considered as new cancer-specific biomarkers. The results of our study contribute to the better understanding of the transcriptional regulation of the BCL2L12 gene.

Novel curcumin derivatives as P-glycoprotein inhibitors: Molecular modeling, synthesis and sensitization of multidrug resistant cells to doxorubicin

The MDR1/P-glycoprotein (Pgp)/ABCB1 multidrug transporter is being investigated as a druggable target for antitumor therapy for decades. The natural product curcumin is known to provide an efficient scaffold for compounds capable of blocking Pgp mediated efflux and sensitization of multidrug resistant (MDR) cells to the Pgp transported drug doxorubicin (Dox). We performed molecular dynamics simulations and docking of curcumin derivatives into the Pgp model. Based on these calculations, a series of pyrazolocurcumin derivatives with predicted metabolic stability and/or improved binding affinity were proposed for synthesis and evaluation of MDR reversal potency against Dox selected K562/4 subline, a derivative of K562 human chronic myelogenous leukemia cell line. Compounds 16 and 19 which are both dimethylcurcumin pyrazole derivatives bearing an N-p-phenylcarboxylic amide substitution, were the most potent Pgp blockers as determined by intracellular Dox accumulation. Furthermore, at non-toxic submicromolar concentrations 16 and 19 dramatically sensitized K562/4 cells to Dox. Together with good water solubility of 16 and 19, these results indicate that the new pyrazolo derivatives of curcumin are a promising scaffold for development of clinically applicable Pgp antagonists.

Microfluidic Platform for the Isolation of Cancer-Cell Subpopulations Based on Single-Cell Glycolysis.

High rates of glycolysis in tumorshave been associated with cancer metastasis, tumor recurrence, and poor outcomes. In this light, single cells that exhibit high glycolysis are specific targets for therapy. However, the study of these cells requires efficient tools for their isolation. We use a droplet microfluidic technique developed in our lab, Sorting by Interfacial Tension (SIFT), to isolate cancer cell subpopulations based on glycolysis without the use of labels or active sorting components. By controlling the flow conditions on chip, the threshold of selection can be modified, enabling the isolation of cells with different levels of glycolysis. Hypoxia in tumors, that can be simulated with treatment with CoCl2, leads to an increase in glycolysis, and more dangerous tumors. The device was used to enrich CoCl2 treated MDA-MB 231 breast cancer cells from an untreated population. It is also used to sort K562 human chronic myelogenous leukemia cells that have either been treated or untreated with 2-deoxy-d-glucose (2DG), a pharmaceutical that targets cell metabolism. The technique provides a facile and robust way of separating cells based on elevated glycolytic activity; a biomarker associated with cancer cell malignancy.

EIF3b regulates the cell proliferation and apoptosis processes in chronic myelogenous leukemia cell lines via regulating the expression of C3G.

To investigate the functions of eIF3b in chronic myelogenous leukemia (CML). The expression of eIF3b was inhibited by transfecting aspecifically designed shRNA into the CML cell lines of TK-6 and K562. The CCK8 assay was conducted to determine cell viability, and flow cytometry was used to examine the change in the cell cycle and cell apoptosis. RNAsequencing was applied to screen the candidate targets of eIF3b to identify the underlying mechanisms of eIF3b.An in vivo tumour xenograft mouse model was established by injecting shRNA transfected cells into the NCG mice. The tumour size and body weight of mice were monitored every other day. The mice were sacrificed 2weeks after the tumour cell injection. The expression of eIF3b and target genes in the tumour tissues were determined by immunohistochemical staining and Western blotting. The group with inhibited expression of eIF3b led to about 50% lower cell viability compared with that of the control group (P < 0.05). Flow cytometry suggested that the percentage of increase in apoptotic cells was eight times higher than those in control group for TK-6 and K562 cells (P < 0.05). However, the difference between the cell amounts in the S phase for the experiment and control groups was not significant. After RNAsequencing and further validation via qPCR, C3G was screened as the potential target of eIF3b involved in the cell proliferation and apoptosis of CML cell lines. Subsequent in vivo analysis proved that the inhibition of eIF3b suppressed tumour formation and decreased C3G expression, thereby indicating that C3G was the potential target of eIF3b. eIF3b is correlated with the cell proliferation and cell apoptosis of CML. Moreover, eIF3b regulation most probably occurs via regulating the expression of C3G.

Identification and development of non-cytotoxic cell death modulators: Impact of sartans and derivatives on PPARγ activation and on growth of imatinib-resistant chronic myelogenous leukemia cells

4’-((2-Propyl-1H-benzo[d]imidazol-1-yl)methyl)-[1,1′-biphenyl]-2-carboxylic acid derived from telmisartan was identified as lead for the design of cell death modulators. In this study, we evaluated the efficacy of telmisartan itself and other sartans in combination with imatinib against K562-resistant cells. The findings were directly used to further optimize the lead structure. Telmisartan and candesartan cilexetil represented the most effective sartans, thus the influence of carboxyl/methyl carboxylate groups at positions 7 (compounds 6, 7) or 4 (compounds 12–14) at the benzimidazole core was studied. Additionally, according to the results of a former structure-activity study, telmisartan was transformed to the related amide (1). Telmisartan amide 1, as well as the esters 6 and 12 markedly sensitized the resistant CML cells to imatinib treatment. Correlation with their potency to activate PPARγ is not given. Candesartan cilexetil, telmisartan and 1 showed the profile of partial agonists at PPARγ with EC50 values of 4.2, 4.3 and 9.1 μM, respectively, while 6 and 12 caused only marginal intrinsic activation at 10 μM (Amax = 22% and 13%). However, the repression of the STAT5 phosphorylation relates with the possibility to sensitize K562-resistant CML cells to imatinib treatment. It is worth mentioning that all compounds were per se non-cytotoxic at relevant concentrations.

Deubiquitylase USP25 prevents degradation of BCR-ABL protein and ensures proliferation of Ph-positive leukemia cells.

Fusion genes resulting from chromosomal rearrangements are frequently found in a variety of cancer cells. Some of these are known to be driver oncogenes, such as BCR-ABL in chronic myelogenous leukemia (CML). The products of such fusion genes are abnormal proteins that are ordinarily degraded in cells by a mechanism known as protein quality control. This suggests that the degradation of BCR-ABL protein is suppressed in CML cells to ensure their proliferative activity. Here, we show that ubiquitin-specific protease 25 (USP25) suppresses the degradation of BCR-ABL protein in cells harboring Philadelphia chromosome (Ph). USP25 was found proximal to BCR-ABL protein in cells. Depletion of USP25 using shRNA-mediated gene silencing increased the ubiquitylated BCR-ABL, and reduced the level of BCR-ABL protein. Accordingly, BCR-ABL-mediated signaling and cell proliferation were suppressed in BCR-ABL-positive leukemia cells by the depletion of USP25. We further found that pharmacological inhibition of USP25 induced rapid degradation of BCR-ABL protein in Ph-positive leukemia cells, regardless of their sensitivity to tyrosine kinase inhibitors. These results indicate that USP25 is a novel target for inducing the degradation of oncogenic BCR-ABL protein in Ph-positive leukemia cells. This could be an effective approach to overcome resistance to kinase inhibitors.

Developing a biopolymeric chitosan supported Schiff-base and Cu(II), Ni(II) and Zn(II) complexes and biological evaluation as pro-drug

Chitosan derivatives are widely used as key classes of medicinal compounds owing to their non- toxic and biodegradable properties. So, in this work, to enhance chitosan biological activities, a new synthesis of a series of Schiff base and its metals complexes (Cu(II), Ni(II) and Zn(II)) of chitosan (CS) was prepared. Moreover, their physicochemical properties were characterized by IR, UV–Vis, SEM, melting point, thermo gravimetric analysis (TGA), X-ray diffraction (XRD), elemental analysis and 1H NMR techniques. Elemental analysis data confirmed the formation of chitosan-Schiff base as well as the coordination reaction with metals ions by increasing the carbon content caused by substitution. By elemental analysis, the degrees of acetylation (DA), deacetylation (DD) and substitution (DS) were acquired 23, 77.63 and 57.90%, respectively. Additionally, the 1H NMR spectroscopy was used for the determination of degree of deacetylation (DD) and Substitution (DS) of chitosan ranging from 87.5 and 85%, respectively. The presence of a new low-field signal at 10.23 ppm in the 1H NMR spectra confirmed the imine proton of Schiff base. The cytotoxicity of Chitosan, Chitosan-Schiff base and its metals complexes was tested against K562 chronic myelogenous leukemia (CML) and MG-63 (osteosarcoma cancer) cell lines by the MTT assay. The results suggested that the anticancer activity of Schiff base and their complexes was much better than that of pure CS against cancer MG63 cell line. Finally, through flow cytometry, we demonstrated that all compounds were efficient in inducing apoptosis effect in K562 and MG63 cell lines except Schiff base- chitosan in K562 cell lines.

Research Advance on Classic Wnt Pathway in Chronic Myelogenous Leukemia--Review

Abstract Chronic myelogenous leukemia (CML) is a hematological malignancy that seriously threatens the lives of patients. It was found that there are abnormal classic Wnt pathway, that is, Wnt/β-catenin signaling pathways in CML cells, moreover, Wnt/β-catenin signaling pathway is involved in the growth and proliferation of CML cells, and closely relates with the self-renewal ability of CML leukemic stem cells. This review summarizes the recent studies on the relationship between Wnt/β-catenin signaling pathway and CML, and the researches on the targeting inhibition of Wnt/β-catenin signaling pathway in CML treatment, thus to provide new ideas for the treatment of CML.

Research Advance on Classic Wnt Pathway in Chronic Myelogenous Leukemia--Review

Abstract Chronic myelogenous leukemia (CML) is a hematological malignancy that seriously threatens the lives of patients. It was found that there are abnormal classic Wnt pathway, that is, Wnt/β-catenin signaling pathways in CML cells, moreover, Wnt/β-catenin signaling pathway is involved in the growth and proliferation of CML cells, and closely relates with the self-renewal ability of CML leukemic stem cells. This review summarizes the recent studies on the relationship between Wnt/β-catenin signaling pathway and CML, and the researches on the targeting inhibition of Wnt/β-catenin signaling pathway in CML treatment, thus to provide new ideas for the treatment of CML.

Effects of Glycyrrhetic Acid on Human Chronic Myelogenous Leukemia Cells.

Chronic myelogenous leukemia (CML) is a type of blood cancer that is initially treated with imatinib (first Abl kinase inhibitor). However, some patients with CML develop imatinib resistance. Several new generation drugs have been developed, but do not overcome this problem. Glycyrrhetic acid (GA) is a plant-derived pentacyclic triterpenoid that exhibits multiple pharmacological properties for the treatment of cancers. The current study aimed to investigate the effects of GA on the K562 cell line (Bcr-Abl positive leukemia). The MTT cell proliferation assay was employed to evaluate the cytotoxic effect of GA compared with imatinib (positive control) against leukemia and normal blood cells. For detection of cell death, an apoptotic/necrotic/healthy assay was performed against the K562 cell line. To investigate the kinase inhibitory activity of GA, the Abl1 kinase profiling assay and a molecular docking study were performed. GA showed Abl kinase inhibitory activity with an IC50 value of 29.2 μM and induced apoptosis in the K562 cell line after 6 h of treatment. The current findings indicate that this class of plant extract could be a potential candidate for treatment of CML.

Kaempferol in reversing drug resistance of chronic myelogenous leukemia K562/ADM cells and its related mechanism

Objective To investigate the drug resistance of kaempferol reversed adriamycin (ADM)-resistant K562/ADM cells in chronic myelogenous leukemia (CML) and its related mechanism. Methods Methyl thiazolyl tetrazolium (MTT) method was used to detect the toxicity of ADM on K562 and K562/ADM cells for 24 h. The half inhibitory concentration (IC50) of ADM and the drug resistance multiple for 24 h were calculated. MTT method was used to detect the toxicity of kaempferol on K562/ADM cells for 24 h. The 5% inhibitory concentration (IC5) and 10% inhibitory concentration (IC10) of kaempferol for 24 h were calculated to determine the concentration of kaempferol in the subsequent experiments. And the cells untreated by the kaempferol were selected as the control group. The cell inhibition after the treatment of ADM for 24 h of the blank control group and kaempferol intervention group was detected by using MTT method. And then the cell inhibition for 24 h and ADM IC50 for 24 h in the above groups were calculated. The ratio of IC50 in the blank control group and kaempferol group was the reversal drug resistance multiple of kaempferol. The fluorescence intensity of ADM in K562/ADM cells treated by kaempferol was detected by using flow cytometry. Western blotting was used to detect the expressions of P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), phosphorylated p38 (p-p38), and total p38 (t-p38) protein in K562/ADM cells after the treatment of kaempferol, the specific inhibitor of p38-MAPK signaling pathway SB202190, and the combination of kaempferol and SB202190. Results After the treatment of ADM for 24 h, the IC50 value of K562 and K562/ADM cells was (0.9±0.6), (28.1 ±3.5) μg/ml, respectively. The drug resistance multiple of K562/ADM cells on the treatment of ADM for 24 h was 31.16 compared with the K562 cells. MTT method showed that kaempferol inhibited the proliferation of K562/ADM cells in a dose-dependent manner. According to the IC5 and IC10, 0.5 μmol/L and 1.0 μmol/L kaempferol were determined to do the subsequent experiments. After the combined interaction of kaempferol and ADM for 24 h, the ADM IC50 of K562/ADM cells in the blank control group, 0.5 μmol/L kaempferol group and 1.0 μmol/L kaempferol group was (33.7±5.7), (21.4±0.6), (15.9±1.8) μg/ml, respectively (F = 30.85, P 0.05); SB202190 could reduce the relative expressions of P-gp, MRP1 and p-p38 protein (all P 0.05). Conclusions Kaempferol can decrease the relative expressions of P-gp and MRP1 in K562/ADM cells by inhibiting p38-MAPK pathway, so as to increase the concentrations of ADM and to reverse the drug resistance of K562/ADM cells. Key words: Leukemia, myelogenous, chronic; Drug resistance, neoplasm; Kaempferol; Doxorubicin; P-glycoprotein; Multidrug resistance-associated protein 1; p38; MAP kinase; K562/ADM cells

Dinuclear copper(II) complex with a benzimidazole derivative: Crystal structure, theoretical calculations, and cytotoxic activity

This work describes a facile synthesis of 5,6‐dimethyl‐2‐(pyridin‐2‐yl)‐1‐[(pyridin‐2‐yl)methyl]‐1H‐benzimidazole (dppb) and the preparation of a dinuclear copper(II) complex bearing this ligand in a ring‐like conformation of formula [Cu(dppb)(acn)ClO4]2(ClO4)2·4acn (1), where acn represents acetonitrile. The crystal structure of the complex was determined by single‐crystal X‐ray diffraction experiment, which showed that dppb acts as a bridge in 1 due to its bidentate–monodentate μ‐κ2NN′:κN″coordination mode, and the coordination sphere of each metal center is completed by one acn molecule and one perchlorate ion. The structure of dinuclear copper(II) complex is symmetric and the two square–pyramidal copper(II) centers are separated by 5.381(1) Å. The geometry optimization, electronic structure, and vibrational spectrum of the [Cu(dppb)(acn)ClO4]22+ cation were calculated using the density functional theory method. The geometrical parameters obtained theoretically were remarkably similar to those observed in the crystal structure of 1 and the calculated vibrational frequencies are in satisfactory coherence with experimental data. In solution, the prepared complex can bind to DNA (Kb = 1.43 × 105 M−1) and inhibit the growth of a human chronic myelogenous leukemia cell line (K562) in a concentration‐dependent manner; importantly, it is almost four times more active than the corresponding free benzimidazole.

A novel series of chlorinated plastoquinone analogs: Design, synthesis, and evaluation of anticancer activity.

Herein, we report the synthesis and cytotoxic effects of novel chlorinated plastoquinone analogs (ABQ1-17) against different leukemic cells. Compounds ABQ3, ABQ11, and ABQ12 demonstrated a pronounced antiproliferative effect against chronic myelogenous leukemia (CML) K562 cell line with IC50 values of 0.82±0.07, 0.28±0.03, and 0.98±0.22μM, respectively. Among them, ABQ11 showed approximately three times higher selectivity than imatinib on CML. ABQ11-treated CML cells induced significant apoptosis at low concentration. Inhibitory effect of ABQ11 against eight different tyrosine kinases, including ABL1, was investigated. ABQ11 inhibited ABL1 with IC50 value of 13.12±1.71μM, indicating that the moderate inhibition of ABL1 kinase is just an in-part mechanism of its outstanding cellular activity. Molecular docking of ABQ11 into ABL1 kinase ATP-binding pocket revealed the formation of some key interactions. Furthermore, DNA cleavage assay showed that ABQ11 strongly disintegrated DNA at 1μM concentration in the presence of iron (II) complex system, assuming that the major mechanism for the anticancer effects of ABQ11 is DNA cleavage. In silico ADMET prediction revealed that ABQ11 is a drug-like small molecule with a favorable safety profile. Taken together, ABQ11 is a potential antiproliferative hit compound that exhibits unique cytotoxic activity distinct from imatinib.

Modification of multiwalled carbon nanotubes with a ruthenium drug candidate-indazolium[tetrachlorobis(1H-indazole)ruthenate(III)] (KP1019 ).

Functionalized carbon nanotubes are interesting, promising and unique delivery systems for anticancer drugs, which are now in the spotlight of nanomedicine. Connecting nanotubes with anticancer drugs or new compounds with anticancer properties aims at improving their stability, efficiency and reduces the toxic side effects of cancer treatment. In our research, we are interested in connecting functionalized MWCNTs-NH2 with [InH][trans-RuCl4(In)2], (KP1019) which is one of the most promising anticancer ruthenium(iii) drug candidates, known mainly as a cytotoxic agent for the treatment of platinum-resistant colorectal cancers. As a result of the amidation of MWCNTs (1), MWCNTs-NH2 (2) were obtained. Then, they were modified with [InH][RuCl4(In)2] (4) and the nanosystem [MWCNT-NH3+][RuCl4(In)2-] (3) was obtained. The characterization of the resulting products was performed using IR, Raman spectroscopy, thermal gravimetric, XRD, STEM-EDX, ESI-MS, ICP-MS, and XPS analyses. The cytotoxic activity has been tested on human lung carcinoma (A549), chronic myelogenous leukemia (K562) and human cervix carcinoma (HeLa) cells which showed the higher toxicity of the nanosystem than the ruthenium complex.

Diterpenoids from Roots of Salvia lachnocalyx; In-silico and In-vitro Toxicity against Human Cancer Cell Lines.

Further investigations on phytochemical constituents of dichloromethane extract from roots of Salvia lachnocalyx (S. lachnocalyx) led to the isolation and identification of eight known diterpenoids from this plant for the first time. The chemical structures of the purified compounds were elucidated using spectroscopic analyses including EI-MS, 1H and 13C NMR and by comparison of the resulting spectra with those reported in the literature. Then, the cytotoxic activity of identified compounds was examined against two human cancer cell lines MCF-7 (human breast adenocarcinoma) and K562 (human chronic myelogenous leukemia). Molecular docking of promising cytotoxic compounds were performed by AutoDock Tools 1.5.4 program in the active site of Topoisomerase I. Eight known diterpenoids; 12-hydroxysapriparaquinone (1), 15-deoxyfuerstione (2), horminon (3), 7α-acetoxyroyleanone (4), 11β-hydroxymanoyl oxide (5), microstegiol (6), 1-keto-aethiopinone (7) and 14-deoxycoleon U (8) were isolated of dichloromethane extract from roots of salvia lachnocalyx. Compounds 2, 3, 6, and 8 showed cytotoxic activity against MCF-7 (human breast adenocarcinoma) and K562 (human chronic myelogenous leukemia) cell lines with IC50 values in the range of 2.63-11.83 µg/mL. The inhibition of” topoisomerase I” was suggested by molecular docking calculations as the mechanism of cytotoxicity of the tested compounds. According to cytotoxic assay and docking results, it is suggested that compounds 2, 3, 6, and 8 have good potential as anticancer agents.

Effects of DNA Methylation on Leukemia Cell Proliferation.

In this study, we aimed to investigate the effect of DNA methyltransferase 1 gene (DNMT1) expression on leukemia cell proliferation. Following stimulation with interferon-α (IFN-α) or methylation inhibitor for three days, we evaluated changes in the DNMT1 expression levels, cell proliferation activity, and Bcl-2-Associated X Protein (BAX) expression levels in the chronic myelogenous leukemia cell line K562 and the acute monocytic leukemia cell line THP-1. DNMT1 expression levels and cell proliferation activity decreased in K562 and THP-1 cells, whereas BAX expression levels increased. These results suggest that the enzymatic activity of DNMT1 promotes the proliferation of tumor cells and that tumor cell proliferation can be suppressed by inhibiting DNMT1 enzymatic activity. Furthermore, because DNA methylation is associated with apoptosis, a process critical to cell growth and injury in leukemia, assessing DNMT1expression levels might help in treatment decisions for leukemia patients.

Investigating the cytotoxic and apoptotic effects of sunitinib upon K-562 chronic myelogenous leukemia cell line and assessment of gene profiling.

Tyrosine kinase inhibitors (TKIs) which efficiently inhibit BCR-ABL are highly effective for clinical treatment of chronic myeloid leukemia (CML), but development of resistance to TKIs is a big challenge to treatment. Sunitinib is a multitargeted TKI targeting vascular endothelial growth factor receptor and is defined a safe and effective candidate target, but its effect on other signaling pathways is unknown. To investigate the cytotoxic and apoptotic effect of sunitinib in CML cell model K-562 on JAK-STAT signaling pathway components, suppressor genes and oncogenes, hematopoiesis-related genes, cell cycle and VEGF pathway components, and mRNA level expression changes was aimed. Sunitinib's effective dose cytotoxic IC50 was determined by trypan blue and WST-1 cell proliferation assay tests. Expression levels of target genes were determined by quantitative reverse transcriptase polymerase chain reaction simultaneously after sunitinib application. Protein expression analysis was determined by "WesternBreeze Chromogenic Kit-Anti-Rabbit" based on the principles of the application kit by Western blot analysis. Assessing the cytotoxicity of K-562 cells following sunitinib treatment revealed that sunitinib decreased cell proliferation in a time- and dose-dependent manner. According to the sunitinib inhibition curve, IC50 dose was calculated as 3.5 μM at 48th h for K-562 cells and apoptosis assays pointed that sunitinib induces apoptotic cell death of leukemic cells at moderate levels. Our study supports that sunitinib might be used as a novel therapeutic target to trigger apoptosis in CML cells which in turn might accelerate therapeutic response in regard to inhibiting oncogenes and enhancing tumor suppressors in cooperation with cell cycle regulatory genes.