Apoptosis In Leukemia K562 Cells Research Articles

Effect of Hispidulin on Proliferation and Apoptosis of Leukemia K562 Cells by Up-Regulating IL-37

To investigate the effect and underlying mechanism of hispidulin on the proliferation and apoptosis of leukemia K562 cells. K562 cells were cultured in vitro and treated with 0, 5, 25 or 100 μmol/L hispidulin for 24 h. Cell proliferation and apoptosis were detected by CCK-8 and flow cytometry, respectively. Western blot was used to assess the expression of Bax, Bcl-2 and interleukin (IL)-37 proteins. Bone marrow mononuclear cells were extracted from 17 chronic myeloid leukemia patients and 21 healthy individuals by Ficoll-Hypaque density gradient method, and the expression of IL-37 protein was measured by Western blot. K562 cells with IL-37 overexpression or knockdown were constructed, and then treated with 0 or 100 μmol/L hispidulin for 24 h. Cell proliferation, apoptosis and protein expression of Bax and Bcl-2 were determined in the same way as above. After K562 cells were treated with hispidulin, the cell inhibition rate, apoptosis rate, and the protein expression of Bax and IL-37 were significantly increased (P <0.05), but the cell proliferation and expression of Bcl-2 protein were decreased (P <0.05). The expression of IL-37 protein in bone marrow mononuclear cells of the leukemia patient was 0.24±0.03, which was significantly lower than 0.91±0.05 of healthy controls (P <0.05). Overexpression of IL-37 significantly promoted inhibition rate, apoptosis rate, and expression of Bax protein in K562 cells (P <0.05), but suppressed the expression of Bcl-2 protein (P <0.05). In addition, knockdown of IL-37 could reverse the effects of hispidulin on proliferation and apoptosis of K562 cells. Hispidulin inhibits the proliferation and induces apoptosis of leukemia K562 cells, which may be related to the up-regulation of IL-37 protein in cells.

Design and synthesis of new adamantyl derivatives as promising antiproliferative agents

A series of adamantyl carboxamide derivatives containing sulfonate or sulfonamide moiety were designed as multitargeted inhibitors of ectonucleotide pyrophosphatases/phosphodiesterases (NPPs) and carbonic anhydrases (CAs). The target compounds were investigated for their antiproliferative activity against NCI-60 cancer cell lines panel. Three main series composed of 3- and 4-aminophenol, 4-aminoaniline, and 5-hydroxyindole scaffolds were designed based on a lead compound (A). Compounds 1e (benzenesulfonyl) and 1i (4-fluorobenzenesulfonyl) of 4-aminophenol backbone exhibited the most promising antiproliferative activity. Both compounds exhibited a broad-spectrum and potent inhibition against all the nine tested cancer subtypes. Both compounds showed nanomolar IC50 values over several cancer cell lines that belong to leukemia and colon cancer such as K-562, RPMI-8226, SR, COLO 205, HCT-116, HCT-15, HT29, KM12, and SW-620 cell lines. Compounds 1e and 1i induced apoptosis in K-562 leukemia cells in a dose-dependent manner. Compound 1i showed the highest cytotoxic activity with IC50 value of 200 nM against HT29 cell line. In addition, compounds 1e and 1i were tested against normal breast cells (HME1) and normal skin fibroblast cells (F180) and the results revealed that the compounds are safe toward normal cells compared to cancers cells. Enzymatic assays against NPP1-3 and carbonic anhydrases II, IX, and XII were performed to investigate the possible molecular target(s) of compounds 1e and 1i. Furthermore, a molecular docking study was performed to predict the binding modes of compounds 1e and 1i in the active site of the most sensitive enzymes subtypes.

Targeted silencing of CDX2 gene with siRNA enhanced vincristine-induced inhibition of proliferation and induction of apoptosis of leukemia K562 cells

Purpose: To determine the effect of targeted silencing of CDX2 with siRNA on vincristine-induced inhibition of proliferation and apoptosis induction in leukemia K562 cells.&#x0D; Methods: K562 cells were divided into untreated group, vincristine group, blank group, and CDX2-siRNA group. The expression of CDX2 gene after CDX2-siRNA transfection was determined by reverse-transcription-polymerase chain reaction (RT-PCR) and immunoblotting, while MTT and flow cytometric procedures were used to evaluate the effect of vincristine on proliferation and apoptotic changes in K562 cells.&#x0D; Results: Protein expression of CDX2 did not change significantly in non-treated cells, vincristine group and blank group, while the expression of CDX2 protein in cells of CDX2-siRNA group was decreased significantly (p &lt; 0.05) while MTT assay results showed that the absorbance of CDX2-siRNA cells was significantly lower than those of the other three groups at 12, 24 and 48 h after CDX2 gene silencing. Flow cytometry showed markedly higher percentage apoptosis of CDX2-siRNA group than in other groups at 12, 24 and 48 h after CDX2 gene silencing. There was no difference in apoptosis level between vincristine group and blank group, but apoptosis was higher in these groups than in untreated group (p &lt; 0.05).&#x0D; Conclusion: Silencing CDX2 gene via targeting with siRNA enhances vincristine-induced suppression of growth and apoptotic changes in leukemia K562 cells, thereby enhancing the anti-tumor effect of vincristine.

Antioxidant and Anticancer Activities of Synthesized Methylated and Acetylated Derivatives of Natural Bromophenols.

Natural bromophenols are important secondary metabolites in marine algae. Derivatives of these bromophenol are potential candidates for the drug development due to their biological activities, such as antioxidant, anticancer, anti-diabetic and anti-inflammatory activity. In our present study, we have designed and synthesized a series of new methylated and acetylated bromophenol derivatives from easily available materials using simple operation procedures and evaluated their antioxidant and anticancer activities on the cellular level. The results showed that 2.,3-dibromo-1-(((2-bromo-4,5-dimethoxybenzyl)oxy)methyl)-4,5-dimethoxybenzene (3b-9) and (oxybis(methylene))bis(4-bromo-6-methoxy-3,1-phenylene) diacetate (4b-3) compounds ameliorated H2O2-induced oxidative damage and ROS generation in HaCaT keratinocytes. Compounds 2.,3-dibromo-1-(((2-bromo-4,5-dimethoxybenzyl)oxy)methyl)-4,5-dimethoxybenzene (3b-9) and (oxybis(methylene) )bis(4-bromo-6-methoxy-3,1-phenylene) diacetate (4b-3) also increased the TrxR1 and HO-1 expression while not affecting Nrf2 expression in HaCaT. In addition, compounds (oxybis(methylene)bis(2-bromo-6-methoxy-4,1-phenylene) diacetate (4b-4) inhibited the viability and induced apoptosis of leukemia K562 cells while not affecting the cell cycle distribution. The present work indicated that some of these bromophenol derivatives possess significant antioxidant and anticancer potential, which merits further investigation.

Vitexin isolated from Prosopis cineraria leaves induce apoptosis in K-562 leukemia cells via inhibition of the BCR-ABL-Ras-Raf pathway.

Leukemia is one of the severe cancer types all around the globe. Even though some chemotherapeutic drugs are available for treating leukemia, they have various side effects. As an alternative approach, herbal drugs are focused on current research to overcome leukemia. The present work was conducted to investigate the antileukemic mechanism of active phytochemical vitexin, which was isolated from ethno-medicine (Prosopis cineraria leaf) used by traditional healers of West Bengal, India. Antiproliferative mechanisms of selected phyto-compound against K-562 cells were evaluated using cellular uptake, morphological changes, DNA fragmentation, mitochondrial membrane potential and signaling pathways analysis. Vitexin exhibited cytotoxicity by reducing mitochondrial membrane potential (32.40%) and causing DNA fragmentation (84.15%). The western blotting study indicated inhibition of cell survival proteins (BCR, ABL, H-RAS, N-RAS, K-RAS and RAF) and expression of apoptotic proteins (p38, BAX and caspase-9) in leukemia cells upon treatment with vitexin. Based on the results, presently investigated phyto-compound vitexin could be considered for developing safe and natural drugs to treat leukemia after conducting suitable preclinical and clinical trials.

10-(4-Phenylpiperazine-1-carbonyl)acridin-9(10H)-ones and related compounds: Synthesis, antiproliferative activity and inhibition of tubulin polymerization

As part of our continuing search for potent inhibitors of tubulin polymerization, two novel series of 42 10-(4-phenylpiperazine-1-carbonyl)acridin-9(10H)-ones and N-benzoylated acridones were synthesized on the basis of a retrosynthetic approach. All newly synthesized compounds were tested for antiproliferative activity and interaction with tubulin. Several analogs potently inhibited tumor cell growth. Among the compounds tested, 10-(4-(3-methoxyphenyl)piperazine-1-carbonyl)acridin-9(10H)-one (17c) exhibited excellent growth inhibitory effects on 93 tumor cell lines, with an average GI50 value of 5.4 nM. We were able to show that the strong cytotoxic effects are caused by disruption of tubulin polymerization, as supported by the EBI (N,N'-Ethylenebis(iodoacetamide)) assay and the fact that the most potent inhibitors of cancer cell growth turned out to be the most efficacious tubulin polymerization inhibitors. Potencies were nearly comparable or superior to those of the antimitotic reference compounds. Closely related to this, the most active analogs inhibited cell cycling at the G2/M phase at concentrations down to 30 nM and induced apoptosis in K562 leukemia cells. We believe that our work not only proves the excellent suitability of the acridone scaffold for the design of potent tubulin polymerization inhibitors but also enables synthetic access to further potentially interesting N-acylated acridones.

Emodin and AZT synergistically inhibit the proliferation and induce the apoptosis of leukemia K562 cells through the EGR1 and the Wnt/β‑catenin pathway.

The aim of the present study was to investigate the synergistic antitumor effects of emodin and 3'‑azido‑3'‑deoxythymidine (AZT) on human chronic myeloid leukemia cells and to explore the possible underlying mechanisms. The K562 cells were treated with emodin and AZT, and the rates of cell inhibition and apoptosis were determined by MTT assay and flow cytometry, respectively. The mRNA expression of EGR1 was detected by reverse transcription‑polymerase chain reaction (RT‑PCR) analysis. The expression of EGR1 was silenced using siRNA, and then protein expression of β‑catenin was detected by western blotting. The results demonstrated that AZT enhanced the inhibitory effect of emodin in K562 cells. The IC50 of the emodin/AZT combination at 24, 48 or 72h was 23.6/235.6, 10.2/101.6 or 5.9/58.5µmol/l, respectively, which was significantly lower compared with the IC50 of emodin (all >32µmol/l) or AZT (all >320µmol/l) alone. There was a dose‑dependent response to the combined emodin and AZT treatment, and the calculation of the combination index yielded values <1, demonstrating the synergistic effect of the combined treatment compared with the control (P<0.05). Furthermore, the combination of emodin and AZT increased apoptosis in K562 cells (P<0.05). Apoptosis was higher in the combination group compared with that of either treatment alone or control groups. The expression of early growth response‑1 (EGR1) in K562 cells was upregulated in a time‑dependent manner. The expression of EGR1 was higher in the combination group compared with that in the emodin or AZT alone groups. The expression of the Wnt/β‑catenin signaling pathway in the combination group was lower compared with that in the emodin or AZT alone groups. The expression of the Wnt/β‑catenin signaling pathway was significantly increased following EGR1 siRNA transfection. These data suggest that treating K562 cells with a combination of emodin and AZT exhibits reduced toxicity and improves therapeutic efficacy, and that the growth, inhibition, apoptosis and regulation of the Wnt/β‑catenin signaling pathway in human chronic myeloid leukemia cells by emodin and AZT may be associated with the expression of EGR1.

Knockdown of NUDT21 inhibits proliferation and promotes apoptosis of human K562 leukemia cells through ERK pathway.

BackgroundNUDT21 is a mammalian precursor mRNA(pre-mRNA) 3’ end processing factor and plays an important role in the selection of poly(A) sites in 3’-untranslated region (3’-UTR). NUDT21 links alternative polyadenylation with regulation of glioblastoma and osteosarcoma progression and is found to be related to drug resistance in childhood acute leukemia. However, the effect of NUDT21 on leukemia cells and the underlying mechanism are unknown.MethodsWe knocked down NUDT21 in K562 cells and applied qRT-PCR and western blotting to quantitate the mRNA and protein expression. Cell proliferating and apoptosis were investigated subsequently by flow cytometry, BrdU, Caspase3/7. RNA microarray and intracellular signaling array were used to determine the important cell signaling pathways.ResultsWe clarified that the mRNA expression levels of NUDT21 are higher in primary chronic myelocytic leukemia patients and K562 leukemic cells compared with healthy controls and PBMCs. Downregulation of NUDT21 expression in K562 cells inhibits proliferation and promotes apoptosis. Screening by mRNA chip and intracellular signaling array, we found that MAPK/ERK pathway represented the main molecular mechanism underlying the effects of NUDT21 knockdown in K562 cells.ConclusionNUDT21 played an important role in promoting proliferation and inhibiting apoptosis in leukemia K562 cells. The underlying mechanisms involved the modulation of PTEN and a set of downstream molecules including ERK1/2.Impact statementThe present work shows that the expression of NUDT21 was upregulated in chronic myelocytic leukemia and K562 cells. Silencing NUDT21 inhibited the proliferation and promoted the apoptosis of K562 cells. Subsequent experiments confirmed that NUDT21 promoted K562 proliferation through regulating the expression of p-ERK. Our findings may provide insights into the molecular mechanism underlying the effects of NUDT21 on leukemia cells and a novel strategy for the treatment of leukemia.

Cytotoxicity, oxidative stress, and apoptosis in K562 leukemia cells induced by an active compound from pyrano-pyridine derivatives.

Recent studies have reported the potential of pyrano-pyridine compounds in inhibiting cell growth and apoptosis induction in cancer cells. Here, we investigated the effect of new pyrano-pyridine derivatives on proliferation, oxidative damages, and apoptosis in K562 leukemia cells. Among different tested compounds, we found 8-(4-chlorobenzylidene)-2-amino-4-(4-chlorophenyl)-5, 6, 7, 8-tetrahydro-6-phenethyl-4H-pyrano-[3,2-c]pyridine-3-carbonitrile (4-CP.P) as the most effective compound with IC50 value of 20 μM. Gel electrophoresis, fluorescence microscopy, and flow cytometry analyses indicated the apoptosis induction ability of 4-CP.P in K562 cells. Further analyses revealed that 4-CP.P induces significant increase in cellular reactive oxygen species production, lipid peroxidation, protein oxidation, and total thiol depletion. Interestingly, while 4-CP.P significantly increased the activity of superoxide dismutase, it reduced the catalase activity in a time-dependent manner. These data propose that 4-CP.P treatment causes free radicals accumulation that ultimately leads to oxidative stress condition and apoptosis induction. Therefore, we report the 4-CP.P as a novel, potent compound as a chemotherapeutic agent in cancer treatment.

Effect of PKF118-310 on apoptosis of leukemia K562 cells and its mechanism

Objective To investigate the effect of small molecule antagonists PKF118-310 on apoptosis of human chronic myeloid leukemia cell line K562 and its mechanism. Methods After the treatment of PKF118-310 at different concentration, the proliferation inhibition in K562 cells was detected by MTT, the β-catenin/TCF transcription complex in the nucleus was observed by immunofluorescence, the apoptosis was detected by flow cytometry, and the expressions of caspase-3, caspase-8, XIAP, bcl-2, β-catenin, TCF, c-myc and cyclin D1 were detected by Western blot. Results PKF118-310 inhibited the proliferation of K562 cells. The median inhibitory concentration (IC50) of PKF118-310-treated K562 cells for 24 h, 48 h and 72 h were 5.388, 3.290, 1.566 μmol/L, respectively. The β-catenin/TCF transcription complex in the nucleus was observed. After the treatment with 1.6 and 3.2 μmol/L PKF118-310 for 48 h, the apoptosis rates of K562 cells were (48.0±0.9) % and (80.2±1.2) %, respectively, and were higher than that in the control group [(1.2±0.6) %] (both P < 0.05). After the treatment of K562 cells with PKF118-310 at different concentration for 72 h, the expression levels of caspase-3 and caspase-8 were increased (both P < 0.05), and the expression levels of XIAP, bcl-2, β-catenin, TCF, c-myc and cyclin D1 were significantly decreased compared with control group (all P< 0.05). Conclusion PKF118-310 can inhibit K562 cells'proliferation, and induce the apoptosis. Key words: Leukemia, myeloid, chronic; K562 cells; Wnt/β-catenin signaling pathway; PKF118-310; Apoptosis

Hypericin-mediated photodynamic therapy induces apoptosis in K562 human leukemia cells through JNK pathway modulation.

Hypericin (Hyp) is traditionally used as an antidepressant and antiviral agent. It selectively accumulates in spheroids and is also used as a photosensitizer in the photodynamic therapy of cancer. The present study aimed to investigate the cytotoxic effect of Hyp-mediated photodynamic therapy (Hyp-PDT) on cell growth and apoptosis of K562 leukemia cells, and to examine the underlying mechanisms. Hyp-PDT was performed with different light intensities (0.1, 0.3 and 0.5 mW/cm2), different concentrations of Hyp (0, 0.2, 0.4 and 0.8 µg/ml) and different durations of irradiation (0, 2, 4 and 8 min) in order to select the optimal conditions for subsequent experiments. A concentration of 0.4 µg/ml Hyp with a 5 h drug-light interval and 4 min irradiation at 0.3 mW/cm2 light intensity was selected as the optimal conditions. The effects of Hyp-PDT on apoptosis were determined by detecting morphological changes under microscopy and by performing western blot analysis. The results revealed that Hyp-PDT suppressed cell viability in a light intensity-, dose- and irradiation duration-dependent manner. The expression levels of cleaved caspase-9, cleaved caspase-3 and phosphorylated-C-Jun N terminal kinase (JNK) l were significantly upregulated following Hyp-PDT. These results indicated that Hyp-PDT decreased cell viability and induced mitochondria-caspase-dependent apoptosis in the K562 cells through regulation of the JNK pathway. These findings suggest that Hyp-PDT may be developed as an effective treatment for leukemia.

A comparative proteomic study of Homoharringtonine-induced apoptosis in leukemia K562 cells

The objective of this study was to determine the changes in protein profiles of K562 chronic myeloid leukemia (CML) cells in response to Homoharringtonine (HHT). HHT treatment significantly increased apoptosis of K562 cells. Proteomic analyses indicated 32 differentially expressed proteins, 13 of which were identified by mass spectrometry (nine down-regulated and four up-regulated). Aside from alterations in apoptotic proteins and proteins associated with transcription and translation, our data also revealed changes in oxidative stress response and redox reaction-related proteins, such as heat shock proteins (Hsps), DJ-1 and thioredoxin. Specifically, these proteins were validated to decrease after HHT treatment in K562 cells and in primary CML cells by immunoblot analysis. Additionally, Hsps, DJ-1 and thioredoxin, which were also shown to decrease in primary cells from imatinib-resistant patients, may be promising potential targets for mechanistic research and new clinical treatments.

Apoptosis of K562 leukemia cells by Abnobaviscum F®, a European mistletoe extract

Evidence suggests that mistletoe extract has the potential to be used as an anticancer agent. AbnobaviscumF® is a European mistletoe extract from the host tree Fraxinus. We investigated the effect of AbnobaviscumF on the growth and survival of different leukemia cell lines. AbnobaviscumF treatment strongly reduced survival and induced apoptosis of K562 (human myeloid leukemia), RPMI-8226 (human plasmacytoma) and L1210 (murine lymphocytic leukemia) cells in culture. Using K562 cells to further investigate the mechanism of action of AbnobaviscumF, we showed that AbnobaviscumF-induced cell death was associated with the activation of caspase-9, JNK-1/2 and p38 MAPK, as well as with the downregulation of Mcl-1, and inhibition of ERK-1/2 and PKB phosphorylation. Moreover, AbnobaviscumF treatment led to both a reduction of cellular glutathione (GSH) and the induction of ER stress (GRP78 and CHOP induction and eIF-2α phosphorylation). By contrast, AbnobaviscumF did not impact the expression of the DR4 and DR5 death receptors. The AbnobaviscumF-induced apoptosis of K562 cells was blocked by pretreatment with either GSH, z-VAD-fmk or SP600125. Our results, therefore, show that AbnobaviscumF induces apoptosis of K562 cells through the activation of the intrinsic caspase pathway, the phosphorylation of JNK-1, the reduction of cellular GSH, and the induction of ER stress.

Synadenium umbellatum Pax. promotes cell cycle arrest and induces apoptosis in K-562 leukemia cells

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disease that shows apoptosis resistance. The introduction of imatinib mesylate has revolutionized the treatment of CML, but imatinib resistance may develop at any time and inevitably leads to disease progression. Synadenium umbellatum Pax. belongs to the Euphorbiaceae family and is popularly used in Brazil for the treatment of cancer. The cytotoxicity of Euphorbiaceae is associated with the ability of these plants and their bioactive compounds to induce apoptotic tumor cell death. Therefore, we aimed to investigate the cytotoxicity and the mechanisms of death induced by S. umbellatum extract in leukemic cells. S. umbellatum cytotoxicity was evaluated by trypan blue exclusion assay and flow cytometric analysis of the cell cycle; the mechanisms involved in K-562 cell death were investigated by light microscopy and flow cytometry. The results demonstrate that S. umbellatum is cytotoxic to leukemic cells in a concentration-dependent manner. Morphological analysis revealed that S. umbellatum treatment induced K-562 cell death by an apoptotic pathway. Furthermore, data indicate ROS overproduction, alterations in mitochondrial membrane potential, phosphatidylserine externalization and activation of caspase 9. Taken together, the results demonstrate that S. umbellatum extract arrested the cell cycle and triggered apoptosis at several levels in K-562 cells.

Induction of Apoptosis in K562 Leukemia Cells Upon Exposure to a Derivative from 4-aryl-4H Chromenes Family

Induction of Apoptosis in K562 Leukemia Cells Upon Exposure to a Derivative from 4-aryl-4H Chromenes Family

Rab7b suppresses autophagy and induces apoptosis of K562 leukemic cells treated with homoharringtonine

Abstract 4884Homoharringtonine is an effective anti-leukemia medicine developed by Chinese. It has been found to induce differentiation and apoptosis of leukemia cells. However, the mechanism of its anti-leukemia function has not been fully understood. Rab is a kind of G protein of Ras superfamily and participates in endocytosis and exocytosis of protein transport process. In recent studies, some Rab proteins such as Rab7 are found to be associated with cellular autophagy and apoptosis. We previously identified a new small GTPase homologous to Rab7, named Rab7b, which is selectively expressed in promyeloid and monocytic cells and is localized to lysosome-associated compartments.To investigate the roles of Rab7b in acute myeloid leukemia, we used leukemia cell line K562 as a model in the present study. After treatment of K562 cells with various doses of HHT, cell viability and apoptosis were measured by MTT assay and Annexin V/PI staining respectively. Protein expression of LC3, a marker of autophagy, and caspase3, 9, ERK1/2,Akt were determined by Western blot analysis. Using stable gene transfection, several Rab7b variants, including Rab7b wild-type, active mutant Rab7b-Q67L and localization-deficient mutant Rab7b-ΔCC as well as Rab7b RNAi were transfected in to K562 cells and their roles in regulation of apoptosis in K562 leukemia cells induced by HHT were further evaluated.Our data showed that the viability of the K562 cells was greatly reduced by HHT treatment in a dose- and time- dependant manner. Treatment of the K562 with HHT significantly increases apoptosis in the cells as measured by Annexin V/PI staining. Using Western blot analysis, we further determined that the expression of caspase3, 9 was increased, and ERK1/2 augmented with Akt was suppressed in the cells treated with HHT. After suppressing autophagy with 3-MA, apoptosis was enhanced in the K562 cells treated with HHT. (p<0.05). By constitutively expression of Rab7B and variants in K562 cells, we found that the rate of apoptotic cells are much higher in the K562 cells transfected with Rab7b wild-type and Rab7b-Q67L variants, along with increased expression of caspase3, 9, ERK1/2 and decreased expression of Akt in the transfectants with Rab7b wild-type and active mutant Rab7b-Q67L.Our study suggests that HHT is able to suppress autophagy and enhance apoptosis in K562 leukemia cells in a caspase-dependent way, which is associated with suppression of Akt phosphorylation and upregulation of ERK1/2. Over-expression of Rab7b can enhance HHT induced apoptosis in K562 cells, which may also be associated with suppression of Akt phosphorylation and upregulation of ERK1/2. Taken together, our study elucidates a new recognition for the mechanism of HHT in anti-leukemia therapy and provides a new insight into understanding the relationship between autophagy and apoptosis in leukemia cells induced chemotherapy. Disclosures:No relevant conflicts of interest to declare.

16-Hydroxycleroda-3,13-dien-15,16-olide regulates the expression of histone-modifying enzymes PRC2 complex and induces apoptosis in CML K562 cells

Aims Histone modifications play central epigenetic roles in regulating the entire genome of the cell and cell proliferation. Herein, we investigated the effects of the natural compound, 16-hydroxycleroda-3,13-dien-15,16-olide (PL3), on the expressions of histone-modifying enzymes, and examined how it induces apoptosis in leukemia K562 cells. Main methods Cell proliferation was determined by an MTT assay, and histone-modifying enzyme gene expressions were investigated by a quantitative real-time PCR. Protein expressions were analyzed by a Western blot analysis. The histone H3K27 distribution was observed with immunofluorescence staining. To verify polycomb repressive complex 2 (PRC2) complex downstream gene expressions, a gene-expression array was performed to determine gene regulations. Key findings PL3 induced apoptosis and modulated many histone-modifying enzymes, especially the two PRC2 components, enhancer of zeste homolog 2 (EZH2) and suppressor of zeste 12 homolog (Suz12). Genes repressed by PRC2 were shown to be reactivated by PL3. Of these, 10 genes targeted by the PRC2 complex were identified, and expressions of 10 pro-/antiapoptotic genes were significantly regulated; these effects may have contributed to PL3-induced apoptosis in K562 cells. Regulation of other histone-modifying enzymes, including Aurora B, may also be involved in cell-cycle regulation. Significance Our data suggest that the induction of apoptosis by PL3 might partly occur through both a reduction in PRC2-mediated gene silencing and the reactivation of downstream tumor suppressor gene expressions. PL3 acts as a novel small-molecule histone modulator, which can potentially contribute to cancer chemotherapy singly or as a combined medication.

Induction of differentiation and apoptosis in K562 leukemia cells upon exposure to a derivative from 4-aryl-4H chromenes family

Induction of differentiation and apoptosis in K562 leukemia cells upon exposure to a derivative from 4-aryl-4H chromenes family

Gnidilatimonoein from Daphne mucronata induced differentiation and apoptosis in leukemia cell lines

Among various treatments, plants play a crucial role in cancer chemotherapy. Base on literature data, different species of the thymeleaeceae family have been found to be good sources for anticancer agents. Therefore, our laboratory has initiated a research project on evaluating the anticancer properties of the Iranian medical plant, Daphne mucronata (Thymeleaeceae). Gnidilatimonoein is a new diterpene ester compound that is purified from Daphne mucronata with antiproliferative and anti-metastatic effects in different tumor cell lines. Based on the inhibitory role of this agent on the cell cycle progression of K562 cell line, we were interested to check gnidilatimonoein for induction of differentiation and apoptosis in different human leukemia ML-1, HL-60 and K562 cells. Cell viability was determined by trypan blue exclusion method. Cell differentiation was studied in terms of morphology, NBT reduction in leukemia cells (HL-60 and ML-1) and benzidine staining in erythroleukemia (K562) cells. Apoptosis was detected by fluorescence microscopy (Acridine orange/Ethedium bromide double staining), annexineV flow cytometry and DNA electrophoresis. After 48 hours of treatment with 10 µM gnidilatimonoein, 80-70% of HL-60 and ML1 cells showed NBT reduction. Indeed gnidilatimonoein induced monocyte differentiation of myeloid leukemia HL-60 and ML-1 cells but not K562 erythroluekemia cells. In this condition, we observed the growth inhibitory effect (60%) without substantial loss of viability (

Synergistic effect of magnetic nanoparticles of Fe3O4 with gambogic acid on apoptosis of K562 leukemia cells

Gambogic acid (GA) has a significant anticancer effect on a wide variety of solid tumors. Recently, many nanoparticles have been introduced as drug-delivery systems to enhance the efficiency of anticancer drug delivery. The aim of this study was to investigate the potential benefit of combination therapy with GA and magnetic nanoparticles of Fe(3)O(4) (MNPs-Fe(3)O(4)). The proliferation of K562 cells and their cytotoxicity were evaluated by MTT assay. Cell apoptosis was observed and analyzed by microscope and flow cytometry, respectively. Furthermore, real-time polymerase chain reaction and Western blotting analyses were performed to examine gene transcription and protein expression, respectively. The results showed that MNPs-Fe(3)O(4) dramatically enhanced GA-induced cytotoxicity and apoptosis in K562 cells. The typical morphological features of apoptosis treated with GA and MNPs-Fe(3)O(4) were observed under an optical microscope and a fluorescence microscope, respectively. The transcription of caspase-3 and bax gene in the group treated with GA and MNPs-Fe(3)O(4) was higher than that in the GA-alone group or MNPs-Fe(3)O(4)-alone group, but the transcription of bcl-2, nuclear factor-kappaB, and survivin degraded as did the expression of corresponding proteins in K562 cells. Our data suggests a potential clinical application of a combination of GA and MNPs-Fe(3)O(4) in leukemia therapy.