ZM-66, a New Podophyllotoxin Derivative Inhibits Proliferation and Induces Apoptosis in K562/ADM Cells

Objective To investigate the anti-tumor effect of ZM-66 on multidrug-resistant leukemic cell line K562/ADM. Methods The K562/ADM cells were treated with varying concentrations(0, 1, 2, 4×10-3 mmol/L) of ZM-66 or etoposide for 24 hours. The proliferation was detected by Sulforhodamine B Sodium Salt(SRB) assay and apoptosis was detected by flow cytometry analysis and fluorescent staining. In addition, the expression levels of p53 and bax genes in K562/ADM cells were detected by RT-PCR analysis. The level of P-glycoprotein(P-gp), P53 and Bax protein in K562/ADM cells were detected by Western blot assay. Results SRB assay demonstrated that etoposide had little inhibitory effect on K562/ADM cells, whereas ZM-66(1, 2, 4×10-3 mmol/L) had significantly inhibitory effect on K562/ADM cells(all P<0.01). The acridine orange/propidium iodide dual staining showed that there were typical condensation of chromatin and nuclear fragmentation nuclei with red color in ZM-66 treated cells. Flow cytometric analysis showed that there was a significantly increase of apoptotic cells in K562/ADM cells after treated with ZM-66. RT-PCR showed that the p53 and bax mRNA expression levels in K562/ADM cells treated with ZM-66 at 1, 2, 4×10-3 mmol/L were higher than those in the cell without treatment. Western blot showed that the P53 and Bax protein expression levels in K562/ADM cells treated with ZM-66 at 2, 4×10-3 mmol/L were higher than those in the cell without treatment. But the P-gp protein expression level in K562/ADM cells treated with ZM-66 at 2, 4×10-3 mmol/L was gradually lower than those in the cell without treatment. Conclusion ZM-66 is able to induce cell death by apoptosis in vitro, as a result of the reverse of theapoptosis resistance in drug-resistant K562/ADM cells by modulating expression of key factors associated with apoptosis induction.

Anti-cancer Effects of Deguelin on Human Leukemia K562 and K562/ADM Cells In Vitro

In order to investigate the anti-cancer effects of deguelin and on K562 and K562/ADM cells in vitro and the underlying molecular mechanism and compare the cytotoxicity of deguelin on K562, K562/ADM cells and human peripheral blood mononuclear cells （PBMCs）. The effects of deguelin on cell proliferation were assessed by MTT assay. Apoptosis were detected by Annexin V/PI double-labeled cytometry. The effects of deguelin on the cell cycle were studied by a propidium iodide method. Our study showed that deguelin inhibited the proliferation of K562 cell and K562/ADM cell in a time- and dose-dependent manner and had minimal effects on normal human peripheral blood mononuclear cells. The ratio of IC50 value of deguelin of 24 h on K562/ADM cells to K562 cells was only 1.27, which was significantly lower than the ratio of IC50 value of ADM （higher than 20）. Deguelin could induce apoptosis of K562 cells and K562/ADM cells. K562 cells were arrested at G2/M phase while K562/ADM cells were arrested at G0/G~ phase. Our results suggested that deguelin was a novel anti-leukemia agents with high efficacy and low toxicity and it is also a promising agent for reversing drug resistance.

Proteomics Study of Benzene Metabolite Hydroquinone Induced Hematotoxicity in K562 Cells

Objective Hydroquinone(HQ),one of the phenolic metabolites of benzene,is widely recognized as an important participant in benzene-induced hematotoxicity.However,there are few relevant proteomics in HQ-induced hematotoxicity and the mechanism hasn’t been fully understood yet.Methods In this study,we treated K562 cells with 40μmol/L HQ for 72 h,examined and validated protein expression changes by Label-free proteomic analysis and Parallel reaction monitoring(PRM),and performed bioinformatics analysis to identify interaction networks.Results One hundred and eighty-seven upregulated differentially expressed proteins(DEPs)and 279 downregulated DEPs were identified in HQ-exposed K562 cells,which were involved in neutrophilmediated immunity,blood microparticle,and other GO terms,as well as the lysosome,metabolic,cell cycle,and cellular senescence-related pathways.Focusing on the 23 DEGs and 5 DEPs in erythroid differentiation-related pathways,we constructed the network of protein interactions and determined 6 DEPs(STAT1,STAT3,CASP3,KIT,STAT5B,and VEGFA)as main hub proteins with the most interactions,among which STATs made a central impact and may be potential biomarkers of HQ-induced hematotoxicity.Conclusion Our work reinforced the use of proteomics and bioinformatic approaches to advance knowledge on molecular mechanisms of HQ-induced hematotoxicity at the protein level and provide a valuable basis for further clarification.

Arsenic Trioxide Inhibits Proliferation in K562 Cells by Changing Cell Cycle and Survivin Expression

To study the mechanisms involved in the inhibition of chronic myeloid leukemic cells (K562) proliferation induced by arsenic trioxide (As 2O 3) and to explore the potential role of Survivin, an inhibitor of apoptosis protein, in the regulation of As 2O 3 induced cell apoptosis, K562 cells were cultured with As 2O 3 of different concentrations. Cells were collected for proliferation analysis by MTT assay. Cell cycle distribution and cell apoptosis were analyzed by flow cytometry. Expression of Survivin protein and mRNA were detected by flow cytometry and RT-PCR, respectively. Our results showed that As 2O 3 (2-10 μmol/L) inhibited K562 cells growth effectively, but it did not induce cells apoptosis significantly. The percentage of K562 cells at G 2/M phase increased in proportion to As 2O 3 concentrations, and the expression of Survivin mRNA and content of Survivin protein was up-regulated accordingly. It is concluded that As 2O 3 inhibited K562 cells growth by inducing cell cycle arrest mainly at G 2/M phase. Over-expression of Survivin gene and protein might be one of the possible mechanisms contributing to K562 cells' resistance to As 2O 3-induced apoptosis.

INDEPENDENT AND SYNERGIC INHIBITION OF DIPYRIDAMOLE AND RADIATION ON K562-AND K562/ADM CELL LINES IN VITRO

It is first demonstrated that dipyridamole (DP) and radiation were capable of significantly inhibiting, independently and synerglcally, clonogenlc growth in the two kinds of K562 cell lines, adriamycin (ADM) -sensitive and ADM- resistant. DP or radiation alone Increased clonogenlc Inhibition rate (CIR) in the two kinds of cell lines in a dose- dependent fashion. DP potentiated radiosensitivity and radiation increased inhibition of DP in the two kinds of cell lines. K562/ ADM cell lines were higher sensitive to DP. radiation and combination of them than K562 cell lines (P<0. 01). There was stronger synergic inhibition of clonogenlc growth in the two kinds of cell lines when pretreated with DP than when posttreated with DP (P<0. 01).

Effect of Hydroxyapatitc Nanoparticles on K562 Cells in vitro

Stable and single-dispersed hydroxyapatite （HAP） nanoparticles were synthesized with ultrasonic-assisted method. HAP nanoparticles were characterized by dynamic light scattering, XRD （X-ray diffraction） and TEM （Transmission Electron Microscopy）. The effect of HAP nanoparticles on the K562 human myelogenous leukemia cell line was investigated by MTT assay and cell count test, and the mechanism was studied through the changes of cell cycle and ultrastructure. The results showed that HAP nanoparticles inhibited the proliferation of K562 cells dramatically in vitro. HAP nanoparticles entered the cytoplasm of K562 cells and the cells were arrested at G/M phase, thus, the cells died directly.

Effect on Proliferation and Erythroid Differentiation of K562 Cells by IER3IP1-Knockdown

Objective： To investigate the effect on erythroid differentiation and proliferation of K562 cells by IER3IP1-knockdown with RNA interference targeting at IER3IP1 gene. Methods： The shRNA eukaryotic expression vectors targeting at IER3IP1 gene were designed and constructed. Inhibitory effect was detected by semiquantitative RT-PCR. The impacts on K562 cells by RNAi were studied by MTT assay, benzidine staining, light microscope and electron microscopy observation, cell cycles analysis, colony formation assay and RT-PCR. The expressions of erythroid differentiation correlated genes Gfi-lB, GPA and 7-globin were studied after being exposed to 0.2μmol/L imatinib for two days. Results： The shRNA eukaryotic expression vectors were successfully constructed. The expression of IER3IP1 gene was significantly inhibited with an inhibition efficiency of 76% （P〈0.01）. Compared with the control groups, bcr/abl mRNA level was increased in K562/shRNA-IER3IP1 group （P〈0.01）. The proliferation ability was enhanced （P〈0.01） and the proportion of cells at G0/G1 phase decreased but S phase increased （P〈0.05） in K562/shRNA-IER3IP1 group. Under electron microscopy, the amount of euchromatin increased but heterochromatin decreased. There were structural abnomalities in endocytoplasmic reticulum and clusters of vesicular. The percentage of benzidine staining positive cells and mRNA expression levels of Gfi-1B, GPA and γ-globin were all decreased after being exposed to 0.2 μmol/L STI571 for two days in K562/shRNA-IER3IP1 group （P〈0.01）. Conclusion： IER3IP1-knockdown can hinder the erythroid differentiation and elevate the proliferation level of K562 cells. IER3IP1 may play a role in erythroid differentiation and proliferation of K562 cells.

Lethal Effect of Benzene Nitrogen Mustard Glucoside Derivate on K562 Cells

A new synthesized benzene nitrogen mustard was converted into glycosyl donor-trichloroacetimidate that was glycosylated with p-nitrophenol（glycosyl donors） to form β-lactosyl p-nitrobenzene under the protection of acetyl in a stereoselective manner, was prepared and evaluated for its cytotoxicity towards cultured K562 cell line. Methylthiazoy tetrazolium（MTT） assay, transmission electron microscopy（TEM）, flow cytometry（FCM） and immunohistochemistry were utilized to explore the mechanisms of how the compound arrests the growth of HCT-T cells. This new synthesed benzene nitrogen mustard glucoside derivate（BNMGD） presented a lower toxicity to normal cells, but is significantly more toxic to K562 cells compared with nitrogen mustard, meanwhile it can induce the apoptosis of K562 cells. These results indicate that the new synthesized BNMGD can inhibit the growth of K562 cells and induce the apoptosis, and its cytotoxicity towards cultured K562 cell line is much more effective than that of nitrogen mustard.

Zeylenone promotes apoptosis of chronic myelogenous leukemia-derived K562 cells by a mechanism involving Jak2 and src kinase

OBJECTIVE The present study was designed to investigate anticancer effect of zeylenone(Zey)on K562 cells derived from chronic myelogenous leukemia(CML)both in vitro and in vivo,followed by exploring the underlying mechanisms.METHODS Initially,the effects of Zey on cel viability,proliferation,and apoptosis were measured in K562 cells by MTT,soft agar assay,AO/EB staining,hoechst 33258 staining and flow cytometric analysis after they were treated with Zey for indicated time,the involving signaling pathways were then investigated by JC-1,real-time quantitative polymerase chain reaction(RT-q PCR),Western blotting and immunofluorescence analysis.Furthermore,the in vivo anti-tumoractivity of Zey was assessed with nude xenografts and the involving mechanism was confirmed by immunohistochemical(IHC)and histopathological analysis.RESULTS We identified that Zey dose-dependently decreased cell viability,colony formation and expression of Proliferating Cell Nuclear Antigen(PCNA),and significantly induced K562 cell apoptosis via regulating Bcl-2 family members,decreasing mitochondrial transmembrane potential,and activating caspase-3,caspase-9,and caspase-8(P<0.05 or P<0.01).Further study revealed that Zey significantly inhibited phosphorylation of Jak2 and Src and downregulated their downstream proteins,including stat3,PI3K/AKT/m TOR,and ERK1/2 signaling pathways(P<0.05 or P<0.01).Zey also suppressed tumor growth with low toxicity in mouse xenograft model of K562cells through decreasing expression of Jak2 and Src.CONCLUSION Our data demonstrated that Zey substantially suppressed K562 cells both in vitro and in vivo through Jak2 and Src pathways.These findings suggest the potential of Zey as an effective anticancer agent in CML treatment.

Suppression of Amino Acid Transporter LAT3 Expression on Proliferation of K562 Cells

The activity of the mTOR pathway is frequently increased in acute myeloid leukemia, and is tightly related with cellular proliferation. Leucine is tightly linked to the mTOR pathway and can acti- vate it, thereby stimulating cellular proliferation. LAT3 is a major transporter for leucine, and suppres- sion of its expression can reduce cell proliferation. Here, we show that suppression of LAT3 expression can reduce proliferation of the acute leukemia cell line, K562. We investigated the mRNA and protein expression of LAT3 in several leukemia cell lines and normal peripheral blood mononuclear cells （PBMNCs） using RT-PCR and Western blotting. We also evaluated cell viability using a methyl thia- zolyl tetrazolium （MTT） assay after blocking LAT3 expression with either shRNA targeted to LAT3 or a small molecular inhibitor BCH （2-aminobicyclo-（2,2,1）-heptane-2-carboxylic acid）. LAT3 mRNA and protein expression was detected in leukemia cell lines, but not in normal PBMNCs. Using K562 cells, it was found that cellular proliferation and mTOR pathway activity were significantly reduced when LAT3 was blocked with either shRNA or BCH. Our results suggest that leukemia cell proliferation can be sig- nificantly suppressed by blocking LAT3. This finding may lead to a new strategy to develop clinical therapy for the treatment of acute myeloid leukemia.

INDEPENDENT AND SYNERGIC INHIBITION OF VERAPAMIL AND ELECTRIC BEAM RADIATION ON CLONOGENIC GROWTH IN K562 AND K562／ADM CELL L

It was first reported here that verupamil(VP) and electric beam radiation(EBR) were capable of inhibiting,independently or synergically,clonogenic growth in two kinds of K562 cell lines, adriamycin(ADM)-sensitive and ADM-resistant(K562/S and K562/ADM).Results showed that clonogenic rate(CGR) decreased by 3%-99.9% in the prasence of dependent dose-ADM(3.8μg/ml) in K562/ADM cell lines,while treated with 0.5μM-6μM of VP.VP was capable of potentiating radiosensitivity in K562/S and K562/ADM cell lines,whether before or after exposure of them to electric beam radiation,and significantly reduced CGR in these kinds of cell lines(P<0.01).

In vitro antileukemia activity of ZSTK474 on K562 cells

Aim Chronic myelogenous leukemia （CML） is a hematopoietic stem cell cancer caused by the Bcr-Abl tyrosine kinase which arises from Philadelphia chromosome （Ph） translocation. Imatinib showed potent antitumor efficacy on CML but caused resistance, therefore, other chemotherapeutic drugs for CML are expected. Phosphati-dylinositol 3-kinases （PI3Ks） are lipid kinases that preferentially phosphorylate phosphatidylinositol 4,5-bisphos- phate （PIP2） to generate phosphatidylinositol 3,4,5-trisphosphate （PIP3） which activates the downstream Akt and mammalian target of rapamycin （mTOR） , and therefore play important roles in controlling signal pathways involved in cell proliferation, etc. ZSTK474, a specific PI3K inhibitor, was reported to show potent antitumor efficacy on various solid tumors, while the anti｜eukemia effect was not yet reported. Herein, the effects of ZSTK474 on K562 CML cells as well as the adriamycin-resistant human leukemia cells （K562/ADR） are reported. Methods Cell proliferation inhibition was detected by MTT assay. Cell cycle was analyzed by FACS. The expression of cell cycle related molecules like p27 and p21 was detected by western blot and qRT-PCR. Synergistic effect of ZSTK474 and Imatinib was evaluated by MTT assay and analyzed using Calcusyn. Results MTT assay showed that ZSTK474 could inhibit the proliferation of K562 and K562/ADR cells with ICs0 as 4 69 μmol · L^-1 and 7 57 μmol·L^-1 re- spectively. ZSTK474 induced cell cycle G1 arrest in the above two cell lines dose-dependently after 48 h treatment. Western blot analysis demonstrated ZSTK474 treatment decreased the level of cyclin D1 and increased the expres- sion of p27 and p21. Similar results in mRNA level were obtained by qRT-PCR assay. Combination of ZSTK474 and Imatinib indicated synergistic effect in both cell lines. Conclusion ZSTK474 exhibited anti-leukemia activity alone, and showed synergistic effect when combined with Imatinib, on CML K562 cells. These findings suggest possible application of ZSTK474 in CML treatment.

The Difference of Sensitivity between BXPC-3 and K562 Cells by Treatments with Combination of Indole-3-acetic Acid and Horseradish Peroxidase

The difference of sensitivity to indole- 3-acetic acid （ IAA ） combined with horseradish peroxidase （HRP） in K562 and BXPC- 3 cells was investigated. The cell proliferation was determined by MTF assay. The cell cycle and apoptosis of K562 and BXPC-3 cells were examined by a fluorescence flow cytometer （FCM） and terminal deoxynacleotidyl transferase-mediated dUTP nick-end labeling （TUNEL） respectively. The experimental results show that IAA and HRP could inhibit BXPC- 3 cell proliferation greatly compared with K562 cell during the first 48 h . The cell cycle was arrested predominantly at G2/ M phase in K562 and BXPC- 3 cells. The cell apoptosis of K562 and BXPC- 3 was induced by IAA/ HRP. There was a significant difference between the two cell lines since BXPC-3 cells were more sensitive than K562 cells by treatments with combination of IAA and HRP.

Antitumor Effect of Betulinic Acid on Human Acute Leukemia K562 Cells in vitro

The effects of betulinic acid (BA), a pentacyclic lupane-type triterpene, on the cell viability, cell cycle and apoptosis in human leukemia K562 cells were investigated. The effects of BA on the growth of K562 cells were studied by MTT assay. Apoptosis was assayed through Annexin V/propidium iodide (PI) double-labeled cytometry. The effects of BA on the cell cycle of K562 cells were studied by a PI method. The expression of Bax and capase-3 was detected by using Western blot. The results showed that BA was cytotoxic to K562 cells with an IC50 of 21.26 μg/mL at 24 h. After treating K562 cells with 10 μg/mL BA for 72 h, the number of cells was reduced by 58%. BA induced apoptosis of K562 cells in a time-and dose-dependent manner. The proportion of cells in G0/G1 and G2/M phases was decreased and that in S phase was increased after K562 cells were treated with BA for 24 h. BA treatment also increased the expression of the pro-apoptotic proteins Bax and caspase-3. It suggested that BA could inhibit the proliferation of K562 cells through the induction of cell cycle arrest and apoptosis. The antitumor effects of BA were related with up-regulation of the expression of Bax and caspase-3 proteins. BA may qualify for the development of new therapies for leukemia.

EFFECT OF BcL-2 ANTISENSE DRUG WITH DIFFERENT STRUCTURE ON THE BIOLOGICAL FUNCTION OF K562 CELLS

Objective: To study the differences and similarities of the antisense drugs with different structures on the biological functions of K562 cells. Methods: Cytotoxic effects were measured by use of a cell viability assay. Flow cytometric analysis and agarose gel electrophoresis of DNA fragmentation were also performed. The expression level of protein was assayed by immunofluorescence using fluoresce isothiocyanate label. Results: PNA targeting the coding region of the Bcl-2 messenger RNA could effectively inhibit K562 cell viability, down-regulate the synthesis of the Bcl-2 protein and increase cell apoptosis. By 72 h after the Bcl-2 antisense PNA treatment, K562 cells showed more reduction in the level of Bcl-2 protein compared with cells treated with the antisense ODN. After treatment with 10 μmol/L of Bcl-2 antisense PNA or antisense ODN for 72 h, apoptotic rates of K562 cells were 13.15±1.13 and 11.72±1.12, respectively. Furthermore, there was significant difference in the percentage of apoptotic cells between antisense PNA group and antisense ODN group. Conclusion: The results suggest that antisense PNA targeting the coding region of Bcl-2 mRNA has better antisense effects than the antisense oligonucleotides on inducing apoptosis of K562 cells. Key words Bcl-2 - Antisense peptide nucleic acid - Antisense oligonucleotide - K562 cells - Apoptosis CLC number Q255 Foundation item: This work was supported by the Key Foundation of Science & Technology Program of Guangzhou (No.2001-Z-037-01), and the Nature Science Key Foundation of Guangdong Province (No. 021195).Biography: LEI Xiao-yong(1970–), male, associate professor, doctor of medicine, Institute of Pharmacy and Pharmacology, Nanhua University, majors in tumor pharmacology.

Wortmannin Inhibits K562 Lukemic Cells by Regulating PI3k/Akt Channel In Vitro

The inhibitory effect ofwortmannin on leukemic cells and the possible mechanisms were examined. K562 cells were treated with wortmannin of various concentrations （3.125-100 nmol/L） for （0-72 h. MTT assay was used to evaluate the inhibitory effect of wortmannin on the growth of K562 cells. Cell apoptosis was detected by both Annexin-V FITC/PI double-labeled cytometry and transmission electron microscopy （TEM）. The expression of p-Akt, T-p-Akt, NF-kBp65 and IKK-κB was determined by Western blotting and reverse transcription-polymerase chain reaction （RT-PCR）. Our results showed that wortmannin obviously inhibited growth and induced apoptosis of K562 cells in vitro in a time- and dose-dependent manner. The IC50 value of wortmannin for 24 h was 25±0.14 nmol/L. Moreover, wortmannin induced K562 cells apoptosis in a dose-dependent manner. TEM revealed typical morphological changes of apoptosis in wortmannin-treated K562 cells, such as chromatin condensation, karyopyknosis, karyorhexis and apoptotic bodies. Additionally, several important intracellular protein kinases such as p-Akt, NF-κBp65 and IKK-κB experienced degradation of vari- ous degrees in a dose-dependent manner both at protein level and transcription level when cultured with wortmannin, but the expression of total Akt showed no change. It is concluded that wortmannin can inhibit the proliferation and induce apoptosis of K562 leukemia cells possibly by down-regulating the survival signaling pathways （PI3K/Akt and NF-κB channels）.

Effects of Root Extracts from <i>Panax ginseng</i>C. A. Meyer (Araliaceae) of Different Ages on K562 Cells

It is well accepted in China that elder ginsengs have more bioactivity and value than younger ones. However, there is little research about the comparison of beneficial effects of ginsengs with different ages. In this study, ginseng root extracts (GRE) were extracted from ginsengs of 5, 8, 12, 14, and 16 years old, respectively, using 55% ethanol and their effects on human leukemic K562 cells within 48 hours were tested by using Cell Counting Kit-8. The results show that there are significant increases in the cell viability of all the GRE groups compared with Control group within 32 hours. Furthermore, the growth curves of GRE groups were obviously distinct from each other. The cell viability of 5-year-old and 8-year-old GRE groups kept a rapid increase while that of 16-year-old GRE group showed a strong fluctuation within 28 hours. Our results demonstrate that root extracts from ginsengs of different ages contain different bioactivity constituents and have different effects on cell.

Study of Celastrol on Akt Signaling Pathway and Its Roles in the Apoptosis of K562 Cells

The purpose Celastrol, the main active compound of the Celastrus genus plants, belonging to Celastraceae, has recently marked antitumour potency on solid tumours of various derivations, Methods: We demonstrate here that Celastrol also present powerful antileukaemic potency through both growth arrest and apoptosis induction in K562 cells, which was accompanied by typical apoptotic morphological and sharp decreased expression of phosphorylation level of Caspase family members and Akt signaling pathway related proteins were determined by western blot before and after celastrol treatment, and further the effect of AKT signaling pathway on celastrol-induced-apoptosis was analyzed. However, in vitro treatment with Celastrol resulted in significantly reduced expression of phophorylation of Akt, Survivin and Bcl-2 significantly in K562 cells. Results: 25 nmol/L WORT (PI3K-Akt inhibitor) can significantly augmented cell apoptosis induced by Celastrol in K562 cells in dose-dependent manner, Moreover, most Caspase3,8,6 were activated in K562 cells during Celastrol treatment, 50 μmol/Lz-VAD-fmk (Caspase inhibitor) can to enhance the apoptosis induced by Celastrol. Discussion: These results suggest that the fact that Akt signaling pathway might act as new targets of Celastrol, correlates well with the sensitivity to Celastrol, as well as the rate of apoptosis induced by Celastrol, Mechanisms that regulate Akt signaling pathway may be provide novel opportunities for drug development.

硫化砷对K_(562)/ADM细胞HSP70蛋白表达的影响

目的 :探讨硫化砷 (As2 S2 )对K5 6 2 及其耐药细胞株K5 6 2 ADM细胞膜HSP70蛋白表达的影响。方法 :采用流式细胞仪 (FCM)测定K5 6 2 和耐药细胞K5 6 2 ADM细胞膜HSP70蛋白表达及细胞凋亡 ,利用RT PCR方法检测HSP70的mRNA水平。结果 :硫化砷能增加细胞膜HSP70蛋白表达 ,且与时间及浓度成正相关 ,而在mRNA水平上仍有较高的表达。K5 6 2 ADM细胞膜HSP70蛋白表达和细胞凋亡率均高于K5 6 2 细胞。结论 :硫化砷能增加细胞膜HSP70蛋白表达 。

K562/ADM耐药细胞株的建立及其生物学特性的初步观察

我们建立的K562/ADM耐药细胞株,在ADM浓度为2.4μg/m1(4.46μM)中已稳定培养3.5个月,传了30—35代,K562/ADM亦具有多药耐受件(Multidrug Resistance,MDR)的特点,对ADM、VCR、AT—1258和DDP的耐受性分别为K562的114.7、94.0、13.3和7.4倍,但对5—FU不产生交叉耐药。K562和K562/ADM的倍增时间分别为19.2h和52.8h,集落生成率分别为37.5％和11.1％,K562染色体数为34—68,中位数为56;K562/MDM染色体数为32—90,中位数为50,K562/ADM可做为耐药机理和克服耐药措施研究的极好模型。