Eha, a regulator of Edwardsiella tarda, required for resistance to oxidative stress in macrophages.

Edwardsiella tarda is distributed widely in a variety of hosts. Eha has recently been found to be its virulence regulator. In order to explore the mechanism of its regulation, we investigated the survival rates of wild type strain ET13, and its eha mutant and complemented strains in RAW264.7 macrophages under light microscopic observation as well as by counting bacterial CFUs on the plates. All of the different strains could live within the macrophages; however, the intracellular numbers of the wild type were significantly higher than the mutant when the incubation time extended 4 h or 6 h (P < 0.05). Furthermore, more ROS were produced by the mutant-infected cells, indicating that Eha may enhance ET13's capacity to detoxify ROS. In agreement with this, we found that the mutant exhibited more sensitivity by H2O2 disk inhibitory assay and less survival ability with H2O2 treatment. We further demonstrated that the bacterial antioxidant enzymes SodC and KatG were regulated by Eha with qRT-PCR and ß-galactosidase assay. Collectively, our data show Eha is required for E. tarda to resist the oxidative stress from the macrophages.

The role of regulator Eha in Edwardsiella tarda pathogenesis and virulence gene transcription.

Edwardsiella tarda is a pathogen with a broad host range that infects both animals and humans. Eha is a new transcriptional regulator identified in ET13, which is involved in the bacterial hemolytic activity. This study explored the effect of the Eha in the pathogenesis of E. tarda and the transcriptional regulation of the bacterial virulence genes (eseC, fliC, pagC and fimA). Our results found that the virulence of the eha mutant was 2.5-fold less than the one of its wild ET13 by LD50 in a murine model of i.p. infection, and the bacterial loads of the mutant displayed a different profile from the one of the wild strain. Most significantly, the mice infected with the mutant have greatly reduced acute inflammation in the liver, spleen and kidney compared to the ones infected with the wild. We further demonstrated that eseC, fliC and pagC were regulated directly by the Eha with qRT-PCR and ß-Galactosidase assay, but fimA wasn't done. The promoter regions of the genes modulated and the cly gene reported before had been found to contain a common conserved motif by using software. In addition, we found that the wild strain was more toxic to RAW264.7 macrophages, and induced less the host cell apoptotic responses than the eha mutant did. Altogether, these data suggested that the Eha was required for the bacterial infection and the transcriptive regulation of the important virulence genes of E. tarda.

Wogonin inhibits the proliferation of myelodysplastic syndrome cells through the induction of cell cycle arrest and apoptosis.

The present study aimed to assess the effects of the flavonoid, wogonin, and its underlying mechanism on myelodysplastic syndrome (MDS) in SKM-1 cells. In the present study, wogonin inhibited the cell proliferation of SKM­1 cells in a dose­ and time­dependent manner, with the concentration required to yield a half maximal inhibitory concentration (IC50) of 212.1 µmol/l at 24 h, and 43.4 µmol/l at 72 h. Furthermore, wogonin induced cell cycle arrest at the G0/G1 phase and induced the apoptosis of the SKM­1 cells, which possibly accounted for the antiproliferative effects of wogonin. Notably, the data in the present study revealed that wogonin upregulated the expression of p21Cip1 and p27Kip1, and downregulated the expression of cyclin D1 and cyclin­dependent kinase 4, causing a G0/G1 phase arrest, halting cell cycle progression, and inducing apoptosis in the MDS cells, which was mediated by the mitochondrial pathway through a modulation of the ratio of Bcl­2 to Bax. Therefore, the present study suggests that wogonin may be a logical therapeutic target in the treatment of MDS.

Eha, a transcriptional regulator of hemolytic activity of Edwardsiella tarda.

Hemolysis causes major symptoms such as the reddening skin and systemic hemorrhagic septicemia of diseased fish infected by Edwardsiella tarda. Cytolysin A (ClyA) is a pore-forming cytotoxic protein encoded by the clyA gene in Escherichia coli K-12. In this study, we observed that the heterologous expression of the eha gene from E. tarda could confer hemolytic activity upon a hemolytic-silent E. coli strain. The transcription of clyA is positively controlled by the eha gene in E. tarda by RT-PCR. We cloned and purified Eha protein which had shown preferential binding ability to the clyA sequences in its promoter region, as evidenced by gel shift assay. The eha controls the transcriptional start predominantly at 72 bp upstream in the clyA promoter region, as determined by primer extension assays. We suggest that Eha protein is a new positive regulator found in E. tarda. In addition, we constructed the eha mutant and complementary strains of E. tarda. The hemolytic activity of the eha mutant was found to be attenuated compared with the wild-type strain. The complementary strains restored the hemolytic activity to levels between those of the wild type and the eha mutation. Our results indicate that the Eha protein is an important positive regulator in the hemolytic properties of E. tarda.

[Reversal effect of gambogic acid on multidrug resistance of K562/A02 cell line].

This study was purposed to investigate the reversal effect of gambogic acid (GA) on multidrug resistance of K562/A02 cells and its mechanism. The IC(50) (half maximal inhibitory concentration) of adriamycin (ADM) was evaluated by MTT. Cell apoptosis was detected by flow cytometry. Morphological changes of K562/A02 cells were observed by fluorescent microscopy with DAPI staining. The expressions of Survivin and P-gp were determined by Western blot. The results showed that the IC(50) of ADM on K562 and K562/A02 cell proliferation were (1.42 ± 0.07) µg/ml and (28.42 ± 1.40) µg/ml respectively. GA ≤ 0.0625 µmol/L had no inhibitory effect on proliferation of K562 and K562/A02. 0.0625 µmol/L GA could enhance the sensitivity of K562/A02 cells to ADM (P < 0.05) and the reversal multiples was 1.53. The apoptotic rate was raised after treating with ADM combined with 0.0625 µmol/L GA for 48 h (P < 0.05). Morphological differences were typical and obvious between cells of control and treated groups under fluorescence microscopy using DAPI staining. After treating K562/A02 cells with ADM combined with 0.0625 µmol/L GA for 48 h, the expressions of Survivin and P-gp were down-regulated at protein levels. It is concluded that GA can enhance the sensitivity of K562/A02 cells to ADM, which may be related to increasing cell apoptosis and down-regulating expressions of Survivin and P-gp.

Effect of magnetic nanoparticles on apoptosis and cell cycle induced by wogonin in Raji cells.

Traditional Chinese medicine is gradually becoming a new source of anticancer drugs. One such example is wogonin, which is cytotoxic to various cancer cell lines in vitro. However, due to its low water solubility, wogonin is restricted to clinical administration. Recently, the application of drug-coated magnetic nanoparticles (MNPs) to increase water solubility of the drug and to enhance its chemotherapeutic efficiency has attracted much attention. In this study, wogonin was conjugated with the drug delivery system of MNPs by mechanical absorption polymerization to fabricate wogonin-loaded MNPs. It was demonstrated that MNPs could strengthen wogonin-induced cell inhibition, apoptosis, and cell cycle arrest in Raji cells by methylthiazol tetrazolium assay, flow cytometer assay, and nuclear 4',6-diamidino-2-phenylindole staining. Furthermore, the molecular mechanisms of these phenomena were explored by western blot, in which the protein levels of caspase 8 and caspase 3 were increased significantly while those of survivin and cyclin E were decreased significantly in wogonin-MNPs group. These findings suggest that the combination of wogonin and MNPs provides a promising strategy for lymphoma therapy.

Effect of magnetic Fe3O4 nanoparticles with 2-methoxyestradiol on the cell-cycle progression and apoptosis of myelodysplastic syndrome cells.

This study aims to evaluate the potential benefit of combination therapy of 2-methoxyestradiol (2ME) and magnetic nanoparticles of Fe(3)O(4) (MNPs-Fe(3)O(4)) on myelodysplastic syndrome (MDS) SKM-1 cells and its underlying mechanisms. The effect of the unique properties of tetraheptylammonium-capped MNPs-Fe(3)O(4) with 2ME on cytotoxicity was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell-cycle distribution and apoptosis were assessed by flow cytometry. The expression of cell-cycle marker protein was measured by Western blotting. Growth inhibition rate of SKM-1 cells treated with the 2ME-loaded MNPs-Fe(3)O(4) was enhanced when compared with 2ME alone. 2ME led to an increase of caspase-3 expression, followed by apoptosis, which was significantly increased when combined with an MNPs-Fe(3)O(4) carrier. Moreover, the copolymer of 2ME with MNPs- Fe(3)O(4) blocked a nearly two-fold increase in SKM-1 cells located in G(2)/M phase than in 2ME alone, which may be associated with an accompanying increase of p21 as well as a decrease in cyclin B1 and cdc2 expression, but there was no obvious difference between the MNPs-Fe(3)O(4) and control group. These findings suggest that the unique properties of MNPs-Fe(3)O(4) as a carrier for 2ME, a new anticancer agent currently in clinical trials, may be a logical strategy to enhance the therapeutic activity of MDS.

[Effect of sodium valproate on human myelodysplastic syndrome cell line SKM-1 and its mechanism].

This study was aimed to investigate the effect of sodium valproate(VPA) on human myelodysplastic syndrome cell line SKM-1 and its mechanism. The cell proliferation was determined by MTT assay, cell apoptosis was analyzed by flow cytometry. The expressions of c-flipl, c-flips and dlk1 mRNA were detected by RT-PCR. The results showed that VPA could inhibited the growth of SKM-1 cells in dose- and time-dependent manners. The flow cytometric analysis indicated that VPA could induce cell apoptosis, apoptosis rate increased in dose-dependent manner. The expressions of c-flipl, c-flips and dlk1 mRNA in SKM-1 cell treated with VPA decreased using of VPA. It is concluded that VPA can induce apoptosis and inhibited proliferation of SKM-1 cells. In this process, the decreasing of c-flipl, c-flips and dlk1 mRNA expression may play important roles.

[Gene expression in patients with myelodysplastic syndrome].

This study was aimed to investigate the expression of c-FLIPL, c-FLIPS and DLK1 mRNA in the patients with myelodysplastic syndrome (MDS) and its clinical significance. The mRNA expression of c-FLIPL, c-FLIPS and DLK1 in bone marrow mononuclear cells (BMMNC) of 16 patients with MDS and 3 controls were detected by RT-PCR. The results indicated that the expression of DLK1 mRNA was up-regulated in MDS, including RA and RAEB, as compared with controls (p < 0.05). There was no significant difference in expression of DLK1 between RA and RAEB patients (p > 0.05); the expression of c-FLIPL mRNA both in RA and RAEB patients was higher than that in controls (p < 0.05). There was no significant difference in expression of c-FLIPL between RA and RAEB patients (p > 0.05); the expression of c-FLIPS mRNA was not significantly different between MDS patients and controls (p > 0.05), but its expression in RAEB patients was significantly higher as compared with RA patients and controls (p < 0.05). It is concluded that the mRNA expressions of DLK1, c-FLIPL and c-FLIPS in MDS patients are abnormal, some of which may be useful as an important indicator for the evaluation of development in MDS.

Effects of magnetic nanoparticle of Fe3O4 on apoptosis induced by Gambogic acid in U937 leukemia cells.

This study was aimed to explore the potential therapy of Gambogic acid (GA) combined with magnetic nanoparticle of Fe3O4 (Fe3O4-MNP) on leukemia. The proliferation of U937 cells and the cytotoxicity were evaluated by MTT assay. Cell apoptosis was observed and analyzed by microscopy and flow cytometry respectively. The expressions of gene and protein were detected by quantitative real-time polymerase chain reaction and Western blot respectively. The results showed that GA enhanced the cytotoxicity for U937 cells in dose- and time-dependent manners. The Fe3O4-MNP itself had not cytotoxicity, but could enhance the inhibitory effect of GA on proliferation of U937 cells. The apoptotic rate of U937 cells induced by combination of GA with Fe3O4-MNP was higher than that by GA alone. The typical apoptotic features of cells treated with GA and Fe3O4-MNP were observed. The expression levels of caspase-3 and bax after co-treatment of GA and Fe3O4-MNP were higher than that exposed to GA or Fe3O4-MNP alone, but the expressions of bcl-2, NF-kappaB and survivin were down-regulated. It is concluded that Fe3O4-MNP can promote GA-induced apoptosis in U937 cells, and the combination of GA with Fe3O4-MNP may be a safer and less toxic new therapy for leukemia.

Synergistic effect of magnetic nanoparticles of Fe(3)O(4) 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.

[Regulation of 2-methoxyestradiol-induced cell apoptosis by mcl-1 and bax genes in myelodysplastic syndrome].

The purpose of this study was to explore the mechanism underlying the regulation of 2-methoxyestradiol (2-ME)-induced cell apoptosis by mcl-1 and bax gene in myelodysplastic syndrome (MDS). The MUTZ-1 cells were pretreated with 2-ME; then the activity of caspases-3 was determined by fluorescent colorimetry; the mRNA expressions of apoptosis-related genes (mcl-1) and bcl-2-related X protein (bax) were determined by RT-PCR. The results showed that as compared with control, the 2-ME enhanced the activity of caspase-3 in MUTZ-1 cells in a dose-and time-dependent manners (p<0.05); along with increasing of 2-ME concentration, the expression of intracellular mcl-1 mRNA reduced (p<0.05), meanwhile the expression level of mcl-1 mRNA negatively correlated to the activity of caspase-3 at the corresponding time points (r=-0.992, p<0.01), but the expression of bax mRNA did not show significant change (p>0.05). It is concluded that 2-ME can regulate the apoptosis of MDS cells through the pathway of down-regulating the expression of mcl-1 mRNA and activating the caspase-3.

[Experimental study of effect of As2S3 nanoparticles on human MDS cell line (MUTZ-1)].

OBJECTIVE: To in vitro study the inhibition effect and possible mechanism of As2S3 nanoparticles (As2S3 nano) on human MDS cell line MUTZ-1 and to compare with that of traditional As2S3. METHOD: MUTZ-1 cells were treated with As2S3 nano and traditional regular-sized particles (TRSP) at different concentrations. The cell growth inhibition rate was determined by MTT assay, cell apoptosis by morphology and flow cytometry (FCM), cell cycle by FCM and the activity of caspase-3 by chemiluminescence assay. RESULTS: Treatment of As2S3 nano and TRSP at concentrations of 2, 4, 8 and 16 micromol/L for 48 h could lead to a significant dose-dependent decrease of MUTZ-1 cells and induce apoptosis. The percentages of inhibition were 48.9%, 75.9%, 89.4% and 96.5% in As2S3 nano vs 14.5%, 25.4%, 34.7% and 51.5% in TRSP and apoptosis rates were (12.9 +/- 1.9)%, (19.2 +/- 2.2)%, (30.1 +/- 2.5)% and (45.9 +/- 2.3)% in As2S3 nano vs (5.3 +/- 1.8%)%, (11.1 +/- 2.6)%, (19.3 +/- 2.3)% and (25.5 +/- 2.5)% in TRSP respectively. There was statistically significant difference in these two groups (P < 0.01). The proportion of cell in G2/M phase and the activity of caspase-3 of MUTZ-1 cells treated with A2S32 nano were significantly higher than those treated with control group and As2S3 TRSP groups (P < 0.01). CONCLUSIONS: As2S3 nanoparticles and TRSP can inhibit the proliferation of MUTZ-1 cells and induce apoptosis, which maybe through activating caspase-3 pathways and increasing the proportion of G2/M phase. As2S3 nanoparticles can produce a much better antitumor effect than As2S3 TRSP do.

[Inhibition effect of gambogic acid on MUTZ-1 cell line and its possible mechanism].

This study was aimed to investigate the effects of gambogic acid on the cells of high-risk patients with myelodysplastic syndrome (MDS) in vitro and its mechanism. The inhibition effect of gambogic acid on growth of MUTZ-1 cell line of MDS-RAEB was detected by MTT method. Apoptosis and cell cycle were detected by morphological observation and flow cytometry respectively. The expressions of bax/bcl-2 gene at mRNA level were detected by RT-PCR. The results indicated that the Gambogic acid inhibited the growth of MUTZ-1 cells, the inhibitory rate of gambogic acid with the range of 0.2 - 0.8 microg/ml was enhanced along with increasing of drug concentration. Flow cytometric assay showed that the apoptotic rate of MUTZ-1 cells treated by gambogic acid also was enhanced along with increasing of drug concentration, the apoptotic rates resulting from gambogic acid (0, 0.4, 0.6, 0.8 microg/ml) were (5 +/- 0.5)%, (13 +/- 0.5)%, (37 +/- 0.7)% and (56 +/- 0.6)% respectively. The characteristic changes of apoptosis emerged in MUTZ-1 cells after being exposed to gambogic acid. Gambogic acid could significantly down-regulate the expressions of bcl-2 gene in a dose dependent manner, however, it had no effects on bax gene. It is concluded that within the range of concentration from 0.4 to 0. 8 microg/ml, gambogic acid can inhibit the growth of MUTZ-1 cells by inducing their apoptosis and down-regulating the expression of bcl-2 gene, which may be one of the main mechanisms underlying its antitumor effects.

Local effects of retrovirally transduced endostatin-expressing human umbilical cord blood CD34+ cells on transplanted malignancy in a mouse model of hepatic cancer.

Antiangiogenesis has been exploited as an effective approach to inhibit the growth of solid tumors. This technique has been evaluated using various vectors in several xenograft animal models to demonstrate the efficacy of endostatin gene therapy against cancer growth. However, previous studies have not examined the use of cord blood CD34+ cells as endostatin-producing cells for gene therapy against hepatoma. This exploratory study was done to investigate the local effects of CD34+ cells transduced with the endostatin gene on a mouse xenograft tumor model. The human endostatin gene was transferred into CD34+ cells using the recombinant retrovirus plasmid, pLncx/endo. Expression was verified by RT-PCR and Western blot analyses, confirming the stable expression and secretion of endostatin from the transferred CD34+ cells. The proliferation of vascular endothelial cells was evaluated by MTT assay and found to decrease by about 59.9% when treated with the supernatant of cultured transfected CD34+ cells in vitro. These genetically modified cord blood CD34+ cells were implanted intratumorally and tumor regression was evaluated after 2 weeks. The average size of a xenograft tumor in the CD34+/endo group was reduced 31.39% compared to that in the untreated mice or those transplanted with CD34+ cells transduced with a control vector. The microvascular density of the tumor decreased 62.45% in the treated group. The expression of proliferation cell nuclear antigen (PCNA) also decreased significantly in the treated group. Moreover, the apoptotic index (AI) of tumors, as evaluated by TUNEL staining, was significantly enhanced in the treatment group. Our findings indicate that angiogenesis of the xenograft tumor in mice may be inhibited by local administration of genetically modified CD34+ cells expressing the endostatin gene. This novel approach may lead to a new direction of cell-based gene therapy for malignancy.

[Enhancement of reversing drug resistance of K562/A02 cells to adriamycin by ultrasound-induced cavitation].

This study was aimed to investigate the effects of low frequency and power ultrasound combined with adriamycin on apoptosis of drug-resistant leukemia cell line K562/A02 in vitro, to find out the parameters of optimal exposure, and to explore the possible mechanism reversing drug-resistance of K562/A02 cells. The K562/A02 cells in logarithmic growth phase were used in experiments. The experiments were divided into 4 groups: group control, group adriamycin (A02) alone, group ultrasound (US) alone and group A02+US. The trypan blue dye exclusion test and MTT assay were used to determine the cell viability; Wright's staining was used to detect the apoptosis; the flow cytometry was used to analyze the drug concentration, and the scanning electron microscopy was used to observe the changes of cell surface. The results showed that the significant differences in cell viability, intracellular adriamycin concentration and changes of cell membrane were found between ultrasound-treated and untreated cells in the presence of various concentration of adriamycin. The exposure to ultrasound at 20 kHZ, 0.25 W/cm2 for 60 seconds could obviously decrease LC50 of adriamycin to K562/A02 cells, while the exposure to ultrasound at 20 kHZ, 0.05 W/cm2 for 60 seconds could kill K562/A02 cells at once. After being treated by low frequency ultrasound, the small holes with diameter about 1-2 microm in the cell surface appeared. The ultrasound increased the adriamycin concentration in the cells, accelerated the formation of apoptotic bodies, and promoted apoptosis of adriamycin-resistant cells. It is concluded that the ultrasound at optimal parameters enhances inhibitory effect of adriamycin on drug-resistant cell line, thereby reverses drug-resistance of drug-resistant cell line through sound-hole effect in tumor cells resulting from ultrasound induced cavitation.

[Antitumor effects of low-frequency ultrasound combined with adriamycin on human leukemia multidrug resistance cell line K562/A02].

BACKGROUND & OBJECTIVE: Researches have shown that ultrasound can enhance the sensitivity of tumor cells towards chemotherapy drugs, thus to inhibit cell proliferation. This study was to investigate the antitumor effect of low-frequency ultrasound combined with adriamycin on human leukemia multidrug resistance (MDR) cell line K562/A02. METHODS: K562/A02 cells were divided into four groups: blank control group, adriamycin group, ultrasound group, and adriamycin plus ultrasound group. The trypan blue dye exclusion assay and MTT assay were used to determine the viability and proliferation of K562/A02 cells, while Wright's stain and flow cytometry were used to determine the apoptosis and the concentration of adriamycin. The expression of P-glycoproteins (P-gp) was detected using immunocytochemistry. RESULTS: Ultrasound (20 kHz, 0.25 W/cm2, 60s) combined with adriamycin (7.5 microg/mL) induced more apoptosis of K562/A02 cells than adriamycin alone. Compared with the adriamycin group, ultrasound at a frequency of 20 kHz and an intensity of 0.5 W/cm2 exerted an acute killing effect on cells. Ultrasound increased the intracellular concentration of adriamycin and promoted apoptosis of K562/A02 cells, but did not change the expression of P-gp on the cell membrane. CONCLUSION: Ultrasound at a frequency of 20 kHz, an intensity of 0.25 W/cm2 and duration of 60s can enhance the killing effect of adriamycin on K562/A02 cells.

[Sodium valproate synergizes adriamycin to inhibit proliferation and induce apoptosis in myelodysplastic syndrome cell line].

The aim of this study was to investigate the tumor suppression efficacy of a histone deacetylase inhibitor, sodium valproate combined with adriamycin in the treatment of myelodysplastic syndrome cell line MUTZ-1. After treated with different concentrations of sodium valproate alone, adriamycin alone or combination of them, growth curve of MUTZ-1 cell line were detected; growth of the tumor cells were analyzed by flow cytometry and morphology method. The results indicated that when the myelodysplastic syndrome cell line MUTZ-1 was treated with adriamycin (0.039 microg/ml, 0.078 microg/ml, 0.156 microg/ml, 0.312 microg/ml, 0.4 microg/ml), the tumor growth inhibition rates were 5.08 +/- 0.79%, 12.32 +/- 2.39%, 23.65 +/- 1.34%, 43.33 +/- 2.38% and 47.85 +/- 1.46% (p < 0.05), 0.25 mmol/L sodium valproate did not show apoptosis effect, but could synergize adriamycin to promote apoptosis. When the myelodysplastic syndrome cell line MUTZ-1 treated with two drug combination, the tumor growth inhibition rates were 23.46 +/- 1.12%, 49.87 +/- 0.84%, 52.37 +/- 1.05%, 78.43 +/- 4.34% and 82.47 +/- 1.04% (p < 0.05), and displayed concentration-dependent manner. All the data above were significantly different from those in control (p < 0.05). Sodium valproate showed obvious effect at concentration of 0.078 microg/ml adriamycin. After treated with 0.25 mmol/L sodium valproate and 0.078 microg/ml adriamycin for 72 hours, MUTZ-1 cell line showed typical apoptosis morphological character. It is concluded that sodium valproate may enhance the efficacy of adriamycin on MUTZ-1 cell line.

[Effects of sodium valproate on proliferation and apoptosis of human myelodysplastic syndromes cell line MUTZ-1].

BACKGROUND & OBJECTIVE: Myelodysplastic syndromes (MDS) are heterogeneous disorders with the expansion of malignant clones. No satisfactory treatment for MDS is available. Sodium valproate (VPA) can inhibit the proliferation of tumor cells by inducing G(0)/G(1) phase arrest and cell apoptosis. This study was to investigate the effects of VPA on the proliferation of MDS cell line MUTZ-1, and explore possible mechanisms. METHODS: MUTZ-1 cells were treated with VPA. Cell proliferation was determined by MTT assay. Cell morphology was observed under microscope and transmission electron microscope. Cell apoptosis and cell cycle were analyzed by flow cytometry (FCM). The expression of p21(WAF1) (cyclin-dependent kinase inhibitor) was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. RESULTS: VPA inhibited the proliferation of MUTZ-1 cells in concentration-and time-dependent manners. When treated with 4 mmol/L VPA for 72 h, typical apoptotic morphologic features appeared in MUTZ-1 cells: condensation of cells and nuclear chromatin, disintegration of nuclear chromatin, and apoptotic bodies were observed under microscope; aggregation and margination of apoptotic nuclear chromatin, cytoplasm condensation, and irregular chromatin masses were observed under transmission electron microscope. The apoptosis rate was significantly higher in the cells treated with 1, 2, and 4 mmol/L VPA for 72 h than in untreated cells [(3.14+/-0.87)%, (14.90+/-1.04)% and (22.46+/-1.74)% vs. (0.99+/-0.35)%, P<0.05]. After treatment of VPA, cell cycle was arrested obviously at G0/G1 phase (P<0.05)û the mRNA and protein levels of p21(WAF1) were up-regulated in MUTZ-1 cells (P<0.05). CONCLUSIONS: VPA could induce G(0)/G(1) phase arrest, inhibit the proliferation and induce the apoptosis of MUTZ-1 cells in vitro. The mechanism may be associated with the up-regulation of p21(WAF1).

[Apoptosis of human myelodysplastic syndrome cell Line MUTZ-1 induced by sodium valproate].

To study the effects of sodium valproate (VPA) on human myelodysplastic syndrome cell line MUTZ-1. The cell proliferation was determined by MTT assay, apoptotic morphological features were observed by light microscopy and transmission electronmicroscopy, cell apoptosis and cell cycle shift were analyzed by flow cytometry (FCM). The results showed that VPA could inhibit the growth of MUTZ-1 cells in dose-and time-dependent manners. The typical apoptotic morphological features appeared in MUTZ-1 cells treated with 4 mmol/L VPA for 72 hours. Pyknosis of cells and nuclei, disintegration of nuclear chromatin and apoptotic body could be observed by light microscopy. Aggregation and margination of nuclear chromatin, concentration of plasm, increment of density and chromatin mass of irregular size could be observed by transmission electronmicroscope. The flow cytometric analysis indicated that the VPA could induce cell apoptosis, apoptosis rate increased in dose-dependent manner, ratio of cells at G(0)/G(1) phase increased and ratio of cells at S phase decreased in dose-dependent manner, the cells were arrested at G(0)/G(1) phase. It is concluded that the VPA can induce apotosis and inhibite proliferation of MUTZ-1 cells via arresting cells at G(0)/G(1) phase.