PubMed Health⌕ Search

Biomedical subjects

Yong You

Publications and source records attributed to Yong You.

At least 19 recordsLinked to original sources
PubMed2006

[Proliferation inhibiting and apoptosis inducing effects of parthenolide on human multiple myeloma cells].

OBJECTIVE: To investigate the effect of parthenolide (PTL) on human multiple myeloma (MM) cells in vitro and its mechanism. METHODS: Human MM cells of the line PRMI8266 were cultured and treated with PTL of the concentrations of 1, 2.5, 5, 7.5, and 10 micromol/L for 24, 48, or 72 hours. MM cells treated with DMSO were used as control group. The optical density was measured so as to draw a growth curve. The cell viability was detected by MTT and trypan-blue exclusion. The apoptosis was detected by flow cytometry. AO/EB staining and Wright-Giemsa staining were used to observe the morphological changes of the cells by fluorescence microscope and light microscope respectively. The caspase-3 activity was evaluated by BD ApoAlert Caspase Colorimetric Assay Kit. RESULTS: PTL significantly inhibited the proliferation and viability of the MM cells time and dose-dependently (all P < 0.01), and significantly induced the cell apoptosis after 48 h in a dose-dependent manner (P < 0.01). The early cell apoptosis rates for PTL of the concentrations of 2, 5 and 10 micromol/L were 17.1% +/- 2.6%, 33.6% +/- 3.8%, and 40.9% +/- 3.1% respectively, all significantly higher than that of the control group (5.6% +/- 1.2%, all P < 0.01). The MM cells treated with PTL of the concentration of 5 micromol/L for 48 h showed typical cell apoptotic features. The caspase-3 activity of the MM cells was enhanced significantly by PTL in a time and dose-dependent manner (all P < 0.01). CONCLUSION: This first report of anti-proliferation and apoptosis induction effects of PTL on MM cells shows that able to significantly inhibit the proliferation and induce the apoptosis of MM cells and enhance the caspase-3 activity, PTL may be a potentially useful drug for treatment of MM.

Actihaemyl↗
PubMed2006

Design of LNA probes that improve mismatch discrimination.

Locked nucleic acids (LNA) show remarkable affinity and specificity against native DNA targets. Effects of LNA modifications on mismatch discrimination were studied as a function of sequence context and identity of the mismatch using ultraviolet (UV) melting experiments. A triplet of LNA residues centered on the mismatch was generally found to have the largest discriminatory power. An exception was observed for G-T mismatches, where discrimination decreased when the guanine nucleotide at the mismatch site or even the flanking nucleotides were modified. Fluorescence experiments using 2-aminopurine suggest that LNA modifications enhance base stacking of perfectly matched base pairs and decrease stabilizing stacking interactions of mismatched base pairs. LNAs do not change the amount of counterions (Na+) that are released when duplexes denature. New guidelines are suggested for design of LNA probes, which significantly improve mismatch discrimination in comparison with unmodified DNA probes.

2-Aminopurine↗
PubMed2006

Assessment of bone marrow mesenchymal stem cell biological characteristics and support hemotopoiesis function in patients with chronic myeloid leukemia.

Mesenchymal stem cells (MSCs) are of great therapeutic potential because of their ability to self-renew and differentiate into multiple tissues. Compare to allogenetic MSCs, autologous MSCs from patients needed cell-based therapy may be an ideal alternative stem cell source. However, characteristics of MSCs from a disease state are poorly understood. So, we have isolated and characterized MSCs from choronic myeloid leukemia (CML) patients and compared them with MSCs derived from normal adult bone marrow. Our results showed that CML derived MSCs are similar to normal MSCs in phenotype, morphology and multi-differentiation capacity. Moreover, CML derived MSCs did not express BCR/ABL gene and Ph chromosome, and had not the ability to development tumor in nude mice. At last, they could express hematopoietic cytokines, and possessed hematopoietic supportive ability. These findings indicate that MSCs derived from CML patients' bone marrow may be an attractive tool for clinical needs.

Adult↗
PubMed2006

Allogeneic peripheral blood hematopoietic stem cell transplantation for patients with hematologic malignancies.

To investigate the therapeutic effects and associated complications of allogeneic peripheral blood stem cell transplantation (allo-PBSCT). 40 patients with various malignant hematopoietic diseases received allo-PBSCT. The preparative regimens were based on BUCY2 or modified BUCY2. The acute graft-versus host disease (aGVHD) was prevented by cyclosporin A and short-term MTX regimen in all patients. Two patients from donors with one fully mismatched HLA on DRB1 locus and 4 from unrelated donor also administered Zenapox (CD25 MAb) at dosage of 1 mg/kg every day on the day before transplantation and day 4 after transplantation. These 6 patients were also treated with mycophenolate mofetil (MMF). Transfusion of the donor cells: The median of the transfused nucleated cells was 5.38 x 10(8)/kg and that of the CD34+ cells was 7.8 x 10(6)/kg respectively. All the patients gained hematopoietic reconstruction except one who died of infection before engraftment. Seven patients got II degrees-IV degrees aGVHI) and the incidence was 17.5%. Fourteen patients got cGVHD and the incidence was 53.8% in the patients who survived over 6 months. Twenty-eight patients had fever or other characteristics of infection. The median follow-up time was 13.8 months. The incidence of transplantation related mortality (TRM) was 17.5% and 2 patients relapsed (5.0%). It was concluded that allo-PBSCT can reconstruct hematopoiesis quickly and is a favorable therapeutic method for leukemia.

Adolescent↗
PubMed2006

[A reverse transcriptase-polymerase chain reaction method improving the specific amplification of caveolin-1 gene sequences].

OBJECTIVE: To construct a reverse transcriptase-polymerase chain reaction (RT-PCR)approach that can improve the specificity of primers while dropping down the nonspecific amplification. METHODS: In the recent study we reported a new RT-PCR assay which improved markedly the specificity. However its efficiency of regressing nonspecific amplification remains to be accurately checked and further documented. In primer design, we looked over again some sequences that showed differences at 5' or 3' ends between human CAV1 and mouse Cav1 genes. cDNAs and the diluted plasmids which harbored the sequence of human CAV1 or mouse Cav1 gene were chosen as the templates. The ordinary PCR compared with one, of which primers modified by phosphorothioate and combined with proofreading polymerase, for their efficiencies of nonspecific amplification inhibited. RESULTS: Taq DNA polymerase without proofreading activity could efficiently catalyze the extension of primers with a single or multiple mismatched base pairs at the 3' terminus, but the kind of primer extension can be effectively blocked by phosphorothioate modified primers combined with proofreading polymerase. Compared with ordinary PCR reaction, this new PCR method can effectively regress the primer mismatched amplification of 50 ng DNA almost equaling to 2 x 10(4) unmatched template copies in a final volume of 50 microL. CONCLUSION: Compared with the first generation of polymerases with or without proofreading activities mediating RT-PCR reaction, the introduction of nuclease-resistant 3' modified primers (3' phosphorothioate primer extension) can offer more simplicity, accuracy, and also decrease cost.

Animals↗
PubMed2006

[Thapsigargin-induced apoptosis of K562 cells and its mechanism].

The aim was to study the apoptotic induction effect of thapsigargin on leukemia cell line K562 and its possible mechanism. After the treatment of leukemia cell line K562 by thapsigargin, morphological change of apoptotic cells was investigated by AO/EB fluorescent staining under fluorescent microscope; apoptosis rate was determined with annexin V-FITC/PI double staining by flow cytometry; intracellular calcium concentrations ([Ca(2+)]i) were measured by fluorescence spectrophotometer with calcium sensitive fluorescence indicator Fura-2/AM; mitochondrial transmembrance potentials (Delta Psi m) was detected on flow cytometry through staining of Rhodamine (Rh123); the changes of caspase-3, -7, -9, -12, cytochrome C, GRP78 proteins were detected by Western blot. The results showed that K562 cells cultured in 4 micromol/L thapsigargin for 48 hours exhibited typical morphological changes of apoptotic cells under fluorescent microscope, including shrinkage of cell, condensation of chromatin, breakage of nuclear, formation of apoptotic bodies, fluorescence of yellow green and pellet observed in early apoptoyic cells and hyacinth fluorescence of chromatin showed in late apoptotic cells. 24 and 48 hours after exposure to 1, 2, 4, 8 micromol/L thapsigargin, the apoptotic rates of K562 were respectively 7.51%, 11.65%, 23.22%, 30.56% and 12.85%, 20.27%, 31.51%, 44.16%, in dose-dependent manner, and were statistically significant when compared with the controls (P < 0.05). The apoptotic rate of K562 was dose- and time-dependent in experiment range. The enhancement of [Ca(2+)]i and the decrease of the Delta Psi m in K562 cells were induced by thapsigargin and were dose-dependent in experiment range, compared with control, P < 0.05. Western blot results indicated that cleavage and activation of caspase-3, -7, -9, -12, releasing of cytochrome C from mitochondria, upregulation of GRP78 expression at the endoplasmic reticulum were induced in K562 cells after 24 hours exposure of 4 micromol/L thapsigargin. It is concluded that thapsigargin induces endoplasmic reticulum stress-induced apoptosis in K562 cells. Endoplasmic reticulum is a novel important initiatory site of apoptosis in cells; the cleavage and activation of caspase-3, -7, -9, -12 play very important role in endoplasmic reticulum stress-induced apoptosis of K562 cells and is one of the important mechanisms for thapsigargin-induced apoptosis. Thapsigargin-induced apoptosis in K562 cells is associated closely with the disruption of the Delta Psi m and the release of cytochrome C from mitochondria, mitochondria participates in endoplasmic reticulum stress-induced apoptosis in K562 cells.

Apoptosis↗
PubMed2006

[Biological characteristics and ability of supporting hematopoiesis of bone marrow mesenchymal stem cells pre- and post-cryop-reservation].

This study was aimed to observe the biological characteristics of cryopreserved bone marrow mesenchymal stem cell (MSC) and to examine their abilities to support in vitro hematopoiesis. Bone marrow MSC were cryopreserved in -196 degrees C liquid nitrogen for 4 weeks (short term) and 9-15 months (medium term) with IMDM containing 10% DMSO, 40% fetal calf serum as cryoprotectant. The viability, proliferation, immunophenotype, in vitro differentiation and ability of supporting hematopoiesis of thawed MSC were investigated and compared with these of pre-cryopreserved MSC. The results showed that the cell viability were (93 +/- 2.51)% and (90 +/- 3.75)% for MSC cryopreserved as long as 4 weeks or 9-15 months respectively. However, there were no changes detected, as compared with pre-cryopreserved MSC in immunophenotype, abilities of proliferation and supporting colony forming of CFU-GM, CFU-E and CFU-GEMM. It is concluded that bone marrow-derived MSC can be stored in liquid nitrogen for short-term (4 weeks) or medium-term (9-15 months) without changes of abilities of proliferation, differentiation and hematopoiesis support.

Blood Preservation↗
PubMed2006

[VCAM-1 and E-selectin expression in extravillous cytotrophoblasts of severe preeclampsia].

OBJECTIVE: To investigate the expression pattern of vascular cell adhesion molecule-1(VCAM-1) and endothelial selectin (E-selectin) in the placental bed extravillous cytotrophoblast (EVCT) as well as its relationship with preeclampsia. METHODS: Placentas from severe preeclampsia (n=20) and gestional age-matched normal pregnancies (n=20) were studied. The staining intensity and the Mean Optical Density (MOD) of VCAM-1 and E-selectin in EVCT of placental bed deciduas were measured by immunohistochemistry. RESULTS: The staining intensity and MOD of VCAM-1 and E-selectin on placental bed EVCT in severe preeclampsia were significantly lower than those in the control group respectively (P<0.05, P<0.01). CONCLUSION: The decreased EVCT expression of vascular adhesion phenotype VCAM-1 and E-selectin may account for the shallow trophoblast invasion in preeclampsia, which is the major pathological change of this disease.

Adult↗
PubMed2006

[Mechanism of G2/M blockage triggered by activated-Chk1 in regulation of drug-resistance in K562/A02 cell line].

The study was purposed to investigate the effect of phosphorylated-chk1 on cell cycle and apoptosis of human erythroleukemic cell line K562 and K562/A02, and to explore the mechanism of chk1 in regulation of drug-resistance of leukemia cells. After treatment with adrimycin for six hours, the cell cycle distribution was detected by flow cytometry; the Chk1mRNA expression was detected by RT-PCR and the Chk1 phosphorylation level was detected by Western blot. Under the condition of down-regulation of Chk1mRNA expression in cells transfected with Chk1 short hairpin RNA, the cell apoptosis rates were detected by flow-cytometry following adrimycin. The results indicated that the proportion of K562/A02 cell line in G2/M phase was (54.12 +/- 0.57)% at 6 hours after drug treatment, significantly higher than that of K562 cell line (36.99 +/- 1.28)%. No evident difference of the Chk1mRNA expression was observed between K562 and K562/A02 cell lines, while elevated Chk1 phosphorylation following DNA damage induced by adriamycin was observed in the K562/A02 cell line (0.79 +/- 0.56), significantly higher than that in K562 cell line (0.27 +/- 1.47). The cell apoptosis rate of the Chk1 shRNA group in K562/A02 cell line was 3.84-fold of blank vector group, but that in K562 cell line was 1.30-fold of blank vector group. It is concluded that the increased chk1 activity that delay the progress of cell cycle are associated with cellular resistance to adrimycin in the K562/A02 cell line.

Apoptosis↗
PubMed2005

Effects of adenovirus mediated vascular endothelial growth factor gene transfer on reconstitution of hematopoiesis in post-bone marrow transplantation mice.

BACKGROUND: Bone marrow transplantation (BMT) conditioning procedure is considered as the cause of damage to bone marrow microvasculature and the delay of hematopoiesis recovery. However, hematopoiesis regulation post BMT by vascular endothelial growth factor (VEGF) has not yet been studied. In this study, adenovirus were used to investigate the effects of VEGF gene transfer on preventing damages to bone marrow microenvironment and its promotion of hematopoiesis in post-BMT mice. METHODS: Recombinant adenovirus (Ad)-enhanced green fluorescent protein (EGFP)/hVEGF165 was injected via tail vein into BALB/c mice undergoing syngeneic BMT. During the different phases post BMT, the distribution of adenovirus and the plasma levels of hVEGF were measured as well as the numbers of white blood cells (WBC), platelet (PLT) and red blood cells (RBC) in peripheral blood. At the same time, the mice were injected with Chinese ink via tail vein, following which the tibias were separated and were used for analysis of bone marrow microvasculature surface area and cellularity. RESULTS: Significant expression of EGFP and hVEGF was observed in multiple organs at different phases post BMT, and the plasma level of hVEGF was up to (866.67 +/- 97.13) pg/ml. The recovery of WBC, PLT and RBC of the group treated with recombinant adenovirus Ad-EGFP/hVEGF165 were significantly more rapid than those of other BMT groups (P < 0.05, respectively). At the 20th day post BMT, the percentage of bone marrow microvasculature surface area in group treated with VEGF [(61.2 +/- 4.0)%] returned to normal level [(62.0 +/- 5.0)%, P > 0.05]. The restoration of hematopoiesis was retarded more than that of microvasculature. The cellularity of bone marrow in each group was still lower than that of normal control [(62.3 +/- 4.0)%, P < 0.05] at the 30th day post BMT, but the percentage in group treated with VEGF at the 20th and 30th days post BMT [(46.5 +/- 5.0)% and (55.1 +/- 4.5)%] exceeded those of other BMT groups (P < 0.05, respectively). CONCLUSION: VEGF gene transfer mediated by adenovirus may protect the hematopoietic microenvironment to promote the restoration of hematopoiesis in post-BMT mice.

Adenoviridae↗
PubMed2005

Effects of fluorescent dyes, quenchers, and dangling ends on DNA duplex stability.

Single and dual-labeled fluorescent oligodeoxynucleotides are used in many molecular biology applications. We investigated the effects of commonly used fluorescent dyes and quenchers on the thermodynamic stability of a model probe-target DNA duplex. We demonstrate that those effects can be significant. Fluorescent dyes and quenchers were attached to the probe ends. In certain combinations, these groups stabilized the duplex up to 1.8kcal/mol and increased T(m) up to 4.3 degrees C. None of the groups tested significantly destabilized the duplex. Rank order of potency was, starting with the most stabilizing group: Iowa Black RQ approximately Black Hole 2>Cy5 approximately Cy3>Black Hole 1>QSY7 approximately Iowa Black FQ>Texas Red approximately TAMRA>FAM approximately HEX approximately Dabcyl>TET. Longer linkers decreased stabilizing effects. Hybridizations to targets with various dangling ends were also studied and were found to have only minor effects on thermodynamic stability. Depending on the dye/quencher combination employed, it can be important to include thermodynamic contributions from fluorophore and quencher when designing oligonucleotide probe assays.

Base Sequence↗
PubMed2005

[Protein kinase C inhibitor Gö6976 sensitizes arsenic trioxide-induced cell apoptosis in chronic myeloid leukemic cells].

To investigate the As(2)O(3)-chemosensitization of Gö6976 in K562 cells by its abrogation of As(2)O(3)-induced G(2)/M cell cycle arrest, K562 cells were treated with As(2)O(3) (5 micromol/L) and Gö6976 with various concentrations, the distributions of cell cycles were detected by flow cytometry, the cell viability was observed by trypan blue exclusion test and cell proliferation was tested by MTT assay. The results indicated that having treated by As(2)O(3) for 24 h and 48 h, the proportion of K562 cells in G(2)/M phase were (38.02 +/- 7.70)% and (32.58 +/- 7.43)% respectively, and no obvious cell apoptosis appeared. 50 nmol/L Gö6976 combined with As(2)O(3) decrease the proportion of cells in G(2)/M phase to (23.24 +/- 2.93)% and (16.18 +/- 1.60)% respectively and increase the proportion of cells in subG(1) phase to (11.82 +/- 2.31)% and (27.80 +/- 2.89)% respectively. Gö6976 abrogated G(2)/M cell cycle arrest induced by As(2)O(3) and increased cell apoptosis in a concentration- and time-dependent manner. Additionally, comparing to the control group, Gö6976 combined with As(2)O(3) decreased the cell viability and depressed the cell proliferation, but Gö6976 alone showed no same effect on them. In conclusion, the effects of AS(2)O(3)-chemosensitization of Gö6976 on K562 cells is associated with its abrogation of As(2)O(3)-induced G(2)/M cell cycle arrest.

Antineoplastic Agents↗
PubMed2005

Inhibitory effect of anti-fas ribozyme on apoptosis of mouse T cells.

BACKGROUND & OBJECTIVE: Tumor cells can express FasL, and induce apoptosis of activated T cells expressing Fas, which is so called "Fas counterattack". This study was to investigate inhibitory effect of anti-Fas ribozyme on apoptosis of mouse T cells, and explore a new way to enhance antitumor ability of T cells. METHODS: A hammerhead ribozyme targeting Fas mRNA was synthesized, its in vitro cleavage reaction was performed. Anti-Fas ribozyme was transfected into mouse spleen T cells by electroperation (ribozyme-transfected group), empty control and mock-transfected groups were set up. Fas expression on T cells was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. After treatment of anti-Fas antibody (JO(2)), cell apoptosis was measured by flow cytometry, proliferation of T cells was measured by MTT assay. In vitro killing activity of cytotoxic T lymphocytes (CTLs) was detected by lactate dehydrogenase (LDH) releasing assay. RESULTS: Anti-Fas ribozyme cleaved Fas mRNA efficiently with a rate of 60%. mRNA level of Fas was significantly lower on ribozyme-transfected cells than on control and mock-transfected cells (0.4 vs. 1.1, and 1.0, P < 0.01)u its protein level was according to this result. After treatment of JO(2), cell apoptosis rate was significantly lower in ribozyme-transfected group than in the rest 2 groups (35% vs. 86%, and 87%, P < 0.01), but cell proliferation rate was significantly higher in ribozyme-transfected group than in the rest 2 groups (208% vs. 100%, and 98%, P < 0.01). In vitro killing activity of CTLs was significantly stronger in ribozyme-transfected group than in the rest 2 groups (67% vs. 32%, and 31%, P < 0.01). CONCLUSION: Anti-Fas ribozyme can remarkably suppress Fas expression on mouse activated spleen T cells, and protect T cells from Fas-mediated apoptosis, which may enhance antitumor ability of T cells.

Animals↗
PubMed2005

[Recombinant adenovirus mediated hVEGF165 gene transfer promotes recovery of hematopoiesis in post-BMT mice].

To investigate the effects of vascular endothelial growth factor (VEGF) on the recovery of hematopoiesis in post-BMT mice, the recombinant adenovirus Ad-EGFP/hVEGF(165) was injected into syngeneic BMT BALB/c mice via the tail vein. At day 10, 20, 30 after BMT, the in vivo expression of hVEGF(165) was measured. At the same different time points, the numbers of WBC, Plt, RBC in peripheral blood and MNC in bone marrow were counted. By the way, the bone marrow MNCs at day 30 post-BMT were used for further CFU-S assay. The results indicated that a long-term expression of hVEGF(165) in plasma and different organs was successfully mediated by recombinant adenovirus. At each time point of post-BMT, the numbers of WBC, Plt, RBC as well as bone marrow MNC observed in the group treated with recombinant adenovirus Ad-EGFP/hVEGF(165) were lower than those of the normal control group, but were higher than those in other testing groups (P < 0.05). The number of CFU-S (21.4 +/- 2.67) formed by bone marrow MNC at day 30 after BMT reached to the normal level (19.50 +/- 2.46) (P > 0.05), which was much higher than that in other groups (P < 0.05). It is concluded that hVEGF(165) gene transfer mediated by recombinant adenovirus plays a role of promoting the recovery of hematopoiesis in post-BMT mice.

Adenoviridae↗
PubMed2005

[Expression and significance of melanoma antigen gene-3 in endoplasmic reticulum stress-induced apoptosis of K562 cells].

This study was aimed to explore the expression and significance of melanoma antigen gene-3 (MAGE-3) in endoplasmic reticulum stress-induced apoptosis. After the treatment of leukemia cell line K562 and its multidrug-resistant cell line K562/A02 by thapsigargin, intracellular calcium concentrations ([Ca(2+)]i) in K562 and K562/A02 were measured by fluorescence spectrophotometer with calcium sensitive fluorescence indicator Fura-2/AM; expression changes of glucose-regulated protein 78 (GRP78) were detected by Western blot; morphological change of apoptotic cell was investigated by AO/EB fluorescent staining under fluorescent microscope; apoptosis rate was determined by terminal deoxyribonucleotidyl transferase (TdT)-mediated dUTP nick end labelling (TUNEL) staining; the expression of MAGE-3 gene mRNA was detected by RT-PCR. The results showed that (1) thapsigargin induced the enhancement of [Ca(2+)]i with different extent in K562 and K562/A02 cells, and the enhancement of [Ca(2+)]i was dose-dependent in experiment range. At the same time, thapsigargin induced upregulation of GRP78 protein expression and typical apoptotic changes of K562 and K562/A02 cells, apoptotic rate was also dose-dependent in experiment range. The [Ca(2+)]i in K562/A02 cells were higher than that in K562 cells. (2) in the course of endoplasmic reticulum stress-induced apoptosis by thapsigargin, the expression of MAGE-3 gene mRNA was remarkably downregulated. Moreover, the expression of MAGE-3 gene mRNA in K562/A02 cells was higher than that in K562 cells. It is concluded that (1) thapsigargin induces endoplasmic reticulum stress-induced apoptosis of K562 and K562/A02 cells in experiment range, and this may be associated with downregulation of MAGE-3 mRNA expression or MAGE-3 gene may participates in the regulation of endoplasmic reticulum stress-induced apoptosis. (2) MAGE-3 gene may possess anti-apoptotic activity, multidrug resistance in K562/A02 cells can be associated with [Ca(2+)]i increase and upregulation of MAGE-3 expression.

Antigens, Neoplasm↗
PubMed2005

[The differential features of bone marrow morphology of several rare infectious disorders].

OBJECTIVE: To facilitate the diagnosis of histoplasmosis, kala-azar, penicilliosis marneffei, toxoplasmosis and cryptococcosis with the help of bone marrow morphology. METHOD: The clinical features and bone marrow cytomorphology in 7 cases of histoplasmosis, 1 case of kela-azar, 1 case of penicilliosis marneffei, 2 cases of toxoplasmosis and 3 cases of cryptococcosis were studied. RESULTS: In the bone marrow examination, the form of histoplasma capsule was ovoid with a colorless circle. The morphology of Leishmania donovani was similar to that of histoplasma capsule except that there were terkinetoplasts present in the former. Sausage form and central cross wall were signs of Penicillium marneffei. Toxoplasma gondii looked like a banana and cryptococcus neoformans was larger than the others and had a thick capsule. CONCLUSION: The examination of bone marrow is important to the diagnosis of these rare infectious diseases.

Adult↗
PubMed2005

[Effects of PLK1 gene silence on apoptosis of K562 cells].

OBJECTIVE: To investigate the effects of PLK1 gene silence by short hairpin RNA (shRNA) on PLK1 expression and apoptosis in K562 cells, and explore the role of PLK1 in the pathogenesis of leukemia. METHODS: The shRNA fragment targeting at 1416-1436 bp of PLK1 mRNA was synthesized and cloned into pEGFP-H1 vector, named as pEGFP-H1/PLK1. The empty control, pEGFP-H1 and pEGFP-H1/PLK1 were transfected into K562 cells respectively via electroporation. 24 h or 48 h after transfection, gene and protein expression of PLK1 in the cells were assayed by RT-PCR and Western blot analysis respectively, cells viability by MTT assay, caspase-3 activity by colorimetry, cell cycle and apoptosis by FACS. RESULTS: 24 and 48 h after transfection, PLK1 expression in K562 cells was 1.25 +/- 0.07 for control group, 0.52 +/- 0.04 and 0.25 +/- 0.02 for pEGFP-H1/PLK1 group, and 1.24 +/- 0.08 and 1.23 +/- 0.09 for pEGFP-H1 group respectively. The alteration status of PLK1 protein levels were similar to that of PLK mRNA levels. The apoptosis rate was (8.3 +/- 0.6)% in control group, (8.7 +/- 0.7)% in pEGFP-H1 group and (49.7 +/- 3.8)% and (82.3 +/- 6.9)% in pEGFP-H1/PKLK1 group at 24 and 48 h, respectively. In addition, cell fraction at G(2)/M phase was increased obviously compared with control and pEGFP-H1-transfected group. CONCLUSION: The constructed shRNA can remarkably inhibit PLK1 expression and transfected K562 cell proliferation, increase apoptosis and block cell-cycle, suggesting that PLK1 play important roles in apoptosis and cell-cycle control of leukemia cells.

Apoptosis↗