The objective of this study was to investigate the effect of hexamethylene bisacetamide (HMBA) on differentiation of HL-60 cells and its possible molecular mechanism. HL-60 cells were co-cultured with different concentrations of HMBA (0.5, 1, 2 mmol/L) for 4 days, then the proliferation was assayed by MTT at different time points. Wright-Giemsa staining was used to observe the change in morphology. Cell differentiation antigen CD11b expression and the altered distribution of cell cycle in HL-60 induced by HMBA were analyzed by flow cytometry. The expressions of c-myc, mad1, p21, p27, hTERT and HDAC1 mRNA were detected by RT-PCR. The results indicated that the proliferation of HL-60 cells was inhibited by HMBA in a time-and-dose-dependent manner. Upon 2 mmol/L HMBA treatment, the HL-60 cells arrested at G(0)/G(1) phase and differentiated into granular line in morphology, with the up-regulation of CD11b expression. The expression of c-myc and hTERT mRNA obviously down-regulated, the expression of p21, p27 and mad1 mRNA up-regulated, while there was no change of the expression of hTERT mRNA. It is concluded that effect of HMBA on the differentiation of HL-60 cells may partly contribute to switch from c-myc to mad1 expression, to up-regulate expressions of p21 and p27 mRNA, and down-regulate hTERT mRNA expression, while there is no relation with the expression of HDAC1 mRNA.
Acetamides ; pharmacology ; Antineoplastic Agents ; pharmacology ; Cell Cycle ; drug effects ; Cell Differentiation ; drug effects ; genetics ; Cell Proliferation ; drug effects ; HL-60 Cells ; Humans

Male meiosis is a complex process whereby spermatocytes undergo cell division to form haploid cells. This review focuses on the role of retinoic acid (RA) in meiosis, as well as several processes regulated by RA before cell entry into meiosis that are critical for proper meiotic entry and completion. Here, we discuss RA metabolism in the testis as well as the roles of stimulated by retinoic acid gene 8 (STRA8) and MEIOSIN, which are responsive to RA and are critical for meiosis. We assert that transcriptional regulation in the spermatogonia is critical for successful meiosis.
Animals ; Cell Differentiation/genetics* ; Humans ; Meiosis/drug effects* ; Spermatogenesis/physiology* ; Tretinoin/metabolism*

OBJECTIVETo investigate the role of Mcl-1 gene in resistance of all-trans retinoic acid (ATRA) of leukemia cells.

METHODSLong-term, intermittent and repetitive exposure of HL-60 cells to ATRA was used to establish a multidrug-resistance cell line (HL-60/ATRA). HL-60/ATRA cells were transfected with Mcl-1 small interference RNA (siRNA) by Lipofectamine 2000. Western blot was used to detect the expression of Mcl-1. The proliferation, apoptosis and differentiation were evaluated by MTT assay, in situ nick end-labeling (TUNEL) and NBT assay, respectively.

RESULTSThe HL-60/ATRA could keep its undifferentiated and proliferative status to a high concentration of ATRA (100 nmol/L) with highly expressed Mcl-1 protein (relative grey scale 0.624 +/- 0.127). Mcl-1 gene knockdown by siRNA (relative grey scale 0.267 +/- 0.086) could reverse the resistance of ATRA of HL-60/ATRA by inhibiting proliferation, and inducing differentiation and apoptosis [apoptosis rate (18.5 +/- 4.5)%].

CONCLUSIONMcl-1 gene might be involved in ATRA resistance in HL-60 cells and inhibiting its expression could be a new approach to ATRA resistance reversion.

Apoptosis ; drug effects ; genetics ; Cell Differentiation ; drug effects ; genetics ; Cell Proliferation ; drug effects ; Drug Resistance, Neoplasm ; genetics ; HL-60 Cells ; drug effects ; metabolism ; Humans ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; RNA, Small Interfering ; Tretinoin ; pharmacology

This study was aimed to investigate the effect of 5-Aza-CdR on the biological activity of human erythroleukemia cell line K562 and the expression of inhibitor of DNA binding 4 (ID4). ID4 methylation in K562 cell line was detected by methylation-specific PCR. RQ-PCR was used to analyze the expression levels of ID4 mRNA in K562 cell line treated by different concentrations of 5-Aza-CdR. Cell apoptosis rate and cell cycle were analyzed by flow cytometry. The result showed that ID4 gene methylation existed in K562 cells, ID4 mRNA expression in K562 cells treated with 5-Aza-CdR increased in a concentration-dependent manner, the difference between experimental groups was statistical significant (p < 0.01). The 5-Aza-CdR could enhance the apoptotic rate of K562 cells in time and dose-dependent manner, the apoptotic rate of K562 cells highly correlated to relative expression level of ID4 mRNA (r = 0.95). After the K562 cells were treated by 5-Aza-CdR for 48 hours, cells in G(0)/G(1) phase increased, cells in G(2)/M phase decreased along with enhancement of drug concentration. It is concluded that methyltransferase inhibitor 5-Aza-CdR can re-express the silent ID4 gene in K562 cells. The upregulation of ID4 may be a key factor to give rise to cell apoptosis, and the cell cycle of K562 cells can be arrested by 5-Aza-CdR.
Apoptosis ; drug effects ; Azacitidine ; analogs & derivatives ; pharmacology ; Cell Cycle ; Cell Proliferation ; drug effects ; DNA Methylation ; Gene Expression ; drug effects ; Humans ; Inhibitor of Differentiation Proteins ; genetics ; K562 Cells

OBJECTIVETo establish an immortalized marrow mesenchymal stem cell line to facilitate advances in cartilage engineering research.

METHODSHuman telomerase reverse transcriptase (hTERT) cDNA was transferred into primary human marrow mesenchymal stem cells (hMSC) by retroviral vector pLEGFP-C1-hTERT. Subsequently G418 resistant cell clone was screened and expanded for further studies. hMSC biomarkers and hTERT expression were confirmed by examination. Transfected hMSC was induced to differentiate into chondrocyte using TGF-P1 and dexamethasone.

RESULTSUp-regulated hTERT expression was detected in transfected hMSC. hMSC-hTERT cells could be induced to differentiate into chondrocyte. Higher telomerase activity in transfected cells was maintained for 50 population doublings so far. Collagen II could be detected in induced transfected hMSC by immunocytochemical and hybridization in situ.

CONCLUSIONSEctopic expression of hTERT can effectively immortalize hMSC in vitro. Immortalized hMSC can be induced to differentiate into chondrocyte under certain condition. It may be an ideal target of further studies in cartilage engineering.

Bone Marrow Cells ; cytology ; drug effects ; metabolism ; Cell Differentiation ; drug effects ; Cell Line, Transformed ; Chondrocytes ; cytology ; Humans ; Mesenchymal Stromal Cells ; cytology ; drug effects ; metabolism ; Telomerase ; genetics ; metabolism ; Transfection

OBJECTIVETo explore the effect of 17-allylamide-17-demethoxygeldanamycin (17AAG), a heat shock protein 90 (HSP90) inhibitor, on the growth, differentiation and apoptosis of leukemic Kasumi-1 cells.

METHODSKasumi-1 cells were treated with 17AAG at different concentrations in suspension culture. Cell proliferation was analysed by MTT assay, expression of myeloid-specific differentiation antigen and cell cycle by flow cytometry, cell apoptosis by annexin V staining, agarose gel electrophoresis and flow cytometry. KIT protein was analysed by Western blot and c-kit mRNA by RT-PCR.

RESULTS17AAG treatment caused a dose-dependent inhibition of the cell proliferation with the IC(50) of 0.62 micromol/L. A dose-dependent increase in early apoptosis occurred at 24 hours treatment and in late apoptosis at 48 hours treatment. 17AAG induced a time- and dose-dependent increase in expression of myeloid cell surface protein CD11b and CD15, a progressive decline in S-phase cell fraction and an increase in G(0)/G(1) cells. When Kasumi-1 cells were incubated with 1 micromol/L of 17AAG, KIT protein began to decrease at 2 hours and KIT protein could hardly be detected at 20 hours, but c-kit mRNA was not decreased.

CONCLUSION17AAG treatment of Kasumi-1 cells could lower KIT protein expression, inhibit cell proliferation, induce cell partial differentiation, apoptosis and accumulation in G(0)/G(1) phase.

Apoptosis ; drug effects ; Benzoquinones ; pharmacology ; Cell Cycle ; drug effects ; Cell Differentiation ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; HSP90 Heat-Shock Proteins ; antagonists & inhibitors ; Humans ; Lactams, Macrocyclic ; pharmacology ; Proto-Oncogene Proteins c-kit ; genetics ; metabolism ; RNA, Messenger ; genetics

OBJECTIVETo examine the effects of various concentration of nicotine on bone marrow stromal cells (BMSCs) proliferation and differentiation of cartilaginous in vitro.

METHODSBMSCs was obtained from femoral bone and tibia of New-Zealand albino rabbit. The cells of the 3rd generation were used in study. Different concentration of nicotine (0, 1 x 10(-7), 1 x 10(-6), 1 x 10(-5) M) were added into BMSCs. BMSCs proliferation was analyzed by MTT assay at the 1, 4, 7, 14 days. The expression of collagen type II and aggrecan as the marker genes of cartilaginous differentiation from BMSCs were detected by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTSMicroscope showed that BMSCs transformed from round to fusiform shape. The concentration of nicotine in 1 x 10(-7), 1 x 10(-6) M had a significant positive effect on cell proliferation and the expression of type II collagen in a time-dependent manner when supplemented in commonly used induction media (P<0.05). Concentrations of nicotine in 1 x 10(-7) can promote the expression of aggrecan at the 7th day after induction,and in 1 x 10(-5) M may inhibit the expression of type II collagen and aggrecan.

CONCLUSIONIt was implied that local application of nicotine at an appropriate concentration may be a promising approach for enhancing cartilaginous differentiation capacity of BMSCs in cartilage tissue engineering.

Aggrecans ; genetics ; Animals ; Bone Marrow Cells ; drug effects ; physiology ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Chondrocytes ; cytology ; drug effects ; Collagen Type II ; genetics ; Male ; Nicotine ; pharmacology ; RNA, Messenger ; analysis ; Rabbits ; Stromal Cells ; drug effects ; physiology

By using decoy-oligodeoxynucleotides (decoy-ODNS) technique, the effects of Stathmin gene on the proliferation and differentiation of in vitro cultured precartilainous stem cells (PSCs) were investigated. The Stathmin decoy-ODNs were transfected into PSCs in rats by using gene transfection technique. Under the induction of cortisol (1 micromol/L), electrophoretic mobility shift assay was used the inhibitory effects of decoy-ODNS on Stathmin gene. MTT and cytometry were used to test the cell proliferation. The expression of collagen II and V and Stathmin protein was detected by using Western blot. The results showed that Stathmin decoy-ODNs inhibited the Stathmin activity in a dose-dependent manner. When the concentration of decoy-ODNs was 10 times of standard concentration, the proliferation of PSCs was obviously suppressed and the differentiation happened. Compared to the control group, the difference was significant (P<0.05). It was concluded that decoy-ODNs could inhibit the proliferation and promote the differentiation of PSCs by antagonizing Stathmin activity.
Cartilage/*cytology ; Cell Differentiation/*drug effects ; Cell Proliferation/drug effects ; Cells, Cultured ; Oligodeoxyribonucleotides/genetics ; Oligodeoxyribonucleotides/*pharmacology ; Rats, Sprague-Dawley ; Stathmin/*genetics ; Stathmin/pharmacology ; Stem Cells/*cytology

OBJECTIVETo explore the changes in expression of WT1 gene and ration of its isomers during phorbol ester (TPA) induced differentiation of leukemia cell line K562 by fluorescence quantitative RT-PCR and analysis the relationship between different isomers and hematogenic cell differentiation.

METHODSThe degree of cellular maturation were verified by NBT reduction test and immunophenotyping. Expression of WT1 gene was determined by fluorescence quantitative RT-PCR during differentiation of K562 cell line. The relative ratio of the four splicing variants WT1 ( + / + ), WT1 ( + / - ), WT1 ( - / + ), WT1 ( - / - ) were calculated.

RESULTSDuring the differentiation of K562 cell, the NBT reduction rate and the CD9 positive rate both increased significantly (P < 0. 05). The expression of WT1 gene decreased immediately to (1.67 +/- 0.45) x 10(-3) from (4.67 +/- 1.11) x 10(-3), and then increased again to (4.64 +/- 1.53) x 10(-3) at 96 hours. The ratio of WT1 ( + / + ) was decreased gradually, from 0 hour (39.65 +/- 19.46)% to 96 hour (15.25 +/- 7.27)%. While the ratio of WT1( - / - ) was increased, from 0 hour (15.38 +/- 11.34)%, to 96 hour (37.60 +/- 11.90)%. The other two isomers ratios did not change significantly.

CONCLUSIONDuring the TPA induced differentiation of K562 cell, there are two high expression levels of WT1 gene. Before differentiation, the majority is WT1 ( + / + ), and after differentiation, is WT1 ( - / - ). It indicates that WT1 gene may activate or inhibit cell differentiation by regulating the ratio of its four splicing variants.

Cell Differentiation ; drug effects ; genetics ; Gene Expression ; drug effects ; Humans ; K562 Cells ; Phorbol Esters ; pharmacology ; Protein Isoforms ; genetics ; metabolism ; WT1 Proteins ; genetics ; metabolism

OBJECTIVEOur previous investigation demonstrated that angiotensin II could induce proliferation and differentiation of hepatic stellate cells, and also could up-regulate its extracellular matrix synthesis. The objective of this study was to determine the effects of 10(-5) mol/L angiotensin II on gene expression of hepatic stellate cells.

METHODSAfter incubation with 10(-5) mol/L angiotensin II for 48 hours, the cultured hepatic stellate cells were collected. The mRNA and total protein were obtained from cell lysate and then suppression subtractive hybridization (SSH), 2D-gel electrophoresis and MALDI-TOF mass spectrometry were used to identify these cDNAs and proteins.

RESULTSA total of 36 clones from the subtracted cDNA library were sequenced and compared to sequences in the GenBank using BLAST. Of the 36 differentially expressed gene fragments from the subtracted library, 13 differentially expressed gene fragments showed significant homology to other known proteins, such as ribosomal protein, beta-actin FE-3, leucyl-tRNA synthetase, CD147, pyruvate kinase, peroxiredoxin 1, and BAT3, while 2 other gene fragments encoding protein BC097361 and BC057380 and their functions were not disclosed. About 1110 and 1008 protein spots were detected by employing the ImageMaster 2D Platinum 4.9 proteome image analysis system in angiotensin-treated hepatic stellate cells and control cells separately. Among these spots 108 proteins were up-regulated while the other 153 proteins were down-regulated. Several up-regulated proteins were chosen to be excised and in-gel digest MALDI-TOF-MS and Database analysis showed that among the high expression proteins, there were prohibitin, RBL-NDP kinase 1.8x10(4) subunit, electron transfer flavoprotein alpha-subunit, guanine nucleotide binding protein, alpha 15, and heat shock 7.0x10(4) protein 5.

CONCLUSIONOur results suggest that the up-regulation of hepatic stellate cell mRNA influences proliferation, differentiation and apoptosis of those cells. The proteins of signal transduction, metabolizing regulation, apoptosis suppression, and fibrogenesis regulation of hepatic stellate cells were up-regulated.

Angiotensin II ; pharmacology ; Apoptosis ; Cell Differentiation ; Cell Line ; drug effects ; Cell Proliferation ; Gene Expression ; Gene Library ; Hepatic Stellate Cells ; drug effects ; metabolism ; Humans ; Proteome ; metabolism ; RNA, Messenger ; genetics