Chinese hamster ovary cells (CHO) are preferable to prokaryotic, yeast or insect cells as hosts for biopharmaceutical production due to the products are more similar to their natural conformation. However, CHO cells confront tremendous difficulties when cultured in large scale such as mal-adaptation to serum-free medium, apoptosis and over-growth without limitation. So in addition to optimizing CHO system in respect of medium, environment and expression vector, modification of CHO cells themselves has drawn more and more attention. Here the main progress in CHO-modification is reviewed.
Animals ; Apoptosis ; genetics ; CHO Cells ; drug effects ; metabolism ; Cell Cycle ; drug effects ; Cell Cycle Proteins ; drug effects ; Cell Division ; drug effects ; Cricetinae ; Genetic Vectors ; genetics ; Transfection

OBJECTIVETo study the antitumour effects of sodium valproate (VPA) on the proliferation, differentiation and cell cycle of Molt-4 cell and to investigate its demethylation mechanisms.

METHODSAfter Molt-4 cells trated with VPA at different concentrations, cell viability and growth curve were assessed by MTT assay. Cell cycle changes were analyzed by flow cytometry. The expression level of p15, DNA methyltransferase 1 (DNMT-1), DNMT3A and 3B mRNA were detected by RT-PCR and the methylation level was detected by hn-MSPCR.

RESULTSVPA significantly inhibited the proliferation of Molt-4 cells. After 48 h culture with 5.0 mmol/L VPA, the percentages of Molt-4 cells in G(0)/G(1) phase was (66.87 ± 3.31)% and in S phase was (8.47 ± 2.56)%, while in control group, the cells in G(0)/G(1) phase increased and in S phase decreased significantly. The p15 gene in Molt-4 cells failed to express due to its hypermethylation. The expression level of p15 gene mRNA increased significantly after exposure to VPA for 48 h. As compared with control group, the expression of DNMT-1 was down-regulated in a dose-dependent manner. The expression level of DNMT3B decreased at 10.0 mmol/L concentration.

CONCLUSIONVPA has a demethylation effect on p15 INK4B gene by inhibiting the DNMT-1 and DNMT3B gene activities to recover p15 gene activity, which arrests Molt-4 cell in G(0)/G(1) phase.

Cell Cycle ; drug effects ; Cell Line, Tumor ; DNA Methylation ; drug effects ; RNA, Messenger ; genetics ; Valproic Acid ; pharmacology

OBJECTIVETo study the effect of safflower injection on the proliferation and apoptosis of human leukemia cell line HEL and the relevant molecular mechanisms.

METHODSHEL cells were treated with different concentrations of safflower injection. HEL cells without safflower injection treatment were used as the control group. MTT method was used to detect the inhibitory rate of the HEL cells at 24, 48 and 72 hours after various concentrations of safflower injection treatment (10, 20, 30, 40 and 50 mg/mL). The cell cycle and apoptosis were detected using flow cytometry and the HOXB3-mRNA expression was measured by RT-PCR at 48 hours after safflower injection treatment (10, 20 and 30 mg/mL).

RESULTSCompared with the control group, various concentrations of safflower injection inhibited HEL cell proliferation in a dose-dependent manner (P<0.05). At 48 hours after various concentrations of safflower injection treatment, the number of treated cells in the G2/M phase increased, but that in the S phase decreased, and the apoptosis rate was significantly higher than that in the control group, with a dose-dependent manner (P<0.05). The expression of HOXB3-mRNA in safflower injection-treated cells decreased in a dose-dependent manner compared with the control group (P<0.05).

CONCLUSIONSSafflower injection can inhibit proliferation and induce apoptosis of HEL cells in vitro, and its underlying mechanisms may involve down-regulation of the HOXB3-mRNA expression.

Apoptosis ; drug effects ; Carthamus tinctorius ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Homeodomain Proteins ; genetics ; Humans ; Injections ; Leukemia ; drug therapy ; metabolism ; pathology

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

OBJECTIVETo investigate the effect of the RNAi and the chemotherapy drugs nolatrxed on the expression of thymidylate synthase(TS) and the growth of the colorectal carcinoma LOVO cells.

METHODSThe siRNA was constructed targeting the human TS gene, and then transfected into the human colorectal cancer LOVO cells. RT-PCR and Western blot technique were used to observe the TS gene and protein expression levels, and MTT was used to detect cell proliferation after silencing the TS gene. In addition, siRNA and nolatrxed were applied to the LOVO cells to observe the TS protein expression and cell growth.

RESULTSTS siRNA significantly reduced the expression of TS gene and protein in LOVO cells, and inhibited cell growth. The IC50 value of LOVO cells was (1.46±0.25) μmol/L in TS siRNA combined with nolatrexed group, (6.81±0.31) μmol/L in the negative control group, and (6.47±0.43) μmol/L in the single nolatrexed group. After treatment of TS siRNA combined with nolatrexed on LOVO cells for 36 hours, the apoptosis index was higher than that in single TS siRNA and nolatrexed[(62.12±0.89)% vs.(21.56±0.67)% and(40.51±0.83)%, both P<0.05].

CONCLUSIONTS siRNA can partly suppress the expression of TS gene in LOVO cells, inhibit cell proliferation, promote cell apoptosis and enhance cell sensitivity to apoptosis induced by nolatrexd.

Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Colorectal Neoplasms ; enzymology ; pathology ; Humans ; Quinazolines ; pharmacology ; RNA Interference ; Thymidylate Synthase ; genetics ; metabolism

The defect or block of apoptosis is an important factor involved in the drug resistance of tumor cells. Blm gene plays a great role in DNA damage and repair. This study was aimed to explore the relationship of blm gene expression with cell cycle and apoptosis after Jurkat DNA damage. The apoptosis rate and change of cell cycle were detected by flow cytometry, the expression level of blm mRNA in Jurkat cells was determined by semi-quantitative RT-PCR. The results indicated that after induction with 0.4 g/L of mitomycin C (MMC) for 24 hours the apoptosis rate of Jurkat cells were (11.42±0.013)%, and (66.08±1.60)% Jurkat cells were arrested in G2/M phase. After induction for 48 hours, the apoptosis rate of Jurkat cells declined from (11.42±0.013)% to (8.08±0.27)%, and cell count of Jurkat cells arrested in G2/M phase decreased from (66.08±1.60)% to (33.96±1.05)%. When induced with 0.4 g/L of MMC for 24 hours, the apoptosis rate of fibroblasts and the percentage of fibroblasts in G2/M, G0-G1 and S phase all showed no significant change until 48 hours. The range of apoptosis rate and the change of cell percentage in three phases were significantly different between Jurkat cells and fibroblasts (p<0.01). Expression level of blm mRNA in Jurkat cells was remarkably higher than that in normal fibroblasts (p<0.01), at 48 hours expression level of blm mRNA was remarkably higher than that at 24 hours. The 2 groups showed clear difference of blm mRNA expression after treated by MMC (p<0.01). It is concluded that the blm gene may play a significant role in repair of DNA damage of Jurkat cells after MMC induction. Abnormal expression of blm is correlated to the drug resistance of leukemia cells.
Apoptosis ; Cell Cycle ; DNA Damage ; drug effects ; DNA Repair ; drug effects ; Humans ; Jurkat Cells ; Mitomycin ; pharmacology ; RecQ Helicases ; genetics

OBJECTIVETo study the effect of laminarin sulphate (LAMS) on the expressions of PTEN and P27kip1 in androgen-independent prostate cancer PC-3 cells in vitro, and investigate the mechanism of its anti-tumor action.

METHODSThe inhibitory effects of different concentrations of LAMS (0, 50, 100, 200 microg/ml) on androgen-independent prostate cancer PC-3 cells were detected by WST-8 assay. The morphology of PC-3 cells was observed under the fluorescence microscope, and the cell cycle and apoptosis were analyzed by flow cytometry. The mRNA and protein levels of PTEN and P27kip1 were measured by RT-PCR and Western blot.

RESULTSLAMS inhibited the proliferation of androgen-independent prostate cancer PC-3 cells in a dose- and time-dependent manner, and the cell cycle analysis showed that PC-3 cells were arrested in the S phase after treated with different concentrations of LAMS. The rate of apoptosis was increased and many typical apoptotic morphological features were observed under the fluorescence microscope. The PTEN and P27kip1 expressions at mRNA and protein levels were increased in a dose-dependent manner.

CONCLUSIONLAMS can inhibit the proliferation, arrest the cell cycle in the S phase and induce apoptosis of prostate cancer PC-3 cells. The significantly increased expressions of PTEN and P27kip1 may be one of the mechanisms for LAMS inhibiting prostate cancer PC-3 cells.

Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Line, Tumor ; drug effects ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinase Inhibitor p27 ; genetics ; Humans ; Male ; PTEN Phosphohydrolase ; genetics ; Polysaccharides ; pharmacology ; Prostatic Neoplasms ; blood ; genetics ; RNA, Messenger ; genetics

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 investigate the effect of curcumin (Cur) on radiosensitivity of nasopharyngeal carcinoma cell CNE-2 and its mechanism.

METHODThe effect of curcumin on radiosensitivity was determined by the clone formation assay. The cell survival curve was fitted by Graph prism 6. 0. The changes in cell cycle were analyzed by flow cytometry (FCM). The differential expression of long non-coding RNA was detected by gene chip technology. Part of differentially expressed genes was verified by Real-time PCR.

RESULTAfter 10 micro mol L-1 Cur had worked for 24 h, its sensitization enhancement ratio was 1. 03, indicating that low concentration of curcumin could increase the radiosensitivity of nasopharyngeal carcinoma cells; FCM displayed a significant increase of G2 phase cells and significant decrease of S phase cells in the Cur combined radiation group. In the Cur group, the GUCY2GP, H2BFXP, LINC00623 IncRNA were significantly up-regulated and ZRANB2-AS2 LOC100506835, FLJ36000 IncRNA were significantly down-regulated.

CONCLUSIONCur has radiosensitizing effect on human nasopharyngeal carcinoma CNE-2 cells. Its mechanism may be related to the changes in the cell cycle distribution and the expression of long non-coding IncRNA.

Cell Cycle ; drug effects ; radiation effects ; Cell Line, Tumor ; Cell Survival ; drug effects ; radiation effects ; Curcumin ; pharmacology ; Gene Expression Regulation, Neoplastic ; drug effects ; radiation effects ; Humans ; RNA, Long Noncoding ; genetics ; Radiation Tolerance ; drug effects

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