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

The aim of this study was to investigate the potential benefit of combination therapy with 5-bromotetrandrine (5-BrTet) and daunorubicin (DNR) on chronic leukemia. The apoptosis of K562/A02 cells treated by DNA, BrTet and BrTet combined with DNR for 48 hours was detected by flow cytometry; the expressions levels of survivin mRNA and protein K562/A02 cells treated by DNR, BrTet and BrTet combined with DNR and in untreated K562 cells for 48 hours were measured by RT-PCR and Western blot respectively. The results showed that the combination of BrTet with DNR increased apoptotic rate of K562/A02, down-regulated the expression levels of survivin mRNA and protein in K562/A02 cells as compared with blank control and cells treated by BrTet or DNR alone, the survivin expression in K562/A02 cells was higher than that in K562 cells. It is concluded that the combination of BrTet with DNR can effectively reverse the multidrug resistance of K562/A02 cells, promote the apoptosis of K562/A02 cells, the mechanism of which may be related with down-regulation of survivin expression. Survivin may be a target for the treatment of MDR in hematopoietic malignancies.
Apoptosis ; drug effects ; genetics ; Benzylisoquinolines ; pharmacology ; Daunorubicin ; pharmacology ; Drug Resistance, Multiple ; genetics ; Drug Resistance, Neoplasm ; genetics ; Gene Expression Regulation, Leukemic ; Humans ; Inhibitor of Apoptosis Proteins ; genetics ; K562 Cells

OBJECTIVE: To study the effects of oligodeoxynucleotides complementary Stat3 on apoptosis in laryngeal carcinoma Hep-2 cell. METHOD: Oligodeoxynucleotides complementary Stat3 was designed, which was transferred into laryngeal carcinoma Hep-2 cell by lipofection. Expression of Stat3 and p-Stat3 were detected by Western blot and PCR. MTT was used to observe the growth-inhibiting ratio. DNA ladder, AO/EB and FCM were used to observe the apoptosis of laryngeal carcinoma cell Hep-2 in vitro. RESULT: Western blot and PCR results demonstrated that oligodeoxynucleotides complementary Stat3 could significantly inhibit the expression of Stat3 and p-Stat3 in Hep-2 cell. MTT results showed that it could significantly suppress the growth of Hep-2 cell. The DNA ladder, AO/EB and FCM results showed it could inhibit the expression of Stat3 and induce the apoptosis of Hep-2 cell in a concentration-dependent manner. CONCLUSION Oligodeoxynucleotides complementary Stat3 could induce the apoptosis and suppress cell proliferation in laryngeal carcinoma Hep-2 cell.
Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Humans ; Oligodeoxyribonucleotides ; genetics ; pharmacology ; STAT3 Transcription Factor ; genetics ; Transfection

OBJECTIVETo study methylation of Id4 gene and demethylation effect of arsenic trioxide (ATO) in Raji cells.

METHODSHuman Burkitt's Raji lymphoma cells were cultared and treated with ATO at different concentrations and different time points. Methylated degree of Id4 gene was detected by methylation specificity polymerase chain reaction (MS-PCR), Id4 mRNA expression in Raji cell by reverse transcription polymerase chain reaction (RT-PCR), the growth of cell by MTT assay, and cell apoptosis and cycle distribution by Flow Cytometry (FCM).

RESULTS(1) The Id4 gene exhaustive methylation in control group, and hypermethylation in experimental group were reversed by ATO in a dose-dependent manner. (2) Id4 mRNA expression in Raji cells treated with ATO for 48 h increased gradually with ATO concentration increasing in experimental group. (3) Raji cell growth inhibited rates after different concentrations of ATO treatment for 24, 48, 72 h were 12.15% ∼ 92.17% in the experimental group (P < 0.05). (4) Apoptosis peak emerged after ATO treatment for 48 hours in experimental group, while a much lower apoptosis in control group. (5) After ATO treatment for 48 h in experiment group, the cells were arrested at G(0)/G(1) phase in a dose-dependent manner.

CONCLUSIONId4 gene presents exhaustive methylation in Raji cells. ATO can reverse the hypermethylation of Id4 gene and recover the expression of Id4 mRNA. Hypermethylation of Id4 gene is one of the reasons of Raji cells malignant proliferations.

Apoptosis ; drug effects ; Burkitt Lymphoma ; genetics ; Cell Line, Tumor ; DNA Methylation ; Humans ; RNA, Messenger ; genetics

Six 89bp primers were designed on the base of the cDNA sequence encoding the human leptin reported on the NCBI. The synthetic gene with 464bp encoding rhLep was obtained by SOE ( splicing by overlap extension) PCR. The expression vector pET22b(+)/rhLep was constructed and transformed into E. coli BL21 (DE3). The rhLep protein was expressed as inclusion bodies with the yield of more than 50% of total bacterial proteins after IPTG induction. The rhLep protein, which has a molecular weight about 16kD, was purified by Ni2+ affinity chromatography column and identified by SDS-PAGE. The MTT Assay shows that rhLep promotes EC304 cells growth at the low concentration of 10ng/mL to 30 ng/mL, and rhLep appears cytotoxic to EC304 cells with the high dose of 50ng/mL to 225ng/mL. The viability of EC304 cells decreases to 1.2% with the concentration of 225ng/mL of rhLep. The massive apoptosis of rhLep on EC304 cells is observed by AO-staining under fluorescent microscope. All these results would lay the foundation for the further study of its biological functions in vitro and in vivo.
Apoptosis ; drug effects ; Escherichia coli ; genetics ; Humans ; Leptin ; genetics ; pharmacology ; Recombinant Proteins ; biosynthesis ; isolation & purification ; pharmacology

Gap junctions mediate direct communication between cells; however, toxicological cascade triggered by nonessential metals can abrogate cellular signaling mediated by gap junctions. Although cadmium (Cd) is known to induce apoptosis in organs and tissues, the mechanisms that underlie gap junction activity in Cd-induced apoptosis in BRL 3A rat liver cells has yet to be established. In this study, we showed that Cd treatment decreased the cell index (a measure of cellular electrical impedance) in BRL 3A cells. Mechanistically, we found that Cd exposure decreased expression of connexin 43 (Cx43), increased expression of p-Cx43 and elevated intracellular free Ca2+ concentration, corresponding to a decrease in gap junctional intercellular communication. Gap junction blockage pretreatment with 18β-glycyrrhizic acid (GA) promoted Cd-induced apoptosis, involving changes in expression of Bax, Bcl-2, caspase-3 and the mitochondrial transmembrane electrical potential (Δψm). Additionally, GA was found to enhance ERK and p38 activation during Cd-induced activation of mitogen-activated protein kinases, but had no significant effect on JNK activation. Our results indicated the apoptosis-related proteins and the ERK and p38 signaling pathways may participate in gap junction blockage promoting Cd-induced apoptosis in BRL 3A cells.
Animals ; Apoptosis/*drug effects ; Cadmium/*toxicity ; Calcium/metabolism ; Cell Communication/drug effects ; Connexin 43/genetics ; Enzyme Activation/drug effects ; Gap Junctions/*drug effects ; Gene Expression Regulation/drug effects ; Hepatocytes/cytology/*drug effects ; Rats ; Signal Transduction/drug effects

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

OBJECTIVETo investigate the effects of emodin on apoptosis induction and proliferation inhibition in human apoptosis and on c-myc protein and mRNA expression in human myeloid leukemia cell line HL-60 cells.

METHODSHL-60 cells were exposed to emodin at different dosages. Growth inhibition was detected by MTT assay and colony formation assay, and cell apoptosis by flow cytometry, TUNEL labeling method, DNA fragmentation and MitoCapture apoptosis detection. The expression of c-myc was detected by RT-PCR and Western-blot.

RESULTSEmodin remarkably inhibited the cell proliferation, with an IC(50) value of 20 micromol/L. HL-60 cells apoptosis could be efficiently induced by emodin in a dose dependent manner. The c-myc protein and mRNA expressions on HL-60 cells were decreased after emodin treatment.

CONCLUSIONEmodin could efficiently induce growth inhibition and apoptosis in HL-60 cells. c-myc may be involved in this process.

Apoptosis ; drug effects ; Cell Proliferation ; drug effects ; Emodin ; pharmacology ; HL-60 Cells ; drug effects ; Humans ; Proto-Oncogene Proteins c-myc ; genetics ; metabolism ; physiology ; RNA, Messenger ; genetics

The objective of this study was to establish an RNAi approach that can specifically target aqp1 gene sequence in vitro, and to assess the inhibitory effect of this siRNA on K562 cells. The siRNA targeting aqp1-mRNA was designed and transfected into K562 cells by using Lipofectamine(TM) 2000 reagent. Phase-contrast microscopy was used to analyze morphology changes of K562 cells. Cell viability was determined by MTT assay, and flow cytometry and DNA ladder analysis were carried out to identify siRNA-induced apoptosis. The expression levels of aqp1-mRNA at different transfection time were detected by RT-PCR. The results showed that the siRNA was successful by established. The transfected K562 cells displayed the significant apoptosis. The aqp1-siRNAs could obviously inhibit the activity of K562 cells. Cellular DNA fragmentation was observed in the siRNA group after transfection for 48 hours, the apoptosis rates at 24, 48 and 72 hours after transfection were 24.2%, 36.1% and 42.9% respectively. The aqp1-mRNA expression in the cells treated by aqp1-siRNA for 24, 48 and 72 hours were significantly reduced by 33%, 46% and 57% respectively. It is concluded that the aqp1-siRNA can efficiently and specifically inhibited the proliferation and inducing apoptosis of K562 cells. Gene aqp1 can be a potential target point for therapy of malignant tumor.
Apoptosis ; drug effects ; Aquaporin 1 ; genetics ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Gene Targeting ; Humans ; K562 Cells ; RNA Interference ; RNA, Small Interfering ; genetics ; pharmacology

BACKGROUND AND OBJECTIVEIt was proven that Vitamin C could inhibit the growth of many types of tumors as an antioxidant. The aim of this study is to explore role of Vitamin C in proliferation and apoptosis of lung carcinoma cell line A549 and the underlying mechanism.

METHODSA549 cells were cultured in vitro and incubated with Vitamin C. The cell viability was measured by growth curve and clonogentic assay. Flow cytometry was used to analyze cell cycle and detect apoptosis. The levels of expression of Caspase-3 mRNA and Survivin mRNA were detected by RT-PCR.

RESULTSVitamin C of 400 microg/mL, 4 mg/mL significantly inhibited the growth of A549 cell lines (P = 0.024, P = 0.015, respectively). Flow cytometry showed that the cells major stagnation stayed in the G0/G1 and S phase and the apoptotic rate increased with time prolonged. Vitamin C signifiantly up-regulated the expression of Caspase-3 mRNA, but had no effect on Survivin mRNA.

CONCLUSIONVitamin C can inhibit the proliferation of A549, block A549 cells in G0/G1 and S phase, and induce apoptosis of A549 cells. Apotosis occurred by up-regulated the expression of Caspase-3.

Apoptosis ; drug effects ; genetics ; Ascorbic Acid ; pharmacology ; Caspase 3 ; genetics ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Flow Cytometry ; Gene Expression Regulation, Neoplastic ; drug effects ; genetics ; Humans ; Inhibitor of Apoptosis Proteins ; Microtubule-Associated Proteins ; genetics ; Reverse Transcriptase Polymerase Chain Reaction