Regulatory volume decrease is actively modulated during the cell cycle.

Nasopharyngeal carcinoma cells, CNE-2Z, when swollen by 47% hypotonic solution, exhibited a regulatory volume decrease (RVD). The RVD was inhibited by extracellular applications of the chloride channel blockers tamoxifen (30 microM; 61% inhibition), 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB, 100 microM; 60% inhibition), and ATP (10 mM; 91% inhibition). The level and time constant of RVD varied greatly between cells. Most cells conducted an incomplete RVD, but a few had the ability to recover their volume completely. There was no obvious correlation between cell volume and RVD capacity. Flow cytometric analysis showed that highly synchronous cells were obtained by the mitotic shake-off technique and that the cells progressed through the cell cycle synchronously when incubated in culture medium. Combined application of DNA synthesis inhibitors, thymidine and hydroxyurea arrested cells at the G1/S boundary and 87% of the cells reached S phase 4 h after being released. RVD capacity changed significantly during the cell cycle progression in cells synchronized by shake-off technique. RVD capacity being at its highest in G1 phase and lowest in S phase. The RVD capacity in G1 (shake-off cells sampled after 4 h of incubation), S (obtained by chemical arrest), and M cells (selected under microscope) was 73, 33, and 58%, respectively, and the time constants were 435, 769, and 2,000 sec, respectively. We conclude that RVD capacity is actively modulated in the cell cycle and RVD may play an important role in cell cycle progress.

Inhibitive Effects of Antisense Oligonucleotides of c-fos and c-jun on the Proliferation of the CNE-2Z Cells and the Expression of PKC-? / 中国肿瘤生物治疗杂志

The effects of antisense oligonucleotides of c-fos and c-jun on the proliferation of CNE-2Z cells and on the expression of protein kinase C-? (PKC-?) were investigated. With the interpoising of Lipofectin(LP), the CNE-2Z cells were added with antisens oligonucleotides of c-fos and c-jun. MTT method was used to test the cell proliferation and flow cytometry (FCM) to the PKC-a expression. The results showed that the inhibition of antisense oligonucleotides of c-fos and c-jun to CEN-2Z cells was gradually enhanced with its concentration and prolonging time increasing and that its lowest effective concentration of LP was 1.7 X 10~(-6)?g/ml, the lowest effective concentration was of antisense oligonucleotides of c-fos and c-jun 1.7 x 10~(-5)?g/ml, and the most effective time was 20 hours after treatment. The fluoresence of PKC-a and percentage of positive cells in the groups treated by antisense oligonucleotides of c-fos and c-jun decreased significantly. The results indicated that the autisense oligonucleotides of c-fos and c-jun could inhibit the proliferation of CNE-2Z ceUs the expression of PKC-?.

The effect of EBV latent membrane protein 1 on proliferation and cell cycle of nasopharyngeal carcinoma cells / 中国病理生理杂志

AIM:To investigate the effect of Epstain-Barr virus latent membrane protein 1 (EBV-LMP1) on proliferation and cell cycle of nasopharyngeal carcinoma (NPC) cells. METHODS:The expression of EBV-LMP1 was detected by immunohistochemical method (LSAB). Proliferation of NPC cells was identified by MTT method. Cell cycle percentage was detected by flow cytometry analysis. RESULTS: OD value of EBV-LMP1 expressive NPC cells L-CEN1 was much higher than that of both EBV-LMP1 negative NPC cells V-CEN1 and CNE1 ( P 0.05).CONCLUSION:The expression of EBV-LMP1 on NPC cell might cause some change of cell cycle and enhance cell proliferation.

Effects of homoharringtonine on inhibition of proliferation and induction of apoptosis of nasopharyngeal carcinoma cells CNE-2Z / 中国药理学通报

AIM To study the effects of homoharringtonine(HHT) on inhibition of proliferation and induction of apoptosis of nasopharyngeal carcinoma cells CNE 2Z. METHODS The inhibitory rates of the proliferation and IC 50 were detected by MTT method. The apoptosis was analyzed by flow cytometry (FCM), agarose gel electrophoresis and Hoechst 33258/PI fluorescence staining. RESULTS After cells were treated with HHT of different concentrations for 24, 48 and 72 h,respectively,the inhibitory rates of the proliferation rised with concentration and time. The IC 50 values of 24, 48 and 72 h were (0 629?0 039), (0 483?0 011) and (0 389?0 027) mg?L -1 , respectively. The difference among IC 50 values was obvious ( P

A study on apoptosis of lymphocytes and expression of apoptotic protein in patiens with idiopathic thrombocytopenic purpura / 中国免疫学杂志

Objective:To investigate the relations between the changes of apoptotic lymphocytes and expression of apoptotic protein and idiopathic thrombocytopenic purpura(ITP).Methods:Flow cytometry was used to detect the percentages of the apoptotic lymphocytes and the expression of Fas,FasL on peripheral lymphocytes,and the serum levels of sFas、sFasL were also determined by a sandwich enzyme-linked immunosorbent assay(ELISA),in 25 patients with ITP.Results:The percentages of the apoptotic lymphocytes(3.35?1.43) and the expression of Fas(32.17?6.54) and FasL(41.14?6.76)were all increased significantly in treated patients whose platelets recovered to normal( P