ABSTRACT
Objective:To study the influence of protein transduction domain (PTD)-oligomerization domain (OD)-HA fusion proteins on apoptosis of bcr/abl-positive cell lines. Methods:bcr/abl-positive cells were treated with PTD-OD-HA protein. The apoptoses of the cells were detected by flow cytometry (FCM), DNA ladder and transmission electron microscopy (TEM), and the levels of apoptosis-related genes bax and bcl-2 were detected by RT-PCR and Western blotting. Results:FCM examination demonstrated that PTD-OD-HA protein induced the apoptosis of bcr/abl-positive cells; DNA ladder showed that the classic DNA ladders appeared in BaF3-P210 and K562 cells after 48 h treatment with PTD-OD-HA proteins; the apoptoses of BaF3-P210 cells were observed by TEM; the levels of bax in mRNA and protein increased in BaF3-P210 and K562 cells, and bcl-2 decreased. Conclusion:PTD-OD-HA proteins specifically induced the apoptosis of bcr/abl positive cells.
ABSTRACT
Objeetive To construct the cell DNA damage models for the human CML K562 cell line before or after imarlnib mesylate treatment and observe the repairing process dynamically for investigating the iniluence of imatinib mesylate on the repair function of K562 cells after cell DNA danlage.Methods The MTT assay was used to estimate the optimal pretreatment concentration of imatinib mesylate in K562 cells and Western blot was employed to evaluate the phosphorylation status in K562 cells after imatinib mesylate treatment to estimate BCR/ABL tyrosine kinase inhibition by imatinib mesylate.The comet assay was used to detect the DNA damage induced by hydrogen peroxide at various concentrations in K562 cells with or without the pretreatment of imatinib mesylate.A dynamic observation on the repairing process after cell DNA damage was made by the comet assay.Results The pretreatment by imatinib mesylate for K562 cells was optimized to be at a final concentration of 1 μmol/L for 24 h as revealed by the MTT assay additionly imatinib mesylate treatment at this concentration could effectively inhibit the phosphorylation of the BCR-ABL fusion protein at Tyr177(Deusityrate 0.100±0.018).When compared with the control group(Deusityrate 0.425±0.039),the BCR/ABL phosphorylation at Tyr177 was significantly decreased by (77. 11±5.59) % (t=4. 57,P＜0. 05). The cell DNA damage models for both imatinib mesylate-nontreated and imatinib mesylate-pretreated K562 cell groups were constructed with hydrogen peroxide treatment at a final concentration of 10 μmol/L for 10 min at 4℃ as confirmed by the comet assay. When compared with the control imatinib mesylatenontreatod K562 cell group,the time duration required for the DNA repair in imatinib mesylate-pretreated K562 cell group was significantly prolonged (F= 97.79,P＜0. 05 ). Conclusions The cell DNA damage models for the leukemic K562 cell groups before or after imatinib mesylate treatment were successfully constructed and the tyrosine kinase inhibitor imatinib mesylate for BCR/ABL fusion protein was revealed to attenuate the DNA repair capacity of the K562 cells after DNA damage.
ABSTRACT
Objective To construct the transformed mouse BaF3-P210 cell line stably expressing BCR/ABL and to initially investigate the influence of BCR/ABL on the cell biological characteristics of BaF3 cell line. Methods The retroviral vector with bcr/abl gene was transfected into the packaging cell line. The BaF3 cells were infected with the collected viral supernatant. The transgenic BaF3-P210 cell line stably expressing BCR/ABL were screened and subcloned. The integration of the bcr/abl gene in the genome of the target cell was determined by PCR and DNA sequencing,trypan blue staining assay,flow cytometry and MTT assay. Results The bcr/abl gene was integrated into the BaF3 cell genome; RT-PCR and Western blot verified the stable expression of the bcr/abl gene and protein in the screened subclone cell line BaF3-P210. Compared with the control group,the cell proliferation rate was promoted (P
ABSTRACT
Objective To construct double expression retroviral vectors targeting chronic myeloid leukemia (CML) b3a2-type mRNA and investigate its effect on the phenotype of K562 cells. Methods The eGFP coding sequence was inserted into the retroviral vector pMSCV-neo to construct pMSCV/GFP, then H1-RNA pol III-based transcription cassettes was subcloned into it to form pMSCV/GFP-H1-BCR/ABL40AS. Two control vectors pMSCV/GFP-H1-BCR/ABL40S & pMSCV/GFP-H1-BCR/ABL80AS were constructed in addition. All these constructions were identified by restriction enzyme analysis and DNA sequencing. After that, the recombinant vectors were transferred into retrovirus packaging cell line PT67 by using lipofectamine2000, and G418 were used to select stable virus-producing cell lines. Viral titer was determined by infection of NIH3T3 cells sequentially. The cell-growth curve was assayed, cell apoptosis was checked with Annexin V-PE/7AAD double staining and flow cytometry analysis after 24-hour infection, the PKR phosphorylation was assayed by Western blotting. Results The plasmids were successfully constructed. Four cell lines, named as PT67-MSCV/GFP, PT67-40as, PT67-40s and PT67-80as were gained by G418 selection, and virus titers were 6.2?10~ 5 , 5.6?10~ 5 , 4.6?10~ 5 and 6.0?10~ 5 CFU/ml respectively. PT67-40as suspensions could induce K562 cell apoptosis by (22.54?3.19)%, significantly different from PT67-MSCV/GFP or PT67-40s (P
ABSTRACT
Objective:To research the expression of HBsAg DNA vaccine in immunized mice.Methods:The expression of HBsAg DNA vaccine was detected by immunohistochemistry staining in muscle fibers,lymphoid nodes and spleens of mice after intramuscular injection.Anti-HBsAg antibody was assayed by ELISA and the proliferation of spleen cells was measured by MTT.Results:The positive expression was observed in the tissues mentioned above.The titer of serum antibody showed positive results.Spleen cells could be proliferated by stimulating with HBsAg or ConA.Conclusion:The positive expression and certain kinds of immune responses have been shown in immunized mice.
ABSTRACT
Objective To investigate the effects of circadian clock gene Period2(Per2)on the proliferation,differentiation and apoptosis of K562 cells and its probable molecular mechanism.Methods The Per2 expression plasmid pcDNA3.1-Per2 and empty control plasmid were respectively transfected into K562 cells with cationic liposome,and the resistant cells stably expressing Per2 gene were obtained by G418 selection.Their morphological changes were observed under light microscope following Wright-Giemsa staining.Trypan blue excluding staining and MTT assay were employed to evaluate cell proliferation.Flow cytometry was performed to analyze cell cycle distribution and cell apoptosis,and electron microscopy was used to detect cell apoptosis.Meanwhile,the expressions of proliferation and apoptosis associated proteins,such as P53,Cyclin B1 and C-Myc,were respectively detected by RT-PCR and Western blot analysis at mRNA and protein level.Results The K562/Per2 cell line stably expressing Per2 gene was screened out.As compared with either the empty plasmid transfected group(K562/empty)or the untreated group(K562/untreated),K562/Per2 cells was smaller in volume and showed no obvious cellular differentiation.Circadian clock gene Per2 could significantly inhibit both growth and proliferation of K562 cells.The percentage of K562 cells in G2/M phase increased [K562/Per2 group(36.1?5.5)%,K562/empty group(12.5?2.9)%,untreated group(9.7?2.3)%,P