RÉSUMÉ
Objective To investigate the effect of TGF-β1/SMAD signaling pathway on K562 cells growth inhibition caused by HMBA. Methods After establishing the in vitro differentiation model with HMBA on K562 cells, the MTT assay was used to detect the proliferation of K562 cells, the cell cycle profile was detected by flow cytometry, and the mRNA expression of TGF-β1, SMAD3, SMAD4 and EVI1 was measured by RT-PCR assay. Results HMBA could inhibit the proliferation and promote the differentiation of K562 cells obviously, which was time and concentration-dependent, and the 72 h corresponding IC50, was about 2 mmol/L. Within 72 h, flow cytometry assay indicated that the ration of G0-G1 phase cells was up-regulated, and the results of RT-PCR showed that relative mRNA expression of TGF-β1, SMAD3 and SMAD4 at mRNA level was increased gradually while that of EVI1 was decreased gradually. Conclusion HMBA can inhibit K562 cells proliferation through TGF-β1/SMAD signaling pathway.
RÉSUMÉ
Objective To evaluate the positive effects of cisplatin on sensitivity of human glioma U251 to tumor necrosis factor-related apoptosis inducing ligand and to investigate the potential mechanism. Methods The expression of green fluorescent protein (GFP) in U251 which was transfected with pAdxsi-GFP-TRAIL was observed by inverted fluorescent microscope ×400) and to ascertain the MOI. The proliferation inhibition was studied by MTT method. Morphological change was detected through inverted florescent microscope and the Hoechst33342 staining assay was used to verify whether cell apoptosis could be induced or not. The cell apoptosis was also analyzed by flow cvtometry with propidium iodide staining. Semi-quantitative RT-PCR was introduced to detect the mRNA expression of apoptosis related gene.Results The expression of TRAIL mRN A was significantly upregulated after transfection. Compared with treatment group of cisplatin and TRAIL alone, the proliferation of U2S1 was significantly inhibited in the cisplatin sensitizing TRAIL group (P < 0.05 ). Nuclear shrinkage and pyknosis fragmentation were observed by Hoechst 33342 staining assay; Apoptotic peak was detected from the results of flow cvtometry and there were significant differences between the sensitizing group and the other two groups ( P < 0.05 ) ; Moreover, the relatively high expression of TRAIL, DR5, caspaseS and down - regulated survivin genes were also observed. There was no significant changes in DR4 expression. Conclusion Cisplatin could extremely enhance the sensitivity of U251 cells to TRAIL And the potential mechanism may related to the increase of TRAIL, DRS, caspaseS genes while the reduction of surivivin gene.
RÉSUMÉ
Objective To detect the proliferation inhibition and apoptosis of HL-60 cell induced by APS-1 and APS-2 isolated from Polyporus sp. M05 and to investigate its mechanism. Methods The proliferation inhibition was detected by living cells count method,and chosed proper concentration.Flow cytometry with propidium iodide staining was used to detect cell apoptosis. Semi-quantitative RT-PCR was used to detect the expression of apoptosis related gene. Results APS-1 and APS-2 could significantly inhibit the proliferation of HL-60 cells on a time and dose dependent manner. Apoptosis ratio increased to 47. 9% and 26. 8% after HL-60 cells were exposed to APS-1 and APS-2 respectively for 48 h,and the differences had statistical significance (P <0.01). After being induced by APS-1,mRNA of Bax,Fas,Caspase-3 was upregulated. And after being induced by APS-2,mRNA of Bax,Caspase-3 was upregulated,while Fas mRNA did not change. Conclusion APS-1 and APS-2 can inhibit the proliferation and induce apoptosis of HL-60 cells. Mechanism of HL-60 cell apoptosis induced by APS-1 is related to both mitochondrial pathway and Fas signaling pathway,while apoptosis induced by APS-2 is only related to mitochondrial pathway.