Alteration of activities of telomerase in tanshinone IIA inducing apoptosis of the leukemia cells / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the effect of tanshinone IIA on HL-60 and K562 cells apoptosis, and to assay the inhibition of the telomerase activities in the leukemia cell apoptosis induced by Tanshinone.</p><p><b>METHOD</b>Using the techniques of cell culture in vitro, flow cytometry and PCR-TRAP observed the telomerase activities and apoptosis of HL-60 and K562 cells which treated by Tan IIA.</p><p><b>RESULT</b>0.5 microg x mL(-1) Tan IIA could obviously inhibit HL-60 and K562 cell lines growth (P < 0.05), down-regulate c-myc, bcl-2 gene and up-regulate c-fos and p53 gene expression as well as induce leukemia cell apoptosis, the apoptotic rates of HL-60 and K562 cells were 11.8% and 21.8% respectively. The telomerase activities significant decreased, the inhibiting rates in HL60 and K562 cells were 30.8% and 50.8% respectively.</p><p><b>CONCLUSION</b>Tan IIA could significantly inhibit the proliferation and telomerase activities of HL-60 and K562 cells and induce the leukemia cell apoptosis.</p>

Enhancement of the bystander effect by tanshinone IIA in HSV-tK/GCV system is related to expression of connexin 43 mRNA / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate enhancement of the bystander effect by tanshinone IIA (Tan) in HSV-tK/GCV system and the correlation with expression of connexin 43 mRNA.</p><p><b>METHODS</b>The cytotoxic effect in HSV-tK/GCV in cervical carcinoma cell line ME180 (ME) and ME/TK was examined by MTT assays. Cx43 mRNA expression was detected by fluor-quantitative RT-PCR.</p><p><b>RESULTS</b>Tan markedly increased sensitivity of ME/TK cells for GCV in HSV-tK/GCV system. In the presence of 2 micro g/ml GCV, compared with the absence of Tan (0 mol/L), an obvious decrease in survival rate was seen at any given mixture of ME and ME/TK cells exposed to 1.3 x 10(-9) mol/L Tan. Statistics showed significant difference (P < 0.05). However, enhancement of bystander mediated cell killing occurred only in the range of Tan concentrations used (1.3 x 10(-8), 1.3 x 10(-9) mol/L). RT-PCR showed that the ratio of relative copy number of Cx43 mRNA increased by 8.83 and 8.47-fold in ME cells exposed to 1.3 x 10(-8) and 1.3 x 10(-9) mol/L Tan, respectively.</p><p><b>CONCLUSION</b>For the first time we report that in cervical carcinoma ME180 cell line, Tan possesses a remarkable enhancing role on the bystander effect in the HSV-tK/GCV system. It is associated with up-regulation of Cx43 mRNA expression.</p>