[Alteration of activities of telomerase in tanshinone IIA inducing apoptosis of the leukemia cells].

OBJECTIVE: 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. METHOD: 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. RESULT: 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. CONCLUSION: Tan IIA could significantly inhibit the proliferation and telomerase activities of HL-60 and K562 cells and induce the leukemia cell apoptosis.

[Enhancement of the bystander effect by tanshinone IIA in HSV-tK/GCV system is related to expression of connexin 43 mRNA].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Reversing effect of Tanshinone on malignant phenotypes of human hepatocarcinoma cell line.

AIM:To study the reversing effect of Chinese drug tanshinone on malignant phenotype of cancer cells.METHODS:Human hepatocarcinoma cell line (SMMC-7721) was treated in vitro with 0.5mg/L tanshinone for 4 days, and variation in cell differentiation wasdetected.RESULTS:The morphology of cancer cells was tended toward well differentiation and cell growth was markedly inhibited. BrdU uptake assay and immunohistochemical stain of PCNA showed that the BrdU labeling rate and PCNA positive rate were lower than the controls, but no difference was found statistically as compared with all transretinoic acid.Flow cytometric assay demonstrated that S phase cells decreased and G(0)/G(1) phase cells increased. Expression of c-myc oncogene protein decreased but the c-fos oncogene protein markedly increased. CONCLUSION:Tanshinone could reverse the inducing differentiation in human hepatocarcinoma cells (SMMC-7721). It may become a new prospective inducer of cell differentiation to treat cancers.