Shuang-Fen Tao

Publications (2)7.33 Total impact

• Article: Anti-tumor effect of 5-aza-2'-deoxycytidine by inhibiting telomerase activity in hepatocellular carcinoma cells.

  Shuang-Fen Tao, Chang-Song Zhang, Xian-Ling Guo, Yun Xu, Shan-Shan Zhang, Jian-Rui Song, Rong Li, Meng-Chao Wu, Li-Xin Wei
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  ABSTRACT: To investigate the effect of the demethylating reagent 5-aza-2'-deoxycitidine (DAC) on telomerase activity in hepatocellular carcinoma (HCC) cell lines, SMMC-7721 and HepG2. The related gene expression in cell lines was examined by real-time reverse transcription-polymerase chain reaction and Western blotting analysis. The telomerase activity was examined by telomeric repeat amplification protocol-enzyme-linked immunosorbent assay and DNA methylation was determined by methylation-specific polymerase chain reaction. The telomerase activity was significantly reduced in both cell lines treated with DAC, accompanied by downregulation of telomerase reverse transcriptase (hTERT). We also observed the effect of DAC on the methylation status of hTERT promoter and the expression of regulatory genes, such as c-myc, p15, p16, p21, E2F1, and WT1. The methylation status of hTERT promoter could be reversed in SMMC-7721 by DAC, but not in HepG2 cells. However, p16 expression could be reactivated by demethylation of its promoter, and c-Myc expression was repressed in both cell lines. Moreover, DAC could enhance the sensitivity to the chemotherapeutic agents, such as cisplatin, by induction of apoptosis of HCC cells. The DAC exerts its anti-tumor effects in HCC cells by inhibiting the telomerase activity.
  World Journal of Gastroenterology 05/2012; 18(19):2334-43. · 2.47 Impact Factor
• Article: Autophagic cell death induced by 5-FU in Bax or PUMA deficient human colon cancer cell.

  Hai-yan Xiong, Xian-ling Guo, Xin-xin Bu, Shan-shan Zhang, Nan-nan Ma, Jian-rui Song, Fei Hu, Shuang-fen Tao, Kai Sun, Rong Li, Meng-chao Wu, Li-xin Wei
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  ABSTRACT: Autophagy is a membrane process that results in the transporting of cellular contents to lysosomes for degradation. Autophagic cell death is another way of programed cell death called type II PCD, which has complicated connection with apoptosis, both of these two types of cell death play an important role in tumor development. In this study, we investigated chemotherapeutic agent induced cell death pathway in wild type (WT), Bax(-/-) and PUMA(-/-) HCT116 cells. Bax or PUMA deficient cells had similar chemosensitivity to WT cells but were defective in undergoing apoptosis. The results of electron microscopy and GFP-LC3 localization assay showed that autophagy was induced in Bax or PUMA deficient cells but not in WT cells. mTOR activity was decreased in Bax or PUMA deficient cells which further indicated the up-regulation of autophagy. Inhibition of autophagy by 3-Methyladenine (3-MA) decreased the cell death in Bax or PUMA deficient cells. Taken together, these results suggest that autophagic cell death can be used as an alternative cell death pathway in apoptosis defective cells and may bring a new target for cancer therapy.
  Cancer letters 09/2009; 288(1):68-74. · 4.86 Impact Factor