Sub-millimolar concentration of the novel phenol-based compound, 2-hydroxy benzoate zinc, induces apoptosis in human HT-1080 fibrosarcoma cells.

OBJECTIVES: To examine the effect of a novel phenolic-based compound, 2-hydroxy benzoate zinc (2HBZ), and acetylsalicylic acid (ASA) on human HT-1080 fibrosarcoma cells. MATERIALS AND METHODS: MTT assay was used to assess cell proliferation while different methods were used to detect apoptosis morphologically and immunohistochemically in Human HT-1080 fibrosarcoma cells. Apoptosis was determined by Annexine-V labelling, and caspase-3 activation. In addition, western blot was used to analyse p21, p53 and Bax and flow cytometry was to analyse the cell cycle. RESULTS: 2HBZ exhibited a more than 5-fold increase in cytotoxic potency when compared with ASA with mean LD50 values of 210 and 1100 lM respectively (P < 0.0001). The cytotoxic effects of 2HBZ were both time- and dosedependent with marked apoptosis being evident only after 24 h at concentrations as low as 200 mM. In contrast, ASA-induced apoptosis was observed only at concentrations in excess of 1000 mM at the same time point. Both 2HBZ and ASA induced caspase-3 activation in the cells, which confirmed that their cytotoxic effects were the result of apoptotic cell death. These findings were further confirmed by immunomorphological studies for the detection of apoptosis including haematoxylineosin, methyl green/pyronin Y staining and scanning electron microscopy. In addition, 2HBZ caused a marked increase in p21, p53 and Bax protein expressions and these effects were associated with an increase in G1 and G2 arrest of the cell cycle and a reduction in S-phase. CONCLUSIONS: These results demonstrate that the novel phenolic compound 2HBZ is a potent apoptosis-inducing agent in HT-1080 cells and warrants further investigation as a potential chemotherapeutic agent in primary cancer cell models.

Calcium salicylate-mediated apoptosis in human HT-1080 fibrosarcoma cells.

Salicylates are novel biologically active compounds that exhibit multiple therapeutic activities. The anti-cancer effectiveness of calcium salicylate has been investigated on human HT-1080 fibrosarcoma cell lines at relatively low concentrations (predominantly 0.4 mM) compared to those previously reported. Although low calcium salicylate concentrations did not retard tumour growth progression significantly, as measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and time-lapse assays, its cytotoxic characteristics were proven to be prominent by various morphological and immunocytological techniques. The results here demonstrate evidence for approximately 25% apoptosis after treatment with calcium salicylate, which up-regulatd the expression of p53, p21 and Bax, and down-regulated Bcl-2 in HT-1080 cells.