A comparison of radiosensitization by etanidazole and pimonidazole in mouse tumors

Characterization of phytochemicals and evaluation of anti-cancer potential of Blumea eriantha DC

The aim of the present study was to evaluate the in vitro anti-cancer and anti-oxidant potential of methanol extract of Blumea eriantha as well as its phytochemical characterization. The in vitro cytotoxic and antiproliferative activities of B. eriantha methanolic extract of leaves were evaluated using MTT assay on HeLa and B16F10 cell lines, and wound scratch and colony formation assays on B16F10 cell lines. The expressions of p53 and Bcl-2 genes were also determined by reverse transcriptase-polymerase chain reaction to establish apoptosis. Isolation and identification of chemical constituents were carried out by various chromatographic and spectroscopic analytical techniques including HPTLC and LC-MS. The methanol extract of the leaves of B. eriantha showed potent in vitro antioxidant and anticancer properties. Moreover, the extract showed significant loss of wound healing, thus suggesting that it could prevent a possible metastasis. Hence, B. eriantha could be explored as a potential anticancer plant with antimetastatic properties.

Relationship between intracellular concentration and radiosensitizing effect of pimonidazole and etanidazole on two human melanoma cell lines

A study on the uptake and radiosensitizing properties of pimonidazole (PIMO) and etanidazole (ETA) was made in vitro with two melanoma cell lines: Na11+ and Na11-. The amelanotic Na11- was derived from the pigmented Na11+ cell line and was characterized by the complete absence of pigmentation in vitro. Plateau-phase cells were heavily pigmented for the Na11+ line whereas exponential cells showed a lower melanin content. Radiosensitivity was studied using an in vitro colony assay; intracellular drug concentration was determined by HPLC. For both cell lines the uptake of PIMO was always higher than the uptake of ETA, and slightly higher in hypoxia than in air. The uptake of PIMO was exceptionally high in plateau-phase cells of the pigmented Na11+ cell line. The radiosensitizing effect of ETA did not differ greatly as a function of the cell kinetics in both cell lines, whereas the radiosensitizing effect of PIMO was cell line-dependent. Sensitization of exponential cells by PIMO was similar in both cell lines but significantly less in plateau-phase cells, with the heavily pigmented Na11+ cell line being least affected, despite a three-fold increase in PIMO uptake observed in plateau cells relative to exponentially growing Na11+ cells. The uptake of PIMO may be related to the high melanin content of plateau-phase Na11+ cells and therefore this in vitro model may be useful for predicting the effects of agents such as PIMO towards melanotic melanomas in vivo.