Figure 1.

MGMT (O6-methylguanine-DNA methyltransferase) levels and protection from TMZ (temozolomide) toxicity. (A) Protein lysates were prepared from four different melanoma cell lines and MGMT protein levels were analyzed by Western blot. Actin was used as the loading control. (B) MGMT-negative 2058 cells and MGMT-positive A375 cells were treated with increasing concentrations of TMZ in the absence or presence of 15 µM O6BG. After 12–14 days, emerging colonies were counted. Number of colonies from untreated cells was set at 100% (n ≥ 5, ±SE).