Figure 2.

Induction of apoptosis by K2CrO4 on a bronchoalveolar carcinoma isogenic H358 cell line system. (A) Internucleosomal DNA fragmentation; cells were treated with 200 μM of K₂CrO₄ in SGM for 2 h, washed, and then incubated in drug-free medium for additional time periods. Finally, cells, including those floating and adherent, were collected. Lanes: M: marker; C: control. Data are representative of three replicate experiments yielding similar results. (B) Evidence of apoptosis was identified by staining with annexin V (Roche Diagnostic, Indianapolis, IN) (x axis) and propidium iodide (PI) (y axis). Cells were treated as in (A) and analyzed after 24 h of recovery. Cells were washed in PBS and resuspended in 100 μl binding buffer containing annexin V. Cells were analyzed by flow cytometry after the addition of PI. Cells binding annexin V and retaining PI were apoptotic (lower right quadrant); double-positive cells underwent secondary necrosis (upper right quadrant). Data are representative of three replicate experiments yielding similar results.