FIG. 1.

LANA2 inhibits G₂/M arrest induced by paclitaxel and prevents paclitaxel-induced microtubule polymerization. (a) MCF-7 cells transfected with EGFP or EGFP-LANA2 were treated with 10 nM paclitaxel for 24 h, stained with propidium iodide for cell cycle analysis, and subjected to flow cytometry. Numbers in lower panels show percentages of cells detected in each cell cycle phase in a representative experiment. (b) Upregulation of p53 or Foxo3a levels after treatment of MCF-7 cells with low doses of paclitaxel (10 nM) for 24 h is not detected in cells expressing LANA2. Cells were transfected and treated with paclitaxel as described above, and whole-cell lysates were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and probed for the proteins indicated. Actin serves as a loading control. The relative intensity of each band was estimated densitometrically by normalizing the values from treated cells (+) to those from untreated cells (−) (relative density, 1) and is displayed below each lane. (c) MCF-7 cells transfected with pcDNA or pcDNA-LANA2 were treated with 10 μM paclitaxel for 24 h and subsequently double-stained with anti-LANA2 and anti-tubulin antibodies and analyzed by fluorescence microscopy.