PMC

Monolayers of MCF-7 and MEC-1 cells cultured in low-serum medium and treated or not with extracellular Tat_101aa (100 ng/ml for 36 hours). Increased numbers of cells can be observed in Tat-treated cultures as compared to untreated control cultures. Phase contrast; microscopic fields taken with a 10× objective.

Growth of mammary epithelial cells exposed to different doses of Tat_101aa. Cells were cultured in low-serum medium. Growth was measured by the XTT assay after 48 h of Tat treatment. Each bar represents the average of 3 different tests + SD. *, P < 0.05, as compared with untreated cell cultures.

Semiquantitative RT-PCR of VEGF family genes in MCF-7 cells cultured in low-serum medium and exposed for different times to extracellular Tat_86aa. Increased expression of the VEGF receptor-2 (Flk-1/KDR) and VEGF isoform 165. To a lower extent, the VEGF isoform-121 was also up-regulated. The GAPDH signal was used as a control. MW, DNA molecular weight ladder.

Neutralization by anti-Tat antibodies of the proliferative response to Tat of five different human epithelial cell lines cultured in low-serum medium. Cells were either left untreated (open bars) or exposed to 100 ng/ml Tat_86aa (closed bars) at time 0. Cells were counted by microscopy at day-0, -1 and -2 after plating. Antibody tMAb-B (1 μg/ml) was mixed with Tat before treatment (red bars) or given alone (green bars). Bars represent the mean of three wells. Experiments on AV-3 cells (bottom panel) have also demonstrated the Tat-neutralizing activity of a rabbit polyclonal anti-Tat antibody: anti-Tat plus Tat (yellow bars) and anti-Tat alone (gray bars). Results are expressed as number of cells/well. Each bar represents the average of 3 different tests. Standard deviations of the mean are not reported, but were within 12% of the mean.