Figure 1.

Selection of a compound that sensitizes cells to Paclitaxel (PTX). (A) Schematic illustration of the concept used to screen a chemical library for compounds that sensitize cells to PTX. Treatment of cells with compounds of the library alone (5 μM) or PTX (1 nM) alone has no effect on cell viability, compounds (5 μM) that have no effect when applied alone but induced cell death when applied in combination with PTX (1 nM) were selected. (B) Chemical structure of Carba1. (C) Effect of Carba1/PTX combinations on the viability of HeLa cells. Cells were incubated for 72 h with the indicated combinations of Carba1/PTX. The percentage of viable cells was calculated following a Prestoblue assay. Data are presented as mean ± SEM of three independent experiments. Note that the effect of the different doses of Carba1 alone on cell viability can be seen at the x-coordinate = 0, corresponding to 0 nM PTX. (D) Effect of Carba1 (12 μM), PTX (1 nM), and the combination of Carba1 and PTX (12 μM/1 nM) on HeLa cell apoptosis. HeLa cells, treated with the indicated concentrations of drugs, were stained with propidium iodide and annexin V and analyzed by flow cytometry. Results are expressed as mean ± SEM of three separate experiments. The significance was determined by a Student’s t-test (*** p < 0.001, compared to the control).