Figure 2

HA-CD44 interactions mediate chemoresistance in ovarian cancer cells. A. HA oligomers (HYA oligo, 250 μg/ml) and anti-rat neutralizing CD44 monoclonal antibody (20 μg/ml) blocked increased survival of OVCAR-5 and OV-90 cells treated with HA (5 μg/ml) and carboplatin (CBP, LD₅₀ dose), but had no effect on OVCAR-3 cells. B. HYA oligo increased the sensitivity of SKOV-3 cells to CBP. SKOV-3 cells were treated with CBP (0–200 μM) ± HYA oligo (250 μg/ml) for 72 hr. The CBP LD₅₀ calculated using exponential curve fitting was 173 μM in the presence of CBP alone and reduced to 123 μM when CBP was combined with HYA oligo. Data are expressed as percentage of control, mean ± SD from 2 independent experiments performed in triplicate. *, significantly different from control (P < 0.05, independent t test).