Thermal sensitisation by lonidamine of human melanoma cells grown at low extracellular pH

Figures & data

Table I. Summary of the effects of 150 μM LND on pH_i in DB-1 cells.

Treatment pHe	Control	150 μM lonidamine
7.3	7.20 ± 0.07 (6)	7.15 ± 0.16 (3)
7.3–7.1	7.05 ± 0.04 (3)	6.93 ± 0.15 (4)
6.7	6.76 ± 0.04 (5)	6.30 ± 0.21 (9)
6.7–6.5	6.52 ± 0.15 (7)	6.09 ± 0.26 (6)

The pH_i values (mean ± SD) are after 60 min at 37 °C. Extracellular pH (pH_e) was measured immediately following the 60 min of pH_i monitoring. The number of separate experiments is in parentheses.

Figure 1. Abrogation of induction of HSP70 (A) and HSP27 (B) during heating by 150 μM LND. Cells grown at pH_e 7.3 and pH_e 6.7 were exposed to LND for 60 min prior to and during heating (42 °C, 2 h) without or with a 0.2-pH unit acute acidification. Flasks of cells were processed for immunoblot studies before treatments and immediately after the 2 h of heating. HSP levels are presented as percent of HSP levels in unheated cells at their growth pH_e. The means (bars) and standard errors represent results from two different experiments. 37 °C (white); LND, 37 °C (stippled); 42 °C (gray); LND + 42 °C (black).

Figure 2. Enhancement of cell killing by exposure of DB-1 cells to 150 μM LND prior to and during heating (42 °C, 2 h). Cells grown at pH_e 7.3 and pH_e 6.7 were exposed to LND for 60 min prior to and during heating (42 °C, 2 h) without or with a 0.2-pH unit acute acidification. The means (bars) and standard errors represent results from two different experiments. 37 °C (white); LND, 37 °C (stippled); 42 °C (gray); LND + 42 °C (black).