Figure 2.

Influence of trans-4-methylcyclohexylamine (MCHA), N-cyclohexyl-1,3-propanediamine (CDAP), polyamine transport inhibitor (PTI, trimer 44), and difluoromethylornithine (DFMO) on L3.6pl human pancreatic cancer cell growth. Panel A: Growth inhibition by MCHA, CDAP, and the trimer44 PTI in L3.6pl cells after 72 h incubation at 37 °C in a 5% CO₂ atmosphere. The 72 h IC₅₀ values of MCHA, CDAP, and trimer44 PTI in L3.6pl human pancreatic cancer cells were 1000 ± 4.4 µM, 941 ± 12.1 µM, and 69.6 ± 1.8 µM, respectively. In general, the PTI was well tolerated at low doses (e.g., 4 µM with no reduction in growth) and the other inhibitors could be dosed at high concentrations with little effect on cell growth. For example, after 72 h, MCHA and CDAP at 100 µM gave 91% and 99% relative growth, respectively, versus the untreated control. Panel B: Relative cell growth in the presence of DFMO in L3.6pl cells after 72 h incubation at 37 °C in a 5% CO₂ atmosphere. The 72 h IC₅₀ value of DFMO in L3.6pl cells was 4.24 ± 0.11 mM.