Figure 4From: FL118, a novel camptothecin derivative, is insensitive to ABCG2 expression and shows improved efficacy in comparison with irinotecan in colon and lung cancer models with ABCG2-induced resistanceElectronegative potentials influence the affinity of the Position 7-substituted FL118 analogues for ABCG2 binding. A, structures of FL118 analogues with B ring substitutions. B, correlation between electronegativity of chemical groups (χ, Pauling units, calculated using the method of Huheey) and the ratio of EC50 of drug alone / EC50 drug + Ko143.Back to article page