N2733, 1-[3-(3-pyridyl)-acryloyl]-2-pyrrolidinone hydrochloride inhibits LPS-induced TNF-alpha production and improves survival in endotoxemic mice

N2733, 1-[3-(3-pyridyl)-acryloyl]-2-pyrrolidinone hydrochloride, was examined for its effect on TNF-alpha production by human myeloid THP-1 cells stimulated with lipopolysaccharide (LPS). N2733 inhibited LPS-induced release of TNF-alpha from THP-1 cells with an IC50 of 11 microM. N2733 did not affect the cell viability at the concentration of 50 microM or 100 microM. This indicates that N2733 is a potent inhibitor for TNF-alpha production without severe cytotoxicity. N2733 was also studied in two murine endotoxin shock models induced with LPS. One model was DBA/2 mice injected with LPS (5.6 mg/kg, i.v.), which increased the serum level of TNF-alpha within 1 hr. Treatment of these mice with N2733 (100 mg/kg x 2, i.p.) decreased the serum level of TNF-alpha significantly. Another model was DBA/2 mice induced with LPS (30 mg/kg, i.v.), which reduced the survival rate to 30% during 7 days. Administrations of 30 mg/kg and 100 mg/kg N2733 (i.v.) restored the survival rates to 60% and 90% respectively. Our data demonstrate that N2733 inhibits LPS-induced TNF-alpha production, and this response is associated with an improvement in the survival rate of endotoxemic mice.

Effect of newly synthesized indole derivatives on multidrug resistance in human cancer cells

Twenty indole derivatives were investigated for their ability to reverse multidrug resistance (MDR), for their ability to compete with [3H]azidopine in binding to P-glycoprotein (P-gp) and for their hydrophobicity. Six derivatives almost completely reversed the resistance to vincristine (VCR) in multidrug-resistant KB-C2 cells, and other derivatives partially overcame the resistance. The ability of the derivatives to enhance vincristine cytotoxicity did not significantly correlate with the inhibition of [3H]azidopine binding to P-gp or with their hydrophobicity. However, all the derivatives that inhibited > 50% of the photolabeling completely reversed VCR resistance. The 2-pyridyl group with a basic nitrogen atom attached at position 3 of indole in an appropriate spatial orientation seems to be an important feature for the interaction of the indole derivatives with P-gp. One of the derivatives, 1, which has low cytotoxicity and hydrophobicity, completely reversed the resistance of KB-C2 cells to Adriamycin, actinomycin D and VCR. Our data indicate that MDR-reversing indole derivatives with low cytotoxicity and hydrophobicity exist. These characteristics will surely be profitable for clinical use.