TPCA-1

In a time-resolved fluorescence resonance energy transfer assay, TPCA-1 inhibits human IKK-2 activity with an IC50 of 17.9 nM. In addition, TPCA-1 is demonstrated to be ATP-competitive. Besides, TPCA-1 exhibits IC50 values of 400 nM and 3600 nM against IKK-1 and JNK3, respectively. TPCA-1 inhibits the production of TNF-α, IL-6, and IL-8 in a concentration-dependent manner, exhibiting IC50 values of 170, 290, and 320 nM, respectively. ^[1] TPCA-1 inhibits glioma cell proliferation, as well as TNF-induced RelA (p65) nuclear translocation and NFκB-dependent IL8 gene expression. Importantly, TPCA-1 inhibits IFN-induced gene expression, completely suppressing MX1 and GBP1 gene expression, while having only a minor effect on ISG15 expression. ^[2]

Prophylactic administration of TPCA-1 at 3, 10, or 20 mg/kg, i.p., b.i.d., results in a dose-dependent reduction in the severity of murine collagen-induced arthritis (CIA). The significantly reduced disease severity and delay of disease onset resulting from administration of TPCA-1 at 10 mg/kg, i.p., b.i.d. are comparable to the effects of the antirheumatic drug, etanercept, when administered prophylactically at 4 mg/kg, i.p., every other day. Nuclear localization of p65, as well as levels of IL-1beta, IL-6, TNF-alpha, and interferon-gamma, is significantly reduced in the paw tissue of TPCA-1- and etanercept-treated mice. In addition, administration of TPCA-1 in vivo results in significantly decreased collagen-induced T cell proliferation ex vivo. Therapeutic administration of TPCA-1 at 20 mg/kg, but not at 3 or 10 mg/kg, i.p., b.i.d., significantly reduces the severity of CIA, as does etanercept administration at 12.5 mg/kg, i.p., every other day. ^[1]