TP-3654, a second-generation Pim kinase inhibitor (Ki values against Pim-1/3: 5/42 nM).

Pim2:239 nM (Ki), Pim1:5 nM (Ki), Pim3:42 nM (Ki)

TP-3654 exhibits strong specificity and activity against PIM-1 in systems overexpressing PIM-1/BAD, achieving an average EC50 of 67 nM. It effectively diminishes phospho-BAD levels in vitro within the UM-UC-3 bladder cancer cell line. Moreover, TP-3654 significantly hampers colony growth in both T24 and UM-UC3 cells, underscoring the reliance of these cell lines on PIM-1 for their proliferation [1].

TP-3654 (200 mg/kg, i.g.) significantly reduces both UM-UC-3 and PC-3 tumour growth measured by volume (calliper) and by final tumour weight, with no significant changes in body weight or gross adverse toxicity[1].

1 μM TP-3654 is tested against 336 kinases at a concentration of 10 μM ATP. IC50 determinations of phosphoinositide 3-kinase (PI3K) (α, β, δ, and γ) and all kinases inhibited by >50% from the initial screen are performed using 10-dose, three-fold serial dilutions of TP-3654 starting with 10 μM at Km ATP concentrations for each kinase[1].

When tumours of mice reach 100 to 200 mm3 by calliper measurement, mice are randomized and oral dosing of TP-3654 or vehicle control began and continued every day for 5 days with 2 days off for 18 to 21 days. Tumour volumes and body weights were determined twice a week[1].