Cell experiment:

The inhibitory effect of PS-1145 on MM growth is assessed by measuring MTT dye absorbance of the cells. MM.1S cells are cultured for 48 h with 0.2 and 1 ng/mL TNFα, in the absence or presence of 2.5 μM, 5 μM, and 10 μM PS-1145. Cell viability is assessed by MTT assay. Cells from 48 h cultures are pulsed with 10 μL of 5 mg/mL MTT to each well for the last 4 h of 48-h cultures, followed by 100 μL of isopropanol containing 0.04N HCl. Absorbance is measured at 570 nm using a spectrophotometer[1].

Animal experiment:

Mice[2]C57BL/6 (B6), B10.BR, and B6.SJL mice are used. Mice receive regular mouse chow and acidified tap water ad libitum. Bortezomib is administered intravenously to animals at a dose of 1 mg/kg, whereas PS-1145 is given intraperitoneally at a dose of 50 mg/kg. The first dose of each agent is administered before conditioning with total body irradiation (TBI).Rats[3]Weight-matched male Wistar rats (320-350 g) are used. Four groups of rats (n=6/group) consume the HFD for a 9-day study period. Animals in each group receive two consecutive icv injections three times/wk. Immediately prior to icv injection of IL-4 (100 ng) or vehicle, all animals receive a pretreatment icv injection of either the IKKβ inhibitor PS1145 (10 μg) or its vehicle (saline). Food intake and body weight are measured daily. Body composition analysis is conducted as above on days 0 and 8. On day 9, animals are euthanized and samples collected.

IC50: 88 nM

PS-1145 is an IkappaB kinase (IKK) inhibitor.

The IκB kinase is an enzyme complex involved in propagating the cellular response to inflammation. This enzyme complex is reported to be part of the upstream NF-κB signal transduction cascade.

In vitro: Previous study found that PS-1145 could block TNFalpha-induced NF-kappaB activation in a dose- and time-dependent manner in MM cells, which up-regulated IkappaBalpha protein, enhanced blockade of NF-kappaB activation. In addition, PS-1145 blocked the protective effect of IL-6 against Dex-induced apotosis and TNFalpha-induced ICAM-1 expression was also inhibited by PS-1145. Moreover, PS-1145 inhibited both IL-6 secretion from BMSCs triggered by MM cell adhesion and proliferation of MM cells adherent to BMSCs. However, PS-1145 could only partially inhibit MM cell proliferation. Importantly, it was found that TNFalpha induced MM cell toxicity in the presence of PS-1145 [1]

In vivo: Animal study showed that the intravenous application of PS-1145 could promote direct apoptosis in DMBA-induced skin tumor in male Wistar rats via blocking NF-κB and VEGF activities [2].

Clinical trial: Up to now, PS-1145 is still in the preclinical development stage.

References:
[1] Hideshima T,Chauhan D,Richardson P,Mitsiades C,Mitsiades N,Hayashi T,Munshi N,Dang L,Castro A,Palombella V,Adams J,Anderson KC.  NF-kappa B as a therapeutic target in multiple myeloma. J Biol Chem.2002 May 10;277(19):16639-47.
[2] Rajmani RS,Gandham RK,Gupta SK,et al.  Administration of IκB-kinase inhibitor PS1145 enhances apoptosis in DMBA-induced tumor in male Wistar rats. Cell Biol Int.2015 Nov;39(11):1317-28.