Cell experiment:

5TMM cells (0.5 × 106/mL) were pretreated with different concentrations of Talmapimod (SCIO-469) in serum-free medium and then placed in the lower compartment of a Transwell system. Syngeneic bone marrow stromal cells were seeded into the Transwell itself. After 18 h, the 5TMM cells were collected from the lower compartment and stained for active caspase-3 with a FITC-labeled antibody according to manufacturer's instructions

Animal experiment:

Animal injection[1]For studies of the effect of Talmapimod (SCIO-469) on myeloma development, three groups of male mice (n = 12) were injected i.v. with 0.5 × 106 5T33MM cells. Mice were left untreated (naive) or, if injected with tumor cells, treated from the time of tumor cells injection with either Talmapimod (SCIO-469) (150 or 450 mg/kg powder diet continuously available for the mice) or a vehicle (PBS) until the first mice showed signs of morbidity (at 3.7 weeks).

Talmapimod (SCIO-469) is a selective ATP-competitive p38 inhibitor with IC50 of 9 nM for p38α.

Talmapimod (SCIO-469)decreased constitutive p38α MAPK phosphorylation of both 5T2MM and 5T33MM cells. Talmapimod (SCIO-469) also inhibits secretion and expression of the osteoclast-activating factors IL-11, receptor activator of NF-κB ligand, and macrophage inflammatory protein 1α, and prevents human osteoclast activationIn. It can also inhibit multiple myeloma growth and prevents bone disease in the 5T2MM and 5T33MM models.

Targeting p38α MAPK with Talmapimod (SCIO-469) decreases myeloma burden in addition to preventing the development of myeloma bone disease.

[1]. Hideshima T et al. p38 MAPK inhibition enhances PS-341 (bortezomib)-induced cytotoxicity against multiple myeloma cells. Oncogene. 2004 Nov 18, 23(54), 8766-76. [2]. Vanderkerken K et al. Inhibition of p38alpha mitogen-activated protein kinase prevents the development of osteolytic bone disease,reduces tumor burden, and increases survival in murine models of multiple myeloma. Vanderkerken K et al.