PS-1145, an IKK inhibitor, showed up today in Clinical Cancer Research, showing promise for certain lymphomas. Anybody know what's happened to it?
>>Clinical Cancer Research Vol. 11, 28-40, January 2005
Small Molecule Inhibitors of IB Kinase Are Selectively Toxic for Subgroups of Diffuse Large B-Cell Lymphoma Defined by Gene Expression Profiling
Lloyd T. Lam1, R. Eric Davis1, Jackie Pierce2, Michael Hepperle2, Yajun Xu2, Maria Hottelet2, Yuhua Nong2, Danyi Wen2, Julian Adams2, Lenny Dang2 and Louis M. Staudt1
1 Metabolism Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland and 2 Millennium Pharmaceuticals, Cambridge, Massachusetts
Requests for reprints: Louis M. Staudt, 9000 Rockville Pike, Building 10, Room 5A/02, Bethesda, MD 20892. Phone: 301-402-1892; Fax: 301-496-9956; E-mail: lstaudt@mail.nih.gov.
Constitutive activation of the NF-B pathway is required for survival of the activated B cell–like (ABC) subgroup of diffuse large B-cell lymphoma (DLBCL). Here we show that a small molecule IB kinase (IKK) inhibitor, PS-1145, and related compounds are toxic for ABC DLBCL cell lines but not for cell lines derived from the other prevalent form of DLBCL, germinal center B cell–like DLBCL. Treatment of ABC lines with these inhibitors rapidly induced a series of gene expression changes that were attributable to cessation of constitutive IKK activity, similar to changes induced by acute expression of genetic inhibitors of NF-B, confirming the effectiveness and specificity of this compound. Before cell death, inhibition of IKK also induced features of apoptosis and an arrest in the G1 phase of the cell cycle. To test further the specificity of this toxicity, an inducible form of NF-B was created by fusing the p65 NF-B subunit with the ligand-binding domain of the estrogen receptor (p65-ERD). In the presence of tamoxifen, p65-ERD reversed the toxicity of IKK inhibition and restored expression of many NF-B target genes. Another subgroup of DLBCL, primary mediastinal B-cell lymphoma (PMBL), also expresses NF-B target genes, and treatment of a PMBL cell line with an IKK inhibitor was toxic and induced gene expression changes of a distinct group of NF-B target genes. These studies validate the NF-B pathway as a promising therapeutic target in ABC DLBCL, PMBL, and other lymphomas that depend on the activity of NF-B for survival and proliferation. <<
TIA & Cheers, Tuck |
