TY - JOUR
T1 - AT7519, a cyclin-dependent kinase inhibitor, exerts its effects by transcriptional inhibition in leukemia cell lines and patient samples
AU - Squires, Matthew S.
AU - Cooke, Laurence
AU - Lock, Victoria
AU - Qi, Wenqing
AU - Lewis, E. Jonathan
AU - Thompson, Neil T.
AU - Lyons, John F.
AU - Mahadevan, Daruka
PY - 2010/4
Y1 - 2010/4
N2 - AT7519 is a potent inhibitor of several cyclin-dependent kinases and is currently in early phase clinical development. Recently, cyclin-dependent kinases 7, 8, and 9 have been shown to regulate transcription through phosphorylation of RNA polymerase II. B-cell lymphoproliferative disorders, including chronic lymphocytic leukemia, rely on the expression of transcripts with a short half-life, such as Mcl-1, Bcl-2, and XIAP, for survival. Here, we describe the characterization of AT7519 in leukemia cell lines, and compare and contrast the response in cell lines derived from solid tumors. Finally, we use these mechanistic insights to show activity in peripheral blood mononuclear cells isolated from 16 chronic lymphocytic leukemia patients. AT7519 induced apoptosis at concentrations of 100 to 700 nmol/L and was equally effective regardless of Rai stage or known prognostic markers. Short-term treatments (4-6 hours) resulted in inhibition of phosphorylation of the transcriptional marker RNA polymerase II and downregulation of the antiapoptotic protein Mcl-1, with no effect on either XIAP or Bcl-2 levels. The reduction in Mcl-1 protein level was associated with an increase in cleaved poly(ADP-ribose) polymerase. Together the data suggest AT7519 offers a promising treatment for patients with advanced B-cell leukemia.
AB - AT7519 is a potent inhibitor of several cyclin-dependent kinases and is currently in early phase clinical development. Recently, cyclin-dependent kinases 7, 8, and 9 have been shown to regulate transcription through phosphorylation of RNA polymerase II. B-cell lymphoproliferative disorders, including chronic lymphocytic leukemia, rely on the expression of transcripts with a short half-life, such as Mcl-1, Bcl-2, and XIAP, for survival. Here, we describe the characterization of AT7519 in leukemia cell lines, and compare and contrast the response in cell lines derived from solid tumors. Finally, we use these mechanistic insights to show activity in peripheral blood mononuclear cells isolated from 16 chronic lymphocytic leukemia patients. AT7519 induced apoptosis at concentrations of 100 to 700 nmol/L and was equally effective regardless of Rai stage or known prognostic markers. Short-term treatments (4-6 hours) resulted in inhibition of phosphorylation of the transcriptional marker RNA polymerase II and downregulation of the antiapoptotic protein Mcl-1, with no effect on either XIAP or Bcl-2 levels. The reduction in Mcl-1 protein level was associated with an increase in cleaved poly(ADP-ribose) polymerase. Together the data suggest AT7519 offers a promising treatment for patients with advanced B-cell leukemia.
UR - http://www.scopus.com/inward/record.url?scp=77950825064&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77950825064&partnerID=8YFLogxK
U2 - 10.1158/1535-7163.MCT-09-1071
DO - 10.1158/1535-7163.MCT-09-1071
M3 - Article
C2 - 20354122
AN - SCOPUS:77950825064
SN - 1535-7163
VL - 9
SP - 920
EP - 928
JO - Molecular cancer therapeutics
JF - Molecular cancer therapeutics
IS - 4
ER -