Characterization of Alisertib (MLN8237), an investigational small-molecule inhibitor of aurora A kinase using novel in vivo pharmacodynamic assays.
OBJECTIVE
Small-molecule inhibitors of Aurora A (AAK) and B (ABK) kinases, which play important roles in mitosis, are currently being pursued in oncology clinical trials. We developed three novel assays to quantitatively measure biomarkers of AAK inhibition in vivo. Here, we describe preclinical characterization of alisertib (MLN8237), a selective AAK inhibitor, incorporating these novel pharmacodynamic assays.


METHODS
We investigated the selectivity of alisertib for AAK and ABK and studied the antitumor and antiproliferative activity of alisertib in vitro and in vivo. Novel assays were used to assess chromosome alignment and mitotic spindle bipolarity in human tumor xenografts using immunofluorescent detection of DNA and alpha-tubulin, respectively. In addition, 18F-3'-fluoro-3'-deoxy-l-thymidine positron emission tomography (FLT-PET) was used to noninvasively measure effects of alisertib on in vivo tumor cell proliferation.


RESULTS
Alisertib inhibited AAK over ABK with a selectivity of more than 200-fold in cells and produced a dose-dependent decrease in bipolar and aligned chromosomes in the HCT-116 xenograft model, a phenotype consistent with AAK inhibition. Alisertib inhibited proliferation of human tumor cell lines in vitro and produced tumor growth inhibition in solid tumor xenograft models and regressions in in vivo lymphoma models. In addition, a dose of alisertib that caused tumor stasis, as measured by volume, resulted in a decrease in FLT uptake, suggesting that noninvasive imaging could provide value over traditional measurements of response.


CONCLUSIONS
Alisertib is a selective and potent inhibitor of AAK. The novel methods of measuring Aurora A pathway inhibition and application of tumor imaging described here may be valuable for clinical evaluation of small-molecule inhibitors.
Millennium Pharmaceuticals, Inc., Cambridge, 40 Landsdowne Street, Cambridge, MA 02139, USA. mark.manfredi@mpi.com
Mark G
MG
Manfredi
Jeffrey A
JA
Ecsedy
Arijit
A
Chakravarty
Lee
L
Silverman
Mengkun
M
Zhang
Kara M
KM
Hoar
Stephen G
SG
Stroud
Wei
W
Chen
Vaishali
V
Shinde
Jessica J
JJ
Huck
Deborah R
DR
Wysong
David A
DA
Janowick
Marc L
ML
Hyer
Patrick J
PJ
Leroy
Rachel E
RE
Gershman
Matthew D
MD
Silva
Melissa S
MS
Germanos
Joseph B
JB
Bolen
Christopher F
CF
Claiborne
Todd B
TB
Sells
D000818:Animals; D064096:Aurora Kinase A; D064127:Aurora Kinases; D001381:Azepines / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D015224:Dideoxynucleosides / Q000493:pharmacokinetics; D005260:Female; D005462:Fluorine Radioisotopes; D045325:HCT116 Cells; D006367:HeLa Cells; D006801:Humans; D008223:Lymphoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D016513:Mice, SCID; D008940:Mitotic Index; D015394:Molecular Structure; D009369:Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation / Q000187:drug effects; D049268:Positron-Emission Tomography; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011743:Pyrimidines / Q000737:chemistry / Q000494:pharmacology*; D008941:Spindle Apparatus / Q000187:drug effects* / Q000378:metabolism; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
D001381:Azepines; D015224:Dideoxynucleosides; D005462:Fluorine Radioisotopes; C550258:MLN 8237; D011743:Pyrimidines; C576918:Aurka protein, mouse; D064096:Aurora Kinase A; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases; C002854:alovudine