Biomarkers that indicate
biological activity and/or efficacy are a potentially useful tool in the development of molecularly targeted
therapeutics. It is useful, though challenging, to identify
biomarkers during preclinical development in order to impact decision-making during early clinical development.
SU11248 is an oral, selective multitargeted
tyrosine kinase inhibitor currently in Phase II oncology clinical trials. It exhibits direct antitumor and antiangiogenic activity via inhibition of the
receptor tyrosine kinases PDGFR, VEGFR, KIT and FLT3. To identify clinically translatable
biomarkers of
SU11248 activity, expression profiling was performed on Colo205 human xenograft
tumors following treatment with
SU11248. Over 100 transcripts changed in abundance in
SU11248 as compared to vehicle-treated
tumors. Nine candidate transcripts, chosen based on putative function, were also analysed and validated by TaqMan. One such potential
biomarker,
cadherin-11, was further evaluated at the
protein level and was found to have increased expression in xenograft
tumors after
SU11248 treatment. Interestingly,
cadherin-11 expression was also detected via immunohistochemical analysis of archived solid
tumors, indicating the technical feasibility of translating this putative
biomarker to clinical studies. Importantly,
SU11248 treatment also resulted in increased expression of
cadherin-11 protein in human
tumor biopsies in three out of seven patients examined and confirms the feasibility of using transcriptional profiling of preclinical models to identify clinically translatable
biomarkers.