Robust in vivo MRI of OATP reporter gene expressing cells using standard clinical dose of MRI contrast agent

Hepatic OATPs are a promising molecular imaging reporter gene for MRI yet its translation for human studies is limited by the reported extremely high dose of contrast agent required (>40x clinical dose) for robust detection of engineered cells in vivo. Here we describe studies that culminated in the in vivo MRI detection of OATP-overexpressing cells using standard clinical doses. OATP-overexpression was accomplished by lentiviral transduction of tumor cells, followed by MRI screening to determine the best performing OATPs. In vivo MRI of OATP-overexpressing tumors was accomplished using a combination of both T1-weighted and dynamic contrast enhanced (DCE-) MRI.