Via their cognate receptors, chemokines orchestrate the migration and activation of various classes of immune cells and, thus, play a central role in the pathogenesis of cellular inflammation that underlies a host of common diseases such as atherosclerosis, Alzheimer's disease, various forms of inflammatory lung disease and numerous cancers. As a consequence, there is intense interest in clarifying the roles of various chemokines and their receptors in human diseases and in the development of novel therapeutics and imaging approaches directed at this system. Currently, it is unclear whether broad spectrum or individually targeted therapeutics should be employed. Consequently, it is also uncertain whether imaging a panel of key chemokine receptors or targeting a specific receptor would be most useful as a diagnostic agent to determine disease activity, progression or assess drug treatment efficiency. However, what is clear is that the chemokine receptor imaging agents are underdeveloped. Given the constant evolution in human disease pathogenesis, it is critical the imaging methods that are developed are widely applicable in humans. Building upon our expertise in synthesizing various chemokine receptor targeted PET radiotracers for vascular injury, atherosclerosis and cancer applications, our objective is to first translate a broad spectrum chemokine receptor imaging agent using viral inflammatory macrophage protein-II (vMIP-II) to determine the overall expression of chemokine receptors in head and neck cancer patients and then focus a chemokine CC receptor 2 (CCR2) targeted PET radiotracer using a peptide ECL1 inverso (ECL1i). Information from these studies will guide further radiotracer optimization and assess potential for human imaing. To achieve this objective, we will pursue the following Specific Aims:
Aim 1. Translate the broad spectrum chemokine receptor PET radiotracer [64Cu]DOTA-vMIP-II for human imaging. We have developed a [64Cu]DOTA-vMIP-II peptide-based radiotracer to detect numerous chemokine receptors and have demonstrated its potential in multiple animal disease models and ex-vivo human tissue.
In Aim 1 A, we will optimize our radiotracer cell binding assay to screen potentially alternative radiotracer candidates and in parallel, evaluate radiotracer performance by one of our Collaborative Projects (CPs) in a non-human primate model of disease. If successful, we will then perform the necessary tasks to obtain approval for an Exploratory Investigational New Drug Application from the US Food and Drug Administration (Aim 1B).
In Aim 1 C we will perform a first-in-man evaluation of [64Cu]DOTA-vMIP-II in head and neck cancer patients to: 1) Assess its safety, biodistribution and radiation dosimetry and; 2) To evaluate its ability to detect chemokine receptor expression.
Aim 2. Translate the CCR2 targeted radiotracer [64Cu]DOTA-ECL1i for human imaging. We have prepared a [64Cu]DOTA-ECL1i peptide tracer for specific detection of CCR2 receptor and demonstrated imaging sensitivity and specificity in multiple pre-clinical models of disease and ex-vivo human tissue.
In Aim 1 A we optimize our radiotracer cell binding assay and our CPs will perform further in vivo assessment of [64Cu]DOTA-ECL1i in preclinical animal models relevant to human imaging to further guide radiotracer evaluation and development.
In Aims 2 B and 2C we will perform similar tasks as described in Aims 1B and 1C to complete a first-in-man study in head and cancer patients to evaluate the safety/ biodistribution and performance characteristics of this radiotracer. Ultimately, these tools would help acquire new knowledge on the role of chemokine biology in human disease pathogenesis, laying the foundation for new diagnostic and treatment paradigms and ultimately, improved human health.
