Enhanced imaging and treatment of aggressive subtypes of prostate cancer

Targeting the prostate-specific membrane antigen (PSMA) with small molecules for imaging and therapy of prostate cancer (PC) has revitalized the field of nuclear medicine. Few targets have its combination of salutary attributes, namely, high concentration in malignant with restricted expression in normal tissues, easy access with

recycling to and from the plasma membrane, an enzymatic active site toward which small molecules of high affinity and specificity can be designed, and biological relevance – an inverse relationship with androgen signaling while being directly related to degree of malignancy. The ureas that we initially described for imaging

PSMA in 2002 have inspired a wide variety of cancer targeting species from radiotherapeutics to synthetic antibody mimics. Our goal is to use what we have learned from PSMA-targeted detection, imaging and treatment of PC to focus on highly aggressive disease, including that which does not express PSMA. We will deploy this

prolific cancer target here by beginning with a project that leverages the considerable clinical data obtained during the last funding period to refine and simplify PSMA-targeted imaging with positron emission tomography (PET) – in a way agnostic to imaging agent employed. Complementing PET we will explore sensitive new PSMA-

targeted agents and methods for photoacoustic (PA) imaging, which can characterize primary disease in new ways in an effort to uncover signatures that could separate aggressive from indolent cancer to prevent unnecessary surgery and its attendant morbidity. Because PC is a heterogeneous disease, in the second half of

the project we will move from detection and characterization of PSMA-expressing PC to address highly aggressive, PSMA-negative adenocarcinoma and especially neuroendocrine PC (NEPC), a lethal and increasingly prevalent subtype with the proliferation of modern anti-androgen therapies. First, we will use a

PSMA reporter gene strategy to track NEPC-targeted chimeric antigen receptor (CAR) T cells in order to gauge their spatial relationship to tumor, measure their expansion in vivo, and sense their microenvironment, with a view to improving this case of solid tumor CAR T cell therapy. Finally, we will use cancer cell specific promoter

(CCSP) technology, which we developed for imaging and treating metastases, to enhance PSMA expression specifically within NEPC tissue so that it may become susceptible to the detection and treatment of its PSMA- expressing adenocarcinoma counterpart. In addition to using existing PSMA-targeted radiotherapy we will show

how a new urea-drug conjugate we have developed can kill NEPC once it is re-programmed to express PSMA. To achieve these goals, we take the approach of beginning with a more sophisticated analysis of our clinical PSMA PET data then work toward more laboratory-based imaging and therapeutic studies also designed for

translation. The team we have assembled is comprised of clinicians and scientists with a track record of high productivity and impact working together.