huJ591

Prostate-specific membrane antigen (PSMA)-targeted PET has shown strong potential for localizing metastatic prostate cancer, as we have shown with [⁸⁹Zr]Zr-huJ591 immuno-PET.Here, we report the case of a 51-yr-old woman diagnosed 8.5 years ago with grade II oligodendroglioma (1p/19q co-deleted, IDH mutant) who was referred for [⁸⁹Zr]Zr-huJ591 PET two days after MRI performed with i.v. injected gadopentetate dimeglumine (Magnevist; Bayer HealthCare Pharmaceuticals, Wayne, NJ) revealed concern for disease progression despite multiple prior treatments including surgery and chemoradiation, most recently with IDH inhibitor AG-120 (NCT02074839).[⁸⁹Zr]Zr-huJ591 PET offers quant. visualization of PSMA expression in neovasculature, prospective dosimetry for huJ591-based radioimmunotherapy supported by serial imaging over multiple days, and assessment of response to radiolabeled J591 and other anti-angiogenic agents.Cold antibody huJ591 (23.5 mg) was injected i.v. over five minutes followed by 182.04 MBq/1.5 mg of [⁸⁹Zr]Zr-huJ591 injected i.v. over one minute.In view of the persistent and/or continuously rising lesional tracer accumulation in this patient, longer post-injection imaging periods are indicated in future studies, particularly for optimized dosimetric calculations

Statins are cholesterol-depleting drugs used to treat patients with hypercholesterolemia. Preclinically, statins disrupt trafficking of receptors present at the cell membrane. Membrane receptors, defined as tumor biomarkers and therapeutic targets, are often internalized by an endocytic pathway. Indeed, receptor endocytosis and recycling are dynamic mechanisms that often affect receptor density at the cell surface. In therapies using monoclonal antibodies (mAb), a downregulation in receptor density at the cell surface decreases antibody binding to the extracellular domain of the membrane receptor. Here, we determined the potential of lovastatin, simvastatin, and rosuvastatin in preclinically modulating epidermal growth factor receptor (EGFR) and prostate-specific membrane antigen (PSMA) receptor density at the tumor cell surface.

Small-animal PET was used to study the binding of 89Zr-labeled antibodies in ectopic xenografts. Ex vivo analyses were performed to determine changes in endocytic proteins, EGFR, and PSMA surface levels.

Acute statin treatment using lovastatin, simvastatin, or rosuvastatin enhanced tumors' avidity for the mAbs panitumumab, cetuximab, and huJ591. Statins temporarily modulated caveolin-1, cavin-1, endophilin, clathrin, and dynamin proteins in EGFR- and PSMA-overexpressing xenografts.

These data show the potential of statins as pharmacologic modulators of endocytic proteins for improved tumors' accumulation of mAbs. The translational significance of these findings lies in the potential of statins to temporarily modulate the heterogeneous presence of receptors at the cell membrane, a characteristic often associated with poor response in tumors to therapeutic antibodies.