Molecules containing lysine-ureido-glutamate functional groups bind to the active site of prostate specific membrane antigen, which is overexpressed in prostate cancer. To prepare copper radiopharmaceuticals for the diagnosis and therapyofprostate cancer,macrobicyclic sarcophagine ligands tethered to either one or two lysine-ureido-glutamate functional groups through an appropriate linker have been prepared. Sarcophagine ligands can be readily radiolabeled with positron-emitting copper-64 at room temperature.T he bivalent agent, in which two targeting groups are tethered to as ingle copper complex, dramatically outperforms the monomeric agent with respect to tumor uptake and retention. The high tumor uptake,l ow background, and prolonged tumor retention, even at 24 hours post injection, suggest the bivalent agent is apromising diagnostic for prostate cancer and could be used for prospective dosimetry for therapywith acopper-67 variant.

Developing new therapies for stroke is urgently needed, as this disease is the leading cause of death and disability worldwide, and the existing treatment is only available for a small subset of patients. The interruption of blood flow to the brain during ischemic stroke launches multiple immune responses, characterized by infiltration of peripheral immune cells, the activation of brain microglial cells, and the accumulation of immune mediators. Copper is an essential trace element that is required for many critical processes in the brain. Copper homeostasis is disturbed in chronic neurodegenerative diseases and altered in stroke patients, and targeted copper delivery has been shown to be protective against chronic neurodegeneration. This study was undertaken to assess whether the copper bis(thiosemicarbazone) complex, Cu(atsm), is beneficial in acute brain injury, in preclinical mouse models of ischemic stroke. We demonstrate that the copper complex Cu(atsm) protects neurons from excitotoxicity and N2a cells from OGD in vitro, and is protective in permanent and transient ischemia models in mice as measured by functional outcome and lesion size. Copper delivery in the ischemic brains modulates the inflammatory response, specifically affecting the myeloid cells. It reduces CD45 and Iba1 immunoreactivity, and alters the morphology of Iba1 positive cells in the ischemic brain. Cu(atsm) also protects endogenous microglia against ischemic insult and reduces the proportion of invading monocytes. These results demonstrate that the copper complex Cu(atsm) is an inflammation-modulating compound with high therapeutic potential in stroke and is a strong candidate for the development of therapies for acute brain injury.

Amyloid-β plaques, consisting of aggregated amyloid-β peptides, are one of the pathological hallmarks of Alzheimer's disease. Copper complexes formed using positron-emitting copper radionuclides that cross the blood−brain barrier and bind to specific molecular targets offer the possibility of noninvasive diagnostic imaging using positron emission tomography. New thiosemicarbazone-pyridylhydrazone based ligands that incorporate pyridyl-benzofuran functional groups designed to bind amyloid-β plaques have been synthesized. The ligands form stable complexes with copper(II) (K d = 10 −18 M) and can be radiolabeled with copper-64 at room temperature. Subtle changes to the periphery of the ligand backbone alter the metabolic stability of the complexes in mouse and human liver microsomes, and influenced the ability of the complexes to cross the blood−brain barrier in mice. A lead complex was selected based on possessing the best metabolic stability and brain uptake in mice. Synthesis of this lead complex with isotopically enriched copper-65 allowed us to show that the complex bound to amyloid-β plaques present in post-mortem human brain tissue using laser ablation-inductively coupled plasma-mass spectrometry. This work provides insight into strategies to target metal complexes to amyloid-β plaques, and how small modifications to ligands can dramatically alter the metabolic stability of metal complexes as well as their ability to cross the blood−brain barrier.

Background: Neuroinflammation and biometal dyshomeostasis are key pathological features of several neurodegenerative diseases, including Alzheimer’s disease (AD). Inflammation and biometals are linked at the molecular level through regulation of metal buffering proteins such as the metallothioneins. Even though the molecular connections between metals and inflammation have been demonstrated, little information exists on the effect of copper modulation on brain inflammation.Methods: We demonstrate the immunomodulatory potential of the copper bis(thiosemicarbazone) complex CuII(atsm) in an neuroinflammatory model in vivo and describe its anti-inflammatory effects on microglia and astrocytes in vitro.Results: By using a sophisticated in vivo magnetic resonance imaging (MRI) approach, we report the efficacy of CuII(atsm) in reducing acute cerebrovascular inflammation caused by peripheral administration of bacterial lipopolysaccharide (LPS). CuII(atsm) also induced anti-inflammatory outcomes in primary microglia [significant reductions in nitric oxide (NO), monocyte chemoattractant protein 1 (MCP-1), and tumor necrosis factor (TNF)] and astrocytes [significantly reduced NO, MCP-1, and interleukin 6 (IL-6)] in vitro. These anti-inflammatory actions were associated with increased cellular copper levels and increased the neuroprotective protein metallothionein-1 (MT1) in microglia and astrocytes.Conclusion: The beneficial effects of CuII(atsm) on the neuroimmune system suggest copper complexes are potential therapeutics for the treatment of neuroinflammatory conditions.

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