Multidimensional biomarker predicts disease control in response to immunotherapy in recurrent or metastatic head and neck squamous-cell carcinoma.

PURPOSE: Anti-PD-1 therapy provides clinical benefit in 40-50% of patients with relapsed and/or metastatic head and neck squamous cell carcinoma (RM-HNSCC). Selection of anti- PD-1 therapy is typically based on patient PD-L1 immunohistochemistry (IHC) which has low specificity for predicting disease control. Therefore, there is a critical need for a clinical biomarker that will predict clinical benefit to anti-PD-1 treatment with high specificity. METHODS: Clinical treatment and outcomes data for 103 RM-HNSCC patients were paired with RNA-sequencing data from formalin-fixed patient samples. Using logistic regression methods, we developed a novel biomarker classifier based on expression patterns in the tumor immune microenvironment to predict disease control with monotherapy PD-1 inhibitors (pembrolizumab and nivolumab). The performance of the biomarker was internally validated using out-of-bag methods. RESULTS: The biomarker significantly predicted disease control (65% in predicted non-progressors vs. 17% in predicted progressors, p < 0.001) and was significantly correlated with overall survival (OS; p = 0.004). In addition, the biomarker outperformed PD-L1 IHC across numerous metrics including sensitivity (0.79 vs 0.64, respectively; p = 0.005) and specificity (0.70 vs 0.61, respectively; p = 0.009). CONCLUSION: This novel assay uses tumor immune microenvironment expression data to predict disease control and OS with high sensitivity and specificity in patients with RM-HNSCC treated with anti-PD-1 monotherapy.

Costs of Definitive Chemoradiation, Surgery, and Adjuvant Radiation Versus De-Escalated Adjuvant Radiation per MC1273 in HPV+ Cancer of the Oropharynx.

PURPOSE: De-escalated treatment for human papillomavirus (HPV)+ oropharynx squamous cell carcinoma (OPSCC) has shown promising initial results. Health-care policy is increasingly focusing on high-value care. This analysis compares the cost of care for HPV+ OPSCC treated with definitive chemoradiation (CRT), surgery and adjuvant radiation (RT), and surgery and de-escalated CRT on MC1273. METHODS AND MATERIALS: MC1273 is a prospective, phase 2 study evaluating adjuvant CRT to 30 to 36 Gy plus docetaxel for HPV+ OPSCC after surgery for high-risk patients. Matched standard-of-care control groups were retrospectively identified for patients treated with definitive CRT or adjuvant RT. Standardized costs were evaluated before radiation, during treatment (during RT), and at short-term (6 month) and long-term (7-24 month) follow-up periods. RESULTS: A total of 56 definitive CRT, 101 adjuvant RT, and 66 MC1273 patients were included. The CRT arm had more T3-4 disease (63% vs 17-21%) and higher N2c-N3 disease (52% vs 20-24%) vs both other groups. The total treatment costs in the CRT, adjuvant RT, and MC1273 groups were $47,763 (standard deviation [SD], $19,060], $57,845 (SD, $17,480), and $46,007 (SD, $9019), respectively, and the chemotherapy and/or RT costs were $39,936 (SD, $18,480), $26,603 (SD, $12,542), and $17,864 (SD, $3288), respectively. The per-patient, per-month, average short-term follow-up costs were $3860 (SD, $10,525), $1072 (SD, $996), and $972 (SD, $833), respectively, and the long-term costs were $978 (SD, $2294), $485 (SD, $1156), and $653 (SD, $1107), respectively. After adjustment for age, T-stage, and N-stage, treatment costs remained lower for CRT and MC1273 versus adjuvant RT ($45,450 and $47,114 vs $58,590, respectively; P < .001), whereas the total per-patient, per-month follow-up costs were lower in the MC1273 study group and adjuvant RT versus CRT ($853 and $866 vs $2030, respectively; P = .03). CONCLUSIONS: MC1273 resulted in 10% and 20% reductions in global costs compared with standard-of-care adjuvant RT and definitive CRT treatments. Substantial cost savings may be an added benefit to the already noted low toxicity and maintained quality of life of treatment per MC1273.

Intracellular distribution of fluorescent copper and zinc bis(thiosemicarbazonato) complexes measured with fluorescence lifetime spectroscopy.

The intracellular distribution of fluorescently labeled copper and zinc bis(thiosemicarbazonato) complexes was investigated in M17 neuroblastoma cells and primary cortical neurons with a view to providing insights into the neuroprotective activity of a copper bis(thiosemicarbazonato) complex known as Cu(II)(atsm). Time-resolved fluorescence measurements allowed the identification of the Cu(II) and Zn(II) complexes as well as the free ligand inside the cells by virtue of the distinct fluorescence lifetime of each species. Confocal fluorescent microscopy of cells treated with the fluorescent copper(II)bis(thiosemicarbazonato) complex revealed significant fluorescence associated with cytoplasmic puncta that were identified to be lysosomes in primary cortical neurons and both lipid droplets and lysosomes in M17 neuroblastoma cells. Fluorescence lifetime imaging microscopy confirmed that the fluorescence signal emanating from the lipid droplets could be attributed to the copper(II) complex but also that some degree of loss of the metal ion led to diffuse cytosolic fluorescence that could be attributed to the metal-free ligand. The accumulation of the copper(II) complex in lipid droplets could be relevant to the neuroprotective activity of Cu(II)(atsm) in models of amyotrophic lateral sclerosis and Parkinson's disease.

Altered synaptic structure in the hippocampus in a mouse model of Alzheimer's disease with soluble amyloid-ß oligomers and no plaque pathology.

BACKGROUND: Mounting evidence suggests that soluble oligomers of amyloid-ß (oAß) represent the pertinent synaptotoxic form of Aß in sporadic Alzheimer's disease (AD); however, the mechanistic links between oAß and synaptic degeneration remain elusive. Most in vivo experiments to date have been limited to examining the toxicity of oAß in mouse models that also possess insoluble fibrillar Aß (fAß), and data generated from these models can lead to ambiguous interpretations. Our goal in the present study was to examine the effects of soluble oAß on neuronal and synaptic structure in the amyloid precursor protein (APP) E693Q ("Dutch") mouse model of AD, which develops intraneuronal accumulation of soluble oAß with no detectable plaques in AD-relevant brain regions. We performed quantitative analyses of neuronal pathology, including dendrite morphology, spine density, and synapse ultrastructure in individual hippocampal CA1 neurons. RESULTS: When assessing neuronal morphology and complexity we observed significant alterations in apical but not in basal dendritic arbor length in Dutch mice compared to wild type. Moreover, Dutch mice exhibited a significant decrease in dendritic arborization with a decrease in dendritic length and number of intersections at 120 µm and 150 µm from the soma, respectively. We next examined synaptic parameters and found that while there were no differences in overall synaptic structure, Dutch mice displayed a significant reduction in the post-synaptic density (PSD) length of synapses on mushroom spines, in comparison to wild type littermates. CONCLUSION: The structural alterations to individual neurons in Dutch mice along with the changes in larger dendritic spines support the Aß oligomer hypothesis, which postulates that the early cognitive impairments that occur in AD are attributed to the accumulation of soluble oAß first affecting at the synaptic level with subsequent structural disturbances and cellular degeneration.

Oral treatment with Cu(II)(atsm) increases mutant SOD1 in vivo but protects motor neurons and improves the phenotype of a transgenic mouse model of amyotrophic lateral sclerosis.

Mutations in the metallo-protein Cu/Zn-superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS) in humans and an expression level-dependent phenotype in transgenic rodents. We show that oral treatment with the therapeutic agent diacetyl-bis(4-methylthiosemicarbazonato)copper(II) [Cu(II)(atsm)] increased the concentration of mutant SOD1 (SOD1G37R) in ALS model mice, but paradoxically improved locomotor function and survival of the mice. To determine why the mice with increased levels of mutant SOD1 had an improved phenotype, we analyzed tissues by mass spectrometry. These analyses revealed most SOD1 in the spinal cord tissue of the SOD1G37R mice was Cu deficient. Treating with Cu(II)(atsm) decreased the pool of Cu-deficient SOD1 and increased the pool of fully metallated (holo) SOD1. Tracking isotopically enriched (65)Cu(II)(atsm) confirmed the increase in holo-SOD1 involved transfer of Cu from Cu(II)(atsm) to SOD1, suggesting the improved locomotor function and survival of the Cu(II)(atsm)-treated SOD1G37R mice involved, at least in part, the ability of the compound to improve the Cu content of the mutant SOD1. This was supported by improved survival of SOD1G37R mice that expressed the human gene for the Cu uptake protein CTR1. Improving the metal content of mutant SOD1 in vivo with Cu(II)(atsm) did not decrease levels of misfolded SOD1. These outcomes indicate the metal content of SOD1 may be a greater determinant of the toxicity of the protein in mutant SOD1-associated forms of ALS than the mutations themselves. Improving the metal content of SOD1 therefore represents a valid therapeutic strategy for treating ALS caused by SOD1.

Adjusting the compass: new insights into the role of angiogenesis in Alzheimer's disease.

Growing evidence suggests that vascular perturbation plays a critical role in the pathogenesis of Alzheimer's disease (AD). It appears to be a common feature in addition to the classic pathological hallmarks of amyloid beta (Aß) plaques and neurofibrillary. Moreover, the accumulation of Aß in the cerebral vasculature is closely associated with cognitive decline, and disruption of the blood-brain barrier (BBB) has been shown to coincide with the onset of cognitive impairment. Although it was originally hypothesized that the accumulation of Aß and the subsequent disruption of the BBB were due to the impaired clearance of Aß from the brain, a body of data now suggests an alternative hypothesis for vascular dysfunction in AD that amyloidogenesis promotes extensive neoangiogenesis leading to increased vascular permeability and subsequent hypervascularization. In this review, we discuss the role Aß plays in angiogenesis of the neurovasculature and BBB and how it may contribute to the pathogenesis of AD. These studies suggest that interventions that directly or indirectly affect angiogenesis could have beneficial effects on amyloid and other pathways in AD.

C-Jun N-terminal kinase controls TDP-43 accumulation in stress granules induced by oxidative stress.

BACKGROUND: TDP-43 proteinopathies are characterized by loss of nuclear TDP-43 expression and formation of C-terminal TDP-43 fragmentation and accumulation in the cytoplasm. Recent studies have shown that TDP-43 can accumulate in RNA stress granules (SGs) in response to cell stresses and this could be associated with subsequent formation of TDP-43 ubiquinated protein aggregates. However, the initial mechanisms controlling endogenous TDP-43 accumulation in SGs during chronic disease are not understood. In this study we investigated the mechanism of TDP-43 processing and accumulation in SGs in SH-SY5Y neuronal-like cells exposed to chronic oxidative stress. Cell cultures were treated overnight with the mitochondrial inhibitor paraquat and examined for TDP-43 and SG processing. RESULTS: We found that mild stress induced by paraquat led to formation of TDP-43 and HuR-positive SGs, a proportion of which were ubiquitinated. The co-localization of TDP-43 with SGs could be fully prevented by inhibition of c-Jun N-terminal kinase (JNK). JNK inhibition did not prevent formation of HuR-positive SGs and did not prevent diffuse TDP-43 accumulation in the cytosol. In contrast, ERK or p38 inhibition prevented formation of both TDP-43 and HuR-positive SGs. JNK inhibition also inhibited TDP-43 SG localization in cells acutely treated with sodium arsenite and reduced the number of aggregates per cell in cultures transfected with C-terminal TDP-43 162-414 and 219-414 constructs. CONCLUSIONS: Our studies are the first to demonstrate a critical role for kinase control of TDP-43 accumulation in SGs and may have important implications for development of treatments for FTD and ALS, targeting cell signal pathway control of TDP-43 aggregation.

Copper and zinc bis(thiosemicarbazonato) complexes with a fluorescent tag: synthesis, radiolabelling with copper-64, cell uptake and fluorescence studies.

The synthesis of new copper(II) bis(thiosemicarbazonato) complexes with an appended pyrene chromophore and their zinc(II) analogues is reported. The new proligands and their copper(II) and zinc(II) complexes were characterised by a combination of NMR, EPR, high performance liquid chromatography, mass spectrometry, electronic spectroscopy and electrochemical measurements. The new copper(II) complexes are fluorescent as a consequence of an appended pyrene substituent that is separated from the sulphur coordinating to the metal ion by five bonds. The emission from the pyrene substituent is concentration- and solvent-dependent with characteristic formation of excimer aggregates. A radioactive (64)Cu complex has been prepared. Cell permeability, intracellular distribution and importantly the ability to cross the nuclear membrane to target DNA were investigated using confocal fluorescence microscopy in a human cancer cell line under normal oxygen conditions and hypoxic conditions. In both cases, there was no evidence of uptake of the copper(II) bis(thiosemicarbazonato) complexes in the area of the cell nucleus.

Membrane-targeted strategies for modulating APP and Abeta-mediated toxicity.

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by numerous pathological features including the accumulation of neurotoxic amyloid-beta (Abeta) peptide. There is currently no effective therapy for AD, but the development of therapeutic strategies that target the cell membrane is gaining increased interest. The amyloid precursor protein (APP) from which Abeta is formed is a membrane-bound protein, and Abeta production and toxicity are both membrane mediated events. This review describes the critical role of cell membranes in AD with particular emphasis on how the composition and structure of the membrane and its specialized regions may influence toxic or benign Abeta/APP pathways in AD. The putative role of copper (Cu) in AD is also discussed, and we highlight how targeting the cell membrane with Cu complexes has therapeutic potential in AD.

Activation of epidermal growth factor receptor by metal-ligand complexes decreases levels of extracellular amyloid beta peptide.

The epidermal growth factor receptor is a receptor tyrosine kinase expressed in a range of tissues and cell-types. Activation of the epidermal growth factor receptor by a number of ligands induces downstream signalling that modulates critical cell functions including growth, survival and differentiation. Abnormal epidermal growth factor receptor expression and activation is also involved in a number of cancers. In addition to its cognate ligands, the epidermal growth factor receptor can be activated by metals such as zinc (Zn) and copper (Cu). Due to the important role of these metals in a number of diseases including neurodegenerative disorders, therapeutic approaches are being developed based on the use of lipid permeable metal-complexing molecules. While these agents are showing promising results in animal models and clinical trials, little is known about the effects of metal-ligand complexes on cell signalling pathways. In this study, we investigated the effects of clioquinol (CQ)-metal complexes on activation of epidermal growth factor receptor. We show here that CQ-Cu complexes induced potent epidermal growth factor receptor phosphorylation resulting in downstream activation of extracellular signal-regulated kinase. Similar levels of epidermal growth factor receptor activation were observed with alternative lipid permeable metal-ligands including neocuproine and pyrrolidine dithiocarbamate. We found that CQ-Cu complexes induced a significant reduction in the level of extracellular Abeta1-40 in cell culture. Inhibition of epidermal growth factor receptor activation by PD153035 blocked extracellular signal-regulated kinase phosphorylation and restored Abeta1-40 levels. Activation of the epidermal growth factor receptor by CQ-Cu was mediated through up-regulation of src kinase activity by a cognate ligand-independent process involving membrane integrins. These findings provide the first evidence that metal-ligand complexes can activate the epidermal growth factor receptor with potentially neuroprotective effects.

The role of metals in modulating metalloprotease activity in the AD brain.

Biometals such as copper and zinc have an important role in Alzheimer's disease (AD). Accumulating evidence indicates that copper homeostasis is altered in AD brain with elevated extracellular and low intracellular copper levels. Studies in animals and cell cultures have suggested that increasing intracellular copper can ameliorate AD-like pathology including amyloid deposition and tau phosphorylation. Modulating copper homeostasis can also improve cognitive function in animal models of AD. Treatments are now being developed that may result in redistribution of copper within the brain. Metal ligands such as clioquinol (CQ), DP-109 or pyrrolidine dithiocarbamate (PDTC) have shown promising results in animal models of AD, however, the actual mode of action in vivo has not been fully determined. We previously reported that CQ-metal complexes were able to increase intracellular copper levels in vitro. This resulted in stimulation of phosphoinositol-3-kinase activity and mitogen activated protein kinases (MAPK). Increased kinase activity resulted in up-regulated matrix metalloprotease (MMP2 and MMP3) activity resulting in enhanced degradation of secreted A beta. These findings are consistent with previous studies reporting metal-mediated activation of MAPKs and MMPs. How this activation occurs is unknown but evidence suggests that copper may be able to activate membrane receptors such as the epidermal growth factor receptor (EGFR) and result in downstream activation of MAPK pathways. This has been supported by studies showing metal-mediated activation of EGFR through ligand-independent processes in a number of cell-types. Our initial studies reveal that copper complexes can in fact activate EGFR. However, further studies are necessary to determine if metal complexes such as CQ-copper induce up-regulation of A beta-degrading MMP activity through this mechanism. Elucidation of this pathway may have important implications for the development of metal ligand based therapeutics for treatment of AD and other neurodegenerative disorders.

Therapeutic treatment of Alzheimer's disease using metal complexing agents.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by deposition of extracellular amyloid plaques, formation of intracellular neurofibrillary tangles and neuronal dysfunction in the brain. A growing body of evidence indicates a central role for biometals such as copper in many critical aspects of AD. The amyloid beta (Abeta) peptide and its parental molecule, the amyloid precursor protein (APP) both modulate Cu and Zn metabolism in the brain. Therefore, aberrant changes to APP or Abeta metabolism could potentially alter biometal homoestasis in AD, leading to increased free radical production and neuronal oxidative stress. Modulation of metal bioavailability in the brain has been proposed as a potential therapeutic strategy for treatment of AD patients. The lipid permeable metal complexing agent, clioquinol (CQ), has shown promising results in animal models of AD and in small clinical trials involving AD patients. Moreover, a new generation of metal-ligand based therapeutics is currently under development. Patents now cover the generation of novel metal ligand structures designed to modulate metal binding to Abeta and quench metal-mediated free radical generation. However, the mechanism by which CQ and other metal complexing agents slows cognitive decline in AD animal models and patients is unknown. Increasing evidence suggests that ligand-mediated redistribution of metals at a cellular level in the brain may be important. Further research will be necessary to fully understand the complex pathways associated with efficacious metal-based pharmaceuticals for treatment of AD.