Copper-chelating Drug Research Articles

Triethylenetetramine (TETA)

The WEEL for triethylenetetramine (TETA; CAS No. 112-24-3) was originally established in 1991 and updated in 1998 and 2009. Recent literature searches to identify new toxicity information were performed in 2016 and January 2021. No new studies or data relevant to the WEEL were identified. TETA is used in manufacturing; the hydrochloride salt of TETA is used as a copper-chelating drug in the treatment of Wilson's disease. TETA is severely irritating to the skin and eyes and produces skin sensitization; however, it is of low to moderate acute toxicity via the oral and dermal routes of exposure. In subchronic studies, signs of toxicity included multi-organ effects (lung, liver, and spleen) in mice, but not rats. TETA was genotoxic/mutagenic in short-term in vitro assays but not in in vivo assays. No data on reproductive toxicity were available. Embryo/fetal toxicity occurred at maternally toxic doses and was associated with copper deficiency. In humans, the use of TETA·2HCl for treatment of Wilson's disease during pregnancy resulted in no miscarriages or fetal abnormalities. No evidence of carcinogenicity was noted in a lifetime dermal study in mice. Based on a subchronic drinking water study in mice, 600 ppm (95mg/kg-day) was determined to be the no-observed-adverse-effect level (NOAEL) and the point of departure (POD). This NOAEL was converted to an equivalent inhalation concentration by adjusting for respiratory rate, interindividual variability, and uncertainty. The resulting 8-h time-weighted average WEEL value of 1 ppm is expected to provide a significant margin of safety against any potential adverse health effects in workers exposed to airborne TETA.

Role of Trientine in Hypertrophic Cardiomyopathy: A Review of Mechanistic Aspects.

Abnormality in myocardial copper homeostasis is believed to contribute to the development of cardiomyopathy. Trientine, a copper-chelating drug used in the management of patients with Wilson’s disease, demonstrates beneficial effects in patients with hypertrophic cardiomyopathy. This review aims to present the updated development of the roles of trientine in hypertrophic cardiomyopathy. The drug has been demonstrated in animal studies to restore myocardial intracellular copper content. However, its mechanisms for improving the medical condition remain unclear. Thus, comprehending its mechanistic aspects in cardiomyopathy is crucial and could help to expedite future research.

Safety profile of D-penicillamine: a comprehensive pharmacovigilance analysis by FDA adverse event reporting system

ABSTRACT Background D-penicillamine (D-pen) is a copper-chelating drug and has immune-modulatory properties. D-pen is used to treat rheumatoid arthritis, Wilson’s disease, and kidney stones (cystinuria). However, associated adverse events (AEs) of D-pen treatment are frequent and often serious. Therefore, a comprehensive assessment of the safety profile of D-pen is urgently needed. Research design and methods We identified and analyzed AEs associated with D-pen between April-1970 to July-2020 from the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) databases and calculated the reported odds ratio (ROR) with 95% confidence intervals (CI) using the disproportionality analysis. Results A total of 9,150,234 AEs related to drugs were reported in the FAERS database, of which 542 were related to D-Pen. We report that D-pen was associated with dystonia (ROR: 20.52; 95%CI: 12.46–33.80), drug hypersensitivity (ROR: 5.42; 95%CI: 3.72–7.90), pancytopenia (ROR: 10.20; 95%CI: 5.61–18.56), joint swelling (ROR: 9.07; 95%CI: 5.51–14.94), renal-impairment (ROR: 6.68; 95%CI: 3.67–12.15), dysphagia (ROR: 5.05; 95%CI: 2.76–8.89), aggravation of condition (ROR: 4.16; 95%CI: 2.60–6.67), congestive cardiac failure (ROR: 4.04; 95%CI: 2.22–7.35), peripheral edema (ROR: 3.77; 95%CI: 2.17–6.55), tremor (ROR: 3.46; 95%CI: 2.00–6.01), pyrexia (ROR: 3.46; 95%CI: 2.00–6.01), and gait disturbance (ROR: 2.41; 95%CI: 1.29–4.52). Conclusions Patients taking D-pen require close monitoring of renal function, blood counts, immunity, liver, cardiac function, and neurological function. D-pen suppresses immune system which maximizes the risk of infection.

Intratumoral Copper Modulates PD-L1 Expression and Influences Tumor Immune Evasion.

Therapeutic checkpoint antibodies blocking programmed death receptor 1/programmed death ligand 1 (PD-L1) signaling have radically improved clinical outcomes in cancer. However, the regulation of PD-L1 expression on tumor cells is still poorly understood. Here we show that intratumoral copper levels influence PD-L1 expression in cancer cells. Deep analysis of the The Cancer Genome Atlas database and tissue microarrays showed strong correlation between the major copper influx transporter copper transporter 1 (CTR-1) and PD-L1 expression across many cancers but not in corresponding normal tissues. Copper supplementation enhanced PD-L1 expression at mRNA and protein levels in cancer cells and RNA sequencing revealed that copper regulates key signaling pathways mediating PD-L1-driven cancer immune evasion. Conversely, copper chelators inhibited phosphorylation of STAT3 and EGFR and promoted ubiquitin-mediated degradation of PD-L1. Copper-chelating drugs also significantly increased the number of tumor-infiltrating CD8+ T and natural killer cells, slowed tumor growth, and improved mouse survival. Overall, this study reveals an important role for copper in regulating PD-L1 and suggests that anticancer immunotherapy might be enhanced by pharmacologically reducing intratumor copper levels. SIGNIFICANCE: These findings characterize the role of copper in modulating PD-L1 expression and contributing to cancer immune evasion, highlighting the potential for repurposing copper chelators as enhancers of antitumor immunity. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/19/4129/F1.large.jpg.

An unexpected antioxidant and redox activity for the classic copper-chelating drug penicillamine

Penicillamine has been widely-used clinically as a copper-chelating drug for the treatment of copper-overload in Wilson's disease. In this study, we found that penicillamine provided marked protection against cytotoxicity induced by tetrachlorohydroquinone (TCHQ), a major toxic metabolite of the well-known wood preservative pentachlorophenol, while other classic copper-chelating agents do not. We found, unexpectedly, that both TCHQ autooxidation and tetrachlorosemiquinone radical (TCSQ•-) formation were remarkably delayed by penicillamine. Further investigation showed that TCSQ•- was reduced back to TCHQ by penicillamine, with the concurrent formation of its corresponding disulfide. These data demonstrated that the protection by penicillamine against TCHQ-induced toxicity was not due to its classic Cu-chelating property, but rather to its reduction of the reactive TCSQ•- to the much less-reactive TCHQ. This is the first report of an unexpected antioxidant and redox activity for penicillamine, which might prove highly relevant to its biological activities.

Antitumour Effect of a Mixture of N-Propyl Polysulfides In Vitro

Abstract Copper serves as a limiting factor for multiple steps of tumour progression, including angiogenesis, growth and metastasis. High levels of copper have been found in a wide spectrum of human cancers. Antitumour activities of copper-chelating drugs have been reported in animal models. Organosulfur compounds (diallyl sulfide, DAS; diallyl disulfide, DADS; S-ethylcysteine, SEC; N-acetylcysteine, NAC) derived from garlic exhibit marked copper-chelating activity. We analysed a mixture of fifteen n-propyl polysulfides (DPPS) for potential antitumour activity against several murine tumour cell lines, including colon carcinoma (CT26), mammary carcinoma (4T1) and melanoma cell lines (B16F10), and compared the effects with the antiproliferative effect in highly proliferative murine mesenchymal stem cells (mMSCs). The effects of the mixture of n-propyl polysulfides (100%) on cell viability were determined using MTT assays. Cell apoptosis was analysed using Annexin V-FITC/PI assays. The results of the MTT assays indicate that this standardized mixture of n-propyl polysulfides has a strong, dose-dependent cytotoxic effect against all three of the tested tumour cell lines (CT26, 4T1, B16F10). The cytotoxic effect of the n-propyl polysulfide mixture against the CT26 and B16F10 cell lines was much stronger than that of cisplatin and was significantly weaker in mMSCs, which are non-cancerous and highly proliferative cells, than in cancer cells. Flow cytometric analysis of CT26 and 4T1 cells revealed that apoptosis was not the dominant mechanism of cell death induced by the n-propyl polysulfide mixture. The n-propyl polysulfide mixture exerted highly cytotoxic activity against murine colon carcinoma and melanoma cell lines, but its antiproliferative activity against mMSCs was significantly lower than that of cisplatin.

Abstract 5806: Exploring the role of copper-dependent lysyl oxidase (LOX) in metastatic growth

Abstract Copper is an enzymatic cofactor required for cellular respiration, iron homeostasis, melanogenesis, neurotransmitter biosynthesis, and connective tissue formation. Copper deficiency in humans is evidenced by Menkes disease, a lethal pediatric disorder caused by mutations in the ATP7A copper transporter. ATP7A, a ubiquitously expressed copper transporting P-type ATPase, transports copper from the cytoplasm into the Golgi complex to supply copper to secreted copper-dependent enzymes. Additionally, ATP7A functions to export copper from cells to avoid copper toxicity. Aberrant copper metabolism is characteristic of many cancers. Copper-chelating drugs such as tetrathiomolybdate or penicillamine have been shown to have anti-angiogenic and anti-neoplastic activity. Copper also appears to be rate limiting for mitogenic signaling pathways necessary for tumor growth such as RAS/RAF/MAPK signaling. The requirement for lysyl oxidase (LOX) proteins in tumor metastasis is further illustrative of copper’s role in cancer biology. Copper-dependent LOX proteins catalyze the oxidation of lysine residues within collagen and/or elastin, stabilizing crosslinks between these fibrous proteins during the formation or remodeling of the extracellular matrix. While research implicates a direct role for LOX proteins in many types of cancer, the use of copper chelators or other strategies to starve LOX enzymes of copper as a therapeutic strategy has been largely overlooked. LOX family members acquire copper in the secretory pathway via the ATP7A protein. Consistent with this requirement, LOX activity is reduced in cultured fibroblasts derived from patients with Menkes disease that lack functional ATP7A protein. As the cancer promoting properties of LOX enzymes have been shown to require catalytic activity, we hypothesize that blocking the ATP7A protein could be a powerful approach to inhibit LOX-dependent pro-tumorigenic and pro-metastatic pathways. In this study, we have found that genetic ablation of ATP7A using CRISPR/Cas9 inhibits the tumorigenic and metastatic potential of a multiple cancer cell lines in vivo. These findings could be attributed to a variety of copper functions or those of copper-dependent enzymes, such as LOX. In this study, we investigate the role of copper-dependent enzymes, such as LOX, using in vitro and in vivo methods. While others have implicated lysyl oxidase secreted by cancer cells in tumorigenesis and metastasis, the contributions of lysyl oxidase at the metastatic site have not been evaluated. Here, I describe a novel conditional mouse model that we use to explore this question. Citation Format: Kimberly Jasmer-McDonald, Michael Petris, Vinit Shanbhag, Nikita Gudekar. Exploring the role of copper-dependent lysyl oxidase (LOX) in metastatic growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5806. doi:10.1158/1538-7445.AM2017-5806

259 - Molecular Mechanism of an Unexpected Novel Antioxidant-Like Activity for the Classic Copper-Chelating Drug Penicillamine

Penicillamine has been widely used clinically as a copper-chelating drug for the treatment of copper overload in Wilson’s disease. Here we found that penicillamine, but not the classic copper chelating agent bathocuproine disulfonate (BCS), provided marked protection against cell cytotoxicity induced by tetrachlorohydroquinone (TCHQ), a major toxic metabolite of the widely used wood preservative pentachlorophenol. The autooxidation process of TCHQ yielding the reactive tetrachlorosemiquinone (TCSQ●–) radical was studied by ESR and UV-visible spectral methods. We found, unexpectedly, the autooxidation process of TCHQ and the time course of TCSQ●– radical formation was remarkably delayed by penicillamine in a concentration dependent manner; In contrast, no delaying effect was observed by BCS. HPLC-MS and ESR studies showed that TCSQ●– radical was reduced to TCHQ by penicillamine, which was concurrently oxidized to its corresponding disulfide form. These data suggest that the protection by penicillamine on TCHQ-induced cytotoxicity was not due to its binding of copper, but rather to its reduction of the reactive TCSQ●– radical to the much less reactive TCHQ. This is the first report demonstrating an unexpected novel antioxidant-like activity for this copper-chelating amino thiol drug, which might prove highly relevant to the biological and pharmaceutical activities of penicillamine.

164. Improvement of Gene Therapy for Wilson Disease

Wilson's disease (WD) is an autosomal recessively inherited copper storage disorder due to mutations in ATP7B gene that causes hepatic and neurologic symptoms. Current treatments are based on lifelong copper chelating drugs, which may cause side effects and do not restore normal copper metabolism. We have recently demonstrated that the administration of an AAV vector expressing ATP7B under the control of a liver specific promoter induces full restoration of copper homeostasis in a mouse model of Wilson's disease. However, the size of the vector genome surpasses the optimal size for AAV packaging, limiting the use of large promoters or additional regulatory sequences such as introns or bigger poly A sequences. In the present work we have designed two truncated versions of ATP7B protein (T1 and T2), and have analyzed their functionality and therapeutic efficacy. ATP7B contains 6 metal binding sites (MBS) in the N-terminal region. T1 presents a deletion of 1 MBS and a fragment of the adjacent one, whereas T2 lacks the first 4 MBS. Both proteins were active since they were able eliminate intracellular excess of copper in an in vitro system. The administration of recombinant AAV vectors carrying the truncated proteins under the control of a liver specific promoter was able to reduce liver damage and urinary copper excretion in the murine model, but T1 was less efficient than the WT ATP7B gene. In contrast, T2 showed full capacity to normalize these parameters. Furthermore, T2 was more efficient than WT in restoring ceruloplasmin oxidase activity in serum. In conclusion, we have identified a fully functional truncated version of ATP7B protein that will reduce the size of the therapeutic AAV vector genome and allow the introduction of additional regulatory elements.

From the Editor’s desk...: February 2016

Selection of the month Gene therapy for Wilson disease Current treatments for Wilson Disease (WD) are based on lifelong copper chelating drugs, which may cause side effects and do not restore normal copper metabolism. In this work, Murillo et al. assessed the efficacy of gene therapy by transducing the liver of the Atp7b −/− WD mouse model with an adenovirus encoding the human ATP7B cDNA. They observed a dose-dependent therapeutic effect of the gene therapy approach manifested by the reduction of serum transaminases and urinary copper excretion , normalization of serum holoceruloplasmin, and restoration of physiological biliary copper excretion in response to copper overload. The liver of treated animals showed normalization of copper content and absence of histological alterations. These promising preclinical studies highlight the potential of gene therapy to treat patients with WD.

Long-term metabolic correction of Wilson’s disease in a murine model by gene therapy

Wilson's disease (WD) is an autosomal recessively inherited copper storage disorder due to mutations in the ATP7B gene that causes hepatic and neurologic symptoms. Current treatments are based on lifelong copper chelating drugs and zinc salts, which may cause side effects and do not restore normal copper metabolism. In this work we assessed the efficacy of gene therapy to treat this condition. We transduced the liver of the Atp7b(-/-) WD mouse model with an adeno-associated vector serotype 8 (AAV8) encoding the human ATP7B cDNA placed under the control of the liver-specific α1-antitrypsin promoter (AAV8-AAT-ATP7B). After vector administration we carried out periodic evaluation of parameters associated with copper metabolism and disease progression. The animals were sacrificed 6months after treatment to analyze copper storage and hepatic histology. We observed a dose-dependent therapeutic effect of AAV8-AAT-ATP7B manifested by the reduction of serum transaminases and urinary copper excretion, normalization of serum holoceruloplasmin, and restoration of physiological biliary copper excretion in response to copper overload. The liver of treated animals showed normalization of copper content and absence of histological alterations. Our data demonstrate that AAV8-AAT-ATP7B-mediated gene therapy provides long-term correction of copper metabolism in a clinically relevant animal model of WD providing support for future translational studies.

Tumor-Specific Induction of Oxidative Stress with Dichloroacetate and Auranofin May Complement the Efficacy of PARP Inhibition in Cancer Control

PARP inhibition can improve survival in cancer patients whose tumors have impaired capacity for homologous recombination, such as germ line or somatic mutations in BRCA. The efficacy of such therapy should be greater if the rate at which cancer cell DNA incurs single-strand breaks is enhanced. Since oxidative stress promotes formation of such breaks, measure which boost oxidative stress in cancer – preferable somewhat selectively – may be worthwhile adjuvants to PARP therapy. In the many cancers that express the Warburg phenomenon, dichloroacetate can promote increased mitochondrial generation of oxidants by directing more pyruvate to oxidation in the Krebs cycle. Concurrent administration of the arthritis drug auranofin could further enhance mitochondrial release of hydrogen peroxide by indirectly inhibiting peroxiredoxin-3, the chief mitochondrial source of peroxidase activity. The copper-chelating drug tetrathiomolybdate, employed in cancer therapy as an anti-angiogenic agent, can boost superoxide levels by diminishing activity of the copper-zinc-dependent cytosolic superoxide dismutase. Episodic intravenous infusion of high-dose ascorbate could also be employed to increase oxidative stress in the cancer and thereby complement PARP inhibitor therapy. The potential of dichloroacetate, auranofin, tetrathiomolybdate, and intravenous ascorbate to enhance the cancer-retardant efficacy of olaparib (or other PARP inhibitors) could be assessed in cell culture and rodent models.

An Unexpected Novel Antioxidant Activity for Penicillamine, a Classic Copper-Chelating Drug for the Treatment of Wilson's Disease

An Unexpected Novel Antioxidant Activity for Penicillamine, a Classic Copper-Chelating Drug for the Treatment of Wilson's Disease

Enhancing Tumor-Specific Uptake of the Anticancer Drug Cisplatin with a Copper Chelator

Uptake of the anticancer drug cisplatin is mediated by the copper transporter CTR1 in cultured cells. Here we show in human ovarian tumors that low levels of Ctr1 mRNA are associated with poor clinical response to platinum-based therapy. Using a mouse model of human cervical cancer, we demonstrate that combined treatment with a copper chelator and cisplatin increases cisplatin-DNA adduct levels in cancerous but not in normal tissues, impairs angiogenesis, and improves therapeutic efficacy. The copper chelator also enhances the killing of cultured human cervical and ovarian cancer cells with cisplatin. Our results identify the copper transporter as a therapeutic target, which can be manipulated with copper chelating drugs to selectively enhance the benefits of platinum-containing chemotherapeutic agents.

Ammonium tetrathiomolybdate delays onset, prolongs survival, and slows progression of disease in a mouse model for amyotrophic lateral sclerosis

Mutations in copper/zinc superoxide dismutase (SOD1) cause a form of familial amyotrophic lateral sclerosis (ALS). The pathogenesis of familial ALS may be associated with aberrant copper chemistry through a cysteine residue in mutant SOD1. Ammonium tetrathiomolybdate (TTM) is a copper-chelating drug that is capable of removing a copper ion from copper-thiolate clusters, such as SOD1. We found that TTM exerted therapeutic benefits in a mouse model of familial ALS (SOD1 G93A ). TTM treatment significantly delayed disease onset, slowed disease progression and prolonged survival by approximately 20%, 42% and 25%, respectively. TTM also effectively depressed the spinal copper ion level and inhibited lipid peroxidation, with a significant suppression of SOD1 enzymatic activity in SOD1 G93A . These results support the hypothesis that aberrant copper chemistry through a cysteine residue plays a critical role in mutant SOD1 toxicity and that TTM may be a promising therapy for familial ALS with SOD1 mutants.

Tetrathiomolybdate Protects against Bile Duct Ligation-Induced Cholestatic Liver Injury and Fibrosis

Tetrathiomolybdate (TM), a potent copper-chelating drug, was initially developed for the treatment of Wilson's disease. Our working hypothesis is that the fibrotic pathway is copper-dependent. Because biliary excretion is the major pathway for copper elimination, a bile duct ligation (BDL) mouse model was used to test the potential protective effects of TM. TM was given in a daily dose of 0.9 mg/mouse by means of intragastric gavage 5 days before BDL. All the animals were killed 5 days after surgery. Plasma liver enzymes and total bilirubin were markedly decreased in TM-treated BDL mice. TM also inhibited the increase in plasma levels of tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta1 seen in BDL mice. Cholestatic liver injury was markedly attenuated by TM treatment as shown by histology. Hepatic collagen deposition was significantly decreased, and it was paralleled by a significant suppression of hepatic smooth muscle alpha-actin and fibrogenic gene expression in TM-treated BDL mice. Although the endogenous antioxidant ability was enhanced, oxidative stress as shown by malondialdehyde and 4-hydroxyalkenals, hepatic glutathione/oxidized glutathione ratio, was not attenuated by TM treatment, suggesting the protective mechanism of TM may be independent of oxidative stress. In summary, TM attenuated BDL-induced cholestatic liver injury and fibrosis in mice, in part by inhibiting TNF-alpha and TGF-beta1 secretion. The protective mechanism seems to be independent of oxidative stress. Our data provide further evidence that TM might be a potential therapy for hepatic fibrosis.

Introducing Single-Nucleotide Polymorphism Markers in the Diagnosis of Wilson Disease

Wilson disease (WD) represents a monogenic disease resulting in copper accumulation within tissues. Incidence is estimated to be approximately 1:30 000. Symptoms include acute and chronic liver disease, hemolysis, and neurodegenerative and psychiatric symptoms (1). The first symptom may be acute liver failure. Death or liver transplantation in WD is common. The European Liver Transplant Registry recorded 706 liver transplantations for WD from 1 January 1988 to 31 December 2005, underlining the relevance of this disease burden. Because symptoms and disease course are variable, diagnosis can be difficult. Effective treatment for WD such as copper chelating drugs and zinc is available, which usually prevents disease progression. Therefore, a simple, rapid and diagnostic test is required for WD, ideally to identify patients before symptoms appear. First symptoms have been reported in patients as young as 2 years of age (2)(3). Thus screening tests for WD at least at the age of 2 years would be appropriate. Penetrance of disease is expected …

Copper‐catalyzed ascorbate oxidation results in glyoxal/AGE formation and cytotoxicity

Previously we showed that 10 muM glyoxal compromised hepatocyte resistance to hydrogen peroxide (H(2)O(2)) by increasing glutathione (GSH) and NADPH oxidation and decreasing mitochondrial membrane potential (MMP) before cytotoxicity ensued. Since transition metal-catalyzed oxidation of ascorbate (Asc) has been shown to result in the generation of both glyoxal and H(2)O(2), we hypothesized that glyoxal formation during this process compromises hepatocyte resistance to H(2)O(2). We used isolated rat hepatocytes and incubated them with Asc/copper and measured cytotoxicity, glyoxal levels, H(2)O(2), GSH levels, and MMP. To investigate the role of Asc/copper on glyoxal-BSA adducts, we measured the appearance of advanced glycation end-products (AGE) in the presence and absence of catalase or aminoguanidine (AG). Asc/copper increased glyoxal and H(2)O(2) formation. Hepatocyte GSH levels were decreased and cytotoxicity ensued after a collapse of the hepatocyte MMP. Glyoxal traps protected hepatocytes against Asc/copper-induced cytotoxicity. In cell-free studies with BSA, incubation with Asc and copper resulted in glyoxal-hydroimidazolone formation, which was decreased by both AG and catalase. To the best of our knowledge, this is the first study that illustrates the importance of glyoxal production by transition metal-catalyzed Asc autoxidation. Understanding this mechanism of toxicity could lead to the development of novel copper chelating drug therapies to treat diabetic complications.

A wholly nutritional ‘multifocal angiostatic therapy’ for control of disseminated cancer

A great deal of effort is now being devoted to the development of new drugs that hopefully will control the spread of inoperable cancer by safely inhibiting tumor-evoked angiogenesis. However, there is growing evidence that certain practical nutritional measures have the potential to slow tumor angiogenesis, and it is reasonable to anticipate that, by combining several measures that work in distinct but complementary ways to impede the angiogenic process, a clinically useful ‘multifocal angiostatic therapy’ (MAT) might be devised. Several measures which might reasonably be included in such a protocol are discussed below, and include: a low-fat, low-glycemic index vegan diet, which may down-regulate the systemic IGF-I activity that supports angiogenesis; supplemental omega-3-rich fish oil, which has been shown to inhibit endothelial expression of Flk-1, a functionally crucial receptor for VEGF, and also can suppress tumor production of pro-angiogenic eicosanoids; high-dose selenium, which has recently been shown to inhibit tumor production of VEGF; green tea polyphenols, which can suppress endothelial responsiveness to both VEGF and fibroblast growth factor; and high-dose glycine, whose recently reported angiostatic activity may reflect inhibition of endothelial cell mitosis, possibly mediated by activation of glycine-gated chloride channels. In light of evidence that tumor-evoked angiogenesis has a high requirement for copper, copper depletion may have exceptional potential as an angiostatic measure, and is most efficiently achieved with the copper-chelating drug tetrathiomolybdate. If logistical difficulties make it difficult to acquire this experimental drug, high-dose zinc supplementation can achieve a slower depletion of the body’s copper pool, and in any case can be used as maintenance therapy to maintain an adequate level of copper depletion. A provisional protocol is offered for a nutritionally based MAT entailing a vegan diet and supplemental intakes of fish oil, selenium, green tea polyphenols, glycine, and zinc. Inasmuch as cox-2 is overexpressed in many cancers, and cAMP can boost tumor production of various angiogenic factors as well as autogenous growth factors, adjunctive use of cox-2-specific NSAIDS may be warranted in some cases.

Red blood cell copper, zinc superoxide dismutase activity is higher in Alzheimer's disease and is decreased by d-penicillamine

Copper, zinc superoxide dismutase (Cu, Zn SOD) activity was measured in red blood cells (RBC) of 32 patients affected by Alzheimer's disease (AD), eight other AD patients treated with the copper-chelating agent d-penicillamine, 13 first-degree relatives and 22 controls. All AD patients enrolled in our study showed a higher level of Cu, Zn SOD activity early in the disease. No correlation between apolipoprotein E genotype and SOD activity was found in AD patients. d-penicillamine treatment of AD patients for 24 weeks lowered the enzyme activity even below the control value. These results support the hypothesis that a higher level of Cu, Zn SOD activity in RBC can be an early diagnostic peripheral marker of this disease and a sensor to monitor treatments with copper-chelating drugs.