A paradoxical relationship between Resveratrol and copper (II) with respect to degradation of DNA and RNA

Exploiting the damaging effects of ROS for therapeutic use by deactivating cell-free chromatin: the alchemy of resveratrol and copper

Cell-free chromatin particles (cfChPs) that circulate in blood, or those that are released locally from dying cells, have myriad pathological effects. They can horizontally transfer themselves into healthy cells to induce DNA damage and activate inflammatory and apoptotic pathways. It has been proposed that repeated and lifelong assault on healthy cells by cfChPs may be the underlying cause of ageing and multiple age related disorders including cancer. The damaging effects of cfChPs can be minimized by deactivating them via the medium of ROS generated by admixing the nutraceuticals resveratrol (R) and copper (Cu). The antioxidant R acts as a pro-oxidant in the presence of Cu by its ability to catalyse the reduction of Cu(II) to Cu(I) with the generation of ROS via a Fenton-like reaction which can deactivate extra-cellular cfChPs. This perspective article explores the possibility of using the damaging potential of ROS for therapeutic purposes. It discusses the ability of ROS generating nutraceuticals R-Cu to deactivate the extracellular cfChPs without damaging effects on the genomic DNA. As cfChPs play a key role in activation of various disease associated pathways, R-Cu mediated deactivation of these pathways may open up multiple novel avenues for therapy. These findings have considerable translational implications which deserve further investigation by the way of well-designed randomised clinical trials.

A pro-oxidant combination of resveratrol and copper down-regulates multiple biological hallmarks of ageing and neurodegeneration in mice

Billions of cells die in the body every day, and cell-free chromatin particles (cfChPs) which are released from them enter into the extracellular compartments of the body, including into the circulation. cfChPs are known to readily enter into healthy cells to damage their DNA and activate apoptotic and inflammatory pathways. We have hypothesized that lifelong assault on healthy cells by cfChPs is the underlying cause of ageing, and that ageing could be retarded by deactivating extra-cellular cfChPs. The latter can be effected by oxygen radicals that are generated upon admixing the nutraceuticals resveratrol and copper (R-Cu). The present study investigated whether prolonged administration of R-Cu would retard biological hallmarks of ageing. C57Bl/6 mice were divided into 3 equal groups; one group was sacrificed at age 3 months, and which acted as young controls. The remaining mice were allowed to age, and at age 10 months the experimental ageing group was given R-Cu by oral gavage twice daily for further 12 months at a dose of 1 mg/kg of R and 0.1 μg/kg of Cu. The control ageing group was given water by oral gavage twice daily for 12 months. Animals of both groups were sacrificed at age 22 months. R-Cu treatment led to reduction of several biological hallmarks of ageing in brain cells which included telomere attrition, amyloid deposition, DNA damage, apoptosis, inflammation, senescence, aneuploidy and mitochondrial dysfunction. R-Cu treatment also led to significant reduction in blood levels of glucose, cholesterol and C-reactive protein. These findings suggest that cfChPs may act as global instigators of ageing and neurodegeneration, and that therapeutic use of R-Cu may help to make healthy ageing an attainable goal.

A novel pro-oxidant combination of resveratrol and copper reduces transplant related toxicities in patients receiving high dose melphalan for multiple myeloma (RESCU 001)

Background

Transplant related toxicity is a major therapeutic challenge. We have previously reported that the toxicity of chemotherapy is largely not directly because of the drugs themselves; rather it is mainly due to DNA damage, apoptosis and hyper-inflammation triggered by cell-free chromatin particles that are released because of drug-induced host cell death. Cell-free chromatin particles can be inactivated by free-radicals which are generated when the nutraceuticals resveratrol and copper are administered orally. We investigated if a combination of resveratrol and copper would reduce transplant related toxicities in an exploratory, prospective dose-escalation study.

Patients and methods

Twenty-five patients with multiple myeloma were enrolled between March 2017 to August 2019. Patients were divided into 3 groups: control (Group 1, N = 5) received vehicle alone; group 2 (N = 15) received resveratrol-copper at dose level I (resveratrol = 5.6 mg and copper = 560 ng); group 3 (N = 5) received resveratrol-copper at dose level II (resveratrol = 50 mg and copper = 5 μg). The dose was given twice daily with the first dose administered 48 hours before administering melphalan and continued until day +21 post-transplant. Common Terminology Criteria for Adverse Events version 4.02 was used to assess toxicities which included oral mucositis, nausea, vomiting and diarrhea. Measurement of inflammatory cytokines was done by ELISA.

Results

All patients (100%) in the control group developed grade 3/4 oral mucositis compared to 8/20 (40%) in both resveratrol-copper group 2 plus group 3 combined (P = 0.039). Reduction in inflammatory cytokines: salivary TNF - α (p = 0.012) and IL—1β (p = 0.009) in dose level I but not in dose level II was observed.

Conclusions

A combination of resveratrol-copper reduced transplant related toxicities in patients with multiple myeloma receiving high dose melphalan. We conclude that relatively inexpensive nutraceuticals may be useful as adjuncts to chemotherapy to reduce its toxicity.

Registration

The trial was registered under Clinical Trial Registry of India (no.CTRI/2018/02/011905).

A New Perspective on the Origin of DNA Double-Strand Breaks and Its Implications for Ageing

It is estimated that 10-50 DNA double-strand breaks (DSBs) occur in a nucleated human cell per cell cycle. We reviewed the present state of knowledge and hypothesized that the currently accepted mechanisms cannot explain such high frequency of DSBs occurring daily under normal physiological conditions. We propose an alternative model that implicates illegitimate genomic integration into healthy cells of cell-free chromatin (cfCh) particles released from the billions of cells that die in the body every day. Repeated genomic integration of cfCh may have catastrophic consequences for the cell, such as DSBs, their faulty repair by nonhomologous end joining (NHEJ) followed by apoptosis with release of more cfCh which would integrate into genomes of surrounding cells. This can creates a vicious cycle of cfCh integration, DSBs, NHEJ, and more apoptosis, thereby providing a potential explanation as to why so many billions of cells die in the body on a daily basis. We also recount the recent observation that cfCh integration and the resulting DSBs activate inflammatory cytokines. This leads us to propose that concurrent DSBs and induction of inflammation occurring throughout life may be the underlying cause of ageing, degenerative disorders, and cancer. Finally, we discuss the prospect that agents that can inactivate/degrade cfCh may hold the key to making healthy ageing a realizable goal.

Cell-free chromatin particles released from dying host cells are global instigators of endotoxin sepsis in mice

We have earlier reported that cell-free chromatin (cfCh) particles that are released from dying cells, or those that circulate blood, can readily enter into healthy cells, illegitimately integrate into their genomes and induce dsDNA breaks, apoptosis and intense activation of inflammatory cytokines. We hypothesized that sepsis is caused by cfCh released from dying host cells following microbial infection leading to bystander host cell apoptosis and inflammation which are perpetuated in a vicious cycle with release of more cfCh from dying host cells. To test this hypothesis we used three cfCh inactivating agents namely 1) anti-histone antibody complexed nanoparticles which inactivate cfCh by binding to histones; 2) DNase I which inactivates cfCh by degrading its DNA component, and 3) a novel pro-oxidant combination of Resveratrol and Copper which, like DNase I, inactivates cfCh by degrading its DNA component. Female C57 BL/6 mice, 6–8 weeks old, were administered a single i.p. injection of LPS at a dose of 10 mg/Kg or 20 mg/Kg with or without concurrent treatment with the above cfCh inactivating agents. Administration of cfCh inactivating agents concurrently with LPS resulted in prevention of following pathological parameters: 1) release of cfCh in extra-cellular spaces of brain, lung and heart and in circulation; 2) release of inflammatory cytokines in circulation; 3) activation of DNA damage, apoptosis and inflammation in cells of thymus, spleen and in PBMCs; 4) DNA damage, apoptosis and inflammation in cells of lung, liver, heart, brain, kidney and small intestine; 5) liver and kidney dysfunction and elevation of serum lactate; 6) coagulopathy, fibrinolysis and thrombocytopenia; 7) lethality. We conclude that cfCh that are released from dying host cells in response to bacterial endotoxin represents a global instigator of sepsis. cfCh inactivation may provide a novel approach to management of sepsis in humans.

Illegitimate and Repeated Genomic Integration of Cell-Free Chromatin in the Aetiology of Somatic Mosaicism, Ageing, Chronic Diseases and Cancer

Emerging evidence suggests that an individual is a complex mosaic of genetically divergent cells. Post-zygotic genomes of the same individual can differ from one another in the form of single nucleotide variations, copy number variations, insertions, deletions, inversions, translocations, other structural and chromosomal variations and footprints of transposable elements. High-throughput sequencing has led to increasing detection of mosaicism in healthy individuals which is related to ageing, neuro-degenerative disorders, diabetes mellitus, cardiovascular diseases and cancer. These age-related disorders are also known to be associated with significant increase in DNA damage and inflammation. Herein, we discuss a newly described phenomenon wherein the genome is under constant assault by illegitimate integration of cell-free chromatin (cfCh) particles that are released from the billions of cells that die in the body every day. We propose that such repeated genomic integration of cfCh followed by dsDNA breaks and repair by non-homologous-end-joining as well as physical damage to chromosomes occurring throughout life may lead to somatic/chromosomal mosaicism which would increase with age. We also discuss the recent finding that genomic integration of cfCh and the accompanying DNA damage is associated with marked activation of inflammatory cytokines. Thus, the triple pathologies of somatic mosaicism, DNA/chromosomal damage and inflammation brought about by a common mechanism of genomic integration of cfCh may help to provide an unifying model for the understanding of aetiologies of the inter-related conditions of ageing, degenerative disorders and cancer.

Prevention of radiation-induced bystander effects by agents that inactivate cell-free chromatin released from irradiated dying cells

Radiation-induced bystander effect (RIBE) is a poorly understood phenomenon wherein non-targeted cells exhibit effects of radiation. We have reported that cell-free chromatin (cfCh) particles that are released from dying cells can integrate into genomes of surrounding healthy cells to induce DNA damage and inflammation. This raised the possibility that RIBE might be induced by cfCh released from irradiated dying cells. When conditioned media from BrdU-labeled irradiated cells were passed through filters of pore size 0.22 µm and incubated with unexposed cells, BrdU-labeled cfCh particles could be seen to readily enter their nuclei to activate H2AX, active Caspase-3, NFκB, and IL-6. A direct relationship was observed with respect to activation of RIBE biomarkers and radiation dose in the range of 0.1-0 Gy. We confirmed by FISH and cytogenetic analysis that cfCh had stably integrated into chromosomes of bystander cells and had led to extensive chromosomal instability. The above RIBE effects could be abrogated when conditioned media were pre-treated with agents that inactivate cfCh, namely, anti-histone antibody complexed nanoparticles (CNPs), DNase I and a novel DNA degrading agent Resveratrol-copper (R-Cu). Lower hemi-body irradiation with γ-rays (0.1-50 Gy) led to activation of H2AX, active Caspase-3, NFκB, and IL-6 in brain cells in a dose-dependent manner. Activation of these RIBE biomarkers could be abrogated by concurrent treatment with CNPs, DNase I and R-Cu indicating that activation of RIBE was not due to radiation scatter to the brain. RIBE activation was seen even when mini-beam radiation was delivered to the umbilical region of mice wherein radiation scatter to brain was negligible and could be abrogated by cfCh inactivating agents. These results indicate that cfCh released from radiation-induced dying cells are activators of RIBE and that it can be prevented by treatment with appropriate cfCh inactivating agents.

Cell-free chromatin from dying cancer cells integrate into genomes of bystander healthy cells to induce DNA damage and inflammation

Bystander cells of the tumor microenvironment show evidence of DNA damage and inflammation that can lead to their oncogenic transformation. Mediator(s) of cell-cell communication that brings about these pro-oncogenic pathologies has not been identified. We show here that cell-free chromatin (cfCh) released from dying cancer cells are the key mediators that trigger both DNA damage and inflammation in the surrounding healthy cells. When dying human cancer cells were cultured along with NIH3T3 mouse fibroblast cells, numerous cfCh emerged from them and rapidly entered into nuclei of bystander NIH3T3 cells to integrate into their genomes. This led to activation of H2AX and inflammatory cytokines NFκB, IL-6, TNFα and IFNγ. Genomic integration of cfCh triggered global deregulation of transcription and upregulation of pathways related to phagocytosis, DNA damage and inflammation. None of these activities were observed when living cancer cells were co-cultivated with NIH3T3 cells. However, upon intravenous injection into mice, both dead and live cells were found to be active. Living cancer cells are known to undergo extensive cell death when injected intravenously, and we observed that cfCh emerging from both types of cells integrated into genomes of cells of distant organs and induced DNA damage and inflammation. γH2AX and NFκB were frequently co-expressed in the same cells suggesting that DNA damage and inflammation are closely linked pathologies. As concurrent DNA damage and inflammation is a potent stimulus for oncogenic transformation, our results suggest that cfCh from dying cancer cells can transform cells of the microenvironment both locally and in distant organs providing a novel mechanism of tumor invasion and metastasis. The afore-described pro-oncogenic pathologies could be abrogated by concurrent treatment with chromatin neutralizing/degrading agents suggesting therapeutic possibilities.