RLIP76, a glutathione-conjugate transporter, plays a major role in the pathogenesis of metabolic syndrome

Abnormal interaction of Rlip with mutant APP/Abeta and phosphorylated tau reduces wild-type Rlip levels and disrupt Rlip function in Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease that affects a large proportion of the aging population. RalBP1 (Rlip) is a stress-activated protein, that plays an important role in aging and neurodegenerative diseases such as Alzheimer's disease. Mutant APP and mutant Tau interact with the Rlip protein which leads to decreased wild-type Rlip levels and disrupt Rlip function in Alzheimer's disease. Rlip is a promising new target for aging, Alzheimer's disease, and other neurological diseases.

Regression of ovarian cancer xenografts by depleting or inhibiting RLIP

Ovarian cancer (OC) is the most prevalent and deadly cancer of the female reproductive system. Women will continue to be impacted by OC-related morbidity and mortality. Despite the fact that chemotherapy with cisplatin is the main component as the first-line anticancer treatment for OC, chemoresistance and unfavorable side effects are important obstacles to effective treatment. Targets for effective cancer therapy are required for cancer cells but not for non-malignant cells because they are expressed differently in cancer cells compared to normal cells. Targets for cancer therapy should preferably be components that already exist in biochemical and signalling frameworks and that significantly contribute to the development of cancer or regulate the response to therapy. RLIP is an important mercapturic acid pathway transporter that is crucial for survival and therapy resistance in cancers, therefore, we examined the role of RLIP in regulating essential signalling proteins involved in relaying the inputs from upstream survival pathways and mechanisms contributing to chemo-radiotherapy resistance in OC. The findings of our research offer insight into a novel anticancer effect of RLIP depletion/inhibition on OC and might open up new therapeutic avenues for OC therapy.

Rlip overexpression reduces oxidative stress and mitochondrial dysfunction in Alzheimer's disease: Mechanistic insights

Alzheimer's disease (AD) is a neurodegenerative disease that affects a large proportion of the aging population. RalBP1 (Rlip) is a stress-activated protein that plays a crucial role in oxidative stress and mitochondrial dysfunction in aging and neurodegenerative diseases but its precise role in the progression of AD is unclear. The purpose of our study is to understand the role of Rlip in the progression and pathogenesis of AD in mutant APP/amyloid beta (Aβ)-expressed mouse primary hippocampal (HT22) hippocampal neurons. In the current study, we used HT22 neurons that express mAPP, transfected with Rlip-cDNA and/or RNA silenced, and studied cell survival, mitochondrial respiration, mitochondrial function, immunoblotting & immunofluorescence analysis of synaptic and mitophagy protein's and colocalization of Rlip and mutant APP/Aβ proteins and mitochondrial length and number. We also assessed Rlip levels in autopsy brains from AD patients and control subjects. We found cell survival was decreased in mAPP-HT22 cells and RNA-silenced HT22 cells. However, cell survival was increased in Rlip-overexpressed mAPP-HT22 cells. Oxygen consumption rate (OCR) was decreased in mAPP-HT22 cells and RNA-silenced Rlip-HT22 cells. OCR was increased in Rlip-overexpressed in mAPP-HT22 cells. Mitochondrial function was defective in mAPP-HT22 cells and RNA silenced Rlip in HT22 cells, however, it was rescued in Rlip overexpressed mAPP-HT22 cells. Synaptic and mitophagy proteins were decreased in mAPP-HT22 cells, further reducing RNA-silenced Rlip-HT22 cells. However, these were increased in mAPP+Rlip-HT22 cells. Colocalization analysis revealed Rlip is colocalized with mAPP/Aβ. An increased number of mitochondria and decreased mitochondrial length were found in mAPP-HT22 cells. These were rescued in Rlip overexpressed mAPP-HT22 cells. Reduced Rlip levels were found in autopsy brains from AD patients. These observations strongly suggest that Rlip deficiency causes oxidative stress/mitochondrial dysfunction and Rlip overexpression reduced these defects.

Rlip Reduction Induces Oxidative Stress and Mitochondrial Dysfunction in Mutant Tau-Expressed Immortalized Hippocampal Neurons: Mechanistic Insights

RalBP1 (Rlip) is a stress-activated protein that is believed to play a large role in aging and neurodegenerative diseases such as Alzheimer's disease (AD) and other tauopathies. The purpose of our study was to understand the role of Rlip in mutant Tau-expressed immortalized hippocampal HT22 cells. In the current study, we used mutant Tau (mTau)-expressed HT22 neurons and HT22 cells transfected with Rlip-cDNA and/or silenced RNA, and studied the cell survival, mitochondrial respiration, mitochondrial function, immunoblotting, and immunofluorescence analysis of synaptic and mitophagy proteins and the colocalization of Rlip and mTau proteins. We found Rlip protein levels were reduced in mTau-HT22 cells, Rlip silenced HT22 cells, and mTau + Rlip RNA silenced HT22 cells; on the other hand, increased Rlip levels were observed in Rlip cDNA transfected HT22 cells. We found cell survival was decreased in mTau-HT22 cells and RNA-silenced HT22 cells. However, cell survival was increased in Rlip-overexpressed mTau-HT22 cells. A significantly reduced oxygen consumption rate (OCR) was found in mTau-HT22 cells and in RNA-silenced Rlip-HT22 cells, with an even greater reduction in mTau-HT22 + Rlip RNA-silenced HT22 cells. A significantly increased OCR was found in Rlip-overexpressed HT22 cells and in all groups of cells that overexpress Rlip cDNA. Mitochondrial function was defective in mTau-HT22 cells, RNA silenced Rlip in HT22 cells, and was further defective in mTau-HT22 + Rlip RNA-silenced HT22 cells; however, it was rescued in Rlip overexpressed in all groups of HT22 cells. Synaptic and mitophagy proteins were decreased in mTau-HT22 cells, and further reductions were found in RNA-silenced mTau-HT22 cells. However, these were increased in mTau + Rlip-overexpressed HT22 cells. An increased number of mitochondria and decreased mitochondrial length were found in mTau-HT22 cells. These were rescued in Rlip-overexpressed mTau-HT22 cells. These observations strongly suggest that Rlip deficiency causes oxidative stress/mitochondrial dysfunction and Rlip overexpression reverses these defects. Overall, our findings revealed that Rlip is a promising new target for aging, AD, and other tauopathies/neurological diseases.

RLIP: A necessary transporter protein for translating oxidative stress into pro-obesity and pro-carcinogenic signaling

Previously, we showed that knockout mice homozygous for deficiency of the mercapturic acid pathway (MAP) transporter protein, RLIP (RLIP^-/-), are resistant to chemical carcinogenesis, inflammation, and metabolic syndrome (MetS). We also found that RLIP^-/- mice are highly resistant to obesity caused by a high-fat diet (HFD). Interestingly, these studies showed that kinase, cytokine, and adipokine signaling that are characteristics of obesity were blocked despite the presence of increased oxidative stress in RLIP^-/- mice. The deficiencies in obesity-inducing kinase, cytokine, and adipokine signaling were attributable to a lack of clathrin-dependent endocytosis (CDE), a process that is severely deficient in RLIP^-/- mice. Because CDE is also necessary for carcinogenic signaling through EGF, WNT, TGFβ and other cancer-specific peptide hormones, and because RLIP^-/- mice are cancer-resistant, we reasoned that depletion of RLIP by an antisense approach should cause cancer regression in human cancer xenografts. This prediction has been confirmed in studies of xenografts from lung, kidney, prostate, breast, and pancreatic cancers and melanoma. Because these results suggested an essential role for RLIP in carcinogenesis, and because our studies have also revealed a direct interaction between p53 and RLIP, we reasoned that if RLIP played a central role in carcinogenesis, that development of lymphoma in p53^-/- mice, which normally occurs by the time these mice are 6 months old, could be delayed or prevented by depleting RLIP. Recent studies described herein have confirmed this hypothesis, showing complete suppression of lymphomagenesis in p53^-/- mice treated with anti-RLIP antisense until the age of 8 months. All control mice developed lymphoma in the thymus or testis as expected. These findings lead to a novel paradigm predicting that under conditions of increased oxidative stress, the consequent increased flux of metabolites in the MAP causes a proportional increase in the rate of CDE. Because CDE inhibits insulin and TNF signaling but promotes EGF, TGFβ, and Wnt signaling, our model predicts that chronic stress-induced increases in RLIP (and consequently CDE) will induce insulin-resistance and enhance predisposition to cancer. Alternatively, generalized depletion of RLIP would antagonize the growth of malignant cells, and concomitantly exert therapeutic insulin-sensitizing effects. Therefore, this review focuses on how targeted depletion or inhibition of RLIP could provide a novel target for treating both obesity and cancer.

Fu Brick Tea Manages HFD/STZ-Induced Type 2 Diabetes by Regulating the Gut Microbiota and Activating the IRS1/PI3K/Akt Signaling Pathway

The antidiabetic effects of Fu brick tea aqueous extract (FTE) and its underlying molecular mechanism in type 2 diabetes mellitus (T2DM) mice were investigated. FTE treatment significantly relieved dyslipidemia, insulin resistance (IR), and hepatic oxidative stress caused by T2DM. FTE also ameliorated the T2DM-induced gut dysbiosis by decreasing the Firmicutes/Bacteroidota (F/B) ratio at the phylum level and promoting the proliferation of Bifidobacterium, Parabacteroides, and Roseburia at the genus level. Besides, FTE significantly improved colonic short-chain fatty acid levels of T2DM mice. Furthermore, the antidiabetic effects of FTE were proved to be mediated by the IRS1/PI3K/Akt and AMPK-mediated gluconeogenesis signaling pathways. Metabolomics analysis illustrated that FTE recovered the levels of 28 metabolites associated with T2DM to the levels of normal mice. Taken together, these findings suggest that FTE can alleviate T2DM by reshaping the gut microbiota, activating the IRS1/PI3K/Akt pathway, and regulating intestinal metabolites.

CDDO-Me Attenuates CA1 Neuronal Death by Facilitating RalBP1-Mediated Mitochondrial Fission and 4-HNE Efflux in the Rat Hippocampus Following Status Epilepticus

Ras-related protein Ral-A (RalA)-binding protein 1 (RalBP1, also known as Ral-interacting protein of 76 kDa (RLIP76) or Ral-interacting protein 1 (RLIP1 or RIP1)) is involved in the efflux of 4-hydroxynonenal (4-HNE, an end product of lipid peroxidation), as well as mitochondrial fission. In the present study, we found that 2-cyano-3,12-dioxo-oleana-1,9(11)-dien-28-oic acid methyl ester (CDDO-Me) attenuated CA1 neuronal death and aberrant mitochondrial elongations in these neurons coupled with enhanced RalBP1 expression and reduced 4-HNE levels following status epilepticus (SE). RalBP1 knockdown did not affect mitochondrial dynamics and CA1 neuronal death under physiological and post-SE conditions. Following SE, however, cotreatment of RalBP1 siRNA diminished the effect of CDDO-Me on 4-HNE levels, mitochondrial hyperfusion in CA1 neurons, and CA1 neuronal death. These findings indicate that CDDO-Me may ameliorate CA1 neuronal death by facilitating RalBP1-mediated 4-HNE efflux and mitochondrial fission following SE. Therefore, our findings suggest that increased RalBP1 expression/activity may be one of the considerable targets to protect neurons from SE.

Rlip Depletion Alters Oncogene Transcription at Multiple Distinct Regulatory Levels

Simple Summary

Rlip76 is a multifunctional membrane protein that facilitates cancer growth, and its depletion kills cancer cells. We recently found that Rlip depletion also results in broad changes to oncogene and tumor suppressor transcription. The present studies were designed to decipher the unknown downstream signaling pathways and transcriptional regulatory mechanisms driving the effect. Building on prior findings that Rlip depletion induces broad methylomic changes, we found using bioluminescence reporter assays that depletion of Rlip also exerts transcriptional control over several cancer genes through methylation-independent changes in transcription factor-mediated activation of their promoter regions and through additional as yet unidentified mechanisms. These findings have important implications for Rlip-targeted cancer therapy.

Abstract

Rlip76 (Rlip) is a multifunctional membrane protein that facilitates the high metabolic rates of cancer cells through the efflux of toxic metabolites and other functions. Rlip inhibition or depletion results in broad-spectrum anti-cancer effects in vitro and in vivo. Rlip depletion effectively suppresses malignancy and causes global reversion of characteristic CpG island methylomic and transcriptomic aberrations in the p53-null mouse model of spontaneous carcinogenesis through incompletely defined signaling and transcriptomic mechanisms. The methylome and transcriptome are normally regulated by the concerted actions of several mechanisms that include chromatin remodeling, promoter methylation, transcription factor interactions, and miRNAs. The present studies investigated the interaction of Rlip depletion or inhibition with the promoter methylation and transcription of selected cancer-related genes identified as being affected by Rlip depletion in our previous studies. We constructed novel promoter CpG island/luciferase reporter plasmids that respond only to CpG methylation and transcription factors. We found that Rlip depletion regulated expression by a transcription factor-based mechanism that functioned independently of promoter CpG methylation, lipid peroxidation, and p53 status.

Transcriptional and Epigenetic Response to Sedentary Behavior and Physical Activity in Children and Adolescents: A Systematic Review

BACKGROUND

The links of sedentary behavior and physical activity with health outcomes in children and adolescents is well known. However, the molecular mechanisms involved are poorly understood. We aimed to synthesize the current knowledge of the association of sedentary behavior and physical activity (acute and chronic effects) with gene expression and epigenetic modifications in children and adolescents.

METHODS

PubMed, Web of Science, and Scopus databases were systematically searched until April 2022. A total of 15 articles were eligible for this review. The risk of bias assessment was performed using the Joanna Briggs Institute Critical Appraisal Tool for Systematic Reviews and/or a modified version of the Downs and Black checklist.

RESULTS

Thirteen studies used candidate gene approach, while only 2 studies performed high-throughput analyses. The candidate genes significantly linked to sedentary behavior or physical activity were: FOXP3, HSD11B2, IL-10, TNF-α, ADRB2, VEGF, HSP70, SOX, and GPX. Non-coding Ribonucleic acids (RNAs) regulated by sedentary behavior or physical activity were: miRNA-222, miRNA-146^a, miRNA-16, miRNA-126, miR-320^a, and long non-coding RNA MALAT1. These molecules are involved in inflammation, immune function, angiogenic process, and cardiovascular disease. Transcriptomics analyses detected thousands of genes that were altered following an acute bout of physical activity and are linked to gene pathways related to immune function, apoptosis, and metabolic diseases.

CONCLUSION

The evidence found to date is rather limited. Multidisciplinary studies are essential to characterize the molecular mechanisms in response to sedentary behavior and physical activity in the pediatric population. Larger cohorts and randomized controlled trials, in combination with multi-omics analyses, may provide the necessary data to bring the field forward.

SYSTEMATIC REVIEW REGISTRATION

[www.ClinicalTrials.gov], identifier [CRD42021235431].

The epigenetic landscape of exercise in cardiac health and disease

With the rising incidence of cardiovascular diseases, the concomitant mortality and morbidity impose huge burdens on quality of life and societal costs. It is generally accepted that physical inactivity is one of the major risk factors for cardiac disease and that exercise benefits the heart in both physiological and pathologic conditions. However, the molecular mechanisms governing the cardioprotective effects exerted by exercise remain incompletely understood. Most recently, an increasing number of studies indicate the involvement of epigenetic modifications in the promotion of cardiac health and prevention of cardiac disease. Exercise and other lifestyle factors extensively induce epigenetic modifications, including DNA/RNA methylation, histone post-translational modifications, and non-coding RNAs in multiple tissues, which may contribute to their positive effects in human health and diseases. In addition, several studies have shown that maternal or paternal exercise prevents age-associated or high-fat diet-induced metabolic dysfunction in the offspring, reinforcing the importance of epigenetics in mediating the beneficial effects of exercise. It has been shown that exercise can directly modify cardiac epigenetics to promote cardiac health and protect the heart against various pathological processes, or it can modify epigenetics in other tissues, which reduces the risk of cardiac disease and affords cardioprotection through exerkines. An in-depth understanding of the epigenetic landscape of cardioprotective response to exercise will provide new therapeutic targets for cardiac diseases. This review, therefore, aimed to acquaint the cardiac community with the rapidly advancing and evolving field of exercise and epigenetics.

Haploinsufficiency Interactions between RALBP1 and p53 in ERBB2 and PyVT Models of Mouse Mammary Carcinogenesis

Simple Summary

Rlip knockout has been reported to prevent cancer in highly cancer-susceptible mice lacking p53, and Rlip knockdown kills many types of cancer cells. In humans, breast cancer shows diverse characteristics, including HER2-driven subtypes and viral-driven subtypes. HER2 can be targeted; however, escape of the cancer from targeted therapies remains a problem. In this work we evaluated the capacity of Rlip knockout to prevent breast cancer in genetically engineered mouse models of HER2-driven breast cancer (Erbb2 model) and polyomavirus-driven breast cancer (PyVT model). We found that in Erbb2 mice, Rlip knockout significantly delayed oncogenesis and reduced the expression of genes associated with poor prognosis in patients. In PyVT mice, Rlip knockout did not delay oncogenesis or tumor growth, but Rlip knockdown reduced tumor metastasis to the lung. We conclude that Rlip inhibitors may significantly improve survival in HER2-positive patients, but are unlikely to offer benefits to patients with polyomavirus-associated tumors.

Abstract

We recently reported that loss of one or both alleles of Ralbp1, which encodes the stress-protective protein RLIP76 (Rlip), exerts a strong dominant negative effect on both the inherent cancer susceptibility and the chemically inducible cancer susceptibility of mice lacking one or both alleles of the tumor suppressor p53. In this paper, we examined whether congenital Rlip deficiency could prevent genetically-driven breast cancer in two transgenic mouse models: the MMTV-PyVT model, which expresses the polyomavirus middle T antigen (PyVT) under control of the mouse mammary tumor virus promoter (MMTV) and the MMTV-Erbb2 model which expresses MMTV-driven erythroblastic leukemia viral oncogene homolog 2 (Erbb2, HER2/Neu) and frequently acquires p53 mutations. We found that loss of either one or two Rlip alleles had a suppressive effect on carcinogenesis in Erbb2 over-expressing mice. Interestingly, Rlip deficiency did not affect tumor growth but significantly reduced the lung metastatic burden of breast cancer in the viral PyVT model, which does not depend on either Ras or loss of p53. Furthermore, spontaneous tumors of MMTV-PyVT/Rlip+/+ mice showed no regression following Rlip knockdown. Finally, mice lacking one or both Rlip alleles differentially expressed markers for apoptotic signaling, proliferation, angiogenesis, and cell cycling in PyVT and Erbb2 breast tumors. Our results support the efficacy of Rlip depletion in suppressing p53 inactivated cancers, and our findings may yield novel methods for prevention or treatment of cancer in patients with HER2 mutations or tumor HER2 expression.

Targeting the mercapturic acid pathway for the treatment of melanoma

The treatment of metastatic melanoma is greatly hampered by the simultaneous dysregulation of several major signaling pathways that suppress apoptosis and promote its growth and invasion. The global resistance of melanomas to therapeutics is also supported by a highly active mercapturic acid pathway (MAP), which is responsible for the metabolism and excretion of numerous chemotherapy agents. The relative importance of the MAP in melanoma survival was not recognized until demonstrated that B16 melanoma undergoes dramatic apoptosis and regression upon the depletion or inhibition of the MAP transporter protein RLIP. RLIP is a multi-functional protein that couples ATP hydrolysis with the movement of substances. As the rate-limiting step of the MAP, the primary function of RLIP in the plasma membrane is to catalyze the ATP-dependent efflux of unmetabolized drugs and toxins, including glutathione (GSH) conjugates of electrophilic toxins (GS-Es), which are the precursors of mercapturic acids. Clathrin-dependent endocytosis (CDE) is an essential mechanism for internalizing ligand-receptor complexes that promote tumor cell proliferation through autocrine stimulation (Wnt5a, PDGF, βFGF, TNFα) or paracrine stimulation by hormones produced by fibroblasts (IGF1, HGF) or inflammatory cells (IL8). Aberrant functioning of these pathways appears critical for melanoma cell invasion, metastasis, and evasion of apoptosis. This review focuses on the selective depletion or inhibition of RLIP as a highly effective targeted therapy for melanoma that could cause the simultaneous disruption of the MAP and critical peptide hormone signaling that relies on CDE.

Prevention of mammary carcinogenesis in MMTV-neu mice by targeting RLIP

The overexpression and amplification of the protooncogene neu (ERBB2) play an important role in the development of aggressive breast cancer (BC) in humans. Ral-interacting protein (RLIP), a modular stress-response protein with pleiotropic functions, is overexpressed in several types of cancer, including BC. Here, we show that blocking RLIP attenuates the deleterious effects caused by the loss of the tumor suppressor p53 and inhibits the growth of human BC both in vitro and in vivo in MMTV-neu mice. In addition, we show that treatment with the diet-derived, RLIP-targeting chemotherapeutic 2'-hydroxyflavanone (2HF), alone or in combination with RLIP-specific antisense RNA or antibodies, significantly reduced the cumulative incidence and/or burden of mammary hyperplasia and carcinoma in MMTV-neu mice. 2HF treatment correlated with reduced tumor cell proliferation and increased apoptosis, and the average number of Ki67-positive (proliferating) cells was significantly lower in the tumors of 2HF-treated mice than in the tumors of control mice. Furthermore, targeting RLIP also resulted in the overexpression of E-cadherin and the infiltration of CD3+ T cells into mammary tumors. Taken together, these results underscore the translational potential of RLIP-targeting agents and provide a strong rationale to validate them in the clinic.

Activating p53 function by targeting RLIP

Aberrations in RLIP, p53, and PKCα represent essentially the entire spectrum of all human neoplasms. Elevated PKCα expression, failure of the cell cycle checkpoint (p53 dysfunction), and abnormal glutathione (GSH) metabolism are fundamental hallmarks of carcinogenesis and drug/radiation resistance. However, a lack of investigations into the interactions between these important regulatory nodes has fundamentally limited our understanding of carcinogenesis and the development of effective interventions for cancer prevention and therapy. Loss of p53, perhaps the most powerful tumor suppressor gene, predisposes rodents to spontaneous cancer and humans to familial, as well as acquired, cancers. Until recently, no genetic manipulation of any oncogene had been reported to abrogate spontaneous carcinogenesis in p53^-/- rodent models. However, the overexpression of RLIP, a GSH-electrophile conjugate (GS-E) transporter, has been found to enhance cancer cell proliferation and confer drug/radiation resistance, whereas its depletion causes tumor regression, suggesting its importance in cancer and drug/radiation resistance. Indeed, RLIP is an essential effector of p53 that is necessary for broad cancer-promoting epigenetic remodeling. Interestingly, through a haploinsufficiency mechanism, the partial depletion of RLIP in p53^-/- mice provides complete protection from neoplasia. Furthermore, RLIP^-/- mice exhibit altered p53 and PKCα function, marked deficiency in clathrin-dependent endocytosis (CDE), and almost total resistance to chemical carcinogenesis. Based on these findings, in this review, we present a novel and radical hypothesis that expands our understanding of the highly significant cross-talk between p53, PKCα, and GSH signaling by RLIP in multiple tumor models.

Rlip Depletion Suppresses Growth of Breast Cancer

RLIP76 (RAL-binding protein-1, Rlip) is a stress-protective mercapturic-acid-pathway transporter protein that also plays a key role in regulating clathrin-dependent endocytosis as a Ral effector. Targeted inhibition or depletion of Rlip causes regression of xenografts of many cancers and is capable of abrogating tumor formation in p53-null mice. This is associated with the reversion of the abnormal methylomic profile of p53-null mice to wild-type. In a query of The Cancer Genome Atlas (TCGA) databases, we found that Rlip expression was associated with poor survival and with significant differences in the frequencies of PIK3CA mutation, MYC amplification, and CDKN2A/B deletion, which were the most commonly mutated, amplified, and deleted genes, respectively, among TCGA breast cancer patients. We conducted the present study to further examine the effects of Rlip inhibition and to evaluate the in vitro and in vivo efficacy in breast cancer. Using immunogold electron microscopy, we found that plasma-membrane Rlip was accessible to cell-surface antibodies in the MCF7 (ER+) breast cancer cell line. Rlip depletion resulted in decreased survival of MCF7 and MDA-MB-231 cells and increased terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positivity and DNA laddering, indicating apoptotic cell death. Additionally, in vitro knockdown of Rlip inhibited EGF endocytosis and WNT/MAPK signaling. Xenograft studies in nude mice showed regression of breast cancer via antisense-mediated depletion of Rlip mRNA as well as by anti-Rlip antibody. Finally, knockdown of Rlip by antisense locked nucleic acid oligonucleotides increased markers for apoptotic signaling and decreased markers for proliferation, angiogenesis, and cell cycling in MCF7 and MDA-MB-231luc xenografts. Our findings validate Rlip as an attractive target in breast cancer.

Topical 2'-Hydroxyflavanone for Cutaneous Melanoma

2′-hydroxyflavanone (2HF) is a dietary flavonoid with anticancer activity towards multiple cancers. Here, we report that topically applied 2HF inhibits the growth of intradermal implants of melanoma in immunocompetent mice. 2HF induced apoptosis and inhibited the growth of the human SK-MEL-24 as well as murine B16-F0 and B16-F10 melanoma cell lines in vitro. Apoptosis was associated with depletion of caspase-3, caspase-9, and PARP1 in B16-F0 and SK-MEL-24 cells. Caspase-9 and MEKK-15 were undetected even in untreated B16-F10 cells. Signaling proteins TNFα, and phospho-PDGFR-β were depleted in all three cell lines; MEKK-15 was depleted by 2HF in SK-MEL-24 cells. 2HF enhanced sunitinib (an MEK and PDGFR-β inhibitor) and AZD 2461 (a PARP1 inhibitor) cytotoxicity. 2HF also depleted the Ral-regulated, stress-responsive, antiapoptotic endocytic protein RLIP76 (RALBP1), the inhibition of which has previously been shown to inhibit B16-F0 melanoma growth in vivo. Functional inhibition of RLIP76 was evident from inhibition of epidermal growth factor (EGF) endocytosis by 2HF. We found that topically applied 2HF–Pluronic Lecithin Organogel (PLO) gel inhibited B16-F0 and B16-F10 tumors implanted in mice and caused no overt toxicity despite significant systemic absorption. 2HF treatment reduced phospho-AKT, vimentin, fibronectin, CDK4, cyclinB1, and BCL2, whereas it increased BIM and phospho-AMPK in excised tumors. Several cancer signals are controlled by endocytosis, a process strongly inhibited by RLIP76 depletion. We conclude that 2HF–PLO gel may be useful for topical therapy of cutaneous metastases of melanoma and could enhance the antineoplastic effects of sunitinib and PARP1 inhibitors. The mechanism of action of 2HF in melanoma overlaps with RLI76 inhibitors.

Synergistic efficacy of RLIP inhibition and 2'-hydroxyflavanone against DMBA-induced mammary carcinogenesis in SENCAR mice

Substantial evidence suggests that 7,12-dimethylbenzanthracene (DMBA)-induced mammary carcinogenesis in mice mimics human breast cancer (BC) in many respects. Therefore, it has been used extensively to evaluate preventive and therapeutic agents for human BC. Mammary carcinogenesis induced by DMBA administration in female SENsitive to CARcinogen (SENCAR) mice was characterized by histopathological analysis of the mammary glands and alterations to the phosphatidylinositol 3-kinase/protein kinase B/cyclin-dependent kinase 1 (PI3K/Akt/CDK1) pathway. We recently reported that 2'-hydroxyflavanone (2HF) is a promising diet-derived chemotherapeutic agent that suppresses BC growth in vitro and in vivo by targeting a 76 kDa ral-interacting protein (RLIP). The objective of the current study was to investigate the synergistic anticarcinogenic effects of RLIP inhibition/depletion and 2HF in an in vivo model of DMBA-induced mammary carcinogenesis in SENCAR mice. Mice were given 2HF (50 mg/kg, bw, orally on alternate days), RLIP antibody (Rab; 5 mg/kg, bw, ip weekly), RLIP antisense (RAS; 5 mg/kg, b.w., ip weekly), or a combination of 2HF + Rab + RAS. Animals were monitored daily, and 7 days after the first appearance of moribund behavior, tissues were harvested for morphological and immunohistological analysis. Western blot analyses were performed to determine the expression of anti- and proapoptotic proteins in the mammary glands. Our results reveal that 2HF, RAS, and Rab significantly prevented the carcinogenic effects of DMBA administration in the mammary glands and other organs. Further, mice treated with a combination of 2HF + RAS + Rab exhibited no carcinogenic effect of DMBA as compared to either or the single agent-treated mice. This study demonstrates for the first time the anticarcinogenic effects of 2HF and RLIP inhibition/depletion in vivo in a novel DMBA-induced model of BC in SENCAR mice and provides the rationale for further clinical investigation.

RLIP: An existential requirement for breast carcinogenesis

Breast cancer (BC) is the most common cancer among women worldwide. Due to its complexity in nature, effective BC treatment can encounter many challenges. The human RALBP1 gene encodes a 76-kDa splice variant protein, RLIP (ral-binding protein1, RalBP1), a stress-protective mercapturic acid pathway (MAP) transporter protein, that also plays a key role in regulating clathrin-dependent endocytosis (CDE) as a Ral effector. Growing evidence shows that targeting RLIP may be an effective strategy in cancer therapy, as RLIP is over-expressed in multiple cancers and is known to induce resistance to apoptosis and chemotherapeutic drugs. Recent studies demonstrated that RLIP is expressed in human BC tissues, as well as BC cell lines. Knockdown of RLIP resulted in apoptotic death of BC cells in vitro, and targeted inhibition and depletion of RLIP resulted in regression of BC in xenograft studies of nude mice. Signaling studies showed that RLIP depletion inhibited endocytosis and differentially regulated signaling to Akt, Myc, and ERK1/2. However, the proliferation and multi-specific transport mechanisms that promote RLIP-mediated cell death in BC are not well understood. In this review, we will discuss a missing but an essentially determining and connecting piece of the puzzle on the understanding of proliferation and transport mechanisms by focused analyses of the apoptotic, drug- and radiation-sensitivity regulated by RLIP, a stress-responsive non-ATP-binding cassette (ABC), high capacity MAP transporter, in breast cancer.

2'-Hydroxyflavanone inhibits in vitro and in vivo growth of breast cancer cells by targeting RLIP76

Consumption of citrus-fruits is associated with reduced incidence of breast cancer (BC), the most common cancer diagnosed in women across the globe. In this study, we investigated the anticancer potential of 2-Hydroxyflavanone (2HF) in BC. 2HF, a citrus-bioflavonoid, has demonstrated anticancer properties in various cancers, but its anticancer role in BC has not been well studied. We investigated the in vitro and in vivo growth inhibitory effects of 2HF in an array of BC lines and in xenograft mouse models of ER-positive and HER2-positive BC cells. Compared to control, 2HF treatment reduced cell viability and suppressed migratory and invasive potential of BC cells, while, no growth inhibitory effects were observed in non-tumorigenic breast epithelial cells. Further, 2HF inhibited the expression of RLIP76, a stress-defensive and anti-apoptotic protein, which is over-expressed in BC cells and simultaneously reduced proliferation of BC cells. Nude mice bearing MCF7 or SKBR3 BC cells xenografts treated with either 2HF or targeting RLIP76 by RLIP76-antisense or RLIP76-antibody treatment had significantly lower tumor-weight as compared to corresponding controls. In addition, Western-blotting and immunohistochemical analysis of tumor tissue from control and treatment group mice showed that 2HF decreased protein expression levels of RLIP76, and the decrease was similar to those seen following RLIP76-antisense treatment. Furthermore, 2HF decreased expression of Ki67, CD31, vimentin, inhibited phosphorylation of Akt and expression of survivin and Bcl2, and increased levels of Bax, E-cadherin, and cleaved-PARP. Therefore, our results indicate that 2HF may suppress BC growth in vitro and in vivo by targeting RLIP76, and may serve as a potential adjuvant treatment in BC patients.

2'-Hydroxyflavanone effectively targets RLIP76-mediated drug transport and regulates critical signaling networks in breast cancer

Breast cancer (BC) is the most common cancer in women. Estrogen, epidermal growth factor receptor 2 (ERBB2, HER2), and oxidative stress represent critical mechanistic nodes associated with BC. RLIP76 is a major mercapturic acid pathway transporter whose expression is increased in BC. In the quest of a novel molecule with chemopreventive and chemotherapeutic potential, we evaluated the effects of 2'-Hydroxyflavanone (2HF) in BC. 2HF enhanced the inhibitory effects of RLIP76 depletion and also inhibited RLIP76-mediated doxorubicin transport in BC cells. RNA-sequencing revealed that 2HF induces strong reversal of the gene expression pattern in ER⁺MCF7, HER2⁺ SKBR3 and triple-negative MDA-MB-231 BC cells with minimal effects on MCF10A normal breast epithelial cells. 2HF down regulated ERα and enhanced inhibitory effects of imatinib mesylate/Gleevec in MCF7 cells. 2HF also down regulated ERα and HER2 gene networks in MCF7 and SKBR3 cells, respectively. 2HF activated TP53 and inhibited TGFβ1 canonical pathway in MCF7 and MDA-MB-231 BC cells. 2HF also regulated the expression of a number of critical prognostic genes of MammaPrint panel and their upstream targets including TP53, CDKN2A and MYC. The collective findings from this study provide a comprehensive, direct and integrated evidence for the benefits of 2HF in targeting major and clinically relevant mechanistic regulators of BC.

Rlip depletion prevents spontaneous neoplasia in TP53 null mice

Mice that have homozygous deletion of the p53 tumor suppressor protein universally die of malignancy, generally before 6 months of age. We show that hemizygous deficiency of RALBP1 (RLIP76 or Rlip) confers a degree of protection from spontaneous malignancy that has never previously been observed. This discovery introduces a paradigm for p53 function, in which Rlip plays a central role as an effector that appears necessary for the cancer susceptibility of p53 null mice. Because p53 loss has a powerful effect on genomic instability that contributes to the initiation and promotion of cancers and to drug and radiation resistance in humans, our findings provide a method for prevention and therapy of p53-deficient cancer.

TP53 (p53) is a tumor suppressor whose functions are lost or altered in most malignancies. p53 homozygous knockout (p53^−/−) mice uniformly die of spontaneous malignancy, typically T-cell lymphoma. RALBP1 (RLIP76, Rlip) is a stress-protective, mercapturic acid pathway transporter protein that also functions as a Ral effector involved in clathrin-dependent endocytosis. In stark contrast to p53^−/− mice, Rlip^−/− mice are highly resistant to carcinogenesis. We report here that partial Rlip deficiency induced by weekly administration of an Rlip-specific phosphorothioate antisense oligonucleotide, R508, strongly inhibited spontaneous as well as benzo(a)pyrene-induced carcinogenesis in p53^−/− mice. This treatment effectively prevented large-scale methylomic and transcriptomic abnormalities suggestive of inflammation found in cancer-bearing p53^−/− mice. The remarkable efficiency with which Rlip deficiency suppresses spontaneous malignancy in p53^−/− mice has not been observed with any previously reported pharmacologic or genetic intervention. These findings are supported by cross-breeding experiments demonstrating that hemizygous Rlip deficiency also reduces the spontaneous malignancy phenotype of p53^+/− mice. Rlip is found on the cell surface, and antibodies directed against Rlip were found to inhibit growth and promote apoptosis of cell lines as effectively as Rlip siRNA. The work presented here investigates several features, including oxidative DNA damage of the Rlip–p53 association in malignant transformation, and offers a paradigm for the mechanisms of tumor suppression by p53 and the prospects of suppressing spontaneous malignancy in hereditary cancer syndromes such as Li-Fraumeni.

Ral signaling pathway in health and cancer

The Ral (Ras-Like) signaling pathway plays an important role in the biology of cells. A plethora of effects is regulated by this signaling pathway and its prooncogenic effectors. Our team has demonstrated the overactivation of the RalA signaling pathway in a number of human malignancies including cancers of the liver, ovary, lung, brain, and malignant peripheral nerve sheath tumors. Additionally, we have shown that the activation of RalA in cancer stem cells is higher in comparison with differentiated cancer cells. In this article, we review the role of Ral signaling in health and disease with a focus on the role of this multifunctional protein in the generation of therapies for cancer. An improved understanding of this pathway can lead to development of a novel class of anticancer therapies that functions on the basis of intervention with RalA or its downstream effectors.

Cardiometabolic risk markers, adipocyte fatty acid binding protein (aFABP) and the impact of high-intensity interval training (HIIT) in obese adolescents

OBJECTIVE

The impact of high-intensity interval training (HIIT) as well as the association between the adipocyte fatty binding protein (aFABP) and cardiometabolic risk factors in overweight adolescents was investigated.

METHODS

Twenty-eight adolescents (13-18years; BMI≥90th percentile according to German reference values) were offered HIIT twice weekly for 6months. At baseline and after program completion, anthropometric, clinical and metabolic characteristics were assessed and a fasting blood sample was obtained. Leptin, adiponectin, visfatin and aFABP were measured using commercially available kits. DNA methylation at RALBP1 was assessed using pyrosequencing. Descriptive statistics, Pearson's correlation and linear models were calculated.

RESULTS

Mean age at start of the program was 15.5±1.4years (53.5% females) and 20/28 (71%) provided follow-up data. At baseline, aFABP was correlated with BMI-SDS (0.48 [0.13,0.72]; p=0.0095), waist-to-height-ratio (0.63 [0.33,0.81], p=0.00036) and body fat content (0.55 [0.21, 0.77]; p=0.0031). Certain markers of metabolic risk were significantly correlated with aFABP (HOMA-IR 0.52 [0.19, 0.75], p=0.0044; γGT 0.48 [0.13, 0.73], p=0.0091; uric acid 0.46 [0.11, 0.71] p=0.013; HDL-C -0.39 [-0.66, -0.01] p=0.043; triglycerides 0.38 [0.01, 0.66], p=0.047). With the exception of triglycerides, these associations vanished after adjusting for BMI-SDS. aFABP did not depend on sex, age or pubertal stage in obese adolescents. After the HIIT program, small but significant reductions were observed in waist-to-height-ratio, (0.013 [0.0025, 0.024]; p=0.023), skin-fold based body fat content (2.0% [0.6, 3.5]; p=0.011), and standard deviation score of systolic blood pressure (0.69 [0.26 to 1.1]; p=0.0036). No changes were observed in adipokines or epigenetic markers following the program.

CONCLUSION

HIIT may have beneficial effects on body composition and cardiometabolic health in overweight adolescents. Like in adults, aFABP seems to be associated with markers of metabolic risk in obese adolescents.

Diarylheptanoids Rich Fraction of Alnus nepalensis Attenuates Malaria Pathogenesis: In-vitro and In-vivo Study

Diarylheptanoids from Alnus nepalensis leaves have been reported for promising activity against filariasis, a mosquito-borne disease, and this has prompted us to investigate its anti-malarial and safety profile using in-vitro and in-vivo bioassays. A. nepalensis leaf extracts were tested in-vitro against chloroquine-sensitive Plasmodium falciparum NF54 by measuring the parasite specific lactate dehydrogenase activity. Among all, the chloroform extract (ANC) has shown promising anti-plasmodial activity (IC50 8.06 ± 0.26 µg/mL). HPLC analysis of ANC showed the presence of diarylheptanoids. Efficacy and safety of ANC were further validated in in-vivo system using Plasmodium berghei-induced malaria model and acute oral toxicity in mice. Malaria was induced by intra-peritoneal injection of P. berghei infected red blood cells to the female Balb/c mice. ANC was administered orally at doses of 100 and 300 mg/kg/day following Peter's 4 day suppression test. Oral administration of ANC showed significant reduction of parasitaemia and increase in mean survival time. It also attributed to inhibition of the parasite induced pro-inflammatory cytokines as well as afford to significant increase in the blood glucose and haemoglobin level when compared with vehicle-treated infected mice. In-vivo safety evaluation study revealed that ANC is non-toxic at higher concentration. Copyright © 2016 John Wiley & Sons, Ltd.

DNA methylation as a diagnostic and therapeutic target in the battle against Type 2 diabetes

Type 2 diabetes (T2D) develops due to insulin resistance and impaired insulin secretion, predominantly in genetically predisposed subjects exposed to nongenetic risk factors like obesity, physical inactivity and ageing. Emerging data suggest that epigenetics also play a key role in the pathogenesis of T2D. Genome-wide studies have identified altered DNA methylation patterns in pancreatic islets, skeletal muscle and adipose tissue from subjects with T2D compared with nondiabetic controls. Environmental factors known to affect T2D, including obesity, exercise and diet, have also been found to alter the human epigenome. Additionally, ageing and the intrauterine environment are associated with differential DNA methylation. Together, these data highlight a key role for epigenetics and particularly DNA methylation in the growing incidence of T2D.

Mining the genome for lipid genes

Mining of the genome for lipid genes has since the early 1970s helped to shape our understanding of how triglycerides are packaged (in chylomicrons), repackaged (in very low density lipoproteins; VLDL), and hydrolyzed, and also how remnant and low-density lipoproteins (LDL) are cleared from the circulation. Gene discoveries have also provided insights into high-density lipoprotein (HDL) biogenesis and remodeling. Interestingly, at least half of these key molecular genetic studies were initiated with the benefit of prior knowledge of relevant proteins. In addition, multiple important findings originated from studies in mouse, and from other types of non-genetic approaches. Although it appears by now that the main lipid pathways have been uncovered, and that only modulators or adaptor proteins such as those encoded by LDLRAP1, APOA5, ANGPLT3/4, and PCSK9 are currently being discovered, genome wide association studies (GWAS) in particular have implicated many new loci based on statistical analyses; these may prove to have equally large impacts on lipoprotein traits as gene products that are already known. On the other hand, since 2004 - and particularly since 2010 when massively parallel sequencing has become de rigeur - no major new insights into genes governing lipid metabolism have been reported. This is probably because the etiologies of true Mendelian lipid disorders with overt clinical complications have been largely resolved. In the meantime, it has become clear that proving the importance of new candidate genes is challenging. This could be due to very low frequencies of large impact variants in the population. It must further be emphasized that functional genetic studies, while necessary, are often difficult to accomplish, making it hazardous to upgrade a variant that is simply associated to being definitively causative. Also, it is clear that applying a monogenic approach to dissect complex lipid traits that are mostly of polygenic origin is the wrong way to proceed. The hope is that large-scale data acquisition combined with sophisticated computerized analyses will help to prioritize and select the most promising candidate genes for future research. We suggest that at this point in time, investment in sequence technology driven candidate gene discovery could be recalibrated by refocusing efforts on direct functional analysis of the genes that have already been discovered. This article is part of a Special Issue entitled: From Genome to Function.

Epigenetic adaptation to regular exercise in humans

Regular exercise has numerous health benefits, for example, it reduces the risk of cardiovascular disease and cancer. It has also been shown that the risk of type 2 diabetes can be halved in high-risk groups through nonpharmacological lifestyle interventions involving exercise and diet. Nevertheless, the number of people living a sedentary life is dramatically increasing worldwide. Researchers have searched for molecular mechanisms explaining the health benefits of regular exercise for decades and it is well established that exercise alters the gene expression pattern in multiple tissues. However, until recently it was unknown that regular exercise can modify the genome-wide DNA methylation pattern in humans. This review will focus on recent progress in the field of regular exercise and epigenetics.

Glutathionylated lipid aldehydes are products of adipocyte oxidative stress and activators of macrophage inflammation

Obesity-induced insulin resistance has been linked to adipose tissue lipid aldehyde production and protein carbonylation. Trans-4-hydroxy-2-nonenal (4-HNE) is the most abundant lipid aldehyde in murine adipose tissue and is metabolized by glutathione S-transferase A4 (GSTA4), producing glutathionyl-HNE (GS-HNE) and its metabolite glutathionyl-1,4-dihydroxynonene (GS-DHN). The objective of this study was to evaluate adipocyte production of GS-HNE and GS-DHN and their effect on macrophage inflammation. Compared with lean controls, GS-HNE and GS-DHN were more abundant in visceral adipose tissue of ob/ob mice and diet-induced obese, insulin-resistant mice. High glucose and oxidative stress induced production of GS-HNE and GS-DHN by 3T3-L1 adipocytes in a GSTA4-dependent manner, and both glutathionylated metabolites induced secretion of tumor necrosis factor-α from RAW 264.7 and primary peritoneal macrophages. Targeted microarray analysis revealed GS-HNE and GS-DHN induced expression of inflammatory genes, including C3, C4b, c-Fos, igtb2, Nfkb1, and Nos2. Transgenic overexpression of GSTA4 in mouse adipose tissue led to increased production of GS-HNE associated with higher fasting glucose levels and moderately impaired glucose tolerance. These results indicated adipocyte oxidative stress results in GSTA4-dependent production of proinflammatory glutathione metabolites, GS-HNE and GS-DHN, which may represent a novel mechanism by which adipocyte dysfunction results in tissue inflammation and insulin resistance.

Antimalarial and safety evaluation of Pluchea lanceolata (DC.) Oliv. & Hiern: in-vitro and in-vivo study

ETHNOPHARMACOLOGICAL RELEVANCE

Many of the effective therapeutic strategies have been derived from ethnopharmacologically used natural products. Pluchea lanceolata is an herb employed in Indian folk medicine for malaria like fever but it lacks proper pharmacological intervention.

AIM OF THE STUDY

To evaluate antimalarial and safety profile of Pluchea lanceolata: an in-vitro, in-vivo for its ethnopharmacological validation.

MATERIALS AND METHODS

Methanol, butanol, ethyl acetate, chloroform, hexane extracts and its isolate, taraxasterol acetate (TxAc) were obtained from air dried aerial part of Pluchea lanceolata. These were tested in-vitro against chloroquine-sensitive strain of Plasmodium falciparum NF54 by measuring the parasite specific lactate dehydrogenase activity. The most potent hexane extract and TxAc were further validated for in-vivo antimalarial and safety evaluation. TxAc, a pentacyclic-triterpene isolated from the most active fraction was further evaluated with special emphasis on inflammatory mediators involved in malaria pathogenesis. Murine malaria was induced by intra-peritoneal injection of Plasmodium berghei infected red blood cells to the male Swiss inbred mice. Mice were orally treated following Peters 4-Day suppression test. In-vivo antimalarial efficacy was examined by evaluating the parasitaemia, percent survival, mean survival time, blood glucose, haemoglobin and pro-inflammatory mediators involved in malaria pathogenesis.

RESULTS

Hexane extract and TxAc showed promising antimalarial activity in-vitro and in-vivo condition. TxAc attributed in inhibition of the pro-inflammatory cytokines as well as afford to significant increase in the blood glucose and haemoglobin level when compared with vehicle treated infected mice. We have not observed the synergistic action of combinations of chloroquine and TxAc from our experimental results. In-vitro and in-vivo safety evaluation study revealed that hexane extract is non toxic at higher concentration.

CONCLUSION

Present study further validates the ancient Indian traditional knowledge and use of Pluchea lanceolata as an antimalarial agent. Study confirms the suitability of Pluchea lanceolata as a candidate for further studies to obtain a prototype for antimalarial medicine.

In vivo fluorescence-mediated tomography imaging demonstrates atorvastatin-mediated reduction of lesion macrophages in ApoE-/- mice

BACKGROUND

Macrophage recruitment into atherosclerotic plaques drives lesion progression, destabilization, and rupture. Chronic statin treatment reduces macrophage plaque content. Information on dynamics of macrophage recruitment would help assessing plaque vulnerability and guiding therapy. Techniques to image macrophage homing to vulnerable plaques in vivo are scarcely available. The authors tested if noninvasive fluorescence-mediated tomography (FMT) can assess plaque-stabilizing effects of short-term high-dosage atorvastatin.

METHODS

Macrophages from green-fluorescent-protein-transgenic mice were labeled with a near-infrared fluorescent dye and were injected IV in apolipoprotein E-deficient mice (n=9) on Western diet 7 days after guidewire-injury of the carotid artery. FMT-scans, 2 and 7 days thereafter, quantified macrophage recruitment into carotid artery plaques. Atorvastatin was tested for macrophage adhesion, proliferation, and viability (n=5 to 6) in vitro. Fourteen mice received atorvastatin or vehicle for 4 days after 16 weeks on Western diet. FMT assessed macrophage recruitment into aortic and innominate artery lesions. Means (±SD)% are reported.

RESULTS

Double-labeled macrophages were recruited into carotid artery lesions. FMT resolved fluorescence projecting on the injured carotid artery and detected a signal increase to 300% (±191) after guidewire injury. Atorvastatin reduced macrophage adhesion to activated endothelial cells by 36% (±19). In a clinically relevant proof-of-concept intervention, FMT-imaging detected that 4 days atorvastatin treatment reduced macrophage recruitment by 57% (±8) indicating plaque stabilization. Immunohistochemistry confirmed reduced macrophage infiltration.

CONCLUSIONS

FMT optical imaging proved its high potential for clinical applicability for tracking recruitment of near-infrared fluorescent-labeled macrophages to vulnerable plaques in vivo. FMT-based quantification of macrophage recruitment demonstrated rapid plaque stabilization by 4-day atorvastatin treatment in apolipoprotein E-deficient mice.

Treating influenza with statins and other immunomodulatory agents

Statins not only reduce levels of LDL-cholesterol, they counteract the inflammatory changes associated with acute coronary syndrome and improve survival. Similarly, in patients hospitalized with laboratory-confirmed seasonal influenza, statin treatment is associated with a 41% reduction in 30-day mortality. Most patients of any age who are at increased risk of influenza mortality have chronic low-grade inflammation characteristic of metabolic syndrome. Moreover, differences in the immune responses of children and adults seem responsible for the low mortality in children and high mortality in adults seen in the 1918 influenza pandemic and in other acute infectious and non-infectious conditions. These differences probably reflect human evolutionary development. Thus the host response to influenza seems to be the major determinant of outcome. Outpatient statins are associated with reductions in hospitalizations and deaths due to sepsis and pneumonia. Inpatient statins are also associated with reductions in short-term pneumonia mortality. Other immunomodulatory agents--ACE inhibitors (ACEIs), angiotensin receptor blockers (ARBs), PPARγ and PPARα agonists (glitazones and fibrates) and AMPK agonists (metformin)--also reduce mortality in patients with pneumonia (ACEIs, ARBs) or in mouse models of influenza (PPAR and AMPK agonists). In experimental studies, treatment has not increased virus replication. Thus effective management of influenza may not always require targeting the virus with vaccines or antiviral agents. Clinical investigators, not systems biologists, have been the first to suggest that immunomodulatory agents might be used to treat influenza patients, but randomized controlled trials will be needed to provide convincing evidence that they work. To guide the choice of which agent(s) to study, we need new types of laboratory research in animal models and clinical and epidemiological research in patients with critical illness. These studies will have crucial implications for global public health. During the 2009 H1N1 influenza pandemic, timely and affordable supplies of vaccines and antiviral agents were unavailable to more than 90% of the world's people. In contrast, statins and other immunomodulatory agents are currently produced as inexpensive generics, global supplies are huge, and they would be available to treat patients in any country with a basic health care system on the first pandemic day. Treatment with statins and other immunomodulatory agents represents a new approach to reducing mortality caused by seasonal and pandemic influenza.

RLIP76 protein knockdown attenuates obesity due to a high-fat diet

Feeding a Western high-fat diet (HFD) to C57BL/6 mice induces obesity, associated with a chronic inflammatory state, lipid transport, and metabolic derangements, and organ system effects that particularly prominent in the kidneys. Here, we report that RLIP76 homozygous knock-out (RLIP76(-/-)) mice are highly resistant to obesity as well as these other features of metabolic syndrome caused by HFD. The normal increase in pro-inflammatory and fibrotic markers associated with HFD induced obesity in wild-type C57B mice was broadly and nearly completely abrogated in RLIP76(-/-) mice. This is a particularly striking finding because chemical markers of oxidative stress including lipid hydroperoxides and alkenals were significantly higher in RLIP76(-/-) mice. Whereas HFD caused marked suppression of AMPK in wild-type C57B mice, RLIP76(-/-) mice had baseline activation of AMP-activated protein kinase, which was not further affected by HFD. The baseline renal function was reduced in RLIP76(-/-) mice as compared with wild-type, but was unaffected by HFD, in marked contrast to severe renal impairment and glomerulopathy in the wild-type mice given HFD. Our findings confirm a fundamental role of RLIP76 in regulating the function of obesity-promoting pro-inflammatory cytokines, and provide a novel mechanism for targeted therapy of obesity and metabolic syndrome.

A six months exercise intervention influences the genome-wide DNA methylation pattern in human adipose tissue

Epigenetic mechanisms are implicated in gene regulation and the development of different diseases. The epigenome differs between cell types and has until now only been characterized for a few human tissues. Environmental factors potentially alter the epigenome. Here we describe the genome-wide pattern of DNA methylation in human adipose tissue from 23 healthy men, with a previous low level of physical activity, before and after a six months exercise intervention. We also investigate the differences in adipose tissue DNA methylation between 31 individuals with or without a family history of type 2 diabetes. DNA methylation was analyzed using Infinium HumanMethylation450 BeadChip, an array containing 485,577 probes covering 99% RefSeq genes. Global DNA methylation changed and 17,975 individual CpG sites in 7,663 unique genes showed altered levels of DNA methylation after the exercise intervention (q<0.05). Differential mRNA expression was present in 1/3 of gene regions with altered DNA methylation, including RALBP1, HDAC4 and NCOR2 (q<0.05). Using a luciferase assay, we could show that increased DNA methylation in vitro of the RALBP1 promoter suppressed the transcriptional activity (p = 0.03). Moreover, 18 obesity and 21 type 2 diabetes candidate genes had CpG sites with differences in adipose tissue DNA methylation in response to exercise (q<0.05), including TCF7L2 (6 CpG sites) and KCNQ1 (10 CpG sites). A simultaneous change in mRNA expression was seen for 6 of those genes. To understand if genes that exhibit differential DNA methylation and mRNA expression in human adipose tissue in vivo affect adipocyte metabolism, we silenced Hdac4 and Ncor2 respectively in 3T3-L1 adipocytes, which resulted in increased lipogenesis both in the basal and insulin stimulated state. In conclusion, exercise induces genome-wide changes in DNA methylation in human adipose tissue, potentially affecting adipocyte metabolism.

Effects of 4-hydroxynonenal on vascular endothelial and smooth muscle cell redox signaling and function in health and disease

4-hydroxynonenal (HNE) is a lipid hydroperoxide end product formed from the oxidation of n-6 polyunsaturated fatty acids. The relative abundance of HNE within the vasculature is dependent not only on the rate of lipid peroxidation and HNE synthesis but also on the removal of HNE adducts by phase II metabolic pathways such as glutathione-S-transferases. Depending on its relative concentration, HNE can induce a range of hormetic effects in vascular endothelial and smooth muscle cells, including kinase activation, proliferation, induction of phase II enzymes and in high doses inactivation of enzymatic processes and apoptosis. HNE also plays an important role in the pathogenesis of vascular diseases such as atherosclerosis, diabetes, neurodegenerative disorders and in utero diseases such as pre-eclampsia. This review examines the known production, metabolism and consequences of HNE synthesis within vascular endothelial and smooth muscle cells, highlighting alterations in mitochondrial and endoplasmic reticulum function and their association with various vascular pathologies.

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HNE is a lipid peroxidation endproduct regulating vascular redox signaling.

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HNE detoxification is tightly regulated in vascular and other cell types.

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Elevated HNE levels are associated with various vascular diseases.

P300 regulates the human RLIP76 promoter activity and gene expression

A 76-kDa Ral-interacting protein (RLIP76) has been implicated in the pathogenesis of cancer and diabetes. It is often over expressed in human malignant cell lines and human tumor samples and has been associated with metastasis and chemoresistance. RLIP76 homozygous knockout mice exhibit increased insulin sensitivity, hypoglycemia, and hypolipidemia, and resist cancer development. Little is known about the mechanism by which the expression of RLIP76 is regulated. In the present study, we functionally characterized the RLIP76 promoter using deletion mapping and mutational analysis to investigate the regulation of RLIP76 transcription. We have identified the promoter regions important for RLIP76 transcription, including a strong cis-activating element in the proximal promoter containing overlapping consensus cMYB and cETS binding sites. Transcription factor cMYB and the coactivator p300 associated with RLIP76 gene promoter as shown by CHIP assay. Knockdown of p300 in HEK293 cells reduced the activity of the promoter fragment containing wild type cMYB/cETS binding site in comparison to that with deleted or mutated cMYB/cETS binding site. Knockdown of p300 also decreased the RLIP76 expression as indicated by immunoblotting, immunocytochemistry and flow cytometry analysis. Thus, we report for the first time that p300 associates with the RLIP76 promoter via an overlapping cMYB and cETS binding site and regulates RLIP76 promoter activity and its expression.

The controversy over H5N1 transmissibility research: an opportunity to define a practical response to a global threat

Since December 2011, influenza virologists and biosecurity experts have been engaged in a controversial debate over research on the transmissibility of H5N1 influenza viruses. Influenza virologists disagreed with the NSABB's recommendation not to publish experimental details of their findings, whereas biosecurity experts wanted the details to be withheld and future research restricted. The virologists initially declared a voluntary moratorium on their work, but later the NSABB allowed their articles to be published, and soon transmissibility research will resume. Throughout the debate, both sides have had understandable views, but both have overlooked the more important question of whether anything could be done if one of these experimentally derived viruses or a naturally occurring and highly virulent influenza virus should emerge and cause a global pandemic. This is a crucial question, because during the 2009 H1N1 influenza pandemic, more than 90% of the world's people had no access to timely supplies of affordable vaccines and antiviral agents. Observational studies suggest that inpatient statin treatment reduces mortality in patients with laboratory-confirmed seasonal influenza. Other immunomodulatory agents (glitazones, fibrates and AMPK agonists) improve survival in mice infected with influenza viruses. These agents are produced as inexpensive generics in developing countries. If they were shown to be effective, they could be used immediately to treat patients in any country with a basic health care system. For this reason alone, influenza virologists and biosecurity experts need to join with public health officials to develop an agenda for laboratory and clinical research on these agents. This is the only approach that could yield practical measures for a global response to the next influenza pandemic.

Emerging treatments in lung cancer - targeting the RLIP76 molecular transporter

Multidrug resistance in lung cancer cells is a significant obstacle in the treatment of lung cancer. Resistance to chemotherapeutic agents is often the result of efflux of the drugs from cancer cells, mediated by adenosine triphosphate (ATP)-dependent drug transport across the plasma membrane. Thus, identifying molecular targets in the cancer cell transport machinery could be a key factor in successful combinatorial therapy, along with chemotherapeutic drugs. The transport protein Ral-interacting protein of 76 kDa (RLIP76), also known as Ral-binding protein 1 (RalBP1), is a highly promising target for lung cancer treatment. RLIP76 is an ATP-dependent non-ATP-binding cassette (ABC) transporter, responsible for the major transport function in many cells, including many cancer cell lines, causing efflux of glutathione-electrophile conjugates of both endogenous metabolites and environmental toxins. RLIP76 is expressed in most human tissues, and is overexpressed in non-small-cell lung cancer cell lines and in many tumor types. The blockade of RLIP76 by various approaches has been shown to increase the sensitivity to radiation and chemotherapeutic drugs, and leads to apoptosis in cells. In xenograft tumor models in mice, RLIP76 blockade or depletion results in complete and sustained regression across many cancer cell types, including lung cancer cells. In addition to its transport function, RLIP76 has many other cellular and physiological functions based on its domain structure, which includes a unique Ral-binding domain and a Rho GTPase activating protein (RhoGAP)-catalytic domain as well as docking sites for multiple signaling proteins. As a Ral effector, RhoGAP, and adapter protein, RLIP76 has been shown to play important roles in endocytosis, mitochondrial fission, cell spreading and migration, actin dynamics during gastrulation, and Ras-induced tumorigenesis. Additionally, RLIP76 is also important for stromal cell function in tumors, as it was recently shown to be required for efficient endothelial cell function and angiogenesis in solid tumors. However, RLIP76 knockout mice are viable, and blockade effects appear to be selective for implanted tumors in mice, suggesting the possibility that RLIP76-targeting drugs may be successful in clinical trials. In this review, we outline the many cellular and physiological functions of RLIP76 in normal and cancer cells, and discuss the potential for RLIP76-based therapeutics in lung cancer treatment.

Novel anti-cancer compounds for developing combinatorial therapies to target anoikis-resistant tumors

Anoikis, a cell death pathway induced by loss of normal cell-matrix attachment or upon adhesion to a non-native matrix, ensures the balance between proliferative potential of normal cells and maintenance of tissue integrity. Thereby, anoikis serves as a potential molecular barrier against oncogenic transformation of normal cells. Cancer cells acquire anoikis resistance for survival and distant metastatic progression. During the acquisition of anoikis resistance, tumors modulate multiple cell signaling parameters through changes in the expression of up-stream receptors and by dynamically calibrating the dependency on down-stream signaling cascades. Many compounds that target the tumor-acquired switches in integrins, tumor antigens, growth factors, metabolic pathways, oxidative and osmotic-stress signaling are in various phases of pre-clinical and clinical development. Combinatorial approaches maximize the therapeutic efficacy and minimize the activation of alternate signaling pathways, which will otherwise contribute to drug resistance. In this regard, an integrated analysis of the mechanisms of action of potential drugs and lead compounds that can target significant nodes of anoikis signaling networks will provide a rational frame-work for further development and clinical use of respective agents, by formulating more effective combinatorial therapies, in patients with distinct drug-sensitivity profiles.