Normal Cell Metabolism Research Articles

Oxidative stress and fish immune system: phagocytosis and leukocyte respiratory burst activity.

Molecular oxygen is a necessary compound for all aerobic organisms, although oxygen is a potent oxidant, which can cause oxidative stress (OS). OS occurs when there is an imbalance between the production of oxidant and antioxidants components, are result of normal cell metabolism, and many of these compounds play a fundamental role in several metabolic pathways. The organism produces several reactive oxygen species (ROS), but they are balanced by an antioxidant defense system that maintains the levels of these oxidizing compounds at an acceptable level. Many of these components are essential in the organism defense and their byproducts are considered potent bactericides that actively act in the destruction of invading pathogens. Fish immune system is composed of innate and acquired mechanisms of defense. Phagocytosis is an innate process of defense, which interconnects these two systems, since the pathogens processing by professional phagocytes is a fundamental stage for antibodies production. During phagocytosis there is production of ROS and consequent production of free radicals (FR), these compounds lead to the formation of potent bactericides to combat microorganisms. However, it is known that OS limits the immune response, with an impairment in defense compounds in an attempt to decrease the ROS production. Studies of fish FR production are preliminary and should be executed to evaluate the effects of ROS on fish, including their beneficial action against pathogens and its deleterious action on the oxidation of cellular components.

134 - Induction of metabolic oxidative stress and sensitization to radio-chemotherapies via targeting of NAMPT

Due to tumor heterogeneity related to the inherent metabolic plasticity of cancer cells, attempts to target lung cancer metabolism thus far have yielded limited success. One potential solution to this problem is targeting of specific metabolites that 1) are required by tumor cells of all metabolic phenotypes, 2) whose synthesis and/or breakdown are commonly dysregulated in tumor cells, and 3) whose levels are regulated by a limited number of targetable enzymes. One group of metabolites includes NAD+ as well as NADH, NADP+ and NADPH, all of which are generated from NAD+. Tumor cells preferentially rely on the salvage pathway of NAD+ synthesis driven by the rate-limiting enzyme nicotinamide phosphoribosyltransferase (NAMPT). We hypothesize that targeting of NAMPT will result in selective increases in markers of metabolic oxidative stress and sensitization of cancer cells to standard-of-care therapies and inhibitors of hydroperoxide metabolism. Physiologically relevant doses (10-50 nM) of NAMPT inhibitors (FK866, GMX-1778) are selectively toxic to lung cancer cells but not normal human fibroblasts. Toxicity is prevented by supplementation of nicotinamide mononucleotide, nicotinic acid, or nicotinamide riboside. NAMPT inhibition results in NAD(P)(H) and glutathione depletion as well as marked sensitization to ML-162 (Gpx4 inhibitor), Auranofin (TrxR inhibitor), cisplatin, ionizing radiation and pharmacological ascorbate (AscH-). These results suggest that NAMPT inhibitors may serve as promising adjuvants for cancer therapy based on their ability to selectively target fundamental differences in NAD(P)(H) metabolism in cancer versus normal cells. (Funded by T32CA78586 and R01CA182804).

Synthetic repetitive extragenic palindromic (REP) sequence as an efficient mRNA stabilizer for protein production and metabolic engineering in prokaryotic cells

In prokaryotic cells, 3'-5' exonucleases can attenuate messenger RNA (mRNA) directionally from the direction of the 3'-5' untranslated region (UTR), and thus improving the stability of mRNAs without influencing normal cell growth and metabolism is a key challenge for protein production and metabolic engineering. Herein, we significantly improved mRNA stability by using synthetic repetitive extragenic palindromic (REP) sequences as an effective mRNA stabilizer in two typical prokaryotic microbes, namely, Escherichia coli for the production of cyclodextrin glucosyltransferase (CGTase) and Corynebacterium glutamicum for the production of N-acetylglucosamine (GlcNAc). First, we performed a high-throughput screen to select 4 out of 380 REP sequences generated by randomizing 6 nonconservative bases in the REP sequence designed as the degenerate base "N." Secondly, the REP sequence was inserted at several different positions after the stop codon of the CGTase-encoding gene. We found that mRNA stability was improved only when the space between the REP sequence and stop codon was longer than 12 base pairs (bp). Then, by reconstructing the spacer sequence and secondary structure of the REP sequence, a REP sequence with 8 bp in a stem-loop was obtained, and the CGTase activity increased from 210.6 to 291.5 U/ml. Furthermore, when this REP sequence was added to the 3'-UTR of glucosamine-6-phosphate N-acetyltransferase 1 ( GNA1), which is a gene encoding a key enzyme GNA1 in the GlcNAc synthesis pathway, the GNA1 activity was increased from 524.8 to 890.7 U/mg, and the GlcNAc titer was increased from 4.1 to 6.0 g/L in C. glutamicum. These findings suggest that the REP sequence plays an important function as an mRNA stabilizer in prokaryotic cells to stabilize its 3'-terminus of the mRNA by blocking the processing action of the 3'-5' exonuclease. Overall, this study provides new insight for the high-efficiency overexpression of target genes and pathway fine-tuning in bacteria.

PO-266 The regulation mechanism of bcl-2 family on autophagy、apoptosis of motor skeletal muscle cells

Objective To summarize the localization and regulation mechanism of Bcl-2 family on autophagy and apoptosis of exercise skeletal muscle. In order to provide new Intervention idea for metabolic diseases, sports injuries and post-game recovery of sports skeletal muscle.
 Methods In the academic network of , CNKI, CQVIP, Wanfangshujuziyuanxitong-xueshuqikan, Elsevier Science Direct, and Journals@Ovid Full Text and other academic journals, search for Chinese and foreign literatures such as Bcl-2 protein, skeletal muscle, autophagy and apoptosis, and sort more than 170 articles, More than 50 articles are in line with the requirements, and the final reference is 49 articles.
 Results 1) The regulation of Bcl-2 family proteins on apoptosis of exercise skeletal muscle autophagy was divided into localization and streaming regulation; 2) Bcl-2 is located in the endoplasmic reticulum and binds beclin-1 to form a complex, Through stimulating ampk-ulki/akt-mtor pathway, FoxO, GAMKK underground, etc., the release signal of motor stress interferes with the decomposition of bcl-2-beclin-1 complex, releasing Beclin-1, activating autophagy; 3) The bcl-2 family protein is located in the mitochondrial membrane，exercise stress releases apoptotic signals→ BH3s activation or liberation of pro-apoptotic subfamily activity → recruitment of Bcl-2 family translocation to MOM → Bcl-2 family protein oligomerization → formation into MOMP→ finally promotion of cytochrome C Release→ activates apoptosis; 4) On the other hand, the Bc-2 family cooperates with intracellular Ca2+ signaling; the JNK phosphorylation pathway; the P53 gene and the ubiquitin protein Atg12 are streaming between autophagy and apoptosis.
 Conclusions Autophagy and apoptosis of skeletal muscle cells can eliminate ROS caused by oxidative stress, damaged organelles, misfolded proteins and severely damaged cell tissues, in order to maintain normal energy metabolism of muscle cells, control inflammatory damage, and improve Skeletal muscle cell movement adaptability. The Bcl-2 family is a major regulatory protein that controls apoptosis. It can also target and regulate autophagy in the endoplasmic reticulum. In addition, in coordination with multiple signaling factors, streaming between autophagy and apoptosis. It can be regarded as an important target protein for the intervention of skeletal muscle motor injury and improvement of skeletal muscle motor ability.

Selective human inhibitors of ATR and ATM render Leishmania major promastigotes sensitive to oxidative damage

All cellular processes, including those involved in normal cell metabolism to those responsible for cell proliferation or death, are finely controlled by cell signaling pathways, whose core proteins constitute the family of phosphatidylinositol 3-kinase-related kinases (PIKKs). Ataxia Telangiectasia Mutated (ATM) and Ataxia Telangiectasia and Rad3 related (ATR) are two important PIKK proteins that act in response to DNA damage, phosphorylating a large number of proteins to exert control over genomic integrity. The genus Leishmania belongs to a group of early divergent eukaryotes in evolution and has a highly plastic genome, probably owing to the existence of signaling pathways designed to maintain genomic integrity. The objective of this study was to evaluate the use of specific human inhibitors of ATR and ATM in Leishmania major. Bioinformatic analyses revealed the existence of the putative PIKK genes ATR and ATM, in addition to mTOR and DNA-PKcs in Leishmania spp. Moreover, it was possible to suggest that the inhibitors VE-821 and KU-55933 have binding affinity for the catalytic sites of putative L. major ATR and ATM, respectively. Promastigotes of L. major exposed to these inhibitors show slight growth impairment and minor changes in cell cycle and morphology. It is noteworthy that treatment of promastigotes with inhibitors VE-821 and KU-55933 enhanced the oxidative damage caused by hydrogen peroxide. These inhibitors could significantly reduce the number of surviving L. major cells following H2O2 exposure whilst also decreasing their evaluated IC50 to H2O2 to less than half of that observed for non-treated cells. These results suggest that the use of specific inhibitors of ATR and ATM in Leishmania interferes in the signaling pathways of this parasite, which can impair its tolerance to DNA damage and affect its genome integrity. ATR and ATM could constitute novel targets for drug development and/or repositioning for treatment of leishmaniases.

Effect of Dibutyltin Dilaurate on Triglyceride Metabolism through the Inhibition of the mTOR Pathway in Human HL7702 Liver Cells.

Dibutyltin dilaurate (DBTD) has multiple applications in daily life. However, DBTD is easily deposited in the liver and affects liver functions. This study was designed to explore the effects of DBTD on triglyceride metabolism in human normal hepatocyte HL7702 cells. Our results showed that the intracellular fat contents were dose-dependently decreased by DBTD. The expression of lipolysis genes and proteins were elevated while the lipogenesis genes and proteins were diminished by DBTD. The phosphorylation levels of ribosomal S6 kinase 1 were reduced by both rapamycin and DBTD, indicating that the mTOR pathway was suppressed possibly. The decreased sterol regulatory element-binding protein 1C (SREBP1C) transcription levels, as well as the increased peroxisome proliferator-activated receptor alpha (PPARα) transcription levels, caused by rapamycin and DBTD corresponded to the inactive mTOR pathway. In conclusion, it was possible that DBTD reduced the intracellular triglyceride through depressing the mTOR pathway and affecting its downstream transcription factors.

Abstract 5087: Human melanoma exosomes induce metabolic reprogramming in human adult dermal fibroblasts

Abstract The “seed and soil” hypothesis of cancer metastasis has led us to examine the role of tumor-derived exosomes on reprogramming stromal cells composing the tumor microenvironment. We used human adult dermal fibroblasts (HADF) in vitro as a model of the premetastatic niche. Specifically, we determined the role of human melanoma-derived exosomes (HMEX) on governing metabolic reprogramming of healthy HADF. HMEX from six melanoma cell lines (3 BRAF V600E mutant cell lines (526-mel, 888-mel and Hs 294T) and 3 BRAF wild-type cell lines (1300-mel, 2183-Her4 and HMCB)) were purified by size-exclusion chromatography. Using the fluorescent tag CellVue (Maroon) we demonstrated via ImageStream that HMEXs are rapidly taken up by HADF. Following 18 hours of exposure to HMEX, HADF increased aerobic glycolysis and reduced oxidative phosphorylation (OXPHOS) in vitro, as measured by Agilent Seahorse XFe96. We have also developed an immuno-biochip that captures exosomes via anti-CD63 antibodies and simultaneously detects exosomal microRNAs by cationic lipoplex nanoparticles (tCLN) containing molecular beacons. With this immuno-biochip, we demonstrated the presence of microRNAs miR-155 and miR-210 in HMEX, both of which work in concert to promote glycolysis and inhibit OXPHOS. The result has been consistent across all HMEXs from the six different melanoma cell lines. Our findings reveal a correlation between metabolic function and the presence of metabolically active microRNAs in HMEX that control aerobic glycolysis and OXPHOS of normal fibroblasts. Melanoma exosomes are potentially key players in promoting tumor progression by modulating normal stromal cell metabolism and creating an environment that is conducive to metastasis. Oxygen Consumption Rate (OCR) pmol/minHADF onlyHADF + HMEX 17.5 μgHADF + HMEX 25 μgHADF + HMEX 50μgHADF + HMEX100μgBasal OCR52.6753.5850.9638.2031.56 Citation Format: Shin La Shu, Cheryl L. Allen, Yunchen Yang, Orla Maguire, Hans Minderman, Arindam Sen, Michael J. Ciesielski, Katherine A. Collins, Peter J. Bush, Martin Morgan, Yun Wu, Richard B. Bankert, Marc S. Ernstoff. Human melanoma exosomes induce metabolic reprogramming in human adult dermal fibroblasts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5087.

Bioenergetic and proteomic profiling to screen small molecule inhibitors that target cancer metabolisms

Cancer cells can reprogram their metabolic machinery to survive. This altered metabolism, which is distinct from the metabolism of normal cells, is thought to be a possible target for the development of new cancer therapies. In this study, we constructed a screening system that focuses on bioenergetic profiles (specifically oxygen consumption rate and extracellular acidification rate) and characteristic proteomic changes. Thus, small molecules that target cancer-specific metabolism were investigated. We screened the chemical library of RIKEN Natural Products Depository (NPDepo) and found that unantimycin A, which was recently isolated from the fraction library of microbial metabolites, and NPL40330, which is derived from a chemical library, inhibit mitochondrial respiration. Furthermore, we developed an in vitro reconstitution assay method for mitochondrial electron transport chain using semi-intact cells with specific substrates for each complex of the mitochondrial electron transport chain. Our findings revealed that NPL40330 and unantimycin A target mitochondrial complexes I and III, respectively.

Mitochondrial Delivery of Phenol Substructure Triggers Mitochondrial Depolarization and Apoptosis of Cancer Cells.

Antitumor chemotherapy remains one of the most important challenge of the medicinal chemistry. Emerging research in chemotherapy is focused on exploiting the biochemical differences between cancer cell and normal cell metabolism in order to reduce the side effects and increase antitumor therapy efficacy. The higher mitochondrial transmembrane potential of cancer cells compared to not-transformed cells favors the intra-mitochondrial accumulation of cationic drugs in the former. This feature could be exploited to allow selective delivery of antineoplastic drugs to the cancer cells. In this work we designed and synthetized phenol derivatives joined to the triphenylphosphonium (TPP) cation, a well-known vector for mitochondrial targeting. Two designed phenol TPP-derivatives 1 and 2 show remarkable cytotoxic activity against different cancer cell lines, but were less toxic against normal cells. The differential cytotoxicity relied on the higher mitochondrial biogenesis and oxidative-phosphorylation metabolism of the former. By reducing mitochondrial mass and energetic metabolism, and increasing at the same time the levels of intra-mitochondrial reactive oxygen species, phenol TPP-derivatives 1 and 2 induced mitochondria depolarization and triggered a caspase 9/3-mediated apoptosis, limited to cancer cells. This work provides the rationale to further develop phenol TPP-derivatives targeting mitochondria as new and selective anticancer tools.

Endosomal-Lysosomal Cholesterol Sequestration by U18666A Differentially Regulates Amyloid Precursor Protein (APP) Metabolism in Normal and APP-Overexpressing Cells.

Amyloid β (Aβ) peptide, derived from amyloid precursor protein (APP), plays a critical role in the development of Alzheimer's disease. Current evidence indicates that altered levels or subcellular distribution of cholesterol can regulate Aβ production and clearance, but it remains unclear how cholesterol sequestration within the endosomal-lysosomal (EL) system can influence APP metabolism. Thus, we evaluated the effects of U18666A, which triggers cholesterol redistribution within the EL system, on mouse N2a cells expressing different levels of APP in the presence or absence of extracellular cholesterol and lipids provided by fetal bovine serum (FBS). Our results reveal that U18666A and FBS differentially increase the levels of APP and its cleaved products, the α-, β-, and η-C-terminal fragments, in N2a cells expressing normal levels of mouse APP (N2awt), higher levels of human wild-type APP (APPwt), or "Swedish" mutant APP (APPsw). The cellular levels of Aβ1-40/Aβ1-42 were markedly increased in U18666A-treated APPwt and APPsw cells. Our studies further demonstrate that APP and its cleaved products are partly accumulated in the lysosomes, possibly due to decreased clearance. Finally, we show that autophagy inhibition plays a role in mediating U18666A effects. Collectively, these results suggest that altered levels and distribution of cholesterol and lipids can differentially regulate APP metabolism depending on the nature of APP expression.

The Role for Myc in Coordinating Glycolysis, Oxidative Phosphorylation, Glutaminolysis, and Fatty Acid Metabolism in Normal and Neoplastic Tissues.

That cancer cells show patterns of metabolism different from normal cells has been known for over 50 years. Yet, it is only in the past decade or so that an appreciation of the benefits of these changes has begun to emerge. Altered cancer cell metabolism was initially attributed to defective mitochondria. However, we now realize that most cancers do not have mitochondrial mutations and that normal cells can transiently adopt cancer-like metabolism during periods of rapid proliferation. Indeed, an encompassing, albeit somewhat simplified, conceptual framework to explain both normal and cancer cell metabolism rests on several simple premises. First, the metabolic pathways used by cancer cells and their normal counterparts are the same. Second, normal quiescent cells use their metabolic pathways and the energy they generate largely to maintain cellular health and organelle turnover and, in some cases, to provide secreted products necessary for the survival of the intact organism. By contrast, undifferentiated cancer cells minimize the latter functions and devote their energy to producing the anabolic substrates necessary to maintain high rates of unremitting cellular proliferation. Third, as a result of the uncontrolled proliferation of cancer cells, a larger fraction of the metabolic intermediates normally used by quiescent cells purely as a source of energy are instead channeled into competing proliferation-focused and energy-consuming anabolic pathways. Fourth, cancer cell clones with the most plastic and rapidly adaptable metabolism will eventually outcompete their less well-adapted brethren during tumor progression and evolution. This attribute becomes increasingly important as tumors grow and as their individual cells compete in a constantly changing and inimical environment marked by nutrient, oxygen, and growth factor deficits. Here, we review some of the metabolic pathways whose importance has gained center stage for tumor growth, particularly those under the control of the c-Myc (Myc) oncoprotein. We discuss how these pathways differ functionally between quiescent and proliferating normal cells, how they are kidnapped and corrupted during the course of transformation, and consider potential therapeutic strategies that take advantage of common features of neoplastic and metabolic disorders.

A Novel Dual-cre Motif Enables Two-Way Autoregulation of CcpA in Clostridium acetobutylicum.

The master regulator CcpA (catabolite control protein A) manages a large and complex regulatory network that is essential for cellular physiology and metabolism in Gram-positive bacteria. Although CcpA can affect the expression of target genes by binding to a cis-acting catabolite-responsive element (cre), whether and how the expression of CcpA is regulated remain poorly explored. Here, we report a novel dual-cre motif that is employed by the CcpA in Clostridium acetobutylicum, a typical solventogenic Clostridium species, for autoregulation. Two cre sites are involved in CcpA autoregulation, and they reside in the promoter and coding regions of CcpA. In this dual-cre motif, creP, in the promoter region, positively regulates ccpA transcription, whereas creORF, in the coding region, negatively regulates this transcription, thus enabling two-way autoregulation of CcpA. Although CcpA bound creP more strongly than creORFin vitro, the in vivo assay showed that creORF-based repression dominates CcpA autoregulation during the entire fermentation. Finally, a synonymous mutation of creORF was made within the coding region, achieving an increased intracellular CcpA expression and improved cellular performance. This study provides new insights into the regulatory role of CcpA in C. acetobutylicum and, moreover, contributes a new engineering strategy for this industrial strain.IMPORTANCE CcpA is known to be a key transcription factor in Gram-positive bacteria. However, it is still unclear whether and how the intracellular CcpA level is regulated, which may be essential for maintaining normal cell physiology and metabolism. We discovered here that CcpA employs a dual-cre motif to autoregulate, enabling dynamic control of its own expression level during the entire fermentation process. This finding answers the questions above and fills a void in our understanding of the regulatory network of CcpA. Interference in CcpA autoregulation leads to improved cellular performance, providing a new useful strategy in genetic engineering of C. acetobutylicum Since CcpA is widespread in Gram-positive bacteria, including pathogens, this dual-cre-based CcpA autoregulation would be valuable for increasing our understanding of CcpA-based global regulation in bacteria.

Endoplasmic Reticulum Stress Facilitates the Survival and Proliferation of Nucleus Pulposus Cells in TNF-α Stimulus by Activating Unfolded Protein Response.

Intervertebral disc (IVD) degeneration is closely related to inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α). The endoplasmic reticulum (ER) serves several important cell functions, which are essential for normal cell metabolism and survival. This study aims to clarify the role of ER stress and unfolded protein response (UPR) in TNF-α-induced biological changes in rat nucleus pulposus cells (NPCs) and IVD degeneration. In our research, rat NPCs were cultured with different concentrations of TNF-α in the presence or absence of ER stress inhibitors. Related genes and proteins were measured by immunofluorescence staining, quantitative real-time PCR, and Western blot analyses to monitor ER stress. Cell proliferation was evaluated by CCK-8 assay and cyclin D1 expression. Apoptosis was detected by flow cytometry and Western blot analyses. Our results showed that TNF-α induced the apoptosis of some NPCs in the early stage and then accelerated the proliferation of surviving cells. In addition, TNF-α stimulus upregulated ER stress markers and initiated UPR. However, these effects could be reversed by inhibitors, thereby reducing cell proliferation and enhancing apoptosis. In conclusion, ER stress reinforces the survival and proliferation of NPCs in TNF-α stimulus by activating UPR signaling, which could be an important therapeutic target in the future.

Metabolic Alterations in Cancer Cells and the Emerging Role of Oncometabolites as Drivers of Neoplastic Change.

The mitochondrion is an important organelle and provides energy for a plethora of intracellular reactions. Metabolic dysregulation has dire consequences for the cell, and alteration in metabolism has been identified in multiple disease states—cancer being one. Otto Warburg demonstrated that cancer cells, in the presence of oxygen, undergo glycolysis by reprogramming their metabolism—termed “aerobic glycolysis”. Alterations in metabolism enable cancer cells to gain a growth advantage by obtaining precursors for macromolecule biosynthesis, such as nucleic acids and lipids. To date, several molecules, termed “oncometabolites”, have been identified to be elevated in cancer cells and arise from mutations in nuclear encoded mitochondrial enzymes. Furthermore, there is evidence that oncometabolites can affect mitochondrial dynamics. It is believed that oncometabolites can assist in reprogramming enzymatic pathways and providing cancer cells with selective advantages. In this review, we will touch upon the effects of normal and aberrant mitochondrial metabolism in normal and cancer cells, the advantages of metabolic reprogramming, effects of oncometabolites on metabolism and mitochondrial dynamics and therapies aimed at targeting oncometabolites and metabolic aberrations.

128 - Effects Beyond Mitochondria in Triple Negative Breast Cancer of Mitochondria-targeted SG1 Nitroxide

Triple negative breast cancer (TNBC) is a harsh form of breast cancer that does not express estrogen (ER), progesterone (PR), and human epidermal growth factor (HER2) receptors. Currently, there is no effective therapy for TNBC. However, TNBC is characterized by mitochondrial dysfunction, elevated glycolysis, and increased generation of reactive oxygen species (ROS) as compared with receptor positive breast cancer cells. Then, targeting the biochemical differences between cancer and normal cell metabolism and mitochondrial bioenergetics with mitochondria-targeted nitroxides (MTNs) is a viable strategy. MTNs have been shown to exert selective cytotoxic effects in breast cancer but not in normal cells. Here, we tested the antitumor effects of Mito-SG1 [(N-tert-butyl- N-[1-diethylphosphono-(2,2-dimethylpropyl)] nitroxide conjugated to an alkyl triphenylphosphonium cation, in TNBC and normal breast epithelial cells. Mito-SG1 selectively induced a dose-dependent inhibition of cell viability and growth in TNBC and non-TNBC cells but not in normal MCF-10A cells. Treatment with Mito-SG1 also induced a concentration-dependent change in mitochondrial membrane potential and an increase in ROS production. We also established that Mito-SG1 targets mitochondria inducing a decrease in oxygen consumption rate (OCR), maximal respiration and spare respiratory capacity in TNBC and non-TNBC cells. Treatment with Mito-SG1 prompted a switch in both TNBC baseline and stressed metabolic phenotypes, suggesting that it impaired the cells' ability to meet their energetic and metabolic demands for survival by targeting mitochondria. Interestingly, we also found that Mito-SG1 effects extend beyond targeting mitochondria. Treatment of TNBC cells demonstrated that Mito-SG1 also impacts the Ras-MEK-ERK pathway, preventing downstream phosphorylation of kinases. Together, our results demonstrate that Mito-SG1 could be used as a novel alternative for the treatment of TNBC and that its effects outspread beyond targeting mitochondria.

Relations Between Oxidized Low-density Lipoproteins and Fat-soluble Vitamin Concentrations in Obese Children – Preliminary Study

IntroductionAlthough lipid peroxidation products are formed during normal cell metabolism, they appear mostly in pathological conditions via producing an excess of free radicals that can react with unsaturated fatty acids, in particular low-density lipoprotein (LDL).The aim of this study was to investigate the relations between oxidized LDL (oxLDL), the fat-soluble vitamin status and the anthropometric parameters in prepubertal obese children.Material and methodsThirty-two obese (SDS-BMI >2) and 25 non-obese children (SDS-BMI <-1+1>) were included in the study. The concentration of oxLDL was determined in the serum by the ELISA assay. Vitamin A and E were measured by the high-pressure liquid chromatography method. Total cholesterol, LDL- and HDL-cholesterol, and triglyceride levels were determined by enzymatic methods.ResultsThe concentrations of oxLDL and vitamin A were higher in obese children than in normal-weight controls by about 50% (p=0.01) and 40% (p=0.001), respectively. In obese children the significant positive correlation was found between oxLDL and vitamin A concentrations (p<0.05). In addition, oxLDL correlated positively with BMI values (p<0.05) and the amount of fat mass (kg) (p<0.02) in these patients. Concentrations of vitamins A and E correlated with the level of total cholesterol (p<0.05; p<0.01, respectively). Moreover, a positive correlation between vitamin E and LDL-cholesterol was observed (p<0.05).ConclusionsOur preliminary study shows that oxLDL starts early during the prepubertal period and may precede atherosclerotic lesions. We suggest there is an occurrence of relationships between vitamin A and oxidized LDL in prepubertal obese children. Vitamin A and E concentrations are also associated with dyslipidemia in these patients.

Oxidative damage of 18S and 5S ribosomal RNA in digestive gland of mussels exposed to trace metals

Numerous studies have shown the ability of trace metals to accumulate in marine organisms and cause oxidative stress that leads to perturbations in many important intracellular processes, including protein synthesis. This study is mainly focused on the exploration of structural changes, like base modifications, scissions, and conformational changes, caused in 18S and 5S ribosomal RNA (rRNA) isolated from the mussel Mytilus galloprovincialis exposed to 40μg/L Cu, 30μg/L Hg, or 100μg/L Cd, for 5 or 15days. 18S rRNA and 5S rRNA are components of the small and large ribosomal subunit, respectively, found in complex with ribosomal proteins, translation factors and other auxiliary components (metal ions, toxins etc). 18S rRNA plays crucial roles in all stages of protein synthesis, while 5S rRNA serves as a master signal transducer between several functional regions of 28S rRNA. Therefore, structural changes in these ribosomal constituents could affect the basic functions of ribosomes and hence the normal metabolism of cells. Especially, 18S rRNA along with ribosomal proteins forms the decoding centre that ensures the correct codon-anticodon pairing. As exemplified by ELISA, primer extension analysis and DMS footprinting analysis, each metal caused oxidative damage to rRNA, depending on the nature of metal ion and the duration of exposure. Interestingly, exposure of mussels to Cu or Hg caused structural alterations in 5S rRNA, localized in paired regions and within loops A, B, C, and E, leading to a continuous progressive loss of the 5S RNA structural integrity. In contrast, structural impairments of 5S rRNA in mussels exposed to Cd were accumulating for the initial 5days, and then progressively decreased to almost the normal level by day 15, probably due to the parallel elevation of metallothionein content that depletes the pools of free Cd. Regions of interest in 18S rRNA, such as the decoding centre, sites implicated in the binding of tRNAs (A- and P-sites) or translation factors, and areas related to translation fidelity, were found to undergo significant metal-induced conformational alterations, leading either to loosening of their structure or to more compact folding. These modifications were associated with parallel alterations in the translation process at multiple levels, a fact suggesting that structural perturbations in ribosomes, caused by metals, pose significant hurdles in translational efficiency and fidelity.

Pharmacological Inhibitors of NAD Biosynthesis as Potential An ticancer Agents.

Alteration of cellular metabolism is a hallmark of cancer, which underlies exciting opportunities to develop effective, anti-cancer therapeutics through inhibition of cancer metabolism. Nicotinamide Adenine Dinucleotide (NAD+), an essential coenzyme of energy metabolism and a signaling molecule linking cellular energy status to a spectrum of molecular regulation, has been shown to be in high demand in a variety of cancer cells. Depletion of NAD+ by inhibition of its key biosynthetic enzymes has become an attractive strategy to target cancer. The main objective of this article is to review the recent patents which develop and implicate the chemical inhibitors of the key NAD+ biosynthetic enzymes for cancer treatment. We first discuss the biological principles of NAD+ metabolism in normal and malignant cells, with a focus on the feasibility of selectively targeting cancer cells by pharmacological inhibition of nicotinamide phosphoribosyltransferase (NAMPT) and indoleamine/tryptophan 2,3-dioxygenases (IDO/TDO), the rate-limiting salvage and de novo NAD+ biosynthetic enzymes, respectively. We then analyze a series of recent patents on development and optimization of chemical scaffolds for inhibiting NAMPT or IDO/TDO enzymes as potential anticancer drugs. Conclusion and Results: We have reviewed 16 relevant patents published since 2015, and summarized the chemical properties, mechanisms of action and proposed applications of the patented compounds. Without a better understanding of the properties of these compounds, their utility for further optimization and clinical use is unknown. For the compounds that have been tested using cell and mouse models of cancer, results look promising and clinical trials are currently ongoing to see if these results translate to improved cancer treatments.

Different molecular organization of two carotenoids, lutein and zeaxanthin, in human colon epithelial cells and colon adenocarcinoma cells

Two cell lines, human normal colon epithelial cells (CCD 841 CoTr) and human colon adenocarcinoma cells (HT-29) were cultured in the presence of exogenous carotenoids, either zeaxanthin or lutein. Both carotenoids demonstrated cytotoxicity with respect to cancer cells but not to normal cells. Cells from both the cell lines were analyzed with application of fluorescence lifetime imaging microscopy and Raman scattering microscopy. Both imaging techniques show effective incorporation of carotenoid molecules into growing cells. Comparison of the Raman scattering and fluorescence lifetime characteristics reveals different molecular organization of carotenoids in the carcinoma and normal cells. The main difference consists in a carotenoid aggregation level which is substantially lower in the carcinoma cells as compared to the normal cells. Different molecular organization of carotenoids was interpreted in terms of a different metabolism of normal and carcinoma cells and has been concluded to provide a possibility of cancer diagnosis based on spectroscopic analyses.

A Cisplatin Derivative Tetra-Pt(bpy) as an Oncotherapeutic Agent for Targeting ALT Cancer.

In approximately 15% of human cancers, telomere length is maintained independently of telomerase by the homologous recombination (HR)-mediated alternative lengthening of telomeres (ALT) pathway. Whether the ALT pathway can be exploited for therapeutic treatment remains unknown. The purpose of this study is to develop oncotherapeutic agent to target ALT cancers. Surface plasmon resonance assay, antibody to G-quadruplex, and fluorescence in situ hybridization (FISH) were used to discover Tetra-Pt(bpy), a cisplatin derivative that specifically targets telomeric G-quadruplex. We used immunofluorescence, FISH, C-circle assay, and chromosome orientation FISH to evaluate the inhibitory effect of Tetra-Pt(bpy) on ALT activity in human ALT cancers. The shortening of telomere length induced by Tetra-Pt(bpy) was determined by telomere restriction fragment or Q-FISH. Cell destination after Tetra-Pt(bpy) treatment was determined by β-gal staining or apoptosis assay. Nude mice (n = 4 per group) were injected with U2OS cells to evaluate the effects of Tetra-Pt(bpy) on tumor growth. All statistical tests were two-sided. Tetra-Pt(bpy) inhibits the strand invasion/annealing step of telomeric homologous recombination by selectively converting telomeric ssDNA to a G-quadruplex. ALT-cells treated with Tetra-Pt(bpy) show fewer ALT-associated promyelocytic leukemia bodies (untreated: mean±SD = 5.9±0.2 vs treated: mean±SD = 3.1±0.1, P < .001), fewer extrachromosomal C-circles (untreated: mean±SD = 100.5±1.6 vs treated: mean±SD = 18.0±1.7, P < .001), and reduced telomere sister chromatin exchanges (untreated: mean±SD = 25.2%±1.5% vs treated: mean±SD = 13.1%±1.9%, P < .001). Consequently, critically short telomeres accumulate after multiple population doublings (untreated: mean±SD = 18.9%±1.7% vs treated: mean±SD = 57.4%±2.2%, P < .001), resulting in cell death by apoptosis or senescence. In vivo, Tetra-Pt(bpy) severely inhibits the growth of ALT-cell xenograft tumors in mice (untreated: mean±SD = 57.1±3.7 mm 3 vs treated: mean±SD = 19.0±3.2 mm 3 , P < .001). Importantly, Tetra-Pt(bpy) exhibits no adverse effects on proliferation, gene expression, or telomere metabolism in normal cells. These results reveal the potential of Tetra-Pt(bpy) as a novel oncotherapeutic agent for targeting ALT cancer cells.