Contribution of HSP90 Cleavage to the Cytotoxic Effect of Suberoylanilide Hydroxamic Acid In Vivo and the Involvement of TXNIP in HSP90 Cleavage.

Heat shock protein (HSP) 90 is expressed in most living organisms, and several client proteins of HSP90 are necessary for cancer cell survival and growth. Previously, we found that HSP90 was cleaved by histone deacetylase (HDAC) inhibitors and proteasome inhibitors, and the cleavage of HSP90 contributes to their cytotoxicity in K562 leukemia cells. In this study, we first established mouse xenograft models with K562 cells expressing the wild-type or cleavage-resistant mutant HSP90ß and found that the suppression of tumor growth by the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) was interrupted by the mutation inhibiting the HSP90 cleavage in vivo. Next, we investigated the possible function of thioredoxin interacting protein (TXNIP) in the HSP90 cleavage induced by SAHA. TXNIP is a negative regulator for thioredoxin, an antioxidant protein. SAHA transcriptionally induced the expression of TXNIP in K562 cells. HSP90 cleavage was induced by SAHA also in the thymocytes of normal mice and suppressed by an anti-oxidant and pan-caspase inhibitor. When the thymocytes from the TXNIP knockout mice and their wild-type littermate control mice were treated with SAHA, the HSP90 cleavage was detected in the thymocytes of the littermate controls but suppressed in those of the TXNIP knockout mice suggesting the requirement of TXNIP for HSP90 cleavage. We additionally found that HSP90 cleavage was induced by actinomycin D, ß-mercaptoethanol, and p38 MAPK inhibitor PD169316 suggesting its prevalence. Taken together, we suggest that HSP90 cleavage occurs also in vivo and contributes to the anti-cancer activity of various drugs in a TXNIP-dependent manner.

Antimicrobial and anti-inflammatory activity of Cystatin C on human gingival fibroblast incubated with Porphyromonas gingivalis.

Background: Periodontal disease is considered one of the most prevalent chronic infectious diseases, often leading to the disruption of tooth-supporting tissues, including alveolar bone, causing tooth mobility and loss. Porphyromonas gingivalis is considered the major etiological agent of this disease, having a plethora of virulence factors, including, lipopolysaccharides (LPS), hemolysins, and proteinases. Antimicrobial peptides are one of the main components of the innate immune response that inhibit the growth of P. gingivalis. The aim of this study was to analyze the antimicrobial activity of cystatin C and to assess the effect on the inflammatory and anti-inflammatory cytokines, the production of reactive oxygen species, and in the release of nitric oxide by human gingival fibroblasts incubated with P. gingivalis in the presence and absence of cystatin C. Methods: P. gingivalis ATCC 33277 was exposed to cystatin C for 24h and co-cultured with human gingival fibroblasts (HGFs) ATCC CRL-2014. The effect of cystatin on growth of P. gingivalis and HGFs was evaluated. Pro-inflammatory (TNFα, IL-1ß) and anti-inflammatory (IL-10) cytokines were determined by ELISA in the supernatants of HGFs incubated with P. gingivalis exposed to cystatin C. Additionally, nitrites and reactive oxygen species (ROS) production were evaluated. Results: Cystatin Cinhibited the growth of P. gingivalis without affecting HGFs. Incubation of HGFs with P. gingivalis led to a significant increase of TNF-α and IL-1ß. In contrast, HGFs incubated with P. gingivalis exposed to cystatin C showed a decreased production of both cytokines, whereas IL-10 was enhanced. Incubation of HGFs with P. gingivalis led to an increase of nitric oxide (NO) and ROS production, which was reduced in the presence of the peptide. Conclusions: Cystatin C inhibits the growth of P. gingivalis and decreases the inflammatory cytokines, ROS, and NO production during infection of HGFs with P. gingivalis. Knowledge on the antimicrobial and immunomodulatory properties of cystatin C could aid in the design of new therapeutic approaches to facilitate the elimination of this bacterium to improve the treatment of periodontal disease.

Impact of ETNK1 somatic mutations on phosphoethanolamine synthesis, ROS production and DNA damage.

Recently we showed that Ethanolamine Kinase 1 (ETNK1) mutations cause a decreased synthesis of phosphoethanolamine, and that phosphoethanolamine is able to modulate mitochondrial activity through competition with succinate for complex II. The decreased phosphoethanolamine concentration leads to increased mitochondria activity and reactive oxygen species production, which causes the accumulation of new mutations.

Reactive Oxygen Species and Oxidative Stress in the Pathogenesis and Progression of Genetic Diseases of the Connective Tissue.

Connective tissue is known to provide structural and functional "glue" properties to other tissues. It contains cellular and molecular components that are arranged in several dynamic organizations. Connective tissue is the focus of numerous genetic and nongenetic diseases. Genetic diseases of the connective tissue are minority or rare, but no less important than the nongenetic diseases. Here we review the impact of reactive oxygen species (ROS) and oxidative stress on the onset and/or progression of diseases that directly affect connective tissue and have a genetic origin. It is important to consider that ROS and oxidative stress are not synonymous, although they are often closely linked. In a normal range, ROS have a relevant physiological role, whose levels result from a fine balance between ROS producers and ROS scavenge enzymatic systems. However, pathology arises or worsens when such balance is lost, like when ROS production is abnormally and constantly high and/or when ROS scavenge (enzymatic) systems are impaired. These concepts apply to numerous diseases, and connective tissue is no exception. We have organized this review around the two basic structural molecular components of connective tissue: The ground substance and fibers (collagen and elastic fibers).

Interplay between inflammation and cancer.

Tumor-promoting inflammation is one of the hallmarks of cancer. It has been shown that cancer development is strongly influenced by both chronic and acute inflammation process. Progress in research on inflammation revealed a connection between inflammatory processes and neoplastic transformation, the progression of tumour, and the development of metastases and recurrences. Moreover, the tumour invasive procedures (both surgery and biopsy) affect the remaining tumour cells by increasing their survival, proliferation and migration. One of the concepts explaining this phenomena is an induction of a wound healing response. While in normal tissue it is necessary for tissue repair, in tumour tissue, induction of adaptive and innate immune response related to wound healing, stimulates tumour cell survival, angiogenesis and extravasation of circulating tumour cells. It has become evident that certain types of immune response and immune cells can promote tumour progression more than others. In this review, we focus on current knowledge on carcinogenesis and promotion of cancer growth induced by inflammatory processes.

Ramalin, an antioxidant compound derived from Antarctic lichen, prevents progression of liver fibrosis induced by dimethylnitrosamine (DNM) in rats.

Hepatic fibrosis is characterized by the excessive accumulation of extracellular matrix (ECM), primarily collagen, within the liver. Because reactive oxygen species (ROS) has been implicated in its pathogenesis, the use of antioxidants as a potential treatment has been broadly explored. Here, we investigated the hepatoprotective properties of ramalin (RM), a compound extracted from the Antarctic lichen Ramalina terebrata, against hepatic fibrosis in vitro and in vivo. RM suppressed hepatic stellate cell (HSC) activation in vitro without any significant signs of adverse effects on the cells tested, and the accumulation of ECM was dramatically reduced in the liver tissue. Oral administration of RM in rats noticeably improved the gross appearance of the liver with increased body and liver weight relative to the DMN injected rats, and all of the serum biochemical markers returned to the normal range. RM treatment have ameliorated hepatic fibrosis in rats induced by DMN by repressing α-smooth muscle actin (α-SMA) and upregulating heme oxygenase-1 (HO-1). In addition, RM significantly reduced collagen accumulation, and levels of malondialdehyde (MDA) and hydroxyproline (HP) in the liver tissue of DMN injected rats. The efficacy exerted by RM was through erythroid 2-related factor 2 (Nrf2) mediated antioxidant response proteins such as HO-1 and NAD(P)H quinone dehydrogenase 1 (NQO-1). Our results show the beneficial effect of RM against the progression of hepatic fibrosis.

Effects of δ-tocotrienol on ochratoxin A-induced nephrotoxicity in rats.

Ochratoxin A (OTA), is a natural contaminant of the food chain worldwide involved in the development of different type of cancers in animals and humans. Several studies suggested that oxidative damage might contribute to increase the cytotoxicity and carcinogenicity capabilities of OTA. The aim of this study was to evaluate the possible protective effect of δ-tocotrienol (Delta), a natural form of vitamin E, against OTA-induced nephrotoxicity. Male Sprague-Dawley rats were treated with OTA and/or Delta by gavage for 14 days. Our results shown that OTA treatment induced the increase of reactive oxigen species production correlated to a strong reduction of Glomerular Filtration Rate (GFR) and absoluted fluid reabsorption (Jv) with conseguent significant increase in blood pressure. Consistent, we noted in the kidney of rats treated with OTA, an increase in malondialdheyde and dihydroethidium production and a reduction of the activity of the catalase, superoxide dismutase, and glutathione peroxidase. Conversly, in the rat group subjected to the concomitant treatment OTA plus Delta, we observed the restored effect, compared the OTA treatment group, on blood pressure, GFR, Jv, and all activities of renal antioxidant enzymes. Finally, as far as concern the tissue damage induced by OTA and measured evaluating fibronectin protein levels, we observed that in OTA plus Delta group this effect is not restored. Our findings releval that a mechanism underlying the renal toxicity induced by OTA is the oxidative stress and provide a new rationale to use a Delta in order to protect, at least in part, against OTA-induced nephrotoxicity.

Alkynyl gold(I) complex triggers necroptosis via ROS generation in colorectal carcinoma cells.

Given the rise of apoptosis-resistant tumors, there exist a growing interest in developing new drugs capable of inducing different types of cell death to reduce colorectal cancer-related death rates. As apoptosis and necroptosis do not share cellular machinery, necroptosis induction may have a great therapeutic potential on those apoptosis-resistant cancers, despite the inflammatory effects associated with it. We have synthesized an alkynyl gold(I) complex [Au(CC-2-NC5H4)(PTA)] whose anticancer effect was tested on the colorectal adenocarcinoma Caco-2 cell line. With regard to its mechanism of action, this gold complex enters the mitochondria and disrupts its normal function, leading to an increase in ROS production, which triggers necroptosis. Necroptosis induction has been found dependent of TNF-α (Tumor necrosisfactor α) and TNFR1(Tumor necrosisfactor receptor 1) binding, RIP1(Receptor-Interacting Protein 1) activation and NF-κB (Nuclear Factor Kappa-Light-Chain-Enhancer of Activated B Cells) signaling. Moreover, the antitumor potential of [Au(CC-2-NC5H4)(PTA)] has also been confirmed on the 3D cancer model spheroid. Overall, the obtained data show firstly that gold complexes might have the ability of inducing necroptosis, and secondarily that our compound [Au(CC-2-NC5H4)(PTA)] is an interesting alternative to current chemotherapy drugs in cases of apoptosis resistance.

Oxidative stress, microRNAs and cytosolic calcium homeostasis.

Reactive oxygen species increase cytosolic [Ca(2+)], (Cai), and also modulate the expression of some microRNAs (miRNAs), however the link among oxidative stress, miRNAs and Cai is poorly characterized. In this review we have focused on three groups of miRNAs: (a) miRNAs that are modulated both by ROS and Cai: miR-181a and miR-205; (b) miRNAs that are modulated by ROS and have an effect on Cai: miR-1, miR-21, miR-24, miR-25, miR-185 and miR-214; (c) miRNAs that modulate both ROS and Cai: miR-133; miR-145, miR-495, and we have analyzed their effects on cell signaling and cell function. Finally, in the last section we have examined the role of these miRNAs in the skin, under conditions associated with enhanced oxidative stress, i.e. skin aging, the response to ultraviolet light and two important skin diseases, psoriasis and atopic dermatitis. It is apparent that although some experimental evidence is already available on (a) the role of Cai in miRNAs expression and (b) on the ability of some miRNAs to modulate Cai-dependent intracellular signaling, these research lines are still largely unexplored and represent important areas of future studies.

AMPKα1 controls hepatocyte proliferation independently of energy balance by regulating Cyclin A2 expression.

BACKGROUND: AMP-activated protein kinase (AMPK) is an evolutionarily conserved sensor of cellular energy status that contributes to restoration of energy homeostasis by slowing down ATP-consuming pathways and activating ATP-producing pathways. Unexpectedly, in different systems, AMPK is also required for proper cell division. In the current study, we evaluated the potential effect of the AMPK catalytic subunit, AMPKα1, on hepatocyte proliferation. METHODS: Hepatocyte proliferation was determined in AMPKα1 knockout and wild-type mice in vivo after two thirds partial hepatectomy, and in vitro in primary hepatocyte cultures. The activities of metabolic and cell cycle-related signaling pathways were measured. RESULTS: After partial hepatectomy, hepatocytes proliferated rapidly, correlating with increased AMPK phosphorylation. Deletion of AMPKα1 delayed liver regeneration by impacting on G1/S transition phase. The proliferative defect of AMPKα1-deficient hepatocytes was cell autonomous, and independent of energy balance. The priming phase, lipid droplet accumulation, protein anabolic responses and growth factor activation after partial hepatectomy occurred normally in the absence of AMPKα1 activity. By contrast, mRNA and protein expression of cyclin A2, a key driver of S phase progression, were compromised in the absence of AMPK activity. Importantly, AMPKα1 controlled cyclin A2 transcription mainly through the ATF/CREB element. CONCLUSIONS: Our study highlights a novel role for AMPKα1 as a positive regulator of hepatocyte division occurring independently of energy balance.

Modulation of the antioxidant/pro-oxidant balance, cytotoxicity and antiviral actions of grape seed extracts.

Grape seed extracts (GSEs) were investigated in yeast cells harbouring defects in their antioxidant system (regarding the cellular growth and growth recovery from H2O2 insult). GSEs antioxidant activity was detected in wild-type and mutant strains Δcta1, Δgsh1 and Δoye2glr1, while pro-oxidant activity in Δsod1 cells was seen. Assessment of proliferation of prostate cancer PC3 and HBV-replicating HepG2 2.2.15 cells treated with GSEs has shown higher cytotoxicity of red grape seed extract (RW) than white grape seed extract (WW) subjective to dose and period of administration. No antiviral effect was detected by measuring the secreted virion particles in HepG2 2.2.15 cells treated with GSEs. The GSEs play a dual antioxidant/pro-oxidant role in vivo according with the cellular antioxidant system deficiencies and exhibit cytotoxic properties in PC3 and HepG2 2.2.15 cell lines, but no antiviral action against HBV.

Estrés oxidante en asma / Oxidative stress in asthma

El asma es una enfermedad inflamatoria crónica del tracto respiratorio de etiología aún desconocida; sin embargo, nuevas evidencias han involucrado al estrés oxidante, en el que la participación e incremento en la generación de especies reactivas del oxígeno por diferentes sistemas bioquímicos, superan a los mecanismos antioxidantes en el ambiente de las vías respiratorias del asmático, lo cual es acompañado de alteraciones inducidas por radicales libres que involucran daño estructural y modificaciones metabólicas presentes, a nivel sistémico y en el tracto respiratorio.

Asthma is a chronic inflammatory disease of the airways: its precise etiology is still unknown. New evidence points to oxydative stress, in which the participation and increment of reactive species of oxygen by several biochemical systems overwhelms the anti oxidant mechanisms of the airways; this, in conjunction with changes induced by free radicals involving systemic and local respiratory structural damage and metabolic changes.