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The energetic metabolism of cancer cells relies on a substantial commitment of pyruvate to the catalytic action of lactate‐generating dehydrogenases. This coupling mainly depends on lactate dehydrogenase A (LDH‐A), which is overexpressed in different types of cancers, and therefore represents an appealing therapeutic target. Taking into account that the activity of LDHs is exclusively exerted by their tetrameric forms, it was recently shown that peptides perturbing the monomers‐to‐tetramer assembly inhibit human LDH‐A (hLDH‐A). However, to identify these peptides, tetrameric hLDH‐A was transiently exposed to strongly acidic conditions inducing its dissociation into monomers, which were tested as a target for peptides at low pH. Nevertheless, the availability of native monomeric hLDH‐A would allow performing similar screenings under physiological conditions. Here we report on the unprecedented isolation of recombinant monomeric hLDH‐A at neutral pH, and on its use to identify peptides inhibiting the assembly of the tetrameric enzyme. Remarkably, the GQNGISDL octapeptide, mimicking the 296–303 portion of hLDH‐A C‐terminal region, was observed to effectively inhibit the target enzyme. Moreover, by dissecting the action of this octapeptide, the cGQND cyclic tetrapeptide was found to act as the parental compound. Furthermore, we performed assays using MCF7 and BxPC3 cultured cells, exclusively expressing hLDH‐A and hLDH‐B, respectively. By means of these assays we detected a selective action of linear and cyclic GQND tetrapeptides, inhibiting lactate secretion in MCF7 cells only. Overall, our observations suggest that peptides mimicking the C‐terminal region of hLDH‐A effectively interfere with protein–protein interactions responsible for the assembly of the tetrameric enzyme. [ABSTRACT FROM AUTHOR]

Cancer cells can release EGF-like peptides, acquiring the capacity of autocrine stimulation via EGFR-mediated signaling. One of these peptides (HBEGF) was found to be released from a membrane-bound precursor protein and is critically implicated in the proliferative potential of cancer cells. We observed that the increased lactate levels characterizing neoplastic tissues can induce the release of uPA, a protease promoting HBEGF shedding. This effect led to EGFR activation and increased ERK1/2 phosphorylation. Since EGFR-mediated signaling potentiates glycolytic metabolism, this phenomenon can induce a self-sustaining deleterious loop, favoring tumor growth. A well characterized HBEGF inhibitor is CRM197, a single-site variant of diphtheria toxin. We observed that, when administered individually, CRM197 did not trigger evident antineoplastic effects. However, its association with a uPA inhibitor caused dampening of EGFR-mediated signaling and apoptosis induction. Overall, our study highlights that the increased glycolytic metabolism and lactate production can foster the activated state of EGFR receptor and suggests that the inhibition of EGFR-mediated signaling can be attempted by means of CRM197 administered with an appropriate protease inhibitor. This attempt could help in overcoming the problem of the acquired resistance to the conventionally used EGFR inhibitors. [ABSTRACT FROM AUTHOR]

Simple Summary: Cancer cells are characterized by massive glucose consumption, leading to increased lactate generation. Once considered a waste product, this metabolite was recently shown to take part in the regulation of gene expression. The regulatory properties of lactate were also found to play a role in fostering drug resistance. In this paper, we examined whether the exposure of cancer cells to increased lactate levels can affect the anticancer efficacy of doxorubicin. Doxorubicin is a widely used drug, whose clinical application is often hampered by severe cardiotoxicity. We found that lactate can offer protection against oxidative damage caused by the drug. Interestingly, oxidative damage is reputed secondary to the antineoplastic action of the drug but plays an important role in mediating its cardiotoxic effects. Background: Doxorubicin (DOXO) is currently administered as the first-choice therapy for a variety of malignancies. Cancer cells exhibit enhanced glycolysis and lactate production. This metabolite affects gene expression and can play a role in chemoresistance. Aim of this study: We investigated whether the enhanced lactate levels that characterize neoplastic tissues can modify the response of cancer cells to DOXO. Methods: After exposing cancer cells to increased lactate levels, we examined whether this metabolite could interfere with the principal mechanisms responsible for the DOXO antineoplastic effect. Results: Increased lactate levels did not affect DOXO-induced topoisomerase poisoning but offered protection against the oxidative damage caused by the drug. This protection was related to changes in gene expression caused by the combined action of DOXO and lactate. Oxidative damage significantly contributed to the heavy cardiotoxicity following DOXO treatment. In cultured cardiomyocytes, we confirmed that DOXO-induced DNA damage and oxidative stress can be significantly mitigated by exposing the cells to increased lactate levels. Conclusions: In addition to contributing to elucidating the effects of the combined action of DOXO and lactate, our results suggest a possible method to reduce the heavy drug cardiotoxicity, a major side effect leading to therapy discontinuation. [ABSTRACT FROM AUTHOR]

Background: Balance impairment is a common disability in post-stroke survivors, leading to reduced mobility and increased fall risk. Robotic gait training (RAGT) is largely used, along with traditional training. There is, however, no strong evidence about RAGT superiority, especially on balance. This study aims to determine RAGT efficacy on balance of post-stroke survivors. Methods: PubMed, Cochrane Library, and PeDRO databases were investigated. Randomized clinical trials evaluating RAGT efficacy on post-stroke survivor balance with Berg Balance Scale (BBS) or Timed Up and Go test (TUG) were searched. Meta-regression analyses were performed, considering weekly sessions, single-session duration, and robotic device used. Results: A total of 18 trials have been included. BBS pre-post treatment mean difference is higher in RAGT-treated patients, with a pMD of 2.17 (95% CI 0.79; 3.55). TUG pre-post mean difference is in favor of RAGT, but not statistically, with a pMD of −0.62 (95%CI − 3.66; 2.43). Meta-regression analyses showed no relevant association, except for TUG and treatment duration (β = −1.019, 95% CI − 1.827; −0.210, p-value = 0.0135). Conclusions: RAGT efficacy is equal to traditional therapy, while the combination of the two seems to lead to better outcomes than each individually performed. Robot-assisted balance training should be the focus of experimentation in the following years, given the great results in the first available trials. Given the massive heterogeneity of included patients, trials with more strict inclusion criteria (especially time from stroke) must be performed to finally define if and when RAGT is superior to traditional therapy. [ABSTRACT FROM AUTHOR]

The cytotoxic action of anticancer drugs can be potentiated by inhibiting DNA repair mechanisms. RAD51 is a crucial protein for genomic stability due to its critical role in the homologous recombination (HR) pathway. BRCA2 assists RAD51 fibrillation and defibrillation in the cytoplasm and nucleus and assists its nuclear transport. BRC4 is a peptide derived from the fourth BRC repeat of BRCA2, and it lacks the nuclear localization sequence. Here, we used BRC4 to (i) reverse RAD51 fibrillation; (ii) avoid the nuclear transport of RAD51; and (iii) inhibit HR and enhance the efficacy of chemotherapeutic treatments. Specifically, using static and dynamic light scattering, transmission electron microscopy, and microscale thermophoresis, we show that BRC4 eroded RAD51 fibrils from their termini through a "domino" mechanism and yielded monomeric RAD51 with a cumulative nanomolar affinity. Using cellular assays (BxPC-3, pancreatic cancer), we show that a myristoylated BRC4 (designed for a more efficient cell entry) abolished the formation of nuclear RAD51 foci. The present study provides a molecular description of RAD51 defibrillation, an essential step in BRCA2-mediated homologous recombination and DNA repair. [ABSTRACT FROM AUTHOR]

Abstract Background Alzheimer’s disease (AD) is one of the most frequent cause of neurodegenerative disorder in the elderly. Inflammation has been implicated in brain degenerative processes and peripheral markers of brain AD related impairment would be useful. Plasma levels of alpha-1-antichymotrypsin (ACT), an acute phase protein and a secondary component of amyloid plaques, are often increased in AD patients and high blood ACT levels correlate with progressive cognitive deterioration. During inflammatory responses changes in the micro-heterogeneity of ACT sugar chains have been described. Methods N-Glycanase digestion from Flavobacterium meningosepticum (PNGase F) was performed on both native and denatured purified ACT condition and resolved to Western blot with the purpose to revealed the ACT de-glycosylation pattern. Further characterization of the ACT glycan profile was obtained by a glycoarray; each lectin group in the assay specifically recognizes one or two glycans/epitopes. Lectin-bound ACT produced a glyco-fingerprint and mayor differences between AD and controls samples were assessed by a specific algorithms. Results Western blot analysis of purified ACT after PNGase F treatment and analysis of sugar composition of ACT showed significantly difference in “glyco-fingerprints” patterns from controls (CTR) and AD; ACT from AD showing significantly reduced levels of sialic acid. A difference in terminal GlcNac residues appeared to be related with progressive cognitive deterioration. Conclusions Low content of terminal GlcNac and sialic acid in peripheral ACT in AD patients suggests that a different pattern of glycosylation might be a marker of brain inflammation. Moreover ACT glycosylation analysis could be used to predict AD clinical progression and used in clinical trials as surrogate marker of clinical efficacy.

The aerobic energetic metabolism of eukaryotic cells relies on the glycolytic generation of pyruvate, which is subsequently channelled to the oxidative phosphorylation taking place in mitochondria. However, under conditions limiting oxidative phosphorylation, pyruvate is coupled to alternative energetic pathways, e.g. its reduction to lactate catalyzed by lactate dehydrogenases (LDHs). This biochemical process is known to induce a significant decrease in cytosolic pH, and is accordingly denoted lactic acidosis. Nevertheless, the mutual dependence of LDHs action and lactic acidosis is far from being fully understood. Using human LDH-A, here we show that when exposed to acidic pH this enzyme is subjected to homotropic allosteric transitions triggered by pyruvate. Conversely, human LDH-A features Michaelis-Menten kinetics at pH values equal to 7.0 or higher. Further, citrate, isocitrate, and malate were observed to activate human LDH-A, both at pH 5.0 and 6.5, with citrate and isocitrate being responsible for major effects. Dynamic light scattering (DLS) experiments revealed that the occurrence of allosteric kinetics in human LDH-A is mirrored by a consistent dissociation of the enzyme tetramer, suggesting that pyruvate promotes tetramer association under acidic conditions. Finally, using the human liver cancer cell line HepG2 we isolated cells featuring cytosolic pH equal to 7.3 or 6.5, and we observed a concomitant decrease in cytosolic pH and lactate secretion. Overall, our observations indicate the occurrence of a negative feedback between lactic acidosis and human LDH-A activity, and a complex regulation of this feedback by pyruvate and by some intermediates of the Krebs cycle. [ABSTRACT FROM AUTHOR]

mTOR kinase and the A isoform of lactate dehydrogenase (LDH-A) are key players controlling the metabolic characteristics of cancer cells. By using cultured human breast cells as a “metabolic tumor” model, we attempted to explore the correlation between these two factors. “Metabolic tumors” are defined as neoplastic conditions frequently associated with features of the metabolic syndrome, such as hyper-insulinemia and hyper-glycemia. MCF-7 cells (a well differentiated carcinoma) and MCF-10A cells (a widely used model for studying normal breast cell transformation) were used in this study. These cells were exposed to known factors triggering mTOR activation. In both treated cultures, we evaluated the link between mTOR kinase activity and the level of LDH expression / function. Furthermore, we elaborated the metabolic changes produced in cells by the mTOR-directed LDH-A up-regulation. Interestingly, we observed that in the non-neoplastic MCF-10A culture, mTOR-directed up-regulation of LDH-A was followed by a reprogramming of cell metabolism, which showed an increased dependence on glycolysis rather than on oxidative reactions. As a consequence, lactate production appeared to be enhanced and cells began to display increased self-renewal and clonogenic power: signals suggestive of neoplastic change. Enhanced clonogenicity of cells was abolished by rapamycin treatment, and furthermore heavily reduced by LDH enzymatic inhibition. These results highlighted a mechanistic link between metabolic alterations and tumorigenesis, whereby suggesting LDH inhibition as a possible chemo-preventive measure to target the metabolic alterations driving neoplastic change. [ABSTRACT FROM AUTHOR]

Background: Polypharmacy and potentially inappropriate medications (PIMs) are known to affect several negative outcomes in older patients. However, studies comparatively assessing polypharmacy and PIMs in relation to readmission are distinctively lacking.Aims: To compare the impact of polypharmacy and PIMs on 3-month readmission among older patients discharged from acute care hospital.Methods: Our series consisted of 647 patients consecutively enrolled in a multicenter observational study. The outcome of the study was the occurrence of any admission during the 3-month follow-up after discharge. Polypharmacy was defined as use of more than eight medications. PIMs were identified using 2015 version of Beers and Screening Tool of Older Persons Prescriptions (STOPP) criteria. Statistical analysis was performed using logistic regression models.Results: After adjusting for potential confounders, polypharmacy (OR 2.72, 95% CI 1.48-4.99) was found associated with the outcome, while Beers (OR 0.85, 95% CI 0.46-1.56), STOPP (OR 1.60, 95% CI 0.85-3.01), or combined Beers and STOPP violations (OR 0.99, 95% CI 0.57-1.74) were not. The association between polypharmacy and 3-month readmission was confirmed in logistic regression models including Beers (OR 2.88, 95% CI 1.55-5.34), STOPP (OR 2.64, 95% CI 1.43-4.87), or combined Beers and STOPP violations (OR 2.80, 95% CI 1.51-5.21).Discussion: Besides confirming that polypharmacy should be considered as a marker for readmission risk among older patients discharged from acute care hospital, our findings suggest that the association between polypharmacy and 3-month readmission is substantially independent of use of PIMs.Conclusions: Polypharmacy, but not PIMs was significantly associated with readmission. Hospitalization should always be considered as a clue to individuate unnecessary polypharmacy and to reduce the burden of medications whenever possible. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) represents one major health concern for our growing elderly population. It accounts for increasing impairment of cognitive capacity followed by loss of executive function in late stage. AD pathogenesis is multifaceted and difficult to pinpoint, and understanding AD etiology will be critical to effectively diagnose and treat the disease. An interesting hypothesis concerning AD development postulates a cause-effect relationship between accumulation of mitochondrial DNA (mtDNA) mutations and neurodegenerative changes associated with this pathology. Here we propose a computerized method for an easy and fast mtDNA mutations-based characterization of AD. The method has been built taking into account the complexity of living being and fractal properties of many anatomic and physiologic structures, including mtDNA. Dealing with mtDNA mutations as gaps in the nucleotide sequence, fractal lacunarity appears a suitable tool to differentiate between aging and AD. Therefore, Chaos Game Representation method has been used to display DNA fractal properties after adapting the algorithm to visualize also heteroplasmic mutations. Parameter β from our fractal lacunarity method, based on hyperbola model function, has been measured to quantitatively characterize AD on the basis of mtDNA mutations. Results from this pilot study to develop the method show that fractal lacunarity parameter β of mtDNA is statistically different in AD patients when compared to age-matched controls. Fractal lacunarity analysis represents a useful tool to analyze mtDNA mutations. Lacunarity parameter β is able to characterize individual mutation profile of mitochondrial genome and appears a promising index to discriminate between AD and aging. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD) is common in older adults, and its burden is expected to increase in older populations. Even if the knowledge on the approach to older patient with CKD is still evolving, current guidelines for pharmacological management of CKD does not include specific recommendations for older patients. Additionally, decision-making on renal replacement therapy (RRT) for older patients is far from being evidence-based, and despite the improvement in dialysis outcomes, RRT may cause more harm than benefit compared with conservative care when prognostic stratification is not carefully assessed. The use of comprehensive geriatric assessment tools could help clinicians in applying a more informed decision-making. Finally, physical exercise and rehabilitation interventions also represents a promising therapeutic strategy. [ABSTRACT FROM PUBLISHER]

Abstract Objective: to evaluate whether oral supplementation with zinc or zinc/arginine increases the antibody response to influenza vaccine or modulates the lymphocyte phenotype in elderly subjects. Design: a randomized controlled [...]