FLT3-ITD regulation of the endoplasmic reticulum functions in acute myeloid leukemia.

The FLT3-ITD mutation represents the most frequent genetic alteration in newly diagnosed acute myeloid leukemia (AML) patient and is associated with poor prognosis. Mutation result in the retention of a constitutively active form of this receptor in the endoplasmic reticulum (ER) and the subsequent modification of its downstream effectors. Here, we assessed the impact of such retention on ER homeostasis and found that mutant cells present lower levels of ER stress due to the overexpression of ERO1α, one of the main proteins of the protein folding machinery at the ER. Overexpression of ERO1α resulted essential for ITD mutant cells survival and chemoresistance and also played a crucial role in shaping the type of glucose metabolism in AML cells, being the mitochondrial pathway the predominant one in those with a higher ER stress (non-mutated cells) and the glycolytic pathway the predominant one in those with lower ER stress (mutated cells). Our data indicate that FLT3 mutational status dictates the route for glucose metabolism in an ERO1α depending on manner and this provides a survival advantage to tumors carrying these ITD mutations.

Antitumor Activity and Reductive Stress by Platinum(II) N-Heterocyclic Carbenes based on Guanosine.

Platinum(II) complexes bearing N-heterocyclic carbenes based guanosine and caffeine have been synthesized by unassisted C-H oxidative addition, leading to the corresponding trans-hydride complexes. Platinum guanosine derivatives bearing triflate as counterion or bromide instead of hydride as co-ligand were also synthesized to facilitate correlation between structure and activity. The hydride compounds show high antiproliferative activity against all cell lines (TC-71, MV-4-11, U-937 and A-172). Methyl Guanosine complex 3, bearing a hydride ligand, is up to 30 times more active than compound 4, with a bromide in the same position. Changing the counterion has no significant effect in antiproliferative activity. Increasing bulkiness at N7, with an isopropyl group (compound 6), allows to maintain the antiproliferative activity while decreasing toxicity for non-cancer cells. Compound 6 leads to an increase in endoplasmic reticulum and autophagy markers on TC71 and MV-4-11 cancer cells, induces reductive stress and increases glutathione levels in cancer cells but not in non-cancer cell line HEK-293.

Synthesis, Base Pairing Properties, and Biological Activity Studies of Platinum(II) Complexes Based on Uracil Nucleosides.

The synthesis and base pairing properties of platinum complexes based on uridine and deoxyuridine nucleosides and preliminary studies of their antiproliferative activity are described. Platinum(II) uridine and deoxyuridine complexes were synthesized by C-I oxidative addition to Pt(0)(PPh3)4. First, the synthesis was performed with protected nucleosides to generate complexes 1 and 2, which were deprotected under basic conditions, affording complexes 3 and 4 in good yields. The synthesis with the unprotected nucleosides was also performed and provided complexes 3 and 4 effectively. Base pairing interactions were measured for complex 1, either for self-base pairing or for the Watson-Crick base pair. Complex 1 undergoes self-base pairing in CDCl3, and this aggregation was found not to be dependent on metalation. Contrastingly, for the Watson-Crick base pair with adenine, base pairing was also observed, but metalation was found to affect hydrogen bonding considerably. Complexes 3 and 4 and the corresponding ligand precursors were evaluated for their antiproliferative activity against human glioblastoma cell line U-251. The compounds showed IC50 values of 3.30 (3) and 1.84 (4) µM but are also toxic for nontumorous cell lines.

Radiation as a Tool against Neurodegeneration-A Potential Treatment for Amyloidosis in the Central Nervous System.

Radiotherapy (RT) is a relatively safe and established treatment for cancer, where the goal is to kill tumoral cells with the lowest toxicity to healthy tissues. Using it for disorders involving cell loss is counterintuitive. However, ionizing radiation has a hormetic nature: it can have deleterious or beneficial effects depending on how it is applied. Current evidence indicates that radiation could be a promising treatment for neurodegenerative disorders involving protein misfolding and amyloidogenesis, such as Alzheimer's or Parkinson's diseases. Low-dose RT can trigger antioxidant, anti-inflammatory and tissue regeneration responses. RT has been used to treat peripheral amyloidosis, which is very similar to other neurodegenerative disorders from a molecular perspective. Ionizing radiation prevents amyloid formation and other hallmarks in cell cultures, animal models and pilot clinical trials. Although some hypotheses have been formulated, the mechanism of action of RT on systemic amyloid deposits is still unclear, and uncertainty remains regarding its impact in the central nervous system. However, new RT modalities such as low-dose RT, FLASH, proton therapy or nanoparticle-enhanced RT could increase biological effects while reducing toxicity. Current evidence indicates that the potential of RT to treat neurodegeneration should be further explored.

Regulation of cancer cell glucose metabolism is determinant for cancer cell fate after melatonin administration.

Several oncogenic pathways plus local microenvironmental conditions, such as hypoxia, converge on the regulation of cancer cells metabolism. The major metabolic alteration consists of a shift from oxidative phosphorylation as the major glucose consumer to aerobic glycolysis, although most of cancer cells utilize both pathways to a greater or lesser extent. Aerobic glycolysis, together with the directly related metabolic pathways such as the tricarboxylic acid cycle, the pentose phosphate pathway, or gluconeogenesis are currently considered as therapeutic targets in cancer research. Melatonin has been reported to present numerous antitumor effects, which result in a reduced cell growth. This is achieved with both low and high concentrations with no relevant side effects. Indeed, high concentrations of this indolamine reduce proliferation of cancer types resistant to low concentrations and induce cell death in some types of tumors. Previous work suggest that regulation of glucose metabolism and other related pathways play an important role in the antitumoral effects of high concentration of melatonin. In the present review, we analyze recent work on the regulation by such concentrations of this indolamine on aerobic glycolysis, gluconeogenesis, the tricarboxylic acid cycle and the pentose phosphate pathways of cancer cells.

Protein phosphatase 1 regulates huntingtin exon 1 aggregation and toxicity.

Huntington's disease is neurodegenerative disorder caused by a polyglutamine expansion in the N-terminal region of the huntingtin protein (N17). Here, we analysed the relative contribution of each phosphorylatable residue in the N17 region (T3, S13 and S16) towards huntingtin exon 1 (HTTex1) oligomerization, aggregation and toxicity in human cells and Drosophila neurons. We used bimolecular fluorescence complementation to show that expression of single phosphomimic mutations completely abolished HTTex1 aggregation in human cells. In Drosophila, mimicking phosphorylation at T3 decreased HTTex1 aggregation both in larvae and adult flies. Interestingly, pharmacological or genetic inhibition of protein phosphatase 1 (PP1) prevented HTTex1 aggregation in both human cells and Drosophila while increasing neurotoxicity in flies. Our findings suggest that PP1 modulates HTTex1 aggregation by regulating phosphorylation on T3. In summary, our study suggests that modulation of HTTex1 single phosphorylation events by PP1 could constitute an efficient and direct molecular target for therapeutic interventions in Huntington's disease.

Rituximab induces a lasting, non-cumulative remodelling of the B-cell compartment.

OBJECTIVES: Reconstitution of B-cells after their therapeutic depletion with rituximab mimics the ontogeny of the B-cell linage in patients with rheumatoid arthritis. However, little is known about the effects of multiple cycles of treatment on the repletion kinetics and their long-lasting effects on the B-cell compartment. We therefore compared the recovery capacity of the B cell subpopulations between patients who experienced their first cycle of rituximab and those who experienced successive cycles. METHODS: The distribution of the different B-cell subsets was characterised by multiparametric flow cytometry in the peripheral blood of 29 patients in the first rituximab course (naïve cycles) and 40 patients in successive cycles. Samples were obtained at baseline and at 3, 6, and 8 months of each cycle. RESULTS: The baseline percentage of B-cell subsets was similar among successive cycles. Therefore, successive cycles were grouped for comparison with naïve cycles. Patients in naïve cycles had higher percentages at baseline of both total and memory B-cells. However, the recovery of the different B-cell subsets was similar between naïve and successive cycles. In naïve patients the percentage of transitional B-cells significantly correlated with disease activity at baseline. CONCLUSIONS: Rituximab induces a long-term reshape of the B-cell compartment while multiple cycles of rituximab do not induce cumulative effects on B-cell subpopulations. Transitional B-cells seem to be associated with higher disease activity, although further studies are needed to determine if they can be used as a biomarker to predict the need for rituximab retreatment.

α-Synuclein modifies mutant huntingtin aggregation and neurotoxicity in Drosophila.

Protein misfolding and aggregation is a major hallmark of neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD). Until recently, the consensus was that each aggregation-prone protein was characteristic of each disorder [α-synuclein (α-syn)/PD, mutant huntingtin (Htt)/HD, Tau and amyloid beta peptide/AD]. However, growing evidence indicates that aggregation-prone proteins can actually co-aggregate and modify each other's behavior and toxicity, suggesting that this process may also contribute to the overlap in clinical symptoms across different diseases. Here, we show that α-syn and mutant Htt co-aggregate in vivo when co-expressed in Drosophila and produce a synergistic age-dependent increase in neurotoxicity associated to a decline in motor function and life span. Altogether, our results suggest that the co-existence of α-syn and Htt in the same neuronal cells worsens aggregation-related neuropathologies and accelerates disease progression.

Mutant huntingtin alters Tau phosphorylation and subcellular distribution.

Tau abnormalities play a central role in several neurodegenerative diseases, collectively known as tauopathies. In the present study, we examined whether mutant huntingtin (mHtt), which causes Huntington's disease (HD), modifies Tau phosphorylation and subcellular localization using cell and mouse HD models. Initially, we used novel bimolecular fluorescence complementation assays in live cells to evaluate Tau interactions with either wild type (25QHtt) or mutant huntingtin (103QHtt). While 25QHtt and Tau interacted at the level of the microtubule network, 103QHtt and Tau interacted and formed 'ring-like' inclusions localized in the vicinity of the microtubular organizing center (MTOC). Fluorescence recovery after photobleaching experiments also indicated that, whereas homomeric 103QHtt/103QHtt pairs rapidly re-entered into inclusions, heteromeric 103QHtt/Tau pairs remained excluded from the 'ring-like' inclusions. Interestingly, in vitro Tau relocalization was associated to Tau hyperphosphorylation. Consistent with this observation, we found strong Tau hyperphosphorylation in brain samples from two different mouse models of HD, R6/2 and 140CAG knock-in. This was associated with a significant reduction in the levels of Tau phosphatases (PP1, PP2A and PP2B), with no apparent involvement of major Tau kinases. Thus, the present study strongly suggests that expression of mHtt leads to Tau hyperphosphorylation, relocalization and sequestration through direct protein-protein interactions in inclusion-like compartments in the vicinity of the MTOC. Likewise, our data also suggest that Tau alterations may also contribute to HD pathogenesis.

The impact of smoking on disease activity, disability, and radiographic damage in rheumatoid arthritis: is cigarette protective?

The ojective of this study is to assess the effect of tobacco smoking on disease activity, functional ability, and joint damage in a cohort of patients with early onset rheumatoid arthritis (EORA). 129 EORA patients attending the Rheumatology Unit of the School of Medicine of the "Universidad Nacional de Colombia" and the "Clínica de Artritis y Rehabilitación" in Bogota, Colombia, were enrolled in a prospective observational cohort study with 3-year follow-up. Clinical, biological, immunogenetics, and radiographic data were analyzed. Active disease was defined as DAS28 > 2.6. Smoking status was assessed by self-report as "never smokers" and "ever smokers". Patient groups with different smoking status were compared for RA measures. Status as "never smokers" and "ever smokers" was reported by 81.3 and 18.7%. Ever smokers had less risk of disability (HAQ-DI ≥ 0.5) at 36 month (Ever smokers vs. Never smokers OR for HAQ ≥ 0.5 0.25, 95% CI 0.06-0.97, p = 0.04). When former smokers were excluded in analysis, we found that current smoking was also associated with less disability and less risk of active disease. The percentage of erosive disease, radiographic progression, and SvdH score were similar in all smoking categories. In Colombian patients with EORA, smoking was associated with less disease activity and disability. Radiographic joint damage progressed at an equivalent rate in smokers and non-smokers. These data suggest a more benign, or at least not deleterious clinical course in smokers with RA.

DJ-1 modulates aggregation and pathogenesis in models of Huntington's disease.

The oxidation-sensitive chaperone protein DJ-1 has been implicated in several human disorders including cancer and neurodegenerative diseases. During neurodegeneration associated with protein misfolding, such as that observed in Alzheimer's disease and Huntington's disease (HD), both oxidative stress and protein chaperones have been shown to modulate disease pathways. Therefore, we set out to investigate whether DJ-1 plays a role in HD. We found that DJ-1 expression and its oxidation state are abnormally increased in the human HD brain, as well as in mouse and cell models of HD. Furthermore, overexpression of DJ-1 conferred protection in vivo against neurodegeneration in yeast and Drosophila. Importantly, the DJ-1 protein directly interacted with an expanded fragment of huntingtin Exon 1 (httEx1) in test tube experiments and in cell models and accelerated polyglutamine aggregation and toxicity in an oxidation-sensitive manner. Our findings clearly establish DJ-1 as a potential therapeutic target for HD and provide the basis for further studies into the role of DJ-1 in protein misfolding diseases.

Inhibition of the STAT3 Protein by a Dinuclear Macrocyclic Complex.

A new diethylenetriamine-derived macrocycle bearing 2-methylpyridyl arms and containing m-xylyl spacers, L, was prepared, and its dinuclear copper(II) and zinc(II) complexes were used as receptors for the recognition in aqueous solution of a phosphorylated peptide derived from a sequence of the STAT3 protein. A detailed study of the acid-base behavior of L and of its complexation properties as well as of the association of the phosphorylated peptide to the receptor was carried out by potentiometry in aqueous solution at 298.2 K and I = 0.10 M in KNO3. The data revealed that the receptor forms stable associations with several protonated forms of the substrate, with constant values ranging from 3.32 to 4.25 log units. The affinity of the receptor for the phosphorylated substrate studied is higher at a pH value where the receptor is mainly in the [Cu2L](4+) form and the pY residue of the substrate is in the dianionic form (pH 6.55). These results, also supported by (31)P NMR studies, showed that the phosphopeptide is bound through the phosphoryl group in a bridging mode. Additionally, the receptor inhibited binding between active (phosphorylated) STAT3 and its target DNA sequence in a dose-dependent manner (IC50 63 ± 3.4 µM) in human nuclear extracts in vitro. Treatment of whole cells with the inhibitor revealed that it is bioactive in living cells and has oncostatic properties that could be interesting for the fight against cancer and other pathologies involving the STAT3 protein.

Oral hygiene care and the management of oral symptoms in patients with cancer in palliative care: a mixed methods systematic review protocol.

OBJECTIVE: The objective of this review is to examine the effectiveness of oral hygiene care in the management of oral symptoms in patients with cancer under specialist palliative care and the patients' experience of such symptoms and care. INTRODUCTION: Oral symptoms, such as xerostomia, mouth pain, or dysgeusia, are highly prevalent in patients with cancer under specialist palliative care. These symptoms have a negative effect on patients' quality of life. Oral hygiene care can manage oral symptoms and could be improved with a more systematized approach, adequate guidelines, and training to properly integrate oral hygiene into the care provided in specialist palliative care. INCLUSION CRITERIA: This review will consider quantitative, qualitative, and mixed methods studies on the effectiveness and experience of oral hygiene care intended to manage oral symptoms in patients with cancer aged 18 years or older, diagnosed with any type of cancer, under specialist palliative care. METHODS: The search will be conducted in MEDLINE (PubMed), CINAHL (EBSCOhost), Cochrane Central Register of Controlled Trials, Dentistry and Oral Sciences Source (EBSCOhost), and MedicLatina (EBSCOhost). Sources of unpublished studies and gray literature to be searched will include Networked Digital Library of Theses and Dissertations and Repositórios Científicos de Acesso Aberto de Portugal. Studies in English, Portuguese, and Spanish published from 2000 to the present will be considered. Methodological quality of included studies will be assessed and data will be extracted. Synthesis and integration will follow the JBI segregated approach for mixed methods reviews. REVIEW REGISTRATION: PROSPERO CRD42023400554.

Lung ultrasound score predicts outcomes in patients with acute respiratory failure secondary to COVID-19 treated with non-invasive respiratory support: a prospective cohort study.

BACKGROUND: Lung ultrasound has demonstrated its usefulness in several respiratory diseases management. One derived score, the Lung Ultrasound (LUS) score, is considered a good outcome predictor in patients with Acute Respiratory Failure (ARF). Nevertheless, it has not been tested in patients undergoing non-invasive respiratory support (NIRS). Taking this into account, the aim of this study is to evaluate LUS score as a predictor of 90-day mortality, ETI (Endotracheal intubation) and HFNC (High Flow Nasal Cannula) failure in patients with ARF due to COVID-19 admitted to a Respiratory Intermediate Care Unit (RICU) for NIRS management. RESULTS: One hundred one patients were admitted to the RICU during the study period. Among these 76% were males and the median age was 55 (45-64) years. Initial ARF management started with HFNC, the next step was the use of Continuous Positive Airway Pressure (CPAP) devices and the last intervention was ETI and Intensive Care Unit (ICU) admission. Of the total study population, CPAP was required in 40%, ETI in 26%, while 15% died. By means of a ROC analysis, a LUS ≥ 25 points was identified as the cut-off point for mortality(AUC 0.81, OR 1.40, 95% CI 1.14 to 1.71; p < 0.001), ETI (AUC 0.83, OR 1.43, 95% CI 1.20 to 1.70; p < 0.001) and HFNC failure (AUC 0.75, OR 1.25, 95% CI 1.12 to 1.41; p < 0.001). Kaplan-Meier survival curves also identified LUS ≥ 25 as a predictor of 90-days mortality (HR 4.16, 95% CI 1.27-13.6) and 30 days ETI as well. CONCLUSION: In our study, a ≥ 25 point cut-off of the Lung Ultrasound Score was identified as a good outcome prediction factor for 90-days mortality, ETI and HFNC failure in a COVID-19 ARF patients cohort treated in a RICU. Considering that LUS score is easy to calculate, a multicenter study to confirm our findings should be performed.

Mechanisms involved in the pro-apoptotic effect of melatonin in cancer cells.

It is well established that melatonin exerts antitumoral effects in many cancer types, mostly decreasing cell proliferation at low concentrations. On the other hand, induction of apoptosis by melatonin has been described in the last few years in some particular cancer types. The cytotoxic effect occurs after its administration at high concentrations, and the molecular pathways involved have been only partially determined. Moreover, a synergistic effect has been found in several cancer types when it is administered in combination with chemotherapeutic agents. In the present review, we will summarize published work on the pro-apoptotic effect of melatonin in cancer cells and the reported mechanisms involved in such action. We will also construct a hypothesis on how different cell signaling pathways may relate each other on account for such effect.

First record of the genus Ctenipocoris (Heteroptera: Naucoridae) in Central America, with a preliminary key to the American species and description of a new species.

A new naucorid species, Ctenipocoris oscari Herrera NEW SPECIES, is herein described for Costa Rica. It is the first species to be described in Central America and the sixth American species. Comparative notes are provided to differentiate this species from the others. Type material is deposited at the Zoological Museum of the University of Costa Rica (MZUCR), San José, Costa Rica. A preliminary key to the American species of the genus is provided.

Asymmetric post-translational modifications regulate the nuclear translocation of STAT3 homodimers in response to leukemia inhibitory factor.

STAT3 is a pleiotropic transcription factor overactivated in 70% of solid tumours. We have recently reported that inactivating mutations on residues susceptible to post-translational modifications (PTMs) in only one of the monomers (i.e. asymmetric) caused changes in the cellular distribution of STAT3 homodimers. Here, we used more controlled experimental conditions, i.e. without the interference of endogenous STAT3 (STAT3-/- HeLa cells) and in the presence of a defined cytokine stimulus (Leukemia Inhibitory Factor, LIF), to provide further evidence that asymmetric PTMs affect the nuclear translocation of STAT3 homodimers. Time-lapse microscopy for 20 min after LIF stimulation showed that S727 dephosphorylation (S727A) and K685 inactivation (K685R) slightly enhanced the nuclear translocation of STAT3 homodimers, while K49 inactivation (K49R) delayed STAT3 nuclear translocation. Our findings suggest that asymmetrically modified STAT3 homodimers could be a new level of STAT3 regulation and, therefore, a potential target for cancer therapy.

Cooperative action of JNK and AKT/mTOR in 1-methyl-4-phenylpyridinium-induced autophagy of neuronal PC12 cells.

Parkinson's disease has been widely related to both apoptosis and oxidative stress. Many publications relate the loss of mitochondrial potential to an apoptosis-mediated cell death in different in vivo and in vitro models of this pathology. The present study used the dopaminegic specific neurotoxin 1-methyl-4-phenylpyridinium (MPP(+) ) on neuron-like PC12 cells, which is a well-accepted model of Parkinson's disease. Results showed an early increase in oxidants, which drives the modulation of c-Jun N-terminal kinase (JNK) and AKT/mammalian target of rapamycin (mTOR) pathways, mimicking peroxide treatment. However, the cell death found in neuronal PC12 cells treated with MPP(+) was not a caspase-associated apoptosis. Electron microscopic images illustrated autophagic cell death, which was confirmed by a Beclin-1 and ATG expression increase, accumulation of acidic vesicles, and rescue by an autophagy inhibitor. In conclusion, the boost in oxidants from MPP(+) treatment in neuronal PC12 is modulating both survival (AKT/mTOR) and death (JNK) pathways, which are the perpetrators of an autophagic cell death.

The role of understudied post-translational modifications for the behavior and function of Signal Transducer and Activator of Transcription 3.

The Signal Transducer and Activator of Transcription (STAT) family of transcription factors is involved in inflammation, immunity, development, cancer, and response to injury, among other biological phenomena. Canonical STAT signaling is often represented as a 3-step pathway involving the sequential activation of a membrane receptor, an intermediate kinase, and a STAT transcription factor. The rate-limiting phosphorylation at a highly conserved C-terminal tyrosine residue determines the nuclear translocation and transcriptional activity of STATs. This apparent simplicity is actually misleading and can hardly explain the pleiotropic nature of STATs, the existence of various noncanonical STAT pathways, or the key role of the N-terminal domain in STAT functions. More than 80 post-translational modifications (PTMs) have been identified for STAT3, but their functions remain barely understood. Here, we provide a brief but comprehensive overview of these underexplored PTMs and their role on STAT3 canonical and noncanonical functions. A less tyrosine-centric point of view may be required to advance our understanding of STAT signaling.

Calcium acts as a central player in melatonin antitumor activity in sarcoma cells.

PURPOSE: Chondrosarcoma and osteosarcoma are the most frequently occurring bone cancers. Although surgery and chemotherapy are currently clinically applied, improved treatment options are urgently needed. Melatonin is known to inhibit cell proliferation in both tumor types. Although the underlying mechanisms are not clear yet, calcium homeostasis has been reported to be a key factor in cancer biology. Here, we set out to investigate whether regulation of calcium by this indolamine may be involved in its antitumor effect. METHODS: Cell viability was measured using a MTT assay and flow cytometry was used to measure levels of cytosolic calcium, intracellular oxidants, mitochondrial membrane potential and cell cycle progression. Mitochondrial calcium was analyzed by fluorimetry. Cell migration was determined using a scratch wound-healing assay. Western blot analysis was used to assess the expression of proteins related to cell cycle progression, epithelial to mesenchymal transition (EMT), Ac-CoA synthesis and intracellular signaling pathways. RESULTS: We found that melatonin decreases cytosolic and mitochondrial Ca2+ levels, intracellular oxidant levels, mitochondrial function and the expression of the E1 subunit of the pyruvate dehydrogenase complex. These changes were found to be accompanied by decreases in cell proliferation, cell migration and EMT marker expression. The addition of CaCl2 prevented the changes mentioned above, while co-treatment with the calcium chelator BAPTA enhanced the effects. CONCLUSIONS: Our data indicate that regulation of calcium homeostasis is a key factor in the inhibition of cell proliferation and migration by melatonin. This effect should be taken into consideration in combined therapies with traditional or new antitumor compounds, since it may circumvent therapy resistance.