Introduction Heart failure (HF) is characterised by an impaired heart function, several causes can lead to the development of this pathology. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) are antidiabetics that showed an important reduction of the morbimortality of patients with heart failure. However, SGLT2 is not expressed in the heart and therefore the mechanism of action inducing SGLT2i cardioprotective effects is unknown. Objective Intracellular calcium concentration being a critical regulator of cardiomyocytes (CM) contraction and thus the pump function of the heart, we explored in our study the “off-target” effect of dapagliflozin, an SGLT2i, on the regulation of calcium dynamics and its consequences on isolated cardiomyocytes contractility. Method Ventricular CM were isolated from left ventricules of 3months old healthy Wistar rats. CM were electrically field stimulated; calcium dynamic was studied using Fluo-4 calcium probe and contraction was measured by analysing sarcomeres lenght. Calcium current ICaL was measured with voltage clamp technique in whole cell configuration. Western blot technique was used to measure protein expression levels of major calcium regulators in CM. Results Our results show that dapagliflozin increases the amplitude of calcium transient while decreasing its time constant of decay. This result suggests a modulation of cytoplasmic calcium cycle, which was shown to be independent of an effect on ICaL. The increased kinetics resulted in a reduction in contraction duration. Pharmacological studies showed a significant increase (27.5±6.1%, n=12, P=0.0005) of the activity of sarcoplasmic reticulum calcium ATPase (SERCA2a) and thus an increase of the reuptake of calcium in the SR in presence of dapagliflozin. Preliminary molecular biology studies showed in dapagliflozin treated cardiomyocytes an increase of the expression of calcium/calmodulin kinase II, a key regulator of CM intracellular calcium homeostasis, as well as an increase of SERCA2a expression. Conclusion The observed increase of the calcium exchanges kinetics in CM might be responsible of the improvement of the outcome of patients with heart failure treated with dapagliflozin.
BACKGROUND AND PURPOSE:Gastrointestinal tumours overexpress voltage-gated calcium (CaV3) channels (CaV3.1, 3.2 and 3.3). CaV3 channels regulate cell growth and apoptosis colorectal cancer. Gossypol, a polyphenolic aldehyde found in the cotton plant, has anti-tumour properties and inhibits CaV3 currents. A systematic study was performed on gossypol blocking mechanism on CaV3 channels and its potential anticancer effects in colon cancer cells, which express CaV3 isoforms. EXPERIMENTAL APPROACH:Transcripts for CaV3 proteins were analysed in gastrointestinal cancers using public repositories and in human colorectal cancer cell lines HCT116, SW480 and SW620. The gossypol blocking mechanism on CaV3 channels was investigated by combining heterologous expression systems and patch-clamp experiments. The anti-tumoural properties of gossypol were estimated by cell proliferation, viability and cell cycle assays. Ca2+ dynamics were evaluated with cytosolic and endoplasmic reticulum (ER) Ca2+ indicators. KEY RESULTS:High levels of CaV3 transcripts correlate with poor prognosis in gastrointestinal cancers. Gossypol blockade of CaV3 isoforms is concentration- and use-dependent interacting with the closed, activated and inactivated conformations of CaV3 channels. Gossypol and CaV3 channels down-regulation inhibit colorectal cancer cell proliferation by arresting cell cycles at the G0/G1 and G2/M phases, respectively. CaV3 channels underlie the vectorial Ca2+ uptake by endoplasmic reticulum in colorectal cancer cells. CONCLUSION AND IMPLICATIONS:Gossypol differentially blocked CaV3 channel and its anticancer activity was correlated with high levels of CaV3.1 and CaV3.2 in colorectal cancer cells. The CaV3 regulates cell proliferation and Ca2+ dynamics in colorectal cancer cells. Understanding this blocking mechanism maybe improve cancer therapies.
Mycetoma is a neglected invasive infection endemic in tropical and subtropical regions, presenting as a chronic subcutaneous inflammatory mass that can spread to deeper structures, leading to deformities, disabilities, and potentially mortality. The current treatment of eumycetoma, the fungal form of mycetoma, involves antifungal agents, such as itraconazole, combined with surgical intervention. However, this approach has limited success, with low cure rates and a high risk of recurrence. This study addresses to the urgent need for more effective therapeutics by designing and synthesising 47 diversely pharmacomodulated imidazo [1,2-b]pyridazine derivatives using a simple synthetic pathway with good yields and purity. Of these, 17 showed promising in vitro activity against Madurella mycetomatis, the prime causative agent of eumycetoma, with IC50 <= 5 mu M and demonstrated significantly lower cytotoxicity compared to standard treatments in NIH-3T3 fibroblasts. Notably, compound 14d exhibited an excellent activity with an IC50 of 0.9 mu M, in the same order then itraconazole (IC50 = 1.1 mu M), and achieved a favourable selectivity index of 16 compared to 0.8 for itraconazole. These promising results warrant further research to evaluate the clinical potential of these novel compounds as safer, more effective treatments for eumycetoma, thus addressing a profound gap in current therapeutic strategies.
Colorectal cancer (CRC) is the second leading cause of death worldwide, with 0.9 million deaths per year. The metastatic stage of the disease is identified in about 20% of cases at the first diagnosis and is associated with low patient-survival rates. Voltage-gated sodium channels (NaV) are abnormally overexpressed in several carcinomas including CRC and are strongly associated with the metastatic behavior of cancer cells. Acidification of the extracellular space by Na+/H+ exchangers (NHE) contributes to extracellular matrix degradation and cell invasiveness. In this study, we assessed the expression levels of pore-forming α-subunits of NaV channels and NHE exchangers in tumor and adjacent non-malignant tissues from colorectal cancer patients, CRC cell lines and primary tumor cells. In all cases, SCN5A (gene encoding for NaV1.5) was overexpressed and positively correlated with cancer stage and poor survival prognosis for patients. In addition, we identified an anatomical differential expression of SCN5A and SLC9A1 (gene encoding for NHE-1) being particularly relevant for tumors that originated on the sigmoid colon epithelium. The functional activity of NaV1.5 channels was characterized in CRC cell lines and the primary cells of colon tumors obtained using tumor explant methodologies. Furthermore, we assessed the performance of two new small-molecule NaV1.5 inhibitors on the reduction of sodium currents, as well as showed that silencing SCN5A and SLC9A1 substantially reduced the 2D invasive capabilities of cancer cells. Thus, our findings show that both NaV1.5 and NHE-1 represent two promising targetable membrane proteins against the metastatic progression of CRC.
PDF file - 579K, S1. Validation of the MDA-MB-435s cell system expressing luciferase gene and expressing or not KCNN3 gene. S2. SK3 knockdown reduced the development of metastases in cancer cell xenograft models. A) SK3 knockdown reduced the metastatic score in cancer cell xenograft model. S3.Role of Orai1 in the constitutive SK3-dependent calcium entry and SK3+ cell migration. S4. Effect of Ohmline on Orai1 and SK3 expression and on constitutive calcium entry. S5. SK3 protein was expressed in smooth muscle cells of urinary bladder detrusor and myometrium and in primary tumour form mice grafted with SK3+ cells 16 weeks post grafted.
Interest for neuromodulation, and transcranial random noise stimulation (tRNS) in particular, is growing. It concerns patients rehabilitation, but also healthy people who want or need to improve their cognitive and learning abilities. However, there is no consensus yet regarding the efficacy of tRNS on learning and performing a complex task. In particular, the most effective electrode montage is yet to be determined. Here, we examined the effect of two different tRNS montages on learning rate, short- and long-term performance in a video game (Space Fortress) that engages multiple cognitive abilities. Sixty-one participants were randomly assigned to one of three groups (sham vs. simple-definition tRNS vs. high-definition tRNS) in a double-blind protocol. Their performance on the Space Fortress task was monitored during a 15-day experiment with baseline (day 1), stimulation (day 2 to 4), short- (day 5) and long-term (day 15) evaluations. Our results show that the high-definition tRNS group improved more on the long term than simple-definition tRNS group, tended to learn faster and had better performance retention compared to both simple-definition tRNS and sham groups. This study is the first to report that high-definition tRNS is more effective than conventional simple-definition tRNS to enhance performance in a complex task.
The SCN4B gene, coding for the NaVβ4 subunit of voltage-gated sodium channels, was recently found to be expressed in normal epithelial cells and down-regulated in several cancers. However, its function in normal epithelial cells has not been characterized. In this study, we demonstrated that reducing NaVβ4 expression in MCF10A non-cancer mammary epithelial cells generated important morphological changes observed both in two-dimensional cultures and in three-dimensional cysts. Most notably, the loss of NaVβ4 induced a complete loss of epithelial organisation in cysts and increased proteolytic activity towards the extracellular matrix. Loss of epithelial morphology was associated with an increased degradation of β-catenin, reduced E-cadherin expression and induction of mesenchymal markers N-cadherin, vimentin, and α-SMA expression. Overall, our results suggest that Navβ4 may participate in the maintenance of the epithelial phenotype in mammary cells and that its downregulation might be a determining step in early carcinogenesis.
Herein, we report the design, synthesis and evaluation of novel bioinspired imidazo[1,2-a:4,5c']dipyridines. The structural optimization identified four anti-proliferative compounds. Compounds 11, 18, 19 and 20 exhibited excellent anticancer activities in vitro with IC50 of 0.4-5 μM against three human cancer cell lines (MDA-MB-468, MDA-MB-435s and MDA-MB-231). These four compounds induced apoptosis in MDA-MB-231 cells in a dose-dependent manner, targeting different apoptotic proteins expression: 11 increased the expression of pro-apoptotic Bax protein while 18-20 reduced the level of anti-apoptotic Bcl-2 protein. Compounds 18 and 19 also reduced MDA-MB-231 cells proliferation as measured by Ki-67 staining. Furthermore, compounds were also tested for the ability to inhibit cell migration in the highly aggressive human MDA-MB-435s cell line. Six compounds of this series (8, 15, 18, 22, 23, 24) inhibited cell migration by 41-50% while four compounds (20, 25, 27, 30) inhibited the migration by 53-62% in wound-healing experiments. Interestingly, compound 20 presented both antiproliferative and anti-migration activities and might be a promising anti-metastatic agent for cancer treatment.
Voltage-gated sodium (Na-V) channels, initially characterized in excitable cells, have been shown to be aberrantly expressed in non-excitable cancer tissues and cells from epithelial origins such as in breast, lung, prostate, colon, and cervix, whereas they are not expressed in cognate non-cancer tissues. Their activity was demonstrated to promote aggressive and invasive potencies of cancer cells, both in vitro and in vivo, whereas their deregulated expression in cancer tissues has been associated with metastatic progression and cancer-related death. This review proposes Na-V channels as pharmacological targets for anticancer treatments providing opportunities for repurposing existing Na-V-inhibitors or developing new pharmacological and nutritional interventions.
The P2X7 receptor is an ATP-gated cation channel with a still ambiguous role in cancer progression, proposed to be either pro- or anti-cancerous, depending on the cancer or cell type in the tumour. Its role in mammary cancer progression is not yet defined. Here, we show that P2X7 receptor is functional in highly aggressive mammary cancer cells, and induces a change in cell morphology with fast F-actin reorganization and formation of filopodia, and promotes cancer cell invasiveness through both 2- and 3-dimensional extracellular matrices in vitro. Furthermore, P2X7 receptor sustains Cdc42 activity and the acquisition of a mesenchymal phenotype. In an immunocompetent mouse mammary cancer model, we reveal that the expression of P2X7 receptor in cancer cells, but not in the host mice, promotes tumour growth and metastasis development, which were reduced by treatment with specific P2X7 antagonists. Our results demonstrate that P2X7 receptor drives mammary tumour progression and represents a pertinent target for mammary cancer treatment.
The acquisition of invasive capacities by carcinoma cells, i.e. their ability to migrate through and to remodel extracellular matrices, is a determinant process leading to their dissemination and to the development of metastases. these cancer cell properties have often been associated with an increased Rho-ROCK signalling, and ROCK inhibitors have been proposed for anticancer therapies. In this study we used the selective ROCK inhibitor, Y-27632, to address the participation of the Rho-ROCK signalling pathway in the invasive properties of SW620 human colon cancer cells. Contrarily to initial assumptions, Y-27632 induced the acquisition of a pro-migratory cell phenotype and increased cancer cell invasiveness in both 3- and 2-dimensions assays. This effect was also obtained using the other ROCK inhibitor Fasudil as well as with knocking down the expression of ROCK-1 or ROCK-2, but was prevented by the inhibition of NaV1.5 voltage-gated sodium channel activity. Indeed, ROCK inhibition enhanced the activity of the pro-invasive NaV1.5 channel through a pathway that was independent of gene expression regulation. In conclusions, our evidence identifies voltage-gated sodium channels as new targets of the ROCK signalling pathway, as well as responsible for possible deleterious effects of the use of ROCK inhibitors in the treatment of cancers.
A single session of priming cathodal transcranial direct current stimulation (tDCS) prior to anodal tDCS (c-a-tDCS) allows cumulative effects on motor learning and retention. However, the impact of multiple sessions of c-a-tDCS priming on learning and retention remains unclear. Here, we tested whether multiple sessions of c-a-tDCS (over 3 consecutive days) applied over the left sensorimotor cortex can further enhance motor learning and retention of an already learned visuo-motor task as compared to anodal tDCS (a-tDCS) or sham. In a between group and randomized double-blind sham-controlled study design, 25 participants separated in 3 independent groups underwent 2 days of baseline training without tDCS followed by 3-days of training with both online and offline tDCS, and two retention tests (1 and 14 days later). Each training block consisted of five trials of a 60 s circular-tracing task intersected by 60 s rest, and performance was assessed in terms of speed–accuracy trade-off represented notably by an index of performance (IP). The main findings of this exploratory study were that multiple sessions of c-a-tDCS significantly further enhanced IP above baseline training levels over the 3 training days that were maintained over the 2 retention days, but these learning and retention performance changes were not significantly different from the sham group. Subtle differences in the changes in speed–accuracy trade-off (components of IP) between c-a-tDCS (maintenance of accuracy over increasing speed) and a-tDCS (increasing speed over maintenance of accuracy) provide preliminary insights to a mechanistic modulation of motor performance with priming and polarity of tDCS.
The aim of this study is to identify high performance thin layer chromatography (HPTLC) conditions allowing the separation and quantification of mammalian cellular phospholipids (PLs) (sphingomyelin, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, and especially phosphatidic acid, cardiolipin, and monolysocardiolipin, these latter two being specifically located in mitochondria membranes). In order to make this method faster and easier, a 1D HPTLC method is chosen, testing several eluents as well as several staining methods. A pre-conditioning of HPTLC plates with boric acid and a copper staining reagent followed by carbonization are selected for the quality of PL separation and homogeneity of staining. The selected conditions are discussed and the method validation is performed according to the International Conference on Harmonization guidelines. Linearity is effective between 1 and 8 mu g and limit of quantification is between 0.5 and 2.3 mu g depending on PL classes. Precision measurements show coefficients of variation <6%, and when amounts are close to the detection limit, Practical Applications: The changes in PL composition play a crucial role in tumor processes and regulate cellular functions modulating cellular signaling or mitochondrial metabolism. The simple and cost-effective 1D HPTLC method that is developed is applied to lipid extracts of whole tumor cells or hepatocyte-isolated mitochondria. It is sensitive as well as precise to detect variations of phosphatidic acid or cardiolipin levels linked to physio-pathological conditions. It can also be used to investigate the composition changes of other membrane PLs. Moreover, with a simultaneous analysis of 14 samples/standards on the same plate (six plates per day), this method is adapted for large series of samples.
Loss of epithelial polarity and gain in invasiveness by carcinoma cells are critical events in the aggressive progression of cancers and depend on phenotypic transition programs such as the epithelial-to-mesenchymal transition (EMT). Many studies have reported the aberrant expression of voltage-gated sodium channels (NaV) in carcinomas and specifically the NaV1.5 isoform, encoded by the SCN5A gene, in breast cancer. NaV1.5 activity, through an entry of sodium ions, in breast cancer cells is associated with increased invasiveness, but its participation to the EMT has to be clarified. In this study, we show that reducing the expression of NaV1.5 in highly aggressive human MDA-MB-231 breast cancer cells reverted the mesenchymal phenotype, reduced cancer cell invasiveness and the expression of the EMT-promoting transcription factor SNAI1. The heterologous expression of NaV1.5 in weakly invasive MCF-7 breast cancer cells induced their expression of both SNAI1 and ZEB1 and increased their invasive capacities. In MCF-7 cells the stimulation with the EMT-activator signal TGF-β1 increased the expression of SCN5A. Moreover, the reduction of the salt-inducible kinase 1 (SIK1) expression promoted NaV1.5-dependent invasiveness and expression of EMT-associated transcription factor SNAI1. Altogether, these results indicated a prominent role of SIK1 in regulating NaV1.5-dependent EMT and invasiveness.
Background and Aims: Confocal laser endomicroscopy (CLE) has been shown to predict relapse in inflammatory bowel disease, but its value in the detection of postoperative recurrence in Crohn's disease (CD) is unknown. The aims of this pilot study performed in patients with CD after ileocolonic resection were to compare the macroscopic appearance of the neoterminal ileum, according to the endoscopic Rutgeerts score, with the microscopic findings provided by CLE 6 to 12 months after surgery and to assess the predictive values of CLE-generated parameters for predicting further recurrence in patients with postoperative endoscopic remission. Methods: In 25 consecutive patients with CD within 6 to 12 months of surgery, the neoterminal ileum was examined by standard white-light endoscopy (Rutgeerts scale) followed by CLE (Watson grade). Only patients without endoscopic recurrence (Rutgeerts i0 and i1) were then followed endoscopically and clinically (median follow-up 38 months). Results: At the time of the first postoperative colonoscopy, 18 patients (72%) were in endoscopic remission, and 7 (28%) experienced an endoscopic recurrence (Rutgeerts >= i2). The Rutgeerts score was significantly correlated with the Watson score (rho = 0.73; P < .0001). The Watson scores at baseline were significantly higher in patients with further endoscopic recurrence (median 2.0; interquartile range [IQR] 1.5-2.0) than in those with endoscopic remission (median 1.0; IQR 1.0-1.0; P = .032) and were significantly higher in patients with clinical relapse (medium 2.0, IQR 2.0-2.0) compared with those in clinical remission (median 1.0; IQR 1.0-1.0; P = .036). Conclusions: CLE could be useful in monitoring patients with CD after intestinal resection. Further studies with a larger population are necessary to confirm these preliminary results.
Transcranial direct current stimulation (tDCS) is a noninvasive and portable brain stimulation technique that is ideally suited to augment human brain performance in everyday settings. The aim of this study was to measure and model the time course of bilateral cortical hemodynamics (using functional near-infrared spectroscopy, fNIRS) and neural activity (using electroencephalography, EEG) during tDCS. Subjects received real (tDCS-1 and tDCS-2) and sham anodal tDCS (2 mA) targeting the left sensorimotor cortex (SMC) via a 4 × 1 high-definition electrode montage. Simultaneous EEG (23 channels) and fNIRS (16 channels) were used to measure changes in left and right SMC activity (EEG: frequency) and hemodynamics (fNIRS: oxyhemoglobin concentrations, O2Hb) during the stimulation. The O2Hb time course showed a greater increase in the fNIRS channels surrounding the anode in the stimulated left SMC during the real tDCS sessions compared to the sham. In a subsample of five subjects, a Kalman filter using an autoregressive exogenous model was able to appropriately track O2Hb signals using EEG band-power signals. The neuronal (EEG) and hemodynamic (fNIRS) responses in the stimulated left SMC region can lend to closed-loop control of anodal tDCS for optimized neuromodulation in various neuroergonomic applications.
Functional targeting with anodal high-definition transcranial direct current stimulation (HD-atDCS) of involved brain areas during performance of a motor task (online) may facilitate sensorimotor cortex neuroplasticity compared to performing the motor task after HD-atDCS (offline). The aim of this study was to employ functional near-infrared spectroscopy to compare the time course of motor task-related changes in sensorimotor cortex activation between online and offline HD-atDCS. We hypothesized that online HD-atDCS would have a greater effect on task-related sensorimotor cortex activation than offline HD-atDCS. In a within-subject sham controlled and randomized study design, 9 healthy participants underwent 3 HD-atDCS sessions (online, offline and sham) targeting the left sensorimotor cortex separated by 1 week. Functional near-infrared spectroscopy hemodynamic changes were measured from the left sensorimotor cortex during a simple finger opposition motor task before (Pre), immediately (T1) and 30 min after (T2) each session. The movement rates were not different between (online, offline, sham) or within (Pre, T1, T2) sessions. At T2, online HD-atDCS was associated with a significant increase (large effect size) in sensorimotor cortex activation (Hedges g = 1.01, p < 0.001) when compared to sham; there was a nonsignificant trend to increase activation between offline and sham (Hedges g = 0.52, p = 0.05) and between online and offline (Hedges g = 0.53, p = 0.06). Concurrent application of HD-atDCS during a motor task may produce larger sensorimotor cortex activation than sequential application.
Metabolic reprogramming in tumours is now recognized as a hallmark of cancer, participating both in tumour growth and cancer progression. Cancer cells develop global metabolic adaptations allowing them to survive in the low oxygen and nutrient tumour microenvironment. Among these metabolic adaptations, cancer cells use glycolysis but also mitochondrial oxidations to produce ATP and building blocks needed for their high proliferation rate. Another particular adaptation of cancer cell metabolism is the use of autophagy and specific forms of autophagy like mitophagy to recycle intracellular components in condition of metabolic stress or during anticancer treatments. The plasticity of cancer cell metabolism is a major limitation of anticancer treatments and could participate to therapy resistances. The aim of this review is to report recent advances in the understanding of the relationship between tumour metabolism and autophagy/mitophagy in order to propose new therapeutic strategies.
Online transcranial direct current stimulation (i.e., tDCS concurrent to the task) and priming tDCS are proposed to have cumulative effects on motor performance. However, the impact of the tDCS polarity for priming remains unclear. The aim of this study was to enhance more motor learning and retention of a motor task with multiple online anodal tDCS (atDCS) sessions using cathodal tDCS (ctDCS) priming as compared to atDCS or sham. In a double blind randomized and sham controlled study design, 22 participants separated in 3 independent groups underwent for 3 consecutive days high definition-atDCS (20 min, 2 mA) training sessions targeting the left sensorimotor cortex, preceded by a baseline measurement (d0) and followed by two retention tests (d4 and d18, one day and two weeks after training, respectively). A circular tracing-movement task of 5 trials of 1 min intersected by 1 min rest was performed at pre-, during and post- atDCS for each training session and for d0, d4 and d18. The motor performance increased significantly at the end of training (d3) for both atDCS and ctDCS priming (P < 0.001) but not for sham. This increase was also observed at d4 for atDCS (P = 0.05) and for ctDCS at d4 and d18 (P < 0.001). The combination of priming tDCS and multiple sessions of motor task-concurrent anodal tDCS was beneficial for improving performance during and after training without being superior to sham. The cumulative effects of priming with training persisted only for ctDCS priming two weeks after the end of the training.
Understanding the interactions between brain activity and behavior comprehensively in achieving optimal exercise performance in sports is still lacking. The existent research in this area has been limited by the constraints of sports environments and the robustness of the most suitable non-invasive functional neuroimaging methods (electroencephalography, EEG and functional near-infrared spectroscopy, fNIRS) to motion artifacts and noise. However, recent advances in brain mapping technology should improve the capabilities of the future brain imaging devices to assess and monitor the level of adaptive cognitive-motor performance during exercise in sports environments. The purpose of this position manuscript is to discuss the contributions and issues in behavioral neuroscience related to brain activity measured during exercise and in various sports. A first part aims to give an overview of EEG and fNIRS neuroimaging methods assessing electrophysiological activity and hemodynamic responses of the acute and chronic relation of physical exercise on the human brain. Then, methodological issues, such as the reliability of brain data during physical exertion, key limitations and possible prospects of fNIRS and EEG methods are provided. While the use of such methods in sports environments remains scarce and limited to controlled cycling task, new generation of wearable, whole-scalp EEG and fNIRS technologies could open up a range of new applications in sports sciences for providing neuroimaging-based biomarkers (hemodynamic and/or neural electrical signals) to various types of exercise and innovative training.