Mitochondrial dysfunction promotes the transition of precursor to terminally exhausted T cells through HIF-1α-mediated glycolytic reprogramming

T cell exhaustion is a hallmark of cancer and persistent infections, marked by inhibitory receptor upregulation, diminished cytokine secretion, and impaired cytolytic activity. Terminally exhausted T cells are steadily replenished by a precursor population (Tpex), but the metabolic principles governing Tpex maintenance and the regulatory circuits that control their exhaustion remain incompletely understood. Using a combination of gene-deficient mice, single-cell transcriptomics, and metabolomic analyses, we show that mitochondrial insufficiency is a cell-intrinsic trigger that initiates the functional exhaustion of T cells. At the molecular level, we find that mitochondrial dysfunction causes redox stress, which inhibits the proteasomal degradation of hypoxia-inducible factor 1α (HIF-1α) and promotes the transcriptional and metabolic reprogramming of Tpex cells into terminally exhausted T cells. Our findings also bear clinical significance, as metabolic engineering of chimeric antigen receptor (CAR) T cells is a promising strategy to enhance the stemness and functionality of Tpex cells for cancer immunotherapy.

Characterization of the effect of the GLUT-1 inhibitor BAY-876 on T cells and macrophages

Increased aerobic glycolysis is a metabolic hallmark of proinflammatory leukocytes including macrophages and T cells. To take up glucose from the environment and fuel glycolysis, activated leukocytes upregulate the glucose transporter GLUT1. The orally bioavailable selective GLUT1 inhibitor BAY-876 was developed primarily as an anti-tumor drug. Our study assessed its activity on activated macrophages and CD4⁺ T cells. BAY-876 significantly attenuated glucose uptake by cultured CD4⁺ T cells and macrophages by 41% and 15%, respectively. Extracellular flux analysis of activated CD4⁺ T cells in vitro showed that BAY-876 significantly decreases glycolytic proton flux rate and lactate production, effects that are accompanied by an increased oxidative phosphorylation-mediated ATP production rate, leaving intracellular ATP levels per cell unchanged. However, GLUT1 inhibition reduced CD4⁺ T cell proliferation without compromising cell viability and reduced IFN-γ secretion by 20%. Moreover, TNF secretion from macrophages was reduced by 27%. We conclude that GLUT1-specific inhibitors, like BAY-876, deserve further in vivo testing in a broad range of (auto-) inflammatory disease models.

Cellular density and variability in laryngeal and pharyngeal squamous cell carcinoma using confocal laser endomicroscopy

OBJECTIVE

Confocal laser endomicroscopy (CLE) allows the visualization of epithelium in a thousand-fold magnification. This study analyzes the architectural differences at the cellular level of the mucosa and squamous cell carcinoma (SCC).

PATIENTS AND METHODS

A total of 60 CLE sequences recorded in 5 patients with SCC undergoing laryngectomy between October 2020 and February 2021 were analyzed. The corresponding histologic sample derived from H&E staining was assigned to each sequence, capturing CLE images of the tumor and healthy mucosa. In addition, the cellular structure analysis was performed to diagnose SCC by measuring the total number of cells and cell size in 60 sequences in a fixed field of view (FOV) with 240 μm in diameter (45,239 μm2).

RESULTS

Out of 3,600 images, 1,620 (45%) showed benign mucosa and 1,980 (55%) SCC. The automated analysis yielded a difference in cell size, with healthy epithelial cells being 171.9±82.0 μm2 smaller than SCC cells, which were 246.3±171.9 μm2 and showed greater variability in size (p=0.037). In addition, due to the probe's fixed FOV, there was a difference in cell count with a total of 188.7±38.3 and 124.8±38.6 cells in images of normal epithelium and SCC (p<0.001), respectively. Regarding cell density as a criterion for the differentiation of benign/malign, using a cut-off value of 145.5 cells/FOV, we obtained sensitivity and specificity of 88.0% and 71.9%, respectively.

CONCLUSIONS

SCC reveals marked differences at a cellular level compared to the healthy epithelium. Our results further support the importance of this feature for identifying SCC during CLE imaging.

CT analysis of left ventricular function predicts short term survival in patients following transcatheter aortic valve implantation: 1-year outcome data

Introduction

Contrast-enhanced cardiac CT routinely performed prior to transcatheter aortic valve implantation (TAVI), allows assessment of cardiac morphology and function. We assessed left ventricular function in CT as a predictor of survival following TAVI.

Methods

500 consecutive patients referred for CT assessment of aortic root anatomy prior to TAVI were screened for inclusion in this analysis. All CT data sets were acquired using a third-generation dual source system. For assessment of aortic root anatomy, acquisitions were acquired using ECG-gated retrospective spiral acquisition and multiphase reconstructions in 10% increments of the cardiac cycle were rendered (slice thickness 0.75, increment 0.4 mm). left ventricular endocardial contours were automatically traced by a dedicated software (syngo. via, Siemens Healthineers, Forchheim, Germany) throughout the cardiac cycle and manually adjusted if required. Global left ventricular function parameters (end-diastolic and end-systolic volumes, stroke volume, cardiac output and ejection fraction) were derived by volumetric assessment.

Results

Out of 500 patients, 439 patients (mean age 80±6 years, 56% males, and Log EuroScore 23±14%) were included in this analysis (61 patients were excluded due to poor CT image quality or missing outcome data). Previous cardiac surgery had been performed in 15% of the patients, 50% had obstructive CAD with previous interventional or surgical revascularisation and 18% had a previous acute coronary syndrome. One-year survival was 83% (366/439 patients). Parameters of left ventricular function were as follows: mean LVEDV 172±56 ml, mean LVESV 78±62 ml, mean LV ejection fraction 59±18%, mean LV stroke volume index 51±22 ml/m2, mean LV cardiac output 6.6±3.3 L/min and LV cardiac index 3.5±1.7 l/min/m2. Cluster analysis of multiple LV-function surrogate parameters identified a group of patients with higher 1-year mortality, with LVEF identified as a predictor of 1-year survival with a cut-0ff of ≥37% associated with an OR 0f 0.52 (95% CI 0.27 to 0.98).

Conclusion

Assessment of left ventricular function using functional CT data sets is feasible and allows risk stratification of patients following TAVI. Among LV functional parameters, CT derived LV-ejection fraction with a cut-off ≥37% identifies patients with better short-term outcome.

Funding Acknowledgement

Type of funding sources: None.

F18-FDG PET/CT imaging early predicts pathologic complete response to induction chemoimmunotherapy of locally advanced head and neck cancer: preliminary single-center analysis of the checkrad-cd8 trial

Aim

In the CheckRad-CD8 trial patients with locally advanced head and neck squamous cell cancer are treated with a single cycle of induction chemo-immunotherapy (ICIT). Patients with pathological complete response (pCR) in the re-biopsy enter radioimmunotherapy. Our goal was to study the value of F-18-FDG PET/CT in the prediction of pCR after induction therapy.

Methods

Patients treated within the CheckRad-CD8 trial that additionally received FDG- PET/CT imaging at the following two time points were included: 3–14 days before (pre-ICIT) and 21–28 days after (post-ICIT) receiving ICIT. Tracer uptake in primary tumors (PT) and suspicious cervical lymph nodes (LN +) was measured using different quantitative parameters on EANM Research Ltd (EARL) accredited PET reconstructions. In addition, mean FDG uptake levels in lymphatic and hematopoietic organs were examined. Percent decrease (Δ) in FDG uptake was calculated for all parameters. Biopsy of the PT post-ICIT acquired after FDG-PET/CT served as reference. The cohort was divided in patients with pCR and residual tumor (ReTu).

Results

Thirty-one patients were included. In ROC analysis, ΔSUVmax PT performed best (AUC = 0.89) in predicting pCR (n = 17), with a decline of at least 60% (sensitivity, 0.77; specificity, 0.93). Residual SUVmax PT post-ICIT performed best in predicting ReTu (n = 14), at a cutpoint of 6.0 (AUC = 0.91; sensitivity, 0.86; specificity, 0.88). Combining two quantitative parameters (ΔSUVmax ≥ 50% and SUVmax PT post-ICIT ≤ 6.0) conferred a sensitivity of 0.81 and a specificity of 0.93 for determining pCR. Background activity in lymphatic organs or uptake in suspected cervical lymph node metastases lacked significant predictive value.

Conclusion

FDG-PET/CT can identify patients with pCR after ICIT via residual FDG uptake levels in primary tumors and the related changes compared to baseline. FDG-uptake in LN + had no predictive value.

Trial registry

ClinicalTrials.gov identifier: NCT03426657.

Genetic Ablation of the Mitochondrial Calcium Uniporter (MCU) Does not Impair T Cell-Mediated Immunity In Vivo

T cell activation and differentiation is associated with metabolic reprogramming to cope with the increased bioenergetic demand and to provide metabolic intermediates for the biosynthesis of building blocks. Antigen receptor stimulation not only promotes the metabolic switch of lymphocytes but also triggers the uptake of calcium (Ca²⁺) from the cytosol into the mitochondrial matrix. Whether mitochondrial Ca²⁺ influx through the mitochondrial Ca²⁺ uniporter (MCU) controls T cell metabolism and effector function remained, however, enigmatic. Using mice with T cell-specific deletion of MCU, we here show that genetic inactivation of mitochondrial Ca²⁺ uptake increased cytosolic Ca²⁺ levels following antigen receptor stimulation and store-operated Ca²⁺ entry (SOCE). However, ablation of MCU and the elevation of cytosolic Ca²⁺ did not affect mitochondrial respiration, differentiation and effector function of inflammatory and regulatory T cell subsets in vitro and in animal models of T cell-mediated autoimmunity and viral infection. These data suggest that MCU-mediated mitochondrial Ca²⁺ uptake is largely dispensable for murine T cell function. Our study has also important technical implications. Previous studies relied mostly on pharmacological inhibition or transient knockdown of mitochondrial Ca²⁺ uptake, but our results using mice with genetic deletion of MCU did not recapitulate these findings. The discrepancy of our study to previous reports hint at compensatory mechanisms in MCU-deficient mice and/or off-target effects of current MCU inhibitors.

The COVID-19 pandemic and its consequences for the diagnosis and therapy of head and neck malignancies

OBJECTIVE

The COVID-19 pandemic and the measures accompanying it have been accused of having a negative influence on the frequency and methods of treatment of various diseases including head and neck cancer (HNSCC). To go further into this assumption, the diagnoses made, and treatments performed at one of Germany's largest head and neck cancer centres were evaluated.

PATIENTS AND METHODS

This study consisted of one single centre and involved a retrospective review of all patients with newly diagnosed or recurrent HNSCC. The diagnosis and treatment methods used in the pre-COVID-19 time period between March 1st, 2019, and March 1st, 2020, were analysed and compared with the COVID-19 time period from April 1st, 2020, until April 1st, 2021. The primary objective was defined as the number of malignant diagnoses and the secondary objectives as the disease stage and the time to therapy.

RESULTS

A total of 612 patients (160♀; mean 63 yrs.) were included. 319 patients (52%) were treated in the pre-COVID-19 time. The two groups did not differ in terms of age (p=0.304), gender (p=0.941), presence of recurrent disease (p=0.866), tumour subsite (p=0.194) or the duration from presentation to the multidisciplinary tumour board until start of therapy (p=0.202). There were no significant differences in the T stage (p=0.777), N stage (p=0.067) or UICC stage (p=0.922). During the pre-COVID-19 period more patients presented with distant metastases (n= 23 vs. n=8; p=0.011).

CONCLUSIONS

This study shows that there was no significant change in either the number and severity of HNSCC diagnoses or the time until start of therapy at this large head and neck cancer centre as a result of the COVID-19 pandemic.

Neoadjuvant concurrent chemoradiotherapy with and without hyperthermia in retroperitoneal sarcomas: feasibility, efficacy, toxicity, and long-term outcome

Purpose

Retroperitoneal (RPS) sarcomas are associated with poor local and abdominal tumor control. However, the benefit of preoperative radio- or chemotherapy alone for these entities is currently unclear. Moreover, as intermediate- and high-grade sarcomas have a tendency toward early metastasis, exploration of neoadjuvant strategies is of high importance. This analysis reports the results of our 20-year single-institution experience with preoperative neoadjuvant concurrent chemoradiation.

Methods

From 2000–2019, 27 patients with intermediate- or high-grade RPS (12 dedifferentiated liposarcoma, 10 leiomyosarcoma, 5 others) were treated with radiotherapy (median dose: 50.4 Gy; range 45–75 Gy) and two cycles of chemotherapy (doxorubicin 50 mg/m² BSA/d3 q28 and ifosfamide 1.5 g/m² BSA/d1‑5 q28) in neoadjuvant intent. Chemotherapy consisted of doxorubicin alone in two cases and ifosfamide alone in one case. Fifteen patients (56%) additionally received deep regional hyperthermia.

Results

The median follow-up time was 53 months (±56.7 months). 92% of patients received two cycles of chemotherapy as planned and 92% underwent surgery. At 5 and 10 years, abdominal-recurrence-free survival was 74.6% (±10.1%) and 66.3% (±11.9%), distant metastasis-free survival was 67.2% (±9.7%) and 59.7% (±11.1%), and overall survival was 60.3% (±10.5%) and 60.3% (±10.5%), respectively. CTC grade III and IV toxicities were leukocytopenia (85%), thrombocytopenia (33%), and anemia (11%). There were no treatment-related deaths.

Conclusion

Neoadjuvant chemoradiotherapy with and without hyperthermia for retroperitoneal sarcomas is feasible and provided high local control of intermediate- and high-grade sarcoma.

MiR-205-driven downregulation of cholesterol biosynthesis through SQLE-inhibition identifies therapeutic vulnerability in aggressive prostate cancer

Prostate cancer (PCa) shows strong dependence on the androgen receptor (AR) pathway. Here, we show that squalene epoxidase (SQLE), an enzyme of the cholesterol biosynthesis pathway, is overexpressed in advanced PCa and its expression correlates with poor survival. SQLE expression is controlled by micro-RNA 205 (miR-205), which is significantly downregulated in advanced PCa. Restoration of miR-205 expression or competitive inhibition of SQLE led to inhibition of de novo cholesterol biosynthesis. Furthermore, SQLE was essential for proliferation of AR-positive PCa cell lines, including abiraterone or enzalutamide resistant derivatives, and blocked transactivation of the AR pathway. Inhibition of SQLE with the FDA approved antifungal drug terbinafine also efficiently blocked orthotopic tumour growth in mice. Finally, terbinafine reduced levels of prostate specific antigen (PSA) in three out of four late-stage PCa patients. These results highlight SQLE as a therapeutic target for the treatment of advanced PCa.

Feasibility of sentinel lymph node detection by near-infrared endoscopy in squamous cell carcinoma of the oral cavity: a pilot study

OBJECTIVE

Near-Infrared (NIR) fluorescence imaging is a novel technique for intraoperative sentinel lymph node (SLN) identification. It has demonstrated promising results in several surgical specialties. The study aims to evaluate the feasibility of identifying the SLN by indocyanine green (ICG) enhanced NIR endoscopy in squamous cell carcinoma of the oral cavity (OCSCC).

PATIENTS AND METHODS

Seven patients with (cT1-3 N0) OCSCC were included. We injected 1-1.25 ml of ICG (5 mg/ml) at four to five points around the primary. After the elevation of a platysma flap and posterior retraction of the sternocleidomastoid muscle, fluorescence images were taken via IMAGE1 STM NIR/ICG system to define the SLN(s). We sampled fluorescence marked SLN(s) stratified to lymph node levels, followed by level-specified elective neck dissection.

RESULTS

The detection of at least one unilateral or bilateral SLN (range 1-5) was possible in every case. The fluorescence signal occurred, on average, 5.0 ± 2.2 minutes after injection. A total of 22 SLN could be identified. Among 331 histologically examined lymph nodes we could detect one micrometastasis, which was correctly defined as SLN (1/22). There were no false-negative findings. No adverse reactions to ICG occurred.

CONCLUSIONS

Our first results are indicating the concept of SLN concerning OCSCC after the application of real-time NIR fluorescence endoscopy. However, this has to be verified by more extended studies.

Deep learning for diagnosis and survival prediction in soft tissue sarcoma

BACKGROUND

Clinical management of soft tissue sarcoma (STS) is particularly challenging. Here, we used digital pathology and deep learning (DL) for diagnosis and prognosis prediction of STS.

PATIENTS AND METHODS

Our retrospective, multicenter study included a total of 506 histopathological slides from 291 patients with STS. The Cancer Genome Atlas cohort (240 patients) served as training and validation set. A second, multicenter cohort (51 patients) served as an additional test set. The use of the DL model (DLM) as a clinical decision support system was evaluated by nine pathologists with different levels of expertise. For prognosis prediction, 139 slides from 85 patients with leiomyosarcoma (LMS) were used. Area under the receiver operating characteristic (AUROC) and accuracy served as main outcome measures.

RESULTS

The DLM achieved a mean AUROC of 0.97 (±0.01) and an accuracy of 79.9% (±6.1%) in diagnosing the five most common STS subtypes. The DLM significantly improved the accuracy of the pathologists from 46.3% (±15.5%) to 87.1% (±11.1%). Furthermore, they were significantly faster and more certain in their diagnosis. In LMS, the mean AUROC in predicting the disease-specific survival status was 0.91 (±0.1) and the accuracy was 88.9% (±9.9%). Cox regression showed the DLM's prediction to be a significant independent prognostic factor (P = 0.008, hazard ratio 5.5, 95% confidence interval 1.56-19.7) in these patients, outperforming other risk factors.

CONCLUSIONS

DL can be used to accurately diagnose frequent subtypes of STS from conventional histopathological slides. It might be used for prognosis prediction in LMS, the most prevalent STS subtype in our cohort. It can also help pathologists to make faster and more accurate diagnoses. This could substantially improve the clinical management of STS patients.

Differential regulation of Ca2+ influx by ORAI channels mediates enamel mineralization

Store-operated Ca²⁺ entry (SOCE) channels are highly selective Ca²⁺ channels activated by the endoplasmic reticulum (ER) sensors STIM1 and STIM2. Their direct interaction with the pore-forming plasma membrane ORAI proteins (ORAI1, ORAI2, and ORAI3) leads to sustained Ca²⁺ fluxes that are critical for many cellular functions. Mutations in the human ORAI1 gene result in immunodeficiency, anhidrotic ectodermal dysplasia, and enamel defects. In our investigation of the role of ORAI proteins in enamel, we identified enamel defects in a patient with an ORAI1 null mutation. Targeted deletion of the Orai1 gene in mice showed enamel defects and reduced SOCE in isolated enamel cells. However, Orai2^-/- mice showed normal enamel despite having increased SOCE in the enamel cells. Knockdown experiments in the enamel cell line LS8 suggested that ORAI2 and ORAI3 modulated ORAI1 function, with ORAI1 and ORAI2 being the main contributors to SOCE. ORAI1-deficient LS8 cells showed altered mitochondrial respiration with increased oxygen consumption rate and ATP, which was associated with altered redox status and enhanced ER Ca²⁺ uptake, likely due to S-glutathionylation of SERCA pumps. Our findings demonstrate an important role of ORAI1 in Ca²⁺ influx in enamel cells and establish a link between SOCE, mitochondrial function, and redox homeostasis.

Erratum: Ultrafast Doublon Dynamics in Photoexcited 1T-TaS_{2} [Phys. Rev. Lett. 120, 166401 (2018)]

This corrects the article DOI: 10.1103/PhysRevLett.120.166401.

Tissue resident and follicular Treg cell differentiation is regulated by CRAC channels

T regulatory (Treg) cells maintain immunological tolerance and organ homeostasis. Activated Treg cells differentiate into effector Treg subsets that acquire tissue-specific functions. Ca²⁺ influx via Ca²⁺ release-activated Ca²⁺ (CRAC) channels formed by STIM and ORAI proteins is required for the thymic development of Treg cells, but its function in mature Treg cells remains unclear. Here we show that deletion of Stim1 and Stim2 genes in mature Treg cells abolishes Ca²⁺ signaling and prevents their differentiation into follicular Treg and tissue-resident Treg cells. Transcriptional profiling of STIM1/STIM2-deficient Treg cells reveals that Ca²⁺ signaling regulates transcription factors and signaling pathways that control the identity and effector differentiation of Treg cells. In the absence of STIM1/STIM2 in Treg cells, mice develop a broad spectrum of autoantibodies and fatal multiorgan inflammation. Our findings establish a critical role of CRAC channels in controlling lineage identity and effector functions of Treg cells.

Regulatory T (Treg) cells are important for maintaining immune homeostasis. Here the authors show that STIM1 and STIM2, which activate the Ca²⁺ channel ORAI1, are essential for the differentiation of peripheral Treg cells into tissue-resident and follicular Treg cells and their ability to limit autoimmunity in mice.

CRAC channels in dental enamel cells

Enamel mineralization relies on Ca2+ availability provided by Ca2+ release activated Ca2+ (CRAC) channels. CRAC channels are modulated by the endoplasmic reticulum Ca2+ sensor STIM1 which gates the pore subunit of the channel known as ORAI1, found the in plasma membrane, to enable sustained Ca2+ influx. Mutations in the STIM1 and ORAI1 genes result in CRAC channelopathy, an ensemble of diseases including immunodeficiency, muscular hypotonia, ectodermal dysplasia with defects in sweat gland function and abnormal enamel mineralization similar to amelogenesis imperfecta (AI). In some reports, the chief medical complain has been the patient's dental health, highlighting the direct and important link between CRAC channels and enamel. The reported enamel defects are apparent in both the deciduous and in permanent teeth and often require extensive dental treatment to provide the patient with a functional dentition. Among the dental phenotypes observed in the patients, discoloration, increased wear, hypoplasias (thinning of enamel) and chipping has been reported. These findings are not universal in all patients. Here we review the mutations in STIM1 and ORAI1 causing AI-like phenotype, and evaluate the enamel defects in CRAC channel deficient mice. We also provide a brief overview of the role of CRAC channels in other mineralizing systems such as dentine and bone.

Evidence That Calcium Entry Into Calcium-Transporting Dental Enamel Cells Is Regulated by Cholecystokinin, Acetylcholine and ATP

Dental enamel is formed by specialized epithelial cells which handle large quantities of Ca²⁺ while producing the most highly mineralized tissue. However, the mechanisms used by enamel cells to handle bulk Ca²⁺ safely remain unclear. Our previous work contradicted the dogma that Ca²⁺ is ferried through the cytosol of Ca²⁺-transporting cells and instead suggested an organelle-based route across enamel cells. This new paradigm involves endoplasmic reticulum (ER)-associated Ca²⁺ stores and their concomitant refilling by store-operated Ca²⁺ entry (SOCE) mediated by Ca²⁺ release activated Ca²⁺ (CRAC) channels. Given that Ca²⁺ handling is maximal during the enamel-mineralization stage (maturation), we anticipated that SOCE would also be elevated then. Confirmation was obtained here using single-cell recordings of cytosolic Ca²⁺ concentration ([Ca²⁺]_cyt) in rat ameloblasts. A candidate SOCE agonist, cholecystokinin (CCK), was found to be upregulated during maturation, with Cck transcript abundance reaching 30% of that in brain. CCK-receptor transcripts were also detected and Ca²⁺ imaging showed that CCK stimulation increased [Ca²⁺]_cyt in a dose-responsive manner that was sensitive to CRAC-channel inhibitors. Similar effects were observed with two other SOCE activators, acetylcholine and ATP, whose receptors were also found in enamel cells. These results provide the first evidence of a potential regulatory system for SOCE in enamel cells and so strengthen the Ca²⁺ transcytosis paradigm for ER-based transport of bulk Ca²⁺. Our findings also implicate enamel cells as a new physiological target of CCK and raise the possibility of an auto/paracrine system for regulating Ca²⁺ transport.

The Anticoagulant Activity of 3.3’-(p-Alkylthio-Benzylidene)-Bis-4-Hydroxycoumarins and Their Oxidation Products

The anticoagulant activity of 3.3’-(benzylidene)-bis-4-hydroxycoumarin derivatives has been estimated by one step Quick’s method. The derivatives contained the following groups in the para position of benzylidene residue: NCS- (I), CH3-S- (II), CH3-SO-(III), CH3-S02- (IV), C2H5-S- (V), C2H5-SO- (VI), C2H5-S02- (VII). All these compounds were much more active than 3.3’-(benzylidene)-bis-4-hydroxycoumarin itself.

Compounds possessing the ethyl chain at the sulphur atom (V, VI, VII) were more active than methyl homologues (II, III, IV). Comparison of the activity of the series of thio-, sulphoxy-, and sulphonyl-derivatives showed that among methyl- and ethyl-derivatives those with the sulphoxy grouping (III, VI) displayed the greatest anticoagulant activity. The action of sulphonyl (IV, VII) and thio-derivatives (II, V) was weaker and shortest. The derivative with the NCS-group (I) possessed a relatively the lowest activity among the investigated compounds. 3.3’-(p-Ethylsulphoxybenzyl-idene)-bis-4-hydroxycoumarin (VI), with distinct biological activity reached about ½ of dicoumarol activity.

Altered Ca2+ signaling in enamelopathies

Biomineralization requires the controlled movement of ions across cell barriers to reach the sites of crystal growth. Mineral precipitation occurs in aqueous phases as fluids become supersaturated with specific ionic compositions. In the biological world, biomineralization is dominated by the presence of calcium (Ca²⁺) in crystal lattices. Ca²⁺ channels are intrinsic modulators of this process, facilitating the availability of Ca²⁺ within cells in a tightly regulated manner in time and space. Unequivocally, the most mineralized tissue produced by vertebrates, past and present, is dental enamel. With some of the longest carbonated hydroxyapatite (Hap) crystals known, dental enamel formation is fully coordinated by specialized epithelial cells of ectodermal origin known as ameloblasts. These cells form enamel in two main developmental stages: a) secretory; and b) maturation. The secretory stage is marked by volumetric growth of the tissue with limited mineralization, and the opposite is found in the maturation stage, as enamel crystals expand in width concomitant with increased ion transport. Disruptions in the formation and/or mineralization stages result, in most cases, in permanent alterations in the crystal assembly. This introduces weaknesses in the material properties affecting enamel's hardness and durability, thus limiting its efficacy as a biting, chewing tool and increasing the possibility of pathology. Here, we briefly review enamel development and discuss key properties of ameloblasts and their Ca²⁺-handling machinery, and how alterations in this toolkit result in enamelopathies.

Role of Dysregulated Cytokine Signaling and Bacterial Triggers in the Pathogenesis of Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma is a heterogeneous group of lymphomas characterized by the accumulation of malignant T cells in the skin. The molecular and cellular etiology of this malignancy remains enigmatic, and what role antigenic stimulation plays in the initiation and/or progression of the disease remains to be elucidated. Deep sequencing of the tumor genome showed a highly heterogeneous landscape of genetic perturbations, and transcriptome analysis of transformed T cells further highlighted the heterogeneity of this disease. Nonetheless, using data harvested from high-throughput transcriptional profiling allowed us to develop a reliable signature of this malignancy. Focusing on a key cytokine signaling pathway previously implicated in cutaneous T-cell lymphoma pathogenesis, JAK/STAT signaling, we used conditional gene targeting to develop a fully penetrant small animal model of this disease that recapitulates many key features of mycosis fungoides, a common variant of cutaneous T-cell lymphoma. Using this mouse model, we show that T-cell receptor engagement is critical for malignant transformation of the T lymphocytes and that progression of the disease is dependent on microbiota.

Ultrafast Doublon Dynamics in Photoexcited 1T-TaS_{2}

Strongly correlated materials exhibit intriguing properties caused by intertwined microscopic interactions that are hard to disentangle in equilibrium. Employing nonequilibrium time-resolved photoemission spectroscopy on the quasi-two-dimensional transition-metal dichalcogenide 1T-TaS_{2}, we identify a spectroscopic signature of doubly occupied sites (doublons) that reflects fundamental Mott physics. Doublon-hole recombination is estimated to occur on timescales of electronic hopping ℏ/J≈14  fs. Despite strong electron-phonon coupling, the dynamics can be explained by purely electronic effects captured by the single-band Hubbard model under the assumption of weak hole doping, in agreement with our static sample characterization. This sensitive interplay of static doping and vicinity to the metal-insulator transition suggests a way to modify doublon relaxation on the few-femtosecond timescale.

Prognostic Value of Molecular Breast Cancer Subtypes based on Her2, ESR1, PGR and Ki67 mRNA-Expression in Muscle Invasive Bladder Cancer

INTRODUCTION: Gene expression analyses have identified similarities between bladder and breast cancer, where clinical risk stratification is based on Her2, ESR1, PGR and Ki67 expression. The aim of the study was to assess the respective marker gene expression in patients treated with radical cystectomy for muscle-invasive bladder cancer (MIBC) and to evaluate the applicability of breast cancer subtypes for MIBC risk stratification. MATERIALS & METHODS: 102 patients treated with radical cystectomy for MIBC were assessed. Using routine FFPE tissue and an IVD validated kit, mRNA expression was measured by single step RT-qPCR. Partition test were employed to define cut-off values for high or low marker gene expression. Association of expression with outcome was assessed using Kaplan-Meier analysis and multivariate cox regression analysis. Finally, we performed validation of our results in the MD-Anderson cohort (n = 57). RESULTS: Cancer specific survival (CSS) was impaired in patients with high gene expression of Her2 (P = 0.0009) and ESR1 (P = 0.04). In the multivariate regression model Her2 expression remained significant for the prediction of CSS (HR = 2.11, CI 1.11-4.21, P = 0.024). Furthermore, molecular stratification by breast cancer subgroups was significant (P = 0.023) for CSS prediction. Especially the differentiation between Her2-positive and Luminal A (HR = 4.41, CI 1.53-18.71, P = 0.004) and Luminal B (HR = 1.96, CI 0.99-4.08, P = 0.053) respectively was an independent prognostic parameter for CSS. External validation resulted in comparable risk stratification with differences in fractional subgroups distribution. CONCLUSION: Gene expression of Her2, ESR1, PGR, Ki67 and corresponding breast cancer subtypes allow a risk-stratification in MIBC, whereby Her2 overexpressing tumors reveal a particularly poor prognosis.

Store-Operated Ca2+ Entry Controls Clonal Expansion of T Cells through Metabolic Reprogramming

Store-operated Ca2+ entry (SOCE) is the main Ca2+ influx pathway in lymphocytes and is essential for T cell function and adaptive immunity. SOCE is mediated by Ca2+ release-activated Ca2+ (CRAC) channels that are activated by stromal interaction molecule (STIM) 1 and STIM2. SOCE regulates many Ca2+-dependent signaling molecules, including calcineurin, and inhibition of SOCE or calcineurin impairs antigen-dependent T cell proliferation. We here report that SOCE and calcineurin regulate cell cycle entry of quiescent T cells by controlling glycolysis and oxidative phosphorylation. SOCE directs the metabolic reprogramming of naive T cells by regulating the expression of glucose transporters, glycolytic enzymes, and metabolic regulators through the activation of nuclear factor of activated T cells (NFAT) and the PI3K-AKT kinase-mTOR nutrient-sensing pathway. We propose that SOCE controls a critical "metabolic checkpoint" at which T cells assess adequate nutrient supply to support clonal expansion and adaptive immune responses.

Ca2+ transport and signalling in enamel cells

Dental enamel is one of the most remarkable examples of matrix-mediated biomineralization. Enamel crystals form de novo in a rich extracellular environment in a stage-dependent manner producing complex microstructural patterns that are visually stunning. This process is orchestrated by specialized epithelial cells known as ameloblasts which themselves undergo striking morphological changes, switching function from a secretory role to a cell primarily engaged in ionic transport. Ameloblasts are supported by a host of cell types which combined represent the enamel organ. Fully mineralized enamel is the hardest tissue found in vertebrates owing its properties partly to the unique mixture of ionic species represented and their highly organized assembly in the crystal lattice. Among the main elements found in enamel, Ca2+ is the most abundant ion, yet how ameloblasts modulate Ca2+ dynamics remains poorly known. This review describes previously proposed models for passive and active Ca2+ transport, the intracellular Ca2+ buffering systems expressed in ameloblasts and provides an up-dated view of current models concerning Ca2+ influx and extrusion mechanisms, where most of the recent advances have been made. We also advance a new model for Ca2+ transport by the enamel organ.