Structures of a sperm-specific solute carrier gated by voltage and cAMP.

The newly characterized sperm-specific Na+/H+ exchanger stands out by its unique tripartite domain composition1,2. It unites a classical solute carrier unit with regulatory domains usually found in ion channels, namely, a voltage-sensing domain and a cyclic-nucleotide binding domain1,3, which makes it a mechanistic chimera and a secondary-active transporter activated strictly by membrane voltage. Our structures of the sea urchin SpSLC9C1 in the absence and presence of ligands reveal the overall domain arrangement and new structural coupling elements. They allow us to propose a gating model, where movements in the voltage sensor indirectly cause the release of the exchanging unit from a locked state through long-distance allosteric effects transmitted by the newly characterized coupling helices. We further propose that modulation by its ligand cyclic AMP occurs by means of disruption of the cytosolic dimer interface, which lowers the energy barrier for S4 movements in the voltage-sensing domain. As SLC9C1 members have been shown to be essential for male fertility, including in mammals2,4,5, our structure represents a potential new platform for the development of new on-demand contraceptives.

Antiviral signalling by a cyclic nucleotide activated CRISPR protease.

CRISPR defence systems such as the well-known DNA-targeting Cas9 and the RNA-targeting type III systems are widespread in prokaryotes1,2. The latter orchestrates a complex antiviral response that is initiated through the synthesis of cyclic oligoadenylates after recognition of foreign RNA3-5. Among the large set of proteins that are linked to type III systems and predicted to bind cyclic oligoadenylates6,7, a CRISPR-associated Lon protease (CalpL) stood out to us. CalpL contains a sensor domain of the SAVED family7 fused to a Lon protease effector domain. However, the mode of action of this effector is unknown. Here we report the structure and function of CalpL and show that this soluble protein forms a stable tripartite complex with two other proteins, CalpT and CalpS, that are encoded on the same operon. After activation by cyclic tetra-adenylate (cA4), CalpL oligomerizes and specifically cleaves the MazF homologue CalpT, which releases the extracytoplasmic function σ factor CalpS from the complex. Our data provide a direct connection between CRISPR-based detection of foreign nucleic acids and transcriptional regulation. Furthermore, the presence of a SAVED domain that binds cyclic tetra-adenylate in a CRISPR effector reveals a link to the cyclic-oligonucleotide-based antiphage signalling system.

CD20-bispecific antibodies improve response to CD19-CAR T cells in lymphoma in vitro and CLL in vivo models.

ABSTRACT: Relapse after anti-CD19 chimeric antigen receptor (CD19-CAR) occurs in a substantial proportion of patients with lymphoid malignancies. We assessed the potential benefits of co-administering CD20-targeting bispecific antibodies (CD20-BsAbs) with CD19-CAR T cells with the aim of enhancing immunotherapeutic efficacy. Addition of CD20-BsAbs to cocultures of CD19-CARs and primary samples of B-cell malignancies, comprising malignant B cells and endogenous T cells, significantly improved killing of malignant cells and enhanced the expansion of both endogenous T cells and CD19-CAR T cells. In an immunocompetent mouse model of chronic lymphocytic leukemia, relapse after initial treatment response frequently occurred after CD19-CAR T-cell monotherapy. Additional treatment with CD20-BsAbs significantly enhanced the treatment response and led to improved eradication of malignant cells. Higher efficacy was accompanied by improved T-cell expansion with CD20-BsAb administration and led to longer survival with 80% of the mice being cured with no detectable malignant cell population within 8 weeks of therapy initiation. Collectively, our in vitro and in vivo data demonstrate enhanced therapeutic efficacy of CD19-CAR T cells when combined with CD20-BsAbs in B-cell malignancies. Activation and proliferation of both infused CAR T cells and endogenous T cells may contribute to improved disease control.

T-bet suppresses proliferation of malignant B cells in chronic lymphocytic leukemia.

ABSTRACT: The T-box transcription factor T-bet is known as a master regulator of the T-cell response but its role in malignant B cells has not been sufficiently explored. Here, we conducted single-cell resolved multi-omics analyses of malignant B cells from patients with chronic lymphocytic leukemia (CLL) and studied a CLL mouse model with a genetic knockout of Tbx21. We found that T-bet acts as a tumor suppressor in malignant B cells by decreasing their proliferation rate. NF-κB activity, induced by inflammatory signals provided by the microenvironment, triggered T-bet expression, which affected promoter-proximal and distal chromatin coaccessibility and controlled a specific gene signature by mainly suppressing transcription. Gene set enrichment analysis identified a positive regulation of interferon signaling and negative control of proliferation by T-bet. In line, we showed that T-bet represses cell cycling and is associated with longer overall survival of patients with CLL. Our study uncovered a novel tumor suppressive role of T-bet in malignant B cells via its regulation of inflammatory processes and cell cycling, which has implications for the stratification and therapy of patients with CLL. Linking T-bet activity to inflammation explains the good prognostic role of genetic alterations in the inflammatory signaling pathways in CLL.

Characterization of Vascular Niche in Systemic Sclerosis by Spatial Proteomics.

BACKGROUND: Systemic sclerosis (SSc) is a connective tissue disease that can serve as a model to study vascular changes in response to inflammation, autoimmunity, and fibrotic remodeling. Although microvascular changes are the earliest histopathologic manifestation of SSc, the vascular pathophysiology remains poorly understood. METHODS: We applied spatial proteomic approaches to deconvolute the heterogeneity of vascular cells at the single-cell level in situ and characterize cellular alterations of the vascular niches of patients with SSc. Skin biopsies of patients with SSc and control individuals were analyzed by imaging mass cytometry, yielding a total of 90 755 cells including 2987 endothelial cells and 4096 immune cells. RESULTS: We identified 7 different subpopulations of blood vascular endothelial cells (VECs), 2 subpopulations of lymphatic endothelial cells, and 3 subpopulations of pericytes. A novel population of CD34+;αSMA+ (α-smooth muscle actin);CD31+ VECs was more common in SSc, whereas endothelial precursor cells were decreased. Co-detection by indexing and tyramide signal amplification confirmed these findings. The microenvironment of CD34+;αSMA+;CD31+ VECs was enriched for immune cells and myofibroblasts, and CD34+;αSMA+;CD31+ VECs expressed markers of endothelial-to-mesenchymal transition. The density of CD34+;αSMA+;CD31+ VECs was associated with clinical progression of fibrosis in SSc. CONCLUSIONS: Using spatial proteomics, we unraveled the heterogeneity of vascular cells in control individuals and patients with SSc. We identified CD34+;αSMA+;CD31+ VECs as a novel endothelial cell population that is increased in patients with SSc, expresses markers for endothelial-to-mesenchymal transition, and is located in close proximity to immune cells and myofibroblasts. CD34+;αSMA+;CD31+ VEC counts were associated with clinical outcomes of progressive fibrotic remodeling, thus providing a novel cellular correlate for the crosstalk of vasculopathy and fibrosis.

Current Management of T1 Colon Cancer in Denmark: A Nationwide Cohort Study.

OBJECTIVE: To describe the management of T1 colon cancer in a retrospective study of a national cancer registry. BACKGROUND: There is increasing interest in the potential of local excision (LE) as an organ-preserving treatment for early colon cancer. However, accurate identification of patients who may have lymph node metastases (LNM) and require further surgery is a major challenge. METHODS: Patients diagnosed with T1 colon cancer in Denmark from 2016 to 2020 were included and divided according to treatment: polypectomy (referred to as LE), upfront colectomy and completion colectomy. Primary outcome was the proportion of patients diagnosed by LE. Secondary outcomes included the rate of LNM, the association of histopathological risk factors with LNM, and overall survival. RESULTS: 1,749 patients were included, and 1,022 patients (58.4%) underwent initial LE. The rate of R1 margins after initial LE was 31.0%. Colectomy was performed in 1,160 patients (upfront in 727, completion in 433), of whom 58.3% had pT1 cancer. The rate of LNM was 11.5%. Rates of LNM were similar in patients undergoing upfront or completion colectomy (10.2% vs 12.4%, P=0.392), and in patients with any single histopathological risk factor compared to those with none (8.9% vs 10.6%, P=0.565). Although overall survival was significantly shorter in patients undergoing LE alone, no association between survival and treatment strategy was found on multivariable analysis. CONCLUSIONS: LE is the most common mode of diagnosis in patients with T1 colon cancer and does not negatively impact survival and postoperative outcomes. Current strategies to stratify patients to completion surgery appear insufficient, and more robust predictors are needed.

Venetoclax synergizes with gilteritinib in FLT3 wild-type high-risk acute myeloid leukemia by suppressing MCL-1.

BCL-2 inhibition has been shown to be effective in acute myeloid leukemia (AML) in combination with hypomethylating agents or low-dose cytarabine. However, resistance and relapse represent major clinical challenges. Therefore, there is an unmet need to overcome resistance to current venetoclax-based strategies. We performed high-throughput drug screening to identify effective combination partners for venetoclax in AML. Overall, 64 antileukemic drugs were screened in 31 primary high-risk AML samples with or without venetoclax. Gilteritinib exhibited the highest synergy with venetoclax in FLT3 wild-type AML. The combination of gilteritinib and venetoclax increased apoptosis, reduced viability, and was active in venetoclax-azacitidine-resistant cell lines and primary patient samples. Proteomics revealed increased FLT3 wild-type signaling in specimens with low in vitro response to the currently used venetoclax-azacitidine combination. Mechanistically, venetoclax with gilteritinib decreased phosphorylation of ERK and GSK3B via combined AXL and FLT3 inhibition with subsequent suppression of the antiapoptotic protein MCL-1. MCL-1 downregulation was associated with increased MCL-1 phosphorylation of serine 159, decreased phosphorylation of threonine 161, and proteasomal degradation. Gilteritinib and venetoclax were active in an FLT3 wild-type AML patient-derived xenograft model with TP53 mutation and reduced leukemic burden in 4 patients with FLT3 wild-type AML receiving venetoclax-gilteritinib off label after developing refractory disease under venetoclax-azacitidine. In summary, our results suggest that combined inhibition of FLT3/AXL potentiates venetoclax response in FLT3 wild-type AML by inducing MCL-1 degradation. Therefore, the venetoclax-gilteritinib combination merits testing as a potentially active regimen in patients with high-risk FLT3 wild-type AML.

Current treatment of pT1 rectal cancers in Denmark: A retrospective national cohort study.

AIM: Organ preservation strategies for patients with rectal cancer are increasingly common. In appropriately selected patients, local excision (LE) of pT1 cancers can reduce morbidity without compromising cancer-related outcomes. However, determining the need for completion surgery after LE can be challenging, and it is unknown if prior LE compromises subsequent total mesorectal excision (TME). The aim of this study is to describe the current management of patients with pT1 rectal cancers. METHOD: This is a retrospective national cohort study of the Danish Colorectal Cancer Group database, including patients with newly diagnosed pT1 cancers between 2016 and 2020. Patients were stratified according to treatment into LE alone, completion TME after LE or upfront TME. The treatment and outcomes of these groups were compared. RESULTS: A total of 1056 patients were included. Initial LE was performed in 715 patients (67.7%), of whom 194 underwent completion TME (27.1%). The remaining 341 patients underwent upfront TME (32.3%). Patients undergoing LE alone were more likely to be male with low rectal cancers and greater comorbidity. No differences in specimen quality or perioperative outcomes were noted between patients undergoing completion or upfront TME. Eighty-five patients (15.9%) had lymph node metastases (LNM). Pathological risk factors poorly discriminated between patients with and without LNM, with similar rates seen in patients with zero (14.1%), one (12.0%) or two (14.4%) risk factors. CONCLUSION: LE is a key component of the treatment of pT1 rectal cancer and does not appear to affect the outcomes of completion TME. Patient selection for completion TME remains a major challenge, with current stratification methods appearing to be inadequate.

Associations between health-related quality of life and subsequent need for specialized palliative care and hospital utilization in patients with gastrointestinal cancer-a prospective single-center cohort study.

BACKGROUND: We lack knowledge of which factors are associated with the risk of developing complex palliative care needs. The aim of this study was to investigate the associations between patient-reported health-related quality of life and subsequent referral to specialized palliative care (SPC) and hospital utilization. METHODS: This was a prospective single-center cohort study. Data on patient-reported outcomes were collected through the European Organization of Research and Treatment of Cancer Questionnaire-Core-15-Palliative Care (EORTC QLQ-C15-PAL) at the time of diagnosis. Covariates and hospital utilization outcomes were collected from medical records. Adjusted logistic and Poisson regression were applied in the analyses. Participants were newly diagnosed with incurable gastrointestinal cancer and affiliated with a palliative care case management intervention established in a gastroenterology department. RESULTS: Out of 397 patients with incurable gastrointestinal cancer, 170 were included in the study. Patients newly diagnosed with incurable gastrointestinal cancer experienced a substantial burden of symptoms. Pain was significantly associated with subsequent referral to SPC (OR 1.015; 95% CI 1.001-1.029). Patients with lower education levels (OR 0.210; 95% CI 0.056-0.778) and a Charlson Comorbidity Index score of 2 or more (OR 0.173; 95% CI 0.041-0.733) were less likely to be referred to SPC. Pain (IRR 1.011; 95% CI 1.005-1.018), constipation (IRR 1.009; 95% CI 1.004-1.015), and impaired overall quality of life (IRR 0.991; 95% CI 0.983-0.999) were significantly associated with increased risk of hospital admissions. CONCLUSION: The study indicates a need for interventions in hospital departments to identify and manage the substantial symptom burden experienced by patients, provide palliative care, and ensure timely referral to SPC.

Palliative care case management in a surgical department for patients with gastrointestinal cancer-a register-based cohort study.

BACKGROUND: The effectiveness of generalist palliative care interventions in hospitals is unknown. AIM: This study aimed to explore the impact of a palliative care case management intervention for patients with gastrointestinal cancer (PalMaGiC) on hospital admissions, healthcare use, and place of death. DESIGN: This was a register-based cohort study analyzing data from the Danish Register on Causes of Death, the Danish National Patient Register, and the Danish Palliative Database. SETTING/PARTICIPANTS: Deceased patients with gastrointestinal cancer from 2010 to 2020 exposed to PalMaGiC were compared over three periods of time to patients receiving standard care. RESULTS: A total of 43,969 patients with gastrointestinal cancers were included in the study, of whom 1518 were exposed to PalMaGiC. In the last 30 days of life, exposed patients were significantly more likely to be hospitalized (OR of 1.62 (95% CI 1.26-2.01)), spend more days at the hospital, estimate of 1.21 (95% CI 1.02-1.44), and have a higher number of hospital admissions (RR of 1.13 (95% CI 1.01-1.27)), and were more likely to die at the hospital (OR of 1.94 (95% CI 1.55-2.44)) with an increasing trend over time. No differences were found for hospital healthcare use. CONCLUSION: Patients exposed to the PalMaGiC intervention had a greater likelihood of hospitalizations and death at the hospital compared to unexposed patients, despite the opposite intention. Sensitivity analyses show that regional differences may hold some of the explanation for this. Future development of generalist palliative care in hospitals should focus on integrating a home-based approach, community care, and PC physician involvement.