Peter Möller

Background: Cystic echinococcosis (CE) and alveolar echinococcosis (AE) are zoonotic diseases caused by the larval stages of Echinococcus granulosus and E. multilocularis . Prior studies have identified small particles from the outer layer of parasitic lesions termed spegs (from E. granulosus ) and spems (from E. multilocularis ), which appear to interact with the human immune system, leading to lymph node enlargement. Methods: We analyzed lymph nodes from CE ( n = 3) and AE ( n = 3) patients by immunohistochemical staining for spegs/spems and CD57. Automated image analysis revealed a significantly increased number of CD57-positive cells in Echinococcus particle-positive germinal centers compared with speg-/spem-negative germinal centers. Double immunofluorescence staining was used to characterize CD57-positive cells with markers for CD2, CD3, CD4, CD8, PD-1, Granzyme B, Perforin, and T-cell intracellular antigen 1 (TIA1). Additionally, IgG4 and IgE immunostaining was performed on liver lesions and lymph nodes containing spegs and spems and compared with unaffected controls. Results: Spegs and spems were found to accumulate in the germinal centers of the lymph nodes. Affected germinal centers showed a higher number of CD57-positive cells, which coexpressed CD2, CD3, CD4, and PD-1 but lacked cytotoxic markers (CD8, Granzyme B, Perforin, TIA1), identifying them as follicular helper T cells (Tfh). Furthermore, the speg- and spem-affected liver and lymph node sections exhibited significantly increased numbers of IgG4-, IgE-, and CD57-positive cells. Conclusions: Spegs and spems are associated with changes in the host immune response, characterized by an increased accumulation of Tfh in germinal centers. This finding is accompanied by the presence of IgE and IgG4 plasma cells in the lymph node and the perilesional area, suggesting parasite-associated immunomodulatory processes in echinococcosis. Graphical

Although oxidants are known to be deleterious for cellular homeostasis by oxidizing macromolecules like DNA or proteins, they are also involved in signaling processes essential for cellular proliferation and survival. Here, we investigated the role of superoxide anion (O₂⁻) and hydrogen peroxide (H₂O₂) homeostasis for the proliferation and survival of classical Hodgkin’s lymphoma (cHL) cell lines. Inhibition of NADPH oxidases (NOX) using apocynin (Apo) and diphenylene iodonium (DPI), or treatment with the antioxidant butylated hydroxyanisole (BHA), significantly reduced proliferation and induced apoptosis in HL cell lines. These effects correlated with transcriptomic alterations involving redox regulation, immune signaling, and cell cycle control. Interestingly, treatment with DPI or antioxidants attenuated constitutive Signal Transducer and Activator of Transcription (STAT) activity, as seen by decreased phospho-STAT6 levels and reduced STAT6 DNA binding. This suggests a sensitivity of the Janus kinase (JAK)/STAT pathway in cHL cell lines to O₂⁻ and H₂O₂ depletion. Functional assays confirmed this by demonstrating partial restoration of proliferation or apoptosis in L428 cells that expressed constitutively active STAT6 or were transfected with small interfering RNAs (siRNAs) that targeted STAT regulators. These findings highlight that oxidants, particularly H₂O₂, act as both general oxidative stressors and essential modulators of oncogenic signaling pathways. Specifically, maintenance of oxidant homeostasis is critical for sustaining JAK/STAT-mediated growth and survival programs in cHL cells. Targeting redox homeostasis might offer a promising therapeutic strategy to impair JAK/STAT-driven proliferation and survival in cHL.

Chordomas are rare malignant tumors of the bone, originating from remnants of notochordal cells. The transcription factor brachyury, encoded by TBXT, serves as a critical diagnostic marker and is essential for tumor growth. While brachyury’s role in regulating the cytoskeleton during embryogenesis and tumorigenesis is well understood, the reverse—whether cytoskeletal alterations can influence brachyury levels—remains unclear. Despite advances in understanding chordoma biology, there are currently no approved targeted therapies, underscoring the need for novel therapeutic approaches. Three chordoma cell lines were treated with cytoskeletal inhibitors, including the actin-targeting compounds Cucurbitacin B (CuB) and Latrunculin B (LatB). Morphological changes, TBXT expression, and cell viability were analyzed. The effects of CuB were examined over time and across concentrations, with cell viability assessed via apoptosis and cytotoxicity assays. Microarray gene expression profiling of ten chordoma cell lines was performed to explore CuB-mediated transcriptional changes. Rescue experiments using a TBXT open reading frame vector and co-treatments with autophagy and proteasome inhibitors were conducted to elucidate the mechanisms of brachyury depletion. Both CuB and LatB induced significant morphological changes, but only CuB caused near-complete depletion of brachyury. This effect was time- and concentration-dependent, correlating with reduced cell viability driven primarily by apoptosis. Microarray analysis revealed that CuB treatment upregulated protein refolding pathways and downregulated protein glycosylation. Notably, TBXT transcription was only slightly suppressed, indicating that brachyury depletion was largely post-transcriptional. Rescue experiments and co-treatments implicated dysregulated protein refolding and endoplasmic reticulum (ER) stress as key mechanisms underlying CuB-mediated brachyury loss. This study demonstrates that actin cytoskeleton disruption by CuB depletes brachyury in chordoma cells, primarily through dysregulated protein refolding and ER stress rather than transcriptional repression. These findings suggest that targeting actin cytoskeleton dynamics or protein unfolding pathways may provide novel therapeutic approaches for chordoma treatment.

Objectives: Primary nodal marginal B-cell lymphoma (NMZL) is rare and histologically very variable. Its large-cell presentation is difficult to distinguish from nodal diffuse large B-cell lymphoma (nDLBCL) due to the absence of specific markers for nodal marginal zone lymphomas in general. Methods: Using a comprehensive cohort of NMZLs and a control cohort of nDLBCLs, we conducted a methylome analysis on subgroups of both. Results: The methylomes were strikingly different between the cohorts but unexpectedly homogeneous within the NMZL cohort. This allowed us to describe the morphologic spectrum of NMZL in all its value ranges. The considerable overlap in growth pattern and cytology of NMZL with nDLBCL was explored morphometrically, leading to an operational tool for separating both by a simple measurement of cell size and nuclear size. This was integrated in a hierarchical approach, including a scoring system for the parameter growth pattern, follicular colonization, follicular dendritic network, IgD expression, and Ki-67 rate, and led to a proposal for a classifier that we present here. Conclusions: This methylome-based study extends the morphological spectrum of NMZL towards large cell morphology and offers a conventional way to distinguish it from nDLBCL.

Chordomas are very rare malignant neoplasms of the bone occurring almost exclusively along the spine. As the tumours are thought to arise from notochordal remnants, the vast majority of chordomas express the TBXT gene, resulting in detectable nuclear amounts of its gene product brachyury. This T-Box transcription factor is commonly recognised as being essential in chordoma cells, and limiting TBXT expression is thought to be the key factor in controlling this tumour. Although the tumour is rare, distinct molecular differences and vulnerabilities have been described with regard to its location and the progression status of the disease, rendering it mandatory for novel cell lines to reflect all relevant chordoma subtypes. Here, we describe a novel chordoma cell line arising from the pleural effusion of a disseminated, poorly differentiated chordoma. This cell line, U-CH22, represents a highly aggressive terminal chordoma and, therefore, fills a relevant gap within the panel of available cell culture models for this orphan disease. CDK7 and CDK9 inhibition was lately identified as being effective in reducing viability in four chordoma cell lines, most likely due to a reduction in brachyury levels. In this study, we determined the capability of the CDK7 inhibitor THZ1 and the CDK1/2/5/9 inhibitor dinaciclib to reduce TBXT expression at mRNA and protein levels in a broad range of nine cell lines that are models of primary, recurrent, and metastasised chordoma of the clivus and the sacrum.