Thrombocytopenia is a feared complication of preeclampsia (PE) that can additionally complicate the disease course and that carries a poor prognosis. The disease mechanisms of PE on a platelet level ...are poorly understood and only few platelet-based markers have been investigated. In sepsis, platelet mitochondrial membrane depolarization, a sensitive and early indicator of mitochondrial dysfunction and platelet cell death, correlates with disease severity and outcome as shown in previous studies. The aim of this study was to investigate platelet mitochondrial membrane potential (Mmp-Index) by flow-cytometry in patients with preeclampsia compared to controls and to assess its value in correlation with disease severity of PE and during follow-up after delivery.
In this prospective translational case-control study, platelet Mmp-Index was measured in PE (n = 16) by flow cytometry in living platelets in simultaneous comparison to healthy pregnant (n = 32) and non-pregnant controls (n = 16) and was individually reassessed after delivery to investigate recovery of platelet mitochondrial function. Subgroup analysis of patients with severe and non-severe PE was performed. Six patients with isolated gestational hypertension were also included for comparative analysis.
Platelet Mmp-Index in patients with symptomatic preeclampsia (Mmp-Index non-severe PE 0.72 (0.591; 0.861; p = 0.002) was significantly reduced compared to healthy pregnant controls (Mmp-Index 0.97 0.795; 1.117) and even more pronounced in patients with severe PE (n = 6) (Mmp-Index severe PE 0.542 0.361; 0.623; p = 0.03). In the severe PE group, complementary measurements of platelet Annexin V- and CD62 (P-Selectin) surface expression showed apoptosis of platelet populations in the majority of patients. Platelet Mmp normalized after delivery within few days. Patients with isolated gestational hypertension showed normal Mmp-Index values.
This study shows for the first time that platelet Mmp-Index is a quantifiable, easy-to-measure intracellular marker of platelet mitochondrial function in vital cells that reflects disease severity of preeclampsia. For future investigations, platelet Mmp may serve as a prognostic marker that may aid clinical risk stratification and adds novel information on potential mechanisms for thrombocytopenia in preeclampsia.
Response to immune checkpoint blockade (ICB) in ovarian cancer remains disappointing. Several studies have identified the chemokine CXCL9 as a robust prognosticator of improved survival in ovarian ...cancer and a characteristic of the immunoreactive subtype, which predicts ICB response. However, the function of CXCL9 in ovarian cancer has been poorly studied.
Impact of Cxcl9 overexpression in the murine ID8-Trp53
and ID8-Trp53
Brca2
ovarian cancer models on survival, cellular immune composition, PD-L1 expression and anti-PD-L1 therapy. CXCL9 expression analysis in ovarian cancer subtypes and correlation to reported ICB response.
CXCL9 overexpression resulted in T-cell accumulation, delayed ascites formation and improved survival, which was dependent on adaptive immune function. In the ICB-resistant mouse model, the chemokine was sufficient to enable a successful anti-PD-L1 therapy. In contrast, these effects were abrogated in Brca2-deficient tumours, most likely due to an already high intrinsic chemokine expression. Finally, in ovarian cancer patients, the clear-cell subtype, known to respond best to ICB, displayed a significantly higher proportion of CXCL9
tumours than the other subtypes.
CXCL9 is a driver of successful ICB in preclinical ovarian cancer. Besides being a feasible predictive biomarker, CXCL9-inducing agents thus represent attractive combination partners to improve ICB in this cancer entity.
CX3CL1 is a multifunctional chemokine that is involved in numerous biological processes, such as immune cell attraction and enhanced tumor immune cell interaction, but also in enhancing tumor cell ...proliferation and metastasis. The multifarious activity is partially determined by two CX3CL1 isoforms, a membrane-bound and a soluble version generated by proteolytic cleavage through proteases. Here, we investigated the impact of CX3CL1 overexpression in MDA-MB-453 and SK-BR-3 breast cancer cells. Moreover, we evaluated the therapeutic capacity of Matrix-Metalloproteinases-inhibitors TMI-1 and GI254023X in combination with the anti-HER2 antibody trastuzumab in vitro and in vivo. TMI-1 and GI254023X caused a reduced shedding of CX3CL1 and of HER2 in vitro but without effects on tumor cell proliferation or viability. In addition, trastuzumab treatment did not retard MDA-MB-453 cell expansion in vitro unless CX3CL1 was overexpressed upon transfection (MDA-MB-453CX3CL1). In humanized tumor mice, which show a coexistence of human tumor and human immune system, CX3CL1 overexpression resulted in a slightly enhanced tumor growth. However, trastuzumab treatment attenuated tumor growth of both MDA-MB-453CX3CL1 and empty vector transfected MDA-MB-453 transplanted mice but showed enhanced efficiency especially in preventing lung metastases in CX3CL1 overexpressing cancer cells. However, TMI-1 did not further enhance the trastuzumab treatment efficacy.
Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with poor patient prognosis and limited therapeutic options. A lack of prognostic biomarkers and therapeutic targets fuels ...the need for new approaches to tackle this severe disease. Extracellular matrix degradation, release, and modulation of the activity of growth factors/cytokines/chemokines, and the initiation of signaling pathways by extracellular proteolytic networks, have been identified as major processes in the carcinogenesis of breast cancer. Members of the kallikrein-related peptidase (KLK) family contribute to these tumor-relevant processes, and are associated with breast cancer progression and metastasis. In this study, the clinical relevance of mRNA expression of two members of this family, KLK10 and KLK11, has been evaluated in TNBC. For this, their expression levels were quantified in tumor tissue of a large, well-characterized patient cohort (n = 123) via qPCR. Although, in general, the overall expression of both factors are lower in tumor tissue of breast cancer patients (encompassing all subtypes) compared to normal tissue of healthy donors, in the TNBC subtype, expression is even increased. In our cohort, a significant, positive correlation between the expression levels of both KLKs was detected, indicating a coordinate expression mode of these proteases. Elevated KLK10 and KLK11 mRNA levels were associated with poor patient prognosis. Moreover, both factors were found to be independent of other established clinical factors such as age, lymph node status, or residual tumor mass, as determined by multivariable Cox regression analysis. Thus, both proteases, KLK10 and KLK11, may represent unfavorable prognostic factors for TNBC patients and, furthermore, appear as promising potential targets for therapy in TNBC.
The tetraspanin and tumor suppressor KAI1 is downregulated or lost in many cancers which correlates with poor prognosis. KAI1 acts via physical/functional crosstalk with other membrane receptors. ...Also, a splice variant of KAI1 (KAI1-SP) has been identified indicative of poor prognosis. We here characterized differential effects of the two KAI1 variants on tumor biological events involving integrin (αvß3) and/or epidermal growth factor receptor (EGF-R). In MDA-MB-231 and -435 breast cancer cells, differential effects were documented on the expression levels of the tumor biologically relevant integrin αvß3 which colocalized with KAI1-WT but not with KAI1-SP. Cellular motility was assessed by video image processing, including motion detection and vector analysis for the quantification and visualization of cell motion parameters. In MDA-MB-231 cells, KAI1-SP provoked a quicker wound gap closure and higher closure rates than KAI1-WT, also reflected by different velocities and average motion amplitudes of singular cells. KAI1-SP induced highest cell motion adjacent to the wound gap borders, whereas in MDA-MB-435 cells a comparable induction of both KAI1 variants was noticed. Moreover, while KAI1-WT reduced cell growth, KAI1-SP significantly increased it going along with a pronounced EGF-R upregulation. KAI1-SP-induced cell migration and proliferation was accompanied by the activation of the focal adhesion and Src kinase. Our findings suggest that splicing of KAI1 does not only abrogate its tumor suppressive functions, but even more, promotes tumor biological effects in favor of cancer progression and metastasis.
A crucial mode of action of trastuzumab is the labeling of HER2-positive (HER2
) tumor cells for the eradication by natural killer (NK) cells, a process called antibody-dependent cellular ...cytotoxicity (ADCC). However, despite widespread HER2 expression among cancer entities, only a fraction, with robust HER2 overexpression, benefits from trastuzumab therapy. ADCC requires both sufficient lymphocytic infiltration and close binding of the immune cells to the antibody-tagged tumor cells. We hypothesized that the chemokine CX3CL1 could improve both processes, as it is synthesized as a membrane-bound, adhesive form that is eventually cleaved into a soluble, chemotactic protein. Here, we show that CX3CL1 overexpression is a positive prognostic marker in breast cancer. CX3CL1 overexpression attracted tumor-suppressive lymphocytes, including NK cells, and inhibited tumor growth and lung metastasis in the syngeneic 4T1 breast cancer mouse model. In HER2
SKBR3, MDA-MB-453, and HT-29 tumor cells, CX3CL1 overexpression increased NK cell-mediated cytotoxicity
and acted synergistically with trastuzumab. Even though CX3CL1 did not further improve trastuzumab efficacy
in the trastuzumab-sensitive MDA-MB-453 model, it compensated for NK-cell depletion and prolonged survival. In the HER2 low-expressing HT-29 model, however, CX3CL1 overexpression not only prolonged survival time but also overcame trastuzumab resistance in a partly NK cell-dependent manner. Taken together, these findings identify CX3CL1 as a feasible pharmacologic target to enable trastuzumab therapy in HER2 low-expressing cancers and render it a potential predictive biomarker to determine therapy responders.
e13609 Background: Precision oncology revolutionized cancer treatment by identifying molecular biomarkers to guide personalized care. The ever-growing body of medical literature presents a challenge ...for oncologists researching targeted therapies. While recent studies investigated large language models (LLMs) to streamline this process, LLM reliance on general rather than medical knowledge limits clinical relevance and trustworthiness. To address these limitations, we developed a retrieval augmented generation (RAG) system that integrates PubMed clinical studies, trial databases and oncological guidelines with LLMs to support targeted treatment recommendations. The Molecular Tumor Board (MTB) at the Center of Personalized Medicine (ZPM TUM ) guided and evaluated treatment options proposed by the LLM to assess their applicability for clinical decision support. Methods: We used 10 publicly accessible fictional patient cases with 7 tumor types and 59 distinct molecular alterations. Our LLM system MEREDITH (Medical Evidence Retrieval and Data Integration for Tailored Healthcare) consists of Google's Gemini Pro, enhanced with RAG and Chain-of-Thought (CoT) prompting. To establish a benchmark, clinical experts at ZPM TUM manually annotated the cases. Informed by MTB expert feedback, we iteratively improved our LLM system from a draft system relying on PubMed-indexed data to an enhanced system, which replicated expert annotation processes by incorporating oncology guidelines, drug availability and trial databases (ClinicalTrials.gov, QuickQueck.de). ZPM TUM assessed credibility and clinical relevance of manually annotated and LLM-generated recommendations. Patient-level data on (likely) pathogenic molecular alterations and recommended treatment options were summarized using median and interquartile range (IQR). Semantic similarity between LLM and clinician responses was assessed using cosine similarity of text vector embeddings; paired t-test evaluated significance. Results: The median of (likely) pathogenic molecular alterations per patient was 2.5 (IQR: 2-3). ZPM TUM identified a median of 2 treatment options per patient (IQR: 1-3), while the enhanced LLM identified a median of 4 (IQR: 3-5). MEREDITH proposed multiple relevant treatment suggestions, including therapies based on preclinical studies, and molecular interactions, for further assessment by the MTB. ZPM TUM prioritized the most suitable clinical option. The mean semantic textual similarity of LLM responses increased significantly from 0.69 in the draft system to 0.76 in the enhanced system (p <0.001). Thus, feedback from ZPM TUM enhanced the model's ability to align its responses with clinician thought processes. Conclusions: Leveraging expert thought processes to instruct LLMs holds promise as a novel decision support tool for precision oncology.
Fn14 is a cell surface receptor with key functions in tissue homeostasis and injury but is also linked to chronic diseases. Despite its physiological and medical importance, the regulation of Fn14 ...signaling and turnover is only partly understood. Here, we demonstrate that Fn14 is cleaved within its transmembrane domain by the protease γ‐secretase, resulting in secretion of the soluble Fn14 ectodomain (sFn14). Inhibition of γ‐secretase in tumor cells reduced sFn14 secretion, increased full‐length Fn14 at the cell surface, and enhanced TWEAK ligand‐stimulated Fn14 signaling through the NFκB pathway, which led to enhanced release of the cytokine tumor necrosis factor. γ‐Secretase‐dependent sFn14 release was also detected ex vivo in primary tumor cells from glioblastoma patients, in mouse and human plasma and was strongly reduced in blood from human cancer patients dosed with a γ‐secretase inhibitor prior to chimeric antigen receptor (CAR)‐T‐cell treatment. Taken together, our study demonstrates a novel function for γ‐secretase in attenuating TWEAK/Fn14 signaling and suggests the use of sFn14 as an easily measurable pharmacodynamic biomarker to monitor γ‐secretase activity in vivo.
Synopsis
The Tweak receptor Fn14 has a central role in tissue homeostasis, injury and tumors. The new study demonstrates that the protease γ‐secretase cleaves Fn14 within its transmembrane domain and controls Fn14 abundance, turnover and signaling. This study also establishes soluble, cleaved Fn14 as a biomarker for γ‐secretase activity in vivo.
The cell surface receptor Fn14 is a novel, but unusually short substrate for the intramembrane protease γ‐secretase.
Inhibition of γ‐secretase increases cellular and surface abundance of Fn14 and enhances it signaling in response to TWEAK ligand binding.
Soluble Fn14 may serve as an easily measurable, pharmacodynamic blood biomarker for γ‐secretase activity in vitro and in vivo.
The Tweak receptor Fn14 has a central role in tissue homeostasis, injury and tumors. The new study demonstrates that the protease γ‐secretase cleaves Fn14 within its transmembrane domain and controls Fn14 abundance, turnover and signaling. This study also establishes soluble, cleaved Fn14 as a biomarker for γ‐secretase activity in vivo.
Metabolic diversity is being studied intensively by evolutionary biologists, but so far there has been no comparison of biosynthetic pathways leading to a particular secondary metabolite in both ...prokaryotes and eukaryotes. We have detected the bioactive anthraquinone chrysophanol, which serves as a chemical defense in diverse eukaryotic organisms, in a bacterial Nocardia strain, thereby permitting the first comparative biosynthetic study. Two basic modes of folding a polyketide chain to fused-ring aromatic structures have so far been described: mode F (referring to fungi) and mode S (from Streptomyces). We have demonstrated that in eukaryotes (fungi, higher plants and insects), chrysophanol is formed via folding mode F. In actinomycetes, by contrast, the cyclization follows mode S. Thus, chrysophanol is the first polyketide synthase product that is built up by more than one polyketide folding mode.
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