Aim: The exact pathomechanism of GNE myopathy remains elusive, but likely involves aberrant sialylation. We explored sialylation status of blood-based glycans as potential disease markers. Methods: We employed immunoblotting, lectin histochemistry and mass spectrometry. Results: GNE myopathy muscle showed hyposialylation of predominantly O-linked glycans. The O-linked glycome of patients' plasma compared with controls showed increased amounts of desialylated Thomsen–Friedenreich (T)-antigen, and/or decreased amounts of its sialylated form, ST-antigen. Importantly, all patients had increased T/ST ratios compared with controls. These ratios were normalized in a patient treated with intravenous immunoglobulins as a source of sialic acid. Discussion: GNE myopathy clinical trial data will reveal whether T/ST ratios correlate to muscle function. Conclusion: Plasma T/ST ratios are a robust blood-based biomarker for GNE myopathy, and may also help explain the pathology and course of the disease.
Drug resistance can evolve from a subpopulation of cancer cells that initially survive drug treatment and then gradually form a pool of drug-tolerant cells. Several studies have pinpointed the activation of a specific bypass pathway that appears to provide the critical therapeutic target for preventing drug tolerance. Here, we take a systems-biology approach, using proteomics and genomics to examine the development of drug tolerance to EGFR inhibitors in EGFR-mutant lung adenocarcinoma cells and BRAF inhibitors in BRAF-mutant melanoma cells. We found that there are numerous alternative mitogenic pathways that become activated in both cases, including YAP, STAT3, IGFR1, and phospholipase C (PLC)/protein kinase C (PKC) pathways. Our results suggest that an effective therapeutic strategy to prevent drug tolerance will need to take multiple alternative mitogenic pathways into account rather than focusing on one specific pathway.
Background/Objectives: Pyrogens, fever-inducing substances from biological or environmental sources, are recognized by Toll-like receptors (TLRs) predominantly expressed by human monocytes and represent a critical quality attribute (CQA) for pharmaceutical safety. The rabbit pyrogen test (RPT), widely used for pyrogen assessment, suffers from high variability, limited accuracy, and poor reproducibility, particularly for vaccines containing inherent pyrogens such as outer membrane protein complex (OMPC)-based vaccines. Existing in vitro alternatives using peripheral blood mononuclear cells (PBMCs) are challenged by donor-to-donor variability and the operational complexity of ELISA readouts. To support the 3Rs (Refinement, Reduction, Replacement) and provide a more reliable quality control (QC) method, we developed a reporter cell–based monocyte activation test (MAT) suitable for release testing. Methods: We screened human monocytic reporter cell lines engineered with NFκB-responsive promoter elements driving a luminescent reporter. Reporter cells were treated with diverse endotoxin and non-endotoxin pyrogens and luminescence was quantified after stimulation. Selected THP-1-derived reporter cells were used to develop an MAT for OMPC. Assay performance was evaluated following validation guidelines: linearity, accuracy, precision, analytical range (relative to a reference lot), and robustness under deliberate parameter variations. Results: The THP-1 reporter cells could detect a wide range of pyrogens via simple luminescence readouts. For OMPC testing, the MAT demonstrated strong linearity (R2 ≥ 0.99), accuracy with relative bias within ±10.3%, and high precision (overall %RSD ≤ 6.9%) across the 25–300% range. Deliberate variations in assay parameters did not materially affect performance, indicating robustness appropriate for routine release testing. Conclusions: The implementation of reporter cell-based MAT assays enhances consistency, reliability, and efficiency in evaluating the pyrogenicity and safety of drug products, supporting global initiatives to minimize animal testing while ensuring regulatory compliance.
Drug resistance continues to be a major obstacle to curing cancer. Resistance can evolve from a subpopulation of cancer cells that initially survive drug treatment and then gradually form a pool of slowly growing drug-tolerant cells. Several studies have pinpointed activation of a specific bypass pathway that appears to provide the critical therapeutic target for preventing drug tolerance. Here we take a systems-biology approach using proteomics and genomics to examine the development of drug tolerance to EGFR inhibitors in EGFR-mutant lung adenocarcinoma cells and BRAF inhibitors in BRAF-mutant melanoma cells. We found that there are numerous alternative mitogenic pathways that become activated in both cases, including YAP, STAT3, IGFR1, and phospholipase C (PLC)/protein kinase C (PKC) pathways. Our results suggest that an effective therapeutic strategy to prevent drug tolerance will need to take multiple alternative mitogenic pathways into account rather than focusing on one specific pathway.