GM-CSF induces proinflammatory macrophages, but the underlying mechanisms have not been studied thus far. In this study, we investigated the mechanisms of how GM-CSF induces inflammatory macrophages. First, we observed that GM-CSF increased the extent of LPS-induced acute glycolysis in murine bone marrow–derived macrophages. This directly correlates with an inflammatory phenotype because glycolysis inhibition by 2-deoxyglucose abolished GM-CSF–mediated increase of TNF-α, IL-1β, IL-6, and IL-12p70 synthesis upon LPS stimulation. Increased glycolytic capacity is due to de novo synthesis of glucose transporter (GLUT)-1, -3, and -4, as well as c-myc. Meanwhile, GM-CSF increased 3-hydroxy-3-methyl-glutaryl-CoA reductase, which is the rate-limiting enzyme of the mevalonate pathway. Inhibition of acute glycolysis or 3-hydroxy-3-methyl-glutaryl-CoA reductase abrogated the inflammatory effects of GM-CSF priming in macrophages. Finally, mice with inflamed colons exposed to dextran sodium sulfate containing GLUT-1^high macrophages led to massive uptake of [¹⁸F]-fluorodeoxyglucose, but GM-CSF neutralization reduced the positron-emission tomography signal in the intestine and also decreased GLUT-1 expression in colonic macrophages. Collectively, our results reveal glycolysis and lipid metabolism created by GM-CSF as the underlying metabolic constructs for the function of inflammatory macrophages.

Radioiodine whole body scan (WBS), related to sodium iodide symporter (NIS) function, is widely used to detect recurrence/metastasis in postoperative patients with thyroid cancer. However, the normal thymic uptake of radioiodine has occasionally been observed in young patients. We evaluated the expression of thyroid-related genes and proteins in the human thymus. Thymic tissues were obtained from 22 patients with thyroid cancer patients of all ages. The expression of NIS, thyroid-stimulating hormone receptor (TSHR), thyroperoxidase (TPO), and thyroglobulin (Tg) was investigated using immunohistochemistry and quantitative RT-PCR. NIS and TSHR were expressed in 18 (81.8%) and 19 samples (86.4%), respectively, whereas TPO was expressed in five samples (22.7%). Three thyroid-related proteins were localized to Hassall’s corpuscles and thymocytes. In contrast, Tg was detected in a single patient (4.5%) localized to vascular endothelial cells. The expression of thyroid-related proteins was not increased in young thymic tissues compared to that in old thymic tissues. In conclusion, the expression of NIS and TSHR was detected in the majority of normal thymus samples, whereas that of TPO was detected less frequently, and that of Tg was detected rarely. The increased thymic uptake of radioiodine in young patients is not due to the increased expression of NIS.

Improved therapeutic strategies are required to minimize side effects associated with radioiodine gene therapy to avoid unnecessary damage to normal cells and radiation-induced secondary malignancies. We previously reported that codon-optimized sodium iodide symporter (oNIS) enhances absorption of I-131 and that the brahma-associated gene 1 bromodomain (BRG1-BRD) causes inefficient DNA damage repair after high-energy X-ray therapy. To increase the therapeutic effect without applying excessive radiation, we considered the combination of oNIS and BRG1-BRD as gene therapy for the most effective radioiodine treatment. The antitumor effect of I-131 with oNIS or oNIS+BRD expression was examined by tumor xenograft models along with functional assays at the cellular level. The synergistic effect of both BRG1-BRD and oNIS gene overexpression resulted in more DNA double-strand breaks and led to reduced cell proliferation/survival rates after I-131 treatment, which was mediated by the p53/p21 pathway. We found increased p53, p21, and nucleophosmin 1 (NPM1) in oNIS- and BRD-expressing cells following I-131 treatment, even though the remaining levels of citrulline and protein arginine deiminase 4 (PAD4) were unchanged at the protein level.

The lack of standard systemic treatments in meningioma presents a therapeutic challenge, making radiotherapy a crucial intervention for recurrent, high-grade, or inoperable tumours. Nonetheless, the efficacy of radiotherapy is constrained by the inherent radioresistance of meningiomas, attributed to their proficient DNA damage repair and robust cell cycle checkpoint regulation. These biological barriers, along with anatomical constraints of avoiding damage to adjacent neural tissues, restrict dose escalation and therapeutic gains. Histone deacetylases (HDACs) are mediators of radioresistance in meningioma, and their inhibition can be a rational approach to enhance the therapeutic efficacy. This study systematically investigated the radiosensitising potential of dacinostat, a pan-HDACi, and demonstrated its superior synergy with radiation compared to other FDA-approved HDACis. Pre-treatment with dacinostat effectively suppressed radiation-induced HDAC activity, resulting in sustained DNA damage, prolonged G2/M arrest, and enhanced apoptosis. Mechanistic analyses revealed that radiosensitisation was associated with RAD51 downregulation, inhibition of DNA-PKcs activity, modulation of p53 phosphorylation, and attenuation of SUMOylation-dependent DNA repair signalling. Transcriptomic profiling underscored cell-cycle regulation and DNA-repair pathways in response to combination treatment. Meanwhile, proteomic data implicated the modulation of SUMOylation as a central mediator of the observed radiosensitisation. Importantly, in physiologically relevant 3D spheroid models derived from patient meningioma specimens, the combined treatment synergistically augmented cell death, supporting the translational potential of this therapeutic strategy. Overall, this work establishes dacinostat as a promising radiosensitiser that compromises DNA repair fidelity and moduflates SUMOylation-associated pathways, thereby enhancing efficacy in treatment-resistant meningiomas. These findings provide a compelling preclinical basis to advance dacinostat into clinical assessment for the management of aggressive meningioma.

Supplementary Figure S6. Immunohistochemistry confirms that BRG1-BRD is expressed in the xenografted tumor cells throughout the time course analyzed.

Supplementary Figure S4. BRG1-BRD inhibits γ-H2AX formation and DSB repair in irradiated A549 cells and this activity is enhanced by dimerization.