Citations

Background: Integrating machine learning (ML) with population pharmacokinetic (PPK) modeling may improve therapeutic drug monitoring predictions. Methods: Tacrolimus trough concentrations from lung transplant patients were split into a training data set (1151 concentrations in 80 patients) and a testing data set (224 concentrations in 20 patients). A PPK model was developed using NONMEM, followed by the development of 10 ML models to fit individual pharmacokinetic parameters from the PPK model with Bayesian forecasting. The best performing ML model was selected as the final model. Both the final PPK and ML models were compared for prediction performance. A web-based dashboard was established with R-shiny to recommend dosing regimens based on patient data. Results: In the PPK model, postoperative days, hematocrit, aspartate aminotransferase, tacrolimus daily dose, coadministered voriconazole or posaconazole, and the CYP3A5*3 genotype were identified significant covariates on the clearance. The Cubist ML model outperformed the PPK model, showing lower root mean squared error for tacrolimus concentrations in the testing data set. An online web-based precision dosing dashboard was created, accessible at (https://tac-dose-ml.shinyapps.io/shiny/). Conclusions: Integrating ML with PPK modeling could yield superior tacrolimus concentration predictions for lung transplant patients, offering an efficient alternative to Bayesian forecasting. The online dashboard provides rapid, individualized dosing recommendations.

Chronic hepatitis B (CHB), a major global public health burden, is characterized by the presence of high circulating levels of non-infectious subviral particles (SVPs). These SVPs are mainly composed of small hepatitis B surface antigen (SHBs) and are associated with a dysfunctional HBV-specific immune response. Previous studies exploring the cellular mechanisms and molecular pathways by which SVPs are secreted from hepatocytes have utilized either non-hepatic cells or whole-genome HBV-integrated hepatoma cell lines in which SHBs can also be secreted as a component of the virion envelope. In this study, we provide a detailed examination of SHBs trafficking using biochemical approaches coupled with high-resolution confocal microscopy and live-cell imaging via a novel fluorophore-tagged SHBs probe in both HepG2 and primary human hepatocytes stably expressing SHBs. Our results provide evidence that SHBs utilize a modified ER-Golgi secretory pathway with transit from the ER to the multivesicular body and lysosomal/late endosomal compartments. Importantly, we identified the autophagy adapters ATG5 and LC3B, and the ER-phagy protein atlastin 3 (ATL3), central to mediating SHBs secretion. These findings suggest that SHBs is trafficked through a non-canonical path for secretion and provides new potential therapeutic targets for the treatment of CHB.

Abstract Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy due in part to metabolic rewiring and a high rate of metastasis. Pancreatic tumors are particularly dependent upon glutamine (Gln) as a nutrient source for multiple metabolic pathways. To adapt to low levels of glutamine, PDAC cells upregulate the Rac1 dependent process of macropinocytosis, which internalizes extracellular macromolecules to scavenge them as a glutamine source. The proto oncogene Vav1 is an activator of the potent Rac/Cdc42 signaling cascades that regulate actin dynamics. While Vav1 is normally restricted to hematopoietic cells, Vav1 expression is significantly increased in PDAC, with high Vav1 correlating with worse overall survival. Here we uncover a novel Vav1 mediated regulation of glutamine metabolism in PDAC cells. While Vav1 is a potent activator of Rac1, surprisingly, Vav1 expression inhibited macropinocytosis in PDAC cells. Intriguingly, genomic and metabolomic analysis revealed that high Vav1 expression correlates with increased dependence on glutamine and glutamate (Glu) metabolism. Indeed, Vav1 dependent macropinocytosis was rescued by cell permeable glutamate, confirming disrupted Gln/Glu balance in Vav1 knockdown cells. RPPA screening indicated a Vav1 dependent effect on glutaminase 1 (GLS1, KGA isoform), which converts glutamine to glutamate. Mechanistically, we discovered that Vav1 modulates GLS1 localization to the mitochondria through regulation of GLS1 posttranslational modification. Disrupting GLS1 localization by deleting its mitochondrial targeting motif phenocopied loss of Vav1 in reducing the invasive potential of tumor cells. Investigation of Vav1 dependent metabolic consequences showed that knockdown of Vav1 alters 13C Gln derived metabolic flux into the TCA cycle, as well as a deficiency in the level of the antioxidant glutathione (GSH), which utilizes glutamate for its synthesis. Consequently, targeting Vav1 resulted in increased levels of cellular and mitochondrial reactive oxygen species (ROS) and increased sensitivity to lipid peroxidation. Notably, dual targeting of both glucose and glutamine pathways showed significant synergistic effects on cellular viability in Vav1 expressing cells. Here we established a new tumor promoting role for Vav1 via Gln/Glu regulation and uncover a novel subcellular regulation of mitochondrial glutamine metabolism. Our findings establish Vav1 as a critical regulator of metabolic rewiring in PDAC and orchestrates glutamine metabolism by controlling the KGA isoform of GLS1 mitochondrial localization. Importantly, Vav1 functions as a signaling adapter in glutamine metabolism, providing a potential therapeutic vulnerabilities for PDAC patients with high Vav1 expression. Citation Format: Mustafa Emre Gedik, Omar L. Gutierrez-Ruiz, Katherine M. Johnson, Ella Rose D. Chianis, Jing Chen, Alex Bittner, Adam Zahm, Ankit Chhoda, Taro Hitosugi, Mark A. McNiven, Gina Razidlo. Vav1 promotes pancreatic tumor cell invasion via GLS1-dependent glutamine metabolism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7322.

It is well established that many tumor types possess defective autophagic pathways. Several studies have reported that the transmembrane, autophagic lipid scramblase ATG9B is altered in multiple cancers, suggesting that this dysregulation could contribute to oncogenesis. Therefore, the goal of this study was to define the cellular distribution of ATG9B in two different tumor cell types and to provide insights into its cellular function. Surprisingly, we found that ATG9B shows a modest association with autophagic structures and exhibits a unique and prominent localization to mitochondria, in contrast to its related form ATG9A. Upon expression of tagged ATG9B forms, this mitochondrial distribution was accompanied by aberrant changes in mitochondrial morphology as well as a reduction in the mitochondrial membrane potential and the release of mtDNA. Few indicators for ATG9B-dependent mitophagy were noted. Instead, ATG9B overexpression led to pronounced apoptotic cell death as assessed by a variety of indicators. Further, we find that the N-terminal sequence of ATG9B acts as a mitochondrial targeting domain and that expression of this peptide alone can induce apoptotic cell death. These findings provide new insights into a putative cellular localization and function for ATG9B.

BACKGROUND We constructed multi-trait polygenic risk scores (PRSs) predicting chronic obstructive pulmonary disease (COPD) and exacerbations, validated their performance in diverse cohorts, and identified PRS-related proteins for potential therapeutic targeting. METHODS PRSmix + , a multi-trait PRS framework, is used to train a composite PRS (PRS multi ) in COPDGene non-Hispanic White participants ( n = 6,647). Associations of PRS multi with COPD status (GOLD 2–4 vs. GOLD 0 or ICD) and exacerbation frequency were tested in COPDGene African American ( n = 2,466), ECLIPSE ( n = 1,858), Mass General Brigham Biobank ( n = 15,152), and All of Us ( n = 118,566). Protein prediction models were applied to GWAS summary statistics from traits contributing to PRS multi and were validated with proteomic data in COPDGene ( n = 5,173) and UK Biobank ( n = 5,012). RESULTS PRSmix + selected 7 traits for PRS multi . In multivariable models, PRS multi was associated with COPD status (meta-analysis random effects [RE] OR 1.58 [95% CI: 1.28–1.94]) and exacerbation frequency (meta-analysis RE β 0.21 [95% CI: 0.11–0.31]), with higher effect sizes observed in smoking-enriched cohorts. PRS multi outperformed traditional single-trait PRS in all tested cohorts. Using protein prediction models, we identified 73 proteins associated with the PRSs that were also validated with measured protein levels in COPDGene and UK Biobank. Of these proteins, 25 were linked to approved or investigational drugs. Notable targets include RAGE/sRAGE, IL1RL1, and SCARF2, all implicated in COPD pathogenesis and exacerbations. CONCLUSIONS Multi-trait PRS improves prediction of COPD and exacerbation risk. Integration with proteomic data identifies druggable protein targets, offering a promising avenue for precision medicine in COPD management. TRIAL REGISTRATION COPDGene: ClinicalTrials.gov NCT00608764; ECLIPSE: ClinicalTrials.gov NCT00292552.

This paper summarizes the presentations and panel discussion provided at Plenary Panel #2 on the first day of the 16 th World Congress of the International Radiation Protection Association (IRPA) jointly organized with the 69th Annual Meeting of the Health Physics Society (HPS) in Orlando/Florida in July 2024. International organizations that play a key role in radiation protection and are close in contact with IRPA by official agreements or even MoU’s (Memorandum of Understanding) presented highlights of their projects in radiation protection as well as results. Topical issues on their current work program as seen in a list of statements, including future efforts, were presented and discussed. The needs of practitioners were stressed for recognition by the representatives of the international organizations to be included in their projects. Requested and presented topics were: • Key challenges for radiation protection practitioners in the next 10 y. • Potential effects of emerging science on radiation protection. • Challenges for implementation of IAEA Safety Standards in low- and middle-income countries. • Challenges in occupational radiation protection. • Broadening the process of optimization. • Impact of emerging technologies on radiation protection. • Ensuring radiation protection workforce for the future.

Abstract Immune checkpoint inhibitor (ICI) therapy has significantly advanced cancer treatment, particularly for metastatic melanoma, but it is associated with severe, life-threatening adverse effects. A rare but critical complication is the overlap syndrome of Myositis, Myocarditis, and Myasthenia Gravis (MMM), affecting approximately 0.21% of ICI-treated solid tumor patients with an in-hospital mortality rate of up to 60%. Early recognition and management are crucial for improving outcomes. Case Presentation: A 76-year-old male with metastatic melanoma, coronary artery disease, ischemic cardiomyopathy (EF 35%), chronic kidney disease, diabetes, and chronic respiratory failure (baseline oxygen requirement of 2L) presented two weeks after starting Nivolumab and Relatlimab. He developed worsening exertional dyspnea, orthopnea, diplopia, dysarthria, and progressive proximal muscle weakness. On presentation, he was hemodynamically stable, with elevated troponin T (1241 ng/L) and NT-proBNP (2698 pg/mL). Initial investigations, including EKG and chest X-ray, were unremarkable with no thymoma. Left heart catheterization revealed severe multivessel coronary artery disease but no treatable lesions. He was noted to have fatigable ptosis and he subsequently developed bulbar symptoms, including hypophonia and dysphagia. A diagnosis of Myasthenia Gravis was suspected. Further evaluation showed respiratory muscle weakness (NIF -12 cm H2O, vital capacity 2L, mild hypercarbia on ABG) and progressive weakness, leading to intubation. Elevated creatine kinase (1527 U/L), persistent troponin elevation, and global hypokinesis on repeat echocardiography pointed to a likely diagnosis of myocarditis/myositis. Electromyography revealed neuropathy without acute findings, and serological testing for acetylcholine receptor antibodies, HMG-CoA reductase antibodies, and myositis was negative. ICI-induced MMM was diagnosed, and the patient was treated with methylprednisolone, IVIG, pyridostigmine, and ICI discontinuation. Despite plasmapheresis, his condition deteriorated. He developed septic shock from multiple infections (E-Coli bacteremia, Stenotrophomonas pneumonia) and progressed to cardiogenic shock, requiring vasopressors. Subsequent imaging revealed pneumoperitoneum concerning bowel perforation, but further diagnostic workup was declined by the family. Comfort care was initiated, and the patient passed away. Discussion: ICI use has grown rapidly, with agents like Nivolumab expanding treatment options for metastatic melanoma. However, MMM, a rare but severe complication, demands prompt recognition. Presentation often occurs within 21 days of ICI initiation, and patients may display elevated CPK and stable or rising troponin levels. Myasthenia gravis within MMM can cause rapid respiratory failure, with significant morbidity. Management includes corticosteroids, IVIG and immediate ICI discontinuation. Treatment should begin without waiting for confirmatory tests, given the syndrome's high mortality. Early, multidisciplinary intervention is essential in managing this fatal condition effectively.

Rab32 is a small GTPase and molecular switch implicated in vesicular trafficking. Rab32 is also an A-Kinase Anchoring Protein (AKAP), which anchors cAMP-dependent Protein Kinase (PKA) to specific subcellular locations and specifies PKA phosphorylation of nearby substrates. Surprisingly, we found that a form of Rab32 deficient in PKA binding (Rab32 L188P) relocalized away from the Golgi apparatus and induced a marked disruption in Golgi organization, assembly, and dynamics. Although Rab32 L188P did not cause a global defect in PKA activity, our data indicate that Rab32 facilitates the phosphorylation of a specific PKA substrate. We uncovered a direct interaction between Rab32 and the adaptor protein optineurin (OPTN), which regulates Golgi dynamics. Further, our data indicate that optineurin is phosphorylated by PKA at Ser342 in a Rab32-dependent manner. Critically, blocking phosphorylation at OPTN Ser342 leads to Golgi fragmentation, and a phospho-mimetic version of OPTN rescues Golgi defects induced by Rab32 L188P. Finally, Rab32 AKAP function and OPTN phosphorylation are required for Golgi repositioning during cell migration, contributing to tumor cell invasion. Together, these data reveal a role for Rab32 in regulating Golgi dynamics through PKA-mediated phosphorylation of OPTN.

Abstract Background The majority of patients with prostate cancer (PCa) exhibit intrinsic resistance to immune checkpoint blockade (ICB) following radiotherapy (RT). This resistance is generally attributed to the limited antigen presentation of heterogeneous cells within tumors. Here, we aimed to isolate and characterize these diverse subgroups of tumor post‐RT to understand the molecular mechanisms of their resistance to ICB. Methods Single‐cell RNA‐sequencing (scRNA‐seq) was used to profile senescent cancer cell clusters induced by RT in LNCaP cells. The expression and phosphorylation levels of ataxia telangiectasia and Rad3‐related protein (ATR) were assessed by immunohistochemistry in clinical samples from patients with or without RT. Co‐immunoprecipitation, mutagenesis, and Western blotting were used to measure the interactions between proteins. Xenograft experiments were performed to assess the tumor immune response in the mice. Results We identified a subset of PCa cells that exhibited resistance to RT, characterized by a reduced antigen presentation capability, which enhanced their ability to evade immune detection and resist cytotoxic T‐lymphocyte‐associated protein 4 (CTLA‐4) blockade. scRNA‐seq revealed that the senescent state was a transient phase of PCa cells post‐RT, particularly in CTLA‐4 blockade treatment‐resistant cells. This state was marked by increased cytosolic ATR level. Cytosolic ATR phosphorylated CD86 in its cytosolic domain and enhanced the interaction between CD86 and its E3 ligase MARCH1 through electrostatic attraction. Depletion or inhibition of Atr increased the sensitivity to immune attack and improved responses to anti‐Ctla‐4 antibody treatment in a mouse model. Conclusions Our findings indicate that the activation of cytosolic ATR, which is associated with cellular senescence, impedes the effectiveness of combined RT and ICB treatments. This discovery may provide valuable insights for improving the efficacy of combined RT and ICB therapies in PCa.

Background: Despite the growing interest in the role of isolated left ventricular (LV) diastolic dysfunction in cardiac remodeling, little is known about its association with cognitive performance in midlife, prior to the onset of dementia. Hypothesis: We hypothesized that LV diastolic dysfunction and cardiac remodeling will be associated with cognitive performance in middle-aged adults. These associations might differ by sex and race. Aim: To investigate the impact of left atrial (LA) size, LV mass, volume, systolic and diastolic function on cognition in middle-aged Black and White, men and women from a rural, community-based cohort, the Bogalusa Heart Study (BHS), in Louisiana. Methods: A total of 1,107 participants from the BHS (48.1±5.4 years, 56.7% female, 34.3% black) with echocardiography and cognitive testing were included. Cognitive performance was quantified in a global cognitive score (GCS) comprised of the z standardized sum of 7 neuropsychiatric tests. Multivariate linear regression analysis was used for the association of E/e’, LA volume index (LAVi), LV end-diastolic volume (LVEDV), mass index (LVMi) as well as ejection fraction (LVEF) with GCS adjusted for age, sex, race, systolic and diastolic blood pressure, total and HDL cholesterol, history of smoking, diabetes, and hypertension as well as education. Interactions by sex and race were tested. Results: Even after adjusting for age, sex and race, larger LAVi, LVEDV, LVMi, higher E/e’ and lower e’ were associated with poorer cognitive function (all p <0.05), but not LVEF. These associations remained significant for E/e’, e’, and LVMi after adjusting for systolic and diastolic blood pressure, total and HDL cholesterol, history of smoking, diabetes, hypertension, as well as education. There was no significant race interaction. In contrast, the association of E/e’ with GCS was significantly stronger (standardized β coefficient =-0.20; p <0.01) in middle-aged women, but not in middle-aged men (standardized β coefficient =-0.04; p <0.36; p interaction=0.02). Conclusion: LV diastolic function is more closely associated with mid-life cognition than systolic function, and the association is present among middle aged women but not men.