Citations

Abstract Pancreatic ductal adenocarcinoma (PDAC) is unresponsive to immune checkpoint therapies largely due to immunosuppression mediated by myeloid and lymphoid cells. Effective treatment strategies require, in addition to immune stimulation, the depletion of these immunosuppressive cells and their interactions. Here, we demonstrate for the first time, that a single verteporfin-based photodynamic therapy (PDT) treatment triples median survival in a KPC-PDAC model when combined with anti-PD1 therapy. Mechanistically, apart from reducing CK19 + tumor cells, PDT depletes immunosuppressive myeloid (CD11c+) and lymphoid (FOXP3+) cell populations, by ~ 4- and ~ 18.4-folds, respectively. PDT further disrupts interactions between these immunosuppressive cells, attenuating a key immune-tolerance axis. At the systemic level, PDT reduces splenic immunosuppression through modulation of tumor-derived cytokines. Within this reprogrammed immune-landscape, anti–PD-1 therapy elicits robust CD8 + T-cell responses, reflected by an ~ 6.7-fold increase in the intratumoral CD8+/Treg ratio. Collectively, these findings establish verteporfin-PDT as an immune-priming strategy that complements anti–PD-1 therapy by alleviating immunosuppression in PDAC.

Abstract Although CD8+ T cells face intense immunosuppressive and metabolic pressures within the tumor microenvironment (TME), a subset of these cells can mount resilient responses to immune checkpoint inhibitor (ICI) therapy. We recently identified a population of such resilient CD8+ T cells in patients with advanced solid tumors who were unresponsive to standard-of-care cancer therapies but showed clinical benefit from ICI or combination ICI therapy. Among these resilient CD8+ T cells, which retain their cytotoxic capacity to eliminate tumor cells, we observed upregulation of ME1 and downregulation of DUSP2 in responders to the combination therapy. However, the mechanistic role of altered ME1 and DUSP2 expression in shaping resilient CD8+ T cell responses in cancer remains to be fully elucidated. To that end, we used scRNA-seq, bulk RNA-seq, and ATAC-seq analyses to investigate how altered expression of DUSP2 and ME1 regulates transcription of genes encoding effector molecules in both human and mouse CD8+ T cells. Additionally, we utilized CD8+ T cell-specific DUSP2 knockout (KO) and ME1 transgenic (Tg) mouse models to define the roles of these genes in effector T cell differentiation and antitumor responses in vivo. We found that DUSP2 downregulation enhances the expression of effector molecules (e.g., GZMB and NKG7) in CD8+ T cells, accompanied by increased cytotoxic activity. Mechanistically, reduced DUSP2 expression promotes chromatin accessibility at effector gene loci by modulating the nuclear residency balance between BAF and NuRD, two chromatin remodeling complexes with opposing functions. In parallel, ME1 overexpression enables activated CD8+ T cells to bypass the classical glycolysis pathway in favor of the pentose phosphate pathway (PPP), thereby boosting ATP production while minimizing excess ROS accumulation and increasing effector molecule expression via an epigenetic mechanism. Our study reveals a previously unknown adaptive mechanism by which resilient CD8+ T cells maintain their cytotoxic function within the TME. This is achieved through integrated reprogramming of epigenetic regulation and metabolic fitness, enabling compensation for metabolic stress in the TME and restoration of responsiveness to ICI-based combination therapy, even in patients with substantial tumor burden. Citation Format: Haidong Dong. Epigenetic and metabolic reprogramming for resilient CD8+ T cell responses in the tumor microenvironment [abstract]. In: Proceedings of the AACR Immuno-Oncology Conference (AACR IO): Discovery and Innovation in Cancer Immunology: Revolutionizing Treatment through Immunotherapy; 2026 Feb 18-21; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Immunol Res 2026;14(2 Suppl):Abstract nr A001.

Background Monensin, a Na + ionophore, can increase cytosolic Ca 2+ ([Ca 2+ ] i ) by reversing the Na + /Ca 2+ exchange mechanism. This study provided additional insights into the mechanism of this Na + ionophore-induced increase in [Ca 2+ ] i , and emphasized the critical role of phospholipase C (PLC) in amplifying Na + /Ca 2+ exchange-induced Ca 2+ influx and subsequent arachidonic acid (AA) release in FRTL-5 thyroid cells. The possible involvement of protein kinase C (PKC), mitogen-activated protein kinase (MAPK), and GTP-binding (G) protein in mediating monensin-induced AA release was also explored. Methods FRTL-5 thyroid cells were maintained in Coon's modified Ham's F-12 medium supplemented with a 6-hormone (6H) mixture. Cytosolic Ca 2+ was measured by using indo-1 AM and a dual-wave-length spectrofluorometer. Release of 3 H-labeled inositol trisphosphates and arachidonic acid were determined by a scintillation counter. Results In Hank's balanced salt solution with Ca 2+ (HBSS+), monensin (100 µmol/L) induced a 2.3-fold sustained Ca 2+ increase associated with IP 3 generation and a 6-fold increase in AA release. Deletion of extracellular Ca 2+ , or replacement of Na + by choline chloride in the medium, reduced the [Ca 2+ ] i increase by 77% and completely prevented the monensin-induced rise in AA release. Similar inhibitory effects were observed in cells pretreated with a Na + channel blocker, or Na + /Ca 2+ exchange inhibitors. In HBSS without Ca 2+ (HBSS-), monensin induced a 1-fold transient [Ca 2+ ] i increase but did not increase the AA. This Ca 2+ increase was not suppressed by U-73122, a PLC inhibitor. In HBSS+, U-73122 did not affect the monensin-induced initial transient peak increase of [Ca 2+ ] i , but reduced the sustained second phase of [Ca 2+ ] i from 400 nmol/L to 250 nmol/L, and completely blocked AA release. A phospholipase A 2 (PLA 2 ) inhibitor blocked the monensin-induced AA release without affecting the [Ca 2+ ] i increase. Inhibition of PKC prevented 87% to 94% of the monensin-stimulated AA release. The monensin-induced AA release was also inhibited 94% by pertussis and 51% by a MAP kinase cascade inhibitor. Conclusions The results suggest that monensin initiates an increase in [Ca 2+ ] i via a Na + /Ca 2+ exchange mechanism that triggers more pronounced and sustained [Ca 2+ ] i increase via activation of PLC and Ca 2+ influx. The PLC activation, followed by sustained Ca 2+ influx and PKC activation, is a prerequisite for PLA 2 -mediated processes in monensin-challenged FRTL-5 thyroid cells. Key words: FRTL-5 thyroid cells • phospholipases • protein kinase C • MAP kinase • cell calcium

Abstract Background Left atrial appendage (LAA) closure or amputation is commonly performed in atrial fibrillation (AF) patients undergoing cardiac surgery to reduce stroke risk. It has been shown that LAA closure or amputation results in persistent blood pressure (BP) decrease, which may be due to a surge in atrial natriuretic peptide (ANP) and by suppression of sympathetic activity due to activation of mechanoreceptors by atrial distention. We hypothesize that size of the LAA, a compliant structure, affects atrial distension. Consequently, patients with smaller LAA remnants (i.e. more complete amputation) have more distension of the atrium and a more pronounced BP response upon LAA amputation. Methods We analyzed 33 patients with persistent AF from the MARK AF registry who underwent LAA amputation concomitant to thoracoscopic AF ablation. Systolic BP was measured at baseline, 12 hours (h), 24h, and 48h, 1 month, 1 year, and 2 years postoperatively. Complete amputation was defined as LAA remnant depth <10mm and a remnant LAA was defined as depth ≥ 10 mm on contrast enhanced CT 6 months post surgery. The postoperative LAA remnant/LA volume ratio was calculated by segmenting the atria and quantifying the volume of the contrast pools. T-tests and linear regression analyzed BP changes by remnant size and LAA remnant/LA volume ratio. Results were visualized using a boxplot and scatter plots with regression lines. Results 25/33 Patients had a LAA remnant. Baseline systolic BP was similar with 147 ± 31 mmHg in the complete amputation group vs. 137 ± 23 mmHg in the remnant group, p=0.389. Complete amputation correlated with greater systolic BP reductions in relation to baseline at 12h (-18%, p=0.018), 24h (-14%, p=0.025), 48h (-15%, p=0.028), 1 month (-20%, p=0.024), and 1 year (-16%, p=0.001), Figure 1. BP returned to baseline by 2 years in both groups. Lower LAA remnant/LA volume ratios were significantly associated with greater systolic BP reductions at 12h (β=7.4, p=0.005), 24h (β=9.9, p<0.001), 48h (β=10.1, p=0.002), and 1 month (β=11.1, p=0.01), Figure 2. However, this association was not observed at 1 and 2 years. Conclusion Patients with smaller LAA remnants after LAA amputation experienced a more pronounced transient reduction in blood pressure. Our findings suggest that increased atrial distension—due to the loss of compliant LAA tissue—could play a key role in modulating hemodynamics via sympathoinhibition and suppression of the Renin-Angiotensin-Aldosterone System (RAAS). Further investigation is needed to confirm these results and explore the neurohumoral effects of LAA amputation.Figure 1 Figure 2

Ramdas et al. propose renaming ‘congenital myasthenic syndrome’ as ‘genetic myasthenic syndrome’. They argue that ‘congenital’ misleadingly implies neonatal onset, which may contribute to delayed diagnosis and management, and that revised nomenclature could improve patient outcomes.

Background: Cardiac CT acquired during the acute stroke imaging protocol is an emerging diagnostic modality to detect cardiac thrombi. We aimed to determine its diagnostic yield in a large, international, multicenter study. Methods: We performed an individual patient data meta-analysis by pooling prospective and retrospective observational data of patients with acute ischemic stroke (AIS) who underwent cardiac CT (ECG-gated or non-ECG-gated) as part of the acute imaging protocol between May 2018 and June 2024. We excluded patients with a TIA or stroke mimic. The primary outcome was the proportion of patients with a cardiac thrombus detected on cardiac CT. Secondary outcomes were additional scan time and radiation dose, comparison of yield with echocardiography, and 90-day mortality and recurrent ischemic stroke rates. Results: We included 3940 patients from 4 hospitals (median age 74 [IQR 63-82], 58.0% male, median NIHSS 6 [IQR 3-12], median time onset to hospital arrival 100 minutes [IQR 62-185]). Atrial fibrillation at baseline was present in 23.1% patients, and 29.6% had a large vessel occlusion. Cardiac CT was non-diagnostic in 17 (0.4%) patients. In total, cardiac CT detected 254 cardiac thrombi in 243/3923 (6.2%) patients. Thrombi were located in the left atrial appendage (n=193), left atrium (n=19), and left ventricle (n=42). Of 95/243 (39.1%) patients with a cardiac thrombus that underwent echocardiography (median interval cardiac CT-echocardiography: 2 days), transthoracic echocardiography detected a thrombus in 18/92 (19.6%) patients and transesophageal echocardiography in 2/5 (40.0%) patients. The diagnostic yield in patients that underwent both modalities was higher for cardiac CT (OR 7.5 [CI 4.0-15.3], p<0.001). Median additional scan time was 6 minutes (IQR 5-7) for ECG-gated and 17 seconds (IQR 15-63) for non-ECG-gated cardiac CT. Median additional radiation dose was 5.4mSv (IQR 3.0-7.6). Patients with a cardiac thrombus on cardiac CT had higher 90-day mortality than those without a thrombus (33.3% vs 14.6%, p<0.001). We found no difference in 90-day recurrent stroke rate (5.4% vs 4.4%, p=0.50). Conclusion: Routine cardiac CT performed during the acute stroke imaging protocol detects a cardiac thrombus in 1 out of 16 patients with AIS, with a 7-times higher yield than routine echocardiography. Mortality rate was doubled in patients with a cardiac thrombus, but 90-day stroke recurrence risk did not differ.

Background: The rate of intracardiac thrombus detection in the hyperacute phase of stroke varies from 5% to 12% between studies. Our aim was to compare the thrombus detection rate between ECG-gated and non-ECG-gated cardiac CT protocols in acute stroke patients, using data from a large, international, multicentre registry. Methods: We conducted an individual patient data meta-analysis by pooling prospective and retrospective observational data from stroke patients assessed at four comprehensive stroke centres who underwent either ECG-gated or non-ECG-gated cardiac CT (extended CT angiography or two-phase non-ECG-gated cardiac CT) as part of the acute stroke imaging protocol between May 2018 and June 2024. The primary outcome was the proportion of patients with a cardiac thrombus in gated vs non gated techniques. Results: Of 3,940 patients, 1,474 (37.4%) underwent ECG-gated and 2,466 (62.6%) non-ECG-gated cardiac CT. Patients in the ECG-gated group were younger (median age 72 [IQR 62–81] vs. 74 [IQR 64–82] years, p = 0.000) and had a lower NIHSS at baseline (median 5 [IQR 2–12] vs. 6 [IQR 3–13], p < 0.00). There was a higher rate of thrombus detection with ECG-gated CT compared to non-gated CT (7.5% vs. 5.5%, p = 0.011. The association remained significant after adjusting for age, sex, baseline NIHSS score, and baseline atrial fibrillation (adjusted OR 1.87, 95% CI 1.42–2.47, p = 0.000). ECG-gated CT was associated with lower radiation dose (3.6 vs. 6.3 mSv, p = 0.000) but longer acquisition time (5.8 vs. 0.28 min, p = 0.000). Conclusion: ECG-gated cardiac CT has a higher detection rate for intracardiac thrombus detection compared to non-ECG-gated CT in patients with acute ischemic stroke.

ABSTRACT The limited efficacy of current therapies against cholangiocarcinoma (CCA) necessitates the development of novel treatment strategies. Src family kinases (SFKs) contribute significantly to tumor progression and resistance in CCA. Therefore, we investigated the novel, first-in-class SFK ‘OFF’ inhibitor NXP900 in diverse preclinical CCA models, including those with acquired resistance. This study evaluated the therapeutic effects of NXP900 and detailed adaptive molecular responses to SFK inhibitor therapy. We also aimed to identify biomarkers predictive of drug sensitivity using integrated multiomic profiling and develop strategies to overcome resistance. NXP900 inhibited YAP activity through direct inhibition of tyrosine phosphorylation and indirect activation of the Hippo pathway via LATS. These effects were associated with decreased tumor cell viability in CCA cell lines and several in vivo models. Notably, IDH -mutant patient-derived xenograft CCA models were particularly sensitive to NXP900. NXP900 also synergized with gemcitabine/cisplatin chemotherapy, enhancing antitumor efficacy in both in vitro and in vivo models. Multiomic analyses combining transcriptomics, global proteomics, and phosphoproteomics identified molecular features associated with primary response and acquired resistance. IL13RA-AKT signaling was upregulated in resistant models; NXP900 sensitivity could be restored with AKT or IL13RA2 inhibition. Together, these findings demonstrate the therapeutic potential of NXP900 as a novel YAP inhibitor in CCA and support further investigation in a clinical trial. Graphical Abstract