Citations

Hypoplastic left heart syndrome (HLHS) is the most lethal congenital heart disease (CHD). The pathogenesis of HLHS is poorly understood, and due to the likely oligogenic complexity of the disease, definitive HLHS-causing genes have not yet been identified. Postulating impaired cardiomyocyte proliferation as a likely important contributing mechanism to HLHS pathogenesis, and we conducted a genome-wide siRNA screen to identify genes affecting proliferation of human iPSC-derived cardiomyocytes (hPSC-CMs). This yielded ribosomal protein (RP) genes as the most prominent class of effectors of CM proliferation. In parallel, whole genome sequencing and rare variant filtering of a cohort of 25 HLHS proband-parent trios with poor clinical outcome revealed enrichment of rare variants of RP genes. In addition, in a familial CHD case we identified a rare, predicted-damaging promoter variant affecting RPS15A that was shared between the HLHS proband and a distant relative with CHD. Functional testing with an integrated multi-model system approach reinforced the idea that RP genes are major regulators of cardiac growth and proliferation, thus potentially contributing to the hypoplastic phenotype observed in HLHS patients. Cardiac knockdown (KD) of RP genes with promoter or coding variants (RPS15A, RPS17, RPL26L1, RPL39, RPS15) reduced proliferation in generic hPSC-CMs and caused malformed hearts, heart-loss or even lethality in Drosophila. In zebrafish, diminished rps15a function caused reduced CM numbers, heart looping defects, or weakened contractility, while reduced rps17 or rpl39 function caused reduced ventricular size or systolic atrial dysfunction of the atrium, respectively. Importantly, genetic interactions between RPS15A and core cardiac transcription factors TBX5 in CMs, Drosocross, pannier and tinman in flies, and tbx5 and nkx2-7 (nkx2-5 paralog) in fish, support a specific role for RP genes in heart development. Furthermore, RPS15A KD-induced heart/CM proliferation defects were significantly attenuated by p53 KD in both hPSC-CMs and zebrafish, and by Hippo activation (YAP/yorkie overexpression) in developing fly hearts. Based on these findings, we conclude that RP genes play novel critical roles in cardiogenesis and constitute an emerging class of gene candidates likely involved in HLHS.

Abstract Description CD8 T cell programming creates a pool of naïve, effector, memory, or exhausted subsets, however the regulation of these trajectories is not expansively elucidated and has serious implications for cancer immunity and immune checkpoint inhibitor (ICI) therapy. We found a significant decrease of Dual Specificity Phosphatase 2 (DUSP2) in CX3CR1+ CD8s, a highly resilient subset, from ICI responders. Thus, we hypothesized that DUSP2 negatively regulates CD8 T cells in responses to ICI therapy. DUSP2 knockdown (KD) statistically improved CD8 cytotoxicity and expression of NKG7, a vital effector molecule. DUSP2 KD also increased SMARCA4 expression, a BRG/BRM-associated factor (BAF) complex ATPase, and increased open chromatin regions of BAF components. BAF complexes are chromatin remodelers implicated in CD8 differentiation pathways. In line with this, we found CD8s from DUSP2 conditional knockout (cKO) mice demonstrated a trend in defective memory generation. DUSP2 cKO CD8s also trended towards decreased PD-1 and increased CX3CR1 expression, demonstrating a more effector like phenotype. DUSP2 cKO mice did not show a significant difference in tumor protection in-vivo, presumably due to skewing of CD8 fates via BAF. Promisingly, DUSP2 KD increased ex-vivo cytotoxic functionality in about 50 percent of tested cancer patient PBMCs. Adjuvant BAF inhibition with DUSP2 KO versus KD in a specific CD8 subset may enhance responses further, providing a novel avenue for improving ICI efficacy. Funding Sources Supported by NCI 1F31CA287495-01 Topic Categories Immune Response Regulation: Molecular Mechanisms (IRM)

Abstract Description Cholangiocarcinoma (CCA) is an aggressive epithelial malignancy of the bile duct, with rising global incidence and poor prognosis. Current treatments achieve only 20-30% response rates in advanced cases, highlighting the need for novel therapeutic approaches. The tumor microenvironment (TME) has emerged as a critical focus for innovative therapies. Sulfatase 2 (SULF2) is a heparan sulfate (HS)-editing enzyme that alters HS chain affinity for growth factors and receptors, modulating heparan sulfate proteoglycans (HSPG) in cell signaling pathways. Specific sulfatases in HSPGs have been implicated as therapeutic targets in CCA. This study investigates the potential of anti-SULF2 antibodies to modulate immune cells within the TME using a C57BL6 syngeneic mouse model. Anti-SULF2-treated mice were compared to untreated controls, with tumors analyzed via CyTOF. Treatment resulted in reduced immunosuppressive cells and increased anti-tumor immune cells, suggesting that SULF2 inhibition shifts the TME toward an anti-tumorigenic state. These findings highlight SULF2 as a promising target for therapeutic intervention. Future studies will explore spatial transcriptomic and proteomics to elucidate the interplay between SULF2 expression in the TME makeup. We will also explore the molecular mechanisms of SULF2 suppression and its influence on cytokine signaling pathways within the TME. Funding Sources Supported by CTSA Grant Number TL1 TR002380 from the National Center for Advancing Translational Science (NCATS). Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Abstract Description Therapies targeting the PD-1/PD-L1 axis are among the leading treatments of cancer, but only a minority of patients benefit. Many therapies focus on preventing PD-L1 from binding to its receptor, PD-1, but do not address PD-L1’s ability to be recycled to the cell surface and any intrinsic functions it may possess. Our lab has developed an antibody (H1A) that binds to PD-L1 and prevents its association with a stabilizing protein, CMTM6, therefore targeting it for lysosomal degradation. Consequently, H1A limits any PD-L1 intrinsic function while also decreasing interactions with PD-1. Here, we use human-derived immune cells to test H1A’s effect on immune responses through flow cytometry, multiplex screening, and cytotoxicity assays. Additionally, we have developed a humanized PD-1/PD-L1 mouse model that allows us to test H1A’s effect on tumor growth inhibition in an immunocompetent host. Our results show that H1A specifically targets human myeloid cells, resulting in increased co-stimulation, antigen presentation, and cytokine secretion. H1A demonstrated enhanced T cell cytotoxicity in a whole PBMC culture. Finally, H1A resulted in greater tumor growth inhibition and survival in our in vivo tumor models. This work highlights the importance of targeting beyond PD-1/PD-L1 ligation and that myeloid cells are instrumental to enhancing the immune response against cancer. H1A is emerging as a new immunotherapy tool to target PD-L1 and CMTM6 in myeloid cells for treatment of cancers. Funding Sources NIH R01 92389022; NIH T32 AI170478; Mayo Clinic Graduate School of Biomedical Sciences Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Importance Total pancreatectomy (TP) is indicated for advanced pancreatic cancer or multifocal tumors. Furthermore, TP may be performed to avoid the risk of pancreatic fistula in selected patients to improve the perioperative risk profile. Objective To define reference values for TP based on a low-risk cohort treated at expert centers. Design, Setting, and Participants This multicenter study analyzed outcomes from patients undergoing primary TP for malignant or benign lesions from 25 international expert centers from January 2017 to November 2023. Low-risk patients undergoing TP (LR-TP) were without vascular resections or significant comorbidities. Exposures TP. Main Outcomes and Measures Twenty reference values were derived from the 75th or the 25th percentile of the median values of all centers. Outcomes of LR-TP were compared with a cohort of TP with vascular resection, TP due to high-risk pancreatic anastomosis, and the benchmark values for low-risk pancreatoduodenectomy. Results Of 994 patients, 333 (33.5%; median [IQR] age, 66 [58-72] years; 171 male [51.4%]) qualified as the LR-TP cohort. Reference values included blood loss (≤1000 mL), major complications (≤37%), 3-month postoperative mortality (<6%), and retrieved lymph nodes (≥29). Compared with TP with vascular resections, reference cutoffs were not met for major complications (51% vs LR-TP ≤37%) and 90-day mortality (11% vs LR-TP ≤6%). For TP due to high-risk anastomosis, failure to rescue rate (38% vs ≤6%) and 90-day mortality (11% vs LR-TP ≤6%) were not met. Compared with pancreatoduodenectomy, reference values for postoperative mortality were 3 times higher for LR-TP (≤2% vs ≤6%) and less for resected lymph nodes (≥16 vs ≥29). Conclusions and Relevance This case-control study provided global reference values for TP, indicating significantly higher postoperative morbidity and mortality compared with pancreatoduodenectomy. Perioperative morbidity of TP was especially increased in patients with vascular resections. These reference values can serve for quality control of pancreatic surgery.

Abstract Recurrent or refractory IDH-mutant (mt) gliomas represent a population with significant unmet clinical need. The Notch ligand delta-like 3 (DLL3) is a tumor-associated antigen that is highly and homogeneously expressed in IDH-mt gliomas but absent in normal brain tissue, making it an attractive therapeutic target. Tarlatamab is a half-life extended bispecific T-cell engager that targets DLL3 and CD3 to redirect cytotoxic T cells toward DLL3-expressing tumor cells. Given the specific expression of DLL3 in IDH-mt gliomas and promising activity of tarlatamab in other DLL3-positive tumors, this study investigates the safety, efficacy, and intracranial activity of tarlatamab in this patient population. TARGID is an open-label, phase II trial enrolling adult patients with histologically confirmed IDH1 or IDH2-mt astrocytoma or oligodendroglioma following up to two prior lines of systemic therapies. The study comprises two cohorts. Cohort 1 (n=10) includes patients with resectable disease who will receive up to three cycles of tarlatamab prior to surgery; postoperative continuation is permitted. The primary endpoint for this cohort is the change in CD8+ T-cell infiltration in tumor tissue and blood. Cohort 2 (n=34) includes patients with unresectable disease and uses a Simon’s optimal two-stage design (H0: P ≤ 0.1 versus H1: P ≥ 0.25). In the 1st stage, 13 patients will be accrued. If 2 or more responses are observed, 21 additional patients will be enrolled. Tarlatamab is administered intravenously at 10 mg every two weeks, following a 1 mg priming dose on Cycle 1 Day 1. The primary endpoint is objective response rate by RANO 2.0. Exploratory endpoints include DLL3 expression, circulating biomarkers, and immune correlatives. The trial is currently in activation, with first patient enrollment anticipated in Q3 2025. The study is supported by the provision of study drug from Amgen as an investigator-initiated trial.

Abstract BACKGROUND Post-operative prognostication in glioma patients remains a clinical challenge, particularly given the heterogeneity in tumor biology and patient outcomes. We evaluated whether image-derived features from post-operative imaging improve survival modeling beyond established clinicopathologic factors. METHODS We analyzed a cohort of 71 post-surgical glioma patients treated at Princess Margaret Cancer Centre with known clinicopathologic features including age, histological classification, IDH mutation status, MGMT methylation status, extent of resection, and performance status. A baseline Cox proportional hazards model was fit to clinical variables. Radiomic features were extracted using PyRadiomics from post-operative CT and MRI across three regions of interest: whole brain, tumor bed, and peritumoral ring. Features underwent stepwise unsupervised reduction (variance filtering, exclusion of volume-correlated features, and removal of remaining collinear features), followed by dimensionality reduction via principal component analysis. Combined clinical and imaging models were evaluated in the overall cohort and stratified by IDH mutation status. RESULTS In the overall cohort, the clinical model was highly prognostic (C-index 0.74, p ~ 3.2×10⁻⁶). Adding imaging features improved performance (C-index 0.79) but was not significant (p ~ 0.31). Subset analysis revealed differential effects by IDH status. In IDH-mutant gliomas (n=24), neither clinical nor combined models were significant. In IDH wild-type glioblastoma (n=47), the clinical model achieved C-index 0.75 (p=0.04). The addition of imaging features significantly improved model performance (C-index 0.83, p=0.03), with selected imaging components contributing independent prognostic value after adjustment for clinical variables. Post-hoc analysis of radiomic feature importance (random forest ranking) revealed that top contributing features were drawn from both CT and MRI modalities, with most sourced from the whole brain region. CONCLUSIONS In post-surgical patients with IDH wild-type glioblastoma, image-derived features from post-operative imaging can significantly enhance prognostic modeling beyond known clinicopathologic factors. These preliminary findings support the potential role of radiomic biomarkers in refining risk stratification for this patient subgroup.

The NCCN Guidelines for Prostate Cancer provide a framework on which to base decisions for patients with prostate cancer across the disease spectrum. The Guidelines sections included in this article focus on metastatic castration-sensitive prostate cancer (mCSPC), nonmetastatic castration-resistant prostate cancer (CRPC), and metastatic CRPC (mCRPC). For patients with mCSPC, disease characteristics, such as whether metastases arose synchronously or metachronously and the degree of metastatic burden, impact therapy decisions, including how much treatment intensification is appropriate and when prostate-directed and/or metastasis-directed therapy should be considered. In the mCRPC setting, androgen deprivation therapy is continued with the sequential or concurrent addition of certain androgen receptor pathway inhibitors, chemotherapies, immunotherapies, radiopharmaceuticals, and/or targeted therapies. The NCCN Prostate Cancer Panel emphasizes a shared decision-making approach in all disease settings based on patient preferences, prior treatment exposures, biomarkers, the extent and location of metastases, symptoms, and potential side effects.

Abstract Pancreatic adenocarcinoma remains one of the most lethal malignancies, primarily due to its robust resistance to genotoxic therapies, such as chemotherapy and radiotherapy. Understanding the mechanisms underlying this resistance is essential to improve clinical outcomes. In this study, we identified trimethylguanosine synthase 1 (TGS1), previously known for its role in RNA modification, as a critical mediator of homologous recombination (HR) repair that specifically contributes to resistance in pancreatic adenocarcinoma. TGS1 was significantly overexpressed in pancreatic adenocarcinoma tissues, correlating strongly with advanced disease stages, therapy resistance, and poor patient prognosis. Following DNA damage, ATM kinase phosphorylated TGS1 at serine residues S389 and S531, which mediated its direct interaction with BRCA1 and subsequent recruitment of BRCA1 to DNA damage sites. The phosphorylation-dependent interaction enhanced HR repair efficiency, enabling cancer cells to survive genotoxic stress. Depletion or pharmacologic inhibition of TGS1 induced HR deficiency and markedly enhanced sensitivity to DNA-damaging agents, particularly PARP inhibitors, in pancreatic adenocarcinoma cell lines in vitro and in both cell line– and patient-derived xenograft models in vivo. Collectively, these findings uncover an ATM–TGS1–BRCA1 signaling axis that promotes DNA repair and resistance to genotoxic therapies in pancreatic cancer, positioning TGS1 as a promising predictive biomarker and therapeutic target to enhance treatment efficacy. Significance: The ATM–TGS1–BRCA1 signaling axis is a critical regulator of DNA repair that can be targeted to overcome genotoxic therapy resistance, providing a promising therapeutic strategy that could transform pancreatic cancer treatment.

BACKGROUND: Obstructive sleep apnea (OSA) is a prevalent comorbidity strongly associated with cardiovascular diseases, particularly in patients with aortic dissection (AD). However, the long-term impact of severe OSA on survival and distal aortic remodeling after total arch replacement for acute type A aortic dissection (ATAAD) remains unclear. OBJECTIVES: This study aimed to elucidate the specific long-term prognostic impact of severe OSA in patients undergoing ATAAD repair. METHODS: A total of 86 prospectively collected patients who underwent acute type A aortic dissection repair at Beijing Anzhen Hospital between January 2018 and December 2018 were enrolled in the study. All these patients underwent total aortic arch replacement. All patients underwent sleep monitoring within 90 days postoperatively. The association between severe OSA and major adverse events (MAEs) was analyzed using a multivariable Cox proportional hazards model. Kaplan-Meier survival analysis was performed to assess long-term survival. RESULTS: Of these 86 patients, 22 (25.6%) exhibiting severe OSA and 64 (74.4%) not. Individuals with severe OSA had a notably higher rate of major adverse events (MAEs) compared to those without severe OSA (27.3% vs. 7.8%, P =0.047) and a significantly lower long-term survival rate (81.8% vs. 97.4%, P =0.003). After adjusting for potential confounding variables, severe OSA remained an independent predictor of MAEs (HR=3.7, 95% CI: 1.1–12.4, P =0.032). Imaging follow-ups indicated that patients with severe OSA experienced significantly higher stent-graft distal aortic expansion rates (1.8 mm/year vs. 0.4 mm/year, P =0.030), abdominal aortic expansion rates (2.2 mm/year vs. 0.7 mm/year, P <0.001), and false lumen expansion rates in the descending aorta (2.5 mm/year vs. 0.8 mm/year, P =0.003). Moreover, partial thrombosis of the false lumen was more frequently observed in patients with severe OSA (40.9% vs. 14.1%, P =0.028). Conversely, complete false lumen thrombosis (64.1% vs. 45.5%, P =0.028) and false lumen patency (21.9% vs. 13.6%, P =0.028) were more commonly observed in patients without severe OSA. CONCLUSIONS: Severe OSA is associated with an elevated risk of MAEs and is implicated in abnormal distal aortic expansion and false lumen thrombosis among patients undergoing ATAAD repair. These results highlight the importance role of identifying and managing severe OSA in the long-term postoperative care of patients with ATAAD.