Cancer Letters

Recurrence remains a significant clinical challenge for triple-negative breast cancer patients and radiotherapy (RT) is a key therapeutic tool that significantly reduces the risk of relapse. Despite this, patients with chronic lymphopenia and a high neutrophil:lymphocyte ratio (NLR) experience recurrence at significantly higher rates than those whose hematological biomarkers return to baseline post-RT, and there are currently no treatments to prevent this relapse. Here, we utilized in vivo mouse models of lymphocyte-deficiency to identify the mechanism behind systemic immune status and recurrence. Using a model of RT-induced circulating tumor cell (CTC) colonization, we found that neutrophils are sustained in the irradiated, lymphocyte-deficient mammary tissue up to 10 days post-RT. Persistent neutrophil accumulation was accompanied by excessive vascular remodeling and tumor cell colonization of the mammary tissue, both of which were abated upon systemic neutrophil depletion. Neutrophils in the colonization-permissive microenvironment exhibited a state of pathological activation consistent with a polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) phenotype that was not seen in systemic compartments, highlighting a microenvironment-induced phenotype shift. This phenotype was recapitulated in vitro when naive neutrophils were exposed to the secretome of RT-induced senescent endothelial cells (ECs). We found that these activated neutrophils then regulated the dysfunction of irradiated ECs in a canonical NF-kB-dependent manner, increasing their barrier permeability and activating downstream inflammatory signals. Our findings not only establish neutrophils as a critical component of tumor cell colonization in lymphocyte-deficient subjects but also uncover a positive feedback loop between neutrophils and irradiated vasculature that leads to aberrant tissue remodeling and ultimately tumor cell colonization. This work deepens our understanding of how systemic factors influence treatment-damaged microenvironments, which could ultimately lead to identification of molecular targets for prevention of RT failure.

Xp11.2 translocation RCC [Xp11.2 tRCC]) is an underdiagnosed and aggressive subtype of RCC with few specific or targeted therapies. The transmembrane glycoprotein CD44 is an emerging target in many advanced malignancies, and with its ligand OPN (SPP1), is a crucial driver of cancer progression, stemness, metastasis, and immune suppression. Here we show that common TFE3-fusions [ including SFPQ-TFE3, PRCC-TFE3, ASPSCR1-TFE3, and NONO-TFE3] are associated with upregulated expression of CD44 and SPP1, as observed in multiple human and murine bulk transcriptomic studies and a murine tRCC snRNA-Seq dataset. CD44 and/or SPP1 protein expression were also upregulated in murine models of transgenic tRCC kidneys and urine specimens, patient-derived cell lines and human tRCC cases, by immunoblotting and/or IHC. Transient deletion of CD44 was associated with profound and specific suppression of tRCC cell line growth, with decreased mTOR signaling. These data suggest that CD44 and/or SPP1 may potentially drive tumorigenesis in tRCC.

Metabolic reprogramming is a hallmark of cancer cells, and stem-like populations often upregulate aldehyde dehydrogenases (ALDHs). Functional studies have established essential roles for individual ALDH isoforms in tumor initiation, progression, and metastasis; however, the mechanisms by which these enzymes promote malignancy remain poorly understood. Here we show that aldehyde dehydrogenase 1B1 (ALDH1B1), a mitochondrial enzyme highly expressed in colorectal cancer (CRC) and pancreatic ductal adenocarcinoma (PDAC), generates {gamma}-butyrobetaine (GBB) and {gamma}-aminobutyric acid (GABA) in CRC cells. The biosynthesis of both aminocarboxylic acids has been attributed to the cytosolic enzyme ALDH9A1, and we demonstrate that mitochondrial GBB and GABA are functionally distinct from the cytosolic pools of these metabolites. We further demonstrate that mitochondrial GBB can function as an antiport substrate of carnitine-acylcarnitine translocase (CACT), the transporter that mediates fatty acid uptake into the mitochondrial inner matrix. This activity complements the role of cytosolic GBB as the biosynthetic precursor to carnitine. Accordingly, ALDH1B1 can markedly enhance mitochondrial fatty acid oxidation (FAO), a catabolic process that has been linked to CRC and PDAC stemness, progression, and metastasis. Our findings reveal an unexpected role for ALDH1B1 in carnitine metabolism, GABA biosynthesis, and FAO and illustrate how the compartmental reprogramming of metabolic pathways can promote tumor growth.

Colorectal cancer (CRC) exhibits substantial intratumoral heterogeneity, with differences in oncogenic driver mutations and apoptotic competence contributing to therapeutic resistance. Here, we investigated whether combined celecoxib and NDGA treatment (C+N) induces redox-mediated cell death via the p62/KEAP1 axis, offering a therapeutic approach that can overcome genetic diversity in CRC. We used two genetically distinct CRC cell lines, HCT116 and HT29, harbouring KRAS and BRAF mutations respectively, with differing p53 status, as models of tumor heterogeneity. C+N exhibited profound cytotoxicity in both cell lines, independent of COX-2/5-LOX expression and apoptotic competence. Additionally, C+N induced marked oxidative stress with mitochondrial ROS, lipid peroxidation, and labile ferrous iron accumulation, visualized as distinct JC-1 green mitochondrial puncta and FerroOrange red iron puncta in both cell lines. The antioxidant NAC reversed C+N-induced death, but inhibitors of apoptosis, autophagy, necroptosis, or ferroptosis did not, indicating a mechanism distinct from these pathways. Mechanistically, the combination induced p62 Ser349 phosphorylation, promoting KEAP1 degradation and NRF2 stabilization independently of ULK1-mediated autophagy; however, NRF2 stabilization was uncoupled from HO-1 induction. Our work reveals that C+N induces a ULK1/autophagy-independent, redox-mediated cell death mechanism that circumvents apoptotic competence, highlighting redox disruption as a genotype-independent therapeutic strategy to overcome CRC heterogeneity.

Cisplatin remains as standard chemotherapy for patients with HNSCC, but rapid development of drug resistance has limited patient benefit. The p53 tumor suppressor plays a central role in the cellular response to DNA damage in cancer, triggering apoptosis to prevent propagation of damaged cells in tumor development. TP53 gene mutations occur in 65-86% of HNSCC. Small molecule PG3 induces the integrated stress response (ISR), leading to apoptosis via the HRI-eIF2-ATF4-PUMA axis. We hypothesized that a combination of PG3 plus cisplatin could increase apoptosis in TP53-mutated HNSCC cells through enhanced induction of the ISR and ATF4. PG3 synergized with cisplatin to inhibit cell viability, leading to potent apoptosis in TP53-deficient cells. The effect was regulated through the HRI-ATF4-NOXA pathway. Furthermore, we identified that cisplatin activates HRI and leads to the degradation of CReP (constitutive repressor of eIF2 phosphorylation) via E3 ligase {beta}-TrCP, contributing to the induction of the ISR. We noted decreased ATF4 levels after treatment with cisplatin, CPT, or PG3 and cisplatin. Thus, combined therapy of PG3 plus cisplatin likely results in adaptation and acquired resistance via degradation of ATF4. We targeted the degradation mechanism of ATF4 by inhibiting {beta}-TrCP1, CK1{delta}, or CK2, respectively. Each approach successfully blocked ATF4 degradation induced by cisplatin or PG3 plus cisplatin and enhanced apoptosis. Our results provide a rational strategy for triple treatments, involving an ISR inducer, a DNA damaging drug, and a {beta}-TrCP inhibitor/CK1{delta} inhibitor/CK2 inhibitor, to achieve potent and prolonged anti-tumor effects and overcome chemoresistance in HNSCC.

Acute radiation syndrome remains a major consequence of high-dose ionizing radiation exposure, and effective pharmacological countermeasures are limited. Nitro-fatty acids possess anti-inflammatory and cytoprotective properties, suggesting potential effectiveness in radiation injury. Here, we investigated the radioprotective effects of 10-nitro-oleic acid (10-NO2OA) in mouse models of total body irradiation (TBI). C57BL/6 mice were exposed to either sublethal (4 Gy) or LD50-level (7.5 Gy) gamma irradiation and treated with 10-NO2OA according to pre-irradiation, post-irradiation, or combined treatment regimens. Survival, hematological responses, bone marrow cells (BMCs)/colony-forming units (CFU), plasma granulocyte colony-stimulating factor (G-CSF), NRF2-responsive signaling, and intestinal responses were evaluated. Administration of 10-NO2OA before and after irradiation significantly improved 30-day survival following 7.5 Gy TBI (57% vs. 20% in vehicle-treated controls). In contrast, post-irradiation treatment alone was ineffective, whereas pre-irradiation treatment alone produced a non-significant trend toward improved survival. The protective effect was absent in BALB/c mice, indicating strain dependence. Although 10-NO2OA did not prevent long-term radiation-induced cytopenia, it increased neutrophil and platelet counts, elevated plasma G-CSF levels shortly after irradiation, and transiently enhanced BMC counts. In irradiated BMCs, 10-NO2OA activated NRF2-responsive gene expression in vitro and in vivo. Exploratory intestinal analyses revealed improved macroscopic appearance and partial restoration of irradiation-suppressed cytokine and growth factor production. In conclusion, 10-NO2OA improves survival following LD50-level gamma irradiation and is associated with modulation of hematopoietic, cytoprotective, and intestinal responses. These findings identify 10-NO2OA as a promising candidate radioprotective agent and support a multifactorial mechanism of action.

Abstract Metabolic and epigenetic reprogramming drives development of platinum resistance and disease recurrence in high-grade serous ovarian cancer (HGSC), a major clinical challenge in the field. S-adenosylmethionine (SAM) is the universal methyl group donor, synthesized by methionine adenosyltransferase 2A (MAT2A) from methionine. Prior studies have linked altered SAM-dependent DNA methylation to acquired platinum resistance in HGSC, connecting metabolism and epigenetic regulation. However, how MAT2A-driven SAM synthesis coordinates the metabolic-epigenetic remodeling axis to affect platinum sensitivity remains unclear. Here, we report that MAT2A-driven SAM synthesis is required for platinum-induced alterations in DNA methylation and the enrichment of ovarian cancer stem cells (OCSCs). We found that MAT2A upregulation correlated with poor progression-free survival in OC patients, and both pharmacological inhibition and genetic knockdown of MAT2A increased sensitivity to cisplatin. To investigate the underlying epigenetic mechanism, we profiled genome-wide changes in DNA methylation using OVCAR3 treated with cisplatin (15M, 16hr) and/or MAT2A siRNA (48hr), which showed that MAT2A knockdown reversed platinum-induced DNA methylation dynamics. Subsequent analysis revealed enrichment of pathways associated with platinum resistance, DNA repair, and stemness. Mechanistically, inhibiting MAT2A abrogated both the platinum-induced hypermethylation at promoter regions and the SAMTOR-mTOR-S6K-FANCD2 signaling axis, resulting in accumulated R-loops, attenuated DNA repair activation in response to platinum, and enhanced platinum-induced DNA damage and cell death. Using a functional DNA damage reporter assay, we directly showed that MAT2A knockdown reduced DNA repair through homologous recombination (HR) and non-homologous end joining (NHEJ) pathways. By detecting key DNA damage response kinases governing HR and NHEJ signaling, we further demonstrated that MAT2A inhibition abrogated DNA repair activation in response to platinum. Furthermore, single-sample Gene Set Enrichment Analysis of paired primary and recurrent tumors from HGSC patients revealed an association between MAT2A expression and increased OCSC features in recurrent tumors. In vitro, MAT2A inhibition prevented cisplatin-induced enrichment of OCSCs, reduced stemness markers, and inhibited spheroid-forming ability, all of which were rescued by SAM supplementation. Together, our study reveals a previously unrecognized mechanism linking metabolism to epigenetic regulation through platinum-induced remodeling and establishes the MAT2A-SAM axis as a promising therapeutic target to enhance platinum sensitivity by abrogating DNA damage response and OCSC enrichment and ultimately reduce OCSC-driven disease recurrence in HGSC.

Purpose: There is an unmet need in the treatment of triple-negative breast cancer (TNBC), as recurrence rates remain high; thus, novel treatment strategies are warranted to improve outcomes for patients. Smac mimetics (SMs) are small molecules that inhibit the inhibitors of apoptosis. In this study, we investigated the properties of the SM Xevinapant (AT406) as a radiosensitizer in TNBC. Methods: TNBC cell lines were treated with Xevinapant (AT406) in the presence or absence of ionizing RT and cell viability and apoptosis measured in vitro. Clonogenic assays were performed to confirm radiosensitization. We also assessed xevinapant radiosensitization in the presence of the Tumor Necrosis Factor (TNF) cytokine, which has been shown to enhance SM-induced apoptosis. Radiosensitization mechanisms were further validated by western blotting, flow cytometry and cell cycle analysis. Results: We show that Xevinapant increased cell death in a panel of irradiated TNBC cell lines. In clonogenic assays, Xevinapant sensitized MDA-MB-231 cells to RT-induced cell death, and this was significantly enhanced in the presence of TNF, with a dose-enhancing factor (DEF) of 1.57. We also show that Xevinapant radiosensitization is mediated by TNF-dependent apoptosis. Conclusions: Xevinapant is a radiosensitizer that enhances RT-induced cell death in TNBC cells, and TNF is central to this process through activation of apoptosis. These results are promising for combining RT with Xevinapant to improve local control in TNBC.

Adoptive T-cell therapy (ACT) has demonstrated marked clinical benefit in hematological malignancies but has limited efficacy against solid tumors. Cancer vaccines can improve ACT, but the mechanisms underlying this combination are poorly understood. Here, we combined ACT with chimpanzee adenovirus ChAdOx1 (ChAd) and modified vaccinia Ankara (MVA) encoding tumor antigens. Whereas PD1 blockade failed to improve ACT, the combination with ChAd/MVA vaccination drove durable regression of established tumors, correlating with expansion of tumor-reactive T cells in lymphoid organs and increased tumor infiltration by T cells. Mechanistically, ChAd priming induced CXCR3 ligands (CXCL10 and CXCL9) in the vaccine-draining lymph node, thereby recruiting transferred T cells to this node independently of cognate antigen. CXCR3 expression on the transferred T cells, but not on host cells, was required for the anti-tumor effect of the combination therapy and favored T-cell accumulation in the vaccine-draining lymph node and the tumor. These findings identify CXCR3 on the transferred T cells as a determinant of ACT plus vaccination synergy and provide a rationale for combining viral-vector vaccines with TCR-T therapies, and for selecting or engineering T cells to retain CXCR3 expression.

Background: The organization of pancreatic cancer care may be associated with survival. Using health administrative claims data, we reconstructed the pathway from diagnosis to first-line therapy and examined associations of multidisciplinary team review and treatment at specialized centers with overall survival. Methods: Longitudinal historical cohort study using anonymized health administrative claims data from six Czech health insurance funds, covering approximately 17% of patients diagnosed with pancreatic cancer nationally between 2018 and 2020. Adults with an incident ICD-10 C25 record confirmed by imaging and histopathology were followed from the index date (the date of the first qualifying imaging or histopathological examination) until death, censoring, or 31 December 2021. Overall survival was analyzed using Kaplan-Meier methods and Cox regression adjusted for age and first-line therapy type. Results: Of 1,255 patients, 920 (73.3%) received first-line therapy and 266 (21.2%) died untreated. Among treated patients, 436 (47.4%) underwent multidisciplinary team review, 335 (36.4%) underwent surgery, and 667 (72.5%) were treated at a complex oncological center. Surgery was associated with longer overall survival than chemotherapy (age-adjusted hazard ratio [HR] 0.32, P < 0.001). Treatment at a complex oncological center was associated with longer overall survival (adjusted HR 0.77, 95% confidence interval [CI] 0.64-0.92, P = 0.004; crude median 532 versus 394 days). Multidisciplinary team review was not significantly associated with overall survival (adjusted HR 0.86, 95% CI 0.73-1.01, P = 0.073). Conclusions: Treatment at a complex oncological center was associated with longer survival, while fewer than half of patients had a recorded multidisciplinary team review. How care is organized, not only which therapy is delivered, is associated with outcome. The observational design and absence of key clinical covariates limit causal interpretation.

The modulation of iron metabolism is increasingly explored as a therapeutic strategy in cancer, particularly through the induction of ferroptosis. Given the central role of ferritin as a major intracellular iron buffer, targeting ferritin represents an attractive strategy to disrupt iron homeostasis; however, the lack of pharmacological approaches capable of selectively targeting ferritin currently limits the therapeutic exploitation of this vulnerability. MMRi62, initially developed to target the MDM2-MDM4 axis, has been proposed to induce ferroptosis via ferritin degradation. Here, we revisited this hypothesis in the context of medulloblastoma (MB). Contrary to this proposed mechanism, we found that MMRi62 does not trigger ferroptosis but instead induces robust apoptotic cell death. This effect is observed in both p53-mutant DAOY and p53 wild-type HD-MB03 cells, as well as in c-Myc/OTX2-driven medulloblastoma-like tumours genetically induced in brain organoids. Although ferritin degradation occurs upon treatment, genetic dissection demonstrates that neither ferritin itself nor ferritinophagy are required for MMRi62-induced cytotoxicity. Together, these findings rule out ferritin-dependent mechanisms as primary drivers of cytotoxicity. Instead, we uncovered that MMi62 induces a profound rewiring of iron metabolism consistent with a canonical iron starvation response, accompanied by a marked reduction in intracellular iron levels. Consistently, the UV-visible spectroscopic data were in agreement with the proposed iron-chelating properties of MMRi62. Taken together, our findings identify iron depletion-driven apoptosis, rather than ferroptosis, independently of ferritin degradation, as the primary mechanism of MMRi62 cytotoxicity in MB, refining its mode of action and highlighting iron homeostasis as a therapeutic vulnerability.

Approximately 10% of bladder, upper urinary tract, and endometrial cancers harbor deleterious somatic alterations in nucleotide excision repair (NER) pathway genes. Although platinum-based chemotherapy is the standard treatment for NER-deficient tumors, its utility is limited by nephrotoxicity, motivating alternative strategies that avoid direct DNA targeting. Here, we employed a genome-wide CRISPR-Cas9 screen to identify synthetic lethal vulnerabilities in NER-deficient cancer cells. An ERCC4-null RT112/84 bladder cancer cell line was generated and validated by Sanger sequencing and Western blotting, and functional NER deficiency was confirmed using a host cell reactivation assay. Parallel screens in ERCC4-deficient and isogenic wild-type cells. nominated SLC25A28 as the top-ranked synthetic lethal candidate in ERCC4-deficient cells, an interaction further supported by DepMap dependency. Clonogenic assays confirmed that loss of SLC25A28 selectively impaired cell viability in cells deficient for ERCC2, ERCC3, ERCC4, or ERCC5 and inducible knockout selectively suppressed ERCC4-deficient xenograft growth in-vivo. Mechanistically, RNA sequencing followed by gene set enrichment analysis revealed enrichment of oxidative stress-related pathways, including cellular responses to reactive oxygen species (ROS) and DNA damage signatures, upon SLC25A28 loss. These transcriptional changes are consistent with increased oxidative stress and DNA damage, placing heightened demand on NER-mediated repair. Direct measurement confirmed increased intracellular ROS. Collectively, our nominates SLC25A28 as a previously unrecognized synthetic lethal vulnerability in NER-deficient cancers and implicate mitochondrial iron homeostasis as a candidate metabolic dependency that may be targeted independently of platinum-based chemotherapy.

Metastatic dissemination remains the principal cause of mortality in lung adenocarcinoma. To identify metabolic vulnerabilities associated with metastasis, we used cell lines with distinct metastatic abilities derived from the KrasG12D;p53KO mouse model. Building on evidence of mitochondrial dysfunction in metastasis-derived cells, we performed an in vivo screen of a focused metabolic drug library using a multiplexed DNA-barcoding platform. This approach identified artesunate as a selective inhibitor of metastatic seeding, which was validated in vivo to reduce metastatic burden while leaving primary tumor growth unaffected. Mechanistically, artesunate induced oxidative stress, characterized by reactive oxygen species and lipid peroxidation. Transcriptomic and mechanistic profiling revealed altered redox homeostasis in metastasis-derived cells. Inhibition of glutathione synthesis specifically sensitized these cells to artesunate, resulting in extensive cell death, whereas primary tumor-derived cells remained resistant. These findings identify glutathione-dependent redox homeostasis as a metabolic vulnerability in metastatic cells that can be specifically targeted using artesunate.

Germ cell tumors (GCTs) are highly sensitized to cell death in response to DNA damaging agents, a property that underlies the success of current chemotherapeutic regimens. To address the molecular basis for this, known as apoptotic priming, we evaluated how different BCL2 family members modulate the heightened sensitivity of GCTs to therapy. Our analysis of human GCTs finds consistently high expression of the pro-survival factors MCL1 and BCL2L1 (BCLX) in a cohort of primary tumors and in their embryonic precursor cells, frequently accompanied by copy number gains of these loci and reciprocal losses of their pro-apoptotic interaction partners and inhibitors, PMAIP1 (NOXA) and BAD. We find that co-inhibition of MCL1 and BCLX using selective BH3 mimetics results in a potent synthetic lethality in multiple GCT embryonal carcinoma cell lines. When these cell lines were cultured with the DNA damaging agents cisplatin or etoposide, inhibition of MCL1 or BCLX potentiated their apoptotic effect in undifferentiated embryonal carcinoma cell lines, but not in retinoic acid-differentiated cells. The inhibition of MCL1 also heightened cisplatin sensitivity in p53-deficient or -mutant cell lines, which is associated with resistance to therapy. Employing an in ovo human xenograft model, we validate that the combination of cisplatin and MCL1 inhibition enhanced the therapeutic response by eliminating tumor cells. Our findings identify MCL1 and BCLX as critical factors to maintain GCT viability and as putative therapeutic targets to further augment GCT responsiveness to DNA damaging agents.

The immunosuppressive tumor microenvironment (TME) poses formidable challenges for cancer immunotherapies. Among the complex TME landscape, the cytokine TGF-{beta}1 is an attractive soluble target for reinvigoration of anti-tumor immunity due to its pivotal function in immune cell suppression, extracellular matrix remodeling, and epithelial-to-mesenchymal transition (EMT) promotion, while immune checkpoint receptors exemplified by PD-1 and CD24 are promising surface targets. Though adaptive immune checkpoint inhibition is well established in clinical practice, TGF-{beta} blockade or innate immune checkpoint blockade is yet to be harnessed for tumor treatment. Here, leveraging CD24 overexpression on multiple tumor tissues and its unique recycling kinetics, we designed an innate Immune Checkpoint TArgeting Chimera (ICTAC) G01, a bifunctional CD24 antibody-TGF-{beta}1 receptor fusion protein that disrupts TGF-{beta}1 signaling by TGF-{beta}1 degradation instead of simple blockade and simultaneously inhibits the "don't eat me" CD24 signaling. We demonstrated that G01 effectively suppressed TGF-{beta}1-Smad signaling, reversed the EMT, and attenuated fibrotic collagen deposition. Additionally, it antagonized CD24 signaling to unleash robust antibody-dependent effector activity, further reprogramming the immunologically cold TME toward inflammatory phenotype. By selectively targeting malignant cells while sparing CD24-expressing B cells, G01 demonstrated a favorable safety profile. Notably, in patient-derived tumor fragments (PDTFs), G01 also inflamed the TME, underscoring its translational potential. Together, these results establish ICTAC as an effective strategy for tumor-specific receptor-mediated extracellular protein depletion, which supports its application for reversing TGF-{beta}1; and innate immune checkpoint-mediated tumor immunosuppression by concurrent targeting of both surface and soluble tumor-promoting factors.

BackgroundCancer-associated fibroblasts (CAF) are major regulators of the tumor microenvironment (TME), yet the pathways governing CAF function remain incompletely understood. Type 2 deiodinase (DIO2, D2), which converts thyroxine (T4) to the active thyroid hormone triiodothyronine (T3), has not been systematically investigated in CAF across different solid tumors. MethodsWe analyzed DIO2 expression using single-cell RNA sequencing (scRNA-seq) from primary thyroid tumors, a large integrated scRNASeq thyroid cancer atlas, and publicly available scRNA-seq datasets representing six additional solid tumor types. Bulk RNA sequencing data from the Oncology Research Information Exchange Network (ORIEN) database were used to examine correlations among DIO2, CAF subtype markers, and overall survival (OS). A genetically engineered TPO-CreERT2/BrafV600E/Trp53-deficient (TBP) mouse model was evaluated for CAF-specific Dio2 expression and pharmacologic inhibition of D2 activity. TBP mice were crossed with Dio2-/- (Dio2 KO) mice to investigate the role of Dio2 in cancer development and progression. ResultsDIO2 expression was highly restricted to CAF and was largely absent from epithelial-derived cancer, immune, and endothelial cells. Across thyroid cancer and six additional malignancies, DIO2 was consistently detected in CAF, demonstrating that CAF-specific DIO2 expression is a conserved feature of multiple tumor types. Within thyroid cancer, DIO2 was enriched in myofibroblastic CAF (myCAF) compared with inflammatory CAF (iCAF), and bulk transcriptomic analyses demonstrated stronger correlations between DIO2 expression and canonical myCAF markers than iCAF markers across numerous cancers. Elevated DIO2 expression was associated with worse OS in pancreatic and bladder cancers, paralleling the adverse prognostic impact of increased myCAF abundance. In contrast, thyroid cancer demonstrated an inverse association attributable to loss of epithelial DIO2 expression during tumor dedifferentiation. The TBP mouse model recapitulated human disease, with Dio2 expression restricted to CAF, robust stromal fibrosis, and measurable D2 enzymatic activity that was suppressed by cefuroxime and lenvatinib. Genetic loss of Dio2 in the TME resulted in significantly reduced tumor growth. Conclusions DIO2 is a conserved marker of CAF, and myCAF, across multiple solid tumors and is associated with adverse clinical outcomes in some cancers. The TBP mouse provides a robust preclinical model to define the mechanistic role of DIO2 in CAF biology and to evaluate DIO2-directed therapeutic strategies targeting the tumor microenvironment.

Glioblastoma (GBM) exhibits extensive loss of circular RNAs (circRNAs), yet the mechanisms driving this depletion and its functional consequences remain unclear. Here, we identify the splicing co-factor SON as a previously unrecognized suppressor of circRNA biogenesis in GBM. CircRNA sequencing revealed widespread increases in circRNA abundance following SON knockdown. Conversely, elevated SON expression in GBM, with further increases in radiation-resistant models, was associated with widespread circRNA loss, including reduced expression of circUSP1 and circSUCO. SON knockdown increased circRNA abundance and attenuated activation of the dsRNA-responsive kinase PKR and downstream NF{kappa}B signaling, whereas radiation-resistant GBM cells exhibited enhanced PKR/NF{kappa}B activation that was attenuated by SON depletion. Importantly, overexpression of the SON-suppressed circRNAs circUSP1 and circSUCO reduced PKR activation and selectively decreased clonogenic survival following irradiation in radiation-resistant GBM cells, with little effect on parental cells. Together, these findings identify a previously unrecognized SON/circRNA/PKR regulatory pathway linking RNA processing to acquired radiation resistance in GBM and highlight specific PKR-inhibitory circRNAs as potential therapeutic tools for resensitizing radiation-resistant GBM to radiotherapy.

Background: Cancer patients face a significantly elevated risk of severe COVID-19 outcomes. Although vaccination is a cornerstone of prevention, data on vaccination coverage and association with survival among Russian cancer patients remain scarce. We assessed COVID-19 vaccination coverage and its association with overall survival in a population-based cohort of cancer patients in Northwest Russia. Methods: This retrospective registry-based cohort study integrated data from the Population-Based Cancer Registry (PBCR) of the Arkhangelsk Region and the Nenets Autonomous Okrug, regional vaccination records, and an artificial intelligence (AI)-based analysis of chest computed tomography (CT) scans. The cohort consisted of 1,144 cancer patients who underwent CT between August 2020 and April 2021. Vaccination status was ascertained via data linkage. Overall survival (OS) was compared between vaccinated and unvaccinated patients using Kaplan-Meier analysis and multivariable Cox proportional hazards regression, adjusted for demographic, clinical, and AI-derived CT biomarkers. To mitigate immortal time bias, the primary analysis used a landmark approach restricted to patients alive on March1, 2021 (N=1,136). A sensitivity analysis used a November1, 2021 landmark (N=894). Vaccination status was defined as receipt of at least one dose before the landmark date. Results: Only 6.6% (n=76) of patients received at least one dose of a COVID-19 vaccine (Sputnik V or Sputnik Light). Vaccinated patients were more likely to have earlier-stage cancer and were less likely to be receiving active treatment. In the primary landmark analysis, vaccination was associated with a significantly higher 3-year OS (80.3% vs. 45.7%, p<0.001). In multivariable analysis, vaccination was independently associated with a 60% lower hazard of all-cause mortality (adjusted HR 0.40, 95% CI 0.25-0.64). AI-detected COVID-19 pneumonia on baseline CT was also an independent predictor of poorer survival (adjusted HR 1.32, 95% CI 1.09-1.59). In the sensitivity analysis (November1, 2021 landmark), the adjusted HR for vaccination was 0.56 (95% CI 0.34-0.92), showing a consistent but attenuated association. Conclusion: This study reveals critically low COVID-19 vaccination coverage among cancer patients in Northwest Russia. Nevertheless, vaccination was strongly associated with a substantial survival benefit, underscoring its importance as a potentially lifesaving intervention for this vulnerable population.

Background: Stroke risk is increased in cancer patients, but variations by stroke type, cancer characteristics, and treatment timing remain incompletely characterized. We investigated stroke incidence after cancer diagnosis and temporal patterns of ischemic stroke around treatments. Methods: We conducted a retrospective multicenter cohort study using linked cancer registry and administrative data from 68 cancer hospitals in Osaka, Japan. Patients diagnosed between 2019 and 2022 were followed for up to 1 year. In diagnosis-based analyses, standardized incidence ratios (SIRs) compared stroke incidence with the general population. In treatment-based analyses, ischemic stroke incidence rates and adjusted incidence rate ratios (IRRs) were estimated from 14 days before through 365 days after cancer treatments (surgery, chemotherapy, or radiotherapy). Results: Among 190,471 patients, 1660 strokes occurred: 1296 (78.0%) ischemic strokes, 315 (19.0%) intracerebral hemorrhages, and 49 (3.0%) subarachnoid hemorrhages. In diagnosis-based analyses, the overall stroke SIR was 2.13 (95% CI, 2.03?2.24), with a 1.01% 1-year cumulative incidence. SIRs were 2.37 (95% CI, 2.24?2.50), 1.72 (95% CI, 1.53?1.92), and 1.22 (95% CI, 0.91?1.62) for ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage, respectively. SIRs peaked immediately after diagnosis and declined thereafter. Excess risk persisted through 180 days for ischemic stroke, 30 days for intracerebral hemorrhage, and 7 days for subarachnoid hemorrhage. In treatment-based analyses, ischemic stroke incidence increased transiently around treatments. After surgery, the adjusted IRR peaked during days 0?7 (12.27 [95% CI, 8.50?17.71]) and remained elevated through days 31?90 versus days 181?365. A postoperative increase was observed even in early-stage disease. For chemotherapy, incidence was relatively high before treatment initiation. Conclusions: Stroke risk after cancer diagnosis varied by stroke type, cancer characteristics, and time since diagnosis. Ischemic stroke incidence increased transiently around cancer treatment, including an early postoperative increase in patients with early-stage disease. These findings identify periods and patient groups that may warrant heightened clinical vigilance.

Purpose Tarlatamab, a bispecific T-cell engager, has generated favorable response and survival outcomes in relapsed small cell lung cancer (SCLC). Factors influencing tarlatamab-associated treatment outcomes and toxicity have yet to be established. We performed a multivariate analysis to identify biomarkers associated with cytokine release syndrome (CRS) and immune effector cell associated neurotoxicity syndrome (ICANS) and integrated these variables into a novel risk stratification tool to identify patients at high risk of clinically significant toxicity. Patients and Methods Logistic and ordinal regression analyses evaluated the predictive value of variables contributing to the presence and severity, respectively, of CRS and ICANS in 115 patients with ES-SCLC receiving tarlatamab. Selected variables were then tuned using 5-fold cross-validation and incorporated into novel elastic net-based prediction models. Results Rates of observed CRS, ICANS, and dysgeusia were 46%, 28%, and 47%, respectively. ORR (overall response rate) and DCR (disease control rate) were 44% and 58.2%, while 6-month PFS (progression free survival) and OS (overall survival) rates were 30.4% and 54.9%, respectively. Excluding patients on tarlatamab <30 days, presence of dysgeusia was associated with a lower rate of disease progression (HR 0.44, p=0.00691) and death (HR 0.34, p=0.0145). The presence of, increased size and number of extracranial metastases as well as elevated baseline LDH were significantly associated with increased likelihood of CRS. Increased ECOG performance status, increased volume of brain metastases, development of CRS, and elevated baseline LDH were all associated with increased risk of developing ICANS. Our cross-validated risk model successfully predicted CRS grade [&ge;]2 and ICANS events with 90.9% and 75% sensitivity, respectively. Conclusions This exploratory analysis identified several predictive biomarkers of toxicity that successfully stratified low and high-risk populations as part of an internally validated novel risk scoring tool.