Frederick National Laboratory for Cancer Research

There are no cures for neurodegenerative diseases. The biggest hurdle to treating these disorders is that their clinical manifestation is rooted in multiple physiological processes. Therefore, efficacious pharmaceutical options will likely require two or more agents with different mechanisms of action. However, drug combinations have significant drawbacks, including overlapping toxicities and unique pharmacokinetic properties, particularly the rate and extent of central nervous system (CNS) penetration. A single agent with multiple mechanisms of action could overcome these drawbacks. We have recently discovered first-in-class novel single agents (compounds 1 and 2) that mildly inhibit clinically important kinases and subtly favor microtubule stability at concentrations that show no evidence of neuronal toxicity in primary neurons, while maintaining their ability to penetrate the CNS in vivo. It is important to note that the effects of these analogs are mild and are predicated on avoiding neurotoxicity. These multitargeting single agents provide a new structural modality with the potential to influence treatments for Parkinson's and Alzheimer's disease and serve as lead compounds for further optimization.

Erythropoiesis is a highly coordinated process that generates mature red blood cells from hematopoietic stem-progenitor cells (HSPCs). Erythropoietin (EPO) is a major regulator of erythropoiesis and binds to the erythropoietin receptor (EPOR), leading to increased erythroid differentiation and proliferation. MicroRNAs (miRs) are important developmental regulators, and distinct miR expression patterns are associated with specific stages of hematopoietic differentiation. Expression profiling of EPO-stimulated human HSPCs revealed increased expression of miR-513a-5p in early erythroid cells. Enforced expression of miR-513a in primary human CD34+ HSPCs promoted erythroid differentiation, as determined by cell-surface marker expression and increased levels of erythroid molecules including hemoglobin. Similar results were observed in human TF-1 erythroleukemia cells, where miR-513a stimulated erythroid differentiation including increased GATA1 and hemoglobin expression and decreased GATA2 expression, even in the absence of EPO. Notably, miR-513a promoted erythroid differentiation in EPOR knockout (KO) TF-1 cells, but not in GATA1 KO TF-1 cells, indicating that miR-513a requires GATA1, but not EPOR, to stimulate erythropoiesis. Further analysis revealed that enforced expression of miR-513a was associated with reduced c-Jun and phospho-c-Jun protein levels. Overexpression of c-Jun inhibited both EPO- and miR-513a-stimulated erythropoiesis. Conversely, c-Jun KO TF-1 cells had increased hemoglobin protein expression, even in the absence of EPO, phenocopying miR-513a overexpression. In summary, this study identifies miR-513a as a positive regulator of early human erythropoiesis and supports a role for miR-513a in promoting erythroid differentiation by modulating c-Jun expression and increasing GATA1 expression.

Abstract Activating mutations in KRAS occur at high frequency in colorectal, lung, and pancreatic cancers, which together account for a substantial proportion of global cancer mortality. Mutant KRAS is constitutively biased toward the GTP-bound state, driving persistent proliferative signaling, but simultaneously imposes oncogenic stresses that threaten cellular homeostasis. To sustain transformation, KRAS-mutant cells engage adaptive stress-response mechanisms, many of which converge on translational control mediated by the eIF2-eIF2B axis. While eIF2B is classically known as a guanine nucleotide exchange factor (GEF) for eIF2 during translation initiation, its potential role in directly regulating oncogenic signaling pathways has remained unexplored. Here, we identify a non-canonical function of eIF2B as a direct activator of mutant KRAS signaling. We demonstrate that eIF2B forms a tripartite complex with SOS and mutant KRAS at the plasma membrane (PM), thereby enhancing KRAS activation and tumorigenic signaling. Biochemical assays and structural modeling support an interaction between the catalytic ε subunit of eIF2B and the allosteric Ras-binding site of SOS, stabilizing SOS in an active conformation. This interaction potentiates SOS-mediated GDP/GTP exchange on mutant KRAS and promotes KRAS nanoclustering at the PM. Importantly, eIF2B exhibits marked specificity for mutant KRAS4B, but not KRAS4A, HRAS, or NRAS. This selectivity arises from KRAS4B’s unique polybasic membrane-anchoring domain and from eIF2B-dependent remodeling of plasma membrane lipid composition. eIF2B enhances glycosphingolipid (GSL) biosynthesis, particularly GM3 and SM4, through translational upregulation of B4GALT5, generating a membrane environment that preferentially supports mutant KRAS4B anchoring and signaling. Disruption of GSL synthesis impairs formation of the eIF2B:SOS:KRAS complex and selectively reduces mutant KRAS activation. Notably, eIF2B’s stimulation of mutant KRAS signaling occurs independently of eIF2α phosphorylation, separating its translational stress-response function from its oncogenic signaling role. Functionally, eIF2B promotes tumor growth specifically in KRAS-mutant cancer models, including human xenografts and an autochthonous KRAS G12C-driven lung adenocarcinoma model. Clinically, high expression of eIF2Bε correlates with poorer outcomes in patients with KRAS-mutant tumors. Our findings identify eIF2B as a previously unrecognized regulator of mutant KRAS-driven tumorigenesis that links translational control, membrane lipid remodeling, and oncogenic signaling. By coordinating SOS activation, KRAS membrane nanoclustering, and selective translation, eIF2B emerges as a central modulator of KRAS oncogenic output and a potential therapeutic and prognostic target. In vivo targeting of eIF2B supports its use as a combinatorial strategy with KRAS inhibition to broaden the therapeutic window in KRAS-mutant cancers. This abstract was edited and refined with the assistance of generative artificial intelligence to improve clarity and conciseness. Citation Format: Hyungdong Kim, Shiqi Diao, Kwang-Jin Cho, Hyun-Ro Lee, Junchen Liu, Pascal Egea, Tatu Pantsar, Milla Kurki, Nour Ghaddar, Shuo Wang, Jia Yi Zou, Mehdi Amiri, Ritchel Gannaban, John F. Hancock, Kylie M. Rice, Atsuo Sasaki, John Asara, Brajendra Tripathi, Douglas Lowy, Rosalie Lawrence, Maria Hatzoglou, Carlos R. Azpilcueta-Nicolas, Jean-Philip Lumb, John Columbus, Thomas J. Turbyville, Christopher B. Marshall, Mitsuhiko Ikura, Jay T. Groves, Nahum Sonenberg, Peter Walter, Antonis E. Koromilas. eIF2B Selectively Anchors and Activates Mutant KRAS4B [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RAS Oncogenesis and Therapeutics; 2026 Mar 5-8; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(5_Suppl_1):Abstract nr B001.

Broadly neutralizing antibodies (bnAbs) are evaluated as possible alternatives to standard antiretroviral treatment (ART) for maintaining control of HIV-1 replication and may enhance immune responses to reduce or control the viral reservoir. However, the immunological and virological effects of bnAbs in infants and children are unknown. We conducted a detailed analysis of proviral reservoir dynamics and antiviral immune responses in a unique group of young children from Botswana who started ART at birth and then stopped standard ART while receiving the bnAbs 10-1074 and VRC01-LS in a subsequent clinical trial. No quantitative changes in frequencies of proviral sequences were observed during bnAb treatment, but selection of genome-intact proviruses in transcriptionally repressive heterochromatin regions occurred in some study participants. Faster viral rebound following standard ART cessation was linked to elevated proportions of KIR2DL1-positive NK cells. In contrast, delayed viral rebound and more limited viral reservoir size were associated with elevated proportions of NKG2A-positive NK cells and with the HLA-B-21M signal peptide polymorphism. HIV-specific T cell responses were low in all study participants and unrelated to viral reservoir sizes or clinical outcomes following ART interruption. These results suggest that, in young children, specific NK cell subsets and KIR-HLA interactions might be linked to HIV-1 rebound kinetics after substitution of standard ART with bnAbs.

Background Mpox-related ophthalmic disease (MPOXROD) ranges from mild conjunctivitis to sight-threatening keratitis, however, data based on systematic ophthalmological assessment are scarce. We aimed to characterise the prevalence, features, and temporal evolution of MPOXROD during a clade Ib mpox outbreak. Methods We conducted MBOTE-EYE, a prospective ophthalmological sub-study, nested within a clinical characterisation cohort in Kamituga, South-Kivu, Democratic Republic of the Congo. All hospitalised patients with mpox confirmed by PCR in the prior 48 hours were eligible. Participants underwent comprehensive ophthalmological examination at enrolment, discharge, and days 29 and 59 post-diagnosis. Conjunctival swabs were collected for monkeypox virus PCR testing. MPOXROD was defined as conjunctivitis, scleritis, keratitis, uveitis, or optic nerve involvement. Risk factors were assessed using mixed-effects Poisson regression. Findings Between 28 October 2024 and 30 June 2025, 310 participants were enrolled (median age 14 years, IQR 2.5-25.0; 53.5% female, n=166/310). At enrolment, conjunctivitis was present in 36.1% (95% CI 31.0-41.6%, n=112/310), keratitis in 7.7% (95% CI 5.3-11.3%), and anterior uveitis in 0.6% (95% CI 0.2-2.3%). Overall, 43.2% (95% CI 37.8-48.8%) developed MPOXROD during follow-up, most often bilaterally. Visual acuity <8/10 occurred in 22.9% (95% CI 17.6-29.2%, n=24/310), and persistent blindness in 0.9% (95% CI 0.24-5.5%, n=2/225), due to ulcerative keratitis. Periorbital lesions (adjusted risk ratio [aRR] 2.82, 95% CI 1.40-5.69) and severe malnutrition (aRR 5.06, 2.25-11.38) were independently associated with MPOXROD. Conjunctival swabs with PCR Ct values < 25 occurred exclusively in participants with active MPOXROD. Interpretation Ophthalmic involvement in clade Ib mpox is common and frequently bilateral, with a substantial burden of keratitis and risk of vision loss, particularly in young children and severely malnourished individuals. These findings highlight the need for systematic eye examinations in mpox care and provide critical evidence to inform future trials of targeted ophthalmic therapies.

Proteolysis-targeting chimeras (PROTACs) and degraders have been developed against the hRpn13 fragment hRpn13Pru that is present in various cancer types. Testing the performance of these hRpn13Pru-targeting compounds in pharmacokinetic and efficacy studies has been stymied, however, by their poor solubility. Here, we develop a rapid and cost-effective platform to Screen and Characterize small molecule Nanosuspensions (SCaN). We discovered that the hRpn13Pru degrader XL44 adopts a crystalline state, preventing its bioavailability. The first phase of SCaN screens vehicles to identify lead XL44 nanosuspension formulations based on particle size consistency, including in biorelevant media, while the second phase evaluates stability over time. The lead nanosuspensions are then advanced to the third phase of SCaN to assess their physical and colloidal stability. This pipeline allows the formulation of poorly soluble compounds for single-dose pharmacokinetic and pilot multidose tumor mouse studies. We additionally analyzed our XL44 formulation morphologically by atomic force microscopy to find that the XL44 nanoparticles are predominantly globular, with a small population of rod-like particles. Using the optimal nanosuspension determined by SCaN, XL44 slowed tumor growth in a myeloma xenograft model at 35% inhibition with a 48-72 mg/kg treatment regimen. This case study is the first in vivo demonstration that hRpn13Pru-targeting degraders can inhibit tumor growth, and the efficacy shown here motivates the development of more potent hRpn13Pru degraders. Broadly, our SCaN platform is designed for poorly soluble drug candidates to allow for pilot in vivo testing.

Human papillomavirus (HPV) is one of the most common sexually transmitted infections globally, infecting most sexually active individuals. HPV infection is usually asymptomatic and often transient; however, some infections can persist and cause cancer. In fact, HPV is the main cause of cervical cancer and can also cause cancer of the penis, anus, vagina, vulva, mouth, or throat. Fortunately, there are seven approved vaccines available that are highly effective at preventing infection and HPV-associated cancers. Nevertheless, there is still a need for a better understanding of the mechanisms underlying natural and vaccine-elicited immunity to HPV. Immune responses after natural infection or vaccination encompass both humoral and cell-mediated responses. In natural infection, cell-mediated responses are believed to be responsible for the elimination of virus-infected cells. However, many individuals do not appear to seroconvert following infection. Conversely, vaccination elicits long-lasting antibody levels and robust cell-mediated immune memory. Despite the number of publications on HPV infection and prophylactic vaccine responses, many immune mechanisms, as well as the influence of infection site, remain to be elucidated. In addition, there is an increasing interest to understand the potential role of specific effector functions of antibodies and T cell subsets on vaccine-elicited protection-particularly, how these mechanisms may differ with vaccine type, adjuvant, and dosing schedule. Finally, standardization of relevant immune assessments is critical to facilitate comparisons across studies and new vaccine developments.