Epitranscriptomic modifications, particularly N6-methyladenosine (m6A), have emerged as critical regulators of RNA stability, localization, and translation, shaping immune responses and tumor progression. In B-cell biology, m6A modifications influence germinal center formation and antigen-driven differentiation, underscoring their importance in immune regulation. Among m6A regulators, ALKBH5 (RNA demethylase) is pivotal in removing methylation marks and modulating gene expression in diverse cellular contexts. Despite advancements in understanding m6A dynamics, the mechanistic interplay between m6A demethylation and B-cell receptor (BCR) signaling pathways still needs to be explored. This study reveals a novel regulatory axis involving ALKBH5, treRNA1 (Translation Regulatory Long Non-Coding RNA 1), and DDX46 (RNA helicase). Upon activation signals, ALKBH5 and treRNA1 translocate to the nucleus, forming a functional complex with DDX46 to orchestrate the removal of m6A modifications on key transcripts, including those involved in BCR signaling. This demethylation enhances transcript stability and facilitates cytoplasmic export through interaction with the RNA-binding protein HuR, promoting efficient translation. Disruption of this axis, via loss of ALKBH5, DDX46, or treRNA1, led to impaired transcript processing and diminished BCR-related gene expression, highlighting the critical role of m6A demethylation in maintaining RNA dynamics. These findings uncover a previously unrecognized epitranscriptomic mechanism driven by the ALKBH5-treRNA1-DDX46 complex, with significant implications for B-cell functionality, immune regulation, and oncogenic pathways. Targeting this axis offers a promising avenue for developing therapeutic strategies in cancer and immune-related disorders where m6A dysregulation plays a central role.

Gastrointestinal mucormycosis is a rare infection in solid organ transplant recipients. Our patient, a 79-year-old male, presented with severe dysphagia and odynophagia about 2 weeks after receiving a renal transplant. An upper gastrointestinal (UGI) endoscopy revealed esophagitis and gastric ulceration, the cultures from which grew Rhizopus species. A usual treatment strategy should include Amphotericin B as monotherapy or in combination with Posaconazole or Isavuconazole for such infections. Our patient was treated with Isavuconazole monotherapy, in an effort to minimize renal toxicity from Amphotericin B to the new allograft. Unique to our case was a successful clinical response and resolution of UGI lesions with Isavuconazole monotherapy. Due to the vagueness of presenting symptoms, such infections can be easily missed in an immunocompromised patient which can have tragic outcomes. Prompt diagnosis and modulation of immunosuppression are essential to decrease mortality and morbidity. Isavuconazole is a novel agent and can be used as a monotherapy for such infections, especially in renal transplant recipients.

Won Sok Lee, Elizabeth Margolskee; Leukoerythroblastosis and plasmacytoid lymphocytes in a child with SARS-CoV-2–associated multisystem inflammatory syndrome,

High-dose acetaminophen (AAP) with N-acetylcysteine (NAC) rescue is among the few treatments that has shown activity in phase I trials without achieving dose-limiting toxicity that has not progressed to evaluation in later line studies. While the anti-tumor effects of AAP/NAC appear not to be mediated by glutathione depletion and free radical injury, the mechanism of anti-tumor effects of AAP/NAC has not been definitively characterized. In vitro, the effects of AAP/NAC were evaluated on bone marrow derived macrophages. Effects of AAP on IL-4/STAT6 (M2) or IFN/LPS/STAT1 (M1) signaling and downstream gene and protein expression were studied. NAC reversed the AAP toxicity in the normal liver but did not reverse AAP cytotoxicity against tumor cells in vitro. AAP/NAC selectively inhibited IL-4-induced STAT6 phosphorylation but not IFN/LPS-induced STAT1 phosphorylation. Downstream, AAP/NAC inhibited IL-4 induction of M2-associated genes and proteins but did not inhibit the IFN/LPS induction of M1-associated genes and proteins. In vivo, AAP/NAC inhibited tumor growth in EF43.fgf4 and 4T1 triple-negative breast tumors. Flow cytometry of tumor-associated macrophages revealed that AAP/NAC selectively inhibited M2 polarization. The anti-tumor activity of high-dose AAP/NAC is lost in macrophage-depleted mouse syngeneic tumor models, suggesting a macrophage-dependent mechanism of action. In conclusion, our study is the first to show that high-dose AAP/NAC has profound effects on the tumor immune microenvironment that facilitates immune-mediated inhibition of tumor growth.

High dose acetaminophen (AAP) has demonstrated promising results in early phase clinical trials for treatment of advanced malignancies. When administered concurrently with the CYP2E1 inhibitor fomepizole, AAP can be dose-escalated 100-fold relative to standard dosing without liver toxicity and without compromising anti-tumor activity. The current study used a 23-plex flow cytometry panel to study AAP-induced changes in the tumor immune microenvironment of syngeneic mouse breast tumors. Effects of AAP on macrophage function and antigen presentation, alone and in combination with PD-1 antibodies, were evaluated. Findings demonstrated that the vast majority of CD45+ cells in the triple negative breast cancer model are CD11b+ cells of the innate immune system. The CD11b+ cells in the tumor micro-environment of vehicle-treated mice were mostly comprised of GR1+ myeloid derived suppressor cells. On the other hand, the CD11b+ cells in the high dose AAP-treated mice were mostly of the activated macrophage phenotype (F4/80+CD80+MHCII+). In vitro studies were performed to better understand AAP effects on macrophage function. It was demonstrated that AAP enhances phagocytosis as well as antigen presentation by macrophages to antigen-reactive T-cells. These effects are amplified when PD-1 antibodies are combined with AAP in the in vitro antigen presentation assay. Furthermore, AAP has synergistic anti-tumor activity in vivo when combined with PD-1 antibody therapy, an effect that is macrophage dependent. The present study demonstrates profound AAP-induced changes in the tumor immune microenvironment including the differentiation of CD11b+ cells towards an activated "M1" macrophage phenotype.

Background/Objectives. Triple-negative breast cancer (TNBC) and pancreatic ductal adenocarcinoma (PDAC) are two of the deadliest adult cancers. High-dose acetaminophen (AAP) has anti-cancer activity when given in conjunction with CYP2E1 inhibitors to block liver toxicity. However, the administration of high doses of AAP presents practical challenges stemming from limited water solubility, making it difficult to create a concentrated treatment solution in limited volume. Propacetamol (PROP) is a water-soluble AAP pro-drug that has been used clinically as an IV AAP formulation for analgesia. Methods. We sought to investigate the pharmacokinetics, safety and anti-cancer activity of PROP in comparison to AAP using transplantable syngeneic models of TNBC and PDAC. Results. In vivo, PROP was rapidly converted to AAP within minutes of administration. PROP demonstrated enhanced effectiveness in suppressing tumor growth in the TNBC and PDAC syngeneic murine tumor models compared to AAP. The enhanced efficacy of PROP appears to stem from increased cellular uptake, leading to intracellular AAP concentrations that are 2.7-fold higher within 5 min compared to cells treated with unmodified AAP. PROP demonstrated enhanced modulation of intracellular JAK/STAT signaling, a key mediator of AAP anti-cancer activity, using both murine and humanized models. STAT3 and STAT6 inhibition by PROP led to modulation of macrophage polarization, likely contributing to its anti-TNBC and anti-PDAC activity. While parenteral administration is the preferred route of administration for PROP in anti-cancer indications, we also evaluated the safety and efficacy of oral PROP in comparison to AAP. High-dose PROP demonstrated improved safety following oral administration compared to AAP in the BALB/c murine model while maintaining anti-cancer activity in vivo. Conclusions. PROP, an AAP pro-drug, demonstrates enhanced intracellular delivery of AAP and in vivo anti-cancer activity compared to unmodified AAP, setting the stage for investigation as an anti-cancer drug across different indications.