Cells terminally arrested in the cell cycle that exhibit a distinct secretory phenotype are referred to as senescent. These cells play a complex role during tumor progression; they can inhibit or promote tumor growth depending on disease stage. We developed a mouse model that allows monitoring and selective elimination of cells expressing high levels of the cyclin-dependent kinase inhibitor p16 and interleukin-6. These mice, termed SuSe (suicidal senescence), were crossed with the mouse mammary tumor virus–polyomavirus middle T antigen (MMTV-PyMT) model of breast cancer. Functional characterization in SuSe/PyMT mice confirmed that depletion of senescent cells (senolysis) in early and late lesions accelerated and decelerated tumor growth and metastasis, respectively. Tumor acceleration was attributed to expansion of immunosuppressive, protumorigenic macrophages. C-C motif chemokine ligand 2 was identified as an autocrine chemokine essential for their recruitment and maintenance. Depletion of these macrophages reversed the effects of senescent cell clearance, rendering senolysis antitumorigenic even at early stages. Our results suggest that targeting immunosuppressive macrophages can preserve the benefits of senolysis while mitigating adverse effects.

AXIN1 (axis inhibition protein1), as a rate-limiting component of canonical Wingless-type mouse mammary tumor virus integration site (Wnt)/β-catenin signaling pathway, may influence midbrain dopaminergic neurons. A recent genome-wide association study identified AXIN1 as a candidate gene for Parkinson's disease (PD). Our study aimed to investigate the potential relevance of AXIN1 single nucleotide polymorphisms (rs13337493 and rs9921222) in the risk, clinical characteristics, and pathology of PD. Data were collected from the Northern Han Chinese and Parkinson's Progression Markers Initiative (PPMI) cohorts. Associations between AXIN1 variants, PD-related biomarkers, and clinical manifestations were analyzed. Both loci were identified as risk factors in the Northern Han Chinese population, and the Aallele of rs13337493 [odds ratio (OR) 1.320, 95% confidence interval (CI) 1.052, 1.653, Pc = 0.036] and the Tallele of rs9921222 (OR 1.351, 95%CI 1.045, 1.747, Pc = 0.042) showed increased susceptibility to PD. The risk effect of rs9921222 was predominant in the male cohort (OR 1.504, 95%CI 1.058, 2.139, Pc = 0.044). Rs13337493 was related to worse motor function in white individuals, which was represented by the Hoehn & Yahr stage (OR 2.775, 95%CI 1.195, 6.447, Pc = 0.036). It also correlated with compensatory elevation of cerebrospinal fluid (CSF) 3,4-dihydroxyphenylalanine (DOPA, β = 0.040, 95%CI 0.007, 0.073, Pc = 0.038). Our findings support a gatekeeper role for AXIN1; its polymorphisms contribute to increased PDsusceptibility and accelerated motor progression, yet may also trigger a compensatory presynaptic response, as evidenced by elevated CSF DOPA levels, to counteract neurodegeneration. Future studies should include larger sample sizes, more diverse ethnic populations, and protein-level investigations.

Abstract Metastatic relapse may occur long after eradication of the primary tumor in part due to dormancy of the disseminated cancer cells (DCCs). The treatment of metastases remains a relevant clinical challenge, as an estimated two-thirds of cancer-related deaths are caused by metastatic disease. Thus, investigating the basis for reactivation of dormant DCCs is pertinent to the treatment of metastatic cancers. Our lab previously demonstrated that viral infection induces expansion of dormant breast cancer cells in the lungs, with a marked upregulation of extracellular matrix (ECM) component-encoding mRNAs in proliferative lesions. Indeed, recent literature suggests that cell-extrinsic factors, including the immune microenvironment and ECM, influence dormancy status. Collagen, the major component of the ECM, can direct cell proliferation, migration, and invasion, as well as promote cancer immunoevasion. Here, we seek to disambiguate the roles of three major fibrillar collagen types – Collagen I, III, and V – thought to play a role in cancer cell dormancy. Mouse Mammary Tumor Virus (MMTV) Her2+ mouse models were utilized to model high-latency, dormant metastatic breast cancer and challenged with Influenza A virus. Lung tissue collected longitudinally over the course of infection was stained for the collagen subunit proteins Col3a1 and Col5a1 and the breast cancer cell marker Her2. Second Harmonic Generation (SHG) was performed to visualize Collagen I architecture. Images were evaluated in QuPath, and fluorescence intensity data were used to quantify and classify cell types for analysis.Induced bronchial-associated lymphoid tissue (iBALT) and immune infiltration are evident in lungs from mice challenged by influenza virus. Interestingly, proximity to the iBALT region is correlated with increased expression of Collagen III by DCCs, though this pattern of expression does not emerge in Collagen V. Fluorescence data suggest DCC production of both collagen subtypes increases over the course of infection and remains high following viral clearance. Correspondingly, bulk RNA-seq data demonstrate both Collagen III and V subunit transcription are elevated in DCCs from flu-infected lungs compared to control. However, this process does not appear to be interleukin 6 dependent. Preliminary SHG data also indicate extracellular matrix remodeling by proliferative lesions.Though Collagen III has been previously demonstrated to promote the dormancy niche, our data instead suggest an association with DCC awakening and expansion at immune-rich sites in the lung. Since this collagen signature is largely absent in spontaneous lesions, next steps involve investigating cytokine signaling in this apparently immune-directed expansion. Differential upregulation of ECM proteins may in part justify the mixed epithelial-mesenchymal cancer cell population seen in proliferative lesions and further our understanding of cell-extrinsic factors implicated in the adoption of, and exit from, the dormant phenotype. Citation Format: Bailey S. Kane, Bryan J. Johnson, James V. DeGregori. Influenza virus-induced expansion of dormant metastatic breast cancer in the lung alters tumor collagen program [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Cancer Evolution: The Dynamics of Progression and Persistence; 2025 Dec 4-6; Albuquerque, NM. Philadelphia (PA): AACR; Cancer Res 2025;85(23_Suppl):Abstract nr A017.

Lymphatic Malformation: Classification, Pathogenesis, and Therapeutic Strategies.

Apobec3 (A3, apolipoprotein B editing complex 3) is a cytidine deaminase with broadly antiretroviral activity. A3 is packaged in virions and converts cytidines to uracil (C > U) in viral minus-strand DNA during reverse transcription, resulting in guanosine to adenosine (G > A) mutations in the viral plus strand. Mouse Apobec3 (mA3) mutagenizes numerous infectious retroviruses and some families of endogenous retroviruses. Here we show that endogenous mouse mammary tumor viruses, termed Mtvs, show a range of mA3 hypermutation from trace levels to an extreme example, Mtv21, that sustained a catastrophic, genome-wide reduction of G content to 10.8%; this level is associated with the contemporaneous generation of new preferred trinucleotide target sites by mutagenesis of consecutive cytidines. Although newly inserted proviruses have identical long terminal repeats (LTRs), mA3 can disproportionately generate G > A substitutions specific to the Mtv 3' LTR. Individual hypermutated Mtvs display two different mA3 target site context preferences that correspond to those of the two mA3 alleles found among inbred strains of laboratory mice. Mtv-positive Mus musculus subspecies screened for these mA3 alleles unexpectedly revealed 20 distinct mA3 haplotypes with different combinations of replacement mutations at the 15 sites that distinguish the two inbred strain alleles, 11 of which show signatures of positive selection. These data show that mA3 deamination can have a major impact on the genomic integrity of Mtvs, and that mA3 is actively evolving within this single mouse species suggestive of high-impact genetic conflicts over a short evolutionary time frame.IMPORTANCEThe antiviral cytidine deaminase Apobec3 (apolipoprotein B editing complex 3) mutates retroviral DNA copies generated during new infections. Although such mutagenesis of replicating mouse retroviruses has been reported to be modest, here we show that many germline copies of mouse mammary tumor viruses (Mtvs) have sustained significant to massive levels of mouse Apobec3 (mA3) editing. mA3 hypermutation can also disproportionally affect one of the two otherwise identical viral long terminal repeats and can create new preferred target sites in the viral genome substrate by mutating successive cytosines. The edits in individual Mtvs correspond to the different target sequence preferences of the two inbred mouse strain mA3 alleles, but examination of allelic variation in wild mice of the species Mus musculus identified 18 additional variants and signatures of diversifying selection, a display of unusually rapid evolution within a single species over a short time frame.

Background:Chronic pain and cancer interact bidirectionally, with pain enhancing sensory peptides and potentially promoting tumor growth. Despite this, most chemotherapy-induced neuropathic pain (CIPN) studies overlook the contribution of cancer itself to neuropathy, focusing instead on chemotherapy-induced mechanisms. Animal models of chemotherapy-induced neuropathic pain (CINP) have been developed by injecting chemotherapeutic drugs such as paclitaxel into normal animals without cancer. This study aimed to develop a new model in mouse mammary tumor virus–polyomavirus middle T antigen (MMTV-PyMT) mice, a widely used breast cancer model with normal immune function.Results:The percentage of positive response (PPR) of paclitaxel-injected MMTV-PyMT mice increased (about 20%; baseline, 10%) on day 4, reached the highest levels (50%–60%) on days 6–9, and then plateaued by day 29. In comparison, the PPR of paclitaxel-injected C57BL/6 was less than 10% on days 0–6, was about 40% on day 9, and then plateaued by day 29. Breast tumor–bearing mice exhibited an earlier onset and greater severity of paclitaxel-induced pain behaviors than tumor-free C57BL/6 mice. Systemic LGK-974 ameliorated paclitaxel-induced pain behaviors in MMTV-PyMT mice. Active β-catenin was detected in neurons and satellite cells of the dorsal root ganglia.Conclusions:Paclitaxel-induced neuropathic pain model in breast tumor–bearing female MMTV-PyMT mice may be a useful animal model for investigating the analgesic effects and underlying mechanisms for CINP in breast cancer patients as well as the interplay between CINP development and cancer progression.

Hair loss (alopecia) is a common disorder caused by an interruption in the body’s cycle of hair production. This pathology negatively affects the psychoemotional state of patients and significantly reduces their quality of life. The currently available medical treatments (including minoxidil therapy) are effective in arresting the progression of the disease; however, they allow only partial regrowth of hair at best. A significant clinical result occurs only with regular drug use. There is still great interest in finding new drugs for the treatment of alopecia. In this study, we aimed to examine the effect of an aqueous dispersion of unmodified fullerene C60 (ADF) on hair growth. ADF, produced by a unique technology, is biocompatible and non-toxic. Nu/nu mice were subcutaneously injected (2 μg/animal) every two days for a period of 11 days with ADF and, for control purposes, with phosphate-buffered saline (PBS). It was shown that ADF stimulated hair growth. Histological analysis of the nu/nu mice skin areas showed that animals treated with ADF had significantly more (about twice as many) hair follicles in the anagen phase compared to mice treated with PBS. The effect on hair growth persisted even after discontinuation of ADF administration. Analysis of gene expression demonstrated that ADF affected the Wnt-signaling pathway, increased the expression of the Wnt10b (wingless-type Mouse Mammary Tumor Virus integration site family, member 10B) factor, angiogenetic factors, and downregulated tumor necrosis factor-alpha levels. We propose that the mechanism of ADF action is likely related to its ability to attract macrophages to the hair follicle microenvironment and promote their polarization to the M2 phenotype. In addition, using molecular modeling, we tried to substantiate our hypothesis about the interaction of ADF with the adenosine A2A receptor, which may cause a decrease in tumor necrosis factor-alpha production. Thus, ADF may become a promising drug for the development of new approaches to the treatment of alopecia associated with immune disorders.

Decitabine (DAC), a DNA methyltransferase inhibitor (DNMTi), is clinically effective in hematological malignancies such as myelodysplastic syndrome and acute myeloid leukemia, but its precise antineoplastic mechanisms remain incompletely understood. Beyond promoter demethylation, DAC is known to activate endogenous retroviruses (ERVs) and trigger type I interferon (IFN-I) responses, a phenomenon known as viral mimicry. The aim of this study was to investigate the roles of the mouse mammary tumor virus (MMTV) and interferon-β (IFN-β) in DAC-mediated tumor suppression. We employed two murine tumor models-4T1 mammary carcinoma and MC38 colon adenocarcinoma-in syngeneic immunocompetent mice, immunodeficient nude mice, and in vitro cultures. RNA and protein expression were assessed by quantitative PCR and immunoblotting, while functional contributions of MMTV and IFN-β were tested using short hairpin RNA (shRNA) knockdowns. DAC treatment suppressed tumor growth and pulmonary metastasis in vivo and inhibited cancer cell proliferation in vitro. It induced transcription of MMTV and expression of IFN-β, with a strong negative correlation between MMTV Env protein levels and tumor mass. Knockdown of either MMTV or IFN-β conferred resistance to DAC, confirming their functional roles. Reciprocal regulation was observed: MMTV knockdown reduced IFN-β expression, while IFN-β knockdown increased MMTV Env accumulation. Furthermore, DAC upregulated interferon regulatory factor 7 (IRF7), but this effect declined during prolonged treatment, suggesting a temporally restricted therapeutic window. In conclusion, our findings provide in vivo support for the viral mimicry hypothesis and demonstrate that MMTV and IFN-β contribute to DAC-mediated tumor suppression. The observed IRF7 downregulation and potential induction of immune checkpoints highlight the importance of therapeutic strategies combining DNMTis with immune checkpoint blockade to sustain antineoplastic efficacy.

Advanced spontaneous multifocal metastatic mammary tumours induce cardiac dysfunction and extensive metabolic alterations in mice

The mouse mammary tumor virus (MMTV) has been identified as potentially oncogenic, and its presence in milk was reported and discussed. However, with respect to breast cancer etiology, the transmission routes for these viruses are not known. In this context, the objective of this study is to assess the presence of MMTV-like virus in breast milk and to explore the associated factors of its presence among healthy lactating women in Morocco. In this prospective study, milk samples were collected from 44 lactating women recruited from the Souissi Maternity Hospital of Rabat in Morocco. MMTV-like DNA was identified by polymerase chain reaction amplification using specific primers targeting the env gene. The prevalence of the MMTV-like virus was 45.5% (20/44). Statistical analysis revealed a significant association with the use of henna. It seems that it increases the risk of the presence of MMTV-like virus in breast milk. The hypothesis could be the possible contamination of henna sold in bulk in local markets by urine and feces of mice during storage. Nevertheless, these results need to be confirmed by multicenter studies to thoroughly investigate the impact of other factors and the potential contamination of henna with the virus through urine and feces of mice during storage.

Chrousos syndrome is a rare disease mainly caused by inactivated mutations in the NR3C1 gene, which encodes the human glucocorticoid receptor (GR). We reported a male patient of Chrousos syndrome, who had a novel nonsense mutation (c.1839T > A, p. Tyr613Ter) in NR3C1 and presented with oligospermic and infertility but without other typical clinical manifestation. The aim of this study is to explore the molecular mechanisms that cause the unique clinical manifestations in this patient. Mutant plasmids were transfected to HEK293T and HeLa cells to evaluate glucocorticoid sensitivity and GR expression. Proteomic and further cellular experiments were used to illustrate the mechanism of GR expression change induced by mutation. The mutation causes the deletion of the ligand-binding region of the GR (GR Y613*). Compared with GR wild type (GR WT), GR Y613* had a decreased affinity with dexamethasone, reduced nuclear translocation and decreased transactivation of the glucocorticoid response gene mouse mammary tumor virus promoter. GR Y613* caused decreased protein but unchanged gene expression. E3 ligase STUB1 was identified to regulate ubiquitin-proteasome degradation of GR Y613*. Compared with other human tissues and cell types, expression of STUB1 in testis and Sertoli cells was low. GR Y613* causes reduced sensitivity to glucocorticoids. STUB1 promotes ubiquitination and degradation of GR Y613*. Low expression of STUB1 in human testis compared with other tissue might cause accumulation of GR Y613*, as a potential explanation of the infertility of Chrousos syndrome.

Abstract The Epidermal Growth Factor Receptor (EGFR) belongs to a group of Receptor Tyrosine Kinases (RTKs) that are a part of the HER family. EGFR mediates many processes in the cell including proliferation, migration, and survival however its overexpression is correlated with poor prognosis in several epithelial cancers including Triple Negative Breast Cancer (TNBC). In healthy cells, EGF binds to EGFR dimerizes and undergoes transphosphorylation, and can then be intracellularly imported where it is taken to the early endosome and awaits ubiquitination. This signals readiness to be taken to the lysosome where it undergoes degradation or in some cases, gets recycled. In cancerous cells, however, ubiquitination gets inhibited due to their loss of polarity. This results in failure to signify readiness to be taken to the lysosome which allows EGFR to completely evade degradation and undergo nuclear localization. This process is initiated by the binding of Sorting Nexin 1 (SNX1), a protein responsible for the regulation of trafficking, to EGFR. Considering the interaction between Sorting Nexins and RTKs causes oncogenic activity, it was hypothesized in this lab that a therapeutic that can modify this interaction can alter tumor-specific retrotranslocation. In order to target these interactions, the therapeutic peptide, cSNX1.3, was developed. cSNX1.3 is a cell-penetrating peptide with a Protein Transduction Domain that allows for the delivery of peptides across the cell membrane and into the intracellular domain. cSNX1.3 interacts with EGFR when it’s in the long-lived endosome and binds in competition with SNX1. When cSNX1.3 is bound to EGFR, it is able to inhibit the nuclear localization of the RTK and as a result, inhibit its oncogenic activity. In order to fully evaluate the tumor-regressing abilities of cSNX1.3, we used an immunocompetent model of transgenic Whey Acidic Protein - Transforming Growth Factor alpha (WAP-TGFα) mice, whose mammary gland tumors are EGFR dependent. These mice were treated with cSNX1.3 or the control drug, cPTD4, over the course of 4 weeks. After completion of treatment, it was determined that the tumors of the cPTD4-treated mice continued to grow whereas the tumors of the cSNX1.3-treated mice began to regress. We then decided to construct an additional study using another immunocompetent mouse model that would also demonstrate how cancer metastasis reacted to cSNX1.3 treatment, given that metastasis is typically what makes breast cancer fatal in humans. For these reasons, we decided to use a model of transgenic Mouse Mammary Tumor Virus - Polyoma Middle T (MMTV-PyMT) mice. Conducting an evaluation of cSNX1.3 using this model that closely resembles the function of metastatic breast cancer in humans, will allow us to better understand the future of cSNX1.3 as a breast cancer therapeutic for human applications. Citation Format: Delina J. Denogean, Barbara Sands, Joyce Schroeder. The effect of cSNX1.3 on MMTV-PyMT tumor growth and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 2939.

Aim: Breast cancer (BC) is the leading cause of female cancer-related death worldwide. The high incidence of BC has sparked interest in the viral agents role in its development. Identifying co-infection involving potential oncogenic viruses, such as human papillomavirus (HPV), Epstein-Barr virus (EBV), mouse mammary tumor virus (MMTV), and Simian virus 40 (SV40), may improve early detection and treatment strategies of BC. However, the involvement of these viral co-infections in invasive breast cancer (IBC) has not been elucidated. Methods: To investigate this eventual co-infection, screening of viral DNAs isolated from 120 fresh IBC tissue biopsies was performed using a polymerase chain reaction. Statistical analysis were conducted to assess the correlation between viral prevalence and IBC clinicopathological features. Results: Our findings revealed the prevalence of EBV (67.1%), HPV (45.7%), MMTV (72.9%), and SV40 (22.9%) in IBC samples. Co-infection rates were as follows: EBV/HPV (17.14%), EBV/MMTV (22.86%), EBV/SV40 (4.28%), and HPV/MMTV (11.43%). Triple infection with EBV, HPV, and MMTV was observed in 5.71% of cases. Statistically significant associations were identified between: EBV and histological grade, tumour size and stage, and progesterone receptor (PR) and estrogen receptor (ER) status; HPV and histological grade, tumour stage, and PR status; MMTV and histological type, as well as PR and ER status; and SV40 and histological grade and PR status. Conclusions: Although the prevalence of HPV, EBV, MMTV, and SV40 coinfection in Moroccan IBC patients is low, their potential synergistic role in breast carcinogenesis needs to be further investigated, in order to identify new etiological factors for BC.

Endogenous retroviruses (ERVs) are copies of viral genomes inserted into host chromosomes, producing a fossil record of past infections and virus-host co-adaptations. ERVs of mouse mammary tumor viruses (Mtvs) were found in all common laboratory strains, all Mus musculus subspecies, and a sister species, Mus spretus. Most laboratory mouse Mtvs predate inbred strain origins and were acquired by M. musculus domesticus, but although widely shared among strains, none of these were found in wild mice. Among wild mouse Mtvs, only one showed a broad geographic distribution. All M. musculus subspecies carry Mtvs with a large envelope deletion corresponding to the processed mRNA for the viral rem gene; such Mtvs likely derive from spliced viral mRNA. The Mtv sag gene responsible for resistance to exogenous infection is under purifying selection and has been subject to recombination, whereas the Mtv envelope and its cellular receptor show no evidence of genetic conflicts.

The viral hypothesis for human sporadic breast carcinoma is based on the murine model of Mouse Mammary Tumor Virus (MMTV)‐induced mammary tumors. Known risk factors like estrogens, obesity, and alcohol do not play a direct causal role. The Human Betaretrovirus (HBRV), also called Human Mammary Tumor Virus (HMTV), is the human homolog of MMTV, implicated in sporadic breast carcinoma (80% of ductal carcinoma in situ and 40% of invasive tumors). In contrast, hereditary breast carcinomas lack viral sequences. Murine mammary tumor histotypes are determined by specific viral strains activating definite molecular pathways via insertional mutagenesis. Similarly, the diverse histotypes observed in human invasive breast carcinoma may be influenced by a viral etiology. A study of 253 invasive breast carcinoma cases, representing 15 histotypes, detected HBRV/MMTV‐ENV sequences in 20%, consistent with international literature. All histotypes tested positive except those linked to hereditary syndromes, such as medullary, apocrine, and metaplastic carcinoma. This distinction reinforces the reported lack of association between HBRV/HMTV and hereditary breast cancer, while supporting a viral etiology for sporadic carcinoma. Relevant characteristics of sporadic histotypes align with the “hit and run” hypothesis of viral carcinogenesis. Histotype differences may result from molecular pathways activated by Int genes, though mechanism beyond insertional mutagenesis and the possibility of specific HBRV strains cannot be ruled out. The potential for detected viral sequences to originate in human tumors from endogenous MMTV or contamination with murine material is critically examined.

Over the past few decades, women have been troubled by grave diseases such as breast cancer, which are biologically and molecularly classified as hereditary diseases. Even though the risk of other cancers is relatively different and the downstream pathway of genetic mutation differs from breast cancer, the continued transformation of genes such as BRCA1 and BRCA2 leads to breast cancer malignancy. Notably at the molecular level, a parallel connection between the normal growth of breast and the progression of mammary cancer where the breast cancer stem cells play a crucial role in the advancement of mammary carcinoma. Arguably, several significant signaling pathways, for instance, ER signaling, HER2 signaling, and Wnt signaling control the typical breast development as well as breast stem cells, thereby cell proliferation, cell differentiation, and cell motility are involved. Incidentally, the Mouse Mammary Tumor Virus (MMTV) is notable among the unexplained viral components influenced by virus-corrupting mammary carcinomas. According to the genesis, MMTV proviral DNA is integrated into mammary epithelial cells, and genomic lymphoid cells during viral replication and triggers the progression of cellular oncogenesis. This overview reveals the deadliest theories on breast cancer, molecular mechanisms, and the MMTV transmission cycle. To establish prevention therapies that are both acceptable and efficacious, addressing apprehensions related to the toxicity of these interventions must be a preliminary hurdle to overcome.

Abstract Background We have been investigating the role of viral infections in the development of inflammatory bowel disease (IBD) in genetically predisposed individuals. Using the SvEv IL10 -/- model of colitis, we found evidence of mouse mammary tumor virus (MMTV) infection and modulated the disease with combination antiretroviral therapy. Reducing MMTV RNA in the colon lowered inflammation, cytokine levels, and microbial dysbiosis. Our results showed viral superantigen (SAg) activity, which MMTV uses to replicate in lymphocytes. MMTV also exploits IL-10 to tolerize the host, and we hypothesize that IL-10 deficiency leads to colitis in this model (Armstrong et al., Microbiome, 2023). Aims This study investigates SAg activity in patients with IBD, focusing on Crohn’s disease (CD) and ulcerative colitis (UC) by analyzing T cell receptor variable beta region (TCR-Vβ) skewing. Additionally, we assess TCR diversity and selective enrichment of specific TCR-Vβ families by comparing IBD patients with healthy subjects and analyzing TCR profiles between active and inactive disease. Methods Peripheral blood samples (n > 2500) from the IBD Plexus database were analyzed to evaluate TCR-Vβ skewing as an indicator of SAg activity in patients with IBD. Comparisons of TCR-Vβ family usage were made between healthy subjects and those with CD and UC. Statistical analyses were performed in R, using unpaired t-tests and Bonferroni correction. TCR diversity was assessed using the Inverse Simpson Index (ISI) for CD, UC, and age-matched healthy controls. ISI values were also compared between active and inactive disease states. Results An analysis of TCR repertoires from PBMCs in CD (n=1901), UC (n=913), and healthy controls (n=725) revealed greater SAg activity in CD and UC patients than in controls. In healthy individuals, the TCR-Vβ repertoire was diverse and polyclonal, while IBD patients had skewed repertoires. TRBV-03, TRBV-09, and TRBV-24 were consistently enriched in CD and UC patients across all age groups. The inverse Simpson’s index showed increased T cell clonality in CD and UC patients. Additionally, TCR diversity was significantly lower in patients with active disease than in those with inactive disease. Conclusions Our study underscores the role of SAg activity in IBD, particularly in CD and UC. We observed notable TCR-Vβ skewing and TRBV subset enrichment in IBD patients, accompanied by increased T cell clonality, especially in active disease. This selective skewing of TCR-Vβ subsets suggests involvement of distinct SAgs. While bacterial SAgs are often linked to severe disease, our results indicate a contribution from non-bacterial SAgs, highlighting a potential connection between SAg activity and the onset of IBD. Funding Agencies CCC

Superantigen-induced (Sag-induced) autoimmunity has been proposed as a mechanism for many human disorders, without a clear understanding of the potential triggers. In this issue of the JCI, McCarthy and colleagues used the SKG mouse model of rheumatoid arthritis to characterize the role of Sag activity in inflammatory arthritis by profiling arthritogenic naive CD4+ T cells. Within the diseased joints, they found a marked enrichment of T cell receptor-variable β (TCR-Vβ) subsets that were reactive to the endogenously encoded mouse mammary tumor virus (MMTV) Sag. Arthritis was improved using reverse transcriptase inhibitors. Moreover, depletion of MMTV Sag-activated TCR-Vβ subsets affected the ability of transferred activated CD4+ T cells to induce disease in mice with severe combined immunodeficiency (SCID). Further virological studies should determine whether endogenous or exogenous MMTV is necessary or sufficient to trigger inflammatory arthritis in the SKG model.

Recent studies have established a strong connection between gut microbiota and the tumor immune microenvironment. Beetroot (BRT) has emerged as a promising functional food for cancer prevention and treatment, although its specific effects on breast cancer remain unclear. This study investigates the impact of BRT on polyomavirus middle T antigen (PyMT)-induced breast cancer by examining the gut microbiome, metabolites, and immune responses. Dietary supplementation of 80 g BRT powder per 1000 g of standard diet (8% w/w, 80 g per kg) significantly inhibited tumor growth and metastasis in mouse mammary tumor virus (MMTV)-PyMT (FVB) mice, while simultaneously enhancing anti-tumor immunity. 16S rRNA sequencing revealed that BRT supplementation altered the gut microbiota, notably increasing the abundance of Lachnospiraceae and Ruminococcaceae. An antibiotic (ABX) experiment confirmed that BRT restores gut microbiota balance, thereby enhancing anti-tumor immunity. Metabolomics and ELISA assays demonstrated that BRT regulates diacylglycerol (DAG) biosynthesis through microbiota modulation. Notably, diacylglycerol kinase ζ (DGKζ) inhibitors enhance CD8+ T cell responses by increasing DAG levels, thereby activating Mitogen-Activated Protein Kinase (MAPK) and Protein Kinase C (PKC) signaling pathways. Collectively, our findings suggest that microbiota-derived DAG plays a key role in BRT-mediated enhancement of anti-tumor immunity.

Maternal immunization is an important tool directed against a variety of infectious maladies in the offspring. A complementary, but less explored area is the use of maternal immunization in the prevention and treatment of childhood cancers. This in part stems from the lack of adequate experimental model systems. Lymphomas of the Central Nervous System (CNS) and ocular involvement pose a therapeutic challenge. Ocular lymphoma is a lethal disease caused mainly by two clinically distinct forms of non-Hodgkin's lymphoma: non-Hodgkin's lymphoma of the central nervous system, or Primary CNS lymphoma (PCNSL), and systemic lymphoma metastatic to the eye. Previously, we developed an experimental model whereby mouse lymphoma cell variants, derived from the S49 T-cell lymphoma, metastasized to the CNS and eyes following Intraperitoneal inoculation at days 7-10 postnatal. Here, we extended the model to study whether maternal immunization can impede CNS/Ocular metastasis in the offspring exposed to the metastatic lymphoma cells. To that effect, female Balb/C mice were vaccinated with either immunogenic, live, S49 lymphoma cell variants, or with a purified protein antigen: the 98 amino acid signal peptide of the envelop precursor protein of Mouse Mammary Tumor Virus (MMTV) endogenously harbored by the S49 lymphoma. The offspring from both vaccination protocols were immunized against a challenge with the CNS/Ocular metastatic lymphoma cells. Immunity was conferred via milk suckling and was prolonged without further challenge for an extended period of at least 3 months. The abovementioned findings constitute a novel experimental model system whereby CNS/Ocular metastasis of malignant lymphoma in the offspring is impeded through maternal vaccination/immunization and thus, can be followed mechanistically as well as for novel therapeutic modalities.