Citations

Abstract Description Many cancers, including glioblastoma (GBM), exhibit a male-biased incidence and outcome disparity, partially driven by sex hormones. While androgens are known to suppress anti-tumor T cell immunity in certain solid tumors, we found that androgens instead enhance anti-tumor immunity in brain tumors. Upon castration, tumor growth was accelerated in brain tumor models, while the opposite effect was observed for tumors located outside the brain. Decreased T cell function was observed in both tumors and peripheral lymphoid organs in castrated mice, indicated by reduced anti-tumor cytokines and increased T cell exhaustion. Mechanistically, this systemic immunosuppression was driven by hyperactivation of the hypothalamus-pituitary-adrenal (HPA) axis in castrated mice with brain tumors. Blocking glucocorticoid receptors reversed the accelerated tumor growth in these mice, confirming the role of HPA axis dysregulation. This mechanism was brain-specific rather than GBM-specific, as hyperactivation of the HPA axis was also observed with intracranial implantation of non-GBM tumors. Furthermore, elevated production of proinflammatory cytokines (IL-1β, TNF) in the brain of castrated mice was identified as a driver of HPA axis activation. Taken together, these findings reveal unique endocrine-mediated mechanisms by which brain tumor modulate systemic immunity in the androgen-deprived setting and highlight the importance of organ-specific effects of anti-tumor immunity. Funding Sources NIH P01CA245705; NIH R35NS127083; American Brain Tumor Association; Cleveland Clinic; Case comprehensive cancer center Topic Categories Tumor Immunology: Cellular Responses and Tumor Microevironment (TIME)

Abstract BACKGROUND Gaseous hydrogen sulfide (H2S), a by-product of cysteine metabolism, inhibits cancer cell behavior and growth in glioblastoma (GBM) models. H2S production capacity (HPC) is decreased in human GBM specimens compared to non-tumor controls. Thus, boosting HPC is a novel strategy for GBM treatment. Suppression of thyroid hormone signaling increases production of H2S. Hypothesis: methimazole-induced hypothyroidism will increase tumor HPC to enhance chemotherapy efficacy in GBM. GOAL Proof of concept that methimazole, by reducing thyroid hormone signaling, can increase HPC in patients with recurrent/progressive GBM (rGBM). PRIMARY ENDPOINTS 10% increase in HPC and a 1.5-fold increase in peripheral blood sulfhydration signaling. METHODS This window of opportunity trial evaluates safety, HPC in plasma and tumor, and efficacy of methimazole + chemotherapy in patients with rGBM. rGBM patients planned for a resection begin methimazole 15 mg/d 5-7 days pre-op with investigator’s choice chemotherapy added 10-28 days post-op. Patients receive combination until progression. Pre- and post-op plasma and resected tumor tissue are assayed for HPC and proteins relevant to H2S production. Key eligibility: rGBM for whom a clinically-indicated resection is planned; normal thyroid function with no history of thyroid dysfunction. Patients may have received unlimited prior regimens including bevacizumab. RESULTS To date 15 patients (8 male), median age 56 years, enrolled. The trial was amended to increase methimazole to 25 mg/d; 3 patients have received this dose. Median TSH rose from 1.3 mU/ml to 20.5 at cycle 6. Free T3 and T4 did not fall significantly. Median plasma HPC rose 3-fold while tumor HPC did not rise significantly. No treatment-related grade 3-5 toxicities. Efficacy: PFS6 – 15% and OS12 – 21%. CONCLUSIONS Induction of subclinical hypothyroidism is feasible and safe in rGBM with significant increases in plasma but not tumor HPC. Further tumor correlative data for the dose-escalated methimazole will be presented.

Abstract Sex differences in cancer outcome, including that of glioblastoma (GBM), are shaped by biological, hormonal, and immunological factors and impact disease progression, treatment responses, survival, and tumor microenvironment (TME) interactions. Platelets regulate the immune responses and tumor progression in many cancers, but it is not clear how they contribute to these sex-based differences by affecting the dynamics of the TME. Here, we show that GBM patients exhibit heightened platelet reactivity driven by PAR4 signaling. In murine GBM models, both pharmacological inhibition of PAR4 using BMS986120 and genetic deletion of PAR4 significantly prolong survival in females but not males. This survival advantage is estrogen dependent: it is preserved in chromosomal male-hormonal female mice within the four-core genotype model and is rescued in ovariectomized mice treated with estrogen. The survival benefit is TME specific and is mediated by platelet-driven enhancement of CD8⁺ T cell infiltration into the tumor. Inhibition of platelet PAR4 signaling increases calcium signaling through an estrogen-dependent interaction between PAR4 and estrogen receptor β (ERβ)—a receptor interaction not previously described. PAR4-activated platelets within the TME suppress CD8⁺ T cell function, and depletion of CD8⁺ T cells abolishes both the tumor-induced platelet reactivity and the survival benefit conferred by PAR4 inhibition. These findings establish platelet-mediated PAR4 signaling as a critical driver of tumor progression and identify sex-specific immune responses as key to therapeutic efficacy.

Abstract Many cancers, including glioblastoma (GBM), have a male-biased sex difference in incidence and outcome. The underlying reasons for this sex bias are unclear but likely involve differences in tumor cell state and immune response. This effect is further amplified by sex hormones, including androgens, which have been shown to inhibit anti-tumor T cell immunity. Here, we show that androgens drive anti-tumor immunity in brain tumors, in contrast to its effect in other tumor types. Upon castration, tumor growth was accelerated with attenuated T cell function in GBM and brain tumor models, but the opposite was observed when tumors were located outside the brain. Activity of the hypothalamus-pituitary-adrenal gland (HPA) axis was increased in castrated mice, particularly in those with brain tumors. Blockade of glucocorticoid receptors reversed the accelerated tumor growth in castrated mice, indicating that the effect of castration was mediated by elevated glucocorticoid signaling. Furthermore, this mechanism was not GBM specific, but brain specific, as hyperactivation of the HPA axis was observed with intracranial implantation of non-GBM tumors in the brain. Together, our findings establish that brain tumors drive distinct endocrine-mediated mechanisms in the androgen-deprived setting and highlight the importance of organ-specific effects on anti-tumor immunity.

Ciliated muconodular papillary tumors (CMPTs) are rare peripheral lung lesions, characterized by papillary architecture and ciliated columnar cells admixed with mucinous cells and basal cells. They often have prominent surrounding intra-alveolar mucin, which can lead to diagnostic confusion with mucinous adenocarcinoma. Recognition of the ciliated component is the key to diagnosis of CMPT. The literature contains few reported cases to date, all occurring in East-Asian patients. Although follow-up data are limited, CMPT seems to be an indolent tumor with very good prognosis, leading some to question whether it is a reactive or hamartomatous lesion. However, a very recent molecular study has identified BRAF (40%) and EGFR (30%) alterations in CMPT, supporting a truly neoplastic process. Here for the first time, we report 4 cases of morphologically typical CMPT in western patients, occurring in 1 man (60 y) and 3 women (71 to 83 y). Interestingly, 1 case occurred in background of pronounced small airway disease with necrotizing bronchiolitis and multiple carcinoid tumorlets. We further analyzed 1 tumor using a 50 gene next-generation sequencing oncology panel that identified 2 pathogenic mutations (BRAF V600E and AKT1 E17K). Our study is the first to describe that CMPT can occur in western (non-Asian) patients. Our data confirm BRAF V600E mutation as a probable driver in a subset of these tumors, along with AKT1 mutation, which further supports that CMPT are indolent pulmonary neoplasms.