Citations

Abstract The DNA damage response (DDR) and the blood tumor barrier (BTB) restrict chemotherapeutic success for primary brain tumors like glioblastoma (GBM). Coherently, GBM almost invariably relapse with fatal outcome. We here show that interaction of GBM and myeloid cells simultaneously induces chemoresistance on the genetic and the vascular level by activating GP130 receptor signaling, which can be addressed therapeutically. We performed transcriptomic and immunohistochemical screens with human brain material, pharmacological experiments with a humanized organotypic GBM model, proteomics and cell-based assays and observed that nanomolar concentrations of the signaling peptide Humanin promoted TMZ resistance through DDR activation. GBM mouse models recapitulating intratumoral Humanin-release showed accelerated BTB formation. Genetic analysis of pericyte to endothelial cell signaling in transgenic mice revealed increased GP130 activation in Humanin releasing tumors as compared to controls. GP130 blockade attenuated both DDR activity and BTB formation resulting in improved preclinical chemotherapeutic efficacy. Altogether, we describe an overarching mechanism for TMZ resistance and outline a translatable strategy with predictive markers to improve chemotherapy for GBM.

Abstract Lymphopenia following chemoradiation for high grade gliomas (HGG) is common and is associated with decreased survival. NT-I7 (efineptakin alfa) is a long-acting analog of the lymphocyte pro-survival cytokine, interleukin-7. Our Phase I dose-escalation study of 19 patients with HGG demonstrated early elevations in CD4+ and CD8+ T cells in the first 4 weeks after administration of NT-I7. In this study, we explored the diversity and potential functionality of the NT-I7-expanded T cell population. A subset of 4 subjects with glioblastoma multiforme (GBM) treated at 720 µg/kg of NT-I7 during adjuvant temozolomide in our study (NCT03687957) underwent Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-seq) of peripheral blood. CITE-seq with TCR clonotype sequencing (10x Genomics 5’) permitted simultaneous tracking of the T cell phenotype at the protein level, individual T cell clones, and gene expression dynamics between 4 timepoints: pre-treatment, and post-treatment weeks 1, 2, and 13. Here, we report the results of differential expression analyses between timepoints and patient-specific differences in T cell clonotype expansions. Both CD4+ and CD8+ T cells in our study patients had increased expression of T cell activation markers LTB, CISH, and CD74. CD8+ T cell subsets demonstrated additional elevations in genes important in cytotoxic function (granzymes (GZMA, GZMB) and perforin (PRF1)), MHC Class II expression (HLA-DRA, HLA-DRB1), and AP-1 transcription factor subunits (JUND, JUN, JUNB, FOS, FOSB). After excluding known viral antigen clonotypes, 2 of 4 patients demonstrated TCR clonotype expansion. Notably, nearly all the expanded TCR clonotypes were found within CD8+ T cells, but not CD4+ T cells. NT-I7 promotes activation, cytotoxic function, and selective clonotype expansion of CD8+ T cells in patients with HGG. This, combined with its role in increased CD4+ T cell counts, suggests NT-I7 may be a powerful tool to restore immune function after treatment-associated lymphopenia in HGG.

Abstract BACKGROUND Brain metastases (BMs) are a significant cause of morbidity and mortality in metastatic breast cancer (MBC), yet prognostic and predictive biomarkers remain poorly understood. STUDY DESIGN 90 consecutive patients with breast cancer BMs who underwent surgical resection from 2006-2022 were retrospectively identified. Review of the electronic medical record and institutional cancer registry were completed to identify baseline clinical parameters and outcomes. BM mutation analysis was performed using a CLIA-certified targeted DNA mutation sequencing assay as part of routine clinical care. RESULTS All patients were female, median age at first BM resection was 57.9 years (range 27.0-81.3 years), and receptor subtypes included HR+/HER2- (n=27, 30.0%), HER2+ (n=33, 36.7%), and triple negative BC (TNBC; n=30, 33.3%). At time of first BM resection, most patients had a solitary BM (n=55, 61.1%), with anatomic locations including cerebellar (n=29, 32.2%), frontal (n=26, 28.9%), and parietal (n=17, 18.9%) sites. BM DNA mutation analysis (n= 20) revealed pathogenic alterations in TP53 (n=17, 85.0%), ERBB2 amplification (n=7, 35.0%), PIK3CA (n=4, 20.0%), BRCA1 (n=3, 15.0%), and BRCA2 (n=2, 10.0%). Most patients received postoperative radiation (n=82, 90.8%) and/or systemic therapy (n=67, 82.7%). Cerebellar location was significantly associated with the risk of developing leptomeningeal disease compared to other BM resection sites (HR = 2.75, p=0.02). Among all patients, median overall survival (OS) from first BM resection was 27.8 months (range 0.1-196.6 months). HR+/HER2- (median 37 months) or HER2+ (median 36 months) MBC was associated with significantly increased OS compared to TNBC (14.4 months) (p<0.01, log-rank test). CONCLUSIONS Patients with breast cancer BMs exhibited a median OS of >2 years following BM resection, and patients with TNBC had a significantly worse prognosis. Targetable mutations were observed in 40% of resected BM specimens, supporting the utility of molecular analysis of resected BMs to help guide clinical management.

ABSTRACT Background The sterol regulatory element‐binding protein (SREBP) pathway is essential for maintaining sterol homeostasis during B cell activation and germinal center B cell proliferation. However, its potential as a therapeutic target to treat B‐cell lymphoma remains unclear. Methods We examined SREBP protein expression in human B‐cell lymphoma samples using immunohistochemistry. Additionally, we conducted in vitro studies using SREBP signaling inhibitors in combination with rapamycin to assess their effects on cell proliferation and lipid metabolism in B‐cell lymphoma cells. Results Our analysis revealed high levels of SREBP2 protein expression in human B‐cell lymphoma samples. Inhibiting SREBP signaling or its downstream target HMG‐CoA reductase (HMGCR) with Fatostatin or Simvastatin effectively suppressed B‐cell lymphoma cell proliferation. However, B‐cell lymphoma cells responded to statin treatment by activating the mTORC1‐pS6 pathway, suggesting a compensatory mechanism to overcome statin‐induced cell cycle arrest. Combining low‐dose statin treatment with the mTOR inhibitor rapamycin produced a synergistic effect, significantly inhibiting B‐cell lymphoma proliferation, cell cycle progression, and lipid raft formation. Conclusions These results highlight the potential of a combined therapeutic approach targeting both SREBP and mTORC1 as a novel strategy for treating B‐cell lymphoma.