Integrative spatial omics reveals distinct tumor-promoting multicellular niches and immunosuppressive mechanisms in African American and European American patients with TNBC.

Racial disparities in triple-negative breast cancer (TNBC) outcomes have been reported. However, the biological mechanisms underlying these disparities remain unclear. We integrated imaging mass cytometry and spatial transcriptomics, to characterize the tumor microenvironment (TME) of African American (AA) and European American (EA) patients with TNBC. The TME in AA patients was characterized by interactions between endothelial cells, macrophages, and mesenchymal-like cells, which were associated with poor patient survival. In contrast, the EA TNBC-associated niche is enriched in T-cells and neutrophils suggestive of an exhaustion and suppression of otherwise active T cell responses. Ligand-receptor and pathway analyses of race-associated niches found AA TNBC to be immune cold and hence immunotherapy resistant tumors, and EA TNBC as inflamed tumors that evolved a distinctive immunosuppressive mechanism. Our study revealed the presence of racially distinct tumor-promoting and immunosuppressive microenvironments in AA and EA patients with TNBC, which may explain the poor clinical outcomes.

5-Hydroxymethylcytosine in Cell-Free DNA Predicts Immunotherapy Response in Lung Cancer.

Immune checkpoint inhibitors (ICIs) drastically improve therapeutic outcomes for lung cancer, but accurately predicting individual patient responses to ICIs remains a challenge. We performed the genome-wide profiling of 5-hydroxymethylcytosine (5hmC) in 85 plasma cell-free DNA (cfDNA) samples from lung cancer patients and developed a 5hmC signature that was significantly associated with progression-free survival (PFS). We built a 5hmC predictive model to quantify the 5hmC level and validated the model in the validation, test, and control sets. Low weighted predictive scores (wp-scores) were significantly associated with a longer PFS compared to high wp-scores in the validation [median 7.6 versus 1.8 months; p = 0.0012; hazard ratio (HR) 0.12; 95% confidence interval (CI), 0.03-0.54] and test (median 14.9 versus 3.3 months; p = 0.00074; HR 0.10; 95% CI, 0.02-0.50) sets. Objective response rates in patients with a low or high wp-score were 75.0% (95% CI, 42.8-94.5%) versus 0.0% (95% CI, 0.0-60.2%) in the validation set (p = 0.019) and 80.0% (95% CI, 44.4-97.5%) versus 0.0% (95% CI, 0.0-36.9%) in the test set (p = 0.0011). The wp-scores were also significantly associated with PFS in patients receiving single-agent ICI treatment (p < 0.05). In addition, the 5hmC predictive signature demonstrated superior predictive capability to tumor programmed death-ligand 1 and specificity to ICI treatment response prediction. Moreover, we identified novel 5hmC-associated genes and signaling pathways integral to ICI treatment response in lung cancer. This study provides proof-of-concept evidence that the cfDNA 5hmC signature is a robust biomarker for predicting ICI treatment response in lung cancer.

Long Interspersed Nuclear Element-1 Analytes in Extracellular Vesicles as Tools for Molecular Diagnostics of Non-Small Cell Lung Cancer.

Aberrant expression of the oncogenic retrotransposon LINE-1 is a hallmark of various cancer types, including non-small cell lung cancers (NSCLCs). Here, we present proof-of-principle evidence that LINE-1 analytes in extracellular vesicles (EVs) serve as tools for molecular diagnostics of NSCLC, with LINE-1 status in tumor cells and tissues mirroring the LINE-1 mRNA and ORF1p cargos of EVs from lung cancer cell culture conditioned media or human plasma. The levels of LINE-1 analytes in plasma EVs from ostensibly healthy individuals were higher in females than males. While the profiles of LINE-1 mRNA and ORF1p in African Americans compared to Hispanics were not significantly different, African Americans showed slightly higher ORF1p content, and 2-3 times greater ranges of LINE-1 values compared to Hispanics. Whole plasma ORF1p levels correlated with EV ORF1p levels, indicating that most of the circulating LINE-1 protein is contained within EVs. EV LINE-1 mRNA levels were elevated in patients with advanced cancer stages and in select patients with squamous cell carcinoma and metastatic tumors compared to adenocarcinomas. The observed EV LINE-1 mRNA profiles paralleled the patterns of ORF1p expression in NSCLC tissue sections suggesting that LINE-1 analytes in plasma EVs may serve to monitor the activity of LINE-1 retroelements in lung cancer.

LILRB3 Modulates Acute Myeloid Leukemia Progression and Acts as an Effective Target for CAR T-cell Therapy.

Identifying novel cell surface receptors that regulate leukemia cell differentiation and can be targeted to inhibit cellular proliferation is crucial to improve current treatment modalities in acute myeloid leukemia (AML), especially for relapsed or chemotherapy-refractory leukemia. Leukocyte immunoglobulin-like receptor type B (LILRB) is an immunomodulatory receptor originally found to be expressed in myeloid cells. In this study, we found that LILRB receptors can be induced under inflammatory stimuli and chemotherapy treatment conditions. Blockade of LILRB3 inhibited leukemia cell proliferation and leukemia progression. In addition, treatment with LILRB3 blocking antibodies upregulated myeloid lineage differentiation transcription factors, including PU.1, C/EBP family, and IRF, whereas phosphorylation of proliferation regulators, for example, AKT, cyclin D1, and retinoblastoma protein, was decreased. Conversely, transcriptomic analysis showed LILRB3 activation by agonist antibodies may enhance leukemia survival through upregulation of cholesterol metabolism, which has been shown to promote leukemia cell survival. Moreover, LILRB3-targeted CAR T cells exhibited potent antitumor effects both in vitro and in vivo. Taken together, our results suggest that LILRB3 is a potentially potent target for multiple treatment modalities in AML. SIGNIFICANCE: LILRB3 regulates differentiation and proliferation in acute myeloid leukemia and can be targeted with monoclonal antibodies and CAR T cells to suppress leukemia growth.