Heath, Elisabeth I

Abstract Purpose: B7-H3 (CD276) represents a promising therapeutic target tested in high-risk localized and treatment-refractory metastatic prostate cancer. To guide therapeutic development and treatment strategies, we examined prostate tumors and evaluated expression, molecular features, and overall survival (OS), accounting for tissue site, hormone sensitivity status, and race. Experimental Design: A total of 8,157 prostate cancer samples with paired DNA/RNA were analyzed based on annotations by tissue site, self-reported race, and disease state: hormone-sensitive prostate cancer (HSPC), castration-resistant prostate cancer (CRPC), or neuroendocrine prostate cancer (NEPC). Expression quartiles were B7-H3–high (>75th percentile) or B7-H3–low (<25th percentile). The OS was evaluated using Kaplan–Meier and Cox proportional hazards models. Results: B7-H3 expression was broadly maintained but varied by tumor site, hormone sensitivity status, and race. High expression aligned with AR-associated transcription factors (HOXB13 and FOXA1), AR-associated pathogenic dysregulations (AR-V7, SPOP, FOXA1, and TMPRSS2:ERG fusions), and actionable surface antigens (TROP2 and NECTIN-4). Weak correlations were found for lineage-plastic program regulators (EZH2, SOX2, and ASCL1) and NEPC-associated surface antigens (DLL3 and CEACAM5). High B7-H3 expression in primary tumors and HSPCs portended adverse OS [hazard ratio (HR), 1.342 and 1.30; confidence interval (CI), 1.19–1.512 and 1.15–1.46; q < 0.0001] although it was favorable in metastatic tumors (HR, 0.823; CI, 0.719–0.942; q = 0.0048). No significant differences in OS were observed among CRPCs and NEPCs, although OS varied by race, with the poorest survival in Asian/Pacific Islander patients with metastatic prostate cancer (HR, 3.72; CI, 1.49–9.29; q = 0.012). Conclusions: Maintained B7-H3 expression in various prostate cancer settings supports its viability as a target. The associations with AR-related molecular factors, surface antigens, and investigative targets for cell therapy or antibody–drug conjugates suggest potential dual-targeting strategies. See related article by Sharma et al., p. 3365

Abstract Natural killer (NK) cells represent key effectors of antitumor immunity, yet emerging evidence highlights populations with distinct roles in cancer. Despite such expanded diversity within the NK cell repertoire, we lack an understanding of how this heterogeneity affects immune responses and downstream clinical outcomes. Using single-cell RNA sequencing, we systematically profiled NK cells across cancer and uncovered a dichotomous phenotypic and functional landscape of tumor-infiltrating NK cells shaped by opposing intrinsic signaling programs that drive the expression of IFNG or TGFB1. These divergent programs are associated with distinct transcription factor circuits that integrate cues within the tumor microenvironment and skew NK cells toward proinflammatory or suppressive functions. We found that the capacity for NK cells to engage in either functional direction is intrinsically linked to their phenotypic identity. Canonical NK cells recruited from circulation predominantly directed suppressive TGFB1 signals toward effector CD8+ T cells in tumors. Of note, these subsets exhibited higher TGFB1 expression than intratumoral myeloid cells across tumor types. In contrast, a tissue-resident (TR) adaptive subset exhibited exclusively proinflammatory IFNG-driven profiles and was associated with prolonged survival in both primary and metastatic tumor settings. Moreover, these TR adaptive NK cells, but not other subsets, were linked to response to immune checkpoint blockade. Collectively, our study reveals a previously unrecognized regulatory axis in NK cells that shapes NK cell diversity and augments broader antitumor immune responses.

Abstract The roles of nucleoplasm-residing nucleoporins (NUP) in solid tumors, including prostate cancer, remain unknown. In this study, we reveal the clinical significance and mechanistic role of the off-pore NUP, soluble POM121 (sPOM121), as a crucial transcriptional regulator that enhances the aggressiveness of metastatic prostate cancer. Using orthogonal methodologies in human samples, sPOM121 was identified as the predominantly expressed nucleoplasmic NUP in prostate cancer. Unbiased proteomic and epigenomic studies demonstrate that sPOM121, through its C-terminus, interacts with the chromatin remodeler SMARCA5 at gene promoter sites and localizes at nuclear condensates, reprogramming gene expression. Indeed, sPOM121 regulates a distinct oncogenic gene network, including β-catenin, leading to prostate cancer progression and immune evasion. Importantly, targeting the sPOM121/β-catenin axis in patient-derived preclinical and syngeneic mouse models halts prostate cancer aggressiveness and enhances antitumor immunity. Taken together, these findings reveal previously unknown actionable reprogramming functions of off-pore NUPs in solid tumors. Significance: This study uncovers how oncogenic signaling programs are transcriptionally heightened by the NUP sPOM121 in metastatic prostate cancer. Localization of sPOM121 at active transcriptional nuclear condensates propels disease progression and immune evasion, offering novel anticancer therapeutic opportunities.

Abstract Purpose: Around 10% to 15% of prostate cancers harbor recurrent aberrations in the Forkhead Box A1 gene, FOXA1, whereby the alteration type and the effect on the forkhead (FKH) domain affect protein function. We developed a FOXA1 classification system to inform clinical management. Experimental Design: A total of 5,014 prostate cancer samples were examined using whole-exome and -transcriptome sequencing from the Caris Life Sciences database. We denoted class 1 FOXA1 alterations as missense and in-frame insertions/deletions with subclasses oriented with respect to the FKH domain. These were in the first part of the FKH domain [class 1A: amino acids (AA) 168–246], within the Wing2 region of FKH (class 1B: AA 247–269), or outside FKH (class 1C: AA 1–167, 270+). Two hotspot missense mutations at R219 were denoted class 2. Class 3 included predicted truncating mutations with subclasses partitioned based on the FKH domain (class 3A: AA 1–269 and class 3B: AA 270+). Class 4 represented FOXA1 amplifications. Real-world overall survival and therapy outcomes were determined from insurance claims. Results: FOXA1 alterations did not influence survival when considered in aggregate but had distinct prognostic effects when stratified by class. In primary prostate samples, class 1A alterations were associated with overall improved survival (HR, 0.57; P = 0.03); a similar trend was seen in metastatic biopsies with class 1B (HR, 0.84; P = 0.09). Conversely, in primary specimens, class 1C exhibited worse survival upon second-generation androgen receptor signaling inhibitor treatment (HR, 1.93; P < 0.001). Class 2 mutations (R219C/S) were enriched in neuroendocrine prostate cancers and were associated with overall poor survival (HR, 2.05; P < 0.001) and worse outcomes to first-line androgen-deprivation therapies (HR, 2.5; P < 0.001). Class 3A alterations indicated improved survival (HR, 0.70; P = 0.01), whereas class 3B alterations portended poor outcomes (HR, 1.50; P < 0.001). Amplifications (class 4) indicated poor outcomes in metastatic samples (HR, 1.48; P = 0.02). Molecularly, different FOXA1 alteration classes harbored distinct mutational and immunologic features as well as unique transcriptional programs. Finally, relative to European Americans, African Americans had increased class 1C alterations, whereas Asian/Pacific Islander patients had increased class 1B alterations. Conclusions: FOXA1 alterations should not be interpreted in aggregate, as different classes are associated with divergent molecular features and clinical outcomes. Our revised classification schema facilitates clinical decision-making for patients with prostate cancer and uncovers important racial differences.

Indications for and implications of germline genetic testing (GGT) in patients with prostate cancer have expanded over the past decade, particularly related to precision therapies and management. GGT has become the standard of care for many cancers such as breast, ovarian, colorectal, pancreatic, and metastatic prostate cancer, and it is imperative that patients be offered timely and equitable access to testing as it can inform patient-physician shared decision making for management of the current cancer as well as anticipatory guidance for disease progression. Additionally, GGT guides screening for and prevention of secondary malignancies for the patient and cascade testing for at-risk family members. Here, we present data supporting the notion that clinicians should offer all patients with prostate cancer the opportunity to undergo comprehensive GGT for pathogenic germline variants known to be associated with familial cancer and/or known to have implications for treatment and management.

Abstract B7-H3 (CD276) is a transmembrane glycoprotein of the B7 immune checkpoint superfamily that has emerged as a promising therapeutic target. To better understand the applicability of B7-H3–directed therapies, we analyzed 156,791 samples comprising 50 cancer types to interrogate the clinical, genomic, transcriptomic, and immunologic correlates of B7-H3 mRNA expression. DNA (592-gene/whole-exome) and RNA (whole-transcriptome) sequencing was performed from samples submitted to Caris Life Sciences. B7-H3 high versus low expression was based on top and bottom quartiles for each cancer type. Patients’ overall survival was determined from insurance claims data. Pathway analysis was performed using gene set enrichment analyses. Immune cell fractions were inferred using quanTIseq. B7-H3 is expressed across several human malignancies including prostate, pancreatic, ovarian, and lung cancers. High B7-H3 expression is associated with differences in overall survival, possibly indicating a prognostic role of B7-H3 for some cancers. When examining molecular features across all cancer types, we did not identify recurrent associations between B7-H3 expression and genetic alterations in TP53, RB1, and KRAS. However, we find consistent enrichment of epithelial-to-mesenchymal transition, Wnt, TGFβ, and Notch signaling pathways. In addition, tumors with high B7-H3 expression are associated with greater proportions of M1 macrophages, but lower fractions of CD8+ T cells. We have begun to define the genomic, transcriptomic, clinical, and immunologic features associated with B7-H3 expression in 50 cancer types. We report novel clinical and molecular features of B7-H3–high tumors which may inform how current B7-H3 therapeutics should be deployed and prioritized. Significance: B7-H3–targeting therapeutics have shown promising results in initial clinical trials. In this pan-cancer analysis of B7-H3 mRNA expression, we found that B7-H3 exhibits robust expression in many common cancer types. These results may inform further development of B7-H3–targeting therapeutics and may guide clinical decisions for patients with limited treatment options.