Cancer Cell

Neutrophil extracellular traps promote pre-metastatic niche formation in the omentum by expanding innate-like B cells that express IL-10

Disseminated cancer cells in the peritoneal fluid often colonize omental fat-associated lymphoid clusters but the mechanisms are unclear. Here, we identify that innate-like B cells accumulate in the omentum of mice and women with early-stage ovarian cancer concomitantly with the extrusion of chromatin fibers by neutrophils called neutrophil extracellular traps (NETs). Studies using genetically modified NET-deficient mice, pharmacologic inhibition of NETs, and adoptive B cell transfer show that NETs induce expression of the chemoattractant CXCL13 in the pre-metastatic omentum, stimulating recruitment of peritoneal innate-like B cells that in turn promote expansion of regulatory T cells and omental metastasis through producing interleukin (IL)-10. Ex vivo studies show that NETs elicit IL-10 production in innate-like B cells by inactivating SHP-1, a phosphatase that inhibits B cell activation pathways, and by generating reactive oxygen species. These findings reveal that NETs alter immune cell dynamics in the pre-metastatic omentum, rendering this niche conducive for colonization.

Decoding evolutionary trajectories of ovarian cancer metastasis

The genetic changes during high-grade serous ovarian cancer metastasis have largely remained a mystery. Lahtinen et al. show that ovarian cancer metastasizes along three different evolutionary states that have distinct mutations and signaling pathways, potentially allowing the identification of targeted treatments.

The discrete charm of oncolytic viruses: Toward the finish line

Proteogenomic insights suggest druggable pathways in endometrial carcinoma

We characterized a prospective endometrial carcinoma (EC) cohort containing 138 tumors and 20 enriched normal tissues using 10 different omics platforms. Targeted quantitation of two peptides can predict antigen processing and presentation machinery activity, and may inform patient selection for immunotherapy. Association analysis between MYC activity and metformin treatment in both patients and cell lines suggests a potential role for metformin treatment in non-diabetic patients with elevated MYC activity. PIK3R1 in-frame indels are associated with elevated AKT phosphorylation and increased sensitivity to AKT inhibitors. CTNNB1 hotspot mutations are concentrated near phosphorylation sites mediating pS45-induced degradation of β-catenin, which may render Wnt-FZD antagonists ineffective. Deep learning accurately predicts EC subtypes and mutations from histopathology images, which may be useful for rapid diagnosis. Overall, this study identified molecular and imaging markers that can be further investigated to guide patient stratification for more precise treatment of EC.

Opening a Door to PARP Inhibitor-Induced Lethality in HR-Proficient Human Tumor Cells

PARP inhibition (PARPi) kills tumor cells defective in homologous recombination-based repair (HR-) but not their HR+ competent counterparts. In this issue of Cancer Cell, it is shown that, when EZH2 is functionally silenced, HR+, CARM1-high, high-grade serous ovarian cancer cells become PARPi sensitive, undergo mitotic catastrophe, and die.

EZH2 Inhibition Sensitizes CARM1-High, Homologous Recombination Proficient Ovarian Cancers to PARP Inhibition

In response to DNA double-strand breaks, MAD2L2-containing shieldin complex plays a critical role in the choice between homologous recombination (HR) and non-homologous end-joining (NHEJ)-mediated repair. Here we show that EZH2 inhibition upregulates MAD2L2 and sensitizes HR-proficient epithelial ovarian cancer (EOC) to poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor in a CARM1-dependent manner. CARM1 promotes MAD2L2 silencing by driving the switch from the SWI/SNF complex to EZH2 through methylating the BAF155 subunit of the SWI/SNF complex on the MAD2L2 promoter. EZH2 inhibition upregulates MAD2L2 to decrease DNA end resection, which increases NHEJ and chromosomal abnormalities, ultimately causing mitotic catastrophe in PARP inhibitor treated HR-proficient cells. Significantly, EZH2 inhibitor sensitizes CARM1-high, but not CARM-low, EOCs to PARP inhibitors in both orthotopic and patient-derived xenografts.

Rejuvenating dysfunctional T cells in ovarian cancer: CD28 is the license to kill

High-grade serous ovarian cancers (HGSOCs) exhibit limited response to immune checkpoint blockade. In a new study in Cancer Cell, Duraiswamy et al. highlight intratumoral CD28 co-stimulation by myeloid-antigen-presenting cells as a key mechanism required for activation of programmed cell death receptor 1 (PD-1)

Evolutionary states and trajectories characterized by distinct pathways stratify patients with ovarian high grade serous carcinoma

Ovarian high-grade serous carcinoma (HGSC) is typically diagnosed at an advanced stage, with multiple genetically heterogeneous clones existing in the tumors long before therapeutic intervention. Herein we integrate clonal composition and topology using whole-genome sequencing data from 510 samples of 148 patients with HGSC in the prospective, longitudinal, multiregion DECIDER study. Our results reveal three evolutionary states, which have distinct features in genomics, pathways, and morphological phenotypes, and significant association with treatment response. Nested pathway analysis suggests two evolutionary trajectories between the states. Experiments with five tumor organoids and three PI3K inhibitors support targeting tumors with enriched PI3K/AKT pathway with alpelisib. Heterogeneity analysis of samples from multiple anatomical sites shows that site-of-origin samples have 70% more unique clones than metastatic tumors or ascites. In conclusion, these analysis and visualization methods enable integrative tumor evolution analysis to identify patient subtypes using data from longitudinal, multiregion cohorts.

Finding the right friends: Stromal composition influences TLS formation in ovarian cancer

In this issue of Cancer Cell, MacFawn et al. reveal that tertiary lymphoid structures (TLSs) in high-grade serous ovarian cancer (HGSOC) vary significantly by anatomical site. They highlight a distinct stromal composition associated with TLS formation, with cancer-educated mesenchymal stem cells (CA-MSCs) inversely linked to TLS activity and patient prognosis.

Immune memory shapes ovarian cancer recurrence

Despite current progress, many patients with ovarian cancer (OC) often relapse after therapy. In this issue of Cancer Cell, Ghisoni et al. integrate multiomic and functional analyses to provide a roadmap for biomarker-driven therapy in OC and suggest that immune phenotyping could be incorporated into clinical stratification.

Spatial proteo-transcriptomic profiling reveals the molecular landscape of borderline ovarian tumors and their invasive progression

Epithelial serous borderline tumors (SBT) are non-invasive neoplastic ovarian lesions that may recur as chemo-resistant low-grade serous cancer (LGSC). While genetic alterations suggest a common origin, the transition from SBT to LGSC remains poorly understood. Here, we integrate cell-type resolved spatial proteomics and transcriptomics to elucidate the evolution from SBT to LGSC and its corresponding metastases in both stroma and tumor. The transition occurs within the epithelial compartment through an intermediary stage with micropapillary features, during which LGSC overexpresses c-Met and several brain-specific proteins. Within the tumor microenvironment, interconnectivity between cancer and stromal cells, along with enzymes degrading a packed extracellular matrix, suggests functional collaboration among various cell types. We functionally validated 16 drug targets identified through integrated spatial transcriptomics and proteomics. Combined treatment targeting CDK4/6 (milciclib) and FOLR1 (mirvetuximab) achieved significant tumor reduction in vivo, representing a promising therapeutic strategy for LGSC.

Chemotherapy induces myeloid-driven spatially confined T cell exhaustion in ovarian cancer

Anti-tumor immunity is crucial for high-grade serous ovarian cancer (HGSC) prognosis, yet its adaptation upon standard chemotherapy remains poorly understood. Here, we conduct spatial and molecular characterization of 117 HGSC samples collected before and after chemotherapy. Our single-cell and spatial analyses reveal increasingly versatile immune cell states forming spatiotemporally dynamic microcommunities. We describe Myelonets, networks of interconnected myeloid cells that contribute to CD8

The activity of tertiary lymphoid structures in high grade serous ovarian cancer is governed by site, stroma, and cellular interactions

Most high grade serous ovarian cancers (HGSOC) originate in the fallopian tube but spread to the ovary and peritoneal cavity, highlighting the need to understand antitumor immunity across HGSOC sites. Using spatial analyses, we discover that tertiary lymphoid structures (TLSs) within ovarian tumors are less developed compared with TLSs in fallopian tube or omental tumors. We reveal transcriptional differences across a spectrum of lymphoid structures, demonstrating that immune cell activity increases when residing in more developed TLSs and produce a prognostic, spatially derived TLS signature from HGSOC tumors. We interrogate TLS-adjacent stroma and assess how normal mesenchymal stem cells MSCs (nMSCs) may support B cell function and TLS, contrary to cancer-educated MSCs (CA-MSCs) which negate the prognostic benefit of our TLS signature, suggesting that pro-tumorigenic stroma could limit TLS formation.

Armored macrophage-targeted CAR-T cells reset and reprogram the tumor microenvironment and control metastatic cancer growth

Tumor-associated macrophages (TAMs), which commonly express FOLR2 or TREM2, are enriched in solid tumors and keep the tumor microenvironment (TME) immunosuppressed. Here, we introduce IL-12-expressing CAR-T cells targeting FOLR2 or TREM2 to deplete pro-tumor TAMs and reprogram the TME. Treatment with IL-12-armored anti-TAM CAR-T leads to significantly improved survival in metastatic ovarian and lung cancer models. The CAR-T mediates benefit at low cell dose and without lymphodepletion, and remains largely restricted to tumors with no overt toxicity. Spatial transcriptomics reveals that IL-12 anti-TAM CAR-T mediates sustained remodeling of the TME, even after CAR-T contraction, with the expansion of CXCL9+ immunostimulatory macrophages and endogenous tumor-specific cytotoxic T cells. Tumor clearance depends, in part, on FAS expression on cancer cells, revealing an IL-12-FAS axis for IL-12-armored CAR-T activity. These findings position IL-12-producing, myeloid-directed CAR-T as a broad strategy to remodel the TME and drive anti-tumor immunity for solid cancers.

Tumor-resident Lactobacillus iners confer chemoradiation resistance through lactate-induced metabolic rewiring

Tumor microbiota can produce active metabolites that affect cancer and immune cell signaling, metabolism, and proliferation. Here, we explore tumor and gut microbiome features that affect chemoradiation response in patients with cervical cancer using a combined approach of deep microbiome sequencing, targeted bacterial culture, and in vitro assays. We identify that an obligate L-lactate-producing lactic acid bacterium found in tumors, Lactobacillus iners, is associated with decreased survival in patients, induces chemotherapy and radiation resistance in cervical cancer cells, and leads to metabolic rewiring, or alterations in multiple metabolic pathways, in tumors. Genomically similar L-lactate-producing lactic acid bacteria commensal to other body sites are also significantly associated with survival in colorectal, lung, head and neck, and skin cancers. Our findings demonstrate that lactic acid bacteria in the tumor microenvironment can alter tumor metabolism and lactate signaling pathways, causing therapeutic resistance. Lactic acid bacteria could be promising therapeutic targets across cancer types.

Myeloid cell networks govern re-establishment of original immune landscapes in recurrent ovarian cancer

Immunotherapy has shown limited success in recurrent ovarian cancer (OC), with prognostic insights largely derived from treatment-naive tumors. We analyzed 697 tumor samples (566 primary and 131 recurrent) from 595 OC patients across five independent cohorts, capturing tumor-infiltrating lymphocytes (TILs) heterogeneity and identifying four immune phenotypes linked to prognosis and TIL:myeloid networks driving malignant progression. We found that in preclinical mouse models, mirroring inflamed human OCs, the recurrent Brca1

Targeting the mevalonate pathway suppresses ARID1A-inactivated cancers by promoting pyroptosis

ARID1A, encoding a subunit of the SWI/SNF complex, is mutated in ∼50% of clear cell ovarian carcinoma (OCCC) cases. Here we show that inhibition of the mevalonate pathway synergizes with immune checkpoint blockade (ICB) by driving inflammasome-regulated immunomodulating pyroptosis in ARID1A-inactivated OCCCs. SWI/SNF inactivation downregulates the rate-limiting enzymes in the mevalonate pathway such as HMGCR and HMGCS1, which creates a dependence on the residual activity of the pathway in ARID1A-inactivated cells. Inhibitors of the mevalonate pathway such as simvastatin suppresses the growth of ARID1A mutant, but not wild-type, OCCCs. In addition, simvastatin synergizes with anti-PD-L1 antibody in a genetic OCCC mouse model driven by conditional Arid1a inactivation and in a humanized immunocompetent ARID1A mutant patient-derived OCCC mouse model. Our data indicate that inhibition of the mevalonate pathway simultaneously suppresses tumor cell growth and boosts antitumor immunity by promoting pyroptosis, which synergizes with ICB in suppressing ARID1A-mutated cancers.

The Repertoire of Serous Ovarian Cancer Non-genetic Heterogeneity Revealed by Single-Cell Sequencing of Normal Fallopian Tube Epithelial Cells

The inter-differentiation between cell states promotes cancer cell survival under stress and fosters non-genetic heterogeneity (NGH). NGH is, therefore, a surrogate of tumor resilience but its quantification is confounded by genetic heterogeneity. Here we show that NGH in serous ovarian cancer (SOC) can be accurately measured when informed by the molecular signatures of the normal fallopian tube epithelium (FTE) cells, the cells of origin of SOC. Surveying the transcriptomes of ∼6,000 FTE cells, predominantly from non-ovarian cancer patients, identified 6 FTE subtypes. We used subtype signatures to deconvolute SOC expression data and found substantial intra-tumor NGH. Importantly, NGH-based stratification of ∼1,700 tumors robustly correlated with survival. Our findings lay the foundation for accurate prognostic and therapeutic stratification of SOC.

Tissue residency of memory CD8+ T cells matters in shaping immunogenicity of ovarian cancer

In this issue of Cancer Cell, Anadon et al. perform a multi-omics analysis of ovarian tumor infiltrating tissue-resident memory T (TRM) cells at the single-cell level that supports a differentiation model from CD103

Ovarian cancer metastasis: Looking beyond the surface

Historically, ovarian cancer (OC) was thought to metastasize by surface-to-surface spread, but recent developments have yielded a new understanding of the paths of metastatic spread. Given the histologic and molecular heterogeneity of OC, we will focus on high-grade serous carcinoma (HGSC). Here, we provide a critical and more holistic view of the evidence supporting various routes of metastasis, including peritoneal, hematogenous, lymphatic, and nerve-related. Understanding the underlying mechanisms is necessary to improve treatment strategies for this challenging disease.

Benchmarking mismatch repair testing for patients with cancer receiving immunotherapy

Immunohistochemistry (IHC) is currently the first-line test for mismatch repair deficiency (MMR-D). Bou Farhat et al. show that mismatch repair (MMR) mutation signature by next-generation sequencing is a highly sensitive assay capable of detecting MMR-D cases that are missed in 1% and 5% of patients with MMR-D colorectal cancer (CRC) and endometrial cancer (EC), respectively. Patients with MMR-D tumors missed by IHC have similar clinical outcomes to patients with MMR-D by both IHC and mutation signature.

Integrated Molecular Characterization of Uterine Carcinosarcoma

We performed genomic, epigenomic, transcriptomic, and proteomic characterizations of uterine carcinosarcomas (UCSs). Cohort samples had extensive copy-number alterations and highly recurrent somatic mutations. Frequent mutations were found in TP53, PTEN, PIK3CA, PPP2R1A, FBXW7, and KRAS, similar to endometrioid and serous uterine carcinomas. Transcriptome sequencing identified a strong epithelial-to-mesenchymal transition (EMT) gene signature in a subset of cases that was attributable to epigenetic alterations at microRNA promoters. The range of EMT scores in UCS was the largest among all tumor types studied via The Cancer Genome Atlas. UCSs shared proteomic features with gynecologic carcinomas and sarcomas with intermediate EMT features. Multiple somatic mutations and copy-number alterations in genes that are therapeutic targets were identified.