Neoadjuvant immune checkpoint blockade in women with mismatch repair deficient endometrial cancer: a phase I study.

Neoadjuvant immune checkpoint blockade (ICB) has shown unprecedented activity in mismatch repair deficient (MMRd) colorectal cancers, but its effectiveness in MMRd endometrial cancer (EC) remains unknown. In this investigator-driven, phase I, feasibility study (NCT04262089), 10 women with MMRd EC of any grade, planned for primary surgery, received two cycles of neoadjuvant pembrolizumab (200 mg IV) every three weeks. A pathologic response (primary objective) was observed in 5/10 patients, with 2 patients showing a major pathologic response.

B cells critical for outcome in high grade serous ovarian carcinoma.

Recent work has shown evidence for the prognostic significance of tumor infiltrating B cells (B-TIL) in high grade serous ovarian carcinoma (HGSOC), the predominant histological subtype of ovarian cancer. However, it remains unknown how the favorable prognosis associated with B-TIL relates to the current standard treatments of primary debulking surgery (PDS) followed by chemotherapy or (neo-)adjuvant chemotherapy (NACT) combined with interval debulking surgery. To address this, we analyzed the prognostic impact of B-TIL in relationship to primary treatment and tumor infiltrating T cell status in a highly homogenous cohort of HGSOC patients.

Immune predictors of response to immune checkpoint inhibitors in mismatch repair-deficient endometrial cancer.

Background: Patients with mismatch repair-deficient (MMRd) endometrial cancer (EC) can derive great benefit from immune checkpoint inhibitors (ICI). However not all responses and predictors of primary resistance are lacking.

Methods: We compared the immune tumor microenvironment of MMRd EC ICI-responders (Rs) and ICI non-responders (NRs), using spatial multiplexed immune profiling and unsupervised hierarchical clustering analysis.

Development of [Zr]Zr-hCD103.Fab01A and [Ga]Ga-hCD103.Fab01A for PET imaging to noninvasively assess cancer reactive T cell infiltration: Fab-based CD103 immunoPET.

Background: CD103 is an integrin specifically expressed on the surface of cancer-reactive T cells. The number of CD103+ T cells significantly increases during successful immunotherapy and might therefore be an attractive biomarker for noninvasive PET imaging of immunotherapy response. Since the long half-life of antibodies preclude repeat imaging of CD103+ T cell dynamics early in therapy, we therefore here explored PET imaging with CD103 Fab fragments radiolabeled with a longer (Zr) and shorter-lived radionuclide (Ga).

Design, Synthesis, and Biological Evaluation of 2-Hydroxy-4-phenylthiophene-3-carbonitrile as PD-L1 Antagonist and Its Comparison to Available Small Molecular PD-L1 Inhibitors.

In search of a potent small molecular PD-L1 inhibitor, we designed and synthesized a compound based on a 2-hydroxy-4-phenylthiophene-3-carbonitrile moiety. Ligand's performance was tested in vitro and compared side-by-side with a known PD-L1 antagonist with a proven bioactivity BMS1166. Subsequently, we modified both compounds to allow F labeling that could be used for PET imaging.

Development of Zr-anti-CD103 PET imaging for non-invasive assessment of cancer reactive T cell infiltration.

Purpose: CD103, an integrin specifically expressed on the surface of cancer-reactive T cells, is significantly increased during successful immunotherapy across human malignancies. In this study, we describe the generation and zirconium-89 (Zr) radiolabeling of monoclonal antibody (mAb) clones that specifically recognize human CD103 for non-invasive immune positron-emission tomography (PET) imaging of T cell infiltration as potential biomarker for effective anticancer immune responses.

Experimental Design: First, to determine the feasibility of anti-CD103 immuno-PET to visualize CD103-positive cells at physiologically and clinically relevant target densities, we developed an Zr-anti-murine CD103 PET tracer.

Tumor infiltrating CD8/CD103/TIM-3-expressing lymphocytes in epithelial ovarian cancer co-express CXCL13 and associate with improved survival.

Reactivation of tumor infiltrating T lymphocytes (TILs) with immune checkpoint inhibitors or co-stimulators has proven to be an effective anti-cancer strategy for a broad range of malignancies. However, epithelial ovarian cancer (EOC) remains largely refractory to current T cell-targeting immunotherapeutics. Therefore, identification of novel immune checkpoint targets and biomarkers with prognostic value for EOC is warranted.

Expression of CD39 Identifies Activated Intratumoral CD8+ T Cells in Mismatch Repair Deficient Endometrial Cancer.

Identification of human cancer-reactive CD8+ T cells is crucial for the stratification of patients for immunotherapy and determination of immune-therapeutic effects. To date, these T cells have been identified mainly based on cell surface expression of programmed cell death protein 1 (PD-1) or co-expression of CD103 and CD39. A small subset of CD103- CD39+ CD8+ T cells is also present in tumors, but little is known about these T cells.

Association of homozygous variants of STING1 with outcome in human cervical cancer.

DNA-sensing receptor Cyclic GMP-AMP Synthase (cGAS) and its downstream signaling effector STimulator of INterferon Genes (STING) have gained significant interest in the field of tumor immunology, as a dysfunctional cGAS-STING pathway is associated with poor prognosis and worse response to immunotherapy. However, studies so far have not taken into account the polymorphic nature of the STING-encoding STING1 gene. We hypothesized that the presence of allelic variance in STING1 would cause variation between individuals as to their susceptibility to cancer development, cancer progression, and potential response to (immuno)therapy.

Prognostic Integrated Image-Based Immune and Molecular Profiling in Early-Stage Endometrial Cancer.

Optimum risk stratification in early-stage endometrial cancer combines clinicopathologic factors and the molecular endometrial cancer classification defined by The Cancer Genome Atlas (TCGA). It is unclear whether analysis of intratumoral immune infiltrate improves this. We developed a machine-learning, image-based algorithm to quantify density of CD8 and CD103 immune cells in tumor epithelium and stroma in 695 stage I endometrioid endometrial cancers from the PORTEC-1 and -2 trials.

Transcriptional Activity and Stability of CD39+CD103+CD8+ T Cells in Human High-Grade Endometrial Cancer.

Tumor-infiltrating CD8+ T cells (TIL) are of the utmost importance in anti-tumor immunity. CD103 defines tumor-resident memory T cells (T cells) associated with improved survival and response to immune checkpoint blockade (ICB) across human tumors. Co-expression of CD39 and CD103 marks tumor-specific T with enhanced cytolytic potential, suggesting that CD39+CD103+ T could be a suitable biomarker for immunotherapy.

A Transcriptionally Distinct CXCL13CD103CD8 T-cell Population Is Associated with B-cell Recruitment and Neoantigen Load in Human Cancer.

The chemokine CXCL13 mediates recruitment of B cells to tumors and is essential for the formation of tertiary lymphoid structures (TLSs). TLSs are thought to support antitumor immunity and are associated with improved prognosis. However, it remains unknown whether TLSs are formed in response to the general inflammatory character of the tumor microenvironment, or rather, are induced by (neo)antigen-specific adaptive immunity.

CD103+ tumor-infiltrating lymphocytes are tumor-reactive intraepithelial CD8+ T cells associated with prognostic benefit and therapy response in cervical cancer.

Human papilloma virus (HPV)-induced cervical cancer constitutively expresses viral E6/E7 oncoproteins and is an excellent target for T cell-based immunotherapy. However, not all tumor-infiltrating T cells confer equal benefit to patients, with epithelial T cells being superior to stromal T cells. To assess whether the epithelial T cell biomarker CD103 could specifically discriminate the beneficial antitumor T cells, association of CD103 with clinicopathological variables and outcome was analyzed in the TCGA cervical cancer data set (n = 304) and by immunohistochemistry (IHC) in an independent cohort (n = 460).

Mutagenesis of nisin's leader peptide proline strongly modulates export of precursor nisin.

The lantibiotic nisin is produced by Lactococcus lactis as a precursor peptide comprising a 23 amino acid leader peptide and a 34 amino acid post-translationally modifiable core peptide. We previously demonstrated that the conserved FNLD part of the leader is essential for intracellular enzyme-catalyzed introduction of lanthionines in the core peptide and also for transporter-mediated export, whereas other positions are subject to large mutational freedom. We here demonstrate that, in the absence of the extracellular leader peptidase, NisP, export of precursor nisin via the modification and transporter enzymes, NisBTC, is strongly affected by multiple substitutions of the leader residue at position -2, but not by substitution of positions in the vicinity of this site.

Microsatellite instability derived JAK1 frameshift mutations are associated with tumor immune evasion in endometrioid endometrial cancer.

JAK1 frameshift mutations may promote cancer cell immune evasion by impeding upregulation of the antigen presentation pathway in microsatellite unstable endometrial cancers (ECs). This study investigated the JAK1 mutation frequency, its functional implication in immune evasion and its prognostic significance in microsatellite unstable EC. Microsatellite instability and three microsatellite repeats within JAK1 were analyzed in 181 ECs.

Discovery, Production and Modification of Five Novel Lantibiotics Using the Promiscuous Nisin Modification Machinery.

To find the right conditions to isolate natively expressed antimicrobial peptides from a wide range of different microorganisms can be a challenge. Here, we exploited a heterologous expression system to produce and characterize several novel lantibiotics. We identified 54 novel putative class I and class II lantibiotics after inspecting all publicly available prokaryotic genomes using the in-house developed mining tool BAGEL3.

CD103+ intraepithelial T cells in high-grade serous ovarian cancer are phenotypically diverse TCRαβ+ CD8αβ+ T cells that can be targeted for cancer immunotherapy.

CD103+ tumor-infiltrating lymphocytes (TIL) have been linked to specific epithelial infiltration and a prolonged survival in high-grade serous epithelial ovarian cancer (HGSC). However, whether these cells are induced as part of an ongoing anti-HGSC immune response or represent non-specifically expanded resident or mucosal lymphocytes remains largely unknown. In this study, we first confirmed that CD103+ TIL from HGSC were predominantly localized in the cancer epithelium and were strongly correlated with an improved prognosis.

CD103 defines intraepithelial CD8+ PD1+ tumour-infiltrating lymphocytes of prognostic significance in endometrial adenocarcinoma.

Introduction: Intraepithelial CD8+ tumour-infiltrating T-lymphocytes (TIL) are associated with a prolonged survival in endometrial cancer (EC). By contrast, stromal infiltration of CD8+ TIL does not confer prognostic benefit. A single marker to discriminate these populations would therefore be of interest for rapid assessment of the tumour immune contexture, ex vivo analysis of intraepithelial and stromal T-cells on a functional level and/or adoptive T-cell transfer.

Treatment Regimen, Surgical Outcome, and T-cell Differentiation Influence Prognostic Benefit of Tumor-Infiltrating Lymphocytes in High-Grade Serous Ovarian Cancer.

Purpose: Tumor-infiltrating lymphocytes (TIL) are associated with a better prognosis in high-grade serous ovarian cancer (HGSC). However, it is largely unknown how this prognostic benefit of TIL relates to current standard treatment of surgical resection and (neo-)adjuvant chemotherapy. To address this outstanding issue, we compared TIL infiltration in a unique cohort of patients with advanced-stage HGSC primarily treated with either surgery or neoadjuvant chemotherapy.

The major myelin-resident protein PLP is transported to myelin membranes via a transcytotic mechanism: involvement of sulfatide.

Myelin membranes are sheet-like extensions of oligodendrocytes that can be considered membrane domains distinct from the cell's plasma membrane. Consistent with the polarized nature of oligodendrocytes, we demonstrate that transcytotic transport of the major myelin-resident protein proteolipid protein (PLP) is a key element in the mechanism of myelin assembly. Upon biosynthesis, PLP traffics to myelin membranes via syntaxin 3-mediated docking at the apical-surface-like cell body plasma membrane, which is followed by subsequent internalization and transport to the basolateral-surface-like myelin sheet.

Mechanistic aspects of lanthipeptide leaders.

Lanthipeptides are ribosomally synthesized and posttranslationally modified peptides produced by microorganisms. The name lanthipeptide is derived from lanthionine, a thioether-bridged amino acid installed by dedicated modification enzymes. Serines and threonines are dehydrated and subsequently coupled to cysteines, thus forming intramolecular lanthionine rings.

Requirements of the engineered leader peptide of nisin for inducing modification, export, and cleavage.

Nisin A is a pentacyclic peptide antibiotic produced by Lactococcus lactis. The leader peptide of prenisin keeps nisin inactive and has a role in inducing NisB- and NisC-catalyzed modifications of the propeptide and NisT-mediated export. The highly specific NisP cleaves off the leader peptide from fully modified and exported prenisin.