Blocking LAIR1 signaling in immune cells inhibits tumor development

Development of an anti-LAIR1 antibody-drug conjugate for acute myeloid leukemia therapy

Acute myeloid leukemia (AML) is a severe blood cancer with an urgent need for novel therapies for refractory or relapsed patients. Leukocyte-associated immunoglobulin-like receptor 1 (LAIR1), an immune suppressive receptor expressed on immune cells and AML blasts but minimally on hematopoietic stem cells (HSCs), represents a potential therapeutic target. But there has been limited research on therapies targeting LAIR1 for AML and no published reports on LAIR1 antibody-drug conjugate (ADC). We developed LA-057-MMAE, a first-in-class ADC, and evaluated its antitumor potential. LA-057-MMAE demonstrated strong binding to human LAIR1 with an affinity of 3.9 nM, efficient internalization of approximately 70 % within 4 h, and remarkable cytotoxicity against AML cells, with IC50 values of 0.22 nM for MV-4-11, 0.02 nM for U937, and 0.09 nM for HL-60 cells, respectively. In vivo, it achieved complete tumor regression in 100 % of MV-4-11 xenograft mice at 6 mg/kg, extending survival beyond 60 days. Our findings suggest that LA-057-MMAE, as a first-in-class treatment distinct from existing LAIR1 monoclonal therapies, could provide a groundbreaking therapeutic strategy for AML.

A Switch Protein Adapter for Anti-LILRB4 CAR-T Cells

Chimeric antigen receptor-T cell (CAR-T) immunotherapy has shown remarkable results for the treatment of certain hematologic malignancies. A redirection strategy that utilizes clinically relevant CAR-T cells in combination with adapter proteins may be an effective strategy to target other hematologic and solid cancers. We established a fusion antibody-based strategy with flexibility to target multiple tumor types in combination with a novel anti-leukocyte immunoglobulin-like receptor-B 4 (LILRB4) CAR-T cell. Specifically, we engineered switch protein (SwP) adapters containing the LILRB4 extracellular domain fused to either an anti-CD19 or anti-CD20 single-chain variable fragment (scFv). These SwPs were sufficient to stimulate anti-LILRB4 CAR-T cells against SwP-tagged LILRB4-CD19+ and LILRB4-CD20+ cancers in vitro and in vivo. This strategy may allow CAR-T cells to be redirected against a variety of tumor antigens and cancer types and become a valuable approach to expand the impact of cellular immunotherapy.

Is modulation of immune checkpoints on glioblastoma-infiltrating myeloid cells a viable therapeutic strategy?

The field of immunology has traditionally focused on immune checkpoint modulation of adaptive immune cells. However, many malignancies such as glioblastoma are mostly devoid of T cells and rather are enriched with immunosuppressive myeloid cells of the innate immune system. While some immune checkpoint targets are shared between adaptive and innate immunity, myeloid-specific checkpoints could also serve as potential therapeutics. To better understand the impact of immune checkpoint blockade on myeloid cells, we systematically summarize the current literature focusing on the direct immunological effects of PD-L1/PD-1, CD24/Siglec-10, collagen/LAIR-1, CX3CL1/CX3CR1, and CXCL10/CXCR3. By synthesizing the molecular mechanisms and the translational implications, we aim to prioritize agents in this category of therapeutics for glioblastoma.

The Multifaced Role of Collagen in Cancer Development and Progression

Collagen is a crucial protein in the extracellular matrix (ECM) essential for preserving tissue architecture and supporting crucial cellular functions like proliferation and differentiation. There are twenty-eight identified types of collagen, which are further divided into different subgroups. This protein plays a critical role in regulating tissue homeostasis. However, in solid tumors, the balance can be disrupted, due to an abundance of collagen in the tumor microenvironment, which significantly affects tumor growth, cell invasion, and metastasis. It is important to investigate the specific types of collagens in cancer ECM and their distinct roles in tumor progression to comprehend their unique contribution to tumor behavior. The diverse pathophysiological functions of different collagen types in cancers illustrate collagen's dual roles, offering potential therapeutic options and serving as prognostic markers.

Subtype-specific analysis of gene co-expression networks and immune cell profiling reveals high grade serous ovarian cancer subtype linkage to variable immune microenvironment

High-grade serous ovarian cancer (HGSOC) is marked by significant molecular diversity, presenting a major clinical challenge due to its aggressive nature and poor prognosis. This study aims to deepen the understanding of HGSOC by characterizing mRNA subtypes and examining their immune microenvironment (TIME) and its role in disease progression. Using transcriptomic data and an advanced computational pipeline, we investigated four mRNA subtypes: immunoreactive, differentiated, proliferative, and mesenchymal, each associated with distinct gene expression profiles and clinical behaviors. We performed differential expression analysis among mRNA subtypes using DESeq2 and conducted Weighted Gene Co-Expression Network Analysis (WGCNA) to identify co-expressed gene modules related to clinical traits, e.g., age, survival, and subtype classification. Gene Ontology (GO) analysis highlighted key pathways involved in tumor progression and immune evasion. Additionally, we utilized TIMER 2.0 to assess immune cell infiltration across different HGSOC subtypes, providing insights into the interplay between tumor immune microenvironment (TIME). Our findings show that the immunoreactive subtype, particularly the M3 module-associated network, was marked by high immune cell infiltration, including M1 (p < 0.0001) and M2 macrophages (p < 0.01), and Th1 cells (p < 0.01) along with LAIR-1 expression (p = 1.63e-101). The M18 module exhibited strong B cell signatures (p = 6.24e-28), along with significant FCRL5 (adj. p = 3.09e-30) and IRF4 (adj. p = 3.09e-30) coexpression. In contrast, the M5 module was significantly associated with the mesenchymal subtype, along with fibroblasts (p < 0.0001). The proliferative subtype was characterized by M15 module-driven cellular growth and proliferation gene expression signatures, along with significant ovarian stromal cell involvement (p < 0.0001). Our study reveals the complex interplay between mRNA subtypes and suggests genes contributing to molecular subtypes, underscoring the important clinical implications of mRNA subtyping in HGSOC.

Leukemic B cells expression of CD200 and Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1, CD305) in Chronic Lymphocytic Leukemia patients in relation to Treg frequency

BACKGROUND

Chronic lymphocytic leukemia (CLL) is characterized by a wide range of tumor-induced immune alterations. Regulatory T cells (Treg) play a central role in these immune responses. CD200 and Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1, CD305) are inhibitory markers said to be involved in Treg immune response. We aimed to analyze the expression of CD200 and LAIR-1 on leukemic cells and assess their interactions with the Treg frequency to elucidate their role in the CLL course.

SUBJECTS AND METHODS

This study was conducted on 70 participants: 50 newly diagnosed CLL cases classified according to Rai staging system into group 1 (n = 25) patients with stages 0, I, and II, and group 2 (n = 25) of advanced patients with stages III and IV. In addition to control group (n = 20) of healthy adults. Flow cytometry was used to investigate Treg frequency in bone marrow (BM) proportional to CD4+ T cell and to assess leukemic cell expression of CD200 and LAIR-1. Also, in-silico database analysis was performed to identify study markers interactions for future personalized target therapy.

RESULTS

Comparison between CLL groups 1 and 2 revealed increased leukemic cell percentage expressing LAIR-1 (p = 0.021) in group 1. Group 2 showed significant increase in frequency of Treg in BM and leukemic cells expressing CD200. There was a strong positive correlation between frequency of Treg and leukemic cells expressing CD200 (r = 0.669, p = 0.000). On the other hand, there was a negative correlation between frequency of Treg and leukemic cell expressing LAIR-1 (r = -0.342, p = 0.015). ROC curve analysis revealed that increased frequency of leukemic cells expressing CD200 yielded sensitivity (SN) and specificity (SP) of 96 % and 84 %, respectively in detecting CLL progression, with an AUC of 0.965. Leukemic cell percentages expressing LAIR-1 yielded a lower SN (75 %), SP (72 %), with an AUC of 0.688.

CONCLUSION

Treg frequency in BM was significantly increased in CLL advanced stages according to Rai classification. Leukemic cells CD200 and LAIR-1 expression were differently associated with Treg frequency. Increased CD200 expressions on leukemic cells can be considered a sensitive and specific biomarker in detecting CLL progression. As demonstrated by the in-silico research, CD200 blockade targeting may offer therapeutic benefits for CLL treatment through Treg suppression.

Leukocyte-associated immunoglobulin-like receptor 1 (LAIR1) is reduced with preeclampsia and small for gestational aged fetuses

Leukocyte-associated immunoglobulin-like receptor 1 (LAIR1) is an inhibitory receptor expressed on immune cells. We evaluated LAIR1 in placentas from preeclamptic or small for gestational age (SGA) pregnancies, and placental explant model (1 % O2, IL6 and TNFα, or control). LAIR1 mRNA was reduced in placentas from preeclamptic (p < 0.0001, n = 78) and SGA (p < 0.0001, n = 32) pregnancies. LAIR1 protein expression was reduced in placentas from preeclampsia (p < 0.0001, n = 43) and SGA (p = 0.009, n = 10) pregnancies. Hypoxia (1 % O2) reduced LAIR1 mRNA expression in placental explants (p = 0.008). These findings suggest hypoxia modulates LAIR1 expression in the placenta.

LAIR1 promotes hepatocellular carcinoma cell metastasis and induces M2-macrophage infiltration through activating AKT-IKKβ-p65 axis

LAIR1, a receptor found on immune cells, is capable of binding to collagen and is involved in immune-related diseases. However, the precise contribution of LAIR1 expressed on hepatocellular carcinoma (HCC) cells to tumor microenvironment is still unclear. In our study, bioinformatics analysis and immunofluorescence were employed to study the correlation between LAIR1 levels and clinical indicators. Transwell and scratch tests were used to evaluate how LAIR1 affected the migration and invasion of HCC cells. The chemotactic capacity and alternative activation of macrophages were investigated using RT-qPCR, transwell, and immunofluorescence. To investigate the molecular mechanisms, transcriptome sequencing analysis, Western blot, nucleus/cytoplasm fractionation, ELISA, and cytokine microarray were employed. We revealed a significant correlation between the presence of LAIR1 and an unfavorable outcome in HCC. We indicated that LAIR1 promoted migration and invasion of HCC cells through the AKT-IKKβ-p65 axis. Additionally, the alternative activation and infiltration of tumor-associated macrophages induced by LAIR1 were reliant on the upregulation of IL6 and CCL5 within this axis, respectively. In conclusion, blocking LAIR1 was found to be an effective approach in combating the cancerous advancement of HCC.

Antitumor Activity of a Novel LAIR1 Antagonist in Combination with Anti-PD1 to Treat Collagen-Rich Solid Tumors

We recently reported that resistance to PD-1 blockade in a refractory lung cancer-derived model involved increased collagen deposition and the collagen-binding inhibitory receptor leukocyte-associated immunoglobulin-like receptor 1 (LAIR1). Thus, we hypothesized that LAIR1 and collagen cooperated to suppress therapeutic response. In this study, we report that LAIR1 is associated with tumor stroma and is highly expressed by intratumoral myeloid cells in both human tumors and mouse models of cancer. Stroma-associated myeloid cells exhibit a suppressive phenotype and correlate with LAIR1 expression in human cancer. NGM438, a novel humanized LAIR1 antagonist mAb, elicits myeloid inflammation and allogeneic T-cell responses by binding to LAIR1 and blocking collagen engagement. Furthermore, a mouse-reactive NGM438 surrogate antibody sensitized refractory KP mouse lung tumors to anti-PD-1 therapy and resulted in increased intratumoral CD8+ T-cell content and inflammatory gene expression. These data place LAIR1 at the intersection of stroma and suppressive myeloid cells and support the notion that blockade of the LAIR1/collagen axis can potentially address resistance to checkpoint inhibitor therapy in the clinic.

Immune checkpoint blockade resistance in lung cancer: emerging mechanisms and therapeutic opportunities

Immune checkpoint blockade (ICB) therapy works by inhibiting suppressive checkpoints that become upregulated after T cell activation, like PD-1/PD-L1 and CTLA-4. While the initial FDA approvals of ICB have revolutionized cancer therapies and fueled a burgeoning immuno-oncology field, more recent clinical development of new agents has been slow. Here, focusing on lung cancer, we review the latest research uncovering tumor cell intrinsic and extrinsic ICB resistance mechanisms as major hurdles to treatment efficacy and clinical progress. These include genomic and non-genomic tumor cell alterations, along with host and microenvironmental factors like the microbiome, metabolite accumulation, and hypoxia. Together, these factors can cooperate to promote immunosuppression and ICB resistance. Opportunities to prevent resistance are constantly evolving in this rapidly expanding field, with the goal of moving toward personalized immunotherapeutic regimens.

Establishment of a novel efferocytosis potential index predicts prognosis and immunotherapy response in cancers

The biological function and prognostic value of efferocytosis in cancer remains unclear. In this study, we systematically analysed the expression profiles and genetic variations of 50 efferocytosis-related regulator genes in 33 cancer types. Using data from The Cancer Genome Atlas, we established an efferocytosis potential index (EPI) model to represent the efferocytosis level in each cancer type. The relationship between the EPI and prognosis, immune-related molecules, specific pathways, and drug sensitivity was determined. We found that efferocytosis regulator genes were abnormally expressed in cancer tissue, perhaps owing to copy number variations, gene alterations, and DNA methylation. For the most part, the EPI was higher in tumour vs. normal tissues. In most of the 33 cancer types, it positively correlated with cell death- and immune-related pathway enrichment, the tumour microenvironment, immune infiltration, and drug sensitivity. For specific cancers, a high EPI may be a prognostic risk factor and, in patients treated receiving immune checkpoint therapy, a predictor of poor prognosis. Our study reveals the biological functions of efferocytosis-related regulator genes in distinct cancers and highlights the potential of efferocytosis intervention in cancer therapy.

A new mechanism of antibody diversity: formation of the natural antibodies containing LAIR1 and LILRB1 extracellular domains

The recent discovery of public antibodies targeting Plasmodium falciparum-encoded repetitive interspersed families of polypeptides (RIFINs), which contain extracellular immunoglobulin-like domains from LAIR1 or LILRB1, constitutes a significant step forward in comprehending the reactivity of the Plasmodium parasite. These antibodies arise from unique B cell clones and demonstrate extensive cross-reactivity through their interaction with P. falciparum RIFINs. LAIR1 and LILRBs are specialized type I transmembrane glycoproteins, classified as immune inhibitory receptors, restricted to primates and mainly found on hematopoietic cells. They are instrumental in modulating interactions within the tumor microenvironment and across the immune system, and are increasingly recognized as important in anti-cancer immunotherapy and pathogen defense. The presence of LAIR1/LILRB1-containing antibodies offers new insights into malaria parasite evasion strategies and the immune system's response. Additionally, the innovative method of integrating extra exons into the antibody switch region is a noteworthy advancement, enriching the strategies for the generation of a varied array of bispecific and multispecific antibodies.

Inhibitory receptors of plasmacytoid dendritic cells as possible targets for checkpoint blockade in cancer

Plasmacytoid dendritic cells (pDCs) are the major producers of type I interferons (IFNs), which are essential to mount antiviral and antitumoral immune responses. To avoid exaggerated levels of type I IFNs, which pave the way to immune dysregulation and autoimmunity, pDC activation is strictly regulated by a variety of inhibitory receptors (IRs). In tumors, pDCs display an exhausted phenotype and correlate with an unfavorable prognosis, which largely depends on the accumulation of immunosuppressive cytokines and oncometabolites. This review explores the hypothesis that tumor microenvironment may reduce the release of type I IFNs also by a more pDC-specific mechanism, namely the engagement of IRs. Literature shows that many cancer types express de novo, or overexpress, IR ligands (such as BST2, PCNA, CAECAM-1 and modified surface carbohydrates) which often represent a strong predictor of poor outcome and metastasis. In line with this, tumor cells expressing ligands engaging IRs such as BDCA-2, ILT7, TIM3 and CD44 block pDC activation, while this blocking is prevented when IR engagement or signaling is inhibited. Based on this evidence, we propose that the regulation of IFN secretion by IRs may be regarded as an "innate checkpoint", reminiscent of the function of "classical" adaptive immune checkpoints, like PD1 expressed in CD8+ T cells, which restrain autoimmunity and immunopathology but favor chronic infections and tumors. However, we also point out that further work is needed to fully unravel the biology of tumor-associated pDCs, the neat contribution of pDC exhaustion in tumor growth following the engagement of IRs, especially those expressed also by other leukocytes, and their therapeutic potential as targets of combined immune checkpoint blockade in cancer immunotherapy.

LILRB3 Supports Immunosuppressive Activity of Myeloid Cells and Tumor Development

The existing T cell-centered immune checkpoint blockade therapies have been successful in treating some but not all patients with cancer. Immunosuppressive myeloid cells, including myeloid-derived suppressor cells (MDSC), that inhibit antitumor immunity and support multiple steps of tumor development are recognized as one of the major obstacles in cancer treatment. Leukocyte Ig-like receptor subfamily B3 (LILRB3), an immune inhibitory receptor containing tyrosine-based inhibitory motifs (ITIM), is expressed solely on myeloid cells. However, it is unknown whether LILRB3 is a critical checkpoint receptor in regulating the activity of immunosuppressive myeloid cells, and whether LILRB3 signaling can be blocked to activate the immune system to treat solid tumors. Here, we report that galectin-4 and galectin-7 induce activation of LILRB3 and that LILRB3 is functionally expressed on immunosuppressive myeloid cells. In some samples from patients with solid cancers, blockade of LILRB3 signaling by an antagonistic antibody inhibited the activity of immunosuppressive myeloid cells. Anti-LILRB3 also impeded tumor development in myeloid-specific LILRB3 transgenic mice through a T cell-dependent manner. LILRB3 blockade may prove to be a novel approach for immunotherapy of solid cancers.

Leukocyte-associated immunoglobulin-like receptor-1 blockade in combination with programmed death-ligand 1 targeting therapy mediates increased tumour control in mice

Collagen expression and structure in the tumour microenvironment are associated with tumour development and therapy response. Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1) is a widely expressed inhibitory collagen receptor. LAIR-2 is a soluble homologue of LAIR-1 that competes for collagen binding. Multiple studies in mice implicate blockade of LAIR-1:collagen interaction in cancer as a promising therapeutic strategy. Here, we investigated the role of LAIR-1 in anti-tumour responses. We show that although LAIR-1 inhibits activation, proliferation, and cytokine production of mouse T cells in vitro, tumour outgrowth in LAIR-1-deficient mice did not differ from wild type mice in several in vivo tumour models. Furthermore, treatment with NC410, a LAIR-2-Fc fusion protein, did not result in increased tumour clearance in tested immunocompetent mice, which contrasts with previous data in humanized mouse models. This discrepancy may be explained by our finding that NC410 blocks human LAIR-1:collagen interaction more effectively than mouse LAIR-1:collagen interaction. Despite the lack of therapeutic impact of NC410 monotherapy, mice treated with a combination of NC410 and anti-programmed death-ligand 1 did show reduced tumour burden and increased survival. Using LAIR-1-deficient mice, we showed that this effect seemed to be dependent on the presence of LAIR-1. Taken together, our data demonstrate that the absence of LAIR-1 signalling alone is not sufficient to control tumour growth in multiple immunocompetent mouse models. However, combined targeting of LAIR-1 and PD-L1 results in increased tumour control. Thus, additional targeting of the LAIR-1:collagen pathway with NC410 is a promising approach to treating tumours where conventional immunotherapy is ineffective.

The entanglement of extracellular matrix molecules and immune checkpoint inhibitors in cancer: a systematic review of the literature

Introduction

Immune-checkpoint inhibitors (ICIs) have emerged as a core pillar of cancer therapy as single agents or in combination regimens both in adults and children. Unfortunately, ICIs provide a long-lasting therapeutic effect in only one third of the patients. Thus, the search for predictive biomarkers of responsiveness to ICIs remains an urgent clinical need. The efficacy of ICIs treatments is strongly affected not only by the specific characteristics of cancer cells and the levels of immune checkpoint ligands, but also by other components of the tumor microenvironment, among which the extracellular matrix (ECM) is emerging as key player. With the aim to comprehensively describe the relation between ECM and ICIs' efficacy in cancer patients, the present review systematically evaluated the current literature regarding ECM remodeling in association with immunotherapeutic approaches.

Methods

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and was registered at the International Prospective Register of Systematic Reviews (PROSPERO, CRD42022351180). PubMed, Web of Science, and Scopus databases were comprehensively searched from inception to January 2023. Titles, abstracts and full text screening was performed to exclude non eligible articles. The risk of bias was assessed using the QUADAS-2 tool.

Results

After employing relevant MeSH and key terms, we identified a total of 5070 studies. Among them, 2540 duplicates, 1521 reviews or commentaries were found and excluded. Following title and abstract screening, the full text was analyzed, and 47 studies meeting the eligibility criteria were retained. The studies included in this systematic review comprehensively recapitulate the latest observations associating changes of the ECM composition following remodeling with the traits of the tumor immune cell infiltration. The present study provides for the first time a broad view of the tight association between ECM molecules and ICIs efficacy in different tumor types, highlighting the importance of ECM-derived proteolytic products as promising liquid biopsy-based biomarkers to predict the efficacy of ICIs.

Conclusion

ECM remodeling has an important impact on the immune traits of different tumor types. Increasing evidence pinpoint at ECM-derived molecules as putative biomarkers to identify the patients that would most likely benefit from ICIs treatments.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022351180, identifier CRD42022351180.

Regulation of tumor immunity and immunotherapy by the tumor collagen extracellular matrix

It has been known for decades that the tumor extracellular matrix (ECM) is dysfunctional leading to loss of tissue architecture and promotion of tumor growth. The altered ECM and tumor fibrogenesis leads to tissue stiffness that act as a physical barrier to immune cell infiltration into the tumor microenvironment (TME). It is becoming increasingly clear that the ECM plays important roles in tumor immune responses. A growing body of data now indicates that ECM components also play a more active role in immune regulation when dysregulated ECM components act as ligands to interact with receptors on immune cells to inhibit immune cell subpopulations in the TME. In addition, immunotherapies such as checkpoint inhibitors that are approved to treat cancer are often hindered by ECM changes. In this review we highlight the ways by which ECM alterations affect and regulate immunity in cancer. More specifically, how collagens and major ECM components, suppress immunity in the complex TME. Finally, we will review how our increased understanding of immune and immunotherapy regulation by the ECM is leading towards novel disruptive strategies to overcome immune suppression.

Proteogenomic landscape of gastric adenocarcinoma peritoneal metastases

Advanced gastric adenocarcinoma (GAC) often leads to peritoneal carcinomatosis (PC) and is associated with very poor outcome. Here we report the comprehensive proteogenomic study of ascites derived cells from a prospective GAC cohort (n = 26 patients with peritoneal carcinomatosis, PC). A total of 16,449 proteins were detected from whole cell extracts (TCEs). Unsupervised hierarchical clustering resulted in three distinct groups that reflected extent of enrichment in tumor cells. Integrated analysis revealed enriched biological pathways and notably, some druggable targets (cancer-testis antigens, kinases, and receptors) that could be exploited to develop effective therapies and/or tumor stratifications. Systematic comparison of expression levels of proteins and mRNAs revealed special expression patterns of key therapeutics target notably high mRNA and low protein expression of HAVCR2 (TIM-3), and low mRNA but high protein expression of cancer-testis antigens CTAGE1 and CTNNA2. These results inform strategies to target GAC vulnerabilities.