Prognostic significance of FCGR2B expression for the response of DLBCL patients to rituximab or obinutuzumab treatment

Fc gamma receptors promote antibody-induced LILRB4 internalization and immune regulation of monocytic AML

The immune checkpoint leukocyte immunoglobulin-like receptor B4 (LILRB4) is found specifically on the cell surface of acute monocytic leukemia (monocytic AML), an aggressive and common subtype of AML. We have developed a humanized monoclonal IgG1 LILRB4-blocking antibody (h128-3), which improved immune regulation but reduced cell surface expression of LILRB4 in monocytic AML models by 40-60%. Interestingly, most of this effect was neutralized by mutation of the Fc region of the antibody (h128-3/N297A), which prevents interaction with Fc gamma receptors (FcγRs). This suggested that there is FcγR-dependent antigenic modulation underlying h128-3's effects, a mechanism known to alter the function of antibodies targeting B-cell malignancies. We disrupted the Fc-FcγR interaction pharmacologically and with stable CRISPR-Cas9-mediated genetic knockout of FcγRs in monocytic AML cell lines to investigate the role of FcγR-dependent antigenic modulation in the regulation of LILRB4 by h128-3. When FcγRI is inhibited or removed from the surface of monocytic AML cells, h128-3 cannot optimally perform its blocking function, resulting in activation of the LILRB4 inhibitory receptor and leading to a 15-25% decrease in T-cell-mediated cytotoxicity in vitro. In the absence of FcγRI, scaffolding by FcγRIIa allows h128-3 to maintain LILRB4-blocking function. Here we define a FcγR-dependent antigenic modulation mechanism underlying the function of an immunoreceptor blocking antibody for the first time in myeloid malignancy. This research will facilitate the development of safe, precision-targeted antibody therapeutics in myeloid malignancies with greater potency and efficacy.

Molecular mechanism and diagnostic marker investigation of endoplasmic reticulum stress on periodontitis

PURPOSE

The aim of this study was to reveal the biological function of endoplasmic reticulum stress (ERS)-related genes (ERSGs) in periodontitis, and provide potential ERS diagnostic markers for clinical therapy of periodontitis.

METHODS

The differentially expressed ERSGs (DE-ERSGs) were reveled based on periodontitis-related microarray dataset in Gene Expression Omnibus (GEO) database and 295 ERS in previous study, followed by a protein-protein interaction network construction. Then, the subtypes of periodontitis were explored, followed by validation with immune cell infiltration and gene set enrichment. Two machine learning algorithms were used to reveal potential ERS diagnostic markers of periodontitis. The diagnostic effect, target drug and immune correlation of these markers were further evaluated. Finally, a microRNA(miRNA)-gene interaction network was constructed.

RESULTS

A total of 34 DE-ERSGs were revealed between periodontitis samples and control, followed by two subtypes investigated. There was a significant difference of ERS score, immune infiltration and Hallmark enrichment between two subtypes. Then, totally 7 ERS diagnostic markers including FCGR2B, XBP1, EDEM2, ATP2A3, ERLEC1, HYOU1 and YOD1 were explored, and the v the time-dependent ROC analysis showed a reliable result. In addition, a drug-gene network was constructed with 4 up-regulated ERS diagnostic markers and 24 drugs. Finally, based on 32 interactions, 5 diagnostic markers and 20 miRNAs, a miRNA-target network was constructed.

CONCLUSIONS

Up-regulated miR-671-5p might take part in the progression of periodontitis via stimulating the expression of ATP2A3. ERSGs including XBP1 and FCGR2B might be novel diagnostic marker for periodontitis.

Fc gamma receptor IIb in tumor-associated macrophages and dendritic cells drives poor prognosis of recurrent glioblastoma through immune-associated signaling pathways

Background: Among central nervous system tumors, glioblastoma (GBM) is considered to be the most destructive malignancy. Recurrence is one of the most fatal aspects of GBM. However, the driver molecules that trigger GBM recurrence are currently unclear. Methods: The mRNA expression data and clinical information of GBM and normal tissues were collected from the Chinese Glioma Genome Atlas The Cancer Genome Atlas (TCGA), and REpository for Molecular BRAin Neoplasia DaTa (REMBRANDT) cohorts. The DESeq2 R package was used to identify the differentially expressed genes between primary and recurrent GBM. ClueGO, Kyoto Encyclopedia of Genes and Genomes (KEGG), Biological Process in Gene ontology (GO-BP), and the Protein ANalysis THrough Evolutionary Relationships (PANTHER) pathway analyses were performed to explore the enriched signaling pathways in upregulated DEGs in recurrent GBM. A gene list that contained potential oncogenes that showed a significant negative correlation with patient survival from The Cancer Genome Atlas was used to further screen driver candidates for recurrent GBM. Univariate Cox proportional hazards regression analyses were used to investigate the risk score for the mRNA expression of the candidates. Single-cell RNA sequencing (scRNA-Seq) analyses were used to determine the cell type-specific distribution of Fc gamma receptor II b (FcγRIIb) in GBM. Immunohistochemistry (IHC) was used to confirm the FcγRIIb-positive cell populations in primary and paired recurrent GBM. Results: Through DEG analysis and overlap analysis, a total of 10 genes that are upregulated in recurrent GBM were screened. Using validation databases, FcγRIIb was identified from the 10 candidates that may serve as a driver for recurrent GBM. FCGR2B expression, not mutation, further showed a highly negative correlation with the poor prognosis of patients with recurrent GBM. Furthermore, scRNA-Seq analyses revealed that tumor-associated macrophage- and dendritic cell-specific FCGR2B was expressed. Moreover, FcγRIIb also showed a strong positive correlation coefficient with major immune-associated signaling pathways. In clinical specimens, FcγRIIb-positive cell populations were higher in recurrent GBM than in primary GBM. Conclusion: This study provides novel insights into the role of FcγRIIb in recurrent GBM and a promising strategy for treatment as an immune therapeutic target.

Acquired B-cell deficiency secondary to B-cell-depleting therapies

The advantage of the newer biological therapies is that the immunosuppressive effect is targeted, in contrast, to the standard, traditional immunomodulatory agents, which have a more global effect. However, there are unintended targets and consequences, even to these "precise" therapeutics, leading to acquired or secondary immunodeficiencies. Besides depleting specific cellular immune subsets, these biological agents, which include monoclonal antibodies against biologically relevant molecules, often have broader functional immune consequences, which become apparent over time. This review focuses on acquired B-cell immunodeficiency, secondary to the use of B-cell depleting therapeutic agents. Among the many adverse consequences of B-cell depletion is the risk of hypogammaglobulinemia, failure of B-cell recovery, impaired B-cell differentiation, and risk of infections. Factors, which modulate the outcomes of B-cell depleting therapies, include the intrinsic nature of the underlying disease, the concomitant use of other immunomodulatory agents, and the clinical status of the patient and other co-existing morbidities. This article seeks to explore the mechanism of action of B-cell depleting agents, the clinical utility and adverse effects of these therapies, and the relevance of systematic and serial laboratory immune monitoring in identifying patients at risk for developing immunological complications, and who may benefit from early intervention to mitigate the secondary consequences. Though these biological drugs are gaining widespread use, a harmonized approach to immune evaluation pre-and post-treatment has not yet gained traction across multiple clinical specialties, because of which, the true prevalence of these adverse events cannot be determined in the treated population, and a systematic and evidence-based dosing schedule cannot be developed. The aim of this review is to bring these issues into focus, and initiate a multi-specialty, data-driven approach to immune monitoring.

FcγRIIB controls antibody-mediated target cell depletion by ITIM-independent mechanisms

Many therapeutic antibodies deplete target cells and elicit immunotherapy by engaging activating Fc gamma receptors (FcγRs) on host effector cells. These antibodies are negatively regulated by the inhibitory FcγRIIB (CD32B). Dogma suggests inhibition is mediated through the FcγRIIB immunoreceptor tyrosine-based inhibition motif (ITIM), negatively regulating immunoreceptor tyrosine-based activation motif (ITAM)-mediated signaling from activating FcγR. To assess this, we generated experimental models expressing human (h)FcγRIIB on targets or effectors, lacking or retaining ITIM signaling capacity. We demonstrate that signaling through the hFcγRIIB ITIM is dispensable for impairing monoclonal antibody (mAb)-mediated depletion of normal and malignant murine target cells through three therapeutically relevant surface receptors (CD20, CD25, and OX40) affecting immunotherapy. We demonstrate that hFcγRIIB competition with activating FcγRs for antibody Fc, rather than ITIM signaling, is sufficient to impair activating FcγR engagement, inhibiting effector function and immunotherapy.

Relevance of Fc Gamma Receptor Polymorphisms in Cancer Therapy With Monoclonal Antibodies

Therapeutic monoclonal antibodies (mAbs), including immune checkpoint inhibitors (ICIs), are an important breakthrough for the treatment of cancer and have dramatically changed clinical outcomes in a wide variety of tumours. However, clinical response varies among patients receiving mAb-based treatment, so it is necessary to search for predictive biomarkers of response to identify the patients who will derive the greatest therapeutic benefit. The interaction of mAbs with Fc gamma receptors (FcγR) expressed by innate immune cells is essential for antibody-dependent cellular cytotoxicity (ADCC) and this binding is often critical for their in vivo efficacy. FcγRIIa (H131R) and FcγRIIIa (V158F) polymorphisms have been reported to correlate with response to therapeutic mAbs. These polymorphisms play a major role in the affinity of mAb receptors and, therefore, can exert a profound impact on antitumor response in these therapies. Furthermore, recent reports have revealed potential mechanisms of ICIs to modulate myeloid subset composition within the tumour microenvironment through FcγR-binding, optimizing their anti-tumour activity. The purpose of this review is to highlight the clinical contribution of FcγR polymorphisms to predict response to mAbs in cancer patients.

CAR-T Cells Shoot for New Targets: Novel Approaches to Boost Adoptive Cell Therapy for B Cell-Derived Malignancies

Chimeric antigen receptor (CAR)-T cell therapy is undeniably a promising tool in combating various types of hematological malignancies. However, it is not yet optimal and a significant number of patients experience a lack of response or relapse after the treatment. Therapy improvement requires careful analysis of the occurring problems and a deeper understanding of the reasons that stand behind them. In this review, we summarize the recent knowledge about CAR-T products' clinical performance and discuss diversified approaches taken to improve the major shortcomings of this therapy. Especially, we prioritize the challenges faced by CD19 CAR-T cell-based treatment of B cell-derived malignancies and revise the latest insights about mechanisms mediating therapy resistance. Since the loss of CD19 is one of the major obstacles to the success of CAR-T cell therapy, we present antigens that could be alternatively used for the treatment of various types of B cell-derived cancers.