Molecular Pathways and Mechanisms of LAG3 in Cancer Therapy

A landscape of checkpoint blockade resistance in cancer: underlying mechanisms and current strategies to overcome resistance

The discovery of immune checkpoints and the development of immune checkpoint inhibitors (ICI) have achieved a durable response in advanced-stage cancer patients. However, there is still a high proportion of patients who do not benefit from ICI therapy due to a lack of response when first treated (primary resistance) or detection of disease progression months after objective response is observed (acquired resistance). Here, we review the current FDA-approved ICI for the treatment of certain solid malignancies, evaluate the contrasting responses to checkpoint blockade in different cancer types, explore the known mechanisms associated with checkpoint blockade resistance (CBR), and assess current strategies in the field that seek to overcome these mechanisms. In order to improve current therapies and develop new ones, the immunotherapy field still has an unmet need in identifying other molecules that act as immune checkpoints, and uncovering other mechanisms that promote CBR.

Reversal of T-cell exhaustion: Mechanisms and synergistic approaches

T cells suffer from long-term antigen stimulation and insufficient energy supply, leading to a decline in their effector functions, memory capabilities, and proliferative capacity, ultimately resulting in T cell exhaustion and an inability to perform normal immune functions in the tumor microenvironment. Therefore, exploring how to restore these exhausted T cells to a state with effector functions is of great significance. Exhausted T cells exhibit a spectrum of molecular alterations, such as heightened expression of inhibitory receptors, shifts in transcription factor profiles, and modifications across epigenetic, metabolic, and transcriptional landscapes. This review provides a comprehensive overview of various strategies to reverse T cell exhaustion, including immune checkpoint blockade, and explores the potential synergistic effects of combining multiple approaches to reverse T cell exhaustion. It offers new insights and methods for achieving more durable and effective reversal of T cell exhaustion.

LAG-3 and PD-1 synergize on CD8+ T cells to drive T cell exhaustion and hinder autocrine IFN-γ-dependent anti-tumor immunity

Overcoming immune-mediated resistance to PD-1 blockade remains a major clinical challenge. Enhanced efficacy has been demonstrated in melanoma patients with combined nivolumab (anti-PD-1) and relatlimab (anti-LAG-3) treatment, the first in its class to be FDA approved. However, how these two inhibitory receptors synergize to hinder anti-tumor immunity remains unknown. Here, we show that CD8+ T cells deficient in both PD-1 and LAG-3, in contrast to CD8+ T cells lacking either receptor, mediate enhanced tumor clearance and long-term survival in mouse models of melanoma. PD-1- and LAG-3-deficient CD8+ T cells were transcriptionally distinct, with broad TCR clonality and enrichment of effector-like and interferon-responsive genes, resulting in enhanced IFN-γ release indicative of functionality. LAG-3 and PD-1 combined to drive T cell exhaustion, playing a dominant role in modulating TOX expression. Mechanistically, autocrine, cell-intrinsic IFN-γ signaling was required for PD-1- and LAG-3-deficient CD8+ T cells to enhance anti-tumor immunity, providing insight into how combinatorial targeting of LAG-3 and PD-1 enhances efficacy.

Blockade of LAG-3 and PD-1 leads to co-expression of cytotoxic and exhaustion gene modules in CD8+ T cells to promote antitumor immunity

Relatlimab (rela; anti-LAG-3) plus nivolumab (nivo; anti-PD-1) is safe and effective for treatment of advanced melanoma. We designed a trial (NCT03743766) where advanced melanoma patients received rela, nivo, or rela+nivo to interrogate the immunologic mechanisms of rela+nivo. Analysis of biospecimens from this ongoing trial demonstrated that rela+nivo led to enhanced capacity for CD8+ T cell receptor signaling and altered CD8+ T cell differentiation, leading to heightened cytotoxicity despite the retention of an exhaustion profile. Co-expression of cytotoxic and exhaustion signatures was driven by PRDM1, BATF, ETV7, and TOX. Effector function was upregulated in clonally expanded CD8+ T cells that emerged after rela+nivo. A rela+nivo intratumoral CD8+ T cell signature was associated with a favorable prognosis. This intratumoral rela+nivo signature was validated in peripheral blood as an elevated frequency of CD38+TIM3+CD8+ T cells. Overall, we demonstrated that cytotoxicity can be enhanced despite the retention of exhaustion signatures, which will inform future therapeutic strategies.

Inhibition of USP7 enhances CD8+ T cell activity in liver cancer by suppressing PRDM1-mediated FGL1 upregulation

Lymphocyte activation gene 3 (LAG3), an immune checkpoint molecule expressed on activated T cells, functions as a negative regulator of immune responses. Persistent antigen exposure in the tumor microenvironment results in sustained LAG3 expression on T cells, contributing to T cell dysfunction. Fibrinogen-like protein 1 (FGL1) has been identified as a major ligand of LAG3, and FGL1/LAG3 interaction forms a novel immune checkpoint pathway that results in tumor immune evasion. In addition, ubiquitin-specific peptidase 7 (USP7) plays a crucial role in cancer development. In this study we investigated the role of USP7 in modulation of FGL1-mediated liver cancer immune evasion. We showed that knockdown of USP7 or treatment with USP7 inhibitor P5091 suppressed liver cancer growth by promoting CD8+ T cell activity in Hepa1-6 xenograft mice and in HepG2 or Huh7 cells co-cultured with T cells, whereas USP7 overexpression produced the opposite effect. We found that USP7 upregulated FGL1 in HepG2 and Huh7 cells by deubiquitination of transcriptional factor PR domain zinc finger protein 1 (PRDM1), which transcriptionally activated FGL1, and attenuated the CD8+ T cell activity, leading to the liver cancer growth. Interestingly, USP7 could be transcriptionally stimulated by PRDM1 as well in a positive feedback loop. P5091, an inhibitor of USP7, was able to downregulate FGL1 expression, thus enhancing CD8+ T cell activity. In an immunocompetent liver cancer mouse model, the dual blockade of USP7 and LAG3 resulted in a superior antitumor activity compared with anti-LAG3 therapy alone. We conclude that USP7 diminishes CD8+ T cell activity by a USP7/PRDM1 positive feedback loop on FGL1 production in liver cancer; USP7 might be a promising target for liver cancer immunotherapy.

Spatial Landscape of Malignant Pleural and Peritoneal Mesothelioma Tumor Immune Microenvironments

Immunotherapies have demonstrated limited clinical efficacy in malignant mesothelioma treatment. We conducted multiplex immunofluorescence analyses on tissue microarrays (n = 3) from patients with malignant pleural mesothelioma (MPM, n = 88) and malignant peritoneal mesothelioma (MPeM, n = 25). Our study aimed to elucidate spatial distributions of key immune cell populations and their association with lymphocyte activation gene 3 (LAG3), BRCA1-associated protein 1 (BAP1), neurofibromatosis type 2 (NF2), and methylthioadenosine phosphorylase (MTAP), with MTAP serving as a cyclin-dependent kinase inhibitor 2A/2B (CDKN2A/B) surrogate marker. Additionally, we examined the relationship between the spatial distribution of major immune cell types and prognosis and clinical characteristics of patients with malignant mesothelioma. We observed a higher degree of interaction between immune cells and tumor cells in MPM compared with MPeM. Notably, within MPM tumors, we detected a significantly increased interaction between tumor cells and CD8+ T cells in tumors with low BAP1 expression compared with those with high BAP1 expression. To support the broader research community, we have developed The Human Spatial Atlas of Malignant Mesothelioma, containing hematoxylin and eosin and multiplex immunofluorescence images with corresponding metadata.

SIGNIFICANCE

Considering the limited therapeutic options available to patients with malignant mesothelioma, there is substantial translational potential in understanding the correlation between the spatial architecture of the malignant mesothelioma tumor immune microenvironment and tumor biology. Our investigation reveals critical cell-cell interactions that may influence the immune response against malignant mesothelioma tumors, potentially contributing to the differential behaviors observed in MPM and MPeM. These findings represent a valuable resource for the malignant mesothelioma cancer research community.

ImmunoPET imaging of LAG-3 expression in tumor microenvironment with 68Ga-labelled cyclic peptides tracers: from bench to bedside

BACKGROUND

Lymphocyte activation gene 3 (LAG-3) has been considered as the next generation of immune checkpoint and a promising prognostic biomarker of immunotherapy. As with programmed cell death protein-1/programmed death-ligand 1 and cytotoxic T-lymphocyte antigen-4 inhibitors, positron emission tomography (PET) imaging strategies could benefit the development of clinical decision-making of LAG-3-related therapy. In this study, we developed and validated 68Ga-labeled cyclic peptides tracers for PET imaging of LAG-3 expression in bench-to-bedside studies.

METHODS

A series of LAG-3-targeted cyclic peptides were modified and radiolabeled with 68GaCl3 and evaluated their affinity and specificity, biodistribution, pharmacokinetics, and radiation dosimetry in vitro and in vivo. Furthermore, hu-PBL-SCID (PBL) mice models were constructed to validate the capacity of [68Ga]Ga-CC09-1 for mapping of LAG-3+ lymphocytes infiltrates using longitudinal PET imaging. Lastly, [68Ga]Ga-CC09-1 was translated into the first-in-human studies to assess its safety, biodistribution and potential for imaging of LAG-3 expression.

RESULTS

A series of cyclic peptides targeting LAG-3 were employed as lead compounds to design and develop 68Ga-labeled PET tracers. In vitro binding assays showed higher affinity and specificity of [68Ga]Ga-CC09-1 in Chinese hamster ovary-human LAG-3 cells and peripheral blood mononuclear cells. In vivo PET imaging demonstrated better imaging capacity of [68Ga]Ga-CC09-1 with a higher tumor uptake of 1.35±0.33 per cent injected dose per gram and tumor-to-muscle ratio of 17.18±3.20 at 60 min post-injection. Furthermore, [68Ga]Ga-CC09-1 could detect the LAG-3+ lymphocyte infiltrates in spleen, lung and salivary gland of PBL mice. In patients with melanoma and non-small cell lung cancer, primary lesions with modest tumor uptake were observed in [68Ga]Ga-CC09-1 PET, as compared with that of [18F]FDG PET. More importantly, [68Ga]Ga-CC09-1 delineated the heterogeneity of LAG-3 expression within large tumors.

CONCLUSION

These findings consolidated that [68Ga]Ga-CC09-1 is a promising PET tracer for quantifying the LAG-3 expression in tumor microenvironment, indicating its potential as a companion diagnostic for patients stratification and therapeutic response monitoring in anti-LAG-3 therapy.

Cutting Edge: LAG3 Dimerization Is Required for TCR/CD3 Interaction and Inhibition of Antitumor Immunity

Lymphocyte activation gene 3 (LAG3) is an inhibitory receptor that plays a critical role in controlling T cell tolerance and autoimmunity and is a major immunotherapeutic target. LAG3 is expressed on the cell surface as a homodimer but the functional relevance of this is unknown. In this study, we show that the association between the TCR/CD3 complex and a murine LAG3 mutant that cannot dimerize is perturbed in CD8+ T cells. We also show that LAG3 dimerization is required for optimal inhibitory function in a B16-gp100 tumor model. Finally, we demonstrate that a therapeutic LAG3 Ab, C9B7W, which does not block LAG3 interaction with its cognate ligand MHC class II, disrupts LAG3 dimerization and its association with the TCR/CD3 complex. These studies highlight the functional importance of LAG3 dimerization and offer additional approaches to therapeutically target LAG3.

VISTA: A Novel Checkpoint for Cancer Immunotherapy

V-domain Ig suppressor of T cell activation (VISTA) is a recently identified member of the B7 family of immunoregulatory proteins. It is pivotal for maintaining T cell quiescence and exerts a significant regulatory influence on the immune response to tumors. Accumulating clinical evidence suggests that the influence of VISTA on tumor immunity is more nuanced than initially postulated. Although these revelations add layers of complexity to our understanding of the function of VISTA, they also offer novel avenues for scientific inquiry and potential therapeutic targets. In this review, we scrutinize the current literature pertaining to the expression of VISTA in various of malignancies, aiming to elucidate its intricate roles within the tumor microenvironment and in cancer immunotherapy.

Beyond the Barrier: Unraveling the Mechanisms of Immunotherapy Resistance

Immune checkpoint blockade (ICB) induces a remarkable and durable response in a subset of cancer patients. However, most patients exhibit either primary or acquired resistance to ICB. This resistance arises from a complex interplay of diverse dynamic mechanisms within the tumor microenvironment (TME). These mechanisms include genetic, epigenetic, and metabolic alterations that prevent T cell trafficking to the tumor site, induce immune cell dysfunction, interfere with antigen presentation, drive heightened expression of coinhibitory molecules, and promote tumor survival after immune attack. The TME worsens ICB resistance through the formation of immunosuppressive networks via immune inhibition, regulatory metabolites, and abnormal resource consumption. Finally, patient lifestyle factors, including obesity and microbiome composition, influence ICB resistance. Understanding the heterogeneity of cellular, molecular, and environmental factors contributing to ICB resistance is crucial to develop targeted therapeutic interventions that enhance the clinical response. This comprehensive overview highlights key mechanisms of ICB resistance that may be clinically translatable.

Insights in Molecular Therapies for Hepatocellular Carcinoma

We conducted a comprehensive review of the current literature of published data and clinical trials (MEDLINE), as well as published congress contributions and active recruiting clinical trials on targeted therapies in hepatocellular carcinoma. Combinations of different agents and medical therapy along with radiological interventions were analyzed for the setting of advanced HCC. Those settings were also analyzed in combination with adjuvant situations after resection or radiological treatments. We summarized the current knowledge for each therapeutic setting and combination that currently is or has been under clinical evaluation. We further discuss the results in the background of current treatment guidelines. In addition, we review the pathophysiological mechanisms and pathways for each of these investigated targets and drugs to further elucidate the molecular background and underlying mechanisms of action. Established and recommended targeted treatment options that already exist for patients are considered for systemic treatment: atezolizumab/bevacizumab, durvalumab/tremelimumab, sorafenib, lenvatinib, cabozantinib, regorafenib, and ramucirumab. Combination treatment for systemic treatment and local ablative treatment or transarterial chemoembolization and adjuvant and neoadjuvant treatment strategies are under clinical investigation.

The immune checkpoint receptor LAG3: Structure, function, and target for cancer immunotherapy

Lymphocyte activation gene 3 protein (LAG3) is an immune checkpoint receptor that is highly upregulated on exhausted T cells in the tumor microenvironment. LAG3 transmits inhibitory signals to T cells upon binding to MHC class II and other ligands, rendering T cells dysfunctional. Consequently, LAG3 is a major target for cancer immunotherapy with many anti-LAG3 monoclonal antibodies (mAbs) that block LAG3 inhibitory activity in clinical trials. In this review, we examine the molecular basis for LAG3 function in light of recently determined crystal and cryoEM structures of this inhibitory receptor. We review what is known about LAG3 interactions with MHC class II, its canonical ligand, and the newly discovered ligands FGL1 and the T cell receptor (TCR)-CD3 complex, including current controversies over the relative importance of these ligands. We then address the development and mechanisms of action of anti-LAG3 mAbs in clinical trials for cancer immunotherapy. We discuss new strategies to therapeutically target LAG3 using mAbs that not only block the LAG3-MHC class II interaction, but also LAG3 interactions with FGL1 or TCR-CD3, or that disrupt LAG3 dimerization. Finally, we assess the possibility of developing mAbs that enhance, rather than block, LAG3 inhibitory activity as treatments for autoimmune diseases.

Current Landscape of Cancer Immunotherapy: Harnessing the Immune Arsenal to Overcome Immune Evasion

Cancer immune evasion represents a leading hallmark of cancer, posing a significant obstacle to the development of successful anticancer therapies. However, the landscape of cancer treatment has significantly evolved, transitioning into the era of immunotherapy from conventional methods such as surgical resection, radiotherapy, chemotherapy, and targeted drug therapy. Immunotherapy has emerged as a pivotal component in cancer treatment, harnessing the body's immune system to combat cancer and offering improved prognostic outcomes for numerous patients. The remarkable success of immunotherapy has spurred significant efforts to enhance the clinical efficacy of existing agents and strategies. Several immunotherapeutic approaches have received approval for targeted cancer treatments, while others are currently in preclinical and clinical trials. This review explores recent progress in unraveling the mechanisms of cancer immune evasion and evaluates the clinical effectiveness of diverse immunotherapy strategies, including cancer vaccines, adoptive cell therapy, and antibody-based treatments. It encompasses both established treatments and those currently under investigation, providing a comprehensive overview of efforts to combat cancer through immunological approaches. Additionally, the article emphasizes the current developments, limitations, and challenges in cancer immunotherapy. Furthermore, by integrating analyses of cancer immunotherapy resistance mechanisms and exploring combination strategies and personalized approaches, it offers valuable insights crucial for the development of novel anticancer immunotherapeutic strategies.

Outcomes and Adverse Events in Patients with Cancer after Diagnosis of Immunotherapy-Associated Diabetes Mellitus: A Retrospective Cohort Study

Immune checkpoint inhibitor (CPI)-induced diabetes mellitus (CPI-DM) is a rare immune-related adverse event (irAE). Patients and providers fear that continuing CPIs puts patients at risk for additional irAEs and thus may discontinue therapy. Currently, there are little data to inform this decision. Therefore, this study aims to elucidate whether discontinuing CPIs after diagnosis of CPI-DM impacts the development of future irAEs and cancer outcomes such as progression and death. Patients who developed CPI-DM during cancer treatment at UCSF from 1 July 2015 to 5 July 2023 were analyzed for cancer outcomes and irAE development. Fisher's exact tests, Student t-tests, Kaplan-Meier methods, and Cox regression were used as appropriate. Of the 43 patients with CPI-DM, 20 (47%) resumed CPIs within 90 days of the irAE, 4 (9%) patients restarted after 90 days, and 19 (44%) patients never restarted. Subsequent irAEs were diagnosed in 9 of 24 (38%) who resumed CPIs and 3 of 19 (16%) who discontinued CPIs (p = 0.17). There was no significant difference in death (p = 0.74) or cancer progression (p = 0.55) between these two groups. While our single-institution study did not show worse cancer outcomes after discontinuing CPIs, many variables can impact outcomes, which our study was not adequately powered to evaluate. A nuanced approach is needed to decide whether to continue CPI treatment after a severe irAE like CPI-DM.

Single-cell RNA sequencing explores the evolution of the ecosystem from leukoplakia to head and neck squamous cell carcinoma

It has been found that progression from leukoplakia to head and neck squamous cell carcinoma (HNSCC) is a long-term process that may involve changes in the multicellular ecosystem. We acquired scRNA-seq samples information from gene expression omnibus and UCSC Xena database. The BEAM function was used to construct the pseudotime trajectory and analyze the differentially expressed genes in different branches. We used the ssGSEA method to explore the correlation between each cell subgroup and survival time, and obtained the cell subgroup related to prognosis. During the progression from leukoplakia to HNSCC, we found several prognostic cell subgroups, such as AURKB + epithelial cells, SFRP1 + fibroblasts, SLC7A8 + macrophages, FCER1A + CD1C + dendritic cells, and TRGC2 + NK/T cells. All cell subgroups had two different fates, one tending to cell proliferation, migration, and enhancement of angiogenesis capacity, and the other tending to inflammatory immune response, leukocyte chemotaxis, and T cell activation. Tumor-promoting genes such as CD163 and CD209 were highly expressed in the myeloid cells, and depletion marker genes such as TIGIT, LAG3 were highly expressed in NK/T cells. Our study may provide a reference for the molecular mechanism of HNSCC and theoretical basis for the development of new therapeutic strategies.

Single-cell data revealed exhaustion of characteristic NK cell subpopulations and T cell subpopulations in hepatocellular carcinoma

BACKGROUND

The treatment and prognosis of patients with advanced hepatocellular carcinoma (HCC) have been a major medical challenge. Unraveling the landscape of tumor immune infiltrating cells (TIICs) in the immune microenvironment of HCC is of great significance to probe the molecular mechanisms.

METHODS

Based on single-cell data of HCC, the cell landscape was revealed from the perspective of TIICs. Special cell subpopulations were determined by the expression levels of marker genes. Differential expression analysis was conducted. The activity of each subpopulation was determined based on the highly expressed genes. CTLA4+ T-cell subpopulations affecting the prognosis of HCC were determined based on survival analysis. A single-cell regulatory network inference and clustering analysis was also performed to determine the transcription factor regulatory networks in the CTLA4+ T cell subpopulations.

RESULTS

10 cell types were identified and NK cells and T cells showed high abundance in tumor tissues. Two NK cells subpopulations were present, FGFBP2+ NK cells, B3GNT7+ NK cells. Four T cells subpopulations were present, LAG3+ T cells, CTLA4+ T cells, RCAN3+ T cells, and HPGDS+ Th2 cells. FGFBP2+ NK cells, and CTLA4+ T cells were the exhaustive subpopulation. High CTLA4+ T cells contributed to poor prognostic outcomes and promoted tumor progression. Finally, a network of transcription factors regulated by NR3C1, STAT1, and STAT3, which were activated, was present in CTLA4+ T cells.

CONCLUSION

CTLA4+ T cell subsets in HCC exhibited functional exhaustion characteristics that probably inhibited T cell function through a transcription factor network dominated by NR3C1, STAT1, and STAT3.

Stimulus-Responsive Copper Complex Nanoparticles Induce Cuproptosis for Augmented Cancer Immunotherapy

Cuproptosis, an emerging form of programmed cell death, has received tremendous attention in cancer therapy. However, the efficacy of cuproptosis remains limited by the poor delivery efficiency of copper ion carriers. Herein, copper complex nanoparticles (denoted as Cu(I) NP) are developed that can efficiently deliver copper complex into cancer cells to induce cuproptosis. Cu(I) NP demonstrate stimulus-responsive release of copper complexes, which results in mitochondrial dysfunction and promotes the aggregation of lipoylated dihydrolipoamide S-acetyltransferase (DLAT), leading to cuproptosis. Notably, Cu(I) NP not only induce cuproptosis, but also elicit robust immune responses to suppress tumor growth. Overall, this study provides a promising strategy for cuproptosis-based cancer therapy.

LAG-3, TIM-3, and TIGIT: Distinct functions in immune regulation

LAG-3, TIM-3, and TIGIT comprise the next generation of immune checkpoint receptors being harnessed in the clinic. Although initially studied for their roles in restraining T cell responses, intense investigation over the last several years has started to pinpoint the unique functions of these molecules in other immune cell types. Understanding the distinct processes that these receptors regulate across immune cells and tissues will inform the clinical development and application of therapies that either antagonize or agonize these receptors, as well as the profile of potential tissue toxicity associated with their targeting. Here, we discuss the distinct functions of LAG-3, TIM-3, and TIGIT, including their contributions to the regulation of immune cells beyond T cells, their roles in disease, and the implications for their targeting in the clinic.

Synergistic combination therapy using cowpea mosaic virus intratumoral immunotherapy and Lag-3 checkpoint blockade

Immune checkpoint therapy (ICT) for cancer can yield dramatic clinical responses; however, these may only be observed in a minority of patients. These responses can be further limited by subsequent disease recurrence and resistance. Combination immunotherapy strategies are being developed to overcome these limitations. We have previously reported enhanced efficacy of combined intratumoral cowpea mosaic virus immunotherapy (CPMV IIT) and ICT approaches. Lymphocyte-activation gene-3 (LAG-3) is a next-generation inhibitory immune checkpoint with broad expression across multiple immune cell subsets. Its expression increases on activated T cells and contributes to T cell exhaustion. We observed heightened efficacy of a combined CPMV IIT and anti-LAG-3 treatment in a mouse model of melanoma. Further, LAG-3 expression was found to be increased within the TME following intratumoral CPMV administration. The integration of CPMV IIT with LAG-3 inhibition holds significant potential to improve treatment outcomes by concurrently inducing a comprehensive anti-tumor immune response, enhancing local immune activation, and mitigating T cell exhaustion.

Lymphocyte-activation gene 3 (LAG-3) as a promising immune checkpoint in cancer immunotherapy: From biology to the clinic

In recent years, there have been notable advancements in the field of cancer immunotherapy, namely in the area of immune checkpoint inhibition. The Lymphocyte-activation gene 3 (LAG-3) has garnered attention as a potentially valuable focus of study in this particular field. The present study examines the biological aspects of LAG-3, its clinical consequences, and the potential therapeutic opportunities associated with its modulation. LAG-3, similar to CD4, has a regulatory role in modulating the immune system. The upregulation of this protein inside the neoplastic milieu hampers the immune system's ability to mount an effective response, hence enabling the evasion of cancer cells from immune surveillance. The LAG-3 protein interacts with ligands, inhibiting cytotoxic immune cells such as CD8+ T cells and NK cells. The potential of LAG-3 inhibitors presents intriguing prospects. Integrating these medicines with established treatments like PD-1/PD-L1 or CTLA-4 inhibitors can broaden the range of available therapy choices and address resistance issues. The advent of personalized therapy is imminent, as evidenced by the utilization of predictive biomarkers such as LAG-3 expression to inform individualized therapeutic approaches. Additionally, inhibitors of LAG-3 exhibit promise in addressing immunological depletion and resistance by revitalizing T cells and producing durable immune responses. The realization of LAG-3's promise necessitates global collaboration and equal access. Multinational trials are expected to ascertain the efficacy of the intervention in various patient groups.

Combinatorial immune checkpoint blockade increases myocardial expression of NLRP-3 and secretion of H-FABP, NT-Pro-BNP, interleukin-1β and interleukin-6: biochemical implications in cardio-immuno-oncology

Background

Immune checkpoint blockade in monotherapy or combinatorial regimens with chemotherapy or radiotherapy have become an integral part of oncology in recent years. Monoclonal antibodies against CTLA-4 or PD-1 or PDL-1 are the most studied ICIs in randomized clinical trials, however, more recently, an anti-LAG3 (Lymphocyte activation gene-3) antibody, Relatlimab, has been approved by FDA in combination with Nivolumab for metastatic melanoma therapy. Moreover, Atezolizumab is actually under study in association with Ipilimumab for therapy of metastatic lung cancer. Myocarditis, vasculitis and endothelitis are rarely observed in these patients on monotherapy, however new combination therapies could expose patients to more adverse cardiovascular events.

Methods

Human cardiomyocytes co-cultured with human peripheral blood lymphocytes (hPBMCs) were exposed to monotherapy and combinatorial ICIs (PD-L1 and CTLA-4 or PD-1 and LAG-3 blocking agents, at 100 nM) for 48 h. After treatments, cardiac cell lysis and secretion of biomarkers of cardiotoxicity (H-FABP, troponin-T, BNP, NT-Pro-BNP), NLRP3-inflammasome and Interleukin 1 and 6 were determined through colorimetric and enzymatic assays. Mitochondrial functions were studied in cardiomyocyte cell lysates through quantification of intracellular Ca++, ATP content and NADH:ubiquinone oxidoreductase core subunit S1 (Ndufs1) levels. Histone deacetylases type 4 (HDAC-4) protein levels were also determined in cardiomyocyte cell lysates to study potential epigenetic changes induced by immunotherapy regimens.

Results

Both combinations of immune checkpoint inhibitors exert more potent cardiotoxic side effects compared to monotherapies against human cardiac cells co-cultured with human lymphocytes. LDH release from cardiac cells was 43% higher in PD-L1/CTLA-4 blocking agents, and 35.7% higher in PD-1/LAG-3 blocking agents compared to monotherapies. HDAC4 and intracellular Ca++ levels were increased, instead ATP content and Ndufs1 were reduced in myocardial cell lysates (p < 0.001 vs. untreated cells). Troponin-T, BNP, NT-Pro-BNP and H-FABP, were also strongly increased in combination therapy compared to monotherapy regimen. NLRP3 expression, IL-6 and IL-1β levels were also increased by PDL-1/CTLA-4 and PD-1/LAG-3 combined blocking agents compared to untreated cells and monotherapies.

Conclusions

Data of the present study, although in vitro, indicate that combinatorial immune checkpoint blockade, induce a pro- inflammatory phenotype, thus indicating that these therapies should be closely monitored by the multidisciplinary team consisting of oncologists, cardiologists and immunologists.

Noninvasive Monitoring of Immunotherapy in Lung Cancer by Lymphocyte Activation Gene 3 PET Imaging of Tumor-Infiltrating Lymphocytes

Although immunotherapy has revolutionized the entire cancer treatment landscape, small fractions of patients respond to immunotherapy. Early identification of responders may improve patient management during immunotherapy. In this study, we evaluated a PET approach for monitoring immunotherapy in lung cancer by imaging the upregulation of lymphocyte activation gene 3 (LAG-3)-expressing (LAG-3+) tumor-infiltrating lymphocytes (TILs). Methods: We synthesized a LAG-3-targeted molecular imaging probe, [68Ga]Ga-NOTA-C25 and performed a series of in vitro and in vivo assays to test its specificity. Next, [68Ga]Ga-NOTA-C25 PET was used to monitor immunotherapy in murine lung cancer-bearing mice and in humanized mouse models for assessing clinical translational potential, with confirmation by immunostaining and flow cytometry analysis. Results: [68Ga]Ga-NOTA-C25 PET could noninvasively detect intertumoral differences in LAG-3+ TIL levels in different tumor models. Importantly, in Lewis lung carcinoma tumor models treated with an agonist of a stimulator of interferon genes, [68Ga]Ga-NOTA-C25 PET also detected an immunophenotyping transition of the tumor from "cold" to "hot" before changes in tumor size. Meanwhile, animals carrying "hot" tumor showed more significant tumor inhibition and longer survival than those carrying "cold" tumor. [68Ga]Ga-NOTA-C25 PET also showed markedly higher tumor uptake in immune system-humanized mice carrying human non-small cell lung cancer than immunodeficient models. Conclusion: [68Ga]Ga-NOTA-C25 PET could be used to noninvasively monitor the early response to immunotherapy by imaging LAG-3+ TILs in lung cancer. [68Ga]Ga-NOTA-C25 PET also exhibited excellent translational potential, with great significance for the precise management of lung cancer patients receiving immunotherapy.

Periprosthetic joint infection and immunity: Current understanding of host-microbe interplay

Periprosthetic joint infection (PJI) is a major complication of total joint arthroplasty. Even with current treatments, failure rates are unacceptably high with a 5-year mortality rate of 26%. Majority of the literature in the field has focused on development of better biomarkers for diagnostics and treatment strategies including innovate antibiotic delivery systems, antibiofilm agents, and bacteriophages. Nevertheless, the role of the immune system, our first line of defense during PJI, is not well understood. Evidence of infection in PJI patients is found within circulation, synovial fluid, and tissue and include numerous cytokines, metabolites, antimicrobial peptides, and soluble receptors that are part of the PJI diagnosis workup. Macrophages, neutrophils, and myeloid-derived suppressor cells (MDSCs) are initially recruited into the joint by chemokines and cytokines produced by immune cells and bacteria and are activated by pathogen-associated molecular patterns. While these cells are efficient killers of planktonic bacteria by phagocytosis, opsonization, degranulation, and recruitment of adaptive immune cells, biofilm-associated bacteria are troublesome. Biofilm is not only a physical barrier for the immune system but also elicits effector functions. Additionally, bacteria have developed mechanisms to evade the immune system by inactivating effector molecules, promoting killing or anti-inflammatory effector cell phenotypes, and intracellular persistence and dissemination. Understanding these shortcomings and the mechanisms by which bacteria can subvert the immune system may open new approaches to better prepare our own immune system to combat PJI. Furthermore, preoperative immune system assessment and screening for dysregulation may aid in developing preventative interventions to decrease PJI incidence.

Leveraging an immune cell signature to improve the survival and immunotherapy response of lung adenocarcinoma

Background: Immune cells play a critical role in the prognosis of cancer. However, the function of different immune cell types in lung adenocarcinoma (LUAD) and the development of a prognostic signature based on immune cell types have not been comprehensively investigated. Methods: We collected and included a total of 2499 LUAD patients and performed calculations to determine the penetration level of 24 immune cells. This examination was conducted using the macro-gene-based approach provided by ImmuCellAI. We performed a meta-analysis using Lasso-Cox analysis to establish the immune cell pair score (ICPS). We conducted a survival analysis to measure differences in survival across ICPS-risk groups. Wilcox test was used to measure the difference in expression level. Spearman correlation analysis was used for the relevance assessment. Results: We collected a total of 24 immune cell types to construct cell pairs. Utilizing 17 immune cell pairs, we constructed and validated the ICPS, which plays a critical role in stratifying survival and dynamically monitoring the effectiveness of immunotherapy. Additionally, we identified several candidate drugs that target ICPS. Conclusions: The ICPS shows promise as a valuable tool for identifying suitable candidates for immunotherapy among patients. Our comprehensive assessment of immune cell interactions in LUAD contributes to a deeper understanding of infiltration patterns and functions, thereby guiding the development of more efficacious immunotherapy strategies.

LAG3 is an independent prognostic biomarker and potential target for immune checkpoint inhibitors in malignant pleural mesothelioma: a retrospective study

BACKGROUND

Lymphocyte-activation gene 3 (LAG3) is an immune checkpoint receptor; novel LAG3 immune checkpoint inhibitors (ICIs) exhibit therapeutic activity in melanoma. The role of LAG3and ICIs of LAG3 are unknown in malignant pleural mesothelioma (MPM). This study aimed to uncover the prognostic landscape of LAG3 in multiple cancers and investigate the potential of using LAG3 as an ICIs target in patients with MPM.

METHODS

We used The Cancer Genome Atlas (TCGA) cohort for assessing mRNA expression and our cohort for immunohistochemical expression. TCGA cohort were analyzed using the Wilcoxon rank-sum test to compare mRNA expression between normal and tumor tissues in multiple cancers. We used 86 MPM cases from TCGA and 38 MPM cases from our cohort to analyze the expression of LAG3 in tumor-infiltrating lymphocytes. The mean LAG3 mRNA expression was set as the cut-off and samples were classified as positive/negative for immunohistochemical expression. Overall survival (OS) of patients with MPM was determined using the Kaplan-Meier method based on LAG3 mRNA and immunohistochemical expression. OS analysis was performed using the multivariate Cox proportional hazards model. The correlation of LAG3 expression and mRNA expression of tumor immune infiltration cells (TIICs) gene markers were estimated using Spearman correlation. To identify factors affecting the correlation of LAG3 mRNA expression, a multivariate linear regression model was performed.

RESULTS

LAG3 mRNA was associated with prognosis in multiple cancers. Elevated LAG3 mRNA expression was correlated with a better prognosis in MPM. LAG3 expression was detected immunohistochemically in the membrane of infiltrating lymphocytes in MPM. LAG3 immunohistochemical expression was correlated with a better prognosis in MPM. The multivariate Cox proportional hazards model revealed that elevated LAG3 immunohistochemical expression indicated a better prognosis. In addition, LAG3 mRNA expression was correlated with the expression of various gene markers of TIICs, the most relevant to programmed cell death 1 (PD-1) with the multivariate linear regression model in MPM.

CONCLUSIONS

LAG3 expression was correlated with prognosis in multiple cancers, particularly MPM; LAG3 is an independent prognostic biomarker of MPM. LAG3 regulates cancer immunity and is a potential target for ICIs therapy. PD-1 and LAG3 inhibitors may contribute to a better prognosis in MPM.

TRIAL REGISTRATION

This study was registered with UMIN000049240 (registration day: August 19, 2022) and approved by the Institutional Review Board (approval date: August 22, 2022; approval number: 2022-0048) at Tokyo Women's Medical University.

Supervised clustering of peripheral immune cells associated with clinical response to checkpoint inhibitor therapy in patients with advanced melanoma

Background and purpose

Immune therapy with checkpoint inhibitors (CPIs) is a highly successful therapy in many cancers including metastatic melanoma. Still, many patients do not respond well to therapy and there are no blood-borne biomarkers available to assess the clinical outcome.

Materials and methods

To investigate cellular changes after CPI therapy, we carried out flow cytometry-based immune monitoring in a cohort of 90 metastatic melanoma patients before and after CPI therapy using the FlowSOM algorithm. To evaluate associations to the clinical outcome with therapy, we divided the patients based on progression-free survival.

Results

We found significant associations with CPI therapy in both peripheral blood mononuclear cell and T-cell subsets, but with the most pronounced effects in the latter. Particularly CD4+ effector memory T-cell subsets were associated with response with a positive correlation between CD27+HLA-DR+CD4+ effector memory T cells in a univariate (odds ratio: 1.07 [95% confidence interval 1.02-1.12]) and multivariate regression model (odds ratio: 1.08 [95% confidence interval 1.03-1.14]). We also found a trend towards stronger accumulation of CD57+CD8+ T cells in non-responding patients.

Conclusion

Our results show significant associations between immune monitoring and clinical outcome of therapy that could be evaluated as biomarkers in a clinical setting.

Curcumin analog GO-Y030 inhibits tumor metastasis and glycolysis

Tumor metastasis is one of the worst prognostic features of cancer. Although metastasis is a major cause of cancer-related deaths, an effective treatment has not yet been established. Here, we explore the antitumor effects of GO-Y030, a curcumin analog, via various mechanisms using a mouse model. GO-Y030 treatment of B16-F10 melanoma cells inhibited TGF-β expression and glycolysis. The invasion assay results showed almost complete invasion inhibition following GO-Y030 treatment. Mouse experiments demonstrated that GO-Y030 administration inhibited lung tumor metastasis without affecting vascular endothelial cells. Consistent with this result, GO-Y030 treatment led to the downregulation of MMP2 and VEGFα, inhibiting tumor invasion and metastasis. The silencing of eIF4B, a downstream molecule of S6, attenuated MMP2 expression. Our study demonstrates the novel efficacy of GO-Y030 in inhibiting tumor metastasis by regulating metastasis-associated gene expression via inhibiting dual access, glycolytic and TGF-β pathways.

The PD-1- and LAG-3-targeting bispecific molecule tebotelimab in solid tumors and hematologic cancers: a phase 1 trial

Tebotelimab, a bispecific PD-1×LAG-3 DART molecule that blocks both PD-1 and LAG-3, was investigated for clinical safety and activity in a phase 1 dose-escalation and cohort-expansion clinical trial in patients with solid tumors or hematologic malignancies and disease progression on previous treatment. Primary endpoints were safety and maximum tolerated dose of tebotelimab when administered as a single agent (n = 269) or in combination with the anti-HER2 antibody margetuximab (n = 84). Secondary endpoints included anti-tumor activity. In patients with advanced cancer treated with tebotelimab monotherapy, 68% (184/269) experienced treatment-related adverse events (TRAEs; 22% were grade ≥3). No maximum tolerated dose was defined; the recommended phase 2 dose (RP2D) was 600 mg once every 2 weeks. There were tumor decreases in 34% (59/172) of response-evaluable patients in the dose-escalation cohorts, with objective responses in multiple solid tumor types, including PD-1-refractory disease, and in LAG-3+ non-Hodgkin lymphomas, including CAR-T refractory disease. To enhance potential anti-tumor responses, we tested margetuximab plus tebotelimab. In patients with HER2+ tumors treated with tebotelimab plus margetuximab, 74% (62/84) had TRAEs (17% were grade ≥3). The RP2D was 600 mg once every 3 weeks. The confirmed objective response rate in these patients was 19% (14/72), including responses in patients typically not responsive to anti-HER2/anti-PD-1 combination therapy. ClinicalTrials.gov identifier: NCT03219268 .

Combinatorial blockade for cancer immunotherapy: targeting emerging immune checkpoint receptors

The differentiation, survival, and effector function of tumor-specific CD8+ cytotoxic T cells lie at the center of antitumor immunity. Due to the lack of proper costimulation and the abundant immunosuppressive mechanisms, tumor-specific T cells show a lack of persistence and exhausted and dysfunctional phenotypes. Multiple coinhibitory receptors, such as PD-1, CTLA-4, VISTA, TIGIT, TIM-3, and LAG-3, contribute to dysfunctional CTLs and failed antitumor immunity. These coinhibitory receptors are collectively called immune checkpoint receptors (ICRs). Immune checkpoint inhibitors (ICIs) targeting these ICRs have become the cornerstone for cancer immunotherapy as they have established new clinical paradigms for an expanding range of previously untreatable cancers. Given the nonredundant yet convergent molecular pathways mediated by various ICRs, combinatorial immunotherapies are being tested to bring synergistic benefits to patients. In this review, we summarize the mechanisms of several emerging ICRs, including VISTA, TIGIT, TIM-3, and LAG-3, and the preclinical and clinical data supporting combinatorial strategies to improve existing ICI therapies.

Case report: Identification of potential prognosis-related LAG3 overexpression and DICER1 mutation in pituitary carcinoma: two cases

Metastatic PitNETs are a rare life-threatening condition with poor prognosis and documentation. Due to the scarce literature and lack of precise treatment, we hope to better characterise PitNET using the next-generation whole exon sequencing (WES) and RNA sequencing. This case study outlines a 54 years-old man and a 52 years-old woman who were both diagnosed with PitNET and analysis of peripheral blood and tumours were performed by WES and RNA sequencing. Analysis showed that DICER1 mutations in precancerous lesions and LAG3 overexpression were significant in aiding the prognosis and diagnosis of PitNETs. The first case with overexpressed LAG3 and DICER1 mutation died 26 months later, and the second case with LAG3 overexpression achieved partial remission. This study revealed that heightened expression of LAG3 offered promising targets for ICI and mutations in DICER1 could provide markers for effective diagnosis and prognosis.

CryoEM structure of a therapeutic antibody (favezelimab) bound to human LAG3 determined using a bivalent Fab as fiducial marker

Lymphocyte activation gene 3 protein (LAG3) is an inhibitory receptor that is upregulated on exhausted T cells in tumors. LAG3 is a major target for cancer immunotherapy with many anti-LAG3 antibodies in clinical trials. However, there is no structural information on the epitopes recognized by these antibodies. We determined the single-particle cryoEM structure of a therapeutic antibody (favezelimab) bound to LAG3 to 3.5 Å resolution, revealing that favezelimab targets the LAG3-binding site for MHC class II, its canonical ligand. The small size of the complex between the conventional (monovalent) Fab of favezelimab and LAG3 (∼100 kDa) presented a challenge for cryoEM. Accordingly, we engineered a bivalent version of Fab favezelimab that doubled the size of the Fab-LAG3 complex and conferred a highly identifiable shape to the complex that facilitated particle selection and orientation for image processing. This study establishes bivalent Fabs as new fiducial markers for cryoEM analysis of small proteins.

The ligand-dependent suppression of TCR signaling by the immune checkpoint receptor LAG3 depends on the cytoplasmic RRFSALE motif

Lymphocyte activation gene 3 (LAG3) is an inhibitory immune checkpoint receptor that restrains autoimmune and antitumor responses, but its evolutionarily conserved cytoplasmic tail lacks classical inhibitory motifs. Major histocompatibility complex class II (MHC class II) is an established LAG3 ligand, and fibrinogen-like protein 1 (FGL1), lymph node sinusoidal endothelial cell C-type lectin (LSECtin), and Galectin-3 have been proposed as alternative binding partners that play important roles in LAG3 function. Here, we used a fluorescent human T cell reporter system to study the function of LAG3. We found that LAG3 reduced the response to T cell receptor stimulation in the presence of MHC class II molecules to a lesser extent compared with the receptor programmed cell death protein 1. Analysis of deletion mutants demonstrated that the RRFSALE motif in the cytoplasmic tail of LAG3 was necessary and sufficient for LAG3-mediated inhibition. In this system, FGL1, but not LSECtin or Galectin-3, acted as a LAG3 ligand that weakly induced inhibition. LAG3-blocking antibodies attenuated LAG3-mediated inhibition in our reporter cells and enhanced reporter cell activation even in the absence of LAG3 ligands, indicating that they could potentially enhance T cell responses independently of their blocking effect.

Immune interactions in pembrolizumab (PD-1 inhibitor) cancer therapy and cardiovascular complications

The use of immunotherapies like pembrolizumab (PEM) is increasingly common for the management of numerous cancer types. The use of PEM to bolster T-cell response against tumor growth is well documented. However, the interactions PEM has on other immune cells to facilitate tumor regression and clearance is unknown and warrants further investigation. In this review, we present literature findings that have reported the interactions of PEM in stimulating innate and adaptive immune cells, which enhance cytotoxic phenotypes. This triggers secretion of cytokines and chemokines, which have both beneficial and detrimental effects. We also describe how this leads to the development of rare but underreported occurrence of PEM-induced immune-related cardiovascular complications that arise suddenly and progress rapidly to debilitating and fatal consequences. This review encourages further research and investigation of PEM-induced cardiovascular complications and other immune cell interactions in patients with cancer. As PEM therapy in treating cancer types is expanding, we expect that this review will inform health care professionals of diverse specializations of medicine like dermatology (melanoma skin cancers), ophthalmology (eye cancers), and pathology (hematological malignancies) about PEM-induced cardiac complications.

Microbiota-dependent regulation of costimulatory and coinhibitory pathways via innate immune sensors and implications for immunotherapy

Our bodies are inhabited by trillions of microorganisms. The host immune system constantly interacts with the microbiota in barrier organs, including the intestines. Over decades, numerous studies have shown that our mucosal immune system is dynamically shaped by a variety of microbiota-derived signals. Elucidating the mediators of these interactions is an important step for understanding how the microbiota is linked to mucosal immune homeostasis and gut-associated diseases. Interestingly, the efficacy of cancer immunotherapies that manipulate costimulatory and coinhibitory pathways has been correlated with the gut microbiota. Moreover, adverse effects of these therapies in the gut are linked to dysregulation of the intestinal immune system. These findings suggest that costimulatory pathways in the immune system might serve as a bridge between the host immune system and the gut microbiota. Here, we review mechanisms by which commensal microorganisms signal immune cells and their potential impact on costimulation. We highlight how costimulatory pathways modulate the mucosal immune system through not only classical antigen-presenting cells but also innate lymphocytes, which are highly enriched in barrier organs. Finally, we discuss the adverse effects of immune checkpoint inhibitors in the gut and the possible relationship with the gut microbiota.

Immune gene signatures as prognostic criteria for cancer patients

Recently, the possibility of using immune gene signatures (IGSs) has been considered as a novel prognostic tool for numerous cancer types. State-of-the-art methods of genomic, transcriptomic, and protein analysis have allowed the identification of a number of immune signatures correlated to disease outcome. The major adaptive and innate immune components are the T lymphocytes and macrophages, respectively. Herein, we collected essential data on IGSs consisting of subsets of T cells and tumor-associated macrophages and indicating cancer patient outcomes. We discuss factors that can introduce errors in the recognition of immune cell types and explain why the significance of immune signatures can be interpreted with uncertainty. The unidirectional functions of cell types should be entirely addressed in the signatures constructed by the combination of innate and adaptive immune cells. The state of the antitumor immune response is the key basis for IGSs and should be considered in gene signature construction. We also analyzed immune signatures for the prediction of immunotherapy response. Finally, we attempted to explain the present-day limitations in the use of immune signatures as robust criteria for prognosis.

The introduction of LAG-3 checkpoint blockade in melanoma: immunotherapy landscape beyond PD-1 and CTLA-4 inhibition

Despite major advances with immunotherapy and targeted therapy in the past decade, metastatic melanoma continues to be a deadly disease for close to half of all patients. Over the past decade, advancement in immune profiling and a deeper understanding of the immune tumor microenvironment (TME) have enabled the development of novel approaches targeting and a multitude of targets being investigated for the immunotherapy of melanoma. However, to date, immune checkpoint blockade has remained the most successful with programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) inhibitors, alone or in combination, yielding the most robust and durable clinical outcome in patients with metastatic melanoma. The highest rate of durable responses is achieved with the combination with PD-1 and CTLA-4 inhibition, and is effective in a variety of settings including brain metastases; however, it comes at the expense of a multitude of life-threatening toxicities occurring in up to 60% of patients. This has also established melanoma as the forefront of immuno-oncology (IO) drug development, and the search for novel checkpoints has been ongoing with multiple relevant targets including T-cell immunoglobulin and mucinodomain containing-3 (TIM-3), LAG-3, V-domain immunoglobulin suppressor T-cell activation (VISTA), T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), among others. Lymphocyte activation gene-3 (LAG-3), which is a co-inhibitory receptor on T cells that suppress their activation, has revolutionized immunomodulation in melanoma. The 'game changing' results from the RELATIVITY-047 trial validated LAG-3 blockade as a relevant biological target and established it as the third clinically relevant immune checkpoint. Importantly, LAG-3 inhibition in combination with PD-1 inhibition offered impressive efficacy with modest increases in toxicity over single agent PD-1 inhibitor and has been U.S. Food and Drug Administration approved for the first-line therapy of patients with metastatic melanoma. The efficacy of this combination in patients with untreated brain or leptomeningeal metastases or with rare melanoma types, such as uveal melanoma, remains to be established. The challenge remains to elucidate specific mechanisms of response and resistance to LAG-3 blockade and to extend its benefits to other malignancies. Ongoing trials are studying the combination of LAG-3 antibodies with PD-1 inhibitors in multiple cancers and settings. The low toxicity of the combination may also allow for further layering of additional therapeutic approaches such as chemotherapy, oncolytic viruses, cellular therapies, and possibly novel cytokines, among others.

Discovery of First-in-Class Small Molecule Inhibitors of Lymphocyte Activation Gene 3 (LAG-3)

Lymphocyte activation gene 3 (LAG-3) is a negative immune checkpoint that plays a key role in downregulating the immune response to cancer. Inhibition of LAG-3 interactions allows T cells to regain cytotoxic activity and reduce the immunosuppressive function of regulating T cells. We utilized a combination approach of focused screening and "SAR by catalog" to identify small molecules that function as dual inhibitors of the interactions of LAG-3 with major histocompatibility complex (MHC) class II and fibrinogen-like protein 1 (FGL1). Our top hit compound inhibited both LAG-3/MHCII and LAG-3/FGL1 interactions in biochemical binding assays with IC50 values of 4.21 ± 0.84 and 6.52 ± 0.47 μM, respectively. Moreover, we have demonstrated the ability of our top hit compound to block LAG-3 interactions in cell-based assays. This work will pave the way for future drug discovery efforts aiming at the development of LAG-3-based small molecules for cancer immunotherapy.

Development of a high-throughput TR-FRET screening assay for LAG-3/FGL1 interaction

Lymphocyte activation gene 3 (LAG-3) is a negative immune checkpoint and a key regulator of immune homeostasis with multiple biological activities related to T-cell functions. Fibrinogen-like protein 1 (FGL1) is a major LAG-3 functional ligand that is upregulated in various human cancers. LAG-3 positive T cells bind FGL1 expressed by cancer cells, which inhibits T-cell activation and cytokine secretion via indirect blocking of T cell receptor (TCR) signaling. High expression of LAG-3 and FGL1 in patients with solid tumors is associated with drug resistance and decreased survival in response to FDA-approved immune checkpoint inhibitors. Therefore, targeting the LAG-3/FGL1 pathway represents a promising therapeutic strategy to maximize the number of patients benefiting from checkpoint blockade therapy. However, there are no small molecules in existence that target LAG-3/FGL1 interaction. Herein, we report a time-resolved fluorescence resonance energy transfer (TR-FRET) assay to evaluate the ability of small molecules to inhibit LAG-3/FGL1 interaction. We further demonstrate the implementation of the developed assay in screening chemical libraries of small molecules from the NCI Diversity Set VII, FDA-approved drugs, and a focused library of NF-κB modulators. This work will pave the way for drug discovery efforts focused on therapeutic targeting of LAG-3/FGL1 interaction using small molecules.

"To be or not to Be": Regulatory T cells in melanoma

In spite of progresses in the therapy of different malignancies, melanoma still remains as one of lethal types of skin tumor. Melanoma is almost easily treatable by surgery alone with higher overall survival rates when it is diagnosed at early stages. However, survival rates are decreased remarkably upon survival if the tumor is progressed to advanced metastatic stages. Immunotherapeutics have been prosperous in the development of anti-tumor responses in patients with melanoma through promotion of the tumor-specific effector T cells in vivo; nonetheless, suitable clinical outcomes have not been satisfactory. One of the underlying causes of the unfavorable clinical outcomes might stem from adverse effects of regulatory T (Treg) cell, which is a prominent mechanism of tumor cells to escape from tumor-specific immune responses. Evidence shows that a poor prognosis and low survival rate in patients with melanoma can be attributed to a higher Treg cell number and function in these subjects. As a result, to promote melanoma-specific anti-tumor responses, depletion of Treg cells appears to be a promising approach; even though the clinical efficacy of different approaches to attain appropriate Treg cell depletion has been inconsistent. Here in this review, the main purpose is to assess the role of Treg cells in the initiation and perpetuation of melanoma and to discuss effective strategies for Treg cell modulation with the aim of melanoma therapy.

Interferon Biology and LAG-3 Shedding in PD-(L)1 plus LAG-3 Immunotherapy

Targeting coinhibitory receptors on dysfunctional T cells may improve response to anti-PD-(L)1 in the IFNγ associated T-cell-inflamed tumor microenvironment. The bispecific lymphocyte activation gene 3 (LAG-3) and PD-L1 blocking antibody FS118, potentially through LAG-3 shedding, represents a promising strategy to improve immune checkpoint blockade. Soluble LAG-3 is an intriguing biomarker for LAG-3 drug activity. See related article by Yap et al., p. 888.

Role of myeloid-derived suppressor cells in tumor recurrence

The establishment of primary tumor cells in distant organs, termed metastasis, is the principal cause of cancer mortality and is a crucial therapeutic target in oncology. Thus, it is critical to establish a better understanding of metastatic progression for the future development of improved therapeutic approaches. Indeed, such development requires insight into the timing of tumor cell dissemination and seeding of distant organs resulting in occult lesions. Following dissemination of tumor cells from the primary tumor, they can reside in niches in distant organs for years or decades, following which they can emerge as an overt metastasis. This timeline of metastatic dormancy is regulated by interactions between the tumor, its microenvironment, angiogenesis, and tumor antigen-specific T-cell responses. An improved understanding of the mechanisms and interactions responsible for immune evasion and tumor cell release from dormancy would help identify and aid in the development of novel targeted therapeutics. One such mediator of dormancy is myeloid derived suppressor cells (MDSC), whose number in the peripheral blood (PB) or infiltrating tumors has been associated with cancer stage, grade, patient survival, and metastasis in a broad range of tumor pathologies. Thus, extensive studies have revealed a role for MDSCs in tumor escape from adoptive and innate immune responses, facilitating tumor progression and metastasis; however, few studies have considered their role in dormancy. We have posited that MDSCs may regulate disseminated tumor cells resulting in resurgence of senescent tumor cells. In this review, we discuss clinical studies that address mechanisms of tumor recurrence including from dormancy, the role of MDSCs in their escape from dormancy during recurrence, the development of occult metastases, and the potential for MDSC inhibition as an approach to prolong the survival of patients with advanced malignancies. We stress that assessing the impact of therapies on MDSCs versus other cellular targets is challenging within the multimodality interventions required clinically.

Comparison of efficacy and tolerability of adjuvant therapy for resected high-risk stage III-IV cutaneous melanoma: a systemic review and Bayesian network meta-analysis

Background

Although immune checkpoint inhibitors (ICIs) and targeted therapies have been widely used as adjuvant treatment for resected melanoma, the optimal therapy remains controversial. Therefore, we conducted this updated network meta-analysis (NMA) to assess the efficacy and tolerability of adjuvant therapies for cutaneous melanoma.

Methods

PubMed, Embase, Cochrane library, and Web of Science were systematically searched for relevant literatures published in the last 30 years. Disease-free survival (DFS), overall survival (OS), and serious adverse events were considered as the efficacy and tolerability outcomes.

Results

In all, 27 randomized controlled trials (RCTs) including 16,709 stage III-IV melanoma patients were enrolled in this NMA. For BRAF wild-type melanoma, our analysis showed that both nivolumab and pembrolizumab demonstrated significantly better DFS and tolerability than ipilimumab (10 mg/kg). Nivolumab, pembrolizumab, ipilimumab (3 mg/kg), and ipilimumab (10 mg/kg) all appeared to be effective in prolonging OS, but no therapy demonstrated significantly better OS than ipilimumab (10 mg/kg). Nivolumab + ipilimumab showed the best DFS, but did not appear to be effective in improving OS and ranked only seventh in tolerability. Vaccines and granulocyte-macrophage colony-stimulating factor therapies were well tolerated, but all failed to improve the DFS or OS in stage III melanoma patients. In terms of BRAF mutation-positive melanoma, ICIs (nivolumab + ipilimumab, nivolumab, pembrolizumab, ipilimumab; 10 mg/kg) exhibited comparable efficacy to dabrafenib + trametinib, and all these therapies showed significantly better DFS than placebo.

Conclusion

Considering efficacy and tolerability, nivolumab and pembrolizumab seem to be preferable adjuvant therapies for patients with stage III-IV melanoma. For BRAF mutation-positive patients, more RCTs are still required to determine which is better between ICIs and targeted therapy.

Targeting toll-like receptor 7/8 for immunotherapy: recent advances and prospectives

Toll-like receptors (TLRs) are a large family of proteins that are expressed in immune cells and various tumor cells. TLR7/8 are located in the intracellular endosomes, participate in tumor immune surveillance and play different roles in tumor growth. Activation of TLRs 7 and 8 triggers induction of a Th1 type innate immune response in the highly sophisticated process of innate immunity signaling with the recent research advances involving the small molecule activation of TLR 7 and 8. The wide range of expression and clinical significance of TLR7/TLR8 in different kinds of cancers have been extensively explored. TLR7/TLR8 can be used as novel diagnostic biomarkers, progression and prognostic indicators, and immunotherapeutic targets for various tumors. Although the mechanism of action of TLR7/8 in cancer immunotherapy is still incomplete, TLRs on T cells are involved in the regulation of T cell function and serve as co-stimulatory molecules and activate T cell immunity. TLR agonists can activate T cell-mediated antitumor responses with both innate and adaptive immune responses to improve tumor therapy. Recently, novel drugs of TLR7 or TLR8 agonists with different scaffolds have been developed. These agonists lead to the induction of certain cytokines and chemokines that can be applied to the treatment of some diseases and can be used as good adjutants for vaccines. Furthermore, TLR7/8 agonists as potential therapeutics for tumor-targeted immunotherapy have been developed. In this review, we summarize the recent advances in the development of immunotherapy strategies targeting TLR7/8 in patients with various cancers and chronic hepatitis B.

Isolated BAP1 Genomic Alteration in Malignant Pleural Mesothelioma Predicts Distinct Immunogenicity with Implications for Immunotherapeutic Response

Malignant pleural mesothelioma (MPM), an aggressive cancer of the mesothelial cells lining the pleural cavity, lacks effective treatments. Multiple somatic mutations and copy number losses in tumor suppressor genes (TSGs) BAP1, CDKN2A/B, and NF2 are frequently associated with MPM. The impact of single versus multiple genomic alterations of TSG on MPM biology, the immune tumor microenvironment, clinical outcomes, and treatment responses are unknown. Tumors with genomic alterations in BAP1 alone were associated with a longer overall patient survival rate compared to tumors with CDKN2A/B and/or NF2 alterations with or without BAP1 and formed a distinct immunogenic subtype with altered transcription factor and pathway activity patterns. CDKN2A/B genomic alterations consistently contributed to an adverse clinical outcome. Since the genomic alterations of only BAP1 was associated with the PD-1 therapy response signature and higher LAG3 and VISTA gene expression, it might be a candidate marker for immune checkpoint blockade therapy. Our results on the impact of TSG genotypes on MPM and the correlations between TSG alterations and molecular pathways provide a foundation for developing individualized MPM therapies.

Epitope Mapping of Therapeutic Antibodies Targeting Human LAG3

Lymphocyte activation gene 3 protein (LAG3; CD223) is an inhibitory receptor that is highly upregulated on exhausted T cells in tumors and chronic viral infection. Consequently, LAG3 is now a major immunotherapeutic target for the treatment of cancer, and many mAbs against human (h) LAG3 (hLAG3) have been generated to block its inhibitory activity. However, little or no information is available on the epitopes they recognize. We selected a panel of seven therapeutic mAbs from the patent literature for detailed characterization. These mAbs were expressed as Fab or single-chain variable fragments and shown to bind hLAG3 with nanomolar affinities, as measured by biolayer interferometry. Using competitive binding assays, we found that the seven mAbs recognize four distinct epitopes on hLAG3. To localize the epitopes, we carried out epitope mapping using chimeras between hLAG3 and mouse LAG3. All seven mAbs are directed against the first Ig-like domain (D1) of hLAG3, despite their different origins. Three mAbs almost exclusively target a unique 30-residue loop of D1 that forms at least part of the putative binding site for MHC class II, whereas four mainly recognize D1 determinants outside this loop. However, because all the mAbs block binding of hLAG3 to MHC class II, each of the epitopes they recognize must at least partially overlap the MHC class II binding site.

Emerging roles for IL-25 and IL-33 in colorectal cancer tumorigenesis

Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide, and is largely refractory to current immunotherapeutic interventions. The lack of efficacy of existing cancer immunotherapies in CRC reflects the complex nature of the unique intestinal immune environment, which serves to maintain barrier integrity against pathogens and harmful environmental stimuli while sustaining host-microbe symbiosis during homeostasis. With their expression by barrier epithelial cells, the cytokines interleukin-25 (IL-25) and IL-33 play key roles in intestinal immune responses, and have been associated with inappropriate allergic reactions, autoimmune diseases and cancer pathology. Studies in the past decade have begun to uncover the important roles of IL-25 and IL-33 in shaping the CRC tumour immune microenvironment, where they may promote or inhibit tumorigenesis depending on the specific CRC subtype. Notably, both IL-25 and IL-33 have been shown to act on group 2 innate lymphoid cells (ILC2s), but can also stimulate an array of other innate and adaptive immune cell types. Though sometimes their functions can overlap they can also produce distinct phenotypes dependent on the differential distribution of their receptor expression. Furthermore, both IL-25 and IL-33 modulate pathways previously known to contribute to CRC tumorigenesis, including angiogenesis, tumour stemness, invasion and metastasis. Here, we review our current understanding of IL-25 and IL-33 in CRC tumorigenesis, with specific focus on dissecting their individual function in the context of distinct subtypes of CRC, and the potential prospects for targeting these pathways in CRC immunotherapy.

Emerging Trends in Immunotherapy for Cancer

Recent advances in cancer immunology have enabled the discovery of promising immunotherapies for various malignancies that have shifted the cancer treatment paradigm. The innovative research and clinical advancements of immunotherapy approaches have prolonged the survival of patients with relapsed or refractory metastatic cancers. Since the U.S. FDA approved the first immune checkpoint inhibitor in 2011, the field of cancer immunotherapy has grown exponentially. Multiple therapeutic approaches or agents to manipulate different aspects of the immune system are currently in development. These include cancer vaccines, adoptive cell therapies (such as CAR-T or NK cell therapy), monoclonal antibodies, cytokine therapies, oncolytic viruses, and inhibitors targeting immune checkpoints that have demonstrated promising clinical efficacy. Multiple immunotherapeutic approaches have been approved for specific cancer treatments, while others are currently in preclinical and clinical trial stages. Given the success of immunotherapy, there has been a tremendous thrust to improve the clinical efficacy of various agents and strategies implemented so far. Here, we present a comprehensive overview of the development and clinical implementation of various immunotherapy approaches currently being used to treat cancer. We also highlight the latest developments, emerging trends, limitations, and future promises of cancer immunotherapy.

Pancreatic injury following immune checkpoint inhibitors: A systematic review and meta-analysis

Background: Pancreatic injury (pancreatitis, amylase/lipase elevation) is a rare adverse event of immune checkpoint inhibitors (ICIs). With the high number of clinical studies on ICIs, the incidence and characteristics of associated pancreatic injury (PI) need to be reevaluated.

Methods: A systematic review and meta-analysis was conducted to assess the incidence of PI in cancer patients who received ICIs in randomized controlled trials (RCTs). PubMed, Embase, the ASCO, ESMO, and AACR conference proceedings before 1 April 2022, were investigated for relevant research.

Results: 50 RCTs involving 35,223 patients were included. The incidence of ICIs-PI was 2.22% (95% CI = 1.94%–2.53%). The incidence of PI was 3.76% (95% CI = 1.84–7.67%) when combining two ICIs, which was higher than single ICIs [2.25% (95% CI = 1.91–2.65%)]. The ICIs were ranked from high to low based on PI incidence: PD-L1 inhibitors 3.01% (95% CI = 1.86–4.87%), CTLA-4 inhibitors 2.92% (95% CI = 0.99–8.65%) and PD-1 Inhibitor 2% (95% CI = 1.67–2.39%). The ICI with the highest rate of PI was pembrolizumab 7.23.% (95% CI = 1.69–30.89%). In addition, the incidence of severe ICIs-PI was 2.08% (95% CI = 1.76–2.46%); and the incidence of severe PI was 2.32% (95% CI = 1.76–3.06%) when combining two ICIs, which was higher than single ICI [1.95% (95% CI = 1.58–2.41%)]. The ICIs were ranked from high to low according to the incidence of severe PI: PD-L1 inhibitors 3.1% (95% CI = 1.7–5.64%), CTLA-4 inhibitors 2.69% (95% CI = 0.76–9.49%), PD-1 inhibitors 1.80% (95% CI = 1.41–2.29%).

Conclusion: Treatment with multiple ICIs result in a higher incidence of PI compared to single ICIs, irrespective of the grade of pancreatic injury. The incidence of PI caused by PD-L1 inhibitors is higher than that of CTLA-4 inhibitors and PD-1 Inhibitor, and Pembrolizumab has the highest rate of ICIs-PI. Although the incidence of ICIs-PI is not high, they are usually severe (≥ grade 3 events).

Ocular Inflammation Induced by Immune Checkpoint Inhibitors

Ocular immunotherapy-related adverse events (IRAEs), although rare, can be sight-threatening. Our objective was to analyze ocular IRAEs diagnosed in France from the marketing of immune checkpoint inhibitors (ICPIs) until June 2021 and to review the literature. We collected the cases of 28 patients (36 ocular IRAEs), occurring after an average of 17 weeks (±19). Forty-six percent of patients were treated for metastatic melanoma. Anti-PD1 agents were responsible for 57% of the IRAEs. Anterior uveitis was the most common (44%), followed by panuveitis (28%). Of 25 uveitis cases, 80% were bilateral and 60% were granulomatous. We found one case with complete Vogt-Koyanagi–Harada syndrome and one case of birdshot retinochoroidopathy. The other IRAEs were eight ocular surface disorders, one optic neuropathy, and one inflammatory orbitopathy. Seventy percent of the IRAEs were grade 3 according to the common terminology of AEs. ICPIs were discontinued in 60% of patients and 50% received local corticosteroids alone. The literature review included 230 uveitis cases, of which 7% were granulomatous. The distributions of ICPIs, cancer, and type of uveitis were similar to our cohort. Ocular IRAEs appeared to be easily controlled by local or systemic corticosteroids and did not require routine discontinuation of ICPIs. Further work is still warranted to define the optimal management of ocular IRAEs.

Integration of miRNA:mRNA Co-Expression Revealed Crucial Mechanisms Modulated in Immunogenic Cancer Cell Death

Immunogenic cell death (ICD) in cancer represents a functionally unique therapeutic response that can induce tumor-targeting immune responses. ICD is characterized by the exposure and release of numerous damage-associated molecular patterns (DAMPs), which confer adjuvanticity to dying cancer cells. The spatiotemporally defined emission of DAMPs during ICD has been well described, whereas the epigenetic mechanisms that regulate ICD hallmarks have not yet been deeply elucidated. Here, we aimed to examine the involvement of miRNAs and their putative targets using well-established in vitro models of ICD. To this end, B cell lymphoma (Mino) and breast cancer (MDA-MB-231) cell lines were exposed to two different ICD inducers, the combination of retinoic acid (RA) and interferon-alpha (IFN-α) and doxorubicin, and to non ICD inducers such as gamma irradiation. Then, miRNA and mRNA profiles were studied by next generation sequencing. Co-expression analysis identified 16 miRNAs differentially modulated in cells undergoing ICD. Integrated miRNA-mRNA functional analysis revealed candidate miRNAs, mRNAs, and modulated pathways associated with Immune System Process (GO Term). Specifically, ICD induced a distinctive transcriptional signature hallmarked by regulation of antigen presentation, a crucial step for proper activation of immune system antitumor response. Interestingly, the major histocompatibility complex class I (MHC-I) pathway was upregulated whereas class II (MHC-II) was downregulated. Analysis of MHC-II associated transcripts and HLA-DR surface expression confirmed inhibition of this pathway by ICD on lymphoma cells. miR-4284 and miR-212-3p were the strongest miRNAs upregulated by ICD associated with this event and miR-212-3p overexpression was able to downregulate surface expression of HLA-DR. It is well known that MHC-II expression on tumor cells facilitates the recruitment of CD4+ T cells. However, the interaction between tumor MHC-II and inhibitory coreceptors on tumor-associated lymphocytes could provide an immunosuppressive signal that directly represses effector cytotoxic activity. In this context, MHC-II downregulation by ICD could enhance antitumor immunity. Overall, we found that the miRNA profile was significantly altered during ICD. Several miRNAs are predicted to be involved in the regulation of MHC-I and II pathways, whose implication in ICD is demonstrated herein for the first time, which could eventually modulate tumor recognition and attack by the immune system.