LAG-3 as a Potent Target for Novel Anticancer Therapies of a Wide Range of Tumors

Progesterone receptor impairs immune respond and down-regulates sensitivity to anti-LAG3 in breast cancer

BACKGROUND

Progesterone receptor (PR) serves as a crucial prognostic and predictive marker in breast cancer. Nonetheless, the interplay between PR and the tumor immune microenvironment remains inadequately understood. This investigation employs bioinformatics analyses, mouse models, and clinical specimens to elucidate the impact of PR on immune microenvironment and identify potential targets for immunotherapy, furnishing valuable guidance for clinical practice.

METHODS

Analysis of immune infiltration score by Xcell between PR-positive and PR-negative breast cancer tumors. Construction of overexpression mouse progesterone receptor (mPgr) EMT-6 cell was to explore the tumor immune microenvironment. Furthermore, anti- Lymphocyte-activation gene 3 (LAG3) therapy aimed to investigate whether PR could influence the effectiveness of immune treatments.

RESULTS

Overexpression mPgr inhibited tumor growth in vitro, but promoted tumor growth in Balb/c mouse. Flow cytometry showed that the proportion and cytotoxicity of CD8+T cells in tumor of overexpressing mPgr group were significantly reduced. The significant reduction in overexpressing mPgr group was found in the proportions of LAG3+CD8+ T cells and LAG3+ Treg T cells. Anti-LAG3 treatment resulted in reduced tumor growth in EV group mouse rather than in overexpressing mPgr group. Patents derived tumor fragment (PDTF) also showed higher anti-tumor ability of CD3+T cell in patents' tumor with PR <20% after anti-human LAG3 treatment in vitro.

CONCLUSIONS

The mPgr promotes tumor growth by downregulating the infiltration and function of cytotoxic cell. LAG3 may be a target of ER-positive breast cancer immunotherapy. The high expression of PR hinders the sensitivity to anti-LAG3 treatment.

Efficient combination of radiotherapy and CAR-T - A systematic review

Chimeric antigen receptor T (CAR-T) cell therapy, a groundbreaking immunotherapy. However, it faces formidable challenges in treating solid tumors, grappling with issues like poor trafficking, limited penetration, and insufficient persistence within the tumor microenvironment (TME). CAR-T cells are engineered to express receptors that target specific cancer antigens, enhancing their ability to recognize and eliminate cancer cells. This review paper explores the intricate interplay between CAR-T therapy and radiotherapy (RT), investigating their synergistic potential. Radiotherapy, a standard cancer treatment, involves using high doses of radiation to target and damage cancer cells, disrupting their ability to grow and divide. We highlight that RT modulates the TME, augments antigen presentation, and promotes immune cell infiltration, bolstering CAR-T cell-mediated tumor eradication. Molecular insights shed light on RT-induced alterations in tumor stroma, T cell recruitment promotion, and induction of immunogenic cell death. Noteworthy, strategies, such as combining hypofractionated radiotherapy with myeloid-derived suppressor cell blockade, underscore innovative approaches to enhance CAR-T cell therapy in solid tumors. Bridging indications for RT and CAR-T cells in hematological malignancies are discussed, emphasizing scenarios where RT strategically enhances CAR-T cell efficacy. The paper critically evaluates the RT as a bridge compared to traditional chemotherapy, highlighting timing and dosage considerations crucial for optimizing CAR-T therapy outcomes. In summary, the paper provides valuable insights into the intricate molecular mechanisms activated by RT and innovative strategies to improve CAR-T cell therapy, fostering a deeper understanding of their combined potential in cancer treatment.

IRF8-driven reprogramming of the immune microenvironment enhances anti-tumor adaptive immunity and reduces immunosuppression in murine glioblastoma

Background

Glioblastoma (GBM) has a highly immunosuppressive tumor immune microenvironment (TIME), largely mediated by myeloid-derived suppressor cells (MDSCs). Here, we utilized a retroviral replicating vector (RRV) to deliver Interferon Regulatory Factor 8 (IRF8), a master regulator of type 1 conventional dendritic cell (cDC1) development, in a syngeneic murine GBM model. We hypothesized that RRV-mediated delivery of IRF8 could "reprogram" intratumoral MDSCs into antigen-presenting cells (APCs) and thereby restore T-cell responses.

Methods

Effects of RRV-IRF8 on survival and tumor growth kinetics were examined in the SB28 murine GBM model. Immunophenotype was analyzed by flow cytometry and gene expression assays. We assayed functional immunosuppression and antigen presentation by ex vivo T-cell-myeloid co-culture.

Results

Mice with RRV-IRF8 pre-transduced intracerebral tumors had significantly longer survival and slower tumor growth compared to controls. RRV-IRF8 treated tumors exhibited significant enrichment of cDC1s and CD8+ T-cells. Additionally, myeloid cells derived from RRV-IRF8 tumors showed decreased expression of the immunosuppressive markers Arg1 and IDO1 and demonstrated reduced suppression of naïve T-cell proliferation in ex vivo co-culture, compared to controls. Furthermore, DCs from RRV-IRF8 tumors showed increased antigen presentation compared to those from control tumors. In vivo treatment with azidothymidine (AZT), a viral replication inhibitor, showed that IRF8 transduction in both tumor and non-tumor cells is necessary for survival benefit, associated with a reprogrammed, cDC1- and CD8 T-cell-enriched TIME.

Conclusions

Our results indicate that reprogramming of glioma-infiltrating myeloid cells by in vivo expression of IRF8 may reduce immunosuppression and enhance antigen presentation, achieving improved tumor control.

Global research landscape and trends of cancer radiotherapy plus immunotherapy: A bibliometric analysis

The aim of this study was to present current research trends on the synergistic use of radiotherapy and immunotherapy (IRT) for cancer treatment. On March 1, 2023, we conducted a literature search for IRT papers using the Web of Science database. We extracted information and constructed two databases - the Core Database (CD) with 864 papers and Generalized Database (GD) with 6344 papers. A bibliometric analysis was performed to provide insights into the research landscape, to identify emerging trends and highly cited papers and journals in the field of IRT. The CD contained 864 papers that were collectively cited 31,818 times. Prominent journals in this area included the New England Journal of Medicine, Lancet Oncology, and the Journal of Clinical Oncology. Corresponding authors from the USA contributed the most publications. In recent years, lung cancer, melanoma, stereotactic radiotherapy, immune checkpoint inhibitors, and the tumor microenvironment emerged as hot research areas. This bibliometric analysis presented quantitative insights into research concerning IRT and proposed potential avenues for further exploration. Moreover, researchers can use our findings to select appropriate journals for publication or identify prospective collaborators. In summary, this bibliometric analysis provides a comprehensive overview of the historical progression and recent advancements in IRT research that may serve as inspiration for future investigations.

Immune checkpoint inhibitor-associated cardiovascular toxicities: A review

Immune checkpoint inhibitors (ICIs) have revolutionary effects on therapeutic strategies for multiple malignancies. Their efficacy depends on their ability to reactivate the host immune system to fight cancer cells. However, adverse reactions to ICIs are common and involve several organs, limiting their use in clinical practice. Although the incidence of cardiovascular toxicity is relatively low, it is associated with serious consequences and high mortality rates. The primary cardiovascular toxicities include myocarditis, pericarditis, Takotsubo syndrome, arrhythmia, vasculitis, acute coronary syndrome, and venous thromboembolism. Currently, the mechanism underlying ICI-associated cardiovascular toxicity remains unclear and underexplored. The diagnosis and monitoring of ICI-associated cardiovascular toxicities mainly include the following indicators: symptoms, signs, laboratory examination, electrocardiography, imaging, and pathology. Treatments are based on the grade of cardiovascular toxicity and mainly include drug withdrawal, corticosteroid therapy, immunosuppressants, and conventional cardiac treatment. This review focuses on the incidence, underlying mechanisms, clinical manifestations, diagnoses, and treatment strategies.

Exploring histological predictive biomarkers for immune checkpoint inhibitor therapy response in non-small cell lung cancer

Treatment challenges persist in advanced lung cancer despite the development of therapies beyond the traditional platinum-based chemotherapy. The early 2000s marked a shift to tyrosine kinase inhibitors targeting epidermal growth factor receptor, ushering in personalized genetic-based treatment. A further significant advance was the development of immune checkpoint inhibitors (ICIs), especially for non-small cell lung cancer. These target programmed death-ligand 1 (PD-L1) and cytotoxic T lymphocyte antigen 4, which enhanced the immune response against tumor cells. However, not all patients respond, and immune-related toxicities arise. This review emphasizes identifying biomarkers for ICI response prediction. While PD-L1 is a widely used, validated biomarker, its predictive accuracy is imperfect. Investigating tumor-infiltrating lymphocytes, tertiary lymphoid structure, and emerging biomarkers such as high endothelial venule, Human leukocyte antigen class I, T-cell immunoreceptors with Ig and ITIM domains, and lymphocyte activation gene-3 counts is promising. Understanding and exploring additional predictive biomarkers for ICI response are crucial for enhancing patient stratification and overall care in lung cancer treatment.

PYCR1, BANF1, and STARD8 Expression in Gastric Carcinoma: A Clinicopathologic, Prognostic, and Immunohistochemical Study

BACKGROUND

It will be important to understand the molecular pathways of gastric cancer (GC) occurrence and progression, thus detecting predictive and prognostic biomarkers of GC. Pyrroline-5-carboxylate reductase 1 (PYCR1) was upregulated in many cancers, suggesting its possible roles in carcinogenesis and tumor metastases. Barrier-of-autointegration factor 1 (BANF1) is a protein family that plays essential roles in maintaining the integrity of an intact cellular genome. Rho-GTPs are molecular switches that control many signal transduction pathways in normal cells, including 3 subgroups from 1 to 3 (DLC1-3). DLC-3, known as StAR-related lipid transfer domain protein 8 (STARD8), and its role in cancers were not sufficiently studied. The study aimed to investigate the significance of PYCR1, BANF1, and STARD8 protein expression in GC tissues and normal gastric mucosa retrieved from patients with GC to detect prognostic roles of expression.

PATIENTS AND METHODS

Specimens were collected from 100 patients with gastric carcinoma. After the application of the inclusion criteria of the study, we prepared 100 paraffin blocks from samples of the 100 included patients; each block included samples from gastric carcinoma and adjacent non-neoplastic gastric mucosa. We assessed the expression of PYCR1, BANF1, and STARD8 using immunohistochemistry in all studied samples. We followed patients for the detection of disease progression and survival rates. We correlate PYCR1, BANF1, and STARD8 expression with clinical, pathologic, and prognostic parameters.

RESULTS

Overexpression of PYCR1 and BANF1 and decreased expression of STARD8 was found in gastric carcinoma tissues than adjacent non-neoplastic gastric mucosa ( P <0.001), and was positively associated with high grade ( P =0.006), depth of tumor invasion, presence of lymph nodes metastases and advanced stage ( P =0.001), high incidence of GC progression, recurrence, unfavorable disease-free survival ( P =0.003) and unfavorable overall survival rates ( P <0.001). Thus, it was revealed that; in univariate and multivariate analyses, levels of PYCR1, BANF1, and STARD8 are associated with the overall survival rate of GC patients.

CONCLUSIONS

We showed that overexpression of PYCR1 and BANF1 and decreased expression of STARD8 in GC tissues was associated with poor prognosis and GC progression.

Immunohistochemical Expression of Immune Checkpoints; CTLA-4, LAG3, and TIM-3 in Cancer Cells and Tumor-infiltrating Lymphocytes (TILs) in Colorectal Carcinoma

BACKGROUND

Colorectal cancer is considered the third most prevalent cancer in both sexes. Immune checkpoint receptors that regulate T-cell response, stimulation, and development include lymphocyte activating gene 3 (LAG-3), cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), and T-cell immunoglobulin and mucin domain 3 (Tim-3). In addition, they are crucial for the advancement of cancer and tumor immune escape.

OBJECTIVE

This work's aim was to assess the immunohistochemistry expression of Tim-3, CTLA-4, and LAG-3 in cancer cells and tumor-infiltrating lymphocytes (TILs) in colorectal cancer (CRC) and the correlation between these markers and clinicopathological variables and survival data.

METHODS

This study involved 206 CRC specimens processed for CTLA-4, LAG3, and TIM-3 immunohistochemistry and correlated with the clinicopathological and survival parameters of the patients.

RESULTS

High CTLA-4 epithelial expression was highly related to the old age group, large tumor size, low tumor-stroma ratio (TSR), high grade, advanced stage, the presence of distant metastasis (DM), perineural invasion (PNI), necrosis, lymphovascular invasion (LVI), relapse, mortality, overall survival (OS), and disease-free survival (DFS), while negative CTLA-4 TILs expression was highly linked with the presence of gross perforation, low TSR, high tumor budding (TB) score, high grade, advanced stage, the existence of lymph node (LN) metastasis, DM, necrosis, LVI, PNI, DFS, mortality, and OS. Positive LAG-3 TILs expression was highly correlated with large tumor size, gross perforation, low TSR, high TB score, high grade, advanced phase, the presence of LN, necrosis, LVI, PNI, relapse DFS, mortality, and OS. High Tim-3 epithelial expression was extremely linked with low TSR, advanced phase, the presence of LN, LVI, PNI, relapse, DFS, mortality, and OS, while positive Tim-3 TILs expression was related to gross perforation, low TSR, high TB score, advanced stage, the presence of LN, DM, necrosis, relapse, DFS, mortality, and OS.

CONCLUSIONS

The patients' poor prognosis may be related to the immunohistochemistry expression of LAG-3, Tim-3, and CTLA-4 in CRC cancer tissue and TILs. Poor patient consequences can result from the CTLA-4, Tim-3, and LAG-3 co-expression, but CTLA-4 TILs' expression of these proteins may inhibit the growth of tumors.

Integrative analysis of LAG3 immune signature and identification of a LAG3-related genes prognostic signature in kidney renal clear cell carcinoma

Immune checkpoint blockade (ICB) therapy has resulted in improved overall survival in kidney renal clear cell carcinoma (KIRC), but most treated patients fail to show durable clinical responses. Lymphocyte activation gene-3 (LAG3) is a novel inhibitory immune checkpoint, but its expression pattern, prognostic value, and immunological role in KIRC remain unknown. In this study, we utilized TCGA_KIRC RNA-sequencing data to analyze the relationship between LAG3 expression and clinical features. The single-cell sequencing data and tissue immunofluorescence are employed to investigate the subcellular localization of LAG3 in KIRC. Kaplan-Meier plotter, TIMER, and TISIDB were used to assess the association between LAG3 expression and prognosis, as well as its correlation with immune-related components. We constructed the LAG3 interaction network by using STRING, GeneMANIA, BioGRID, and HitPredict databases. We found that LAG3 is upregulated and correlates with poor prognostic phenotype in KIRC. LAG3 is predominantly expressed on exhausted CD8+ T cells and shows strong co-expression with PDCD1 in KIRC. Moreover, our findings indicated that LAG3 not only inhibits T cell activation but also potentially regulates cell adhesion in KIRC. In conclusion, our study implies that LAG3 can serve as a potential prognostic biomarker for KIRC. Furthermore, blocking both LAG3 and PDCD1 may alleviate resistance to anti-PDCD1 therapy, providing novel insights for immunotherapy decision-making in KIRC patients.

Characterisation of the protein expression of the emerging immunotherapy targets VISTA, LAG-3 and PRAME in primary uveal melanoma: insights from a southern French patient cohort

Uveal melanoma (UM) is the most common intraocular tumour in adults, with dismal prognosis once metastases develop, since therapeutic options for the metastatic disease are ineffective. Over the past decade, novel cancer therapies based on immunotherapy have changed the landscape of treatment of different forms of cancer leading to many hopes of improvement in patient overall survival (OS). VISTA, LAG-3 and PRAME are novel promising targets of immunotherapy that have recently gained attention in different solid tumours, but whose relevance in UM remained to be comprehensively evaluated until now. Here, we studied the protein expression of VISTA, LAG-3 and PRAME using immunohistochemistry in representative whole tissue sections from primary UM cases in a cohort of 30 patients from a single centre (Nice University Hospital, Nice, France). The expression of each of these markers was correlated with different clinical and pathological parameters, including onset of metastases and OS. We demonstrated the protein expression of VISTA and LAG-3 in small lymphocytes infiltrating the tumour, while no expression of the proteins was detected in UM cells. For PRAME, nuclear expression was observed in UM cells, but no expression in tumour infiltrating immune cells was identified. Increased levels of VISTA expression in tumour infiltrating lymphocytes (TILs) were associated with nuclear BAP1 expression and better prognosis. Higher levels of LAG-3 in TILs were associated with higher levels of CD8-positive TILs. PRAME nuclear positivity in melanoma cells was associated with epithelioid cell dominant (>90%) UM histological subtype, higher mitotic numbers and a higher percentage of chromosome 8q gain. This study proposes VISTA as a novel relevant immune checkpoint molecule in primary UM and contributes to confirm LAG-3 and PRAME as potentially important immunotherapy targets in the treatment of UM patients, helping to expand the number of immunotherapy candidate molecules that are relevant to modulate in this aggressive cancer.

Comprehensive analysis of single-cell and bulk RNA-sequencing data identifies B cell marker genes signature that predicts prognosis and analysis of immune checkpoints expression in head and neck squamous cell carcinoma

Recent studies have shown that B cells and the associated tertiary lymphoid structures (TLS) correlate with the response of patients to immune checkpoint inhibitors (ICIs) and predict overall survival (OS) in cancer patients. We screened 145 B cell marker genes (BCMG) by a comprehensive analysis of single-cell RNA-sequencing (scRNA-seq) data of head and neck squamous cell carcinoma (HNSC) from the Gene Expression Omnibus (GEO) database. The BCMG signature (BCMGS) was established using The Cancer Genome Atlas (TCGA) dataset of HNSC and verified in four independent datasets. The multivariate Cox regression analysis identified the signature as an independent prognostic factor. A prognostic nomogram was constructed with independent prognostic factors using the TCGA dataset. GO and KEGG analysis revealed the underlying signaling pathways related to this signature. Study of immune profiles showed that patients in the low-risk group presented discriminative immune-cell infiltrations. Furthermore, the low-risk group was featured by higher TCR and BCR diversity, which suggested that low-risk patients may be more sensitive to ICIs. Immunohistochemistry was performed, and we found that high expression of FTH1 was significantly correlated with poor OS (P = 0.025). The expression of TIM-3, LAG-3 and PD-1 was positively correlated and associated with better OS in HNSC. However, there was no statistically significant difference between PD-L1, PD-L2, CTLA-4, TIGIT and prognosis. The BCMGS was a promising prognostic biomarker in HNSC, which may help to interpret the responses to immunotherapy and provide a new perspective for future research on the treatment in HNSC.

TIM-3 as a promising target for cancer immunotherapy in a wide range of tumors

T-cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) expression has been a trending topic in recent years due to its differential expression in a wide range of neoplasms. TIM-3 is one of the key immune checkpoint receptors that interact with GAL-9, PtdSer, HMGB1 and CEACAM1. Initially identified on the surface of T helper 1 (Th1) lymphocytes and later on cytotoxic lymphocytes (CTLs), monocytes, macrophages, natural killer cells (NKs), and dendritic cells (DCs), TIM-3 plays a key role in immunoregulation. Recently, a growing body of evidence has shown that its differential expression in various tumor types indicates a specific prognosis for cancer patients. Here, we discuss which types of cancer TIM-3 can serve as a prognostic factor and the influence of coexpressed immune checkpoint inhibitors, such as LAG-3, PD-1, and CTLA-4 on patients' outcomes. Currently, experimental medicine involving TIM-3 has significantly enhanced the anti-tumor effect and improved patient survival. In this work, we summarized clinical trials incorporating TIM-3 targeting monoclonal and bispecific antibodies in monotherapy and combination therapy and highlighted the emerging role of cell-based therapies.

Cancer cell-intrinsic PD-1: Its role in malignant progression and immunotherapy

Programmed cell death protein-1 (PD-1), also called CD279, is coded by the PDCD1 gene and is constitutively expressed on the surface of immune cells. As a receptor and immune checkpoint, PD-1 can bind to programmed death ligand-1/programmed death ligand-2 (PD-L1/PD-L2) in tumor cells, leading to tumor immune evasion. Anti-PD-1 and anti-PD-L1 are important components in tumor immune therapy. PD-1 is also expressed as an intrinsic variant (iPD-1) in cancer cells where it plays important roles in malignant progression as proposed by recent studies. However, iPD-1 has received much less attention compared to PD-1 expressed on immune cells although there is an unmet medical need for fully elucidating the mechanisms of actions to achieve the best response in tumor immunotherapy. iPD-1 suppresses tumorigenesis in non-small cell lung cancer (NSCLC) and colon cancer, whereas it promotes tumorigenesis in melanoma, hepatocellular carcinoma (HCC), pancreatic ductal adenocarcinoma (PDAC), thyroid cancer (TC), glioblastoma (GBM), and triple-negative breast cancer (TNBC). In this review, we focus on the role of iPD-1 in tumorigenesis and development and its molecular mechanisms. We also deeply discuss nivolumab-based combined therapy in common tumor therapy. iPD-1 may explain the different therapeutic effects of anti-PD-1 treatment and provide critical information for use in combined anti-tumor approaches.

Effects of Nanosecond Pulsed Electric Field on Immune Checkpoint Receptors in Melanoma Cells

Checkpoint molecules such as PD-1, LAG-3, and TIM-3 are currently under extensive investigation for their roles in the attenuation of the immune response in cancer. Various methods have been applied to overcome the challenges in this field. This study investigated the effects of nanosecond pulsed electric field (nsPEF) treatment on the expression of immune checkpoint molecules in A375 and C32 melanoma cells. The researchers found that the nsPEF treatment was able to enhance membrane permeabilization and morphological changes in the cell membrane without being cytotoxic. We found that the effects of nsPEFs on melanoma included (1) the transport of vesicles from the inside to the outside of the cells, (2) cell contraction, and (3) the migration of lipids from inside the cells to their peripheries. The treatment increased the expression of PD-1 checkpoint receptors. Furthermore, we also observed potential co-localization or clustering of MHC class II and PD-1 molecules on the cell surface and the secretion of cytokines such as TNF-α and IL-6. These findings suggest that nsPEF treatment could be a viable approach to enhance the delivery of therapeutic agents to cancer cells and to modulate the tumor microenvironment to promote an antitumor immune response. Further studies are needed to explore the mechanisms underlying these effects and their impacts on the antitumor immune response, and to investigate the potential of nsPEF treatment in combination with immune checkpoint inhibitors to improve clinical outcomes for cancer patients.

Targeting LAG-3, TIM-3, and TIGIT for cancer immunotherapy

In one decade, immunotherapy based on immune checkpoint blockades (ICBs) has become a new pillar of cancer treatment following surgery, radiation, chemotherapy, and targeted therapies. However, not all cancer patients benefit from single or combination therapy with anti-CTLA-4 and anti-PD-1/PD-L1 monoclonal antibodies. Thus, an increasing number of immune checkpoint proteins (ICPs) have been screened and their effectiveness evaluated in preclinical and clinical trials. Lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin and mucin-domain-containing-3 (TIM-3), and T cell immunoreceptor with immunoglobulin and tyrosine-based inhibitory motif (ITIM) domain (TIGIT) constitute the second wave of immunotherapy targets that show great promise for use in the treatment of solid tumors and leukemia. To promote the research and clinical application of ICBs directed at these targets, we summarize their discovery, immunotherapy mechanism, preclinical efficiency, and clinical trial results in this review.

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.

LAG-3 Inhibitors: Novel Immune Checkpoint Inhibitors Changing the Landscape of Immunotherapy

One of the most important steps forward in the management of cancer was the discovery of immunotherapy. It has become an essential pillar in the treatment paradigm of cancer patients. Unfortunately, despite the various options presented with immune checkpoint inhibitors (ICIs), the benefit is still limited to select patients and the vast majority of these patients gain either minimal benefit or eventually progress, leaving an unmet need for the development of novel therapeutic agents and strategies. Lymphocyte activation gene-3 (LAG-3), an immune checkpoint receptor protein, is a molecule found on the surface of activated T-cells. It plays a major role in negatively regulating T-cell function thereby providing tumors with an immune escape in the tumor microenvironment (TME). Given its importance in regulating the immune system, LAG-3 has been considered as a promising target in oncology and precision medicine. To date, two LAG-3-directed agents (eftilagimod alpha and relatlimab) have been approved in combination with programmed death-1 (PD-1) inhibitors in the setting of advanced solid tumors. In this review, we discuss the structure of LAG-3, its mechanism of action, and its interaction with its ligands. We also shed light on the emerging treatments targeting LAG-3 for the treatment of solid tumors.

Immune checkpoint inhibitors: maximizing benefit whilst minimizing toxicity

INTRODUCTION

The advent of immunotherapy has revolutionized the treatment of cancer; anti-tumor efficacy has been observed with immune checkpoint inhibitors (ICI) in ~20 different cancer types with durable responses in some cases. However, the risk of toxicity in the form of immune-related adverse events (irAE) partially counterbalances these benefits, and there are no FDA-approved biomarkers to categorize patients by likelihood of response or risk of irAEs.

AREAS COVERED

We conducted a thorough review of the literature of clinical studies regarding ICI and their toxicities. In this review, we synthesize the current body of literature about ICI treatment and irAE by summarizing the classes and uses of ICI, how to identify patients at risk for irAE, present the current understanding of irAE development, describe ongoing research into biomarkers of irAE, examine opportunities for irAE prevention, described management of steroid refractory irAE, and highlight future directions for development of prevention and management strategies.

EXPERT OPINION

While ongoing biomarker studies are promising, it is unlikely that there will be a 'one-size-fits-all' approach to categorizing irAE risk. In contrast, improved management and irAE prophylaxis are potentially in reach, and ongoing trials will help elucidate best practices.

The Changing Landscape of Immunotherapy for Advanced Renal Cancer

The management of advanced renal cell carcinoma has advanced tremendously over the past decade, but most patients still do not receive durable clinical benefit from current therapies. Renal cellcarcinoma is an immunogenic tumor, historically with conventional cytokine therapies, such as interleukin-2 and interferon-α, and contemporarily with the introduction of immune checkpoint inhibitors. Now the central therapeutic strategy in renal cell carcinoma is combination therapies including immunecheckpoint inhibitors. In this Review, we look back on the historical changes in systemic therapy for advanced renal cell carcinoma, and focus on the latest developments and prospects in this field.

Immune-checkpoint inhibitor resistance in cancer treatment: Current progress and future directions

Cancer treatment has been advanced with the advent of immune checkpoint inhibitors (ICIs) exemplified by anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), anti-programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) drugs. Patients have reaped substantial benefit from ICIs in many cancer types. However, few patients benefit from ICIs whereas the vast majority undergoing these treatments do not obtain survival benefit. Even for patients with initial responses, they may encounter drug resistance in their subsequent treatments, which limits the efficacy of ICIs. Therefore, a deepening understanding of drug resistance is critically important for the explorations of approaches to reverse drug resistance and to boost ICI efficacy. In the present review, different mechanisms of ICI resistance have been summarized according to the tumor intrinsic, tumor microenvironment (TME) and host classifications. We further elaborated corresponding strategies to battle against such resistance accordingly, which include targeting defects in antigen presentation, dysregulated interferon-γ (IFN-γ) signaling, neoantigen depletion, upregulation of other T cell checkpoints as well as immunosuppression and exclusion mediated by TME. Moreover, regarding the host, several additional approaches that interfere with diet and gut microbiome have also been described in reversing ICI resistance. Additionally, we provide an overall glimpse into the ongoing clinical trials that utilize these mechanisms to overcome ICI resistance. Finally, we summarize the challenges and opportunities that needs to be addressed in the investigation of ICI resistance mechanisms, with the aim to benefit more patients with cancer.

Scientific Discoveries Supporting Theories in Science: From Thinking to Practice

The idea to propose this ambitious title for a Special Issue in the International Journal of Molecular Science came, on one hand, from my personal experience in research in medicine, lasting 41 years, which has often been inspired by chance [...].

Galectin-3 Is a Natural Binding Ligand of MCAM (CD146, MUC18) in Melanoma Cells and Their Interaction Promotes Melanoma Progression

Melanoma cell adhesion molecule (MCAM, CD146, MUC18) is a heavily glycosylated transmembrane protein and a marker of melanoma metastasis. It is expressed in advanced primary melanoma and metastasis but rarely in benign naevi or normal melanocytes. More and more evidence has shown that activation of the MCAM on cell surface plays a vital role in melanoma progression and metastasis. However, the natural MCAM binding ligand that initiates MCAM activation in melanoma so far remains elusive. This study revealed that galectin-3, a galactoside-binding protein that is commonly overexpressed in many cancers including melanoma, is naturally associated with MCAM on the surface of both skin and uveal melanoma cells. Binding of galectin-3 to MCAM, via O-linked glycans on the MCAM, induces MCAM dimerization and clustering on cell surface and subsequent activation of downstream AKT signalling. This leads to the increases of a number of important steps in melanoma progression of cell proliferation, adhesion, migration, and invasion. Thus, galectin-3 is a natural binding ligand of MCAM in melanoma, and their interaction activates MCAM and promotes MCAM-mediated melanoma progression. Targeting the galectin-3–MCAM interaction may potentially be a useful therapeutic strategy for melanoma treatment.