Tim-3 expression represents dysfunctional tumor infiltrating T cells in renal cell carcinoma

Simultaneous targeting of Tim3 and A2a receptors modulates MSLN-CAR T cell antitumor function in a human cervical tumor xenograft model

Introduction

Chimeric antigen receptor (CAR) T cell therapy has transformed the treatment of hematological malignancies. However, its efficacy in solid tumors is limited by the immunosuppressive tumor microenvironment that compromises CAR T cell antitumor function in clinical settings. To overcome this challenge, researchers have investigated the potential of inhibiting specific immune checkpoint receptors, including A2aR (Adenosine A2 Receptor) and Tim3 (T cell immunoglobulin and mucin domain-containing protein 3), to enhance CAR T cell function. In this study, we evaluated the impact of genetic targeting of Tim3 and A2a receptors on the antitumor function of human mesothelin-specific CAR T cells (MSLN-CAR) in vitro and in vivo.

Methods

Second-generation anti-mesothelin CAR T cells were produced using standard cellular and molecular techniques. A2aR-knockdown and/or Tim3- knockdown anti-mesothelin-CAR T cells were generated using shRNA-mediated gene silencing. The antitumor function of CAR T cells was evaluated by measuring cytokine production, proliferation, and cytotoxicity in vitro through coculture with cervical cancer cells (HeLa cell line). To evaluate in vivo antitumor efficacy of manufactured CAR T cells, tumor growth and mouse survival were monitored in a human cervical cancer xenograft model.

Results

In vitro experiments demonstrated that knockdown of A2aR alone or in combination with Tim3 significantly improved CAR T cell proliferation, cytokine production, and cytotoxicity in presence of tumor cells in an antigen-specific manner. Furthermore, in the humanized xenograft model, both double knockdown CAR T cells and control CAR T cells could effectively control tumor growth. However, single knockdown CAR T cells were associated with reduced survival in mice.

Conclusion

These findings highlight the potential of concomitant genetic targeting of Tim3 and A2a receptors to augment the efficacy of CAR T cell therapy in solid tumors. Nevertheless, caution should be exercised in light of our observation of decreased survival in mice treated with single knockdown MSLN-CAR T cells, emphasizing the need for careful efficacy considerations.

Immune checkpoint inhibitors associated cardiovascular immune-related adverse events

Immune checkpoint inhibitors (ICIs) are specialized monoclonal antibodies (mAbs) that target immune checkpoints and their ligands, counteracting cancer cell-induced T-cell suppression. Approved ICIs like cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1), its ligand PD-L1, and lymphocyte activation gene-3 (LAG-3) have improved cancer patient outcomes by enhancing anti-tumor responses. However, some patients are unresponsive, and others experience immune-related adverse events (irAEs), affecting organs like the lung, liver, intestine, skin and now the cardiovascular system. These cardiac irAEs include conditions like myocarditis, atherosclerosis, pericarditis, arrhythmias, and cardiomyopathy. Ongoing clinical trials investigate promising alternative co-inhibitory receptor targets, including T cell immunoglobulin and mucin domain-containing protein 3 (Tim-3) and T cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT). This review delves into the mechanisms of approved ICIs (CTLA-4, PD-1, PD-L1, and LAG-3) and upcoming options like Tim-3 and TIGIT. It explores the use of ICIs in cancer treatment, supported by both preclinical and clinical data. Additionally, it examines the mechanisms behind cardiac toxic irAEs, focusing on ICI-associated myocarditis and atherosclerosis. These insights are vital as ICIs continue to revolutionize cancer therapy, offering hope to patients, while also necessitating careful monitoring and management of potential side effects, including emerging cardiac complications.

Emerging Immunotherapy Approaches for Advanced Clear Cell Renal Cell Carcinoma

The most common subtype of renal cell carcinoma is clear cell renal cell carcinoma (ccRCC). While localized ccRCC can be cured with surgery, metastatic disease has a poor prognosis. Recently, immunotherapy has emerged as a promising approach for advanced ccRCC. This review provides a comprehensive overview of the evolving immunotherapeutic landscape for metastatic ccRCC. Immune checkpoint inhibitors (ICIs) like PD-1/PD-L1 and CTLA-4 inhibitors have demonstrated clinical efficacy as monotherapies and in combination regimens. Combination immunotherapies pairing ICIs with antiangiogenic agents, other immunomodulators, or novel therapeutic platforms such as bispecific antibodies and chimeric antigen receptor (CAR) T-cell therapy are areas of active research. Beyond the checkpoint blockade, additional modalities including therapeutic vaccines, cytokines, and oncolytic viruses are also being explored for ccRCC. This review discusses the mechanisms, major clinical trials, challenges, and future directions for these emerging immunotherapies. While current strategies have shown promise in improving patient outcomes, continued research is critical for expanding and optimizing immunotherapy approaches for advanced ccRCC. Realizing the full potential of immunotherapy will require elucidating mechanisms of response and resistance, developing predictive biomarkers, and rationally designing combination therapeutic regimens tailored to individual patients. Advances in immunotherapy carry immense promise for transforming the management of metastatic ccRCC.

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.

Immunobiology and Metabolic Pathways of Renal Cell Carcinoma

The treatment of advanced renal cell carcinoma (RCC) has changed dramatically with immune checkpoint inhibitors, yet most patients do not have durable responses. There is consequently a tremendous need for novel therapeutic development. RCC, and particularly the most common histology clear cell RCC, is an immunobiologically and metabolically distinct tumor. An improved understanding of RCC-specific biology will be necessary for the successful identification of new treatment targets for this disease. In this review, we discuss the current understanding of RCC immune pathways and metabolic dysregulation, with a focus on topics important for future clinical development.

Emerging resistance vs. losing response to immune check point inhibitors in renal cell carcinoma: two differing phenomena

The introduction of immune checkpoint inhibitor (ICI) has revolutionized the treatment of metastatic renal cell carcinoma (mRCC) and has dramatically improved the outcomes of patients. The use of monotherapy or combinations of ICIs targeting PD-1/PD-L1 and CTLA-4, as well as the addition of ICIs with tyrosine kinase inhibitors, has significantly enhanced the overall survival of mRCC patients. Despite these promising results, there remains a subset of patients who either do not respond to treatment (primary resistance) or develop resistance to therapy over time (acquired resistance). Understanding the mechanisms underlying the development of resistance to ICI treatment is crucial in the management of mRCC, as they can be used to identify new targets for innovative therapeutic strategies. Currently, there is an unmet need to develop new predictive and prognostic biomarkers that can aid in the development of personalized treatment options for mRCC patients. In this review, we summarize several mechanisms of ICI resistance in RCC, including alterations in tumor microenvironment, upregulation of alternative immune checkpoint pathways, and genetic and epigenetic changes. Additionally, we highlight potential strategies that can be used to overcome resistance, such as combination therapy, targeted therapy, and immune modulation.

Biomarkers for Immune Checkpoint Inhibitors in Renal Cell Carcinoma

Immune checkpoint inhibitor (ICI) therapy has revolutionized renal cell carcinoma treatment. Patients previously thought to be palliative now occasionally achieve complete cures from ICI. However, since immunotherapies stimulate the immune system to induce anti-tumor immunity, they often lead to adverse autoimmunity. Furthermore, some patients receive no benefit from ICI, thereby unnecessarily risking adverse events. In many tumor types, PD-L1 expression levels, immune infiltration, and tumor mutation burden predict the response to ICI and help inform clinical decision making to better target ICI to patients most likely to experience benefits. Unfortunately, renal cell carcinoma is an outlier, as these biomarkers fail to discriminate between positive and negative responses to ICI therapy. Emerging biomarkers such as gene expression profiles and the loss of pro-angiogenic proteins VHL and PBRM-1 show promise for identifying renal cell carcinoma cases likely to respond to ICI. This review provides an overview of the mechanistic underpinnings of different biomarkers and describes the theoretical rationale for their use. We discuss the effectiveness of each biomarker in renal cell carcinoma and other cancer types, and we introduce novel biomarkers that have demonstrated some promise in clinical trials.

Combined Immune Checkpoint Blockade Enhances Antiviral Immunity against Bovine Leukemia Virus

Bovine leukemia virus (BLV) is a retrovirus that causes enzootic bovine leukosis (EBL) in cattle and is widespread in many countries, including Japan. Recent studies have revealed that the expression of immunoinhibitory molecules, such as programmed death-1 (PD-1) and PD-ligand 1, plays a critical role in immunosuppression and disease progression during BLV infection. In addition, a preliminary study has suggested that another immunoinhibitory molecule, T-cell immunoglobulin domain and mucin domain-3 (TIM-3), is involved in immunosuppression during BLV infection. Therefore, this study was designed to further elucidate the immunoinhibitory role of immune checkpoint molecules in BLV infection. TIM-3 expression was upregulated on peripheral CD4⁺ and CD8⁺ T cells in BLV-infected cattle. Interestingly, in EBL cattle, CD4⁺ and CD8⁺ T cells infiltrating lymphomas expressed TIM-3. TIM-3 and PD-1 were upregulated and coexpressed in peripheral CD4⁺ and CD8⁺ T cells from BLV-infected cattle. Blockade by anti-bovine TIM-3 monoclonal antibody increased CD69 expression on T cells and gamma interferon (IFN-γ) production from peripheral blood mononuclear cells from BLV-infected cattle. A syncytium formation assay also demonstrated the antiviral effects of TIM-3 blockade against BLV infection. The combined inhibition of TIM-3 and PD-1 pathways significantly enhanced IFN-γ production and antiviral efficacy compared to inhibition alone. In conclusion, the combined blockade of TIM-3 and PD-1 pathways shows strong immune activation and antiviral effects and has potential as a novel therapeutic method for BLV infection. IMPORTANCE Enzootic bovine leukosis caused by bovine leukemia virus (BLV) is an important viral disease in cattle, causing severe economic losses to the cattle industry worldwide. The molecular mechanisms of BLV-host interactions are complex. Previously, it was found that immune checkpoint molecules, such as PD-1, suppress BLV-specific Th1 responses as the disease progresses. To date, most studies have focused only on how PD-1 facilitates escape from host immunity in BLV-infected cattle and the antiviral effects of the PD-1 blockade. In contrast, how T-cell immunoglobulin domain and mucin domain-3 (TIM-3), another immune checkpoint molecule, regulates anti-BLV immune responses is rarely reported. It is also unclear why PD-1 inhibition alone was insufficient to exert anti-BLV effects in previous clinical studies. In this study, the expression profile of TIM-3 in T cells derived from BLV-infected cattle suggested that TIM-3 upregulation is a cause of immunosuppression in infected cattle. Based on these results, anti-TIM-3 antibody was used to experimentally evaluate its function in influencing immunity against BLV. Results indicated that TIM-3 upregulation induced by BLV infection suppressed T-cell activation and antiviral cytokine production. Some T cells coexpressed PD-1 and TIM-3, indicating that simultaneous inhibition of PD-1 and TIM-3 with their respective antibodies synergistically restored antiviral immunity. This study could open new avenues for treating bovine chronic infections.

Technology meets TILs: Deciphering T cell function in the -omics era

T cells are at the center of cancer immunology because of their ability to recognize mutations in tumor cells and directly mediate cancer cell killing. Immunotherapies to rejuvenate exhausted T cell responses have transformed the clinical management of several malignancies. In parallel, the development of novel multidimensional analysis platforms, such as single-cell RNA sequencing and high-dimensional flow cytometry, has yielded unprecedented insights into immune cell biology. This convergence has revealed substantial heterogeneity of tumor-infiltrating immune cells in single tumors, across tumor types, and among individuals with cancer. Here we discuss the opportunities and challenges of studying the complex tumor microenvironment with -omics technologies that generate vast amounts of data, highlighting the opportunities and limitations of these technologies with a particular focus on interpreting high-dimensional studies of CD8+ T cells in the tumor microenvironment.

Spatial distribution and functional analysis define the action pathway of Tim-3/Tim-3 ligands in tumor development

The spatial organization of immune cells within the tumor microenvironment (TME) largely determines the anti-tumor immunity and also highly predicts tumor progression and therapeutic response. Tim-3 is a well-accepted immune checkpoint and plays multifaceted immunoregulatory roles via interaction with distinct Tim-3 ligands (Tim-3L), showing great potential as an immunotherapy target. However, the cell sociology mediated by Tim-3/Tim-3L and their contribution to tumor development remains elusive. Here, we analyzed the spatial distribution of Tim-3/Tim-3L in TME using multiplex fluorescence staining and revealed that despite the increased Tim-3 expression in various tumor-infiltrated lymphocytes, Tim-3⁺CD4⁺ cells were more accumulated in parenchymal/tumor region compared with stromal region and exhibited more close association with patient survival. Strikingly, CD4 T cells surrounding Tim-3L⁺ cells expressed higher Tim-3 than other cells in cancerous tissues. In vivo studies confirmed that depletion of CD4 T cells completely abrogated the inhibition of tumor growth and metastasis, as well as the functional improvement of CD8 T and NK, mediated by Tim-3 blockade, which was further validated in peripheral lymphocytes from patients with hepatocellular carcinoma. In conclusion, our findings unravel the importance of CD4 T cells in Tim-3/Tim-3L-mediated immunosuppression and provide new thoughts for Tim-3 targeted cancer immunotherapy.

Soluble Tim-3/Gal-9 as predictors of adverse outcomes after kidney transplantation: a cohort study

BACKGROUND

In our previous study, serum soluble T-cell immunoglobulin and mucin structure-3 (stim-3) and galactosin-9 (sGal-9) were found to be associated with renal function after kidney transplantation. However, it is unclear whether these two indicators can predict adverse outcomes after transplantation.

METHODS

Ninety-one recipients of kidney transplantation were enrolled and divided into a stable group and an adverse outcome group (consisting of biopsy-proven rejection, graft loss, death and clinically diagnosed rejection). The expression levels of sTim-3 and sGal-9 before (pre-Tim-3 and pre-Gal-9) and one month after transplantation (post-Tim-3 and post-Gal-9) were measured by ELISA.

RESULTS

The level of pre-Tim-3 was significantly higher in the stable group than in the adverse outcome group [median (range), 2275 (840-4236) pg/mL vs. 1589 (353-3094) pg/mL, P=0.002]. The level of post-Gal-9 was significantly lower in the stable group than in the adverse outcome group [median (range), 4869 (1418-13080) pg/mL vs. 6852: (4128-10760) pg/mL, P=0.003]. The areas under the curve (AUCs) for pre-Tim-3 and post-Gal-9 were 0.737 (P=0.002) and 0.751 (P=0.003), respectively, better than AUC of post-eGFR (0.633) (P=0.071), according to the receiver operating characteristic (ROC) curve. Through Cox regression analysis, including pre-Tim-3, post-Gal-9, post-eGFR, sex, age, BMI of recipients and donors, pre-Tim-3 and post-Gal-9 were independent risk factors for adverse outcomes after kidney transplantation (P=0.016, P=0.033, respectively).

CONCLUSION

Serum sTim-3 and sGal-9 can predict adverse outcomes within two years after kidney transplantation.

The roles of exosomal immune checkpoint proteins in tumors

Targeting immune checkpoints has achieved great therapeutic effects in the treatment of early-stage tumors. However, most patients develop adaptive resistance to this therapy. The latest evidence demonstrates that tumor-derived exosomes may play a key role in systemic immune suppression and tumor progression. In this article, we highlight the role of exosomal immune checkpoint proteins in tumor immunity, with an emphasis on programmed death ligand 1 (PD-L1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), as well as emerging evidence on roles of T cell immunoglobulin-3 (TIM-3), arginase 1 (ARG1), and estrogen receptor binding fragment-associated antigen 9 (EBAG9) expressed by exosomes.

Characterization of Molecular Heterogeneity Associated With Tumor Microenvironment in Clear Cell Renal Cell Carcinoma to Aid Immunotherapy

Clear cell renal cell carcinoma (ccRCC) is the most common type of kidney cancer and has strong immunogenicity. A systematically investigation of the tumor microenvironment (TME) in ccRCC could contribute to help clinicians develop personalized treatment and facilitate clinical decision-making. In this study, we analyzed the immune-related subtype of ccRCC on the basis of immune-related gene expression data in The Cancer Genome Atlas (TCGA, N = 512) and E-MTAB-1980 (N = 101) dataset, respectively. As a result, two subtypes (C1 and C2) were identified by performing non-negative matrix factorization clustering. Subtype C1 was characterized by increased advance ccRCC cases and immune-related pathways. A higher immune score, stromal score, TMB value, Tumor Immune Dysfunction and Exclusion (TIDE) prediction score, and immune checkpoint genes expression level were also observed in C1. In addition, the C1 subtype might benefit from chemotherapy and immunotherapy. The patients in subtype C2 had more metabolism-related pathways, higher tumor purity, and a better prognosis. Moreover, some small molecular compounds for the treatment of ccRCC were identified between the two subtypes by using the Connectivity Map (CMap) database. Finally, we constructed and validated an immune-related (IR) score to evaluate immune modification individually. A high IR score corresponded to a favorable prognosis compared to a low IR score, while more advanced tumor stage and grade cases were enriched in the low IR score group. The two IR score groups also showed a distinct divergence among immune status, TME, and chemotherapy. The external validation dataset (E-MTAB-1980) and another immunotherapy cohort (IMvigor 210) demonstrated that patients in the high IR score group had a significantly prolonged survival time and clinical benefits compared to the low IR score group. Together, characterization of molecular heterogeneity and IR signature may help develop new insights into the TME of ccRCC and provide new strategies for personalized treatment.

Nanobodies Enhancing Cancer Visualization, Diagnosis and Therapeutics

Worldwide, cancer is a serious health concern due to the increasing rates of incidence and mortality. Conventional cancer imaging, diagnosis and treatment practices continue to substantially contribute to the fight against cancer. However, these practices do have some risks, adverse effects and limitations, which can affect patient outcomes. Although antibodies have been developed, successfully used and proven beneficial in various oncology practices, the use of antibodies also comes with certain challenges and limitations (large in size, poor tumor penetration, high immunogenicity and a long half-life). Therefore, it is vital to develop new ways to visualize, diagnose and treat cancer. Nanobodies are novel antigen-binding fragments that possess many advantageous properties (small in size, low immunogenicity and a short half-life). Thus, the use of nanobodies in cancer practices may overcome the challenges experienced with using traditional antibodies. In this review, we discuss (1) the challenges with antibody usage and the superior qualities of nanobodies; (2) the use of antibodies and nanobodies in cancer imaging, diagnosis, drug delivery and therapy (surgery, radiotherapy, chemotherapy and immunotherapy); and (3) the potential improvements in oncology practices due to the use of nanobodies as compared to antibodies.

Targeted knockdown of Tim3 by short hairpin RNAs improves the function of anti-mesothelin CAR T cells

T-cell immunoglobulin mucin 3 (Tim3) is an immune checkpoint receptor that plays a central role in chimeric antigen receptor (CAR) T cell exhaustion within the tumor microenvironment. This study was aimed to evaluate the effects of targeted-knockdown of Tim3 on the antitumor function of anti-mesothelin (MSLN)-CAR T cells. To knockdown Tim3 expression, three different shRNA sequences specific to different segments of the human Tim3 gene were designed and co-inserted with an anti-MSLN-CAR transgene into lentiviral vectors. To investigate the efficacy of Tim3 targeting in T cells, expression of Tim3 was assessed before and after antigen stimulation. Afterwards, cytotoxic effects, proliferative response and cytokine production of MSLN-CAR T cells and Tim3-targeted MSLN-CAR T cells were analyzed. Our results showed that activation of T cells and MSLN-CAR T cells led to up-regulation of Tim3. Tim3 knockdown significantly decreased its expression in different groups of MSLN-CAR T cells. Tim3 knockdown significantly improved cytotoxic function, cytokine production and proliferation capacity of MSLN-CAR T cells. Our findings indicate that targeted knockdown of Tim3 allows tumor-infiltrating CAR T cells that would otherwise be inactivated to continue to expand and carry out effector functions, thereby altering the tumor microenvironment from immunosuppressive to immunosupportive via mitigated Tim3 signaling.

PAX5 haploinsufficiency induced CD8+ T cells dysfunction or exhaustion by high expression of immune inhibitory-related molecules

PURPOSE

PAX5 haploinsufficiency promoting tumorigenesis is related to immune escape. But the mechanisms of PAX5 mutations inducing tumor immune escape have not been clarified. Our aim was to study how PAX5 haploinsufficiency influences effector CD8 + T cells in tumor microenvironment.

METHODS

We estimated the proportions of 22 immune cell types and the expressions of immune inhibitory-related molecules based on gene expression profiles (GEPs) from children's B- acute lymphoblastic leukemia(B-ALL) with PAX5 mutations by CIBERSORT, an established algorithm. We constructed the PAX5 haplodeletion A20 cell lines, built allografted A20 tumor models and evaluated the effect of PAX5 haplodeletion on immune inhibitory-related molecules in the tumor microenvironment (TME).

RESULTS

Our results indicated the percentages of T cells in bone marrow of children's B-ALL with PAX5 mutations were not statistically different from that in bone marrow of B-ALL without PAX5 mutations, except for T follicular helper (Tfh) cells. But a variety of up-regulated immune inhibitory-related molecules in bone marrow of children's B- ALL with PAX5 mutations were identified. By different approaches, we found that several immune inhibitory-related molecules of CD8+ T cells in TME of PAX5 haplodeletion clones such as TIM3, NR4A1 and BATF, were increased significantly compared with that of PAX5 wild type control. The IFN-ɤ of CD8+ T cells in TME of PAX5 haplodeletion tumors was decreased significantly compared with that of PAX5 wild type control.

CONCLUSION

Our study showed that PAX5 haploinsufficiency induced CD8+ T cells dysfunction or exhaustion by high expression of TIM3, NR4A1 and BATF in the CD8+ T cells of TME.

Can Immune Suppression and Epigenome Regulation in Placenta Offer Novel Insights into Cancer Immune Evasion and Immunotherapy Resistance?

Cancer is the second leading cause of mortality and morbidity in the developed world. Cancer progression involves genetic and epigenetic alterations, accompanied by aggressive changes, such as increased immune evasion, onset of metastasis, and drug resistance. Similar to cancer, DNA hypomethylation, immune suppression, and invasive cell behaviours are also observed in the human placenta. Mechanisms that lead to the acquisition of invasive behaviour, immune evasion, and drug and immunotherapy resistance are presently under intense investigations to improve patient outcomes. Here, we review current knowledge regarding the similarities between immune suppression and epigenome regulation, including the expression of repetitive elements (REs), endogenous retroviruses (ERVs) and transposable elements (TEs) in cells of the placenta and in cancer, which are associated with changes in immune regulation and invasiveness. We explore whether immune suppression and epigenome regulation in placenta offers novel insights into immunotherapy resistance in cancer, and we also discuss the implications and the knowledge gaps relevant to these findings, which are rapidly being accrued in these quite disparate research fields. Finally, we discuss potential linkages between TE, ERV and RE activation and expression, regarding mechanisms of immune regulation in placenta and cancer. A greater understanding of the role of immune suppression and associated epigenome regulation in placenta could help to elucidate some comparable mechanisms operating in cancer, and identify potential new therapeutic targets for treating cancer.

Integrated analysis of immune-related gene subtype and immune index for immunotherapy in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common type of renal cell carcinoma (RCC) with high immunogenicity. Research on immune-related gene (IRG) is of great significance in ccRCC in identifying new therapeutic targets and improving patient prognosis. In this study, the IRG patterns of ccRCC were investigated and correlated these patterns with tumor microenvironment infiltrating characteristics in immunotherapy. Moreover, an IRG score was constructed to quantify the pattern of individual tumors through the principal component analysis algorithm. Two distinct molecular subtypes (C1 and C2) were identified based on the IRGs expression profile. Subtype C1 was characterized with significantly high level of immune-checkpoint, immune score, stromal score, showed high drug sensitivity in Sorafenib, Sunitinib, Cisplatin, Vinblastine, Vinorelbine, Vorinostat, and Gemcitabine. Cytokine-cytokine receptor pathway, chemokine signaling pathway, and JAK signaling pathways were found enriched in the subtype C1 account for the poor prognosis. Subtype C2 was linked to a better survival outcome. By using the Connective Map database, subtype specific small molecular drugs identified that could facilitate the treatment of ccRCC patients. In addition, A immune index that used to evaluated the immune modification patterns and further validated in the other types RCC dataset, such as papillary renal cell carcinoma (pRCC) and chromophobe renal cell carcinoma (chRCC). Together, this study identified two distinct molecular subtypes with immune index, aid to the treatment of ccRCC and enhancing our cognition of the tumor microenvironment infiltration characterization in ccRCC immunotherapy.

Beyond conventional immune-checkpoint inhibition - novel immunotherapies for renal cell carcinoma

The management of advanced-stage renal cell carcinoma (RCC) has been transformed by the development of immune-checkpoint inhibitors (ICIs). Nonetheless, most patients do not derive durable clinical benefit from these agents. Importantly, unlike other immunotherapy-responsive solid tumours, most RCCs have only a moderate mutational burden, and paradoxically, high levels of tumour CD8+ T cell infiltration are associated with a worse prognosis in patients with this disease. Building on the successes of antibodies targeting the PD-1 and CTLA4 immune checkpoints, multiple innovative immunotherapies are now in clinical development for the treatment of patients with RCC, including ICIs with novel targets, co-stimulatory pathway agonists, modified cytokines, metabolic pathway modulators, cell therapies and therapeutic vaccines. However, the successful development of such novel immune-based treatments and of immunotherapy-based combinations will require a disease-specific framework that incorporates a deep understanding of RCC immunobiology. In this Review, using the structure provided by the well-described cancer-immunity cycle, we outline the key steps required for a successful antitumour immune response in the context of RCC, and describe the development of promising new immunotherapies within the context of this framework. With this approach, we summarize and analyse the most encouraging targets of novel immune-based therapies within the RCC microenvironment, and review the landscape of emerging antigen-directed therapies for this disease.

Tumor-infiltrating CD8+ T cell antitumor efficacy and exhaustion: molecular insights

Host immunity has an essential role in the clinical management of cancers. Therefore, it is advantageous to choose therapies that can promote tumor cell death and concurrently boost host immunity. The dynamic tumor microenvironment (TME) determines whether an antineoplastic drug will elicit favorable or disparaging immune responses from tumor-infiltrating lymphocytes (TILs). CD8+ T cells are one of the primary tumor-infiltrating immune cells that deliver antitumor responses. Here, we review the influence of various factors in the TME on CD8+ T cell exhaustion and survival, and possible strategies for restoring CD8+ T cell effector function through immunotherapy.

Low Distribution of TIM-3+ Cytotoxic Tumor-Infiltrating Lymphocytes Predicts Poor Outcomes in Gastrointestinal Stromal Tumors

There are multiple tumor-infiltrating lymphocytes (TILs) and relevant immune checkpoints existing in gastrointestinal stromal tumor (GIST), which provides opportunities and rationales for developing effective immunotherapies. Recent studies have suggested that checkpoint TIM-3/Gal-9 plays a pivotal role on immune response in multiple tumors, similar to the PD-1/PD-L1, emerging as a potential therapeutic target. However, their functions in GIST are unrevealed. Hence, the expression of immune checkpoints TIM-3 and Gal-9, as well as the infiltration of CD8⁺ T cells and NK cells, is described in 299 cases of GIST specimens. The results showed that TIM-3 and Gal-9 are mainly expressed in TILs, rarely in tumor cells. Expression levels of TIM-3 and Gal-9 significantly differ in varying risks of GIST and exert opposite distribution trends. Indicated by prognosis analysis, high TIM-3 expression of TILs was associated with improved outcome, while low expression levels of TIM-3 in combination with low amounts of CD8⁺ and CD56⁺ TILs predict extremely poor survival. The integrated analysis of TIM-3⁺, CD8⁺, and CD56⁺ TILs as one biomarker is a reliable independent predictor of prognosis. In conclusion, low densities of TIM-3⁺ TILs are associated with poor survival, and integrated immune biomarkers lead to superior predictors of GIST prognosis.

Immune Checkpoint Molecules-Inherited Variations as Markers for Cancer Risk

In recent years, immunotherapy has been revolutionized by a new approach that works by blocking receptors called immune checkpoints (IC). These molecules play a key role in maintaining immune homeostasis, mainly by suppressing the immune response and by preventing its overactivation. Since inhibition of the immune response by IC can be used by cancer to avoid recognition and destruction by immune system, blocking them enhances the anti-tumor response. This therapeutic approach has brought spectacular clinical effects. The ICs present heterogeneous expression patterns on immune cells, which may affect the effectiveness of immunotherapy. The inherited genetic variants in regulatory regions of ICs genes can be considered as potential factors responsible for observed inter-individual differences in ICs expression levels on immune cells. Additionally, polymorphism located in exons may introduce changes to ICs amino acid sequences with potential impact on functional properties of these molecules. Since genetic variants may affect both expression and structure of ICs, they are considered as risk factors of cancer development. Inherited genetic markers such as SNPs may also be useful in stratification patients into groups which will benefit from particular immunotherapy. In this review, we have comprehensively summarized the current understanding of the relationship between inherited variations of CTLA-4, PDCD1, PD-L1, BTLA, TIM-3, and LAG-3 genes in order to select SNPs which can be used as predictive biomarkers in personalized evaluation of cancer risk development and outcomes as well as possible response to immunotherapy.

LAG-3, TIM-3 and VISTA Expression on Tumor-Infiltrating Lymphocytes in Oropharyngeal Squamous Cell Carcinoma-Potential Biomarkers for Targeted Therapy Concepts

Tumor growth and survival requires a particularly effective immunosuppressant tumor microenvironment (TME) to escape destruction by the immune system. While immunosuppressive checkpoint markers like programmed cell death 1 ligand (PD-L1) are already being targeted in clinical practice, lymphocyte-activation-protein 3 (LAG-3), T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) and V-domain Ig suppressor of T cell activation (VISTA) inhibitors are currently under investigation in clinical trials. Reliable findings on the expression status of those immune checkpoint inhibitors on tumor-infiltrating lymphocytes (TILs) in the TME of oropharyngeal squamous cell carcinoma (OPSCC) are lacking. This work aims to describe the expression of LAG-3, TIM-3, and VISTA expression in the TME of OPSCC. We created a tissue microarray of paraffin-embedded tumor tissue of 241 OPSCC. Expression of the immune checkpoint protein LAG-3, TIM-3, and VISTA in OPSCC was evaluated using immunohistochemistry and results were correlated with CD8+ T-cell inflammation and human papillomavirus (HPV)-status. 73 OPSCC stained positive for LAG-3 (31%; HPV+:44%; HPV-:26%, p = 0.006), 122 OPSCC stained positive for TIM-3 (51%; HPV+:70%; HPV-:44%, p < 0.001) and 168 OPSCC (70%; HPV+:75%; HPV-:68%, p = 0.313) for VISTA. CD8+ T-cells were significantly associated with LAG-3, TIM-3 and VISTA expression (p < 0.001, p < 0.001, p = 0.007). Immune checkpoint therapy targeting LAG-3, TIM-3, and/or VISTA could be a promising treatment strategy especially in HPV-related OPSCC. Future clinical trials investigating the efficacy of a checkpoint blockade in consideration of LAG-3, TIM-3, and VISTA expression are required.

Targeting TIM-3 in solid tumors: innovations in the preclinical and translational realm and therapeutic potential

INTRODUCTION

Immune checkpoint inhibitors (ICIs) have shown a great therapeutic efficacy in cancer patients. However, a significant proportion of cancer patients remain unresponsive or show limited response. T cell immunoglobulin and mucin-domain containing protein-3 (TIM-3) is a co-inhibitory receptor expressed on various cell types and is involved in the attenuation of immune responses. TIM-3 and its ligands are highly expressed in various solid malignancies and some studies have reported its association with worse disease outcomes. Thus, targeting TIM-3 could be a promising therapeutic approach to treat cancer patients.

AREAS COVERED

This review describes the role of TIM-3 and its ligands in regulating anti-tumor immunity and their contribution to cancer progression. Moreover, this review focuses on the preclinical models and translational data from important studies published in PubMed till October 2020, which demonstrate the therapeutic benefits of targeting TIM-3 signaling.

EXPERT OPINION

Despite the promising data obtained from targeting TIM-3 in preclinical models, precise mechanisms underlying the anti-tumor effects of TIM-3 inhibition are not fully elucidated. Therefore, mechanistic studies are required to provide better insights into the anti-tumor effects of targeting TIM-3, and clinical data are necessary to determine the safety profiles and therapeutic efficacy of TIM-3 inhibition in cancer patients.

TIM-3 Expression Is Downregulated on Human NK Cells in Response to Cancer Targets in Synergy with Activation

Among natural killer (NK) cell receptors, the T-cell immunoglobulin and mucin-containing domain (TIM-3) has been associated with both inhibitory and activating functions, depending on context and activation pathway. Ex vivo and in vitro, expression of TIM-3 is inducible and depends on activation stimulus. Here, we report that TIM-3 expression can be downregulated on NK cells under specific conditions. When NK cells are exposed to cancer targets, they synergize with stimulation conditions to induce a substantial decrease in TIM-3 expression on their surface. We found that such downregulation occurs following prior NK activation. Downregulated TIM-3 expression correlated to lower cytotoxicity and lower interferon gamma (IFN-γ) expression, fueling the notion that TIM-3 might function as a benchmark for human NK cell dysfunction.

Identification of a four immune-related genes signature based on an immunogenomic landscape analysis of clear cell renal cell carcinoma

Renal clear cell carcinoma (ccRCC) is the most common type of renal cell carcinoma, which has strong immunogenicity. A comprehensive study of the role of immune-related genes (IRGs) in ccRCC is of great significance in finding ccRCC treatment targets and improving patient prognosis. In this study, we comprehensively analyzed the expression of IRGs in ccRCC based on The Cancer Genome Atlas datasets. The mechanism of differentially expressed IRGs in ccRCC was analyzed by bioinformatics. In addition, Cox regression analysis was used to screen prognostic related IRGs from differentially expressed IRGs. We also identified a four IRGs signature consisting of four IRGs (CXCL2, SEMA3G, PDGFD, and UCN) through lasso regression and multivariate Cox regression analysis. Further analysis results showed that the four IRGs signature could effectively predict the prognosis of patients with ccRCC, and its predictive power is independent of other clinical factors. In addition, the correlation analysis of immune cell infiltration showed that this four IRGs signature could effectively reflect the level of immune cell infiltration of ccRCC. We also found that the expression of immune checkpoint genes CTLA-4, LAG3, and PD-1 in the high-risk group was higher than that in the low-risk group. Our research revealed the role of IRGs in ccRCC, and developed a four IRGs signature that could be used to evaluate the prognosis of patients with ccRCC, which will help to develop personalized treatment strategies for patients with ccRCC and improve their prognosis. In addition, these four IRGs may be effective therapeutic targets for ccRCC.

Tumour grade significantly correlates with total dysfunction of tumour tissue-infiltrating lymphocytes in renal cell carcinoma

It is important to evaluate the clinical importance of both CD8 T cells and CD4 T cells expression simultaneously because they have crucial networks in tumour targeting immune responses. In 97 RCC patients, RNA sequencing and gene set enrichment analysis of both CD8 and CD4 T cells based on the expression levels of PD-1 and TIM-3 implied that the populations of PD-1+TIM-3+ CD8 T cells and PD-1lowTIM-3 + CD4 T cells were characterized as exhausted CD8 T cells and regulatory CD4 T cells, respectively. These populations of CD4 and CD8 T cells were significantly upregulated in the patients with RCC of higher WHO/ISUP grade (grades 3, 4) (P < 0.001). Moreover, the cytokine productivities of each population in both CD4 and CD8 T cells of the higher-grade patients were significantly lower than those of the lower-grade patients (P < 0.05). Multivariate analysis showed the prognosis of patients with metastatic RCC of higher WHO/ISUP grade treated by nivolumab to be significantly worse than that of patients with lower grade (P = 0.026). This study showed that tumour grade significantly correlated with dysfunction of both CD4+ and CD8+ TILs and the efficacy of nivolumab treatment.

Reverting Immune Suppression to Enhance Cancer Immunotherapy

Tumors employ strategies to escape immune control. The principle aim of most cancer immunotherapies is to restore effective immune surveillance. Among the different processes regulating immune escape, tumor microenvironment-associated soluble factors, and/or cell surface-bound molecules are mostly responsible for dysfunctional activity of tumor-specific CD8⁺T cells. These dynamic immunosuppressive networks prevent tumor rejection at several levels, limiting also the success of immunotherapies. Nevertheless, the recent clinical development of immune checkpoint inhibitors or of molecules modulating cellular targets and immunosuppressive enzymes highlights the great potential of approaches based on the selective disruption of immunosuppressive networks. Currently, the administration of different categories of immunotherapy in combination regimens is the ultimate modality for impacting the survival of cancer patients. With the advent of immune checkpoint inhibitors, designed to mount an effective antitumor immune response, profound changes occurred in cancer immunotherapy: from a global stimulation of the immune system to a specific targeting of an immune component. This review will specifically highlight the players, the mechanisms limiting an efficient antitumor response and the current immunotherapy modalities tailored to target immune suppressive pathways. We also discuss the ongoing challenges encountered by these strategies and provide suggestions for circumventing hurdles to new immunotherapeutic approaches, including the use of relevant biomarkers in the optimization of immunotherapy regimens and the identification of patients who can benefit from defined immune-based approaches.

Tumor microenvironmental influences on dendritic cell and T cell function: A focus on clinically relevant immunologic and metabolic checkpoints

Cancer immunotherapy is fast becoming one of the most promising means of treating malignant disease. Cancer vaccines, adoptive cell transfer therapies, and immune checkpoint blockade have all shown varying levels of success in the clinical management of several cancer types in recent years. However, despite the clinical benefits often achieved by these regimens, an ongoing problem for many patients is the inherent or acquired resistance of their cancer to immunotherapy. It is now appreciated that dendritic cells and T lymphocytes both play key roles in antitumor immune responses and that the tumor microenvironment presents a number of barriers to the function of these cells that can ultimately limit the success of immunotherapy. In particular, the engagement of several immunologic and metabolic checkpoints within the hostile tumor microenvironment can severely compromise the antitumor functions of these important immune populations. This review highlights work from both preclinical and clinical studies that has shaped our understanding of the tumor microenvironment and its influence on dendritic cell and T cell function. It focuses on clinically relevant targeted and immunotherapeutic strategies that have emerged from these studies in an effort to prevent or overcome immune subversion within the tumor microenvironment. Emphasis is also placed on the potential of next-generation combinatorial regimens that target metabolic and immunologic impediments to dendritic cell and T lymphocyte function as strategies to improve antitumor immune reactivity and the clinical outcome of cancer immunotherapy going forward.

Association between TIM-3 polymorphisms and cancer risk: a meta-analysis

BACKGROUND

Single nucleotide polymorphisms (SNPs) of T-cell immunoglobulin- and mucin-domain-containing molecule 3 (TIM-3) were reported to individually associate with cancer risk. To further verify its correlation with human cancers, we evaluated the association of TIM-3 polymorphisms and the risk of cancer.

METHODS

Data were collected from electronic databases. Two reviewers independently selected studies, extracted data and assessed quality of the studies. Data were meta-analyzed using the STATA 13.0 software. Crude odd ratio (OR) and 95% confidence interval was used to estimate the association between TIM-3 polymorphism and cancer susceptibility.

RESULTS

All eligible case-control studies included a total of 4,852 participants (2,229 cases and 2,623 controls). The meta-analysis showed that TIM-3 SNPs (-1516G/T, -574G/T, +4259T/G, and haplotypes) were significantly associated with an increased risk of susceptibility toward all cancers. The subgroup analyses based on cancer types showed that TIM-3 -1516G/T SNP was only associated with an increased risk in developing cancers in the digestive system or in hospital-based populations. Moreover, the TIM-3 -574G/T SNP was associated with an increased cancer risk in the digestive system or other systems, while TIM-3 +4259T/G SNP was only associated with an increased cancer risk in hospital-based populations. Among the four haplotypes observed (GGT, TGT, GGG, and GTT), The GGG haplotype showed an increase in the odds of cancer by 2.614-fold (OR 2.614; 95% CI: 1.756-3.893) compared with the GGT haplotype.

CONCLUSIONS

TIM-3 SNPs (-1516G/T, -574G/T, +4259T/G and the four haplotypes) were associated with an increased risk of developing human cancers.

Does selected immunological panel possess the value of predicting the prognosis of early-stage resectable non-small cell lung cancer?

Background

The immune status in the tumor micro-environment of lung cancer is highly informative, and expression status of some biomarkers in the tumor micro-environment may have deep connected statistical characteristics which could indicate immune status and predict related clinical outcomes. In this study, a panel of 9 immune biomarkers are selected for their possible predictive value of clinical outcomes in early-stage resectable non-small cell lung cancer (NSCLC).

Methods

We introduced a new way of interpreting the expression of Immunohistochemistry-based biomarkers in predicting the prognosis of patients. Immunohistochemistry were performed on surgical samples from 139 patients with NSCLC. Cox regression and subgroup analysis were conducted for the screening of biomarkers that were significant in survival and prognosis. Afterwards, Principle Component Analysis was conducted on screened biomarkers in order to extract characteristic root, which were utilized by an Artificial Neuron Network (ANN) for the prediction of clinical outcomes.

Results

Six out of 9 biomarkers were considered significant and were selected for the data analysis. The KMO-Bartlett's Sphericity test was valid (0.658>0.5, P=0.0001). The principle component regression results indicated that the survival was associated with the principle component Z4 (Y=0.316×Z4+2.298, R=0.189, P=0.026). Also, regression-free survival was associated with the principle component Z4 and Z2 (Y=0.314×Z4+0.255×Z2+2.061, R=0.249, P=0.013). Principle components ranking (PCrank) was calculated and after the determination of a cutoff of 0.2, the intergroup comparison of subgrouphigh (PCrank value above 0.2) and subgrouplow (PCrank value below 0.2) was significant in overall survival (OS) (P=0.025). A database search validated our results. Afterwards, the ANN model successfully predicted the clinical outcome, with accuracies of 94.1% and 96.2% respectively in models 1 and 2.

Conclusions

The selected immunological panels have promising potential for predicting the prognosis of resectable NSCLC.

On the Horizon: Targeting Next-Generation Immune Checkpoints for Cancer Treatment

BACKGROUND

Immune checkpoints are critical regulatory pathways of the immune system which finely tune the response to biological threats. Among them, the CD-28/CTLA-4 and PD-1/PD-L1 axes play a key role in tumour immune escape and are well-established targets of cancer immunotherapy.

SUMMARY

The clinical experience accumulated to date provides unequivocal evidence that anti-CTLA-4, PD-1, or PD-L1 monoclonal antibodies, used as monotherapy or in combination regimes, are effective in a variety of advanced/metastatic types of cancer, with improved clinical outcomes compared to conventional chemotherapy. However, the therapeutic success is currently restricted to a limited subset of patients and reliable predictive biomarkers are still lacking. Key Message: The identification and characterization of additional co-inhibitory pathways as novel pharmacological targets to improve the clinical response in refractory patients has led to the development of different immune checkpoint inhibitors, the activities of which are currently under investigation. In this review, we discuss recent literature data concerning the mechanisms of action of next-generation monoclonal antibodies targeting LAG-3, TIM-3, and TIGIT co-inhibitory molecules that are being explored in clinical trials, as single agents or in combination with other immune-stimulating agents.

Immune phenotype of peripheral blood mononuclear cells in patients with high-risk non-muscle invasive bladder cancer

PURPOSE

To explore the immune phenotype of peripheral blood mononuclear cells (PBMC) in patients with high-risk non-muscle invasive bladder cancer (NMIBC).

METHODS

We prospectively collected blood samples from patients with high-risk NMIBC treated at our institution. PBMC were analyzed by flow cytometry to determine the frequency of T cells and NK cells and the expression of immunoregulatory molecules (Tim-3, TIGIT and PD-1). PBMC from healthy donors (HD) were included for comparison, and associations with response to BCG were investigated.

RESULTS

A total of 38 patients were included, 19 BCG responders and 19 BCG refractory. Compared to 16 PBMC from HD, the frequency of total NK cells was significantly higher in patients with NMIBC [15.2% (IQR: 11.4, 22.2) vs. 5.72% (IQR: 4.84, 9.79); p = 0.05], whereas the frequency of T cells was not statistically different. Both Tim-3 and TIGIT expressions were significantly higher in NMIBC compared to HD, particularly in NK cells [13.8% (11.0; 22.4) vs. 5.56% (4.20; 10.2) and 34.9% (18.9; 53.5) vs. 1.82% (0.63; 5.16), respectively; p < 0.001]. Overall, the expression of PD-1 in all cell types was low in both NMIBC patients and HD. The immune phenotype was not significantly different before and after initiation of BCG. However, the proportion of CD8+ T cells before BCG was significantly higher in responders.

CONCLUSION

The immune phenotype of PBMC from patients with high-risk NMIBC was significantly different from HD, regardless of the presence of disease or the initiation of BCG. Peripheral CD8+ T cells could play a role in response to BCG.

TIM-3, a promising target for cancer immunotherapy

Patients with malignant tumor treated with immunotherapy have received significant clinical benefits over the years. Immune checkpoint blocking agents, such as anti-cytotoxic T-lymphocyte-associated protein-4 (anti-CTLA-4) and anti-programmed cell death protein-1 (anti-PD-1) monoclonal antibodies, have produced impressive clinical results in different types of cancer. T-cell immunoglobulin and mucin domain-3 (TIM-3), another immune checkpoint, could inhibit cancer immunity. Recent studies have highlighted that TIM-3 has an important role to play in T-cell exhaustion and correlates with the outcome of anti-PD-1 therapy. Targeting TIM-3 might be a promising approach for cancer immunotherapy. Here, we review the role of TIM-3 in cancer and clinical trials with TIM-3 inhibitors.

Downregulated Tim-3 expression is responsible for the incidence and development of colorectal cancer

The present study aimed to investigate the role of T cell immunoglobulin domain and mucin-3 (Tim-3) in its gene and protein forms in colorectal cancer (CRC), and to verify the significance of Tim-3 expression in patients with CRC. A prospective analysis of 258 patients with CRC and 246 normal controls was conducted between December 2012 and June 2015. Intestinal samples were collected, including of CRC tissues, paracancerous tissues and normal colon mucosa tissues. Peripheral venous blood samples were also collected. Polymerase chain reaction (PCR) amplification, reverse transcription-quantitative PCR (RT-qPCR) and western blot analysis was performed for the detection and evaluation of Tim-3 gene and protein in various tissues. PCR analysis indicated that the T and G alleles of -882C/T and 4259T/G are associated with a significantly increased risk of CRC. Following the confirmation of Tim-3 expression in CRC tissues, RT-qPCR detection and western blot analysis revealed clear downregulation of Tim-3 mRNA and protein expression in the blood and tissue samples obtained from patients with CRC, as compared with in the corresponding control samples. Similar trends of decreased Tim-3 mRNA levels and protein expression were observed in CRC tissues compared with in the paracancerous and the normal colon mucosa tissues. In addition, the mRNA and protein expression levels in the paracancerous tissues were lower than those in the normal colon mucosa tissues. Furthermore, significantly lower Tim-3 mRNA levels were observed in patients with a tumor size >5 cm, a poor differentiation degree, higher tumor-node-metastasis stage (stage III-IV), and lymph node and distant metastasis. Collectively, genetic changes to Tim-3, expressed as polymorphisms in Tim-3, and decreased mRNA/protein expression may be partially responsible for the incidence and development of CRC.

Multiplexed Immunofluorescence Analysis and Quantification of Intratumoral PD-1+ Tim-3+ CD8+ T Cells

Immune cells are important components of the tumor microenvironment and influence tumor growth and evolution at all stages of carcinogenesis. Notably, it is now well established that the immune infiltrate in human tumors can correlate with prognosis and response to therapy. The analysis of the immune infiltrate in the tumor microenvironment has become a major challenge for the classification of patients and the response to treatment. The co-expression of inhibitory receptors such as Program Cell Death Protein 1 (PD1; also known as CD279), Cytotoxic T Lymphocyte Associated Protein 4 (CTLA-4), T-Cell Immunoglobulin and Mucin Containing Protein-3 (Tim-3; also known as CD366), and Lymphocyte Activation Gene 3 (Lag-3; also known as CD223), is a hallmark of T cell exhaustion. We developed a multiparametric in situ immunofluorescence staining to identify and quantify at the cellular level the co-expression of these inhibitory receptors. On a retrospective series of frozen tissue of renal cell carcinomas (RCC), using a fluorescence multispectral imaging technology coupled with an image analysis software, it was found that co-expression of PD-1 and Tim-3 on tumor infiltrating CD8⁺ T cells is correlated with a poor prognosis in RCC. To our knowledge, this represents the first study demonstrating that this automated multiplex in situ technology may have some clinical relevance.

Low TIM3 expression indicates poor prognosis of metastatic prostate cancer and acts as an independent predictor of castration resistant status

T cell immunoglobulin 3 (TIM3) is a cell surface star molecule expressed on T cells, and also marks dysfunctional CD8⁺ T cells in various kinds of cancers. However, there are few studies focusing on the expression of TIM3 in tumor cells. In our study, we recruited 139 patients with metastatic prostate cancer (mPCa) who received transurethral resection of the prostate (TURP) consecutively to examine whether TIM3 expression level is associated with overall survival (OS) in mPCa patients. Immunohistochemistry was performed to determine TIM3 expression in prostate cancer tissues and then patients were divided into two groups. In multivariate Cox analysis, we revealed that mPCa patients with negative TIM3 expression, younger age, no radiotherapy, higher Gleason score, higher cT stage and patients of mCRPC had a shorter OS. Therefore, a predictive nomogram was generated with identified independent prognostic factors to assess patients’ OS at 3 years. Multivariate logistic regression revealed that higher cT stage, higher Gleason score and low TIM3 expression were independent predictors of metastatic castration resistant prostate cancer (mCRPC). In conclusion, low expression level of TIM3 in prostate cancer tissues is an independent prognostic factor of poor prognosis for mPCa patients, and also an independent predictor of mCRPC.

Molecular and clinical characterization of TIM-3 in glioma through 1,024 samples

Background: Researches on immunotherapy of glioma has been increasing exponentially in recent years. However, autoimmune-like side effects of current immune checkpoint blockade hindered the clinical application of immunotherapy in glioma. The discovery of the TIM-3, a tumor-specific immune checkpoint, has shed a new light on solution of this dilemma. We aimed at investigating the role of TIM-3 at transcriptome level and its relationship with clinical practice in glioma. Methods: A cohort of 325 glioma patients with RNA-seq data from Chinese Glioma Genome Atlas (CGGA project) was analyzed, and the results were well validated in TCGA RNA-seq data of 699 gliomas. R language was used as the main tool for statistical analysis and graphical work. Results: TIM-3 was enriched in glioblastoma (the most malignant glioma) and IDH-wildtype glioma. TIM-3 can act as a potential marker for mesenchymal molecular subtype according to TCGA transcriptional classification scheme in glioma. TIM-3 was closely related to immune functions in glioma, especially T cell mediated immune response to tumor cell and T cell mediated cytotoxicity directed against tumor cell target. Moreover, TIM-3 and PD-L1 played almost exactly the same inflammatory activation functions in glioma. Clinically, high expression of TIM-3 was an independent indicator of poor prognosis. Conclusion: The expression of TIM-3 is closely related to the pathology and molecular pathology of glioma. Meanwhile, in glioma TIM-3 plays a specific role in T cell tumor immune response. Therefore, TIM-3 is a promising target for immunotherapeutic strategies, providing an alternative treatment when glioma gains resistance to antibodies of PD-1/PD-L1.

Combined Blockade of T Cell Immunoglobulin and Mucin Domain 3 and Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 Results in Durable Therapeutic Efficacy in Mice with Intracranial Gliomas

Background

Glioblastoma multiforme (GBM) evades immune surveillance by inducing immunosuppression via receptor-ligand interactions between immune checkpoint molecules. T cell immunoglobulin and mucin domain 3 (Tim-3) is a key checkpoint receptor responsible for exhaustion and dysfunction of T cells and plays a critical role in immunosuppression. Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) has been recently identified as a heterophilic ligand for Tim-3.

Material/Methods

We established an intracranial GBM model using C57BL/6 mice and GL261 cells, and treated the mice with single or combined monoclonal antibodies (mAbs) against Tim-3/CEACAM1. The CD4⁺, CD8⁺, and regulatory T cells in brain-infiltrating lymphocytes were analyzed using flow cytometry, and the effector function of T cells was assessed using ELISA. We performed a rechallenge by subcutaneous injection of GL261 cells in the “cured” (>90 days post-orthotopic tumor implantation) and naïve mice.

Results

The mean survival time in the control, anti-Tim-3, anti-CEACAM1, and combined treatment groups was 29.8, 43.4, 42.3, and 86.0 days, respectively, with 80% of the mice in the combined group becoming long-term survivors showing immune memory against glioma cells. Infiltrating CD4⁺ and CD8⁺ T cells increased and immunosuppressive Tregs decreased with the combined therapy, which resulted in a markedly elevated ratio of CD4⁺ and CD8⁺ cells to Tregs. Additionally, plasma IFN-γ and TGF-β levels were upregulated and downregulated, respectively.

Conclusions

Our data indicate that combined blockade of Tim-3 and CEACAM1 generates robust therapeutic efficacy in mice with intracranial tumors, and provides a promising option for GBM immunotherapy.

Preoperative Tim‑3 expression on peripheral NK cells is correlated with pathologic TNM staging in colorectal cancer

Previous research has indicated that T cell immunoglobulin and mucin domain 3 (Tim-3) serves an important regulatory role in lymphocytes and in several cancers. However, the association between Tim‑3 expression on various lymphocyte subsets and human colorectal cancer (CRC) has not been elucidated. The present study aimed to characterize Tim‑3 expression on peripheral lymphocytes, including cluster of differentiation CD3+CD56‑ T cells, CD3‑CD56+ natural killer (NK) cells and CD3+CD56+ natural killer T (NKT) cells, in patients with CRC. The frequency of T cells, NK cells and NKT cells expressing Tim‑3 was assessed by multicolor flow cytometry of peripheral blood collected from 36 preoperative CRC patients and 38 healthy donors. The expression of Tim‑3 on lymphocyte subsets from 53 postoperative blood samples of CRC patients was also analyzed. There were fewer circulating NK cells in patients with CRC compared with healthy controls (P=0.0027); NK cell expression of Tim‑3 was also significantly decreased (P=0.0239). The frequency of circulating NK cells and Tim‑3+ NK cells was negatively correlated with clinical cancer stage, compared with healthy controls, but not with other clinicopathological parameters or serum concentrations of CRC biomarkers. Furthermore, the expression of Tim‑3 in NK cells was higher in CRC patients without metastasis. Notably, NK cell Tim‑3 expression in CRC patients was significantly restored following surgical resection of the primary tumor. In conclusion, the present study indicates the presence of an altered frequency and expression of Tim‑3 in peripheral NK cells in CRC patients. Preoperative Tim‑3 expression on peripheral NK cells is correlated with differential staging in colorectal cancer, and may be useful as a serum biomarker.

TIM-3 as a Target for Cancer Immunotherapy and Mechanisms of Action

Cancer immunotherapy has produced impressive clinical results in recent years. Despite the success of the checkpoint blockade strategies targeting cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed death receptor 1 (PD-1), a large portion of cancer patients have not yet benefited from this novel therapy. T cell immunoglobulin and mucin domain 3 (TIM-3) has been shown to mediate immune tolerance in mouse models of infectious diseases, alloimmunity, autoimmunity, and tumor Immunity. Thus, targeting TIM-3 emerges as a promising approach for further improvement of current immunotherapy. Despite a large amount of experimental data showing an immune suppressive function of TIM-3 in vivo, the exact mechanisms are not well understood. To enable effective targeting of TIM-3 for tumor immunotherapy, further in-depth mechanistic studies are warranted. These studies will also provide much-needed insight for the rational design of novel combination therapy with other checkpoint blockers. In this review, we summarize key evidence supporting an immune regulatory role of TIM-3 and discuss possible mechanisms of action.

Tim-3 Expression on Tumor-Infiltrating PD-1+CD8+ T Cells Correlates with Poor Clinical Outcome in Renal Cell Carcinoma

Inhibitory receptors expressed by T cells mediate tolerance to tumor antigens, with coexpression of these receptors exacerbating this dysfunctional state. Using the VectraR automated multiparametric immunofluorescence technique, we quantified intratumoral CD8⁺ T cells coexpressing the inhibitory receptors PD-1 and Tim-3 from patients with renal cell carcinoma (RCC). A second validation cohort measured the same parameters by cytometry. The percentage of tumor-infiltrating CD8⁺ T cells coexpressing PD-1 and Tim-3 correlated with an aggressive phenotype and a larger tumor size at diagnosis. Coexpression of PD-1 and Tim-3 above the median conferred a higher risk of relapse and a poorer 36-month overall survival. Notably, other CD8⁺T-cell subsets did not exert a similar effect on overall survival. Moreover, only the PD-1⁺Tim-3⁺ subset of CD8⁺ T cells exhibited impaired function after stimulation. Our findings establish intratumoral Tim-3⁺PD1⁺CD8⁺ T cells as critical mediators of an aggressive phenotype in RCC. Use of the Vectra tool may be useful to identify similarly critical prognostic and predictive biomarkers in other tumor types and their response to immunotherapy. Cancer Res; 77(5); 1075-82. ©2016 AACR.

Immune Regulation and Antitumor Effect of TIM-1

T cells play an important role in antitumor immunity, and the T cell immunoglobulin domain and the mucin domain protein-1 (TIM-1) on its surface, as a costimulatory molecule, has a strong regulatory effect on T cells. TIM-1 can regulate and enhance type 1 immune response of tumor association. Therefore, TIM-1 costimulatory pathways may be a promising therapeutic target in future tumor immunotherapy. This review describes the immune regulation and antitumor effect of TIM-1.