Emerging targets in cancer immunotherapy

The emergence of tumor-infiltrating lymphocytes in nasopharyngeal carcinoma: Predictive value and immunotherapy implications

The clinical study of nasopharyngeal carcinoma (NPC) often reveals a large number of lymphocytes infiltrating the primary tumor site. As an important part of the tumor microenvironment, tumor-infiltrating lymphocytes (TILs) do not exist alone but as a complex multicellular population with high heterogeneity. TILs play an extremely significant role in the occurrence, development, invasion and metastasis of NPC. The latest research shows that they participate in tumorigenesis and treatment, and the composition, quantity, functional status and distribution of TILs subsets have good predictive value for the prognosis of NPC patients. TILs are an independent prognostic factor for TNM stage and significantly correlated with better prognosis. Additionally, adoptive immunotherapy using anti-tumor TILs has achieved good results in a variety of solid tumors including NPC. This review evaluates recent clinical and preclinical studies of NPC, summarizes the role of TILs in promoting and inhibiting tumor growth, evaluates the predictive value of TILs, and explores the potential benefits of TILs-based immunotherapy in the treatment of NPC.

Phytochemicals in Cancer Immune Checkpoint Inhibitor Therapy

The interaction of immune checkpoint molecules in the tumor microenvironment reduces the anti-tumor immune response by suppressing the recognition of T cells to tumor cells. Immune checkpoint inhibitor (ICI) therapy is emerging as a promising therapeutic option for cancer treatment. However, modulating the immune system with ICIs still faces obstacles with severe immunogenic side effects and a lack of response against many cancer types. Plant-derived natural compounds offer regulation on various signaling cascades and have been applied for the treatment of multiple diseases, including cancer. Accumulated evidence provides the possibility of efficacy of phytochemicals in combinational with other therapeutic agents of ICIs, effectively modulating immune checkpoint-related signaling molecules. Recently, several phytochemicals have been reported to show the modulatory effects of immune checkpoints in various cancers in in vivo or in vitro models. This review summarizes druggable immune checkpoints and their regulatory factors. In addition, phytochemicals that are capable of suppressing PD-1/PD-L1 binding, the best-studied target of ICI therapy, were comprehensively summarized and classified according to chemical structure subgroups. It may help extend further research on phytochemicals as candidates of combinational adjuvants. Future clinical trials may validate the synergetic effects of preclinically investigated phytochemicals with ICI therapy.

Immunotherapy-Based Therapeutic Strategies for Recurrent Advanced Squamous Cell Carcinoma of the Head and Neck: A Case Report and Literature Review

We present a patient with locoregionally advanced laryngeal carcinoma, who experienced recurrence 2 months after surgery. We exploratively treated this patient with immunotherapy combined with targeted therapy with or without radiation therapy. The patient exhibited a significant and durable response. Thus far, there are no standard or effective second-line therapeutic modalities for recurrent locoregionally advanced laryngeal carcinoma. The efficacy of conventional chemotherapy with anti-epidermal growth factor receptor (anti-EGFR) remains unsatisfactory. The addition of immunotherapy resulted in substantial improvement in the progression-free survival (PFS) and overall survival (OS) of this patient. In this case, immunotherapy combined with anti-EFGR was administered, leading to good tumor response; based on this observation, radiotherapy was added to further intensify tumor control. This therapeutic strategy may be a novel option for recurrent locoregionally advanced squamous cell carcinoma of the head and neck.

Correlations between tumor mutation burden and immune infiltrates and their prognostic value in pancreatic cancer by bioinformatic analysis

PURPOSE

We aimed to investigate the patterns and prognostic roles of tumor mutation burden and immune microenvironment in pancreatic cancer.

METHODS

The somatic mutation data, transcriptome profiles and clinical information were downloaded from the Cancer Genome Atlas database. Gene expression difference, Gene ontology, KEGG, gene set enrichment analyses and "CIBERSORT" algorithm were performed to screen differentially expressed genes, enriched functions or pathways and immune infiltrates differences between high and low TMB groups. Single sample gene set enrichment and unsupervised consensus clustering analyses were used for immunity grouping. Immune cell infiltration and expressions of HLA and checkpoint genes were investigated. Finally, a nomogram model integrating TMB and immune infiltration was established.

RESULTS

A total of 608 differentially expressed genes were identified between high and low TMB groups, KEGG base excision repair and DNA replication pathways were enriched in high TMB group. Infiltration levels of M0 macrophages were higher and dendritic resting cells were lower in high TMB group. The risk model based on TMB-related immune genes, FAM19A2 and SLC22A17 was established and high risk scores indicated poorer prognosis. The expressions of HLA genes and immune checkpoint genes were higher in high immunity group. The nomogram showed remarkable ability for individualized survival estimation with good AUC values (0.794 and 0.800, respectively) for 3- and 5-year survival rates prediction.

CONCLUSIONS

The characteristics of tumor mutation burden and immune infiltration in pancreatic cancer provide new insights into the tumor microenvironment, immunotherapies and a novel prognostic nomogram model for pancreatic cancer patients.

Angiogenic Properties of NK Cells in Cancer and Other Angiogenesis-Dependent Diseases

The pathogenesis of many serious diseases, including cancer, is closely related to disturbances in the angiogenesis process. Angiogenesis is essential for the progression of tumor growth and metastasis. The tumor microenvironment (TME) has immunosuppressive properties, which contribute to tumor expansion and angiogenesis. Similarly, the uterine microenvironment (UME) exerts a tolerogenic (immunosuppressive) and proangiogenic effect on its cells, promoting implantation and development of the embryo and placenta. In the TME and UME natural killer (NK) cells, which otherwise are capable of killing target cells autonomously, enter a state of reduced cytotoxicity or anergy. Both TME and UME are rich with factors (e.g., TGF-β, glycodelin, hypoxia), which support a conversion of NK cells to the low/non-cytotoxic, proangiogenic CD56^brightCD16^low phenotype. It is plausible that the phenomenon of acquiring proangiogenic and low cytotoxic features by NK cells is not only limited to cancer but is a common feature of different angiogenesis-dependent diseases (ADDs). In this review, we will discuss the role of NK cells in angiogenesis disturbances associated with cancer and other selected ADDs. Expanding the knowledge of the mechanisms responsible for angiogenesis and its disorders contributes to a better understanding of ADDs and may have therapeutic implications.

Prognostic significance of CD163+ tumor-associated macrophages in colorectal cancer

Background

This study aimed to explore the prognostic significance of tumor-associated macrophage (TAM) infiltration in colorectal cancer (CRC) patients.

Methods

Tissue microarray and immunohistochemistry were used to detect the infiltration of CD163+ TAMs in 209 CRC samples, and the Kaplan–Meier method was used for survival analysis. Cox proportional hazards analysis was used for univariate analysis and multivariate analysis of clinically relevant confounders.

Results

The samples were divided into low-level (n = 105) and high-level infiltration groups (n = 104) by the median number of CD163+ TAMs detected. The overall survival (OS) and disease-free survival (DFS) of CRC patients in the low-level CD163+ TAM infiltration group were longer than those in the high-level CD163+ TAM infiltration group (P < 0.001). Infiltration of CD163+ TAMs in CRC tissues was a negative prognostic factor for CRC patients. Risks of death and disease recurrence for CRC patients in the low-level CD163+ TAM infiltration group were lower than those in the high-level CD163+ TAM infiltration group (HR_OS = 0.183, 95% CI 0.052–0.647, P = 0.008; HR_DFS = 0.191, 95% CI 0.078–0.470, P = 0.000).

Conclusions

The infiltration of CD163+ TAMs in CRC tissue is an independent adverse factor for the prognosis of CRC patients. High-level infiltration of CD163+ TAMs is associated with shorter OS and DFS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02299-y.

CARTmath-A Mathematical Model of CAR-T Immunotherapy in Preclinical Studies of Hematological Cancers

Immunotherapy has gained great momentum with chimeric antigen receptor T cell (CAR-T) therapy, in which patient's T lymphocytes are genetically manipulated to recognize tumor-specific antigens, increasing tumor elimination efficiency. In recent years, CAR-T cell immunotherapy for hematological malignancies achieved a great response rate in patients and is a very promising therapy for several other malignancies. Each new CAR design requires a preclinical proof-of-concept experiment using immunodeficient mouse models. The absence of a functional immune system in these mice makes them simple and suitable for use as mathematical models. In this work, we develop a three-population mathematical model to describe tumor response to CAR-T cell immunotherapy in immunodeficient mouse models, encompassing interactions between a non-solid tumor and CAR-T cells (effector and long-term memory). We account for several phenomena, such as tumor-induced immunosuppression, memory pool formation, and conversion of memory into effector CAR-T cells in the presence of new tumor cells. Individual donor and tumor specificities are considered uncertainties in the model parameters. Our model is able to reproduce several CAR-T cell immunotherapy scenarios, with different CAR receptors and tumor targets reported in the literature. We found that therapy effectiveness mostly depends on specific parameters such as the differentiation of effector to memory CAR-T cells, CAR-T cytotoxic capacity, tumor growth rate, and tumor-induced immunosuppression. In summary, our model can contribute to reducing and optimizing the number of in vivo experiments with in silico tests to select specific scenarios that could be tested in experimental research. Such an in silico laboratory is an easy-to-run open-source simulator, built on a Shiny R-based platform called CARTmath. It contains the results of this manuscript as examples and documentation. The developed model together with the CARTmath platform have potential use in assessing different CAR-T cell immunotherapy protocols and its associated efficacy, becoming an accessory for in silico trials.

Prognostic and Clinicopathologic Associations of LAG-3 Expression in Triple-negative Breast Cancer

The immune checkpoint molecule lymphocyte activation gene 3 (LAG-3) is currently being investigated as a possible target for immunotherapy in triple-negative breast cancer (TNBC), frequently as an addition to treatment with programmed cell death protein 1/programmed death ligand 1 (PD-L1) inhibition. However, expression of LAG-3, the frequency of coexpression with PD-L1, and the prognostic significance of this marker have not been studied extensively in TNBC. For this study, tissue microarrays (TMAs) were constructed from surgical specimens of 514 patients with TNBC. TMAs were stained immunohistochemically for LAG-3 and PD-L1 expression. Tumor-infiltrating lymphocytes (TILs) were evaluated on full glass slides. LAG-3 expression was significantly associated with improved overall survival and relapse-free survival. When adjusted for clinicopathologic factors, each increment of 10 LAG-3-positive intratumoral lymphocytes per TMA core was associated with improved overall survival (hazard ratio=0.93, 95% confidence interval: 0.89-0.97, P=0.002), and recurrence-free survival (hazard ratio=0.91, 95% confidence interval: 0.85-0.97, P=0.002). PD-L1 expression on immune cells and PD-L1 expression evaluated with the combined positive score and TILs were also associated with improved survival in both univariate and multivariate analyses. PD-L1 expression on tumor cells was only associated with improved survival in univariate analysis. LAG-3 expression was associated with both TILs and PD-L1 expression. Coexpression of LAG-3 and PD-L1 did not confer additional survival benefits. In conclusion, LAG-3 expression is associated with improved survival in TNBC. LAG-3 is often coexpressed with PD-L1, confirming that TNBC is likely a suitable candidate for cotreatment with LAG-3 and programmed cell death protein 1/PD-L1 inhibitors. However, coexpression does not confer additional survival benefits.

TriMix and tumor antigen mRNA electroporated dendritic cell vaccination plus ipilimumab: link between T-cell activation and clinical responses in advanced melanoma

Background

We previously reported that dendritic cell-based mRNA vaccination plus ipilimumab (TriMixDC-MEL IPI) results in an encouraging rate of tumor responses in patients with pretreated advanced melanoma. Here, we report the TriMixDC-MEL IPI-induced T-cell responses detected in the peripheral blood.

Methods

Monocyte-derived dendritic cells electroporated with mRNA encoding CD70, CD40 ligand, and constitutively active TLR4 (TriMix) as well as the tumor-associated antigens tyrosinase, gp100, MAGE-A3, or MAGE-C2 were administered together with IPI for four cycles. For 18/39 patients, an additional vaccine was administered before the first IPI administration. We evaluated tumor-associated antigen specific T-cell responses in previously collected peripheral blood mononuclear cells, available from 15 patients.

Results

Vaccine-induced enzyme-linked immunospot assay responses detected after in vitro T-cell stimulation were shown in 12/15 patients. Immune responses detected in patients with a complete or partial response were significantly stronger and broader, and exhibited a higher degree of multifunctionality compared with responses in patients with stable or progressive disease. CD8+ T-cell responses from patients with an ongoing clinical response, either elicited by TriMixDC-MEL IPI or on subsequent pembrolizumab treatment, exhibited the highest degree of multifunctionality.

Conclusions

TriMixDC-MEL IPI treatment results in robust CD8+ T-cell responses in a meaningful portion of stage III or IV melanoma patients, and obviously in patients with a clinical response. The levels of polyfunctional and multiantigen T-cell responses measured in patients with a complete response, particularly in patients evidently cured after 5+ years of follow-up, may provide a benchmark for the level of immune stimulation needed to achieve a durable clinical remission.

Trial registration number

NCT01302496.

CD94 expression patterns in reactive and neoplastic T-cell and NK-cell proliferations

Lymphomas and leukemias of T-cell and NK-cell lineages are highly heterogeneous disorders and lack effective therapeutic strategies. Targeted therapies including anti-CD94 agents are currently under clinical investigation, but studies of CD94 expression on mature T/NK-cell neoplasms are limited. In this study, we investigated the landscape of CD94 protein expression in 15 patients with reactive T/NK-cell proliferations and 124 patients with various T/NK cell neoplasms. CD94 expression was detected at a high level in reactive NK-cells, with a lower level of expression in a subset of reactive CD8 + T-cells; reactive CD4 + T-cells were negative for CD94 expression. All NK-cell neoplasms surveyed had high-level CD94 expression, which was significantly higher than that in T cell neoplasms (p = 0.0174). In neoplastic T-cell proliferations, CD94 expression was positive in all 10 hepatosplenic T-cell lymphoma cases tested, with a high mean fluorescence intensity. Fifty-six percent of T-cell large granular lymphocytic leukemia cases were positive for CD94 expression in a subset of neoplastic cells. All T-cell prolymphocytic leukemia and 97 % of peripheral T-cell lymphoma cases showed no CD94 expression. Our findings demonstrate a broad range of CD94 expression among T/NK-cell neoplasms, in some at levels that suggest therapeutic vulnerability to CD94-targeted therapies.

Repositioning Azelnidipine as a Dual Inhibitor Targeting CD47/SIRPα and TIGIT/PVR Pathways for Cancer Immuno-Therapy

Strategies boosting both innate and adaptive immunity have great application prospects in cancer immunotherapy. Antibodies dual blocking the innate checkpoint CD47 and adaptive checkpoint PD-L1 or TIGIT could achieve durable anti-tumor effects. However, a small molecule dual blockade of CD47/SIRPα and TIGIT/PVR pathways has not been investigated. Here, an elevated expression of CD47 and PVR was observed in tumor tissues and cell lines analyzed with the GEO datasets and by flow cytometry, respectively. Compounds approved by the FDA were screened with the software MOE by docking to the potential binding pockets of SIRPα and PVR identified with the corresponding structural analysis. The candidate compounds were screened by blocking and MST binding assays. Azelnidipine was found to dual block CD47/SIRPα and TIGIT/PVR pathways by co-targeting SIRPα and PVR. In vitro, azelnidipine could enhance the macrophage phagocytosis when co-cultured with tumor cells. In vivo, azelnidipine alone or combined with irradiation could significantly inhibit the growth of MC38 tumors. Azelnidipine also significantly inhibits the growth of CT26 tumors, by enhancing the infiltration and function of CD8⁺ T cell in tumor and systematic immune response in the tumor-draining lymph node and spleen in a CD8⁺ T cell dependent manner. Our research suggests that the anti-hypertensive drug azelnidipine could be repositioned for cancer immunotherapy.

Emerging immune checkpoints in the tumor microenvironment: Implications for cancer immunotherapy

Immune checkpoints within the tumor microenvironment (TME) play important roles in modulating host antitumor immunity. Checkpoint-based immunotherapies (e.g. immune checkpoint inhibitors) have revolutionized cancer therapy. However, there are still many drawbacks with current checkpoint immunotherapies in clinical practice, such as unresponsiveness, resistance, tumor hyperprogression, autoimmune-related adverse events, and limited efficacy with some solid malignances. These drawbacks highlight the need to further investigate the mechanisms underlying the therapeutic effects, as well as the need to identify new targets for cancer immunotherapy. With the discovery of emerging immune checkpoints in the TME, the development of strategies targeting the pivotal immunomodulators for cancer treatment has been significantly advanced in the past decade. In this review, we summarize and classify the novel emerging immune checkpoints beyond the extensively studied ones (e.g. PD-1, PD-L1, CTLA-4, LAG-3 and TIM-3) in the TME, and provide an update on the clinical trials targeting these key immune molecules.

Glioblastomas acquire myeloid-affiliated transcriptional programs via epigenetic immunoediting to elicit immune evasion

Glioblastoma multiforme (GBM) is an aggressive brain tumor for which current immunotherapy approaches have been unsuccessful. Here, we explore the mechanisms underlying immune evasion in GBM. By serially transplanting GBM stem cells (GSCs) into immunocompetent hosts, we uncover an acquired capability of GSCs to escape immune clearance by establishing an enhanced immunosuppressive tumor microenvironment. Mechanistically, this is not elicited via genetic selection of tumor subclones, but through an epigenetic immunoediting process wherein stable transcriptional and epigenetic changes in GSCs are enforced following immune attack. These changes launch a myeloid-affiliated transcriptional program, which leads to increased recruitment of tumor-associated macrophages. Furthermore, we identify similar epigenetic and transcriptional signatures in human mesenchymal subtype GSCs. We conclude that epigenetic immunoediting may drive an acquired immune evasion program in the most aggressive mesenchymal GBM subtype by reshaping the tumor immune microenvironment.

The landscape and prognostic value of immune characteristics in uterine corpus endometrial cancer

In the present study, we explored the clinical and immunological characteristics of 575 uterine corpus endometrial carcinoma (UCEC) samples obtained from The Cancer Genome Atlas (TCGA) using the ESTIMATE and CIBERSORT algorithms. First, Kaplan-Meier and univariate Cox regression analyses indicated that the immune cell score was a prognostic factor for overall survival (OS) and recurrence-free survival (RFS). Multivariate Cox regression analysis further revealed that the immune cell score was an independent prognostic factor for UCEC patients. Second, we investigated the correlation between the infiltration levels of 22 types of immune cells and the immune score. Survival analysis based on the 22 immune cell types showed that higher levels of regulatory T cell, activated NK cell, and follicular helper T-cell infiltration were associated with longer OS, while higher levels of CD8+ T cell and naive B-cell infiltration were associated with longer RFS. Next, we performed differential expression and prognosis analyses on 1534 immune-related genes and selected five from 14 candidate genes to construct a prognostic prediction model. The area under the receiver-operating characteristic (ROC) curve (AUC) for 3- and 5-year survival were 0.711 and 0.728, respectively. Further validation using a stage I-II subgroup showed similar results, presenting AUC values for 3- and five-year survival of 0.677 and 0.692, respectively. Taken together, the present study provides not only a deeper understanding of the relationship between UCEC and the immune landscape but also guidance for the future development of UCEC immunotherapy.

TNFR2: Role in Cancer Immunology and Immunotherapy

Immune checkpoint inhibitors (ICIs), including anti-CTLA-4 (cytotoxic T lymphocyte antigen-4) and anti-PD-1/PD-L1 (programmed death-1/programmed death-ligand 1), represent a turning point in the cancer immunotherapy. However, only a minor fraction of patients could derive benefit from such therapy. Therefore, new strategies targeting additional immune regulatory mechanisms are urgently needed. CD4⁺Foxp3⁺ regulatory T cells (Tregs) represent a major cellular mechanism in cancer immune evasion. There is compelling evidence that tumor necrosis factor (TNF) receptor type II (TNFR2) plays a decisive role in the activation and expansion of Tregs and other types of immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs). Furthermore, TNFR2 is also expressed by some tumor cells. Emerging experimental evidence indicates that TNFR2 may be a therapeutic target to enhance naturally occurring or immunotherapeutic-triggered anti-tumor immune responses. In this article, we discuss recent advances in the understanding of the mechanistic basis underlying the Treg-boosting effect of TNFR2. The role of TNFR2-expressing highly suppressive Tregs in tumor immune evasion and their possible contribution to the non-responsiveness to checkpoint treatment are analyzed. Moreover, the role of TNFR2 expression on tumor cells and the impact of TNFR2 signaling on other types of cells that shape the immunological landscape in the tumor microenvironment, such as MDSCs, MSCs, ECs, EPCs, CD8⁺ CTLs, and NK cells, are also discussed. The reports revealing the effect of TNFR2-targeting pharmacological agents in the experimental cancer immunotherapy are summarized. We also discuss the potential opportunities and challenges for TNFR2-targeting immunotherapy.

Extracellular Vesicles from Akkermansia muciniphila Elicit Antitumor Immunity Against Prostate Cancer via Modulation of CD8+ T Cells and Macrophages

PURPOSE

Prostate cancer (PCa) is one of the most common malignancies in males. Despite the success of immunotherapy in many malignant cancers, strategies are still needed to improve therapeutic efficacy in PCa. This study aimed to investigate the effects of Akkermansia muciniphila-derived extracellular vesicles (Akk-EVs) on PCa and elucidate the underlying immune-related mechanism.

METHODS

Akk-EVs were isolated by ultracentrifugation and intravenously injected to treat syngeneic PCa-bearing immune-competent mice. Immunophenotypic changes in immune cells, such as cytotoxic T lymphocytes and macrophages, were measured via flow cytometry analysis. Histological examination was used to detect morphological changes in major organs after Akk-EVs treatments. In vitro, flow cytometry was performed to confirm the effects of Akk-EVs on the activation of CD8+ T cells. Quantitative PCR and immunofluorescence staining were carried out to test the impact of Akk-EVs on macrophage polarization. Cell counting kit-8 (CCK-8) analysis, colony formation assays, and scratch wound healing assays were conducted to assess the effects of Akk-EVs-treated macrophages on the proliferation and invasion of PCa cells. CCK-8 assays also confirmed the impact of Akk-EVs on the viability of normal cells.

RESULTS

Intravenous injection of Akk-EVs in immune-competent mice reduced the tumor burden of PCa without inducing obvious toxicity in normal tissues. This treatment elevated the proportion of granzyme B-positive (GZMB+) and interferon γ-positive (IFN-γ+) lymphocytes in CD8+ T cells and caused macrophage recruitment, with increased tumor-killing M1 macrophages and decreased immunosuppressive M2 macrophages. In vitro, Akk-EVs increased the number of GZMB+CD8+ and IFN-γ+CD8+ T cells and M1-like macrophages. In addition, conditioned medium from Akk-EVs-treated macrophages suppressed the proliferation and invasion of prostate cells. Furthermore, the effective dose of Akk-EVs was well-tolerated in normal cells.

CONCLUSION

Our study revealed the promising prospects of Akk-EVs as an efficient and biocompatible immunotherapeutic agent for PCa treatment.

The Concept of Pathogenic TH2 Cells: Collegium Internationale Allergologicum Update 2021

T helper (TH) cells have evolved into distinct subsets that mediate specific immune responses to protect the host against a myriad of infectious and noninfectious challenges. However, if dysregulated, TH-cell subsets can cause inflammatory disease. Emerging evidence now suggests that human allergic disease is caused by a distinct subpopulation of pathogenic TH2 cells. Pathogenic TH2 cells from different type-2-driven diseases share a core phenotype and show overlapping functional attributes. The unique differentiation requirements, activating signals, and metabolic characteristics of pathogenic TH2 cells are just being discovered. A better knowledge of this particular TH2 cell population will enable the specific targeting of disease-driving pathways in allergy. In this review, we introduce a rational for classifying TH cells into distinct subsets, discuss the current knowledge on pathogenic TH2 cells, and summarize their involvement in allergic diseases.

PET Imaging of TIGIT Expression on Tumor-Infiltrating Lymphocytes

PURPOSE

Therapeutic checkpoint inhibitors on tumor-infiltrating lymphocytes (TIL) are being increasingly utilized in the clinic. The T-cell immunoreceptor with Ig and ITIM domains (TIGIT) is an inhibitory receptor expressed on T and natural killer cells. The TIGIT signaling pathway is an alternative target for checkpoint blockade to current PD-1/CTLA-4 strategies. Elevated TIGIT expression in the tumor microenvironment correlates with better therapeutic responses to anti-TIGIT therapies in preclinical models. Therefore, quantifying TIGIT expression in tumors is necessary for determining whether a patient may respond to anti-TIGIT therapy. PET imaging of TIGIT expression on TILs can therefore aid diagnosis and in monitoring therapeutic responses.

EXPERIMENTAL DESIGN

Antibody-based TIGIT imaging radiotracers were developed with the PET radionuclides copper-64 (⁶⁴Cu) and zirconium-89 (⁸⁹Zr). In vitro characterization of the imaging probes was followed by in vivo evaluation in both xenografts and syngeneic tumor models in mouse.

RESULTS

Two anti-TIGIT probes were developed and exhibited immunoreactivity of >72%, serum stability of >95%, and specificity for TIGIT with both mouse TIGIT-expressing HeLa cells and ex vivo-activated primary splenocytes. In vivo, the ⁸⁹Zr-labeled probe demonstrated superior contrast than the ⁶⁴Cu probe due to ⁸⁹Zr's longer half-life matching the TIGIT antibody's pharmacokinetics. The ⁸⁹Zr probe was used to quantify TIGIT expression on TILs in B16 melanoma in immunocompetent mice and confirmed by ex vivo flow cytometry.

CONCLUSIONS

This study develops and validates novel TIGIT-specific ⁶⁴Cu and ⁸⁹Zr PET probes for quantifying TIGIT expression on TILs for diagnosis of patient selection for anti-TIGIT therapies.

B7 Family Members in Lymphoma: Promising Novel Targets for Tumor Immunotherapy?

T cells play a vital role in the immune responses against tumors. Costimulatory or coinhibitory molecules regulate T cell activation. Immune checkpoint inhibitors, such as programmed cell death protein 1 (PD-1) and programmed death ligand 1 (PD-L1) have shown remarkable benefits in patients with various tumor, but few patients have displayed significant immune responses against tumors after PD-1/PD-L1 immunotherapy and many have been completely unresponsive. Thus, researchers must explore novel immune checkpoints that trigger durable antitumor responses and improve clinical outcomes. In this regard, other B7 family checkpoint molecules have been identified, namely PD-L2, B7-H2, B7-H3, B7-H4 and B7-H6. The aim of the present article was to address the expression, clinical significance and roles of B7 family molecules in lymphoma, as well as in T and NK cell-mediated tumor immunity. B7 family checkpoints may offer novel and immunotherapeutic strategies for patients with lymphoma.

Emerging role of autophagy in anti-tumor immunity: Implications for the modulation of immunotherapy resistance

Immunotherapies such as CAR-T cell transfer and antibody-targeted therapy have produced promising clinical outcomes in patients with advanced and metastatic cancer that are resistant to conventional therapies. However, with increasing use of cancer immunotherapy in clinical treatment, multiple therapy-resistance mechanisms have gradually emerged. The tumor microenvironment (TME), an integral component of cancer, can significantly influence the therapeutic response. Thus, it is worth exploring the potential of TME in modulating therapy resistance, in the hope to devise novel strategies to reinforcing anti-cancer treatments such as immunotherapy. As a crucial recycling process in the complex TME, the role of autophagy in tumor immunity has been increasingly appreciated. Firstly, autophagy in tumor cells can affect their immune response through modulating MHC-I-antigen complexes, thus modulating immunogenic tumor cell death, changing functions of immune cells via secretory autophagy, reducing the NK- and CTL-mediated cell lysis and degradation of immune checkpoint proteins. Secondly, autophagy is critical for the differentiation, maturation and survival of immune cells in the TME and can significantly affect the immune function of these cells, thereby regulating the anti-tumor immune response. Thirdly, alteration of autophagic activity in stromal cells, especially in fibroblasts, can reconstruct the three-dimensional stromal environment and metabolic reprogramming in the TME. A number of studies have demonstrated that optimal induction or inhibition of autophagy may lead to effective therapeutic regimens when combined with immunotherapy. This review discusses the important roles of autophagy in tumor cells, immune cells and stromal cells in the context of tumor immunity, and the potential of combining the autophagy-based therapy with immunotherapy as novel therapeutic approaches against cancer.

Comprehensive Analysis of Ferroptosis Regulators in Lung Adenocarcinomas Identifies Prognostic and Immunotherapy-Related Biomarkers

Ferroptosis is a newly discovered type of programmed cell death that differs from canonical apoptosis. However, the potential role of ferroptosis in lung adenocarcinoma (LUAD) has not been elaborated. In total, 1,328 samples from databases and 36 ferroptosis regulators were included in this study. By combining random survival forest and principal component analysis algorithms, a robust prognostic ferroptosis-related risk score (FRRS) was constructed, and the performance was validated in three independent datasets. Based on the median risk score, two subgroups were identified. Then, comparisons, including of mutational profiles, functional enrichment analyses and immune components, were conducted between subgroups. An immunotherapy cohort was applied to explore potential therapeutic-related biomarkers. Finally, the clinical utility of FRRS was validated in a proteomic cohort. In the TCGA-LUAD cohort, FRRS was calculated using the expression of 11 selected genes, and patients with high FRRS had a significantly (p < 0.001) worse prognosis than those with low FRRS. Multivariate regression suggested that FRRS was an independent prognostic factor. Functional enrichment analysis indicated that FRRS was mainly involved in cell cycle, metabolic and immune-related pathways. Furthermore, FRRS was shown to be significantly (p < 0.001) associated with the abundance of CD8 T cells and tumor mutation burden (TMB). The combination of TMB and FANCD2 expression, the main contributor to FRRS, substantially increased the precision of predicting the therapeutic response. In conclusion, the present study revealed the potential role of ferroptosis regulators in LUAD and identified ferroptosis-related biomarkers for prognostic and immunotherapeutic predictions.

Hypoxic Characteristic in the Immunosuppressive Microenvironment of Hepatocellular Carcinoma

Background: Generally, hepatocellular carcinoma (HCC) exists in an immunosuppressive microenvironment that promotes tumor evasion. Hypoxia can impact intercellular crosstalk in the tumor microenvironment. This study aimed to explore and elucidate the underlying relationship between hypoxia and immunotherapy in patients with HCC.

Methods: HCC genomic and clinicopathological datasets were obtained from The Cancer Genome Atlas (TCGA-LIHC), Gene Expression Omnibus databases (GSE14520) and International Cancer Genome Consortium (ICGC-LIRI). The TCGA-LIHC cases were divided into clusters based on single sample gene set enrichment analysis and hierarchical clustering. After identifying patients with immunosuppressive microenvironment with different hypoxic conditions, correlations between immunological characteristics and hypoxia clusters were investigated. Subsequently, a hypoxia-associated score was established by differential expression, univariable Cox regression, and lasso regression analyses. The score was verified by survival and receiver operating characteristic curve analyses. The GSE14520 cohort was used to validate the findings of immune cell infiltration and immune checkpoints expression, while the ICGC-LIRI cohort was employed to verify the hypoxia-associated score.

Results: We identified hypoxic patients with immunosuppressive HCC. This cluster exhibited higher immune cell infiltration and immune checkpoint expression in the TCGA cohort, while similar significant differences were observed in the GEO cohort. The hypoxia-associated score was composed of five genes (ephrin A3, dihydropyrimidinase like 4, solute carrier family 2 member 5, stanniocalcin 2, and lysyl oxidase). In both two cohorts, survival analysis revealed significant differences between the high-risk and low-risk groups. In addition, compared to other clinical parameters, the established score had the highest predictive performance at both 3 and 5 years in two cohorts.

Conclusion: This study provides further evidence of the link between hypoxic signals in patients and immunosuppression in HCC. Defining hypoxia-associated HCC subtypes may help reveal potential regulatory mechanisms between hypoxia and the immunosuppressive microenvironment, and our hypoxia-associated score could exhibit potential implications for future predictive models.

Identification of potential biomarkers associated with immune infiltration in the esophageal carcinoma tumor microenvironment

Tumor immune cell infiltration was significantly correlated with the progression and the effect of immunotherapy in cancers including esophageal carcinoma (ESCA). However, no biomarkers were identified which were associated with immune infiltration in ESCA. In the present study, a total of 128 common differentially expressed genes (DEGs) were identified between esophageal squamous cell carcinomas (ESCC) and esophageal adenocarcinomas (EAC). The results of gene ontology (GO) enrichment and Reactome pathway analysis displayed that the up-regulated DEGs were mainly involved in the regulation of extracellular matrix (ECM), while the down-regulated DEGs were mainly involved in the regulation of cornification and keratinocyte differentiation. The most significant module of up-regulated DEGs was selected by Molecular Complex Detection (MCODE). Top ten similar genes of COL1A2 were explored, then validation and the prognostic analysis of these genes displayed that COL1A2, COL1A1, COL3A1, ZNF469 and Periostin (POSTN) had the prognostic value which were up-regulated in ESCA. The expressions of COL1A2 and its four similar genes were mainly correlated with infiltrating levels of macrophages and dendritic cells (DCs) and showed strong correlations with diverse immune marker sets in ESCA. To summarize, COL1A2 and its four similar genes were identified as the potential biomarkers associated with immune infiltration in ESCA. These genes might be applied to immunotherapy for ESCA.

Insights into non-classic and emerging causes of hypopituitarism

Hypopituitarism is defined as one or more partial or complete pituitary hormone deficiencies, which are related to the anterior and/or posterior gland and can have an onset in childhood or adulthood. The most common aetiology is a sellar or suprasellar lesion, often an adenoma, which causes hypopituitarism due to tumour mass effects, or the effects of surgery and/or radiation therapy. However, other clinical conditions, such as traumatic brain injury, and autoimmune and inflammatory diseases, can result in hypopituitarism, and there are also genetic causes of hypopituitarism. Furthermore, the use of immune checkpoint inhibitors to treat cancer is increasing the risk of hypopituitarism, with a pattern of hormone defects that is different from the classic patterns and depends on mechanisms that are specific for each drug. Moreover, autoantibody production against the pituitary and hypothalamus has been demonstrated in studies investigating the development or worsening of some cases of hypopituitarism. Finally, evidence suggests that posterior pituitary damage can affect oxytocin secretion. The aim of this Review is to summarize current knowledge on non-classic and emerging causes of hypopituitarism, so as to help clinicians improve early identification, avoid life-threatening events and improve the clinical care and quality of life of patients at risk of hypopituitarism.

Harnessing NK cells for cancer immunotherapy: immune checkpoint receptors and chimeric antigen receptors

Natural killer (NK) cells, key antitumor effectors of the innate immune system, are endowed with the unique ability to spontaneously eliminate cells undergoing a neoplastic transformation. Given their broad reactivity against diverse types of cancer and close association with cancer prognosis, NK cells have gained considerable attention as a promising therapeutic target for cancer immunotherapy. NK cell-based therapies have demonstrated favorable clinical efficacies in several hematological malignancies but limited success in solid tumors, thus highlighting the need to develop new therapeutic strategies to restore and optimize antitumor activity while preventing tumor immune escape. The current therapeutic modalities yielding encouraging results in clinical trials include the blockade of immune checkpoint receptors to overcome the immune-evasion mechanism used by tumors and the incorporation of tumor-directed chimeric antigen receptors to enhance NK cell antitumor specificity and activity. These observations, together with recent advances in the understanding of NK cell activation within the tumor microenvironment, will facilitate the optimal design of NK cell-based therapy against a broad range of cancers and, more desirably, refractory cancers.

TIM-3 pathway dysregulation and targeting in cancer

INTRODUCTION

Dysfunction of the immune system is a hallmark of cancer. Through increased understanding of the complex interactions between immunity and cancer, immunotherapy has emerged as a treatment modality for different types of cancer. Promising activity with immunotherapy has been reported in numerous malignancies, but challenges such as limited response rates and treatment resistance remain. Furthermore, outcomes with this therapeutic approach in hematologic malignancies are even more limited than in solid tumors. T-cell immunoglobulin domain and mucin domain 3 (TIM-3) has emerged as a potential immune checkpoint target in both solid tumors and hematologic malignancies. TIM-3 has been shown to promote immune tolerance, and overexpression of TIM-3 is associated with more aggressive or advanced disease and poor prognosis.

AREAS COVERED

This review examines what is currently known regarding the biology of TIM-3 and clinical implications of targeting TIM-3 in cancer. Particular focus is given to myeloid malignancies.

EXPERT OPINION

The targeting of TIM-3 is a promising therapeutic approach in cancers, including hematologic cancers such as myeloid malignancies which have not benefited much from current immunotherapeutic treatment approaches. We anticipate that with further clinical evaluation, TIM-3 blockade will emerge as an important treatment strategy in myeloid malignancies.

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.

NAD+ Metabolism Maintains Inducible PD-L1 Expression to Drive Tumor Immune Evasion

NAD⁺ metabolism is implicated in aging and cancer. However, its role in immune checkpoint regulation and immune evasion remains unclear. Here, we find nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of the NAD⁺ biogenesis, drives interferon γ (IFNγ)-induced PD-L1 expression in multiple types of tumors and governs tumor immune evasion in a CD8⁺ T cell-dependent manner. Mechanistically, NAD⁺ metabolism maintains activity and expression of methylcytosine dioxygenase Tet1 via α-ketoglutarate (α-KG). IFNγ-activated Stat1 facilitates Tet1 binding to Irf1 to regulate Irf1 demethylation, leading to downstream PD-L1 expression on tumors. Importantly, high NAMPT-expressing tumors are more sensitive to anti-PD-L1 treatment and NAD⁺ augmentation enhances the efficacy of anti-PD-L1 antibody in immunotherapy-resistant tumors. Collectively, these data delineate an NAD⁺ metabolism-dependent epigenetic mechanism contributing to tumor immune evasion, and NAD⁺ replenishment combined with PD-(L)1 antibody provides a promising therapeutic strategy for immunotherapy-resistant tumors.

Homing Peptides for Cancer Therapy

Tumor-homing peptides are widely used for improving tumor selectivity of anticancer drugs and imaging agents. The goal is to increase tumor uptake and reduce accumulation at nontarget sites. Here, we describe current approaches for tumor-homing peptide identification and validation, and provide comprehensive overview of classes of tumor-homing peptides undergoing preclinical and clinical development. We focus on unique mechanistic features and applications of a recently discovered class of tumor-homing peptides, tumor-penetrating C-end Rule (CendR) peptides, that can be used for tissue penetrative targeting of extravascular tumor tissue. Finally, we discuss unanswered questions and future directions in the field of development of peptide-guided smart drugs and imaging agents.

Real-world safety experience with immune checkpoint inhibitors in Saudi Arabia

Lay abstract Real-world safety experience with immune checkpoint inhibitors in Saudi Arabia: Immune Checkpoint Inhibitors (ICIs) are rapidly growing and changing cancer care. With introduction of ICIs the landscape for cancer treatment has changed significantly. ICIs are known to induce immune-related adverse effects. This research is intended to shed light on ICIs and describe our safety experience with these agents. This study is a retrospective cohort study aimed to determine the safety of ICIs and its related adverse events at a tertiary hospital in Saudi Arabia. The study was conducted in the oncology center at King Abdulaziz Medical City, Riyadh. We identified study participants by using electronic health care system (BestCare)® to involve patients who received ICIs treatment during the study period from January 2016 up to December 2018, to include a total of 53 patients. Most of our patients were on nivolumab (37 patients) followed by atezolizumab (10 patients), and pembrolizumab (6 patients). The average number of emergency room visits after receiving treatment was three visits per patient. Renal adverse events occurred following ICIs use in nine patients, and none of the reported cases experienced a grade ≥3 event. Moreover, 13 patients experienced a hepatic adverse event, of whom only 1 patient experienced a grade ≥3 event leading to treatment discontinuation. As for diarrhea, among all patients who received ICIs, 14 patients experienced diarrhea, and 5 of them had grade ≥3 events. Also, thyroxine abnormalities occurred in seven patients. While, Pneumonitis occurred in four patients following ICIs use. In addition, we noticed other adverse events with ICIs including (skin reaction, nausea, vomiting, thrombocytopenia, neutropenia, and neurological adverse events). Furthermore, 17 patients required steroids to manage ICIs adverse events. And, no patients in our study required additional management with other immunosuppressive agents.Immunotherapies are rapidly growing and changing cancer care. Immune Checkpoint Inhibitors (ICIs) have the ability to block inhibitory checkpoints and restore the functions of the immune system. ICIs are used for the treatment of several types of cancer, and nowadays, many studies are ongoing in order to get approvals for newer indications. ICIs are known to induce immune-related adverse effects. The safety of ICIs and the most common immune-related adverse events are not yet well recognized for our population since this class of medications is lately introduced in our region, where only limited studies in our population are available in the literature. This research is intended to shed light on ICIs and describe our safety experience with these agents. This study is a retrospective cohort study aimed to determine the safety of ICIs and its related adverse events at a tertiary hospital in Saudi Arabia. The study was conducted in the oncology center at King Abdulaziz Medical City, Riyadh. Study participants were identified by using the electronic health care system (BestCare)® to include patients who were treated with ICIs during the study period from January 2016 up to December 2018. A total of 53 patients were included. Most of our patients were on nivolumab (37 patients) followed by atezolizumab (10 patients), and pembrolizumab (6 patients). The average number of emergency room visits after receiving ICIs was three visits per patient. Renal adverse events occurred following ICIs use in nine patients, and none of the reported cases experienced a grade ≥3 event. Moreover, 13 patients experienced a hepatic adverse event, of whom only 1 patient experienced a grade ≥3 event leading to treatment discontinuation. As for diarrhea, among all patients who received ICIs, 14 patients experienced diarrhea, and 5 of them had grade ≥3 events. Also, thyroxine abnormalities occurred in seven patients. While, pneumonitis occurred in four patients following ICIs use. In addition, we noticed other adverse events with ICIs, including (skin reaction, nausea, vomiting, thrombocytopenia, neutropenia, and neurological adverse events). Furthermore, 17 patients required steroids to manage ICIs adverse events. And, no patients in our study required additional management with other immunosuppressive agents. Patients treated with immune checkpoint inhibitors could have a variety of adverse drug events that might lead to treatment discontinuation and increase overall emergency room visits. This study highlights the most common adverse drug events associated with ICIs use at a tertiary care center in Saudi Arabia.

Novel Molecular Subtypes and Related Score Based on Histone Acetylation Modification in Renal Clear Cell Carcinoma

Background: Histone acetylation modification has been found to be correlated the development of renal carcinoma; however, its role in clear cell renal carcinoma (ccRCC) remains to be investigated. Thus, this study aimed to identify the molecular subtypes and establish a relevant score based on histone acetylation modification in ccRCC. Methods: Gene expression and mutation data were retrieved from The Cancer Genome Atlas database. Molecular subtypes were identified by unsupervised clustering based on histone acetylation regulators expression, and the molecular and clinical characteristics including survival, tumor microenvironment, gene set variation, immune cell infiltration, and immune checkpoints in each subtype were investigated. Next, we employed univariate Cox analysis to analyze these genes and established acetylation-related score by lasso regression analysis. Furthermore, we investigated the differences including survival, signaling pathways, mutational landscape, and tumor mutation burden (TMB) between high-risk and low-risk groups. The established score was validated by receiver operating curve and univariate and multivariate Cox regression analyses. We also established a nomogram including acetylation score, age, gender, grade, and stage and verified it by decision curve analysis and calibration plot. The E-MTAB-1980 cohort from the ArrayExpress database was employed as a reference to validate the established score. Results: Thirty-three types of histone acetylation regulators were employed in this study, and two clusters were identified. The two clusters presented significant differences in survival, tumor microenvironment, immune cell infiltration, immune checkpoints, and signaling pathways. Furthermore, an acetylation-related score, composed of six genes (BRD9, HDAC10, KAT2A, KAT5, BRDT, SIRT1, KAT6A, HDAC5), was verified to be significantly associated with prognosis and TMB. Thus, the established scores were successfully verified by the validated cohort, and the nomogram was constructed and successfully validated. Conclusion: The identification of the histone acetylation-related subtypes and score in our study may help reveal the potential relation between histone acetylation and immunity and provide novel insights for the development of individualized therapy for ccRCC.

Emerging Targets of Immunotherapy in Gynecologic Cancer

Although programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) and cytotoxic T lymphocyte antigen-4 (CTLA-4) have been successfully applied in the treatment of tumors, their efficiency is still not high enough. New immune targets need to be identified in order to seek alternative treatment strategies for patients with refractory tumors. Immune targets can be divided into stimulating and inhibiting molecules according to their function after receptor-ligand binding. We herein present a compendious summary of emerging immune targets in gynecologic tumors. These targets included coinhibitory molecules, such as T cell immunoglobulin-3 (TIM-3), T cell immunoglobulin and ITIM domain (TIGIT), lymphocyte activation gene-3 (LAG-3), V-type immunoglobulin domain-containing suppressor of T cell activation (VISTA), and B7-H3 and B7-H4, and co-stimulatory molecules, such as CD27, OX40, 4-1BB, CD40, glucocorticoid-induced tumor necrosis factor receptor (GITR) and inducible co-stimulator (ICOS). In this review, the characteristics and preclinical/clinical progress of gynecological malignancies are briefly discussed. However, the potential mechanisms and interactions of immune targets need to be elucidated in further studies.

Novel Molecular Subtypes Associated With 5mC Methylation and Their Role in Hepatocellular Carcinoma Immunotherapy

Background

5-methylcytosine (5mC) has been reported in the prognosis of a variety of cancers, however, its role in hepatocellular carcinoma (HCC) has not been investigated yet. This study aimed at identifying the molecular subtypes associated with 5mC and establishing a relevant score to predict its prognosis in HCC.

Methods

Somatic gene mutation data and gene expression data were retrieved from The Cancer Genome Atlas database. Molecular subtypes were identified by unsupervised clustering based on the expression of 5mC regulators, and the molecular features of each subtype were investigated by survival, mutation, gene set variation, and immune cell infiltration analyses. Next, we performed a differentially expressed analysis based on the new subtypes and selected the overlapping genes for further analysis. We undertook univariate Cox analysis to analyze these genes and constructed a prognostic model by lasso regression analysis. Meanwhile, survival and gene set enrichment analyses were used to explore the prognosis and the relevant pathways, respectively. The LIRI cohort from the International Cancer Genome Consortium database was used as a reference to validate the 5mC subtypes and 5mC score.

Results

Twenty-one types of 5mC regulators were employed in this study, and three 5mC-associated molecular subtypes were identified. These three subtypes presented significant differences in prognosis, immune cell infiltration, immune checkpoint inhibitors, signaling pathways, and mutational features. Compared with cluster 3, cluster 2 exhibited significantly increased expression of PD-L1, TIM3, Galectin9, CTLA4, and CD80, while PD-L1, TIM3, and CD80 were higher in cluster 2 than in cluster 1. Furthermore, a 5mC-related score, composed of seven genes (SGPP2, SALL4, B3GNT7, ROR1, MYBL2, SLC7A1, and CAND2), was proven to be significantly associated with prognosis. The established subtypes and scores were thus successfully verified by the validated cohort.

Conclusion

To the best of our knowledge, this is the first study to identify a novel molecular subtype based on 5mC regulators. The identification of the 5mC-associated subtype may help reveal the potential relation between 5mC and immunity and provide novel insights for the development of individualized therapy for HCC.

Liposome-Based Drug Delivery Systems in Cancer Immunotherapy

Cancer immunotherapy has shown remarkable progress in recent years. Nanocarriers, such as liposomes, have favorable advantages with the potential to further improve cancer immunotherapy and even stronger immune responses by improving cell type-specific delivery and enhancing drug efficacy. Liposomes can offer solutions to common problems faced by several cancer immunotherapies, including the following: (1) Vaccination: Liposomes can improve the delivery of antigens and other stimulatory molecules to antigen-presenting cells or T cells; (2) Tumor normalization: Liposomes can deliver drugs selectively to the tumor microenvironment to overcome the immune-suppressive state; (3) Rewiring of tumor signaling: Liposomes can be used for the delivery of specific drugs to specific cell types to correct or modulate pathways to facilitate better anti-tumor immune responses; (4) Combinational therapy: Liposomes are ideal vehicles for the simultaneous delivery of drugs to be combined with other therapies, including chemotherapy, radiotherapy, and phototherapy. In this review, different liposomal systems specifically developed for immunomodulation in cancer are summarized and discussed.

A guide to cancer immunotherapy: from T cell basic science to clinical practice

The T lymphocyte, especially its capacity for antigen-directed cytotoxicity, has become a central focus for engaging the immune system in the fight against cancer. Basic science discoveries elucidating the molecular and cellular biology of the T cell have led to new strategies in this fight, including checkpoint blockade, adoptive cellular therapy and cancer vaccinology. This area of immunological research has been highly active for the past 50 years and is now enjoying unprecedented bench-to-bedside clinical success. Here, we provide a comprehensive historical and biological perspective regarding the advent and clinical implementation of cancer immunotherapeutics, with an emphasis on the fundamental importance of T lymphocyte regulation. We highlight clinical trials that demonstrate therapeutic efficacy and toxicities associated with each class of drug. Finally, we summarize emerging therapies and emphasize the yet to be elucidated questions and future promise within the field of cancer immunotherapy.

Genetic Mutations of Tim-3 Ligand and Exhausted Tim-3+ CD8+ T Cells and Survival in Diffuse Large B Cell Lymphoma

Tim-3 is a promising target for antitumor immunotherapy. A number of clinical trials are evaluating the efficacy of anti-Tim-3 therapies as a single agent or combinations in solid tumors and haematologic malignancies. However, there remains a considerable lack of data on Tim-3 signalling, especially the genetic characteristics and immune microenvironment, in diffuse large B cell lymphoma (DLBCL). Herein, we identified three genetic mutations in galectin-9, a major ligand of Tim-3, in six patients with DLBCL (6/188, 3.2%) that were not detected in the COSMIC database. The Oncomine database showed that the mRNA levels of Tim-3 were higher in DLBCL cells than those in normal B cells. Multiplexed immunofluorescence revealed that patients with Tim-3-expressing tumor-infiltrating lymphocytes (Tim-3⁺ TILs) exhibited poor outcomes than those with Tim-3⁻ TILs (p = 0.041). The median survival times of these patients were 65.0 (95% confidence interval (CI): 71.2–88.6) and 79.9 months (95% CI: 54.4–75.6), respectively. Furthermore, we defined a novel subtype of exhausted T cells, named as exhausted Tim-3⁺ CD8⁺ T cells, and found that patients with exhausted Tim-3⁺ CD8⁺ T cells (median survival, 62.8 months, 95% CI: 50.0–75.6) exhibited shorter survival than those with nonexhausted Tim-3⁻ CD8⁺ T cells (median survival, 82.5 months, 95% CI: 72.0–92.9; p = 0.034). Overall, these findings provide the genetic status of the Tim-3 ligand in DLBCL. Patients with Tim-3⁺ TILs and exhausted Tim-3⁺ CD8⁺ T cells exhibited inferior survival, thus highlighting the possibility of potential therapeutic applications of the inhibition of Tim-3 alone or in combination with other immune checkpoints for treatment of patients with DLBCL.

Immune checkpoint molecules in natural killer cells as potential targets for cancer immunotherapy

Recent studies have demonstrated the potential of natural killer (NK) cells in immunotherapy to treat multiple types of cancer. NK cells are innate lymphoid cells that play essential roles in tumor surveillance and control that efficiently kill the tumor and do not require the major histocompatibility complex. The discovery of the NK's potential as a promising therapeutic target for cancer is a relief to oncologists as they face the challenge of increased chemo-resistant cancers. NK cells show great potential against solid and hematologic tumors and have progressively shown promise as a therapeutic target for cancer immunotherapy. The effector role of these cells is reliant on the balance of inhibitory and activating signals. Understanding the role of various immune checkpoint molecules in the exhaustion and impairment of NK cells when their inhibitory receptors are excessively expressed is particularly important in cancer immunotherapy studies and clinical implementation. Emerging immune checkpoint receptors and molecules have been found to mediate NK cell dysfunction in the tumor microenvironment; this has brought up the need to explore further additional NK cell-related immune checkpoints that may be exploited to enhance the immune response to refractory cancers. Accordingly, this review will focus on the recent findings concerning the roles of immune checkpoint molecules and receptors in the regulation of NK cell function, as well as their potential application in tumor immunotherapy.

A Structure-Activity Relationship Study of Novel Hydroxamic Acid Inhibitors around the S1 Subsite of Human Aminopeptidase N

Aminopeptidase N (APN/CD13) is a zinc-dependent ubiquitous transmembrane ectoenzyme that is widely present in different types of cells. APN is one of the most extensively studied metalloaminopeptidases as an anti-cancer target due to its significant role in the regulation of metastasis and angiogenesis. Previously, we identified a potent and selective APN inhibitor, N-(2-(Hydroxyamino)-2-oxo-1-(3',4',5'-trifluoro-[1,1'-biphenyl]-4-yl)ethyl)-4-(methylsulfonamido)benzamide (3). Herein, we report the further modifications performed to explore SAR around the S1 subsite of APN and to improve the physicochemical properties. A series of hydroxamic acid analogues were synthesised, and the pharmacological activities were evaluated in vitro. N-(1-(3'-Fluoro-[1,1'-biphenyl]-4-yl)-2-(hydroxyamino)-2-oxoethyl)-4-(methylsulfonamido)benzamide (6 f) was found to display an extremely potent inhibitory activity in the sub-nanomolar range.

Significantly different immunological score in lung adenocarcinoma and squamous cell carcinoma and a proposal for a new immune staging system

TNM stage is not enough to accurately predict the prognosis of patients with non-small cell lung cancer (NSCLC). This study aimed to establish the immunological score (IS) in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC), separately, and propose a new staging system in NSCLC. We used the multiplex fluorescent immunohistochemistry (mIHC) technology to detect 17 immune biomarkers of 304 patients with NSCLC. The LASSO-COX regression model was used to establish the IS_NSCLC in the training cohorts. The IS_NSCLC was then validated in the validation cohort. The constructed IS_LUAD contained three immune features: CD4⁺CD73⁺ _{core of tumor (CT)}, PD-L1⁺ _CT, and IDO⁺ _{invasive margin (IM)}. IS_LUSC also contained two immune features: CD8⁺CD39^-CD73^- _CT, CD8⁺Tim-3⁺ _IM. In the training cohort, significant prognostic differences were found upon comparing low-IS_NSCLC patients with high-IS_NSCLC patients. For LUAD, the 5-y disease-free survival (DFS) rates were 54.7% vs. 8.1% and the 5-y overall survival (OS) rates were 82.4% vs. 36% (all P< .0001). For LUSC, the 5-y DFS rates were 74.0% vs. 14.7% and the 5-y OS rates were 78.2% vs. 17.6% (all P< .0001). Multivariate analyses indicated that IS_NSCLC was an independent indicator for prognosis. Finally, we combined IS_NSCLC with clinicopathological factors to establish a TN-I staging system and two nomogram models for clinical use. The TN-I stage had better prediction accuracy than TNM stage. The newly established IS_LUAD and IS_LUSC were completely different, and both were excellent indicators for the prognostic prediction. The TN-I stage could effectively improve prognostic accuracy and facilitate clinical application. Abbreviations NSCLC, non-small cell lung cancer; IS, immunological score; mIHC, multiplex fluorescent immunohistochemistry; LUAD, lung adenocarcinoma; LUSC, lung squamous cell carcinoma; CT, core of tumor; IM, invasive margin; DFS, disease-free survival; OS, overall survival; SITC, the Society for Immunotherapy of Cancer; FFPE, formalin-fixed paraffin-embedded; MWT, microwave treatment; DCA, decision curve analysis; ROC, receiver operating characteristic; AUC, area under the curve; EGFR, epidermal growth factor receptor.

Characteristics of anti-CD19 CAR T cell infusion products associated with efficacy and toxicity in patients with large B cell lymphomas

Autologous chimeric antigen receptor (CAR) T cell therapies targeting CD19 have high efficacy in large B cell lymphomas (LBCLs), but long-term remissions are observed in less than half of patients, and treatment-associated adverse events, such as immune effector cell-associated neurotoxicity syndrome (ICANS), are a clinical challenge. We performed single-cell RNA sequencing with capture-based cell identification on autologous axicabtagene ciloleucel (axi-cel) anti-CD19 CAR T cell infusion products to identify transcriptomic features associated with efficacy and toxicity in 24 patients with LBCL. Patients who achieved a complete response by positron emission tomography/computed tomography at their 3-month follow-up had three-fold higher frequencies of CD8 T cells expressing memory signatures than patients with partial response or progressive disease. Molecular response measured by cell-free DNA sequencing at day 7 after infusion was significantly associated with clinical response (P = 0.008), and a signature of CD8 T cell exhaustion was associated (q = 2.8 × 10^-149) with a poor molecular response. Furthermore, a rare cell population with monocyte-like transcriptional features was associated (P = 0.0002) with high-grade ICANS. Our results suggest that heterogeneity in the cellular and molecular features of CAR T cell infusion products contributes to variation in efficacy and toxicity after axi-cel therapy in LBCL, and that day 7 molecular response might serve as an early predictor of CAR T cell efficacy.

New insights into the interaction of the immune system with non-small cell lung carcinomas

The basis of current and future lung cancer immunotherapy depends mainly on our knowledge of the molecular mechanisms of interactions between cancer and immune cells (ICs), as well as on interactions occurring between the different populations of intra-tumor ICs. These interactions are very complex, as virtually all immune cell types, including macrophages, neutrophils, mast cells, natural killer (NK) cells, dendritic cells and T and B lymphocytes can infiltrate lung cancer tissues at the same time. Moreover these interactions lead to progressive emergence of an imbalance in ICs. Initially ICs have an anti-tumor effect but then induce immune tolerance and eventually tumor progression and dissemination. All the cells of innate and adaptive intra-tumor immunity engage in this progressive phenotypic switch. A majority of non-small cell lung carcinoma (NSCLC) patients do not benefit from the expected positive responses associated with current immunotherapy. Thus, there is urgent need to better understand the different roles of the associated cancer ICs. This review summarizes some of the new insights into this domain, with particular focus on: the myeloid cell population associated with tumors, the tertiary lymphoid structures (TLSs), the role of the P2 purinergic receptors (P2R) and ATP, and the new concept of the “liquid microenvironment” implying blood circulating ICs.

IFI30 expression is an independent unfavourable prognostic factor in glioma

Gamma-interferon-inducible lysosomal thiol reductase, the only known lysosomal thiol reductase, is encoded by gene IFI30 and expressed constitutively in antigen-presenting cells. Our comprehensive study on IFI30 in gliomas found its expression to be high in glioblastomas and in gliomas with a mesenchymal subtype or wild-type isocitrate dehydrogenase, all of which indicated the malignancy and poor outcomes of gliomas. Kaplan-Meier survival analysis ascertained that high IFI30 expression conferred poor outcomes. The IFI30 expression levels also showed high efficiency in predicting 1-, 3- and 5-year overall survival. Univariable and multivariable Cox regression analyses were performed to define IFI30 as an independent prognostic marker. Biological process analysis suggested that IFI30 was involved in immune responses. ESTIMATE and CIBERSORT were applied to evaluate immune cell infiltration, with results indicating that samples with higher IFI30 expression had higher infiltration of immune cells, including regulatory T cells and M0 macrophages. Correlation analysis showed that IFI30 was significantly positively correlated with immune checkpoints that suppress effective antitumour immune responses. Immunohistochemical staining was also performed to confirm the association between IFI30 expression and the immune phenotype. The suggested correlation between high IFI30 expression and an immunosuppressive phenotype contributes to our knowledge about the glioma microenvironment and might provide clues for the development of novel therapeutic targets.

Noninvasive quantification of target availability during therapy using paired-agent fluorescence tomography

Immuno-oncological treatment strategies that target abnormal receptor profiles of tumors are an increasingly important feature of cancer therapy. Yet, assessing receptor availability (RA) and drug-target engagement, important determinants of therapeutic efficacy, is challenging with current imaging strategies, largely due to the complex nonspecific uptake behavior of imaging agents in tumors. Herein, we evaluate whether a quantitative noninvasive imaging approach designed to compensate for nonspecific uptake, MRI-coupled paired-agent fluorescence tomography (MRI-PAFT), is capable of rapidly assessing the availability of epidermal growth factor receptor (EGFR) in response to one dose of anti-EGFR antibody therapy in orthotopic brain tumor models.

Methods: Mice bearing orthotopic brain tumor xenografts with relatively high EGFR expression (U251) (N=10) or undetectable human EGFR (9L) (N=9) were considered in this study. For each tumor type, mice were either treated with one dose of cetuximab, or remained untreated. All animals were scanned using MRI-PAFT, which commenced immediately after paired-agent administration, and values of RA were recovered using a model-based approach, which uses the entire dynamic sequence of agent uptake, as well as a simplified “snapshot” approach which requires uptake measurements at only two time points. Recovered values of RA were evaluated between groups and techniques. Hematoxylin & eosin (H&E) and immunohistochemical (IHC) staining was performed on tumor specimens from every animal to confirm tumor presence and EGFR status.

Results: In animals bearing EGFR(+) tumors, a significant difference in RA values between treated and untreated animals was observed (RA = 0.24 ± 0.15 and 0.61 ± 0.18, respectively, p=0.027), with an area under the curve - receiver operating characteristic (AUC-ROC) value of 0.92. We did not observe a statistically significant difference in RA values between treated and untreated animals bearing EGFR(-) tumors (RA = 0.18 ± 0.19 and 0.27 ± 0.21, respectively; p = 0.89; AUC-ROC = 0.55), nor did we observe a difference between treated EGFR(+) tumors compared to treated and untreated EGFR(-) tumors. Notably, the snapshot paired-agent strategy quantified drug-receptor engagement within just 30 minutes of agent administration. Examination of the targeted agent alone showed no capacity to distinguish tumors either by treatment or receptor status, even 24h after agent administration.

Conclusions: This study demonstrated that a noninvasive imaging strategy enables rapid quantification of receptor availability in response to therapy, a capability that could be leveraged in preclinical drug development, patient stratification, and treatment monitoring.

Progress of immune checkpoint LAG-3 in immunotherapy

Immune checkpoint inhibition has been shown to successfully reactivate T cell responses directed against tumor-associated antigens, resulting in significantly prolonged overall survival in patients with various types of solid tumors. Among them, cytotoxic T-lymphocyte protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) play key roles in tumor immune escape and are well-established targets of cancer immunotherapy. However, the low response rate PD-1 and CTLA-4 is a limitation and a challenge. Hence, studies have focused on investigating the tumor microenvironment for alternative therapeutic targets. Lymphocyte activation gene 3 protein (LAG-3) negatively regulates T lymphocytes by binding to the extracellular domain of the ligand, thus avoiding autoimmunity caused by T cell overactivation. LAG-3 is an important immune checkpoint in vivo and plays a balanced regulatory role in the human immune system. LAG-3 is now regarded as a new generation of immunotherapy targets. The present review describes the research progress of LAG-3 to provide reference for further investigation of LAG-3. The immune checkpoint of LAG-3 plays a crucial role in cancer development and may be used in future clinical practice of cancer therapy.

A Cross-Species Reactive TIGIT-Blocking Antibody Fc Dependently Confers Potent Antitumor Effects

The T cell immunoreceptor with Ig and ITIM domains (TIGIT) has been shown to exert inhibitory roles in antitumor immune responses. In this study, we report the development of a human mAb, T4, which recognizes both human and mouse TIGIT and blocks the interaction of TIGIT with its ligand CD155 in both species. The T4 Ab targets the segment connecting F and G strands of TIGIT's extracellular IgV domain, and we show in studies with mouse tumor models that the T4 Ab exerts strong antitumor activity and induces durable immune memory against various tumor types. Mechanistically, we demonstrate that the T4 Ab's antitumor effects are mediated via multiple immunological impacts, including a CD8⁺ T immune response and Fc-mediated effector functions, through NK cells that cause significant reduction in the frequency of intratumoral T regulatory cells (Tregs). Notably, this Treg reduction apparently activates additional antitumor CD8⁺ T cell responses, targeting tumor-shared Ags that are normally cryptic or suppressed by Tregs, thus conferring cross-tumor immune memory. Subsequent engineering for Fc variants of the T4 Ab with enhanced Fc-mediated effector functions yielded yet further improvements in antitumor efficacy. Thus, beyond demonstrating the T4 Ab as a promising candidate for the development of cancer immunotherapies, our study illustrates how the therapeutic efficacy of an anti-TIGIT Ab can be improved by enhancing Fc-mediated immune effector functions. Our insights about the multiple mechanisms of action of the T4 Ab and its Fc variants should help in developing new strategies that can realize the full clinical potential of anti-TIGIT Ab therapies.

Novel strategies in immune checkpoint inhibitor drug development: How far are we from the paradigm shift?

The development of immune checkpoint inhibitors (ICI) represents a major milestone in immune-oncology. Over the years these agents have demonstrated efficacy in an increasing array of malignancies. Despite this success however, significant challenges remain. Novel approaches to both drug development and trial design are required to incorporate the unique pharmacokinetic and pharmacodynamic properties of ICIs. Further, it has also been established that the benefit of ICIs is limited to only a subset of patients. The molecular interactions between native immune cells and tumorigenesis and progression represent an active area of biomarker research, and elucidating the mechanisms of response and resistance is crucial to develop rational trial designs for the next wave of immune-oncology (IO) clinical trials, particularly in patients with primary and/or acquired resistance. Efforts are now being made to integrate both biological and clinical information using novel multi-omic approaches which are now being developed to further elucidate the molecular signatures associated with IO treatment response and resistance and enable rational drug development and trial design processes. As such, precision IO and the ability to deliver patient-specific choices for ICI monotherapies or combination therapies has become an increasingly tangible goal. We herein describe the current landscape in ICI drug development and discuss the challenges and future directions in this exciting and evolving era in immune-oncology.

Evaluation of glucocorticoid-induced TNF receptor (GITR) expression in breast cancer and across multiple tumor types

Glucocorticoid-induced TNF receptor (GITR) is an emerging immunotherapy target that is expressed at high levels on regulatory T cells. Agonistic anti-GITR antibodies have anti-tumor activity in cancer mouse models, and recent phase 1 trials have demonstrated their safe pharmacological profile. However, there is limited knowledge on the relationship between GITR expression and the tumor microenvironment. GITR protein expression was assayed by immunohistochemistry on 3992 breast cancer surgical excision specimens assembled into tissue microarrays and scored visually by a pathologist for GITR expression on tumor-infiltrating lymphocytes and on carcinoma cells. GITR expression by the malignant cells was further surveyed in gastrointestinal stromal tumor (N = 713), lung carcinoma (N = 705), pancreatic cancer (N = 486), ovarian cancer (N = 445), bladder cancer (N = 88), prostate cancer (N = 88), testicular cancer (N = 76), melanoma (N = 75), renal cell carcinoma (N = 68),  epithelioid sarcoma (N = 53), and neuroendocrine tumors (N = 41). In breast cancer, GITR expression on tumor-infiltrating lymphocytes (12.4%) correlated with other immune response biomarkers (PD-L1+ on tumor cells, and PD-1+, LAG-3+, TIM-3+ lymphocytes; p < 0.001), and T-cell markers (CD8+, FOXP3+; p < 0.001). GITR+ carcinoma cells were observed in 6.0% of breast cancer cases and correlated with worse relapse-free survival (p = 0.015). Among the additional tumor types examined, cancers with GITR+ malignant cells included bladder cancer (5.7%), primary (but not metastatic) melanoma (4.5%), and ovarian cancer (3.2%); no expression was identified among examined sarcomas. To our knowledge, this is the first immunohistochemistry study to report the frequency and pattern of GITR expression in a large breast cancer cohort, or to report membranous GITR expression on malignant cells. The co-infiltration of GITR with other immune biomarkers and T-cell markers supports a potential role for anti-GITR agents in combination immunotherapies. In addition, GITR expression on carcinoma cells could imply the existence of a novel cancer immune evasion strategy worthy of further investigation.

B7-H3 Immune Checkpoint Protein in Human Cancer

B7-H3 belongs to the B7 family of immune checkpoint proteins, which are important regulators of the adaptive immune response and emerging key players in human cancer. B7-H3 is a transmembrane protein expressed on the surface of tumor cells, antigen presenting cells, natural killer cells, tumor endothelial cells, but can also be present in intra- and extracellular vesicles. Additionally, B7-H3 may be present as a circulating soluble isoform in serum and other body fluids. B7-H3 is overexpressed in a variety of tumor types, in correlation with poor prognosis. B7-H3 is a promising new immunotherapy target for anti-cancer immune response, as well as a potential biomarker. Besides its immunoregulatory role, B7-H3 has intrinsic pro-tumorigenic activities related to enhanced cell proliferation, migration, invasion, angiogenesis, metastatic capacity and anti-cancer drug resistance. B7-H3 has also been found to regulate key metabolic enzymes, promoting the high glycolytic capacity of cancer cells. B7-H3 receptors are still not identified, and little is known about the molecular mechanisms underlying B7-H3 functions. Here, we review the current knowledge on the involvement of B7-H3 in human cancer.