Increased Intratumoral FOXP3-positive Regulatory Immune Cells during Interleukin-2 Treatment in Metastatic Renal Cell Carcinoma

Immune phenotype-genotype associations in primary clear cell renal cell carcinoma and matched metastatic tissue

Adjuvant immunotherapy has been recently recommended for patients with metastatic ccRCC, but there are no tissue biomarkers to predict treatment response in ccRCC. Potential predictive biomarkers are mainly assessed in primary tumor tissue, whereas metastases remain understudied. To explore potential differences between genomic alterations and immune phenotypes in primary tumors and their matched metastases, we analyzed primary tumors (PTs) of 47 ccRCC patients and their matched distant metastases (METs) by comprehensive targeted parallel sequencing, whole-genome copy number variation (CNV) analysis, determination of microsatellite instability (MSI) and tumor mutational burden (TMB). We quantified the spatial distribution of tumor-infiltrating CD8+ T cells, and co-expression of the T-cell-exhaustion marker TOX by digital immunoprofiling and quantified tertiary lymphoid structures (TLS). Most METs were pathologically "cold". Inflamed, pathologically "hot" PTs were associated with a decreased disease-free survival (DFS), worst for patients with high levels of CD8+TOX+ T cells. Interestingly, inflamed METs showed a relative increase of exhausted CD8+TOX+ T cells and increased accumulative size of TLS compared to PTs. Integrative analysis of molecular and immune phenotypes revealed BAP1 and CDKN2A/B deficiency to be associated with an inflamed immune phenotype. Our results highlight the distinct spatial distribution and differentiation of CD8+ T cells at metastatic sites, and the association of an inflamed microenvironment with specific genomic alterations.

Quantification of CD3, FoxP3, and granzyme B immunostaining in canine renal cell carcinoma

Tumor-infiltrating lymphocyte (TIL) density plays an important role in anti-tumor immunity and is associated with patient outcome in various human and canine malignancies. As a first assessment of the immune landscape of the tumor microenvironment in canine renal cell carcinoma (RCC), we retrospectively analyzed clinical data and quantified CD3, FoxP3, and granzyme B immunostaining in formalin-fixed paraffin-embedded tumor samples from 16 dogs diagnosed with renal cell carcinoma treated with ureteronephrectomy. Cell density was low for all markers evaluated. Increased numbers of intratumoral FoxP3 labelled (+) cells, as well as decreased granzyme B+: FoxP3+ TIL ratio, were associated with poor patient outcomes. Our initial study of canine RCC reveals that these tumors are immunologically cold and Tregs may play an important role in immune evasion.

Development of an Immune Prognostic Model for Clear Cell Renal Cell Carcinoma Based on Tumor Microenvironment

Immune infiltration remains at a high level in clear cell renal cell carcinoma (ccRCC). It has been confirmed that immune cell infiltration in tumor microenvironment (TME) is intimately bound up with the progression and the clinical outcome of ccRCC. The prognostic model, developed based on different immune subtypes of ccRCC, has a predictive value in patients' prognosis. RNA sequencing data, somatic mutation data of ccRCC and clinical information were acquired from the cancer genome atlas (TCGA) database. The key immune-related genes (IRGs) were selected and by univariate Cox, LASSO, and multivariate Cox regression analyses. Then the ccRCC prognostic model was developed. The applicability of this model was verified in the independent dataset GSE29609. Thirteen IRGs including CCL7, ATP6V1C2, ATP2B3, ELAVL2, SLC22A8, DPP6, EREG, SERPINA7, PAGE2B, ADCYAP1, ZNF560, MUC20, and ANKRD30A were finally selected and a 13-IRGs prognostic model was developed. Survival analysis demonstrated that when compared with the low-risk group, patients in the high-risk group had a lower overall survival (p<0.05). AUC values based on the 13-IRGs prognostic model used to predict 3- and 5-year survival of ccRCC patients were greater than 0.70. And risk score was an independent prognostic factor (p<0.001). In addition, nomogram could accurately predict ccRCC patient's prognosis. This 13-IRGs model can effectively evaluate the prognosis of ccRCC patients, and also provide guidance for the treatment and prognosis of ccRCC patients.

Advances in the Lung Cancer Immunotherapy Approaches

Despite the progress in the comprehension of LC progression, risk, immunologic control, and treatment choices, it is still the primary cause of cancer-related death. LC cells possess a very low and heterogeneous antigenicity, which allows them to passively evade the anticancer defense of the immune system by educating cytotoxic lymphocytes (CTLs), tumor-infiltrating lymphocytes (TILs), regulatory T cells (Treg), immune checkpoint inhibitors (ICIs), and myeloid-derived suppressor cells (MDSCs). Though ICIs are an important candidate in first-line therapy, consolidation therapy, adjuvant therapy, and other combination therapies involving traditional therapies, the need for new predictive immunotherapy biomarkers remains. Furthermore, ICI-induced resistance after an initial response makes it vital to seek and exploit new targets to benefit greatly from immunotherapy. As ICIs, tumor mutation burden (TMB), and microsatellite instability (MSI) are not ideal LC predictive markers, a multi-parameter analysis of the immune system considering tumor, stroma, and beyond can be the future-oriented predictive marker. The optimal patient selection with a proper adjuvant agent in immunotherapy approaches needs to be still revised. Here, we summarize advances in LC immunotherapy approaches with their clinical and preclinical trials considering cancer models and vaccines and the potential of employing immunology to predict immunotherapy effectiveness in cancer patients and address the viewpoints on future directions. We conclude that the field of lung cancer therapeutics can benefit from the use of combination strategies but with comprehension of their limitations and improvements.

PPP2R2D Suppresses Effector T Cell Exhaustion and Regulatory T Cell Expansion and Inhibits Tumor Growth in Melanoma

We had shown previously that the protein phosphatase 2A regulatory subunit PPP2R2D suppresses IL-2 production, and PPP2R2D deficiency in T cells potentiates the suppressive function of regulatory T (Treg) cells and alleviates imiquimod-induced lupus-like pathology. In this study, in a melanoma xenograft model, we noted that the tumor grew in larger sizes in mice lacking PPP2R2D in T cells (LckCreR2Dfl/fl) compared with wild type (R2Dfl/fl) mice. The numbers of intratumoral T cells in LckCreR2Dfl/fl mice were reduced compared with R2Dfl/fl mice, and they expressed a PD-1+CD3+CD44+ exhaustion phenotype. In vitro experiments confirmed that the chromatin of exhaustion markers PD-1, LAG3, TIM3, and CTLA4 remained open in LckCreR2Dfl/fl CD4 T conventional compared with R2Dfl/fl T conventional cells. Moreover, the percentage of Treg cells (CD3+CD4+Foxp3+CD25hi) was significantly increased in the xenografted tumor of LckCreR2Dfl/fl mice compared with R2Dfl/fl mice probably because of the increase in the percentage of IL-2-producing LckCreR2Dfl/fl T cells. Moreover, using adoptive T cell transfer in mice xenografted with melanoma, we demonstrated that PPP2R2D deficiency in T cells enhanced the inhibitory effect of Treg cells in antitumor immunity. At the translational level, analysis of publicly available data from 418 patients with melanoma revealed that PPP2R2D expression levels correlated positively with tumor-infiltration level of CD4 and CD8 T cells. The data demonstrate that PPP2R2D is a negative regulator of immune checkpoint receptors, and its absence exacerbates effector T cell exhaustion and promotes Treg cell expansion. We conclude that PPP2R2D protects against melanoma growth, and PPP2R2D-promoting regimens can have therapeutic value in patients with melanoma.

Selective delivery of low-affinity IL-2 to PD-1+ T cells rejuvenates antitumor immunity with reduced toxicity

PD-1 signaling on T cells is the major pathway that limits T cell immunity, but the efficacy of anti–PD-1 therapy has been limited to a small proportion of patients with advanced cancers. We fortuitously observed that anti–PD-1 therapy depends on IL-2 signaling, which raises the possibility that a lack of IL-2 limits anti–PD-1–induced effector T cell expansion. To selectively deliver IL-2 to PD-1⁺CD8⁺ tumor-infiltrating lymphocytes (TILs), we engineered a low-affinity IL-2 paired with anti–PD-1 (PD-1–laIL-2), which reduced affinity to peripheral Treg cells but enhanced avidity to PD-1⁺CD8⁺ TILs. PD-1–laIL-2 exerted better tumor control and lower toxicity than single or mixed treatments. Mechanistically, PD-1–laIL-2 could effectively expand dysfunctional and tumor-specific CD8⁺ T cells. Furthermore, we discovered that presumably dysfunctional PD-1⁺TIM3⁺ TILs are the dominant tumor-specific T cells responding to PD-1–laIL-2. Collectively, these results highlight that PD-1–laIL-2 can target and reactivate tumor-specific TILs for tumor regression as a unique strategy with stronger efficacy and lower toxicity.

The intra-class heterogeneity of immunophenotyping and immune landscape in oesophageal cancer and clinical implications

BACKGROUND

The response rate and survival benefit of immunotherapy vary among patients, implying specific immune status of an individual could be associated with the effect of immunotherapy. However, in-depth studies of immune subtypes (ISs), immune landscape and tumour microenvironment of oesophageal cancer (ESCA) and their clinical implications are less reported.

METHODS

We first accessed data from publicly available databases and preprocessed it based on a standard protocol. Then, ISs were identified by unsupervised learning. Thereafter, the association of these ISs and tumour mutation burden (TMB), biomarkers of chemotherapy-induced immune response, tumour markers were also assessed. In addition, the immune characteristics, immune landscape, co-expression network of immune genes, and clinical implications were visualized and analysed.

RESULTS

We identified three immunoclusters based on immune-associated genes with intra-class heterogeneity and prognostic value. Cluster-specific associations with TMB, markers of chemotherapy-induced immune response, and tumour markers were revealed. A 4-gene signature (risk score= -0.16514291×BHLHE22-0.03964046×MXRA8-0.15242778×SLIT2-0.05553572×SPON1) based on co-expressed genes in the immunoclusters was developed and externally validated.

CONCLUSIONS

In summary, we identified clinically relevant immunoclusters in both adenocarcinoma and squamous cell carcinoma of oesophagus, revealing the necessity of assessing the complexity and diversity of immune microenvironment for cancer immunotherapy.

Updates on Immunotherapy and Immune Landscape in Renal Clear Cell Carcinoma

Several clinicopathological features of clear cell renal cell carcinomas (ccRCC) contribute to make an "atypical" cancer, including resistance to chemotherapy, sensitivity to anti-angiogenesis therapy and ICIs despite a low mutational burden, and CD8+ T cell infiltration being the predictor for poor prognosis-normally CD8+ T cell infiltration is a good prognostic factor in cancer patients. These "atypical" features have brought researchers to investigate the molecular and immunological mechanisms that lead to the increased T cell infiltrates despite relatively low molecular burdens, as well as to decipher the immune landscape that leads to better response to ICIs. In the present study, we summarize the past and ongoing pivotal clinical trials of immunotherapies for ccRCC, emphasizing the potential molecular and cellular mechanisms that lead to the success or failure of ICI therapy. Single-cell analysis of ccRCC has provided a more thorough and detailed understanding of the tumor immune microenvironment and has facilitated the discovery of molecular biomarkers from the tumor-infiltrating immune cells. We herein will focus on the discussion of some major immune cells, including T cells and tumor-associated macrophages (TAM) in ccRCC. We will further provide some perspectives of using molecular and cellular biomarkers derived from these immune cell types to potentially improve the response rate to ICIs in ccRCC patients.

PANX1 is a potential prognostic biomarker associated with immune infiltration in pancreatic adenocarcinoma: A pan-cancer analysis

Pannexin 1 (PANX1) channel is a critical ATP-releasing pathway that modulates tumor immunity, progression, and prognosis. However, the roles of PANX1 in different cancers remain unclear. We analyzed the expression of PANX1 in human pan-cancer in the Oncomine and GEPIA2.0 databases. The prognostic value of PANX1 expression was determined using Kaplan-Meier plotter and OncoLnc tools. The correlation between PANX1 and tumor-infiltrating immune cells was investigated using the TIMER 2.0. In addition, the relationship between PANX1 and immunomodulators was explored using TISIDB. Finally, gene set enrichment analysis (GSEA) was performed utilizing LinkedOmics. The results indicated that PANX1 was overexpressed in most cancers compared to normal tissues. The high expression of PANX1 was associated with poor prognosis in multiple tumors, especially in pancreatic adenocarcinoma (PAAD). In addition, PANX1 was correlated with a variety of immunomodulators, such as CD274, IL10, CD276, IL2RA, TAP1, and TAP2. PANX1 expression level was significantly related to infiltration of multiple immune cells in many cancers, including cancer associated fibroblast, macrophage, and neutrophil cells. Further analysis revealed that PANX1 was significantly associated with T cells CD8+ (rho = 0.524, P = 1.94e-13) and Myeloid dendritic cell (rho = 0.564, P = 9.45e-16). GSEA results showed that PANX1 was closely associated with leukocyte cell-cell adhesion, endoplasmic reticulum lumen, ECM-receptor interaction, and Focal adhesion pathways in PAAD. PANX1 expression was higher in pan-cancer samples than in normal tissues. The high expression of PANX1 was associated with poor outcome and immune infiltration in multiple cancers, especially in PAAD.

CD177 modulates the function and homeostasis of tumor-infiltrating regulatory T cells

Regulatory T (Treg) cells are one of the major immunosuppressive cell types in cancer and a potential target for immunotherapy, but targeting tumor-infiltrating (TI) Treg cells has been challenging. Here, using single-cell RNA sequencing of immune cells from renal clear cell carcinoma (ccRCC) patients, we identify two distinct transcriptional fates for TI Treg cells, Fate-1 and Fate-2. The Fate-1 signature is associated with a poorer prognosis in ccRCC and several other solid cancers. CD177, a cell surface protein normally expressed on neutrophil, is specifically expressed on Fate-1 TI Treg cells in several solid cancer types, but not on other TI or peripheral Treg cells. Mechanistically, blocking CD177 reduces the suppressive activity of Treg cells in vitro, while Treg-specific deletion of Cd177 leads to decreased tumor growth and reduced TI Treg frequency in mice. Our results thus uncover a functional CD177+ TI Treg population that may serve as a target for TI Treg-specific immunotherapy.

Immunoprofiling: An Encouraging Method for Predictive Factors Examination in Lung Cancer Patients Treated with Immunotherapy

The efficiency of immunotherapy using monoclonal antibodies that inhibit immune checkpoints has been proven in many clinical studies and well documented by numerous registration approaches. To date, PD-L1 expression on tumor and immune cells, tumor mutation burden (TMB), and microsatellite instability (MSI) are the only validated predictive factors used for the qualification of cancer patients for immunotherapy. However, they are not the ideal predictive factors. No response to immunotherapy could be observed in patients with high PD-L1 expression, TMB, or MSI. On the other hand, the effectiveness of this treatment method also may occur in patients without PD-L1 expression or with low TMB and with microsatellite stability. When considering the best predictive factor, we should remember that the effectiveness of immunotherapy relies on an overly complex process depending on many factors. To specifically stimulate lymphocytes, not only should their activity in the tumor microenvironment be unlocked, but above all, they should recognize tumor antigens. The proper functioning of the anticancer immune system requires the proper interaction of many elements of the specific and non-specific responses. For these reasons, a multi-parameter analysis of the immune system at its different activity levels is considered a very future-oriented predictive marker. Such complex immunological analysis is performed using modern molecular biology techniques. Based on the gene expression studies, we can determine the content of individual immune cells within the tumor, its stroma, and beyond. This includes all cell types from active memory cytotoxic T cells, M1 macrophages, to exhausted T cells, regulatory T cells, and M2 macrophages. In this article, we summarize the possibilities of using an immune system analysis to predict immunotherapy efficacy in cancer patients. Moreover, we present the advantages and disadvantages of immunoprofiling as well as a proposed future direction for this new method of immune system analysis in cancer patients who receive immunotherapy.

Transcriptional regulation of VEGFA expression in T-regulatory cells from breast cancer patients

The initiation of new blood vessel formation (neo-angiogenesis) is one of the primary requirements for the establishment of tumor. As the tumor grows beyond a certain size, a hypoxic-condition arises in the inner core of tumor, triggering the release of chemokines, which attract T-regulatory (Treg) cells in the tumor-site. The presence of FOXP3, a lineage-specific transcription factor, expressing Treg cells in various types of tumor implements immunosuppressive and tumor-promoting strategies. One such strategy is the invitation of endothelial cells for neo-vascularization in the tumor site. Here we report that as the disease progresses, Treg cells from breast cancer patients are capable of secreting high-amount of VEGFA. The VEGFA promoter lacks Treg-specific transcription factor FOXP3 binding site. FOXP3 in association with locus-specific transcription factor STAT3 binds to VEGFA promoter to induce its transcription in Treg cells obtained from breast cancer patients. Treg cell-secreted VEGFA induces neo-angiogenesis from endothelial cells under in-vitro conditions. Targeting Tregs in mice with breast tumor reduces tumor growth as well as the level of neo-angiogenesis in the tumor tissue.

Targeting MSS colorectal cancer with immunotherapy: are we turning the corner?

INTRODUCTION

Immunotherapy with checkpoint inhibition has shown potent antitumor activity in patients with microsatellite instability (MSI) metastatic cancer. Microsatellite stable (MSS) colorectal cancer has long been considered resistant to immunotherapy.

AREAS COVERED

In this review, we provide an overview of current progress on strategies to overcome the resistance to immunotherapy in MSS colorectal cancer.

EXPERT OPINION

Emerging evidence suggest that combination of immune modulators such as regorafenib may improve the responsiveness of MSS colorectal cancer to checkpoint blockade. In addition, signs of clinical activity have also been observed in other combination strategies, such as the combination of checkpoint blockade with Stat3 inhibitor, or bispecific T-cell engagers. Nevertheless, predictive biomarkers that can identify patients who may benefit from immunotherapy are key for its implementation in clinical setting. Metastatic disease sites may predict for the response or resistance to checkpoint blockade, with liver metastases emerging as a strong predictive biomarker of lack of benefit from PD-1 targeting, even with combination therapies. Additional efforts are required to study the mechanism of resistance and to develop novel therapeutic strategies to overcome immune resistance.

ABBREVIATIONS

CEA: carcinoembryonic antigen; CR: complete response; CTLA-4: cytotoxic T-lymphocyte-associated protein 4; DCR: disease control rate; MSI-H: microsatellite instability-high; MSS: Microsatellite stable (MSS); OS: overall survival; PD-1: programmed cell death protein 1; PD-L1: programmed death-ligand receptor 1; PR: partial response; PFS: progression-free survival; SD: stable disease; TMB: tumor mutation burden; VEGFR: vascular endothelial growth factor receptor.

Renal cell carcinoma pathology in 2021: 'new need for renal cancer immune profiling'

PURPOSE OF REVIEW

The aim of this review is to outline characteristics of the renal cell carcinoma (RCC) tumor immune microenvironment (TIME), the potential impact of tumor intrinsic alterations on the TIME and the value of metastatic tissue assessment in this context.

RECENT FINDINGS

According to the latest European Association of Urology, European Society for Medical Oncology and National Comprehensive Cancer Network guidelines immune checkpoint inhibition represents a new core treatment strategy in advanced clear cell RCC (ccRCC). Despite its success, the prognosis of many RCC patients remains unsatisfactory most likely because of resistance mechanisms within the TIME. Moreover, most studies assess the primary tumor even though the advanced metastatic disease is targeted. Overall, metastatic RCC has hardly been investigated. First insights into the complexity of the genomic and immune landscape in RCC were recently provided. The functional impact of tumor intrinsic alterations on the TIME has just been described potentially contributing to therapy response in RCC.

SUMMARY

The complexity of the RCC TIME and its potential interdependence with tumor intrinsic alterations has only just been recognized. A deeper understanding of the TIME may reveal predictive and prognostic biomarkers long-awaited in RCC, improve RCC patient stratification and could possibly be most instructive if assessed in metastatic tissue.

Reconnaissance of tumor immune microenvironment spatial heterogeneity in metastatic renal cell carcinoma and correlation with immunotherapy response

A clearer understanding of the tumor immune microenvironment (TIME) in metastatic clear cell renal cell carcinoma (ccRCC) may help to inform precision treatment strategies. We sought to identify clinically meaningful TIME signatures in ccRCC. We studied tumors from 39 patients with metastatic ccRCC using quantitative multiplexed immunofluorescence and relevant immune marker panels. Cell densities were analyzed in three regions of interest (ROIs): tumor core, tumor-stroma interface and stroma. Patients were stratified into low- and high-marker density groups using median values as thresholds. Log-rank and Cox regression analyses while controlling for clinical variables were used to compare survival outcomes to patterns of immune cell distributions. There were significant associations with increased macrophage (CD68⁺ CD163⁺ CD206⁺ ) density and poor outcomes across multiple ROIs in primary and metastatic tumors. In primary tumors, T-bet⁺ T helper type 1 (Th1) cell density was highest at the tumor-stromal interface (P = 0·0021), and increased co-expression of CD3 and T-bet was associated with improved overall survival (P = 0·015) and survival after immunotherapy (P = 0·014). In metastatic tumor samples, decreased forkhead box protein 3 (FoxP3)⁺ T regulatory cell density correlated with improved survival after immunotherapy (P = 0·016). Increased macrophage markers and decreased Th1 T cell markers within the TIME correlated with poor overall survival and treatment outcomes. Immune markers such as FoxP3 showed consistent levels across the TIME, whereas others, such as T-bet, demonstrated significant variance across the distinct ROIs. These findings suggest that TIME profiling outside the tumor core may identify clinically relevant associations for patients with metastatic ccRCC.

Trial watch: Prognostic and predictive value of the immune infiltrate in cancer

Solid tumors are constituted of a variety of cellular components, including bona fide malignant cells as well as endothelial, structural and immune cells. On one hand, the tumor stroma exerts major pro-tumorigenic and immunosuppressive functions, reflecting the capacity of cancer cells to shape the microenvironment to satisfy their own metabolic and immunological needs. On the other hand, there is a component of tumor-infiltrating leucocytes (TILs) that has been specifically recruited in the attempt to control tumor growth. Along with the recognition of the critical role played by the immune system in oncogenesis, tumor progression and response to therapy, increasing attention has been attracted by the potential prognostic and/or predictive role of the immune infiltrate in this setting. Data from large clinical studies demonstrate indeed that a robust infiltration of neoplastic lesions by specific immune cell populations, including (but not limited to) CD8⁺ cytotoxic T lymphocytes, Th1 and Th17 CD4⁺ T cells, natural killer cells, dendritic cells, and M1 macrophages constitutes an independent prognostic indicator in several types of cancer. Conversely, high levels of intratumoral CD4⁺CD25⁺FOXP3⁺ regulatory T cells, Th2 CD4⁺ T cells, myeloid-derived suppressor cells, M2 macrophages and neutrophils have frequently been associated with dismal prognosis. So far, only a few studies have addressed the true predictive potential of TILs in cancer patients, generally comforting the notion that—at least in some clinical settings—the immune infiltrate can reliably predict if a specific patient will respond to therapy or not. In this Trial Watch, we will summarize the results of clinical trials that have evaluated/are evaluating the prognostic and predictive value of the immune infiltrate in the context of solid malignancies.

Clinical Impact of Tumor-Infiltrating Lymphocytes and PD-L1-Positive Cells as Prognostic and Predictive Biomarkers in Urological Malignancies and Retroperitoneal Sarcoma

Simple Summary

Two host-dependent biological characteristics, “avoiding immune destruction” and “tumor-promoting inflammation” have been added to cancer hallmarks in 2011. The interaction and cross-talk among tumor cells and several immune cells in a tumor microenvironment are dynamic and complex processes. The purpose of this review is to discuss the prognostic impact of tumor-infiltrating lymphocytes and predictive biomarkers for immune checkpoint inhibitors in four urological solid tumors, the urothelial carcinoma, renal cell carcinoma, prostate cancer, and retroperitoneal sarcoma, through summarizing the findings of observation studies and clinical trials.

Abstract

Over the past decade, an “immunotherapy tsunami”, more specifically that involving immune checkpoint inhibitors (ICIs), has overtaken the oncological field. The interaction and cross-talk among tumor cells and several immune cells in the tumor microenvironment are dynamic and complex processes. As immune contexture can vary widely across different types of primary tumors and tumor microenvironments, there is still a significant lack of clinically available definitive biomarkers to predict patient response to ICIs, especially in urogenital malignancies. An increasing body of evidence evaluating urological malignancies has proven that tumor-infiltrating lymphocytes (TILs) are a double-edged sword in cancer. There is an urgent need to shed light on the functional heterogeneity in the tumor-infiltrating immune system and to explore its prognostic impact following surgery and other treatments. Notably, we emphasized the difference in the immunological profile among urothelial carcinomas arising from different primary origins, the bladder, renal pelvis, and ureter. Significant differences in the density of FOXP3-positive TILs, CD204-positive tumor-infiltrating macrophages, PD-L1-positive cells, and colony-stimulating factors were observed. This review discusses two topics: (i) the prognostic impact of TILs and (ii) predictive biomarkers for ICIs, to shed light on lymphocyte migration in four solid tumors, the urothelial carcinoma, renal cell carcinoma, prostate cancer, and retroperitoneal sarcoma.

Immune-checkpoint molecules on regulatory T-cells as a potential therapeutic target in head and neck squamous cell cancers

Immune-checkpoint inhibitors improve the survival of head and neck squamous cell carcinoma (HNSCC) patients. Although recent studies have demonstrated that the tumor immune microenvironment (TIME) has critical roles in immunotherapy, the precise mechanisms involved are unclear. Therefore, further investigations of TIME are required for the improvement of immunotherapy. The frequency of effector regulatory T-cells (eTregs) and the expression of immune-checkpoint molecules (ICM) on eTregs and conventional T-cells (Tconvs) both in peripheral blood lymphocytes (PBL) and tumor-infiltrating lymphocytes (TIL) from HNSCC patients were analyzed by flow cytometry and their distributions were evaluated by multi-color immunofluorescence microscopy. High frequency eTreg infiltration into HNSCC tissues was observed and high expressions of CD25, FOXP3, stimulatory-ICM (4-1BB, ICOS, OX40 and GITR) and inhibitory-ICM (programmed cell death-1 [PD-1] and cytotoxic T-lymphocyte-associated protein-4 [CTLA-4]) were found on invasive eTregs. In contrast, the expression of stimulatory-ICM on Tconvs was low and the expression of inhibitory-ICM was high. In addition, ICM-ligands (programmed cell death-1 [PD-L1], galectin-9 and CEACAM-1) were frequently expressed on cancer cells. PD-L1 and galectin-9 were also expressed on macrophages. PD-1⁺ T-cells interacted with PD-L1⁺ cancer cells or PD-L1⁺ macrophages. This suggested that in TIL, eTregs are highly activated, but Tconvs are exhausted or inactivated by eTregs and immune-checkpoint systems, and ICM and eTregs are strongly involved in the creation of an immunosuppressive environment in HNSCC tissues. These suggested eTreg targeting drugs are expected to be a combination partner with immune-checkpoint inhibitors that will improve immunotherapy of HNSCC.

The Tumor Microenvironment: A Milieu Hindering and Obstructing Antitumor Immune Responses

The success of cancer immunotherapy relies on the knowledge of the tumor microenvironment and the immune evasion mechanisms in which the tumor, stroma, and infiltrating immune cells function in a complex network. The potential barriers that profoundly challenge the overall clinical outcome of promising therapies need to be fully identified and counteracted. Although cancer immunotherapy has increasingly been applied, we are far from understanding how to utilize different strategies in the best way and how to combine therapeutic options to optimize clinical benefit. This review intends to give a contemporary and detailed overview of the different roles of immune cells, exosomes, and molecules acting in the tumor microenvironment and how they relate to immune activation and escape. Further, current and novel immunotherapeutic options will be discussed.

Role of Chemokine (C-X-C Motif) Ligand 10 (CXCL10) in Renal Diseases

Chemokine C-X-C ligand 10 (CXCL10), also known as interferon-γ-inducible protein 10 (IP-10), exerts biological function mainly through binding to its specific receptor, CXCR3. Studies have shown that renal resident mesangial cells, renal tubular epithelial cells, podocytes, endothelial cells, and infiltrating inflammatory cells express CXCL10 and CXCR3 under inflammatory conditions. In the last few years, strong experimental and clinical evidence has indicated that CXCL10 is involved in the development of renal diseases through the chemoattraction of inflammatory cells and facilitation of cell growth and angiostatic effects. In addition, CXCL10 has been shown to be a significant biomarker of disease severity, and it can be used as a prognostic indicator for a variety of renal diseases, such as renal allograft dysfunction and lupus nephritis. In this review, we summarize the structures and biological functions of CXCL10 and CXCR3, focusing on the important role of CXCL10 in the pathogenesis of kidney disease, and provide a theoretical basis for CXCL10 as a potential biomarker and therapeutic target in human kidney disease.

Nondestructive, multiplex three-dimensional mapping of immune infiltrates in core needle biopsy

Enumeration of tumor-infiltrating lymphocytes (TILs) in H&E stained tissue sections has demonstrated limited value in predicting immune responses to cancer immunotherapy, likely reflecting the diversity of cell types and immune activation states among tumor infiltrates. Multiparametric flow cytometry enables robust phenotypic and functional analysis to distinguish suppression from activation, but tissue dissociation eliminates spatial context. Multiplex methods for immunohistochemistry (IHC) are emerging, but these interrogate only a single tissue section at a time. Here, we report transparent tissue tomography (T3) as a tool for three-dimensional (3D) imaging cytometry in the complex architecture of the tumor microenvironment, demonstrating multiplexed immunofluorescent analysis in core needle biopsies. Using T3 imaging, image processing and machine learning to map CD3⁺CD8⁺ cytotoxic T cells (CTLs) in whole core needle biopsies from Her2⁺ murine mammary tumors and human head and neck surgical specimens revealed marked inhomogeneity within single needle cores, confirmed by serial section IHC. Applying T3 imaging cytometry, we discovered a strong spatial correlation between CD3⁺CD8⁺ CTLs and microvasculature in the EGFR⁺ parenchyma, revealing significant differences among head and neck cancer patients. These results show that T3 offers simple and rapid access to three-dimensional and quantitative maps of the tumor microenvironment and immune infiltrate, offering a new diagnostic tool for personalized cancer immunotherapy.

A next-generation tumor-targeting IL-2 preferentially promotes tumor-infiltrating CD8+ T-cell response and effective tumor control

While IL-2 can potently activate both NK and T cells, its short in vivo half-life, severe toxicity, and propensity to amplify Treg cells are major barriers that prevent IL-2 from being widely used for cancer therapy. In this study, we construct a recombinant IL-2 immunocytokine comprising a tumor-targeting antibody (Ab) and a super mutant IL-2 (sumIL-2) with decreased CD25 binding and increased CD122 binding. The Ab-sumIL2 significantly enhances antitumor activity through tumor targeting and specific binding to cytotoxic T lymphocytes (CTLs). We also observe that pre-existing CTLs within the tumor are sufficient and essential for sumIL-2 therapy. This next-generation IL-2 can also overcome targeted therapy-associated resistance. In addition, preoperative sumIL-2 treatment extends survival much longer than standard adjuvant therapy. Finally, Ab-sumIL2 overcomes resistance to immune checkpoint blockade through concurrent immunotherapies. Therefore, this next-generation IL-2 reduces toxicity while increasing TILs that potentiate combined cancer therapies.

Interleukin-2 (IL-2) based cancer therapy is limited by severe toxicity and strong Treg amplification at the therapeutic dosage. Here, the authors develop a recombinant IL-2 immunocytokine which is comprised of a tumor-targeting antibody fused to a super mutant IL-2 and show in mouse models that this next-generation IL2 has reduced toxicity and enhanced antitumor activity.

Specific immune cell and lymphatic vessel signatures identified by image analysis in renal cancer

Anti-angiogenic therapy and immune checkpoint inhibition are novel treatment strategies for patients with renal cell carcinoma. Various components and structures of the tumor microenvironment are potential predictive biomarkers and also attractive treatment targets. Macrophages, tumor infiltrating lymphocytes, vascular and lymphatic vessels represent an important part of the tumor immune environment, but their functional phenotypes and relevance for clinical outcome are yet ill defined. We applied Tissue Phenomics methods including image analysis for the standardized quantification of specific components and structures within the tumor microenvironment to profile tissue sections from 56 clear cell renal cell carcinoma patients. A characteristic composition and unique spatial relationship of CD68+ macrophages and tumor infiltrating lymphocytes correlated with overall survival. An inverse relationship was found between vascular (CD34) and lymphatic vessel (LYVE1) density. In addition, outcome was significantly better in patients with high blood vessel density in the tumors, whereas increased lymphatic vessel density in the tumors was associated with worse outcome. The Tissue Phenomics imaging analysis approach allowed visualization and simultaneous quantification of immune environment components, adding novel contextual information, and biological insights with potential applications in treatment response prediction.

Prognostic Value of the Neo-Immunoscore in Renal Cell Carcinoma

Objective: This study evaluated the prognostic value of the newly-built Immunoscore (neo-Immunoscore) in patients with renal cell carcinoma (RCC).

Methods: Eighty-two patients with RCC were enrolled in this study. Their 3- and 5-year survival rates and overall survival (OS) were evaluated. The clinicopathologic data of the 82 patients were collected and analyzed. CD3, CD4, CD8, CD45RO, Foxp3, tumor necrosis factor receptor type II (TNFR2), programmed death ligand-1 (PD-L1), CD68, programmed death-1 (PD-1), cytokeratin (CK), and indoleamine 2,3-dioxygenase (IDO) were separated into two panels and stained using multiplex fluorescent immunohistochemistry methods. An immunologic prediction model of RCC patients, the neo-Immunoscore (neo-IS), was constructed using a Cox regression model. For the prognostic prediction of RCC, the neo-IS with the immunoscore (IS) proposed by the Society for Immunotherapy of Cancer (SITC) were compared by receiver operator characteristic (ROC) curve analysis. Survivals between the neo-IS_low and neo-IS_high groups were analyzed using the Kaplan–Meier method. Multivariate Cox regression survival analysis was applied to analyze independent indicators.

Results: The Cox regression model allowed the establishment of a neo-IS based on three features: CD3CT+, CD4⁺Foxp3⁺CD45ROCT+, and CD8⁺PD-1IM+. Compared to that of the IS proposed by the SITC, the neo-IS obtained a better prediction. The 3- and 5-year survival rates in neo-IS_high RCC patients were significantly higher than those in neo-IS_low RCC patients (94.7 vs. 77.4%, P = 0.035 and 94.7 vs. 64.5%, P = 0.002, respectively). The OS in the neo-IS_low group was significantly shorter than that in the neo-IS_high group (73 vs. 97 months, P = 0.000). In comparisons of the neo-IS with clinical pathological factors, we found that the risk stratification and neo-IS were independent factors for the prognosis of patients with RCC. Moreover, the OS rate of neo-IS_high RCC patients with low- and intermediate- risk was higher than that of neo-IS_low patients.

Conclusion: The newly-constructed IS model more precisely predicted the survival of patients with RCC and may supplement the prognostic value of risk stratification.

Tumor immune microenvironment in non-muscle-invasive urothelial carcinoma of the bladder

Immunotherapy has gained significance in a variety of tumor types including advanced urothelial carcinoma. Noninvasive urothelial lesions have been treated with intravesical Bacillus-Calmette-Guerin (BCG) for decades. Given treatment failure in a subset of these tumors, ongoing clinical trials investigating the role of checkpoint inhibitors are actively pursued in this group of patients. The present study aims to delineate PD-L1, CD8, and FOXP3 expression in tumor microenvironment in non-muscle-invasive urothelial carcinoma samples obtained via sequential biopsies and to assess its potential role in predicting disease outcome. Cases with >1% and> 5% PD-L1 expression in tumor cells showed lower relative risk (RR) to recur at any subsequent biopsy compared with those with lower PD-L1 expression (RRs, 0.83 [P = .009] and 0.81 [P = .03], respectively). Cases with higher expression of FOXP3 in peritumoral lymphocytes were at lower risk for tumor grade progression at any biopsy (RR, 0.2; P = .02). Tumors with FOXP3/CD8 expression ratio of >1 in intratumoral lymphocytes had lower risk of grade progression (RR, 0.28; P = .04). Although higher number of FOXP3-, CD8-, and PD-L1-positive lymphocytes were encountered after BCG treatment, the findings did not reach statistical significance. In patients without BCG treatment, PD-L1 expression in tumor cells and peritumoral lymphocytes varied across serial biopsies, suggesting the need for additional approaches to assess eligibility for immunotherapy in non-muscle-invasive urothelial carcinoma patients.

The role of T helper 17 and regulatory T cells in tumor microenvironment

T helper 17 (Th17) cells were first described as a novel T helper cell lineage independent from Th1 and Th2 subsets. Th17 cells play vital roles in inflammation and tumor immunity. It causes the dissipation of antitumor immunity and contribution to the survival of tumor cells, worsening tumor growth and metastasis. Tumor-infiltrating Th17 cells were seen innumerous cancers in mice and humans. There has been an association between intratumoral Th17 cell infiltration and both good and bad prognoses. Besides the protumoral roles defined for IL-17 andTh17 cells, several reports have shown that Th17 cells also drive antitumoral immunity. Various mechanisms by which Th17 cells control tumor growth are as following: recruitment of several immune cells including DCs, CD4⁺ T cells, and CD8⁺ T cells within tumors, activation of CD8⁺ T cells, and probably plasticity toward Th1 phenotype, related to IFN-γ and TNF-α production. Regulatory T cells (Tregs) have been exhibited to infiltrate human tumors and are believed to restrict antitumor immunity. The effect of Treg cells has been more controversial. Whereas some studies have proposed that a high density of Treg cells within the tumor associated with a poor clinical prognosis, other studies have presented a positive clinical prognosis, underlining the importance of elucidating the clinical significance of Treg cells further. Treg and Th17 cells play both positive and negative roles in regulating antitumor immune responses. In spite of the presence of these cells, yet some tumors develop and grow. These T cells by themselves are not adequate to efficiently mount antitumor immune responses.

Immune context characterization and heterogeneity in primary tumors and pulmonary metastases from renal cell carcinoma

Aim: The knowledge of the immune context of renal cell carcinoma (RCC) is useful to predict benefit from immunotherapy. We retrospectively characterized the immune context of RCC patients underwent primary nephrectomy and pulmonary metastasectomy. Materials & methods: Intratumoral infiltrating lymphocytes and peritumoral renal infiltrating lymphocytes, lymphocyte subpopulations (CD4+, CD8+), PD-1, PD-L1 were explored in paired samples of primary RCC (T) and respective pulmonary metastases (M). Results: The immune variables demonstrated intralesional and intratumoral heterogeneity. Intralesional lymphocyte heterogeneity reached 76% of cases in T, 28% in M. The heterogeneity rate for PD-L1 expression was from 44% (T) to 56% (M); it correlated with better survival. Conclusion: The immune context of RCC is highly variable both within a given tumor and among primary and metastases.

Targeting tumor cells with antibodies enhances anti-tumor immunity

Tumor-targeting antibodies were initially defined as a group of therapeutic monoclonal antibodies (mAb) that recognize tumor-specific membrane proteins, block cell signaling, and induce tumor-killing through Fc-driven innate immune responses. However, in the past decade, ample evidence has shown that tumor-targeting mAb (TTmAb) eradicates tumor cells via activation of cytotoxic T cells (CTLs). In this review, we specifically focus on how TTmAbs induce adaptive anti-tumor immunity and its potential in combination therapy with immune cytokines, checkpoint blockade, radiation, and enzyme-targeted small molecule drugs. Exploring the mechanisms of these preclinical studies and retrospective clinical data will significantly benefit the development of highly efficient and specific TTmAb-oriented anti-tumor remedies.

Distribution and prognostic value of tumor‑infiltrating T cells in breast cancer

Tumor-infiltrating lymphocytes are associated with the response to neoadjuvent chemotherapy and prognosis in breast cancer. However, the distribution, interaction and prognostic value of tumor‑infiltrating T cells, the main component of the tumor microenvironment, have seldom been reported. In the present study, surgical specimens of 72 breast cancer patients were analyzed. Tumor‑infiltrating T cell subsets [cluster of differentiation (CD)4+T, CD8+T and regulatory T cells] and expression of their cytokines [interferon‑γ, interleukin (IL)‑4, and IL‑17] were evaluated by flow cytometry. These parameters together with The Cancer Genome Atlas database were used to demonstrate the distribution, interaction and prognostic value of tumor‑infiltrating T cells in breast cancer. Tumor‑infiltrating lymphocytes were closely associated with histological grade (P=0.03), estrogen receptor status (P=0.006), human epidermal growth factor receptor 2 status (P=0.047) and molecular subtype in breast cancer (P=0.012). The gene expression of CD4, CD8A and forkhead box protein P3 in the tumor was increased compared with healthy breast tissue, and was positively associated with the prognosis of breast cancer patients. HER2+ and triple‑negative breast cancer exhibited a significantly increased percentage of CD4+T cells (P=0.01) and regulatory T cells (P=0.035), and a decreased percentage of CD8+T cells (P=0.006) compared with the luminal subtype. Furthermore, the regulatory T cell number was positively correlated with CD8+T cell number in tumors (R=0.7, P=1.5x10‑162) and significantly inhibited the cytokine secretion of T cells. These results reveal the distribution and interaction of tumor‑infiltrating T cell subsets, and indicate that CD8+T cells and regulatory T cells may be used as reliable predictors of prognosis in breast cancer.

Higher Serum C-reactive Protein Level Represents the Immunosuppressive Tumor Microenvironment in Patients With Clear Cell Renal Cell Carcinoma

INTRODUCTION

C-reactive protein (CRP), a representative inflammatory marker, could serve as a biomarker in renal cell carcinoma because CRP is an important prognostic factor. However, its detailed mechanism remains unknown. This study showed that higher CRP levels correlated with the tumor immune microenvironment, which leads to a worse prognosis. These findings can help to clarify the underlying mechanisms between the presence of systemic inflammatory reaction and prognosis. The aim of this study is to investigate the association between tumor immune microenvironment and CRP in patients with renal cell carcinoma (RCC) to explore the underlying mechanisms between CRP level and prognosis.

PATIENTS AND METHODS

Immunohistochemical measurement of CD4, CD8, CD163 (M2 macrophages), and Foxp3 (Regulatory T [Treg] cells) was performed in patients with clear-cell RCC (n = 111) treated with radical or partial nephrectomy at our institution. The association between immunohistochemical status and preoperative serum CRP level and cancer-specific survival (CSS) was analyzed.

RESULTS

Thirty-three patients (30%) had a high CRP level (≥ 5.0 mg/L), and the CSS rate was significantly worse among these patients than among the remaining patients (P < .001). In patients with strong infiltration of CD8+, Foxp3+, or CD163+ cells, CRP levels were significantly higher (P = .041, P = .001, and P = .035, respectively), and CSS was significantly worse compared with patients with weak infiltration (P = .040, P = .026, and P < .001, respectively). In multivariate analysis, strong CD163+ cells infiltration (P = .001) as well as pathologic T3 (P = .036), lymph-node involvement (P = .007), distant metastasis (P < .001), and Fuhrman nuclear grade 4 (P = .003) were independent prognostic factors for CSS.

CONCLUSIONS

Infiltration of the immunosuppressive cells known as Tregs and M2 macrophages in the tumor microenvironment is associated with higher CRP and poor prognosis in patients with clear-cell RCC. CRP could reflect an immunosuppressive microenvironment.

FOXK2 suppresses the malignant phenotype and induces apoptosis through inhibition of EGFR in clear-cell renal cell carcinoma

Forkhead box K2 (FOXK2) belongs to the forkhead box transcription factor family. Recent studies have revealed that FOXK2 plays essential roles in cancer cell proliferation and survival. However, the biological function of FOXK2 in renal cell carcinoma remains unexplored. In our study, we demonstrated that FOXK2 mRNA and protein levels were decreased in clear-cell renal cell carcinoma (ccRCC) tissues compared to those in corresponding non-tumor renal tissues, and decreased FOXK2 levels were associated with poor prognosis in ccRCC patients after nephrectomy. FOXK2 suppressed proliferation, migration and invasion capabilities of ccRCC cells and induced cellular apoptosis in vitro. Moreover, we found that FOXK2 overexpression inhibited xenograft tumor growth and promoted apoptosis in vivo. Genome-wide transcriptome profiling using FOXK2 overexpressed 769-P cells revealed that the epidermal growth factor receptor (EGFR) was a potential downstream gene of FOXK2. Overexpression of EGFR is able to rescue the inhibited proliferation capacity and the enhanced apoptosis capacity due to the overexpression of FOXK2 in 769-P cells. Collectively, our results indicate that FOXK2 inhibits the malignant phenotype of ccRCC and acts as a tumor suppressor possibly through the inhibition of EGFR.

Elevated expression of IFN-inducible CXCR3 ligands predicts poor prognosis in patients with non-metastatic clear-cell renal cell carcinoma

IFN-inducible CXCR3 ligands (ICL), namely CXCL9, CXCL10 and CXCL11, exhibit pleiotropic roles in orchestrating immunity and angiogenesis. However, the prognosis value of them in renal cell carcinoma (RCC) was still obscure. Thus, we retrospectively used immunohistochemistry approach to evaluate the impact of these ligands on recurrence and survival of non-metastatic clear cell RCC (ccRCC) patients after nephrectomy. We systemically built a prespecified ICL score based on these ligands, and found specimens with high ICL score were prone to possess high Fuhrman grade, necrosis, and high-risk level of SSIGN. Moreover, ICL score stratified patients into different risk subgroups, and remained an independent adverse prognosticator for overall survival (OS) and recurrence-free survival (RFS). Meanwhile, in TCGA database, the increasing ICL mRNA predicted poor survival and early recurrence. Furthermore, after adding ICL score into SSIGN, the C-index for OS and RFS increased from 0.705 to 0.746 and 0.712 to 0.765, respectively. In conclusion, the ICL score based on expression of CXCL9, CXCL10 and CXCL11 stratified non-metastatic ccRCC patients into different risk subgroups of recurrence and death, which might benefit preoperative risk stratification and guide immune therapy in the future.

Immunoprofiling as a predictor of patient's response to cancer therapy-promises and challenges

Immune cell infiltration is common to many tumors and has been recognized by pathologists for more than 100 years. The application of digital imaging and objective assessment software allowed a concise determination of the type and quantity of immune cells and their location relative to the tumor and, in the case of colon cancer, characterized overall survival better than AJCC TNM staging. Subsequently, expression of PD-L1, by 50% or more tumor cells, identified NSCLC patients with double the response rate to anti-PD-1. Soon, automated staining methods will improve reproducibility of multiplex staining and allow for CLIA standards so that multiplex staining can be used to make clinical decisions. Ultimately, machine-learning algorithms will help interpret data from tissue images and lead to improved delivery of precision medicine.

CD8, FoxP3, and CD45RO+ Lymphocytic Infiltrates in Type I and Type II Endometrial Cancers in African American and European American Females

African American (AA) females with endometrial carcinoma have a significantly worse prognosis with regard to disease-free survival and overall survival than their European American (EA) counterparts and this finding is true across all stages and grades. The presence of tumor-infiltrating lymphocytes (TILs) has been demonstrated to be of prognostic significance in a variety of malignancies, including endometrial cancers. This study aims to determine whether clinically significant differences in levels of CD8+ cytotoxic T lymphocytes, FoxP3+ regulatory T lymphocytes, and CD45RO+ memory T lymphocytes exist between races and to document the clinical impact of TILs. One hundred ten patients with endometrial adenocarcinoma, treated with hysterectomy from 2003 to 2011 were studied. Patients were selected to provide equal representation across type and grade for both EAs and AAs. Immunohistochemical stains were used to highlight CD8-positive, FoxP3-positive, and CD45RO-positive TILs at the endometrial-myometrial interface on slides from paraffin-embedded tissue. Patients with "high" or "low" levels of TILs were compared with respect to the race, tumor type, and survival. High levels of CD45RO+ TILs were associated with improved overall survival in EA women (hazard ratio, 0.32; 95% confidence interval, 0.11-0.92; P=0.034). Comparatively, AA women with high levels of CD45RO+ TILs received no survival benefit (hazard ratio, 0.96; 95% confidence interval, 0.35-2.64; P=0.94). High levels of CD8-positive or FoxP3-positive TILs, alone, had no impact on survival. EA patients with TILs containing high levels of CD45RO cells but low levels of CD8+ cells lost the survival benefit; however, limited numbers preclude significant conclusions from this observation. Neither tumor type nor race were predictive of the levels of TILs of any type. Further study with a larger sample size is required to determine the impact of TIL subtype combinations on survival.

Prognostic role of the lymphocyte-to-monocyte ratio in patients undergoing resection for nonmetastatic rectal cancer

Lymphocyte-to-monocyte ratio (LMR) was associated with survival benefit in some types of cancer. The relationship between LMR and rectal cancer has not been investigated. We conducted a retrospective cohort study to assess the prognostic significance of LMR in patients with nonmetastatic rectal cancer. Patients with rectal cancer who underwent potentially curative resection between January 2009 and December 2013 were enrolled. The LMR was calculated from preoperative blood test by dividing the absolute lymphocyte counts by the absolute monocyte counts. The optimal cut-off value for LMR was calculated as the median value. On the basis of the cut-off value, patients were divided into 2 groups: low group and high group. A total of 543 patients with rectal cancer were eligible for this study. The median follow-up time for all patients was 55 months (range 6-85 months). The cut-off value of LMR was 5.13 and patients were divided into 2 groups: low group (LMR < 5.13) and high group (LMR ≥ 5.13). In the univariate and multivariate analysis, the LMR was not significantly associated with overall survival (OS) [hazard ratio (HR): 1.034, 95% confidence intervals (CIs): 0.682-1.566, P = 0.876]. When disease-free survival (DFS) was compared, univariate and multivariate analysis also indicated that the LMR was not significantly associated with DFS (HR: 0.988, 95% CI: 0.671-1.453, P = 0.950). In addition, in the subgroup analysis by tumor-node-metastasis stage, there existed no significance between LMR and OS and DFS. Although as an easy access and highly efficient laboratorial inflammatory marker, LMR cannot predict the prognosis of nonmetastatic rectal cancer patients.

Melittin-MIL-2 fusion protein as a candidate for cancer immunotherapy

BACKGROUND

Cytokine fusion protein that modulates the immune response holds great potential for cancer immunotherapy. IL-2 is an effective treatment against advanced cancers. However, the therapeutic efficacy of IL-2 is limited by severe systemic toxicity. Several mutants recombinant IL-2 can increase antitumor activity and minimize systemic toxicity. Melittin is an attractive anticancer candidate because of its wide-spectrum lytic properties. We previously generated a bifunctional fusion protein melittin-MIL-2, composed of melittin and a mutant IL-2. The melittin-MIL-2 inhibited the growth of human ovarian cancer SKOV3 cells in vitro and in vivo tumor growth. However, whether this antitumor effect could also be used in cancer immunotherapy was unknown. To assess its cancer immunotherapy potential, we further investigated its more effective antitumor immune response and antitumor effect against cancers of different tissue origins in vitro and in vivo.

METHODS

The specific IL-2 activity of the melittin-MIL-2 fusion protein was tested on the cytokine growth dependent cell line CTLL-2. The cytolytic activity was detected by standard 4-h (51)Cr-release assays. PBMC stimulation in response to the melittin-MIL-2 was determined by IFN-γ release assay. We observed the cancer cell proliferation of different tissue origins by MTT assay. The ability of melittin-MIL-2 to inhibit tumor growth in vivo was evaluated by using human liver (SMMC-7721 cancer cells), lung (A549 cancer cells) and ovarian (SKOV3 cancer cells) cancer xenograft models. To assess the immunity within the tumor microenvironment, the level of some cytokines including IFN-γ, TNF-α, IL-12 and IL-4 was analyzed by ELISA. We injected the MDA-MB-231 cells and the melittin-MIL-2 into mice, and the anti-metastatic effect was examined by counting nodules in the lung.

RESULTS

The melittin-MIL-2 was more effective in inducing T cell and NK-cell cytotoxicity. The fusion protein significantly increased IFN-γ production in PBMCs. In vitro, the melittin-MIL-2 mediated immune cells killing or directly killed the cancer cell lines of different tissue origins. In vivo, the fusion protein exhibited stronger inhibition on the growth of transplanted human tumors compared to rIL-2. The melittin-MIL-2 treatment promoted the IFN-γ secretion in tumor tissues and decreased the immunosuppressive cells in vivo. Furthermore, the fusion protein reduced lung metastasis of breast cancer.

CONCLUSIONS

This study provides the evidence that the melittin-MIL-2 can produce stronger immune stimulation and antitumor effects, and the fusion protein is a potent candidate for cancer immunotherapy.

Immune escape to PD-L1/PD-1 blockade: seven steps to success (or failure)

The emergence of programmed death-ligand 1 (PD-L1)/programmed death-1 (PD-1)-targeted therapy has demonstrated the importance of the PD-L1 : PD-1 interaction in inhibiting anticancer T-cell immunity in multiple human cancers, generating durable responses and extended overall survival. However, not all patients treated with PD-L1/PD-1-targeted therapy experience tumor shrinkage, durable responses, or prolonged survival. To extend such benefits to more cancer patients, it is necessary to understand why some patients experience primary or secondary immune escape, in which the immune response is incapable of eradicating all cancer cells. Understanding immune escape from PD-L1/PD-1-targeted therapy will be important to the development of rational immune-combination therapy and predictive diagnostics and to the identification of novel immune targets. Factors that likely relate to immune escape include the lack of strong cancer antigens or epitopes recognized by T cells, minimal activation of cancer-specific T cells, poor infiltration of T cells into tumors, downregulation of the major histocompatibility complex on cancer cells, and immunosuppressive factors and cells in the tumor microenvironment. Precisely identifying and understanding these mechanisms of immune escape in individual cancer patients will allow for personalized cancer immunotherapy, in which monotherapy and combination immunotherapy are chosen based on the presence of specific immune biology. This approach may enable treatment with immunotherapy without inducing immune escape, resulting in a larger proportion of patients obtaining clinical benefit.

The ratio of CD8 to Treg tumor-infiltrating lymphocytes is associated with response to cisplatin-based neoadjuvant chemotherapy in patients with muscle invasive urothelial carcinoma of the bladder

Introduction: Randomized controlled trials of platinum-based neoadjuvant chemotherapy (NAC) for bladder cancer have shown that patients who achieve a pathologic response to NAC exhibit 5 y survival rates of approximately 80–90% while NAC resistant (NR) cases exhibit 5 y survival rates of approximately 30–40%. These findings highlight the need to predict who will benefit from conventional NAC and the need for plausible alternatives. Methods: The pre-treatment biopsy tissues from a cohort of 41 patients with muscle invasive bladder who were treated with NAC were incorporated in tissue microarray and immunohistochemistry for PD-L1, CD8, and FOXP3 was performed. Percentage of PD-L1 positive tumor cells was measured. Tumor-infiltrating lymphocytes (TIL) densities, along with CD8 and Treg-specific TILs, were measured. Results: TIL density was strongly correlated with tumor PD-L1 expression, consistent with the mechanism of adaptive immune resistance in bladder cancer. Tumor cell PD-L1 expression was not a significant predictor of response. Neither was the CD8 nor Treg TIL density associated with response. Intriguingly though, the ratio of CD8 to Treg TIL densities was strongly associated with response (p = 0.0003), supporting the hypothesis that the immune system plays a role in the response of bladder cancer to chemotherapy. Discussion: To our knowledge, this is the first report in bladder cancer showing that the CD8 to Treg TIL density in the pre-treatment tissues is predictive for conventional NAC response. These findings warrant further investigations to both better characterize this association in larger cohorts and begin to elucidate the underlying mechanism(s) of this phenomenon.

Current status of immunotherapy

The successful use of immune checkpoint inhibitors has been big breakthrough in the development of cancer immunotherapy. Anti-CTLA-4 monoclonal antibody, ipilimumab, is the first-approved immune checkpoint inhibitor and has shown durable objective responses for advanced melanoma beyond the effect of dacarbazine. Anti-PD-1 monoclonal antibodies, nivolumab and pembrolizumab, are other immune checkpoint inhibitors that have demonstrated more effective results than conventional drugs in clinical trials for a variety of advanced solid tumors including melanoma, non-small cell lung carcinoma and renal carcinoma. These studies have indicated that the enhancement of anti-cancer immunity by controlling the immune suppressive environment in cancer tissues is an important issue for the development of cancer immune-therapy. Accordingly, in recent years, the enthusiasm for research of cancer immunology has shifted to studies regarding the formation of the immune suppressive environment, immune suppression mechanisms in cancer tissues and the molecules and cells involved in these pathways. Novel findings from these studies might lead to the development of cancer immunotherapy based on control of the immune suppressive environment.

FOXP3+ Tregs: heterogeneous phenotypes and conflicting impacts on survival outcomes in patients with colorectal cancer

The tumor microenvironment composites a mixture of immune lymphoid cells, myeloid cells, stromal cells with complex cytokines, as well as numerous lymphovascular vessels. Colorectal cancer (CRC) is a common malignancy and one of the leading causes of tumor-related death in the United States and worldwide. The immune status in the tumor microenvironment contributes to the survival of a patient with CRC. Regulatory T cells (Tregs) are considered a key factor in immune escape and immunotherapy failure among cancer patients. The transcription factor forkhead box P3 (FOXP3) is a crucial intracellular marker and also a key developmental and functional factor for CD4+CD25+ Tregs. Tregs are correlated with survival in various human neoplasms, and elevated proportions of Tregs are usually associated with unfavorable clinical outcomes. However, the role of Tregs in CRC remains controversial. High densities of tumor-infiltrating Tregs in CRC patients are reported to be correlated with worse or better outcomes. And Tregs may not be predictive of prognosis after resection of the primary tumor. The exact explanations for these discordant results remain unclear. The heterogeneous instincts of cell phenotype, gene expression, and functional activities of Tregs may partly contribute this contrasting result. Furthermore, the lack of a robust marker for identifying Tregs or due to the different techniques applied is also account. The Treg-specific demethylated region (TSDR) was recently reported to be a specific epigenetic marker for natural Tregs (nTregs), which can stably express FOXP3. The FOXP3-TSDR demethylation assay may be an promising technique for CRC-related nTregs studies.

Immunosuppression associated with chronic inflammation in the tumor microenvironment

Chronic inflammation contributes to cancer development via multiple mechanisms. One potential mechanism is that chronic inflammation can generate an immunosuppressive microenvironment that allows advantages for tumor formation and progression. The immunosuppressive environment in certain chronic inflammatory diseases and solid cancers is characterized by accumulation of proinflammatory mediators, infiltration of immune suppressor cells and activation of immune checkpoint pathways in effector T cells. In this review, we highlight recent advances in our understanding of how immunosuppression contributes to cancer and how proinflammatory mediators induce the immunosuppressive microenvironment via induction of immunosuppressive cells and activation of immune checkpoint pathways.

Effect of HIF1α on Foxp3 expression in CD4+ CD25- T lymphocytes

The aim of the present study was to investigate the effect of HIF1α on Foxp3 expression in CD4(+) CD25(-) T lymphocytes. CD4(+) CD25(-) T lymphocytes were sorted from PBMC using a CD4(+) CD25(+) regulatory T cell isolation kit. Lentivirus containing lentiviral vector that overexpressed HIF1α (HIF-lenti) and those containing empty expression vector (control-lenti) were produced. Meanwhile, lentivirus that contained lentiviral vector that suppressed HIF1α expression (siHIF-lenti) and those containing control vector (sicontrol-lenti) were also generated. The sorted CD4(+) CD25(-) T lymphocytes were infected with HIF-lenti, control-lenti, siHIF-lenti, and sicontrol-lenti, respectively. Approximately 72 hr after transduction, real-time PCR and Western blot were carried out to analyze the RNA and protein expression level of HIF1α and Foxp3. CD4(+) CD25(-) T lymphocytes cultured under 21% O2 , 5% CO2 (normoxia) and 1% O2 , 5% CO2 (hypoxia) were used as control. Our results showed that overexpression of HIF1α increased both mRNA and protein expression of Foxp3 and, meanwhile, suppression of HIF1α expression by RNAi could reverse high Foxp3 expression in CD4(+) CD25(-) T lymphocytes caused by hypoxic culture. These results suggested that hypoxia could stimulate Foxp3 expression by increasing HIF1α expression in CD4(+) T lymphocytes which may promote CD4(+) T lymphocytes to convert to Treg.

Efferocytosis creates a tumor microenvironment supportive of tumor survival and metastasis

Programmed cell death, or apoptosis, occurs in nearly all tissues of all multi-cellular organisms. In order to avoid leakage of intracellular contents, which could generate tissue damaging inflammation, apoptotic cells are cleared from tissues by phagocytes, which then dispatch the engulfed dying cell through the lysosomal pathway. Phagocytic clearance of apoptotic cells is referred to as efferocytosis. One key feature of efferocytosis is the production and release of wound healing cytokines by the phagocyte, which acts to resolve inflammation, and promote tissue repair. Phagocytic engulfment of apoptotic cells coupled with cytokine modulation aimed at immune suppression ensures that physiological programmed cell death does not induce inflammation and tissue damage. However, cytokines involved in wound healing and immune suppression are notorious for their role in the tumor microenvironment, increasing tumor cell motility and promoting evasion of anti-tumor immunity. Therefore, current and future studies aimed at targeting important players of efferocytosis should reveal new and efficacious therapeutic approaches for limiting cancer progression and relapse.

The effect of ionizing radiation on regulatory T cells in health and disease

Treg cells are key elements of the immune system which are responsible for the immune suppressive phenotype of cancer patients. Interaction of Treg cells with conventional anticancer therapies might fundamentally influence cancer therapy response rates. Radiotherapy, apart from its direct tumor cell killing potential, has a contradictory effect on the antitumor immune response: it augments certain immune parameters, while it depresses others. Treg cells are intrinsically radioresistant due to reduced apoptosis and increased proliferation, which leads to their systemic and/or intratumoral enrichment. While physiologically Treg suppression is not enhanced by irradiation, this is not the case in a tumorous environment, where Tregs acquire a highly suppressive phenotype, which is further increased by radiotherapy. This is the reason why the interest for combined radiotherapy and immunotherapy approaches focusing on the abrogation of Treg suppression has increased in cancer therapy in the last few years. Here we summarize the basic mechanisms of Treg radiation response both in healthy and cancerous environments and discuss Treg-targeted pre-clinical and clinical immunotherapy approaches used in combination with radiotherapy. Finally, the discrepant findings regarding the predictive value of Tregs in therapy response are also reviewed.