The effect of immune microenvironment on the progression and prognosis of colorectal cancer

Act1 drives chemoresistance via regulation of antioxidant RNA metabolism and redox homeostasis

The IL-17 receptor adaptor molecule Act1, an RNA-binding protein, plays a critical role in IL-17-mediated cancer progression. Here, we report a novel mechanism of how IL-17/Act1 induces chemoresistance by modulating redox homeostasis through epitranscriptomic regulation of antioxidant RNA metabolism. Transcriptome-wide mapping of direct Act1-RNA interactions revealed that Act1 binds to the 5'UTR of antioxidant mRNAs and Wilms' tumor 1-associating protein (WTAP), a key regulator in m6A methyltransferase complex. Strikingly, Act1's binding sites are located in proximity to m6A modification sites, which allows Act1 to promote the recruitment of elF3G for cap-independent translation. Loss of Act1's RNA binding activity or Wtap knockdown abolished IL-17-induced m6A modification and translation of Wtap and antioxidant mRNAs, indicating a feedforward mechanism of the Act1-WTAP loop. We then developed antisense oligonucleotides (Wtap ASO) that specifically disrupt Act1's binding to Wtap mRNA, abolishing IL-17/Act1-WTAP-mediated antioxidant protein production during chemotherapy. Wtap ASO substantially increased the antitumor efficacy of cisplatin, demonstrating a potential therapeutic strategy for chemoresistance.

Immuno-Oncology: New Insights into Targets and Therapies

The role of immunotherapy in the care of surgical oncology patients promises to expand as investigators and clinicians evaluate new targets and approaches. Currently active clinical trials evaluate new immune checkpoints, including lymphocyte activation gene 3, T cell immunoreceptor with Ig and ITIM domains, and killer Ig-like receptor 2DL1/2L3. Vaccines delivered through mRNA have demonstrated exciting results in early clinical trials and hold promise for expanded application. Investigational approaches include dendritic cell vaccines, peptide vaccines, cytokines therapies, and cellular therapies. These studies have the potential to revolutionize the management of surgical oncology patients and promote durable cures following surgical resection.

The Potential Dual Role of H2.0-like Homeobox in the Tumorgenesis and Development of Colorectal Cancer and Its Prognostic Value

Background

H2.0-like homeobox (HLX) is highly expressed in several hematopoietic malignancies. However, the role of HLX in the carcinogenesis and progression of colorectal cancer (CRC) patients has rarely been reported.

Methods

In this study, the data were collected from The Cancer Genome Atlas and Gene Expression Omnibus databases. The diagnostic value of HLX was analyzed by the R package "pROC." The overall survival was estimated using the "survival" and "survminer" packages. A nomogram was established to predict 1-, 3-, and 5-year overall survival of CRC patients. The CIBERSORT software was employed to calculate the relative proportions of 22 immune cells.

Results

HLX expression was downregulated in CRC patients. Remarkably, HLX expression was increased with stage (stage I-stage III) of CRC, and the CRC patients with high HLX expression exhibited a poor prognosis. The promoter methylation level of HLX was prominently increased in CRC samples compared to paracancerous samples. We also found that the six miRNAs target HLX genes, leading to its downregulation, and HLX expression had a negative correlation with its downstream target gene BRI3BP in both CRC and normal samples. Finally, we found that the 12 immune infiltrating cells were observably different between high and low HLX expression groups. The HLX had a significant positive correlation with 8 immune checkpoints (PD-1 (PDCD1), CTLA4, PDL-1 (CD274), PDL-2 (PDCD1LG2), CD80, CD86, LAG3, and TIGIT) expressions.

Conclusion

HLX probably played a carcinostasis role in the early stages of CRC but exhibited a cancer-promoting effect in the advanced stages. Meanwhile, HLX could serve as a reliable prognostic indicator for CRC.

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

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

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

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

Co-expression of PD-1 with TIGIT or PD-1 with TIM-3 on tumor-infiltrating CD8+ T cells showed synergistic effects on improved disease-free survival in treatment-naïve CRC patients

Immune checkpoints (ICs) are highly expressed on tumor-infiltrating immune cells (TIICs) in different malignancies, including colorectal cancer (CRC). T cells play crucial roles in shaping CRC, and their presence in the tumor microenvironment (TME) has proven to be one of the best predictors of clinical outcomes. A crucial component of the immune system is cytotoxic CD8⁺ T cells (CTLs), which play decisive roles in the prognosis of CRC. In this study, we investigated associations of immune checkpoints expressed on tumor-infiltrating CD8⁺ T cells with disease-free survival (DFS) in 45 naïve-treatment CRC patients. First, we examined the associations of single ICs, and found that CRC patients with higher levels of T-cell immunoglobulin and ITIM-domain (TIGIT), T-cell immunoglobulin and mucin domain-3 (TIM-3) and programmed cell death-1 (PD-1) CD8⁺ T cells tended to have longer DFS. Interestingly, when PD-1 expression was combined with other ICs, there were more evident and stronger associations between higher levels of PD-1⁺ with TIGIT⁺ or PD-1⁺ with TIM-3⁺ tumor-infiltrating CD8⁺ T cells and longer DFS. Our findings for TIGIT were validated in The Cancer Genome Atlas (TCGA) CRC dataset. This study is the first to report on the association of co-expression of PD-1 with TIGIT and PD-1 with TIM-3 in CD8⁺ T cells and improved DFS in treatment-naïve CRC patients. This work highlights the significance of immune checkpoint expression on tumor-infiltrating CD8⁺ T cells as critical predictive biomarkers, especially when co-expression of different ICs is considered.

Clinicopathological significance and prognostic role of LAG3 + tumor-infiltrating lymphocytes in colorectal cancer; relationship with sidedness

BACKGROUND

It is well-documented that the interplay between tumor-infiltrating lymphocytes (TILs) and tumor cells is a major determining factor in cancer progression. CD45RO seems to be a reliable indicator for predicting prognosis and disease outcome, along with CD3 and CD8 markers. LAG-3 is another important marker that overexpresses on TILs in a variety of cancers and is associated with disease prognosis; however, its prognostic impact is controversial. Hence, in the present study, we aimed to investigate the presence of CD45RO + , LAG3 + , CD3 + , and CD8 + lymphocytes in CRC tumor tissues and their association with clinicopathological parameters of the disease as well as patients' survival, according to primary tumor locations.

METHODS

Expression of CD45RO, LAG3, CD3, and CD8 was immunohistochemically assessed in tissue sections of 136 patients with CRC. The percentages of TILs expressing these markers were then separately determined in both invasive margin (IM) and center of tumor (CT). Their associations with clinicopathological factors and patients' survival were analyzed in the entire cohort and the subgroups of patients with right- and left- rectum tumors.

RESULTS

Based on our observation, CD45RO + and CD3 + cells were the most frequent infiltrated lymphocytes in both CT and IM regions of colon tumor tissue. Whilst, LAG3 + lymphocytes were the least frequent subset in both areas. Statistical analysis indicated that the frequency of CD45RO + TILs was positively associated with advanced TNM stages (III/IV), in the entire cohort and right-sided tumors (P < 0.05). LAG3 + TILs in IM were also increased in tumor tissues with higher T-stages in the entire cohort (P = 0.027). In univariate analysis, high score of CD45RO + TILs in IM was associated with better overall survival in the entire cohort. High score of CD8 + and CD45RO + lymphocytes in IM were also associated with improved survival in patients with right-sided tumors.

CONCLUSIONS

Our findings generally suggest that the clinicopathological and prognostic significance of immune system-related markers such as CD45RO and LAG3 depends on the primary tumor sides. Our results collectively demonstrated that infiltration of CD45RO + lymphocytes in IM could be an independent prognostic factor in a site-dependent manner.

Immunotherapeutic targets in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is one of the most common types of cancer in the world and has a 5-year survival rate of ~20%. Immunotherapies have shown promising results leading to durable responses, however, they are only effective for a subset of patients. To determine the best therapeutic approach, a thorough and in-depth profiling of the tumour microenvironment (TME) is required. The TME is a complex network of cell types that form an interconnected network, promoting tumour cell initiation, growth and dissemination. The stroma, immune cells and endothelial cells that comprise the TME generate a plethora of cytotoxic or cytoprotective signalling pathways. In this review, we discuss immunotherapeutic targets in NSCLC tumours and how the TME may influence patients' response to immunotherapy.

LAG-3+ tumor-infiltrating lymphocytes ameliorates overall survival in triple-negative breast cancer patients

Purpose

Immune checkpoint molecule lymphocyte-activating gene-3 (LAG-3), which is expressed on active lymphocytes, has proven to be associated with immunosuppression and cancer progression in a variety of solid tumors. However, the role of LAG-3⁺ lymphocytes in human breast cancer (BC) is still not conclusive. We therefore performed a meta-analysis to clarify the role of these cells in prognosis prediction for BC.

Methods

We searched PubMed, Embase, and EBSCO to identify the studies evaluating the association of LAG-3⁺ lymphocyte infiltration and overall survival (OS) and/or disease-free survival (DFS) in BC patients, then combined extracted data with STATA 12.0.

Results

Eight published studies involving 5,859 BC patients were incorporated into this meta-analysis. We noted that a high number of LAG-3⁺ tumor-infiltrating lymphocytes were not appreciably associated with OS and DFS in BC patients. Strikingly, in stratified analyses based on the molecular type of BC, LAG-3⁺ lymphocyte infiltration was remarkably associated with better OS rather than DFS in triple-negative breast cancer (TNBC), whereas it significantly influenced neither OS nor DFS in Her2-positive BC. However, an increased density of these lymphocytes indicated a trend for better OS in Her2-positive BC. In addition, we found that LAG-3⁺ lymphocyte infiltration was also remarkably associated with prolonged OS in Her2-positive BC patients when they were measured by immunohistochemistry (IHC). In addition, an elevated number of these lymphocytes did not correlate with pathological complete response rate or clinicopathological features including lymph node metastasis.

Conclusion

The infiltration of LAG-3⁺ lymphocytes ameliorates OS in TNBC and Her2-positive BC, implicating that it is a valuable prognostic biomarker, and applications of anti-LAG-3 antagonists may possibly be not a promising therapeutic strategy for human BC especially for TNBC.

Immunological and Clinico-Molecular Features of Tumor Border Configuration in Colorectal Cancer

INTRODUCTION

Infiltrating tumor border configuration (ITBC) portends a poor prognosis compared with pushing tumor border configuration (PTBC) in colorectal cancer. The tumor and its surrounding immune microenvironment of tumor border configuration is not well-characterized. We aim to elucidate the differences in expression of molecular markers between the 2 groups using tissue microarray (TMA).

STUDY DESIGN

Immunohistochemistry was performed on TMAs of surgical pathology specimens obtained from colorectal cancer patients consecutively operated at our institution from 2004 to 2015. TMAs were stained for immune cells (CD8, FOXP3, LAG3, PU1, CD163, and PDL1); HLA II, beta 2 microglobulin, and HC10 on tumor cells; BRAFV600E mutation; and DNA mismatch repair proteins (MMR) status. Patients who received neoadjuvant therapy were excluded.

RESULTS

There were 646 tumors with ITBC and 310 tumors with PTBC. There was a significantly lower expression (p < 0.05) of immune components, namely CD8, FOXP3, LAG3, PU1, PDL1 immune cells, and Beta-2 Microglobulin on tumor cells in the tumors with ITBC compared with PTBC, except CD163 immune cells, and HC10 and HLAII on tumor cells. Tumors with ITBC were less likely to be associated with BRAFV600E mutations and deficient MMR proteins (p < 0.001). On analyzing MMR-proficient tumors separately, we could not find any difference in the expression of any molecular marker (including BRAF), except a lower expression of PDL1 immune cells in tumors with ITBC (p < 0.001).

CONCLUSIONS

Colorectal tumors with ITBC are associated with a generalized low immune microenvironment and low rates of BRAFV600E mutation compared with tumors with PTBC. However, the molecular expression of tumor border configuration seems confounded by the MMR molecular signature. MMR-proficient colorectal tumors with ITBC are associated with a lower expression of only PDL1 immune cells among all immune markers examined.

Establishment and validation of a redox-related long non-coding RNAs prognostic signature in head and neck squamous cell carcinoma

Reduction and oxidation (redox) reactions occur in living organisms as part of normal cellular metabolism. Here, we established a novel redox-related long non-coding RNAs (rrlncRNAs) signature to predict the prognosis and therapeutic response in Head and neck squamous cell carcinoma (HNSCC). The expression profile and clinical information were obtained from the TCGA project. In total, 10 differently expressed rrlncRNAs associated with prognosis were identified and involved in a prognostic risk score signature by the least absolute shrinkage and selection operator penalized Cox analysis. The area under the receiver operating characteristic curves of the survival rates predicted by the rrlncRNAs signature over one, two, and three years were found to be 0.651, 0.670, and 0.679. Following the completion of the Kaplan-Meier survival study, we discovered that the lower-risk cohort exhibited a much longer overall survival period in contrast with the higher-risk cohort. Univariate and multivariable Cox regression analyses demonstrated that the risk score independently served as a significant predictive factor. GO annotation and KEGG pathway analyses illustrated that the rrlncRNAs signature was strongly associated with immune-related functions as well as signaling pathways. The tumor-infiltrating immune cells, tumor microenvironment, immune-related functions, HLA gene family expression, immune checkpoint genes expression, and somatic variants differed substantially between the low- and high-risk cohorts. Moreover, patients in low-risk group were predicted to present a favorable immunotherapy responsiveness, while in contrast, the high-risk group patients might have a stronger sensitivity to "docetaxel". According to our findings, the rrlncRNAs signature showed an excellent prognosis predictive value and might indicate therapeutic response to immunotherapy in HNSCC.

Extensive Phenotypic Characterization of T Cells Infiltrating Liver Metastasis from Colorectal Cancer: A Potential Role in Precision Medicine

Colorectal cancer (CRC) is one of the most common cancers worldwide, with liver metastasis being its main cause of death. This study harvested fresh biological material from non-tumor and tumor tissue from 47 patients with CRC liver metastasis after surgery, followed by mechanical cellular extraction and stain-lyse-wash direct immunofluorescence technique. Here, 60 different T-cell populations were characterized by flow cytometry. Tumor samples were also subdivided according to their growth pattern into desmoplastic and non-desmoplastic. When we compared tumor versus non-tumor samples, we observed a significantly lower percentage of T-lymphocyte infiltration in the tumor in which the CD4⁺ T-cell density increased compared to the CD8⁺ T cells. T regulatory cells also increased within the tumor, even with an activated phenotype (HLA-DR⁺). A higher percentage of IL-17-producing cells was present in tumor samples and correlated with the metastasis size. In contrast, we also observed a significant increase in CD8⁺ follicular-like T cells (CD185⁺), suggesting a cytotoxic response to cancer cells. Additionally, most infiltrated T cells exhibit an intermediate activation phenotype (CD25⁺). In conclusion, our results revealed potential new targets and prognostic biomarkers that could take part in an algorithm for personalized medicine approaches improving CRC patients' outcomes.

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

LAG-3 (Lymphocyte activation gene 3) protein is a checkpoint receptor that interacts with LSEC-tin, Galectin-3 and FGL1. This interaction leads to reduced production of IL-2 and IFN-γ. LAG-3 is widely expressed in different tumor types and modulates the tumor microenvironment through immunosuppressive effects. Differential expression in various tumor types influences patient prognosis, which is often associated with coexpression with immune checkpoint inhibitors, such as TIM-3, PD-1 and CTLA-4. Here, we discuss expression profiles in different tumor types. To date, many clinical trials have been conducted using LAG-3 inhibitors, which can be divided into anti-LAG-3 monoclonal antibodies, anti-LAG-3 bispecifics and soluble LAG-3-Ig fusion proteins. LAG-3 inhibitors supress T-cell proliferation and activation by disallowing for the interaction between LAG-3 to MHC-II. The process enhances anti-tumor immune response. In this paper, we will review the current state of knowledge on the structure, function and expression of LAG-3 in various types of cancer, as well as its correlation with overall prognosis, involvement in cell-based therapies and experimental medicine. We will consider the role of compounds targeting LAG-3 in clinical trials both as monotherapy and in combination, which will provide data relating to the efficacy and safety of proposed drug candidates.

Pan-immune-inflammation value is associated with the clinical stage of colorectal cancer

Objective

We investigated the clinical significance of preoperative pan-immune-inflammation value (PIV) in patients with colorectal cancer (CRC).

Methods

In this retrospective study, 366 cases who underwent surgery for CRC were enrolled. Their clinical data were collected. PIV was calculated with the formula PIV = [neutrophil count (109/L)× platelet count (109/L) × monocyte count (109/L) /lymphocyte count (109/L). Patients were divided into high PIV (&gt; median PIV) and low PIV (&lt; median PIV) groups. The relationship between PIV and clinicopathological features of CRC was investigated. Receiver operating characteristic (ROC) curve was plotted to indicate the value of immune-inflammatory biomarkers (IIBs) in predicting the TNM stage of CRC, and the area under the curve (AUC) was calculated to evaluate the actual clinical value of IIBs. AUC &gt; 0.5 and closer to 1 indicated the better predictive efficacy. The influencing factors of PIV in CRC were analyzed.

Results

We found that PIV was positively correlated with tumor size (r = 0.300, p &lt; 0.05), carcinoembryonic antigen (CEA) (r = 0.214, p &lt; 0.05) and carbohydrate antigen 125 (CA-125) (r = 0.249, p &lt; 0.05), but negatively correlated with albumin (Alb) (r = −0.242, p &lt; 0.05). PIV was significantly different in patients with different tumor locations (left or right), surgical methods (laparotomy versus laparoscopic surgery) (p &lt; 0.05), and patients with different pathological T stages, N-stage and TNM stages (p &lt; 0.05). ROC curve analysis of IIBs showed the AUC of PIV was greater than other markers when combined with CEA or carbohydrate antigen 19–9 (CA19–9). Multivariate regression analysis identified T stage, CEA, Alb, and tumor size as the independent influential factors of PIV in CRC.

Conclusion

PIV is associated with the tumor stage in patients with CRC, which may be useful in preoperative assessment of CRC.

Molecular Basis of Extramural Vascular Invasion (EMVI) in Colorectal Carcinoma

BACKGROUND

Extramural vascular invasion (EMVI) is a known poor prognostic factor in colorectal carcinoma; however, its molecular basis has not been defined. This study aimed to assess the expression of molecular markers in EMVI positive colorectal carcinoma to understand their tumor microenvironment.

METHODS

Immunohistochemistry was performed on tissue microarrays of surgically resected colorectal cancer specimens for immunological markers, and BRAFV600E mutation (and on the tissue blocks for mismatch repair proteins). Automated quantification was used for CD8, LAG3, FOXP3, PU1, and CD163, and manual quantification was used for PDL1, HLA I markers (beta-2 microglobulin, HC10), and HLA II. The Wilcoxon rank-sum test was used to compare EMVI positive and negative tumors. A logistic regression model was fitted to assess the predictive effect of biomarkers on EMVI.

RESULTS

There were 340 EMVI positive and 678 EMVI negative chemo naïve tumors. PDL1 was barely expressed on tumor cells (median 0) in the entire cohort. We found a significantly lower expression of CD8, LAG3, FOXP3, PU1 cells, PDL1 positive macrophages, and beta-2 microglobulin on tumor cells in the EMVI positive subset (p ≤ 0.001). There was no association of BRAFV600E or deficient mismatch repair proteins (dMMR) with EMVI. PU1 (OR 0.8, 0.7-0.9) and low PDL1 (OR 1.6, 1.1-2.3) independently predicted EMVI on multivariate logistic regression among all biomarkers examined.

CONCLUSION

There is a generalized blunting of immune response in EMVI positive colorectal carcinoma, which may contribute to a worse prognosis. Tumor-associated macrophages seem to play the most significant role in determining EMVI.

The promising immune checkpoint LAG-3 in cancer immunotherapy: from basic research to clinical application

LAG-3, a type of immune checkpoint receptor protein belonging to the immunoglobulin superfamily, is confirmed to be expressed on activated immune cells, mainly including activated T cells. LAG-3 can negatively regulate the function of T cells, exerting important effects on maintaining the homeostasis of the immune system under normal physiological conditions and promoting tumor cells immune escape in the tumor microenvironment. Given its important biological roles, LAG-3 has been regarded as a promising target for cancer immunotherapy. To date, many LAG-3 inhibitors have been reported, which can be divided into monoclonal antibody, double antibody, and small molecule drug, some of which have entered the clinical research stage. LAG-3 inhibitors can negatively regulate and suppress T cell proliferation and activation through combination with MHC II ligand. Besides, LAG-3 inhibitors can also affect T cell function via binding to Galectin-3 and LSECtin. In addition, LAG-3 inhibitors can prevent the FGL1-LAG-3 interaction, thereby enhancing the human body’s antitumor immune effect. In this review, we will describe the function of LAG-3 and summarize the latest LAG-3 inhibitors in the clinic for cancer therapy.

Analysis of the immune checkpoint lymphocyte activation gene-3 (LAG-3) in endometrial cancer: An emerging target for immunotherapy

BACKGROUND

Lymphocyte activation gene-3 (LAG-3) is a novel molecule that participates in the immune escape of tumor cells and is a target for immunotherapy. However, the expression of LAG-3 in patients with endometrial cancer (EC) has not been comprehensively characterized.

OBJECTIVES

We elucidated the expression of LAG-3 and investigated its correlation with clinicopathological parameters, ProMisE subtypes, CD8⁺ T-cell infiltration and relapse-free survival (RFS) in a retrospective cohort of 421 patients with endometrial cancer.

METHODS

Next-generation sequencing of the polymerase epsilon (POLE) and immunohistochemistry of mismatch repair (MMR)-related protein (MLH1, PMS2, MSH2, and MSH6), p53, CD8 and LAG-3 protein in whole sections were performed.

RESULTS

Positive LAG-3 was detected in tumor cells (TCs) and immune cells (ICs) in 31.6% (133/421) and 24.0% (101/421) of the patients, respectively. LAG-3 positivity in ICs was more common in high-grade, high-intermediate risk, high-risk, and advanced/metastatic subgroups and was relevant to lymphovascular space invasion, while that in TCs was more common in older individuals (≥54 years). LAG-3 expression was more prevalent in POLE ultramutated (POLEmut) and MMR-deficient (MMRd) EC than in p53-abnormal (p53abn) and p53-wild (p53wt) EC in TCs (34.4 % and 66.3% in POLEmut and MMRd versus 28.6% and 19.5% in p53abn and p53wt, P < 0.001) and ICs (78.1 % and 65.1% in POLEmut and MMRd versus 2.9% and 5.2% in p53abn and p53wt, P < 0.001). Positive expression of LAG-3 in TCs and ICs was associated with high levels of tumor-associated CD8⁺ T-cell immune infiltration. Additionally, LAG-3 positivity in TCs was related to improved RFS.

CONCLUSIONS

This study suggests that immunotherapy targeting LAG-3 may play a role in EC patients with POLEmut or MMRd molecular markers. Positive LAG-3 expression in TCs may be a predictor of improved RFS.

Advance of T regulatory cells in tumor microenvironment remodeling and immunotherapy in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive, deadly, and is rarely diagnosed early. Regulatory T cells (Treg) are a multifunctional class of immunosuppressive T cells that help maintain immunologic homeostasis and participate in autoimmune diseases, transplants, and tumors. This cell type mediates immune homeostasis, tolerance, and surveillance and is associated with poor outcomes in PDAC. Tregs remodel the tumor immune microenvironment, mediate tumor immune escape, and promote tumor invasion and metastasis. A promising area of research involves regulating Tregs to reduce their infiltration into tumor tissues. However, the complexity of the immune microenvironment has limited the efficacy of immunotherapy in PDAC. Treg modulation combined with other treatments is emerging. This review summarizes the mechanisms of Tregs activity in tumor immune microenvironments in PDAC and the latest developments in immunotherapy and clinical trials.

IL-17-induced HIF1α drives resistance to anti-PD-L1 via fibroblast-mediated immune exclusion

Increasing evidence suggests that intratumoral inflammation has an outsized influence on antitumor immunity. Here, we report that IL-17, a proinflammatory cytokine widely associated with poor prognosis in solid tumors, drives the therapeutic failure of anti-PD-L1. By timing the deletion of IL-17 signaling specifically in cancer-associated fibroblasts (CAFs) in late-stage tumors, we show that IL-17 signaling drives immune exclusion by activating a collagen deposition program in murine models of cutaneous squamous cell carcinoma (cSCC). Ablation of IL-17 signaling in CAFs increased the infiltration of cytotoxic T cells into the tumor mass and sensitized otherwise resistant cSCC to anti-PD-L1 treatment. Mechanistically, the collagen deposition program in CAFs was driven by IL-17-induced translation of HIF1α, which was mediated by direct binding of Act1, the adaptor protein of IL-17 receptor, to a stem-loop structure in the 3' untranslated region (UTR) in Hif1α mRNA. Disruption of Act1's binding to Hif1α mRNA abolished IL-17-induced collagen deposition and enhanced anti-PD-L1-mediated tumor regression.

Associations of different immune checkpoints-expressing CD4+ Treg/ T cell subsets with disease-free survival in colorectal cancer patients

There are different subsets of T regulatory cells (Tregs), orchestrating critical roles in the regulation of anti-tumor immunity in colorectal cancer (CRC). In this study, we report that a high frequency of circulating CD4⁺FoxP3⁺ Tregs was associated with poorer disease-free survival (DFS), while their higher frequencies in tumor-infiltrating CD4⁺ Tregs was associated with better DFS. We further investigated such associations with four Tregs/T cells expressing or lacking FoxP3 and Helios (FoxP3^±Helios^±). For the first time, we report that a high frequency of circulating CD4⁺FoxP3⁺Helios⁺ Tregs was associated with poorer DFS, while a high frequency of tumor-infiltrating CD4⁺FoxP3⁻Helios⁻ T cells was associated with poorer DFS. In the four FoxP3^±Helios^± T cell subsets expressing any of the immune checkpoints (ICs) investigated, we found that a high frequency of CD4⁺FoxP3⁺Helios⁻PD-1⁺ Tregs in circulation was associated with worse DFS. We also found that high frequencies of FoxP3⁺Helios⁺CTLA-4⁺ Tregs, FoxP3⁺Helios⁻CTLA-4⁺ Tregs, and FoxP3⁻Helios⁺CTLA-4⁺ CD4⁺ T cells in circulation were associated with worse DFS. In contrast, high frequencies of CD4⁺TIM-3⁺ T cells, FoxP3⁺Helios⁺TIM-3⁺ Tregs, and FoxP3⁻Helios⁺TIM-3⁺ CD4⁺ T cells in circulation were associated with longer DFS. Our data show that certain CD4⁺ Treg/T cell subsets could serve as independent predictive biomarkers in CRC patients. Identification of the exact subpopulations contributing to clinical outcomes is critical for prognoses and therapeutic targeting.

Lack of Association Between PDCD-1 Polymorphisms and Colorectal Cancer Risk: A Case-Control Study

Functional variants of immune-related genes may be implicated in the occurrence of colorectal cancer (CRC). In this study, Programmed cell death (PDCD)-1.6 (rs10204525 T/C), PDCD-1.7 (rs7421861 A/G), and PDCD-1.9 (rs2227982 A/G) loci were selected to explore gene expression and the potential susceptibility to the development of CRC. Here, 1,003 CRC patients and 1,303 controls were included and three PDCD-1 tagging loci were selected and analyzed by using SNPscan genotyping assays. SHESIS software was harnessed to obtain the haplotypes of the PDCD-1 gene. We found that the genotype and allele distribution of PDCD-1 tagging loci did not significantly affect the risk of CRC. Adjustment for body mass index, age, smoking, alcohol using and sex also found that PDCD-1 tagging loci did not influence the occurrence of CRC. In conclusion, this study suggests that the PDCD-1 tagging loci (rs10204525, rs7421861, and rs2227982) are not correlated with CRC susceptibility.

Update on lymphocyte-activation gene 3 (LAG-3) in cancers: from biological properties to clinical applications

Immunotherapy that targets checkpoints, especially programmed cell death protein 1 and programmed cell death ligand 1, has revolutionized cancer therapy regimens. The overall response rate to mono-immunotherapy, however, is limited, emphasizing the need to potentiate the efficacy of these regimens. The functions of immune cells are modulated by multiple stimulatory and inhibitory molecules, including lymphocyte activation gene 3 (LAG-3). LAG-3 is co-expressed together with other inhibitory checkpoints and plays key roles in immune suppression. Increasing evidence, particularly in the last 5 years, has shown the potential of LAG-3 blockade in anti-tumor immunity. This review provides an update on the biological properties and clinical applications of LAG-3 in cancers.

Laboratory biomarkers of an effective antitumor immune response. Clinical significance

The modern checkpoint inhibitors block the programmed death-1 receptor and its ligand, cytotoxic T-lymphocyte-associated antigen 4 on tumor cells and lymphocytes, that induces cytotoxic reactions. Nowadays, there are no approved clinical and laboratory predictor markers of immune therapy efficacy, which would allow a more personalized approach to patient selection and treatment. The aim of this review is to analyze possible biomarkers of efficacy for treatment with checkpoint inhibitors according to the pathogenic mechanisms of drug action. The review revealed possible predictive biomarkers, that could be classified to 3 groups: biomarkers of high mutagenic potential of the tumor, biomarkers of high activity of adaptive immunity, biomarkers of low activity of the tumor microenvironment. The determination of the described markers before the start of therapy can be used to formulate a treatment regimen, in which the use of various immunomodulatory drugs, inhibitors of proinflammatory cytokines, angiogenic molecules, and probiotics can be considered.

Intravascular emboli relates to immunosuppressive tumor microenvironment and predicts prognosis in stage III colorectal cancer

BACKGROUND

Stage III colorectal cancer (CRC) patients experience varying degrees of prognosis even if receiving standard therapeutic regimes. Intravascular emboli (IVE), a type of vascular invasion, impacts the clinical outcome in CRC. In this study, we confirmed the role of IVE in predicting the prognosis of stage III CRC patients and characterized the tumor microenvironment (TME) of CRC with IVE.

METHODS

Data from 220 consecutive patients (cohort 1) with stage III CRC undergoing radical surgery was collected retrospectively between January 2009 to December 2014. According to the presence of IVE, which was confirmed by two independent pathologists, patients were classified into two groups. Univariate and multivariate Cox regression analyses were performed to evaluate the relation of IVE presence to patients' prognosis. The association between IVE and clinicopathological factors was also analyzed. Furthermore, differentially expressed genes (DEGs) and gene set enrichment analyses (GSEA) were performed to describe features of the TME based on microarray data consisting of 6 patients. Tumor tissues from a separate cohort of 73 patients with stage III CRC (cohort 2) collected between June 2014 and December 2015 were used to analyze tumor-infiltrating lymphocyte (TIL) by immunohistochemistry (IHC) staining.

RESULTS

IVE was observed in 126 (57.3%) patients and could serve as an unfavorable independent prognostic predictor (P < 0.001) as well as lymph node metastasis (P < 0.05) and tumor location (P < 0.05). Additionally, patients with IVE had a higher neutrophil percentage (P = 0.002) and lower lymphocyte percentage (P = 0.002) relative to those without IVE. CRC with IVE had a significantly different profile of DEGs compared to CRC without IVE, and GSEA showed chronic inflammatory and immunosuppressive TME may promote IVE development. In cohort 2, tumors with IVE had fewer CD3⁺ TILs in the stromal region, as well as fewer CD8⁺ TILs in both stromal and tumoral regions relative to those without IVE.

CONCLUSION

IVE, which was related closely to a chronic inflammatory and immunosuppressive TME, forecasted a worse prognosis of stage III CRC patients and may be taken into consideration when a therapeutic strategy is decided upon.

LAG-3 Expression Predicts Outcome in Stage II Colon Cancer

INTRODUCTION

LAG-3 is an inhibitory immune checkpoint molecule that suppresses T cell activation and inflammatory cytokine secretion. T cell density in the tumor microenvironment of colon cancer plays an important role in the host's immunosurveillance. We therefore hypothesized that LAG-3 expression on tumor-infiltrating lymphocytes (TILs) predicts outcome in patients with stage II colon cancer.

PATIENTS AND METHODS

Immunohistochemical staining for LAG-3 was performed on tissue microarrays (TMAs) of formalin-fixed paraffin-embedded tissue from 142 stage II colon cancer patients. LAG-3 expression was assessed in TILs within both the tumor front and tumor center and scored as either positive or negative. The primary endpoint was disease-free survival (DFS).

RESULTS

In patients diagnosed with stage II colon cancer, the presence of LAG-3 expression on TILs was significantly associated with better 5-year DFS (HR 0.34, 95% CI 0.14-0.80, p = 0.009). The effect on DFS was mainly due to LAG-3-positive TILs in the tumor front (HR 0.33, 95% CI 0.13-0.82, p = 0.012).

CONCLUSION

Assessment of LAG-3 might help to predict outcomes in patients with stage II colon cancer and potentially identify those patients who might benefit from adjuvant chemotherapy. Therefore, LAG-3 may serve as a prognostic biomarker in stage II colon cancer.

Gene of the month: lymphocyte-activation gene 3 (LAG-3)

Lymphocyte-activation gene 3 (LAG-3) is a coreceptor found on activated T-lymphocytes activated B-lymphocytes and natural killer (NK) cells. It is closely related to CD4 where it shares multiple common and divergent features. It contains specific binding sites with high affinity to major histocompatibility complex (MHC) Class II and functions as an inhibitor of T-cell signalling. Tumour-infiltrating lymphocytes with high LAG-3 expression have been found in many solid tumours including ovarian cancer, melanoma, colorectal cancer and haematological malignancies including Hodgkin and diffuse large B-cell lymphoma. LAG-3 antagonism has been demonstrated to restore the anti-tumourigenic function of T-cells in vivo, however, mechanistic knowledge remains relatively poorly defined. As other immune checkpoint inhibitors have transformed the management of difficult to treat cancers, such as melanoma, it is hoped that LAG-3 might have the same potential. This review will explore LAG-3 modulation as an anticancer therapy, highlighting recent clinical developments.

Immunotherapy in colorectal cancer

The immune tumor microenvironment (TME) of colorectal cancer (CRC) is a crucial contributor to disease biology, making it an important target for therapeutic intervention. The diversity of immune cell populations within various subsets of CRC has led to the discovery that immune characterization of the TME has both prognostic and predictive value for patients. The convergence of improved molecular and cellular characterization of CRC along with the widespread use of immunotherapy in solid tumors has led to a revolution in the approach to clinical care. Monoclonal antibodies (mAbs) which target key immune checkpoints, such as programmed death-1 (PD-1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4), have demonstrated remarkable clinical activity in microsatellite instability-high (MSI-H) CRCs and are now used in routine practice. The observation that MSI-H cancers are highly infiltrated with immune cells and carry a high neoantigen load led to the successful targeting of these cancers with immunotherapy. More recently, the Food and Drug Administration (FDA) approved a PD-1 inhibitor for microsatellite stable (MSS) cancers with high tumor mutation burden. However, the anti-tumor activity of immunotherapy is rare in the majority of CRC. While immune cell characterization does provide prognostic value in these patients, these observations have not yet led to therapeutic interventions. By delineating factors that predict efficacy, resistance, and therapeutic targets, ongoing research will inform the development of effective combination strategies for the vast majority of MSS CRC and immunotherapy-resistant MSI-H cancers.

Understanding LAG-3 Signaling

Lymphocyte activation gene 3 (LAG-3) is a cell surface inhibitory receptor with multiple biological activities over T cell activation and effector functions. LAG-3 plays a regulatory role in immunity and emerged some time ago as an inhibitory immune checkpoint molecule comparable to PD-1 and CTLA-4 and a potential target for enhancing anti-cancer immune responses. LAG-3 is the third inhibitory receptor to be exploited in human anti-cancer immunotherapies, and it is considered a potential next-generation cancer immunotherapy target in human therapy, right next to PD-1 and CTLA-4. Unlike PD-1 and CTLA-4, the exact mechanisms of action of LAG-3 and its relationship with other immune checkpoint molecules remain poorly understood. This is partly caused by the presence of non-conventional signaling motifs in its intracellular domain that are different from other conventional immunoregulatory signaling motifs but with similar inhibitory activities. Here we summarize the current understanding of LAG-3 signaling and its role in LAG-3 functions, from its mechanisms of action to clinical applications.

MicroRNA-Based Therapeutics for Drug-Resistant Colorectal Cancer

Although therapeutic approaches for patients with colorectal cancer (CRC) have improved in the past decades, the problem of drug resistance still persists and acts as a major obstacle for effective therapy. Many studies have shown that drug resistance is related to reduced drug uptake, modification of drug targets, and/or transformation of cell cycle checkpoints. A growing body of evidence indicates that several microRNAs (miRNAs) may contribute to the drug resistance to chemotherapy, targeted therapy, and immunotherapy by regulating the drug resistance-related target genes in CRC. These drug resistance-related miRNAs may be used as promising biomarkers for predicting drug response or as potential therapeutic targets for treating patients with CRC. In this review, we summarized the recent discoveries regarding anti-cancer drug-related miRNAs and their molecular mechanisms in CRC. Furthermore, we discussed the challenges associated with the clinical application of miRNAs as biomarkers for the diagnosis of drug-resistant patients and as therapeutic targets for CRC treatment.

Understanding and Targeting Human Cancer Regulatory T Cells to Improve Therapy

Regulatory T cells (Tregs) are critical in maintaining immune homeostasis under various pathophysiological conditions. A growing body of evidence demonstrates that Tregs play an important role in cancer progression and that they do so by suppressing cancer-directed immune responses. Tregs have been targeted for destruction by exploiting antibodies against and small-molecule inhibitors of several molecules that are highly expressed in Tregs-including immune checkpoint molecules, chemokine receptors, and metabolites. To date, these strategies have had only limited antitumor efficacy, yet they have also created significant risk of autoimmunity because most of them do not differentiate Tregs in tumors from those in normal tissues. Currently, immune checkpoint inhibitor (ICI)-based cancer immunotherapies have revolutionized cancer treatment, but the resistance to ICI is common and the elevation of Tregs is one of the most important mechanisms. Therapeutic strategies that can selectively eliminate Tregs in the tumor (i.e. therapies that do not run the risk of causing autoimmunity by affecting normal tissue), are urgently needed for the development of cancer immunotherapies. This chapter discusses specific properties of human Tregs under the context of cancer and the various ways to target Treg for cancer immunotherapy.

Intestinal Regulatory T Cells

Mucosal surfaces are distinctive sites exposed to environmental, dietary, and microbial antigens. Particularly in the gut, the host continuously actively adapts via complex interactions between the microbiota and dietary compounds and immune and other tissue cells. Regulatory T cells (Tregs) are critical for tuning the intestinal immune response to self- and non-self-antigens in the intestine. Its importance in intestinal homeostasis is illustrated by the onset of overt inflammation caused by deficiency in Treg generation, function, or stability in the gut. A substantial imbalance in Tregs has been observed in intestinal tissue during pathogenic conditions, when a tightly regulated and equilibrated system becomes dysregulated and leads to unimpeded and chronic immune responses. In this chapter, we compile and critically discuss the current knowledge on the key factors that promote Treg-mediated tolerance in the gut, such as those involved in intestinal Treg differentiation, specificity and suppressive function, and their immunophenotype during health and disease. We also discuss the current state of knowledge on Treg dysregulation in human intestine during pathological states such as inflammatory bowel disease (IBD), necrotizing enterocolitis (NEC), graft-versus-host disease (GVHD), and colorectal cancer (CRC), and how that knowledge is guiding development of Treg-targeted therapies to treat or prevent intestinal disorders.

Genetic Variants in the Regulatory T cell-Related Pathway and Colorectal Cancer Prognosis

BACKGROUND

High numbers of lymphocytes in tumor tissue, including T regulatory cells (Treg), have been associated with better colorectal cancer survival. Tregs, a subset of CD4+ T lymphocytes, are mediators of immunosuppression in cancer, and therefore variants in genes related to Treg differentiation and function could be associated with colorectal cancer prognosis.

METHODS

In a prospective German cohort of 3,593 colorectal cancer patients, we assessed the association of 771 single-nucleotide polymorphisms (SNP) in 58 Treg-related genes with overall and colorectal cancer-specific survival using Cox regression models. Effect modification by microsatellite instability (MSI) status was also investigated because tumors with MSI show greater lymphocytic infiltration and have been associated with better prognosis. Replication of significant results was attempted in 2,047 colorectal cancer patients of the International Survival Analysis in Colorectal Cancer Consortium (ISACC).

RESULTS

A significant association of the TGFBR3 SNP rs7524066 with more favorable colorectal cancer-specific survival [hazard ratio (HR) per minor allele: 0.83; 95% confidence interval (CI), 0.74-0.94; P value: 0.0033] was replicated in ISACC (HR: 0.82; 95% CI, 0.68-0.98; P value: 0.03). Suggestive evidence for association was found with two IL7 SNPs, rs16906568 and rs7845577. Thirteen SNPs with differential associations with overall survival according to MSI in the discovery analysis were not confirmed.

CONCLUSIONS

Common genetic variation in the Treg pathway implicating genes such as TGFBR3 and IL7 was shown to be associated with prognosis of colorectal cancer patients.

IMPACT

The implicated genes warrant further investigation.

T-cell-based immunotherapy in colorectal cancer

Colorectal cancer (CRC) is the leading cause of cancer death worldwide. CRC therapeutic strategies include surgical resection, chemotherapy, radiotherapy, and other approaches. However, patients with metastatic CRC have worse prognoses. In recent years, T-cell-based immunotherapy has elicited promising responses in B-cell malignancies, melanoma, and lung cancer, but most CRC patients are resistant to immunotherapy, chemotherapy, and targeted therapy. Immune checkpoint inhibitors have shown encouraging results in non-small cell lung cancer, melanoma, and other cancers, but immune checkpoint blockade is only effective for CRC subset with microsatellite instability. Other immunotherapies, such as cytokines, cancer vaccines, small molecules, oncolytic viruses, and chimeric antigen-receptor therapy, are currently in use against CRC. This review analyzes recent developments in immunotherapy for CRC treatment as well as the challenges in overcoming resistance.

Tre2-Bub2-Cdc16 Family Proteins Based Nomogram Serve as a Promising Prognosis Predicting Model for Melanoma

Tre2-Bub2-Cdc16 (TBC) proteins are conserved in eukaryotic organisms and function as negative feedback dominating the GAPs for Rab GTPases, while the function of TBC proteins in melanoma remains unclear. In this study, we observed the differential expression of 33 TBC genes in TCGA datasets classified by clinical features. Seven prognostic-associated TBC genes were identified by LASSO Cox regression analysis. Mutation analysis revealed distinctive frequency alteration in the seven prognostic-associated TBCs between cases with high and low scores. High-risk score and cluster 1 based on LASSO Cox regression and consensus clustering analysis were relevant to clinical features and unfavorable prognosis. GSVA analysis showed that prognostic-associated TBCs were related to metabolism and protein transport signaling pathway. Correlation analysis indicated the relationship between the prognostic-associated TBCs with RAB family members, invasion-related genes and immune cells. The prognostic nomogram model was well established to predict survival in melanoma. What's more, interference of one of the seven TBC proteins TBC1D7 was confirmed to inhibit the proliferation, migration and invasion of melanoma cells in vitro. In summary, we preliminarily investigated the impact of TBCs on melanoma through multiple bioinformatics analysis and experimental validation, which is helpful for clarifying the mechanism of melanoma and the development of anti-tumor drugs.

Targeting the immune milieu in gastrointestinal cancers

Gastrointestinal (GI) cancers are among the most common and lethal solid tumors worldwide. Unlike in malignancies such as lung, renal and skin cancers, the activity of immunotherapeutic agents in GI cancers has, on the whole, been much less remarkable and do not apply to the majority. Furthermore, while incremental progress has been made and approvals for use of immune checkpoint inhibitors (ICIs) in specific subsets of patients with GI cancers are coming through, in a population of 'all-comers', it is frequently unclear as to who may benefit most due to the relative lack of reliable predictive biomarkers. For most patients with newly diagnosed advanced or metastatic GI cancer, the mainstay of treatment still involves chemotherapy and/or a targeted agent however, beyond the second-line this paradigm confers minimal patient benefit. Thus, current research efforts are concentrating on broadening the applicability of ICIs in GI cancers by combining them with agents designed to beneficially remodel the tumor microenvironment (TME) for more effective anti-cancer immunity with intention of improving patient outcomes. This review will discuss the currently approved ICIs available for the treatment of GI cancers, the strategies underway focusing on combining ICIs with agents that target the TME and touch on recent progress toward identification of predictors of sensitivity to immune checkpoint blockade in GI cancers.

LAG-3: from molecular functions to clinical applications

To prevent the destruction of tissues owing to excessive and/or inappropriate immune responses, immune cells are under strict check by various regulatory mechanisms at multiple points. Inhibitory coreceptors, including programmed cell death 1 (PD-1) and cytotoxic T lymphocyte antigen 4 (CTLA-4), serve as critical checkpoints in restricting immune responses against self-tissues and tumor cells. Immune checkpoint inhibitors that block PD-1 and CTLA-4 pathways significantly improved the outcomes of patients with diverse cancer types and have revolutionized cancer treatment. However, response rates to such therapies are rather limited, and immune-related adverse events are also observed in a substantial patient population, leading to the urgent need for novel therapeutics with higher efficacy and lower toxicity. In addition to PD-1 and CTLA-4, a variety of stimulatory and inhibitory coreceptors are involved in the regulation of T cell activation. Such coreceptors are listed as potential drug targets, and the competition to develop novel immunotherapies targeting these coreceptors has been very fierce. Among such coreceptors, lymphocyte activation gene-3 (LAG-3) is expected as the foremost target next to PD-1 in the development of cancer therapy, and multiple clinical trials testing the efficacy of LAG-3-targeted therapy are underway. LAG-3 is a type I transmembrane protein with structural similarities to CD4. Accumulating evidence indicates that LAG-3 is an inhibitory coreceptor and plays pivotal roles in autoimmunity, tumor immunity, and anti-infection immunity. In this review, we summarize the current understanding of LAG-3, ranging from its discovery to clinical application.

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.

News on immune checkpoint inhibitors as immunotherapy strategies in adult and pediatric solid tumors

Immune checkpoint inhibitors (ICIs) have shown unprecedented benefits in various adult cancers, and this success has prompted the exploration of ICI therapy even in childhood malignances. Although the use of ICIs as individual agents has achieved disappointing response rates, combinational therapies are likely to promise better results. However, only a subset of patients experienced prolonged clinical effects, thus suggesting the need to identify robust bio-markers that predict individual clinical response or resistance to ICI therapy as the main challenge. In this review, we focus on how the use of ICIs in adult cancers can be translated into pediatric malignances. We discuss the physiological mechanism of action of each IC, including PD-1, PD-L1 and CTLA-4 and the new emerging ones, LAG-3, TIM-3, TIGIT, B7-H3, BTLA and IDO-1, and evaluate their prognostic value in both adult and childhood tumors. Furthermore, we offer an overview of preclinical models and clinical trials currently under investigation to improve the effectiveness of cancer immunotherapies in these patients. Finally, we outline the main predictive factors that influence the efficacy of ICIs, in order to lay the basis for the development of a pan-cancer immunogenomic model, able to direct young patients towards more specific immunotherapy.

High levels of tumor-infiltrating lymphocytes showed better clinical outcomes in FOLFOX-treated gastric cancer patients

Background: Tumor-infiltrating lymphocytes (TILs) and postoperative chemotherapeutics interact in the tumor micro-environment. This interaction has not been well investigated in gastric cancer. Materials & methods: A total of 129 patients were divided into high or low TILs based on the median number of positive CD3⁺ and FoxP3⁺ T cells, which was assessed by immunocytochemistry. Results: Cox regression analysis showed that the stage III disease with shorter overall survival was significant. The analysis showed that high numbers of CD3⁺ or FoxP3⁺ T cells have better clinical outcomes in FOLFOX-treated patients. Conclusion: High CD3⁺ and FoxP3⁺ T-cell infiltration was associated with better clinical outcomes in patients with gastric cancer treated with FOLFOX, suggesting TILs incorporated into algorithms to improve the therapeutic efficacy of optimal chemotherapy.

Lymphocyte activation gene-3 (LAG3) mRNA and protein expression on tumour infiltrating lymphocytes (TILs) in oesophageal adenocarcinoma

PURPOSE

Lymphocyte activation gene-3 (LAG3) is an immunosuppressive checkpoint molecule expressed on T cells. The frequency and distribution of LAG3 expression in oesophageal adenocarcinoma (EAC) is unknown. Aim of the study was the evaluation and distribution of LAG3 on tumour infiltrating lymphocytes (TILs) and correlation with clinico-pathological and molecular data.

METHODS

We analysed tumor tissue samples using immunohistochemistry, multi-colour immunofluorescence and mRNA in-situ technology. The analyses were performed on a multi-spot tissue microarray (TMA) with 165 samples, followed by an evaluation on a single-spot TMA with 477 samples. These results were correlated with clinical and molecular tumour data.

RESULTS

LAG3 expression on TILs was detectable in 10.5% on the multi-spot TMA and 11.4% on the single-spot TMA. There was a strong correlation between protein expression and mRNA expression (p < 0.001) in TILs. LAG 3 expression was correlated with CD4+ and CD8+ T-cells within the tumor (p < 0.001). LAG3 expression showed an improved overall survival (OS) compared to patients without LAG3 expression (median OS 70.2 vs. 26.9 months; p = 0.046). The effect was even clearer in the group of patients with tumour stages > pT2 (70.2 vs 25.0 months; p = 0.037).

CONCLUSION

This is the first description of LAG3 expression on TILs in EAC, underscoring the importance of immunomodulation in EAC. Our data suggest an impact of LAG3 in a relevant subset of EAC. Therapeutic studies investigating the efficacy of LAG3 inhibition in EAC will also provide predictive evidence and relevance of the immunohistochemical determination of LAG3 expression.

LAG3 (CD223) and autoimmunity: Emerging evidence

Immune checkpoint molecules play pivotal roles in maintaining the immune homeostasis. Targeting these molecules, such as the classical Cytotoxic T-Lymphocyte Antigen 4 (CTLA4) and Programmed Cell Death Protein 1 (PD1), achieves great success in treating cancers. However, not all the patients respond well. This urges the immunologists to identify novel immune checkpoint molecules. Lymphocyte activation gene-3 (LAG3; CD223) is a newly identified inhibitory receptor. It is expressed on a variety of immune cells, including CD4⁺ T cells, CD8⁺ T cells, Tregs, B cells, and NK cells. Its unique intracellular domains, signaling patterns as well as the striking synergy observed in its targeted therapy with anti-PD1 indicate the important role of LAG3 in maintaining immune tolerance. Currently, a variety of agents targeting LAG3 are in clinical trials, revealing great perspectives in the future immunotherapy. In this review, we briefly summarize the studies on LAG3, including its structure, isoforms, ligands, signaling, function, roles in multiple diseases, as well as the latest targeted therapeutic advances, with particular concern on the potential association of LAG3 with autoimmune diseases.

Targeting immune checkpoints: Building better therapeutic puzzle in pancreatic cancer combination therapy

Pancreatic cancer is related to a very weak diagnosis; the close parallel between disease incidence and mortality rates from pancreatic cancer reflects the fatal nature of this disease. Although early detection procedures are growing, they are not applicable yet for pancreatic cancer. The majority of cancer patients suffer from advanced disease, in which surgery has no potential effect. Based on the growing evidence, it is predicated that cancer immunotherapy alone or in combination will probably be an essential section of different cancer treatment methods. There are different kinds of immune processes, including various antitumour and tumour-promoting leukocytes. Moreover, tumour cells utilise numerous approaches to overwhelm the immune response. Use of antibody in the therapeutic protocols is proving significant success and is probably a key element of cancer treatment. This method is directed against numerous negative immunologic regulators and immune checkpoints. In the present review, the clinical outlines of immune checkpoint inhibition are discussed in pancreatic cancer.

Lymphocyte-activation gene 3 (LAG3): The next immune checkpoint receptor

Immune checkpoint therapy has revolutionized cancer treatment by blocking inhibitory pathways in T cells that limits the an effective anti-tumor immune response. Therapeutics targeting CTLA-4 and PD1/PDL1 have progressed to first line therapy in multiple tumor types with some patients exhibiting tumor regression or remission. However, the majority of patients do not benefit from checkpoint therapy emphasizing the need for alternative therapeutic options. Lymphocyte Activation Gene 3 (LAG3) or CD223 is expressed on multiple cell types including CD4⁺ and CD8⁺ T cells, and T_regs, and is required for optimal T cell regulation and homeostasis. Persistent antigen-stimulation in cancer or chronic infection leads to chronic LAG3 expression, promoting T cell exhaustion. Targeting LAG3 along with PD1 facilitates T cell reinvigoration. A substantial amount of pre-clinical data and mechanistic analysis has led to LAG3 being the third checkpoint to be targeted in the clinic with nearly a dozen therapeutics under investigation. In this review, we will discuss the structure, function and role of LAG3 in murine and human models of disease, including autoimmune and inflammatory diseases, chronic viral and parasitic infections, and cancer, emphasizing new advances in the development of LAG3-targeting immunotherapies for cancer that are currently in clinical trials.

Lymphocyte activation gene 3 (LAG3) protein expression on tumor-infiltrating lymphocytes in aggressive and TP53-mutated salivary gland carcinomas

Salivary gland carcinomas (SGCs) are rare and can be subdivided into distinct entities, some of which confer a poor prognosis. As targets for effective systemic therapy are warranted, some studies investigated the role of immune-checkpoint proteins PD-L1 and CTLA-4 in SGC. Our study depicts the expression of lymphocyte activation gene 3 (LAG3) in a test cohort and a larger validation cohort, totaling 139 SGCs. LAG3 is expressed on tumor-infiltrating lymphocytes (TILs), mediates T cell exhaustion and is subject to numerous currently recruiting clinical studies. Overall, one-third of SGCs were infiltrated by LAG3-expressing TILs with a strikingly high concordance between the test cohort and the validation cohort (30% and 28.2%, respectively). In the validation cohort, entity-wise LAG3 expression frequencies were highly variable. The highest rates were observed in salivary duct carcinoma (SDC; 66.7%) and adenocarcinoma not otherwise specified (ANOS; 50.0%). We observed LAG3 expression on effector T cells and in smaller frequencies also on FOXP3− T helper cells and FOXP3+ Tregs. LAG3 expression significantly correlated with advanced nodal metastases, cytotoxic T cell infiltrate and TP53 mutations. In the group of adenoid cystic carcinomas, LAG3 expression was also associated with a shorter event-free survival (EFS). Tumors with TP53 nonsense mutations (TP53 null type) exhibited higher LAG3 frequencies and a shorter EFS compared to TP53 wild type. This is the first report of LAG3 expression in SGC, a promising target for immunotherapy. LAG3 blockage could be distinctly applicable for SDC and ANOS, two SGC types with a particularly poor outcome.

IL-17-Producing Cells in Tumor Immunity: Friends or Foes?

IL-17 is produced by RAR-related orphan receptor gamma t (RORγt)-expressing cells including Th17 cells, subsets of γδT cells and innate lymphoid cells (ILCs). The biological significance of IL-17-producing cells is well-studied in contexts of inflammation, autoimmunity and host defense against infection. While most of available studies in tumor immunity mainly focused on the role of T-bet-expressing cells, including cytotoxic CD8⁺ T cells and NK cells, and their exhaustion status, the role of IL-17-producing cells remains poorly understood. While IL-17-producing T-cells were shown to be anti-tumorigenic in adoptive T-cell therapy settings, mice deficient in type 17 genes suggest a protumorigenic potential of IL-17-producing cells. This review discusses the features of IL-17-producing cells, of both lymphocytic and myeloid origins, as well as their suggested pro- and/or anti-tumorigenic functions in an organ-dependent context. Potential therapeutic approaches targeting these cells in the tumor microenvironment will also be discussed.

PD-1/PD-L1-dependent immune response in colorectal cancer

Colorectal cancer (CRC) is still considered as the third most frequent cancer in the world. Microsatellite instability (MSI), inflammation, and microRNAs have been demonstrated as the main contributing factors in CRC. Subtype 1 CRC is defined by NK cells infiltration, induction of Th1 lymphocyte and cytotoxic T cell responses as well as upregulation of immune checkpoint proteins including programmed cell death-1 (PD-1). Based on the diverse features of CRC, such as the stage and localization of the tumor, several treatment approaches are available. However, the efficiency of these treatments may be decreased due to the development of diverse resistance mechanisms. It has been proven that monoclonal antibodies (mAbs) can increase the effectiveness of CRC treatments. Nowadays, several mAbs including nivolumab and pembrolizumab have been approved for the treatment of CRC. Immune checkpoint receptors including PD-1 can be inhibited by these antibodies. Combination therapy gives an opportunity for advanced treatment for CRC patients. In this review, an update has been provided on the molecular mechanisms involved in MSI colorectal cancer immune microenvironment by focusing on PD-ligand 1 (PD-L1) and treatment of patients with advanced immunotherapy, which were examined in the different clinical trial phases. Considering induced expression of PD-L1 by conventional chemotherapeutics, we have summarized the role of PD-L1 in CRC, the chemotherapy effects on the PD-1/PD-L1 axis and novel combined approaches to enhance immunotherapy of CRC by focusing on PD-L1.

The local inflammatory response in colorectal cancer - Type, location or density? A systematic review and meta-analysis

INTRODUCTION

The host anti-tumour inflammatory response is a strong prognostic indicator, and tumour infiltrating lymphocytes (TILs) are believed to have a complimentary role alongside TNM assessment in dictating future management. However, there is wide disagreement regarding the most efficacious and cost-effective method of assessment.

METHODS

A comprehensive literature search was performed of EMBASE, MedLine and PubMed as well as an assessment of references to identify all relevant studies relating to the assessment of the peri-tumoural inflammatory response or TILs and prognosis in colorectal cancer (CRC). A meta-analysis was performed of 67 studies meeting the REMARK criteria using RevMan software.

RESULTS

Intratumoural assessment of both CD3 and CD8 in CRC were significant for disease-free survival (DFS) (combined HRs 0.46; 95%CI: 0.39-0.54 and 0.54; 95%CI: 0.45-0.65), as well as overall survival (OS) and disease-specific survival (DSS). The same was true for assessment of CD3 and CD8 at the invasive margin (DFS: combined HRs 0.45; 95%CI: 0.33-0.61 and 0.51; 95%CI: 0.41-0.62). However, similar fixed effects summaries were also observed for H&E-based methods, like Klintrup-Makinen grade (DFS: HR 0.62; 95%CI: 0.43-0.88). Furthermore, inflammatory assessments were independent of MSI status.

CONCLUSION

The evidence suggests that it is the density of a co-ordinated local inflammatory infiltrate that confers survival benefit, rather than any individual immune cell subtype. Furthermore, the location of individual cells within the tumour microenvironment does not appear to influence survival. The authors advocate a standardised assessment of the local inflammatory response, but caution against emphasizing the importance of any individual immune cell subtype.

Targeting Tumor Microenvironment by Small-Molecule Inhibitors

The tumor microenvironment (TME) is a hypoxic, acidic, and immune/inflammatory cell–enriched milieu that plays crucial roles in tumor development, growth, progression, and therapy resistance. Targeting TME is an attractive strategy for the treatment of solid tumors. Conventional cancer chemotherapies are mostly designed to directly kill cancer cells, and the effectiveness is always compromised by their penetration and accessibility to cancer cells. Small-molecule inhibitors, which exhibit good penetration and accessibility, are widely studied, and many of them have been successfully applied in clinics for cancer treatment. As TME is more penetrable and accessible than tumor cells, a lot of efforts have recently been made to generate small-molecule inhibitors that specifically target TME or the components of TME or develop special drug-delivery systems that release the cytotoxic drugs specifically in TME. In this review, we briefly summarize the recent advances of small-molecule inhibitors that target TME for the tumor treatment.

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Tumor microenvironment (TME) is an indispensable part of tumor and is an important therapeutic target.

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TME is more penetrable and accessible than tumor cell area.

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Small-molecule inhibitors that target TME are very promising.

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The target efficiency can be improved by specific deliver and release systems.

Prognostic Value of Lymphocyte-Activation Gene 3 (LAG3) in Cancer: A Meta-Analysis

Introduction: Therapeutic targeting of inhibitors of the immune response has reached the clinical setting. Inhibitors of the novel receptor LAG3, which negatively regulates T-cell activation, are under investigation. Here we explore the presence and prognostic role of LAG3 in cancer.

Methods: A systematic search of electronic databases identified publications exploring the effect of LAG3 on overall survival (OS) and (for early-stage cancers) disease-free survival (DFS). Hazard ratios (HR) were pooled in a meta-analysis using generic inverse-variance and random effect modeling. Subgroup analyses were conducted based on disease site and tumor type.

Results: Fifteen studies met the inclusion criteria. LAG3 was associated with better overall survival [HR 0.81, 95% confidence interval (CI) 0.66–0.99; P = 0.04], with subgroup analysis showing no significant differences between disease-site subgroups. The beneficial effect of LAG3 on OS was of greater magnitude in early-stage malignancies (HR 0.73, 95% CI 0.60–0.88) than in the metastatic setting (HR 1.20, 95% CI 0.70–2.05), but this difference was not statistically significant (subgroup difference p = 0.18). LAG3 did not have a significant association with DFS [HR 1.02, 95% confidence interval (CI) 0.77–1.37; P = 0.87], with subgroup analysis showing worse DFS in patients with lymphoma and improved DFS in those with breast cancer.

Conclusions: High expression of LAG3 is associated with favorable overall survival in several solid tumors. A trend toward an association in early-stage disease suggests the importance of immune surveillance in this setting.