Immunology and immunotherapy of colorectal cancer

The Spontaneous Regression of Primary Gastrointestinal Malignancies: An Observational Review

The spontaneous regression or remission (SR) of cancer, often described as the partial or complete disappearance of a malignant tumor in the absence of all medical treatment and therapy, is a well-documented phenomenon. With efforts ongoing to establish cancer treatments that limit undesirable outcomes and adverse effects, these uncommon occurrences of SR carry significant implications for novel therapies and warrant further investigation. While several case studies have reported instances of SR in gastrointestinal (GI) malignancies, a comprehensive review of previous manifestations of SR in the GI tract remains lacking. The inclusion criteria for the rare phenomenon are also in need of an appropriate update that takes recent scientific advancements and emerging new medical technologies into account. Our analysis of 390 cases of SR in the GI tract focuses primarily on neoplasms of the hepatobiliary system and proposes an updated version of the older inclusion criteria for spontaneous regression.

Exosomes: The protagonists in the tale of colorectal cancer?

Exosomes, which facilitate intercellular communication, antigen presentation and shuttling of biological agents, were initially thought as the cell's garbage cargo but today, after about 40 years of their discovery, we are now beginning to understand their potential role in diagnosis and therapy of several diseases including cancers. Various studies over the decades have signified the role of exosomes in different stages of cancer. Exosomes play a key role in colorectal cancer initiation (CRC), promotion of anti- apoptotic signaling pathways, regulating tumor microenvironment, enhancing tumorigenicity, promotion of angiogenesis, stem cell proliferation and endothelial cell migration, establishment of immune suppressive environment, formation of pre- metastatic niche and metastasis. Exosomes also elicits drug resistance. Since, they have the ability to cross the biological barrier, exosomes are now being explored as an efficient target specific drug delivery system that facilitates the shipping of different biomolecules and therapeutic drugs. However, cautious and strong investigative approaches are required before approving exosomes as therapeutics or drug delivery systems. In this review, we summarize the role of exosomes in different stages of CRC and also elaborate on the applications of exosomes in diagnosis and therapy with respect to CRC.

SIRT5 Contributes to Colorectal Cancer Growth by Regulating T Cell Activity

Over the past several years, SIRT5 has attracted considerable attention in metabolic regulation. However, the function of SIRT5 in tumorigenesis by regulating tumor microenvironment is poorly understood. In this work, we found that Sirt5 knockout mice were resistant to AOM and DSS-induced colitis-associated colorectal tumorigenesis and the level of IFN-γ in their tumor microenvironment was higher. Additionally, proteome and network analysis revealed that SIRT5 was important in the T cell receptor signaling pathway. Furthermore, we determined that a deficiency of Sirt5 induced stronger T cell activation and demonstrated that SIRT5 played a pivotal role in regulating the differentiation of CD4⁺ regulatory T (Treg) cells and T helper 1 (Th1) cells. An imbalance in the lineages of immunosuppressive Treg cells and the inflammatory Th1 subsets of helper T cells leads to the development of colon cancer. Our results revealed a regulatory role of SIRT5 in T cell activation and colorectal tumorigenesis.

An Immunoscore System Based On CD3+ And CD8+ Infiltrating Lymphocytes Densities To Predict The Outcome Of Patients With Colorectal Adenocarcinoma

Purpose

The aim of this study was to evaluate the Immunoscore (IS) methodology as a prognostic marker of colorectal adenocarcinoma in Tunisian population. Tumor blocks were retrospectively collected from 106 patients with sporadic colorectal cancer.

Methods

Immunohistochemical staining and images analysis software were used to quantify the density of CD3⁺ and CD8⁺ tumor-infiltrating lymphocytes in the center of the tumor and invasive margin.

Results

The density of CD3⁺ and CD8⁺ was significantly associated with 5-year overall survival (P=0.001 and P=0.00098, respectively) and 5-year disease-free survival (P=0.0006 and P=0.0056, respectively). The earlier stage and the absence of vascular emboli showed a significant association with IS analysis. Cox multivariate regression analysis revealed that Immunoscore (from I0 to I4) was more significantly correlated with overall survival (P=0.00011) and disease-free survival (P=0.0008) than Tumor-Node-Metastasis (TNM) staging (P=0.057 and P=0.039, respectively). Patients with low IS were associated with inferior disease-free survival and overall survival, contrary to patients with high IS.

Conclusion

This is the first study which evaluated the prognostic value of IS methodology in colorectal cancer in African and Arabic population. The IS methodology carries out in this study allows to estimate the risk of relapse in patients with colorectal cancer. Overall, our results support the implementation of the consensus Immunoscore as a new component for the classification of cancer, designated TNM-Immune.

TH9, TH17, and TH22 Cell Subsets and Their Main Cytokine Products in the Pathogenesis of Colorectal Cancer

In recent years, several newly identified T helper (T_H) cell subsets, such as T_H9, T_H17, and T_H22 cells, and their respective cytokine products, IL-9, IL-17, and IL-22, have been reported to play critical roles in the development of chronic inflammation in the colorectum. Since chronic inflammation is a potent driving force for the development of human colorectal cancer (CRC), the contributions of T_H9/IL-9, T_H17/IL-17, and T_H22/IL-22 in the pathogenesis of CRC have recently become an increasingly popular area of scientific investigation. Extensive laboratory and clinical evidence suggests a positive relationship between these new T_H subsets and the growth and formation of CRC, whereas, administration of IL-9, IL-17, and IL-22 signaling inhibitors can significantly alter the formation of colorectal chronic inflammation or CRC lesions in animal models, suggesting that blocking these cytokine signals might represent promising immunotherapeutic strategies. This review summarizes recent findings and currently available data for understanding the vital role and therapeutic significance of T_H9/IL-9, T_H17/IL-17, and T_H22/IL-22 in the development of colorectal tumorigenesis.

Assessment of Serum Levels of the Adipocytokine Chemerin in Colorectal Cancer Patients

Background

Colorectal cancer (CRC) is one of the most common cancers worldwide. The tumor microenvironment is very important for determining cancer cell growth and spreading. Chemerin, a newly identified adipokine secreted by adipose tissue, is known to be associated with obesity, metabolic syndrome, and insulin resistance. The present study was carried out to investigate the association between serum levels of chemerin and colorectal cancer.

Methods

Thirty-two patients with colorectal cancer aged 57.6±6.5 years, and twenty age, sex and BMI matched healthy controls were included in the study. Serum che me rin levels were determined using enzyme linked immuno sorbent assay. C-reactive protein (CRP) levels were determined using a turbidimetric immunoassay. Carcino embryonic antigen (CEA) and carbohydrate antigen (CA 19-9) were measured by radioimmunoassay.

Results

Chemerin levels were found to be significantly higher in patients relative to the controls (P<0.001) and gradually increased with the TNM tumor stage progression. The mean CRP, CEA and CA 19-9 levels were also significantly higher in patients (P<0.001). There was a significant correlation between the serum levels of chemerin and the other measured parameters in CRC patients. The area under receiver operating characteristic curve (ROC) for serum chemerin was 1 at a cut-off value ≥ 161.5 with 100% sensitivity and 100% specificity.

Conclusions

Conclusions: The observed results suggest that chemerin may have a potential role in the pathogenesis and progression of colorectal malignancy and may be a good biomarker of colorectal cancer and stage progression.

Evolving notions on immune response in colorectal cancer and their implications for biomarker development

INTRODUCTION

Colorectal cancer (CRC) still represents the third most commonly diagnosed type of cancer in men and women worldwide. CRC is acknowledged as a heterogeneous disease that develops through a multi-step sequence of events driven by clonal selections; this observation is sustained by the fact that histologically similar tumors may have completely different outcomes, including a varied response to therapy.

METHODS

In "early" and "intermediate" stage of CRC (stages II and III, respectively) there is a compelling need for new biomarkers fit to assess the metastatic potential of their disease, selecting patients with aggressive disease that might benefit from adjuvant and targeted therapies. Therefore, we review the actual notions on immune response in colorectal cancer and their implications for biomarker development.

RESULTS

The recognition of the key role of immune cells in human cancer progression has recently drawn attention on the tumor immune microenvironment, as a source of new indicators of tumor outcome and response to therapy. Thus, beside consolidated histopathological biomarkers, immune endpoints are now emerging as potential biomarkers.

CONCLUSIONS

The introduction of immune signatures and cellular and molecular components of the immune system as biomarkers is particularly important considering the increasing use of immune-based cancer therapies as therapeutic strategies for cancer patients.

Proteomic Features of Colorectal Cancer Identify Tumor Subtypes Independent of Oncogenic Mutations and Independently Predict Relapse-Free Survival

BACKGROUND

The directed study of the functional proteome in colorectal cancer (CRC) has identified critical protein markers and signaling pathways; however, the prognostic relevance of many of these proteins remains unclear.

METHODS

We determined the prognostic implications of the functional proteome in 263 CRC tumor samples from patients treated at MD Anderson Cancer Center (MDACC) and 462 patients from The Cancer Genome Atlas (TCGA) to identify patterns of protein expression that drive tumorigenesis. A total of 163 validated proteins were analyzed by reverse phase protein array (RPPA). Unsupervised hierarchical clustering of the tumor proteins from the MDACC cohort was performed, and clustering was validated using RPPA data from TCGA CRC. Cox regression was used to identify predictors of tumor recurrence.

RESULTS

Clustering revealed dichotomization, with subtype A notable for a high epithelial-mesenchymal transition (EMT) protein signature, while subtype B was notable for high Akt/TSC/mTOR pathway components. Survival data were only available for the MDACC cohort and were used to evaluate prognostic relevance of these protein signatures. Group B demonstrated worse relapse-free survival (hazard ratio 2.11, 95% confidence interval 1.04-4.27, p = 0.039), although there was no difference in known genomic drivers between the two proteomic groups. Proteomic grouping and stage were significant predictors of recurrence on multivariate analysis. Eight proteins were found to be significant predictors of tumor recurrence on multivariate analysis: Collagen VI, FOXO3a, INPP4B, LcK, phospho-PEA15, phospho-PRAS40, Rad51, phospho-S6.

CONCLUSION

CRC can be classified into distinct subtypes by proteomic features independent of common oncogenic driver mutations. Proteomic analysis has identified key biomarkers with prognostic importance, however these findings require further validation in an independent cohort.

Immunotherapy as a Potential Treatment for Chordoma: a Review

Chordoma is a locally aggressive primary malignancy of the axial skeleton. The gold standard for treatment is en bloc resection, with some centers now advocating for the use of radiation to help mitigate the risk of recurrence. Local recurrence is common, and salvaging local failures is quite difficult. Chemotherapy has been ineffective and small molecule targeted therapy has had only marginal benefits in small subsets of patients with rare tumor phenotypes or refractory disease. Recent successes utilizing immunotherapy in a variety of cancers has led to a resurgence of interest in modifying the host immune system to develop new ways to treat tumors. This review will discuss these studies and will highlight the early studies employing immune strategies for the treatment of chordoma.

Review on the immunotherapy strategies against metastatic colorectal carcinoma

Colorectal cancer (CRC) is one of the most common malignancies throughout the world and the leading cause of cancer-related mortality in Western countries. Recent progress in CRC treatment options, such as surgery, chemotherapy, radiotherapy and target therapy, has improved the prognosis, but advanced disease with recurrence or distant metastasis is usually incurable and has an unfavorable prognosis. The introduction of immunotherapy-associated strategies, both active and passive, to the treatment of CRC aims to overcome the limits of classical treatments. We review the state of the art for CRC with respect to different immunotherapeutic approaches, such as the use of cancer vaccines and/or adoptive cellular therapy, their most current advances and limitations and perspectives for further improvements.

Soluble NKG2D ligands are biomarkers associated with the clinical outcome to immune checkpoint blockade therapy of metastatic melanoma patients

The introduction of immune checkpoint blockade into the clinical practice resulted in improvement of survival of a significant portion of melanoma patients. Consequently, predictive biomarkers of response are needed to optimize patient's stratification and the development of combination therapies. The aim of this study was to determine whether levels of soluble NKG2D ligands (MICA, MICB, ULBP1, 2 and 3; sNKG2DLs) in the serum of melanoma patients can serve as useful predictors of response to the treatment with immune checkpoint blockade. sNKG2DLs were measured by ELISA in baseline and post-treatment serum and these results were correlated with the clinical outcome of melanoma patients (N = 194). The same determinations were performed also in a cohort of patients (N = 65) treated with either chemotherapy, radiotherapy, or mutated BRAF inhibitors (BRAFi). Absence of soluble MICB and ULBP-1 in baseline serum correlated with improved survival (OS = 21.6 and 25.3 mo and p = 0.02 and 0.01, respectively) of patients treated with immunological therapies while detectable levels of these molecules were found in poor survivors (OS = 8.8 and 12.1 mo, respectively). Multivariate analysis showed that LDH (p <0.0001), sULBP-1 (p = 0.02), and sULBP-2 (p = 0.02) were independent predictors of clinical outcome for the cohort of melanoma patients treated with immune checkpoint blockade. Only LDH but not sNKG2DLs was significantly associated with the clinical outcome of patients treated with standard or BRAFi regimens. These findings highlight the relevance of sNKG2DLs in the serum of melanoma patients as biomarkers for patients' stratification and optimization of immune checkpoint inhibition regimens.

Viroimmunotherapy for Colorectal Cancer: Clinical Studies

Colorectal cancer is a leading cause of cancer incidence and death. Therapies for those with unresectable or recurrent disease are not considered curative at present. More effective and less toxic therapies are desperately needed. Historically, the immune system was thought to be an enemy to oncolytic viral therapy. Thinking that oncolysis would be the only mechanism for cell death, oncolytic virologists theorized that immune clearance was a detriment to oncolysis. Recent advances in our understanding of the tumor microenvironment, and the interplay of tumor survival and a patient's immune system have called into question our understanding of both arenas. It remains unclear what combination of restrictions or enhancements of innate and/or cell-mediated immunity can yield the highest likelihood of viral efficacy. This article reviews the variety of mechanisms explored for viruses such as immunotherapy for colorectal cancer.

KIR genes and HLA class I ligands in a Caucasian Brazilian population with colorectal cancer

Colorectal cancer (CRC) can occur anywhere in the colon or rectum and represents the third most common cancer in the world in both sexes. Natural killer cells (NK) are part of the innate immune system recognizing class I HLA molecules on target cells through their membrane receptors, called killer cell immunoglobulin-like receptors (KIR). The aim of our study was to evaluate the association between the KIR genes and HLA ligands in patients with colorectal cancer and healthy controls. We examined the polymorphism of 16 KIR genes and their HLA ligands in 154 caucasoid CRC patients and 216 controls. When both groups were compared, no significant differences were found for HLA ligands and KIR genes after Bonferroni correction. However, the Bx haplotypes (heterozygous and homozygous for the haplotype B) were more frequent in controls, when compared with patients. These findings suggest that individuals with Bx haplotypes could have some protection to colorectal cancer. The hypothesis is not related with the presence of a special KIR gene and HLA ligand related to the disease, but to the presence of several activating genes in the individuals with no better action of one in relation to other. Further studies to confirm this observation are warranted.

CD9 Expression in Colorectal Carcinomas and Its Prognostic Significance

Background

CD9, a member of the tetraspanin superfamily, is a tumor suppressor in many malignancies. The aim of this study was to evaluate the immunohistochemical expression of CD9 in colorectal carcinomas (CRCs) and determine clinicopathological and prognostic significance of its expression.

Methods

The CD9 expression status of 305 CRCs was evaluated using a semi-quantitative scoring system in tumor cells (T-CD9) and immune cells (I-CD9) by classifying the results as high and low expression.

Results

High T-CD9 (T-CD9 [+]) expression was detected in 175 samples (57.6%) and high I-CD9 (I-CD9 [+]) expression was detected in 265 samples (86.9%). Using Kaplan-Meier survival analysis, the T-CD9 (+) group showed a tendency for better disease-free survival (DFS) (p = .057). In left-sided tumors, DFS was significantly longer in the T-CD9 (+) group (p = .021) but no statistical significance was observed with right-sided tumors (p = .453). I-CD9 (+) CRCs significantly correlated with well/moderately differentiation (p = .014). In Kaplan-Meier analysis, the I-CD9 (+) group had a tendency towards worse DFS compared to the I-CD9 (–) group (p = .156). In combined survival analysis of T-CD9 and I-CD9, we found that the longest DFS was among patients in the T-CD9 (+)/I-CD9 (–) group, whereas the T-CD9 (–)/I-CD9 (+) group showed the shortest DFS (p = .054).

Conclusions

High expression of T-CD9 was associated with a favorable DFS, especially in left-sided CRCs. Combined evaluation of T-CD9 and I-CD9 is required to determine the comprehensive prognostic effect of CD9 in CRCs.

Genomic Analysis of Immune Cell Infiltrates Across 11 Tumor Types

BACKGROUND

Immune infiltration of the tumor microenvironment has been associated with improved survival for some patients with solid tumors. The precise makeup and prognostic relevance of immune infiltrates across a broad spectrum of tumors remain unclear.

METHODS

Using mRNA sequencing data from The Cancer Genome Atlas (TCGA) from 11 tumor types representing 3485 tumors, we evaluated lymphocyte and macrophage gene expression by tissue type and by genomic subtypes defined within and across tumor tissue of origin (Cox proportional hazards, Pearson correlation). We investigated clonal diversity of B-cell infiltrates through calculating B-cell receptor (BCR) repertoire sequence diversity. All statistical tests were two-sided.

RESULTS

High expression of T-cell and B-cell signatures predicted improved overall survival across many tumor types including breast, lung, and melanoma (breast CD8_T_Cells hazard ratio [HR] = 0.36, 95% confidence interval [CI] = 0.16 to 0.81, P = .01; lung adenocarcinoma B_Cell_60gene HR = 0.71, 95% CI = 0.58 to 0.87, P = 7.80E-04; melanoma LCK HR = 0.86, 95% CI = 0.79 to 0.94, P = 6.75E-04). Macrophage signatures predicted worse survival in GBM, as did B-cell signatures in renal tumors (Glioblastoma Multiforme [GBM]: macrophages HR = 1.62, 95% CI = 1.17 to 2.26, P = .004; renal: B_Cell_60gene HR = 1.17, 95% CI = 1.04 to 1.32, P = .009). BCR diversity was associated with survival beyond gene segment expression in melanoma (HR = 2.67, 95% CI = 1.32 to 5.40, P = .02) and renal cell carcinoma (HR = 0.36, 95% CI = 0.15 to 0.87, P = .006).

CONCLUSIONS

These data support existing studies suggesting that in diverse tissue types, heterogeneous immune infiltrates are present and typically portend an improved prognosis. In some tumor types, BCR diversity was also associated with survival. Quantitative genomic signatures of immune cells warrant further testing as prognostic markers and potential biomarkers of response to cancer immunotherapy.

The clinical impact of ICOS signal in colorectal cancer patients

The inducible T-cell co-stimulator (ICOS) belongs to the B7-CD28 immunoglobulin superfamily, which is currently the subject of intense study due to great successes gained in treatment of different malignancies by disrupting their family members. However, the role of ICOS played in colorectal cancer (CRC) remains poorly understood. A tissue microarray (n = 310) was stained with the ICOS specific antibody and ICOS expression is decreased in patients with either lymphatic or distant metastasis and inversely associated with CEA level and TNM stage of CRC patients. Importantly, high ICOS expression is significantly correlated with overall survival (OS) of CRC patients (n = 230, p < 0.001), and ICOS expression is also proved to be an independent prognostic factor by multivariate analysis. Surgical excised CRC specimens (n = 26) were enzymatically digested to get the tumor-infiltrating leukocytes and ICOS is mainly expressed on CD4(+) T cells and its ligand ICOSL is detected on macrophages and tumor cells. ICOS expression level is associated with increased cytotoxic T lymphocyte antigen (CTLA)-4 (p < 0.001) and programmed death (PD-1) (p = 0.005) expression on T cells and more infiltrated CD8(+) T cells (p < 0.001). Interestingly, ICOS(+)CD4(+) cells isolated from tumor tissues have high T-bet and interferon (IFN)γ expression, the characteristics of Th1 cells, compared to ICOS(-)CD4(+) cells. In addition, the correlation between the percentage of ICOS(+)CD4(+) T cells in tumor tissue and peripheral blood was detected. Conclusively, expression of ICOS is associated with improved survival in CRC and percentage of ICOS(+)CD4(+) cells acting as Th1 cells in either primary tumor tissue or peripheral blood may be a clinical biomarker for good prognosis of CRC patients.

Dendritic cell defects in the colorectal cancer

Colorectal cancer (CRC) results from the accumulation of both genetic and epigenetic alterations of the genome. However, also the formation of an inflammatory milieu plays a pivotal role in tumor development and progression. Dendritic cells (DCs) play a relevant role in tumor by exerting differential pro-tumorigenic and anti-tumorigenic functions, depending on the local milieu. Quantitative and functional impairments of DCs have been widely observed in several types of cancer, including CRC, representing a tumor-escape mechanism employed by cancer cells to elude host immunosurveillance.

Understanding the interactions between DCs and tumors is important for comprehending the mechanisms of tumor immune surveillance and escape, and provides novel approaches to therapy of cancer. This review summarizes updated information on the role of the DCs in colon cancer development and/or progression.

Generation of tumor-specific cytotoxic T-lymphocytes from the peripheral blood of colorectal cancer patients for adoptive T-cell transfer

This study designs a strategy for an adoptive cellular therapy (ACT) protocol based on the ex-vivo selection of autologous peripheral blood-derived CD8-enriched T-cells, stimulated with dendritic cells (DCs) that had been pulsed with apoptotic tumor cells to generate cytotoxic T lymphocytes (CTLs) with anti-tumor activity. Seventy-eight colorectal cancer (CRC) patients were enrolled in this study. Tumor tissues and peripheral blood (PB) were obtained at surgery. Tissues were mechanically dissociated and cultured to obtain a primary tumor cell line from each patient. DCs were derived from peripheral blood mononuclear cells (PBMCs) using magnetic positive selection of CD14+ monocytes. Anti-tumor CTLs were elicited in co-/micro-cultures using DCs as antigen-presenting cells, autologous apoptotic tumor cells as a source of antigens, and CD8+ T lymphocytes as effectors. Interferon-γ (IFN-γ) secretion was assessed by ELISpot assays to evaluate the activation of the CTLs against the autologous tumor cells. Primary tumor cell lines were obtained from 20 of 78 patients (25.6%). DCs were generated from 26 patients, and of them, corresponding tumor cell lines were derived from six patients. ELISpot results showed that significant IFN-γ secretion was detected after different numbers of stimulations for two patients, whereas weak secretion was observed for three patients. Despite difficulties due to contamination of several primary tumor cell lines with gut intestinal flora, the results suggest that the generation of tumor-specific CTLs is feasible from patients with CRC, and could be useful for supporting an ACT approach in CRC.

Image analyzer-based assessment of tumor-infiltrating T cell subsets and their prognostic values in colorectal carcinomas

To find useful tools to evaluate the prognosis in colorectal carcinoma (CRC) patients, we investigated the prognostic values of tumor-infiltrating T lymphocyte subsets according to intratumoral subsites as well as clinical or molecular characteristics. Immunohistochemistry for CD8, CD45RO, and FOXP3 was performed, and densities of the T cell subsets in each tissue microarray core (cells/mm2) were measured by image analysis. In the training set (n = 218) of CRC, T cell subset densities in the invasion front were more strongly associated with patient outcome than those in the tumor center. In the validation set (n = 549), T cell subset densities in the invasion front were evaluated. Univariate analysis showed that all three T cell subset densities were significantly associated with longer progression free survival and overall survival time (p < 0.001). In multivariate analysis, a high CD45RO density correlated independently with longer progression free survival (p = 0.011) and overall survival time (p = 0.007) in CRC patients, regardless of tumor location or adjuvant chemotherapy status. Our results showed that CD45RO density in the invasion front was the only independent prognostic factor regarding CRC. However, CD8 and FOXP3 densities were also independent prognostic factors in certain clinical settings. Thus, image analysis of tissue microarray cores in the invasion front of CRC could be used as a valid method for evaluating the prognostic significance of T cell subset densities.

Low molecular weight hyaluronan-pulsed human dendritic cells showed increased migration capacity and induced resistance to tumor chemoattraction

We have shown that ex vivo pre-conditioning of bone marrow-derived dendritic cells (DC) with low molecular weight hyaluronan (LMW HA) induces antitumor immunity against colorectal carcinoma (CRC) in mice. In the present study we investigated the effects of LMW HA priming on human-tumor-pulsed monocytes-derived dendritic cells (DC/TL) obtained from healthy donors and patients with CRC. LMW HA treatment resulted in an improved maturation state of DC/TL and an enhanced mixed leucocyte reaction activity in vivo. Importantly, pre-conditioning of DC/TL with LMW HA increased their ability to migrate and reduced their attraction to human tumor derived supernatants. These effects were associated with increased CCR7 expression levels in DC. Indeed, a significant increase in migratory response toward CCL21 was observed in LMW HA primed tumor-pulsed monocyte-derived dendritic cells (DC/TL/LMW HA) when compared to LWM HA untreated cells (DC/TL). Moreover, LMW HA priming modulated other mechanisms implicated in DC migration toward lymph nodes such as the metalloproteinase activity. Furthermore, it also resulted in a significant reduction in DC migratory capacity toward tumor supernatant and IL8 in vitro. Consistently, LMW HA dramatically enhanced in vivo DC recruitment to tumor-regional lymph nodes and reduced DC migration toward tumor tissue. This study shows that LMW HA--a poorly immunogenic molecule--represents a promising candidate to improve human DC maturation protocols in the context of DC-based vaccines development, due to its ability to enhance their immunogenic properties as well as their migratory capacity toward lymph nodes instead of tumors.

T-box transcription factors in cancer biology

The evolutionarily conserved T-box family of transcription factors have critical and well-established roles in embryonic development. More recently, T-box factors have also gained increasing prominence in the field of cancer biology where a wide range of cancers exhibit deregulated expression of T-box factors that possess tumour suppressor and/or tumour promoter functions. Of these the best characterised is TBX2, whose expression is upregulated in cancers including breast, pancreatic, ovarian, liver, endometrial adenocarcinoma, glioblastomas, gastric, uterine cervical and melanoma. Understanding the role and regulation of TBX2, as well as other T-box factors, in contributing directly to tumour progression, and especially in suppression of senescence and control of invasiveness suggests that targeting TBX2 expression or function alone or in combination with currently available chemotherapeutic agents may represent a therapeutic strategy for cancer.

Defective generation and maturation of dendritic cells from monocytes in colorectal cancer patients during the course of disease

Colorectal cancer (CRC) is the second-leading cause of cancer-related deaths in Western countries. Today, the role of the host’s immune system in controlling the progression and spread of solid tumors is broadly established. Tumor immunosurveillance escape mechanisms, such as those involving dendritic cells (DCs), the most important antigen-presenting cells, are likewise recognized processes involved in cancer. The present study evaluates the ability of CRC patients to generate DCs in vitro from circulating monocytes at both pre- and post-operative timepoints; the results are correlated with the stage of disease to shed light on the systemic immune statuses of CRC patients. Our data showed that patients’ DCs had lower co-stimulatory molecule expression and were less able to present antigens to allogeneic T cells compared to healthy controls’ (HC) DCs. Furthermore altered cytokine secretion, such as increased IL-10 and reduced IL-12 and TNF-α, was observed. At the post-operative timepoints we observed a recovery of the patients’ ability to generate immature DCs, compared to HCs, but the maturational capacity remained affected. Our study conclusively highlights the persistently impaired in vitro generation of fully mature and functional DCs, which appears to be more altered during advanced stages. This work sheds light on a dendritic cell-based tumor immune escape mechanism that could be useful for the development of more effective immunotherapeutic strategies.

Quantification of blood dendritic cells in colorectal cancer patients during the course of disease

Colorectal cancer is a malignancy with poor prognosis that might be associated with defective immune function. The aim of the present study was to investigate circulating dendritic cells in colorectal cancer patients, in order to contribute to elucidate tumor-escape mechanisms and to point out a possible correlation with the clinical condition of the disease. Therefore, we enumerated ex vivo myeloid and plasmacytoid dendritic cells, through multicolor flow cytometry, in 26 colorectal patients and 33 healthy controls. Furthermore we performed several analyses at determined time points in order to define the immunological trend of cancer patients after surgery and other conventional treatments. At the pre-operative time point the absolute number of plasmacytoid dendritic cells in cancer patients was significantly reduced in comparison to controls, this result being mainly referred to stage III-IV patients. The number of myeloid dendritic cells did not show any significant difference compared to healthy controls; interestingly the expression of the tolerogenic antigen CD85k was significantly higher on cancer patients' myeloid dendritic cells than controls'. At the following samplings, circulating dendritic cell absolute number did not show any difference compared to controls. Conclusively the impairment of the number of circulating dendritic cells may represent one of the tumor escape mechanisms occurring in colorectal cancer. These alterations seem to be correlated to cancer progression. Our work sheds light on one of dendritic cell-based tumor immune escape mechanisms. This knowledge may be useful to the development of more effective immunotherapeutic strategies.

From the immune contexture to the Immunoscore: the role of prognostic and predictive immune markers in cancer

The inherent complexity of multifactorial diseases such as cancer renders the process of patient prognosis and prediction of response to therapy extremely difficult. Many markers, signatures, and methods have been described to evaluate the prognosis of cancer patients, yet very few translate into the clinic. Systems biology approaches have facilitated analysis of the complex interaction between tumors and the host-immune response, and allowed the definition of the immune contexture. Here we review the potential of the immune contexture, quantified by the Immunoscore, to provide a statistically strong parameter for prognosis. Finally we introduce the concept that the host-immune reaction could be the critical element in determining response to therapy. The effect on the immune response could be the underlying factor behind many of the predictive markers.

The structure of the von Willebrand factor is not altered in patients with colorectal carcinoma

AIM

Elevated levels of von Willebrand factor (VWF) are often observed in many diseases including colorectal cancer, but this finding is not definite. The aim of our study was to examine the change in VWF multimer distribution in patients with colorectal cancer.

METHOD

We randomly selected nine patients from each of the four Union for International Cancer Control (UICC) stages of colon cancer. VWF antigen (VWF:Ag), VWF-cleaving protease ADAMTS-13 level and factor VIII activity (FVIII:C) were determined. The multimer distribution of VWF was visualized using electrophoretic multimer analysis.

RESULTS

The VWF multimer structure was normal with no difference between the four UICC stages. There was no significant increase in VWF:Ag and FVIII:C levels in the more advanced UICC stages. There was no significant difference in the ADAMTS-13 level according to the UICC stage.

CONCLUSION

There was no change in the VWF multimer distribution to indicate acquired von Willebrand disease.

Monocytes expression of IL-12 related and IL-10 genes in association with development of colorectal cancer

The main regulator of anti-tumor immune response is the activity of monocytes, suggesting that the produced cytokines may have a prognostic role. This study investigates gene expression of interleukin (IL)-12-related cytokine and IL-10 in stimulated monocytes from colorectal cancer (CRC) patients. Relative quantification of IL-12A, IL-12B, IL-23A and IL-10 mRNA transcripts was performed on the third hours after stimulation by real-time qPCR. We also explored an inhibitor of JNK signaling pathway activation for the observed cytokine gene expression. A strong downregulation of IL-12B mRNA expression in CRC monocytes compared to healthy donors was observed. The rate of transcription of IL-12B in stimulated monocytes was associated with the stage of CRC. The expression of IL-12A gene in stimulated monocytes from patients with advanced was lower than early cancer. Moreover, we observed stage dependent JNK inhibition mediated reduction in IL-12A expression. The hyporesponsiveness was strongly expressed in monocytes from advanced then early stages of CRC. Expression of IL-10 mRNA was almost equally in CRC monocytes from early stages and healthy donors. We demonstrated that altered gene expression profiles of IL-12A, IL-12B, IL-23A at mRNA level in CRC monocytes was associated with tumor development and can be attributed to anticancer immune response.

The immune contexture in human tumours: impact on clinical outcome

Tumours grow within an intricate network of epithelial cells, vascular and lymphatic vessels, cytokines and chemokines, and infiltrating immune cells. Different types of infiltrating immune cells have different effects on tumour progression, which can vary according to cancer type. In this Opinion article we discuss how the context-specific nature of infiltrating immune cells can affect the prognosis of patients.

Colorectal cancer vaccines in clinical trials

This article elucidates current strategies of active immunotherapy for colorectal cancer patients with a focus on T-cell mediated immunotherapy. Poor prognosis of especially stage III and IV colorectal cancer patients emphasizes the need for advanced therapeutic intervention. Here, we refer to clinical trials using either tumor cell-derived vaccines or tumor antigen vaccines with a special interest on safety, induced immune responses, clinical benefit and efforts to improve the clinical impact of these vaccines in the context of colorectal cancer treatment.

Low molecular weight hyaluronan preconditioning of tumor-pulsed dendritic cells increases their migratory ability and induces immunity against murine colorectal carcinoma

We have recently shown that systemic administration of low molecular weight hyaluronan (LMW HA) significantly reduces colorectal carcinoma (CRC) growth in vivo. The elicited response is partially mediated by activated dendritic cells (DC). To potentiate the ability of DC loaded with whole tumor lysate (DC/TL) to induce immunity against CRC in mice, we aimed to study the effects of preconditioning DC with LMW HA for therapeutic vaccination. LMW HA improved maturation of ex vivo generated DC, increased IL-12, decreased IL-10 production, and enhanced a MLR activity in vitro. Although TNF-α showed a similar capacity to mature DC, preconditioning of DC/TL with LMW HA increased their ability to migrate in vitro toward CCL19 and CCL-21 in a CD44- and a TLR4-independent manner; this effect was superior to Poly(I:C), LPS, or TNF-α and partially associated with an increase in the expression of CCR7. Importantly, LMW HA dramatically enhanced the in vivo DC recruitment to tumor-regional lymph nodes. When these LMW HA-treated CRC tumor lysate-pulsed DC (DC/TL/LMW HA) were administered to tumor-bearing mice, a potent antitumor response was observed when compared to DC pulsed with tumor lysate alone and matured with TNF-α. Then, we showed that splenocytes isolated from animals treated with DC/TL/LMW HA presented a higher proliferative capacity, increased IFN-γ production, and secreted lower levels of the immunosuppressive IL-10. Besides, increased specific CTL response was observed in DC/TL/LMW HA-treated animals and induced long-term protection against tumor recurrence. Our data show that LMW HA is superior to other agents at inducing DC migration; therefore, LMW HA could be considered a new adjuvant candidate in the preparation of DC-based anticancer vaccines with potent immunostimulatory properties.

Tumor immunosurveillance in human cancers

Until now, the anatomic extent of tumor (TNM classification) has been by far the most important factor to predict the prognosis of colorectal cancer patients. However, in recent years, data collected from large cohorts of human cancers demonstrated that the immune contexture of the primary tumors is an essential prognostic factor for patients’ disease-free and overall survival. Tumoral and immunological markers predicted by systems biology methods are involved in the shaping of an efficient immune reaction and can serve as targets for novel therapeutic approaches. Global analysis of tumor microenvironment showed that the nature, the functional orientation, the density, and the location of adaptive immune cells within distinct tumor regions influence the risk of relapse events. The density and the immune cell location within the tumor have a prognostic value that is superior to the TNM classification, and tumor invasion is statistically dependent on the host-immune reaction. Thus, the strength of the immune reaction could advance our understanding of cancer evolution and have important consequences in clinical practice.

Increased numbers of tumor-lysing monocytes in cancer patients

Lymphatic infiltration is a well known phenomenon in different tumors including endocrine malignancies. However, little is known about the role of antigen-presenting cells and T cell activation in this context. The aim of our study was to investigate the quantity and function of CD14+/CD56+ monocytes in tumor patients including endocrine malignancies. First, these cells were characterized in peripheral blood of endocrine and non-endocrine cancer patients as well as in tumor tissue samples. Cancer patients had in mean 3.7 times more CD14+/CD56+ monocytes in the peripheral blood compared to healthy controls (p≤0.0001), while the highest frequencies were seen in patients with heavy tumor load. Importantly, these cells additionally expressed several NK cell markers. A proof of CD14+/CD56+ infiltrations into papillary thyroid carcinoma was shown by immunohistochemical analyses. Functional analyses revealed an apoptosis inducing capacity in vitro after IFN-α re-stimulation. Our data indicate the importance of tumor-lysing monocytes in antitumor immunity.

A Phase I safety study of plasmid DNA immunization targeting carcinoembryonic antigen in colorectal cancer patients

A plasmid DNA vaccine, encoding a truncated form of human CEA fused to a T-helper epitope (CEA66 DNA) was delivered three times intradermally at 2 mg or intramuscularly at 8 mg by Biojector® to patients with colorectal cancer. Prior to the first vaccination, all patients received cyclophosphamide (300 mg/m²) intravenously. Granulocyte-macrophage colony-stimulating factor (GM-CSF) was administered subcutaneously with each vaccination. All patients completed the vaccine schedule. There were no grade 3 or 4 adverse events (AE). The most frequently reported AE grades 1 and 2 were injection site reactions, fatigue, headache, arthralgia, chest tightness and myalgia. Vaccination with CEA66 DNA in combination with GM-CSF was well tolerated and no signs of autoimmunity have been detected.

Tumor-reactive CD4+ CD8αβ+ CD103+ αβT cells: a prevalent tumor-reactive T-cell subset in metastatic colorectal cancers

High level of T-cell infiltration in colorectal carcinomas (CRCs) is a good prognostic indicator, but the tumor reactivity of this infiltrate (tumor infiltrating lymphocytes [TIL]) is poorly documented. This study examined the presence, phenotype and functional features of tumor-reactive lymphocytes in human CRC. Freshly dissociated TIL and T cell lines were isolated from CRC samples and from some paired normal colonic mucosa. Four tumor cell lines were obtained. Autologous tumor reactivity of CRC TIL and tumor-reactive cell features were analyzed. We demonstrate the presence among CRC TIL of variable fractions (up to 18%) of double positive CD4(+) CD8αβ(+) (DP) αβ T cells. Interestingly, a high proportion (16-20%) of this TIL subset displayed tumor reactivity, whilst this was the case for no or few single positive TIL. Low levels of DP TIL were found in most CRC samples and in normal colonic mucosa, but these cells were higher in metastatic CRC. Furthermore, we showed that DP TIL were polyclonal, restricted by HLA class-I, proliferated poorly and secreted higher amounts of IL-4 and IL-13 than single positive T cells, on cognate or CD3 stimulation. DP CRC TIL also expressed CD103, confirming their mucosal origin. Increased frequencies of tumor-reactive DP TIL in metastatic CRC suggest that these cells play a role in the metastatic process of this cancer. Based on their high secretion of IL-4 and IL-13 and on previously described roles of these cytokines in cancers, we postulate that DP TIL could favor CRC growth or metastasis and/or downmodulate immune responses to these tumors.

Distinct compartmental distribution of mature and immature dendritic cells in esophageal squamous cell carcinoma

Dendritic cells (DCs) play a critical role in generating anti-tumor immunity. DC functional defect has been related to the growth and progression of various human cancers. In esophageal squamous cell carcinoma (ESCC), the examination of DCs using immunohistochemistry (IHC) with anti-S100 antibody has demonstrated an increased infiltration of DCs into the tumor mass, however, the distribution patterns of DCs at different maturation states in ESCC are not fully evaluated. In this study, we immunohistochemically analyzed the DC maturation status by examining the S100-positive DCs, CD1alpha-positive immature DCs (iDCs), and CD208-positive mature DCs (mDCs) and their distribution patterns in 45 ESCCs and 10 control tissues. The IHC analysis showed that the number of S100-positive DCs was increased in both the cancer epithelium and tumor stroma. Further phenotypic analyses revealed that intraepithelial DCs in the cancer mass were predominantly CD1alpha-positive iDCs. Whereas DCs presented in the tumor stroma were exclusively CD208-positive mDCs, CD208-positive mDCs were particularly dense in the margin of cancerous lesions and formed clusters with CD3-positive lymphocytes. The number of CD208-positive mDCs in the tumor mass was significantly lower than the number of CD1alpha-positive iDCs. The current results suggest that ESCC tissue comprises a high frequency of iDCs in the cancerous epithelium and a low density of mDCs in the tumor stroma. Such a distinct distribution pattern may reflect the ongoing DC tracking in ESCCs.

Cytokine adjuvanation of therapeutic anti-tumor immunity targeted to cancer mucosa antigens

Colorectal cancer immunotherapy is limited by the paucity of available target antigens fulfilling the necessary criteria of tumor-specificity, sufficient immunogenicity and universal association with disease. A novel class of immune targets, cancer mucosa antigens (CMAs), whose expression normally is confined to mucosae but maintained during neoplastic transformation, promises to overcome these imitations, enjoying the advantage of immune compartmentalization, preventing autoimmune disease, while permitting therapeutic anti-tumor responses. Indeed, therapeutic immunization against the model CMA guanylyl cyclase c (GCC) extends survival in mouse models of established parenchymal colorectal cancer metastases with antitumor efficacy superior to currently available antigens. Here adjuvanation of therapeutic antitumor immunity to GCC was explored employing the cytokines IL-2 and GM-CSF in a mouse model of metastatic colorectal cancer. Combining plasmids expressing murine IL-2 or GM-CSF with recombinant viral vector immunization to GCC enhanced antitumor efficacy beyond viral vector immunization alone. These studies support the incorporation of IL-2 and GM-CSF in CMA-targeted immunization regimens for established colorectal cancer metastases.

A review of the most promising biomarkers in colorectal cancer: one step closer to targeted therapy

Rapidly growing insights into the molecular biology of colorectal cancer (CRC) and recent developments in gene sequencing and molecular diagnostics have led to high expectations for the identification of molecular markers to be used in optimized and tailored treatment regimens. However, many of the published data on molecular biomarkers are contradictory in their findings and the current reality is that no molecular marker, other than the KRAS gene in the case of epidermal growth factor receptor (EGFR)- targeted therapy for metastatic disease, has made it into clinical practice. Many markers investigated suffer from technical shortcomings, resulting from lack of quantitative techniques to capture the impact of the molecular alteration. This understanding has recently led to the more comprehensive approaches of global gene expression profiling or genome-wide analysis to determine prognostic and predictive signatures in tumors. In this review, an update of the most recent data on promising biological prognostic and/or predictive markers, including microsatellite instability, epidermal growth factor receptor, KRAS, BRAF, CpG island methylator phenotype, cytotoxic T lymphocytes, forkhead box P3-positive T cells, receptor for hyaluronic acid-mediated motility, phosphatase and tensin homolog, and T-cell originated protein kinase, in patients with CRC is provided.

Tumor infiltrating lymphocytes: an intriguing player in the survival of colorectal cancer patients

Background

There is growing evidence that both local and systemic inflammatory responses play an important role in the progression of a variety of solid tumors. Colorectal cancer results from the cumulative effect of sequential genetic alterations, leading to the expression of tumor associated antigens possibly inducing a cellular anti-tumor immune response. It is well recognized that cytotoxic lymphocytes constitute one of the most important effector mechanisms of anti-tumor-immunity. However, their potential prognostic influence in colorectal cancer remains controversial. Aim of the study was to examine infiltration of CD3⁺ and CD8⁺ lymphocytes in colorectal cancer and their prognostic potential.

Two-hundred-fifteen colorectal cancer cases, previously analyzed for microsatellite instability (MSI), were selected for immunohistochemical detection of CD3⁺, CD8⁺ infiltration and the expression of granzyme B. Prognostic relevance was assessed by survival analysis.

Results

Strong correlations were found between the infiltration of lymphocytes and several clinicopathological variables. Survival analysis revealed that intra-epithelial infiltration of CD3⁺ and CD8⁺ T lymphocytes and stromal infiltration of CD3⁺ lymphocytes had a major impact on the patients' overall survival in the univariate analysis, however independent of their association with MSI-status. In addition, it was also demonstrated that there was an important disease specific survival advantage for patients with microsatellite stable (MSS) tumors containing intraepithelial CD8⁺ tumor infiltrating lymphocytes. When samples were analyzed for colon cancer and rectal cancer separately, the results of the overall population were confirmed in colon cancer only. When entered into a multiple Cox regression analysis adjusting for other possible important confounding factors, the strong impact of lymphocyte infiltration on overall survival was not maintained. Only early stage and young age (borderline significant for overall population only) were associated with a better overall survival (early disease with disease-free survival also).

Conclusions

In conclusion our results suggest a role for infiltrating CD3⁺ and CD8⁺ T lymphocytes in colorectal cancer whereby tumor infiltration could reflect a general principle of antitumor immunity, irrespective of the MSI-status.

Data integration and exploration for the identification of molecular mechanisms in tumor-immune cells interaction

Cancer progression is a complex process involving host-tumor interactions by multiple molecular and cellular factors of the tumor microenvironment. Tumor cells that challenge immune activity may be vulnerable to immune destruction. To address this question we have directed major efforts towards data integration and developed and installed a database for cancer immunology with more than 1700 patients and associated clinical data and biomolecular data. Mining of the database revealed novel insights into the molecular mechanisms of tumor-immune cell interaction. In this paper we present the computational tools used to analyze integrated clinical and biomolecular data. Specifically, we describe a database for heterogeneous data types, the interfacing bioinformatics and statistical tools including clustering methods, survival analysis, as well as visualization methods. Additionally, we discuss generic issues relevant to the integration of clinical and biomolecular data, as well as recent developments in integrative data analyses including biomolecular network reconstruction and mathematical modeling.

Immune infiltration in human cancer: prognostic significance and disease control

The interplay between tumors and their immunologic microenvironment is complex and difficult to decipher, but its understanding is of seminal importance for the development of novel prognostic markers and therapeutic strategies. This chapter discusses tumor-immune interactions in several human cancers that illustrate various aspects of this complexity and proposes an integrated scheme of the impact of local immune reactions on clinical outcome. Thus, the fact that a strong infiltration of memory T cells with a Th1 and cytotoxic pattern is the strongest predictor for recurrence and metastasis is exemplified in colorectal cancer in which intratumoral chemokines shape an efficient immune reaction. Based on these data, we propose an immune score that predicts recurrence in early stage (UICC-TNM stage I-II) cancers. Studies on non-small lung cancers have confirmed findings of colorectal cancers and have addressed the question of the sites where antitumor immune reactions may take place. Tertiary lymphoid structures (TLS) adjacent to the tumor nest are sites of intense activity with mature dendritic cells in contact with T cells and germinal-like centers with proliferating B cells. The large number of these TLS being correlated with disease specific and overall survival tempts to postulate that they are privileged sites to mount an efficient antitumor reaction. Inflammation is a major component of human tumors and chronic inflammation is generally of bad prognosis. Head and neck cancers are highly inflammatory and two ways to modulate inflammation in these diseases are presented here: soluble IL-15 receptor α (IL-15 Rα) increases the pro-inflammatory effect of IL-15 and aggravates inflammation resulting in poor prognosis when found at high levels in the plasma of patients. By contrast, infiltration of regulatory T cells is paradoxically beneficial for local control of head and neck tumors, probably by "cooling down" the inflammatory process. The modulation of other aspects of innate immunity may also result in paradoxical effects such as the signaling through Toll like receptors 7 and 8 expressed on lung tumor cells which induce an aggressive tumoral phenotype. Finally, the analysis of primary intraocular lymphoma, which develops in the eye, exemplifies the induction of an antitumor immune reaction in an "immune sanctuary," presenting all the complexities of the tumor-immune interplay in "open" tissues such as the colon or the lung.

Immune infiltration in human tumors: a prognostic factor that should not be ignored

The natural history of a tumor includes phases of 'in situ' growth, invasion, extravasation and metastasis. During these phases, tumor cells interact with their microenvironment and are influenced by signals coming from stromal, endothelial, inflammatory and immune cells. Indeed, tumors are often infiltrated by various numbers of lymphocytes, macrophages or mast cells. It is generally believed that the latter produce factors that maintain chronic inflammation and promote tumor growth, whereas lymphocytes may control cancer outcome, as evidenced in mouse models. In this study, we analyze data from large cohorts of human tumors, clearly establishing that infiltration of the primary tumor by memory T cells, particularly of the Th1 and cytotoxic types, is the strongest prognostic factor in terms of freedom from disease and overall survival at all stages of clinical disease. We review data suggesting that tertiary lymphoid structures adjacent to tumors and composed of mature dendritic cells (T and B cells organized as germinal centers) may be the site of an antitumor reaction. We propose an immune scoring based on the type, density and location of lymphocyte infiltrates as a novel prognostic factor for use in addition to tumor node metastasis staging to predict disease-free survival and to aid in decisions regarding adjuvant therapies in early stage human cancers.

Lineage-specific T-cell responses to cancer mucosa antigen oppose systemic metastases without mucosal inflammatory disease

Cancer mucosa antigens are emerging as a new category of self-antigens expressed normally in immunologically privileged mucosal compartments and universally by their derivative tumors. These antigens leverage the established immunologic partitioning of systemic and mucosal compartments, limiting tolerance opposing systemic antitumor efficacy. An unresolved issue surrounding self-antigens as immunotherapeutic targets is autoimmunity following systemic immunization. In the context of cancer mucosa antigens, immune effectors to self-antigens risk amplifying mucosal inflammatory disease promoting carcinogenesis. Here, we examined the relationship between immunotherapy for systemic colon cancer metastases targeting the intestinal cancer mucosa antigen guanylyl cyclase C (GCC) and its effect on inflammatory bowel disease and carcinogenesis in mice. Immunization with GCC-expressing viral vectors opposed nascent tumor growth in mouse models of pulmonary metastasis, reflecting systemic lineage-specific tolerance characterized by CD8(+), but not CD4(+), T-cell or antibody responses. Responses protecting against systemic metastases spared intestinal epithelium from autoimmunity, and systemic GCC immunity did not amplify chemically induced inflammatory bowel disease. Moreover, GCC immunization failed to promote intestinal carcinogenesis induced by germ-line mutations or chronic inflammation. The established role of CD8(+) T cells in antitumor efficacy, but CD4(+) T cells in autoimmunity, suggests that lineage-specific responses to GCC are particularly advantageous to protect against systemic metastases without mucosal inflammation. These observations support the utility of GCC-targeted immunotherapy in patients at risk for systemic metastases, including those with inflammatory bowel disease, hereditary colorectal cancer syndromes, and sporadic colorectal cancer.

Induction of type 1 cytokines during neem leaf glycoprotein assisted carcinoembryonic antigen vaccination is associated with nitric oxide production

Involvement of the nitric oxide (NO) release in CEAM phi NLGP (carcinoembryonic antigen pulsed macrophages with neem leaf glycoprotein) vaccination and its relationship with vaccine induced type 1 immune response were aimed to study in the present communication. Vaccination with CEAM phi NLGP resulted in macrophage activation as evidenced by its increased number and expression of CD69 marker. Activated macrophages demonstrated upregulation in synthesis of IL-12 and downregulation in IL-10, along with excess IFN gamma production in splenic cells, as evidenced from mRNA analysis. Induction of such type 1 immunity was further confirmed by expression of type 1 specific transcription factor, T-bet and enhancement of intracellular glutathione content. Such vaccination also induced greater nitric oxide (NO) production from macrophages. Dependence of induced type 1 immune response on the NO release and vice versa was studied by in vitro neutralization of IFN gamma/IL-12 and in vivo inhibition of NO production by methylene blue. Obtained results clearly demonstrated the interdependence of two anti-tumor immune functions, namely, NO production and generation of type 1 immune response. Understanding of the mechanism of this NO related immune modulation would have great impact in proposing CEAM phi NLGP vaccine in clinic for the treatment of CEA+ tumors.