CD4 regulatory T cells in human cancer pathogenesis

Clinical and immunological characteristics of high-risk double-hit multiple myeloma

At present, the characteristics of double-hit multiple myeloma (DHMM) are unknown. We retrospectively analyzed the clinical data from 433 new diagnosed MM patients and found that DHMM have a higher β2-MG level and percentage of bone marrow plasma cell. Cox regression analysis showed that the prognosis of DHMM was not limited by clinical indicators. The abnormal proliferation of bone marrow in DHMM is obvious, and the proportion of poorly differentiated plasma cell is high. By collecting specimens from our center and performing flow cytometry to analyze the immunophenotypic and functional characteristics of lymphocyte subpopulations, we found that DHMM had a higher ratio of Tregs cells, and the proportion of iTregs cells was also significantly higher than non-DHMM (P < 0.05). Moreover, DHMM had higher levels of TGF-β1 and IL-10, and TGF-β1 and IL-10 were positively correlated with iTregs (P < 0.05). In addition, DHMM was highly expressed PD-1 on CD8 + T cells and had a higher proportion of CD38highTregs cells. In vitro we have shown that the addition of TGF-β1 antibody or CD38 antibody can effectively inhibit the proportion of CD38high Tregs. This study describes the characteristics of DHMM based on bicentric data, which is helpful to better provide theoretical support for the treatment of DHMM.

Immune mediated support of metastasis: Implication for bone invasion

Bone is a common organ affected by metastasis in various advanced cancers, including lung, breast, prostate, colorectal, and melanoma. Once a patient is diagnosed with bone metastasis, the patient's quality of life and overall survival are significantly reduced owing to a wide range of morbidities and the increasing difficulty of treatment. Many studies have shown that bone metastasis is closely related to bone microenvironment, especially bone immune microenvironment. However, the effects of various immune cells in the bone microenvironment on bone metastasis remain unclear. Here, we described the changes in various immune cells during bone metastasis and discussed their related mechanisms. Osteoblasts, adipocytes, and other non-immune cells closely related to bone metastasis were also included. This review also summarized the existing treatment methods and potential therapeutic targets, and provided insights for future studies of cancer bone metastasis.

What happens to regulatory T cells in multiple myeloma

Abnormal tumor microenvironment and immune escape in multiple myeloma (MM) are associated with regulatory T cells (Tregs), which play an important role in maintaining self-tolerance and regulating the overall immune response to infection or tumor cells. In patients with MM, there are abnormalities in the number, function and distribution of Tregs, and these abnormalities may be related to the disease stage, risk grade and prognosis of patients. During the treatment, Tregs have different responses to various treatment regiments, thus affecting the therapeutic effect of MM. It is also possible to predict the therapeutic response by observing the changes of Tregs. In addition to the above, we reviewed the application of Tregs in the treatment of MM. In conclusion, there is still much room for research on the mechanism and application of Tregs in MM.

Immune checkpoint analysis in ear cancer

BACKGROUND

Among cutaneous squamous cell carcinomas, the ear (ecSCC) is one of the most common sites. Loco regional lymph node metastasis is found in six to eleven percent of cases, corresponding to increased metastasis compared to other sites. The aim of this study was to test the markers PD-L1, PD-1, CD4, CD8, and FoxP3 for suitability as prognostic predictive markers.

METHODS

Sixty-four patients with ecSCC were included in this study. The expression of immunohistochemical markers (PD-L1, PD-1, CD4, CD8, FOXP3) was correlated with retrospective clinic pathological parameters (lymph node metastasis, distant metastasis, lymph node metastasis during follow-up, disease progression, disease-specific death).

RESULTS

There was a correlation between increased disease specific death and a weak Foxp3 (p = 0.003) or reduced CD8 (p = 0.04). A PD-L1 expression > 1% was found in 39.1% of patients.

CONCLUSION

The investigated markers (CD4, CD8, FoxP3, PD-1, PD-L1) seem overall rather inappropriate for prognostic evaluation in ecSCC. Only the correlation of disease specific death with CD8 or FoxP3 seems to be worth testing in larger collectives.

Effects of pre-operative biopsy on recurrence and survival in stage I lung adenocarcinoma patients in China

Background

Whether pre-operative biopsy affects post-operative recurrence and metastasis of lung cancer patients is still controversial.

Methods

In order to clarify these disputes, we collected relevant literature to conduct a meta-analysis. To validate the results of the meta-analysis, we retrospectively analysed 575 patients with stage I lung adenocarcinoma who underwent surgical resection at our centre from 2010 to 2018 using propensity score matching and competing risk models.

Results

5509 lung cancer patients from 11 articles were included in the meta-analysis. Summary analysis showed that the total recurrence rate of the biopsy group was higher than that of the nonbiopsy group (risk ratio 1.690, 95% CI 1.220-2.330; p=0.001). After propensity score matching, we found that there was no significant correlation between biopsy and total recurrence (risk ratio 1.070, 95% CI 0.540-2.120; p=0.850). In our cohort, of 575 stage I lung adenocarcinomas, 113 (19.7%) patients underwent pre-operative biopsy. During a median (interquartile range) follow-up of 71 (57-93) months, multivariable analyses showed pre-operative biopsy in the overall observation cohort (subdistribution hazard ratio (SHR) 1.522, 95% CI 0.997-2.320; p=0.051) and in the propensity score-matched cohort (SHR 1.134, 95% CI 0.709-1.810; p=0.600) was not significantly correlated with the risk of recurrence and metastasis. Moreover, the pre-operative biopsy did not affect disease-free survival (SHR 0.853, 95% CI 0.572-1.273; p=0.438) or overall survival (SHR 0.647, 95% CI 0.352-1.189; p=0.161).

Conclusion

Pre-operative biopsy might not increase the risk of recurrence and metastasis, suggesting that these procedures might be safe for patients with stage I lung adenocarcinoma whose diagnosis is difficult to determine before surgery.

Oncogenic Viruses-Encoded microRNAs and Their Role in the Progression of Cancer: Emerging Targets for Antiviral and Anticancer Therapies

Approximately 20% of all cases of human cancer are caused by viral infections. Although a great number of viruses are capable of causing a wide range of tumors in animals, only seven of these viruses have been linked to human malignancies and are presently classified as oncogenic viruses. These include the Epstein-Barr virus (EBV), human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), Merkel cell polyomavirus (MCPyV), human herpesvirus 8 (HHV8), and human T-cell lymphotropic virus type 1 (HTLV-1). Some other viruses, such as the human immunodeficiency virus (HIV), are associated with highly oncogenic activities. It is possible that virally encoded microRNAs (miRNAs), which are ideal non-immunogenic tools for viruses, play a significant role in carcinogenic processes. Both virus-derived microRNAs (v-miRNAs) and host-derived microRNAs (host miRNAs) can influence the expression of various host-derived and virus-derived genes. The current literature review begins with an explanation of how viral infections might exert their oncogenic properties in human neoplasms, and then goes on to discuss the impact of diverse viral infections on the advancement of several types of malignancies via the expression of v-miRNAs. Finally, the role of new anti-oncoviral therapies that could target these neoplasms is discussed.

Proteomics analysis uncovers plasminogen activator PLAU as a target of the STING pathway for suppression of cancer cell migration and invasion

The stimulator of interferon genes (STING) pathway is vital for immune defense against pathogen invasion and cancer. Although ample evidence substantiates that the STING signaling pathway plays an essential role in various cancers via cytokines, no comprehensive investigation of secretory proteins regulated by the STING pathway has been conducted hitherto. Herein, we identify 24 secretory proteins significantly regulated by the STING signaling pathway through quantitative proteomics. Mechanistic analyses reveal that STING activation inhibits the translation of urokinase-type plasminogen activator (PLAU) via the STING-PERK-eIF2α signaling axis. PLAU is highly expressed in a variety of cancers and promotes the migration and invasion of cancer cells. Notably, the activation of STING inhibits cancer cell migration and invasion by suppressing PLAU. Collectively, these results provide novel insights into the anticancer mechanism of the STING pathway, offering a theoretical basis for precision therapy for this patient population.

Correlation and prognostic implications of intratumor and tumor draining lymph node Foxp3+ T regulatory cells in colorectal cancer

BACKGROUND

The prognostic value of intratumor T regulatory cells (Tregs) in colorectal cancer (CRC) was previously reported, but the role of these cells in tumor draining lymph nodes (TDLNs) was less addressed.

METHODS

A total of 150 CRC stages I-IV were retrospectively enrolled. Intratumor and TDLN Tregs were examined by immunohistochemical assay. The association of these cells was estimated by Pearson correlation. Survival analyses of subgroups were conducted by Kaplan-Meier curves, and the log-rank test and risk factors for survival were tested by the Cox proportional hazard model.

RESULTS

High accumulation of Tregs in tumors was significant in patients with younger age and good histological grade, where enrichment of these cells in TDLNs was more apparent in those with node-negative disease and early TNM stage disease, both of which were more common in early T stage cases. A significant correlation of intratumoral and TDLN Tregs was detected. Patients with higher intratumoral Tregs displayed significantly better PFS and OS than those with lower Tregs. However, no such differences were found, but a similar prognostic prediction trend was found for these cells in TDLNs. Finally, intratumoral Tregs were an independent prognostic factor for both PFS (HR = 0.97, 95% CI 0.95-0.99, P < 0.01) and OS (HR = 0.98, 95% CI 0.95-1.00, P = 0.04) in the patients.

CONCLUSIONS

Higher intratumor Tregs were associated with better survival in CRC. Although no such role was found for these cells in TDLNs, the positive correlation and similar prognostic prediction trend with their intratumoral counterparts may indicate a parallelized function of these cells in CRC.

Annexin A1 as a Regulator of Immune Response in Cancer

Annexin A1 is a 37 kDa phospholipid-binding protein that is expressed in many tissues and cell types, including leukocytes, lymphocytes and epithelial cells. Although Annexin A1 has been extensively studied for its anti-inflammatory activity, it has been shown that, in the cancer context, its activity switches from anti-inflammatory to pro-inflammatory. Remarkably, Annexin A1 shows pro-invasive and pro-tumoral properties in several cancers either by eliciting autocrine signaling in cancer cells or by inducing a favorable tumor microenvironment. Indeed, the signaling of the N-terminal peptide of AnxA1 has been described to promote the switching of macrophages to the pro-tumoral M2 phenotype. Moreover, AnxA1 has been described to prevent the induction of antigen-specific cytotoxic T cell response and to play an essential role in the induction of regulatory T lymphocytes. In this way, Annexin A1 inhibits the anti-tumor immunity and supports the formation of an immunosuppressed tumor microenvironment that promotes tumor growth and metastasis. For these reasons, in this review we aim to describe the role of Annexin A1 in the establishment of the tumor microenvironment, focusing on the immunosuppressive and immunomodulatory activities of Annexin A1 and on its interaction with the epidermal growth factor receptor.

Immunophenotype of Vestibular Schwannomas

BACKGROUND

Vestibular schwannomas exhibit a uniquely variable natural history of growth, stability, or even spontaneous regression. We hypothesized that a transitory population of immune cells, or immunomodulation of tumors cells, may influence the growth pattern of schwannomas. We therefore sought to characterize the impact of the immune microenvironment on schwannoma behavior.

METHODS

Forty-eight vestibular schwannomas with preoperative magnetic resonance imaging and 11 with serial imaging were evaluated for presence of immune infiltrates (including the pan-leukocyte marker Cluster of Differentiation (CD)45, CD4 and CD8 T-cell, and CD68 and CD163 macrophages) as well as expression of immunomodulatory regulators (Programmed Death Ligand 1 (PD-L1), Programmed Death Ligand 2 (PD-L2), LAG-3, TIM-3, V-domain Ig Suppressor of T cell Activation). Maximal diameter, volume, and recurrence were annotated.

RESULTS

Vestibular schwannomas were characterized by diverse signatures of tumor infiltrating leukocytes and immunomodulatory markers. The median tumor volume was 4.7 cm (Interquartile Range (IQR) 1.0-13.0) and maximum diameter was 2.3 cm (IQR 1.5-3.2). Among tumors with serial imaging, the median volumetric growth was 0.04 cm/mo (IQR 0.01-0.18). Tumor volume and maximum diameter demonstrated strong concordance (R = 0.90; p < 0.001). Vestibular schwannoma volume was positively associated with CD4, CD68, and CD163, but not CD8, immune infiltration (all p < 0.05). Tumor growth was positively associated with CD163 and PD-L1 (both p < 0.05). Further, CD163 modified this effect: the relationship between PD-L1 and growth strengthened with increasing CD163 infiltration (R = 0.81, p = 0.007). No other immune cell types modified this relationship. These associations were inconsistently observed for maximum diameter and linear growth.

CONCLUSION

Vestibular schwannomas demonstrate variable expression of immune regulatory markers as well as immune infiltrates. Tumor size is associated with immune infiltrates and tumor growth is associated with PD-L1, especially in the presence of M2-subtype macrophages. Volumetric measures may associate with the biological signature more accurately than linear parameters. Future exploration of the role of immune modulation in select schwannomas will further enhance our understanding of the biology of these tumors and suggest potential therapeutic avenues for control of tumor growth.

Immunological Prognostic Factors in Multiple Myeloma

Multiple myeloma (MM) is a plasma cell neoplasm characterized by an abnormal proliferation of clonal, terminally differentiated B lymphocytes. Current approaches for the treatment of MM focus on developing new diagnostic techniques; however, the search for prognostic markers is also crucial. This enables the classification of patients into risk groups and, thus, the selection of the most optimal treatment method. Particular attention should be paid to the possible use of immune factors, as the immune system plays a key role in the formation and course of MM. In this review, we focus on characterizing the components of the immune system that are of prognostic value in MM patients, in order to facilitate the development of new diagnostic and therapeutic directions.

The role of regulatory T cells in the pathogenesis and treatment of prostate cancer

Despite developments in the treatment of various cancers, prostate cancer is one of the deadliest diseases known to men. Systemic therapies such as androgen deprivation, chemotherapy, and radiation therapy have not been very successful in treating this disease. Numerous studies have shown that there is a direct relationship between cancer progression and inhibition of anti-tumor immune responses that can lead to progression of various malignancies, including prostate cancer. Interestingly, CD4⁺CD25⁺FoxP3⁺ regulatory T cells significantly accumulate and increase in draining lymph nodes and PBMCs of patients with prostate cancer and other solid tumors. In vivo and in vitro studies have shown that Tregs can suppress anti-tumor responses, which is directly related to the increased risk of cancer recurrence. Tregs are essential for preserving self-tolerance and inhibiting extra immune responses harmful to the host. Since the tumor-related antigens are mainly self-antigens, Tregs could play a major role in tumor progression. Accordingly, it has discovered that prostate cancer patients with higher Tregs have poor prognosis and low survival rates. However, anti-tumor responses can be reinforced by suppression of Tregs with using monoclonal antibodies against CD25 and CTLA-4. Therefore, depleting Tregs or suppressing their functions could be one of the effective ways for prostate cancer immunotherapy. The purpose of this review is to investigate the role of Treg cells in the progression of prostate cancer and to evaluate effective strategies for the treatment of prostate cancer by regulating Treg cells.

T-Regulatory Cells In Tumor Progression And Therapy

Regulatory T cells (Tregs) are important members of the immune system regulating the host responses to infection and neoplasms. Tregs prevent autoimmune disorders by protecting the host-cells from an immune response, related to the peripheral tolerance. However, tumor cells use Tregs as a shield to protect themselves against anti-tumor immune response. Thus, Tregs are a hurdle in achieving the complete potential of anti-cancer therapies including immunotherapy. This has prompted the development of novel adjuvant therapies that obviate their negative effects thereby enhancing the therapeutic efficacy. Our earlier studies have shown the efficacy of the glycolytic inhibitor, 2-deoxy-D-glucose (2-DG) by reducing the induced Tregs pool and enhance immune stimulation as well as local tumor control. These findings have suggested its potential for enhancing the efficacy of immunotherapy, besides radiotherapy and chemotherapy. This review provides a brief account of the current status of Tregs as a component of the immune-biology of tumors and various preclinical and clinical strategies pursued to obviate the limitations imposed by them in achieving therapeutic efficacy.

APRIL signaling via TACI mediates immunosuppression by T regulatory cells in multiple myeloma: therapeutic implications

We here investigate how APRIL impacts immune regulatory T cells and directly contributes to the immunosuppressive multiple myeloma (MM) bone marrow (BM) microenvironment. First, APRIL receptor TACI expression is significantly higher in regulatory T cells (Tregs) than conventional T cells (Tcons) from the same patient, confirmed by upregulated Treg markers, i.e., Foxp3, CTLA-4. APRIL significantly stimulates proliferation and survival of Tregs, whereas neutralizing anti-APRIL monoclonal antibodies (mAbs) inhibit theses effects. Besides TACI-dependent induction of cell cycle progression and anti-apoptosis genes, APRIL specifically augments Foxp3, IL-10, TGFβ1, and PD-L1 in Tregs to further enhance Treg-inhibited Tcon proliferation. APRIL further increases MM cell-driven Treg (iTreg) via TACI-dependent proliferation associated with upregulated IL-10, TGFβ1, and CD15s in iTreg, which further inhibits Tcons. Osteoclasts producing APRIL and PD-L1 significantly block Tcon expansion by iTreg generation, which is overcome by combined treatment with anti-APRIL and -PD1/PD-L1 mAbs. Finally, APRIL increases IL-10-producing B regulatory cells (Bregs) via TACI on BM Bregs of MM patients. Taken together, these results define novel APRIL actions via TACI on Tregs and Bregs to promote MM cell survival, providing the rationale for targeting APRIL/TACI system to alleviate the immunosuppressive BM milieu and improve patient outcome in MM.

Melatonin and Hippo Pathway: Is There Existing Cross-Talk?

Melatonin is an indolic hormone that regulates a plethora of functions ranging from the regulation of circadian rhythms and antioxidant properties to the induction and maintenance of tumor suppressor pathways. It binds to specific receptors as well as to some cytosolic proteins, leading to several cellular signaling cascades. Recently, the involvement of melatonin in cancer insurgence and progression has clearly been demonstrated. In this review, we will first describe the structure and functions of melatonin and its receptors, and then discuss both molecular and epidemiological evidence on melatonin anticancer effects. Finally, we will shed light on potential cross-talk between melatonin signaling and the Hippo signaling pathway, along with the possible implications for cancer therapy.

Patient-derived xenograft (PDX) models in basic and translational breast cancer research

Patient-derived xenograft (PDX) models of a growing spectrum of cancers are rapidly supplanting long-established traditional cell lines as preferred models for conducting basic and translational preclinical research. In breast cancer, to complement the now curated collection of approximately 45 long-established human breast cancer cell lines, a newly formed consortium of academic laboratories, currently from Europe, Australia, and North America, herein summarizes data on over 500 stably transplantable PDX models representing all three clinical subtypes of breast cancer (ER+, HER2+, and "Triple-negative" (TNBC)). Many of these models are well-characterized with respect to genomic, transcriptomic, and proteomic features, metastatic behavior, and treatment response to a variety of standard-of-care and experimental therapeutics. These stably transplantable PDX lines are generally available for dissemination to laboratories conducting translational research, and contact information for each collection is provided. This review summarizes current experiences related to PDX generation across participating groups, efforts to develop data standards for annotation and dissemination of patient clinical information that does not compromise patient privacy, efforts to develop complementary data standards for annotation of PDX characteristics and biology, and progress toward "credentialing" of PDX models as surrogates to represent individual patients for use in preclinical and co-clinical translational research. In addition, this review highlights important unresolved questions, as well as current limitations, that have hampered more efficient generation of PDX lines and more rapid adoption of PDX use in translational breast cancer research.

Immunotherapy of advanced renal cell carcinoma: Current and future therapies

Previously a malignancy with few therapeutic options, metastatic renal cell carcinoma (mRCC) treatment is rapidly evolving. Although cytokine therapies (interferon-a, interleukin-2) have been used less frequently over the past decade, recent approval of an immune checkpoint inhibitor, nivolumab, has led to a resurgence in immune therapy for mRCC. With greater understanding of the complex and dynamic interaction between the tumor and the immune system, numerous new immunotherapies are being studied for mRCC. In this article, we review the mechanism of action, clinical outcomes and toxicity profiles of both clinically approved and selected investigational immunotherapies. Either alone or in combination, these novel agents are encouraging for the future of mRCC therapy.

Circulating Tumor Cells (CTC) Are Associated with Defects in Adaptive Immunity in Patients with Inflammatory Breast Cancer

Background: Circulating tumor cells (CTCs) play a crucial role in tumor dissemination and are prognostic in primary and metastatic breast cancer. Peripheral blood (PB) immune cells contribute to an unfavorable microenvironment for CTC survival. This study aimed to correlate CTCs with the PB T-cell immunophenotypes and functions of patients with inflammatory breast cancer (IBC).

Methods: This study included 65 IBC patients treated at the MD Anderson Cancer Center. PB was obtained from patients prior to starting a new line of chemotherapy for CTCs enumeration by CellSearch^®, and T cell phenotype and function by flow cytometry; the results were correlated with CTCs and clinical outcome.

Results: At least 1 CTC (≥1) or ≥5 CTCs was detected in 61.5% or 32.3% of patients, respectively. CTC count did not correlate with total lymphocytes; however, patients with ≥1 CTC or ≥5 CTCs had lower percentages (%) of CD3+ and CD4+ T cells compared with patients with no CTCs or <5 CTCs, respectively. Patients with ≥1 CTC had a lower percentage of T-cell receptor (TCR)-activated CD8+ T cells synthesizing TNF-α and IFN-γ and a higher percentage of T-regulatory lymphocytes compared to patients without CTCs. In multivariate analysis, tumor grade and % CD3+ T-cells were associated with ≥1 CTC, whereas ≥5 CTC was associated with tumor grade, stage, % CD3+ and % CD4+ T cells, and % TCR-activated CD8 T-cells synthesizing IL-17.

Conclusions: IBC patients with CTCs in PB had abnormalities in adaptive immunity that could potentially impact tumor cell dissemination and initiation of the metastatic cascade.

Magnitude of PD-1, PD-L1 and T Lymphocyte Expression on Tissue from Castration-Resistant Prostate Adenocarcinoma: An Exploratory Analysis

BACKGROUND AND AIM

Recent therapeutic strategies for castration-resistant prostate cancer have focused on immunomodulation, especially the PD-1/PD-L1 pathway related to tumor-infiltrating lymphocytes. Few cases of castration-resistant prostate adenocarcinoma have been tested simultaneously for PD-1, PD-L1 and T lymphocytes in cancerous tissue. We quantified the PD-1/PD-L1 immune pathway and T lymphocyte infiltrates in a series of patients with castrate-resistant prostate adenocarcinoma.

PATIENTS AND METHODS

Expression of PD-1, PD-L1, CD3 and FOXP3 was identified in tissue microarrays, with five tissue spots per patient from 16 patients over at least 5 years of follow-up. Two scores were defined. The first described the percentage of PD-1-positive T lymphocytes (CD3+): negative (0), <5 %; low (1+), 5-30 %; high (2+), >30 %. The second described PD-L1 staining intensity: 0 (no signal), 1+ (light signal), 2+ (high signal) in >50 % of neoplastic cells.

RESULTS

Tumor-infiltrating T lymphocytes (CD3+) were seen in 11/16 cases (69 %). Nine of 16 cases expressed PD-1 (56 %), among which 19 % were scored 2+. Eight of 16 cases expressed PD-L1 (50 %), with 19 % scored as strong 2+. The subgroup with high PD1/PD-L1 also exhibited FOXP3 expression.

CONCLUSIONS

Approximately 19 % of patients in our series showed simultaneous high PD-1/PD-L1 immunoscores, and were the best candidates for receiving targeted anti-PD-1/PD-L1 immunotherapy, as determined using a tissue based rationale.

Cumulative Doses of T-Cell Depleting Antibody and Cancer Risk after Kidney Transplantation

T-cell depleting antibody is associated with an increased risk of cancer after kidney transplantation, but a dose-dependent relationship has not been established. This study aimed to determine the association between cumulative doses of T-cell depleting antibody and the risk of cancer after kidney transplantation. Using data from the Australian and New Zealand Dialysis and Transplant Registry between 1997–2012, we assessed the risk of incident cancer and cumulative doses of T-cell depleting antibody using adjusted Cox regression models. Of the 503 kidney transplant recipients with 2835 person-years of follow-up, 276 (55%), 209 (41%) and 18 (4%) patients received T-cell depleting antibody for induction, rejection or induction and rejection respectively. The overall cancer incidence rate was 1,118 cancers per 100,000 patient-years, with 975, 1093 and 1377 cancers per 100,000 patient-years among those who had received 1–5 doses, 6–10 doses and >10 doses, respectively. There was no association between cumulative doses of T cell depleting antibody and risk of incident cancer (1–5: referent, 6–10: adjusted hazard ratio (HR) 1.19, 95%CI 0.48–2.95, >10: HR 1.42, 95%CI 0.50–4.02, p = 0.801). This lack of association is contradictory to our hypothesis and is likely attributed to the low event rates resulting in insufficient power to detect significant differences.

Prognostic and predictive significance of immune cells infiltrating cutaneous melanoma

The tumor microenvironment is shaped by interactions between malignant cells and host cells representing an integral component of solid tumors. Host cells, including elements of the innate and adaptive immune system, can exert both positive and negative effects on the outcome of the disease. In melanoma, studies on the prognostic impact of the lymphoid infiltrate in general, and that of T cells, yielded controversial results. According to our studies and data in the literature, a high peritumoral density of activated T cells, increased amount of B lymphocytes and mature dendritic cells (DCs) predicted longer survival, while intense infiltration by plasmacytoid DCs or neutrophil granulocytes could be associated with poor prognosis. Besides its prognostic value, evaluation of the components of immune infiltrate could provide biomarkers for predicting the efficacy of the treatment and disease outcome in patients treated with immunotherapy or other, non-immune-based modalities as chemo-, radio-, or targeted therapy.

Regulatory T cells, inherited variation, and clinical outcome in epithelial ovarian cancer

The immune system constitutes one of the host factors modifying outcomes in ovarian cancer. Regulatory T cells (Tregs) are believed to be a major factor in preventing the immune response from destroying ovarian cancers. Understanding mechanisms that regulate Tregs in the tumor microenvironment could lead to the identification of novel targets aimed at reducing their influence. In this study, we used immunofluorescence-based microscopy to enumerate Tregs, total CD4 T cells, and CD8(+) cytotoxic T cells in fresh frozen tumors from over 400 patients with ovarian cancer (>80 % high-grade serous). We sought to determine whether Tregs were associated with survival and genetic variation in 79 genes known to influence Treg induction, trafficking, or function. We used Cox regression, accounting for known prognostic factors, to estimate hazard ratios (HRs) associated with T cell counts and ratios. We found that the ratios of CD8 T cells and total CD4 T cells to Tregs were associated with improved overall survival (CD8/Treg HR 0.84, p = 0.0089; CD4/Treg HR 0.88, p = 0.046) and with genetic variation in IL-10 (p = 0.0073 and 0.01, respectively). In multivariate analyses, the associations between the ratios and overall survival remained similar (IL-10 and clinical covariate-adjusted CD8/Treg HR 0.85, p = 0.031; CD4/Treg HR 0.87, p = 0.093), suggesting that this association was not driven by variation in IL-10. Thus, integration of novel tumor phenotyping measures with extensive clinical and genetic information suggests that the ratio of T cells to Tregs may be prognostic of outcome in ovarian cancer, regardless of inherited genotype in genes related to Tregs.

Upregulation of CD200 is associated with regulatory T cell expansion and disease progression in multiple myeloma

Immune dysfunction is an important feature of multiple myeloma (MM) leading to infections, enhancement of tumour growth and resistance to chemotherapy. The overexpression of CD200, expansion of T regulatory (Treg) cell and increased levels of immune modulatory cytokines like IL10, IL6 and transforming growth factor beta (TGFβ) were suggested to have a role in this context. The aim of this study was to assess CD200 expression, Treg percentage by flow cytometry and immune modulatory cytokines (IL10, IL6, TGFβ) by enzyme-linked immunosorbent assay in MM patients at diagnosis. This study included 50 MM patients at diagnosis and 20 healthy controls. The positive CD200 expression was detected in 72% of MM patients. Among the CD200 positive group, 4/13 patients (30.8%) were classified as stage I, 18/23 (78.3%) were in stage II and 14/14 (100%) were in stage III; according to International scoring system. Treg percentage was significantly higher in stage III, followed by stage II then stage I (p < 0.01). Serum IL6, IL10 and TGFβ were significantly higher in MM patients as compared with controls (p < 0.01, p < 0.01, p < 0.05, respectively). The increased expression of CD200 and Treg percentages was associated with increased severity biomarkers (serum LDH and β2 microglobulin). The degree of CD200 expression was significantly positively correlated to Treg percentage (r = 0.565, p < 0.01). Analysis of the CD200 negative patients had a better progression free survival (p = 0.032) and overall survival (p = 0.04) as compared with those positive for CD200 expression. These findings illustrate a clear correlation between myeloma cell CD200 expression level and the frequency of immunosuppressive Treg cells. In conclusion, increased expression of CD200, expansion of suppressive Treg cells and elevation of cytokines might have a role in MM progression in this cohort of patients. Copyright © 2015 John Wiley & Sons, Ltd.

Survival with AGS-003, an autologous dendritic cell-based immunotherapy, in combination with sunitinib in unfavorable risk patients with advanced renal cell carcinoma (RCC): Phase 2 study results

BACKGROUND

AGS-003 is an autologous immunotherapy prepared from fully matured and optimized monocyte-derived dendritic cells, which are co-electroporated with amplified tumor RNA plus synthetic CD40L RNA. AGS-003 was evaluated in combination with sunitinib in an open label phase 2 study in intermediate and poor risk, treatment naïve patients with metastatic clear cell renal cell carcinoma (mRCC).

METHODS

Twenty-one intermediate and poor risk patients were treated continuously with sunitinib (4 weeks on, 2 weeks off per 6 week cycle). After completion of the first cycle of sunitinib, patients were treated with AGS-003 every 3 weeks for 5 doses, then every 12 weeks until progression or end of study. The primary endpoint was to determine the complete response rate. Secondary endpoints included clinical benefit, safety, progression free survival (PFS) and overall survival (OS). Immunologic response was also monitored.

RESULTS

Thirteen patients (62%) experienced clinical benefit (9 partial responses, 4 with stable disease); however there were no complete responses in this group of intermediate and poor risk mRCC patients and enrollment was terminated early. Median PFS from registration was 11.2 months (95% CI 6.0, 19.4) and the median OS from registration was 30.2 months (95% CI 9.4, 57.1) for all patients. Seven (33%) patients survived for at least 4.5 years, while five (24%) survived for more than 5 years, including 2 patients who remain progression-free with durable responses for more than 5 years at the time of this report. AGS-003 was well tolerated with only mild injection-site reactions. The most common adverse events were related to expected toxicity from sunitinib therapy. In patients who had sequential samples available for immune monitoring, the magnitude of the increase in the absolute number of CD8(+) CD28(+) CD45RA(-) effector/memory T cells (CTLs) after 5 doses of AGS-003 relative to baseline, correlated with overall survival.

CONCLUSIONS

AGS-003 in combination with sunitinib was well tolerated and yielded supportive immunologic responses coupled with extension of median and long-term survival in an unselected, intermediate and poor risk prognosis mRCC population.

CLINICAL TRIAL REGISTRY

#NCT00678119.

Targeted immune therapy of ovarian cancer

Clinical outcomes, such as recurrence-free survival and overall survival, in ovarian cancer are quite variable, independent of common characteristics such as stage, response to therapy, and grade. This disparity in outcomes warrants further exploration and therapeutic targeting into the interaction between the tumor and host. One compelling host characteristic that contributes both to the initiation and progression of ovarian cancer is the immune system. Hundreds of studies have confirmed a prominent role for the immune system in modifying the clinical course of the disease. Recent studies also show that anti-tumor immunity is often negated by immune regulatory cells present in the tumor microenvironment. Regulatory immune cells also directly enhance the pathogenesis through the release of various cytokines and chemokines, which together form an integrated pathological network. Thus, in the future, research into immunotherapy targeting ovarian cancer will probably become increasingly focused on combination approaches that simultaneously augment immunity while preventing local immune suppression. In this article, we summarize important immunological targets that influence ovarian cancer outcome as well as include an update on newer immunotherapeutic strategies.

Clinical relevance of regulatory T cells monitoring in the peripheral blood of ovarian cancer patients

BACKGROUND

Tregs play a suppressive role in the control of antitumour immunity. In this study we evaluated the relevance of prospective monitoring of peripheral blood regulatory T cells (Tregs) as a potential prognostic marker of future outcome of epithelial ovarian cancer in patients with or without a metronomic chemotherapy.

METHODS

46 patients diagnosed with the ovarian cancer were enrolled in the study and divided into groups according to the stage of the disease, outcome of the surgery and treatment received. Proportions of Tregs in the peripheral blood samples were evaluated using flow cytometry.

RESULTS

We show that the early stage of the disease and absence of the tumor residuum after radical surgery are the most important factors predicting a favourable clinical outcome in the ovarian cancer. We did not show any significant effect of consolidation chemotherapy with metronomic doses of etoposide or cyclophosphamide on the peripheral blood Tregs and on the clinical outcome. The slope of the Tregs trend line was a significant predictor of an early relapse, even after controlling for stage and tumor residuum after the surgical debulking by using the Cox proportional hazard model.

CONCLUSIONS

This study shows that the faster kinetics of Tregs increase in the peripheral blood, expressed as the slope of the Tregs trend line, is a significant predictor of ovarian cancer early relapse hazard. However, due to its relatively low specificity, the informative value of regular monitoring of Tregs kinetics in the peripheral blood for the subsequent clinical outcome is limited.

Tumor antigen-specific monoclonal antibodies and induction of T-cell immunity

For decades the primary available cancer therapies were relatively nonspecific cytotoxic agents which, while effective in some patients, were limited by narrow therapeutic indices, extensive toxicity and development of resistance, likely due to tumor heterogeneity. Although these chemotherapies remain common tools of conventional treatment, the approval of a growing number of tumor antigen (TA)-specific monoclonal antibodies (mAbs) by the US Food and Drug Administration has driven a shift in the paradigm of cancer therapy. For a subset of patients with lymphoma, colorectal, head and neck, and breast cancers, the inclusion of rituximab (anti-CD20), cetuximab (anti-human epidermal growth factor 1), and trastuzumab (anti-human epidermal growth factor 2) has resulted in overall improved clinical response rates and survival advantages. The mechanisms that contribute to these effects are limited not only to inhibition of signaling pathways but also include cell-mediated cytotoxicity by innate immune cells and priming of effector cells of adoptive immunity triggered by the TA-specific mAb. However, as the use of these therapeutic mAbs has become more widespread, it has been observed that there is significant variability of response in patients treated with these agents. Thus, the factors that mediate this variability in clinical responses must be elucidated to optimize the use of TA-specific mAbs.

Cutaneous and oral squamous cell carcinoma-dual immunosuppression via recruitment of FOXP3+ regulatory T cells and endogenous tumour FOXP3 expression?

Regulatory T cells (Tregs) are an essential component of the immune system, but are also involved in the suppression of anti-tumour immune responses. The study examines their immunoregulatory role including their transcription factor, FOXP3, in oral and cutaneous SCC. Tregs were detected by double-immunohistochemistry. FOXP3-mRNA-expression was examined in tumour tissue, as well as in skin-derived primary cells and cell lines of different malignancy. Tregs were found in the tumour microenvironment, and FOXP3-mRNA-expression was significantly higher than in normal skin. Intriguingly, single FOXP3(+) cells exhibited morphologic characteristics of SCC cells. Consistent with this, endogenous FOXP3-mRNA-expression was indeed detected in the epidermal cell lineage and dramatically increased with increasing malignancy of the cells. SCCs recruit Tregs into their microenvironment, presumably in order to suppress immunosurveillance, thus avoiding destruction by the immune system. Endogenous FOXP3-expression in malignant epidermoid cells might present a novel mechanism of immune escape.

Pilot study of intratumoral injection of recombinant heat shock protein 70 in the treatment of malignant brain tumors in children

Intratumoral injections of recombinant heat shock protein (Hsp)70 were explored for feasibility in patients with brain tumors. Patients aged 4.5–14 years with untreated newly diagnosed tumors (n=12) were enrolled. After tumor resection, five injections of recombinant Hsp70 (total 2.5 mg) were administered into the resection cavity through a catheter. Before administration of Hsp70 and after the last injection, specific immune responses to the autologous tumor lysate were evaluated using the delayed-type hypersensitivity test. Further, peripheral blood was monitored to identify possible changes in lymphocyte subpopulations, cytokine levels, and the cytolytic activity of natural killer cells. The follow-up period in this trial was 12 months. Intratumoral injections of Hsp70 were well tolerated by patients. One patient had a complete clinical response documented by radiologic findings and one patient had a partial response. A positive delayed-type hypersensitivity test was observed in three patients. In peripheral blood, there was a shift from cytokines provided by Th₂ cells toward cytokines of a Th₁-cell-mediated response. These data corresponded to changes in lymphocyte subpopulations. Immunosuppressive T-regulatory cell levels were also reduced after injection of Hsp70, as well as production of interleukin-10. The cytolytic activity of natural killer cells was unchanged. The present study demonstrates the feasibility of intratumoral delivery of recombinant Hsp70 in patients with cancer. Further randomized clinical trials are recommended to assess the optimum dose of the chaperone, the treatment schedule, and clinical efficacy.

Large-scale evaluation of common variation in regulatory T cell-related genes and ovarian cancer outcome

The presence of regulatory T cells (Treg) in solid tumors is known to play a role in patient survival in ovarian cancer and other malignancies. We assessed inherited genetic variations via 749 tag single-nucleotide polymorphisms (SNP) in 25 Treg-associated genes (CD28, CTLA4, FOXP3, IDO1, IL10, IL10RA, IL15, 1L17RA, IL23A, IL23R, IL2RA, IL6, IL6R, IL8, LGALS1, LGALS9, MAP3K8, STAT5A, STAT5B, TGFB1, TGFB2, TGFB3, TGFBR1, TGRBR2, and TGFBR3) in relation to ovarian cancer survival. We analyzed genotype and overall survival in 10,084 women with invasive epithelial ovarian cancer, including 5,248 high-grade serous, 1,452 endometrioid, 795 clear cell, and 661 mucinous carcinoma cases of European descent across 28 studies from the Ovarian Cancer Association Consortium (OCAC). The strongest associations were found for endometrioid carcinoma and IL2RA SNPs rs11256497 [HR, 1.42; 95% confidence interval (CI), 1.22-1.64; P = 5.7 × 10(-6)], rs791587 (HR, 1.36; 95% CI, 1.17-1.57; P = 6.2 × 10(-5)), rs2476491 (HR, = 1.40; 95% CI, 1.19-1.64; P = 5.6 × 10(-5)), and rs10795763 (HR, 1.35; 95% CI, 1.17-1.57; P = 7.9 × 10(-5)), and for clear cell carcinoma and CTLA4 SNP rs231775 (HR, 0.67; 95% CI, 0.54-0.82; P = 9.3 × 10(-5)) after adjustment for age, study site, population stratification, stage, grade, and oral contraceptive use. The rs231775 allele associated with improved survival in our study also results in an amino acid change in CTLA4 and previously has been reported to be associated with autoimmune conditions. Thus, we found evidence that SNPs in genes related to Tregs seem to play a role in ovarian cancer survival, particularly in patients with clear cell and endometrioid epithelial ovarian cancer.

The ratios of CD8+ T cells to CD4+CD25+ FOXP3+ and FOXP3- T cells correlate with poor clinical outcome in human serous ovarian cancer

Ovarian cancer is an immune reactive malignancy with a complex immune suppressive network that blunts successful immune eradication. This suppressive microenvironment may be mediated by recruitment or induction of CD4⁺ regulatory T cells (Tregs). Our study sought to investigate the association of tumor-infiltrating CD4⁺CD25⁺FOXP3⁺ Tregs, and other immune factors, with clinical outcome in serous ovarian cancer patients. We performed immunofluorescence and quantification of intraepithelial tumor-infiltrating triple positive Tregs (CD4⁺CD25⁺FOXP3⁺), as well as CD4⁺CD25⁺FOXP3^-, CD3⁺ and CD8⁺ T cells in tumor specimens from 52 patients with high stage serous ovarian carcinoma. Thirty-one of the patients had good survival (i.e. > 60 months) and 21 had poor survival of < 18 months. Total cell counts as well as cell ratios were compared among these two outcome groups. The total numbers of CD4⁺CD25⁺FOXP3⁺ Tregs, CD4⁺CD25⁺FOXP3^-, CD3⁺ and CD8⁺ cells were not significantly different between the groups. However, higher ratios of CD8⁺/CD4⁺CD25⁺FOXP3⁺ Treg, CD8⁺/CD4⁺ and CD8/CD4⁺CD25⁺FOXP3^- cells were seen in the good outcome group when compared to the patients with poor outcome. These data show for the first time that the ratios of CD8⁺ to both CD4⁺CD25⁺FOXP3⁺ Tregs and CD4⁺CD25⁺FOXP3^- T cells are associated with disease outcome in ovarian cancer. The association being apparent in ratios rather than absolute count of T cells suggests that the effector/suppressor ratio may be a more important indicator of outcome than individual cell count. Thus, immunotherapy strategies that modify the ratio of CD4⁺CD25⁺FOXP3⁺ Tregs or CD4⁺CD25⁺FOXP3^- T cells to CD8⁺ effector cells may be useful in improving outcomes in ovarian cancer.

Inherited variants in regulatory T cell genes and outcome of ovarian cancer

Although ovarian cancer is the most lethal of gynecologic malignancies, wide variation in outcome following conventional therapy continues to exist. The presence of tumor-infiltrating regulatory T cells (Tregs) has a role in outcome of this disease, and a growing body of data supports the existence of inherited prognostic factors. However, the role of inherited variants in genes encoding Treg-related immune molecules has not been fully explored. We analyzed expression quantitative trait loci (eQTL) and sequence-based tagging single nucleotide polymorphisms (tagSNPs) for 54 genes associated with Tregs in 3,662 invasive ovarian cancer cases. With adjustment for known prognostic factors, suggestive results were observed among rarer histological subtypes; poorer survival was associated with minor alleles at SNPs in RGS1 (clear cell, rs10921202, p=2.7×10(-5)), LRRC32 and TNFRSF18/TNFRSF4 (mucinous, rs3781699, p=4.5×10(-4), and rs3753348, p=9.0×10(-4), respectively), and CD80 (endometrioid, rs13071247, p=8.0×10(-4)). Fo0r the latter, correlative data support a CD80 rs13071247 genotype association with CD80 tumor RNA expression (p=0.006). An additional eQTL SNP in CD80 was associated with shorter survival (rs7804190, p=8.1×10(-4)) among all cases combined. As the products of these genes are known to affect induction, trafficking, or immunosuppressive function of Tregs, these results suggest the need for follow-up phenotypic studies.

PLAU inferred from a correlation network is critical for suppressor function of regulatory T cells

Human FOXP3(+)CD25(+)CD4(+) regulatory T cells (Tregs) are essential to the maintenance of immune homeostasis. Several genes are known to be important for murine Tregs, but for human Tregs the genes and underlying molecular networks controlling the suppressor function still largely remain unclear. Here, we describe a strategy to identify the key genes directly from an undirected correlation network which we reconstruct from a very high time-resolution (HTR) transcriptome during the activation of human Tregs/CD4(+) T-effector cells. We show that a predicted top-ranked new key gene PLAU (the plasminogen activator urokinase) is important for the suppressor function of both human and murine Tregs. Further analysis unveils that PLAU is particularly important for memory Tregs and that PLAU mediates Treg suppressor function via STAT5 and ERK signaling pathways. Our study demonstrates the potential for identifying novel key genes for complex dynamic biological processes using a network strategy based on HTR data, and reveals a critical role for PLAU in Treg suppressor function.

T cell responses against microsatellite instability-induced frameshift peptides and influence of regulatory T cells in colorectal cancer

High-level microsatellite-unstable (MSI-H) colorectal carcinomas (CRC) represent a distinct subtype of tumors commonly characterized by dense infiltration with cytotoxic T cells, most likely due to expression of MSI-H-related frameshift peptides (FSP). The contribution of FSP and classical antigens like MUC1 and CEA to the cellular immune response against MSI-H CRC had not been analyzed so far. We analyzed tumor-infiltrating and peripheral T cells from MSI-H (n = 4 and n = 14, respectively) and microsatellite-stable (MSS) tumor patients (n = 26 and n = 17) using interferon gamma ELISpot assays. Responses against 4 FSP antigens and peptides derived from MUC1 to CEA were compared with and without depletion of regulatory T cells, and the results were related to the presence of the respective antigens in tumor tissue. Preexisting FSP-specific T cell responses were detected in all (4 out of 4) tumor-infiltrating and in the majority (10 out of 14) of peripheral T cell samples from MSI-H CRC patients, but rarely observed in MSS CRC patients. Preexisting T cell responses in MSI-H CRC patients were significantly more frequently directed against FSP tested in the present study than against peptides derived from classical antigens MUC1 or CEA (p = 0.049). Depletion of regulatory T cells increased the frequency of effector T cell responses specific for MUC1/CEA-derived peptides and, to a lesser extent, T cell responses specific for FSP. Our data suggest that the analyzed FSP may represent an immunologically relevant pool of antigens capable of eliciting antitumoral effector T cell responses.

Human prostate tumor antigen-specific CD8+ regulatory T cells are inhibited by CTLA-4 or IL-35 blockade

Regulatory T cells play important roles in cancer development and progression by limiting the generation of innate and adaptive anti-tumor immunity. We hypothesized that in addition to natural CD4(+)CD25(+) regulatory T cells (Tregs) and myeloid-derived suppressor cells, tumor Ag-specific Tregs interfere with the detection of anti-tumor immunity after immunotherapy. Using samples from prostate cancer patients immunized with a DNA vaccine encoding prostatic acid phosphatase (PAP) and a trans-vivo delayed-type hypersensitivity (tvDTH) assay, we found that the detection of PAP-specific effector responses after immunization was prevented by the activity of PAP-specific regulatory cells. These regulatory cells were CD8(+)CTLA-4(+), and their suppression was relieved by blockade of CTLA-4, but not IL-10 or TGF-β. Moreover, Ag-specific CD8(+) Tregs were detected prior to immunization in the absence of PAP-specific effector responses. These PAP-specific CD8(+)CTLA-4(+) suppressor T cells expressed IL-35, which was decreased after blockade of CTLA-4, and inhibition of either CTLA-4 or IL-35 reversed PAP-specific suppression of tvDTH response. PAP-specific CD8(+)CTLA-4(+) T cells also suppressed T cell proliferation in an IL-35-dependent, contact-independent fashion. Taken together, these findings suggest a novel population of CD8(+)CTLA-4(+) IL-35-secreting tumor Ag-specific Tregs arise spontaneously in some prostate cancer patients, persist during immunization, and can prevent the detection of Ag-specific effector responses by an IL-35-dependent mechanism.

Increased T regulatory cells are associated with adverse clinical features and predict progression in multiple myeloma

Background

Regulatory T (Treg) cells play an important role in the maintenance of immune system homeostasis. Multiple myeloma (MM) is a plasma cell disorder frequently associated with impaired immune cell numbers and functions.

Methods

We analyzed Treg cells in peripheral blood (n = 207) and bone marrow (n = 202) of pre-malignant and malignant MM patients using flow cytometry. Treg cells and their subsets from MM patients and healthy volunteers were functionally evaluated for their suppressive property. A cohort of 25 patients was analyzed for lymphocytes, CD4 T cells and Treg cells before and after treatment with cyclophosphamide, thalidomide plus dexamethasone (CTD).

Results

We found elevated frequencies of Treg cells in newly diagnosed (P<0.01) and relapsed MM patients (P<0.0001) compared to healthy volunteers. Also, Treg subsets including naïve (P = 0.015) and activated (P = 0.036) Treg cells were significantly increased in MM patients compared to healthy volunteers. Functional studies showed that Treg cells and their subsets from both MM and healthy volunteers were similar in their inhibitory function. Significantly increased frequencies of Treg cells were found in MM patients with adverse clinical features such as hypercalcemia (>10 mg/dL), decreased normal plasma cell (≤5%) count and IgA myeloma subtype. We also showed that MM patients with ≥5% of Treg cells had inferior time to progression (TTP) (13 months vs. median not reached; P = 0.013). Furthermore, we demonstrated the prognostic value of Treg cells in prediction of TTP by Cox regression analysis (P = 0.045). CTD treatment significantly reduced frequencies of CD4 T cells (P = 0.001) and Treg cells (P = 0.018) but not Treg cells/CD4 T cells ratio compared to pre-treatment.

Conclusions

Our study showed immune deregulation in MM patients which is evidenced by elevated level of functionally active Treg cells and patients with increased Treg cells have higher risk of progression.

Tumor-infiltrating γδ T lymphocytes predict clinical outcome in human breast cancer

Understanding and dissecting the role of different subsets of regulatory tumor-infiltrating lymphocytes (TILs) in the immunopathogenesis of individual cancer is a challenge for anti-tumor immunotherapy. High levels of γδ regulatory T cells have been discovered in breast TILs. However, the clinical relevance of these intratumoral γδ T cells is unknown. In this study, γδ T cell populations were analyzed by performing immunohistochemical staining in primary breast cancer tissues from patients with different stages of cancer progression. Retrospective multivariate analyses of the correlations between γδ T cell levels and other prognostic factors and clinical outcomes were completed. We found that γδ T cell infiltration and accumulation in breast tumor sites was a general feature in breast cancer patients. Intratumoral γδ T cell numbers were positively correlated with advanced tumor stages, HER2 expression status, and high lymph node metastasis but inversely correlated with relapse-free survival and overall survival of breast cancer patients. Multivariate and univariate analyses of tumor-infiltrating γδ T cells and other prognostic factors further suggested that intratumoral γδ T cells represented the most significant independent prognostic factor for assessing severity of breast cancer compared with the other known factors. Intratumoral γδ T cells were positively correlated with FOXP3(+) cells and CD4(+) T cells but negatively correlated with CD8(+) T cells in breast cancer tissues. These findings suggest that intratumoral γδ T cells may serve as a valuable and independent prognostic biomarker, as well as a potential therapeutic target for human breast cancer.

Regulation of COX2 expression in mouse mammary tumor cells controls bone metastasis and PGE2-induction of regulatory T cell migration

Background

The targeting of the immune system through immunotherapies to prevent tumor tolerance and immune suppression are at the front lines of breast cancer treatment and research. Human and laboratory studies have attributed breast cancer progression and metastasis to secondary organs such as the bone, to a number of factors, including elevated levels of prostaglandin E2 (PGE2) and the enzyme responsible for its production, cyclooxygenase 2 (COX2). Due to the strong connection of COX2 with immune function, we focused on understanding how variance in COX2 expression manipulates the immune profile in a syngeneic, and immune-competent, mouse model of breast cancer. Though there have been correlative findings linking elevated levels of COX2 and Tregs in other cancer models, we sought to elucidate the mechanisms by which these immuno-suppressive cells are recruited to breast tumor and the means by which they promote tumor tolerance.

Methodology/Principal Findings

To elucidate the mechanisms by which exacerbated COX2 expression potentiates metastasis we genetically manipulated non-metastatic mammary tumor cells (TM40D) to over-express COX2 (TM40D-COX2). Over-expression of COX2 in this mouse breast cancer model resulted in an increase in bone metastasis (an observation that was ablated following suppression of COX2 expression) in addition to an exacerbated Treg recruitment in the primary tumor. Interestingly, other immune-suppressive leukocytes, such as myeloid derived suppressor cells, were not altered in the primary tumor or the circulation. Elevated levels of PGE2 by tumor cells can directly recruit CD4+CD25+ cells through interactions with their EP2 and/or EP4 receptors, an effect that was blocked using anti-PGE2 antibody. Furthermore, increased Treg recruitment to the primary tumor contributed to the greater levels of apoptotic CD8+ T cells in the TM40D-COX2 tumors.

Conclusion/Significance

Due to the systemic effects of COX2 inhibitors, we propose targeting specific EP receptors as therapeutic interventions to breast cancer progression.

Immunophenotypic identification and characterization of tumor cells and infiltrating cell populations in meningiomas

Meningiomas are primary tumors of the central nervous system composed of both neoplastic and other infiltrating cells. We determined the cellular composition of 51 meningioma samples by multiparameter flow cytometric (MFC) immunophenotyping and investigated the potential relationship between mRNA and protein expression levels of neoplastic cells. For immunophenotypic, morphologic, and cytogenetic characterization of individual cell populations, a large panel of markers was used together with phagocytic/endocytic functional assays and MFC sorting. Overall, our results revealed coexistence of CD45(-) neoplastic cells and CD45(+) immune infiltrating cells in all meningiomas. Infiltrating cells included tissue macrophages, with an HLA-DR(+)CD14(+)CD45(+)CD68(+)CD16(-/+)CD33(-/+) phenotype and high phagocytic/endocytic activity, and a small proportion of cytotoxic lymphocytes (mostly T CD8(+) and natural killer cells). Tumor cells expressed multiple cell adhesion proteins, tetraspanins, HLA-I/HLA-DR molecules, complement regulatory proteins, cell surface ectoenzymes, and growth factor receptors. Noteworthy, the relationship between mRNA and protein levels was variable, depending on the proteins evaluated and the level of infiltration by immune cells. In summary, our results indicate that MFC immunophenotyping provides a reliable tool for the characterization of the patterns of protein expression of different cell populations coexisting in meningioma samples, with a more accurate measure of gene expression profiles of tumor cells at the functional/protein level than conventional mRNA microarray, independently of the degree of infiltration of the tumor by immune cells.

T cells in gastric cancer: friends or foes

Gastric cancer is the second cause of cancer-related deaths worldwide. Helicobacter pylori is the major risk factor for gastric cancer. As for any type of cancer, T cells are crucial for recognition and elimination of gastric tumor cells. Unfortunately T cells, instead of protecting from the onset of cancer, can contribute to oncogenesis. Herein we review the different types, "friend or foe", of T-cell response in gastric cancer.

Tumour cell generation of inducible regulatory T-cells in multiple myeloma is contact-dependent and antigen-presenting cell-independent

Regulatory T-cells (T_Reg cells) are increased in patients with multiple myeloma (MM). We investigated whether MM cells could generate and/or expand T_Reg cells as a method of immuno-surveillance avoidance. In an in vitro model, CD4⁺CD25^-FoxP3^- T-cells co-cultured with malignant plasma cells (primary MM cells and cell lines) induced a significant generation of CD4⁺CD25⁺FoxP3⁺ inducible T_Reg cells (tT_Reg cells; p<0.0001), in a contact-dependent manner. tT_Reg cells were polyclonal, demonstrated a suppressive phenotype and phenotypically, demonstrated increased FoxP3 (p = 0.0001), increased GITR (p<0.0001), increased PD1 (p = 0.003) and decreased CD62L (p = 0.007) expression compared with naturally occurring T_Reg cells. FACS-sorted tT_Reg cells differentiated into FoxP⁺IL-17⁺ and FoxP3^-IL-17⁺ CD4⁺ cells upon TCR-mediated stimulation. Blocking experiments with anti-ICOS-L MoAb resulted in a significant inhibition of tT_Reg cell generation whereas both IL-10 & TGFβ blockade did not. MM tumour cells can directly generate functional T_Reg cells in a contact-dependent manner, mediated by ICOS/ICOS-L. These features suggest that tumour generation of T_Reg cells may contribute to evasion of immune surveillance by the host.

Inflammation driven by tumour-specific Th1 cells protects against B-cell cancer

The immune system can both promote and suppress cancer. Chronic inflammation and proinflammatory cytokines such as interleukin (IL)-1 and IL-6 are considered to be tumour promoting. In contrast, the exact nature of protective antitumour immunity remains obscure. Here, we quantify locally secreted cytokines during primary immune responses against myeloma and B-cell lymphoma in mice. Strikingly, successful cancer immunosurveillance mediated by tumour-specific CD4⁺ T cells is consistently associated with elevated local levels of both proinflammatory (IL-1α, IL-1β and IL-6) and T helper 1 (Th1)-associated cytokines (interferon-γ (IFN-γ), IL-2 and IL-12). Cancer eradication is achieved by a collaboration between tumour-specific Th1 cells and tumour-infiltrating, antigen-presenting macrophages. Th1 cells induce secretion of IL-1β and IL-6 by macrophages. Th1-derived IFN-γ is shown to render macrophages directly cytotoxic to cancer cells, and to induce macrophages to secrete the angiostatic chemokines CXCL9/MIG and CXCL10/IP-10. Thus, inflammation, when driven by tumour-specific Th1 cells, may prevent rather than promote cancer.

Inflammation can result in the formation of tumours, but the immune system is also involved in the elimination of cancer cells. Here, the authors show that inflammation driven by tumour-specific CD4⁺ T cells results in tumour regression and identify a list of cytokines associated with cancer prevention.

Tumor-infiltrating programmed death receptor-1+ dendritic cells mediate immune suppression in ovarian cancer

Within the ovarian cancer microenvironment, there are several mechanisms that suppress the actions of antitumor immune effectors. Delineating the complex immune microenvironment is an important goal toward developing effective immune-based therapies. A dominant pathway of immune suppression in ovarian cancer involves tumor-associated and dendritic cell (DC)-associated B7-H1. The interaction of B7-H1 with PD-1 on tumor-infiltrating T cells is a widely cited theory of immune suppression involving B7-H1 in ovarian cancer. Recent studies suggest that the B7-H1 ligand, programmed death receptor-1 (PD-1), is also expressed on myeloid cells, complicating interpretations of how B7-H1 regulates DC function in the tumor. In this study, we found that ovarian cancer-infiltrating DCs progressively expressed increased levels of PD-1 over time in addition to B7-H1. These dual-positive PD-1(+) B7-H1(+) DCs have a classical DC phenotype (i.e., CD11c(+)CD11b(+)CD8(-)), but are immature, suppressive, and respond poorly to danger signals. Accumulation of PD-1(+)B7-H1(+) DCs in the tumor was associated with suppression of T cell activity and decreased infiltrating T cells in advancing tumors. T cell suppressor function of these DCs appeared to be mediated by T cell-associated PD-1. In contrast, ligation of PD-1 expressed on the tumor-associated DCs suppressed NF-κB activation, release of immune regulatory cytokines, and upregulation of costimulatory molecules. PD-1 blockade in mice bearing ovarian cancer substantially reduced tumor burden and increased effector Ag-specific T cell responses. Our results reveal a novel role of tumor infiltrating PD-1(+)B7-H1(+) DCs in mediating immune suppression in ovarian cancer.

Increased frequency of CD4+CD25(high)FoxP3+ regulatory T cells in patients with hepatocellular carcinoma

Accumulating evidence suggests regulatory T cells (Tregs) are associated with impaired antitumor responses. However, the relationship between the CD4(+)CD25(high)FoxP3(+) Treg and hepatocellular carcinoma (HCC) has not been well investigated. Levels of CD4(+)CD25(high)FoxP3(+) Tregs in peripheral blood mononuclear cells (PBMCs) from HCC patients and healthy donors, tumor infiltrating lymphocytes (TILs) extracted from HCC, and hepatic lymphocytes extracted from resected liver were measured by flow cytometry, and their effects on T-cell proliferation was determined by (3)H-thymidine incorporation. Serum levels of interleukin (IL)-10 and transforming growth factor (TGF)-β1 were measured by enzyme linked immunosorbent assay. The frequency of Tregs in PBMCs from HCC patients was higher than that from healthy donors. Similarly, the frequency of Tregs in TILs was higher than that of hepatic lymphocytes. On the other hand, the (3)H-thymidine uptake by TILs and PBMCs from HCC patients was decreased drastically when compared to the counterparts from normal controls. Furthermore, serum IL-10 and TGF-β1 levels increased significantly in HCC patients when compared to the healthy donors. This study identified an increased frequency of CD4(+)CD25(high)FoxP3(+) Tregs in patients with HCC. The elevated serum IL-10, TGF-β1 levels also correlated with impaired antitumor responses in these patients. Further effort is needed to establish new immunotherapeutic strategies designed to modulate Tregs to promote a competent antitumor response.

Immunity and immune suppression in human ovarian cancer

Clinical outcomes in ovarian cancer are heterogeneous, independent of common features such as stage, response to therapy and grade. This disparity in outcomes warrants further exploration into tumor and host characteristics. One compelling issue is the response of the patient's immune system to her ovarian cancer. Several studies have confirmed a prominent role for the immune system in modifying disease course. This has led to the identification and evaluation of novel immune-modulating therapeutic approaches such as vaccination and antibody therapy. Antitumor immunity, however, is often negated by immune suppression mechanisms present in the tumor microenvironment. Thus, in the future, research into immunotherapy targeting ovarian cancer will probably become increasingly focused on combination approaches that simultaneously augment immunity while preventing local immune suppression. In this article, we summarize important immunological issues that could influence ovarian cancer outcome, including tumor antigens, endogenous immune responses, immune escape and new and developing immunotherapeutic strategies.

Tumor infiltrating regulatory T cells: tractable targets for immunotherapy

Several studies have linked tumor-infiltration by regulatory T cells with poor patient outcome. Targeting the mechanisms by which regulatory T cells traffic to and persist in the tumor may circumvent tumor immune-escape by de-restricting T cell-mediated cytotoxicity. In this review, we describe the principle axes that govern regulatory T cell migration and the mechanisms that underpin their immunosuppressive activity in cancer. Inhibiting either the migration or function of regulatory T cells may enhance host-anti-cancer immune responses and as such are attractive and tractable targets for therapeutic intervention.